gebhart/patrepeval huggingface dataset:
Purification of L-Isoleucyl t-rna Synthetase by Affinity Chromatography (1974)

Abstract L-Isoleucyl t-RNA synthetase was purified to 97% purity in a single step by affinity chromatography on a column carrying L-isoleucinyl 5′-adenylate as the insolubilized ligand. Recovery was 50–60%.
Macromol. Biosci. 1/2009 (2008)

Cover: The cover art illustrates the shape‐memory effect of a multiblock copolymer with poly( ε ‐caprolactone) and poly(iso‐butylmorpholin dione) segments on two levels: the macroscopic shape recovery from the temporary shape (“stripe”) at 25°C (blue colour) to the permanent shape (“corkscrew”) at 60°C (red colour) as well as the changes of the morphology represented by AFM phase images (back image and small inset). Further details can be found in the article by Y. Feng, M. Behl, S. Kelch, A. Lendlein * on page 45.
Cohesion and Stability of Metal Nanowires: A Quantum Chaos Approach (2002)

A remarkably quantitative understanding of the electrical and mechanical properties of metal wires with a thickness on the scale of a nanometer has been obtained within the free-electron model using semiclassical techniques. Convergent trace formulas for the density of states and cohesive force of a narrow constriction in an electron gas, whose classical motion is either chaotic or integrable, are derived. Mode quantization in a metallic point contact or nanowire leads to universal oscillations in its cohesive force, whose amplitude depends only on a dimensionless quantum parameter describing the crossover from chaotic to integrable motion, and is of order 1nN, in agreement with experiments on gold nanowires. A linear stability analysis shows that the classical instability of a long wire under surface tension can be completely suppressed by quantum effects, leading to stable cylindrical configurations whose electrical conductance is a magic number 1, 3, 5, 6,... times the conductance quantum, in accord with recent results on alkali metal nanowires.
Novel<i>S</i>-Xanthenyl Protecting Groups for Cysteine and Their Applications for the<i>N</i><sup>α</sup>-9-Fluorenylmethyloxycarbonyl (Fmoc) Strategy of Peptide Synthesis<sup>1-3</sup> (1997)

The 9H-xanthen-9-yl (Xan) and 2-methoxy-9H-xanthen-9-yl (2-Moxan) groups can be introduced onto sulfhydryl functions by S-alkylation reactions involving the corresponding xanthydrols, plus trifluoroacetic acid (TFA) as catalyst. Conversely, these groups are removed rapidly by acid in the presence of appropriate silane or thiol scavengers. The 3-methoxy-9H-xanthen-9-yl (3-Moxan) derivative was also studied, but abandoned for several reasons including challenging synthesis, excessive lability to acid, and insufficient stability in the presence of base. The Nα-9-fluorenylmethyloxycarbonyl (Fmoc), S-Xan or 2-Moxan-protected cysteine derivatives were prepared and applied to the solid-phase syntheses of several model peptides. Selective removal of S-Xan and S-2-Moxan groups, while retaining tris(alkoxybenzyl)amide (PAL) anchoring, is best accomplished with TFA−CH2Cl2−Et3SiH (1:98.5:0.5), 25 °C, 2 h. Alternatively, oxidative deprotection of S-Xan or S-2-Moxan with iodine (10−20 equiv) or thallium(III) tris(trifluoroacetate) [Tl(tfa)3] (1−3 equiv) to provide disulfides can be carried out on peptide substrates both in solution and while polymer-bound. Compared to established chemistries with the acid-labile and oxidizable S-triphenylmethyl (Trt) group, S-Xan and S-2-Moxan gave equal or superior results in terms of peptide purities (including no detectable tryptophan alkylation) and overall yields.
Place Exchange Reactions of Alkyl Thiols on Gold Nanoparticles (2006)

The kinetics and equilibrium position of place exchange (alkylthiol-for-alkylthiol) reactions of gold nanoparticles are reported. These reactions were monitored via a gas chromatography analysis of structurally similar incoming and outgoing alkylthiols, as a function of time. The place exchange reactions described here proceed to an equilibrium position, where Keq approximately 1. The product-time data follow Langmuir diffusion kinetics.
Combined inhibitory effect of lactoferrin and lactoperoxidase system on the viability of <i>Streptococcus mutans</i>, serotype c (1991)

We have studied the effects of iron-free lactoferrin (apo LF) and lactoperoxidase system (lactoperoxidase, LP/SCN-/H2O2), separately and together, on the viability of Streptococcus mutans (serotype c) in vitro. The bacteria were incubated in buffered KCl (pH 5.5) with and without the above components which were used at concentrations normally present in human saliva. Both apo LF and LP-system had a bactericidal effect against S. mutans at low pH. Together they showed an additive, but not a synergistic, antibacterial effect against S. mutans. Apo LF enhanced the LP enzyme activity but decreased the yield of the antimicrobial component, hypothiocyanite (HOSCN/OSCN-), when incorporated into the reaction mixtures. This decrease, which was most pronounced at low pH, was due to an LP-independent reaction between apo LF and HOSCN/OSCN-. Our study indicates that the LP-system and apo LF can be combined to combat oral S. mutans.
Data reduction via adaptive sampling (2002)

Data reduction is an important issue in the field of data mining. This article describes a new method for selecting a subset of data from a large dataset. A simplified chi-square criterion is proposed for measuring the goodness-of-fit between the distributions of the reduced and full data sets. Under this criterion, the data reduction problem can be formulated as a binary quadratic program and a tabu search technique is used in the search/optimization process. The procedure is adaptive in that it involves not only random sampling but also deterministic search guided by the results of the previous search steps. The method is applicable primarily to discrete data, but can be extended to continuous data as well. An experimental study that compares the proposed method with simple random sampling on a number of simulated and real world datasets has been conducted. The results of the study indicate that the distributions of the samples produced by the proposed method are significantly closer to the true distribution than those of random samples.
Endothelial functional responses and increased vascular permeability induced by polycations. (1988)

Polycations such as poly-L-lysine powerfully stimulated cultured endothelial cells from pig aorta to release prostacyclin and cytoplasmic purines in a dose (charge)-dependent and molecular weight (size) dependent manner. Neutral or anionic polymers were inactive. Qualitatively similar findings were made in vivo where poly-L-lysine induced charge and size-dependent local edema formation after intradermal injection in the rabbit. Pretreatment of cultured endothelium with heparin or trypsin (but not neuraminidase) effectively reduced the response of the cells to subsequent exposure to poly-L-lysine suggesting an interaction of polycations with integral membrane proteins. Edema responses to poly-L-lysine were reduced in the presence of indomethacin suggesting that generation of an endogenous vasodilator prostaglandin, perhaps endothelial cell-derived, was an important component of the response. Poly-L-lysine-induced edema formation was not dependent on endogenous histamine release but was reduced by locally administered trasylol while soybean trypsin inhibitor failed to inhibit the response. Our results indicate that polycations such as poly-L-lysine can induce responses of vascular endothelium in vitro and in vivo and that the effects are not only charge-related but are also dependent on the size of the polycation. We suggest that naturally occurring polycations such as those derived from leukocytes and platelets may play an important role in various pathologic processes and that this may be closely related to their size.
Model system evaluating fluorescein‐labeled microbeads as internal standards to calibrate fluorescence intensity on flow cytometers (1989)

Fluorescence intensity calibration was evaluated in a model system for flow cytometers using commercially available fluorescein-labeled microbeads as internal standards and stabilized fluoresceinated thymus cell nuclei (Fluorotrol) as surrogates for stained mononuclear cells. Spectrophotometrically determined calibration values for the microbeads were used to generate a standard curve that converted green fluorescence histogram channels into molecular equivalents of soluble fluorescein (MESF). In 19 analyses repeated during a single run, the coefficients of variation (CVs) for the derived MESF values on both dimly and brightly stained Fluorotrol populations were less than 2%. In 26 separate determinations over 14 weeks, the CVs of the derived MESF values were less than 3%. The MESF values of the dim and bright Fluorotrol populations derived from the microbead standard curves were both about 50% lower than those determined by direct spectrophotometric analysis of Fluorotrol. The analytical imprecision of fluorescence intensity measurements in this idealized model system has a CV less than 3%, and the analytical inaccuracy shows that calibration in MESF units remains uncertain over about a two-fold range.
An efficient ASIC architecture for real-time edge detection (1989)

An efficient application-specific architecture is presented for a real-time edge detection system. The architecture is based on the cooperating-data-path model, which allow both the throughput and the area to be optimized for this recursive algorithm. Careful scheduling of the operations on the partly parallel, partly shared hardware has allowed the load to be balanced on each of the four data paths. In this way, the inherently high degree of concurrency in the algorithm has been effectively exploited in the parallel pipelined hardware. The layout of the data paths has been generated by means of powerful CAD tools and the use of a parameterizable functional-building-block library. The corresponding global controller has been partitioned in order to optimize the critical path. This has increased the achievable clock rate even further, up to 10 MHz. The stringent I/O requirements have been taken into account. The resulting ASIC has been verified by register-transfer simulation. It is more than twice as fast as existing designs. The effectiveness of the cooperating-data-path model is thus clearly substantiated by this large, practical test vehicle.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Hydroxylamine Chemistry. IV. O-Aralkylhydroxylamines (1964)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydroxylamine Chemistry. IV. O-AralkylhydroxylaminesE. L. Schumann, R. V. Heinzelman, M. E. Greig, and W. VeldkampCite this: J. Med. Chem. 1964, 7, 3, 329–334Publication Date (Print):May 1, 1964Publication History Published online1 May 2002Published inissue 1 May 1964https://pubs.acs.org/doi/10.1021/jm00333a017https://doi.org/10.1021/jm00333a017research-articleACS PublicationsRequest reuse permissionsArticle Views351Altmetric-Citations17LEARN 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-Alertsclose Get e-Alerts
Wavelength conversion by quasi-phase-matched difference frequency generation in AlGaAs waveguides (1995)

WDM networks require wavelength conversions to avoid blocking and to provide scalability.1 Wavelength conversion techniques utilizing gain-saturation in semiconductor optical amplifiers provide a relatively simple wavelength cross-connect architecture, but a signal deterioration due to large noise, positive chirps, and poor contrast ratios is a serious problem for high-capacity WDM network applications. Difference frequency generation (DFG), on the other hand, offers a transparent wavelength conversion with quantum-noise limited operation. Its chirp-reversal and multi-wavelength conversion capabilities can also impact future high-capacity WDM network applications.
Mitochondrial Thioredoxin-2 Has a Key Role in Determining Tumor Necrosis Factor-α–Induced Reactive Oxygen Species Generation, NF-κB Activation, and Apoptosis (2006)

Tumor necrosis factor-alpha (TNF-alpha) is a cytokine that is involved in numerous pathologies, in part through stimulation of the mitochondrial production of reactive oxygen species (ROS). Previous studies show that in addition to mitochondrial superoxide dismutase- and glutathione-dependent systems, mitochondria also contain thioredoxin-2 (Trx2), an antioxidant protein that can detoxify ROS. The purpose of this study was to determine whether Trx2 protects against oxidative damage triggered by TNF-alpha. After a 30-min treatment in HeLa cells, TNF-alpha (5-40 ng/ml) oxidized Trx2 but not cytoplasmic Trx1. Preferential, significant Trx2 oxidation occurred within 10 min of TNF-alpha treatment. Moreover, overexpression of Trx2, but not Trx1, decreased TNF-alpha-induced ROS generation, suggesting mitochondrial compartmentation of ROS production and subsequent specific detoxification by Trx2, not Trx1. Overexpression of Trx2 or the active-site mutant C93S Trx2 was used to evaluate their downstream effects following TNF-alpha stimulation. Results showed that nuclear translocation of NF-kappaB was inhibited with Trx2 overexpression but not with the dominant negative active-site mutant C93S Trx2. Moreover, when cotransfected with a NF-kappaB-luciferase reporter and then treated with TNF-alpha, NF-kappaB activity was significantly attenuated with Trx2 overexpression but not with C93S Trx2 expression. Trx2 overexpression, but not C93S Trx2, significantly inhibited TNF-alpha-induced apoptosis as measured by terminal dUTP nick-end labeling assay. These findings support the interpretation that mitochondrial-generated ROS is a principal component in TNF-alpha-induced effects and that Trx2 blocks TNF-alpha-induced ROS generation and downstream NF-kappaB activation and apoptosis.
International Competitiveness in Wheat Production (1989)

Eleven cases of basal cell carcinoma of the vulvar skin are reported. There was fairly close correlation between the histologic type and the gross appearance of the lesion. The average age of the patients was 59 years, and the presenting complaint was usually that of a nodule with associated irritation or pruritus. All patients were treated surgically and none have had recurrent or metastatic disease; six patients have been followed for 12 to 25 years. The treatment of choice is wide local excision. One tumor was of particular interest in that it represented a carcinomatous change in a pre-existing premalignant fibroepithelial tumor. Basal cell carcinoma of the skin must be distinguished from adenoid cystic (basal cell) carcinoma of vestibular glands, which is a more aggressive neoplasm and which metastasizes by the lymphatic and blood vascular systems.
A WLAN direct up-conversion mixer with automatic image rejection calibration (2005)

A direct upconverter for 5 to 6 GHz WLAN is presented that includes circuitry for automatic output spectrum calibration. For calibration, the RF signal is down-converted by reusing the up-conversion mixers, making the up- and down-conversion errors correlated. The transmit errors are determined based on only low-frequency measurements. The realized mixer achieves >40 dB image rejection.
Coordination chemistry of dihydrogen (1993)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoordination chemistry of dihydrogenD. M. Heinekey and Warren J. OldhamCite this: Chem. Rev. 1993, 93, 3, 913–926Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue 1 May 1993https://pubs.acs.org/doi/10.1021/cr00019a004https://doi.org/10.1021/cr00019a004research-articleACS PublicationsRequest reuse permissionsArticle Views2228Altmetric-Citations545LEARN 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-Alertsclose Get e-Alerts
Synthesis and Characterization of PMMA Nanocomposites by Suspension and Emulsion Polymerization (2001)

PMMA-layered silicate nanocomposites were prepared by in-situ suspension polymerization and emulsion polymerization. For the suspension polymerization, the silicate layers were dispersed individually in water, and we speculate that they are adsorbed on the surface of monomer droplets. For the emulsion polymerization, the nanocomposite was obtained by adding an aqueous dispersion of layered silicate into the polymer emulsion. Wide-angle X-ray diffraction (WAXD) and atom force microscopy (AFM) were used to characterize the structures of the nanocomposites. Analysis of samples from emulsion and suspension polymerization was consistent with an exfoliated structure; after melt pressing, WAXD analysis indicated that both intercalated and exfoliated structures were observed. The exfoliated structure was preserved when organic modifiers that produced tethered polymer chains were used. Compared to a PMMA macrocomposite, the nanocomposites prepared by these methods display glass transition temperatures that are up to 15 °C higher and thermal degradation temperatures that are up to 60 °C higher.
Intermodulation distortion in 48 TV channel FM-FDM optical transmission (1991)

The effect of dispersive fibers on multichannel FM video transmission characteristics is experimentally investigated. A directly modulated 1.5 mu m distributed feedback laser diode (DFB-LD) and a LiNbO/sub 3/ external modulator with a continuous-wave (CW) 1.55 mu m DFB-LD are used as optical signal sources. When the 1.3 mu m single-mode fiber (SMF) is used, directly modulated DFB-LDs suffer from second-and third-order intermodulation distortion (IMD). The external modulator realizes good transmission characteristics irrespective of the fiber's dispersion value. This means that external modulators can realize multichannel FM television signal transmission systems that use the standard 1.3 mu m SMF already installed in fiber optic subscriber loops.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Nitric Oxide Scavenging, Alone or with Nitric Oxide Synthesis Inhibition, Modulates Vascular Hyporeactivity in Rats with Intraperitoneal Sepsis (2002)

Elevated levels of nitric oxide (NO) may be a primary cause of the vascular hyporeactivity (vasoplesia) and refractory hypotension in sepsis. This study was initiated to determine the efficacy of NO scavenging with acellular hemoglobin (Hb) solution in modulating sepsis-mediated vasoplesia. Male Sprague Dawley rats were subjected to sepsis by cecal ligation and puncture (CLP). Twenty-four hours post-CLP, the animals were randomly assigned to one of four groups (n = 5-6 each) and given an intravenous injection of 0.5 mL bovine serum albumin (BSA; 5 g/dL), 0.5 mL human Hb (7g/dL), 50 microL Nomega-nitro L-arginine methyl ester (NAME; 1 M), or both Hb and NAME. Blood pressure (BP), cardiac output, systemic vascular resistance, and vascular reactivity (VR) to norepinephrine (NE; 40 ng/Kg) were assessed before and after an experimental treatment. In some animals, inducible NO synthase (iNOS) mRNA expression was assessed in selected tissue samples harvested at the conclusion of experiment using a reverse transcription-polymerase chain reaction (RT-PCR) method. Treatment with Hb, NAME, or NAME + Hb elicited a significant improvement in mean BP and VR compared with the control (BSA) group (P < 0.05, analysis of variance and Neuman-Keuls tests). Tissue samples from 24-h CLP rats clearly exhibited iNOS gene expression; higher iNOS gene expression in the intestine compared with aorta suggests that the intestine may be a major source of the elevated NO level in this model. In conclusion, NO scavenging with Hb, alone, or in combination with NO synthesis inhibition, appears to be effective in modulating sepsis-mediated vascular hyporeactivity and may reduce complications associated with global NO synthesis inhibition.
The Nucleation of Ice Formation by Silver Iodide (1947)

Silver iodide particles have been found to serve as nuclei for the formation of ice crystals in super-cooled water and in water vapor super-saturated with respect to ice. It is believed that silver iodide serves as a very effective nucleus because it very closely resembles ice in crystal structure. Both dimensions of the unit cell of ice and silver iodide are the same to within approximately one percent. The maximum temperature at which the silver iodide particles serve as nuclei is approximately −4°C for particles one micron in diameter, and −8°C for particles 100 Angstrom units in diameter. A silver iodide smoke generator has been constructed which consumes 1 mg of silver iodide per second and produces 1013 effective nuclei per second.