gebhart/patrepeval huggingface dataset:
Dead time generator for synchronous boost converters with GaN transistors (2014)

An analog dynamic dead time generator for synchronous boost converters based on GaN transistors is presented. A prototype was designed to operate at switching frequencies in the MHz range, with wide variations of the output voltage, and experimentally demonstrated its capability to stabilize the dead time duration to a few nanoseconds, independent of wide variations of the switching times of the transistor in use.
Understanding Hydraulic Fracture Growth: Tricky but Not Hopeless (1999)

Abstract Hydraulic fracturing has proven to be a fruitful well stimulation technique in an ever-increasing range of environments. Application has spread from the original target of enhancing production rates from low permeability reservoirs to fracturing of poorly consolidated high perm reservoirs, fracturing of horizontal and deviated wellbores, fracturing of unconventional (often naturally fractured) reservoirs, fracturing for waste disposal, etc. While significant progress has been made in engineering hydraulic fracturing treatments, we are still often humbled and alarmed by the apparent complexity of the process. This paper does not present "the answer" to this complex problem. Instead it attempts to shed some light on areas where we must be careful with our assumptions. This paper presents examples of measuring (inferring) hydraulic fracture growth in a number of different environments. For each example we discuss the implications of the observed fracture growth. For example, how accurate were the fracture model predictions? How effective is the current completion / fracturing strategy in achieving the design goals? What are we learning about the factors or mechanisms that govern hydraulic fracture growth? How can these new insights aid production enhancement? While most of the direct observations of hydraulic fracture growth are from downhole-tilt fracture mapping, data from many additional diagnostics are also included (post-frac logging, production response, intersections with offset wells, microseismic mapping, etc). Perhaps the most surprising observation is the observed range of fracture height growth: spanning from well-contained fractures in the absence of significant formation stress barriers, to extremely uncontained fracture height growth. Observations of fracture width, length, and asymmetry will also be presented and discussed.
Microarrays of silver nanowires embedded in anodic alumina membrane templates: size dependence of polarization characteristics (2006)

Polarization characteristics of microarrays of silver nanowires embedded in an anodic alumina membrane are theoretically investigated. The microarrays mainly transmit the p-polarized wave, whereas they strongly attenuate the s-polarized wave in the near- and mid-infrared spectral range. We show that the sizes (e.g., diameter, spacing, and ratio of diameter to spacing) of the nanowires strongly affect the optical losses for the polarized waves. It is predicted that large extinction ratios and small insertion losses can be simultaneously achieved by an appropriate choice of the ratio and the diameter. An optimized design of a nanowire grid polarizer at near- and mid-infrared wavelengths is presented.
Measuring and Mapping Cardiac Fiber and Laminar Architecture Using Diffusion Tensor MR Imaging (2005)

The ventricular myocardium is known to exhibit a complex spatial organization, with fiber orientation varying as a function of transmural location. It is now well established that diffusion tensor magnetic resonance imaging (DTMRI) may be used to measure this fiber orientation at high spatial resolution. Cardiac fibers are also known to be organized in sheets with surface orientation varying throughout the ventricles. This article reviews results on use of DTMRI for measuring ventricular fiber orientation, as well as presents new results providing strong evidence that the tertiary eigenvector of the diffusion tensor is aligned locally with the cardiac sheet surface normal. Considered together, these data indicate that DTMRI may be used to reconstruct both ventricular fiber and sheet organization. This article also presents the large deformation diffeomorphic metric mapping (LDDMM) algorithm and shows that this algorithm may be used to bring ensembles of imaged and reconstructed hearts into correspondence (e.g., registration) so that variability of ventricular geometry, fiber, and sheet orientation may be quantified. Ventricular geometry and fiber structure is known to be remodeled in a range of disease processes; however, descriptions of this remodeling have remained subjective and qualitative. We anticipate that use of DTMRI for reconstruction of ventricular anatomy coupled with application of the LDDMM method for image volume registration will enable the detection and quantification of changes in cardiac anatomy that are characteristic of specific disease processes in the heart. Finally, we show that epicardial electrical mapping and DTMRI imaging may be performed in the same hearts. The anatomic data may then be used to simulate electrical conduction in a computational model of the very same heart that was mapped electrically. This facilitates direct comparison and testing of model versus experimental results and opens the door to quantitative measurement, modeling, and analysis of the ways in which remodeling of ventricular microanatomy influences electrical conduction in the heart.
Flow cytometry and the stability of phycoerythrin‐tandem dye conjugates (2009)

Routine clinical flow cytometric procedures demand rigorous, simple, and reproducible procedures for spectral compensation. The current, often laborious, spectral compensation procedures are the result of variability in instrument settings, instrument performance, and variability in reagents. In particular, the use of tandem dye conjugates necessitates elaborate spectral compensation procedures that need to be applied frequently. Manufacturer, lot number, and handling procedures are considered the key aspects affecting the fluorescence characteristics of tandem dyes. A better understanding of how specific conditions affect the variability in emission spectra of tandem dyes can lead to a considerable increase in reliability of measurements and a potential simplification of setup procedures for routine, clinical flow cytometry. We investigated the effect of light exposure, handling, and storage conditions on the fluorescence characteristics of some common phycoerythrin tandem fluorochromes. In general, PE-Cy5 showed the lowest degradation rates, whereas PE-Cy7 showed the highest. During storage, long-term degradation rates were lowest for reagents packaged using an extra light protective approach. Under these conditions, a degradation rate of 0.9%/month of a PE-Cy7 conjugate decreased to 0.3%/month. As degradation rates were minimized, we studied the effect of slow degradation of a set of tandem dye conjugates on compensation matrix values over several months. Finally, we explored the effect of slow degradation on flow cytometric analysis using the same compensation settings for extended periods for an analysis template with preset regions and gating strategies.
Site-specific phosphorylation of tau inhibits amyloid-β toxicity in Alzheimer’s mice (2016)

Amyloid-β (Aβ) toxicity in Alzheimer's disease (AD) is considered to be mediated by phosphorylated tau protein. In contrast, we found that, at least in early disease, site-specific phosphorylation of tau inhibited Aβ toxicity. This specific tau phosphorylation was mediated by the neuronal p38 mitogen-activated protein kinase p38γ and interfered with postsynaptic excitotoxic signaling complexes engaged by Aβ. Accordingly, depletion of p38γ exacerbated neuronal circuit aberrations, cognitive deficits, and premature lethality in a mouse model of AD, whereas increasing the activity of p38γ abolished these deficits. Furthermore, mimicking site-specific tau phosphorylation alleviated Aβ-induced neuronal death and offered protection from excitotoxicity. Our work provides insights into postsynaptic processes in AD pathogenesis and challenges a purely pathogenic role of tau phosphorylation in neuronal toxicity.
External Infrared Reflection Absorption Spectrometry of Monolayer Films at the Air-Water Interface (1995)

The theory and practice of external infrared reflection absorption spectrometry (IRRAS) as applied to monomolecular films at the air-water interface are reviewed. The observed IR frequencies for films of amphiphilic species provide information about the conformational states of the hydrocarbon chains and the hydrogen bonding and ionization states of the polar head groups, under conditions of controlled surface pressure. Determination of molecular orientation is also feasible and requires detailed consideration of the reflection-absorption properties of the three- phase (air-monolayer-water) system. Current theoretical approaches are described. Applications of IRRAS to the study of single- and double-chain amphiphiles and proteins are reviewed, and initial excursions into biochemistry (interfacial enzyme catalysis) and physiology (pulmonary surfactant function) are reported.
Highly Active Antiretroviral Therapy Started during Pregnancy or Postpartum Suppresses HIV‐1 RNA, but Not DNA, in Breast Milk (2005)

HAART suppressed cell-free HIV-1 RNA in breast milk and may therefore reduce mother-to-child transmission (MTCT) of HIV-1 via breast-feeding. However, HAART initiated during pregnancy or early after delivery had no apparent effect on cell-associated HIV-1 DNA loads in breast milk. Clinical trials to determine MTCT among breast-feeding women receiving HAART are needed.
Obstacle avoidance for platforms in three-dimensional environments (2016)

The field of obstacle avoidance is a well-researched area. Despite this, research on obstacle avoidance in three dimensions is surprisingly sparse. For platforms which are able to navigate three-di ...
Sequence comparisons of retroviral proteins: relative rates of change and general phylogeny. (1988)

The inferred amino acid sequences of 10 specific gene products from nine retroviruses were aligned by computer, all evolutionary distances between them calculated, and evolutionary trees constructed. Not unexpectedly, the various gene products are changing at different rates, the reverse transcriptase being the least and the envelope proteins the most different from one retrovirus to another. For the most part, trees based on the retroviral enzyme sequences are congruent, indicating that extensive genetic recombination has not been a major factor in the evolution of the central part of the genome. In the case of envelope protein sequences, however, the sequences clearly exhibit evidence of multiple cross-over events between quite distantly related retroviruses. A composite phylogenetic tree was constructed from the four retroviral enzyme sequences, and a number of important historical happenings were interpreted in the light of the time scale it affords.
Kinetics of Palm Oil Methanolysis (2007)

Abstract A kinetics study of palm oil methanolysis was conducted at three different temperatures and three different concentrations of catalyst, sodium hydroxide, keeping constant the molar ratio of methanol to oil and the rotational speed of the impeller (6:1 and 400 rpm). The maximum conversion of palm oil and productivity to methyl esters were obtained at 60 °C and 1 wt% of NaOH based on palm oil, and they were 100 and 97.6%, respectively. The statistical analysis of conversions of palm oil and productivities to methyl esters as functions of temperature and concentration of catalyst, after 80 min of reaction, allowed them to fit second order polynomial equations, which adequately describe the experimental behavior. The experimental data appear to be a good fit into a second order kinetic model for the three stepwise reactions, and the reaction rate constants and the activation energies were determined. In this article we present the kinetic constant and activation energies for the experiments with 0.2% wt of NaOH. The effect of molar ratio on the concentration of products was investigated, while the temperature (55 °C), the concentration of catalyst (0.60 wt% of NaOH), and the rotational speed (400 rpm), were held constant. The results showed that the conversion and the productivity increased due to methanol excess, and were higher for the reactions with a molar ratio of 6:1.
Automated Manufacture of Spinal Instrumentation (2006)

Current scoliosis corrective surgeries may include the use of multiple instrumentation devices including screws, wires, nuts, and rods. The instrumentation in most cases is implemented in its native form. However, the instrumentation rods must be contoured to a desired shape prior to fixation to the spine. The contouring of the instrumentation rod is currently performed manually and may require significant time for completion. This results in an increase of operation time and reduced accuracy of the instrumentation rod. The feasibility of automating the contouring process was studied to determine if the time required to contour a rod could be reduced and if the accuracy of the rod could be improved. This study built upon a previous effort to construct a prototype that would automate the manufacture of spinal instrumentation rods. The Spinal Instrumentation Bending Prototype (SIBP) focused on ease of use, time of manufacture, and accuracy. In order to complete the manufacturing process, the current SIBP uses a set of three dimensional control points that represent the desired contour of the rod. These control points are translated into manufacturing inputs that control the SIBP. The control application for the SIBP contains local and global feedback routines that correct for any manufacturing errors. A comparative study was made between the SIBP and an experienced orthopedic surgeon to determine the level of bending accuracy improvement.
Invariants of the velocity-gradient tensor in a spatially developing inhomogeneous turbulent flow (2017)

Tomographic particle image velocimetry experiments were performed in the near field of the turbulent flow past a square cylinder. A classical Reynolds decomposition was performed on the resulting velocity fields into a time invariant mean flow and a fluctuating velocity field. This fluctuating velocity field was then further decomposed into coherent and residual/stochastic fluctuations. The statistical distributions of the second and third invariants of the velocity-gradient tensor were then computed at various streamwise locations, along the centreline of the flow and within the shear layers. These invariants were calculated from both the Reynolds-decomposed fluctuating velocity fields and the coherent and stochastic fluctuating velocity fields. The range of spatial locations probed incorporates regions of contrasting flow physics, including a mean recirculation region and separated shear layers, both upstream and downstream of the location of peak turbulence intensity along the centreline. These different flow physics are also reflected in the velocity gradients themselves with different topologies, as characterised by the statistical distributions of the constituent enstrophy and strain-rate invariants, for the three different fluctuating velocity fields. Despite these differing flow physics the ubiquitous self-similar 'tear drop'-shaped joint probability density function between the second and third invariants of the velocity-gradient tensor is observed along the centreline and shear layer when calculated from both the Reynolds decomposed and the stochastic velocity fluctuations. These 'tear drop'-shaped joint probability density functions are not, however, observed when calculated from the coherent velocity fluctuations. This 'tear drop' shape is classically associated with the statistical distribution of the velocity-gradient tensor invariants in fully developed turbulent flows in which there is no coherent dynamics present, and hence spectral peaks at low wavenumbers. The results presented in this manuscript, however, show that such 'tear drops' also exist in spatially developing inhomogeneous turbulent flows. This suggests that the 'tear drop' shape may not just be a universal feature of fully developed turbulence but of turbulent flows in general.
Tag Match Advertising Business Model in Mobile RFID Environment (2008)

This paper proposes the 'Tag Match' advertising business model which uses mobile RFID. Tag Match Advertising (TMA) combines features of the mobile RFID characteristics and content match advertising model on the Internet. TMA model can be defined as 'an advertising model, based on mobile RFID application, which offers the most appropriate advertisement for users after the consideration of users' demographic information, the location and time when users scan a RFID tag and the content of the tag when users scan it'. This paper describes its scenarios, processes, participants and their benefits. Tag Match Advertising (TMA) is a ubiquitous version of content match advertising on the Internet.
Corneal re-epithelialization in galactosemic rats. (1983)

Abnormalities in corneal epithelial healing in diabetic patients have been described recently. Defects in corneal re-epithelialization in diabetic rats have been reported, and it was found that treatment with aldose reductase (AR) inhibitors effectively prevented these defects. Experiments using galactosemic rats to study further the role of AR in these defects, since AR is known to be the common factor involved in sugar cataractogeneses, are reported herein. Similar defects in corneal re-epithelialization in galactosemic rats as in diabetic rats were found. The delay in re-epithelialization was documented by computer planimetry. Light microscopy showed marked corneal stroma edema and wider intercellular spaces in the epithelium after complete re-epithelialization, while scanning electron microscopy revealed fewer filopodia projecting from the leading margin during the active migration stage. These defects were prevented by treating galactosemic rats with the aldose reductase inhibitor, Pfizer's Sorbinil. These suggest that AR plays a role in the defects in corneal re-epithelialization observed in diabetes.
[Succinate dehydrogenase and cytochrome oxidase activity in rat tissues during prolonged hypokinesia]. (1982)

The activity of cytochrome oxidase in the liver, skeletal muscles, kidneys, brain and lungs of 56 white rats decreased on days 15 and 60 of the hypokinetic study. The activity of succinate dehydrogenase significantly lowered in the brain and slightly diminished in the lungs and skeletal muscles on the same days. The activity of succinate dehydrogenase in the liver increased on the 90th hypokinetic day.
Identification of seven genes regulated by wild-type p53 in a colon cancer cell line carrying a well-controlled wild-type p53 expression system. (1999)

We applied a differential display method to screen mRNAs isolated from a newly established cell line that carried a wild-type p53 transgene under control of the lactose operon. To investigate the p53 signaling pathway, we looked for genes whose expression was significantly induced or suppressed by induction of wild-type p53 protein, and identified seven. DNA sequence analyses revealed that the two genes that were upregulated encoded isozyme 6 of aldehyde dehydrogenase (ALDH6) and subunit I of cytochrome c oxidase (COI). The five genes that were downregulated encoded protein-tyrosine kinase (Syk), high mobility group chromosomal protein 17 (HMG-17), transferrin receptor, human alpha-tubulin, and sds22-like protein. The results indicated that genes related to cell cycle regulation, cell respiration, and cytoskeletal structure are involved in the process of growth arrest induced by wild-type p53.
Tracking Large Variable Numbers of Objects in Clutter (2007)

We propose statistical data association techniques/or visual tracking of enormously large numbers of objects. We do not assume any prior knowledge about the numbers involved, and the objects may appear or disappear anywhere in the image frame and at any time in the sequence. Our approach combines the techniques of multitarget track initiation, recursive Bayesian tracking, clutter modeling, event analysis, and multiple hypothesis filtering. The original multiple hypothesis filter addresses an NP-hard problem and is thus not practical. We propose two cluster-based data association approaches that are linear in the number of detections and tracked objects. We applied the method to track wildlife in infrared video. We have successfully tracked hundreds of thousands of bats which were flying at high speeds and in dense formations.
Cell Transformation Assays as Predictors of Human Carcinogenicity (1999)

4FRAME, Russell & Burch House, 9698 North Sherwood Street, Nottingham NG1 4EE, UK; 5ECVAM, JRC Institute for Health and Consumer Protection, 21020 Ispra (VA), Italy; 6Institute for In Vitro Sciences, 21 Firstfield Road, Suite 220, Gaithersburg, MD 20878, USA; 728/30 Via Trieste, 21030 Brinzio (VA), Italy; 8Division of Carcinogenesis and Differentiation, FSII, 0240, German Cancer Research Centre, im Neuenheimer Feld 280, 69120 Heidelberg, Germany; 9Covance Laboratories, Otley Road, Harrogate, North Yorkshire HG3 1PY, UK; 10Bureau of Chemical Substances and Preparations, Ministry of Land and Country Planning and Environment, 20 Avenue de Segur, 75302 Paris 07 SP, France; 11USC/Kenneth Norris Jr, Comprehensive Cancer Centre and Hospital, 1441 Eastlake Avenue, P.O. Box 33804, Los Angeles, CA 90033-0804, USA; 12Procter & Gamble, Temselaan 100, 1853 Strombeek-Bever, Brussels, Belgium; 13Department of Toxicology, Hamburg University Medical School, Grindelallee 117, 20146 Hamburg, Germany; 14Carcinogenesis Laboratory, FST Building, Michigan State University, East Lansing, MI 48824-1316, USA; 15Mutagenicity and Carcinogenicity Section, Federal Institute for Drugs and Medical Devices, Seestrasse 10, 13353 Berlin, Germany; 16Institute for Cancer Research, Laboratory for Environmental and Occupational Cancer, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway; 17Laboratory of Cell Toxicology, Department of Cellular and Genetic Toxicology, Hatano Research Institute/Food and Drug Safety Centre, 729-5 Ochiai, Hadano, Kanagawa 257, Japan; 18Centre des Sciences de lEnvironnment, 1 rue des Recollets, BP 94025, 57040 Metz Cedex 1, France; 19IARC, 150 cours Albert Thomas, 69372 Lyon Cedex 08, France
Uptake of Iodide by a Mixture of Metallic Copper and Cupric Compounds (1999)

Ability of copper/cupric compound mixtures to remove iodide from solution was investigated to predict sorption of radioactive iodine in the environment and to assess their use in a nuclear reprocessing method. Thermodynamic calculations were performed to study the stability of such mixtures in solution and to obtain equilibrium constants of Cu(0)/Cu(II)/I- and Cu(0)/Cu(II)/Cl- systems. Both calculations and experimental results showed that a Cu(0)/Cu3(OH)2(CO3)2 (azurite) mixture selectively uptakes iodide ions (initial concentrations: 10-2 and 10-1 M) in the presence of 10-1 M chloride ions. Reaction of iodide with copper powder and azurite crystal or copper plate and azurite powder have also been investigated, leading to precipitation of CuI onto massive copper phase. The different solids were separately analyzed by XPS and MEB-EDX, giving some insight in the uptake mechanism. It is proposed that soluble copper released by the cupric compound is reduced at the surface of metallic copper, leading to a preferential precipitation of CuI on copper surface.
Un patron dans l'Éducation (1998)

Barre Raymond. Un patron dans l'Éducation. In: Christian Beullac : un patron dans l'Éducation, 1978-1981. Journée d'études organisée le 3 juillet 1996 à Paris (Sorbonne) Paris : Institut national de recherche pédagogique, 1998. pp. 17-23. (Témoins et acteurs des politiques de l'éducation, 2)