摘要:
A hydratable, highly absorbent keratin solid fiber or powder capable of absorbing a large weight excess of water may be produced by partially oxidizing hair keratin disulfide bonds to sulfonic acid residues and reacting the sulfonic acid residues with a cation. The neutralized suspension can be filtered, washed, and dried, leaving keratin solid which can be shredded into fibers and further ground into powder. Addition of water to the solid produces a hydrogel. The powder or hydrogel may be useful as an absorbent material, as a therapeutic for skin, or as an excipient. The keratin materials can be incorporated into nonwoven films. Another use for the hydrogel is as a biocompatible viscoelastic filler for implant applications.
摘要:
A sheet wound dressing formed of cross linked keratin. An insoluble, largely Beta keratin fraction from human hair is acidified to a low pH, preferably less than about 3, which partially solubilizes the keratin by weakening hydrogen bonds. The suspension is added to base, such as ammonium hydroxide, forming a slurry. The slurry is cast directly onto a flat surface, allowing the re-formation of cross-links including hydrogen bonds and disulfide bonds. The resulting cross-linked keratin sheet can be used as a sheet wound dressing or as a scaffolding for growth of cells. The insoluble keratin can be derived from human hair which is washed, rinsed, dried, chopped and treated with peracetic acid to break some accessible disulfide linkages. The treated hair is filtered, rinsed, dried, and ground into a keratin powder. The keratin powder is suspended in a mixture of ammonium hydroxide and ammonium thioglycollate and heated sufficiently to dissolve the soluble keratin fraction, followed by cooling and centrifugation to concentrate the insoluble, largely Beta keratin fraction.
摘要:
The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.
摘要:
A high sample rate cosine filter eliminates DC components by summing them such that they sum to zero. A non-orthogonal cosine filter is also provided. When the cosine filter is applied for N=4 samples per cycle, the samples are separated by 90 degrees. However, at higher sampling rates, it is not necessary to wait for 90 degrees to estimate the phasor value. Non-orthogonal components are used to estimate the phasor value. The time delay associated with the cosine filter is reduced in the process.
摘要:
The present invention relates to an electric valve capable of producing podic mass-flow modulation of a gaseous, liquid, or mixed-phase medium over wide ranges of frequencies, pressure, and flow rates. Such mass-flow modulation can be used to periodically shed large-scale vortices at the outlet and to manipulate their dynamics allowing the user to actively control fluid mixing and transport further downstream. The device has a piezoelectric wafer that in a relaxed state abuts the upstream end of the outlet tube separating the pressurized fluid in the plenum with the outlet. The device has an apparatus for applying electric field to the wafer, which distorts the wafer and ruptures the seal forming a throat area that controls the fluid mass flux. Due to the fast response of the piezoelectric material to an electric field, the throat area can be modulated rapidly in time making the device operable even at high frequencies. The present invention is particularly useful for actively controlling fuel-air mixing in a combustor. However, it may be utilized in other applications such as in medical drug administration for inhalation therapy.
摘要:
An adapter allows the interconnection of a sensor originating from one manufacturer to be coupled with conventionally incompatible monitors originating from other manufacturers to form a properly functioning pulse oximetry system. The adapter matches a sensor driver in a monitor to the current requirements and light source configuration of a sensor. The adapter also matches a sensor's light detector signal level to the dynamic range requirements of a monitor preamplifier. Further, the adapter provides compatible sensor calibration, sensor type and security information to a monitor. The adapter may have a self-contained power source or it may derive power from the monitor, allowing both passive and active adapter components. The adapter is particular suited as an adapter cable, replacing a conventional patient cable or sensor cable as the interconnection between a sensor to a monitor in a pulse oximetry system.
摘要:
Describes a polymerizable organic composition comprising at least one polymerizable monomer having at least two ethylenically unsaturated groups, e.g., divinyl benzene, and a polythiol monomer represented by the following general formula, ##STR1## wherein R.sub.1 and R.sub.2 are each selected from the group consisting of straight or branched chain alkylene, e.g., methylene or ethylene, cyclic alkylene, phenylene and C.sub.1 -C.sub.9 alkyl substituted phenylene. Optionally, a monoethylenically unsaturated monomer, e.g., phenoxyethyl methacrylate, and/or an anhydride monomer, e.g., methacrylic anhydride, may also be present. Polymerizates prepared from polymerizable organic compositions of the present invention have a refractive index of at least 1.57, an Abbe number of at least 33 and an initial Barcol hardness of at least 1. Also described are photochromic articles prepared from such compositions.
摘要:
A process for treating fillers, preferably precipitated silica, to improve the physical property profile of heat curable and room temperature vulcanizable silicone rubbers and a composition for room temperature vulcanizable rubbers comprising the silica filler treated by the process of the invention.
摘要:
Novel bacterial isolates of B. thuringiensis are disclosed which have enhanced toxicity with respect to previously resistant or insufficiently susceptible insect species, including, but not limited to, Plutella xylostella, Spodoptera frugiperda and Spodoptera exigua, as well as certain secondary pests such as Trichoplusia ni. Such isolates may be characterized by their possession of a particular subset of the genes coding for the various B. thuringiensis .delta.-endotoxin proteins and by a characteristic plasmid profile, or array, known to be associated therewith. Also disclosed are a method for the efficient identification of such bacterial isolates utilizing generalized or, alternatively, gene-specific DNA probes; cloned or synthesized nucleotide sequences which are useful in the preparation of those probes; compositions containing an insecticidally effective amount of a bacterial isolate of the invention in combination with an acceptable carrier; and a method for the use thereof in the control or eradication of insect pests.
摘要:
A method and apparatus is disclosed for texturizing magnetic storage disks. The disk texturizing apparatus utilizes a combination of servomotors for rotating the disk and oscillating the disk towards and away from a texturizing media. The servomotors are controlled by a closed-loop control system which monitors and synchronizes the angular and linear position of the disk. Through such control, the disk rotation speed may be modulated in conjunction with the linear oscillation, thereby allowing a higher degree of triangularity in the texturization pattern. A pattern generation system and a graphical user interface for specifying, modeling, generating, modifying and displaying disk texturizing patterns are also disclosed. The texturizing pattern may be displayed in polar plot and linear plot form so that the user can more easily visualize and design the texturizing pattern. Warning signals are used when the texturizing pattern exceeds the acceleration or amplitude limitations of the physical texturizing apparatus, or when the designed pattern repeats. The pattern generation system may also be used to generate a data sequence describing a particular pattern which is exportable to the physical disk texturizing apparatus.