Abstract: Asymmetric lumen catheter devices are disclosed. In one aspect of the invention, a catheter assembly includes a first catheter tube having a first lumen extending longitudinally through the first catheter tube and a second catheter tube attached to the first catheter tube. The second catheter tube extends a longitudinal length beyond a distal end of the first catheter tube and has a second lumen extending longitudinally therethrough. The first lumen has a larger cross-sectional size than the second lumen.

Abstract: Multi-lumen catheter devices having at least one split-tipped end are disclosed, together with methods of forming such split tip catheters. In one aspect of the invention, the manufacturing methods can include the steps of: providing a catheter body having at least a first and a second internal lumen extending longitudinally through the catheter body; removing a distal portion of the catheter body to form a first distal tip segment such that the first lumen extends longitudinally within this tip segment beyond the second lumen; and joining a second lumen tip segment to the catheter body in communication with the second lumen. The second tip segment can be joined to the catheter body such that it is at least partially separated from the first tip segment and, in some embodiments, preferably diverges at an angle relative to the first tip segment.

Abstract: The present invention provides nanophotovoltaic devices having sizes in a range of about 50 nm to about 5 microns, and method of their fabrication. In some embodiments, the nanophotovoltaic device includes a semiconductor core, e.g., formed of silicon, sandwiched between two metallic layers, one of which forms a Schottky barrier junction with the semiconductor core and the other forms an ohmic contact therewith. In other embodiment, the nanophotovoltaic device includes a semiconductor core comprising a p-n junction that is sandwiched between two metallic layers forming ohmic contacts with the core.

Abstract: Methods and apparatus are disclosed for inserting flexible, multi-lumen catheters into blood vessels, and in particular, for inserting flexible, split-tip catheters into blood vessels. The invention accomplishes these objects by temporarily stiffening each catheter lumen and tip independently through use of intra-catheter stiffener elements disposed within the catheter lumens. This provides means for advancing the catheter/stiffeners assembly through a subcutaneous tunnel, and over a plurality of guidewires until a distal tip of the catheter is at a desired position within the vessel. The intra-catheter stiffener elements are sufficiently stiffening to allow advancing the catheter over guidewires, but sufficiently flexible to allow bending and looping of the catheter for proper placement within the vessel.

Abstract: Means and methods for producing surface-activated semiconductor nanoparticles suitable for in vitro and in vivo applications that can fluoresce in response to light excitation. Semiconductor nanostructures can be produced by generating a porous layer in semiconductor substrate comprising a network of nanostructures. Prior or subsequent to cleavage from the substrate, the nanostructures can be activated by an activation means such as exposing their surfaces to a plasma, oxidation or ion implantation. In some embodiments, the surface activation renders the nanostructures more hydrophilic, thereby facilitating functionalization of the nanoparticles for either in vitro or in vivo use.

Abstract: The present invention provides nanophotovoltaic devices having sizes in a range of about 50 nm to about 5 microns, and method of their fabrication. In some embodiments, the nanophotovoltaic device includes a semiconductor core, e.g., formed of silicon, sandwiched between two metallic layers, one of which forms a Schottky barrier junction with the semiconductor core and the other forms an ohmic contact therewith. In other embodiment, the nanophotovoltaic device includes a semiconductor core comprising a p-n junction that is sandwiched between two metallic layers forming ohmic contacts with the core.

Abstract: Splitable-tip catheters are disclosed with bioresorbable adhesive to provide spatial separation of distal tip elements during use. The invention can be particularly useful in hemodialysis applications where it is desirable to separate blood extraction and return lumens. The adhesive facilitates insertion of the distal end of the catheter as an assembly, e.g., into a blood vessel using a single guidewire, while the bioresorbable nature of the adhesive allows the tip elements to separate in vivo.

Abstract: Methods are disclosed generally directed to design and synthesis of quantum dot nanoparticles having improved uniformity and size. In a preferred embodiment, a release layer is deposited on a semiconductor wafer. A heterostructure is grown on the release layer using epitaxial deposition techniques. The heterostructure has at least one layer of quantum dot material, and optionally, one or more layers of reflective Bragg reflectors. A mask is deposited over a top layer and reactive ion-beam etching applied to define a plurality of heterostructures. The release layer can be dissolved releasing the heterostructures from the wafer. Some exemplary applications of these methods include formation of fluorophore materials and high efficiency photon emitters, such as quantum dot VCSEL devices. Other applications include fabrication of other optoelectronic devices, such as photodetectors.

Abstract: Methods are disclosed generally directed to design and synthesis of quantum dot nanoparticles having improved uniformity and size. In a preferred embodiment, a release layer is deposited on a semiconductor wafer. A heterostructure is grown on the release layer using epitaxial deposition techniques. The heterostructure has at least one layer of quantum dot material, and optionally, one or more layers of reflective Bragg reflectors. A mask is deposited over a top layer and reactive ion-beam etching applied to define a plurality of heterostructures. The release layer can be dissolved releasing the heterostructures from the wafer. Some exemplary applications of these methods include formation of fluorophore materials and high efficiency photon emitters, such as quantum dot VCSEL devices. Other applications include fabrication of other optoelectronic devices, such as photodetectors.

Abstract: The present invention provides orthopedic prosthesis having at least one metallic component that includes a metallic substrate on which an integrally formed nano-crystalline coating is formed. The coating and the substrate have at least one metallic constituent in common having an average atomic concentration in the coating that differs from an average atomic concentration in the substrate by less than about 10 percent. Further, the nano-crystalline coatings includes crystalline grains with an average size in a range of about 1 to 999 nanometers, and more preferably in a range of about 10 to 200 nanometers. A transition region that exhibits a graded reduction in average grain size separates the coating from the substrate. The coating advantageously exhibits an enhanced hardness, and a high degree of resistance to corrosion and wear. In one application, the nano-crystalline coatings of the invention are utilized to form articulating surfaces of various orthopedic devices.

Abstract: The present invention provides nanophotovoltaic devices having sizes in a range of about 50 nm to about 5 microns, and method of their fabrication. In some embodiments, the nanophotovoltaic device includes a semiconductor core, e.g., formed of silicon, sandwiched between two metallic layers, one of which forms a Schottky barrier junction with the semiconductor core and the other forms an ohmic contact therewith. In other embodiment, the nanophotovoltaic device includes a semiconductor core comprising a p-n junction that is sandwiched between two metallic layers forming ohmic contacts with the core.

Abstract: The present invention provides orthopedic prosthesis having at least one metallic component that includes a metallic substrate on which an integrally formed nano-crystalline coating is formed. The coating and the substrate have at least one metallic constituent in common having an average atomic concentration in the coating that differs from an average atomic concentration in the substrate by less than about 10 percent. Further, the nano-crystalline coatings includes crystalline grains with an average size in a range of about 1 to 999 nanometers, and more preferably in a range of about 10 to 200 nanometers. A transition region that exhibits a graded reduction in average grain size separates the coating from the substrate. The coating advantageously exhibits an enhanced hardness, and a high degree of resistance to corrosion and wear. In one application, the nano-crystalline coatings of the invention are utilized to form articulating surfaces of various orthopedic devices.

Abstract: Methods and apparatus are disclosed for detecting solar cell defects by applying a forward-biasing electric current through a silicon solar cell or a group of interconnected solar cells for a short duration and then analyzing the resulting thermal image of each cell with an infrared (IR) camera. The invention is particularly useful in assembling solar cell arrays or modules in which large numbers of cells are to be wired together. Automated module assemblers are disclosed in which the cells (or strings of cells) are tested for defects prior to final module assembly.

Abstract: The present invention provides orthopedic prosthesis having at least one metallic component that includes a metallic substrate on which an integrally formed nano-crystalline coating is formed. The coating and the substrate have at least one metallic constituent in common having an average atomic concentration in the coating that differs from an average atomic concentration in the substrate by less than about 10 percent. Further, the nano-crystalline coatings includes crystalline grains with an average size in a range of about 1 to 999 nanometers, and more preferably in a range of about 10 to 200 nanometers. A transition region that exhibits a graded reduction in average grain size separates the coating from the substrate. The coating advantageously exhibits an enhanced hardness, and a high degree of resistance to corrosion and wear. In one application, the nano-crystalline coatings of the invention are utilized to form articulating surfaces of various orthopedic devices.

Abstract: The present invention provides a catheter having an x-ray generator unit at its tip which generates x-ray radiation having a wavelength in a range effective for treating biological tissue. In one embodiment, the x-ray generator unit includes a miniature x-ray generator and a miniature transformer that form, in combination, a monolithic device. The transformer includes a primary winding that receives an input voltage in a range of 100 V to 4 kV from a power source, via a flexible cable that runs from the proximal end of the catheter body to its distal end. The transformer further includes a secondary winding that up-converts the input voltage to generate an output voltage in a range of 10 kV to 40 kV to be applied to a cathode of the x-ray generator. The cathode emits electrons in response to the applied voltage, and an extraction electrode guides the emitted electrons to an anode, which is preferably formed of a high-Z refractory metal.

Abstract: The present invention provides a catheter having an x-ray generator unit at its tip which generates x-ray radiation having a wavelength in a range effective for treating biological tissue. In one embodiment, the x-ray generator unit includes a miniature x-ray generator and a miniature transformer that form, in combination, a monolithic device. The transformer includes a primary winding that receives an input voltage in a range of 100 V to 4 kV from a power source, via a flexible cable that runs from the proximal end of the catheter body to its distal end. The transformer further includes a secondary winding that up-converts the input voltage to generate an output voltage in a range of 10 kV to 40 kV to be applied to a cathode of the x-ray generator. The cathode emits electrons in response to the applied voltage, and an extraction electrode guides the emitted electrons to an anode, which is preferably formed of a high-Z refractory metal.

Abstract: The present invention provides methods and apparatus for creating insulating layers in Group III-V compound semiconductor structures having aluminum oxide with a substantially stoichiometric compositions. Such insulating layers find applications in a variety of semiconductor devices. For example, in one aspect, the invention provides vertical insulating layers separating two devices, such as photodiodes, formed on a semiconductor substrate from one another. In another aspect, the invention can provide such insulating layers as buried horizontal insulating layers of semiconductor devices.

Abstract: A synovial prosthetic member includes a body having an articulating surface and an anchor surface, the articulating surface being configured for articulation with another articulating surface of a synovial joint, the anchor surface being configured for cementing to bone, the body being composed of ultrahigh molecular weight polyethylene (UHMWPE), the anchor surface having been subjected to treatment by either ion implantation, ion beam assisted deposition, or sputter deposition.

Abstract: A synovial prosthetic member includes a body having an articulating surface and an anchor surface, the articulating surface being configured for articulation with another articulating surface of a synovial joint, the anchor surface being configured for cementing to bone, the body being composed of ultrahigh molecular weight polyethylene (UHMWPE), the anchor surface having been subjected to treatment by either ion implantation, ion beam assisted deposition, or sputter deposition.

Abstract: A heteroepitaxial semiconductor device having reduced density of threading dislocations and a process for forming such a device. According to one embodiment, the device includes a substrate which is heat treated to a temperature in excess of 1000.degree. C., a film of arsenic formed on the substrate at a temperature between 800.degree. C. and 840.degree. C., a GaAs nucleation layer of less than 200 angstroms and formed at a temperature between about 350.degree. C. and 450.degree. C., and a plurality of stacked groups of layers of InP, wherein adjacent InP layers are formed at different temperatures.