gebhart/patrepeval huggingface dataset:
Microbead Chemical Switches:  An Approach to Detection of Reactive Organophosphate Chemical Warfare Agent Vapors (2006)

In this article, we describe the preparation and application of microbeads that exhibit a "turn on" fluorescence response within seconds of exposure to diethyl chlorophosphate (DCP) vapor. This sensing approach is modeled after the mechanism for acetylcholinesterase enzyme activity inhibition and uses a specific and irreversible reaction between phosphoryl halides and a fluorescent indicator. The microbeads are fabricated by adsorbing fluoresceinamine (FLA) onto carboxylate-functionalized polymer microbeads coated with poly(2-vinylpyridine) (PVP). When the microbeads are subjected to DCP vapor, the conversion of FLA into a phosphoramide causes a rapid and intense fluorescence increase. The PVP layer provides a high density of proton-accepting pyridine nitrogen sites that neutralize the HCl released during the reaction, thereby maintaining high product fluorescence, even after vapor exposure. No significant response is observed when the microbeads are subjected to other nerve agent simulants, a mustard gas simulant, and volatile organics. The size, sensitivity, and subsecond response of these microbeads make them suitable for nerve agent vapor detection and inclusion into microbead sensor arrays.
<title>Multimedia systems in ultrasound image boundary detection and measurements</title> (1997)

Ultrasound as a medical imaging modality offers the clinician a real-time of the anatomy of the internal organs/tissues, their movement, and flow noninvasively. One of the applications of ultrasound is to monitor fetal growth by measuring biparietal diameter (BPD) and head circumference (HC). We have been working on automatic detection of fetal head boundaries in ultrasound images. These detected boundaries are used to measure BPD and HC. The boundary detection algorithm is based on active contour models and takes 32 seconds on an external high-end workstation, SUN SparcStation 20/71. Our goal has been to make this tool available within an ultrasound machine and at the same time significantly improve its performance utilizing multimedia technology. With the advent of high- performance programmable digital signal processors (DSP), the software solution within an ultrasound machine instead of the traditional hardwired approach or requiring an external computer is now possible. We have integrated our boundary detection algorithm into a programmable ultrasound image processor (PUIP) that fits into a commercial ultrasound machine. The PUIP provides both the high computing power and flexibility needed to support computationally-intensive image processing algorithms within an ultrasound machine. According to our data analysis, BPD/HC measurements made on PUIP lie within the interobserver variability. Hence, the errors in the automated BPD/HC measurements using the algorithm are on the same order as the average interobserver differences. On PUIP, it takes 360 ms to measure the values of BPD/HC on one head image. When processing multiple head images in sequence, it takes 185 ms per image, thus enabling 5.4 BPD/HC measurements per second. Reduction in the overall execution time from 32 seconds to a fraction of a second and making this multimedia system available within an ultrasound machine will help this image processing algorithm and other computer-intensive imaging applications become a practical tool for the sonographers in the feature.
Assembly and Application of a Three‐Dimensional Human Corneal Tissue Model (2019)

The cornea provides a functional barrier separating the outside environment from the intraocular environment, thereby protecting posterior segments of the eye from infection and damage. Pathological changes that compromise the structure or integrity of the cornea may occur as a result of injury or disease and can lead to debilitating effects on visual acuity. Over 10 million people worldwide are visually impaired or blind due to corneal opacity. Thus, physiologically relevant in vitro approaches to predict corneal toxicity of chemicals or effective treatments for disease prior to ocular exposure, as well as to study the corneal effects of systemic, chronic conditions, such as diabetes, are needed to reduce use of animal testing and accelerate therapeutic development. We have previously bioengineered an innervated corneal tissue model using silk protein scaffolds to recapitulate the structural and mechanical elements of the anterior cornea and to model the functional aspects of corneal sensation with the inclusion of epithelial, stromal, and neural components. The purpose of this unit is to provide a step-by-step guide for preparation, assembly, and application of this three-dimensional corneal tissue system to enable the study of corneal tissue biology. © 2019 by John Wiley & Sons, Inc.
Liquid Propellant Guns (1987)

Abstract : Liquid propellants have been the focus of periodic research efforts since just after the Second World War. Early efforts centered on the mechanically simple bulk loaded liquid propellant gun. A large number of experimental gun firings were conducted, and semi-quantitative models of the bulk loaded interior ballistic process were developed. However, the ballistic control required of a practical gun system has been achieved. In contrast, the regenerative liquid propellant gun has demonstrated the required ballistic control, but at the expense of mechanical complexity heretofore unknown in gun systems. Nevertheless, the regenerative liquid propellant gun may provide the mechanism for the development of a practical weapon system based on a liquid gun propellant.
High thermal power density heat transfer (1980)

Heat from a high temperature heat pipe is transferred through a vacuum or a gap filled with electrically nonconducting gas to a cooler heat pipe. The heat pipe is used to cool the nuclear reactor while the heat pipe is connected thermally and electrically to a thermionic converter. If the receiver requires greater thermal power density, geometries are used with larger heat pipe areas for transmitting and receiving energy than the area for conducting the heat to the thermionic converter. In this way the heat pipe capability for increasing thermal power densities compensates for the comparatively low thermal power densities through the electrically non-conducting gap between the two heat pipes.
Laser Ablation Electrospray Ionization Mass Spectrometry: Mechanisms, Configurations and Imaging Applications (2014)

Laser ablation electrospray ionization (LAESI) combines the microsampling capabilities of mid-IR lasers with the high ion yields of electrosprays to produce sample-specific ions from biomedical and other specimens of high water content. To facilitate fundamental understanding of this technique, four critical aspects of the underlying physical phenomena are discussed. Fast imaging experiments and fluid dynamic calculations indicate that the sampling process by mid-IR laser ablation is governed by particulate ejection due to the recoil pressure of the expanding laser plume. Spray diagnostic studies show that control over the spraying regimes of the electrospray offers clues to achieve high ion yields. Tailoring the merging of the laser ablation plume with the electrospray offers additional ways to improve sensitivity. Measured internal energies of the ions produced by LAESI and regular electrospray ionization show them to be indistinguishable. Since its inception in 2007, LAESI has been implemented in diverse configurations, including conventional reflection and transmission geometries, heat-assisted LAESI for enhanced detection of apolar molecules, optical fiber-based laser-pulse delivery for improved focusing, and plume collimation for heightened sensitivity. LAESI supports several spatial profiling and molecular imaging modalities for biological tissues. Rastering the surface with the laser beam and collecting spectra point-by-point is the basis of constructing lateral images for ions associated with hundreds of metabolites and lipids. Because ablation by consecutive laser pulses can sample subsurface layers for analysis, depth profiling can also be performed. Combining lateral imaging with depth profiling is the basis of the three-dimensional reconstruction of molecular distributions in tissues. To improve the fidelity of molecular imaging, we introduced and implemented a cell-by-cell imaging strategy that promises to reveal new information on cellular transport and signaling processes in tissues.
Structure activity relationships of monocyte chemoattractant proteins in complex with a blocking antibody (2006)

Monocyte chemoattractant proteins (MCPs) are cytokines that direct immune cells bearing appropriate receptors to sites of inflammation or injury and are therefore attractive therapeutic targets for inhibitory molecules. 11K2 is a blocking mouse monoclonal antibody active against several human and murine MCPs. A 2.5 A structure of the Fab fragment of this antibody in complex with human MCP-1 has been solved. The Fab blocks CCR2 receptor binding to MCP-1 through an adjacent but distinct binding site. The orientation of the Fab indicates that a single MCP-1 dimer will bind two 11K2 antibodies. Several key residues on the antibody and on human MCPs were predicted to be involved in antibody selectivity. Mutational analysis of these residues confirms their involvement in the antibody-chemokine interaction. In addition to mutations that decreased or disrupted binding, one antibody mutation resulted in a 70-fold increase in affinity for human MCP-2. A key residue missing in human MCP-3, a chemokine not recognized by the antibody, was identified and engineering the preferred residue into the chemokine conferred binding to the antibody.
A GHF7 CELLULASE FROM THE PROTIST SYMBIONT COMMUNITY OF <i>Reticulitermes flavipes</i> ENABLES MORE EFFICIENT LIGNOCELLULOSE PROCESSING BY HOST ENZYMES (2013)

Termites and their gut microbial symbionts efficiently degrade lignocellulose into fermentable monosaccharides. This study examined three glycosyl hydrolase family 7 (GHF7) cellulases from protist symbionts of the termite Reticulitermes flavipes. We tested the hypotheses that three GHF7 cellulases (GHF7-3, GHF7-5, and GHF7-6) can function synergistically with three host digestive enzymes and a fungal cellulase preparation. Full-length cDNA sequences of the three GHF7s were assembled and their protist origins confirmed through a combination of quantitative PCR and cellobiohydrolase (CBH) activity assays. Recombinant versions of the three GHF7s were generated using a baculovirus-insect expression system and their activity toward several model substrates compared with and without metallic cofactors. GHF7-3 was the most active of the three cellulases; it exhibited a combination of CBH, endoglucanase (EGase), and β-glucosidase activities that were optimal around pH 7 and 30°C, and enhanced by calcium chloride and zinc sulfate. Lignocellulose saccharification assays were then done using various combinations of the three GHF7s along with a host EGase (Cell-1), beta-glucosidase (β-glu), and laccase (LacA). GHF7-3 was the only GHF7 to enhance glucose release by Cell-1 and β-glu. Finally, GHF7-3, Cell-1, and β-glu were individually tested with a commercial fungal cellulase preparation in lignocellulose saccharification assays, but only β-glu appreciably enhanced glucose release. Our hypothesis that protist GHF7 cellulases are capable of synergistic interactions with host termite digestive enzymes is supported only in the case of GHF7-3. These findings suggest that not all protist cellulases will enhance saccharification by cocktails of other termite or fungal lignocellulases.
Synthesis of a helical metallocene oligomer (1986)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of a helical metallocene oligomerAnantha. Sudhakar, Thomas J. Katz, and Bing Wei. YangCite this: J. Am. Chem. Soc. 1986, 108, 10, 2790–2791Publication Date (Print):May 1, 1986Publication History Published online1 May 2002Published inissue 1 May 1986https://pubs.acs.org/doi/10.1021/ja00270a068https://doi.org/10.1021/ja00270a068research-articleACS PublicationsRequest reuse permissionsArticle Views473Altmetric-Citations61LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
Calibration of a Digital Hydrophone Line Array at Low Frequency (2016)

The challenges of comparison calibrations of hydrophones in linear arrays at low frequencies are inherent in the length of the array, number of hydrophones, difficulty in achieving free-field conditions, and lack of a suitable low-frequency projector. These challenges were addressed by the development of complementary methods to simultaneously measure the complex sensitivity in the acoustic data channels of hydrophone line arrays with digital telemetry systems. The voltage sensitivities and RC time constants of the array data channels were then estimated by nonlinear regression of calibration data to a simplified model of the acoustic data channel. The methods are demonstrated by the simultaneous calibration of 200 data channels of a digital hydrophone line array at 1/3 octave band center frequencies ranging from 1.2 to 400 Hz. The 95% confidence interval of the voltage sensitivity estimates was not more than 1 dB.
Three-dimensional imaging of microstructures by an improved compact digital holographic microscope (ICDHM) with dual wavelength (2015)

An improved compact digital holographic microscope (ICDHM) is developed for three-dimensional imaging of microstructures. This system is based on lensless magnification using a diverging wave. A point source generated by a long working distance microscope objective is located into the cube beam-splitter to get a higher numerical aperture (NA) of the system. The lateral resolution and the field-of-view of the system are confirmed with a calibration experiment. For the case of the optical path lengths (OPL) of object with step pattern larger than the wavelength, the traditional phase unwrapping algorithms cannot be unequivocally determinate, resulting in a 2π phase ambiguity. To solve this problem, dual wavelength phase unwrapping method was integrated into ICDHM, which extends the measuring capability of ICDHM over several microns of range. The experimental results demonstrate that the developed system is well suitable for the measurement of MEMS and Micro systems samples with high resolution.
Extracellular ATP and CD39 Activate cAMP-Mediated Mitochondrial Stress Response to Promote Cytarabine Resistance in Acute Myeloid Leukemia (2020)

Relapses driven by chemoresistant leukemic cell populations are the main cause of mortality for patients with acute myeloid leukemia (AML). Here, we show that the ectonucleotidase CD39 (ENTPD1) is upregulated in cytarabine-resistant leukemic cells from both AML cell lines and patient samples <i>in vivo</i> and <i>in vitro</i>. CD39 cell-surface expression and activity is increased in patients with AML upon chemotherapy compared with diagnosis, and enrichment in CD39-expressing blasts is a marker of adverse prognosis in the clinics. High CD39 activity promotes cytarabine resistance by enhancing mitochondrial activity and biogenesis through activation of a cAMP-mediated adaptive mitochondrial stress response. Finally, genetic and pharmacologic inhibition of CD39 ecto-ATPase activity blocks the mitochondrial reprogramming triggered by cytarabine treatment and markedly enhances its cytotoxicity in AML cells <i>in vitro</i> and <i>in vivo</i>. Together, these results reveal CD39 as a new residual disease marker and a promising therapeutic target to improve chemotherapy response in AML. SIGNIFICANCE: Extracellular ATP and CD39-P2RY13-cAMP-OxPHOS axis are key regulators of cytarabine resistance, offering a new promising therapeutic strategy in AML.<i>This article is highlighted in the In This Issue feature, p. 1426</i>.
Faster secure computation for biometric identification using filtering (2012)

Several attempts have been made to apply Secure Multiparty Computation (SMC) to the context of biometric recognition. Such constructions are very bandwidth and time-consuming. In order to reduce both consumptions, we propose a new construction for biometric identification based on filtering techniques that has the same security properties as the other SMC-based schemes but runs significantly faster while keeping good biometric performances. We propose as an example a secure iris identification algorithm with a fast filtering phase based on Hamming distance. We moreover present implementation results for this proposal that confirm our improvements.
A microbial–enzymatic strategy for producing chondroitin sulfate glycosaminoglycans (2018)

Chondroitin sulfate has been widely used in both medical and clinical applications. Commercial chondroitin sulfate has been mainly acquired from animal tissue extraction. Here we report a new two-step biological strategy for producing chondroitin sulfate A and chondroitin sulfate C. First, the chondroitin biosynthesis pathway in a recombinant Bacillus subtilis strain using sucrose as carbon source was systematically optimized and the titer of chondroitin was significantly enhanced to 7.15 g/L. Then, specific sulfation transformation systems were successfully constructed and optimized by combining the purified aryl sulfotransferase IV (ASST IV), chondroitin 4-sulfotransferase (C4ST) and chondroitin 6-sulfotransferase (C6ST). Chondroitin sulfate A and C were enzymatically transformed from chondroitin at conversion rates of 98% and 96%, respectively. The present biological strategy has great potential to be scaled up for biosynthesis of chondroitin sulfate A and C from cheap carbon sources.
Perturbed quantization steganography with wet paper codes (2004)

In this paper, we introduce a new approach to passive-warden steganography in which the sender embeds the secret message into a certain subset of the cover object without having to share the selection channel with the recipient. An appropriate information-theoretical model for this communication is writing in memory with (a large number of) defective cells [1]. We describe a simple variable-rate random linear code for this channel (the "wet paper" code) and use it to develop a new steganographic methodology for digital media files - Perturbed Quantization. In Perturbed Quantization, the sender hides data while processing the cover object with an information-reducing operation, such as lossy compression, downsampling, A/D conversion, etc. The sender uses the cover object before processing as side information to confine the embedding changes to those elements of the processed cover object whose values are the most "uncertain". This informed-sender embedding and uninformed-recipient message extraction improves steganographic security because an attacker cannot easily determine from the processed stego object the location of embedding changes. Heuristic is presented and supported by blind steganalysis [2] that a specific case of Perturbed Quantization for JPEG images is significantly less detectable than current JPEG steganographic methods.
Multiscale video representation using multiresolution motion compensation and wavelet decomposition (1993)

A multiscale video representation using wavelet decomposition and variable-block-size multiresolution motion estimation (MRME) is presented. The multiresolution/multifrequency nature of the discrete wavelet transform makes it an ideal tool for representing video sources with different resolutions and scan formats. The proposed variable-block-size MRME scheme utilizes motion correlation among different scaled subbands and adapts to their importance at different layers. The algorithm is well suited for interframe HDTV coding applications and facilitates conversions and interactions between different video coding standards. Four scenarios for the proposed motion-compensated coding schemes are compared. A pel-recursive motion estimation scheme is implemented in a multiresolution form. The proposed approach appears suitable for the broadcast environment where various standards may coexist simultaneously.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Determination of crosslinking density of hydrogels prepared from microcrystalline cellulose (2012)

Abstract Hydrogels with four different plant‐based microcrystalline cellulose concentrations were prepared using the self‐assembly technique. The interaction parameter between cellulose and water was determined by the classical Flory‐Huggins theory, and was found to be around 0.44 with weak concentration dependence. The crosslinking density in these hydrogels was measured by both the Mooney‐Rivlin equation and the Flory‐Rehner theory. Reasonable consistency was found between the two methods albeit results from the Flory‐Rehner theory were slightly higher due to the contribution from the physical crosslinks. The crosslinking density values for all four hydrogels determined from both methods were found to range from 19 to 56 mol/m 3 . © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Fair Transfer Learning with Missing Protected Attributes (2019)

Risk assessment is a growing use for machine learning models. When used in high-stakes applications, especially ones regulated by anti-discrimination laws or governed by societal norms for fairness, it is important to ensure that learned models do not propagate and scale any biases that may exist in training data. In this paper, we add on an additional challenge beyond fairness: unsupervised domain adaptation to covariate shift between a source and target distribution. Motivated by the real-world problem of risk assessment in new markets for health insurance in the United States and mobile money-based loans in East Africa, we provide a precise formulation of the machine learning with covariate shift and score parity problem. Our formulation focuses on situations in which protected attributes are not available in either the source or target domain. We propose two new weighting methods: prevalence-constrained covariate shift (PCCS) which does not require protected attributes in the target domain and target-fair covariate shift (TFCS) which does not require protected attributes in the source domain. We empirically demonstrate their efficacy in two applications.