gebhart/patrepeval huggingface dataset:
Wormhole liquid crystal display modes (2004)

Wormhole liquid crystal display modes are proposed. Micron-sized and randomly arranged holes on upper and lower electrodes are formed in order to deform a liquid crystal alignment. By optimizing cell thickness, the calculation of director profiles and transmittance based on Frank’s continuum theory and Jones matrix are carried out and the maximum transmittance is compared with experimental results. Good transmittance versus voltage characteristics was obtained regardless of the sign of the dielectric anisotropy. From optical microscopy, radial and spherical domains were found at the electrode holes. The position of these domains was randomly arranged and its shape was that of a half-cut droplet. Electro-optical response and viewing angle characteristics have also been evaluated.
Pulsed and DC charged PCSS based trigger generators (2009)

Prior to this research, we have developed high-gain, GaAs, photoconductive semiconductor switches (PCSSs) to trigger 50-300 kV high voltage switches (HVSs). We have demonstrated that PCSSs can trigger a variety of pulsed power switches operating at 50-300kV by locating the trigger generator directly at the HVS. This was demonstrated for two types of DC-charged trigatrons and two types of field distortion mid-plane switches, including a ?100 kVDC switch produced by the High Current Electronics Institute (HCEI) used in the linear transformer driver. The lowest rms jitter obtained from triggering a HVS with a PCSS was 100 ps from a 300 kV pulse-charged trigatron. PCSSs are the key component in these independently timed, fiber-optically controlled, low jitter trigger generators (TGs) for HVSs. TGs are critical sub-systems for reliable, efficient pulsed power facilities because they control the timing synchronization and amplitude variation of multiple pulse forming lines that combine to produce the total system output. Future facility scale pulsed power systems are even more dependent on triggering, as they consist of many more triggered HVSs and produce shaped-pulses by independent timing of the HVSs. As pulsed power systems become more complex, the complexity of the associated trigger systems also increases. One means to reduce this complexity is to allow the trigger system to be charged directly from the voltage appearing across the HVS. However, for slow or DC charged pulsed power systems this can be particularly challenging as the DC hold off of the PCSS dramatically declines. This paper presents results seeking to address HVS performance requirements over large operating ranges by triggering using a pulsed charged PCSS based TG. Switch operating conditions as low as 45% of self break were achieved. A DC charged PCSS based TG is also introduced and demonstrated over a 39 kV - 61 kV operating range. DC charged PCSS allow the TG to be directly charged from slow or DC charged pulsed power systems. GaAs PCSSs and neutron irradiated GaAs (n-GaAs) PCSSs were used to investigate the DC charged operation.
Point defects in Cu2ZnSnSe4 (CZTSe): Resonant X‐ray diffraction study of the low‐temperature order/disorder transition (Phys. Status Solidi B 9/2017) (2017)

Cu2ZnSnSe4 (CZTSe) gained interest as an earth abundant solar absorber material; however, thin films of CZTSe are known to have high levels of CuZn and ZnCu defects. The implication of this disorder is often debated, but it may contribute to the open circuit voltage deficit in CZTSe films, which has prevented these materials from becoming commercially viable. To explore this disorder, Schelhas et al. (article no. 1700156) have used resonant X-ray diffraction (REXD), a site and element specific probe of long-range order to determine the level of CuZn and ZnCu defects in CZTSe thin films annealed just below and quenched from just above the order/disorder transition temperature. The REXD technique utilizes the increase in scattering intensity of atoms near their resonant edge. The plot on the cover shows the idealized case of fully ordered Cu/Zn (black line – right structure), and fully disordered (red line – left structure). In this work, Schelhas et al. explore the Cu/Zn order in CZTSe thin films and comment on discrepancies between the REXD results and previous studies that employ NMR and optical spectroscopies. The authors present a structural model of the antiphase boundaries (pink plane) to explain previous observations in the literature and point to the importance of developing alternative approaches to CZTS processing.
Reconstitutable Nanoparticle Superlattices (2014)

Colloidal self-assembly predominantly results in lattices that are either: (1) fixed in the solid state and not amenable to additional modification, or (2) in solution, capable of dynamic adjustment, but difficult to transition to other environments. Accordingly, approaches to both dynamically adjust the interparticle spacing of nanoparticle superlattices and reversibly transfer superlattices between solution-phase and solid state environments are limited. In this manuscript, we report the reversible contraction and expansion of nanoparticles within immobilized monolayers, surface-assembled superlattices, and free-standing single crystal superlattices through dehydration and subsequent rehydration. Interestingly, DNA contraction upon dehydration occurs in a highly uniform manner, which allows access to spacings as small as 4.6 nm and as much as a 63% contraction in the volume of the lattice. This enables one to deliberately control interparticle spacings over a 4-46 nm range and to preserve solution-phase lattice symmetry in the solid state. This approach could be of use in the study of distance-dependent properties of nanoparticle superlattices and for long-term superlattice preservation.
High‐Yield Synthesis of Lipid Systems with Giant Rings (1992)

A high-temperature Glaser coupling reaction is the key to the efficient synthesis of lipids with “giant rings” as exemplified by reaction (a) (77% yield). Macrocyclic compounds are usually considered to have rings with twelve to twenty members; the term “giant rings” refers to compounds with even larger rings.
Clinical Gait Measures for Ambulatory Children with Cerebral Palsy (2015)

Purpose Valid and reliable measures of walking ability are needed to document the effectiveness of orthotic and therapeutic interventions for ambulatory children with cerebral palsy (CP). Selection of measures suited to evaluating children with CP can be informed by evidence of a measure's clinical utility and psychometric performance in the population of interest. The purpose of this review was to identify clinical measures that have been used to evaluate gait of children with CP, to review measures' evidence of psychometric testing, and to determine which measures are most appropriate for use with children with CP in a clinical setting. Materials and Methods PubMed, Web of Science, and PsycINFO databases were searched for measures with evidence of psychometric testing in children with CP. Results Eleven measures suitable for clinical administration were identified across 22 articles. Three measures had sufficient psychometric evidence to support clinical use in children with CP. Conclusions The 6-minute walk test, 10-meter walk test, and the Edinburgh Gait Scale are recommended for directly measuring walking capacity, speed, and rating walking form, respectively. Results of this review suggest that, although a range of measures exist for evaluating pediatric gait, additional work is needed to assess and document measures' psychometric properties in children with CP.
Effect of γ-Phase Stability on Local Deformation Energy of α-γ Duplex Stainless Steel (2017)

The effect of austenite (γ) phase stability in the local deformation region on the deformation energy of ferrite (α)-γ duplex stainless steel is investigated using tensile testing. The uniform deformation energy values of both the γ-stable and unstable duplex stainless steels are similar, while the local deformation energy of γ-stable duplex stainless steel is larger than that of γ-unstable duplex stainless steel. In γ-unstable duplex stainless steel, the difference in nano-indentation hardness between the α and transformed martensite (α') phases increases remarkably beneath the fractured surface. Low-voltage electron microscopy observations reveal that voids grow rapidly at the grain boundaries between the α and α' phases beneath the fractured surface, resulting in a decrease in the local deformation energy in γ-unstable duplex stainless steel.
WiMax system-in-package solutions based on LTCC- technology (2008)

This paper presents a highly integrated WiMax system-in-package (SiP) based on LTCC technology (low temperature co-fired ceramics). It comprises the complete passive and active RF frontend plus the transceiver RFIC for up- and down-conversion to base band. The overall size of such a smart package strongly depends on the applied technology and level of integration (multiband/multimode). The benefits on size reduction coming from advanced integration and assembly technologies are discussed and a very compact LTCC SiP with less than 50 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> size and SMT-compatible footprint is demonstrated. Top level measurements show full performance and thus fully validate the LTCC integration approach.
30.1 Single-Pair Automotive PHY Solutions from 10Mb/s to 10Gb/s and Beyond (2019)

Car communication networks are rapidly evolving from a collection of sub-MHz control busses to a high-performance data network for connecting sensors, processors, and actuators to enable autonomous driving [1]. A plurality of high-bandwidth nodes like cameras, displays, radars, and wireless transceivers, demand a network architecture revision and drive the need-for-speed on individual links [1], [2]. Harsh automotive requirements on emissions, robustness, and reliability apply [3]. Size and weight of cables are critical factors too. These challenges inspired a new class of single-pair physical layer solutions, with 100Mb/s currently in production, 1Gb/s ramping up soon, and new standards for 2.5-10Gb/s in development.
Paper II: Simulation of flow conditions in low-pressure flow reactors (Knudsen cells) using a Monte Carlo technique (1997)

A Monte Carlo program has been developed to simulate the gas dynamics inside flow reactors (Knudsen cells) specially adapted to study heterogeneous reactions. Because the reactors are operated under molecular flow conditions, the Monte Carlo technique can be applied to calculate trajectories of individual molecules considering only gas-wall collisions. Ensembles of trajectories are then used to generate synthetic kinetic data as a function of specific reactor geometries (surface-to-volume ratio, injector position, reactive-surface diameter, etc.) and analyzed to yield rate constants. The calculated rate constants thus obtained are useful in assessing the systematic error associated with a rate-constant determination and in the designing of future geometries of Knudsen cells.
Characterization of the dynamic shear properties of hyaline cartilage using high‐frequency dynamic MR elastography (2008)

This work evaluated the feasibility of dynamic MR Elastography (MRE) to quantify structural changes in bovine hyaline cartilage induced by selective enzymatic degradation. The ability of the technique to quantify the frequency-dependent response of normal cartilage to shear in the kilohertz range was also explored. Bovine cartilage plugs of 8 mm in diameter were used for this study. The shear stiffness (mu(s)) of each cartilage plug was measured before and after 16 hr of enzymatic treatments by dynamic MRE at 5000 Hz of shear excitation. Collagenase and trypsin were used to selectively affect the collagen and proteoglycans contents of the matrix. Additionally, normal cartilage plugs were tested by dynamic MRE at shear-excitations of 3000-7000 Hz. Measured micro(s) of cartilage plugs showed a significant decrease (-37%, P < 0.05) after collagenase treatment and a significant decrease (-28%, P < 0.05) after trypsin treatment. Furthermore, a near-linear increase (R(2) = 0.9141) in the speed of shear wave propagation with shear-excitation frequency was observed in cartilage, indicating that wave speed is dominated by viscoelastic effects. These experiments suggest that dynamic MRE can provide a sensitive quantitative tool to characterize the degradation process and viscoelastic behavior of cartilage.
A Class of Adaptively Regularised PNLMS Algorithms (2007)

A class of algorithms representing a robust variant of the proportionate normalised least-mean-square (PNLMS) algorithm is proposed. To achieve this, adaptive regularisation is introduced within the PNLMS update, with the analysis conducted for both individual and global regularisation factors. The update of the adaptive regularisation parameter is also made robust, to improve steady state performance and reduce computational complexity. The proposed algorithms are better suited not only for operation in nonstationary environments, but are also less sensitive to changes in the input dynamics and the choice of their parameters. Simulations in a sparse environment show the proposed class of algorithms offer enhanced performance and increased stability over the standard PNLMS.
What Is the Nearest Neighbor in High Dimensional Spaces (2000)

Nearest neighbor search in high dimensional spaces is an interesting and important problem which is relevant for a wide varietyofnovel database applications. As recentresults show, however, the problem is a very difficult one, not only with regards to the performance issue but also to the quality issue. In this paper, we discuss the quality issue and identify a new generalized notion of nearest neighbor search as the relevant problem in high dimensional space. In contrast to previous approaches, our new notion of nearest neighbor search does not treat all dimensions equally but uses a quality criterion to select relevant dimensions (projections) with respect to the given query. As an example for a useful quality criterion, we rate howwell the data is clustered around the query point within the selected projection. We then propose an efficient and effectivealgorithm to solve the generalized nearest neighbor problem. Our experiments based on a number of real and synthetic data sets sho...
Immortalization of human corneal endothelial cells using electroporation protocol optimized for human corneal endothelial and human retinal pigment epithelial cells (2000)

We describe for the first time a culture of SV40 transfected human corneal endothelial cells which recovered from crisis and can therefore be regarded as immortalized.
Reaction Kinetics of Gas–Solid Exchange Using Gas Phase Isotopic Oxygen Exchange (2016)

The oxygen transport kinetics of heterogeneous gas–solid exchange has been investigated on the basis of a two-step reaction mechanism, linking surface catalysis to solid-state self-diffusion, via gas phase isotopic oxygen exchange on the mixed ionic electronic conductor (MIEC) La0.6Sr0.4Co0.2Fe0.8O3–x (LSCF) and electronic conductor (La0.8Sr0.2)0.95MnO3±x (LSM). The catalytic activity of LSCF is higher than that of LSM toward the elementary step of oxygen dissociation, likely caused by a higher vacancy concentration. The apparent activation energy for surface exchange of LSCF is lower than values obtained from bulk characterization techniques. The diffusion coefficient (D) for LSM at different temperatures shows a huge deviation from literature values, and an alternate exchange mechanism has been proposed. The fast transport pathway is attributed to the substoichiometry of LSM in the near surface region. These results have significant implications for the improvement of the oxygen reduction reaction for the design of higher-performance materials and the importance and limitations of isotope exchange experimental design.
Experimental Evaluation of Surface Tension Criteria for Alignment Behavior of Liquid Crystals on Solid Surfaces (1995)

Experimental verification has been carried out the surface tension difference criteria for liquid crystal alignment on solid surfaces. Organic polymer films, with surface tension values controlled from 16.0 to 44.8 mN/m (which includes the surface tension of liquid crystal ZLI-1132) were examined. On films thick enough to avoid undesirable topological effects ( &gt;80 nm), the surface tension value at which the surface changed from a homogeneous to a homeotropic alignment was 31.2 mN/m, which is very close to the 31±0.5 mN/m value of ZLI-1132.
Radio Propagation Prediction Method Using Point Cloud Data Based on Hybrid of Ray-Tracing and Effective Roughness Model in Urban Environments (2018)

This paper proposes a radio propagation prediction method that uses point cloud data based on a hybrid of the ray-tracing (RT) method and an effective roughness (ER) model in urban environments for the fifth generation mobile communications system using high frequency bands. The proposed prediction method incorporates propagation characteristics that consider diffuse scattering from surface irregularities. The validity of the proposed method is confirmed by comparisons of measurement and prediction results gained from the proposed method and a conventional RT method based on power delay and angular profiles. From predictions based on the power delay and angular profiles, we find that the proposed method, assuming the roughness of σh=1mm, accurately predicts the propagation characteristics in the 20GHz band for urban line-of-sight environments. The prediction error for the delay spread is 2.1ns to 9.7ns in an urban environment.
Bioengineering Solutions for Manufacturing Challenges in CAR T Cells (2017)

The next generation of therapeutic products to be approved for the clinic is anticipated to be cell therapies, termed "living drugs" for their capacity to dynamically and temporally respond to changes during their production ex vivo and after their administration in vivo. Genetically engineered chimeric antigen receptor (CAR) T cells have rapidly developed into powerful tools to harness the power of immune system manipulation against cancer. Regulatory agencies are beginning to approve CAR T cell therapies due to their striking efficacy in treating some hematological malignancies. However, the engineering and manufacturing of such cells remains a challenge for widespread adoption of this technology. Bioengineering approaches including biomaterials, synthetic biology, metabolic engineering, process control and automation, and in vitro disease modeling could offer promising methods to overcome some of these challenges. Here, we describe the manufacturing process of CAR T cells, highlighting potential roles for bioengineers to partner with biologists and clinicians to advance the manufacture of these complex cellular products under rigorous regulatory and quality control.
InGaAs–GaAs Nanowire Avalanche Photodiodes Toward Single-Photon Detection in Free-Running Mode (2018)

Single-photon detection at near-infrared (NIR) wavelengths is critical for light detection and ranging (LiDAR) systems used in imaging technologies such as autonomous vehicle trackers and atmospheric remote sensing. Portable, high-performance LiDAR relies on silicon-based single-photon avalanche diodes (SPADs) because of their extremely low dark count rate (DCR) and afterpulsing probability, but their operation wavelengths are typically limited up to 905 nm. Although InGaAs-InP SPADs offer an alternative platform to extend the operation wavelengths to eye-safe ranges, their high DCR and afterpulsing severely limit their commercial applications. Here we propose a new separate absorption and multiplication avalanche photodiode (SAM-APD) platform composed of vertical InGaAs-GaAs nanowire arrays for single-photon detection. Among a total of 4400 nanowires constituting one photodiode, each avalanche event is confined in a single nanowire, which means that the avalanche volume and the number of filled traps can be drastically reduced in our approach. This leads to an extremely small afterpulsing probability compared with conventional InGaAs-based SPADs and enables operation in free-running mode. We show a DCR below 10 Hz, due to reduced fill factor, with photon count rates of 7.8 MHz and timing jitter less than 113 ps, which suggest that nanowire-based NIR focal plane arrays for single-photon detection can be designed without active quenching circuitry that severely restricts pixel density and portability in NIR commercial SPADs. Therefore, the proposed work based on vertical nanowires provides a new degree of freedom in designing avalanche photodetectors and could be a stepping stone for high-performance InGaAs SPADs.
Total Synthesis of Elisabethin A:  Intramolecular Diels−Alder Reaction under Biomimetic Conditions (2003)

We describe the first total synthesis of the marine diterpenoid elisabethin A. The synthesis uses (S)-hydroxy-2-methyl-propionate as the chiral starting material, which is elaborated into a dienyl-iodide and added to an aryl acetic acid ester via enolate alkylation. The hydroquinoid system is oxidized to the quinone which serves as the dienophile in a highly stereocontrolled intramolecular Diels-Alder addition. This IMDA reaction, which to our knowledge is the first one to employ a terminal (Z)-diene, proceeds under biomimetic conditions (water, ferrichloride as the oxidant, room temperature) with high yield and stereoselectivity. The Diels-Alder adduct is transformed into the natural product via a three-step sequence including selective hydrogenation, base-catalyzed epimerization of the cis- into the trans-decalin system and O-demethylation.
Nucleoside 3′-O-(2-Oxo-“Spiro”-4.4-Pentamethylene-1.3.2-Oxathiaphospholane)S: Monomers For Stereocontrolled Synthesis Of Oligo(Nucleoside Phosphorothioate/Phosphate)S (1998)

Abstract Attempts at synthesis of “chimeric” oligonucleotide constructs (PO/PS-Oligos) possessing phosphate and P-stereodefined phosphorothioate internucleotide linkages via combined phosphoramidite/oxathiaphospholane methods were unsuccessful. Therefore, novel monomers for oxathiaphospholane method, namely 5′-O-DMT-deoxyribonucleoside 3′-O(2-oxo-.spiro-4.4-pentamethylene-1.3.2-oxathiaphospholane)s, were prepared and used together with their diastereomerically pure 2-thio analogues for the stereocontrolled synthesis of “chimeric” oligonucleotide constructs (PO/PS-Oligos).
Surface modification of heteropoly acid/SPEEK membranes by polypyrrole with a sandwich structure for direct methanol fuel cells (2010)

A series of SPEEK/HPW/Ppy-n composite membranes with a sandwich structure were successfully prepared by surface modification with polypyrrole (Ppy) in order to stabilize phosphotungstic acid (HPW) in poly(ether ether ketone)s (SPEEKs) and reduce the methanol crossover. Ppy coatings with a large number of secondary ammonium groups (NH2+) interact with anions of HPW to decrease HPW leaching from the membrane. In addition, the hydrophobic Ppy layers allow for little methanol transport, which leads to a significant decline in methanol crossover with reasonable levels of proton conductivity. The properties of the membranes were investigated in detail by UV, SEM, ac impedance, and TGA. As observed, Ppy-modified membranes were better at immobilizing HPW and exhibited higher selectivities than previously reported SPEEK/HPW composite membranes. All the results indicate that the SPEEK/HPW/Ppy-n composite membranes are excellent candidates for direct methanol fuel cells.