The present invention is related to the detection of bacteria, such as Mycobacteria, in human or animal body fluids such as blood, sputum and urine. The present invention provides a method for assessing the viability of bacteria such as Mycobacterium tuberculosis without the need for propagation of the bacteria. The method of the present invention is in particular useful for assessing the viability of Mycobacteria species such as are M. tuberculosis or M. leprae. With the present invention oligonucleotides are provided that can be used as primers and probes for the amplification of bacterial EF-Tu mRNA. The use of the oligonucleotides according to the invention is not limited to any particular amplification technique or any particular modification thereof. It is evident that the oligonucleotides according to the invention find their use in many different nucleic aid amplification techniques and various methods for detecting the presence of (amplified) bacterial EF-Tu mRNA.

The present invention is related to the detection of bacteria, such as Mycobacteria, in human or animal body fluids such as blood, sputum and urine. The present invention provides a method for assessing the viability of bacteria such as Mycobacterium tuberculosis without the need for propagation of the bacteria.
For example, tuberculosis (TB) caused by Mycobacterium tuberculosis is a major public health problem in many countries world-wide with particular significance in developing countries. Tuberculosis control programmes are faced with an increased burden of cases, a shift towards diagnostically more difficult categories of patients such as extrapulmonary and smear-negative cases, and the emergence of multidrug-resistant strains of M. tuberculosis. Improved diagnosis would be a valuable contribution in the struggle to solve this global public health emergency.
The method of the present invention is concerned with the amplification of specific nucleic acid sequences.
Nucleic acid amplification reactions promise to reduce the time for diagnosis from weeks to hours, while surpassing the sensitivity and specificity of the classical methods. Besides their potential value in diagnosis, amplification reactions offer the possibility of a rapid identification and drug-susceptibility determination. Amplification of DNA target molecules to a detectable level by the polymerase chain reaction (PCR) is the best analyzed system for detecting Mycobacteria.
The xe2x80x9cPolymerase Chain Reactionxe2x80x9d (PCR) is described in European patent applications EP 200362 and EP 201148. PCR is a cyclic process which has double stranded DNA as target. Each cycle in the PCR process starts with the separation of a double stranded DNA target in its two complementary strands. To each strand a primer will anneal and DNA polymerases present will extend the primers along the DNA strand to which it annealed thus forming two new DNA duplexes. When the reaction mixture is heated the strands of the DNA duplexes will be separated again and a new PCR cycle can start. Thus, the PCR process produces multiple DNA copies of a DNA target. Amplification using PCR, can also be based on an RNA template. The actual PCR needs to be preceded by a reverse transcription step to copy the RNA into DNA (RT-PCR). However, if RT-PCR is used for the detection of transcripts differentiation of mRNA- and DNA-derived PCR products is necessary. DNAse treatment prior to RT-PCR can be employed (Bitsch, A. et al., J Infect. Dis 167, 740-743., 1993; Meyer, T. et al., Mol. Cell Probes. 8, 261-271., 1994), but sometimes fails to remove contaminating DNA sufficiently [Bitsch, A. et al., 1993].
More recently a different class of nucleic acid amplification methods namely the xe2x80x9ctranscription based amplification techniquesxe2x80x9d was developed. The techniques involve the transcription of multiple RNA copies from a template comprising a promoter recognized by an RNA polymerase. Said copies are used as input for further amplification. Such methods have been described by Gingeras et al. in WO88/10315 and Burg et al. in WO89/1050. Isothermal transcription based amplification techniques have been described by Davey et al. in EP 323822 (relating to the NASBA method), by Gingeras et al. in EP 373960 and by Kacian et al. in EP 408295 (the TMA method). Transcription based amplification reactions may also be performed with thermostable enzymes. Such a thermostable method is described in EP 682121 filed in the name of Toyo Boseki KK.
The isothermal transcription based nucleic acid amplification techniques have been utilized to detect mycobacteria, such as the NASBA method [Vliet, G. M. E. van der, Schukkink, R. A. F., Gemen, B. van, Schepers, P. and Klatser, P. R. (1993) Nucleic acid sequence-based amplification (NASBA) for the identification of mycobacteria. J. Gen. Microbiol. 139, 2423-2429.] and another transcription-mediated RNA amplification test (TMA)[Jonas, V., Alden, M. J., Curry, J. I., Kamisango, K., Knott, C. A., Lankford, R., Wolfe, J. and Moore, D. F. (1993) Detection and identification of Mycobacterium tuberculosis directly from sputum sediments by amplification of rRNA. J. Clin. Microbiol. 31, 241] both targeted at 16S ribosomal RNA.
Amplification reactions targeted at the 16S rRNA or the gene encoding it are usually directed to a conserved region which comprises species-specific variable sequences [Vliet, G. M. E. van der, Schukkink, R. A. F., Gemen, B. van, Schepers, P. and Klatser, P. R. (1993) Nucleic acid sequence-based amplification (NASBA) for the identification of mycobacteria. J. Gen. Microbiol. 139, 2423-2429., Jonas, V., Alden, M. J., Curry, J. I., Kamisango, K., Knott, C. A., Lankford, R., Wolfe, J. and Moore, D. F. (1993) Detection and identification of Mycobacterium tuberculosis directly from sputum sediments by amplification of rRNA. J. Clin. Microbiol. 31, 241]. They have the advantage that a single amplification reaction can identify the mycobacterial species. An additional advantage of the transcription-mediated RNA amplification assays targeted at 16S rRNA, is the high number of target molecules per cellxe2x88x92xc2x12000; sensitivity is thereby favoured.
Since RNA, especially mRNA, has a generally much shorter half-life time than DNA, its detection may be useful for the assessment of the viability of mycobacteria [Moore, D. F., Curry, J. I., Knott, C. A. and Jonas, V. (1996) Amplification of rRNA for assessment of treatment response of pulmonary tuberculosis patients during antimicrobial therapy. J. Clin. Microbiol. 34, 1745-1749., Vliet, G. M. E. van der, Schepers, P., Schukkink, R. A. F., Gemen, B. van and Klatser, P. R. (1994) Assessment of mycobacterial viability by RNA amplification. Antimicrob. Agents Chemother. 38, 1959-1965.], which is relevant to the problems of resistance against drugs and contagiousness of the patient.
The present invention is based on the detection of mRNA encoding the elongation factor EF-Tu.
The elongation factor EF-Tu is essential in (myco)bacterial translation. Elongation factors play an ancillary role in the elongation step of translation and are thus an indicator of the cell""s metabolic activity. For every translation EF-Tu is required. The amount of EF-Tu protein can be as high as 50% of their total protein content in active proliferating cells.
EF-Tu encoding gene sequences (DNA) have been used as a marker to detect the presence of bacterial cells.
In EP133288 a method is disclosed for the detection of bacterial DNA with a probe comprising a base sequence of at least a portion of one of the strands of a tuf or fus gene. Southern blot hybridization of the digested mycoplasmal DNAs with the elongation factor (EF-Tu) gene tuf of E.coli was used as a basis to detect polymorphism in mycoplasma strains.[Yogev et al. FEMS Microbiol.Lett., 50(2-3), 145-9, 1988].
A PCR based assays for the detection of Mycoplasma tuberculosis, and Mycoplasma fermentans using the gene encoding elongation factor Tu (tuf) as the target sequence had also been described [Berg et al.,Mol.Cell.Probes, 10(1), 7-14, 1996 and Luneberg et al., J.Clin.Microbiol., 31(5), 1088-94, 1993].
The present invention, however, is concerned with the detection of EF-Tu mRNA as a marker for bacterial viability.
The present invention thus provides a method for the assessment of bacterial viability whereby mRNA coding for the elongation factor EF-Tu is used as a target in a nucleic acid amplification reaction and the presence and/or amount of said mRNA is determined.
The presumably short-lived mRNA coding for the EF-Tu is most likely highly abundant in the (myco)bacterial cell and a decrease therein will indicate a decline in metabolic activity. Furthermore, because of the EF-Tu""s essential role, it is plausible to assume that it is present in all mycobacterial species, allowing the development of a general amplification system with species-specific primers and/or probes, analogous to the 16S rRNA NASBA design [Vliet, G. M. E. van der, Schukkink, R. A. F., Gemen, B. van, Schepers, P. and Klatser, P. R. (1993) Nucleic acid sequence-based amplification (NASBA) for the identification of mycobacteria. J. Gen. Microbiol. 139, 2423-24291.].
With the method of the present invention, preferably a transcription based amplification technique, such a NASBA, is used for the amplification of the bacterial EF-Tu mRNA. In contrast to RT-PCR, NASBA, which is based on RNA transcription by T7 RNA polymerase (Kievits et al., 1991; Compton, 1991), does not need differentiation between RNA- and DNA-derived amplification products since it uses RNA as its principal target.
The amplified products may be detected using a complementary labeled probe.
Numerous protocols have been described for the detection of amplified products [Klatser, P R. (1995) Amplification reactions in mycobacteriology. J. Microbiol. Meth. 23, 75-87.]. Preferably homogeneous assays are used, because they would allow amplification reaction mixtures to be sealed before amplification is initiated. One such system, electro-chemiluminescence (ECL), has already been succesfully applied to detect amplified products in NASBA [Gemen, B. van, Beuningen, R. van, Nabbe, A., Strijp, D. van, Jurriaans, S., Lens, P., Kievits, T. (1994) A one-tube quantitative HIV-I RNA NASBA nucleic acid amplification assay using electrochemiluminescent (ECL) labelled probes. J. Virol. Methods, 49, 157-167.].
The method of the present invention is in particular useful for assessing the viability of Mycobacteria species such as are M. tuberculosis or M. leprae.
With the present invention oligonucleotides are also provided that can be used as primers and probes for the amplification of bacterial EF-Tu mRNA.
The use of the oligonucleotides according to the invention is not limited to any particular amplification technique or any particular modification thereof. It is evident that the oligonucleotides according to the invention find their use in many different nucleic acid amplification techniques and various methods for detecting the presence of (amplified) bacterial EF-Tu mRNA. The oligonucleotides of the present invention can likewise be used in quantitative amplification methods. An example of such quantitative method is described in EP 525882.
The term xe2x80x9coligonucleotidexe2x80x9d as used herein refers to a molecule comprised of two or more deoxyribonucleotides or ribonucleotides. Such oligonucleotides may be used as primers and probes.
Of course, based on the sequences of the oligonucleotides of the present invention, analogues of oligonucleotides can also be prepared. Such analogues may constitute alternative structures such as xe2x80x9cPNAxe2x80x9d (molecules with a peptide-like backbone instead of the phosphate sugar backbone of normal nucleic acid) or the like. It is evident that these alternative structures, representing the sequences of the present invention are likewise part of the present invention.
The term xe2x80x9cprimerxe2x80x9d as used herein refers to an oligonucleotide either naturally occurring (e.g. as a restriction fragment) or produced synthetically, which is capable of acting as a point of initiation of synthesis of a primer extension product which is complementary to a nucleic acid strand (template or target sequence) when placed under suitable conditions (e.g. buffer, salt, temperature and pH) in the presence of nucleotides and an agent for nucleic acid polymerization, such as DNA dependent or RNA dependent polymerase. A primer must be sufficiently long to prime the synthesis of extension products in the presence of an agent for polymerization. A typical primer contains at least about 10 nucleotides in length of a sequence substantially complementary or homologous to the target sequence, but somewhat longer primers are preferred. Usually primers contain about 15-26 nucleotides but longer primers may also be employed, especially when the primers contain additional sequences such as a promoter sequence for a particular polymerase.
Normally a set of primers will consist of at least two primers, one xe2x80x98upstreamxe2x80x99 and one xe2x80x98downstreamxe2x80x99 primer which together define the amplificate (the sequence that will be amplified using said primers).
Primarily for the use in transcription based amplification techniques, the oligonucleotides according to the invention may also be linked to a promoter sequence. The term xe2x80x9cpromoter sequencexe2x80x9d defines a region of a nucleic acid sequence that is specifically recognized by an RNA polymerase that binds to a recognized sequence and initiates the process of transcription by which an RNA transcript is produced. In principle any promoter sequence may be employed for which there is a known and available polymerase that is capable of recognizing the initiation sequence. Known and useful promoters are those that are recognized by certain bacteriophage RNA polymerases such as bacteriophage T3, T7 or SP6. Oligonucleotides linked to a promoter sequence are commonly referred to as xe2x80x9cpromoter primersxe2x80x9d.
Oligonucleotides according to the invention are substantially complementary to a sequence of a bacterial EF-Tu mRNA sequence, said oligonucleotide being 10-50 nucleotides in length and comprising at least 10 consecutive nucleotides of one of the sequences depicted in SEQ ID 1-8 or the complementary sequence thereof.
Oligonucleotides comprising (a part of) SEQ ID""s 1 and 2 have proven to be suitable for the amplification of Ef-Tu mRNA sequences of M. tuberculosis. In the event amplification is carried out with a transcription based amplification technique one of said oligonucleotides may also comprise a promoter sequence. Of course, such xe2x80x9cpromoter-oligonucleotidesxe2x80x9d are likewise art of the invention. In the sequence as depicted in SEQ ID 9 the T7 promoter has been linked to the sequence as depicted in SEQ ID 1. In the experimental part of this application these sequences are indicated as TUF15 (SEQ ID 9) and TUF 18 (SEQ ID 2).
The present invention also provides a pair of oligonucleotides for the amplification of M. leprae derived EF-Tu sequences. This pair consists of an oligonucleotide comprising at least 10 consecutive nucleotides of the sequence as. depicted in SEQ ID 3 and an oligonucleotide comprising at least 10 consecutive nucleotides of the sequence as depicted in SEQ ID 4 respectively.
Again, for use in transcription based methods, one of the oligonucleotides may be linked to a promoter sequence, and an oligonucleotide provided with the T7 promoter sequence is depicted in SEQ ID 10. In the experimental part of the application such a pair is referred to as TUF 20 (SEQ ID 10) and TUF 22 (SEQ ID 4).
The present invention further provides a pair of oligonucleotides that are suitable for the amplification of E. coli derived EF-Tu sequences.
This pair consists of an oligonucleotide comprising at least 10 consecutive nucleotides of the sequence. as depicted in SEQ ID 5 and an oligonucleotide comprising at least 10 consecutive nucleotides of the sequence as depicted in SEQ ID 6 respectively.
Again, for use in transcription based methods, one of the oligonucleotides may be linked to a promoter sequence, and an oligonucleotide provided with. the T7 promoter sequence is depicted in SEQ ID 11. In the experimental part of the application such a pair is referred to as TUF 27 (SEQ ID. 11) and TUF 27 (SEQ ID 6).
These oligonucleotides are thus especially useful in the assessment of the viability of M.tuberculosis, M.Leprae or E.coli.
It is understood that oligonucleotides consisting of the sequences of the present invention may contain minor deletions, additions and/or substitutions of nucleic acid bases, to the extent that such alterations do not negatively affect the yield or product obtained to a significant degree. Where oligonucleotides according to the present invention are used as probes, the alterations should not result in lowering the hybridization efficiency of the probe.
For example, in case of transcription based amplification techniques, wherein one or more of the primers may be provided with a promoter sequence, the introduction of a purine-rich (=G or A) hybridizing sequence, just after the promoter sequence may have positive effects on the transcription (when there are C""s and T""s abortive transcription may occur). If no such sequence is available in the target nucleic acid a purine-rich sequence can be inserted in the oligonucleotide just following the last three G residues of the promoter sequence.
The sequences of the present invention are reflected as DNA sequences. The RNA equivalents of these sequences are likewise part of the present invention.
Part of the oligonucleotides according to the invention are particularly suitable for use as a probe in the detection of nucleic acid amplified with a pair of oligonucleotides according to the invention. When used as a probe, said oligonucleotides may be provided with a detectable label. Various labeling moieties are known in the art. Said moiety may, for example, either be a radioactive compound, a detectable enzyme (e.g. horse radish peroxidase (HRP)), a hapten like biotin, or any other moiety capable of generating a detectable signal such as a calorimetric, fluorescent, chemiluminescent or electrochemiluminescent signal.
Hybrids between oligonucleotides according to the invention and (amplified) target nucleic acid may also be detected by other methods known to those skilled in the art. Oligonucleotides according to the invention that are especially suitable as a probe for the detection of Mycobacterial Ef-Tu sequences consist essentially of the sequences as depicted in SEQ ID 7 and 8 (In the experimental part said sequences are depicted as TUF 25 and TUF 26 respectively.).
Together these probes can be used in a sandwich hybridization assay, whereby one can be used as capture probe and the other can be labeled with a detectable label.
A test kit for the detection of Mycobacterial EF-Tu mRNA in a sample is likewise part of the present invention. Such a kit may comprise
a pair of oligonucleotides according to the invention and at least one oligonucleotide comprising a nucleic acid sequence substantially complementary to at least part of the amplified nucleic acid sequence, provided with a detectable label, as well as suitable amplification reagents.
These reagents are for example the suitable enzymes for carrying out the amplification reaction. A kit, adapted for use with NASBA for example, may contain suitable amounts of reverse transcriptase, RNase H and T7 RNA polymerase. Said enzymes may be present in the kit in a buffered solution but can likewise be provided as a lyophilized composition, for example, a lyophilized spherical particle. Such lyophilized particles have been disclosed in PCT appl. no. WO95/27721. The kit may further be furnished with buffer compositions, suitable for carrying out an amplification reaction. Said buffers may be optimized for the particular amplification technique for which the kit is intended as well as for use with the particular oligonucleotides that are provided with the kit. In transcription based amplification techniques, such as NASBA, said buffers may contain, for example, DMSO, which enhances the amplification reaction (as is disclosed in PCT appl. no. WO 91/02818).
Furthermore the kit may be provided with an internal control as a check on the amplification procedure and to prevent the occurrence of false negative test results due to failures in the amplification procedure. The use of internal controls in transcription based amplification techniques is described in PCT appl. no. WO 94/04706. An optimal control sequence is selected in such a way that it will not compete with the target nucleic acid in the amplification reaction. Kits may also contain reagents for the isolation of nucleic acid from biological specimen prior to amplification. A suitable method for the isolation of nucleic acid is disclosed in EP389063.

EF-Tu mRNA as a marker for viability of bacteria


A liquid crystal display device according to the present invention is directed at optimizing the viewing angle characteristics of black luminance in a diagonal direction by realizing a low tilt angle without depending on an oriented film or an orientation treatment method in an FFS mode. The liquid crystal display device of the present invention is a liquid crystal display device in the FFS mode, including: a liquid crystal layer having a negative dielectric anisotropy; a color filter substrate disposed to sandwich the liquid crystal layer; and a TFT substrate having pixels, wherein a CF side common electrode which controls a potential is present in a liquid crystal layer side of the color filter substrate; and there is electric field controlling means which forms an alternating electric field between the CF side common electrode and a TFT side common electrode.

1. Field of the Invention
The present invention relates to a liquid crystal display device, which is particularly improved in viewing angle characteristics on a tilt angle in fringing field switching (FFS) and has wide viewing angle characteristics.
2. Description of the Related Art
Liquid crystal display devices have been used in various displays for computers, televisions, and the like because of having excellent characteristics of a small thickness, a light weight, and a low power consumption.
There are various operation modes of the liquid crystal display panels of the liquid crystal display devices. Examples of such operation modes are: a TN (Twisted Nematic) mode in which liquid crystal molecules between two glass substrates are twisted and oriented; an IPS (In-Plane Switching) mode in which an electric field is transversely applied by a pair of two electrodes formed on one glass substrate to rotate liquid crystal molecules; an FFS (Fringing field switching) mode in which the alignment of liquid crystal molecules is controlled by a fringe electric field between common and pixel electrodes formed to be laminated on one glass substrate; and the like. In each of the operation modes of the liquid crystal display panels, the quantity of light passing through a liquid crystal display panel is changed to display by making light from a backlight incident on the liquid crystal display panel and by controlling the alignment of liquid crystal molecules by a voltage.
FIG. 1 is a cross-sectional view that illustrates the structure of a liquid crystal display panel 519 in the FFS mode. The liquid crystal display panel 519 in FIG. 1 is composed of: a TFT substrate 502 and a color filter substrate 504 which are affixed to each other at a kept certain distance; and a liquid crystal layer 505 sandwiched between the two substrates (1999 SID International Symposium Digest of Technical Papers, "A Novel Wide-Viewing-angle Technology: Ultra-Trans View", (p. 202) (Non Patent Literature 1)).
The TFT substrate 502 is composed of: a thin film transistor and various wirings which are not illustrated; two transparent electrodes 510 and 511 which are laminated to sandwich an insulating film 513 and include ITO and the like; and an oriented film 518 which includes polyimide and the like and is subjected to orientation treatment, on a glass substrate 501. The transparent electrode 511 disposed in a side closer to the liquid crystal layer 505 in the two transparent electrodes 510 and 511 is provided with openings to control the alignment of liquid crystal molecules 517 in the liquid crystal layer 505 by a fringe electric field 525 generated between the two transparent electrodes.
In contrast, in the color filter substrate 504 affixed to the TFT substrate 502, a black matrix which is not illustrated and a color resist which is not illustrated are formed on a glass substrate 501, an overcoat which covers the black matrix and the color resist and is not illustrated is laminated, and an oriented film 518 subjected to orientation treatment in the same manner as in the array substrate is then formed.
The orientation of the liquid crystal molecules 517 in the liquid crystal layer 505 sandwiched between the TFT substrate 502 and the color filter substrate 504 is controlled by the oriented film 518 when no voltage is applied. As the oriented film 518, an organic film such as a polyimide film is typical. In order to control the orientation of the liquid crystal molecules 517 in approximately parallel to a substrate surface, the organic film is subjected to orientation treatment for giving orientation, such as rubbing treatment, irradiation with light such as ultraviolet rays, or ion irradiation. Therefore, the orientation state of the liquid crystal molecules 517 during application of no voltage depends greatly on the orientation treatment and the material of the oriented film.
Examples of parameters indicating the orientation state of the liquid crystal molecules 517 include anchoring energy, a pretilt angle, and the like. The anchoring energy is a measure that represents how the liquid crystal molecules 517 are bound to an interface (oriented film) while the pretilt angle PT is a measure that represents how the liquid crystal molecules 517 tilt with respect to a substrate plane (oriented film surface) as illustrated in FIG. 2. Since the liquid crystal molecules 517 are going to align in the same direction relative to each other, the tilt angle T of the liquid crystal molecules 517 in a bulk of the liquid crystal layer 505 during application of no voltage is in the state of being tilting from the substrate surface due to the pretilt angle PT.
The tilt angle T in the TN mode, the IPS mode, or the FFS mode is approximately parallel to a substrate. However, the pretilt angle PT depends on an orientation treatment condition such as rubbing, the alkyl side or main chain of polyimide used in the oriented film 518, burning temperature, and the like. Therefore, when a tilt angle T in a bulk of liquid crystal layer 505 is measured by a crystal rotation method, tilt is generally found to be at 1 to 10°.
In the FFS mode, increase in the tilt angle T of the liquid crystal molecules 517 results in increase in the black luminance of the liquid crystal display device in a horizontal or vertical direction or a diagonal direction and therefore results in decrease in the contrast of the liquid crystal display device. Therefore, it is necessary to design the tilt angle T of the liquid crystal molecules 517 in the FFS mode to be as low as near zero.
For controlling the tilt angle T, an orientation treatment condition such as rubbing is an important parameter, and a parameter such as the alkyl side or main chain of polyimide used in the oriented film 518 or burning temperature is found to have a great influence. Furthermore, when the tilt angle T approaches zero, the tilt angle T is determined by the main chain of polyimide.
Although it is easy to simply decrease only the tilt angle T, it is necessary for the oriented film 518 to satisfy various product characteristics. Examples of the characteristics required for the oriented film 518 are uniform orientation, durability against rubbing, abnormal orientation due to generated cutting scrap, the uniformity of the film thickness of the oriented film 518, electric characteristics such as visual persistence, and the like. Therefore, there has not been known any method for simultaneously satisfying the low tilt angle T and the characteristics in the oriented film 518 used in the FFS mode.
Then, Japanese Patent Laid-Open No. 2000-356786 (Patent Literature 1) discloses a method for disposing a conductor layer (electrode) on a substrate in an opposite side in a liquid crystal display device in an FFS mode. In the patent publication, there is described a technology in which liquid crystal molecules having a negative dielectric anisotropy are used, an electric field generated between a pixel electrode and a common electrode, which electric field contains many components perpendicular to the substrate, is generated, and the liquid crystal molecules are controlled to be driven in a plane horizontal to the substrate by a synthetic electric field obtained as a result of overlapping the electric field and an electric field generated between the pixel electrode and an electrode disposed on the opposite side substrate. Furthermore, there is described a technology in which an electrode disposed on the opposite side substrate has a constant potential.
In Japanese Patent Laid-Open No. 2001-091974 (Patent Literature 2), the potential of a signal line is changed depending on other display data, an unnecessary electric field is therefore applied between the signal line and a pixel electrode (or a common electrode) in the external side of a pixel, such an electric field controlling electrode as to cover the edge of the signal line is disposed on an opposed substrate in order to improve leakage of light due to the electric field, a voltage with an opposite sign is applied between the electric field controlling electrode and the signal line, and a perpendicular electric field is applied in order to put liquid crystal molecules in a direction perpendicular to the substrate in a region between the signal line and the pixel electrode (or the common electrode) in the external side of the pixel.

In-plane switching mode liquid crystal display device


A novel lancet device is disclosed, and the lancet device is compact and is designed to be held like a writing instrument during use. The device has a trigger relatively close to a firing end so the device can be easily maintained in the desired position while the device is being fired. A cocking knob on the device is rotated one hundred eighty degrees in order to cock the device and prepare the device for use. Only a relatively small amount of rotational force is needed to rotate the cocking knob. The device provides that a lancing needle does not extend and become exposed when the device is cocked. A thumb button is provided on the device, and the thumb button doubles as a depth adjustment knob and an ejector button. The thumb button can be pressed in order to simultaneously eject a tip platform along with the lancing needle, and can be turned in order to set the depth at which the lancing needle will pierce the fingertip when the device is fired. The thumb button can be pushed or rotated without applying an excessive amount of force.

The present invention relates generally to a lancet device for lancing a human fingertip to obtain a small amount of blood for diagnostic purposes, and relates more specifically to a novel lancet device which is held like a writing instrument while being used to lance a fingertip.
In many situations, it is desirable to obtain a small amount of human blood for diagnostic purposes. For example, a person who is diabetic may want to obtain a small amount of his or her blood in order to test the blood-sugar level thereof and determine whether an insulin shot should be administered.
Presently, lancet devices are available for a person to use to lance a fingertip. Typically, these devices have a "firing" end from which a lancing needle extends through a hole when the device is "fired." While these devices are generally effective, the devices which are presently available present many disadvantages. For example, many of the devices are bulky and difficult to hold. Moreover, many of the devices have a "trigger", or actuator button, relatively far from the firing end. As a result, it is difficult for a user to maintain the firing end of the device against the fingertip while firing the device. Additionally, many of the presently available devices provide that the lancing needle extends from the firing end as the device is being "cocked", or prepared for firing, and fail to provide that the lancing needle can be quickly and easily removed and disposed of after the device is fired. Consequently, one may get accidentally stuck by the lancing needle while removing the lancing needle from the device. While this accidental sticking may not be especially detrimental in a situation such as when a person who is diabetic is personally using the lancet device at home to lance him or herself, this accidental sticking by the lancing needle may be extremely undesirable in some situations such as when a nurse is using the lancet device on a patient who has AIDS.
While some of the devices presently available provide that the lancing needle can be ejected without having to touch the lancing needle, these devices require that one remove a tip platform before ejecting the lancing needle. However, the tip platform may also have blood thereon because the tip platform is placed against the fingertip immediately before the device is fired, and when the device is fired, the lancing needle extends through and retracts back into a hole in the tip platform. Because the tip platform may have blood thereon, it is desirable to avoid having to touch the tip platform in order to eject the lancing needle.
Other disadvantages presented by the lancet devices that are presently available include requiring a great amount of force from the user in order to cock the device, fire the device, or eject the lancing needle from the device.
For the foregoing reasons, there is a need for a novel lancet device structured in accordance with the present invention. The present invention is directed to eliminated the problems discussed hereinabove.


A method for forming a pattern for preventing the formation of water marks on a semiconductor substrate during drying the semiconductor substrate after forming a resist pattern on the semiconductor substrate using a photoresist, is disclosed. An insulating layer is formed on the semiconductor substrate and the resist pattern is formed on the insulating layer. The resist pattern is exposed to ultraviolet rays to reduce the hydrophobicity of the surface portion of the resist pattern. Then, the exposed portion of the insulating layer by the resist pattern is wet etched by using the resist pattern as an etching mask. The sheet off time of deionized water from the surface of the resist pattern is lengthened. The semiconductor substrate becomes relatively hydrophobic when compared to the resist pattern. And the sheet off time of the remaining deionized water on the semiconductor substrate is shorter than that of the deionized water on the resist pattern. Accordingly, the deionized water on the surface of the semiconductor substrate can be advantageously removed.

1. Field of the Invention
The present invention relates to a method for forming a pattern, and more particularly to a method for forming a pattern for preventing the generation of water marks on a semiconductor substrate during drying of the semiconductor substrate after forming an insulating layer of a semiconductor device.
2. Prior Art
Generally, an insulating layer stacked on a semiconductor substrate is patterned into a predetermined shape by using a photolithography process for forming a mask, and using a wet etching process or a dry etching process.
FIGS. 1A & 1B illustrate a method for forming a pattern on a semiconductor substrate using a conventional wet etching process. Referring to FIG. 1A, an insulating layer 12 is firstly formed on a semiconductor substrate 10 by depositing an insulating material such as silicon oxide to have a predetermined thickness and then a photoresist layer 14 is formed on insulating layer 12 by coating a photoresist through a spin-coating method. Next, an opening 16 for exposing a portion of insulating layer 12 to be etched, is formed by pre-baking, exposing by using a mask having a predetermined pattern and then developing photoresist layer 14 by a common photo process. Photoresist pattern 14 is subject to hard-baking for increasing an etching resistance and an adhesiveness of photoresist pattern 14, and for removing remaining solvent.
Now, referring to FIG. 1B, insulating layer 12 is wet etched by using resist pattern 14 including opening 16 as an etching mask and using buffered oxide etchant (BOE: a mixture of NH.sub.4 F:HF=6:1 in volume ratio) as an etching solution which includes hydrogen fluoride. Then, a portion of insulating layer 12 exposed by opening 16 is removed to form an insulating pattern 12A. Next, semiconductor substrate 10 is rinsed in deionized water, and then dried in a dryer to remove the deionized water. Then, the remaining resist pattern 14 is removed by stripping.
Through the above-described method, after insulating layer 12 is patterned by using resist pattern 14 as an etching mask, semiconductor substrate 10 including the remaining resist pattern 14 is immersed into the deionized water, and then the deionized water is removed. At this time, a portion of the deionized water remains partially on semiconductor substrate 10. FIG. 2 illustrates deionized water 18 remaining on the exposed portion of semiconductor substrate 10 between insulating pattern 12A and an adjacent insulating pattern after the deionized water is removed.
The deionized water can be removed by a subsequent drying process. However, water marks are formed on the semiconductor substrate by the remaining deionized water. The water mark formed before forming a gate oxide layer becomes a contaminant. The water mark acts as an oxygen supplying source when the gate oxide layer is formed by a thermal oxidation process, to thereby form a locally thick oxide layer. This results in the electrical failure of the semiconductor device.
It is reported that the reason for the formation of the water mark depends on the wettability of silicon. (see: Effect of Drying Methods and Wettability of Silicon on the Formation of Water Marks in Semiconductor Processing by Jin-Goo Park and Michael F. Pas, J. Electrochem. Soc., Vol. 142, No. 6, pp2028-2031). According to Park et al., a hydrophilic wafer does not form the water marks by any kind of drying method such as a spin drying method, a vapor drying method, etc., while a hydrophobic wafer forms a lot of the water marks by the spin drying method. Further, a wafer having uniform hydrophilic surface or hydrophobic surface does not form the water marks during subsequent vapor drying. However, a wafer having a surface including both the hydrophilic portion and hydrophobic portion forms the water marks after isopropyl alcohol (IPA) vapor drying process after the patterning process. That is, a wafer having the hydrophilic surface, from which water can be removed uniformly during drying, does not form the water marks, while a wafer having a large difference in wettability of silicon forms a lot of the water marks. Accordingly, the difference in the wettability of the wafer surface plays an important role in formation of the water marks.
The wet etching process using hydrogen fluoride when forming the gate oxide layer is widely used. The surface of the semiconductor substrate or insulating layer exposed to the wet etching process using hydrogen fluoride has high hydrophobicity.
The resist pattern formed by the photoresist is made of organic materials and so is hydrophobic. The hydrophobicity of the resist pattern having such hydrophobicity is different from that of the surface of the semiconductor substrate or the insulating layer transformed to be hydrophobic. The water marks are thought to be formed because of these differences.

Method for forming a pattern preventing water mark formation


An intelligent robot cleaner setting a travel path based on a video learning includes a travel driver, a suction unit, an image acquisition unit, and a controller. The travel driver moves to an area to be cleaned along the travel path. The suction unit sucks foreign substances on the travel path. The image acquisition unit acquires an image on the travel path. The controller analyzes the image, decides whether an object is present on the travel path, classifies a type of the object, and sets a bypass travel path that avoids the object if the object is an avoidance object.

A robot cleaner sucks dust and foreign substances on a floor corresponding to an area to be cleaned while moving along a predetermined travel path. A travel path through which the robot cleaner moves is set in advance. Since various obstacles may exist on the travel path, measures are sought to cope with the obstacles.
To cope with the obstacles, in a related art, it was common to identify the obstacles that obstruct the movement of the robot cleaner and set a travel path by bypassing the corresponding obstacles.
However, various obstacles may exist in the area to be cleaned in addition to obstacles that obstruct the movement of the robot cleaner. For example, as the number of users living with companion animals increases, the number of companion animal feces increases in the area to be cleaned. Since contaminants such as companion animal feces do not interfere with the movement of the robot cleaner, the related art robot cleaner moves on the area with the contaminants on the travel path. Hence, there arises a problem that the area to be cleaned becomes more difficult to clean. Alternatively, since small-sized valuables, etc. do not interfere with the movement of the robot cleaner, the robot cleaner sucks the valuables, etc. in the process of cleaning along a fixed travel path. As described above, as the robot cleaner moves without recognizing them as an obstacle, the area to be cleaned may be further messed up or there is a risk of losing valuables.
Alternatively, even if an obstacle on the travel path is an object that does not obstruct the movement of the robot cleaner, the robot cleaner may avoid the obstacle. Hence, there is a disadvantage that the cleaning is performed insufficiently.

Intelligent robot cleaner for setting travel route based on video learning and managing method thereof


An ion implantation cluster tool for implanting ions into a workpiece is provided, wherein a plurality of beamline assemblies having a respective plurality of ion beamlines associated therewith are positioned about a common process chamber. Each of the plurality of ion beamline assemblies are selectively isolated from the common process chamber, and the plurality of beamline intersect at a processing region of the process chamber. A scanning apparatus positioned within the common process chamber is operable to selectively translate a workpiece holder in one or more directions through each of the plurality of ion beamlines within the processing region, and a common dosimetry apparatus within the common process chamber is operable to measure one or more properties of each of the plurality of ion beamlines. A load lock chamber is operably coupled to the common process chamber for exchange of workpieces between the common process chamber and an external environment.

In the manufacture of semiconductor devices, ion implantation systems are employed to dope a semiconductor wafer or other workpiece with impurities. In such systems, an ion source ionizes a desired dopant element, which is extracted from the source in the form of an ion beam. The ion beam is typically mass analyzed to select ions of a desired charge-to-mass ratio and then directed at the surface of a semiconductor wafer in order to implant the wafer with the dopant element. The ions of the beam penetrate the surface of the wafer to form a region of desired conductivity, such as in the fabrication of transistor devices in the wafer. A typical ion implanter includes an ion source for generating the ion beam, a beamline assembly including a mass analysis apparatus for mass resolving the ion beam using magnetic fields, and a target chamber containing the semiconductor wafer or workpiece to be implanted by the ion beam.
Typically, the ions generated from the ion source are formed into a beam and directed along a predetermined beam path to an implantation station. The ion beam implanter may further include beam forming and shaping structures extending between the ion source and the implantation station. The beam forming and shaping structures maintain the ion beam and bound an elongated interior cavity or passageway through which the beam passes en route to the implantation station. When operating the ion implanter, this passageway is typically evacuated to reduce the probability of ions being deflected from the predetermined beam path as a result of collisions with air molecules.
The mass of an ion relative to the charge thereon (i.e., charge-to-mass ratio) affects the degree to which it is accelerated both axially and transversely by an electrostatic or magnetic field. Therefore, the beam that reaches a desired area of a semiconductor wafer or other target can be made very pure since ions of undesirable molecular weight will be deflected to positions away from the beam and implantation of other than desired materials can be avoided. The process of selectively separating ions of desired and undesired charge-to-mass ratios is known as mass analysis. Mass analyzers typically employ a mass analysis magnet creating a dipole magnetic field to deflect various ions in an ion beam via magnetic deflection in an arcuate passageway that will effectively separate ions of different charge-to-mass ratios.
The ion beam is focused and directed at a desired surface region of the workpiece in the target station, wherein the energetic ions of the ion beam are accelerated to a predetermined energy level to penetrate into the bulk of the workpiece. The ions, for example, are embedded into the crystalline lattice of the material to form a region of desired conductivity, with the energy of the ion beam generally determining the depth of implantation. The ion beam may be a spot beam (e.g., a pencil beam), wherein the workpiece is mechanically scanned in two dimensions orthogonal to the generally stationary spot beam; a ribbon beam, wherein the beam is electromagnetically scanned in one direction across the workpiece while the workpiece is mechanically scanned in an orthogonal direction; or an electromagnetically scanned beam that is electromagnetically scanned in two directions across a stationary workpiece. Examples of ion implantation systems include those available from Axcelis Technologies of Beverly, Mass.
Conventionally, a typical ion implantation system comprises a processing chamber, wherein the workpiece resides on a workpiece holder within the processing chamber during implantation. The processing chamber maintains a processing environment that is typically separate from other environments, wherein cross-contamination from the processing environment to the other environments is generally limited. In an ion implantation system employing a mechanical scanning of the workpiece, the workpiece holder is typically coupled to a scanning device within the processing chamber, wherein the scanning device is operable to move the workpiece holder in one or more directions with respect to the ion beam. Further, a beam monitoring device (such as a Faraday cup) is typically aligned with the ion beam within the process chamber for process feedback.
In some processing schemes, cluster tools are utilized to perform several different processes on a single workpiece, wherein the workpiece is transported between various processing environments within the cluster tool. For example, FIG. 1 illustrates a conventional cluster tool 10, wherein the cluster tool is configured to perform a variety of processes on a workpiece 15. The cluster tool 10, for example, comprises a first ion implanter 20, a second ion implanter 25 an etch station 30, a resist asher 35, and a load lock chamber 40 surrounding a central workpiece transfer station 45. Each of the first ion implanter 20, second ion implanter 25, etch station 30, and resist asher 35 comprises its own respective independent processing chamber 50A-50D that is selectively isolated from the workpiece transfer station 45 by respective gate valves 55A-55D, wherein each processing chamber has an independent processing environment 60A-60D for processing the workpiece 15. Further, each processing chamber 50A-50D comprises its own workpiece holder 65A-65D, wherein, in the case of the first and second ion implanters 20 and 25, the workpiece holders 65A and 65B are further coupled to a respective first and second scanning device 70A and 70B. Still further, in the case of the first and second ion implanters 20 and 25, a respective first and second beam monitoring device 75A and 75B are positioned within the respective processing chambers 50A and 50B for monitoring respective first and second ion beamlines 80A and 80B associated with the respective implanter.
In operation, the workpiece 15 is conventionally transferred between the plurality of processing chambers 50A-50D by a workpiece handler 80, based on the desired processing of the workpiece. For example, when differing ion species are desired to be implanted into the workpiece 15, the first and second ion beamlines 85A and 85B of the respective first and second ion implanters 20 and 25 are configured to have differing ion species associated therewith. Accordingly, the workpiece 15 is transferred from the load lock chamber 40 through the gate valve 55A to the first processing chamber 50A and placed on the workpiece holder 65A coupled to the first scanning device 70A within the processing chamber 50A. The gate valve 55A is then closed, the first processing chamber 50A is evacuated, and the workpiece 15 is scanned through the first beamline 85A via the first scanning device 70A, wherein the first beamline is monitored by the first beam monitoring device 75A within the processing chamber 50A.
Once the desired implant by the first implanter 20 is complete, the gate valve 55A is opened, and the workpiece 15 is transferred out of the processing chamber 50A of the first implanter and back into the transfer station 45. The workpiece is 15 is then transferred through the gate valve 55B into the processing chamber 50B of the second implanter 25 and placed on the workpiece holder 65B coupled to the second scanning device 70B within the processing chamber 50B of the second implanter. The gate valve 55B is then closed, and the processing chamber 50B is evacuated. The workpiece 15 is then scanned through the second beamline 85B of the second implanter 25 via the second scanning device 70B, wherein the second beamline is monitored by the second beam monitoring device 75B within the processing chamber 50B. When the desired implant by the second implanter 25 is complete, the gate valve 55B is opened, and the workpiece 15 is transferred out of the processing chamber 50B of the second implanter and back into the transfer station 45, wherein further processing may or may not be performed.
The conventional cluster tool described above, however, is costly, since each ion implantation system 20 and 25 has its own respective dedicated process chamber 50A and 50B, scanning device 70A and 70B, beam monitoring device 75A and 75B, and typically, its own controller (not shown) for controlling each implantation system. Therefore, it is desirable to provide an improved ion implantation system cluster tool, wherein efficiencies can be increased by sharing common components between multiple ion beamlines, thus decreasing ownership costs associated with having multiple beamlines.


The present invention is directed to a Shock Absorbing Grip Assembly that has been designed to give a controlled floating action to the grip that can be adjusted by varying the different cushioning isolator mechanisms within the grip, or by varying the number of tuning washers. The Shock Absorbing Grip Assembly is comprised of one or more grip end clamps; one or more cavities in said grip end clamps; a grip sleeve having one or more protruding engagement members; one or more elastomeric isolator inserts housed within each of said one or more cavities in said grip end clamps, wherein said one or more protruding engagement members mates within said cavities housing said elastomeric isolator inserts; and an outer elastomer grip; whereby said grip sleeve is free floating and has torsional, rotational, linear and axial shock absorbing capacity. The isolator inserts may be elastomer inserts of varying durometer material.

Handlebar grips have been utilized on the ends of handlebars for decades. These grips are typically made of a soft polymer that both improves a users' ability to grasp the handlebars and cushions the hand against the effect of vibrations and sudden impacts.
The handlebar grips are preferably made of anti-skid, relatively elastic and low durometer polymer such as rubber or urethane to enhance the cushioning effects. In off-road cycling, whether self-propelled, as in mountain biking, or powered by an internal combustion engine, as in a motorcycle, or riding an all-terrain vehicle (ATV), the rider tends to grip the handle bars tightly for balance and control. Under competitive conditions, the rider may need to enhance his/her grip for prolonged periods of time while traversing difficult terrain. Such tight gripping by the rider tends to cause shocks to be transferred to the rider's hands, wrists, forearms and related extremities. Over a period of time, these various forces can induce fatigue, and fatigue can compromise riding enjoyment and competitive results in racing.
By creating a torsional, rotational, linear and axial cushioning effect on the handlebar the Shock Absorbing Grip Assembly insure that the riders hands, wrists, forearms and related extremities are relieved from the shocks incurred during prolonged activity.
Although attempts have been made to provide handle-bar grips that are comfortable to use, ones that are too-soft do not provide adequate motion control. Those that provide good motion control tend to be too-stiff to be comfortable. Thus, there is a need for a handle bar grip that is comfortable to use, that provides precise motion control, that has good endurance, and that can be readily retro-fitted on existing handle bars.
Numerous innovations for the handlebar grip have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present design as hereinafter contrasted. The following is a summary of those prior art patents most relevant to this application at hand, as well as a description outlining the difference between the features of the Shock Absorbing Grip Assembly and the prior art.
U.S. Pat. No. 7,013,533 of Wayne R. Lumpkin describes a grip for a cycle that includes a cylindrical liner extending along a liner axis between a first and a second end. The cylindrical liner has at least two elongate slots extending axially along a lengthwise portion of the cylindrical liner, each elongate slot overlapping a lengthwise part of another elongate slot, the overlapping elongate slots being radially offset. An over molding overlies a lengthwise of the cylindrical liner. The elongate slots are preferably disposed in a first set of at least two elongate slots extending along a first axial line in the liner and a second set of at least two elongate slots extending along a second axial line in the liner. The first and second axial lines are radially offset and the first set of elongate slots overlaps the second set of elongate slots. A first elongate slot may intercept a first end of the cylindrical liner. A compression member is provided in operative association with a circumference of an axial segment of the cylindrical liner. The axial segment includes at least a lengthwise portion of the first elongate slot. The compression member is operable between a relaxed state not compressing the axial segment and a compression segment compressing the axial segment about its circumference. The axial segment is preferably proximate the first end of the cylindrical liner.
This patent describes a grip with a cylindrical liner that has at least two elongate slots extending axially along a lengthwise portion of the cylindrical liner, each elongate slot overlapping a lengthwise part of another elongate slot, the overlapping elongate slots being radially offset. This patent does not use the elastomeric isolator members to isolate the grip portion from the handle bar giving the secure but floating sensation.
U.S. Pat. No. 8,484,806 of Gregory S. Rarick describes an ergonomic hand grip assembly. The assembly includes an outer resilient cover having an open proximal end surrounded by an annular flange. The cover is preferably molded of elastomeric material, such as rubber, that provides a satisfactory co-efficient of friction with respect to the palm of a human hand when gripped adjacent the cover flange. The elastomeric material is of conventional rubber-like composition known in art for use on outdoor equipment having a handle bar control member. The control member has a free end portion which is moveable by a user's hand to provide control motion inputs to a vehicle and to assist the vehicle rider in maintaining balance while riding the vehicle.
This patent describes an ergonomic hand grip assembly but does not use the elastomeric isolator members to isolate the grip portion from the handle bar giving the secure but floating sensation.
None of these previous efforts, however, provides the benefits attendant with the Shock Absorbing Grip Assembly. The present design achieves its intended purposes, objects and advantages over the prior art devices through a new, useful and unobvious combination of method steps and component elements, with the use of a minimum number of functioning parts, at a reasonable cost to manufacture, and by employing readily available materials.
In this respect, before explaining at least one embodiment of the Shock Absorbing Grip Assembly in detail, it is to be understood that the design is not limited in its application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings.


The invention concerns a method for estimating the transfer function of a multicarrier signal transmission channel consisting of a temporal succession of symbols of a set of data elements, each of the data elements modulating a carrier frequency of the signal, the data elements comprising pilots and so-called informative data elements. The invention is characterized in that said method comprises: a step which consists in determining a set of two-dimensional discrete prolate spheroidal sequences (DPSS); a step which consists in writing the transfer function in the form of a combination of at least some of the two-dimensional discrete prolate spheroidal sequences (DPSS); a step which consists in time-based and frequency-based two-dimensional interpolation of at least some of the coefficients of the combination, so as to obtain an estimation of the transfer function at any point of a time-frequency network.

Multicarrier modulations associated with error correction coding and interlacing have demonstrated their advantages particularly for high speed transmissions in a radio mobile environment as illustrated in patents FR-86 09622 and FR-95 05455 dealing with the OFDM (Orthogonal Frequency Division Multiplexing) modulation and IOTA (Isotropic Orthogonal Transform Algorithm) modulation.
In the case of a coherent demodulation of received data, it is essential to be able to make a good estimate of the channel at all points in a time-frequency plane, in order to correctly demodulate the information received by the receiver.
In particular, the invention relates to optimisation of channel estimating techniques in the case of a multiple carrier transmission, called multicarrier transmission.
Usually, when data are transmitted on a radio channel at high speed, the signal is subjected to Doppler effects (related to movements of the transmitter, receiver or any reflectors) and multiple path problems (for example related to reflection of the signal on different objects) causing a delay spread or variations of the signal amplitude. These effects depend particularly on the time and frequency considered. Thus, a channel with a variable time and frequency is complex and it has to be estimated correctly in order to be able to decode received data reliably.
According to the state of the art, in the case of a multicarrier modulation, the channel estimate from which degradations caused by a radio mobile channel can best be corrected, consists of the following steps:                insert reference carriers into the flow of information carriers at locations known to the receiver;        making use of values taken by these references in reception, to deduce the channel transfer function at these points in the time-frequency plane; and        starting from these results, obtain the channel transfer function on all points in a time-frequency network.
There are two particular methods of doing this:                the estimate by scattered pilots; in transmission, pilot symbols are distributed regularly in the time-frequency plane. An undersampled version of the channel is obtained starting from these pilots. In reception, a two-dimensional interpolation is carried out in time and frequency to determine the value of the channel at all points in the time-frequency network. This method is used particularly by the DVB-T (Digital Video broadcasting —Terrestrial) standard.        the estimate by reference multicarrier symbol (also called preamble); at least one reference symbol is placed at the beginning of a frame emitted on the channel. With this or these symbols, the channel is estimated in reception of the frame transmitted on each carrier. The channel can be considered as being quasi-static on a given frame (choice of system parameters such that the channel varies slowly compared with the symbol time), the channel estimate on the reference symbol(s) is valid for all OFDM symbols in the frame (in particular this method is applied to the ETSI (European Telecommunication Standard Institute) HIPERLAN/2 standard.
In the case of a scattered pilots estimate, the complexity of the channel estimator is usually limited by using two single-dimensional interpolation filters instead of a two-dimensional filter. The implementation complexity is then significantly lower for an acceptable degradation of the estimating quality.
For example for DVB-T, a Wiener filter is used for the frequency interpolation while the time interpolation is a simple linear interpolation. The linear interpolation is not optimum but its complexity is lower than the complexity of a two-dimensional FIR filter or two single-dimensional FIR filters in cascade.
Therefore, the interpolation is done in time and then in frequency.
Furthermore, it is difficult to make a Wiener filter adaptive, in other words to recalculate the coefficients of the reception filter as a function of the channel parameters. Consequently, it systematically becomes necessary to size the filter for the worst Doppler and delay spread case.
In particular, the purpose of the invention is to overcome these disadvantages of prior art.
More precisely, one purpose of the invention is to optimise decoding of a data frame emitted on a channel with a strong Doppler spread when multicarrier modulation is used.
Another objective is to optimise the estimate of the transfer function of a transmission channel within the framework of a multicarrier transmission.
Another purpose of the invention is to enable a fairly simple interpolation of the channel transfer function over an entire time-frequency network starting from estimated values of this function at locations of pilot symbols inserted in the transmitted data frame.
Another purpose of the invention is to offer a good compromise between the useful flow and the quality of the channel estimate.

Method for estimating the transfer function of a multicarrier signal transmission channel and corresponding receiver


Methods and compounds for conferring site-specific or local immune privilege.

Instances of unwanted immune responses, e.g., as in the rejection of transplanted tissue or in autoimmune disorders, constitute a major health problem for millions of people across the world. Long-term outcomes for organ transplantation are frequently characterized by chronic rejection, and eventual failure of the transplanted organ. More than twenty autoimmune disorders are known, affecting essentially every organ of the body, and affecting over fifty million people in North America alone. The broadly active immunosuppressive medications used to combat the pathogenic immune response in both scenarios have serious side effects.


Devices and methods for providing an enhanced navigation solution are disclosed that involve detecting correction events along a trajectory of a device. Platform speed is estimated based on characteristics of the correction events, such as by estimating speed of turn during the turn of the platform so that a navigation solution is enhanced by correcting the trajectory of the platform using the estimated speed.

Electronic devices, such as portable devices configured to be handheld or otherwise associated with a user, are employed in a wide variety of applications and environments. Increasingly, such devices are equipped with one or more sensors or other systems for determining the position or motion of the device. Notably, portable devices such as smartphones, tablets, smart watches or others or portable devices may feature Global Navigation Satellite Systems (GNSS) receivers, low cost Micro Electro-Mechanical Systems (MEMS) inertial sensors, barometers and magnetometers. GNSS and multi-sensors can be integrated to provide promising positioning results in most outdoor environments. Moreover, these characteristics also apply to other types of electronic devices that may not fall within the category of portable devices. For example, similar technologies may be employed with dedicated telematic devices specifically configured to record motion and other navigational and usage information. Such devices may be installed as part of a vehicle manufacturing process or subsequently, either by the owner or by an interested third party such as an insurance company that uses the information for actuarial or other purposes.
There are clear benefits associated with the capability of providing seamless positioning capabilities in all kinds of environments such as malls, offices or underground parking lots. In the absence of GNSS signals in indoor environments, the conventional strapdown Inertial Navigation System (SINS) that uses low cost inertial sensors, suffers significant performance degradation due to the accumulated sensor drifts and bias. As such, positioning technologies relying solely on motion sensors may not satisfy all requirements for seamless indoor and outdoor navigation applications. Dead Reckoning (DR) is an example of indoor/outdoor positioning techniques, and has become the focus of industrial and academic research recently. Similar to the SINS, DR accumulates successive displacement from a known starting point to derive the position. This displacement can be estimated with various algorithms within a certain accuracy using the inertial sensor measurements. Nevertheless, inertial sensor based positioning techniques still suffer from accumulating errors.
Accordingly, it would be desirable to provide navigation techniques that can be corrected to improve the accuracy and reliability of positioning applications for any device having suitable motion sensors. Further, it would be desirable to obtain such correction even in the absence of other navigation strategies, such as when GNSS or other absolute position information is unavailable. It would also be desirable to achieve these goals using techniques that reduce computational demands and require fewer processing resources, allowing them to be implemented in cost and power efficient manners. As will be described in the following materials, this disclosure satisfies these and other needs.

System and method for position correction


In order to use so-called gray water for the flushing of toilets, for example in a conveyance such as a passenger aircraft, the gray water is passed through at least one filter, preferably through a coarse filter followed by a fine filter, into a treatment tank where it is anodically oxidized. The rinsing is performed by a pump that may be a rotary pressure pump or a piston cylinder pump. The pump passes the processed or oxidized water through an excess pressure valve and through at least one spray nozzle into a toilet bowl.

Commercial aircraft currently carry fresh water for the flushing of vacuum operated toilets in these aircraft. Moreover, the lavatory basins also use freshwater which, by its use in the handwash basin becomes so called "gray water". Thus, in the passenger lavatories substantial quantities or volumes of gray water are produced, which conventionally are not used for any further purpose. The inventors have discovered that following a simple treatment or processing of this gray water it would be quite suitable for use as toilet flushing water.

Method and apparatus for processing and re-using of gray water for flushing toilets


A catalytic upgrading process includes introducing a feed comprising crude oil to a first catalytic deasphalting reactor to deasphalt the feed, thereby producing polymerized asphaltenes and deasphalted oil (DAO). The DAO is introduced to a steam cracking unit, thereby producing pyrolysis gas (PG), which is introduced into a selective hydrogenation unit, thereby producing an olefin-free product, which can then be introduced to a separation unit. The resulting benzene-toluene-xylenes (BTX)-containing stream and liquid petroleum gas (LPG) are separated, and the BTX-containing stream is introduced to a BTX complex to produce refined BTX. After deasphalting, a wash solvent may be introduced into the first catalytic deasphalting reactor to remove the polymerized asphaltenes, regenerate the catalyst, and produce a mixture comprising the wash solvent and the polymerized asphaltenes. The wash solvent is separated from the polymerized asphaltenes.

Asphaltenes are the heaviest and most polar compounds naturally occurring in crude oil, which typically includes asphaltenes in concentrations ranging from 1% by weight to 17% by weight, and they are also identified as a major factor in causing difficulties during crude oil transportation and refining. Asphaltenes are one of the four main substances believed to be soluble in crude oils at atmospheric pressure and ambient temperature, the others being saturates, aromatics, and resins. However, unlike resins, asphaltenes contain highly polar species that tend to associate, and as a result, the interactions of asphaltenes with the environment are very complex.
Asphaltenes are a mixture of high molecular weight polycyclic aromatic hydrocarbons and heterocyclic compounds, primarily comprising carbon, hydrogen, nitrogen, oxygen, and sulfur, as well as trace amounts of vanadium and nickel. In asphaltenes, the hydrogen-to-carbon atomic ratio is approximately 1.2:1.0. Asphaltenes are defined operationally as n-pentane or n-heptane-insoluble, toluene-soluble components of a carbonaceous material such as crude oil, and are a sticky, black, highly viscous residue of distillation processes.
All aspects of crude oil production and refining may be negatively impacted by asphaltenes. For example, asphaltenes precipitation or deposition can occur in wellbores, pipelines, and surface facilities, limiting well productivity and fluid flow. Further, asphaltenes may poison the refining catalysts or may clog the refining system, causing damage and lost productivity for oil refineries.
Conventional asphaltenes separation, which may utilize Solvent Deasphalting (SDA) technology, involves applying paraffinic solvents (n-propane, n-butane, n-pentane, n-hexane, or n-heptane) to perform liquid-liquid extraction, to produce higher-value Deasphalted Oil (DAO). However, the SDA process requires a considerable amount of expensive paraffinic solvents (the solvent to crude oil ratio is typically from 2:1 to 10:1 by volume). Furthermore, the separation and recovery of paraffinic solvents from DAO are energy-intensive processes.

Integrated process with a deasphalting column for crude oil direct catalytic upgrading


A method and apparatus for allocating frequency resources for peer to peer (P2P) communication between terminals without a base station are provided. The method determines resources used for a direct communication between two terminals in a communication system. The method includes determining uplink frequency resources of a cellular communication system for use in the direct communication between the two terminals, determining a primary maximum transmission power to minimize interference caused by the direct communication on the cellular communication system and performing the direct communication between the two terminals by using the uplink frequency resources and a transmission power less than the determined primary maximum transmission power.

1. Field of the Invention
The present invention relates to Peer to Peer (P2P) communication between terminals without a base station. More particularly, the present invention relates to an apparatus and method for allocating frequency resources to perform P2P communication between terminals.
2. Description of the Related Art
In general, methods of allocating frequency resources so as to perform Peer to Peer (P2P) communication are classified into two categories. The first is a method of allocating frequency resources that are the same as those used by a base station and terminals to perform communication between terminals. The second is a method of allocating dedicated frequency resources that are different from those used for cellular communication.
When different frequency resources are allocated for use during P2P communication as compared to the resources used during cellular communication, the hardware and communication resources used to perform the P2P communication between terminals are different from those used to perform cellular communication. For example, if the cellular communication uses frequency resources and hardware for second Generation (2G) and third Generation (3G) communications, and the P2P communication uses other frequency resources and hardware such as ZigBee, WiFi, Bluetooth, etc., dual mode hardware must be implemented in order to perform both the P2P communication and the cellular communication in the same device. The implementation of dual mode hardware increases the device complexity and price. Furthermore, the overall performance of P2P communication devices is lower than that of cellular communication devices, making it difficult to obtain a satisfactory P2P communication transmission rate.
On the other hand, if the same frequency resources are allocated for both the P2P communication and the cellular communication, some of the cellular frequency resources must be allocated as frequency resources for the P2P communication. In this case, since providers cannot use all of the frequency resources for cellular communication, if providers fail to establish a sufficient business model for the P2P communication, it is likely that providers will not prefer to allocate frequency resources for P2P communication. Also, user communication charges for the P2P communication may increase.

Apparatus and method for determining resources for peer to peer communication in communication system


A dual emitting device includes a transparent substrate and an array of pixels. The array of pixels is disposed on the transparent substrate, and each pixel of the array includes at least one first sub-pixel and at least one second sub-pixel. The first sub-pixel includes a first OLED driven by a first TFT, and a first sheltering layer on the first OLED. The second sub-pixel includes a second OLED driven by a second TFT, and a second sheltering layer formed between the transparent substrate and the second OLED.

(1) Field of the Invention
The invention relates to a dual emitting device with an organic electroluminescent structure.
(2) Description of the Prior Art
As more and more various electric products come out, the function of a dual display becomes a main feature of the modern electric products. For example, the dual emitting device installed in a mobile phone can display a main function menu at one side, and display time at the other side. A conventional dual emitting device usually includes two adhered single-side panels, such as a liquid crystal panel adhered to an organic electro-luminescent panel, two adhered liquid crystal panels, or two adhered organic electro-luminescent panels.
FIG. 1 shows a conventional dual emitting device. The conventional dual emitting device 10 includes a first display panel 11 and a second display panel 12. The first display panel 11 has a transparent substrate 111, a first electrode 112, an emission layer 113, a second electrode 114 and a package lid 115. The emission layer 113 is disposed between the first electrode 112 and the second electrode 114. The first electrode 112 is formed on the transparent substrate 111. The package lid 115 is adhered on the transparent panel 111. The second display panel 12 has a transparent substrate 121, a third electrode 122, an emission layer 123, a forth electrode 124 and a package lid 125. The emission layer 123 is disposed between the third electrode 122 and the forth electrode 124. The third electrode 122 is formed on the transparent panel 121. The package lid 125 is adhered on the transparent substrate 121. The package lid 115 is adhered to the package lid 125 to construct the dual emitting device 10.
As stated above, the conventional dual emitting device 10 has two package lids 115 and 125, and two transparent substrates 111 and 121. Therefore, it becomes larger, thicker, and heavier, so as not to meet the requirement of weight, thickness and size. Besides, the two display panels 11 and 12 are respectively manufactured in two different processes. Therefore, the manufacture of the conventional dual emitting device 10 is complicated and time-consuming. Another drawback is that the two display panels 11 and 12 need to be driven independently.
It is difficult to reduce the thickness of the conventional dual emitting device because of the complicated manufacturing process and more package lids and substrates. Therefore, it is desirable to provide an organic electro-luminescent panel and manufacturing process thereof to avoid above disadvantages associated with conventional dual emitting devices.

System and method for differentiating pictures and texts


Extrusion mandrel assembly for continuous extrusion apparatus has a lobed, mushroom shaped, dolly formed with a central spacing stem located in the chamber adjacent a pair of discharge ports connecting respective exit apertures into an internal cavity in the chamber and a pair of shaped lobes having rear faces extending from central spacing stem, outer edge portions and front faces merging into a collar around a neck co-acting with an annular shoulder on extrusion die body to form an annular extrusion gap, with each lobe profiled so frictional surface drag on extruding material is uniform around lobed dolly. Individual paths between discharge ports and annular extrusion gap are equal in length as measured on respective surfaces of the rear faces, edge portions and front faces of profiled lobes. An extruded aluminium cylindrical tube up to 150 mm diameter and wall thickness of 1 mm to 4 mm may be formed avoiding discontinuities.

In WO 90/14176 there is described continuous extrusion apparatus having a plurality of spaced apart circumferential grooves, arcuate tooling with a shoe portion bounding radially outer portions of the respective grooves provided with exit apertures extending in a generally radial direction from the respective grooves to a chamber and abutments displaced in the direction of rotation from the exit apertures extending into the grooves, the chamber extending around an extrusion mandrel assembly and the exit apertures discharging axially of the extrusion mandrel assembly through a die orifice intermediate the extrusion mandrel assembly and an extrusion die body wall.


It has been determined that a fuel delivery system with a fuel supply line and electromagnetically actuatable fuel injection valves produce fuel oscillations during opening and closing of the fuel injection valves and therefore generates noise, which is transmitted into the passenger compartment of the vehicle and annoys the passengers. In order to damp this kind of noise, at least one elongated, hollow damping body is connected at right angles to the fuel supply line and has a closed end. The axial length of the hollow damping body corresponds to 11/2 times the wavelength of the fuel oscillation to be damped in the fuel supply line. The length of the at least one damping body can also correspond to 11/2 times the wavelength of the fuel oscillation to be damped in the fuel supply line, divided by 2 or by a multiple of 2. The fuel delivery system is particularly suited for mixture compressing internal combustion engines with externally supplied ignition.

The invention is based on a fuel delivery system for a vehicle. In fuel delivery systems of this kind, the rapid opening and closing of the electromagnetically actuated fuel injection valves leads to oscillations in the fuel pump of the fuel injection system and leads to an annoying hammering noise which is transmitted into the passenger compartment of a vehicle. In air inlet systems for internal combustion engines, an already known strategy is to produce standing waves in order to damp the air oscillations produced by the engine, which likewise lead to unpleasant noise in the passenger compartment of the vehicle (EP 0 653 020 B1). A device of this kind, however, is not suitable for installation in a fuel delivery system.


A process for the liquid-phase carbonylation of ethylene, according to the equation C2H4+CO+ROHxe2x86x92C2H5CO2R, in the presence of a catalyst system comprising a Group VIII metal or compound thereof, a phosphine ligand and a source of anions, and in the presence of water or a source of organic hydroxyl groups, is carried out in conditions in which the molar ratio of ethylene to carbon monoxide in the gaseous phase of the reactor is greater than 1:1. The higher ratios of ethylene to carbon monoxide are beneficial in increasing the turnover number of the catalyst system.

The invention relates to the carbonylation of ethylene using carbon monoxide.
The carbonylation of ethylene using carbon monoxide in the presence of an alcohol or water and a catalyst system comprising a Group VIII metal, e.g. palladium, and a phosphine ligand, e.g. an alkyl phosphine, cycloalkyl phosphine, aryl phosphine, pyridyl phosphine or bidentate phosphine, has been described in numerous European patents and patent applications, e.g. EP-A-0055875, EP-A-04489472, EP-A-0106379, EP-A-0235864, EP-A-0274795, EP-A-0499329, EP-A-0386833, EP-A-0441447, EP-A-0489472, EP-A-0282142, EP-A-0227160, EP-A-0495547 and EP-A-0495548. In particular, EP-A-0227160, EP-A-0495547 and EP-A-0495548 disclose that bidentate phosphine ligands provide catalyst systems which enable higher reaction rates to be achieved.
A problem with the previously disclosed catalyst systems is that, although relatively high reaction rates can be achieved, the catalyst dies off quickly which necessitates the frequent replenishment of the catalyst and hence results in a process which is industrially unattractive.
WO 96/19434 discloses a particular group of bidentate phosphine compounds which can provide remarkably stable catalysts which require little or no replenishment and the use of such bidentate catalysts in a process for the carbonylation of ethylene with carbon monoxide.
It has now been found that, when used in the process for the carbonylation of ethylene with carbon monoxide, the activity and life of catalyst systems based on such phosphine compounds are very sensitive to the relative amounts of ethylene and carbon monoxide in the gaseous phase of the reactor. This is counter to the common teaching in the art which generally does not express any preference for the relative amounts of these reactants.
Surprisingly therefore, it has now been found that the activity and the life of the catalyst, when used in a liquid phase carbonylation process, can be significantly improved by using a high molar ratio of ethylene to carbon monoxide in the gas in contact with the liquid phase.
Accordingly, the present invention provides a process for the carbonylation of ethylene in a liquid phase, which process comprises
(i) forming a gaseous phase from an ethylene feed stream and a carbon monoxide feed stream;
(ii) contacting the gaseous phase with a catalyst system within the liquid phase containing a source of hydroxyl groups, said catalyst system comprising palladium, or a compound thereof, and a phosphine ligand together with a source of anions; and
(iii) reacting the ethylene with the carbon monoxide in the presence of the source of hydroxyl groups and of the catalyst system
characterised in that the ethylene feed stream and carbon monoxide feed stream provide a molar ratio of ethylene to carbon monoxide in the gaseous phase which is greater than 1:1.
The carbon monoxide may be used in the presence of other gases which are inert in the reaction. Examples of such gases include hydrogen, nitrogen, carbon dioxide and the noble gases such as argon.
The molar ratio of the ethylene to carbon monoxide in the gaseous phase, hereinafter termed the gaseous phase molar ratio, is greater than 1:1, preferably at least 3:1, particularly at least 5:1, especially from 5:1 to 50:1 and particularly especially from 7:1 to 15:1. Operating the process of the present invention with a gaseous phase molar ratio of less than 5:1, particularly of less than 3:1 and especially of less than 1:1 leads to a rapid deterioration in the performance of the catalyst.
It is believed that an important factor that influences the life of the catalyst system is the molar ratio of ethylene to carbon monoxide dissolved in the liquid phase, herein after termed the liquid phase molar ratio. The liquid phase molar ratio may differ from the gaseous phase molar ratio due to the different solubilities of ethylene and carbon monoxide in the liquid phase. The solubilities of ethylene and carbon monoxide in the liquid phase are dependent on factors such as the temperature, pressure and composition of the liquid phase. Consequently, in order to achieve the required liquid phase molar ratio, the gaseous phase molar ratio may need to be adjusted to compensate for such factors. Preferably, the gaseous phase molar ratio should be adjusted such that a liquid phase molar ratio of at least 5:1 is maintained.
The ratio of the number of moles of ethylene to the number of moles of carbon monoxide fed to the reactor by the ethylene feed stream and carbon monoxide feed stream in order to maintain the desired molar ratio of ethylene to carbon monoxide in the gaseous phase will depend on the reactor design. Where the gaseous phase is recycled after contact with the liquid phase then the ethylene and carbon monoxide feed streams are used to replenish the ethylene and carbon monoxide consumed during the carbonylation reaction and the ethylene and carbon monoxide that is removed with any offtake from the liquid phase. Thus, the ratio of the number of moles of ethylene to the number of moles of carbon monoxide fed by the feed streams is approximately 1:1. Alternatively, where the gaseous phase is not fully recycled then the ratio of the number of moles of ethylene to the number of moles of carbon monoxide fed by the feed streams will more closely match the desired molar ratio in the gaseous phase.
The feeds of ethylene and carbon monoxide may be continuous, intermittent or batch. Preferably, the initial feed into the reactor is of ethylene. This further reduces the poisoning of the catalyst system by the carbon monoxide.
The process of the present invention is preferably carried out at a temperature from 20 to 250xc2x0 C., in particular from 40 to 150xc2x0 C. and especially from 70 to 120xc2x0 C.
The process may be conducted under a total pressure of from 1xc3x97105 to 100xc3x97105 N.mxe2x88x922 and in particular from 5xc3x97105to 50xc3x97105 N.mxe2x88x922.
A preferred phosphine ligand is a bidentate phosphine of general formula (I)
wherein
R0 is a tertiary carbon atom each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12 is independently a pendant optionally substituted organic group which carries a carbon atom through which the group is linked to the respective R0;
each of L1 and L2 is independently a linking group selected from an optionally substituted lower alkylene chain connecting the respective phosphorus atom to the group X; and
X is a bridging group comprising an optionally substituted aryl moiety to which the phosphorus atoms are linked on available adjacent carbon atoms.
The pendant optionally substituted organic groups of the preferred catalyst system, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10 and R11 and R12 may be independently selected from a wide range of components. Preferably, the pendant groups are optionally substituted lower alkyl, e.g. C1-8, and may be branched or linear.
Particularly preferred is when the organic groups, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12 when associated with their respective R0 carbon atom, form composite groups which are at least as sterically hindering as t-butyl. Steric hindrance in this context is as discussed at page 14 et seq of xe2x80x9cHomogeneous Transition Metal Catalysisxe2x80x94A Gentle Artxe2x80x9d, by C Masters, published by Chapman and Hall, 1981.
The linking groups, L1 and L2, are independently selected from an optionally substituted, particularly lower alkylor lower alkylene, e.g. C1 to C4, chain. Especially preferred is when both L1 and L2 are methylene.
The bridging group X is an aryl moiety, e.g. a phenyl group, which may be optionally substituted, provided that the two phosphorus atoms are linked to adjacent carbon atoms, e.g. at the 1 and 2 positions on the phenyl group. Optional substitution of the aryl moiety may be by other organic groups, e.g. alkyl, particularly C1-8, aryl, alkoxy, carbalkoxy, halo, nitro, trihalomethyl and cyano. Furthermore, the aryl moiety may be a fused polycyclic group, e.g. naphthalene, biphenylene or indene.
Examples of suitable bidentate ligands are xcex1,xcex1xe2x80x2-bis(di-t-butyl phosphino)-o-xylene (also known as 1,2-bis(di-t-butylphosphinomethyl)benzene), xcex1,xcex1xe2x80x2-bis(dineopentyl phosphino)-o-xylene and 2,3-bis(di-t-butylphosphinomethyl)naphthalene. Additionally, the bidentate phosphine may be bonded to a suitable polymeric or inorganic substrate via at least one of the bridging group X, the linking group L1 or the linking group L2, e.g. xcex1,xcex1xe2x80x2-bis(di-t-butyl phosphino)-o-xylene may be bonded via the xylene group to polystyrene to give an immobile heterogeneous catalyst.
Preferably, the bidentate ligand is present in an amount such that the ratio of the number of moles of the bidentate ligand present to the number of moles of palladium present is from 1 to 50, e.g. 1 to 10 and particularly from 1 to 5 mol per mol.
Suitable compounds of palladium include salts of palladium with, or compounds comprising weakly co-ordinated anions derived from, nitric acid; sulphuric acid; lower alkanoic (up to C12) acids such as acetic acid and propionic acid including halogenated carboxylic acids such as trifluoroacetic acid and trichloroacetic acid; sulfonic acids such as methanesulfonic acid, chlorosulfonic acid, fluorosulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, naphthalene sulfonic acid, toluenesulfonic acids, e.g. p-toluenesulfonic acid, t-butylsulfonic acid, and 2-hydroxypropanesulfonic acid; sulfonated ion exchange resins; perhalic acids such as perchloric acid; halogenated carboxylic acids such as trichloroacetic acid and trifluoroacetic acid; orthophosphoric acid; phosphonic acids such as benzenephosphonic acid; and acids derived from interactions between Lewis acids and Broensted acids. Other sources which may provide suitable anions include the optionally halogenated tetraphenyl borate derivatives, e.g. perfluorotetraphenyl borate. Additionally, zero-valent palladium complexes particularly those with labile ligands, e.g. triphenylphosphine or alkenes such as dibenzylideneacetone or styrene may be used.
The anion may be introduced as one or more of an acid having a pKa measured in aqueous solution of less than 4, a salt with a cation that does not interfere with the reaction, e.g. metal salts or largely organic salts such as alkyl ammonium, and a precursor, such as an ester, that can break down under reaction conditions to generate the anion in situ. Suitable acids and salts include the acids and salts, other than unsubstituted carboxylates, listed supra.
The quantity of anion present is not critical to the catalytic behaviour of the catalyst system. The molar ratio of anion to palladium may be from 1:1 to 500:1, preferably from 2:1 to 100:1 and particularly from 3:1 to 30:1. Where the anion is provided by a combination of acid and salt, the relative proportion of the acid and salt is not critical.
The catalyst system may be used homogeneously or heterogeneously. Preferably the catalyst system is used homogeneously.
The catalyst system is preferably constituted in the liquid phase which may be formed by one or more of the reactants or by the use of a suitable solvent.
Suitable solvents that may be used in conjunction with the catalyst system include one or more aprotic solvents such as ethers, e.g. diethyl ether, dimethyl ether of diethylene glycol, anisole and diphenyl ether, aromatic compounds, including halo variants of such compounds, e.g. benzene, toluene, ethyl benzene, o-xylene, m-xylene, p-xylene, chlorobenzene, odichlorobenzene, mdichlorobenzene, and p-dichlorobenzene; alkanes, including halo variants of such compounds, e.g. hexane, heptane, 2,2,3-trimethylpentane, methylene chloride and carbon tetrachloride; nitriles, e.g. benzonitrile and acetonitrile; esters, e.g. methyl benzoate, methyl acetate, methyl propionate and dimethyl phthalate; sulfones, e.g. diethyl sutfone and tetrahydrothiophene 1,1- dioxide; carboxylic acids, e.g. propionic acid It is preferred to use as a solvent a compound which takes part in the reaction either as a reactant or a product, to minimise the number of different compounds present in the liquid phase to facilitate separation of the mixture. Therefore in the example when ethylene and carbon monoxide are carbonylated in the presence of methanol to form methyl propionate, a particularly suitable solvent is methyl propionate.
The end product of the reaction is determined at least in part by the source of hydroxyl groups that is used. The use of water gives rise to the corresponding carboxylic acid whereas the use of an alkanol leads to the corresponding ester. Suitable alkanofs include C1-30 alkanols, optionally substituted with one or more substituents such as halogen atoms, cyano, carbonyl, alkoxy or aryl groups. Suitable alkanois include one or more of methanol, ethanol, propanol, 2-propanol, 2-butanol, t-butyl alcohol and chlorocapryl alcohol. Particularly useful are methanol and ethanol. Additionally or alternatively, polyhydroxyl compounds, such as diols and sugars, may be used.
The molar ratio of the amount of ethylene used in the reaction to the amount of hydroxyl providing compound is not critical and may vary between wide limits, e.g. from 0.001:1 to 100:1 mol/mol in the liquid phase.
The process of the invention is particularly suitable for the production of methyl propionate. In one preferred embodiment therefore we provide a process for the production of methyl propionate comprising the steps of
(i) forming a gaseous phase from an ethylene feed stream and a carbon monoxide feed stream;
(ii) contacting the gaseous phase with a catalyst system within a liquid phase comprising methanol, a solvent and a catalyst system comprising palladium, or a compound thereof, a phosphine ligand and a source of anions; and
(iii) reacting the ethylene with the carbon monoxide in the presence of the methanol and of the catalyst system;
characterised in that the ethylene feed stream and carbon monoxide feed stream provide a molar ratio of ethylene to carbon monoxide in the gaseous phase which is greater than 1:1.
Preferred catalyst systems are those described above. Preferably the solvent comprises methanol, methyl propionate or a mixture thereof.

Process for the palladium and phosphine ligand catalyzed carbonylation of ethylene


A back support apparatus includes a pair of shoulder straps and a pair of heel connectors interconnected by a pair of support lines each with a resilient section, and further includes a cover pad with a belt for coupling around the user's waist and for positioning the pad over the user's lower back. In preferred forms, the apparatus includes a pair of spaced tubular guides coupled with the pad for guiding the support lines.

1. Field of the Invention
The present invention is concerned with the field of back supports as an aid in performing manual labor requiring frequent bending from the waist. More particularly, the invention is concerned with a back support apparatus including a pair of shoulder straps and a pair of heel connectors interconnected by a pair of support lines each with a resilient section.
2. Description of the Prior Art
Some types of manual labor require frequent bending from the waist such as picking crops. This type of labor is particularly stressful on the back muscles sometimes leading to permanent injury.
In the prior art, various devices have been developed for supporting the back during activities requiring frequent bending from the waist. In general, these prior art devices have not been as effective as needed and tend to be mechanically complex or unreliable in use. Accordingly, the prior art points out the need for an improved back support apparatus.