A method for detecting the presence of a target nucleic acid sequence in a sample, said method comprising:

The present invention provides a method for detecting a target polynucleotide in a sample, for example by quantitatively monitoring an amplification reaction, as well as to probes and kits for use in these methods. The method is particularly suitable for the detection of polymorphisms or allelic variation and so may be used in diagnostic methods
Known fluorescence polymerase chain reaction (PCR) monitoring techniques include both strand specific and generic DNA intercalator techniques that can be used on a few second-generation PCR thermal cycling devices.
Generic methods utilise DNA intercalating dyes that exhibit increased fluorescence when bound to double stranded DNA species. Fluorescence increase due to a rise in the bulk concentration of DNA during amplifications can be used to measure reaction progress and to determine the target molecule copy number. Furthermore, by monitoring fluorescence with a controlled change of temperature, DNA melting curves can be generated, for example, at the end of PCR thermal cycling.
When generic DNA methods are used to monitor the rise in bulk concentration of nucleic acids, these processes can be monitored with a minimal time penalty (compared to some other known assays discussed below). A single fluorescent reading can be taken at the same point in every reaction. End point melting curve analysis can be used to discriminate artifacts from amplicon, and to discriminate amplicons. Melting peaks of products can be determined for concentrations that cannot be visualized by agarose gel electrophoresis.
In order to obtain high resolution melting data, for example for multiple samples, the melt experiment must be performed slowly on existing hardware taking up to five minutes. However, by continually monitoring fluorescence amplification, a 3D image of the hysteresis of melting and hybridization can be produced. This 3D image is amplicon dependent and may provide enough information for product discrimination.
It has been found that DNA melting curve analysis in general is a powerful tool in optimizing PCR thermal cycling. By determining the melting temperatures of the amplicons, it is possible to lower the denaturing temperature in later PCR cycles to this temperature. Optimization for amplification from first generation reaction products rather than the target DNA, reduces artifact formation occurring in later cycles. Melting temperatures of primer oligonucleotides and their complements can be used to determine their annealing temperatures, reducing the need for empirical optimization.
The generic intercalator methods however are only quasi-strand-specific and therefore is not very useful where strand specific detection is required.
Strand specific methods utilise additional nucleic acid reaction components to monitor the progress of amplification reactions. These methods often use fluorescence energy transfer (FET) as the basis of detection. One or more nucleic acid probes are labeled with fluorescent molecules, one of which is able to act as an energy donor and the other of which is an energy acceptor molecule. These are sometimes known as a reporter molecule and a quencher molecule respectively. The donor molecule is excited with a specific wavelength of light which falls within its excitation spectrum and subsequently it will emit light within its fluorescence emission wavelength. The acceptor molecule is also excited at this wavelength by accepting energy from the donor molecule by a variety of distance-dependent energy transfer mechanisms. A specific example of fluorescence energy transfer which can occur is Fluorescence Resonance Energy Transfer or xe2x80x9cFRETxe2x80x9d. Generally, the acceptor molecule accepts the emission energy of the donor molecule when they are in close proximity (e.g. on the same, or a neighboring molecule). The basis of fluorescence energy transfer detection is to monitor the changes at donor and acceptor emission wavelengths.
There are two commonly used types of FET or FRET probes, those using hydrolysis of nucleic acid probes to separate donor from acceptor, and those using hybridization to alter the spatial relationship of donor and acceptor molecules.
Hydrolysis probes are commercially available as Taqman(trademark) probes. These consist of DNA oligonucleotides that are labeled with donor and acceptor molecules. The probes are designed to bind to a specific region on one strand of a PCR product. Following annealing of the PCR primer to this strand, Taq enzyme extends the DNA with 5xe2x80x2 to 3xe2x80x2 polymerase activity. Taq enzyme also exhibits 5xe2x80x2 to 3xe2x80x2 exonuclease activity. TaqMan(trademark) probes are protected at the 3xe2x80x2 end by phosphorylation to prevent them from extension. If the TaqMan(trademark) probe is hybridized to the product strand, an extending Taq molecule may also hydrolyze the probe, liberating the donor from acceptor as the basis of detection. The signal in this instance is cumulative, the concentration of free donor and acceptor molecules increasing with each cycle of the amplification reaction.
The fact that signal generation is dependent upon the occurrence of probe hydrolysis reactions means that there is a time penalty associated with this method. Furthermore, the presence of the probe may interrupt the smooth operation of the PCR process.
In addition, it has been found that hydrolysis can become non-specific, particularly where large numbers of amplification cycles, for instance more than 50 cycles, are required. In these cases, non-specific hydrolysis of the probe will result in an unduly elevated signal.
This means that such techniques are not very compatible with rapid PCR methods which are becoming more prominent with the development of rapid hot air thermal cyclers such as the RapidCycler(trademark) and LightCycler(trademark) from Idaho Technologies Inc. Other rapid PCR devices are described for example in co-pending British Patent Application Nos. 9625442.0 and 9716052.7. The merits of rapid cycling over conventional thermal cycling have been reported elsewhere. Such techniques are particularly useful for example in detection systems for biological warfare where speed of result is important if loss of life or serious injury is to be avoided.
Furthermore, hydrolysis probes do not provide significant information with regard to hysteresis of melting since signal generation is, by and large, dependent upon hydrolysis of the probe rather than the melt temperature of the amplicon.
U.S. Pat. No. 5,491,063 describes a method for in-solution quenching of fluorescently labeled probes which relies on modification of the signal from a labeled single stranded oligonucleotide by a DNA binding agent. The difference in this signal which occurs as a result of a reduced chain length of the probe following probe cleavage (hydrolysis) during a polymerase chain reaction is suggested for providing a means for detecting the presence of a target nucleic acid.
Hybridization probes are available in a number of forms. Molecular beacons are oligonucleotides that have complementary 5xe2x80x2 and 3xe2x80x2 sequences such that they form hairpin loops. Terminal fluorescent labels are in close proximity for FRET to occur when the hairpin structure is formed. Following hybridization of molecular beacons to a complementary sequence the fluorescent labels are separated, so FRET does not occur, and this forms the basis of detection.
Pairs of labeled oligonucleotides may also be used. These hybridize in close proximity on a PCR product strand bringing donor and acceptor molecules together so that FRET can occur. Enhanced FRET is the basis of detection. Variants of this type include using a labeled amplification primer with a single adjacent probe.
The use of two probes, or a molecular beacon type of probe which includes two labeling molecules increases the cost involved in the process. In addition, this method requires the presence of a reasonably long known sequence so that two probes which are long enough to bind specifically in close proximity to each other are known. This can be a problem in some diagnostic applications, where the length of conserved sequences in an organism which can be used to design an effective probe, such as the HIV virus, may be relatively short.
Furthermore, the use of pairs of probes involves more complex experimental design. For example, a signal provided when by the melt of a probe is a function of the melting off of both probes. The study of small mismatches or where one of the probes is required to bind across a splice region (for example to detect RNA as compared to DNA in a sample where the sequence on either side of an intron can be utilised as the probe site) can yield incorrect results if the other probe melts first.
U.S. Pat. No. 4,868,103 describes in general terms, a FRET system for detecting the presence of an analyte, which utilises an intercalating dye as the donor molecule. The process does not involve an amplification stage.
The applicants have developed a strand specific system for detecting the presence of particular nucleic acid sequences.
The invention provides a method for detecting the presence of a target nucleic acid sequence in a sample, said method comprising:
(a) adding to a sample suspected of containing said target nucleic acid sequence, a DNA duplex binding agent, and a probe specific for said target sequence, said probe comprising a reactive molecule able to absorb fluorescence from or donate fluorescent energy to said DNA duplex binding agent,
(b)subjecting the thus formed mixture to an amplification reaction in which target nucleic acid is amplified,
(c) subjecting said sample to conditions under which the said probe hybridizes to the target sequence, and
(d)monitoring fluorescence from said sample.
As used herein, the expression xe2x80x9cDNA duplex binding agentxe2x80x9d refers to any entity which adheres or associates itself with DNA in duplex form. These include intercalating dyes as are well known in the art.
As the probe hybridizes to the target sequence in step (c), DNA duplex binding agent such as an intercalating dye is trapped between the strands. In general, this would increase the fluorescence at the wavelength associated with the dye. However, where the reactive molecule is able to absorb fluorescence from the dye (i.e. it is an acceptor molecule), it accepts emission energy from the dye by means of FET, especially FRET, and so it emits fluorescence at its characteristic wavelength. Increase in fluorescence from the acceptor molecule, which is of a different wavelength to that of the dye, will indicate binding of the probe in duplex form. Thus changes in fluorescence which are indicative of the formation or destabilization of duplexes involving the probe are preferably monitored in step (d).
Similarly, where the reactive molecule is able to donate fluorescence to the dye (i.e. it is a donor molecule), the emission from the donor molecule is reduced as a result of FRET and this reduction may be detected. Fluorescence of the dye is increased more than would be expected under these circumstances.
Preferably the reactive molecule is an acceptor molecule as the signals are more readily determinable.
The use of a DNA duplex binding agent such as an intercalating dye and a probe which is singly labeled is advantageous in that these components are much more economical than other assays in which doubly labeled probes are required. By using only one probe, the length of known sequence necessary to form the basis of the probe can be relatively short and therefore the method can be used, even in difficult diagnostic situations.
Furthermore the method of the invention is extremely versatile in its applications. The method can be used to generate both quantitative and qualitative data regarding the target nucleic acid sequence in the sample, as discussed in more detail hereinafter. In particular, not only does the invention provide for quantitative amplification, but also it can be used, additionally or alternatively, to obtain characterizing data such as duplex destabilization temperatures or melting points.
In the method of the invention, the sample may be subjected to conditions under which the probe hybridizes to the samples during or after the amplification reaction has been completed. The process therefore allows the detection to be effected in a homogenous manner, in that the amplification and monitoring can be carried out in a single container with all reagents added initially. No subsequent reagent addition steps are required. Neither is there any need to effect the method in the presence of solid supports (although this is an option).
The probe may comprise a nucleic acid molecule such as DNA or RNA, which will hybridize to the target nucleic acid sequence when the latter is in single stranded form. In this instance, step (c) will involve the use of conditions which render the target nucleic acid single stranded.
Probe may either be free in solution or immobilized on a solid support, for example to the surface of a bead such as a magnetic bead, useful in separating products, or the surface of a detector device, such as the waveguide of a surface plasmon resonance detector. The selection will depend upon the nature of the particular assay being looked at and the particular detection means being employed.
In particular, the amplification reaction used will involve a step of subjecting the sample to conditions under which any of the target nucleic acid sequence present in the sample becomes single stranded. Such amplification reactions include the polymerase chain reaction (PCR) or the ligase chain reaction (LCR) but is preferably a PCR reaction.
It is possible then for the probe to hybridize during the course of the amplification reaction provided appropriate hybridization conditions are encountered.
In a preferred embodiment, the probe may be designed such that these conditions are met during each cycle of the amplification reaction. Thus at some point during each cycle of the amplification reaction, the probe will hybridize to the target sequence, and generate a signal as a result of the FET or FRET between it and the DNA duplex binding agent such as the intercalating dye trapped between the probe and the target sequence. As the amplification proceeds, the probe will be separated or melted from the target sequence and so the signal generated by it will reduce. Hence in each cycle of the amplification, a fluorescence peak from the reactive molecule is generated. The intensity of the peak will increase as the amplification proceeds because more target sequence becomes available for binding to the probe.
By monitoring the fluorescence of the reactive molecule from the sample during each cycle, the progress of the amplification reaction can be monitored in various ways. For example, the data provided by melting peaks can be analyzed, for example by calculating the area under the melting peaks and this data plotted against the number of cycles.
For example, the fluorescence is suitably monitored using a known fluorimeter. The signals from these, for instance in the form of photo-multiplier voltages, are sent to a data processor board and converted into a spectrum associated with each sample tube. Multiple tubes, for example 96 tubes, can be assessed at the same time. Data may be collected in this way at frequent intervals, for example once every 10 ms, throughout the reaction.
The spectra generated in this way can be resolved, for example, using xe2x80x9cfitsxe2x80x9d of pre-selected dyes, to form peaks representative of each signaling moiety (i.e. dye and/or reactive molecule). The areas under the peaks can be determined which represents the intensity value for each signal, and if required, expressed as quotients of each other. The differential of signal intensities and/or ratios will allow changes in FRET to be recorded through the reaction or at different reaction conditions, such as temperatures. The changes, as outlined above, are related to the binding phenomenon between the probe and the target sequence. The integral of the area under the differential peaks will allow intensity values for the FRET effects to be calculated.
This data provides the opportunity to quantitate the amount of target nucleic acid present in the sample.
In addition, the kinetics of probe hybridization will allow the determination, in absolute terms, of the target sequence concentration. Changes in fluorescence from the sample can allow the rate of hybridization of the probe to the sample to be calculated. An increase in the rate of hybridization will relate to the amount of target sequence present in the sample. As the concentration of the target sequence increases as the amplification reaction proceeds, hybridization of the probe will occur more rapidly. Thus this parameter also can be used as a basis for quantification. This mode of data processing useful in that it is not reliant on signal intensity to provide the information.
Preferably, the fluorescence of both the dye and the reactive molecule are monitored and the relationship between the emissions calculated. This provides a strand specific measure to complement the generic DNA information provided by measuring fluorescence from the dye. In this way, the contribution to the signal of non-specific amplification can be distinguished and thus the method provides an internal check.
Suitable reactive molecules are rhodamine dyes or other dyes such as Cy5 or fluorescein. These may be attached to the probe in a conventional manner. The position of the reactive molecule along the probe is immaterial although it general, they will be positioned at an end region of the probe.
Intercalating dyes are well known in the art. They include for example SYBRGreen such as SYBRGreen I, SYBRGold, ethidium bromide and YOPRO-1.
In order for FET, such as FRET, to occur between the reactive molecule and the dye, the fluorescent emission of the donor (which may either be the intercalating dye or the reactive molecule on the probe) must be of a shorter wavelength than the acceptor (i.e. the other of the dye or the reactive molecule).
Preferably, the molecules used as donor and/or acceptor produce sharp peaks, and there is little or no overlap in the wavelengths of the emission. Under these circumstances, it may not be necessary to resolve the strand specific peak from the DNA duplex binding agent signal. A simple measurement of the strand specific signal alone (i.e. that provided by the reactive molecule) will provide information regarding the extent of the FRET caused by the target reaction. The ethidium bromide/fluorescein combination may fulfil this requirement. In that case, the strand specific reaction will be quantifiable by the reduction in fluorescence at 520 nm, suitably expressed as 1/Fluorescence.
However, where there is a spectral overlap in the fluorescent signals from the donor and acceptor molecules, this can be accounted for in the results, for example by determining empirically the relationship between the spectra and using this relationship to normalize the signals from the two signals.
It is possible to design the probe such that it is hydrolyzed by the DNA polymerase used in the amplification reaction thereby releasing the reactive molecule. This provides a cumulative signal, with the amount of free reactive molecule present in the system increasing with each cycle. A cumulative signal of this type may be particularly preferred where the amount of target sequence is to be quantified. However, it is not necessary in this assay for the probe to be consumed in this way as the signal does not depend solely upon the dissociation of the probe.
In order to achieve a fully reversible signal which is directly related to the amount of amplification product present at each stage of the reaction, and/or where speed of reaction is of the greatest importance, for example in rapid PCR, it is preferable that the probe is designed such that it is released intact from the target sequence. This may be, for example, during the extension phase of the amplification reaction. However, since the signal is not dependent upon probe hydrolysis, the probe may be designed to hybridize and melt from the target sequence at any stage during the amplification cycle, including the annealing or melt phase of the reaction. Such probes will ensure that interference with the amplification reaction is minimized.
Where probes which bind during the extension phase are used, their release intact from the target sequence can be achieved by using a 5xe2x80x2-3xe2x80x2 exonuclease lacking enzyme such as Stoffle fragment of Taq or Pwo.
In order to ensure that the probe is not extended during the extension phase of this, or indeed, any of the amplification reactions, the 3xe2x80x2 end of the probe can be blocked, suitably by phosphorylation.
The probe may then take part again in the reaction, and so represents an economical application of probe.
The data generated in this way can be interpreted in various ways. In its simplest form, an increase in fluorescence of the acceptor molecule in the course of or at the end of the amplification reaction is indicative of an increase in the amount of the target sequence present, suggestive of the fact that the amplification reaction has proceeded and therefore the target sequence was in fact present in the sample. However, as outlined above, quantitation is also possible by monitoring the amplification reaction throughout. In addition, the emissions from the DNA duplex binding agent, in particular the intercalating dye, can be used in order to monitor the bulk rise in nucleic acid in the sample and this can be compared to the strand specific amplification, as measured by the relationship between the reactive molecule and dye signals. Finally, it is possible to obtain characterization data and in particular melting point analysis, either as an end point measure or throughout, in order to obtain information about the sequence as will be discussed further below.
Thus, a preferred embodiment of the invention comprises a method for detecting nucleic acid amplification comprising: performing nucleic acid amplification on a target polynucleotide in the presence of (a) a nucleic acid polymerase (b)at least one primer capable of hybridizing to said target polynucleotide, (c) a fluorescent DNA duplex binding agent and (d) an oligonucleotide probe which is capable of binding to said target polynucleotide sequence and which contains an acceptor molecule which is capable of absorbing fluorescence from the said dye; and monitoring changes in fluorescence during the amplification reaction.
As before, the DNA duplex binding agent is suitably an intercalating dye. The amplification is suitably carried out using a pair of primers which are designed such that only the target nucleotide sequence within a DNA strand is amplified as is well understood in the art. The nucleic acid polymerase is suitably a thermostable polymerase such as Taq polymerase.
Suitable conditions under which the amplification reaction can be carried out are well known in the art. The optimum conditions may be variable in each case depending upon the particular amplicon involved, the nature of the primers used and the enzymes employed. The optimum conditions may be determined in each case by the skilled person. Typical denaturation temperatures are of the order of 95xc2x0 C., typical annealing temperatures are of the order of 55xc2x0 C. and extension temperatures are of the order of 72xc2x0 C.
The method can be used in hybridization assays for determining characteristics of particular sequences.
Thus in a further aspect, the invention provides a method for determining a characteristic of a sequence, said method comprising;
(a)adding to a sample suspected of containing said sequence, DNA duplex binding agent and a probe specific for said target sequence and, said probe comprising a reactive molecule able to absorb fluorescence from or donate fluorescent energy to said DNA duplex binding agent,
(b) subjecting said sample to conditions under which the said probe hybridizes to the target sequence,
(c) monitoring fluorescence from said sample and determining a particular reaction condition, characteristic of said sequence, at which fluorescence changes as a result of the hybridization of the probe to the sample or destabilization of the duplex formed between the probe and the target nucleic acid sequence.
Suitable reaction conditions include temperature, electrochemical, or the response to the presence of particular enzymes or chemicals. By monitoring changes in fluorescence as these properties are varied, information characteristic of the precise nature of the sequence can be achieved. For example, in the case of temperature, the temperature at which the probe separates or xe2x80x9cmeltsxe2x80x9d from the target sequence can be determined. This can be extremely useful in for example, to detect and if desired also to quantitate, polymorphisms in sequences including allelic variation in genetic diagnosis. By xe2x80x9cpolymorphismxe2x80x9d is included transitions, transversions, insertions, deletions of inversions which may occur in sequences, particularly in nature.
The hysteresis of melting of the probe will be different if the target sequence varies by only one base pair. Thus where a sample contains only a single allelic variant, the temperature of melting of the probe will be a particular value which will be different from that found in a sample which contains only another allelic variant. A sample containing both allelic variants which show two melting points corresponding to each of the allelic variants.
Similar considerations apply with respect to electrochemical properties, or in the presence of certain enzymes or chemicals. The probe may be immobilized on a solid surface across which an electrochemical potential may be applied. Target sequence will bind to or be repulsed from the probe at particular electrochemical values depending upon the precise nature of the sequence.
This embodiment can be effected in conjunction with amplification reactions such as the PCR reaction mentioned above, or it may be employed individually. Again, the reactive molecule is preferably an acceptor molecule.
Further aspects of the invention include kits for use in the method of the invention. These kits will contain a probe specific for a target nucleotide sequence which contains a reactive molecule. Additionally, they may contain a DNA duplex binding agent such as an intercalating dye which is compatible in terms of being able to undergo FET or FRET with said reactive molecule. Other potential components of the kit include reagents used in amplification reactions such as DNA polymerase.

Fluorimetric detection system of a nucleic acid

Abstract: (a) adding to a sample suspected of containing said target nucleic acid sequence, a probe specific for said target sequence and DNA duplex binding agent, said probe comprising a reactive molecule able to absorb fluorescence from or donate fluorescent energy to said DNA duplex binding agent,

Abstract: (b) subjecting the thus formed mixture to an amplification reaction in which target nucleic acid is amplified,

Abstract: (d) monitoring fluorescence from said sample.

Abstract: This method can be used for example to monitor amplification reactions such as PCR reactions, such that the amount of target sequence present in the sample may be determined. Additionally or alternatively, it may be used to generate duplex destabilization data such as melt hysteresis information for amplification monitoring or for detection and quantitation of polymorphisms or allelic variation, and so is useful in genetic diagnosis.


Various approaches are disclosed for simultaneously generating optical coherence tomography (OCT) and confocal scanning laser images by spatially separating the signal normally used for OCT imaging with selective reflecting or beam directing devices. In one preferred embodiment, the invention includes a mirror having a central transmission region, such that the radially outer region of the returning signal beam is reflected and used for generating a confocal image while the central part of the signal beam is transmitted and used to generate an OCT image. In other embodiments, the signals may be spatially separated in other ways, such as with an optic having a reflective center surface, a mirror having two parts oriented at different angles, one or more wedged optics, or a dispersive component. A further aspect of the invention is the ability to increase the frame rate of the confocal imaging.

In optical imaging of biological tissues, especially the living human eye, it has been shown in recent years that both optical coherence tomography (OCT) and confocal scanning laser imaging systems have particular individual advantages.
Confocal scanning laser imaging has been successfully applied to retinal imaging and is now well accepted by ophthalmologists in imaging the anatomic structures of the retina (see for example, Sharp, P. F. et al. (2004). "The scanning laser ophthalmoscope—a review of its role in bioscience and medicine." Physics in Medicine and Biology 49(7): 1085-1096). The depth resolution of a confocal scanning laser ophthalmoscope (CSLO) is determined by the depth of focus of the confocal optics, and as a result, it typically has an axial resolution of approximately 300 microns.
In contrast to CSLO, the axial resolution of OCT is determined by the coherence length of the light source used, and thus can provide a much higher axial imaging resolution—on the order of 10 microns. OCT is particularly useful for diagnostics that require high depth resolution tomographic imaging (Fujimoto, J. G. et al. (2000). "Optical coherence tomography: an emerging technology for biomedical imaging and optical biopsy." Neoplasia 2(1-2): 9-25; Rollins, A. M. et al. (2002). "Emerging clinical applications of optical coherence tomography." Optics and Photonics News 13(4): 36-41; Fujimoto, J. G. (2003). "Optical coherence tomography for ultrahigh resolution in vivo imaging." Nature Biotechnology 21(11): 1361-1367).
Although OCT measures optical reflectivity over a volume of interest, attempts have been made to use the data to produce en-face images that look like the retinal images from an ophthalmoscope (Podoleanu, A. G. et al. (1997). "Simultaneous en-face imaging of two layers in the human retina by low-coherence reflectometry." Optics Letters 22(13): 1039-1041; Podoleanu, A. G. et al. (1998). "En-face coherence imaging using galvanometer scanner modulation." Optics Letters 23(3): 147-149). In principle, OCT can be used to measure optical reflectivity at a dense set of points covering a volume of interest, and then the OCT data can be reduced to simulate the en-face image that would be seen by a CSLO or other ophthalmoscope. In one approach, the OCT signal is used to simultaneously create, in addition to an OCT image, an anatomic structure image with an appearance similar to that of a CSLO image. This can be done by integrating, or superimposing on top of one another, multiple OCT signals along the depth dimension. The result is an en-face image based on the averaged overall depth reflectivity for each transverse pixel (Hitzenberger, C. K. et al. (2003). "Three-dimensional imaging of the human retina by high-speed optical coherence tomography." Optics Express 11(21): 2753-2761). Another approach to generating a CSLO-like image uses multiple light sources of different coherence lengths. This allows simultaneous generation of multiple OCT images of different depth resolutions. Still another approach uses low-pass electronic filtering of the OCT signal to extract a CSLO-like image.
However, these en-face images generated from OCT data have a number of drawbacks. In particular, the image quality is typically inferior to traditional confocal images. OCT collection optics generally collect less of the light returning from the sample than CSLO collection optics. As is well known in the art, OCT is an interference-based technique, so only light that is spatially coherent contributes to the signal. The light returning from the sample is also often collected in a single-mode optical fiber. Reflected light that does not couple into that single mode, either because it falls outside the fiber core or because it enters at too steep an angle, is rejected. Often the vast majority of the light reflected from the sample is rejected in this way. In addition, the frame rate of such en-face images is generally constrained by the speed of the OCT scanning optics.
Given these drawbacks of en-face images generated from OCT data and the different advantages of OCT and CSLO, it is desirable to simultaneously generate both OCT and CSLO images. One of the major benefits of combining OCT and CSLO is that they have different depth ranges. Another is that a 2-D image of the sample generated by CSLO can be used to correctly position the OCT system relative to the sample.
Most designs that have been used to generate both OCT and 2-D images of a sample add an additional optical path to an OCT system to support an independent fundus camera, CSLO, line scanning laser ophthalmoscope (LSLO), or similar imaging modality. Nevertheless, attempts have been made to directly use an OCT configuration to generate both an OCT image and a CSLO image. In one approach, the reference light of an OCT interferometer was alternately temporarily blocked to generate a CSLO signal and restored to generate an OCT signal. However, this approach results in sequential, rather than simultaneous, acquisition of the OCT and CSLO images.
Such a technique, which directly uses the OCT configuration to generate both an OCT image and a CSLO image, collects light for both the OCT and the CSLO images through a small pin-hole defined by the core size of a single-mode fiber. The pinhole is on the order of 10 microns. In contrast, the standard pinhole size in a CSLO system is approximately 100 microns. The numerical aperture (NA) is thus much smaller than in a standard CSLO system, resulting in a lower signal-to-noise ratio for a CSLO image generated with an OCT system. Another problem associated with this approach is that the fiber end can strongly reflect the light returning from the sample. The reflected light can be sent to the confocal detector with a strength greater than the light not reflected from the fiber returning from the sample, causing the CSLO sample signal to be overwhelmed by the fiber end reflection.
A second approach that has been used to generate both OCT and CSLO images is to separate the light returned from the sample into two components using a plate beam-splitter. One of the components is used to generate the OCT image, and the other is directed to a separate pinhole and used to generate a CSLO image. Such a design has some advantages over the alternating generation of OCT and CSLO images described above. Because the light used to generate the CSLO image is directed through a separate pinhole, the size of the pinhole can be chosen to optimize the CSLO signal-to-noise ratio. Further, because the light used to generate the CSLO image is not directed toward the single-mode fiber, the CSLO signal is not overwhelmed by reflection from the fiber end. This approach also allows for simultaneous generation of OCT and CSLO images. Finally, this approach allows the same transverse scanner to be used for both the OCT beam and the CSLO beam. Registration between the OCT and confocal images can be achieved with optical alignment of the respective detectors and the free-space beam splitter.
However, this second approach, too, has significant limitations. Because a portion of the returned sample beam is deflected to the CSLO pinhole, the OCT signal strength is reduced. It also does not maximize the signal to the CSLO detector because the cladding of the OCT single mode fiber absorbs a significant amount of the returned sample beam that could have been used for the CSLO image.
In U.S. Pat. No. 7,382,464, a novel dual-waveguiding module is disclosed for efficient collection and separation of OCT and CSLO signals. The two signals are separated by channeling most of the multi-mode guided optical power to a CSLO detector. The non-tapped single-mode guided optical wave is further sent to a pure single-mode fiber of a standard OCT system for OCT image generation. That invention achieves highly efficient optical power usage and hence high signal to noise ratio, together with inherent pixel-to-pixel registration of the OCT and CSLO images, and a cost reduction of the combined OCT/CSLO system. A specialized fiber optic is required for this approach.
Here we present another approach to generating simultaneous high quality OCT and CSLO images without use of this specialized fiber optic.

Two-dimensional confocal imaging using OCT light source and scan optics


The invention relates to a device for inspecting hollow spaces such as pipes, conduits, structures or containers. The device consists of the following: a probe with a built-in camera (5.0) whose objective is oriented towards a front end of a base body (1.0) of said probe; a hose-type supply line to the probe for a liquid or gaseous medium, said line being connected to the back end of the base body of said probe; a supply unit for the hose-type supply line, which is situated outside of the area where the probe is being used; at least one outlet nozzle (3.0) for the medium, which is located on the probe; and transmission means which are provided between the camera (5.0) and an evaluating and/or reproducing unit. At least three rotating outlet nozzles for the medium are situated on the periphery of the base body (1.0) between its front and back end and the jet axis of the medium is angled at 0xc2x0 to 45xc2x0 from the central longitudinal axis between the front and back end of the base body (1.0).

The invention relates to a device and a method for inspecting hollow spaces having the features recited in the preamble of claim 1.
The DE-C-40 31 715, DE-A-38 03 274, DE-U-91 05 211 and DE-C-42 29 787 disclose methods and devices for inspecting conduits by image transmission that permit to introduce a second camera system into pipes branching from the main pipe using the assistance of a carriage located therein. Nozzles are also known to be used for cleaning sewers in which the outlet openings are arranged in such a manner that they are capable of supplying the thrust necessary to draw along a supply hose. These pipe cleaning nozzles are also known to be used as a driving element for introducing inspection cameras. However, the heretofore known techniques do not permit the inspection of very long lines with small dimensions, the wheel-driven camera being no longer able to pull the cable. In addition, these techniques are not capable of circumventing obstacles and branch lines are still difficult to inspect. Although the above mentioned method, which is directed to introduce second cameras into the branch lines, solves the problem of inspecting such branch lines, it does not allow to overcome obstacles. Furthermore, the expense of technical requirements and staff is increased since two camera systems have to be monitored.
Therefore, it is an object of the present invention to provide a device and a method for inspecting hollow spaces such as conduits and the like that permit to introduce a base member carrying a camera into branch lines and by means of which obstacles may be overcome. It is another object of the invention to make it possible to make for any desired location in large containers or buildings by means of the device according to the invention.
The solution to this object is achieved by the features recited in the characterizing part of claim 1. Developments and advantageous embodiments of the invention are comprised in the other claims.
According to the invention, a device for inspecting hollow spaces such as pipes, conduits, buildings or containers and consisting of a probe with a built-in camera whose objective is oriented toward a front end of a base member of the probe, of a hose line for supplying a liquid or gaseous medium to the probe, said line being connected to the back end of the base member of said probe, of a supply unit for the hose supply line which is situated outside the site of utilization of the probe, of at least one outlet nozzle for the medium which is located on the probe, and of transmission means which are provided between the camera and an evaluating and/or imaging unit, is characterized in that at least three rotatable outlet nozzles for the medium are arranged on the periphery of the base member between its front and back end, the axis of the jet of the medium being angled at an angle of 0xc2x0 to 45xc2x0 from the central longitudinal axis between the front and back end of the base member.
There are preferably provided four rotatable outlet nozzles whose axes of rotation are offset by 90 degrees across the central longitudinal axis of the base member. The outlet nozzles are preferably rotatable 360 degrees and are driven by at least one electric servomotor.
Outside the hollow space to be inspected, a control and feeding cable is arranged between the servomotor and a control unit.
The rotatable outlet nozzles are preferably in the shape of a disk or of a flat cone and are non-rotatably carried on axles that are arranged at right angles. Preferably, the respective outlet openings of the nozzles are arranged on the periphery of the disk or flat cone, respectively.
The axles are preferably devised as hollow axles for the transportation of the medium from the hose supply line to the outlet nozzles and the axes of the jet of the medium exiting the outlet openings are oriented toward the respective one of the central longitudinal axes of the hollow axles.
According to a particular embodiment of the invention, the probe is equipped with a gyrometer. According to other advantageous realizations of the invention, further testing and measuring instruments and/or sensors are arranged, in addition to the camera, in or on the base member.
A method for inspecting hollow spaces such as pipes, conduits, buildings or containers in accordance with the invention involves the following steps:
connecting a probe according to the claims 1 through 11 to a supply unit with a liquid or gaseous medium by means of a hose supply line,
introducing the probe into the hollow space to be inspected,
admitting a pressurized medium into the probe,
controlling the rotatable nozzles by way of the control cable such that the probe is held in the free space on one side and that, on the other side, a recoil force develops, advancing the probe into the respective hollow space and evaluating the results.

Device and method for inspecting hollow spaces


A spray tower (20) for improving contact between a gas stream (22) and a fluid (24). The spray tower (20) includes a tank (26) having an inlet (32) and an outlet (34), and a plurality of spray nozzles (28) positioned in the tank, each of the plurality of spray nozzles including a spray outlet (38). Each of the plurality of spray nozzles (28) is adapted to spray a cone (40) of the fluid (24) through the spray outlet (38) into the tank (26). The spray tower (20) also includes a perforated plate (30) having a plurality of perforations (44). The perforated plate (30) is positioned in the tank (26) so as to define a cross-section of the tank and each of the plurality of perforations (44) is aligned with the cone (40) flowing from the spray outlet (38) of one of the spray nozzles.

(1) Field of the Invention
The present invention generally relates to a spray tower for improving contact between a gas stream and a fluid such as a liquid, slurry, or the like. In particular, the present invention is directed to perforated plate covering a cross-section of the spray tower that is aligned with spray nozzles thereby forcing gas into the dense stream of the fluid.
(2) Description of the Related Art
Generally, open spray towers can be used for heat exchange purposes, for the removal of entrained solids and/or liquids in a gas, or for chemical interchanges. One form of a gas and fluid contact system is used for the removal of acid gases such as sulfur dioxide, hydrogen chloride, hydrogen fluoride from flue gases. Typically, the fluid selected is a fluid of limestone and gypsum, or the like, which is sprayed through multiple levels of spray nozzles, thereby providing contact with the acidic flue gas.
In the case of calcium-based flue gas desulfurization, such as limestone slurry scrubbing, there is a fixed dissolved alkalinity in the sprayed slurry, which is depleted rapidly. After depletion, the drops no longer scrub SO2 or scrub it slowly. Spray nozzles are typically arranged in a manner to cover a portion of the area of the spray tower. A portion of the gas contacts the slurry and reacts. However, there is much gas that only contacts a depleted spray and therefore no, or only a slight reaction, occurs.
Generally, the spray nozzles are arranged so that the sprays overlap to cover a larger area. Still, much of the gas does not contact the spray. One way maldistribution is reduced is by using a custom spray integrated into the tray and support structure or by disturbing stratification at the wall of the absorber. Also, typical practice to improve gas liquid distribution is to stagger nozzle layout, such that nozzles are not in vertical alignment, therefore covering a larger area. However, these methods still do not show great improvement in the area of maldistribution.

Method and apparatus for improved gas/fluid contact


A method for applying a protective resist, such as a negative resist, to a prepatterned wafer in which the resist is applied to the previously generated patterns by a distribution system which includes a holder for the wafer, an xy sliding unit with a programming device, and a dispensing device with a syringe.

The present invention relates to a method for applying a protective resist to a prepatterned wafer.
Semiconductor wafers can be composed of a substrate and membranes produced by etching the substrate from the back. Silicon is preferably used as the substrate material and thus as the material for the membranes. In a number of sensor applications, patterns must be produced from the membranes by dry etching the front of the wafer, i.e., the side containing the membranes. In the case of dry etching, it is necessary to protect the membrane undersides, which were produced by cavern etching the substrate from the back, during the dry etching process.
This back protection performs the following important functions during dry etching, preferably using an anisotropic plasma etching process as the dry etching process.
The back protection prevents etching gases, such as fluorine, from attacking the membrane underside after etching through the front of the membrane, since the caverns are sealed by the protective layer and the membrane undersides are also covered, so that no free silicon that could be attacked by the etching gases, such as fluorine, is exposed on the back.
The back protection also makes it possible to overetch patterns in the plasma that are already etched through, i.e., the etchant attack on the silicon side walls of patterns already etched from the membrane is reduced because the undersides of the membrane are protected.
In addition, a seal is provided for the back of the wafer, to which helium must be applied toward the front as a convection medium during plasma etching to cool the substrate. This cooling thus continues even after the front membrane is partially etched through because the back protection prevents the helium from escaping into the chamber interior of the vacuum system.
Furthermore, the wafer is stabilized and the patterns, which are fragile after etching, are protected mechanically by the back resist. Even in the extreme case of wafer breakage, due to the fragile cavern regions, a fractured wafer can still be extracted from the plasma etching chamber as a single unit without leaving any fragments on the substrate electrode, which would require laborious cleaning of the plasma etching system.
Finally, the back protection can serve as a defined etching barrier. Because the silicon etching process stops when it reaches the resist layer, an end point detection system equipped with optical emission spectroscopy (OES) can be used to determine when the resist layer is reached. Without the resist, silicon etching would continue to the back of the wafer, i.e., there would be no detectable end point.
However, the back protection must also satisfy the following conditions:
The protective resist should always remain inside the caverns and not spread across the remaining back of the wafer so that the wafer does not stick to or contaminate the substrate electrode or components of the load-lock device.
In addition, the protective resist should not blister or flake during the plasma etching process, when it is subjected to thermal load, thus preventing contamination of the substrate electrode or the load-lock devices and ensuring that the back of the wafer, to which the helium is applied, remains sealed against the chamber interior.
There should also be adequate selectivity toward the positive resist, which, during plasma etching, is usually located on the front to define the pattern, so that the back resist in the caverns or used to protect local areas is not damaged when the positive resist on the front is developed by photolithography or removed during or at the end of the process.
Up to now attempts have been made to protect the back by applying a positive resist all over the back of the wafer and to pattern it through photolithography so that it remains only in the caverns and not on the remaining back of the wafer. However, using a positive resist at this point does not produce the desired result. It would not be possible to reliably apply negative resists or, in particular, non-photopatternable polymers in this manner, nor could they be restricted to the cavern interior. However, those resists that are the most resistant to hydrofluoric acid vapor, for example, cannot be photopatterned, since they lack functional groups, which are an important prerequisite for sealing against HF.
The use of a positive resist for filling the caverns is also associated with the following problems: it must be spun onto the wafer very thickly and subsequently photopatterned, i.e., exposed and developed. To do this, a sticky wafer, i.e., one which has not be completely baked or hardened, must be processed with appropriate lithographic equipment. Because they contain solvents and volatile non-crosslinked monomers, however, thick positive resists blister easily during drying and at high temperatures, and they tend to flake off the undersides of the caverns in large areas. In addition, the back of the wafer, which initially is sticky all over, makes it very difficult to process the wafer. This is due to the thick resist, which initially is located all over the wafer according to this method.
Because an identical resist type does not allow for adequate selectivity between the front resist and the back resist, difficulties arise when developing the front resist because, for example, the developer used to partially strip the front resist during developing also has a very corrosive effect on the back resist. The same is true when removing the front resist from the entire surface later on, if possible without damaging the back protection. Indeed, the back protection is also damaged to the extent that the wafer, for example, cannot be further processed if any additional steps are needed.
The positive resist also cannot provide a helium seal or adequate back protection after membrane etching because it blisters and becomes permeable in the plasma due to the thermal and chemical load imposed by the plasma etching process.
An object of the present invention is therefore to provide a method which overcomes the described disadvantages of the related art.
According to the present invention, a method is provided for applying a protective resist to a prepatterned wafer, characterized in that the resist is applied by a distribution system, which includes a holder for the wafer, an xy sliding unit with a programming device, and a dispensing device. The dispensing device dispenses the optimum protective resist and the optimum amount of protective resist selectively into the caverns.
In one example embodiment of the present invention, the protective resist is applied to the back of the wafer in micromechanically prepatterned caverns.
The use of a negative resist or a resist made of non-photopatternable polymers as the protective resist is also preferred. In this case, benzo cyclobutadiene, polymethyl methacrylate, polyimide, or epoxide can preferably be used. Due to their high chemical and thermal stability, negative resists are especially advantageous and yet they can be removed later on cleanly and without leaving a residue, for example in an oxygen plasma ambience.
The distribution system includes the following three components:
1. It has a holder for the wafer, allowing the latter to be positioned in the distribution system in a precisely defined, reproducible manner with respect to wafer orientation. This is achieved, for example, by a plate having a recess milled into the plate and corresponding to the wafer geometry, with this plate also encompassing the wafer flat. This clearly defines the position and alignment of the wafer.
2. The distribution system also includes an xy sliding unit with a programming device, which holds the actual sprayer and can selectively move to each individual cavern position, thus scanning the entire back of the wafer, controlled by a program. Each cavern in the wafer corresponds to one explicitly entered program position.
3. Finally, the distribution system also has a dispensing device, which is electrically connected to a programming device and is controlled by the latter, i.e., a device that can inject a precisely defined amount of resist from a syringe through a needle-shaped nozzle upon receiving a command from the program. The amount of resist injected can be predetermined by the applied injection pressure, the nozzle cross-section, and the preprogrammed injection time. The resist is preferably prevented from dripping at the end of injection by applying a vacuum which withdraws the resist from the nozzle immediately after injection. This reliably prevents resist droplets from falling onto the back of the wafer outside the caverns.
This distribution system, which was adapted specifically to the method according to the present invention, moves to a cavern position, injects a pre-selected amount of resist into the relevant cavern, and sends confirmation of the end of injection to the programming device, after which the distribution system moves on to the next cavern and repeats the process until all caverns in the wafer have been filled. At the beginning of the program, resist is first injected into a collecting vessel multiple times, such as five time, from an idle position in order to place the nozzle in a defined initial state and, in particular, to remove dried or thickened resist residue from the nozzle. The needle then passes by a resist wiper to wipe off any resist droplets still clinging to the needle before they reach the surface of the wafer and to also divert them to the collecting vessel. In its simplest form, this wiper can be the edge of the resist collecting vessel itself, which in this case must be high enough to allow the end of the needle to pass over it without contact, at the same time wiping off the resist droplets clinging to the needle as it passes by. At the end of the program, the distribution system returns to an end position, which can, but does not have to be, identical to the idle position to which the device moved in the beginning.
Using the distribution system, which moves to each cavern position on the back of a wafer, controlled by a program, using an xy sliding table, where an injector deposits a precisely defined amount of resist, all back caverns are uniformly filled with a freely selectable amount of protective resist without the resist contaminating any other point on the back of the wafer. It is also possible to provide each cavern with an individual amount of resist, especially if the caverns are of different sizes.
In a further preferred embodiment, the front of the wafer is coated with a positive resist.
In the method according to the present invention, the caverns in the back of the wafer can be selectively coated with a resist with the help of the distribution system, preferably using a negative resist or a resist which is resistant to the developers or solutions for partially or completely removing the positive resist on the front. This makes it possible to carry out front-side lithography and front-side aftertreatment or removal of the resist without impairing the protection on the back of the wafer, thus keeping it intact for subsequent processes.
The negative resist has an advantage over the positive resist in that it has a high chemical and thermal stability so that it does not blister or flake during baking or during subsequent plasma etching, fully maintaining its protective effect and, for example, avoiding the risk of contaminating the substrate electrode of the plasma etching device. In addition, the plasma etching process can be carried out reliably because wafer sealing and protection are guaranteed and an end point signal is defined by OES (optical emission spectroscopy).
In a further example embodiment, the protective resist is applied with the dispensing device with one or more injection operations per cavern. The injection operations can also take place from different positions above the caverns. The advantage of this is that the caverns can be filled very uniformly. For this purpose, resist can be injected multiple times into each cavern during the same pass, or multiple passes across the wafer can be performed.
It may also be necessary, especially in the case of complex cavern topographies, to provide different regions of the caverns with resist selectively. It is also possible to run the entire injection program multiple times across the same wafer, possibly with the use of offsets to reach different cavern positions. In addition, different resists can be used per program run or cycle. For example, it is possible to inject a thin resist, yet one which adheres firmly to the silicon, in a first program cycle and then, in a second program cycle, a thicker resist is used which by itself would not adhere well directly to the silicon, but which can nevertheless be applied in a thick layer. However, the first application of the thin resist allows the entire system of resist layers to adhere well to silicon because the second resist adheres well to the first, and the first adheres well to silicon.
The negative resists and positive resists according to the method are commercially available resists commonly used in semiconductor and micromechanical applications and sold by companies such as OCG, KTI Chemicals, and Hoechst.
The method according to the present invention now makes it possible in a highly advantageous manner to use a negative resist or other polymeric resists for coating the back of a wafer, with these resists being resistant or largely resistant to the developer or stripping solutions used for the positive resist on the front of the wafer. The positive resist can thus be photopatterned, developed or even completed removed at the end of the process without damaging the back protection. In particular, it is now also possible to use non-photopattemable protective resists which are especially resistant, for example, to hydrofluoric acid or other chemical reagents. The negative resists and the resists that are resistant to the developer or stripping solutions have the advantage that they do not blister during baking, adhere very well in the hard-baked state, are highly selective toward the positive resist, and do not foam during plasma etching or contaminate the substrate electrode of the plasma etching device. In addition, these resists have a high mechanical strength so that they can stabilize the wafer after etching and can also reliably withstand the helium pressure applied to the back and used to cool the wafer during plasma etching. One particular advantage is good stability in relation to the fluorine radicals in the plasma etching gas which occur during plasma etching.
In a further embodiment, the protective resist can also be applied to predetermined regions on specific, prepatterned fronts of the wafer to protect the latter, for example, against a corrosive medium. These regions can be, for example, regions of buried conductor paths and/or contact surfaces which need to be protected against a corrosive medium, e.g. hydrofluoric acid, in subsequent processes.
It is possible, for example, to selectively protect front regions with a negative resist or other, e.g. non-photopatternable, resists in this manner. This can be done, for example, prior to etching the sacrificial layer in hydrofluoric acid vapor if the reactive oxide is to remain in individual areas and therefore be protected. This may be necessary, for example, in the region of conductor paths that are buried by silicon dioxide or the region of contact surfaces for electrical insulation reasons, thus avoiding leakage currents. In the case of prepatterned wafer fronts, it is practically impossible to achieve selective coverage of the precise areas to be protected using methods such as spin-coating and photolithography.
The sliding unit preferably scans the front or back of the wafer, controlled by a program. However, electronic image processing can also be used to identify and move to the positions for applying the resist. This means that, instead of precisely positioning the wafer in a specific holder, it is also possible to simply place the wafer relatively imprecisely in the process station and identify and move to the cavern positions by electronic image processing. Image processing can also be used to simultaneously perform a quality check to determine the success of injection, i.e., a check is carried out to determine whether certain resist coating images were obtained.
Although image processing requires a highly complex electronic system, it renders superfluous the explicit programming of each individual cavern position in another advantageous embodiment of the present invention because the system simply injects resist into each cavern detected and xe2x80x9celectronicallyxe2x80x9d identified by the program. It is no longer necessary to individually adjust the program positions to the inserted wafer, but instead the program selects its own cavern positions via image processing, which greatly increases flexibility under manufacturing conditions and helps avoid errors. It is even possible for the program to detect the cavern size automatically and to dispense the optimum amount of resist specifically for each cavern, according to its size.
Instead of placing the wafer in the holder manually, it is also possible to combine this with an automatic loading system. This system can, for example, place one wafer after the other precisely into the process position from a cartridge station and then remove them again at the end of the process. It is also possible to use a less precise automatic handling system and equip it with an electronic image processing system for identifying and moving to the individual caverns, as described above.

Method for applying a protecting lacquer on a wafer


A stent comprises a plurality of serpentine circumferential bands, and a plurality of connector columns. Each connector column is located between two adjacent circumferential bands and comprises one or more connector struts. Each connector strut is connected at one end to one serpentine circumferential band and at another end to another serpentine circumferential band. The number of connectors per connector column decreases from the first free end of the stent to the second free end of the stent.

The use of stents in bodily lumen is well known. A stent is typically delivered in an unexpanded state to a desired location in a bodily lumen via a stent delivery device such as a catheter. Once the stent is at the desired bodily location, it is either expanded with a balloon or other suitable device or allowed to expand by, for example, withdrawing a restraining sheath.
Because a stent and stent delivery system often must be delivered through tortuous anatomy, it would be desirable for the stent delivery system to have a smooth transition of stiffness from the proximal end of the system to the distal end of the system. Less flexibility is desirable at the proximal end of the stent delivery system to allow for adequate pushability of the system. More flexibility is desirable at the distal end to ensure adequate trackability of the system.
There remains a need for stents as well as stent delivery systems including stents that provide for sufficient pushability and adequate trackability in vivo.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well for the purposes of complying with 37 C.F.R. 1.72.


In a touchscreen viewing device, a method for implementing a crease effect. The method includes receiving a swipe input related to an image displayed on a touch screen of a viewing device, upon determination that the swipe input will generate an item end effect, causing a crease effect to appear on the image in response to the swipe input, and subsequent to the end of the swipe input, undoing the crease effect on the image to return the image to an original effect.

A touchscreen is an electronic visual display that the user can control through simple or multi-touch gestures by touching the screen with one or more fingers. Some touchscreens can also detect objects such as a stylus or ordinary or specially coated gloves. The user can use the touchscreen to react to what is displayed and to control how it is displayed (for example by zooming the text size).
The touchscreen enables the user to interact directly with what is displayed, rather than using a mouse, touchpad, or any other intermediate device (other than a stylus, which is optional for most modern touchscreens). Touchscreens are common in devices such as game consoles, all-in-one computers, tablet computers, and smartphones. They can also be attached to computers or, as terminals, to networks. They also play a prominent role in the design of digital appliances such as personal digital assistants (PDAs), satellite navigation devices, mobile phones, and video games.
The popularity of smartphones, tablets, and many types of information appliances is driving the demand and acceptance of common touchscreens for portable and functional electronics. Touchscreens are popular in the medical field and in heavy industry, as well as in kiosks such as museum displays or room automation, where keyboard and mouse systems do not allow a suitably intuitive, rapid, or accurate interaction by the user with the display's content. Computer systems are increasingly being used to handle video streams and video information in addition to high performance 3D rendering.

Method and system for a creased paper effect on page limits


A floor cleaning wipe comprising a water insoluble substrate which is impregnated with a floor cleaning composition.

The present invention relates to a floor cleaning wipe which comprises a water insoluble substrate which has been impregnated with a liquid floor cleaning composition.
The patent literature describes numerous wipes for both body cleaning and cleaning of hard surfaces but none describe the instant cleaning wipes which have improved cleaning characteristics in the minimization of streaking and residue, together with optimum mileage.
U.S. Pat. Nos. 5,756,612; 5,763,332; 5,908,707; 5,914,177; 5,980,922 and 6,168,852 teach cleaning compositions which are inverse emulsions.
U.S. Pat. Nos. 6,183,315 and 6,183,763 teach cleaning compositions containing a proton donating agent and having an acidic pH.
U.S. Pat. Nos. 5,863,663; 5,952,043; 6,063,746 and 6,121,165 teaches cleaning compositions which are water emulsions.
A floor cleaning wipe for cleaning floors comprises a water insoluble substrate consisting of two layers which is impregnated with a liquid cleaning composition containing tall oil soap, a sultaine surfactant, an amine oxide, a perfume, a preservative and water, wherein the liquid cleaning composition is not an emulsion and does not contain a sulfate or sulfonate surfactant, proteins, metallic salts, enzymes, amides, sodium hypochlorite, dimethicone, N-methyl-2-pyrrolidone, monoalkyl phosphate or silicon based sulfosuccinate.
The present invention relates to a floor cleaning wipe for hard surfaces which comprises approximately:
(a) 5 wt. % to 20 wt. % of a water insoluble substrate formed from two layers; and
(b) 80 wt. % to 95 wt. % of a liquid floor cleaning composition being impregnated in said water insoluble substrate, wherein said liquid cleaning composition comprises:
(i) 0.05 wt. % to 0.5 wt. %, more preferably 0.075 wt. % to 0.25 wt. % of at least one alkali metal salt of a long chain unsaturated fatty acid having about 8 to about 24 carbon atoms such as a refined tall oil fatty acid;
(ii) 0.001% to 0.01% of a sultaine surfactant;
(iii) 0.001% to 0.01% of an amine oxide surfactant;
(iv) 0 wt. % to 0.7 wt. %, more preferably 0.01 wt. % to 0.05 wt. % of a preservative;
(v) 0.01 to 0.5 wt. % of a perfume;
(vi) 0 to 0.4 wt. %, more preferably 0.01 to 0.2 wt. % of a metal chelant; and
(vii) the balance being water, wherein the composition has a pH of about 9 to about 11, more preferably about 9.4 to about 10.6.
As used herein and in the appended claims the term xe2x80x9cperfumexe2x80x9d is used in its ordinary sense to refer to and include any non-water soluble fragrant substance or mixture of substances including natural (i.e., obtained by extraction of flower, herb, blossom or plant), artificial (i.e., mixture of natural oils or oil constituents) and synthetically produced substance) odoriferous substances. Typically, perfumes are complex mixtures of blends of various organic compounds such as alcohols, aldehydes, ethers, aromatic compounds and varying amounts of essential oils (e.g., terpenes) such as from 0% to 80%, usually from 10% to 70% by weight, the essential oils themselves being volatile odoriferous compounds and also serving to dissolve the other components of the perfume.
In the present invention the precise composition of the perfume is of no particular consequence to cleaning performance so long as it meets the criteria of having a pleasing odor. Naturally, of course, especially for cleaning compositions intended for use in the home, the perfume, as well as all other ingredients, should be cosmetically acceptable, i.e., non-toxic, hypoallergenic, etc. The instant compositions show a marked improvement in ecotoxocity as compared to existing commercial products.
The preferred long chain unsaturated fatty acids of the instant invention have about 8 to about 24 carbon atoms, more preferably about 10 to about 20 carbon atoms. A preferred unsaturated fatty acid mixture is a refined tall oil fatty acid. A typical tall oil fatty acid contains mono unsaturated C16-18 fatty acid; a C18 diene unsaturated fatty acid; a C16-18 triene unsaturated fatty acid; and a C16-18 saturated fatty acid. Other unsaturated fatty acids that are usable in the instant compositions are unsaturated vegetable oil fatty acids, including soy, peanut, corn, cottonseed, linseed and refined oleic fatty acids, and fatty acids consisting predominantly of C18 (average) unsaturated fatty acids and mixtures thereof. The unsaturated fatty acid reacts in situ with the alkali metal hydroxide to form the alkali metal salt of the unsaturated fatty acid.
The composition contains about 0.001 wt. % to about 0.01 wt. % of an amine oxide, more preferably about 0.003 wt. % to about 0.08 wt. %. The preferred amine oxide is cocoamido-propyldimethyl amine oxide. The amine oxide is depicted by the formula:
wherein
R1 is an alkyl, 2-hydroxyalkyl, 3-hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain from about 8 to about 18 carbon atoms; R2 and R3 are each methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3-hydroxypropyl; and n is from 0 to about 10. Particularly preferred are amine oxides of the formula:
wherein
R1 is a C12-18 alkyl and R2 and R3 are methyl or ethyl. The above ethylene oxide condensates, amides, and amine oxides are more fully described in U.S. Pat. No. 4,316,824 (Pancheri), incorporated herein by reference. An especially preferred amine oxide is depicted by the formula:
wherein
R1 is a saturated or unsaturated alkyl group having about 6 to about 24 carbon atoms, R2 is a methyl group, and R3 is a methyl or ethyl group. The preferred amine oxide is cocoamidopropyl-dimethylamine oxide.
The composition also contains about 0.001 wt. and to about 0.01 wt. %, more preferably about 0.003 wt. % to about 0.08 wt. % of a sultaine which is preferably a cocoamido-propylhydroxy sultaine. The sultaine can be depicted by the formula:
wherein
R1 is a saturated or unsaturated alkyl group having about 6 to about 24 carbon atoms, R2 is a methyl or ethyl group, R3 is a methyl or ethyl group, M+ is about 1 to about 6, and n+ is an alkali metal cation. The most preferred hydroxysultaine is a potassium salt of cocoamidopropyl hydroxysultaine.
The combination of the amine oxide and the sultaine functions to serve as a viscosity control agent while functioning as a means for the dispersion of lime soap.
The final essential ingredient in the instant composition is water. The proportion of water in the compositions generally is in the range of 98 wt. % to 99.8 wt. %.
The floor cleaning composition of this invention may, if desired, also contain other components either to provide additional effect or to make the product more attractive to the consumer. The following are mentioned by way of example: Colors or dyes in amounts up to 0.5%. The preservative is selected from the group consisting of formaldehyde, iodo propynyl butyl carbamate, 5-bromo-5-nitro-dioxan1,3; 5chloro-2-methylisothalizolin-3-one. Typical methyl chelating agents are ethylene diamine tetraacetate acid-sodium salt, hydroxy ethylene theylene diamine triacetic acid-trisodium salt and ethylene diamine disuccinate pH adjusting agents, such as sulfuric acid or sodium hydroxide, can be used as needed.
The cleaning compositions are prepared by simple batch mixing at 25xc2x0 C.-30xc2x0 C. The water insoluble substrate is impregnated with the liquid cleaning composition by means of a positive impregnation process. The liquid is positively fed into the water insoluble substrate through a controlled gear pump and injection bar at a ratio of about 6 to 9 grams of liquid cleaning composition to about 1 gram of the nonwoven fabric.
The water insoluble substrate can be square, rectangular, oval, circular or any other geometrically shape such that the water insoluble substrate can be readily attached to the head of a mop having a similar geometrical shape. The water insoluble substrate comprises two layers which are bonded together at least along the peripheral outer edges of the two layers, wherein the bonding can be any suitable means such as mechanical, ultrasonic or chemical means. One of the layers is a hydrophobic chemically bonded polyester nonwoven fabric and comprises 5 wt. % to 25 wt. % of the water insoluble substrate and the other layer is needle punched cellulose nonwoven fabric which comprises 75 wt. % to 95 wt. % of the water insoluble substrate.
Preferred water insoluble substrate is manufactured by the American Nonwoven Corporation and designated as 2380.
The following example illustrates a liquid cleaning composition of the described invention. The exemplified composition is illustrative only and does not limit the scope of the invention. Unless otherwise specified, the proportions in the examples and elsewhere in the specification are by weight.


The invention relates to a vessel filter comprising at least one conductor loop (21) which forms the inductance of an electric resonance circuit. According to the invention, the conductor loop (21) forms the vessel filter or parts of a vessel filter. The invention provides a vessel filter which is characterized by good mechanical properties, especially a high degree of flexibility and stability, offering good representability in MR imaging systems.

The invention concerns a vessel filter that includes a conductor loop that forms the inductance of an electrical resonance circuit.
Vessel filters are structures that are inserted into traversed veins and arteries of the human or animal body, especially the inferior vena cava, in order to prevent penetration of blood clots or sclerotic vascular material into organs of the body, especially the lungs and brain.
For application, vessel filters are generally mounted or fastened in the unexpanded state on a wire to be introduced to the body or brought to the target location of implantation in a catheter via a surgical vein access and then deployed. The diameter of the vessel filter is then enlarged, so that the filter presses against the vessel wall and is fastened there.
There is a requirement, for displaying of vessel filters by imaging methods during implantation and for later functional control or removal. Recently, magnetic resonance (MR) imaging systems have increasingly gained importance in medical diagnosis. Interventional and minimally invasive techniques, like puncture, catheterization and surgical procedures, in particular, are conducted under MR tomographic control. Depiction and position determination of a vessel filter in an MR imaging system, however, is difficult. Metal vessel filters are only visible as an artifact, and vessel filters made of plastic are scarcely visible at all because of their fine structure in the MR image.
It is known from WO-A1 99/19739 for a clear and signal-intensive representation of a medical device in an MR image to integrate in this device an oscillating circuit that generates an altered signal response in a locally limited region or around the medical device, which is depicted with location resolution. The resonance frequency of the oscillating circuit is essentially equal to the resonance frequency of the emitted high-frequency radiation of the MR imaging system. The to oscillating circuit in the medical device can then be made of the same material. In one variant, the oscillating circuit is integrated in the medical device, so that the inductance appears together with it during deployment of the device.
MR-active vessel filters are also known from the literature. These instruments consist of a filter part and a separate conductor loop wound around the filter. After introduction into the body, the conductor loop and vessel filter can be deployed.
A shortcoming in vessel filters of this type is the fact that they consist of a basic framework for the filter function onto which a conductor loop must be wound in order to provide the device with the desired MR activity. The connection of two components has an adverse effect on the mechanical stability of the vessel filter.
The task of the present invention is to provide a vessel filter characterized by good mechanical properties, especially a high degree of flexibility with simultaneous stability, and one that is readily viewable in an MR imaging system.
This task is accomplished according to the invention by a vessel filter with the features of a conductor loop, forming the inductance of an electrical resonance circuit. Preferred and advantageous embodiments of the invention are mentioned in the dependent claims. The conductor loop forms the vessel filter or at least parts of the vessel filter. The concept according to the invention therefore lies in using only one structure, namely, a conductor loop, both to form the actual filter and for the inductance. In combination with a capacitance, a resonance circuit is therefore provided.
In a preferred embodiment, the vessel filter forms several resonance circuits, each with at least one conductor loop. Because of this, a situation can be achieved in which the vessel filter can be operated and detected at several different MR frequencies. It can also be prescribed that several resonance circuits be coupled to each other.
In an advantageous variant, the vessel filter forms at least one integrated circuit coupled to the resonance circuits so that they can be adjusted or tuned by the integrated circuit in addition to the resonance circuit or the resonance circuits. The integrated circuit permits external influencing of the resonance frequency with to adjustment or tuning, for example, by switching on and/or switching off the inductive or capacitive elements of the oscillating circuit. The power supply of the integrated oscillating circuit can occur through a small power supply (for example, battery), or also by inductive coupling of energy from an electromagnetic field.
In an advantageous variant, the vessel filter has spacers and/or insulators that keep the individual sections of the conductor loops at a spacing from each other and/or insulate them relative to each other. Because of this, short circuits between individual conductor windings are prevented. In addition, the insulators, in a particularly advantageous variant, are simultaneously a part of the internal capacitance in conjunction with at least one conductor loop. This develops by a connection and simultaneous insulation of the ends with an insulator (for example, polymer, ceramic, composite) that represents a dielectric and forms at least one capacitance (capacitor) connected electrically in the network with at least two conductors separated by the insulator.
The conductor loop is advantageously enclosed by a nonconductor, especially plastic and/or ceramic. This serves for increased the lifetime of the vessel filter by increased mechanical stability and its disturbance-free function. In a particularly preferred variant, insulation serves to reduce and regulate the parasitic capacitance, wherein the insulation can also be used to tune the oscillating circuit, i.e., for fine adjustment of the resonance frequency. Fine adjustment is also possible by deformation of the filter and therefore a change in inductance. This can be determined primarily by expansion or compression or by limiting vessel diameter. The vessel filter according to the invention therefore gets by in its simplest variant without an additional capacitance, since a combination of an internal and parasitic capacitance is sufficient for its function. Insulation also ensures that no electrical contact to other conductor loops is present between the ends of the individual conductor loops which would alter the prescribed inductance by a short circuit.
In an advantageous variant of the vessel filter according to the invention, the resonance circuit has a resonance frequency, especially in the high-frequency range, which corresponds to the frequency of an external magnetic field, especially an MR tomograph (MRT). Implantation and function of the vessel filter can therefore be observed by imaging MR methods. However, it is also conceivable to provide an to oscillating circuit with a resonance frequency in a different frequency range.
In an advantageous variant, the conductor loop has at least one electrically nonconducting material on whose surface at least one conducting material is applied, especially gold, platinum, tantalum and/or conducting alloys. The choice of specially conducting materials, for example, gold, improves the formation of resonance. Several layers of an insulator and conductor can also be applied to the conductor loop.
The conductor loop of the vessel filter is advantageously designed so that it can be deployed. The resonance circuit can preferably be formed during and/or after implantation in a biological medium. The vessel filter can therefore be implanted in folded form and deployed during implantation or only at its target location. This permits implantation starting from small veins or arteries in the periphery of the body. However, in principle, it is also possible to form it before transplantation.
In an advantageous variant, the vessel filter according to the invention has several conductor loops. This permits greater flexibility in configuring the vessel filter and a higher filter function. In addition, the resonance can be further improved by the presence of several conductor loops.
"Conductor loop" is understood to mean a conductor consisting of one piece. "Conductor loop winding" is understood to mean a section of the conductor loop that is brought into a specific shape, in which the straight shape is also included.
In another advantageous variant, the so-called umbrella filter, the vessel filter has several conductor loop windings guided so that the conductor loop forms an elongated base that is closed on at least one side with a screen-like filter cage. This variant leads to a particularly good filter effect.
The term "filter cage" is used to denote the part of the vessel filter that contains the conductor loop windings, which, owing to the fact that they are brought together on at least one long side of the filter, are in a position to retain thrombi of clotted blood or sclerotic material in the blood vessel.
In another advantageous variant, the so-called diamond filter, the vessel filter has several conductor loop windings guided so that the largest spacing of the loop windings from each other is present in the center and tapers to at least one long side. In a particularly advantageous variant, the conductor loop windings taper to two sides, which improves the filter effect. Independently of the number of filter cages, the advantage of this variant lies in the fact that a large part of the conductor loop windings lies against the vessel wall, which leads to good and permanent and tilting-free fastening to the vessel wall, which can additionally be supported by anchoring in the vessel wall with hooks. In addition, this type of filter permits good illumination of the filter interior in the MR method.
In another advantageous variant, also referred to as a tulip filter, the vessel filter has at least one conductor loop winding that runs together in a filter cage on one side of the filter and extends leg-like on the other side of the filter. A filter forming at least one extension that serves for connection of the filter to a vessel wall is particularly preferred. With particular advantage, the regions of the conductor loop winding adjacent to the extension are at a limited spacing from each other. It is particularly preferred that the adjacent regions of the conductor loop winding in the extension be connected to each other without an intermediate space, especially by welding, soldering or pressing. However, they can also consist of one piece, i.e., the continuation is formed by a one-piece part connected to the conductor loop winding. Because of this, the contact surface of the vessel filter with the vessel wall is minimized and a situation is achieved in which the filter can be removed without rupturing the vessel wall, since the intima grows pocket-like around the extension.
It is particularly advantageous if the extension points in the direction of blood flow of the vessel in which the filter is arranged. Because of this, anchoring in the vessel wall and intima of the vessel is achieved, which optimally counteracts the flow force of the blood. To remove the vessel filter, the filter is initially moved against the direction of blood flow, in order to remove the extension from the intima pockets. After collapse of the filter, it can be removed without problem from the body.
It is also advantageous if the extension points in the direction of the vessel wall. This also requires a fixed anchoring in the vessel wall, both by growing of the intima around the extension and by concentration of the pressure force on this extension. Anchoring can be improved by additional hooks. An improved anchoring can be improved by a sealing coating with greater depth of roughness.
It is particularly preferred that the extensions be arranged moveably against the braces, for example, of the tulip filter. The resonance frequency of the filter also depends on its diameter. During deployment of this variant of the vessel filter, the extensions shift relative to the braces as a function of the vessel diameter, which determines the width of deployment. Because of the moveability, any change in resonance frequency is compensated by a change in filter diameter so that the resonance frequency remains almost constant as a result. Imaging in MR therefore remains optimally independent of vein diameter. Anchoring in this case is assumed by the fixed brace and is possible by anchoring with hooks.
In another advantageous variant, the so-called low-pass birdcage filter, the vessel filter contains at least two foldable conductor loops, especially guided in zigzag fashion, in which one conductor loop forms a capacitance at least one reversal point with at least another conductor loop or permits connection of an external capacitance, and the reversal points of at least one of the conductor loops on one side have a smaller spacing relative to each other than on the other side, and, in particular, form a filter cage.
In another advantageous variant, the so-called high-pass birdcage filter, the vessel filter contains at least two conductor loops guided in closed vessel filters in the longitudinal direction and connected on at least one end to another conductor loop by a capacitance.
Anchoring of the birdcage filter in the vessel wall can be produced by hooks. One means of connection for coupling between filters and catheters can also be a filter component.
In both cases, a very homogeneous magnetic field is created by the arrangement of inductances and capacitances according to the principle of a birdcage coil, which permits excellent. MR illumination and therefore intravascular imaging even of the immediate vicinity of the filter.
The design of a double-filter is particularly advantageous. This is understood to mean a vessel filter that forms a filter cage on both opposite long sides. Double-filters can be implemented, for example, in the variants of the umbrella, diamond and birdcage filter. The advantage of a double-filter lies in better illumination in the MR image with simultaneously optimized filter effect.
The individual windings of the conductor loops are advantageously arranged in the longitudinal direction of the vessel filter. This leads to a particularly mechanically to stable filter and also leads to good and permanent connection with the vessel wall. This is necessary, in particular, for a vessel filter permanently remaining in the vessel.
In an advantageous variant, the vessel filter according to the invention has at least one brace connected to the conductor loop. These braces improve the mechanical stability of the filter and increase the filter effect. At the same time, they can also serve to anchor it in the vessel wall. The braces can be fastened on their ends with plastic sealant or a crimping sleeve mounted in insulated fashion.
In another advantageous variant, the braces are conducting and are connected conducting to the conductor loop. Because of this, during use of conductor loop material, production is possible from only one piece. They therefore become part of the coil and can improve the resonance.
In a particularly preferred variant, the individual braces are connected moveably to the individual conductor loop windings.
A vessel filter containing braces made of bioresorbable material is particularly advantageous. After the braces are broken down by the body, the vessel filter has fewer connections to the veins or arteries than right before implantation. The vessel filter therefore sits loosely against the tissue. This permits easy removal of the implant from the body.
In an advantageous variant, the vessel filter forms at least one semiconductor element, especially a diode and/or a transistor and/or an integrated circuit. This diode permits tuning of the resonance frequency which leads to better detectability in an MR system. The transistor can also tune the oscillating circuit and be controlled via an additional inductive switching coil.
The conductor loop is advantageously formed from a material piece, especially a tube, a wire or electrically-conducting plastic. This permits simple and cost-effective production.
It is advantageous to produce the conductor loop by repeated lengthwise cutting of a tube, especially a Nitinol tube, and then expansion. It is particularly advantageous to guide the conductor loop on the sides in meander-like fashion. With this type of production, insulation of the conductor parts from each other is particularly facilitated.
The ends of the conductor loop windings are preferably joined by welding, gluing, clamping, sealing and/or shape-mating, especially by thermally initiated shrinkage of a cylinder from a shape-memory material.
In another advantageous variant, the vessel filter contains at least one conductor loop winding, provided with at least one hook. These hooks permit additional fastening of the filter in the vessel wall and therefore prevent filter wandering.
The vessel filter advantageously has at least one connection device, for example, a lug, for coupling with a device for introduction and/or extraction of the filter, for example, a catheter. This permits the operator's easy handling of the vessel filter during implantation and/or extraction.
The vessel filter also preferably contains at least one means for braking of the filter during introduction to the body. The braking device is preferably formed by a region of increased diameter or by a local constriction of the catheter. This permits the operator greater manual control and therefore more precise implantation in the blood vessel.
It is particularly advantageous, if the connection device is the braking device.