Abstract: A method of treating or preventing infection at a surgical site comprising a bony defect and an implanted metal device is disclosed. Biodegradable microspheres are placed at the site and are capable of near-linear controlled release of an antibiotic agent for a predetermined period of time. The microspheres are configured to be large enough to avoid being phagocytosed and removed from the body, and small enough in diameter to not physically inhibit bone growth at said bony defect site. The microspheres are formed of polylactic-co-glycolic acid (PLGA), with or without polyethylene glycol (PEG), and sufficient antibiotic agent to produce bactericidal levels in body tissues. The microspheres exhibit near-linear delivery of the antibiotic agent for at least 4 weeks at levels exceeding the minimum inhibitory concentration (MIC) for organisms commonly found to be the cause of infections, and facilitate bone ingrowth or regrowth at the site.

Abstract: A method for forming carboxylate-alumoxane nanoparticles comprises subjecting a mixture comprising boehmite and carboxylic acid to mechanical shear. The method can be carried out at a temperature above ambient and preferably a temperature greater than 80° C., and can be carried out in the absence of a liquid phase.

Abstract: An improved system and method for communicating information on a transmission medium is disclosed. The disclosed system and method provide improved communications on the transmission medium in the presence of interference, which may take the form of uncorrelated interference from different services on neighboring transmission mediums. In one embodiment, the communications system includes a subscriber modem, a central office modem; and a communications channel coupled between the subscriber modem and the central office modem. The communications channel transports uplink signals from the subscriber modem to the central office modem, and downlink signals from the central office modem to the subscriber modem.

Abstract: System and methods for determining an optimized transmit spectra (spectral distributions of transmission power) for a set of communications channels that experience cross-talk among themselves and for transmitting data on the channels. The transmit spectra are preferably constructed so that largely contiguous frequency bands are allocated to each signaling direction (upstream/downstream) on each communications channel and/or to each channel in the set of channels. In one embodiment, each communications channel is restricted to a maximum time-averaged power. The method preferably includes steps of determining the channel transfer functions of the communications channel, determining interference characteristics of the channels, calculating substantially optimal transmit spectra for the communications channels, and redistributing the frequency bins so that they are contiguously grouped in each transmit spectra. The contiguous groupings allow wider frequency bands for signaling in the channel.

Abstract: This work discloses a unicast, end-to-end network performance measurement process which is capable of determining internal network losses, delays, and probability mass functions for these characteristics. The process is based on using groups of closely-spaced communications packets to determine the information necessary for inferring the performance characteristics of communications links internal to the network. Computationally efficient estimation algorithms are provided.

Abstract: The present invention provides nanoshell particles (“nanoshells”) for use in biosensing applications, along with their manner of making and methods of using the nanoshells for in vitro and in vivo detection of chemical and biological analytes, preferably by surface enhanced Raman light scattering. The preferred particles have a non-conducting core and a metal shell surrounding the core. For given core and shell materials, the ratio of the thickness (i.e., radius) of the core to the thickness of the metal shell is determinative of the wavelength of maximum absorbance of the particle. By controlling the relative core and shell thicknesses, biosensing metal nanoshells are fabricated which absorb light at any desired wavelength across the ultraviolet to infrared range of the electromagnetic spectrum. The surface of the particles are capable of inducing an enhanced SERS signal that is characteristic of an analyte of interest.

Abstract: Methods of reducing the water permeability of a water producing zone in a subterranean formation are provided. The methods basically comprise introducing a polymeric surfactant and an inert gas into the water producing zone to thereby form a water permeability reducing foam therein. The polymeric surfactant has the property of facilitating the formation of the foam and the additional property of stabilizing the foam in the presence of flowing formation water.

Abstract: This process results in directed electroless plating of the metal to form discrete metal structures over the entire surface. Because the surface is pre-patterned with passivated regions inert to metal deposition, the metal is directed only to the unstamped regions. This allows the formation of unconnected metal structures without any chemical etching steps. These metallic arrays are varied in size, separation and shape by using gratings of different periodicities and blaze angles as the stamp templates. A variety of well-defined geometric patterns have been fabricated and imaged using scanning probe, scanning electron, and optical microscopies.

Abstract: Methods and apparatus for providing nanoparticles having reduced symmetry are disclosed. One embodiment of a preferred method for producing such nanoparticles includes functionalization of a nanoparticle core, partial chemical passivation or masking of the nanoparticle surface, and nucleation and deposition of colloidal particles to selectively coat a specific section of the nanostructure surface with a conducting material.

Abstract: A method for purifying a suspension containing colloid-seeded nanoparticles and excess colloids is provided that includes adding to the suspension a filter aid comprising a salt. The method further includes filtering the suspension with a filter of a pore size intermediate between the average colloid-seeded nanoparticle size and the average excess colloid size, so as to form a retentate that includes the majority of the colloid-seeded nanoparticles and a filtrate that includes the majority of the excess colloids. Still further, the method includes collecting the retentate. The method may be incorporated into a method of making metallized nanoparticles, such as nanoshells, by reduction of metal ions onto the purified colloid-seed nanoparticles so as to form the metallized nanoparticles.

Abstract: A polymer network formed by crosslinking poly(propylene fumarate) with a fumarate derivative. The fumarate derivative is one in which the PPF is soluble, is preferably an alkyl fumarate, and is more preferably selected from the group consisting of diethyl fumarate, dimethyl fumarate, methyl ethyl fumarate, diisopropyl fumarate, and dibutyl fumarate. The network can be formed by photo-crosslinking and can be porous. In some embodiments, the poly(propylene fumarate) and the fumarate derivative are each present in an amount effective to produce a polymeric network useful for in vivo applications. The network can be formed from an injectable, in situ crosslinkable composite formulation, or can be prefabricated from a crosslinkable composite formulation such as stereolithography, rapid prototyping, injection molding, and extrusion molding.

Abstract: Composite particles containing metallic shell layers are provided. The particles may include a coating layer, such as of a protective or electrically non-conducting material, over an outermost metallic shell layer. The particle preferably has a plasmon resonance associated with at least one metallic shell layer. The coating layer preferably imparts improved thermal stability to the plasmon resonance. Further, the present invention relates to particles that include at least two metallic shell layers, separated by a coating layer. The addition of a second metallic shell layer preferably allows the plasmon resonance of the shell layer to be more red-shifted with respect to a colloidal particle of the metal that the plasmon resonance of a particle of the same size but with only a single metallic shell.

Abstract: Nonlinear control algorithms to compensate for kinematic error in harmonic drives provide a solid basis to improve their performance of harmonic drives in precision positioning applications. The present closed loop control algorithms compensate for kinematic error irrespective of its form in both set-point and trajectory tracking applications.

Abstract: A thermally sensitive polymer-particle composite that absorbs electromagnetic radiation, and uses the absorbed energy to trigger the delivery of a chemical is disclosed. Metal nanoshells are nanoparticulate materials that are suitable for use in the present composites and can be made according to a process that includes optically tuning or tailoring their maximum optical absorption to any desired wavelength primarily by altering the ratio of the core diameter to the shell thickness. Preferred nanoshells are selected that strongly absorb light in the near-infrared and thus produce heat. These nanoshells are combined with a temperature-sensitive material to provide an implantable or injectable material for modulated drug delivery via external exposure to near-IR light. This invention provides a means to improve the quality of life for persons requiring multiple injections of a drug, such as diabetes mellitus patients.

Abstract: A composition of matter, comprising: a chemically functionalized carboxylate-alumoxane that is functionalized with a chemically reactive substituent, and a reactive compound, wherein the chemically reactive substituent reacts with the reactive compound so as to link the carboxylate-alumoxane to the reactive compound and form a polymer matrix. The functional groups on the carboxylate-alumoxane can vary depending on the desired properties of the matrix. Also, the composition of matter may comprise a cross-linked matrix in which the cross-linked components consist of functionalized alumoxanes.

Abstract: High molecular weight linear poly(propylene fumarate) having a relatively low polydispersity index by utilizing a relatively pure intermediate and a method for making same. Fumaryl chloride and propylene glycol are reacted in the presence of potassium carbonate. The potassium carbonate present in the reaction solution prevents the acid by-product from catalyzing reactions at the fumarate double bond. The bis(propyl fumarate) produced according to this technique can be transesterified using conventional processing steps to yield P(PF). The P(PF) produced from bis(propyl fumarate) produced according to the present method has a higher molecular weight and is purer than P(PF) produced using previously known techniques.

Abstract: A non-toxic contrast agent for enhancing contrast in in vivo magnetic resonance measurements, comprised of a water-soluble, stable paramagnetic fullerene that is free of paramagnetic metal species. A preferred contrast agent is a fullerol having at least one unpaired electron.

Abstract: The present invention is for particulate compositions and methods for producing them that can absorb or scatter electromagnetic radiation. The particles are homogeneous in size and are comprised of a nonconducting inner layer that is surrounded by an electrically conducting material. The ratio of the thickness of the nonconducting layer to the thickness of the outer conducting shell is determinative of the wavelength of maximum absorbance or scattering of the particle. Unique solution phase methods for synthesizing the particles involve linking clusters of the conducting atoms, ions, or molecules to the nonconducting inner layer by linear molecules. This step can be followed by growth of the metal onto the clusters to form a coherent conducting shell that encapsulates the core.

Abstract: Heterogeneous solid supra-molecular alkylalumoxanes. A supra-molecular architecture of a nano-particle foundation on which an alkylalumoxane is built. Supra-molecular alkylalumoxanes comprise (a) an aluminum-oxide nanoparticle, (b) a linkage unit, and (c) an alkylalumoxane. Supra-molecular alkylalumoxanes are prepared by the reaction of a chemically modified aluminum-oxygen nanoparticle with either a pre-formed alkylalumoxane or an alkylaluminum compound, with subsequent hydrolysis or reaction with other alkylalumoxane yielding reagents. The supra-molecular alkylalumoxanes are active as catalysts for the polymerization of organic monomers and as co-catalysts with transition metal components for the polymerization of olefins.

Abstract: A system and method for determining transmission characteristics for a communications channel and for transmitting data on the communications channel. In one embodiment, the method starts by determining the channel's transfer function and determining interference characteristics for the channel. The interference characteristics preferably include transfer functions describing the channel's susceptibility to cross talk from neighboring channels. The channel transfer function and the interference characteristics are then examined and a transmit spectrum (or power spectral density function) is constructed for the channel. The transmit spectrum preferably uses orthogonal separation of upstream and downstream communications to increase channel capacity.