gebhart/patrepeval huggingface dataset:
Single-mask, three-dimensional microfabrication of high-aspect-ratio structures in bulk silicon using reactive ion etching lag and sacrificial oxidation (2004)

This letter describes a simple method for three-dimensional microfabrication of complex, high-aspect-ratio structures with arbitrary surface height profiles in bulk silicon. The method relies on the exploitation of reactive ion etching lag to simultaneously define all features using a single lithographic masking step. Modulation of the mask pattern openings used to define the features results in etch depth variation across the pattern, which is then translated into surface height variation through removal of the superstructure above the etched floors. Utilization of a nonisotropic superstructure removal method based on sacrificial oxidation enables definition of high-aspect-ratio structures with vertical sidewalls and fine features. The utility of the approach is demonstrated in the fabrication of a sloping electrode structure for application in a hybrid micromirror device.
HIV-1 Infections During Vaccine Trials: Identifying New Peptides for Differential Diagnosis of HIV-1 Infections in the Face of Vaccine-generated Antibodies (2005)

Most of the HIV-1 vaccines under development contain multiple viral genes or proteins. As a result, many vaccinerecipients react positive in licensed HIV-1 detection assays. This will have negative impact on future efficacy trials of prophylactic HIV vaccines that require early detection of intercurrent HIV infections. It will also exclude all vaccinees from blood/plasma donations, and may contribute to other social harms. Therefore, it is important to design new strategies for vaccine trial participants that will clearly discriminate between vaccine-induced antibodies and true HIV-1 infection. We identified new HIV-1 epitopes that: 1) Do not contain important neutralizing or CTL epitopes, and can be omitted from future HIV vaccine candidates, 2) Recognized by antibodies from early HIV infected individuals, 3) Highly conserved among HIV-1 clades and subtypes. Using Phage Display libraries constructed from whole HIV-1 genome, combined with panning over antibodies from early seroconvertors, we identified new immunodominant epitopes, in the gp41 intracytoplasmic tail and in p6, which conform to the above criteria.
Quantitation of Chemical Warfare Agents Using the Direct Analysis in Real Time (DART) Technique (2009)

Direct analysis in real time (DART) is an ion source that permits rapid mass spectrometric detection of gases, liquids, and solids in open air under ambient conditions. It is a unique technology in the field of chemical weapons detectors in that it does not require a vapor pressure, does not require sample preparation, and is nondestructive to the original sample. While the DART technique has had success as a first line instrument of detection, there have been lingering doubts over the technique's quantitative reliability and reproducibility. Here, we demonstrate its capability to produce linear calibration curves (R(2) = 0.99 or better) for the nerve agents GA, GB, and VX as well as the blister agent HD. Independently prepared check standards measured against these curves typically have recovery errors less than 3%. We show the DART instrument response to be linear over roughly 3 orders of magnitude. Furthermore, this study shows that averaging as few as three measurements for each data point is sufficient to produce high quality calibration curves, thus reducing data collection time and providing quicker results.
Three-dimensional Reconstruction of the Microstructure of Human Acellular Nerve Allograft (2016)

The exact inner 3D microstructure of the human peripheral nerve has been a mystery for decades. Therefore, it has been difficult to solve several problems regarding peripheral nerve injury and repair. We used high-resolution X-ray computed microtomography (microCT) to scan a freeze-dried human acellular nerve allograft (hANA). The microCT images were then used to reconstruct a 3D digital model, which was used to print a 3D resin model of the nerve graft. The 3D digital model of the hANA allowed visualization of all planes. The magnified 3D resin model clearly showed the nerve bundles and basement membrane tubes of the hANA. Scanning electron microscopy (SEM) was used to analyse the microstructure of the hANA. Compared to the SEM images, the microCT image clearly demonstrated the microstructure of the hANA cross section at a resolution of up to 1.2 μm. The 3D digital model of the hANA facilitates a clear and easy understanding of peripheral nerve microstructure. Furthermore, the enlarged 3D resin model duplicates the unique inner structure of each individual hANA. This is a crucial step towards achieving 3D printing of a hANA or nerve that can be used as a nerve graft.
Tri-halide vapor-phase epitaxy of GaN using GaCl<sub>3</sub> on polar, semipolar, and nonpolar substrates (2016)

Abstract Homoepitaxial tri-halide vapor-phase epitaxy (THVPE) growth on polar, semipolar, and nonpolar bulk GaN substrates was demonstrated using GaCl 3 as the precursor. The influence of the surface orientation of the substrate on GaN growth by THVPE was compared with that observed for GaN grown by hydride vapor-phase epitaxy. The dependence of the GaN growth on the surface orientation of the substrate was confirmed; GaN could be grown on , , , , and but not on , , , or . This behavior was explained to be due to the changes in adsorption energy, the magnitudes of which were estimated by theoretical calculations.
Insights into Hemoglobin Assembly through in Vivo Mutagenesis of α-Hemoglobin Stabilizing Protein (2012)

α-Hemoglobin stabilizing protein (AHSP) is believed to facilitate adult Hemoglobin A assembly and protect against toxic free α-globin subunits. Recombinant AHSP binds multiple forms of free α-globin to stabilize their structures and inhibit precipitation. However, AHSP also stimulates autooxidation of αO(2) subunit and its rapid conversion to a partially unfolded bishistidyl hemichrome structure. To investigate these biochemical properties, we altered the evolutionarily conserved AHSP proline 30 in recombinantly expressed proteins and introduced identical mutations into the endogenous murine Ahsp gene. In vitro, the P30W AHSP variant bound oxygenated α chains with 30-fold increased affinity. Both P30W and P30A mutant proteins also caused decreased rates of αO(2) autooxidation as compared with wild-type AHSP. Despite these abnormalities, mice harboring P30A or P30W Ahsp mutations exhibited no detectable defects in erythropoiesis at steady state or during induced stresses. Further biochemical studies revealed that the AHSP P30A and P30W substitutions had minimal effects on AHSP interactions with ferric α subunits. Together, our findings indicate that the ability of AHSP to stabilize nascent α chain folding intermediates prior to hemin reduction and incorporation into adult Hemoglobin A is physiologically more important than AHSP interactions with ferrous αO(2) subunits.
Code-Division-Multiplexed Electrical Impedance Tomography Spectroscopy (2009)

Electrical impedance tomography uses multiple impedance measurements to image the internal conductivity of an object, such as the human body. Code-division multiplexing is proposed as a new method that can provide simultaneous impedance measurements of the multiple channels. Code division provides clear advantages of a wide frequency range at reduced cost and reduced complexity of sources. A potential drawback is the lack of perfectly orthogonal code sets. This caused an increase of 0.62% in root-mean-square spectral error when two codes were used to record two impedance channels simultaneously on a low-pass filter network. The method described provides images and spectra which are equivalent to the conventional time-multiplexed method, with increases in frequency resolution and measurement speed which may be of benefit in some applications of electrical impedance tomography spectroscopy.
Spatial and size-resolved electrostatic-directed deposition of nanoparticles on a field-generating substrate: theoretical and experimental analysis (2007)

We build on our prior work on electrostatically directed nanoparticle assembly on a field-generating substrate (Tsai et al 2005 Nanotechnology 16 1856–62). In this paper we develop a data set for particle size-resolved deposition, from which a Brownian dynamics model for the process can be evaluated. We have developed a trajectory model applied to positioning metal nanoparticles from the gas phase onto electrostatic patterns generated by biasing p–n junction substrates. Brownian motion and fluid convection of nanoparticles, as well as the interactions between the charged nanoparticles and the patterned substrate, including electrostatic force, image force and van der Waals force, are accounted for in the simulation. Using both experiment and simulation we have investigated the effects of the particle size, electric field intensity, and the convective flow on coverage selectivity. Coverage selectivity is most sensitive to electric field, which is controlled by the applied reverse bias voltage across the p–n junction. A non-dimensional analysis of the competition between the electrostatic and diffusion force is found to provide a means to collapse a wide range of process operating conditions and is an effective indicator of process performance.
Polymer and azo-dye composite: a photo-alignment layer for liquid crystals (2014)

In this article, we disclose a method to fabricate polymer-stabilised azo-dye photo alignment layers for liquid crystal. The idea includes the introduction of polymer network in the alignment layer, in optimal concentration, followed by two-step irradiation. The stabilised photo-alignment layer has been explored for different aspects of the display-related parameters, viz. anchoring energy, stability for various display-related environments as a function of concentration of monomer and irradiation, residual DC and voltage holding ratio. The composite photo-alignment layer offers well-suited parameters for the liquid crystal alignment and therefore could find application in a variety of modern photonic and display devices.
<title>High-gain GaAs photoconductive semiconductor switches for impulse sources</title> (1995)

A high peak power impulse pulser that is controlled with high gain, optically triggered GaAs Photoconductive Semiconductor Switches (PCSS) has been constructed and tested. The system has a short 50 (Omega) line that is charged to 100 kV and discharged through the switch when the switch is triggered with as little as 90 nJ of laser energy. We have demonstrated that the GaAs switches can be used to produce either a monocycle or a monopulse with a period or total duration of about 3 ns. For the monopulse, the voltage switched was above 100 kV, producing a peak power of about 48 MW to the 30 (Omega) load at a burst repetition rate of 1 kHz. The laser that is used is a small laser diode array whose output is delivered through a fiber to the switch. The current in the system has rise times of 430 ps and a pulse width of 1.4 ns when two laser diode arrays are used to trigger the switch. The small trigger energy and switch jitter are due to a high gain switching mechanism in GaAs.
Rapid free-breathing dynamic contrast-enhanced MRI using motion-resolved compressed sensing (2015)

Compressed sensing is a powerful rapid imaging approach for Magnetic Resonance Imaging (MRI) and has been applied to many clinical applications. In this work, we propose a new use of sparsity in addition to speed. In particular, we present a novel way of handling respiratory motion using compressed sensing for dynamic contrast-enhanced MRI. The proposed technique, called XD-GRASP (eXtra-Dimensional Golden-angle RAdial Sparse Parallel MRI), sorts the continuously acquired radial k-space data into undersampled contrast phases at multiple respiratory motion states using the self-navigation properties of radial imaging and employs a multidimensional compressed sensing reconstruction to exploit sparsity along both contrast-enhancement and respiratory motion dimensions. XD-GRASP improves image quality and also enables to track respiratory motion during contrast enhancement, which can potentially be of clinical value.
Extreme ultraviolet alignment and testing of a four-mirror ring field extreme ultraviolet optical system (2000)

Extreme ultraviolet (EUV) interferometry has been used to characterize and align a recently fabricated, 4× reduction, four-mirror, aspheric optical system designed for EUV lithography. This system is called the Engineering Test Stand Set-1 Optic. An EUV phase-shifting point diffraction interferometer constructed on an undulator beamline at the Advanced Light Source was used to perform high-accuracy wavefront measurements during several alignment iterations. For each iteration, the alignment algorithm used 35 wavefront measurements recorded across the 26-mm-wide image-side ring field. Adjustments were made to systematically reduce the root mean square wavefront error magnitude to approximately 1 nm, bringing the system to nearly diffraction-limited performance.
Potent bradykinin antagonists having medical potential (2005)

Bradykinin antagonist peptides have been developed during the past fourteen years into extremely potent and stable molecules that offer great potential for development into drugs for serious inflammation and cancers. The great need now is for financial support for these human studies.
Wide-angle point-to-point x-ray imaging with almost arbitrarily large angles of incidence (2008)

The paper describes a new scheme for wide-angle point-to-point x-ray imaging with almost arbitrarily large angles of incidence by a matched pair of spherically bent crystals to eliminate the astigmatism, which is a well-known imaging error of spherical mirrors. In addition to x rays, the scheme should be applicable to a very broad spectrum of the electromagnetic radiation, including microwaves, infrared and visible light, as well as UV and extreme UV radiation, if the crystals are replaced with appropriate spherical reflectors. The scheme may also be applicable to the imaging with ultrasound.
Robo-AO: autonomous and replicable laser-adaptive-optics and\nscience system\n (2012)

We have created a new autonomous laser-guide-star adaptive-optics (AO) instrument on the 60-inch (1.5-m) telescope at Palomar Observatory called Robo-AO. The instrument enables diffraction-limited resolution observing in the visible and near-infrared with the ability to observe well over one-hundred targets per night due to its fully robotic operation. Robo-AO is being used for AO surveys of targets numbering in the thousands, rapid AO imaging of transient events and long-term AO monitoring not feasible on large diameter telescope systems. We have taken advantage of cost-effective advances in deformable mirror and laser technology while engineering Robo-AO with the intention of cloning the system for other few-meter class telescopes around the world.
Injectable hyaluronic acid‐dextran hydrogels and effects of implantation in ferret vocal fold (2010)

Injectable hydrogels may potentially be used for augmentation/regeneration of the lamina propria of vocal fold tissue. In this study, hyaluronic acid (HA) and dextran were chemically modified and subsequently crosslinked via formation of hydrazone bonds in phosphate buffer. Swelling ratios, degradation, and compressive moduli of the resulting hydrogels were investigated. It was found that the properties of HA-dextran hydrogels were variable and the trend of variation could be correlated with the hydrogel composition. The biocompatibility of three injectable HA-dextran hydrogels with different crosslinking density was assessed in the vocal fold region using a ferret model. It was found that HA-dextran hydrogels implanted for three weeks stimulated mild foreign-body reactions. Distinct tissue-material interactions were also observed for hydrogels made from different formulations: the hydrogel with the lowest crosslinking density was completely degraded in vivo; while material residues were visible for other types of hydrogel injections, with or without cell penetration into the implantation depending on the hydrogel composition. The in vivo results suggest that the HA-dextran hydrogel matrices can be further developed for applications of vocal fold tissue restoration.
Using digital watermarks with image signatures to mitigate the threat of the copy attack (2003)

In some applications, the utility of an image watermarking system is greatly reduced if an attacker is able to extract a watermark from a marked image and re-embed it into an unmarked image. This threat is known as the copy attack. We develop an image signature scheme to be used with digital watermarks to create an image watermarking system that is more resistant to this attack. We describe the image signature algorithm in detail, and how it may be fused with a digital watermark. We then present preliminary results of our system using an image test set of highly correlated images.
Microfabricated Porous Silk Scaffolds for Vascularizing Engineered Tissues (2013)

There is critical clinical demand for tissue-engineered (TE), three-dimensional (3D) constructs for tissue repair and organ replacements. Current efforts toward this goal are prone to necrosis at the core of larger constructs because of limited oxygen and nutrient diffusion. Therefore, critically sized 3D TE constructs demand an immediate vascular system for sustained tissue function upon implantation. To address this challenge the goal of this project was to develop a strategy to incorporate microchannels into a porous silk TE scaffold that could be fabricated reproducibly using microfabrication and soft lithography. Silk is a suitable biopolymer material for this application because it is mechanically robust, biocompatible, slowly degrades <i>in vivo</i>, and has been used in a variety of TE constructs. We report the fabrication of a silk-based TE scaffold that contains an embedded network of porous microchannels. Enclosed porous microchannels support endothelial lumen formation, a critical step toward development of the vascular niche, while the porous scaffold surrounding the microchannels supports tissue formation, demonstrated using human mesenchymal stem cells. This approach for fabricating vascularized TE constructs is advantageous compared to previous systems, which lack porosity and biodegradability or degrade too rapidly to sustain tissue structure and function. The broader impact of this research will enable the systemic study and development of complex, critically-sized engineered tissues, from regenerative medicine to <i>in vitro</i> tissue models of disease states.
Thienothiopyran-2-sulfonamides: a novel class of water-soluble carbonic anhydrase inhibitors (1987)

An attempt to develop a water-soluble carbonic anhydrase inhibitor focused on exploring structure-activity relationships in the thienothiopyransulfonamide class. The strategy to influence water solubility while retaining carbonic anhydrase activity involved the introduction of a hydroxyl moiety and adjusting the oxidation state of the sulfur on the thiopyran portion of the molecule. Compounds 4 and 17 best fit the criteria of aqueous solubility and inhibitory potency vs. human carbonic anhydrase II and are candidates for evaluation as topically effective antiglaucoma agents.
Differential quadrature phase shift keying with close to homodyne performance based on multi-symbol phase estimation (2005)

We discuss an improved detection scheme for differential phase shift keying (DPSK) and differential quadrature phase shift keying (DQPSK), based on multi-symbol phase estimation (MSPE) through electrical signal processing. Using a recursive electrical signal processing algorithm, close to homodyne performance is obtained without a local oscillator at the receiver. In the presence of only Gaussian noise the proposed scheme yields a 0.5 dB and 1.8 dB sensitivity improvement over self-homodyne detection, for DPSK and DQPSK respectively. It furthermore improves robustness against impairments due to the influence of a finite laser linewidth and nonlinear phase noise. (7 pages)
Enhanced Post-Thaw Viability of Cryopreserved Cells by Oxygenated Perfluorocarbon or<i>Pluronic</i>® F-68 (1998)

Viability and growth following cryopreservation have been examined following (i) culture of Oryza sativa cv. Taipei 309 (Japonica rice) in medium overlaying oxygenated perfluorocarbon (PFC) liquid (Flutec PP6), and (ii) culture of two cvs. of Japonica rice (Taipei 309, Tarom), and Lolium multiflorum in media with Pluronic F-68 (0.01-0.2% w/v). The mean viability of cv. Taipei 309 rice cells following 4 days in medium overlaying oxygenated Flutec (0.45 +/- 0.07; n = 20) was significantly (P < 0.05) greater than control (0.35 +/- 0.08). Cell viability of cv. Tarom was increased by 400% (P < 0.001) with 0.1% (w/v) Pluronic F-68 in the recovery medium. Mean cell viability was also elevated 3-fold (P < 0.001) and 2-fold (P < 0.05) with 0.2% (w/v) and 0.01% (w/v) Pluronic, respectively. A 2-fold increase (P < 0.001) in viability occurred for Taipei 309 cells exposed to 0.01% (w/v) Pluronic F-68; that of Lolium cells was increased by 31% (P < 0.01) under similar conditions. Pluronic F-68 (0.01% w/v) also stimulated biomass, by 29-32%, in both cvs. Taipei 309 and Lolium at 30 days post-thawing.
Stationary digital breast tomosynthesis system with a multi-beam field emission x-ray source array (2008)

A stationary digital breast tomosynthesis (DBT) system using a carbon nanotube based multi-beam field emission x-ray (MBFEX) source has been designed. The purpose is to investigate the feasibility of reducing the total imaging time, simplifying the system design, and potentially improving the image quality comparing to the conventional DBT scanners. The MBFEX source consists of 25 individually programmable x-ray pixels which are evenly angular spaced covering a 48° field of view. The device acquires the projection images by electronically switching on and off the individual x-ray pixels without mechanical motion of either the x-ray source or the detector. The designs of the x-ray source and the imaging system are presented. Some preliminary results are discussed.