A functionally gradient circuit board is constituted by a mixture of a metal and an insulating ceramic composition, the abundance ratio of the metal component to the component of the insulating ceramic composition being changed in the direction of thickness of the board.

1. Field of the Invention
The present invention relates generally to a circuit board such as an IC board, and more particularly, to a circuit board constructed using a functionally gradient material.
2. Description of the Prior Art
Conventionally, circuit boards made of various materials have been used so as to construct an electronic circuit. Of the circuit boards, a high power IC board and a power module board are constructed using a material superior in thermal conductivity because a circuit element carried thereon generates a great amount of heat.
One example of the circuit boards constructed using, for example, a metal material is shown in FIG. 6. A metal composite board 1 shown in FIG. 6 has a structure in which a metal plate 1a made of aluminum or the like, a synthetic resin layer 1b made of epoxy resin or the like, and a copper foil 1c are laminated. In the metal composite board 1, heat generated in a circuit element carried thereon is effectively radiated utilizing high thermal conductivity of the metal plate 1a. In addition, the metal composite board 1 is superior in mechanical strength to a ceramic board because it uses the metal plate 1a as a base material.
However, the metal composite board 1 has the disadvantage in that it is not sufficiently high in heat resistance so that it is liable to be softened at a temperature of a maximum of 300.degree. C. because the synthetic resin layer 1b is provided so as to achieve electrical insulation.
Moreover, since the metal composite board 1 has the above described laminated structure, it also has the disadvantage in that thermal stress is concentrated on the boundary between the layers due to the difference in coefficients of thermal expansion of materials of the respective layers, so that stripping or the like is liable to occur in the boundary between the layers due to heat shock.


Method, systems, and devices are described for determining traffic volume of one or more path segments. A computing device may receive probe data associated with a road segment from one or more sources. The computing device selects either a free flow algorithm or a congestion algorithm for the probe data, and calculates an estimated probe quantity from historical data using either the free flow algorithm or the congestion algorithm. A traffic volume may be estimated from the estimate probe quantity.

Traffic reporting is the study of movement of vehicles on the roads. Analytical techniques may manage and track traffic information and derive travel times, guide driving behavior and optimize road infrastructure for cities. Traffic Message Channel (TMC) and other traffic services deliver traffic information to customers. Traffic incidents and traffic flow are reported through broadcasts. Traffic delays may be caused by one or more of congestion, construction, accidents, special events (e.g., concerts, sporting events, festivals), weather conditions (e.g., rain, snow, tornado), and so on. Traffic services typically provide a speed or a range of speeds (e.g., low, medium, high) for a particular road. Another characteristic, traffic volume measures the total throughput of traffic for a particular road over a given span of time. Traffic volume could be measured using sensors that detect every car passing a particular point on the road. The sensors could be any combination of inductive loops embedded in the roadway, radar, or cameras. These sensors can be expensive to install and maintain, and their availability varies from location to location.


A cable raceway support device for an aircraft, formed from an electrically conductive material, comprising a pedestal having a fastening plane for the fastening of the device onto a primary structure and also having, on a support face which is an opposite face to the fastening plane, at least one pair of jaws having at least one electrical contact enabling a sliding electrical contact to be formed and the support face has a contact that projects, and also has a jaw overhanging the support face, the jaw forming with part of the pedestal the pair of jaws forming a stirrup-shaped clamp comprising a base and two branches, one branch of the clamp merging with the pedestal, and the other branch of the clamp corresponding to the jaw and bearing a second contact facing the first contact.

In an aircraft, it is known to use a cable raceway comprising a structure within which come to be housed the supported cables and further comprising a cover closing and retaining all the cables housed in the structure.
The structure is for example a structure of profiled cross-section comprising a planar base on one side of which extend longitudinal walls perpendicular to the base and parallel to each other. Together with the base, two neighboring longitudinal walls thus form a channel configured to serve as a housing for cables.
The known cable raceway structures are generally of metal. Such a cable raceway provides various functions. First of all it supports and mechanically protects cables and/or cable harnesses. Thanks to the presence of several channels, it also provides physical segregation of various cables. The cable raceway also provides thermal drainage by conduction and protection of the cables against electromagnetic interference to which they may be subjected. This last function in particular makes it possible to avoid additional shielding for the cables.
Most aircraft comprise a metallic structure which provides the return for the current transported by cables housed in the cable raceways. The aircraft of modern design increasingly use structural parts of composite material Return of the current is then no longer provided by the structure. A return for current should therefore be provided. Such a return is then provided by a distinct electrical link produced using wires or a bar of aluminum to provide for the return of the transported current. The drawback of this solution is that it increases the on-board mass of the aircraft.
Patent application FR-2 905 037 provides a cable raceway that makes it possible to keep the advantages of the cable raceways of the prior art without penalizing the mass of the aircraft. The cable raceway provided in that prior art document comprises a metallic structure of profiled cross-section having one or more housings for receiving cables. A layer of insulating material then covers the face of the cable raceway that is configured to bear on a carrying wall of the aircraft. The cable raceway described in that prior patent application is then used to provide the return of the current transported in the cables.

Cable raceway support device for an aircraft, in particular an aircraft with a structure at least partly formed from a composite material


An image forming apparatus includes: an apparatus body, a paper feed cassette, a feed section, an operation control section, a paper passage detection sensor, a cassette attachment-detachment detection sensor, a paper presence-absence detection sensor, a sensor failure determination section, and an alarm control section. The paper passage detection sensor detects whether or not paper has passed through a position. The cassette attachment-detachment detection sensor detects attachment or detachment of the paper feed cassette. The paper presence-absence detection sensor detects paper absence when the paper feed cassette is withdrawn from the apparatus body. The sensor failure determination section determines that the paper presence-absence detection sensor is in failure. The alarm control section, when passage of the paper is not detected before passage of a predefined time period, alarms that the feeding of the paper has failed.

This disclosure relates to an image forming apparatus, and more specifically to a technology of detecting failure of a sensor detecting paper presence or absence in a paper feed cassette.
Typically, an image forming apparatus of an electrophotographic type such as a copier, a printer, a facsimile device, or a multifunction peripheral includes a paper feed cassette which is attachable to and detachable from an apparatus body and which is capable of storing a large volume of paper. At time of printing execution, the image forming apparatus feeds, individually page by page, the paper from the paper feed cassette fitted to the apparatus body to an image formation section in the apparatus body.
Without any paper in the paper feed cassette, the image forming apparatus cannot feed paper to the image formation section, and thus cannot execute print processing. Thus, known as the image forming apparatus is the one which includes a paper presence-absence detection sensor for detecting paper presence or absence in the paper feed cassette, and which stops an operation of paper feed from the paper feed cassette in a case where the paper presence-absence detection sensor detects that paper is absent in the paper feed cassette.


A motor drive apparatus of an electric forklift includes first and second torque command value generation units that individually generate a torque command value indicating torque of a corresponding traveling motor in response to a gap between a speed command value and a speed detection value; and first and second slip detectors that individually generate a slip ratio estimation value showing a slip state of a corresponding drive wheel based on the speed detection value and the torque command value. The slip detectors individually have a first arithmetic unit which generates an inertial force estimation value proportional to a differential value of the speed detection value of the corresponding traveling motor and a second arithmetic unit which generates the slip ratio estimation value in response to a relationship between the corresponding inertial force estimation value and the torque command value of the corresponding traveling motor.

1. Technical Field
The present invention relates to a motor drive apparatus for an electric forklift.
2. Description of the Related Art
As an industrial vehicle, there is an electric forklift having a battery as a source of power. The electric forklift (hereinafter, may simply be referred to as forklift) includes a traveling motor transmitting the power to front wheels which are traveling wheels (drive wheels), a hydraulic actuator motor (steering motor) transmitting the power to a hydraulic pump that controls a turning angle (steering angle) of rear wheels which are turning wheels, a hydraulic actuator motor (cargo-handling motor) transmitting the power to a hydraulic pump that controls a lifting body, and electric power conversion devices which respectively drive the traveling motor, the steering motor and the cargo-handling motor.

Motor drive apparatus for electric forklift and electric forklift adopting the same


A liquid ring pump, includes a stationary housing having an interior space for accommodating at least one rotor mounted on a rotor shaft for rotation in the housing. The rotor shaft is supported by a bearing in the interior space, and the rotor is operated by a drive which acts on the outer perimeter of the rotor.

The present invention relates especially but not exclusively to a liquid ring pump.
German Pat. No. DE 27 31 451 describes a liquid ring pump or compressor having a rotor floatingly mounted to the extended shaft end of the drive motor. The motor casing is so configured that operating liquid of the compressor or pump is able to circulate therein and cool the motor housing. Apart from the fact that the motor casing must be designed in a particular way, it is also necessary to provide reinforced motor shafts and shaft bearings as well as complex seals between the pump or compressor, on the one hand, and the drive motor, on the other hand, whereby the space for the seals is relatively small and inaccessible during operation.
German Pat. No. DE 26 45 305 describes a liquid ring pump and compressor having a rotor accommodated in a hermetically sealed casing, with the seals configured in the form of glands or mechanical seals. Disposed about the housing are coils to form a stator winding. As the coils are excited, a field is induced in the ferromagnetic liquid contained within the housing, thereby forming a peripheral liquid ring adhering to the interior surface of the casing. Interaction between the ring and the rotor vanes causes the rotor to turn to implement a pumping action. The drive of the rotor is thus based on a magnetic engagement of the rotor with the field. As a consequence, the use of nonmagnetic materials such as stainless steels, high alloy nickel or plastics for the rotor is precluded. However, these types of materials are in particular suitable for rotors in liquid ring pumps handling toxic and/or aggressive transport fluids. In addition, the transmission of driving forces through induction of a field has a relatively poor efficiency.
To solve these problems, German Pat. No. DE 29 12 938 discloses a liquid ring pump having a cylindrical pump housing with a rotor mounted eccentrically in the housing. An electric motor drives the pump via a canned magnetic coupling which is hermetically sealed from the pump portion by an enclosure, thereby attempting to combine better driving conditions with a hermetic seal of the pump housing. Apart from the fact that canned magnetic couplings are only suitable for pump outputs of up to about 50 KW, this conventional liquid ring pump requires numerous bearings. The interior of the pump requires two slide bearings for supporting the pump shaft on which an inner magnet carrier of the magnetic coupling is mounted. Further, two roller bearings are provided to hold an outer magnet carrier of the magnetic coupling, and two regular bearings are provided for the separate electric motor. Thus, a total of six bearings is required, resulting in a complex configuration that leads further to a relatively great structural length of the overall apparatus comprised of pump, canned magnetic coupling and electric motor. When damage occurs, in particular of the enclosure, the magnetic coupling and the supporting bearing react relatively sensitively. Thus, it is not easy to provide measures which prevent or at least substantially reduce the risk of escape of transport fluid or operating fluid of the pump, when the enclosure is damaged. In particular, when toxic and/or aggressive or expensive transport fluids are involved, an escape of such fluids is detrimental.
It would therefore be desirable and advantageous to provide an improved liquid ring pump which obviates prior art shortcomings and which is compact and simple in structure while yet reliable in operation for basically any type of operating fluid.
According to one aspect of the present invention, a liquid ring pump includes a stationary housing defining an interior space; at least one rotor mounted in the interior space on a rotor shaft for rotation in the housing; a bearing for supporting the rotor shaft in the interior space; and a drive, acting on the outer perimeter of the rotor, for driving the rotor.
The housing of the liquid ring pump may either be configured with a single interior space or split horizontally to divide the interior in several spaces, typically two spaces. This simplifies the fabrication of the housing. The rotor is suitably provided with a partition wall to separate the interior spaces.
According to another feature of the present invention, the bearings of the rotor shaft may be configured as slide bearings which are lubricated and cooled by the operating fluid. The rotor and the rotor shaft can suitably be made of a same material, for example in the form of a single-piece casting. This single-piece configuration is equally applicable for all known construction principles such as conical configuration of liquid ring pumps. There are no problems relating to gap seals between individual stages of a multi-stage liquid ring pump as the partition wall is immersed over the entire circumference in the liquid ring.
According to another feature of the present invention, the outer perimeter of the rotor may be configured as a gear wheel which projects into a bay of the housing and cooperates with a force-transmitting member of the drive in the form of a pinion which is accommodated in the bay and transmits the torque from the electric motor to the gear. The pinion is hereby lubricated by the operating fluid and has a pinion shaft which is suitably supported by slide bearings. The bay requires only one bore for passage of the pinion shaft, whereby the bore can easily be sealed by a gland or mechanical seal. Suitably, the electric motor of the drive is placed externally and has a driveshaft which is axially offset to the rotor shaft.
A liquid ring pump according to the present invention exhibits a superior efficiency compared to prior art pumps and requires a smaller torque of the drive. The useful portion of the working chamber can now be made of greater size than in conventional liquid ring pumps while maintaining same outer dimensions. Further, the rotor shaft may have a smaller diameter compared to conventional liquid ring pumps as the required drive torque is not transmitted via the rotor shaft. As a consequence of the conjointly rotating partition wall of the rotor, less frictional losses are encountered. Compared to conventional liquid ring pumps, a liquid ring pump according to the present invention requires less space and a reduced number of components. There is no need for a separate lubrication so that the liquid ring pump according to the present invention runs completely free from grease. Thus, also two-stage or multi-stage configurations as vacuum pumps and compressors are possible as differently split axial rotor halves may have varying diameters. Except for the feedthrough of the pinion shaft to the drive, the liquid ring pump according to the invention is completely hermetically sealed and only a single area (feedthrough in the bay) needs to be sealed.
According to another feature of the present invention, the rotor is driven by a device which influences the rotation speed of the liquid ring pump, with the electric motor driving the rotor via a converter or a gear mechanism. The liquid ring pump can then be utilized for a wide range of industrial processes which demand different rotation speeds, i.e. different compression conditions.
According to another feature of the present invention, an infinitely variable control of the rotation speed of a liquid ring pump according to the invention can be implemented by configuring the outer perimeter of the partition wall of the rotor in the form of a water turbine and thus to drive the rotor by a jet of a fluid such as gas or liquid, e.g. water. In this way, the rotation speed can be controlled by the applied fluid pressure or fluid amount. Configuration of such a hydrodynamic drive eliminates the need for a drive motor, thereby further reducing the dimensions of the overall liquid ring pump. Fluid pressure and fluid amount can be generated by a centrifugal pump, whereby the fluid is conducted in a closed loop or supplied from a cooling water mains if water is used as fluid. The amount of cooling water is hereby sufficient to avoid a recooling. The reservoir, typically designed as separator may, however, contain a cooling coil for recooling of the operating water. Thus, the driving water for the rotor can be used at the same time as operating water of the liquid ring pump.


A photosensitive resin composition is disclosed.. The photosensitive resin composition is characterized by containing (a) a reaction product of a polymer having a specific segment with (3,4-epoxycylohexyl)-methyl methacrylate, (b) a polymerization initiator allowing the initiation of the polymerization of said reaction product when irradiated with an actinic radiation, and (c) a solvent. Preferably, the composition further contains (d) a thermal crosslinker, a compound having a polymerizable unsaturated bond and/or a pigment in addition to the above ingredients.. According to the present invention, there is provided the photosensitive resin composition which has such excellent characteristics that it has high sensitivity, it does not require a heat treatment between exposure-development steps, it causes little change of sensitivity and pattern shape with time from the exposure to the development, it has high heat resistance, it permits the use of an aqueous system in the development step and it has good storage stability.

A color filter used in a liquid crystal display, an imaging device or the like element generally has a construction in which pixels in a mosaic or stripe form are arranged on a transparent substrate such as a glass and has been hitherto prepared by a dyeing method (T. Uchida et al, Record of International Display Res. Conf. (1982), 166, IEEE Trans. ED-30 (1983) 503), an electrodeposition method (M. Suginoya et al, Proc. Japan Display '83 (1983 206) or a printing method (Tsuda et al, Proceedings of 13th Liquid Crystal Forum (1987) 22).
According to the dyeing method, a perchromate or a water soluble azide is added to a water soluble polymer such as gelatin, casein or polyacrylamide to impart photosensitivity thereto. After exposure, a development step is performed to obtain a relief pattern which in turn is colored to obtain a colored image. By repeating the coloring step for red, blue and green colors to obtain a color filter. To prevent color mixing, a coloration preventing treatment with tannic acid is performed between the respective coloring steps or an intermediate layer of an acrylic resin is formed. Thus, the dyeing method includes complicated steps, so that it is difficult to control the color tone. Further, the dyeing method has drawbacks that the water soluble polymer which is a dyeing medium has poor heat resistance and the color has poor heat resistance and poor weatherability.
To solve the above defects, studies have been made on the electrodeposition method, printing method and pigment dispersing method. With the electrodeposition method, however, the colored film is so thick that there are caused problems such as a large voltage drop and a limitation in pattern arrangement. The printing method has drawbacks because of poor dimensional accuracy and poor surface smoothness.
To solve the drawbacks of the conventional methods, there is proposed a pigment dispersing method. In this method, a pigment is dispersed in a photosensitive resin and the dispersion is applied onto a substrate. After drying, exposure and development are carried out to obtain a colored image. Thus, this method has a merit that it enables to obtain color filters by a simpler process in comparison with the dyeing method. A variety of photosensitive resins have been proposed for use in the pigment dispersing method, such as photosensitive polyimide resins disclosed in JP-A-60-237403, photosensitive resins composed of an acrylic polymer and an azide compound and disclosed in JP-A-1-200353, 4-7373 and 4-91173, photosensitive resins composed of an acrylate monomer, an organic polymer binder and a photopolymerization initiator and disclosed in JP-A-1-152449, and a chemically amplified-type photosensitive resins composed of a phenolic resin, a crosslinking agent having an N-methylol structure and an agent capable of generating an acid upon irradiation with a light and disclosed in JP-A-4-163552.
While a high heat resistance is obtainable when a photosensitive polyimide is used as the photosensitive resin for the pigment dispersing method, there are drawbacks because of low sensitivity and of necessity to use an organic solvent in the development step. With a conventional system in which an azide compound is used as the photosensitive agent, there involve problems because of low sensitivity, poor heat resistance and susceptibility to oxygen during the exposing step. A system in which radical polymerization of an acrylate monomer is utilized poses a problem that the exposure step is affected by oxygen, so that the sensitivity is reduced considerably, though the sensitivity is high. To avoid the influence of oxygen, therefore, it is necessary to form an oxygen barrier film or to perform the exposure in an inert atmosphere. But this requires a complicated process and an expensive apparatus. The chemically amplified-type photosensitive resin for forming a image by a catalytic reaction by an acid generated upon exposure can give high sensitivity and is not adversely affected by oxygen during exposure. However, there involves a problem because it is necessary to introduce a heating step between the exposure and development steps and because the sensitivity and the pattern shape are affected by a period of time from the exposure to the development, so that it is difficult to control the process. Further, the conventional photosensitive resin composition has drawbacks that the stability during storage is not good.
On the other hand, the conventional pigment-free photosensitive resin composition has the same drawbacks as those in the above-mentioned, photosensitive resin composition used for the preparation of a color filter by using the pigment dispersion method. In the conventional pigment-free photosensitive resin composition, sufficient consideration has not been taken for the chemical resistance, heat resistance and transparency of a cured body obtained through an exposure step. Thus, when the conventional pigment-free photosensitive resin composition is used as a protective material for a coloring material layer, there are caused problems of poor heat resistance and poor chemical resistance, so that a considerable change of color occurs by heating and peeling occurs upon contact with chemicals. Under the existing circumstances, further improvement is desired.
It is, therefore, an object of the present invention to provide a photosensitive resin composition which has such excellent characteristics that it has high sensitivity, it does not require a heat treatment between exposure-development steps, it causes little change of sensitivity and pattern shape with time from the exposure to the development, it has high heat resistance, it permits the use of an aqueous system in the development step and it has good storage stability.
It is another object of the present invention to provide a pigment-free, photosensitive resin composition which has good heat resistance and good chemical resistance and which has a long shelf life.

Photosensitive resin composition for color filter production


A system, apparatus and a method for routing data over fewer switches and interconnections among reconfigurable logic elements, and for adapting routing resources to dynamically perform complex bit-level permutations, such as shifting and bit reversal operations. In one embodiment, an exemplary silo routing circuit is formed upon a semiconductor substrate and routes data among a number of reconfigurable computational elements. The silo routing circuit comprises a plurality of input terminals and a plurality of output terminals. Further, the silo routing circuit includes a multi-stage interconnection network (“MIN”) of switches configurable to form data paths from any input terminal to any output terminal.

As individual reconfigurable computational elements are adapted to perform more complex logic, arithmetic, and other processor-oriented functions, at least two vital structural components have emerged as impediments to efficient use of computational resources and to enhanced performance of reconfigurable processors. These two structural components are: (1) the programmable routing resources disposed within reconfigurable logic arrays, and (2) the bit permutation resources that are programmatically formed from reconfigurable computational elements.
As to the latter, specialized permutations circuits functions, such as shifting circuits, have been traditionally formed by programming reconfigurable computational elements to perform such functions. In conventional designs, a significant amount of computational resources are dedicated to support these shifter circuits and bit-manipulative circuits, which consume a relatively large amount of circuit area. Regarding the former, programmable routing resources (or routing networks) are crucial to connect an output of any one reconfigurable element to an input of any other reconfigurable element. To do so, reconfigurable computational elements as well as switches generally require configuration data to program their respective functionalities, which includes routing data. But as those functionalities become increasingly complex, the number of interconnections also increases, which thereby further burdens the routing resources. As a result, the increased number of interconnections in routing resources causes circuit area and timing delays to increase correspondingly.
FIG. 1 illustrates a conventional routing network typically formed within a reconfigurable logic array 100. Reconfigurable logic array 100 includes a number of Arithmetic Logic Elements ("ALEs") 101, 105, 106, 107 and 109 as reconfigurable computational elements for performing logic and arithmetic functions and requires a number of routing resources. First, a typical ALE 101 requires interconnections for receiving configuration data bits to implement logic functions and also requires interconnections between one to two logic outputs and three or more logic inputs to a routing network. Horizontal routing blocks 102 and vertical routing blocks 103 represent the routing network and each typically consist of a large number of switches for routing data among ALEs 101. Also, a large number of interconnections reside in routing blocks 102, 103 to support transport of configuration data bits to control the data path routings. For example, switches and interconnects at cross-bar routing block 108 must be sufficient to configure the routing of the output of ALE 105 to the input of ALE 109 by first routing data over one of horizontal routing blocks 102 and then routing data over one of vertical routing blocks 103.
FIG. 2A depicts a switch circuit 300 commonly used to facilitate data path routing in routing blocks 102, 103 of FIG. 1. Switch circuit 300 is a 16 input-to-1 output routing block that selects any one input 302 (e.g., any input P.0 to input P.15) and then routes data from a selected input 302 via an enabled cross-point gate 303 to output ("Y") 301. In operation, at most one static configuration signal 305 (i.e., any signal from "cf0" to "cf15") controls the activation of a specific cross-point gate 303. Static configuration signal 305 is a "static" signal. That is, it is generated by a specific configuration register, the contents of which are loaded when reconfigurable logic array 100 is initialized. Thereafter, the state of the static signals remains unchanged. FIG. 2B illustrates a typical implementation of cross-point gate 303 of FIG. 2A including an inverter 292 and a complementary metal-oxide semiconductor ("CMOS") transmission gate 294 to operate as a three-state switch.
FIG. 3 depicts a cross-bar routing block 108 for routing data via switch circuits 300 between the outputs and the inputs of the reconfigurable computational elements. In particular, FIG. 3 shows a specific data path for routing data from ALE (1) 106 to ALE (2) 107 as determined by the configuration bits routed into cross-bar routing block 108. Each of sixteen outputs from "O/P 0" to "O/P 16" of ALE (1) 106 is connected to a separate vertical switch in vertical routing blocks 103. Each of sixteen inputs from "I/P 0" to "I/P 16" of ALE (2) 107 is connected to a separate horizontal switch in horizontal routing blocks 102. As shown, output O/P 0 is connected to vertical switch ("SW-1V") 320a, which is a separate switch than switch ("SW-16V") 320b. Also, input I/P 16 is connected to horizontal switch ("SW-16H") 322b, which is separate from switch ("SW-1H") 322a for input I/P 0. Although omitted for purposes of discussion, other inputs and outputs each require a similar number of separate horizontal and vertical switches. Therefore, cross-bar routing block 108 does not use fifteen inputs of each switch and corresponding interconnections at any one time, which decreases the efficacy of cross-bar routing block 108 to maximize the use of its circuitry. Moreover, the relatively large number of switch circuits 300 consume circuit area that otherwise could be used for other purposes.
As an example, consider that cross-bar routing blocks 108 are used to route data in reconfigurable logic array 100 of N rows by N columns of reconfigurable computational elements, where "N" is 64. Further consider a simple case where there are only two inputs per reconfigurable computational element. As such, there would be a total of N2 or 4,096 reconfigurable computational elements requiring a total of 8,192 cross-bar routing blocks 108. As the combination of cross-bar routing blocks 108 would then yield 4,096 inputs, then a total of 33,554,432 switch circuits 300 would be needed (as well as an equivalent same number of configuration registers and corresponding bit paths).
A common approach to reduce routing resources requirements for a reconfigurable logic array includes adding one or more stages to form a multi-stage routing network, but retaining the use of cross-bar routing block 108. In this approach, either a set of horizontal routing blocks are configured to drive a set of vertical routing blocks, or vice versa. Or, these two approaches can be mixed as demonstrated in U.S. Pat. No. 6,633,181 B1, entitled "Multi-Scale Programmable Array," which is commonly owned by the owner of this application and is incorporated by reference in its entirety for all purposes. For example, for each row and column, there is a first stage of K switches with N inputs per switch and then a second stage of switches for each of the inputs with K inputs per switch. To compare the reduction of switches and interconnections in view of the previous example, consider K=64, such that there will 64 first stage routing circuits per row and 2*N second stage routing circuits per column, thus the total number of switches required for horizontal routing is 64*64*64=262,144, and the number of switches for vertical routing is 2*64*64*64=524,288. The total number of switches for this approach is 786,432. Although this approach reduces circuit area, there might be an increase in complexity in the placement of functions as well as a possible increase in delay time between the source and the destination for each path. A further reduction in cost might be achieved by adding more routing stages, but the increased number of routing stages makes computing the optimal routing paths for a given placement of functions very difficult.
Thus, there is a need for a system, an apparatus and a method for routing data over fewer switches and interconnections among reconfigurable logic elements to conserve reconfigurable computational elements without substantially increasing the difficulty of computing routing paths, and for adapting routing resources to dynamically perform complex bit-level operations.

System, apparatus and method for data path routing configurable to perform dynamic bit permutations


A process chamber for semiconductor wafers is formed of multiple compartments. A first compartment is provided for supplying an isolated environment for processing the wafers, and a second compartment is provided, in selective communication with the first compartment, to load and unload wafers from the chamber. The wafer handling equipment is located in the second compartment to isolate it from the process environment, and thus form a clean, non-contaminating, environment for the wafer handling equipment. When the chamber must be cleaned, only the first compartment must be cleaned, as no processing occurs in the second chamber. Therefore, the entire first chamber may be removed for cleaning, and replaced with a clean first compartment to decrease chamber turnaround time during chamber cleaning operations.

1. Field of the Invention
The present invention relates to the field of semiconductor processing, wherein integrated circuits and other devices are formed on a substrate. More particularly, the present invention relates to processing chambers useful for forming microelectronic devices on semiconductor wafers and other substrates.
2. Background of the Art
Semiconductor processing chambers are used to provide process environments for the fabrication of integrated circuits and other semiconductor devices on wafers. To form the integrated circuits on the wafers, they may be sequentially processed, first in a deposition chamber in which a film layer of a metal, dielectric or insulator material is deposited on the wafer, then in a lithographic process chamber wherein a mask is formed on the deposited film layer, and then in an etch chamber where selected portions of the previously deposited film layer are etched. One or more ion implant and passivation steps may also be used to process the wafer. By repetitively depositing a film layer on the wafer, forming a mask over the film layer, and then selectively etching areas of the film layer exposed by the mask, an integrated circuit device may be fabricated on the wafer.
Most prior art semiconductor etch and deposition chambers have several common features. For example, most such chambers are built around a vacuum enclosure in which the wafer is received for processing. A gas inlet having a mass flow controller, and a throttled exhaust coupled to a vacuum pump through a gate valve, communicate with the chamber enclosure to provide the process gas flow and the vacuum conditions necessary for wafer processing. A wafer support member is located within the enclosure to provide a secure resting place for the wafer in the enclosure during the deposition or etch process. A slit valve extends through the enclosure wall to allow a robot blade to place the wafer on, and remove the wafer from, the support member.
To perform the etch or deposition process step in the chamber, a process gas is flowed through the vacuum enclosure. The gas may, as with chemical vapor deposition, deposit a film on the wafer, or the gas may provide disassociated gas atoms which, when exposed to an electric field in the enclosure, are excited into a plasma. The plasma may form an etch plasma to selectively etch a film layer already deposited on the wafer, or the plasma may be used to sputter a target, as with physical vapor deposition, to provide material to form a deposition film layer on the wafer. After the film layer is deposited on the wafer, or after the deposition layer previously formed on the wafer is etched, the process gas is evacuated from the enclosure and the wafer is removed from the enclosure through the slit valve.
During each of the aforementioned processes, a film layer is also formed on the exposed surfaces of the enclosure, including the surfaces of the enclosure walls, the support member, the slit valve, the enclosure inlet, and even within chamber support equipment including the enclosure exhaust, and the pump. The film layer formed on the chamber surfaces may, as with deposition processes, be primarily comprised of the deposition layer material, or, as with etch processes, may be primarily comprised of by-products of etching. This film layer is friable and, if left in place, could form contaminant particles in the enclosure which could deposit on the wafer. Where a contaminant particle of sufficient size deposits on a wafer, one or more semiconductor devices being formed on the wafer will be defective. Therefore, the enclosure must be periodically cleaned to remove these contaminants.
To clean the interior surfaces of the chamber, the cover, or another access panel, of the vacuum enclosure is removed to expose the interior surfaces of the enclosure. The film layer formed on the interior walls and other surfaces of the enclosure is then cleaned with water and/or other materials. Additionally, the other chamber components that may be exposed to the process environment, such as the vacuum pump and the throttle valve, are also removed from the chamber so that the interior pump and valve surfaces may be cleaned. After cleaning, the pump, valves and cover are replaced, and the enclosure is again pumped down to the operating pressure. Because water is used to clean the enclosure surfaces, and water is adsorbed on the metallic enclosure surfaces during the cleaning process, the water must be removed from the enclosure before a satisfactory, stable, vacuum pressure can be maintained in the chamber. Therefore, the chamber is "baked out", at an elevated temperature, to help drive the water from the enclosure surfaces and thus provide a "dry" enclosure environment in which a stable vacuum may be maintained. This bake out period typically lasts at least 8 hours.
The time required to clean and bake out the process chamber is "down time" for the user of the process chamber, because no wafer processing can occur in the chamber during these periods. The amount of chamber down time is further compounded when the process chamber is coupled to multiple other process chambers through a transfer chamber, and the process chamber slit valve must be cleaned. The slit valve must be open during at least a period of the time it is being cleaned. Because the process chamber cover is removed to provide access to the slit valve, the open slit valve communicates ambient conditions to the transfer chamber when it is cleaned. Additionally, water or other materials may contact the transfer chamber surfaces when the slit valve is open during cleaning of the slit valve or chamber, thereby necessitating bake out of the transfer chamber to achieve a stable vacuum after the process chamber is cleaned and resealed. During the period of time that the slit valve is open to the transfer chamber, communication between the transfer chamber and all of the other process chambers must be interrupted to ensure that the cleaning of the one process chamber does not contaminate any of the other process chambers linked to the transfer chamber. Therefore, each of the other process chambers linked to the transfer chambers cannot be used while the process chamber slit valve is being cleaned, or, only those wafers already placed in the other process chambers at the time the slit valve is opened can be processed, and those wafers cannot be removed from the other process chambers until the slit valve is closed to isolate the transfer chamber and the transfer chamber is pumped down and, if necessary, baked out.
In addition to the down time attributable to the cleaning and baking out of the process chamber, many chamber maintenance procedures contribute to chamber down time. For example, servicing of the pump and the pump throttle valve often contributes to down time. In the typical prior art process chamber, the throttle valve is located intermediate of the chamber enclosure and the pump. If the throttle valve must be serviced, or must be cleaned without the need to clean the pump, the pump must still be removed to provide access to the throttle valve. The time needed to remove the pump and the throttle valve is substantially greater than would be necessary to remove the throttle valve alone, and this time difference contributes to chamber downtime. Additionally, once the pump is removed from the chamber, and the interior surfaces thereof are exposed to the atmosphere, the pump itself must be baked out or otherwise stabilized before the pump can maintain a stable vacuum pressure.
The existence of moving parts within the chamber enclosure, such as the intermediate wafer support used to transfer the wafer from a robot blade to the support member, are also a source of chamber down time. The moveable parts within the chamber enclosure receive a deposition or contaminant layer during the use of the chamber because they are exposed to the process environment within the chamber. This contaminant layer is a primary source of particle contaminants on the wafer because the movement of these parts tends to free portions of the contaminant layer deposited thereon during processing. Therefore, these surfaces must be periodically cleaned which increases the time needed to clean the chamber.
One prior art device known to applicants maintained a process environment in a separate compartment from the substrate loading environment, and thus at least partially isolated the process environment from the substrate loading equipment used to position the substrates on a support member. This multi-station device, known as an Eclipse sputter tool which has been available from MRC, included a large main chamber connected, through a fire wall, to a plurality of separate processing stations. Each processing station was located on the exterior of the firewall over a chamber aperture. A plurality of substrate heaters were located within the main chamber, and each heater was dedicated to a particular processing station. A large rotatable transfer plate, having a plurality of apertures therein, was located substantially parallel to the firewall. A substrate could be supported within each of the apertures in the rotating plate, so that each substrate could be moved within the main chamber to be positioned in alignment with each of the firewall apertures, and thus in alignment with each of the processing stations.
The MRC multi-station tool was used to sequentially process substrates through one or more of the processing stations, wherein a sputter environment is maintained in each of the processing stations. In operation, the substrates were loaded into the apertures in the rotating plate at a load position, and rotated through the entire multi-station tool for processing. To perform the processing steps on the substrates, the substrates are first aligned over the individual processing stations, and the substrate heaters were moved from a retracted position within the main chamber to an extended position. The heaters included a plate portion, which engaged the backside of the substrates within the rotating wall apertures to heat the substrates, and an extending annular wall, which engaged against the rotating plate and pressed the rotating plate against the firewall. Seals were provided at the interface of the annular wall against the rotating plate, and between the rotating plate and the firewall, to create a sealed station for the sputter process. Once all of the heaters were moved into their extended positions, a sputter deposition environment would be created in each of the process stations. After the process was completed in the process stations, each of the heaters were retracted from their respective process chambers and the rotating plate was rotated to position the substrates at the next processing station.
The configuration of the MRC multi-station tool has several inherent limitations. In particular, the tool is inherently prone to cross-contamination between the stations, because a portion of the rotating plate is exposed to each process environment as the substrates are rotated for processing in each of the processing stations. Thus, where different materials are deposited on the substrates in different processing stations, impurities, consisting of materials other than those present in the specific processing stations, can enter the main chamber when released from the rotating plate. Additionally, trace amounts of the process environment maintained in each of the processing stations would be discharged into the main chamber when the heaters are retracted from the individual processing stations. These trace amounts of contaminants commingle and build up in the main chamber and in the process stations, to the point where the entire multi-station tool, including the large main chamber, must be cleaned to prevent contamination of the process environments maintained in the individual processing stations. Finally, the tool is slow in operation, because throughput is limited by the slowest process being performed in the tool.
There exists a need in the art for a processing chamber in which the turnaround time for chamber cleaning is reduced, and an arrangement wherein multiple chambers may be connected to a transfer chamber yet the cleaning of a given chamber does not require other chambers connected to the transfer chamber to be shut down for the cleaning of the process chamber.

Compartmentalized substrate processing chamber


According to the inventive photomask, a light shielding pattern as well as a high reflection film are formed at one major surface side of a transparent substrate. Thus, a focal position in a resist film with respect to light directly passing through the high reflection film is separated from a focal position in the resist film with respect to light multiple-reflected by the high reflection film along the thickness direction of the resist film, whereby the depth of focus is enlarged as the result.

1. Field of the Invention
The present invention relates to a photomask, which is employed for working a workpiece such as a semiconductor wafer through a lithographic technique.
2. Description of the Prior Art
FIG. 9 is a schematic block diagram of an exposure apparatus including a photomask which is generally used in a photolithographic process, and FIG. 10 is an enlarged view of its essential part.
As shown in these FIGURES, light L.sub.1 output from a light source 1 is focused by a lens system 2 and emitted onto a photomask 3. In the photomask 3, a light shielding pattern 5 is formed on one major surface of a transparent substrate 4, so that light entering a region corresponding to the light shielding pattern 5 is out off within light L.sub.2 which is incident upon the photomask 3, while light entering the remaining region is transmitted. Light L.sub.3 selectively transmitted through the photomask 3 is collected within a resist film 8 which is formed on a substrate 7 serving as a workpiece, through a projecting lens system 6 of a magnification m, for example. Thus, the resist film 8 is partially photosensitized so that the mask pattern is transferred onto the resist film 8.
The conventional photomask 3 is formed in the aforementioned manner, and light L.sub.3 selectively transmitted through the photomask 3 forms an image on a focal plane 9 including a converging point P (plane perpendicular to the optical axis of the lens system 6 through the converging plane P) through the lens system 6. In this case, a prescribed depth of focus DOF expressed in the following equation is recognized in the lens system 6 with respect to light of a wavelength .lambda., assuming that NA represents its numerical aperture: ##EQU1##
Since the resist film 8 is substantially photosensitized within the range of the aforementioned depth of focus DOF about the focal plane 9 along the thickness direction of the resist film 8, it is preferable that the value of the depth of focus DOF is sufficiently large with respect to the thickness of the resist film 8.
With recent refinement of LSI, however, the numerical aperture NA tends to increase in consideration of the converging ability of the lens system 6. Consequently, the depth of focus DOF tends to decrease to the contrary. In a current manufacturing process for LSI, a lens system 6 having a numerical aperture NA of about 0.54 may be used for ultraviolet rays of 436 nm in wavelength .lambda.. for example, and in this case, the depth of focus DOF is about 1.5 .mu.m from the above equation (1). On the other hand, the thickness of the resist film 8 is also about 1.5 .mu.m, substantially equally to the depth of focus DOF. Therefore, accuracy is required for the exposure apparatus in order to correctly locate the resist film 8 within the depth of focus DOF, while accuracy is also required for an operation for setting the workpiece, and a defectively photosensitized region is caused in the resist film 8 upon merely a slight reduction of such accuracy.


The present invention relates to methods for measuring endogenous cytokines in blood. The method accurately measures the cytokines in the blood in the presence of substances that bind the cytokines thereby causing the measurement of the cytokines by conventional methods to give inaccurate results. The present invention also includes the non-invasive measurement of cytokines in biological fluids such as saliva and nasal secretions. Finally, the present invention allows one to monitor the level of cytokines in the blood during treatment of a human or animal with cytokines.

As used herein, the term "cytokine" is defined as growth factors secreted by immune or other cells, whose action is on cells of the immune system, such as, but not limited to, T-cells, B-cells, NK cells and macrophages. Representative cytokines include, but are not limited to, the group consisting of interleukin 1.alpha., interleukin-1.beta., interleukin-2, interleukin-6, interferon-alpha, interferon-gamma, tumor necrosis factor-.alpha., growth factors, such as TGFB, NGF, EGF, and oncogenes such as c-myc and c-fos. The term "EIA" means any immunoassay utilizing enzymes as the label. The term "endogenous cytokines" as used herein, means cytokines that are produced in vivo and normally circulate in the blood and various other biological fluids. The term includes prohormones which are larger molecular weight forms of cytokines which have not yet undergone post-transcriptional modification.
The impact of a variety of factors, including behavioral and environmental stress, on health and on susceptibility to diseases such as AIDS, cancer and autoimmune disease, is thought to be mediated by the immune system (Ader, R. et al., eds., PSYCHONEUROIMMUNOLOGY, Second Edition, Academic Press, New York (1991)). However, the effects of many of these influences on the function of the immune and host defense systems has been difficult to assess with certainty. This is due, in part, to the fact that most methods of evaluating the activity of the immune system focus on blood components, whether serum or cells.
A newly emerging field known as psychoneuroimmunology seeks to define, in a more mechanistic manner, the way in which biobehavioral factors are internally transduced to impact on the immune system and thereby influence susceptibility or resistance to a variety of pathological processes. Biobehavioral factors such as stress may be positive or negative risk factors for a pathologic outcome (Maier, S. F. et al., BRAIN BEHAV. IMMUN. 2: 8791 (1988)). It is thought by some researchers that a positive or negative attitude in humans may be a significant factor contributing to the overall host response in cancer, AIDS, or autoimmunity (see, for example, Ader et al., supra).
Our ability to evaluate and quantify discrete components of the immune system in a single individual over time (critical for monitoring the onset and/or treatment of diseases associated with AIDS, for example) has been elusive (Kiecolt et al., BRAIN BEHAV. IMMUN. 2: 67-78 (1988); Glaser, R. et al., BRAIN BEHAV. IMMUN. 1: 107-112 (1987)). The study of behavioral strategies that can be enlisted in the modulation of the immune system requires readily available analytical tools that can be used by a broad spectrum of investigators, including those not necessarily sophisticated in complex in vitro immunological techniques. Such methods are clearly lacking at present.
One method used widely in psychoneuroimmunology research is the stimulation of lymphocytes in vitro by mitogens, known also as lymphocyte blastogenesis or the lymphocyte transformation test (Maluish, A. E. et al., MANUAL OF CLINICAL LABORATORY IMMUNOLOGY (3rd Ed.), Rose, N. R., et al., (eds.), 274-281, (1986)). This method involves culture of lymphocytes separated from blood for several days in vitro in the presence of varying doses of mitogens. These mitogens are typically plant-derived or microorganism-derived non-specific activators of lymphocyte -proliferation. The ability of the cultured lymphocytes to incorporate .sup.3 H-thymidine (a well-known measure of DNA synthesis and cell growth) is generally used as a measure of the cells' response. This procedure is highly variable and technician-dependent, and is influenced by a number of unknown factors including the microenvironment provided by the subject's serum if incorporated in the assay.
In contrast to the more classic immunoassays for endocrine hormones, the absence of an established baseline response makes comparison between laboratories, and even within a laboratory, very difficult. However, the lymphocyte transformation test does provide functional information about the immune system because the test examines the response capacity of an entire class of cells, either T or B lymphocytes, depending upon the mitogen used. Unfortunately, the imprecision of the assay greatly diminishes its utility.
A second assay commonly used in psychoneuroimmunology research measures natural killer (NK) cell activity (Herberman, R. B., MANUAL OF CLINICAL LABORATORY IMMUNOLOGY (3rd Ed.), Rose, N. R., et al. (eds.), 308-314 (1986); Irwin, M. et al., BRAIN BEHAV. IMMUN. 1: 98-104 (1987); Jemmott, J. B. 3d, J. BEHAV. MED. 13: 53-73 (1990)). Again, this assay suffers from many of the shortcomings noted above. One reason this assay has become popular is the relative ease of its performance compared to most antigen-specific or antibody-dependent cellular cytotoxicity assays. However, compared to immunoassays commonly used for endocrine hormones, it still ranks as a rather difficult bioassay to perform.
The NK cell assay is based on the ability of a class of white blood cells to spontaneously lyse target cells, typically from an appropriately sensitive tumor cell line, which have been pre-labeled with .sup.51 Cr, thereby releasing the radioisotope into the medium. This assay lacks a quantifiable baseline, and comparisons between individuals is based on the differences in lysis effected by serial dilutions of a blood cell sample. The precise relationship between cells with NK function and the better known classes of leukocytes and lymphocytes is still unclear. Furthermore, the role of NK cells in immunological function and host defense to cancer or infectious disease is not firmly established.
A third approach to monitoring the immune system that has grown in popularity is the enumeration of lymphocyte subsets by flow cytometry using antibodies specific for cell-surface markers (Ault, K., MANUAL OF CLINICAL LABORATORY IMMUNOLOGY (3rd Ed.), Rose, N. R., et al., (eds.), 247-253 (1986)). This approach provides a snapshot of the distribution of various lymphocyte classes in the circulation, but does not provide functional information about any of the cells. Because many psychobiological studies involve a pre-treatment, treatment and post-treatment design, s the assay suffers from the disadvantage that some changes in cell numbers may be too rapid and transient to be meaningful. In contrast, the long-term status of circulating lymphocyte subsets may be too stable to provide an accurate measure of a response to a mild stimulus. The approach of enumerating subsets is thus more appropriate for examination of more permanent changes that occur in major medical illnesses, such as the loss of CD4.sup.+ T cells in AIDS. Therefore, the utility of this method for measuring the response of the immune system to behavioral factors is limited.
A fourth approach, which has the distinct advantage of simple and non-stressful sampling, involves measurement of the secretory immunoglobulin, IgA, in the saliva (Johnson R. B., Jr. et al., J. IMMUNOASSAY 3: 73-89 (1982); Stone, A. A. et al., J. HUMAN STRESS 13: 136-140 (1987); Jemmott, J. B. 3d et al., BEHAV. MED. 15: 63-71 (1989); Jemmott, J. B. 3d et al., J. PERS. SOC. PSYCHOL. 55: 803-810 (1988); Jemmott, J. B. 3d et al., LANCET 1: 1400-1402 (1983)). The total concentration of salivary IgA reflects the presence of a large collection of antibodies of unknown antigen specificity. Furthermore, it is not clear how total IgA levels in saliva relate to the overall dynamics of the immune system. IgA antibodies are associated with mucosal surfaces and are thought to protect these surfaces from infection. Consequently, secretory IgA is found not only in saliva but also in tracheobronchial secretions, colostrum, milk and genitourinary secretions. The utility of monitoring secreted IgA as a useful index of activity of the immune system as a whole has been questioned (Stone et al., supra; Jemmott et al., supra).
Importantly, for testing behavioral factors, such as psychological stress on the immune system, it is particularly important to be able to sample a body fluid in a non-stressful manner. For example, obtaining a blood sample by venipuncture may itself induce physiological changes which could contaminate the data obtained. Thus, a method which would allow measurement of salivary levels of a cytokine or other product of the immune system would have several major advantages over existing approaches, such as (a) eliminating the risk and stress associated with phlebotomy; (b) serving as a window into the internal milieu; (c) allowing simple "at home" collection; (d) permitting a dynamic assessment over time; (e) providing an essential new tool for the evaluation of brain/immune system interactions; (f) serving as a measure which will assist in evaluating the impact of stress on health and (g) providing a measure that may be relevant to the onset of disease after initial pathogenic events, such as HIV infection in AIDS.
Two regulatory molecules of the immune system are interleukin 1 and 2 (IL-1 and IL-2). The ability of IL- 1 and IL-2 to modulate a cytokine "cascade" and the concomitant cell proliferation, differentiation and effector function of lymphoid cells has been characterized in detail (see, for example, Kampschmidt, R. F., J. LEUK. BIOL. 36: 341-355 (1984); Smith, K. A., ANN. REV. IMMUNOL. 2: 319-333 (1984)).
These two molecular signals are apparently not limited to action within the immune system, as recent studies indicate that both of these cytokines act as homeostatic regulators outside the immune system. For example, IL-1 has been shown to act as a potential modulator of the hypothalamic-pituitary-adrenal axis (Besedovsky, H. et al., SCIENCE 233: 652-654 (1986); Bernton, E. W. et al., SCIENCE 1987: 519-521 (1987)), while IL-2 has been shown to affect Leydig cell steroidogenesis (Gou, H. et al., ENDOCRINOLOGY 127: 1234-1239 (1990)). Studies have demonstrated that IL-1 and IL-2 directly (without the presence of macrophages or T-cells) inhibited the in vitro and in vivo growth of hormone-dependent human breast cancer cells (Paciotti, G. F. et al., MOL. ENDOCRINOL. 2: 459-464 (1988); Paciotti, G. F. et al., ANTICANCER RES. 8: 1233-1240 (1988); Paciotti, G. F. et al., ANTICANCER RES. 11: 25-32 (1991)). It appears, therefore, that these cytokines not only affect classical autocrine/paracrine loops within the immune system, but also affect endocrine circuits and may therefore modulate interactions between the endocrine and immune systems.
For IL-1 and IL-2 to play roles as "endocrine-like" hormones, they must exist in sufficient quantities to reach and affect their hypothesized target sites. Thus, ascertaining the biological basis of an endocrine action for such signal molecules traditionally thought to belong to the immune system, depends on our ability to detect and monitor, in a quantitative manner, the endogenous concentrations of these molecules. Conventional methods of measuring IL-1 and IL-2, as well as other cytokines, directly in the blood have been unsatisfactory.
To date, the study of IL-1 and IL-2 has been concerned primarily with their role in stimulating lymphocyte proliferation and helper and effector function in the adaptive immune response and other forms of host defense. As a result of this focus, study of these cytokines has been limited to stimulation of cells cultured in vitro, or the measurement of blood cytokine levels in vivo in immunological diseases. Recent studies indicate that IL-1 should be considered an "endogenous" component of the circulation; its concentration can vary in a number of "real life" situations.
Generally, in viewing IL-1 and IL-2 or other cytokines as measures of immunocompetence in vivo, investigators have focused on large changes in concentration under severe pathophysiological conditions such as leukemia and arthritis. Furthermore, reports of circulating cytokine levels have been concerned with the elevation in patients compared with controls, while paying little attention to the fact that IL-1 and IL-2 were also detectable in normal subjects and might be subject to modulation by a variety of subclinical factors (Michie, H. R. et al., NEW ENG. J. MED. 318: 1481-1486 (1988); Grau, G. E. et al., LYMPHOKINE RES. 7: 335 (1988); Shenkin, A. et al., LYMPHOKINE RES. 7, 333 (1988)).
In addition to measurement of cytokines in serum or plasma, various cytokines have been detected in other biological fluids. For example, Kimball, E. C. et al., (J. IMMUNOL. 133: 256-260 (1984)) reported IL-1 bioactivity in human urine. Tamatani, T. et al., (IMMUNOLOGY 65: 337-342 (1988)) disclosed the presence of IL-1.alpha. and IL-1.beta. in human amniotic fluid, using chromatographic and bioassay methods. The same group used enzyme immunoassays to measure IL-1.alpha. and IL-1.beta. in human amniotic fluid (Tsunoda, H. et al., LYMPHOKINE RES. 7: 333 (1988)). Wilmott, R. W. et al., (LYMPHOKINE RES. 7: 334 (1988)) measured IL-1.beta. (by EIA) and IL-1 bioactivity in human bronchoalveolar lavage fluid in cystic fibrosis compared to other diseases. Khan, et al. (MOL. CELL. ENDOCRINOL. 58: 221-230 (1988)) reported that high levels of IL-1-like bioactivity could be demonstrated in human ovarian follicular fluid. Lymphotoxins have been reported in blister fluid of pemphigoid patients (Jeffes, E. W. et al., J. CLIN. IMMUNOL. 4: 31-35 (1984)). IL-1 has also been reported in human sweat (Didierjean, et al., "Biologically active interleukin 1 in human eccrine sweat: Site dependent variations in .alpha./.beta. ratios and stress-induced increased secretion," CYTOKINE 2: 438-446 (1990)).
IL-1 has been reported to be found in the cerebrospinal fluid (CSF) of cats (Coceani, F. et al., BRAIN RES. 446: 245-250 (1988)) and humans (see, for example, Peter, J. B. et al., NEUROLOGY 41: 121-123 (January 1991)). When Peter et al. (supra) examined IL-1.beta. and tumor necrosis factor (TNF) in CSF and serum of multiple sclerosis patients and normal controls, they concluded that the levels of these cytokines in these two fluids were not of prognostic or diagnostic utility. Westacott, C. I. et al., (ANN. RHEUM. DIS. 49: 676-681 (1990)) used immunoassays to measure cytokines in synovial fluid of patients with rheumatic disease (EIA for IL-1.beta.; RIA for IL-2, TNF, IFN alpha and gamma).
A factor with IL-1-like bioactivity was detected in the gingival fluid of clinically normal humans (Oppenheim, J. J. et al., TRANSPLANT. PROC. 14: 553-555 (1982)), the activity being higher in inflamed than non-inflamed gingival regions. The gingival fluid factor exhibited molecular weights corresponding to both IL- I and epidermal thymocyte-activating factor (Charon, J. A. et al., INFEC. IMMUN. 38: 1190-1195 (1982)). Studies by Jandinski and colleagues using EIA (Jandinski, J. et al., J. DENT. RES. 67: 2307 (1988); Jandinski, J. et al., J. DENT. RES. 68: 526 (1988); Jandinski, J. et al.. J DENT. RES. 68: 1233 (1988)) reported the presence of IL-1.alpha. in periodontal tissue, while IL-1 predominated in gingival crevicular fluid of patients with periodontal disease. A more recent study (Kabashimi, H. et al., INFEC. IMMUN. 58: 2621-2627 (1990)) utilizing polyclonal antisera to recombinant human IL-1.alpha. and IL-1.beta. and measurement by Western blotting, disclosed that the majority of the IL-1 bioactivity found in gingival crevicular fluid of patients with chronic inflammatory periodontal disease was IL-1, generally considered the membrane-bound form of IL-1. The suggestion was made that the IL-1 was derived by enzymatic cleavage from the cell surface. In this latter study, special care was taken to avoid contamination of the gingival fluid with saliva. These facts argue strongly against a salivary origin for the gingival fluid IL-1.
As can be seen from the foregoing overview of the literature, there have been many attempts to measure endogenous cytokines in blood and other body fluids. However, in reviewing these reports, it is apparent that there is wide variation in the reported results with regard to cytokine concentration in the blood and to fluctuations of cytokine concentration in the blood.
Many reports indicate that cytokines (i.e., IL-2) are not detectable in normal subjects using immunoassays. It is possible that circulating IL-2 may be bound by the well-described soluble IL-2 receptor. The site of attachment may interfere with recognition by the capture antibody of a sandwich assay system, which would make IL-2 appear undetectable. Alternatively, even if the molecule is captured, the detection by the second antibody may be prevented by steric hindrance by the binding of both the capture antibody and the soluble IL-2 receptor to IL-2. In effect, there may not be sufficient space to permit the binding of yet a third large protein. The key element is that the design of these sandwich ELISA assays suggests that they may only pickup a fraction of the total.
It is possible that some assay procedures detect very little cytokine, whereas others pickup none at all. This difference may be related to the assay system or to the cytokine or both. The problem has been reported by the observations of Cannon, J. G., et al., LYMPHOKINE RES., 7: 457-465 (1988), in which the authors show that some plasma substance inhibited the assay, effecting detection. In this study, the authors recommend chloroform extraction of plasma to remove interfering substances. It is not clear from this study if the plasma factors simply effect the performance of the assay or are related to the cytokine itself. This question was further described by Capper, S. J., et al., CYTOKINE 2: 182-189 (1990). Capper, S. J., et al. show that IL-1 .alpha. and .beta. are bound by proteins and that the dissociation of these molecules from these serum binding proteins by acidifying the plasma changes the detectable levels. The problem of masking appears to be unique to biological samples collected from in vivo sources; in vitro cell culture supernatants do not contain large quantities of serum binding proteins.
The best example of a cytokine "binding protein" may be inferred from the data describing a soluble IL-2 receptor found in the circulation. This molecule has been shown to be immunologically similar to the low affinity IL-2 receptor on T-cells, "Tac". Its presence in the circulation, free of the T-cell, would strongly argue that it can no longer be a receptor capable of transmitting signals from outside the cell to inside the cell. However, these data do not address the ability of this molecule to still bind IL-2. We would argue that IL-2 in the circulation is bound by this protein, and it is this bound complex which essentially makes the endogenous IL-2 undetectable by "sandwich" assays. Other cytokines (e.g., IL-1) may be bound to other carrier molecules in serum that effectively masks their detection.
In addition, while various cytokines, including IL-1, have been reported in certain normal or pathological biological fluids, there have been no reports of cytokines or lymphokines in saliva or nasal secretions. In fact, a paper reporting a study of the pharmacodynamics of interferon (Diez, R. A. et al., J. INTERFERON RES. 7: 553-557 (October 1987)) stated that ". . . at present, whether interferon is present in saliva and nasal secretion is unclear."
It would be of great benefit if one could easily, accurately and reproducibly measure the concentrations of various endogenous cytokines in the body fluids. This would create a useful window not only into the immune system but into a myriad of physiologically interacting processes. Such tools would be useful in a variety of settings, allowing the collection of data of importance to basic medical sciences, clinical medicine, epidemiology and the forensic sciences.
What is needed is a reliable method of measuring endogenous cytokines in blood which will result in an accurate blood concentration of the cytokine independent of binding proteins which may be bound to the circulating cytokine. In addition, ability to measure cytokines in a biological fluid such as saliva or nasal secretions would simplify the analysis of an individual's immune system, possibly supplanting the need to perform prolonged, tedious and highly variable assays of these cells' behavior in culture.

Method for measuring endogenous cytokines


An optical fiber cable (20) includes provisions in a core thereof for preventing the flow of water longitudinally along the core and for preventing freezing of such water. The provisions for preventing freezing of water within the core, which could effect adversely the optical fibers, includes an antifreeze material. Each of two tapes may be impregnated with an antifreeze material such as propylene glycol, for example, and used to provide a laminate with a superabsorbent powder therebetween. Advantageously, the cable may have suitable flame retardance so that it may extend from an outside manhole to distribution points within a building.

In the cable industry, it is well known that changes in ambient conditions lead to differences in water vapor pressure between the inside and the outside of a plastic cable jacket. This generally operates to diffuse moisture from the outside of the cable to the inside of the cable. Eventually, this will lead to an undesirably high moisture level inside a core of the cable, especially if a plastic jacket is the only barrier to the ingress of the moisture. High levels of condensed moisture inside a cable core may have a detrimental effect on the transmission characteristics of an optical fiber cable and a metallic conductor cable.
Furthermore, water may enter the cable because of damage to the cable which compromises its integrity. For example, lightning and rodent attacks or mechanical impacts may cause openings in the sheath system of the cable to occur, allowing water to enter and, if not controlled, to move longitudinally along the cable into splice closures, for example.
Cables for transmitting communications signals must meet industry standards with respect to waterblocking provisions. For example, one industry standard requires that there be no transmission of water under a pressure head of one meter in one hour through a one meter length of cable.
In the prior art, various techniques have been used to prevent the ingress of water through the sheath system of a cable and along the core. For example, a metallic shield which often times is used to protect a metallic conductor cable against lightning and rodent attacks is provided with a sealed longitudinal seam.
Because lightning strikes may cause holes in a metallic shield, it is not uncommon to include additional provisions for preventing the ingress of water into the core. Waterblocking materials have been used to fill cable cores and to coat portions of cable sheath systems to prevent the movement longitudinally thereof of any water which enters the cable. See U.S. Pat. No. 4,176,240 which issued on Nov. 27, 1979, in the name of R. A. Sabia. The use of a filling material, in the form of a grease, causes housekeeping problems, inhibits line speeds because of the need to fill carefully interstices of the cable core, and presents problems for field personnel during splicing operations, for example.
Also, some filling materials have adversely affected the mutual capacitance of the core. This problem has been overcome by a filling material comprising a mixture of a hydrophobic powder in the form of water repellent treated calcium carbonate and a hydrophilic powder in the form of at least one high molecular weight resin rapidly hydratable to form a viscous solution. See U.S. Pat. No. 4,002,819.
Waterblocking provisions inside the core may be other than a filling material. See U.S. Pat. No. 4,946,237 which issued on Aug. 7, 1990 in the names of C. J. Arroyo and P. F. Gagen. A longitudinally extending waterblocking member inside a core tube may take several forms. For example, it may comprise a laminate comprising a powder captured between two tapes. Or, it may comprise a substrate tape which is impregnated with a material. When exposed to water, the impregnating material reacts to swell and causes the tape to prevent the passage of water through the sheath system toward the core and its migration in a direction longitudinally along the cable. In one embodiment, the impregnating material comprises a film of a water swelling or so-called superabsorbent material. In another embodiment, a tape may be treated with a paste comprising a superabsorbent material. The impregnating material may be a polyacrylic acid having a saponification in a relatively wide range or it may be a polyacrylamide. Also, the impregnating material may comprise blends or salts of polyacrylic acid or polyacrylamide, or copolymers or derivatives of the acrylic acid and the acrylamide. Further, the waterblocking provisions within the core may comprise one or more yarns which have been impregnated with a superabsorbent material or which comprise superabsorbent fibers. Also, the waterblocking provisions in the core may comprise a waterblocking tape, which may engage an inner surface of the core tube, and a waterblocking yarn or yarns.
Lately, optical fiber cables have made great inroads into the communications cable market. Although the presence of water within an optical cable may not be detrimental to the performance of optical fibers of the cable, passage of the water within the cable should be prevented as its presence at connection points or terminals may cause problems. For example, the formation of and retention of ice around the optical fibers provide a microbending crushing effect which is known to increase undesirably the attenuation. Thus, protective sheaths must also be water impermeable to prevent or minimize ingress of water. However, even when efforts are made to prevent water ingress, sheath damage may provide pathways for water into cable and upon freezing, attenuation problems will still result. Thoughts have been given, therefore, to the provision of means which will prevent the crushing action of ice upon optical fiber, but to date solutions to the problem have not met with wide acceptance.
Another problem relates to the use of riser cables which connect interoffice and intercity trunks. Such cables include portions which provide vertical riser distribution between two or more floors of a building. Typically indoor optical fiber cables are all air core while outdoor cables include filling materials in the core to provide resistance to water penetration. Desirably, the use of one cable to extend from an outside manhole into a building and upon a riser shaft would result in substantial cost savings because of the elimination of the need for additional splice locations. In order to use one length of cable to extend from a splice location in a manhole outside a building into the building and then to distribution points, the cable must include suitable waterblocking and freeze prevention provisions to satisfy outside requirements which do not compromise the fire retardance properties of the cable needed for internal building use.
Cable manufacturers have resorted to the use of superabsorbent materials which provide the desired resistance to water penetration while not degrading the flame resistance of the cable. As mentioned hereinbefore, in some cables, superabsorbent tapes have been disposed inside the cable core. It has been found that the use of a superabsorbent tape in an optical fiber cable core may result in an increased microbending loss in the fibers because of freezing of the activated superabsorbent gel.
What is needed and seemingly what is not available is an optical fiber cable which includes protection against the flow of water along the cable and which includes provisions for protecting the optical fibers against a freezing environment. Also desirable is a cable which has sufficient flame retardance so that the cable may be used inside buildings such as in risers, for example.

Optical fiber cable which includes waterblocking and freeze preventing provisions


Techniques or designs of circuits to correct distortions in signals transported over a high-speed digital connection between a video source (e.g., a PC or a DVD player) and a digital monitors (such as LCDs) are disclosed. According to one aspect of the present invention, a distorted signal is corrected by an interface circuit that oversamples the incoming signal with clock pulses or signals generated using a phase lock loop (PLL) from a clock seed signal. These clock signals possess different phases that are shifted from each other. In order to support a wide range of data rate, a programmable DPLL is used to produce a number of different ranges of clock frequency (e.g., 4 ranges). In addition, to avoid data phase shift, a delay locked loop (DLL) is used to compensate for the phase shift. A phase detection logic is also used to extract phase information from the over-sampled data. The phase information is fed back to the DLL.

1. Field of the Invention
The present invention generally relates to the area of integrated circuit designs, and more particularly, relates to a circuitry design and method for preventing signal distortions in transmission between a signal source (e.g., a computer) and a digital display (e.g., a liquid crystal display or LCD).
2. Description of the Related Art
One of the examples of digital displays is liquid crystal displays (LCDs) which is the most common application of liquid crystal technology. From the ubiquitous wrist watch and pocket calculator to an advanced VGA computer screen, this type of display has evolved into an important and versatile interface. A liquid crystal display includes an array of tiny segments (called pixels) that can be manipulated to present information. This basic idea is common to all digital displays, ranging from simple calculators to a full color LCD television.
An LCD is made primarily of two glass plates with some liquid crystal material between them. There is no bulky picture tube. This makes LCDs practical for applications where size (as well as weight) are important. Moreover, LCDs use much less power than their cathode-ray tube (CRT) counterparts. Many LCDs are reflective, meaning that they use only ambient light to illuminate the display. Even displays that do require an external light source (i.e. computer displays) consume much less power than CRT devices.
Different from a CRT that requires an analog signal, an LCD requires digital signals to be continuously fed, wherein the digital signals are organized into individual pixels, rows of pixels, and full-page frames. Any disturbance or video artifact can cause signal distortions in the digital signals that can be visible on the display. There is a need for techniques to minimize or prevent such signal distortions in the signal transmission between a signal source and a digital display.


Disclosed is a tire stud comprising a stainless steel body with a flange and a blind hole and further comprising a spike installed in said hole, wherein the cross-sectional shape of the hole is different from the cross-sectional shape of the spike at least at one of: the opening, the lower surface of the spike, and a depth between the opening lower surface of the spike; whereby only protrusions of the spike are attached to the side wall of the hole with friction joints where the cross-sectional shape of the hole is different from the cross-sectional shape of the spike.

As is known, studs may be used in tires to improve traction during e.g. winter conditions such as driving on an icy road.
And, as is known, such studs typically comprise a body with a blind hole, into which hole is inserted a spike which remains somewhat protruded from the stud body. Such a spike, then, is that element of the stud which contributes most to the traction provided by the stud.
Commonly, stud bodies are made of steel. This is problematic as steel corrodes, i.e. rusts, during both using tires having steel-bodied studs and during storage of such tires, such as during the summer season when studded tires are not in use but are in storage. Such a problem is made even more pronounced by a practice of applying salt on icy or snowy roads in some countries, whereby corrosion of steel-bodied studs is accelerated when used on salted roads. While such a problem often is attempted to be alleviated by zinc coating of steel studs, such a coating usually wears off very rapidly during use, leaving the studs prone to corrosion.
Corrosion of stud bodies is undesirable both with respect to the mechanical properties of the stud bodies as well as their visual appearance. For example, prolonged corrosion within the hole housing the spike may result in the spike becoming loose and, eventually, coming off from the body. Similarly, corrosion of the outer surface of the stud body increases the risk of the stud coming off from its installation cavity in the tire.
Therefore, there is a need to provide a solution to decrease or preferably prevent corrosion of stud bodies without adversely affecting the other properties of modern-day studs.


A co-processor for performing a matrix multiplication of an input matrix with a data matrix in one step may be provided. The co-processor receives input signals for the input matrix as optical signals. A plurality of photonic memory elements is arranged at crossing points of an optical waveguide crossbar array. The plurality of memory elements is configured to store values of the data matrix. Input signals are connected to input lines of the optical waveguide crossbar array. Output lines of the optical waveguide crossbar array represent a dot-product between a respective column of the optical waveguide crossbar array and the received input signals, and values of elements of the input matrix to be multiplied with the data matrix correspond to light intensities received at input lines of the respective photonic memory elements. Additionally, different wavelengths are used for each column of the input matrix optical signals.

The invention relates generally to a matrix-matrix multiplication, and more specifically, to a co-processor for performing a matrix-matrix multiplication of an input matrix with a data matrix in one step. The invention relates further to a related computer-implemented method, and a computer program product.
Continuous data growth is one of the ongoing trends for enterprise IT (information technology). In order to generate meaningful results, enterprise IT organizations thrive for a more and more intensive usage of the data by continuously better analysis. However, it turned out that classic data analysis techniques are no longer sufficient to analyze the vast amount of unstructured—or better, semi-structured—data. With the proliferation of ultra-high-speed more networks and Internet-connected devices, the world is generating exponentially increasing amounts of data that needs to be processed in a fast, efficient and "smart" way. Science and enterprise IT organizations are increasingly using artificial intelligence (AI) techniques to better understand the available data and generate value out of it. On the other side, it turned out that traditional van-Neumann computing architectures may no longer be sufficient to deal with the ever-growing amount of data, data movements and the related computing requirements.
Especially, AI methods and techniques may require a lot of mathematical operations to the input data, e.g., in the form of matrix-matrix multiplications, often used in, e.g., image recognition/classification, autonomous navigation, and audio analysis in the frequency domain. Such data belong more and more—alongside with speech data, other sound data, as well as input in form of text documents or a mixture of text and image—to the stream of incoming data in classical data centers. The consequence is a continued requirement to process the continuously exponentially growing amount of data and ever increasing processing speed consuming more and more electrical power. Hence, there is a requirement to implement low-power, high-speed data processing devices which may be operated as co-processors to traditional computing architectures. Such devices may be capable of operating at Tera-Multiply-Accumulate per second (TMAC/s) speed.

Photonic in-memory co-processor for convolutional operations

International Business Machines Corporation


An electrohydraulic drilling system for drilling holes in material such as rock utilizing a drill stem connected to a flexible cable. The electrical spark or plasma that creates the electrohydraulic pressure wave is powered by an electrical pulse propagated down the cable from a pulse generator to the drill stem. An advance mechanism on a jackleg support is utilized to move the drill into the rock during the drilling process. The drill stem and cable combination enable holes to be drilled in the roof of tunnels where the floor to roof height is less than the depth of the hole to be drilled. The electrohydraulic process provides higher drilling efficiencies than conventional systems.

1. Field of the Invention (Technical Field)
The present invention relates to a portable drill apparatus and system which utilizes the electrohydraulic technique (the creation of shock wave and pressure wave from an underwater spark or plasma) which provides high drilling rates and is useful for the purpose of drilling shallow holes (a few meters in depth) in underground mines and above ground mining and construction applications. The drill utilizes electrical power from an attached pulse generator to create intense shock waves in the electrode area to crush rock or other material. Water flush is provided through the cable and the drill stem to sweep out the cuttings. The drill support and advance mechanism is utilized to advance the drill through the rock.
2. Background Art
One of the ongoing needs for small drills in the mining industry is the drilling of roofbolt holes for supporting the mine roof and the drilling of explosive holes for inserting explosives, removing the ore from the mine face. Conventional drill technology utilizes a star bit and an air hammer to provide drilling action in drilling the holes. These machines are very noisy, the drill tip needs frequent replacement and the overall efficiency of this system is very poor (near 1%). Perhaps, most significantly, the drill cannot be utilized in areas where the distance from the floor to the ceiling is short (of the order of 1-1.5 meters), because of the need to utilize solid rod for the drilling process. The same is true of drills utilizing a rotary motion for the drilling process. In all of these cases, it is not possible for the drill to drill into the roof for a hole depth that is longer than the drill itself. For example, it is not possible for one of these drills operating in a 1.5 meter floor-to-ceiling height to drill a hole in the roof 3 meters deep. In addition, these drills require significant pressure exercised against the rock by the operator in order to provide the cutting action. This places the operator at risk because of the potential fall of rock from the roof onto the operator during the drilling process.
The electrohydraulic process has been used for some period of time for creating shock waves in water (see U.S. Pat. No. 4,471,405, entitled "Focused Shock Spark Discharge Drill Using Multiple Electrodes," to Moeny, et al.). The '405 Patent teaches the use of a pulse forming line to control power flow into the head of a drill utilizing the electrohydraulic process. The pulse forming line is connected to an array of electrodes which forms a spark array. One of the electrodes of each of the array is connected to the high voltage side of the pulse forming line and the other electrodes are at ground potential. When discharged in a liquid, these electrodes produce intense focused shock waves that can pulverize or fracture rock. By delaying the firing of each group of electrodes, the drill can be steered within the earth. Power can be fed to the pulse forming line either downhole or from the surface.
The significant technology issues that must be solved in order to utilize electrohydraulic (EH) rock crushing for drilling in a mining situation include power control to the electrodes, flashover suppression inside the drill, shock wave control, and electrode erosion. Secondly, the electrical pulse that is delivered to the drill must be controlled so that the plasma that is created in the water has the proper relationship of current with time to create the shock wave or pressure wave for efficient and effective crushing of the rock. However, the hardware must then accommodate this pulse so as to provide the high voltage necessary to achieve breakdown at the drill tip without causing breakdown elsewhere in the portable drill stem, especially in the region near but not at the electrodes.
In order to overcome the problems of the prior art, it is necessary to prevent the rock crushing process itself from also crushing the insulator and thus destroying the operation of the drill. Directing the shock wave to the surface to be crushed, and preventing it from crushing key internal portions of the drill is also required for a successful portable electrohydraulic drill. Further, a system to prevent the rock dust from contaminating the insulator thus leading to high voltage flashover across the insulator and destruction of the insulator is needed. All electrohydraulic plasmas erode the electrodes. The physical process is caused by the interaction of the plasma with the molten electrode material. It is unavoidable for practical purposes. Therefore, means to deal with electrode erosion is also required if the electrohydraulic process is to be used for drilling.


Topical personal care compositions containing amino acids and 4-substituted resorcinols for potentiating glutathione synthesis within skin cells. The compositions can be used to improve skin appearance of chronological aging or photoaging, resulting from exposure to UV light/sunlight, or environmental pollutants. The compositions are also useful for attaining even skin color and reducing pigmentation, age spots and discoloration.

Glutathione (GSH) is a tripeptide that consists of glutamate, cysteine, and glycine. It is present in all mammalian tissues. It is the main anti-oxidant in the living body: it protects cells from oxidation by quenching reactive oxygen species. GSH is believed to play a significant role in protecting cells against the cytotoxic effects of ionizing radiation, heat, certain chemicals, and significantly, solar UV radiation (Tyrell et al., Photochem. Photobiol. 47: 405-412, 1988; Meister, J. Biol. Chem. 263: 205-217, 1988; Meister, Science 200:471-477, 1985). While true in all areas of the body, this is particularly important in the skin, which is so greatly exposed to the damaging effects of radiation, particularly UV radiation, and environmental pollutants. Decrease in the intracellular concentration of glutathione in skin is associated with cell damage, inflammation, skin darkening, discoloration, spots or freckles caused by exposure to ultraviolet radiation, physiological aging, and the like. It is, therefore, highly desirable to enhance the generation of glutathione in skin.
A logical approach would seem to be to provide cells with an exogenous source of GSH (e.g. through ingestion or topical delivery). Unfortunately, GSH is not bioavailable when administered exogenously, i.e. where localized extracellularly, it is broken down into its constituent amino acids (glutamate, cysteine, and glycine) for cellular uptake and synthesis of the GSH tripeptide. Thus, GSH is not directly transported into the cells and therefore does not itself result in an intracellular increase of glutathione. Biosynthesis of GSH occurs in the cell in a tightly regulated manner. The quantity of glutathione in cells depends to a large degree on the availability of cysteine in the cells. Cysteine, a composite amino acid of GSH, may increase cellular levels of GSH, but exposed sulfhydryl group of cysteine renders it unstable and reactive and also causes strong unpleasant odor. Unlike cysteine, cystine can be administered safely; cystine is transported into the cell and converted to cysteine within the cell, the cysteine then being available for intracellular GSH production.
Topical compositions containing various amino acids and other skin care actives have been described, see e.g. Tanojo U.S. Pat. No. 7,300,649B, Laboratoire Filorga product, Schlachter WO 00/03689, Ermolin et al. US2011183040, Garlen et al. U.S. Pat. No. 4,707,354, Muller et al. U.S. Pat. No. 8,361,446, Hermann et al. U.S. Pat. No. 8,241,681. Compositions for potentiating intracellular glutathione production have been described. See e.g. Chiba et al. U.S. Pat. No. 7,740,831, Crum et al (USRE37934, USRE42645, WO2016/033183, and US20050271726); Mammone U.S. Pat. No. 6,149,925, and Perricone US 20060063718.
Cystine is normally derived from the diet. Delivery of cystine from topical compositions, however, is challenging due to its extremely low solubility in biologically acceptable vehicle in a neutral pH range, which is the pH range required for topical application. The solubility of cystine in water is 0.112 mg/ml at 25° C.; cystine is more soluble in aqueous solutions with pH less than 2 or pH above 8.
The present invention is based in part on a surprising finding that a combination of cystine with a specific class of resorcinols achieves a synergistic increase in intracellular glutathione levels, thus counter-acting the drawback of cystine's low solubility at neutral pH. Furthermore, by virtue of including the resorcinol, only 2 out of the 3 amino acids are sufficient to attain synergistic increase in intracellular production of glutathione.

Personal care compositions with glutathione precursor comprising 4-substituted resorcinols and amino acids