A polarization independent-type semiconductor optical amplifier comprises: a strained bulk active layer having a 20 nm to 90 nm-thick and having a tensile strain of a xe2x88x920.10% to xe2x88x920.60% strain amount; clad layers provided, sandwiching the strained bulk active layer; and a resonance suppressing means for suppressing resonance of light due to reflection on a light incident end face and a light exit end face of the strained bulk active layer, incident signal light entering at the light incident end face being amplified and exiting at the light exit end face, and an individual transmission gain of the exit signal light being substantially constant independent of a polarization state of the incident signal light. Whereby drastically increased fiber out saturation powers can be obtained with polarization independence retained.

The present invention relates to a polarization independent-type semiconductor optical amplifier, more specifically to a polarization independent-type optical amplifier for use in wavelength division multiplexing (WDM) communication systems, which has large fiber out saturation powers in a small size and at low consumed electric power.
Recently, corresponding to the drastic increase of communication demand, wavelength division multiplexing systems for multiplexing signal light of a plurality of different wavelengths and transmitting the signal light concurrently in one optical fiber are progressively developed. Such wavelength division multiplexing system includes a number of optical parts for combining, switching and dividing optical signals, and the optical signals are attenuated due to losses in the respective optical parts.
Optical amplifiers are used for compensating such attenuation. A very larger number of optical amplifiers are required in comparison with a number of optical amplifiers used in the conventional optical fiber systems. It is required that the optical amplifiers are small sized and operable at low power consumption.
In addition, it is required that such optical amplifiers used in in-line have less polarization dependence of gains because polarization states of input signal lights are random, and have large fiber out saturation powers so as to have wide input dynamic ranges because fluctuations of power levels of input signal light are large.
Among such various optical amplifiers, semiconductor optical amplifiers (SOAs) are small sized and have small power consumption, and can be designed to be polarization-independent. The semiconductor optical amplifiers are expected to be a loss compensating optical amplifier suitably used in the wavelength division multiplexing systems.
Such polarization independent-type semiconductor optical amplifiers for a 1.55 xcexcm-band in the wavelength band used in the fiber optical communication have been conventionally developed. Such polarization independent-type semiconductor optical amplifier will be explained below.
An internal gain is a gain of the optical amplifier itself. A fiber to fiber gain is a gain of a system as a whole including an optical amplifier provided between an optical fiber on the input side and an optical fiber on the output side with an optical system for optical coupling, such as a lens, etc., disposed therebetween, which takes into account a loss of the system between the exit end face of the input side optical fiber and the incidence end face of the output side optical fiber.
A chip out saturation power is a chip out power given when an internal gain is decreased by 3 dB. A fiber out saturation power is a fiber output power given when a fiber to fiber gain is decreased by 3 dB.
As a semiconductor optical amplifier using a strain-free bulk active layer, P. Doussiere et al., Alcatel have realized a device which includes a bulk active layer of a 430 nm-thick and a 500 nm-width, and which has, at 800 xcexcm-device length and at 200 mA injection current, a below 0.5 dB inter-polarization gain difference, a 29 dB fiber to fiber gain and a +9.0 dBm fiber out saturation power (see, e.g., P. Doussiere et al., IEEE Photon. Technol. Lett., vol. 6, pp. 170-172, 1994 and P. Doussiere et al, OAA ""95, pp. 119-122).
As a semiconductor optical amplifier using a strained Multiple Quantum Well (MQW) active layer formed of a strain-free well layer and an tensile strained barrier layer, Magari et al., NTT realized a device including a strained MQW layer which is formed of 10 well layers each having a 5 nm-thick and a 0% strain amount and 11 barrier layers each having a 5 nm-thick and a xe2x88x921.7% strain amount, and is sandwiched between 50 nm-thick and 100 nm-thick separate confinement heterostructure (SCH) layers, and which has, at a 660 xcexcm-device length and 200 mA injection current, a below 1.0 dB inter-polarization gain difference, a 27 dB internal gain (a 13 dB fiber to fiber gain), a +14.0 dBm chip out saturation power (a +7.0 dBm fiber out saturation power) (see, e.g., K. Magari et al., IEEE Photon. Technol. Lett., vol. 2, pp. 556-558, 1990, K. Magari et al., IEEE Photon. Technol. Lett., vol. 3, pp. 998-1000, 1991, and K. Magari et al., IEEE J. Quantum Electron., vol. 30, pp. 695-702, 1994).
As a semiconductor optical amplifier similarly using a strained MQW active layer formed of a strain-free well layer and a tensile strained barrier layer, A. E. Kelly, et al., BT realized a device including a strained MQW layer which is formed of 10 well layers of a 0% strain amount and 11 barrier layers of a xe2x88x920.67% strain amount and is sandwiched between 25 nm-thick SCH layers, and which has, at a 2000 xcexcm-device length and 200 mA injection current, a below 0.5 dB inter-polarization gain difference, a 27 dB fiber to fiber gain and a +7.5 dBm fiber out saturation power (see, e.g., A. E. Kelly et al., Electron Lett., vol. 32, pp. 1835-1836, 1996 and A. E. Kelly et al., Electron Lett., vol. 33, pp. 536-538, 1997).
As a semiconductor optical amplifier using a strained MQW active layer formed of a compressive strained quantum well layer, a tensile strained quantum well layer and a strain-free barrier layer, M. A. Newkirk et al., ATT realized a device including a strained MQW layer which is formed of 3 compressive strained quantum well layers each having a 3.5 nm-thick and a +1.0% strain amount, 3 tensile strained quantum well layers each having a 16.0 nm-thick and a xe2x88x921.0% strain amount, and 7 barrier layers each having a 10 nm-thick and a 0% strain amount, and which has, at a 625 xcexcm-device length and 150 mA injection current, a below 1.0 dB inter-polarization gain difference, a 13 dB internal gain (a 4.4 dB fiber to fiber gain) and a +11.1 dBm chip out saturation power (a +6.8 dBm fiber out saturation power) (see, e.g., M. A. Newkirk et al., IEEE Photon. Technol. Lett., vol. 4, pp, 406-408, 1993).
As a semiconductor optical amplifier using a strained MQW active layer formed of a compressive strained quantum well layer and a tensile strained barrier layer, D. Sigogne et al., CNET realized a device which includes a strained MQW layer formed of 16 compressive strained quantum well layers each having a 8 nm-thick and a +1.1% strain amount and 16 tensile strained barrier layers of a 7 nm-thick and a xe2x88x920.9% strain amount, and which has, at a 940 xcexcm-device length and 150 mA injection current, a below 1.0 dB inter-polarization gain difference, a 23 dB fiber to fiber gain and a +7.0 dBm chip out saturation power (a +3.5 dBm fiber out saturation power) (see, e.g., A. Ougazzaden et al., Electron. Lett., vol. 31, pp. 1242-1244, 1955, D. Sigogne et al., ECOC95, pp. 267-270, and D. Sigogne et al., Electron. Lett., vol. 32, pp. 1403-1405, 1996).
As a semiconductor optical amplifier using a tensile strained bulk active layer, J. Y. Emery et al., Alcatel realized a device which includes a 200 nm-thick bulk active layer sandwiched on both sides thereof by 100 nm-separate confinement heterostructure layers and having a xe2x88x920.15% tensile strain at a 1.2 xcexcm-active layer width, and which has, at a 1000 xcexcm-device length and 200 mA injection current, a below 0.3 dB inter-polarization gain difference, a 29 dB fiber to fiber gain and a +9.5 dBm fiber out saturation power (see, e.g., J. Y. Emery et al., ECCO96, vol. 3, pp. 165-168 and J. Y. Emery et al., Electron. Lett., vol. 33, pp. 1083-1084, 1997).
Polarization independent-type semiconductor optical amplifiers of various active layer structures as described above have been studied. In such semiconductor optical amplifiers, in order to obtain a wide dynamic range it is required that a fiber out saturation power, which provides an upper limit of the dynamic range, is as large as possible. For example, for a semiconductor optical amplifier for 1.55 xcexcm-band having polarization dependency, the MQW active layer structure can provide a +19.5 dBm chip out saturation power.
However, in the polarization independent-type semiconductor optical amplifier for 1.55 xcexcm-band, even a maximum fiber out saturation power cannot exceed +9.5 dBm obtained by using the tensile strained bulk active layer of the above-described J. Y. Emery et al., Alcatel. The optical amplifier is inferior to the polarization dependent-type optical amplifier by even 7.5 dB, taking into account a 2.5 dB fiber coupling loss.
A cause for such low fiber out saturation powers of the polarization independent-type semiconductor optical amplifiers is that structural restrictions of the active layers imposed for the optical amplifiers to be polarization independent hinders high out saturation power.
In the case that the strain-free bulk active layer is used as in P. Doussiere et al., Alcatel, the active layer has rectangular section for making the optical confinement in the active layer polarization-independent. The lower limit of dimensions of the section of the active layer is 300 nm-square due to fabrication limitations. The upper limit is restricted to 600 nm-square due to conditions for maintaining fundamental modes. Freedom of design of the device is low.
In the case that the strained MQW layer is used, in order to nullify increased material gain for TE polarization light in the active layer due to the quantum effect and increased optical confinement for TE polarization light in the flat active layer, a large tensile strain must be used for increased material gain for TM polarization light.
However, in the case that such large tensile strain is used, because a gain peak wavelength is made shorter by both quantum effect and tensile strain effect, and also by band filling effect due to injection current increase, in order to obtain a necessary gain near a 1.55 xcexcm-wavelength, a restriction that tensile strain is applied to the barrier layer, or the quantum well layer is made thick to depress the shortening of the wavelength due to the quantum effect is applied. Accordingly, a problem is that freedom of structural design for obtaining large fiber out saturation powers is much decreased.
Here, with reference to FIG. 14, the conventional polarization independent-type semiconductor optical amplifier using the tensile strained bulk active layer of Alcatel will be explained.
FIG. 14 is a diagrammatic perspective view of the conventional polarization independent-type semiconductor optical amplifier. In the forward half portion of the semiconductor optical amplifier, a p-type InP buried layer 37, proton-injection regions 38, 39, a p-type InGaAs contact layer 40 and a p-side electrode 42 are not shown so as to show the structure of the active layer. A spot size conversion region, a window region, etc., are left out of FIG. 14.
In this polarization independent-type semiconductor optical amplifier, 100 nm-thick InGaAsP separate confinement heterostructure layers (SCH layers) 33, 35 are provided on and the underside of a 200 nm-thick InGaAsP strained bulk active layer 34, and a stripe width is 1.2 xcexcm.
The optical axis of the striped InGaAsP strained bulk active layer 34 intersects at a 7xc2x0 inclination angle, a normal of the light input/output end faces.
This optical amplifier is so designed that the active layer which is as thick as 200 nm is used to make an optical confinement ratio between TE and TM polarization lights (TE/TM) small, whereby a required tensile strain is depressed to be as low as xe2x88x920.15%. Resultantly, an inter-polarization gain difference can be small, whereby a signal input light 46 entering at one end face is amplified independent of polarization to be outputted as amplified output light 47.
Antireflection coating films (AR films) 44, 45 are provided on both end faces for suppressing resonance of the signal input light 46.
However, as described above, the polarization independent-type semiconductor optical amplifier using this tensile strained bulk active layer has a +9.5 dBm fiber out saturation power. This fiber out saturation power is still considerable low, even taking into account fiber coupling loss of 2.5 dB, in comparison with a +19.5 dBm chip out saturation power of a polarization dependent-type semiconductor optical amplifier.
In this polarization independent-type semiconductor optical amplifier using tensile strained bulk active layer, the tensile strained bulk active layer still has not a critical film thickness for strain relaxation, and accordingly a larger strain can be applied. Accordingly, the active layer structure is changed to thereby increase the chip out saturation power, whereby the fiber out saturation power can be increased.
An object of the present invention is to obtain increased fiber out saturation power without lessening structure design freedom, by making no inter-polarization gain difference while increasing output saturation power.
Means for achieving the object of the present invention will be explained with reference to FIGS. 1A and 1B. FIG. 1A is an upper side view, and FIG. 1B is a diagrammatic sectional view which is normal to the optical axis. In the drawings, reference numbers 1 and 6 represent a clad layer, reference number 4 indicates a striped mesa, and reference number 5 denotes a buried layer.
The polarization independent-type semiconductor optical amplifier according to the present invention is characterized in that the polarization independent-type semiconductor optical amplifier comprises: a strained bulk active layer 3 of a bulk crystal having a tensile strain introduced into, resonance of light due to reflection between a light incident end face 7 and a light exit end face 8 being depressed, an optical signal 9 being incident on the light incident end face 7, current being injected into the strained bulk active layer 3 to amplify the optical signal 9 by a stimulated emission effect, the amplified signal 10 exiting at the light exit end face 8, and a signal transmission gain of the amplified signal 10 being substantially constant, independent of a polarized state of the incident optical signal 9, in which a thickness of the strained bulk active layer 3 is 20 nmxcx9c200 nm, and a strain amount is xe2x88x920.09% xcx9cxe2x88x920.60%.
Thus, the strained bulk active layer 3 forming the polarization independent-type semiconductor optical amplifier has a thickness d of 20 nmxcx9c100 nm and a strain amount of xe2x88x920.09%xcx9cxe2x88x920.60%, whereby large output saturation power can be provided while polarization independence being retained.
That is, generally an output saturation power Ps of a semiconductor optical amplifier is expressed by
Ps=(wxc3x97d/xcex93)xc3x97hv/(xcfx84xc3x97a)
where a thickness of the strained bulk active layer 3 is d, a confinement factor is xcex93, a photon energy is hv, a carrier lifetime is xcfx84, and a differential gain is a. A thickness d of the strained bulk active layer 3 is made small to make a confinement factor xcex93 small, whereby a large mode cross section (wxc3x97d/xcex93) is provided while, in addition, the effect of a higher carrier density reducing a carrier lifetime xcfx84 is provided, so as to provide a larger output saturation power.
On the other hand, the strained bulk active layer 3 is thinned and has a sectional configuration of higher flatness, whereby an optical confinement ratio between TE and TM polarization lights is high, and a required strain amount is larger. However, when the strained bulk active layer 3 has a thickness of 20 nmxcx9c100 nm, a strain amount is set to be xe2x88x920.09%xcx9cxe2x88x920.60%, whereby polarization independence can be retained.
When a thick strained bulk active layer 3 is sandwiched by thick separate confinement heterostructure layers 2, the optical confinement ratio between TE and TM polarization lights become smaller, whereby the strain amount required for polarization independence become smaller. In a case that the thickness of the strained bulk active layer 3 is 100 nm, in consideration of directing conditions of fundamental mode in a case that a stripe width is above 1 xcexcm, it is possible that the strained bulk active layer 3 is sandwiched by the separate confinement heterostructure layers 2 of a 300 nm-thick and of a 1.2 xcexcm composition (xcexg=1.2 xcexcm). In this case, the strain amount of the strained bulk active layer 3 required for the polarization independence is xe2x88x920.09%.
When a thin strained bulk active layer 3 is not sandwiched by separate confinement heterostructure layers 2, the optical confinement ratio between TE and TM polarization lights increases, whereby the strain amount required for polarization independence increases. In a case that the thickness of the strained bulk active layer 3 is 20 nm, the strain amount of the strained bulk active layer 3 required for the polarization independence is xe2x88x920.60% when the strained bulk active layer 3 is not sandwiched by the separate confinement heterostructure layers 2.
As will be described later, an upper limit of the thickness of the strained bulk active layer 3 is set to be about 90 nm or about 80 nm, whereby better output saturation power can be provided. A lower limit of the strain amount in the case that a thickness of the strained active layer 3 is 90 nm is xe2x88x920.10%, and in a case that a thickness of the strained active layer 3 is 80 nm, a lower limit of the strain amount is xe2x88x920.11%.
One measure of a lower limit of the strained bulk active layer thickness is considered to be about 20 nm, because when the strained bulk active layer 3 is thinned, and the quantum effect is conspicuous, a material gain for TE polarization light is large.
As will be described later, a lower limit of the thickness of the strained bulk active layer 3 is set to be about 25 nm or about 30 nm, the quantum effect can be effectively depressed. A upper limit of the strain amount in the case that a thickness of the strained active layer 3 is 25 nm is xe2x88x920.45%, and in a case that a thickness of the strained active layer 3 is 30 nm, a upper limit of the strain amount is xe2x88x920.44%.
The present invention is also characterized in that, in the above-described polarization independent-type semiconductor optical amplifier, the strained bulk active layer is sandwiched by separate confinement heterostructure layers 2 disposed in a direction of thickness of the strained bulk active layer 3 and in contact with the strained bulk layer 3.
Thus, the strained bulk active layer 3 is sandwiched by the separate confinement heterostructure (SCH) layers 2, whereby a smaller optical confinement ratio between TE and TM polarization lights and a larger mode cross section (wxc3x97d/xcex93) can be provided.
In this case, an optical axial direction of the strained bulk active layer 3 is inclined by 7-10xc2x0 to a normal of the light exit end face 8, whereby light resonance due to reflection between the light incident end face 7 and the light exit end face 8 can be depressed. The semiconductor optical amplifier can be free generation of ripples in outputs.
In this case, it is preferable that a width of the strained bulk active layer 3 is tapered to gradually reduce the width at a ratio of above 1/1000 per a unit length toward the light exit end face 8 from the center of the device, whereby optical coupling efficiency with an optical system, such as optical fibers, etc. is improved.
When a 1.0 xcexcm-width is reduced to a 0.6 xcexcm-width over a 400 xcexcm-length, the ratio is 1/1000 ((1.0 xcexcm-0.6 xcexcm)/400 xcexcm).
Otherwise, it is possible that a thickness of the strained bulk active layer is tapered gradually toward the light exit end face 8 from the center of the device so that a thickness of the strained bulk active layer 3 at the end on the light exit end face 8 is below xc2xd of a thickness thereof at the center of the device. Higher optical coupling with an optical system, such as optical fibers can be provided.
It is preferable that the so-called window structure, in which the strained bulk active layer 3 is absent, but the clad layer is present, is provided over 20-50 xcexcm from the light exit end face 8 on the light exit end face 8. Reflection of signal light 9 on the light exit end face 8 can be prevented, whereby generation of ripples in amplified signal light 10 can be prevented without failure.


An image forming apparatus having a development apparatus that includes: a developer storing part; a developer supply mechanism; and a surplus developer removing section; wherein the developer supply mechanism includes: a toner storing part; a carrier storing part; a developer conveying path and a conveying mechanism, both are arranged between the toner storing part and the developer storing part, and between the carrier storing part and the developer storing part; wherein the developer conveying path includes a toner ejection outlet through which a toner stored in the toner storing part is ejected and a carrier ejection outlet through which a carrier stored in the carrier storing part is ejected, and a supplying developer ejection outlet through which a supplying developer is ejected to the developer storing part; and wherein the conveying mechanism is adapted to convey the toner and the carrier while stirring them.

1. Field of the Invention
The present invention relates to an image forming apparatus of an electrophotographic process applying development by use of a two-component developer.
2. Description of Related Art
As an image forming apparatus of an electrophotographic process, heretofore, known is an image forming apparatus mounted with a developing apparatus of a so-called trickle development process, in which a two-component developer comprising a toner and a carrier (hereinafter, also referred to as simply "a developer") is utilized, a toner triboelectrically charged by stirring with a carrier being conveyed to a development region, a toner image being formed by making a toner adhere on an electrostatic latent image formed on an image carrier, and further a used developer is gradually removed as well as an unused toner and carrier are continuously or intermittently supplied.
Generally, a two-component developer receives a stress due to a stirring motion to make additives such as a lubricant having been added on the surface of toner particles constituting a toner release from or contrary be buried into toner particles, as a result, charging ability of a developer may be deteriorated to decrease the charge amount of a toner, or fluidity of a developer may be decreased to make coefficient of friction between a carrier and a toner high to cause a phenomenon of carrier contamination due to adhesion of a toner on a carrier; however, excessive deterioration of a developer is restrained because a unused toner is continuously or intermittently supplied as well as additives will be also supplied thereby by adopting such a trickle development process. Herein, it is difficult to make additives uniformly contact with a toner and a carrier even when additives are independently supplied as they are into a development apparatus.
However, in such a trickle development process, since a toner and a carrier are stored in the same vessel in advance and a carrier is supplied according to supply control of a toner, there is a problem that a supply amount of a carrier cannot be directly controlled. Therefore, a supply amount of a carrier varies corresponding to a printing ratio (hereinafter, referred to as "a coverage") of an original. That is, since a toner amount supplied for image formation is large in the case of continuously printing an original having a high coverage, there is a problem that a supply amount of a carrier which is supplied simultaneously with toner supply becomes large to increase CCP (Cost Per Print: a cost per one sheet of printing paper). Further, in the case of continuously printing an original having a low coverage, since the amount of a toner supplied for image formation is very small, the supply amount of a carrier supplied simultaneously with toner supply also decreases to decrease a removal amount of a developer, which decreases an exchange amount of a carrier resulting in deterioration of a carrier, there is a problem of generation of image deterioration such as fogging and a toner scattering due to decrease of fluidity and charging ability of a developer.
To solve the above-described problems, technologies such as disclosed in JP-A 9-204105 (hereinafter, JP-A refers to Japanese Patent Publication Open to Public Inspection No.), JP-A 10-63074 and JP-A 2006-71859 are proposed.
In 2-A 9-204105 and JP-A 10-63074, as shown in FIG. 11, proposed is an image forming apparatus equipped with development apparatus 50 which supplies a toner stored in toner storing part 51 and a carrier stored in carrier storing part 52 to developer storing part 53 while independently controlling their supply amounts. In such an image forming apparatus, although a supply amount of a carrier can be directly controlled, sufficient triboelectric charging of a toner by stirring with a carrier cannot be obtained because a toner and a carrier are supplied into developer storing part 53 without being mixed or stirred in advance, which causes scatter of a charging amount between a toner supplied and a toner stored in development storing part 53 to make charging amount distribution of a toner broad, whereby there is a problem of generation of image deterioration such as fogging.
Further, in JP-A 2006-71859, proposed is an image forming apparatus equipped with development apparatus 60 in which a toner stored in toner storing part 61 and a carrier stored in carrier storing part 62 are temporarily stored in intermediate tank 64 while independently controlling the supply amounts, and a toner and a carrier are stirred while being circulated in this intermediate tank 64 to be supplied to developer storing part 63 as a supplying developer. However, in this image forming apparatus, it is difficult to rapidly supply a supplying developer of a varying trickle rate (a carrier concentration of a supplying developer) to developer storing part 63 unless the whole of a supplying developer stored in intermediate tank 64 is removed. Therefore, since supply control of a carrier cannot be minutely performed, supplying response of a carrier is insufficient and increase of CCP and deterioration of a carrier cannot be sufficiently dissolved. Further, there is also a problem that an apparatus inevitably becomes big due to installation of intermediate tank 64.
This invention has been made in view of the above-described problems, and the object is to provide an image forming apparatus which exhibits sharp charging amount distribution of a toner, restrains deterioration of a developer because of excellent supplying response of an adequate amount of a toner and a carrier, and enables to stably form high quality images for a long term.

Konica Minolta Business Technologies, Inc.


The present invention relates to a system for dynamometer testing of motor vehicles. The system includes a cooling device for cooling a braking device and/or a power-generating arrangement, such as the engine of a car. The system is arranged to, using the braking device, absorb power applied thereto by the power-generating arrangement. The cooling device includes a fan arrangement for producing an air stream, the air stream being intended to be directed towards the braking device and/or the power-generating arrangement and/or a heat exchanger for providing a cooling effect. The fan arrangement includes two substantially axially aligned fans, and the cooling device is arranged to rotate the fans in opposite directions relative to each other. The present invention also relates to a method.

This invention relates in particular to devices for dynamometer testing of motor vehicles, that is, devices which are adapted to be connected to a driven vehicle output shaft and which include means for measuring one or more quantities significant to the performance of the engine and the transmission, such as the torque that the driven shaft applies to a power-absorbing device forming part of the test device.
One such device is disclosed in EP 0 210 979, which discloses a device including power-absorbing means in the form of a hydraulic pump assembly which has an input shaft adapted to be in engagement with a driven vehicle shaft using a rigid coupling. The pump assembly consists of two pumps, which are drivingly interconnected and thereby both driven by the shaft. An adjustable control valve is controlled such that the valve allows the passage of a liquid flow, the volumetric rate of which being related to the desired rotational speed of the rotor, i.e. of the driven vehicle shaft. By controlling the working pressure of the pumps, a desired torque can be applied to the drive shaft of the vehicle, and, thereby, the performance of the engine can be tested.
A problem with this device, however, is that as vehicle engines increasingly tend to generate higher and higher powers, and higher and higher torques, the heat generated by the power-absorbing means when testing these engines, e.g., as a temperature rise of the hydraulic fluid when passing through the control valve, becomes more difficult to cool.

System and method for dynamometer testing of motor vehicles, including a cooling device


The present invention relates to methods and compositions for modifying peptides, polypeptides and proteins with polymers, especially glyco-mimetic polymers, so as to improve their biological activity or pharmacokinetic properties. The invention further provides methods and uses for such polymer-modified peptides, polypeptides and proteins. The invention is particularly suitable for use in the synthesis of polymer-modified synthetic bioactive proteins (FIG. 1D), and of pharmaceutical compositions that contain such proteins.

Over the past 30 years, medical attention has increasingly turned to the possibility of using proteins as therapeutic drugs for the treatment of disease (See, e.g., "Therapeutic Proteins 1999," Datamonitor plc, London, 1999). Most protein therapeutics are based on naturally occurring animal or human forms of the protein (such as insulin, growth hormone, erythropoietin, interleukin-2 etc.) and produced in recombinant DNA engineered bacterial or eukaryotic cells. Unfortunately, recombinant proteins made in bacterial cells, such as E. coli, often lack post-translational modifications that are normally found in the protein's naturally produced form. This lack of modification can have a significant negative impact on the pharmaceutical properties of the protein when introduced to a patient.
Glycosylation is one example of a common post-translational modification in eukaryotes that involves the enzymatic attachment of complex sugar chains to the protein. Because recombinant proteins made in bacterial expression systems lack the ability to glycosylate proteins, eukaryotic expression systems such as plant, yeast, insect or mammalian cells have been used in their place when a glycosylated form or 'glycoprotein' is required. A significant problem in making recombinant glycoproteins is that the resulting product typically consists of a complex mixture of different 'glycoforms', which may have widely varying physiological or pharmacological properties.
Nevertheless, recombinant DNA techniques have become the primary method for commercial production of many polypeptides and proteins because of the large quantities that can be produced in bacteria and other host cells. Recombinant protein production involves transfecting or transforming host cells with DNA encoding the desired exogenous protein and growing the cells under conditions favoring expression of the recombinant protein. E. coli and yeast are favored as hosts because they can be made to produce recombinant proteins at high titers (see, U.S. Pat. No. 5,756,672).
Numerous U.S. patents have been issued with respect to general bacterial expression of recombinant-DNA-encoded proteins (see, for example, U.S. Pat. Nos. 4,565,785; 4,673,641; 4,738,921; 4,795,706; 4,710,473). Unfortunately, the use of recombinant DNA techniques has not been universally successful. Under some conditions, certain heterologous proteins expressed in large quantities from bacterial hosts are precipitated within the cells in dense aggregates, recognized as bright spots visible within the enclosure of the cells under a phase-contrast microscope. These aggregates of precipitated proteins are referred to as "retractile bodies," and can constitute a significant portion of the total cell protein (Brems et al., Biochemistry (1985)24: 7662.
Recovery of protein from these bodies has presented numerous problems, such as how to separate the protein encased within the cell from the cellular material and proteins harboring it, and how to recover the inclusion body protein in biologically active form. For general review articles on refractile bodies, see Marston, supra; Mitraki and King, Bio/Technology, 7:690 (1989); Marston and Hartley, Methods in Enzymol., 182: 264–276 (1990); Wetzel, "Protein Aggregation In Vivo: Bacterial Inclusion Bodies and Mammalian Amyloid," in Stability of Protein Pharmaceuticals: In Vivo Pathways of Degradation and Strategies for Protein Stabilization, Ahern and Manning (eds.) (Plenum Press, 1991); and Wetzel, "Enhanced Folding and Stabilization of Proteins by Suppression of Aggregation In Vitro and In Vivo," in Protein Engineering—A Practical Approach, Rees, A. R. et al. (eds.) (IRL Press at Oxford University Press, Oxford, 1991).
Proteins also have been produced as research reagents by total chemical synthesis (See, e.g., Wilkin et al., Curr. Opinion Biotech. (1999) 9:412–426). This process involves chemical synthesis of proteins by the stepwise coupling of individual amino acids, or convergent strategies that employ the separate synthesis of peptide or polypeptide segments followed by linking of the segments, including chemical ligation of such segments, to generate full-length products (See, e.g., Dawson et al., Ann. Rev. Biochem (2000) 69:923–960). In some instances chemical synthesis has been utilized to make small glycoproteins modified with simple low molecular weight sugars (Shin et al., J. Am. Chem. Soc. (1999) 121:11684–11689). In other cases, proteins have been made chemically to contain detectable labels and the like (Bolin et al., FEBS Letters (1999) 451:125–131). Unfortunately, such labeled proteins offer little to no therapeutic advantage over their recombinantly produced counterparts. However, a few proteins showing therapeutic potential have been made by chemical synthesis with a focus on improving potency by use of small molecule-type changes to pharmacophore regions of the target protein (U.S. Pat. No. 6,168,784). While potency is an important aspect in making a therapeutic, other factors remain problems with protein therapeutics.
Efforts to develop therapeutically usable protein drugs have long suffered from the undesirable bioactivity, bioavailability and biokinetics (such as clearing time, etc.) of putative drug candidates upon in vivo administration. The principal factors that have severely limited the use of proteins, and of polypeptides in particular, as therapeutic agents has been the fact that these compounds often elicit an immunogenic response in the circulatory system (see, U.S. Pat. No. 4,179,337 (Davis et al.)). This effect has one or both of two secondary consequences. The first being the destruction of polypeptides by the elicited antibodies, and the second more seriously, being the emergence of an allergic response. For example, the antibody-mediated destruction of insulin is believed to be responsible for the rather low residence time of insulin in the human circulatory system. In the case of enzymes, not only is there a problem of destruction of the polypeptide and the subsequent negation of its physiological activity but also the most undesired elicitation of an allergic reaction. Conversely, certain proteins, such as clotting factors, growth factors and cytokines, etc., may exhibit a biological half-life that is disadvantageously prolonged upon their in vivo administration.
One approach to improving proteins for use as therapeutics has involved derivatizing the protein with water-soluble polymers. Such conjugation has been proposed as a means for improving the circulating life, water solubility or antigenicity of administered proteins, in vivo (see, U.S. Pat. No. 4,179,337 Davis et al.). Many different water-soluble polymers and attachment chemistries have been used towards this goal, such as polyethylene glycol, copolymers of ethylene glycol/propylene glycol, carboxymethylcellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone, poly-1, 3-dioxolane, poly-1,3,6-trioxane, ethylene/maleic anhydride copolymer, polyaminoacids (either homopolymers or random copolymers) and the like. Polyethylene glycol ("PEG") is one such chemical moiety that has been used in efforts to obtain therapeutically usable proteins (Zalipsky, S. (Bioconjugate Chemistry (1995) 6:150–165; Mehvar, R. (J. Pharm. Pharmaceut. Sci. (2000) 3(1):125–136)). Its backbone (CH2CH2O)n is flexible, amphiphilic, not susceptible to proteases, and non-immunogenic. Attachment of PEG also has been shown to protect proteins against proteolysis (Blomhoff, H. K. et al., Biochim Biophys Acta (1983) 757:202–208). It also can improve other physical-chemical properties of proteins.
For example, pegademase bovine (Adagen®), a formulation of adenosine deaminase with an attached PEG polymer, has been developed for treating severe combined immunodeficiency disease (SCID); superoxide dismutase with an attached PEG moiety has been in clinical trials for treating head injury; alpha interferon with an attached PEG moiety has been tested for treating hepatitis. Pegylated IL-6 has been described (see, EP 0 442 724, and U.S. Pat. No. 5,264,209). EP 0 154 316 reports reacting a lymphokine with an aldehyde of polyethylene glycol. European Patent Publication EP 0 401 384, describes materials and methods for preparing granulocyte colony stimulating factor ("G-CSF") to which polyethylene glycol molecules are attached. Modified G-CSF and analogs thereof are also reported in EP 0 473 268, stating the use of various G-CSF and derivatives covalently conjugated to a water-soluble particle polymer, such as polyethylene glycol. U.S. Pat. No. 5,880,255 summarizes many of the proteins that have been modified with PEG chains.
A variety of means have been used to attach polymer moieties such as PEG and related polymers to reactive groups found on the protein (see, U.S. Pat. No. 4,179,337 (Davis et al.), and U.S. Pat. No. 4,002,531 (Royer). For a review, see Abuchowski et al., in "Enzymes as Drugs," (J. S. Holcerberg and J. Roberts, eds. pp. 367–383 (1981) and Zalipsky, S. (Bioconjugate Chemistry (1995) 6:150–165. The use of PEG and other polymers to modify proteins also is discussed by Cheng, T.-L. et al., Bioconjugate Chem. (1999) 10:520–528; Belcheva, N. et al., Bioconjugate Chem. (1999) 10: 932–937; Bettinger, T. et al., Bioconjugate Chem. (1998) 9:842–846; Huang, S.-Y. et al., Bioconjugate Chem. (1998) 9:612–617; Xu, B. et al. Langmuir (1997) 13:2447–2456; Schwarz, J. B. et al., J. Amer. Chem. Soc. (1999) 121:2662–2673; Reuter, J. D. et al., Bioconjugate Chem. (1999) 10:271–278; Chan, T.-H. et al., J. Org. Chem. (1997) 62:3500–3504. Typical attachment sites in proteins include primary amino groups, such as those on lysine residues or at the N-terminus, thiol groups, such as those on cysteine side-chains, and carboxyl groups, such as those on glutamate or aspartate residues or at the C-terminus. Some of the most common sites of attachment are to the sugar residues of glycoproteins, cysteines or to the N-terminus and lysines of the target proteins.
Although many different approaches have been described for conjugation of polymers to proteins, the conjugation process is not without complications. Care must be taken to limit the loss of biological activity caused by the conjugation reaction. For example, folded or re-folded proteins are typically used to minimize the number of sites of attachment. However, if too much of the activated polymer is attached to the target protein or polypeptide, biological activity can be severely reduced or lost. Likewise, if the wrong linker joining the polymer to the protein is used or an insufficient amount of polymer is attached to the target, the therapeutic value of the resultant conjugate may be limited, and may not demonstrate enough of an increase in circulating life to compensate for the loss in its bioactivity. Problems can also result due to a blockage of the protein's active site by the modifying polymer. This problem can be difficult to avoid since the polymer and protein are typically joined in solution-based reactions. Pre-blocking the active sites with materials such as pyridoxal phosphate has been suggested, but the results have been inconsistent (see, U.S. Pat. No. 4,179,337 (Davis et al.)). These problems are particularly acute with lower molecular weight proteins and peptides, which often have few attachment sites not associated with bioactivity.
For instance, a common technique has been the attachment of water-soluble polymers to the primary amines in the target protein (e.g., the N-terminal amino group and the epsilon amino groups of lysines). Thiol-reactive polymer conjugates also have been used to attach polymers to the thiol side-chains of cysteines. Both approaches represent significant problems as most proteins contain multiple copies of such reactive groups spread out over various regions of the polypeptide backbone that play an important role in defining the activity, folding, re-folding and stability of a protein. Thus although widely used, such approaches suffer from more or less incomplete or unwanted reduction in bioactivity of a protein, and usually complex mixtures that are difficult to separate and characterize (Delgada et al., Pharmaceutical Sciences (1997) 3:59–66).
In an attempt to reduce random attachment, proteins have been made in which the natural lysines are removed in conjunction with adding lysines at the desired sites of polymer attachment (U.S. Pat. No. 4,904,584). For example G-CSF and IL-2 have been modified in this manner. Other attempts to avoid random attachment has been to make proteins in which the natural cysteines are removed in conjunction with adding cysteines at the desired sites of polymer attachment, or cysteines are added without removing the natural cysteines if present (EP 0 668 353). For example, G-CSF, IL-3 and EPO have been made this way. While such cysteine or lysine variants theoretically allow site-specific polymer attachment, there still is no guarantee that all selected sites can be modified in a controlled manner.
Given the inability to site-specifically modify proteins containing multiple amino acids with side-chains bearing the same or similar reactive functional groups, recent efforts have focused on the modification of the amino or carboxy terminus of proteins. Modification of the amino or carboxy terminus has relied on the ability of some chemical conjugation techniques to uniquely modify these sites (WO 90/02136 and WO 90/02135). For example, this technique was utilized for the attachment of PEG chains to the N-terminal residue of G-CSF and the chemokine IL-8 (Gaertner et al., Bioconjug. Chem. (1996) 7(1):38–44; and WO 96/41813). However, modification of the N- or C-termini typically reduces a protein's activity (See, e.g., U.S. Pat. No. 5,985,265 discussing attachment of PEG to the N-terminus and lysine side chains of G-CSF). Despite the drawbacks with modification of proteins with water-soluble polymers, PEGylation and attachment of other water-soluble polymers to proteins continues to be pursued. For example, attachment of PEG to histidine in IF-alpha has been described in U.S. Pat. Nos. 5,951,974 and 6,042,822. Attachment of PEG to lysines in alpha interferon is described in U.S. Pat. No. 5,595,732. Attachment of PEG to sugar chains of erythropoietin (EPO) and internal amino acids such as lysines (EP 0 605 963 and WO 00/32772), and the N-terminus (U.S. Pat. No. 6,077,939 and WO 00/32772) also has been described.
Another problem is that all of the above-discussed polymers are highly non-homogeneous, which render analytical characterization and purification of the mixtures of polymer-modified proteins difficult (Delgada et al., Pharmaceutical Sciences (1997) 3:59–66). For example, techniques used to prepare PEG or PEG-based chains, even those of fairly low relative molecular mass such as 3400, involve a poorly controlled polymerization step which leads to preparations having a spread of chain lengths about a mean value; that is, they involve polymer preparations of (CH2CH2O)n where n does not have a discrete value but rather has a range of values about a mean. The resulting heterogeneity of the derivatized proteins is often associated with a range of properties that one cannot easily identify much less separate. Although the use of polypeptide adducts might be considered to offer a possible solution in principle, the use of polypeptides is disadvantageous since they are susceptible to proteolytic cleavage and can render the derivatized protein immunogenic.
Unfortunately, however, the problem of identifying and employing a suitable polymer is exacerbated by the fact that all proteins currently employed for therapeutic use are derived from recombinant DNA technologies. The use of recombinant DNA technologies puts severe limitations on the types and specificity of linkages that can be formed between a performance-enhancing moiety and the recombinantly produced protein. This is because firstly there are only a very limited number of functional groups suitable for linkage, and secondly there will generally be several copies of the reactive functional group in the protein being modified, thus precluding any specificity of modification. For example, it has been shown that in the case of nonselective conjugation of superoxide dismutase with PEG, several fractions of the modified enzyme were completely inactive (P. McGoff et al., Chem. Pharm. Bull. (1988) 36:3079–3091). Also, if differing numbers of such moieties are randomly attached, the pharmacokinetics of the therapeutic protein cannot be precisely predictable, making dosing a large problem. The lack of control of attachment furthermore may lead to (a) reduced potency, (b) a need for elaborate purification schemes to separate a vast mixture of derivatives and (c) possibly unstable attachment of the modifying moiety. Several linkages, such as tresylchloride-based linkages, known to the art are also known to be immunogenic.
Thus to improve circulating half-life, reduce proteolysis and immunogenicity and improve other properties of biologically produced proteins, water-soluble polymers such as PEG can be attached, but with mixed results given the difficulty of attaching them in a controlled manner and with user-defined precision. Also, because of the limited success in attaching polymers at precise user-defined sites, very little is known about preferred sites of attachment that could be applicable to proteins in general. In addition, because of the stochastic nature of attachment, and the hetero-disperse nature of PEG and other water-soluble polymers currently employed for such purposes, purification and analytical characterization of PEG-protein conjugates has been difficult. Thus the combined problem of poor control over reproducible attachment and polymer heterogeneity has severely hampered the routine approval of polymer-modified proteins as therapeutics (only a few approved to date for therapeutic use despite its introduction in the early 1970's).
Accordingly, a need exists for methods of forming bioactive proteins that are distinct from recombinant DNA technologies, and that could be used to form proteins capable of polymer modification. A need also exists for a preferred polymer that can be employed to form derivatized proteins that have polymer adducts of defined structure rather than a mixture of chains of different lengths. Polymers that can be employed to form derivatized proteins having polymer adducts with structures that can be tailored to mimic desirable properties of natural proteins also is needed. Moreover, a need exists for derivatizing proteins that has general applicability to many proteins. The present invention satisfies these and other needs.


Simple, economical preparative processes for the provision of pure hydroxyl functional materials derived by converting unsaturated molecules found in animal fats into hydroxyl groups are presented herein. The hydroxylated animal fats can be reacted with isocyanates to form polyurethane articles.

Polyols are preferred compounds in polymer chemistry, due to their multiple hydroxyl functional groups available for organic reactions. Polymeric polyols react with isocyanates to form polyurethanes. Additionally, some polyols may be classified as polyether polyols, which are made by reacting epoxides with an active hydrogen containing starter compounds. These may also react with isocyanates to form polyurethanes. Polyurethanes have a number of commercial applications, including foams, potting compounds, cast resins, coatings, elastomers, adhesives, sealants, non-reinforced and fiber reinforced plastics processed using resin transfer molding (RTM), and reaction injection molding (RIM), filament winding, and pultrusion techniques.
Soybean oil can be converted to hydroxy functional soybean oil. The addition of hydroxy functionality is typically accomplished by adding hydroxyl groups (—OH) to the carbons. These polyols are then used as reactants to make polymers. The hydroxyl functional groups in polyols can be reacted with isocyanates to make polyurethanes.

Methods of preparing hydroxy functional animal fats


An integrated circuit like a programmable logic device (“PLD”) includes a communication channel employing 8B/10B coding. Disparity information determined by 8B/10B decoder circuitry in the communication channel is supplied to other circuitry of the PLD so that any requirement for disparity to have a particular value in conjunction with certain received codes can be checked. On the transmitter side, circuitry is provided for selectively forcing the 8B/10B encoder to use a commanded disparity (which can be either positive or negative) under particular circumstances.

This invention relates to integrated circuits such as programmable logic devices ("PLDs"), and more particularly to serial data signal interface or transceiver circuitry for use on PLDs or similar circuitry.
There is increasing interest in using high-speed serial data signals for communication between various devices in systems. For example, the devices in a system may be various integrated circuits that are mounted on a printed circuit board ("PCB"). The high-speed serial communication between the devices in such a system may take place via circuit traces on the PCB. One or more of the devices may be a PLD or that general type of relatively general-purpose, programmable or configurable device. All such devices to which the invention can be applied may sometimes be referred to generically as PLDs. This terminology is employed solely for convenience and is not intended to limit the invention to any particular narrow class of devices.
There are many communication protocols that are known for use in high-speed serial data communication. It is desirable for a PLD (which is intended to be a relatively general-purpose device) to be useful in a number of different possible applications. Indeed, as a general matter, the more possible uses a PLD can satisfy, the better (e.g., because it increases the market for that PLD product). For example, it may be desirable to provide a PLD that can support many different high-speed serial data communication protocols. Those protocols may include industry-standard protocols and protocols that a user may design on a customized basis.
High-speed serial data communication may be supported on a PLD by including on the PLD some circuitry that is dedicated to performing certain tasks associated with such communication. Such dedicated circuitry may be referred to as "hard IP" (IP being an acronym for intellectual property). The hard IP circuitry may be controllable, programmable, or configurable in some respects to adapt or customize it to particular communication protocols. Hard IP (rather than the general-purpose logic of the PLD) may be used for some aspects of high-speed serial communication for any of several reasons. These may include the need to provide higher-speed circuitry to keep up with the extremely fast bit rates of the serial communication, the large number of general-purpose logic elements that would be required to perform some of the complex encoding/decoding tasks required for some high-speed serial communication protocols, etc. Other parts of the communication task can be performed by other parts of the PLD circuitry (e.g., the so-called media access control ("MAC") layer of the PLD and/or the general-purpose programmable logic of the PLD).
Many high-speed serial communication protocols use a coding scheme known as 8-bit/10-bit or 8B/10B coding. See Franaszek et al. U.S. Pat. No. 4,486,739, which is hereby incorporated by reference herein in its entirety. Although there is a basic 8B/10B scheme, different communication protocols may use that scheme in somewhat different ways. It is desirable for a PLD to include circuitry that supports these different versions of use of 8B/10B coding so that the PLD can be used to support a wide range of communication protocols employing such coding.

Circuitry for providing configurable running disparity enforcement in 8B/10B encoding and error detection


A multifunctional camera system having a bendable arm configured to be inserted into the thoracic cavity of a patient and camera head at a distal end of the bendable arm. The camera head has a high definition video camera and a light source. The camera head has a view adjustment mechanism for changing a view angle of the camera without changing the position of the camera head. A controller controls the view adjustment mechanism under command of a surgeon.

Video-assisted thoracoscopic surgery (VATS) is a type of thoracic surgery performed with the assistance of a small video camera that is introduced into the patient's chest, via one or more small incisions made specifically to introduce the camera or via a common opening through which surgical tools are also introduced. The camera allows the surgeon to view the instruments that are being used along with the anatomy on which the surgeon is operating. Most commonly, the camera and instruments are inserted through separate, 10 mm to 30 mm holes or "ports" in the chest wall. The small size of these ports corresponds with reduced prevalence of infection and wound dehiscence for VATS patients as compared to those subjected to thoracotomy, sternotomy, or other approaches that require large incisions to provide direct visual access to the surgeon. VATS patients thus enjoy shorter recovery times, reduced post-operative pain, and lower complication rates as compared to patients that undergo comparable non-VATS surgeries.
VATS came into widespread use beginning in the early 1990s. Operations that traditionally were carried out with thoracotomy or sternotomy that today can be performed with VATS include: biopsy for diagnosis of pulmonary, pleural or mediastinal pathology; decortication for empyema; pleurodesis for recurrent pleural effusions or spontaneous pneumothorax; surgical stapler assisted wedge resection of lung masses; resection of mediastinal or pleural masses; thoracic sympathectomy for hyperhidrosis; operations for diaphragmatic hernias or paralysis; esophageal resection or resection of esophageal masses or diverticula; and VATS lobectomy/mediastinal lymphadenectomy for lung cancer.
Similarly to laparoscopy, VATS has enjoyed widespread use for technically straightforward operations such as pulmonary decortication, pleurodesis, and lung or pleural biopsies. More technically demanding operations such as esophageal operations, mediastinal mass resections, or pulmonary lobectomy for early stage lung cancer are at present performed via VATS primarily at selected centers. It is expected, however, that the prevalence of advanced VATS techniques will continue to increase in response to patient demand and increased surgeon familiarity with the techniques.
Conventional camera systems for VATS typically include a camera-linked 5 mm or 10 mm fiber-optic scope and thoracic or laparoscopic instruments. Scopes commonly feature a 30-degree angle of visualization. Unlike with laparoscopy, carbon dioxide insufflation is not generally required with VATS due to the inherent vault-like shape of the thoracic cavity. However, lung deflation on the side of the chest where VATS is being performed is required to support visualization and allow for instruments to pass into the thorax. Lung deflation is usually accomplished with a double-lumen endo-tracheal tube that allows for single lung ventilation or a bronchial blocker delivered via a standard single-lumen endotracheal tube.
These conventional VATS camera systems feature long, rigid camera rods that are passed between a patient's ribs. This design introduces a number of challenges to both the surgical team and the patient. First, it is often necessary to create one or more separate incisions to accommodate the camera, with the surgeon operating from a separate port. The incisions themselves cause some amount of postoperative pain to the patient. Even for uniportal approaches (wherein the scope is inserted through the same incision that the surgeon operates through), pain can be exacerbated by intracostal nerve damage caused by manipulation and re-insertion of the rigid scope against the patients' rib bones. This damage can cause post-operative neuralgia and even induce chronic pain in some patients.
From the surgical team's perspective, conventional VATS scopes must be held and manually manipulated during the procedure. Even with such manipulation, it is often difficult to visualize the relevant structures due to the camera form factor. A camera at the end of a rigid rod may be sufficient for laparoscopic procedures that only require navigation around a patient's soft tissues. However, such designs are deficient for thoracic surgeries that necessitate navigation around the patient's ribs.
Conventional VATS are operated by a dedicated camera operator or an existing member of the surgical team. Dedicated operators add additional expense to the procedure, take up valuable room in the operating room, and often introduce additional barriers to the operational field itself, particularly for uniportal approaches that require both the camera operator and surgeon to work through the same small incision. Use of existing members of the surgical team as camera operators distracts them from their other duties in the operating room, and any camera operator may fail to manipulate the camera in a way that the surgeon prefers. Indeed, some surgeons prefer to operate their own cameras with one hand while performing surgery with the other.
A state-of-the art surgical robot with a camera is the da Vinci® surgical system. This system includes a tubular camera that is mounted to a robotic arm. Such a camera is poorly suited for thoracic surgery because of the limited space between the ribs with the cameras tubular shape. Current laparoscopic and robotic instrumentation designed for abdominal surgery is based on a circular port system, even for newer uniportal platforms. This is because there is no specific limitation in any particular direction when inserting ports into the abdomen. The circular or tubular design allows for the most efficient space for instrument insertion. In contrast, the spaces between the ribs, the intercostal spaces, are limited and vary widely based on the patients' body habitus. The intercostal space may range from approximately 5 mm up to 20 mm in width. A circular or tubular port will be restricted by the width of the intercostal space while the length of the intercostal space could better accommodate ports with more oblong shape or systems that provide a flat interface as the instruments or cameras enter between the ribs. The da Vinci® surgical system is therefore most often employed for other surgeries, including surgeries of the abdomen and pelvis.

Multifunctional camera system for video assisted thoracic surgery

Board of Trustees of Southern Illinois University


A spring-loaded outboard side lock for restraining the movement of a cargo body. The outboard side lock (10) includes a base (20) secured to the outboard sides of a main cargo deck (12), the base having a guideway (38) in which a plunger (22) is slidably mounted. The plunger has formed in it a recess (44) and a pair of abutment walls (52) that extend generally perpendicular to the bottom of the plunger. An actuator (54) is disposed within the recess and is coupled to a lever (24) for reciprocal movement, and a pair of springs (50) extend between a pair of transverse spring abutting wings (64) of the actuator and the abutment walls of the plunger. Activation of the lever moves the actuator toward the cargo body (16) to be restrained, whereby the transverse spring abutting wings of the actuator act against the springs, which act against the abutment walls, to urge the plunger into engagement with the cargo body to restrain its movement and to maintain engagement in the event the cargo body attempts to move away from the outboard side lock. Deactivation of the lever causes the plunger to disengage the cargo body, thereby permitting its movement.

In most large airplanes, it is standard for floor beams to run in a lateral direction, except in the wing box section where the floor beams run in a forward and aft direction. As a result, the floor beams over the wing box flex (i.e., expand and contract laterally) with movement of the wings. While this flexing may occur at any stage of the airplane's flight, it is most pronounced as the wings bounce up and down during taxiing, especially at high gross weights. With airplanes that carry fuel in their wings, the wings have an even lower resting position and the resulting wing bounce exerts even greater flexing to the floor beams than is found in airplanes not carrying fuel in this manner.
In cargo airplanes, loaded containers and pallets normally sit two abreast across the width of the airplane, each container or pallet being secured to the main cargo deck on the inside by centerline restraints and on the outboard side by vertical restraints and side locks. Current side locks have a plunger that is extendable to engage a receptacle in the container or the top of the outboard lip of the pallet. As a result, the plunger acts as a vertical restraint for pallets and as both a vertical and horizontal restraint for containers.
End locks are always placed forward and aft of pallets to provide the required horizontal restraint, since the side locks provide none. End locks are also placed forward and aft of most containers to provide horizontal restraint in addition to that provided by the side locks. However, with containers of significant length (e.g.,20 and 40 feet), it is not possible to use end locks at all. Consequently, the sole horizontal restraint for these large containers is that provided by the side locks.
In order for the cargo containers and pallets to be loaded, the distance from the centerline restraints to the outboard vertical restraints and side locks must be slightly greater than the width of the container or pallet. If not, there would not be the clearance required to move the cargo into position. Additionally, it is quite common for containers and pallets to be slightly undersized because the manufacturers do not closely follow the dimensional specifications set for the containers and pallets.
Consequently, the combination of a slight amount of clearance, an undersized container or pallet, and the outboard movement of the side lock due to flexing of the beam upon which it is mounted may lead to the plunger being pulled out of engagement with the container or pallet. When this occurs with a large container not capable of being end locked, the container becomes unrestrained, which can lead to catastrophic events.
As a result, there has been a long-felt need for an outboard side lock for restraining large containers over the wing box section of cargo airplanes that maintains contact with the container even during periods of extreme floor beam flexing. This invention is directed to satisfying this need.


A system identifies a movement and generates prescriptive analytics of that movement. To identify a movement, a system accesses an image of an observation volume where users execute movements. The system identifies a location including an active region in the image. The active region includes a movement region and a surrounding region. The system identifies musculoskeletal points of a user in the location and determines when the user enters the active area. The system identifies a movement of a user in the active region based on the time evolution of key-points in the active region. The system determines descriptive analytics describing the movement. Based on the descriptive analytics, the system generates prescriptive analytics for the movement and provides the prescriptive analytics to the user. The prescriptive analytics may inform future and/or current movements of the user.

Various methods to identify movements of a user exist. A classic example is motion capture in modern cinema. In motion capture, a user wears small identifying objects at key-points about their body while they execute various movements in an active region. A camera system obtains images of the user and utilizes the captured key-points to generate various analytics for the movement. For example, motion capture systems have been applied to athletes during training sessions such that coaches can derive various heuristics describing their movements.
Movement identification becomes a complex problem when applied to multiple simultaneous users which perform dissimilar movements in different active regions. Unfortunately, related art systems have failed to solve this complex problem without the use of complex indicator systems. To illustrate, the related art system utilize numerous indicator devices attached to each user which may hamper their movements. Additionally, related art systems use visual indicators indicating the extent of an observation volume which limits freedom of movement for users. Related art systems do not address determining active regions and movements of users in those active regions without the use of physical and/or electronic indicators in the observation volume.
The figures depict various embodiments for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein.

Identifying movements and generating prescriptive analytics using movement intelligence


A method and apparatus for performing H-ARQ transmission is described herein. Bits received on a first transmission are stored and combined with the bits received on later transmissions thereby increasing the likelihood of a correct decoding on later transmissions. Additionally, a plurality of coding schemes (e.g., Convolutional Codes, Block Turbo Codes, Convolutional Turbo Codes, Low Density Party Check Codes, . . . , etc.) are utilized, with an information element being reserved to signal what form of H-ARQ is being utilized.

Digital data transmissions over wired and wireless links sometimes may be corrupted, for instance, by noise in the link or channel, by interference from other transmissions, or by other environmental factors. Even with clear communication channels, which lend themselves to high data rates, it may not be possible to appropriately decode the data stream with the requisite error rates. In order to solve this problem, many current communication systems employ an automatic repeat request (ARQ) scheme for retransmission. In such systems an opportunity exists for requesting that data be retransmitted upon detection of an error. In more complex systems a hybrid ARQ scheme is employed.
In systems employing a hybrid ARQ (H-ARQ) scheme, a receiver combines previously received erroneous transmissions of a packet of information with a newly received transmission in an effort to successfully ascertain the true contents of the packet. In other words, coded bits received on a first erroneous transmission are stored and combined with the coded bits received on later transmissions thereby increasing the likelihood of a correct decoding on later transmissions. Similarly the coded bits received on the second or later transmissions are stored for combining with subsequent received bits.
As one of ordinary skill in the art will recognize, the form of H-ARQ utilized by any communication system is directly dependent upon the type of coding mode utilized. For example, a system employing multiple types of forward error correction (FEC) modes, like Convolutional Codes (CC), Block Turbo Codes (BTC), Convolutional Turbo Codes (CTC) and Low Density Party Check Codes (LDPC), must identify which FEC mode is being utilized in conjunction with the H-ARQ. Moreover, many parameters like the information block size, resource allocation size and incremental redundancy version will be dependent on the FEC mode. With next-generation communication systems employing multiple coding modes, it is impossible to utilize a single H-ARQ signaling scheme and cover all available FEC modes. Therefore a need exists for a method and apparatus to a multi-mode hybrid ARQ within a communication system employing several coding modes.


A method for reducing the turn-back in response to an actual and a target speed in an optical storage device. The method includes the following steps: (a) determining whether the turn-back of the optical pickup head occurs; if the turn-back occurs, step (b) is executed and if the turn-back does not occur, a speed error is obtained according to the target speed and the actual speed; (b) determining whether the number of turn-back tracks is greater than a default value; if the number of turn-back tracks is not greater than the default value, the speed error is set to zero and if the number of turn-back tracks is greater than the default value, the speed error is obtained according to the target speed and an inversion of the actual speed and the actual track-seeking direction is inverted to correspond to the target track-seeking direction.

This application incorporates by reference Taiwanese application Serial No. 89101716, filed Feb. 1st, 2000.
1. Field of the Invention
The invention relates in general to a method for reducing the turn-back of the track-seeking control in an optical storage device and an apparatus thereof.
2. Description of the Related Art
FIG. 1 is a block diagram illustrating the structure of an optical storage device. The optical storage device indicated here includes at least a CD-ROM drive and a Digital Versatile Disk (DVD) drive.
Referring to FIG. 1, a spindle motor 100 is used to drive an optical disk 101 to the required rotation speed. A sled motor 102 is used to drive the sled 105 which is equipped with an optical pickup head 104 for rough tracking and seeking operations. The tracking operation is used to drive the optical pickup head 104 to a certain track on the optical disk 101 for reading data.
Fine-tuning operations include focusing and tracking operations. The focusing operation involves the objective lens 120 running in a vertical direction in order to accurately read data on the optical disk 101 whereas the tracking operation involves the objective lens 120 running in a horizontal direction to find the desired track.
When a laser is focused on the optical disk 101, the reflected light is received by the optical sensor on the optical pickup head 104. Optical pickup head 104 outputs the signals corresponding to data stored in the optical disk 101 as well as signals for various servo controls.
The signals outputted from the optical pickup head 104 are transformed by a preamplifier 106 into radio frequency (RF) signals and other signals for various servo controls such as tracking error (TE) signal, RFRP signal, and RFCT signal. These signals are then inputted to the control integrated circuit (control IC) for processing. Included in the control IC 108 are, for example, a digital signal processor (DSP) in addition to other analog or digital circuitry. The control IC 108 obtains an output data by performing the demodulation and error correction of the received RF signals and sends out the output data to the decoder 112 and then the host computer 114 for further processing. Meanwhile, the control IC 108 processes the servo signals with necessary compensations and outputs to power amplifiers 116 and 118 to drive the spindle motor 100, the sled motor 102, the focusing actuator and the tracking actuator.
The microprocessor 122 is responsible for the overall operation of the disk as well as the user interfaces such as controlling the opening of the disk tray.
Next, signals obtained by the optical pickup head 104 is inputted to the preamplifier 106 which outputs the RF signal, and other signals for various servo controls, for example, the TE signal, the RFRP signal, and the RFCT signal. Then, these signals are processed by the control IC 108 such as a digital signal processor, DSP, or other digital or analog circuits. The control IC 108 processes the RF signal with error correction and outputs data to the decoder 112. Then, the output of the decoder 112 is inputted to the main computer 114 for further processing. On the other hand, the control IC 108 outputs the servo signals to the power amplifiers 116 and 118 for driving the spindle motor 100, the sled motor 102, the focusing actuator and the tracking actuator of the objective lens 120 in the optical pickup head 104.
Moreover, the microprocessor 122 controls the whole process and the user interface of the optical storage device, for example, the opening the tray of the optical storage device.
Referring to FIG. 2, the flow chart of the track-seeking control is illustrated. Before the track-seeking control starts, in step 200, the target is set up. The target is a position of an optical disk for reading data. For a CD-ROM, the target is a data block number, and, for a DVD-ROM, the target is a data sector number.
In step 202, the current position is read. In step 204, whether the current position is the target is determined. If the current position is the target, the track-seeking control is ended. On the other hand, if the current position is not the target, in step 206, the direction and the number of tracks needed for the track-seeking control is calculated from the difference between the target and the current positions.
Next, step 208 is executed whereby the tracking operation ends and the track-seeking control starts. Then, in step 210, whether the number of traversed tracks is equal to the number of tracks needed for the track-seeking control is determined. If not, step 208 is repeated. If yes, in step 212, the track-seeking control is ended and the tracking operation is started and step 202 is repeated.
Generally, there is a phenomenon called eccentricity for the optical disk 101. The eccentricity is formed due to the fact that the center of the optical disk 101""s circular hole is not located exactly in the center. Moreover, sometimes, when the optical disk 101 is spinning, there are vertical and horizontal vibrations. As a result, when the optical pickup head 104 is in seeking control, the turn-back occurs under some circumstances. For example, because of the serious eccentricity of optical disk 101 or noises when in low-speed track-seeking control or actuator""s inertia when the sled motor is speeding up or slowing down, the turn-back of the optical pickup head occurs.
FIG. 3 is a block diagram illustrating the track-seeking control of the optical storage device. The RF signals reflected from the optical disk 101 are received by an optical pickup head 300, and amplified by the preamplifier 302. After the procession of the track-seeking processor 304 and the frequency compensation of the compensators 306 and 308, the RF signals are inputted to power amplifiers 310 and 312 for fine tuning of the objective lens actuator 314 and rough tuning of the sled motor 316, respectively. Then, the whole process is repeated until the target track is found, that is, the purpose of the track-seeking control is achieved.
Here, the track-seeking processor 304 and compensators 306 and 308 are in the control IC 108 shown in FIG. 1. The track-seeking processor 304 is used to reduce the turn-back of the track-seeking control of the optical storage device according to the invention.
Referring to FIG. 4, a diagram of the target speed and the actual speed of the track-seeking control is illustrated. In FIG. 4, the unbroken line 40 represents the target speed and the dotted line 42 represented actual speed. Considering the target speed first, it is assumed that the pickup head is to jump over 200 tracks. Speed of track-seeking control is kept at 20 kHz at the beginning. Then, when residual track number is 100, speed of track-seeking control slows down. The reasons that the target speed is set in this way are illustrated below. Because there are many tracks for seeking at the beginning, the target speed can be set in a higher speed. Then, when the target track is approached, the speed of track-seeking needs to slow down for preventing that the target track cannot be locked correctly because of inertia of the pickup head.
The actual speed of the pickup head starts from zero and responsive to the target speed until the target track is approached.
The difference between the target speed and the actual speed is called speed error. The speed error feeds back to the track-seeking processor 304 for controlling the spinning speed of the optical disk 101. When the actual speed is smaller than the target speed, the speed error is positive. Then, when the speed error is fed back to the compensator, the actual speed is increased. On the other hand, when the actual speed is greater than the target speed, the speed error is negative. Then, when the speed error is fed back to the compensator, the actual speed is decreased.
Referring to FIG. 5 and FIG. 6, FIG. 5 is a block diagram illustrating the track-seeking processor 304 shown in FIG. 3 and FIG. 6 is a timing diagram of some relative signals. A radio frequency zero crossing (RFZC) signal and a tracking error zero crossing signal (TEZC) signal, which are outputted from the preamplifier 302, are inputted to the track-seeking processor 304 for further processing.
The RFZC signal is derived from a RFRP signal and a slice level of the RFRP signal. For example, the zero amplitude level of the RFRP signal is taken as the slice level. When the RFRP signal is greater than the slice level, the RFZC signal is in the high level. On the other hand, when value of the RFRP signal is smaller than the slice level, the RFZC signal is in the low level.
The RFRP signal is derived from a RF signal. When the pickup head is focused on a track, the RF signal is the greatest. When the pickup head is focused between two tracks, the RF signal is the lowest. The RFRP signal is derived by difference between the lower envelope of the RF signal and the upper envelope of the RF signal, or by low-pass filtering of the RF signal.
Similarly, the TEZC signal is derived from a TE signal and a slice level of the TE signal. For example, the zero amplitude level of the TE signal is taken as the slice level. When the TE signal is greater than the slice level, the TEZC signal is in the high level. On the other hand, when the TE signal is smaller than the slice level, the TEZC signal is in the low level.
The TE signal is used as an indication for track-locking or not. For example, on time T2, the TE signal is zero, which means that the objective lens 120 in FIG. 1 is focused on the track. However, when the objective lens 120 is focused between two tracks, the TE signal would be zero, too, such as on time T4. When the objective lens 120 is focused on the edge of a track, the absolute value of TE signal is the greatest, such as on time T1 and T3.
Therefore, one cycle of the TE or the RF signals represents that the optical pickup head is jumped through one track. In the same manner, one cycle of the RFZC signal or the TEZC signal means that the optical pickup head is jumped through one track. As a result, the actual speed of the optical pickup head can be derived from the RFZC signal and the TEZC signal, which is the function of the actual speed detector 500.
Moreover, the relation between the RFZC and TEZC signal is illustrated below. When the optical pickup head moves inward relative to the optical disk, such as after time T5, the TEZC signal leads before the RFZC signal by 90 degrees. On the other hand, when the optical pickup head moves outward relative to the optical disk, the RFZC signal would lead before the TEZC signal by 90 degrees, such as before time T5. Due to this characteristic, by comparing the phase difference between these two signals, the track-seeking direction of the optical pickup head can be found out, which is the function of the direction detector 502.
In the timing diagram illustrating the track-seeking direction shown in FIG. 6, the high level means that the track-seeking direction is outward while the low level represents that the track-seeking direction is inward. Moreover, the track-seeking direction changes on time T6 rather than time T5 because the track-seeking direction detected by the direction detector 502 is derived by detecting the phase change between the RFZC signal and the TEZC signal. This is why track-seeking direction is changed on time T6.
The track number counter 504 derives the number of tracks jumped by the optical pickup head from the TEZC and RFZC signal. Then, the number of tracks derived is inputted into the target speed generator 506 to obtain the target speed needed. The target speed generator 506 derives the target speed from the target speed curve shown in FIG. 4 by referencing the number of tracks obtained by the track number counter 504.
The speed error generator 508 receives data from the actual speed detector 500, direction detector 502, and target speed generator 506 and generates a speed error signal, which is inputted into the compensator 306, for example.
As mentioned above, when the optical pickup head is in the track-seeking control, the turn-back occurs under some certain conditions. When the turn-back occurs, it means that the track-seeking direction is wrong. If this turn-back cannot be reduced in time, it results in inaccurate number of tracks sought, increase of data access time, etc.
Moreover, if the track-seeking method does not consider the turn-back, it can result in error in the track-seeking control. Generally speaking, when turn-back is not considered, the speed error is obtained by subtracting the actual speed from the target speed. Once the turn-back occurs, if the speed error is positively fed back to the compensator, the divergence of the track-seeking control occurs.
For example, if the desired track-seeking direction is outward, the target speed is 5 kHz, actual speed is 6 kHz, and the actual track-seeking direction is outward, the speed error is 5 kHzxe2x88x926 kHz=xe2x88x921 kHz. As a result, the compensator drives the actuator of the optical pickup head to move inward, which results in a reduction of the speed of the optical pickup head to approach the target speed.
On the other hand, if the turn-back occurs, it means that the desired track-seeking direction is outward but the actual track-seeking direction is inward. For example, when the actual speed is 6 kHz, the speed error is still xe2x88x921 kHz. Therefore, the compensator drives the actuator of the optical pickup head inward to reduce the speed of the optical pickup head. However, since the turn-back occurs, the actual track-seeking direction is inward rather than outward. Thus, the inward force generated by the actuator of the optical pickup head makes the optical pickup head far away from the target track, which results in the divergence of the track-seeking control.
Conventionally, when the turn-back is detected, the track-seeking control is forced to cease and begin again. However, this conventional method has the following disadvantages. First, when the track-seeking control is forced to cease, the tracking operation is forced to complete and the current position is informed to obtain the position and the direction needed for the new track-seeking control, which results in an increase of overall access time. Second, due to the inertia of the optical pickup head, sudden cease of the track-seeking control results in the instability of the whole system.
It is therefore an object of the invention to provide a method for reducing the turn-back of the track-seeking control in an optical storage device. When the turn-back occurs, the direction of the optical pickup head can be effectively corrected to the right direction to proceed with the track-seeking control rather than forcing the track-seeking control to cease and start again in the conventional method. Thus, the stability of the system is increased and the track-seeking time is reduced. Also, the temporary or the erroneously determined turn-back causes by noises can be prevented.
The invention achieves the above-identified objects by providing a method for controlling the turn-back in response to an actual speed and a target speed in an optical storage device. The method includes the following steps: (a) determining whether the turn-back of the optical pickup head occurs; if the turn-back occurs, step (b) is executed and if the turn-back does not occur, a speed error is obtained according to the target speed and the actual speed; (b) determining whether the number of turn-back tracks is greater than a default value; if the number of turn-back tracks is not greater than the default value, the speed error is set to zero and if the number of turn-back tracks is greater than the default value, the speed error is obtained according to the target speed and an inversion of the actual speed.
The invention achieves the above-identified objects by providing a track-seeking processor for reducing the turn-back in an optical storage device having a pickup head in response to a TEZC signal and a RFZC signal. The track-seeking processor includes an actual speed detector, a direction detector, a track number counter, a target speed generator, and a speed error generator. The actual speed detector receives the RFZC signal and the TEZC signal to obtain an actual speed of the optical pickup head of the optical storage device. The direction detector receives the RFZC and TEZC signals to obtain the track-seeking direction of the optical pickup head by a phase difference between the RFZC and TEZC signals. The track number counter receives the TEZC signal or the RFZC signal to obtain the number of tracks jumped by the optical pickup head. The target speed generator is connected to the track number counter and receives the number of tracks generated by the track number counter to obtain a target speed of the optical pickup head. The speed error generator is connected to the actual speed detector, direction detector, track number counter, and target speed generator for generating a speed error. When the turn-back does not occur, the speed error is set according to the target speed and the actual speed. When the turn-back occurs, if the number of turn-back tracks is not greater than a default value, the speed error is set to zero; if the number of turn-back tracks is greater than a default value, the speed error is set according to the target speed and inversion of the actual speed, and the turn-back is controlled by the speed error.

Method for reducing the turn-back of the track-seeking control in an optical storage device and apparatus thereof