gebhart/patrepeval huggingface dataset:
Formation of oriented high <i>T</i> <i>c</i> superconducting Bi-Sr-Ca-Cu-O thin films on silver substrates by organometallic chemical vapor deposition (1990)

Highly oriented thin films of the high Tc Bi-Sr-Ca-Cu-O superconductor have been deposited on silver substrates by low-pressure organometallic chemical vapor deposition. The volatile metalorganic complexes Cu(acetylacetonate)2, Sr(dipivaloylmethanate)2, Ca(dipivaloylmethanate)2, and triphenyl bismuth are used as precursors with N2O as a reactant gas. X-ray diffraction measurements reveal that the films deposited at 625 °C contain a mixture of the Bi2(Sr,Ca)2CuOx and Bi2(Sr,Ca)3Cu2Ox phases. The post-annealed films are predominantly composed of the Bi2(Sr,Ca)3Cu2Ox phase with preferential orientation of the crystallite c axes perpendicular to the substrate surface. Magnetic susceptibility measurements indicate the superconducting onset temperature of the annealed films to be at 80 K. The zero-field critical current density, estimated from magnetization measurements, is ∼3.9×105 A/cm2 at 5.5 K.
Functional near-infrared imaging reconstruction based on spatiotemporal features: venous occlusion studies (2015)

Noncontact-based near-infrared (NIR) optical imaging devices are developed for noninvasive tissue imaging in various clinical applications. Most of these devices focus on obtaining the spatial information for identification of blood vessels as in subsurface vein localization applications. In the current study, the spatiotemporal mapping of blood vessels based on functional information was performed using NIR optical imaging without the use of external contrast agents. A 710 nm LED source and a compact NIR-sensitive CCD camera system were employed during a simple cuff (0–60 mm Hg) experiment in order to acquire the dynamic NIR data from the dorsum of a hand. The spatiotemporal features of dynamic NIR data were extracted from the cuff experimental data to localize vessels according to blood dynamics. The blood vessels’ structure was reconstructed from the dynamic data based on the spatiotemporal features. Demonstrating the spatiotemporal feature of blood dynamic imaging using a portable noncontact NIR imaging device without external contrast agents is significant for applications such as peripheral vascular diseases and wound screening.
Molecular mimetics of polysaccharide epitopes as vaccine candidates for prevention of<i>Neisseria meningitidis</i>serogroup B disease (1999)

Neisseria meningitidis is a major cause of meningitis and sepsis. Despite nearly 25 years of work, there is no promising vaccine candidate for prevention of disease caused by meningococcal B strains. This review summarizes newer approaches for eliciting protective meningococcal B immune responses, including the use of molecular mimetics of group B polysaccharide and conserved membrane proteins as immunogens. The capsular polysaccharide of this organism is conserved and serum antibody to this capsule confers protection against disease. However, the immunogenicity of meningococcal B polysaccharide-based vaccines is poor. Further, a portion of the antibody elicited has autoantibody activity. Recently, our laboratory produced a panel of murine monoclonal antibodies (Mabs) that react specifically with capsular polysaccharide epitopes on meningococcal B that are distinct from host polysialic acid. These Mabs elicit complement-mediated bactericidal activity and confer passive protection in animal models. The anti-capsular Mabs were used to identify molecular mimetics from phage display peptide libraries. The resulting peptides were antigenic mimetics as defined by binding to the Mabs used to select them but, to date, are poor immunogenic mimetics in failing to elicit anti-capsular antibodies.
Designing method for sensing body mechanism of differential pressure transmitter using silicon diaphragm type pressure sensor (2002)

This paper describes a designing method of the three-diaphragm type sensing body of differential pressure transmitter for protecting silicon diaphragm type pressure sensor from an over-pressure. This method includes how to decide each stiffness of three metal diaphragms and liquid quantity filled in the sensing body. This method is applied to differential pressure transmitters with measuring ranges from 0-0.6 kPa to 0-400 kPa. As a result, transmitters with significant stabilities are obtained: a zero and span influence of a static pressure and an over-pressure are less than 0.2% at a line pressure of 15 MPa.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Protocol-level cooperation in wireless networks: Stable throughput and delay analysis (2009)

We study the impact of user cooperation in wireless networks on improving the stable throughput and delay performance. Specifically, we consider a multiaccess system in which a set of source users generate packets to deliver to a common destination. A cooperation strategy is proposed at the protocol level, where users with a better channel to the destination have the option to relay packets from users that are farther afield. For the case of erasure channels with single-packet reception, we derive the stable throughput regions under different multiple access policies based on such cooperation strategy. Then we prove that the stable throughput region of the cooperative system strictly contains the stable throughput region achieved without cooperation. We also assess the delay performance, and show that cooperation significantly reduces the delay of all users. Finally, we characterize the effect of inter-user channel quality on performance, and show that the gain in performance through cooperation increases as the channel quality improves. Our work offers an innovative perspective by implementing cooperation at the network protocol level, while taking into consideration of fading and attenuation at the physical layer as well as the nature of traffic burstiness in a network.
Histidines 13 and 14 in the Aβ sequence are targets for inhibition of Alzheimer's disease Aβ ion channel and cytotoxicity (2006)

The fact that Alzheimer's beta amyloid (Abeta) peptides forms cation channels in lipid bilayers was discovered during the course of our experiments in the laboratory of "Guayo" Rojas at NIH in Bethesda, Maryland (USA). Recently, we found that the Abeta ion channel could be blocked selectively with small peptides that copy the amino acid sequence of the predicted mouth region of the Abeta channel pore. We now have searched for the essential amino acid residues required for this blocking effect by mutations. We found that the ability of peptides to block Abeta channel activity could be lost by replacement of histidines 13 and 14 by alanine or lysine. The amino acid substitution also resulted in the loss of the capacity of the peptides to protect cells from Abeta cytotoxicity. These data thus contribute to the definition of the region of the Abeta sequence that participates in the formation of the channel pore. Additionally, these data support the hypothesis that the ion channel activity of Ab contributes significantly to the cytotoxic properties of Abeta. These data also emphasize the potential value in using inhibition of Abeta ion channel activity as an end point for Alzheimer's disease drug discovery.
Rational Design Strategy for the Realization of Red- to Near-Infrared-Emitting Alkynylgold(III) Complexes and Their Applications in Solution-Processable Organic Light-Emitting Devices (2019)

A new class of red- to near-infrared (NIR)-emitting cyclometalated alkynylgold(III) complexes was designed and synthesized. Red to NIR emission in the alkynylgold(III) complexes was realized, with the emission band maxima of the complexes in both solution and solid-state thin films found to extend to 823 and 730 nm, respectively. A small energy gap of down to 1.51 eV was achieved in the NIR-emitting complexes, as revealed from the electrochemical studies. Moreover, a large bathochromic shift of ∼1370 cm–1 can be obtained by simply changing the alkynyl ligand. NIR-emitting solution-processable organic light-emitting devices (OLEDs) were also realized, as exemplified by the electroluminescence properties with band maximum at 720 nm and Commission International de L’Éclairage coordinates of (0.67, 0.33) for devices based on complex 1b. This work not only demonstrates a design strategy to extend the emission of gold(III) complexes into the NIR regime but also represents the first report on gold(III)-based NIR-emitting OLEDs.
Effect of Selected Chemical Compounds on the Lubrication of Silicon Carbide (1999)

A systematic study has been conducted to investigate the interactions between selected chemical compounds and silicon carbide under boundary lubrication conditions. A modified four-ball wear tester was used to evaluate the additive effectiveness on silicon carbides lubricated with a paraffinic base oil containing one weight percent of additives. Friction, wear, and film morphology were observed for a range of chemical compounds containing chlorine, phosphorous, oxygen, and sulfur. Friction reduction was observed for chlorine containing compounds. At weight fraction of one percent under 40 kg load, wear reduction was obtained by all phosphorous containing compounds, polypropylene glycols, and oleic acid. At higher concentration and higher load, some sulfur containing compounds also reduced wear significantly. In general, all the effective wear reduction compounds generate films in the contact region. The films generated by phosphorous containing compounds appear to involve the iron impurity in the material.
Transparent ceramic garnet scintillator optimization via composition and co-doping for high-energy resolution gamma spectrometers(Conference Presentation) (2016)

Breakthrough energy resolution, R(662keV) <4%, has been achieved with an oxide scintillator, Cerium-doped Gadolinium Yttrium Gallium Aluminum Garnet, or GYGAG(Ce), by optimizing fabrication conditions. Here we describe the dependence of scintillation light yield and energy resolution on several variables: (1) Stoichiometry, in particular Gd/Y and Ga/Al ratios which modify the bandgap energy, (2) Processing methods, including vacuum vs. oxygen sintering, and (3) Trace co-dopants that influence the formation of Ce4+ and modify the intra-bandgap trap distribution. To learn about how chemical composition influences the scintillation properties of transparent ceramic garnet scintillators, we have measured: scintillation decay component amplitudes; intensity and duration of afterglow; thermoluminescence glow curve peak positions and amplitudes; integrated light yield; light yield non-proportionality, as measured in the Scintillator Light Yield Non-Proportionality Characterization Instrument (SLYNCI); and energy resolution for gamma spectroscopy. Optimized GYGAG(Ce) provides R(662 keV) =3.0%, for 0.05 cm3 size ceramics with Silicon photodiode readout, and R(662 keV) =4.6%, at 2 in3 size with PMT readout.
Sequence Detection Algorithms for PHY-Layer Sensing in Dynamic Spectrum Access Networks (2010)

Spectrum sensing is a critical function for enabling dynamic spectrum access (DSA) in wireless networks that utilize cognitive radio (CR). In DSA networks, unlicensed secondary users can gain access to a licensed spectrum band as long as they do not cause harmful interfere to primary users. Spectrum sensing is subject to errors in the form of false alarms and missed detections. False alarms cause spectrum under-use by secondary users, and missed detections cause interference to primary users. Although existing research has demonstrated the utility of a Markov chain for modeling the spectrum access pattern of primary users over time, little effort has been directed toward spectrum sensing based upon such models. In this paper, we develop general sequence detection algorithms for Markov sources in noise for spectrum sensing in DSA networks. We assign different Bayesian cost factors for missed detections and false alarms, and we show that a suitably modified forward-backward sequence detection algorithm is optimal in minimizing the detection risk. Two advanced sequence detection algorithms, the complete forward algorithm and the complete forward partial backward algorithm are introduced and their performances are compared as well. Along the way, we observe new fundamental limitations on sensing performance that we term the risk floor and the window length limitation of energy detection and coherent detection that arise from mismatch of their observation window with the PU's spectrum access pattern.
Joint Precoding and Multivariate Backhaul Compression for the Downlink of Cloud Radio Access Networks (2013)

This work studies the joint design of precoding and backhaul compression strategies for the downlink of cloud radio access networks. In these systems, a central encoder is connected to multiple multi-antenna base stations (BSs) via finite-capacity backhaul links. At the central encoder, precoding is followed by compression in order to produce the rate-limited bit streams delivered to each BS over the corresponding backhaul link. In current state-of-the-art approaches, the signals intended for different BSs are compressed independently. In contrast, this work proposes to leverage joint compression, also referred to as multivariate compression, of the signals of different BSs in order to better control the effect of the additive quantization noises at the mobile stations (MSs). The problem of maximizing the weighted sum-rate with respect to both the precoding matrix and the joint correlation matrix of the quantization noises is formulated subject to power and backhaul capacity constraints. An iterative algorithm is proposed that achieves a stationary point of the problem. Moreover, in order to enable the practical implementation of multivariate compression across BSs, a novel architecture is proposed based on successive steps of minimum mean-squared error (MMSE) estimation and per-BS compression. Robust design with respect to imperfect channel state information is also discussed. From numerical results, it is confirmed that the proposed joint precoding and compression strategy outperforms conventional approaches based on the separate design of precoding and compression or independent compression across the BSs.
A statistical correlation model for image retrieval (2001)

A bigram correlation model for image retrieval is proposed, which captures the semantic relationship among images in a database from simple statistics of users' relevance feedback information. It is used in the post-processing of image retrieval results such that more semantically related images are returned to the user. The algorithm is easy to implement and can be efficiently integrated into an image retrieval system to help improve the retrieval performance. Preliminary experimental results on a database of 100,000 images are very promising.
Electrochemical Protease Biosensor Based on Enhanced AC Voltammetry Using Carbon Nanofiber Nanoelectrode Arrays (2013)

We report an electrochemical method for measuring the activity of proteases using nanoelectrode arrays (NEAs) fabricated with vertically aligned carbon nanofibers (VACNFs). The VACNFs of ~150 nm in diameter and 3 to 5 μm in length were grown on conductive substrates and encapsulated in SiO<sub>2</sub> matrix. After polishing and plasma etching, controlled VACNF tips are exposed to form an embedded VACNF NEA. Two types of tetrapeptides specific to cancer-mediated proteases legumain and cathepsin B are covalently attached to the exposed VACNF tip, with a ferrocene (Fc) moiety linked at the distal end. The redox signal of Fc can be measured with AC voltammetry (ACV) at ~1 kHz frequency on VACNF NEAs, showing distinct properties from macroscopic glassy carbon electrodes due to VACNF's unique interior structure. The enhanced ACV properties enable the kinetic measurements of proteolytic cleavage of the surface-attached tetrapeptides by proteases, further validated with a fluorescence assay. The data can be analyzed with a heterogeneous Michaelis-Menten model, giving "specificity constant" <i>k<sub>cat</sub></i> /K<sub>m</sub> as (4.3 ± 0.8) × 10<sup>4</sup> M<sup>-1</sup>s<sup>-1</sup> for cathepsin B and (1.13 ± 0.38) × 10<sup>4</sup> M<sup>-1</sup>s<sup>-1</sup> for legumain. This method could be developed as portable multiplex electronic techniques for rapid cancer diagnosis and treatment monitoring.
Motion-Induced Phase Error Estimation and Correction in 3D Diffusion Tensor Imaging (2011)

A multishot data acquisition strategy is one way to mitigate B0 distortion and T2∗ blurring for high-resolution diffusion-weighted magnetic resonance imaging experiments. However, different object motions that take place during different shots cause phase inconsistencies in the data, leading to significant image artifacts. This work proposes a maximum likelihood estimation and k-space correction of motion-induced phase errors in 3D multishot diffusion tensor imaging. The proposed error estimation is robust, unbiased, and approaches the Cramer-Rao lower bound. For rigid body motion, the proposed correction effectively removes motion-induced phase errors regardless of the k-space trajectory used and gives comparable performance to the more computationally expensive 3D iterative nonlinear phase error correction method. The method has been extended to handle multichannel data collected using phased-array coils. Simulation and in vivo data are shown to demonstrate the performance of the method.
54) OMNJYIEW MOTIONLESS CAMERA ORIENTATION SYSTEM (1999)

ABSTRACT A device for omnidirectional image viewing providing pan- and-tilt orientation, rotation, and magnification within a hemispherical field-of-view that utilizes no moving parts. The imaging device is based on the effect that the image from a fisheye lens. which produces a circular image of at entire hemispherical field-of-view, which can be mathemati- cally corrected using high speed electronic circuitry. More specifically. an incoming fisheye image from any image acquisition source is captured in memory of the device, a transformation is performed for the viewing region of inter- est and viewing direction. and a corrected image is output as a video image signal for viewing. recording. or analysis. As a result. this device can accomplish the functions of pan, tilt, rotation. and zoom throughout a hemispherical field-of-view without the need for any mechanical mechanisms. The preferred embodiment of the image transformation device can provide corrected images at real-time rates. compatible with standard video equipment. The device can be used for any application where a conventional pan-and-tilt or orien- tation mechanism might be considered including inspection, monitoring, surveillance. and target acquisition.
Probing the Aglycon Promiscuity of an Engineered Glycosyltransferase (2008)

Eine süße Bibliothek: Zwei Varianten der Glycosyltransferase (GT) OleD (der Wildtyp (WT) und eine Dreifachmutante) katalysieren die Glycosylierung von über 70 Substraten, die Bildung von O-, S- und N-glycosidischen Bindungen sowie iterative Glycosylierungen. Unter den Substraten finden sich Nucleophile aus zahlreichen Naturstoff- und Wirkstoffklassen, von denen eine Teilnahme an GT-Reaktionen bisher nicht bekannt war. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
Hydrosilylation of terminal double bonds in polypropylene through reactive processing (1998)

Abstract The melt‐phase hydrosilylation of terminal double bonds in polypropylene (PP) was investigated. The double bonds were generated by peroxide initiated degradation of PP in an extruder or a batch mixer. For this purpose, an organic peroxide, Lupersol 101, was employed in concentrations of 0.5–5 wt%. A hydride‐terminated polydimethylsiloxane was employed as a model substance to investigate the feasibility of hydrosilylating the terminal double bonds of the degraded polypropylene. Reactive processing experiments were carried out in a hot press, a batch mixer, and a single screw extruder. Two different reaction mechanisms were used to initiate the hydrosilylation reaction: a radical chain addition mechanism and a platinum catalyzed mechanism using Karstedt's catlyst. For the radical mechanism, it was shown that catalytic amounts of a peroxide could initiate the addition of silanes to the double bonds of the degraded polypropylene. Furthermore, it was found that both reactions, degradation and hydrosilylation, could be performed simultaneously. For the catalytic mechanism, the required stabilization of the platinum colloid formed in this mechanism was accomplished by adding t‐butylhydroperoxide as a cocatalyst. This melt‐phase hydrosilylation route may be used to produce terminally functionalized polypropylenes, and a case study involving the terminal attachment of a styrene functionality was examined.
Ultrafast Protein Determinations Using Microwave Enhancement (1996)

In this chapter, we describe modifications of existing protein assays that take advantage of microwave irradiation to reduce assay incubation times from the standard 15–60 min down to just seconds (). Adaptations based on two standard protein assays will be described: 1. The classic method of Lowry et al. (ref. and (see Chapter 2), which involves intensification of the biuret reaction through the addition of Folin-Ciocalteau phenol reagent; and 2. The recently developed method of Smith et al. (), which involves intensification of the biuret assay through the addition of bicinchoninic acid (BCA) (see Chapter 3).