Exciting light is projected onto a specimen such as an organic body, and an intensity in at least one wavelength range of fluorescence emitted from the specimen upon excitation by the exciting light is detected. Image data representing a fluorescence image of the specimen is obtained through an operation based on the intensity of the fluorescence. Whether each of pixels forming the fluorescence image is adequate for said operation is determined on the basis of the intensity of the fluorescence of each pixel. The operation is carried out on adequate pixels, which have been determined to be adequate for the operation, to obtain values for the adequate pixels while values which will not visually adversely affect the part of the fluorescence image corresponding to the adequate pixels are allotted to inadequate pixels, which have been determined not to be adequate for said operation.

1. Field of the Invention
This invention relates to a method of and an apparatus for obtaining a fluorescence image on the basis of fluorescence emitted from a specimen such as an organic body upon excitation by exciting light.
2. Description of the Related Art
There has been studied a fluorescence diagnosis system in which exciting light is projected onto an organic body or the like, and information useful for diagnosis is obtained from the intensity or spectral band intensity of fluorescence emitted from the organic body upon excitation by the exciting light. Such a fluorescence diagnosis system includes, for instance, those in which autofluorescence emitted from an organic tissue upon excitation by the exciting light is detected, and those in which fluorescence emitted from an organic tissue which has absorbed a drug for fluorescence diagnosis is detected. Such a fluorescence diagnosis system is generally incorporated in an instrument such as an endoscope, a colposcope, or an operative microscope which is inserted into a body cavity and is used for analyzing conditions of the organic tissue.
At the beginning, an attempt to make a diagnosis on the basis of the intensity of fluorescence emitted from an organic tissue upon excitation by exciting light was made. However, as the relative position between the tissue and the part of the system from which the exciting light is projected onto the tissue such as the distance, angle and the like therebetween changes, the intensity of the exciting light projected onto the organic tissue changes, which results in change in the intensity of the fluorescence emitted from the tissue. Accordingly, the same site of the organic body can emit fluorescence of different intensities depending upon the position of the exciting light projecting part of the fluorescence diagnosis system, which shows that a sufficient diagnostic performance cannot be obtained from the intensity of the fluorescence by itself. Therefore, recently there have been made various attempts to recognize change in the tissue condition on the basis of the fact that the profile of spectral band intensities of the fluorescence changes with change in the tissue condition. For example, a diseased tissue greatly differs from a normal tissue in the ratio of intensity of a green region wavelength component of the fluorescence to intensity of a red region wavelength component of the same. There has been proposed in Japanese Unexamined Patent Publication No. 6(1994)-54792 a fluorescence diagnosis system in which the ratio of intensity of a green region wavelength component to intensity of a red region wavelength component of autofluorescence emitted from an organic tissue to be diagnosed is compared with that of an organic tissue which has been determined to be normal by a different system and whether the organic tissue to be diagnosed is diseased or normal is determined on the basis of the comparison.
Further, we have proposed in Japanese Unexamined Patent Publication No. 10(1998)-225436 a fluorescence diagnosis system in which the intensity in a green wavelength range of fluorescence emitted from an organic tissue is normalized with the intensity of the overall fluorescence (substantially over the entire wavelength range of the spectral bands of the fluorescence) and is compared with that of an organic tissue which has been determined to be normal by a different system, and whether the organic tissue is diseased or normal is determined on the basis of comparison.
However, the intensity of fluorescence of each pixel of an image obtained by taking weak fluorescence emitted from the organic tissue includes noise inherent to the image taking device (e.g., fixed pattern noise, photon shot noise, dark shot noise and read-out noise), noise inherent to the electric processing circuit, noise inherent to the signal transfer system, noise inherent to the optical system (noise due to stray light generated, for instance, by light scattered by dirt or the like adhering to the optical components) and the like, and the intensity of the noise is too large as compared with the intensity of the fluorescence especially for pixels in a region where the intensity of fluorescence is very weak. Accordingly, when the intensity in a green wavelength range of fluorescence emitted from an organic tissue for pixels in a region where the intensity of fluorescence is very weak is normalized by the intensity in a green wavelength range by the intensity of the overall fluorescence, the information obtained by the normalization cannot accurately reflect the condition of the organic tissue since the former intensity and the latter intensity are both very weak and the intensity of the noise components included in the former and latter intensities is too large as compared with the former and latter intensities. When information on such pixels are used as it is in reproduction of an image, the pixels can visually adversely affect observation of the reproduced image.
These problems are common to the fluorescence diagnosis systems in which autofluorescence emitted from an organic tissue upon excitation by the exciting light is detected, and those in which fluorescence emitted from an organic tissue which has absorbed a photosensitive substance for fluorescence diagnosis such as ATX-S10, 5-ALA, Npe6, HAT-D01 or Photofrin-2 (will be referred to as xe2x80x9cfluorescence produced by a photosensitive substancexe2x80x9d hereinbelow) is detected.
In view of the foregoing observations and description, the primary object of the present invention is to provide a method of and an apparatus for obtaining a fluorescence image on the basis of fluorescence emitted from a specimen such as an organic body upon excitation by exciting light in which even if adverse pixels, whose intensities include noise in a large proportion, are included in pixels obtained by taking fluorescence emitted from the specimen upon excitation by the exciting light, a fluorescence image which cannot be visually adversely affected by existence of the adverse pixels can be obtained.
In accordance with one aspect of the present invention, there is provided a method of obtaining a fluorescence image comprising the steps of projecting exciting light onto a specimen such as an organic body, detecting an intensity in at least one wavelength range of fluorescence emitted from the specimen upon excitation by the exciting light, and obtaining image data representing a fluorescence image of the specimen through an operation based on the intensity of the fluorescence, wherein the improvement comprises the steps of
determining whether each of pixels forming the fluorescence image is adequate for said operation on the basis of the intensity of the fluorescence of each pixel, and carrying out said operation on adequate pixels, which have been determined to be adequate for said operation, to obtain values for the adequate pixels while allotting to inadequate pixels, which have been determined not to be adequate for said operation, values which will not visually adversely affect the part of the fluorescence image corresponding to the adequate pixels.
For example, whether each of pixels is adequate for said operation may be determined by comparing the intensity of fluorescence for the pixel with the value of noise for the pixel which is generated by means for measuring the intensity of fluorescence and has been measured and stored in advance.
When carrying out image processing on the image data, the image processing may be carried out only on the adequate pixels.
The specimen may be an organic body and the fluorescence may be autofluorescence.
The exciting light may be emitted from a GaN semiconductor laser.
In accordance with another aspect of the present invention, there is provided an apparatus for obtaining a fluorescence image comprising an exciting light projecting means for projecting exciting light onto a specimen such as an organic body, a fluorescence intensity measuring means for measuring an intensity in at least one wavelength range of fluorescence emitted from the specimen upon excitation by the exciting light, and an operational processing means for obtaining image data representing a fluorescence image of the specimen through an operation based on the intensity of the fluorescence, wherein the improvement comprises that
a determining means determines whether each of pixels forming the fluorescence image is adequate for said operation on the basis of the intensity of the fluorescence of each pixel, and said operational processing means carries out said operation on adequate pixels, which have been determined to be adequate for said operation, to obtain values for the adequate pixels and allots to inadequate pixels, which have been determined not to be adequate for said operation, values which will not visually adversely affect the part of the fluorescence image corresponding to the adequate pixels.
For example, the determining means may determine whether each of pixels is adequate for said operation by comparing the intensity of fluorescence for the pixel with the value of noise for the pixel which is generated by the fluorescence intensity measuring means itself and has been measured and stored in advance.
The apparatus may further comprise an image processing means and the image processing means may carry out the image processing only on the adequate pixels.
The specimen may be an organic body and the fluorescence may be autofluorescence.
The exciting light projecting means may comprise a GaN semiconductor laser as an exciting light source.
The apparatus may be, for instance, an endoscope.
The xe2x80x9cnoise for the pixel which is generated by the fluorescence intensity measuring means itselfxe2x80x9d means a part or the whole of noise generated by the fluorescence intensity measuring means between the time the fluorescence intensity measuring means starts to receive the fluorescence and the time it finishes obtaining intensities of the fluorescence in respective wavelength ranges, or noise containing therein a part or the whole of such noise. Typical components of the noise generated by the fluorescence intensity measuring means include noises generated in the circuit of the image taking device, the circuit handling electric signals obtained by the image taking device, the signal transfer circuit for transferring the signals, and the optical system for taking the fluorescence.
When the fluorescence intensity measuring measures an intensity of the fluorescence in only one wavelength range, and the operational processing means obtains image data representing a fluorescence image of the specimen through an operation based on the intensity of the fluorescence in the wavelength range, the operation includes, for instance, an operation for allotting to pixels values reflecting the intensity of the fluorescence and an operation carried out between the intensity of the fluorescence in the wavelength range and a reference intensity obtained from light reflected by the specimen when a near infrared ray is projected onto the specimen. When the fluorescence intensity measuring measures intensities of the fluorescence in two or more wavelength ranges, and the operational processing means obtains image data representing a fluorescence image of the specimen through an operation based on the intensities of the fluorescence in the wavelength ranges, the operation includes, for instance, an operation carried out between the intensities of the fluorescence and an operation carried out among the intensities of the fluorescence in the wavelength ranges and a reference intensity obtained from light reflected by the specimen when a near infrared ray is projected onto the specimen.
When the amount of fluorescence received by a pixel is very small and accordingly the amount of noise included in the value for the pixel is too large relative to the amount of the fluorescence for the operation to provide a value which correctly reflects the condition of the specimen, the pixel is determined to be an inadequate pixel.
On the other hand, when the amount of fluorescence received by a pixel is large and accordingly the amount of noise included in the value for the pixel is relatively small so that the operation can provide a value which correctly reflects the condition of the specimen, the pixel is determined to be an adequate pixel.
The adequate and inadequate pixels do not exist from the beginning but are set on the basis of the amount of noise generated by the fluorescence intensity measuring means by itself and the measured amount of fluorescence.
Auto fluorescence emitted from the inside of an organic body is sometimes called xe2x80x9cin vivo autofluorescencexe2x80x9d.
In accordance with the present invention, since values which will not visually adversely affect the part of the fluorescence image corresponding to the adequate pixels are allotted to inadequate pixels, a fluorescence image which is free from adverse influence of inadequate pixels and is excellent in quality can be obtained.
Further, since the operation is carried out only on adequate pixels, the operation time can be shortened.
When whether each of pixels is adequate for said operation may be determined by comparing the intensity of fluorescence for the pixel with the value of noise for the pixel which is generated by means for measuring the intensity of fluorescence and has been measured and stored in advance, adequate pixels can be more rationally distinguished from inadequate pixels.
When image processing is carried out only on the adequate pixels, a fluorescence image which is free from adverse influence of inadequate pixels can be reproduced and the processing time can be shortened.
Use of a GaN semiconductor laser as the exciting light source contributes to miniaturization of the apparatus and reduction of the cost.
The method and apparatus of the present invention can be used to observe the condition of the inside of an organic body through autofluorescence emitted from the organic body upon excitation by the exciting light. That is, the present invention can be applied to an endoscope.

Method of and apparatus for obtaining fluorescence image


Photographic pyrazolotriazole dye forming coupler compounds of coupler intermediate compounds can be readily prepared in a single reaction medium by reacting certain pyrazolotriazole compounds with nitro-substituted aromatic compounds in the presence of a formate salt and a transition metal catalyst. This salt hydrogenates the nitro group and the carbonate by-product induces reaction of the resulting amine with the pyrazolotriazole compound. Yields and purity are high, and reaction time is reduced with the specific set of conditions and reactants, and environmental impact from waste is reduced. In addition, isolation of aromatic amine intermediates is avoided. The resulting pyrazolotriazole compounds can be used themselves as photographic dye forming couplers or further reacted to prepare useful coupler compounds for photographic use.

Color photographic silver halide materials are used to provide color images with the use of certain dye forming compounds that are usually in the various photosensitive silver halide layers of the materials. These dye forming compounds are conventionally known as "dye forming couplers" and are reactive with suitable oxidized forms of color developing agents used during photoprocessing to provide the desired dye images. Since most of such silver halide materials (such as color negative films and color papers) provide images based on what is known in the art as "subtractive color mixing", they typically include dye forming couplers that will provide cyan, yellow and magenta dyes in the appropriate photosensitive layers.
Pyrazolotriazoles have been known to be useful magenta dye forming couplers for some time, and various processes are known for preparing them, all of which usually include various chemical reactions taken in specific order. Such processes add functionality that defines the desired dye forming coupler early in the synthesis. These processes result in the lack of generality of the process and the need to make different intermediates for different dye forming coupler end products.
It is well known in the art [for example, U.S. Pat. No. 5,183,728 (Romanet et al), U.S. Pat. No. 5,457,210 (Kim et al) and U.S. Pat. No. 5,565,572 (Potenza et al)] that compounds defined by Formula IV below are known to be photographic dye forming couplers, as well as precursors to other photographic dye forming couplers.
It is known from EP 779,543 (Bose et al) that one common synthetic route to these types of compounds involves the high pressure catalytic reduction of a nitro aromatic compound (shown as Formula II below) using hydrogen to form an aromatic amine of Formula III, and then reaction of the aromatic amine with a compound of Formula IV under basic conditions. This is generally a two step process involving the isolation and handling of the aromatic amine of Formula III. ##STR1##
There are several disadvantages to such a two-step process. It includes increased cycle time due to increased handling requirements, increased air emissions if drying of the intermediate is required, and increased total volume of solvent needed. In addition, with this particular synthetic route, two different types of reaction vessels are needed. The catalytic hydrogenation of the first step requires specially designed high pressure equipment, while the displacement second reaction can be carried out in a standard reaction vessel. Additionally, this method requires the use of highly flammable hydrogen gas that presents a critical safety issue.
It is a desire in the industry to identify a chemical process that would transform aromatic nitro compounds of Formula II and the compounds of Formula IV into coupler precursors or couplers of Formula I in one step using one reaction vessel. It is also desired to accomplish this task with high chemical yield, high purity, short cycle time, low solvent usage, increased safety and minimal negative environmental impact.
One possible alternative to catalytic hydrogenation is a hydrogen transfer reaction [as described for example by Johnstone, et. al, Chem. Rev., 1985, 85, 129, Entistle, et. al, J. Chem. Soc., Perkin I, 1977, 443, and U.S. Pat. No. 5,041,605 (Huson et al)]. There are many possible hydrogen sources that can be used but each results in a different by-product.
Thus, there remains a need for an improved, single reaction medium synthesis of pyrazolotriazole dye forming coupler intermediates.

One-pot synthesis of pyrazolotriazole photographic dye forming color couplers and coupler intermediates


The present invention is directed to a display device which comprises two layers of insulating substrate, at least the substrate on the viewing side is transparent, an array of display cells sandwiched between the two layers of substrate, a writing means, and optionally an erasing means to magnetically or electrically erase the image. The display cells are filled with a dispersion of magnetic particles which may be charged or non-charged. The display of the invention eliminates the use of the transparent conductor film, such as ITO, on the viewing side. Therefore, the displays of this invention are more cost effective, more flexible and durable and capable of higher image contrast ratio and higher reflectance in the Dmin area.

An electrophoretic display (EPD) is a non-emissive device based on the electrophoresis phenomenon influencing charged pigment particles suspended in a colored dielectric solvent. This general type of display was first proposed in 1969. An EPD typically comprises a pair of opposed, spaced-apart plate-like electrodes, with spacers predetermining a certain distance between the electrodes. At least one of the electrodes, typically on the viewing side, is transparent.
When a voltage difference is imposed between the two electrodes, the pigment particles migrate by attraction to the plate of polarity opposite that of the pigment particles. Thus, the color showing at the transparent plate, determined by selectively charging the plates, can be either the color of the solvent or the color of the pigment particles. Reversal of plate polarity will cause the particles to migrate back to the opposite plate, thereby reversing the color. Intermediate color density (or shades of gray) due to intermediate pigment density at the transparent plate may be obtained by controlling the plate charge through a range of voltages or pulsing time.
EPDs of different pixel or cell structures have been reported previously, for example, the partition-type EPD (M. A. Hopper and V. Novotny, IEEE Trans. Electr. Dev., 26(8):1148–1152 (1979)) and the microencapsulated EPD (U.S. Pat. Nos. 5,961,804 and 5,930,026).
An improved EPD technology was disclosed in co-pending applications, U.S. Ser. No. 09/518,488, filed on Mar. 3, 2000 (corresponding to WO 01/67170 published on Sep. 13, 2001), U.S. Ser. No. 09/606,654, filed on Jun. 28, 2000 (corresponding to WO 02/65215 published on Aug. 22, 2002) and U.S. Ser. No. 09/784,972, filed on Feb. 15, 2001 (corresponding to WO 02/01281 published on Jan. 3, 2002), all of which are incorporated herein by reference. The improved EPD comprises isolated cells formed from microcups of well-defined shape, size and aspect ratio and filled with charged particles dispersed in a dielectric solvent or solvent mixture, preferably a halogenated solvent, particularly a perfluorinated solvent. The filled cells are individually sealed with a polymeric sealing layer, preferably formed from a composition comprising a material selected from a group consisting of thermoplastics, thermosets and precursors thereof.
All of the previously known and the microcup-based electrophoretic displays may be constructed into the form of a board to be used as e-signs or e-bulletins. However, the use of a transparent conductor film, such as indium tin oxide (ITO) on the viewing side, particularly the patterned film, in these large displays is an economic disadvantage as the transparent conductor film is expensive. The expense for the transparent conductor film often is a major part of the total manufacturing cost of the electrophoretic display. In addition, the ITO film is brittle and only provides about 80–90% of transmission or reflection in the visible light region. Therefore, there is still a need for a solution to these issues.

This patent is subject to a terminal disclaimer.

Magnetophoretic and electromagnetophoretic displays


Method and apparatus for enhancing the ability of a subscriber to connect to a carrier network by enabling the service provider to indicate to the subscriber when a requested connection to the carrier network would utilize unguaranteed bandwidth and, absent objection by the subscriber, to complete the requested connection utilizing the unguaranteed bandwidth. Upon receipt of a request for set-up of a call of an indicated bandwidth, the service provider will acknowledge the call set-up request. The service provider will then issue a call proceeding message to indicate that the requested connection is being arranged. The call proceeding message will contain an unguaranteed bandwidth indicator if the carrier network cannot guarantee the requested bandwidth. If a cancellation of the call request is not received in response to the unguaranteed bandwidth indicator, the call will be completed.

Generally speaking, bandwidth is the range of frequencies that a communications system, for example, a carrier network, is capable of carrying along its transmission medium. As each communication channel provided by the carrier network consumes a portion of the network's bandwidth, the bandwidth of the carrier network limits the number of communication channels which it can provide to its subscribers.
Different types of communications require different bandwidths. For example, one video channel requires approximately the same bandwidth as 1,200 voice telephone channels. In order to provide a single system capable of carrying the various types of communications, carrier networks are gradually evolving towards architectures such as asynchronous transfer mode (or "ATM") which will provide variable bandwidth to subscribers. It is contemplated that such networks will be particularly well suited for transmission of various types of media--voice, data, image and video--each requiring a different amount of bandwidth to complete the transmission.
An important concept in ATM is Quality of Service (or "QoS"). QoS defines the standards to which an ATM provider will adhere to when providing service to a subscriber. Based upon its planned usage of the ATM network, a subscriber will enter into a traffic contract with a service provider for a specific amount of bandwidth. Among other things, QoS assures the subscriber that the contracted bandwidth will be available for data transfers at a specified bit rate. Due to the increased cost thereof, a subscriber will rarely contract for bandwidth in excess of their expected usage. Problems may arise, however, if the subscriber attempts to complete a call or other type of connection which, if completed, would result in the subscriber consuming bandwidth in excess of the amount to which he or she had previously contracted for. For example, a subscriber may contract for sufficient bandwidth to complete a single voice channel but then attempt to conduct a video conference. Most service providers do not permit the subscriber to consume excess bandwidth and would, therefore, reject any requested connection which would produce such a result. Such rejections are often based upon the fear that, if the request were accepted, the service provider would not be able to maintain the specified data rate for the connection, thereby resulting in the loss of one or more data calls.

Method and apparatus for providing subscribers with unguaranteed bandwidth connections wherein subscribers are alerted by encoded messages or a warning tone


There is described a prosthetic valve to be inserted into a body lumen, the valve having leaflets that are spread apart during forward flow of fluid to create an orifice, and the leaflets coming into contact with each other during reverse flow of fluid, thereby impeding the reverse flow of fluid, the valve comprising: a hollow, cylindrical stent having an inner surface and an outer surface, and having a first and a second open end; and valve means formed from a single tubular membrane, the membrane mounted to the stent, the membrane having a graft portion internally folded and bonded to itself at a plurality of points to form pouches such that the leaflets extend from the pouches, and a sleeve portion on an outer surface of the stent to secure the membrane thereto.

The primary function of a valve is to ensure that a fluid flows only in one direction. There are many valves in the human body, helping to make sure that homeostasis is maintained in an efficient manner. There are four valves in the heart that regulate the direction and flow of blood. The pulmonary valve directs blood from the right ventricle into the main pulmonary artery where it flows into the lungs. The aortic valve directs blood towards the aorta, the main artery of the body. The mitral and tricuspid valves are internal to the heart, directing blood flow between the atria and ventricles. Valves may fail to function due to inadequate opening (also known as narrowing, or stenosis), inadequate closure (also known as leaking, or regurgitation or insufficiency), or a combination of both processes. The aortic valve is the one that most commonly fails in older adults. In children, the pulmonary and aortic valves are the ones that most often need to be repaired or replaced due to congenital defects.
Pulmonary insufficiency (regurgitation) can be a result of congenital heart disease. Typically this condition would be exhibited by patients who have had previous repair of Tetralogy of Fallot. Another indication would be insufficiency of a right ventricle-to-pulmonary artery conduit, also seen in Tetralogy of Fallot or pulmonary atresia with ventricular septal defect (VSD), and also after previous repair of truncus arteriosus.
The traditional way to replace cardiac valves in patients involves open-heart surgery. The patient must be placed under general anesthesia for several hours. The patient's sternum is cut open, and incisions are made through the various tissue layers and into the heart to expose the area of interest. A replacement valve is implanted. A cardiac bypass machine must be used to pump blood while the heart is stopped. This type of surgery causes significant trauma to the patient with prolonged healing times.
The replacement heart valves currently available for traditional open-heart surgery have both advantages and disadvantages. Mechanical valves are long lasting and durable, but may require a lifetime of anticoagulation (anti-clotting) treatment. The mechanism of closure may damage blood cells and platelets, as well, it may be audible to the patient. Biological valves, usually harvested from pigs or cows (eg. Bovine jugular veins), do not generally last as long as mechanical valves, as they tend to calcify and stiffen. Their advantage is that they do not require that patients take anticoagulation treatment. As well, with growing concerns over the possible spread of disease from animal tissues (eg. Mad cow disease), it would be ideal to avoid the biological tissues altogether. Children with congenital heart disease may require several operations over a period of years to correct multiple cardiac defects. Repeated surgical repair or replacement of cardiac valves places an additional burden on them.
A biological valve for surgical implantation is sometimes mounted into a support structure called a stent. This stent is a supportive material that is surgically sutured into the valve. A biological valve supported by a stent that is inserted surgically can be referred to as a stented valve. Biological valves can be stented valves or unstented valves.
The rapidly developing specializations of interventional cardiology and interventional radiology involve placing tools and devices deep into the body under imaging guidance through small incisions percutaneously("through the skin") into veins or arteries. These procedures are less invasive than traditional open-heart surgery, allowing the patient to recover more quickly. The procedures take less time to perform, are safer, and are generally less costly. Percutaneous technologies therefore benefit both the patients and the health care system.
Due to the benefits of percutaneous procedures over open surgery, there has been increasing interest in developing percutaneous methods of replacing heart valves. Prior art systems include valves that can be delivered and deployed percutaneously. Progress has been made with the designs, however none of the designs are ideal, each having important limitations.
Bonhoeffer is a researcher that has performed clinical trials on animals and humans. A pulmonary valve has been percutaneously implanted in several patients. The valve is composed of an 18 mm bovine internal jugular vein with a native valve that has been dissected and reduced in profile. The valve is mounted on an expandable stent, and loaded into a specially made 18 F sheath. The system is delivered over a guide-wire and deployed using an expandable balloon. This research has been documented in several scientific papers. The valve and stent are disclosed in European Patent Application No. 1057460.
There are many disadvantages to the Bonhoeffer valve. The main one is that a large sheath is required (18-22 F) for implantation of the valve, too large to be used in small children. Bonhoeffer employs biological material as his choice for the valve. Biological materials are known to have less durability. Biological valves experiences calcification after a relatively short time period and cease to function adequately. In addition, obtaining biological material and forming it into a valve is difficult and time consuming. The biological material must be treated chemically, in effort to improve longevity and to reduce the risk of disease transmission.
Cribier is another researcher, focusing on the percutaneous implantation of aortic valves in adults. The Cribier valve that has been used in patient trials was made of either bovine pericardium or equine pericardium. The stent was 14 mm in length, and was delivered on a balloon 30 mm in length with a maximal diameter of 23 mm. The delivery profile for the assembly is even larger than that of Bonhoeffer's at 24 F.
U.S. patent application Ser. No. 2003/0023300, World Patent Application No. 02/47575, and U.S. Pat. Nos. 6,440,164 and 6,503,272 all disclose a percutaneously delivered non-biological valve mounted on a stent, which can also be referred to as a valve-stent. A main disadvantage of these designs is that the valve leaflets are supported by metal that is either an extension of the stent, or welded to it. The metal is expected to move into different positions, thereby opening and closing the orifice with each heartbeat. This will place considerable stress on the joint, potentially causing early failure of the valve due to metal fatigue.
Biological valves harvested from animals have benefits, and are therefore selected for many designs in the prior art. However, there are also many disadvantages to their use. Biological valves calcify and stiffen, which leads to deterioration in valve function over time. They require a large sheath size for introduction into the body, increasing the risk of vessel trauma in adults, and excluding their use in children. Finally, biological valves are difficult to work with. Each valve involves the slaughter of an animal, then a manual harvesting of the valve, careful chemical treatment, and hand assembly of the valve. The process is cumbersome, and labor intensive. U.S. Pat. Nos. 6,582,462, 6,425,916, 5,957,949 and World Patent Application No. 0047136A1 all disclose a biological valve as a preferred embodiment and suffer from the described disadvantages.
A healthy heart of an average human beats about 70 times a minute. This translates into approximately 600 million beats over a 15 year period, which is the FDA requirement for a mechanical heart valve. The FDA requirement for a biological heart valve is that it must last 5 years, or 200 million beats. Therefore, a heart valve must be designed and engineered to be rugged and durable. A general engineering principle is that simpler designs last longer, the smaller the number of components and parts, the lower the probability of component failure. Therefore, in designing a heart valve, the number of different materials, sutures and bonds should be minimized. United States Patent Application No. 20020198594A1 and World Patent Application No. 03047468A1 involve complex designs, with a large number of sutures and bonds, as well as different materials for the leaflets and stent graft.
U.S. Pat. No. 6,287,334 discloses a valve made out of synthetic bioprosthetic material. Three cone shaped cavities open and close with regards to the pressure differential of the fluid, thereby creating an opening in one direction, and closing in the other. This design features three independent cones, increasing the likelihood of valve dysfunction if one of the cones does not open in response to a change in pressure. This may occur if the material sticks to itself because of the adhesive attraction property of water. A second drawback to this design is that a cone is not a natural shape for a valve. Blood may pool at the bottom of the cone, stagnate, and form clots.
United States Patent Application No. 20030130729 seeks to solve the above problems by using only a biological material, and folding it in such a way as to create leaflets. The rectangular piece of biological material needs to be treated in a certain manner, dehydrated, folded and re-hydrated to achieve the desired result. The end result of the folding should be leaflets inside of a tube that is bonded or sutured to the stent. A problem with this design is that a suture line is created, where the two edges are connected to form a tube. This suture line interferes with the operation of the leaflets. It also acts as an opening for blood to seep into the space between the graft and artery, increasing the risk of clot formation.
U.S. Pat. No. 5,855,601 discusses a valve mounted on a stent, in which the leaflets and graft are formed from a single piece of material. Another embodiment is for the cusp to be secured to the outer side of the stent. If the first embodiment is selected, the leaflets may stick to the graft if both are made out of a synthetic plastic-like material. If the second embodiment is selected, then the leaflets on the inside will rub against the metal of the stent, thereby wearing out faster and reducing the life of the valve. In both embodiments, no mechanism is described for preventing the leaflets from inverting instead of closing with an alternating pressure differential. An inversion of leaflets is a hazardous situation, rendering the valve non-functional, and causing severe insufficiency.
United States Patent Application No. 20030109924 also seeks to solve the above problems, by using a continuous material to form a valvular structure that can deform to block the flow of fluid. The valvular structure collapses the same way each time along stiffened zones. The shape of the material is a truncated hyperboloid shape, the base is large, and ends in a smaller neck. A disadvantage of this design is that the orifice area is reduced. In fact, this patent acknowledges the smaller orifice area, and admits that this invention can only be used in elderly patients, as their cardiac output is lower.


A slide rail assembly includes a slide assembly, a front support, a first rear support, a second rear support, and a reinforcement member. The slide rail assembly includes an outer rail, an inner rail and an intermediate rail. The front support and the first rear support are respectively connected to the front end and the outside of the outer rail. The second rear support is movably connected to the first rear support. The reinforcement member includes a body, two first support parts and at least two second support parts. The body has a slot and a contact portion. The two first support parts embrace the outer rail, and the at least two second support parts embrace the second rear support. The slide rail assembly is installed to the rack. The reinforcement member reinforces the connection between the second rear support and the outer rail.

U.S. Pat. No. 8,028,965 to CHEN discloses an adjustable bracket for a slide assembly which can be installed to different depths of the racks. The amount of the adjustment of the bracket is made by the relative displacement between the cover (30) and the rear support (50). When the rear support is completely retracted to the cover, the total length of the bracket reaches its minimum length. When the rear support is pulled, relative to the cover, to its extreme position, the total length of the bracket reaches its maximum length. However, when the rear support is pulled to its extreme position, the rear support must be partially inserted into the cover so as to maintain the support strength. Accordingly, the length that the rear support inserted in the cover cannot be too short. If the total length of the bracket is to be increased, the length that the rear support is pulled relative to the cover cannot be overly increased so as to maintain a minimum support strength. Consequently, to increase the total length of the bracket, only the two respective lengths of the cover or the rear support can be increased. However, once the length of one of the cover or the rear support is increased, the minimum length of the bracket is increased and cannot meet the original requirement of the minimum length of the support.
The present invention intends to provide a slide rail assembly with a reinforcement member which is adjustable to meet requirements of maximum or minimum and to reinforce the structural strength thereof.

Slide rail assembly for use in rack system and reinforcement member thereof


A method of integrating a first substrate having a first surface with a first insulating material and a first contact structure with a second substrate having a second surface with a second insulating material and a second contact structure. The first insulating material is directly bonded to the second insulating material. A portion of the first substrate is removed to leave a remaining portion. A third substrate having a coefficient of thermal expansion (CTE) substantially the same as a CTE of the first substrate is bonded to the remaining portion. The bonded substrates are heated to facilitate electrical contact between the first and second contact structures. The third substrate is removed after heating to provided a bonded structure with reliable electrical contacts.

1. Field of the Invention
The present invention relates to the field of three-dimensional integrated circuits and more particularly to devices and the fabrication thereof of three-dimensional integrated circuits using direct wafer bonding.
2. Description of the Related Art
Semiconductor integrated circuits (ICs) are typically fabricated into and on the surface of a silicon wafer resulting in an IC area that must increase as the size of the IC increases. Continual improvement in reducing the size of transistors in ICs, commonly referred to as Moore's Law, has allowed a substantial increase in the number of transistors in a given IC area. However, in spite of this increased transistor density, many applications require an increase in total IC area due to a greater increase in required transistor count or an increase in the number of lateral interconnections required between transistors to achieve a specific function. The realization of these applications in a single, large area IC die typically results in a reduction in chip yield and, correspondingly, increased IC cost.
Another trend in IC fabrication has been to increase the number of different types of circuits within a single IC, more commonly referred to as a System-on a-Chip (SoC). This fabrication typically requires an increase in the number of mask levels to make the different types of circuits. This increase in mask levels typically also results in a reduction in yield, and correspondingly, increased IC cost. A solution to avoiding these undesired decreases in yield and increases in cost is to vertically stack and vertically interconnect ICs. These ICs can be of different size, come from different size wafers, comprise different functions (i.e., analog, digital, optical), be made of different materials (i.e., silicon, GaAs, InP, etc.). The ICs can be tested before stacking to allow Known Good Die (KGD) to be combined to improve yield. The economic success of this vertical stacking and vertical interconnect, or three-dimensional 3D SoC, approach depends on the yield and cost of the stacking and interconnection being favorable compared to the yield and cost associated with the increased IC or SoC area. A manufacturable method for realizing this approach is to vertically stack separately fabricated ICs using direct bonding where the direct bonding surface preparation uses conventional wafer fabrication techniques, for example, metal deposition, dielectric deposition, chemo-mechanical polishing, wafer thinning, photolithography masking, and via etching. A further advantage of using direct bonding for 3D SoC fabrication is the ability to achieve a scalable density of vertical interconnections between different layers or tiers of the stack as a result of the direct bond process.
Direct bonding requires a substantially planar surface that does not result from typical IC wafer fabrication. Achieving an adequate wafer planarization can thus be a substantial element of cost in a direct bond process. It is thus desirable to have a device that comprises a structure and a method to fabricate said structure requiring a minimum cost to achieve this required surface planarity.
Metal direct bonding includes methods and devices for forming 3D structures wherein electrically isolated electrical interconnections can be made across a bond interface which can be formed by aligning and placing two surfaces of two elements into direct contact. Each surface can have insulating and conducting portions and aligned conducting portions can result in a 3D electrical interconnection across the bond interface, and aligned insulating portions can isolate 3D electrical interconnections from other 3D electrical interconnections.
The details of making of a 3D electrical interconnections across the bond interface depends on the relative planarity of the insulating and conducting portions. For example, if the conducting portions are higher than the insulating portions, a 3D interconnection can be made by simply placing two surfaces into contact, for example if the there is not a native oxide on the conducting portion preventing a 3D interconnection and the extension of the conducting portion above the insulating portion is sufficiently small that insulating portions can also bond in direct contact with surface compliance. 3D interconnections may also not be made by simply placing two surfaces into contact, for example if the conducting portions are lower than the insulating portions such that the conducting portions do not come into contact when the surfaces are place together. In this example, 3D interconnections can be made with a slight increase in temperature due to the coefficient of thermal expansion (CTE) difference between the conducting and insulating portion and an adequate bond energy between insulating components that sufficiently compresses the conducting components during heating if the elements are of standard thickness. If the CTE of the elements are comparable, the slight increase in temperature to make a connection can be accommodated by the bond energy of the insulating portions that are in contact and the stiffness of the element. If the CTE of the elements are not comparable, for example for some heterogeneous material combinations, high bond energy of the insulating portions in contact can result in fracture of one or both of the elements during the heating used to make the 3D interconnections. This fracture can be avoided by thinning one of the elements sufficiently prior to heating. This thinning increases the compliance of the element by reducing its stiffness so that it can accommodate the CTE difference of the elements. Thinning to accommodate this difference in CTE can result in a reduced stiffness of the element such that compression is not adequate to make a 3D interconnection.

Heterogeneous annealing method and device


A method includes acquiring a media content directory on at least one media server, and identifying media description information in at least two media resource objects in the media content directory and integrating the at least two media resource objects when media resources respectively corresponding to the at least two media resource objects have same media content, so the integrated at least two media resource objects are represented by one media identifier. The method also includes sending, according to capability information of a media playback device selected by a user, a media resource address corresponding to a first media resource object to the media playback device, so the media playback device acquires and plays a media resource corresponding to the media resource address, where the first media resource object is one of the at least two media resource objects that are suitable to be played on the media playback device.

With development of digital home technologies and widespread digitalization of consumer electronics, digitalized entertainment devices and home appliance products are increasingly occurring in families, and also become increasingly rich in variety, and media format types suitable to be used by various devices are also diverse.
Differences exist between device capabilities and supported media format models of various products in a home area network; therefore, some media files cannot be played on all playback devices, and a series of problems in an aspect of media interoperations is caused. Generally, one original media file is extended, by transcoding or in a manner of downloading from different content providers, to obtain multiple media files that have different media formats and/or resolution but represent same content, so that the media content can be played on different media playback devices in the home area network.
In an existing technical solution, discrete media content directories that are obtained by transcoding or downloading and stored on media servers are aggregated and integrated into one total content directory. For media files that have different media formats but same content, a problem of how to perform integration processing on the media files that have same media content is not considered. Therefore, although the content directories are aggregated into one content directory, multiple media files whose titles are the same or similar may occur in the content directory.


A method and apparatus for measuring a volume of a wound are described, the method comprising the steps of: applying a dressing over a wound, the volume of which is to be measured, the dressing including at least a sealing drape over the wound so as to create a sealed wound cavity; creating a vacuum in said wound cavity by vacuum pump means so as to produce a predetermined vacuum in the wound cavity; measuring a volume of air extracted from said wound cavity in producing said predetermined vacuum; and, calculating a volume of said wound.

1. Field
The present invention relates to apparatus and a method for the measurement of wound volume to assess progress of wound healing particularly, though not exclusively, during topical negative pressure (TNP) therapy.
2. Background
There is much prior art available relating to the provision of apparatus and methods of use thereof for the application of TNP therapy to wounds together with other therapeutic processes intended to enhance the effects of the TNP therapy. Examples of such prior art include those listed and briefly described below.
TNP therapy assists in the closure and healing of wounds by reducing tissue oedema; encouraging blood flow and granulation of tissue; removing excess exudates and may reduce bacterial load and thus, infection to the wound. Furthermore, TNP therapy permits less outside disturbance of the wound and promotes more rapid healing.
In our co-pending International patent application, WO 2004/037334, apparatus, a wound dressing and a method for aspirating, irrigating and cleansing wounds are described. In very general terms, this invention describes the treatment of a wound by the application of topical negative pressure (TNP) therapy for aspirating the wound together with the further provision of additional fluid for irrigating and/or cleansing the wound, which fluid, comprising both wound exudates and irrigation fluid, is then drawn off by the aspiration means and circulated through means for separating the beneficial materials therein from deleterious materials. The materials which are beneficial to wound healing are recirculated through the wound dressing and those materials deleterious to wound healing are discarded to a waste collection bag or vessel.
In our co-pending International patent application, WO 2005/04670, apparatus, a wound dressing and a method for cleansing a wound using aspiration, irrigation and cleansing wounds are described. Again, in very general terms, the invention described in this document utilises similar apparatus to that in WO 2004/037334 with regard to the aspiration, irrigation and cleansing of the wound, however, it further includes the important additional step of providing heating means to control the temperature of that beneficial material being returned to the wound site/dressing so that it is at an optimum temperature, for example, to have the most efficacious therapeutic effect on the wound.
In our co-pending International patent application, WO 2005/105180, apparatus and a method for the aspiration, irrigation and/or cleansing of wounds are described. Again, in very general terms, this document describes similar apparatus to the two previously mentioned documents hereinabove but with the additional step of providing means for the supply and application of physiologically active agents to the wound site/dressing to promote wound healing.
The content of the above references is included herein by reference.
However, the above apparatus and methods are generally only applicable to a patient when hospitalised as the apparatus is complex, needing people having specialist knowledge in how to operate and maintain the apparatus, and also relatively heavy and bulky, not being adapted for easy mobility outside of a hospital environment by a patient, for example.
Some patients having relatively less severe wounds which do not require continuous hospitalisation, for example, but whom nevertheless would benefit from the prolonged application of TNP therapy, could be treated at home or at work subject to the availability of an easily portable and maintainable TNP therapy apparatus.
One particular area of wound therapy which is desirable is to monitor the volume of a wound during its treatment such as, for example, at dressing change time so as to be able to quantify the healing process. However, there are presently no simple and/or accurate tools with which to make this assessment of wound volume.
Methods which have been used have include measuring the length, width and depth of a wound and making some assessment from the dimensions but this is very inaccurate; Taking a tracing around the wound, calculating the area and taking depth measurements; filling the wound with a filler and measuring the wound volume based on a known density of the filler; and photographic methods. All of these prior methods involve making calculated guesses resulting in inaccurate volume figures or are time consuming or are rather impractical.
Desirably, wound volume should be measured when a dressing is changed at, for example, every few days so as to keep a continuous record of progress.
Whatever method was used it would result in the figures having to be stored in a file, for example, and generally not with the patient being treated.

Apparatus and method for wound volume measurement


An N.sup.th order delayed extraction apparatus and method for use in a time-of-flight mass spectrometer is disclosed. A non-linear electric field, produced by specially formed electrodes, is used to accelerate ions, improve flight time focusing and thereby increase mass resolution.

Mass spectrometry (MS) has long been used to provide both quantitative and qualitative data not easily available from other analytical techniques. The broad scope of MS technology has been used to provide molecular weight, empirical formula, isotope ratios, identification of functional groups, and elucidation of structure. A great deal of research has been expended in further developing mass spectrometry technology, and improvements in this technology offer realistic expectations of substantially increased use of this analytical procedure.
This invention relates in general to ion beam handling in mass spectrometers and more particularly to a means of accelerating ions in time-of-flight mass spectrometers (TOFMS).
The apparatus and method of mass analysis described herein is an enhancement of the techniques that are referred to in the literature relating to mass spectrometry.
Mass spectrometers are instruments that are typically used to determine the chemical structures of molecules. In operation, molecules become positively or negatively charged in an ionization source and the masses of the resultant ions are determined in vacuum by a mass analyzer that measures their mass/charge (m/z) ratio. Mass analyzers come in a variety of types, including magnetic field (B), combined (double-focusing) electrical (E) and magnetic field (B), quadrupole (Q), ion cyclotron resonance (ICR), quadrupole ion storage trap, and time-of-flight (TOF) mass analyzers, which are of particular importance with respect to the invention disclosed herein. Each mass spectrometric method has a unique set of attributes. Thus, TOFMS is one mass spectrometric method that arose out of the evolution of the larger field of mass spectrometry.
The analysis of ions by TOFMS is, as the name suggests, based on the measurement of the flight times of ions from an initial position to a final position. Ions which have the same initial kinetic energy but different masses will separate when allowed to drift through a field free region.
Ions are conventionally extracted from an ion source in small packets. The ions acquire different velocities according to the mass-to-charge ratio of the ions. Lighter ions will arrive at a detector prior to high mass ions. Determining the time-of-flight of the ions across a propagation path permits the determination of the masses of different ions. The propagation path may be circular or helical, as in cyclotron resonance spectrometry, but typically linear propagation paths are used for TOFMS applications.
TOFMS is used to form a mass spectrum for ions contained in a sample of interest. Conventionally, the sample is divided into packets of ions that are launched along the propagation path using a pulse-and-wait approach. In releasing packets, one concern is that the lighter and faster ions of a trailing packet will pass the heavier and slower ions of a preceding packet. Using the traditional pulse-and-wait approach, the release of an ion packet as timed to ensure that the ions of a preceding packet reach the detector before any overlap can occur. Thus, the periods between packets is relatively long. If ions are being generated continuously, only a small percentage of the ions undergo detection. A significant amount of sample material is thereby wasted. The loss in efficiency and sensitivity can be reduced by storing ions that are generated between the launching of individual packets, but the storage approach carries some disadvantages.
Resolution is an important consideration in the design and operation of a mass spectrometer for ion analysis. The traditional pulse-and-wait approach in releasing packets of ions enables resolution of ions of different masses by separating the ions into discernible groups. However, other factors are also involved in determining the resolution of a mass spectrometry system. "Space resolution" is the ability of the system to resolve ions of different masses despite an initial spatial position distribution within an ion source from which the packets are extracted. Differences in starting position will affect the time required for traversing a propagation path. "Energy resolution" is the ability of the system to resolve ions of different mass despite an initial velocity distribution. Different starting velocities will affect the time required for traversing the propagation path.
In addition, two or more mass analyzers may be combined in a single instrument to form a tandem mass spectrometer (MS/MS, MS/MS/MS, etc.). The most common MS/MS instruments are four sector instruments (EBEB or BEEB), triple quadrupoles (QQQ), and hybrid instruments (EBQQ or BEQQ). The mass/charge ratio measured for a molecular ion is used to determine the molecular weight of a compound. In addition, molecular ions may dissociate at specific chemical bonds to form fragment ions. Mass/charge ratios of these fragment ions are used to elucidate the chemical structure of the molecule. Tandem mass spectrometers have a particular advantage for structural analysis in that the first mass analyzer (MS1) can be used to measure and select molecular ion from a mixture of molecules, while the second mass analyzer (MS2) can be used to record the structural fragments. In tandem instruments, a means is provided to induce fragmentation in the region between the two mass analyzers. The most common method employs a collision chamber filled with an inert gas, and is known as collision induced dissociation ("CID"). Such collisions can be carried out at high (5-10 keV) or low (10-100 eV) kinetic energies, or may involve specific chemical (ion-molecule) reactions. Fragmentation may also be induced using laser beams (photodissociation), electron beams (electron induced dissociation), or through collisions with surfaces (surface induced dissociation). It is possible to perform such an analysis using a variety of types of mass analyzers including TOF mass analysis.
In a TOFMS instrument, molecular and fragment ions formed in the source are accelerated to a kinetic energy: ##EQU1## where e is the elemental charge, V is the potential across the source/accelerating region, m is the ion mass, and v is the ion velocity. These ions pass through a field-free drift region of length L with velocities given by equation 1. The time required for a particular ion to traverse the drift region is directly proportional to the square root of the mass/charge ratio: ##EQU2## Conversely, the mass/charge ratios of ions can be determined from their flight times according to the equation: ##EQU3## where a and b are constants which can be determined experimentally from the flight times of two or more ions of known mass/charge ratios.
Generally, TOF mass spectrometers have limited mass resolution. This arises because there may be uncertainties in the time that the ions were formed (time distribution), in their location in the accelerating field at the time they were formed (spatial distribution), and in their initial kinetic energy distributions prior to acceleration (energy distribution).
The first commercially successful TOFMS was based on an instrument described by Wiley and McLaren in 1955 (Wiley, W. C.; McLaren, I. H., Rev. Sci. Instrumen. 26 1150 (1955)). That instrument utilized electron impact (EI) ionization (which is limited to volatile samples) and a method for spatial and energy focusing known as time-lag focusing. In brief, molecules are first ionized by a pulsed (1-5 microsecond) electron beam. Spatial focusing was accomplished using multiple-stage acceleration of the ions. In the first stage, a low voltage (-150 V) drawout pulse is applied to the source region that compensates for ions formed at different locations, while the second (and other) stages complete the acceleration of the ions to their final kinetic energy (-3 keV ). A short time-delay (1-7 microseconds) between the ionization and drawout pulses compensates for different initial kinetic energies of the ions, and is designed to improve mass resolution. Because this method required a very fast (40 ns) rise time pulse in the source region, it was convenient to place the ion source at ground potential, while the drift region floats at -3 kV. The instrument was commercialized by Bendix Corporation as the model NA-2, and later by CVC Products (Rochester, N.Y.) as the model CVC-2000 mass spectrometer. The instrument has a practical mass range of 400 daltons and a mass resolution of 1/300, and is still commercially available.
There have been a number of variations on this instrument. Muga (TOFTEC, Gainsville) has described a velocity compaction technique for improving the mass resolution (Muga velocity compaction). Chatfield et al. (Chatfield FT-TOF) described a method for frequency modulation of gates placed at either end of the flight tube, and Fourier transformation to the time domain to obtain mass spectra. This method was designed to improve the duty cycle.
Cotter et al. (VanBreeman, R. B.: Snow, M.: Cotter, R. J., Int. J. Mass Spectrom. Ion Phys. 49 (1983) 35.; Tabet, J. C.; Cotter, R. J., Anal. Chem. 56 (1984) 1662; Olthoff, J. K.; Lys, I.: Demirev, P.: Cotter, R. J., Anal. Instrumen. 16 (1987) 93, modified a CVC 2000 time-of-flight mass spectrometer for infrared laser desorption of involatile biomolecules, using a Tachisto (Needham, Mass.) model 215G pulsed carbon dioxide laser. This group also constructed a pulsed liquid secondary time-of-flight mass spectrometer (liquid SIMS-TOF) utilizing a pulsed (1-5 microsecond) beam of 5 keV cesium ions, a liquid sample matrix, a symmetric push/pull arrangement for pulsed ion extraction (Olthoff, J. K.; Cotter, R. J., Anal. Chem. 59 (1987) 999-1002.; Olthoff, J. K.; Cotter, R. J., Nucl. Instrum. Meth. Phys. Res. B-26 (1987) 566-570. In both of these instruments, the time delay range between ion formation and extraction was extended to 5-50 microseconds, and was used to permit metastable fragmentation of large molecules prior to extraction from the source. This in turn reveals more structural information in the mass spectra.
The plasma desorption technique introduced by Macfarlane and Torgerson in 1974 (Macfarlane, R. D.; Skowronski, R. P.; Torgerson, D. F., Biochem. Biophys. Res Commoun. 60 (1974) 616.) formed ions on a planar surface placed at a voltage of 20 kV. Since there are no spatial uncertainties, ions are accelerated promptly to their final kinetic energies toward a parallel, grounded extraction grid, and then travel through a grounded drift region. High voltages are used, since mass resolution is proportional to UO/eV, where the initial kinetic energy, UO is of the order of a few electron volts. Plasma desorption mass spectrometers have been constructed at Rockefeller (Chait, B. T.; Field, F. H., J. Amer. Chem. Soc. 106 (1984) 193), Orsay (LeBeyec, Y.; Della Negra, S.; Deprun, C.; Vigny, P.; Giont, Y. M., Rev. Phys. Appl 15 (1980) 1631), Paris (Viari, A.; Ballini, J. P.; Vigny, P.; Shire, D.; Dousset, P., Biomed. Environ. Mass Spectrom, 14 (1987) 83), Upsalla (Hakansson, P.; Sundqvist B., Radiat. Eff. 61 (1982) 179) and Darmstadt (Becker, O.; Furstenau, N.; Krueger, F. R.; Weiss, G.; Wein, K., Nucl. Instrum. Methods 139 (1976) 195). A plasma desorption time-of-flight mass spectrometer has been commercialized by BIO-ION Nordic (Upsalla, Sweden). Plasma desorption utilizes primary ion particles with kinetic energies in the MeV range to induce desorption/ionization. A similar instrument was constructed at Manitoba (Chain, B. T.; Standing, K. G., Int. J. Mass Spectrum. Ion Phys. 40 (1981) 185) using primary ions in the keV range, but has not been commercialized.
Matrix-assited laser desorption, introduced by Tanaka et al. (Tanaka, K.; Waki, H.; Ido, Y.; Akita, S.; Yoshida, Y.; Yoshica, T., Rapid Commun. Mass Spectrom. 2 (1988) 151) and by Karas and Hillenkamp (Karas, M.; Hillenkamp, F., Anal. Chem. 60 (1988) 2299) utilizes TOFMS to measure the molecular weights of proteins in excess of 100,000 daltons. An instrument constructed at Rockefeller (Beavis, R. C.; Chait, B. T., Rapid Commun. Mass Spectrom. 3 (1989) 233) has been commercialized by VESTEC (Houston, Tex.), and employs prompt two-stage extraction of ions to an energy of 30 keV.
Time-of-flight instruments with a constant extraction field have also been utilized with multi-photon ionization, using short pulse lasers.
The instruments described thus far are linear time-of-flights, that is: there is no additional focusing after the ions are accelerated and allowed to enter the drift region. Additional energy focusing approaches have also been developed, including passing the ion beam through an electrostatic energy filter.
Since at least the mid 1970's, it has also been known to use a mass reflectron in conjunction with mass spectrometry in order to improve performance. A mass reflectron for a time-of-flight mass spectrometer is disclosed in an article entitled "The Mass Reflectron, A New Nonmagnetic Time-of-Flight Mass Spectrometer with High Resolution" by Mamyrin et al. A mass spectrometer with an improved reflectron is discussed in an article by Gohl et al entitled "Time-of-Flight Mass Spectrometry for Ions of Large Energy Spread", with this latter reflectron utilizing a "two-stage mirror" to minimize ion flight time variations. A recent article entitled "A Secondary Ion Time-of-Flight Mass Spectrometer With an Ion Mirror" by Tang et al illustrated that the two-stage mirror concept does not provide substantially improved results over a single-stage mirror. Accordingly, much of the effort to improving mass spectrometry techniques has been directed away from improvements to the reflectron.
U.S. Pat. No. 4,778,993 is directed to time-of-flight (TOF) mass spectrometer which substantially eliminates interference with the analysis by ions of mass greater than the highest mass of interest. U.S. Pat. No. 4,883,958 discloses an interface for coupling liquid chromatography to solid or gas phase detectors. An improved technique for TOF mass analysis involving laser desorption is disclosed in U.S. Pat. No. 5,045,694. Matrix-assisted laser desorption mass spectrometry and a two-stage reflectron were discussed in an article in Rapid Communication in Mass Spectrometry, Vol. 5, pp 198-202 (1991). Additional background information regarding time-of-flight mass spectrometry is in a keynote lecture by LeBeyec published in Advances in Mass Spectrometry, Vol. II A, pp 126-145.
The reflectron (or ion mirror) was first described by Mamyrin (Mamyrin, B. A.; Karatajev. V. J.; Shmikk, D. V.; Zagulin, V. A., Sov. Phys., JETP 37 (1973) 45). At the end of the drift region, ions enter a retarding field from which they are reflected back through the drift region at a slight angle. Improved mass resolution results from the fact that ions with larger kinetic energies must penetrate the reflecting field more deeply before being turned around. These faster ions then catch up with the slower ions at the detector and are focused. Reflectrons were used on the laser microprobe instrument introduced by Hillenkamp et al. (Hillenkamp, F.; Kaufmann, R.; Nitsche, R.; Unsold, E., Appl. Phys. 8 (1975) 341) and commercialized by Leybold Hereaus as the LAMMA (LAser Microprobe Mass Analyzer). A similar instrument was also commercialized by Cambridge Instruments as the IA ( Laser Ionization Mass Analyzer). Benninghoven (Benninghoven reflectron) has described a SIMS (secondary ion mass spectrometer) instrument that also utilizes a reflectron, and is currently being commercialized by Leybold Hereaus. A reflecting SIMS instrument has also been constructed by Standing (Standing, K. G.; Beavis, R.; Bollbach, G.; Ens, W.; Lafortune, F.; Main, D.; Schueler, B.; Tang, X.; Westmore, J. B., Anal. Instrumen. 16 (1987) 173).
Lebeyec (Della-Negra, S.; Lebeyec, Y., in Ion Formation from Organic Solids IFOS III, ed. by A. Benninghoven, pp 42-45, Springer-Verlag, Berlin (1986)) described a coaxial reflectron time-of-flight that reflects ions along the same path in the drift tube as the incoming ions, and records their arrival times on a channelplate detector with a centered hole that allows passage of the initial (unreflected) beam. This geometry was also utilized by Tanaka et al. (Tanaka, K.; Waki, H.; Ido, Y.; Akita, S.; Yoshida, T., Rapid Comun. Mass Spectrom. 2 (1988) 151) for matrix assisted laser desorption. Schlag et al. (Grotemeyer, J.; Schlag, E. W., Org. Mass Spectrom. 22 (1987) 758) have used a reflectron on a two-laser instrument. The first laser is used to ablate solid samples, while the second laser forms ions by multiphoton ionization. This instrument is currently available from Bruker. Wollnik et al. (Grix., R.; Kutscher, R.; Li, G.; Gruner, U.; Wollnik, H., Rapid Commun. Mass Spectrom. 2 (1988) 83) have described the use of reflectrons in combination with pulsed ion extraction, and achieved mass resolutions as high as 20,000 for small ions produced by electron impact ionization.
An alternative to reflectrons is the passage of ions through an electrostatic energy filter, similar to that used in double-focusing sector instruments. This approach was first described by Poschenroeder (Poschenroeder, W., Int. J. Mass Spectrom. Ion Phys. 6 (1971) 413). Sakurai et al. (Sakuri, T.; Fujita, Y; Matsuo, T.; Matsuda, H; Katakuse, I., Int. J. Mass Spectrom. Ion Processes 66 (1985) 283) have developed a time-of-flight instrument employing four electrostatic energy analyzers (ESA) in the time-of-flight path. At Michigan State, an instrument known as the ETOF was described that utilizes a standard ESA in the TOF analyzer (Michigan ETOF).
Lebeyec et al. (Della-Negra, S.; Lebeyec, Y., in Ion Formation from Organic Solids IFOS III, ed. by A. Benninghoven, pp 42-45, Springer-Verlag, Berlin (1986)) have described a technique known as correlated reflex spectra, which can provide information on the fragment ion arising from a selected molecular ion. In this technique, the neutral species arising from fragmentation in the flight tube are recorded by a detector behind the reflectron at the same flight time as their parent masses. Reflected ions are registered only when a neutral species is recorded within a preselected time window. Thus, the resultant spectra provide fragment ion (structural) information for a particular molecular ion. This technique has also been utilized by Standing (Standing, K. G.; Beavis, R.; Bollbach, G.; Ens, W.; Lafortune, F.; Main, D.; Schueler, B.; Tang, X.; Westmore, J. B., Anal. Instrumen. 16 (1987) 173).
TOF mass spectrometers do not scan the mass range, but rather record ions of all masses following each ionization event. Nevertheless, this mode of operation has some analogy with the linked scans obtained on double-focusing sector instruments. In both instruments, MS/MS information is obtained at the expense of high resolution. In addition, correlated reflex spectra can be obtained only on instruments which record single ions on each TOF cycle, and are therefore not compatible with methods (such as laser desorption) which produce high ion currents following each laser pulse.
New ionization techniques, such as plasma desorption (Macfarlane, R. D.; Skowronski, R. P.; Torgerson, D. F.; Biochem. Bios. Res. Commun. 60 (1974) 616), laser desorption (VanBreemen, R. B.; Snow, M.; Cotter, R. J., Int. J. Mass Spectrom. Ion Phys. 49 (1983) 35; Van der Peyl, G. J. Q.; Isa, K.; Haverkamp, J.; Kistemaker, P. G., Org. Mass Spectrom. 16 (1981) 416), fast atom bombardment (Barber, M.; Bordoli, R. S.; Sedwick, R. D.; Tyler, A. N., J. Chem. Soc., Chem. Commun. (1981) 325-326) and electrospray (Meng, C. K.; Mann, M.; Fenn, J. B., Z. Phys. D10 (1988) 361), have made it possible to examine the chemical structures of proteins and peptides, glycopeptides, glycolipids and other biological compounds without chemical derivatization. The molecular weights of intact proteins can be determined using matrix assisted laser desorption ionization (MALDI) on a TOF mass spectrometer or electrospray ionization. For more detailed structural analysis, proteins are generally cleaved chemically using CNBr or enzymatically using trypsin or other proteases. The resultant fragments, depending upon size, can be mapped using MALDI, plasma desorption or fast atom bombardment. In this case, the mixture of peptide fragments (digest) is examined directly resulting in a mass spectrum with a collection of molecular ion corresponding to the masses of each of the peptides. Finally, the amino acid sequences of the individual peptides which make up the whole protein can be determined by fractionation of the digest, followed by mass spectral analysis of each peptide to observe fragment ions that correspond to its sequence.
It is in this sequencing of peptides that tandem mass spectrometry may provide major advantages over other available techniques and instrumentation. Generally, most of the new ionization techniques are successful in producing intact molecular ions, but not in producing fragmentation. In a tandem instrument the first mass analyzer passes molecular ions corresponding to the peptide of interest. These ions are activated toward fragmentation in a collision chamber, and their fragmentation products are extracted and focused into the second mass analyzer which records a fragment ion (or daughter ion) spectrum.
A tandem TOFMS consists of two TOF analysis regions with an ion gate between the two regions. The ion gate allows one to gate (i.e. select) ions which will be passed from the first TOF analysis region to the second. As in conventional TOFMS, ions of increasing mass have decreasing velocities and increasing flight times. Thus, the arrival time of ions at the ion gate at the end of the first TOF analysis region is dependent on the mass-to-charge ratio of the ions. If one opens the ion gate only at the arrival time of the ion mass of interest, then only ions of that mass-to-charge will be passed into the second TOF analysis region.
However, it should be noted that the products of an ion dissociation that occurs after the acceleration of the ion to its final potential will have the same velocity as the original ion. The product ions will therefore arrive at the ion gate at the same time as the original ion and will be passed by the gate (or not) just as the original ion would have been.
The arrival times of product ions at the end of the second TOF analysis region is dependent on the product ion mass because a reflectron is used. As stated above, product ions have the same velocity as the reactant ions from which they originate. As a result, the kinetic energy of a product ion is directly proportional to the product ion mass. Because the flight time of an ion through a reflectron is dependent on the kinetic energy of the ion, and the kinetic energy of the product ions are dependent on their masses, the flight time of the product ions through the reflectron is dependent on their masses.
Because TOFMS is a pulsed technique, it is most readily applied with pulsed ion sources such as matrix assisted laser desorption/ionization (MALDI). While mass spectra are readily produced via MALDI-TOF mass spectrometry, such spectra typically have a relatively low mass resolution. The main reason the mass resolution of such instruments is not higher is that the ions have some initial velocity distribution when they are produced. This distribution of initial velocities is the result of the method of ion production and is not readily eliminated.
To compensate the flight times of the ions for this velocity distribution, one may use a method known as delayed extraction (DE) 2, 3!. In performing conventional DE experiments, ions are not accelerated until a set time, T, after ion production has occurred. That is, no accelerating electric field is applied until time T. In cases where DE is useful, the kinetic energy of the ions is a well defined function of the distance of the ion from the sample surface at time T. For example, in MALDI-TOF, between the time of ion production and time T, the ions drift away from the sample surface according to their initial velocities. At time T, the kinetic energy of the ions will be directly proportional to the square of the distance the ions have drifted. Because the ions kinetic energy and position are related, the accelerating electric field applied at time T can be used to simultaneously "space" and "energy" compensate the flight times of the ions. In this way, all ions of a given mass-to-charge ratio will arrive at the detector nearly simultaneously. This results in an improvement in the mass resolution.
As described by Whittal and Li (R. M. Whittal and L. Li, "High Resolution Matrix-Assisted Laser Desorption/Ionization in a Linear Time-of-Flight Mass Spectrometer", Anal. Chem. 67(13), 1950(1995), a time-lag focusing ("TLF") method of ion extraction may be used in a simple linear system to provide mass resolution on a par with a reflectron TOFMS. With conventional MALDI instruments, the ions generated by the laser beam near the surface of the sample probe are extracted by a dc potential. In TLF, a short time delay (under 300 ns) is inserted between the laser ionization and the ion extraction events. The region between the repeller and extraction grid is field-free during the delay. Following the delay, a pulsed potential is applied to the repeller. Application of the appropriate pulse voltage provides the energy correction necessary to simultaneously detect all ions of the same mass/charge regardless of their inital energy. The initially less energetic ions closer to the repeller receive more energy (from the pulsed potential) than the initally more energetic ions further from the repeller at the time the pulse is applied. An energy/spatial correction is said to be provided such that all ions of the same mass/charge reach the detector plane simultaneously.
However, prior art DE does not apply the correct potential gradient to perfectly space and energy focus the ions. Rather in prior art DE, a simple linear field gradient is applied between the sample surface and an extraction grid. This provides only a first order correction for the initial ion velocity distribution. The higher order DE focusing method of the present invention focuses the ions perfectly in space and energy. Consequently, Nth order DE focusing can produce higher mass resolution spectra at lower operating voltages than prior art first order DE.
Other references relating generally to the technology herein disclosed include, for example, F. Hillenkamp, M. Karas, R. C. Beavis, B. T. Chait, Anal. Chem. 63(24), 1193A(1991); Wei Hang, Pengyuan Yag, Xiaoru Wang, Chenglong Yang, Yongxuan Su, and Benli Huang, Rapid Comm. Mass Spectrom. 8, 590(1994); A. N. Verentchikov, W. Ens, K. G. Standing, Anal.Chem. 66, 126(1994); J. H. J. Dawson, M. Guilhaus, Rapid Comm. Mass Spectrom. 3, 155(1989); M. Guilhaus, J. Am. Soc. Mass Spectrom. 5, 588(1994); E. Axelsson, L. Holmlid, Int. J. Mass Spectrom. Ion Process. 59, 231(1984); O. A. Mirgorodskaya, et al., Anal. Chem. 66, 99(1994); S. M. Michael, B. M. Chien, D. M. Lubman, Anal. Chem. 65, 2614(1993); W. C. Wiley, I. H. McLaren, Rev. Sci. Inst. 26(12), 1150(1955); R. C. Beavis and B. T. Chait, Chem. Phys. Lett. 181(5), 479(1991); R. S. Brown and J. J. Lennon, Anal. Chem. 67(13), 1998(1995); R. M. Whittal and L. Li, Anal. Chem. 67(13), 1950(1995).


A semiconductor wafer scrubbing and drying apparatus is capable processing wafers in a vertical orientation from start to finish. The apparatus moves the wafers in a generally vertical direction from an entry station of the apparatus to a dryer of the apparatus. The wafers enter the apparatus in a cassette and exit in another cassette in the same order as they were in the entry cassette to preserve individual wafer identity. The apparatus is constructed so that the compartment in which the wafers are handled is isolated and the components handling the wafers in that compartment are made of a fluorinated plastic. The actuators driving the motion of the wafer handling components are located in another compartment. A rinsing device in the wafer handling compartment is activated and deactivate for rinsing one of the wafers without the use of valves in the rinse line.

This invention relates generally to apparatus for use in cleaning semiconductor wafers and more particularly to apparatus for use in cleaning wafers which protects the wafers from particle contamination during the cleaning process.
As is known, contaminates on the surface of a semiconductor wafer will adversely affect the electrical properties of the wafer. Therefore, it is of the utmost importance that the wafer surface be substantially free of particulate and other contaminates. Thus, at least the final stage of semiconductor wafer manufacture involves cleaning the wafer to remove the contaminates. Many methods are available for cleaning the wafers, including both chemical and mechanical processes as well as ultrasonic processes. Even with mechanical cleaning some liquids are used to facilitate the process. Therefore, it is always necessary to dry the wafers once cleaned.
The exacting standards of cleanliness required in the semiconductor industry (e.g., no more than 10 particles on the wafer greater than 0.2 micrometers in diameter) create unique problems for wafer cleaning. For example, the cleaning process itself can cause contaminates to deposit on the wafer surface as the wafer is handled. The conventional automated cleaning method processes wafers in a horizontal position. A wafer transport which holds the wafer as it is cleaned typically comprises a vacuum chuck or O-ring belt which engages one face of the wafer. Heretofore, the motors, belts, bearings and other mechanical parts used to clean the wafers were in close proximity to the wafer itself. These parts are sources of particulate and metallic contamination of the wafers in the cleaning apparatus. Moreover, the horizontal orientation of the wafers presents a large surface area perpendicular to the direction of flow of air through the cleaning apparatus. Thus, the surface is more likely to capture particles entrained in the air flow.
There are presently some vertical cleaning apparatus such as shown by Kudo et al., U.S. Pat. No. 5,317,778. However, the Kudo et al. apparatus receives wafers in a horizontal orientation and then moves them to a vertical orientation. As a result grippers having opposing members must be used to grip the wafers on opposing sides for moving them to a vertically upright position. The greater the area of the wafer contacted by the gripper member, the greater the chance for contamination of the wafer. Moreover, Kudo et al. rely upon infrared drying which evaporates liquid from the surface of the wafer. Evaporative drying leaves behind on the wafer contaminants which were suspended or dissolved in the wafer cleaning or rinsing liquids.


A method includes identifying multiple statistics associated with each of multiple wireless connections. The multiple wireless connections form a single communication path between two wireless nodes in a wireless network. The method also includes identifying an overall quality associated with the communication path using the statistics. The method can also include assigning a quality value to each statistic for each wireless connection, where the overall quality is based on at least one of the quality values assigned to the statistics (such as a lowest of the quality values). The statistics could include a Received Signal Quality Indicator (RSQI), a Received Signal Strength Indication (RSSI), and a transmit success/fail ratio. The quality value assigned to each statistic could include a “good” quality, a “fair” quality, or a “poor” quality.

Wireless networks are frequently used in industrial process control systems. For example, a process control system often includes sensors that provide measurements over a wireless network and actuators that receive control signals over the wireless network. A process controller can use the measurements from the sensors to generate the control signals for the actuators.
A wireless network may contain any number of communication paths between different devices in the network. Communication paths may be unidirectional (having one unidirectional connection between devices) or bidirectional (having two unidirectional connections between devices, one in each direction). A user may wish to measure or monitor the quality of individual communication paths within the network. There are several statistics that can be used to measure the quality of a wireless connection, including a Received Signal Quality Indicator (RSQI), a Received Signal Strength Indication (RSSI), or a transmit success/fail ratio. Statistics typically apply to a single unidirectional connection.

Apparatus and method for reporting of communication path quality within a wireless network


A hot channel distributor arrangement for a hot channel system that can particularly be heated during a heating phase, which is designed to supply plastic melt from a pour-in opening for at least two nozzle arrangements that can be moved relative to and independently of one another, each having at least one outlet opening in the region of a nozzle body, wherein at least one main distributor block having at least one main distributor arm is provided, said main distributor block being rotatable around a first rotational axis, wherein at least one auxiliary distributor block is arranged on the at least one main distributor block, said auxiliary distributor block forming at least one auxiliary distributor arm and being rotatable around a second rotational axis, wherein an angle between the main distributor block and the auxiliary distributor block is adjustable, wherein at least one of the nozzle arrangements is provided on each auxiliary distributor arm, and wherein the angle between the main distributor arm and auxiliary distributor arm changes due to thermal expansion at least during the heating phase.

The disclosure relates to a hot channel distributor arrangement for a hot channel system.
Reference is made at first to DE 29 38 832 concerning the general technological background of the technology of hot channel systems.
In order to injection-mold several mold cavities, several nozzle arrangements are required, which are optionally provided with sealing needles, whose positions are to be adjusted to those of the respective mold cavities.
A hot channel injection system is described in U.S. Pat. No. 5,540,580, which is configured for so-called "blow molding", i.e. for a blow injection method, in order to produce hollow containers such as plastic bottles. It is disclosed in U.S. Pat. No. 5,540,580 that several distributor blocks can movably be arranged with respect to each other, wherein the pressing pressure between the inlet or pour-in opening of the main distributor channel system and the only outlet can be used in order to seal the arrangement.
Reference is further made to U.S. Pat. No. 5,000,675. It discloses that several nozzle arrangements, which are respectively pivotable about two rotational axes, are arranged on a distributor block. The nozzle arrangements respectively comprise an outlet opening for the melt, from which the melt exits or is guided into mold cavities of an injection mold. The pivotable nozzle arrangements must be fixed in their respective position by two clamping jaws which are penetrated by screws. The limited local mobility of the nozzle arrangements and bodies is an impediment to many applications. Also, the fixing of the nozzle arrangement in its end position for performing the actual injection process is inadequate for the prevailing high pressures. In particular, it is impossible to provide a longitudinal adjustment of the nozzle arrangements relative to each other and thus no compensation for thermal expansion is provided for. Thus, the components of the system are loaded by the high pressures which are necessary for injection molding, and must also additionally accommodate the tensions which are produced by thermal expansion. These high loads have a negative influence on the operational lifespan of the hot channel system.
It is intended to provide an improved multi-nozzle hot channel distributor arrangement as compared to the aforementioned state of the art, which permits a substantially independent adjustment of several hot channel nozzles over a relatively large surface area in a simpler way and which substantially prevents the build-up of thermal tensions in the hot channel system.

Hot channel distributor arrangement for a hot channel system


The present invention relates to a method for predicting an optimum transmission frame size in a wireless computer network. The method comprises assessing transmission channel quality in the network, calculating an optimum length for the transmission frame, adjusting the length of the transmission frame to the predicted optimum length, transmitting the frame at its adjusted length and assessing the quality of the transmission of the frame. Prediction of the optimum frame size employs a Kalman filter which employs the parameters of bit error rate and random processing noise in the calculation of the predicted optimum frame length.

Modern networks continue to provide electronic devices the ability to communicate with other devices. The continuing growth of networking systems and technology seems limitless and the speed of networked communications has brought benefits to nearly every human endeavor. Local Area Networking (LAN), particularly, is evolving rapidly into wireless connectivity and bringing another level of performance and convenience to the home and business networking environment.
Networks, even if relatively small, can consist of enormous numbers of devices. The complexity of networks continues to expand as does the application of network concepts to more and more disciplines and environments. With the growing market for wireless data networks, there is considerable interest in integrating the support of new services such as wireless voice telephony, MP3 and other demanding protocols.
In wireless data networking, whether implemented by RF or infrared technology, data are transmitted over channels in data frames. The rate of frame transmission varies with volume of transmissions throughout the network. The quality of a channel, which is analogous to the rate at which a channel is able to carry data frames error free, varies over time due to burst errors or changes in the operating environment. At times, usually the times of highest demand, channel quality can cause channel efficiency to be very low. This time-varying channel quality, and thus channel efficiency, is not addressed in wireless network standards such as the current IEEE 802.11 specifications. Many Quality-of-Service (QoS) requirements are thus very difficult to achieve. Note that IEEE 802.11 is the emerging standard for wireless network data communications.
In wireless networking, the frame size and bit-error rate (BER) affect the channel efficiency. There is an optimum frame size which depends on the channel quality. When the channel quality is good, the frame size can be larger, and when channel quality is bad, large frame size will cause very high frame-error-rate (FER). However, if the frame size selected is too small, the channel efficiency will be lowered because of the fixed overhead in the header of the frame. In current wireless and mobile networks, there is no method for adjusting the frame size dynamically in order to maintain any specified channel efficiency. Since the channel quality is time-varying due to multipath fading, path loss, and other factors, the prevalent static frame size schemes result in the loss of overall system performance.
What is needed, then, is a method for dynamically varying the data frame size in an operating network. Such a method must adjust frame size to the optimum size based on predictions of optimum frame size in a noisy wireless network environment.

Optimum frame size predictor for wireless Local Area Network