gebhart/patrepeval huggingface dataset:
Performance and Modeling of a Fully Packaged Micromachined Optical Microphone (2011)

A microelectromechanical systems (MEMS) optical microphone that measures the interference of light resulting from its passage through a diffraction grating and reflection from a vibrating diaphragm is described ( JASA, v. 122, no. 4, 2007). In the present embodiment, both the diffractive optical element and the sensing diaphragm are micromachined on silicon. Additional system components include a semiconductor laser, photodiodes, and required readout electronics. Advantages of this optical detection technique have been demonstrated with both omnidirectional microphones and biologically inspired directional microphones. In efforts to commercialize this technology for hearing aids and other applications, a goal has been set to achieve a microphone contained in a small surface-mount package (occupying 2 × 2 mm × 1 mm volume), with ultralow noise (20 dBA) and a broad frequency response (20 Hz-20 kHz). Such a microphone would be consistent in size with the smallest MEMS microphones available today but would have noise performance characteristics of professional-audio microphones significantly larger in size and more expensive to produce. This paper will present several unique challenges in our effort to develop the first surface-mount packaged optical MEMS microphone. The package must accommodate both optical and acoustical design considerations. Dynamic models used for simulating frequency response and noise spectra of fully packaged microphones are presented and compared with measurements performed on prototypes.
Studies on dihydropyridines. II. Synthesis of 4,7-dihydropyrazolo(3,4-b)pyridines with vasodilating and antihypertensive activities. (1987)

A series of 4-aryl-4, 7-dihydropyrazolo [3, 4-b] pyridine-5-carboxylate derivatives (72-149) was prepared and the compounds were tested for Ca-blocking activity in isolated guinea pig portal vein, antihypertensive activity in spontaneously hypertensive rats, and coronary vasodilating effect in isolated guinea pig heart. A number of derivatives had potent antihypertensive and coronary vasodilating activities. The structure-activity relationships of the series indicated that a 3-cyclopentyl or 3-cyclohexyl substituent and a hydrophobic 5-ester moiety with moderate bulkiness were effective for increasing the pharmacological potencies.
Nanoelectrode-Gated Detection of Individual Molecules with Potential for Rapid DNA Sequencing (2007)

A systematic nanoelectrode-gated electron-tunneling molecular-detection concept with potential for rapid DNA sequencing has recently been invented at Oak Ridge National Laboratory (ORNL). A DNA molecule is a polymer that typically contains four different types of nucleotide bases: adenine (A), thymine (T), guanine (G), and cytosine (C) on its phosphate-deoxyribose chain. According to the nanoelectrode-gated molecular-detection concept, it should be possible to obtain genetic sequence information by probing through a DNA molecule base by base at a nanometer scale, as if looking at a strip of movie film. The nanoscale reading of DNA sequences is envisioned to take place at a nanogap (gate) defined by a pair of nanoelectrode tips as a DNA molecule moves through the gate base by base. The rationale is that sample molecules, such as the four different nucleotide bases, each with a distinct chemical composition and structure, should produce a specific perturbation effect on the tunneling electron beam across the two nanoelectrode tips. A sample molecule could thus be detected when it enters the gate. This nanoscience-based approach could lead to a new DNA sequencing technology that could be thousands of times faster than the current technology (Sanger’s “dideoxy” protocol-based capillary electrophoresis systems). Both computational and experimental studies are underway at ORNL towards demonstrating this nanotechnology concept.
Ceramic temperature sensors for harsh environments (2005)

A ceramic thermocouple based on indium-tin-oxide (ITO) thin films is being developed to measure the surface temperature of gas turbine engine components employed in power and propulsion systems that operate at temperatures in excess of 1500/spl deg/C. By fabricating ITO elements with substantially different charge carrier concentrations, it was possible to construct a robust ceramic thermocouple. A thermoelectric power of 6.0 /spl mu/V//spl deg/C, over the temperature range 25-1250/spl deg/C, was realized for an unoptimized ITO ceramic thermocouple. The charge carrier concentration difference in the legs of the ITO thermocouple was established by r.f. sputtering in oxygen-rich and nitrogen-rich plasmas. SEM micrographs revealed that after high-temperature exposure, the surfaces of the nitrogen prepared ITO films exhibited a partially sintered microstructure with a contiguous network of ITO nanoparticles. Thermal cycling of ITO films in various oxygen partial pressures showed that the temperature coefficient of resistance was nearly independent of oxygen partial pressure at temperatures above 800/spl deg/C and eventually became independent of oxygen partial pressure after repeated thermal cycling below 800/spl deg/C. Based on these results, a versatile ceramic sensor system has been envisioned where a ceramic thermocouple and strain sensor can be combined to yield a multifunctional ceramic sensor array.
A critique on boron nitride nanotube reinforced metal matrix composites (2023)

Boron Nitride Nanotubes (BNNTs), a 1D nanomaterial with extraordinary mechanical properties, are structurally like carbon nanotubes. BNNTs possess superior thermal stability of ∼900 °C, higher resistance to oxidation at elevated temperatures, and enhanced neutron shielding capacity. These benefits open a wider processing window for manufacturing BNNT-reinforced metal matrix composites (MMC) and hold promise for several structural applications, including radiation shielding. This critique presents the current status, challenges, and future scientific possibilities of BNNT-reinforced MMC. Particular emphasis is laid on the progress made in this area regarding the synthesis, manufacturing, and characterization of BNNT-MMCs to date. The challenges associated with various processing techniques, including additive manufacturing (AM), are discussed in the fabrication of BNNT-MMCs. The experimental mechanics and structure-property relationship modeling are examined in detail to establish the utilization of BNNT-reinforced MMCs. Additionally, prospective research areas with a huge untapped potential for BNNT-MMCs are suggested. The scientific framework behind these methods’ chronological development is analyzed, and a pathway for subsequent advancement is projected. By providing a comprehensive overview, this critique aims to facilitate further progress in BNNT-reinforced MMCs.
Predicting Corrosion Under Disbonded Coating Using Modeling and Cathodic Protection Monitoring Coupon (2002)

Coating defects generally take the form of either exposed bare steel or a disbondment, where a gap is formed between a relatively intact coating and bare steel. Cathodic protection can be difficult to achieve and monitor in the disbonded regions depending on the type of coating and soil conditions. Furthermore, stress corrosion cracking occurs predominantly under disbonded coatings. This paper describes a numerical modeling approach to predict the potential and chemistry under disbonded coating. In addition, the use of a monitoring coupon to simulate pipeline disbondments is demonstrated.
Anisotropic Conductivity Tensor Imaging of <italic>In Vivo</italic> Canine Brain Using DT-MREIT (2016)

We present in vivo images of anisotropic electrical conductivity tensor distributions inside canine brains using diffusion tensor magnetic resonance electrical impedance tomography (DT-MREIT). The conductivity tensor is represented as a product of an ion mobility tensor and a scale factor of ion concentrations. Incorporating directional mobility information from water diffusion tensors, we developed a stable process to reconstruct anisotropic conductivity tensor images from measured magnetic flux density data using an MRI scanner. Devising a new image reconstruction algorithm, we reconstructed anisotropic conductivity tensor images of two canine brains with a pixel size of 1.25 mm. Though the reconstructed conductivity values matched well in general with those measured by using invasive probing methods, there were some discrepancies as well. The degree of white matter anisotropy was 2 to 4.5, which is smaller than previous findings of 5 to 10. The reconstructed conductivity value of the cerebrospinal fluid was about 1.3 S/m, which is smaller than previous measurements of about 1.8 S/m. Future studies of in vivo imaging experiments with disease models should follow this initial trial to validate clinical significance of DT-MREIT as a new diagnostic imaging modality. Applications in modeling and simulation studies of bioelectromagnetic phenomena including source imaging and electrical stimulation are also promising.
Multi-Color Arrays of III-Nitride Photonic Crystal Nanowire Lasers on a Single Chip (2013)

We have demonstrated a multi-color array of photonic crystal lasers on a single chip. By lithographically defining the geometrical properties of the photonic crystals we have achieved tuning from 376-435 nm using a single epitaxial growth.
A low-cost, radiation-hardened single-board computer for command and data handling (2016)

Los Alamos National Laboratory has designed and manufactured a single-board computer (SBC) for deployment in space-flight applications. The SBC is designed to meet the command- and data-handling requirements for missions requiring true space-grade radiation hardness and fault tolerance, exceeding those that are typical in CubeSat and SmallSat applications but at a substantially lower cost, lower power, and smaller form factor than encountered in the space-grade solution space available from the large aerospace manufacturers. The SBC leverages the MicroTCA standard, which makes it smaller than common 6U-sized solutions but still allows interoperability with a diverse ecosystem of commercial development equipment. The design uses QMLV or Class-S parts with total-ionizing-dose tolerance appropriate for deployment on long-term missions in MEO or GEO environments. The design uses a space-quality dual-core processor ASIC, a field-programmable gate array (FPGA), memories, and interfaces to meet the command- and data-handling requirements of medium-sized missions. Consuming only 5 W and measuring less than 7 inches × 6 inches, the design supports 9-gigabit/s class bidirectional SerDes links, 6 SpaceWire ports, redundant MIL-STD-1553B ports, 32 Mbytes of EDAC protected SRAM, 2 GBytes of nonvolatile memory, and supports 200 MFLOPS operation. Custom intellectual property (IP) has been developed for the FPGA to handle the interface to the nonvolatile memories and to provide error detection and correction for instrument boards elsewhere in the payload. The processor can run VxWorks™, RTEMS, or Linux. Cooling and mechanical hardness is achieved with a custom conduction-cooled frame that fits around the MicroTCA-form-factor printed circuit board.
Thermal analysis of blood undergoing laser photocoagulation (2001)

The temperature of blood undergoing laser-induced photocoagulation during long-pulse (10 ms) 532 nm irradiation was measured in a time- and spatially-resolved manner using a novel technique. This method is based on the change in reflectivity of a solid-liquid interface given a dynamically changing refractive index in the liquid phase. In our case, the temperature-dependent change in the refractive index of blood was utilized, and the reflectivity at a glass-blood interface was measured. Measurements were compared to predictions from a finite-element model incorporating the effects of time-dependent changes in the absorption coefficients of the blood, and phase changes representing coagulation and the liquid/vapor transition. Previous studies have linked the onset of blood coagulation to a sharp rise in the 532-nm reflectance of the blood. Based on the thermal measurements and the results of an Arrhenius analysis, we postulate that the reflectance rise is a combination of protein denaturation and red blood cell conformal changes.
Degradation of the Alzheimer's Amyloid β Peptide by Endothelin-converting Enzyme (2001)

Deposition of beta-amyloid (Abeta) peptides in the brain is an early and invariant feature of all forms of Alzheimer's disease. As with any secreted protein, the extracellular concentration of Abeta is determined not only by its production but also by its catabolism. A major focus of Alzheimer's research has been the elucidation of the mechanisms responsible for the generation of Abeta. Much less, however, is known about the mechanisms responsible for Abeta removal in the brain. In this report, we describe the identification of endothelin-converting enzyme-1 (ECE-1) as a novel Abeta-degrading enzyme. We show that treatment of endogenous ECE-expressing cell lines with the metalloprotease inhibitor phosphoramidon causes a 2-3-fold elevation in extracellular Abeta concentration that appears to be due to inhibition of intracellular Abeta degradation. Furthermore, we show that overexpression of ECE-1 in Chinese hamster ovary cells, which lack endogenous ECE activity, reduces extracellular Abeta concentration by up to 90% and that this effect is completely reversed by treatment of the cells with phosphoramidon. Finally, we show that recombinant soluble ECE-1 is capable of hydrolyzing synthetic Abeta40 and Abeta42 in vitro at multiple sites.
Perceptual codec and interaction aware playout algorithms and quality measurements for VoIP systems (2004)

To reduce the effect of network jitter, the playout algorithm for voice streams should correctly adjust the playout delay. Conventional playout algorithms were based on network delay only: they did not consider the perceptual quality, and were not aware the codec and interactive mode. Therefore, we present two novel approaches: codec aware adaptive playout (CAAP) algorithm and interactive aware adaptive playout (IAAP) algorithm, which intent to optimize the voice quality based on codec and interactive mode respectively. The performance of CAAP and IAAP are superior to the prior algorithms in our substantial evaluation. Since no objective mechanisms for measuring the speech quality of two-way communication exist, we also propose a new quality measurement for it.
[Molecular characterization of the hog cholera virus]. (1989)

The molecular biology of hog cholera virus (HCV) was studied. After reverse transcription of the viral RNA the cDNA was cloned in the expression vector lambda gt11. HCV clones were identified using antibodies as a probe. Partial sequencing of one HCV-derived cDNA clone revealed a high degree of homology to a portion of the bovine viral diarrhea virus (BVDV). One goal of these studies is the preparation of defined, effective and safe vaccines against pestiviruses.
Cell culture monitoring by impedance mapping using a multielectrode scanning impedance spectroscopy system (CellMap) (2008)

We report on the impedance mapping of in vitro cellular morphology by electrical impedance spectroscopy, using microelectrodes. A micro multielectrode system was designed, fabricated, assembled, tested and demonstrated for the monitoring of anchorage-dependent cell behavior and morphology. This system allowed continuous, label-free, quantitative monitoring and visualization of cell adhesion, spreading, proliferation and detachment due to cell cycle processes as well as cell-drug interaction, with spatio-temporal resolution. OvCa429 ovarian cancer cells were monitored in vitro over a period of 70 hours by inoculating the cell suspension directly on the multielectrode device. The phase angle of impedance was observed to develop a distinctive shape as a result of cell attachment and proliferation. The shape of the phase angle curve reverted back to the pre-attachment shape upon detachment of cells from the substrate, caused by the addition of trypsin to the cell culture medium. The impedance data of the cell culture were then successfully modeled as a multi-parametric equivalent circuit. The model incorporated both interfacial and cell-layer impedance parameters. Upon addition of trypsin, the cell-layer parameters showed a marked decline and were eventually eliminated from the multi-parametric model, confirming the correlation of the model to the electrode-cell-electrolyte system. These experiments demonstrate the applicability of the impedance mapping technique in visualizing and quantifying physiological changes in the cell layer due to cellular processes as well as the effect of external chemical stimulus on cells (cell-drug interaction).
Surfactant proteins B and C are both necessary for alveolar stability at end expiration in premature rabbits with respiratory distress syndrome (2008)

Modified natural surfactant preparations, used for treatment of respiratory distress syndrome in premature infants, contain phospholipids and the hydrophobic surfactant protein (SP)-B and SP-C. Herein, the individual and combined effects of SP-B and SP-C were evaluated in premature rabbit fetuses treated with airway instillation of surfactant and ventilated without positive end-expiratory pressure. Artificial surfactant preparations composed of synthetic phospholipids mixed with either 2% (wt/wt) of porcine SP-B, SP-C, or a synthetic poly-Leu analog of SP-C (SP-C33) did not stabilize the alveoli at the end of expiration, as measured by low lung gas volumes of approximately 5 ml/kg after 30 min of ventilation. However, treatment with phospholipids containing both SP-B and SP-C/SP-C33 approximately doubled lung gas volumes. Doubling the SP-C33 content did not affect lung gas volumes. The tidal volumes were similar in all groups receiving surfactant. This shows that SP-B and SP-C exert different physiological effects, since both proteins are needed to establish alveolar stability at end expiration in this animal model of respiratory distress syndrome, and that an optimal synthetic surfactant probably requires the presence of mimics of both SP-B and SP-C.
A Mechanism for Forming Large Fluorescent Organo-Silica Particles:  Potential Supports for Combinatorial Synthesis (2006)

The ability to track multiple compounds through a combinatorial synthesis on solid support particles can be a challenging exercise. A novel solution to this problem is to use the optical characteristics of each support particle to identify the biomolecule synthesized on its surface. To achieve this, we have synthesized a new class of porous, thiol-functionalized supports in a two-step process that used 3-mercaptopropyl trimethoxysilane as the monomer. The monomer was hydrolyzed and polymerized in an acidic solution, which formed an emulsion that was subsequently cross-linked with either ammonia (NH3) or methylamine (CH3NH2). The synthetic process and resulting organo-silica particles were characterized using silicon NMR, scanning electron microscopy techniques, and fluorescence microscopy. Furthermore, thin sections of the porous beads were successfully produced and analyzed via transmission electron microscopy. By controlling the reaction conditions during the synthesis, we achieved a variety of particle morphologies, including hollow particles, particles with macropores on the surface, and particles with a highly porous interior. The mechanism for forming and controlling the morphology of these particles is described here. Also described is the unique process of incorporating fluorescence dyes using combinatorial methods. This enabled the synthesis of a highly optically diverse population of particles, which could be produced over a small number of reactions. Flow cytometry was used to demonstrate the diversity of fluorescence signatures possessed by these encoded particles.
IC‐P‐051: Synthesis and Evaluation of Butyrylcholinesterase Ligands for Neuroimaging Alzheimer's Disease (2010)

Butyrylcholinesterase (BuChE) is a serine hydrolase enzyme that, along with acetylcholinesterase (AChE), catalyzes the hydrolysis of acetylcholine. Increased levels of BuChE are observed in Alzheimer's disease brain especially in neuritic plaques and neurofibrillary tangles, characteristic of the disease. This makes BuChE a suitable target for disease-specific neuroimaging. Cholinesterase ligands currently being investigated for imaging have the radioisotope in that part of the molecule that is the initial leaving group in the enzyme catalyzed hydrolysis. This may be, in part, responsible for poorly defined images with these ligands. We propose that BuChE-specific radiopharmaceuticals, having the radioisotope in the part of the molecule that forms the ligand-enzyme intermediate, can be used in PET and SPECT imaging to detect this enzyme in vivo, and thus the neuritic plaques and neurofibrillary tangles associated with AD. Imaging the AD plaques and tangles may provide an early diagnosis as well as a method for treatment monitoring. Piperidinols and pyrrolidinols were reacted with various acid chlorides and isocyanates to produce corresponding esters and carbamates, respectively. These compounds were evaluated using enzyme kinetics for their affinity towards both BuChE and AChE. BuChE-specific ligands were then transformed into intermediates suitable for incorporation of a radiolabel, either 123I for SPECT or 18F for PET imaging. Carrier free radiolabeled ligands were then administered to experimental animals and the distribution of BuChE in vivo determined. Several piperidinols and pyrrolidinols proved to be specific ligands for BuChE. These ligands were successfully transformed into both tin and tosylate intermediates. 123I was successfully incorporated into these molecules. Preliminary animal imaging indicated regional distribution of ligands. BuChE has been previously demonstrated to be involved in the pathology of AD. We have synthesized several BuChE-specific ligands that have been successfully radiolabeled. Preliminary animal imaging with these ligands indicated that there is regional distribution in the body and that these ligands are taken up into the brain. Further refinement of imaging methodology is underway. The imaging of BuChE in vivo may facilitate early diagnosis and treatment monitoring of AD.
Operation and analysis of low-voltage three-terminal avalanche photodiodes (2017)

We demonstrate a three-terminal waveguide avalanche photodiode detector (3TAPD) with -6V breakdown voltage, 18.6GHz 3dB bandwidth. Design, simulation of the device is discussed.
Quasi-species: the concept and the word (1995)

A type of dynamic genetic organization of a population in which individual genomes have a fleeting existence, and usually differ in one or more positions from the consensus or average sequence of the population, is known as a quasi-species. Quasi-species have been found among viruses with RNA genomes and originate as a result of the high mutation rates during RNA replication and reverse transcription, as well as in the competition among continuously arising variant genomes. Because the concept of the quasi-species is of fundamental importance to understand RNA viruses, in this brief chapter we address the origins of the idea, summarize its biological relevance by referring the reader to other articles and reviews, and discuss the adequacy of the term quasi-species.