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 making composite nanoparticles comprises a) providing an amount of a polyelectrolyte having a charge, b) providing an amount of a counterion having a valence of at least 2, the counterion having a charge opposite the charge of the polyelectrolyte, c) combining the polyelectrolyte and the counterion in a solution such that the polyelectrolyte self-assembles to form a plurality of polymer aggregates, the plurality of polymer aggregates having an average diameter less than about 100 nm, d) adding a precursor to the solution, wherein the precursor has a charge opposite the charge of the polyelectrolyte, and e) allowing the precursor to infuse each polymer aggregate and polymerize so as to produce composite nanoparticles. The composite nanoparticles comprise a polymer aggregate containing at least one polyelectrolyte and at least one counterion and a polymer network crosslinked throughout the polymer aggregate. The polymer network may be inorganic, e.g silicon-containing.

Abstract: A method for detecting a target fluid in a fluid sample comprising a first fluid and the target fluid using photoacoustic spectroscopy (PAS), comprises a) providing a light source configured to introduce an optical signal having at least one wavelength into the fluid sample; b) modulating the optical signal at a desired modulation frequency such that the optical signal generates an acoustic signal in the fluid sample; c) measuring the acoustic signal in a resonant acoustic detector; and d) using the phase of the acoustic signal to detect the presence of the target fluid.

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: The present invention provides a sensor that includes an optical device as a support for a thin film formed by a matrix containing resonant nanoparticles. The nanoparticles may be optically coupled to the optical device by virtue of the geometry of placement of the thin film. Further, the nanoparticles are adapted to resonantly enhance the spectral signature of analytes located near the surfaces of the nanoparticles. Thus, via the nanoparticles, the optical device is addressable so as to detect a measurable property of a sample in contact with the sensor. The sensors include chemical sensors and thermal sensors. The optical devices include reflective devices and waveguide devices. Still further, the nanoparticles include solid metal particles and metal nanoshells. Yet further, the nanoparticles may be part of a nano-structure that further includes nanotubes.

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: 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: 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: 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.