Abstract: A process for preparing nanoparticles and microparticles is provided. The process involves forming a mixture of a polymer and a solvent, wherein the solvent is present in a continuous phase and introducing the mixture into an effective amount of a nonsolvent to cause the spontaneous formation of microparticles.

Abstract: A vertical cavity, surface emitting laser (VCSEL) device (10, 10′) has a substrate (12) and, disposed over a surface of the substrate, a Group III nitride buffer layer (14) and a mesa structure containing at least a portion of an n-type Group III nitride layer (16). The VCSEL device and mesa structure further include a first multilayer dielectric mirror stack (18a), that is embedded within the first Group III nitride layer by the use of a lateral edge overgrowth (LEO) process; a p-type Group III nitride layer (26); and a p-n junction between the n-type Group III nitride layer and the p-type Group III nitride layer. The p-n junction contains an active multiquantum well region (24). Also contained in the mesa structure is a dielectric (silicon dioxide) layer (20) having a current constricting aperture (20a). The dielectric layer and aperture are buried within one of the n-type Group III nitride layer or the p-type Group III nitride layer, also by the use of the LEO process.

Abstract: Bioadhesive polymers in the form of, or as a coating on, microcapsules containing drugs or bioactive substances which may serve for therapeutic, or diagnostic purposes in diseases of the gastrointestinal tract, are described. The polymeric microspheres all have a bioadhesive force of at least 11 mN/cm2 (110 N/m2). Techniques for the fabrication of bioadhesive microspheres, as well as a method for measuring bioadhesive forces between microspheres and selected segments of the gastrointestinal tract in vitro are also described. This quantitative method provides a means to establish a correlation between the chemical nature, the surface morphology and the dimensions of drug-loaded microspheres on one hand and bioadhesive forces on the other, allowing the screening of the most promising materials from a relatively large group of natural and synthetic polymers which, from theoretical consideration, should be used for making bioadhesive microspheres.

Abstract: A method for characterizing a sample includes the steps of (a) providing a semiconductor material; (b) applying at least one of an electric field, a pulsed or cw light source, a change in temperature and/or a change in pump pulse intensity to the semiconductor material; (c) absorbing pump light pulses in a portion of the semiconductor material and measuring changes in optical constants as indicated by probe light pulses applied at some time t following the absorption of the pump light pulses; and (e) associating a measured change in the optical constants with at least one of a surface charge, dopant concentration, trap density, or minority carrier lifetime.

Abstract: A method for characterizing a sample comprising the steps of depositing the sample on a substrate, measuring a first change in optical response of the sample, changing the lateral strain of the sample, measuring a second change in optical response of the sample, comparing the second change in optical response of with the first change in optical response and associating a difference between the second change and the first change in optical response with a property of interest in the sample. The measurement of the first change in optical response is made with the sample having an initial lateral strain. The measurement of the second change in optical response is made after the lateral strain in the sample is changed from the initial lateral strain to a different lateral strain. The second change in optical response is compared to the first change in optical response to find the difference between the second change and the first change.

Abstract: Disclosed is a system for the characterization of thin films and interfaces between thin films through measurements of their mechanical and thermal properties. In the system light is absorbed in a thin film or in a structure made up of several thin films, and the change in optical transmission or reflection is measured and analyzed. The change in reflection or transmission is used to give information about the ultrasonic waves that are produced in the structure. The information that is obtained from the use of the measurement methods and apparatus of this invention can include: (a) a determination of the thickness of thin films with a speed and accuracy that is improved compared to earlier methods; (b) a determination of the thermal, elastic, and optical properties of thin films; (c) a determination of the stress in thin films; and (d) a characterization of the properties of interfaces, including the presence of roughness and defects.

Abstract: A method for the determination of grain size in a thin film sample comprising the steps of measuring first and second changes in the optical response of the thin film, comparing the first and second changes to find the attenuation of a propagating disturbance in the film and associating the attenuation of the disturbance to the grain size of the film. The second change in optical response is time delayed from the first change in optical response.

Abstract: Implantable therapy systems are disclosed for the local and controlled delivery of a biologically active factor to the brain, spinal cord and other target regions of a subject suffering from a dibilatating condition. The method of the invention involves surgically exposing an insertion site, generally located above a predetermined treatment site (12), in a patient. A cannula (20), having an obturator (30) or dilator (104) positioned therein, is inserted at the insertion site, defining a pathway to the treatment site. In some instances, the cannula can be inserted along the path of a guidewire (102) previously positioned at the treatment site. The cannula (20) is preferably a low friction polymeric material such as polytetrafluoroethylene. The cannula (20) generally has an open proximal end for receiving the obturator (30) or dilator (104), and an open distal end, preferably a tapered end, for delivery of neurologically active factors to the treatment site (12).

Abstract: Disclosed is a system for the characterization of thin films and interfaces between thin films through measurements of their mechanical and thermal properties. In the system light is absorbed in a thin film or in a structure made up of several thin films, and the change in optical transmission or reflection is measured and analyzed. The change in reflection or transmission is used to give information about the ultrasonic waves that are produced in the structure. The information that is obtained from the use of the measurement methods and apparatus of this invention can include: (a) a determination of the thickness of thin films with a speed and accuracy that is improved compared to earlier methods; (b) a determination of the thermal, elastic, and optical properties of thin films; (c) a determination of the stress in thin films; and (d) a characterization of the properties of interfaces, including the presence of roughness and defects.

Abstract: Methods and compositions are provided for enhancing the bioadhesive properties of polymers used in drug delivery systems. The bioadhesive properties of a polymer are enhanced by incorporating an anhydride oligomer into the polymer to enhance the ability of the polymer to adhere to a tissue surface such as a mucosal membrane. Anhydride oligomers which enhance the bioadhesive properties of a polymer include oligomers synthesized from dicarboxylic acid monomers, preferably those found in Krebs glycolysis cycle, especially fumaric acid. The oligomers can be incorporated within a wide range of polymers including proteins, polysaccharides and synthetic biocompatible polymers. In one embodiment, anhydride oligomers can be incorporated within polymers used to form or coat drug delivery systems, such as microspheres, which contain a drug or diagnostic agent. The oligomers can either be solubilized and blended with the polymer before manufacture or else used as a coating with polymers over existing systems.

Abstract: Encapsulated viable cells for implanting are prepared having cells dispersed in a particulate, essentially non cross-linked chitosan core matrix that is enclosed within a semipermeable membrane. The cells are entrapped between chitosan particles of the core matrix and there is essentially no interfacial cross-linking between the core matrix and the membrane. The core matrix provides a physical support for the cells such that the cells are evenly dispersed throughout the core matrix so as to allow their maintenance, growth, proliferation and differentiation. The encapsulated cells may be prepared by mixing viable cells with a solution of chitosan, encapsulating the resultant mixture in a thermoplastic semipermeable membrane, and causing the chitosan to precipitate such as by changing the pH to form the core matrix. Alternatively, the chitosan in solution is precipitated to form the core matrix containing cells, and the core matrix is encapsulated in a semipermeable membrane.

Abstract: An apparatus and method for improving the properties of carbon-containing fly ash through ozonation is described. The apparatus includes a chamber for containing the fly ash and an ozonator that generates an ozone-containing gas. The ozonator supplies the ozone-containing gas such that it enters the chamber with the fly ash and deactivates carbon within the fly ash. Afterwards, the fly ash will have decreased surfactant adsorptivity so that it can be effectively mixed with cement or whatever other materials may require fly ash with passivated carbon.

Abstract: A sealed, implantable, encapsulation device (20) for diffusing a biologically active product or function to an individual which includes a substantially non-porous fitting (32) including an inner surface (33) defining an access port (34). A permselective, porous, membrane (21), having an interior surface (22), cooperates with the fitting inner surface (33) to form a storage cavity (23) therebetween. The membrane interior surface (22) is in substantially cell-tight dry sealing engagement with fitting (32) to seal cavity (23). Living cells (24) are disposed in the cavity (23) which are capable of secreting the biologically active product to an individual. The membrane (21) is of a material capable of permitting the passage of substances between the individual and cells required to provide the biological product or function. A plug member (35) is positioned in the access port (34) and seated in cell-tight sealing engagement with the fitting inner surface (33).

Abstract: Methods and compositions are provided for enhancing the bioadhesive properties of polymers used in drug delivery devices. The bioadhesive properties of a polymer are enhanced by incorporating a metal compound into the polymer to enhance the ability of the polymer to adhere to a tissue surface such as a mucosal membrane. Metal compounds which enhance the bioadhesive properties of a polymer include water-insoluble metal compounds such as water-insoluble metal oxides, including oxides of calcium, iron, copper and zinc. The metal compounds can be incorporated within a wide range of polymers including proteins, polysaccharides and synthetic biocompatible polymers. In one embodiment, metal oxides can be incorporated within polymers used to form or coat drug delivery devices, such as microspheres, which contain a drug or diagnostic agent.

Abstract: An optical fiber structure includes: an optical fiber comprising a rare earth doped core (that may be single mode or multi-mode), or several single mode cores, surrounded by a silica material; a glass cylinder tube containing the optical fiber along a length thereof such that the doped core is located at a center of the glass cylinder for a single core, or arranged geometrically around the center for multiple cores; and a support structure disposed between the light guiding section of the optical fiber optical fiber and an inner wall of the tube that functions as a portion of the support structure of the light guiding portion of the optical fiber. The support structure is arranged such that the effective cladding of the core is a gas contained between the optical fiber and the inner wall of the tube for providing the optical fiber with a numerical aperture that is approximately one. A polarization maintaining embodiment is described, as are methods for fabricating the optical fiber structures.

Abstract: Immortalized cell lines of retinal origin (retinal endothelial and retinal pigmentary epithelial origin) which are capable of being implanted in the retina and of conveying a substance of therapeutic interest into the eye and the central nervous system. Such lines can also serve as a model for studying the blood/central nervous system interfaces.These lines are derived from primary cultures of retinal cells selected from the group comprising the primary retinal endothelial cells and the primary retinal epithelial cells, comprise a nucleic acid fragment containing at least one immortalizing fragment of a heat-sensitive viral oncogene, which nucleic acid fragment may be associated with at least one selection gene, and exhibit the morphological characteristics and at least the surface antigen expression characteristics of the corresponding primary culture cells.

Abstract: An immunoisolatory vehicle for the implantation into an individual of cells which produce a needed product or provide a needed metabolic function. The vehicle is comprised of a core region containing isolated cells and materials sufficient to maintain the cells, and a permselective, biocompatible, peripheral region free of the isolated cells, which immunoisolates the core yet provides for the delivery of the secreted product or metabolic function to the individual.

Abstract: Modified PKS gene clusters which produce novel polyketides in an efficient system in a host cell or in a cell free extract are described.

Abstract: A method for the determination of grain size in a thin film sample comprising the steps of measuring first and second changes in the optical response of the thin film, comparing the first and second changes to find the attenuation of a propagating disturbance in the film and associating the attenuation of the disturbance to the grain size of the film. The second change in optical response is time delayed from the first change in optical response.

Abstract: A conformal identification apparatus is disclosed. The apparatus presents to an observer through an aided eye at least first and second representational objects corresponding to first and second actual objects. The apparatus includes a map that contains the first and second representational objects; a magnifier disposed between the map and the aided eye that presents a magnified image of a portion of the map including the first and second representational objects; and a support structure that supports the map and the magnifier. The apparatus enables the observer to view the first and second actual objects through an unaided eye simultaneously with viewing the magnified image with the aided eye.