gebhart/patrepeval huggingface dataset:
Femtosecond laser ablation particle introduction to a liquid sampling-atmospheric pressure glow discharge ionization source (2012)

This work describes the use of a compact, liquid sampling–atmospheric pressure glow discharge (LS-APGD) ionization source to ionize metal particles within a laser ablation aerosol. Mass analysis was performed with a Thermo Scientific Exactive Mass Spectrometer which utilizes an orbitrap mass analyzer capable of producing mass resolution exceeding m/Δm > 160,000. The LS-APGD source generates a low-power plasma between the surface of an electrolytic solution flowing at several μl min−1 through a fused silica capillary and a counter electrode consisting of a stainless steel capillary employed to deliver the laser ablation particles into the plasma. Sample particles of approximately 100 nm were generated with an Applied Spectra femtosecond laser located remotely and transported through 25 meters of polyurethane tubing by means of argon carrier gas. Samples consisted of an oxygen free copper shard, a disk of solder, and a one-cent U.S. coin. Analyte signal onset was readily detectable relative to the background signal produced by the carrier gas alone. The high mass resolution capability of the orbitrap mass spectrometer was demonstrated on the solder sample with resolution exceeding 90,000 for Pb and 160,000 for Cu. In addition, results from a laser ablation depth-profiling experiment of a one cent coin revealed retention of the relative locations of the ∼10 μm copper cladding and zinc rich bulk layers.
Cleavage of caspase family members by granzyme B: a comparative study <i>in vitro</i> (1997)

Abstract The aspartase granzyme B is one of the major components of the granules involved in cell killing by cytotoxic T lymphocytes. Granzyme B has been shown to activate the apoptotic death pathway in the target cell, and this involves activation of members of the caspase (CASP) protein family. Therefore, activational cleavage of mouse (m) CASP proforms by granzyme B was examined in vitro. CASP can be subdivided in the CASP‐1 (interleukin‐1β‐converting enzyme; ICE) subfamily, the CASP‐2 (Ich1) subfamily, and the CASP‐3 (CPP32) subfamily. Our results reveal that the proforms of the CASP‐3 subfamily members mCASP‐3 and mCASP‐7 are hydrolyzed by granzyme B, while proforms of CASP‐2 and CASP‐1 subfamily members are not directly cleaved. Only one CASP‐3 subfamily member, pro‐mCASP‐6, was not proteolytically cleaved by granzyme B. These results indicate that two members of the CASP‐3 subfamily, but no others, become activated by granzyme B.
Glycolipids as a source of polyols for the design of original linear and cross-linked polyurethanes (2012)

Two novel sugar-based fatty ester polyols were synthesized by selective transesterification of epoxidized methyl or ethyl oleate with unprotected methyl α-D-glucopyranoside and sucrose respectively, followed by hydrolysis of the epoxide moiety. The so-formed polyols were then used as polyurethane (PU) precursors in the polyaddition with isophorone diisocyanate (IPDI) in the presence of dibutyl tin dilaurate (DBTDL) as a catalyst. Interestingly, the reactivity of the hydroxyl functions attached to the sugar and to the fatty ester chain moieties respectively could be discriminated with respect to the solvent used, enabling the synthesis of either linear or cross-linked PUs. The linear PUs were studied by means of FTIR, 1H NMR spectroscopy and size exclusion chromatography, SEC. The thermo-mechanical properties of these original PUs bearing pendant or intramolecular sugar units were also analyzed by differential scanning calorimetry, DSC.
Optical Sensor‐Based Algorithm for Crop Nitrogen Fertilization (2005)

Abstract Nitrogen (N) fertilization for cereal crop production does not follow any kind of generalized methodology that guarantees maximum nitrogen use efficiency (NUE). The objective of this work was to amalgamate some of the current concepts for N management in cereal production into an applied algorithm. This work at Oklahoma State University from 1992 to present has focused primarily on the use of optical sensors in red and near infrared bands for predicting yield, and using that information in an algorithm to estimate fertilizer requirements. The current algorithm, “WheatN.1.0,” may be separated into several discreet components: 1) mid‐season prediction of grain yield, determined by dividing the normalized difference vegetative index (NDVI) by the number of days from planting to sensing (estimate of biomass produced per day on the specific date when sensor readings are collected); 2) estimating temporally dependent responsiveness to applied N by placing non‐N‐limiting strips in production fields each year, and comparing these to the farmer practice (response index); and 3) determining the spatial variability within each 0.4 m2 area using the coefficient of variation (CV) from NDVI readings. These components are then integrated into a functional algorithm to estimate application rate whereby N removal is estimated based on the predicted yield potential for each 0.4 m2 area and adjusted for the seasonally dependent responsiveness to applied N. This work shows that yield potential prediction equations for winter wheat can be reliably established with only 2 years of field data. Furthermore, basing mid‐season N fertilizer rates on predicted yield potential and a response index can increase NUE by over 15% in winter wheat when compared to conventional methods. Using our optical sensor‐based algorithm that employs yield prediction and N responsiveness by location (0.4 m2 resolution) can increase yields and decrease environmental contamination due to excessive N fertilization.
<i>Trichomonas vaginalis</i>: observation of coexistence of multiple viruses in the same isolate (2002)

Trichomonas vaginalis is a flagellated, parasitic protozoan that inhabits the urogenital tract of humans. Some isolates of T. vaginalis are infected with a double-stranded RNA (dsRNA) virus, which was described in the literature as homogeneous icosahedral viral particles with an isometric symmetry and 33 nm in diameter. This study examined in detail the viral particles in T. vaginalis isolate 347 and describes a heterogeneous population of viral particles. The different dsRNA viruses were only observed after a change in the technique. The sample was prepared by the negative staining carbon-film method directly onto freshly cleft mica. The detected viruses ranged in size from 33 to 200 nm. Among the shapes observed were filamentous, cylindrical, and spherical particles. These results show that T. vaginalis may be a reservoir for several different dsRNA viruses simultaneously.
Enhancing Dynamic Symbolic Execution by Automatically Learning Search Heuristics (2019)

We present a technique to automatically generate search heuristics for dynamic symbolic execution. A key challenge in dynamic symbolic execution is how to effectively explore the program's execution paths to achieve high code coverage in a limited time budget. Dynamic symbolic execution employs a search heuristic to address this challenge, which favors exploring particular types of paths that are most likely to maximize the final coverage. However, manually designing a good search heuristic is nontrivial and typically ends up with suboptimal and unstable outcomes. The goal of this paper is to overcome this shortcoming of dynamic symbolic execution by automatically learning search heuristics. We define a class of search heuristics, namely a parametric search heuristic, and present an algorithm that efficiently finds an optimal heuristic for each subject program. Experimental results with industrial-strength symbolic execution tools (e.g., KLEE) show that our technique can successfully generate search heuristics that significantly outperform existing manually-crafted heuristics in terms of branch coverage and bug-finding.
A 400-Ms/s frequency translating bandpass sigma-delta modulator (1999)

A bandpass /spl Sigma/-/spl Delta/ modulator is described in this paper that uses frequency translation inside the /spl Sigma/-/spl Delta/ modulator loop to take advantage of the attributes of both continuous-time and discrete-time circuits. A CMOS direct-conversion modulator digitizes a 200 kHz intermediate-frequency signal centered at 100 MHz and produces baseband I/Q outputs with a peak signal-to-noise ratio of 54 dB. Images due to I/Q mismatches are suppressed by 50 dB. This 0.35-/spl mu/m digital CMOS chip operates from a 2.7/3.3-V supply, dissipates 330 mW, and occupies 3.2 mm/sup 2/.
Purification and characterization of endo-.ALPHA.-N-acetylgalactosaminidase from Alcaligenes sp. (1988)

A gram negative bacterium isolated from soil was found to produce an endo-α-N-acetylgalactosaminidase in culture. The microorganism was identified as Alcaligenes sp. from various bacteriological characteristics. The enzyme was purified from the culture fluid by fractionation with ammonium sulfate, and column chromatographies on DEAE-Sephadex A-50 and hydroxylapatite. The molecular weight of the enzyme was estimated to be 160, 000 by gel filtration and SDS-polyacrylamide gel electrophoresis. The optimum pH was found to be 4.5 and the stable pH range was 4.5-6.5. The Km values were 3.7mM and 3.2mM with asialofetuin and asialo κ-casein glycopeptide as substrates, respectively. The enzyme released the disaccharide, Galβ1→3GalNAc, from glycoproteins possessing serine or threonine O-glycosidic linkages. The enzyme production was highly induced by porcine gastric mucin added to the medium.
The real-time dose measurement scintillating fiber array for intravascular brachytherapy procedures (2003)

Intravascular brachytherapy using catheter based high dose rate /spl beta/ sources has taken nowadays an important role in interventional cardiology to combat in-stent restenosis following percutaneous transluminal coronary angioplasty. At the present time, there is no detector system which can record accurate quantitative doses and spatial information in real time for intravascular brachy therapy. This is partially because of the short-range of the low energy beta emission of /sup 32/P (average energy of 690 keV) and /sup 90/Sr//sup 90/Y (average energy of 930 keV) and the resolution limitation of existing extrapolation chambers and radiochromatic-dye films (currently the preferred method used). However, relatively high non-uniformity, which occurs at the stepping region due to excessive gapping or overlapping between steps, might result in in-stent restenosis or detrimental to the coronary vascular structure due to significant discrepancies between prescribed and delivered doses. We have developed a scintillating fiber based beta detector prototype which will permit: (i) extracting in real time of accurate dose measurements of the radioactive emitter in 2D or 3D; (ii) address the junction/stepping problem in a reliable fashion; (iii) allow extraction of information on the (in)homogeneity of the radioactive source (if any); and (iv) provide a quick feedback to radio-therapists for a fast re-adjustment of the radiation exposure for patient treatments. It is composed of an array of 3 /spl times/ 3 mm/sup 2/ scintillating fibers optically coupled to photo-multiplier tubes for photon-to-current conversion. A CAMAC LabView based data acquisition system is used for data collection, histogramming and data analysis. A Geant4 Monte Carlo simulation was also specially developed for this detector to provide the necessary tool to investigate the various capabilities of such devices.
Spatial Localization in NMR Spectroscopy <i>in Vivo</i> (1987)

Spatial localization techniques are necessary for in vivo NMR spectroscopy involving heterogeneous organisms. Localization by surface coil NMR detection alone is generally inadequate for deep-lying organs due to contaminating signals from intervening surface tissues. However, localization to preselected planar volumes can be accomplished using a single selective excitation pulse in the presence of a pulsed magnetic field gradient, yielding depth-resolved surface coil spectra (DRESS). Within selected planes, DRESS are spatially restricted by the surface coil sensitivity profiles to disk-shaped volumes whose radii increase with depth, notwithstanding variations in the NMR signal density distribution. Nevertheless, DRESS is a simple and versatile localization procedure that is readily adaptable to spectral relaxation time measurements by adding inversion or spin-echo refocusing pulses or to in vivo solvent-suppressed spectroscopy of proton (1H) metabolites using a combination of chemical-selective RF pulses. Also, the spatial information gathering efficiency of the technique can be improved to provide simultaneous acquisition of spectra from multiple volumes by interleaving excitation of adjacent planes within the normal relaxation recovery period. The spatial selectivity can be improved by adding additional selective excitation spin-echo refocusing pulses to achieve full, three-dimensional point resolved spectroscopy (PRESS) in a single excitation sequence. Alternatively, for samples with short spin-spin relaxation times, DRESS can be combined with other localization schemes, such as image-selected in vivo spectroscopy (ISIS), to provide complete gradient controlled three-dimensional localization with a reduced number of sequence cycles.
Precise and efficient cleavage of recombinant fusion proteins using mammalian aspartic proteases (2003)

Expression of recombinant proteins as translational fusions is commonly employed to enhance stability, increase solubility and facilitate purification of the desired protein. In general, such fusion proteins must be cleaved to release the mature protein in its native form. The usefulness of the procedure depends on the efficiency and precision of cleavage and its cost per unit activity. We report here the development of a general procedure for precise and highly efficient cleavage of recombinant fusion proteins using the protease chymosin. DNA encoding a modified pro-peptide from bovine chymosin was fused upstream of hirudin, carp growth hormone, thioredoxin and cystatin coding sequences and expressed in a bacterial Escherichia coli host. Each of the resulting fusion proteins was efficiently cleaved at the junction between the pro-peptide and the desired protein by the addition of chymosin, as determined by activity, N-terminal sequencing and mass spectrometry of the recovered protein. The system was tested further by cleavage of two fusion proteins, cystatin and thioredoxin, sequestered on oilbody particles obtained from transgenic Arabidopsis seeds. Even when the fusion protein was sequestered and immobilized on oilbodies, precise and efficient cleavage was obtained. The precision, efficiency and low cost of this procedure suggest that it could be used in larger scale manufacturing of recombinant proteins which benefit from expression as fusions in their host organism.
Utilization of mechanical quadrature in silicon MEMS vibratory gyroscope to increase and expand the long term in-run bias stability (2014)

We report a new approach for improvement of the long term in-run bias stability of Coriolis vibratory gyroscopes. The approach is based on utilization of the mechanical quadrature error in gyroscopes to compensate for variation in system parameters. The proposed approach was validated by a silicon Quadruple Mass Gyroscope, with the natural frequency of 3 kHz, frequency mismatch of <;0.5 Hz, and isotropic quality factor of 950, packaged without getter. The algorithm is described and experimentally demonstrated in this paper, showing a bias stability of 0.1 deg/hr after 300 seconds, and importantly, retaining that value for over 3 hours of the integration time.
Applications of femtosecond laser induced Bragg gratings in silica and non-silica based optical fibers (2010)

Since its development in 2003, the technique of Bragg grating inscription using an ultrafast infrared laser and a phase mask has proven to be far more versatile than the standard ultraviolet laser approach. The ultrafast IR laser-based process allows for the creation of grating structures in glassy and crystalline material waveguides that are not typically UV-photosensitive, thereby creating new applications for Bragg gratings where the use of UV-photosensitive silica fibers is not possible. In this paper we will review the studies that have been performed at the Communications Research Centre Canada on the applications of the ultrafast laser technique to fabricate gratings in various optical fibers and waveguides.
Multi-band small-scale fading mitigation at UWB localization receivers in dense multipath channels (2017)

Despite the intrinsic temporal resolution of Impulse Radio - Ultra Wideband (IR-UWB) signals, specific low-power and low-complexity integrated receiver architectures devoted to long-range localization are still structurally subject to severe intra-channel interference caused by dense colliding multipath components (MPCs). In order to restore the MPC tracking potential of such receivers and hence ultimately, to improve MPC-aided localization, we propose to opportunistically combine channel estimations performed in multiple sub-bands, which were initially intended for multiple access. First, we develop two simplified 2-path models interpreting the local interference phenomena in terms of both dynamics and patterns frequency, while illustrating the expected benefits from combined multiband channel estimations. Then, we evaluate the capability to capture the energy of the various MPCs independently through realistic simulations based on IEEE 802.15.4a channel models. Finally, we use the proposed method to feed an MPC-based mobile tracking algorithm, specifically designed for generalized non-visibility situations (i.e., with respect to anchors). Other simulations then show that our proposal overcomes conventional pre-filtering methods in terms of final localization performances.
Class of cyclic-based estimators for frequency-offset estimation of OFDM systems (2000)

We present a new class of blind cyclic-based estimators for carrier frequency-offset and symbol-timing error estimation of orthogonal frequency-division multiplexing (OFDM) systems. The proposed approach exploits the properties of the cyclic prefix subset to reveal the synchronization parameters in the likelihood function of the received vector. A new likelihood function for the joint timing and frequency-offset estimation is derived, which globally characterizes the estimation problem. The resulting probabilistic measure is used to develop three classes of unbiased estimators, namely, maximum-likelihood, minimum variance unbiased, and moment estimator. In comparison to the previously proposed methods, the proposed estimators in this study are computationally and statistically efficient, which makes the estimators more attractive for real-time applications. The performance of the estimators is assessed by simulation for an OFDM system.
Near-Field Chipless-RFID System With High Data Capacity for Security and Authentication Applications (2017)

A high data capacity chipless radio frequency identification (chipless-RFID) system, useful for security and authentication applications, is presented in this paper. Reading is based on the near-field coupling between the tag, a chain of identical split-ring resonators (SRRs) printed on a (typically flexible) dielectric substrate (e.g., liquid crystal polymer, plastic, and paper), and the reader. Encoding is achieved by the presence or absence of SRRs at predefined (equidistant) positions in the chain, and tag identification (ID) is based on sequential bit reading. Namely, the tag must be longitudinally displaced, at short distance, over the reader, a microstrip line loaded with an SRR and fed by a harmonic signal. By this means, the harmonic signal is amplitude modulated, and the (ID) code is contained in the envelope function, which can be obtained by means of an envelope detector. With this system, tag reading requires proximity with the reader, but this is not an issue in many applications within the domain of security and authentication (e.g., secure paper for corporate documents and certificates). Several circularly shaped 40-bit encoders (implemented in a commercial microwave substrate), and the corresponding reader, are designed and fabricated as proof-of-concept demonstrators. Strategies for programming the tags and a first proof-of-concept chipless-RFID tag fabricated on plastic substrate through inkjet printing are included in this paper.
MutS HOMOLOG1 Is a Nucleoid Protein That Alters Mitochondrial and Plastid Properties and Plant Response to High Light  (2011)

Mitochondrial-plastid interdependence within the plant cell is presumed to be essential, but measurable demonstration of this intimate interaction is difficult. At the level of cellular metabolism, several biosynthetic pathways involve both mitochondrial- and plastid-localized steps. However, at an environmental response level, it is not clear how the two organelles intersect in programmed cellular responses. Here, we provide evidence, using genetic perturbation of the MutS Homolog1 (MSH1) nuclear gene in five plant species, that MSH1 functions within the mitochondrion and plastid to influence organellar genome behavior and plant growth patterns. The mitochondrial form of the protein participates in DNA recombination surveillance, with disruption of the gene resulting in enhanced mitochondrial genome recombination at numerous repeated sequences. The plastid-localized form of the protein interacts with the plastid genome and influences genome stability and plastid development, with its disruption leading to variegation of the plant. These developmental changes include altered patterns of nuclear gene expression. Consistency of plastid and mitochondrial response across both monocot and dicot species indicate that the dual-functioning nature of MSH1 is well conserved. Variegated tissues show changes in redox status together with enhanced plant survival and reproduction under photooxidative light conditions, evidence that the plastid changes triggered in this study comprise an adaptive response to naturally occurring light stress.
Zero sequence method for energy recovery from a variable-speed wind turbine generator (2001)

An innovative power conversion system to convert energy from a variable-frequency wind-powered induction generator to a fixed frequency output is presented. A standard six-switch DC link current regulated pulse width modulated (CRPWM) inverter is simultaneously modulated with two current components. A three-phase balanced current component at the induction generator's optimum operating frequency transfers energy from the generator to the converter. A single phase zero sequence current component at a fixed 60 Hz frequency transfers energy from the converter through a zero sequence filter to the load. Unity power factor output is shown both in simulation and experiment, though any arbitrary power factor output may be readily commanded. Maximum power capture for a variable-speed wind turbine is achieved using proven control techniques. This method uses only half of the active power switching devices of conventional conversion methods. Simulation and experimental verification are shown.
Generation of THz and IR radiation in DAST crystals (2006)

Short THz pulses are commonly generated through the optical rectification of ultrashort laser pulses in nonlinear optical crystals. Our purpose is to discuss the controllability of the THz spectrum emitted from the polar organic salt DAST (4-N,N-dimethylamino-4-N-methyl stilbazolium tosylate) and also the efficiency of the THz generation. It does not only depend on different experimental parameters such as duration of the laser pulse and crystal thickness, but is also affected by absorption and dispersion caused by several resonances of the crystal in the THz range.