gebhart/patrepeval huggingface dataset:
Assessing the Electronic Structure of TaVOx and Its Electrochromic Performance in Combination with LiPSON (2023)

In this study, radio-frequency sputtered tantalum vanadium oxide (TaVOx) films are investigated as a promising material for the ion storage layer in an electrochromic device. Using spectroelectrochemical measurements by cyclic voltammetry, the electrochromic switching properties of the material are presented. The intercalation and deintercalation mechanisms of Li+ ions into TaVOx thin films have been studied by X-ray photoelectron spectroscopy. To obtain information about the composition and electronic structure of the material, films with different degrees of intercalation levels of Li+ ions are studied. The results clarify which species are involved in the electrochromic mechanism. In order to be able to evaluate the stability of electrochemically treated samples, films in the final deintercalated state are also analyzed. It is shown that only vanadium is actively involved in the investigated redox reaction. Finally, TaVOx is integrated with the solid-state electrolyte lithium phosphorus sulfuric oxynitride into a model electrochromic switching cell. Chronoamperometry shows a stable charge transfer of about 27 mC cm–2 combined with suitable values for optical transmittance of more than 70% (at 550 nm). Based on the high stability in terms of charge density and suitable color neutrality, we confirm the general suitability of this material combination for use in electrochromic applications.
Umbilical Cord Blood Research: Current and Future Perspectives (2007)

Umbilical cord blood (UCB) banking has become a new obstetrical trend. It offers expectant parents a biological insurance policy that can be used in the event of a child or family member's life-threatening illness and puts patients in a position of control over their own treatment options. However, its graduation to conventional therapy in the clinical realm relies on breakthrough research that will prove its efficacy for a range of ailments. Expanding the multipotent cells found within the mononuclear fraction of UCB so that adequate dosing can be achieved, effectively expanding desired cells ex vivo, establishing its safety and limitations in HLA-mismatched recipients, defining its mechanisms of action, and proving its utility in a wide variety of both rare and common illnesses and diseases are a few of the challenges left to tackle. Nevertheless, the field is moving fast and new UCB-based therapies are on the horizon.
10 nm gap bowtie plasmonic apertures fabricated by modified lift-off process (2016)

Bowtie plasmonic apertures, with gap sizes down to 11 nm and silver film thickness of up to 150 nm (aspect ratio 14:1), were fabricated on a silicon nitride membrane. Transmission spectra feature the aperture resonances ranging from 470 to 687 nm, with quality factors around 10. The mode area of the smallest gap aperture is estimated to be as small as 0.002 (k/n)[superscript 2] using numerical modeling. Importantly, our fabrication technique, based on an e-beam lithography and a lift-off process, is scalable which allows fabrication of many devices in parallel over a relatively large area. We believe that the devices demonstrated in this work will find application in studying and engineering light-matter interactions.
<em>In-Operando</em> Evaluation of Solid Oxide Fuel Cell (SOFC) Cathodes for Enhanced Oxygen Reduction Reaction (ORR) Activity and Durability (2018)

Through this project we developed a new in-operando 18O-isotope exchange technique, and determined the oxygen reduction reaction (ORR) kinetics and mechanisms in various solid oxide fuel cell (SOFC) cathodes under real operating conditions of applied voltage. We were able to measure and determine oxygen surface exchange coefficients of labeled oxygen with La0.8Sr0.2MnO3 (LSM), La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and other cathode material samples with varying compositions. We related the cell polarization conditions to the surface exchange process and surface exchange coefficient, and suggested a model to describe this relation. Our findings imply that LSCF keeps its higher exchange rate performance over LSM under real operating conditions. Changing the A-site cation ratio in LSM can enhance its performance, especially under cathodic polarizations larger than -400mV. Cathode powder composites of LSM and LSCF with YSZ and GDC show lower exchange coefficient values under applied polarization compared to the single constituent powder samples, probably due to limited contact between the powder particles. Using our model and basic electrochemical properties of the cathode materials we are able to successfully predict the exchange kinetic properties of SOFC cathode material under real operating conditions of applied voltage / current from surface exchange coefficients obtained in the absence of an applied bias.
Fast laser-scanning microscopy with single- and multi-photon excitation for functional imaging of living nerve cells (2004)

Functional neuro-imaging is often limited by the spatio-temporal resolution of available imaging systems. The goal of this project is fast multi-site imaging of nerve cells in intact mammalian brain tissue. We will review fundamentals of fast laser-scanning microscopy employing acousto-optic beam steering and show examples of neuro-imaging applications. Specifically, we will discuss the significance and technical challenges of extending this imaging approach from single- to multi-photon excitation. We will present the current development status of a new imaging system implementing acousto-optical scanning of ultra-fast laser pulses.
Structural basis for ion selectivity in potassium-selective channelrhodopsins (2022)

SUMMARY The KCR channelrhodopsins are recently-discovered light-gated ion channels with high K + selectivity, a property that has attracted broad attention among biologists– due to intense interest in creating novel inhibitory tools for optogenetics leveraging this K + selectivity, and due to the mystery of how this selectivity is achieved in the first place. Indeed, the molecular and structural mechanism for K + selectivity in KCRs has remained especially puzzling since these 7-transmembrane retinal-binding proteins completely lack structural similarity with known K + channels, which generally coordinate K + in a precisely symmetric conduction pathway formed by a tight interface among multiple small monomeric channel subunits (presumably not an accessible mechanism for the large KCR rhodopsin proteins). Here we present the cryo-electron microscopy structures of two KCRs from Hyphochytrium catenoides with distinct spectral properties for light absorption and channel actuation, Hc KCR1, and Hc KCR2, at resolutions of 2.6 and 2.5 Å, respectively. Structural comparison revealed first an unusually-shaped retinal binding pocket which induces rotation of the retinal in Hc KCR2, explaining the large spectral difference between Hc KCR1 and 2. Next, our combined structural, electrophysiological, computational, and spectroscopic analyses revealed a new solution to the challenging problem of K + -selective transport. KCRs indeed do not exhibit the canonical tetrameric K + selectivity filter that specifically coordinates dehydrated K + ; instead, single KCR monomers form a size exclusion filter using aromatic residues at the extracellular side of the pore which inhibits passage of bulky hydrated ions. This unique feature allows KCRs to function as K + channels under relevant physiological conditions, providing not only a novel mechanism for achieving high K + permeability ratios in biological ion channels, but also a framework for designing the next generation of inhibitory optogenetic tools. In Brief The first structures of K + -selective channelrhodopsins ( Hc KCR1 and 2) are determined, revealing a K + selectivity mechanism distinctly different from canonical K + channels. Highlights The cryo-EM structures of K + -selective channelrhodopsins, Hc KCR1 and 2, in nanodisc Conditions under which naturally-occurring microbial rhodopsins have a 6-s- cis retinal Identification of key residues for high K + permeability ratios The unique K + selectivity mechanism of KCRs
Investigation of phase distortion in the synthesis of head-related transfer functions (1992)

Synthesizing over headphones the free-field to ear-canal transfer functions, or head-related transfer functions (HRTFs), of the human auditory system poses several difficulties from the standpoint of digital signal processing. Since the order of the HRTF is unknown, it is necessary to assume a particular value when estimating the HRTF from responses obtained in an anechoic chamber. Additionally, while standard filter designs minimize the squared error between the desired and designed response, applications such as HRTF synthesis are likely to require error metrics that are sensitive to disparities between the log magnitude response of each system. A new design algorithm is proposed that is based on a logarithmic distortion metric and it is shown how this algorithm can be used to obtain minimum phase, low-order pole-zero approximations to HRTFs. Psychophysical results characterizing audibility sensitivity to such HRTF approximation errors are presented in order to establish an audible limit for the distortion in such designs. These results are compared with similar experimental results for the widely used least-squares metric. [Research supported by a grant from the NIDCD of the National Institute of Health.]
What are the consequences of freezing the anomeric effect in nucleosides? (2008)

The consequences of freezing the orientation of the oxygen's lone pair orbitals--which determines whether the anomeric effect is operative or not--were studied theoretically and experimentally in two oxobicyclo-[3.1.0]hexane nucleosides (1 and 2). The results showed significant differences in the properties of these molecules, which correlated with the magnitude of the n2 --> sigma * delocalization.
Topics in Modeling and Control of Spatially Distributed Systems (2014)

This dissertation consists of three parts centered around the topic of spatially distributed systems.The first part treats a specific spatially distributed system, the so-called Rijke tube, an experiment illustrating the unstable interplay of heat exchange and gas dynamics. The experiment is described in detail and it is demonstrated how closed-loop system identification tools can be applied to obtain a transfer function model, before a spatially distributed model is developed and analyzed. The model in its most idealized form can be described in the frequency domain by a matrix of non-rational transfer functions, which facilitates analysis with classical methods such as the root locus.The second part considers the following problem: for a given plant and cost function, could there be a finite-length periodic trajectory that achieves better performance than the optimal steady state? Termed optimal periodic control (OPC), this problem has received attention over several decades, however most available methods employ state-space based methods and hence scale very badly with plant dimension. Here, the problem is approached from a frequency-domain perspective, and methods whose complexity is independent of system dimension are developed by recasting the OPC problem for linear plants with certain memoryless polynomial nonlinearities as the problem of minimizing a polynomial.Finally, the third part extends results for a special class within spatially distributed systems, that of spatially invariant systems, from systems defined on L_2 (square-integrable) spaces to systems whose state space is an inner-product Sobolev space as they arise when considering systems of higher temporal order. It is shown how standard results on exponential stability, stabilizability and LQ control can be generalized by carefully keeping track of spatial frequency weighting functions related to the Sobolev inner products, and simple recipes for doing so are given.
Improved measurement of grain–wall contact forces in granular beds using wavelength scanning interferometry (2005)

We describe a wholefield optical technique based on a wavelength scanning Fizeau interferometer for measuring the contact forces between a granular bed and a transparent substrate. The substrate material is polymethyl methacrylate (PMMA), aluminium-coated on the internal surface, and changes to the interference pattern formed by reflection from the two surfaces allow the displacement field induced by the contacting grains to be visualized. Quantitative displacement data are obtained by phase shifting the interference pattern using a tunable laser. In order to avoid miscalibration errors associated with the non-linearities of the laser source, a Newton–Raphson iteration scheme is employed to search for the correct PZT voltage required for the linear phase-shifting steps. A new 31-frame phase-shifting algorithm based on the Chebyshev window function was designed to deal with the problems of residual miscalibration and higher harmonics created by multiple reflections within the substrate. The resulting noise in the measurements is below 1 nm, and the repeatability of the load–displacement relationship was found to be approximately 10 nm.
Viral Hepatitis in Colombia: A Study of the “Hepatitis of the Sierra Nevada De Santa Marta” (1985)

The prevalences of hepatitis B virus (HBV), hepatitis delta virus and hepatitis A virus infections were studied in two regions of Colombia. In Bogota, 10 of 53 patients with acute hepatitis were HBsAg positive and three of these were hepatitis D antigen positive. Hepatitis A virus was the major cause of acute hepatitis in this group. In 366 healthy controls from Bogota, 1.6% were HBsAg positive and 7.1% had at least one marker of HBV infection. In northern Colombia, individuals from three villages with outbreaks of the fulminant "hepatitis of the Sierra Nevada de Santa Marta" were tested. The prevalences of HBsAg (1.8 to 23%) and HBV infection (35 to 93%) were generally high and varied from village to village; 60% of the HBsAg carriers in one village were positive for antibody to hepatitis D antigen, and two individuals in the outbreak area had circulating hepatitis D antigen. The findings suggest that HBV and the associated hepatitis delta virus are etiologic factors in the "hepatitis of the Sierra Nevada de Santa Marta."
Influence of nucleants on the formation of shear-induced structures in polypropylene (2002)

The interaction between the type of nucleating agent and base polymer was investigated for a combination of three commercial nucleants and polypropylenes each. Both the crystallisation behavior under DSC conditions and the mechanical and optical properties were determined for all materials. For both the influences of the nucleant and of the base polymer, the present study has provided qualitative indications as to the triggered crystal morphology and shear-induced superstructure. Especially the latter can be related to the differences between optical and mechanical effects of the nucleation process.
Replication of restless legs syndrome loci in three European populations (2009)

Our study shows that variants in these three loci confer consistent disease risks in patients of European descent. Among the known loci, BTBD9 seems to be the most consistent in its effect on RLS across populations and is also most independent of familial clustering.
miRNAs in precancerous lesions of the gastrointestinal tract (2011)

In spite of the well-established understanding of the phenotypic lesions occurring in the shift from native epithelia to invasive (adeno) carcinoma, the molecular typing of the precancerous changes in the gastrointestinal tract remains unreliable. In recent years, no biomarkers have aroused as much interest as the miRNAs, a class of non-coding RNA molecules that function as endogenous silencers of numerous target genes. Aberrant miRNA expression is a hallmark of human disease, including cancer. Unlike most mRNAs, miRNAs are both long-living in vivo and very stable in vitro. Such characteristics allow their testing in paraffin-embedded tissue samples, which is essential in the biological profiling of small (phenotypically characterized) preneoplastic lesions of the gastrointestinal tract (as well as in other fields of human pathology). The upcoming challenge lies in the reliable identification of disease-specific targets of dysregulated miRNAs, to enable miRNA testing in the clinical management of the secondary prevention of gastrointestinal cancer.
Fundamental Statistical Limitations to X-Ray Quantum Detection (1986)

A model for the detective quantum efficiency (DQE) of a screen-film system has recently been developed 1,2 which includes all the principle inefficiencies of both screen and film. Subsequent comparison of this model with detailed practical measurements has confirmed its power of prediction. 3
Comparison of the Effects of Titania and Tantalum Oxide Nucleating Agents on the Crystallization of Li 2 O · Al 2 O 3 · 6SiO 2 Glasses (1989)

The crystallization mechanism in Li 2 O‐Al 2 O 3 ‐SiO 2 (1 : 1 : 6) glasses was investigated with TiO 2 or Ta 2 O 5 as nucleation agents, by differential thermal analysis, X‐ray diffractometry, and transmission electron microscopy. Phase separation occurred prior to crystallization in all of the glasses studied. Both TiO 2 and Ta 2 O 5 additives promoted nucleation and crystal growth in the bulk glasses by causing the precipitation of crystalline precursor phases dispersed within phaseseparated glass, which acted as heterogeneous nucleation sites for β‐quartz(ss) (solid solution) formation. Upon reheating glasses with Ta 2 O 5 as the nucleating agent, phase separation occurred, followed by LiTa 3 O 8 and Ta 2 O 5 nucleation and limited growth as the first‐formed crystalline phases, and then crystallization of β‐quartz structured solid solution, which nucleated and grew from the LiTa 3 O 8 /Ta 2 O 5 crystallites. Tantalum was rejected from the growing β‐quartz(ss), further precipitating Ta 2 O 5 . Eventually, β‐quartz(ss) transformed to β‐spodumene(ss) with increasing temperature. Upon reheating glasses nucleated with TiO 2 additive, they initially phase separated, followed by the formation of crystalline precursors, in turn followed by the near simultaneous crystallization of β‐quartz(ss) and β‐spodumene(ss), transforming to solely β‐spodumene(ss) with increasing temperature [Key words: glass, titania, tantalum oxide, nucleation, crystallization.]
Large-scale, surface tension assisted Ball-in-Pit self population for chip-to-chip passive alignment (2013)

The Ball-in-Pit passive layer-to-layer self-alignment technique has previously been shown to achieve submicron alignment between stacked chips. This structure sandwiches a precision sapphire ball between inverse pyramidal pits etched on the faces of chips to be aligned. In this work, we present a universal and low-cost fluidic approach to self-populate balls into a large-scale array of etched pits. This population technique could be used to populate pits on a wafer, a multichip interposer, or individual chips.
Temperature measurement in the Intel(R) CoreTM Duo Processor (2007)

Modern CPUs with increasing core frequency and power are rapidly reaching a point where the CPU frequency and performance are limited by the amount of heat that can be extracted by the cooling technology. In mobile environment, this issue is becoming more apparent, as form factors become thinner and lighter. Often, mobile platforms trade CPU performance in order to reduce power and manage thermals. This enables the delivery of high performance computing together with improved ergonomics by lowering skin temperature and reducing fan acoustic noise. Most of available high performance CPUs provide thermal sensor on the die to allow thermal management, typically in the form of analog thermal diode. Operating system algorithms and platform embedded controllers read the temperature and control the processor power. Improved thermal sensors directly translate into better system performance, reliability and ergonomics. In this paper we will introduce the new Intel CoreTM Duo processor temperature sensing capability and present performance benefits measurements and results.
Charge Trapping in Intergrain Regions of Pentacene Thin Film Transistors (2008)

Abstract A scanning Kelvin probe microscopy (SKPM) study of the surface potential of vacuum sublimed pentacene transistors under bias stress and its correlation with the film morphology is presented. While for thicker films there are some trapping centers inhomogeneously distributed over the film, as previously reported by other authors, by decreasing the film thickness the effect of thin intergrain regions (IGRs) becomes clear and a very good correlation between the topography and the potential data is observed. It is shown that in the thick pentacene grains the potential is homogeneous and independent of the gate bias applied with negligible charge trapping, while in the thin IGRs the potential varies with the applied gate bias, indicating that only an incomplete accumulation layer can be formed. Clear evidence for preferential charge trapping in the thin IGRs is obtained.
New Technologies for Improving the High Frequency Performance of AlGaN/GaN High Electron Mobility Transistors (2008)

In this paper, we have used a combination of physical analysis, numerical simulation and experimental work to overcome some of the main challenges in AlGaN/GaN high electron mobility transistors (HEMTs) for high frequency applications. In spite of their excellent material properties, GaN-based HEMTs are still below the theoretical predictions in their high frequency performance. If the frequency performance could be improved, the superior breakdown characteristics of nitride semiconductors would make these devices the best option for power amplifiers at Ka and even W band frequencies. To achieve this goal, we have first identified some of the critical parameters that limit the high frequency performance of AlGaN/GaN HEMTs and we have demonstrated several technologies to increase the performance. Some of these technologies include deep-submicron T-gate technology, thin-body GaN HEMTs, and advanced drain delay engineering.
<title>Monolithic wavelength-graded VCSEL and wavelength-selective photodetector arrays for wavelength-division-multiplexed optical interconnect applications</title> (1998)

Monolithic, uniformly-wavelength-graded, vertical-cavity surface- emitting laser (VCSEL) and wavelength-selective resonance- enhanced photodetector (REPD) arrays are key enabling technologies for many wavelength-multiplexed optical network and interconnect architectures. These arrays can be produced in a repeatable and uniform manner by controlling the local MOCVD growth rate of the epilayers on a topographically patterned substrate, which resulted in wavelength-differentiated devices with more uniform optical characteristics. Multi-wavelength VCSEL and REPD arrays have been monolithically integrated on the same substrate to improve the wavelength matching between the source and detector elements. The performance characteristics of these arrays are discussed. We also describe a wavelength-division- multiplexing and demultiplexing experiment in which several channels of optical data are multiplexed together using a multi- wavelength VCSEL array and transmitted on a single optical fiber, and are demultiplexed at the other end using a wavelength- selective REPD array with closely-matching wavelengths.