gebhart/patrepeval huggingface dataset:
Broadband high-resolution multi-species CARS in gas-filled hollow-core photonic crystal fiber (2017)

We report the use of coherent anti-Stokes Raman spectroscopy (CARS) in gas-filled hollow-core photonic crystal fiber (HC-PCF) for trace gas detection. The long optical path-lengths yield a 60 dB increase in the signal level compared with free-space arrangements. This enables a relatively weak supercontinuum (SC) to be used as Stokes seed, along with a ns pump pulse, paving the way for broadband (>4000 cm<sup>-1</sup>) single-shot CARS with an unprecedented resolution of ∼100 MHz. A kagomé-style HC-PCF provides broadband guidance, and, by operating close to the pressure-tunable zero dispersion wavelength, we can ensure simultaneous phase-matching of all gas species. We demonstrate simultaneous measurement of the concentrations of multiple trace gases in a gas sample introduced into the core of the HC-PCF.
Analysis and simulation of anode heating from electron field emission (2003)

This paper considers the effect of anode heating from high-energy electrons produced by field emission. Large fields accelerate emitted electrons as they traverse a vacuum gap toward the anode. Electron energy is transferred to the anode by collisions with the lattice. The nonequilibrium transfer of electron kinetic energy to anode thermal energy is examined. Results demonstrate that the energy distribution of impinging electrons affects the transmission and dissipation of thermal energy. A Monte Carlo technique is used to resolve the thermalization of electrons and accounts for electron beam strength and spatial distribution. The results indicate that local heat fluxes of the order 10 kW/cm/sup 2/ occur at the anode surface and that heating is a strong function of field strength because of the exponential relationship between applied voltage and current. Under practical conditions, temperature increases of 10/spl deg/C are predicted from a single point emission source.
A new approach to a high efficiency inductive store (1991)

A topology has been developed for a highly efficient inductive store suitable for pulsed-power applications. The design features high L/R ratios without having to cryogenically cool the conductors. This allows for high efficiency charging of the inductor from low-impedance DC sources such as batteries or homopolar generators. The inductor design produces very low external flux, which makes it suitable for laboratory applications where magnetic pressures on adjacent conductive structures and EM (electromagnetic) interference noise introduced into control and instrumentation systems is a concern. The inductor may be fabricated in modules for cost-effectiveness and ease of assembly.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
ChemInform Abstract: Synthesis and in vitro Antiproliferative Evaluation of Pyrimido[5,4‐c]quinoline‐4‐(3H)‐one Derivatives. (2012)

Abstract Novel pyrimidoquinolone derivatives (VI),(XI),(XII), and (XIII), substituted at positions 2 and 3, are synthesized by using three synthetic routes and evaluated for their antiproliferative activities against a panel of six human cancer cell lines.
Study on the Effect of Post Weld Heat Treatment Parameters on the Relaxation of Welding Residual Stresses in Electron Beam Welded P91 Steel Plates (2014)

Residual stresses are created by localised heating effects that occur during the welding process. Post weld heat treatment (PWHT) is the most convenient method for stress relief of welds. But PWHT cannot completely eliminate the residual stresses. So, it is essential to determine the influence of PWHT parameters like holding temperature and time on the stress relaxation for optimising the process. The selected material is modified 9Cr-1Mo (Grade 91) steel in the form of plates welded together using a high intensity electron beam. To facilitate the study, a numerical thermo-elastic-plastic model has been developed to simulate the welding of the plates. As P91 steels undergo phase transformations, the corresponding volumetric change and transformation plasticity are taken into consideration during the analysis and welding residual stresses are predicted. PWHT is implemented using Norton creep law and the residual stresses after relaxation are determined. The developed model and the predictions are validated using neutron diffraction measurements on as welded and post weld heat treated plates. A good agreement has been achieved between the measurements and predictions. The validated model has been used to study the effect of variation of heat treatment parameters like holding temperature and time on the relaxation of welding stresses.
Reference materials for calibrating magnetic permeability measuring equipment (1990)

The measurement and comparison of the relative magnetic permeability of weakly magnetic materials at different field strengths by an absolute method and by commercial instrumentation have been undertaken in order to provide reference materials for the calibration of these instruments. The absolute measurement method is described, the main types of commercial instruments are reviewed, and a variety of metals and alloys are examined for possible use as reference standards. The measurements are described, and typical results for permeability measurements using commercial instruments and the absolute method are given. The problems that the users of permeability measuring equipment encounter both in their calibration and in their operation are highlighted.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
RING ENLARGEMENT WITH DIAZOMETHANE IN THE HYDROAROMATIC SERIES<sup>1</sup> (1930)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRING ENLARGEMENT WITH DIAZOMETHANE IN THE HYDROAROMATIC SERIES1Erich Mosettig and Alfred BurgerCite this: J. Am. Chem. Soc. 1930, 52, 8, 3456–3463Publication Date (Print):August 1, 1930Publication History Published online1 May 2002Published inissue 1 August 1930https://pubs.acs.org/doi/10.1021/ja01371a070https://doi.org/10.1021/ja01371a070research-articleACS PublicationsRequest reuse permissionsArticle Views343Altmetric-Citations37LEARN 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
Complete Inhibition of Streptococcus pneumoniae RecA Protein-catalyzed ATP Hydrolysis by Single-stranded DNA-binding Protein (SSB Protein) (2002)

The ATP-dependent three-strand exchange activity of the Streptococcus pneumoniae RecA protein (RecA(Sp)), like that of the Escherichia coli RecA protein (RecA(Ec)), is strongly stimulated by the single-stranded DNA-binding protein (SSB) from either E. coli (SSB(Ec)) or S. pneumoniae (SSB(Sp)). The RecA(Sp) protein differs from the RecA(Ec) protein, however, in that its ssDNA-dependent ATP hydrolysis activity is completely inhibited by SSB(Ec) or SSB(Sp) protein, apparently because these proteins displace RecA(Sp) protein from ssDNA. These results indicate that in contrast to the mechanism that has been established for the RecA(Ec) protein, SSB protein does not stimulate the RecA(Sp) protein-promoted strand exchange reaction by facilitating the formation of a presynaptic complex between the RecA(Sp) protein and the ssDNA substrate. In addition to acting presynaptically, however, it has been proposed that SSB(Ec) protein also stimulates the RecA(Ec) protein strand exchange reaction postsynaptically, by binding to the displaced single strand that is generated when the ssDNA substrate invades the homologous linear dsDNA. In the RecA(Sp) protein-promoted reaction, the stimulatory effect of SSB protein may be due entirely to this postsynaptic mechanism. The competing displacement of RecA(Sp) protein from the ssDNA substrate by SSB protein, however, appears to limit the efficiency of the strand exchange reaction (especially at high SSB protein concentrations or when SSB protein is added to the ssDNA before RecA(Sp) protein) relative to that observed under the same conditions with the RecA(Ec) protein.
A Kinetic Study of the Reaction of Horseradish Peroxidase with Hydrogen Peroxide (1975)

A kinetic study has been carried out over the pH range of 2.63-9.37 for the reaction of horseradish peroxidase with hydrogen peroxide to form compound I of th;e enzyme. Analysis of the results, indicates that there are two kinetic influencing, ionizable groups on the enzyme with pKa values of 3.2 and 3.9. Protonation of these groups results in a decrease in the rate of reaction of the enzyme with H2O2. A previous study of the kinetics of cyanide binding to horseradish peroxidase (Ellis, W.D. & Dunford, H.B.: Biochemistry 7, 2054-2062 (1968)) has been extended to down to pH 2.55, and analysis of these results also indicates the presence of two kinetically important ionizable groups on the enzyme with pKa values of 2.9 and 3.9.
An alternating force magnetometer (1972)

A novel instrument for measuring the magnetic moment of a small specimen of material is formed by applying AC techniques to the traditional force magnetometer (or Faraday magnetometer). The action of the instrument is analysed and an attempt is made to mention all the sources of error and practical difficulty that arise. The new instrument is closely related to the well known vibrating sample magnetometer (although they are at first sight quite different), so the discussion of the new instrument serves also as a discussion of the VSM. A constructed instrument having a sensitivity of 0.2 nA m2 is described.
Nanoporous Polytetrafluoroethylene/Silica Composite Separator as a High‐Performance All‐Vanadium Redox Flow Battery Membrane (2013)

Abstract A novel low‐cost nanoporous polytetrafluoroethylene (PTFE)/silica composite separator has been prepared and evaluated for its use in an all‐vanadium redox flow battery (VRB). The separator consists of silica particles enmeshed in a PTFE fibril matrix. It possesses unique nanoporous structures with an average pore size of 38 nm and a porosity of 48%. These pores function as the ion transport channels during redox flow battery operation. This separator provides excellent electrochemical performance in the mixed‐acid VRB system. The VRB using this separator delivers impressive energy efficiency, rate capability, and temperature tolerance. In additon, the flow cell using the novel separator also demonstrates an exceptional capacity retention capability over extended cycling, thus offering excellent stability for long‐term operation. The characteristics of low cost, excellent electrochemical performance and proven chemical stability afford the PTFE/silica nanoporous separator great potential as a substitute for the Nafion membrane used in VRB applications.
Patterned quantum well semiconductor laser arrays (1989)

Low-threshold arrays of GaAs/AlGaAs patterned quantum well semiconductor lasers were grown by molecular beam epitaxy on periodically corrugated substrates. Uncoated arrays of ∼14 lasers operated with threshold curents of 3.6 mA per laser and emitted up to 375 mW from a single facet under pulsed conditions. The array lasers were not phase locked because of the tight optical confinement in each array channel. A red shift of 300 Å (55 meV) was observed in the emission wavelength of the patterned array compared to that of nonpatterned lasers made on the same substrate. The red shift results from migration effects in the growth on the nonplanar surface, which leads to thicker quantum well active regions at the array channels. This effect illustrates the usefulness of the growth of quantum well heterostructures on nonplanar substrates for lateral band-gap engineering.
Sources of pectin, extraction and its applications in pharmaceutical industry − An overview (2011)

Plant and their products have always been a source of various drugs and excipients used in pharmaceutical formulations. Pectin, a naturally occurring polysaccharide, has in recent years gained increased importance. The benefits of natural pectin are also appreciated by scientists and consumer due to its biodegradability. Pectin is the methylated ester of polygalacturonic acid and it is commercially extracted from citrus peels and apple pomace under mildly acidic conditions. Pectin is divided into two major groups on the basis of their degree of esterification. The association of pectin chains leads to the formation of the three dimensional networks giving gel formation. Since ages pectin is being used in the formulation of various dosage forms wherein it acts as a promising natural polymer for drug delivery. Pectin possesses several requisite characteristics to be used as polymer in drug development and release kinetics. In the present review we have compiled the major sources, extraction process and properties of pectin. The major fields and areas of its applications as a promising polymer have also been discussed. The pectin, by itself or by its gelling properties, is employed in pharmaceutical industry as a carrier for drug delivery to the gastrointestinal tract, such as matrix tablets, gel beads, film-coated dosage form. This review has also discussed the important chemistry and general properties of pectin, and its gel formation mechanism and properties.
New seismic sensors for footstep detection and other military applications (2004)

Performance of seismic security systems relies on the particular application of the characteristics of seismic sensors. Current seismic sensors do not yield best possible results. In addition to identifying the requirements for optimal seismic sensors, we have developed seismic sensors for defense and security applications. We show two different types of seismic sensors: a miniscule, extremely low cost sensor and a bulk sensor. The miniscule, extremely low cost sensor is an electret-based geophone for both seismic and acoustic detection systems. This geophone detects a small size object - i.e. a walking/running/crawling person or a small underwater vehicle-that moves on the surface, underground, and/or in the water. It can also detect large size objects-i.e. heavy vehicles, trucks, tanks-as well as be used in littoral warfare. The electret-based design significantly improves technical characteristics achieving performance uniqueness: expanded frequency response range in the low frequency area, improved sensitivity threshold and accuracy response, and improved sensor's protection from electromagnetic interference. The bulk sensor has an extremely large detection surface, a nanocomposite body in special form casing, and a special electronic circuit. These sensors allow detection of footstep signals in high ambient seismic noise levels. However, installation requires significant installation groundwork effort.
Inhibitors of retroviral DNA polymerase: their implication in the treatment of AIDS. (1985)

Compared to other T-lymphotropic human retroviruses, human T-cell leukemia (lymphotropic) virus I (HTLV-I) and HTLV-II, the acquired immunodeficiency syndrome (AIDS)-associated virus, HTLV-III, is a nontransforming cytopathic virus without immortalizing activity. Thus the virus replication is an important event in the manifestation of this disease, and the interruption of viral replication offers an important strategy for the control of AIDS. For this reason we have purified the reverse transcriptase (RT) from HTLV-III and from HTLV-III infected cells to study the structure-activity relationship of RT inhibitors developed in our laboratory. The cellular DNA polymerases from H9 cells were also purified to study the selectivity of RT inhibitors. Purified HTLV-III RT has several distinguishing features: (a) unlike the HTLV-I enzyme it is highly stable and can be kept for several weeks without any loss of activity; (b) using identical procedures of isolation the HTLV-III enzyme shows a much higher activity than does the enzyme from HTLV-I; (c) the Vmax for HTLV-III RT is by severalfold higher than that for the HTLV-I enzyme in the presence of (rC)n X (dG)12 and (rCm)n X (dG)12, and besides the usual template-primers used for RT assay this enzyme has a relatively high affinity for (rAm)n X (dT)12; and (d) the cationic requirements for the transcription of various template-primers are unusual. The purified enzyme has a molecular weight of 95,000-98,000, as judged by the gel filtration method. The purified HTLV-III RT was inhibited by a partially thiolated polycytidylic acid (5-mercaptopolycytidylic acid); the cellular DNA polymerase beta from H9 cells was not sensitive to 5-mercaptopolycytidylic acid. Germanin (synonym, suramin), an antiprotozoan drug, also inhibits HTLV-III RT activity, but the DNA polymerase alpha activity was also sensitive to Germanin. The nonspecific effect of Germanin is probably due to the high content of sulfonic acid residues. This paper describes new approaches for designing specific inhibitors of retroviral reverse transcriptases which may be useful in developing a potential drug against AIDS.
Postentry Restriction to Human Immunodeficiency Virus-Based Vector Transduction in Human Monocytes (2001)

Cells of the monocyte lineage can be infected with human immunodeficiency virus type 1 (HIV-1) both during clinical infection and in vitro. The ability of HIV-1-based vectors to transduce human monocytes, monocyte-derived macrophages, and dendritic cells (DCs) was therefore examined, in order to develop an efficient protocol for antigen gene delivery to human antigen-presenting cells. Freshly isolated monocytes were refractory to HIV-1-based vector transduction but became transducible after in vitro differentiation to mature macrophages. This maturation-dependent transduction was independent of the HIV-1 accessory proteins Vif, Vpr, Vpu, and Nef in the packaging cells and of the central polypurine tract in the vector, and it was also observed with a vesicular stomatitis virus-pseudotyped HIV-1 provirus, defective only in envelope and Nef. The level and extent of reverse transcription of the HIV-1-based vector was similar after infection of immature monocytes and of mature macrophages. However, 2LTR vector circles could not be detected in monocytes, suggesting a block to vector nuclear entry in these cells. Transduction of freshly isolated monocytes exposed to HIV-1-based vector could be rescued by subsequent differentiation into DCs. This rescue was induced by fetal calf serum in the DC culture medium, which promoted vector nuclear entry.
Plane Strain Indentation of Snow at the Microscale (2008)

Indentation tests are commonly used to characterize terrain properties in tire-terrain interaction. By way of motivation, in order to understand and quantify the sources of uncertainty in tire-snow interaction, we present a new direction of research studying the indentation behavior of snow at the microscale. The mechanical behavior of snow is known to be influenced significantly by its microstructure which can evolve due to environmental conditions. The traction and compaction of snow due to interfacial friction and contact exerted by various parts of the tire thus should also be dependent on snow’s microstructure. Due to the geometric scales of parts of the tire, from sipes to tread blocks, tire-snow interaction is inherently a multi-scale problem ranging from microscale to macroscale. This paper addresses the microscale behavior of medium-density snow (density 387 kg / m3) whose microstructure is obtained via 3-D X-Ray Microtomography (XMT). A physically based, history and rate dependent viscoplastic model for polycrystalline ice was incorporated into a meshfree Material Point Method simulation code using an implicit algorithm on a parallel computer for the indentation of a punch on snow under the plane strain condition at a nominal strain rate of 0.0014 Sec−1. Load/pressure vs. sinkage/strain relationship was obtained and compared with macroscopic pressure-sinkage relationship. Micromechanical behavior of the indentation test was also presented and discussed.
A simulation model of alluvial stratigraphy (1979)

ABSTRACT The quantitative model presented simulates the development of a two‐dimensional alluvial sedimentary succession beneath a floodplain traversed by a single major river. Several inter‐related effects which influence the distribution of channel‐belt sand and gravel bodies within overbank fines are accounted for. These are (a) laterally variable aggradation, (b) compaction of fine sediment, (c) tectonic movement at floodplain margins, and (d) channel avulsion. Selected experiments with the model show how the interconnectedness and areal density of channel‐belt deposits decrease with increasing floodplain width/channel‐belt size, mean avulsion period, and channel‐belt aggradation rate. Separation of stream patterns based on interconnectedness and channel deposit density is difficult. Tectonic movements do not have a significant influence upon the successions unless a preferred direction of tilting is maintained (half‐graben). Then channel‐belt deposits showing offlap tendencies tend to cluster adjacent to the active floodplain margin, leaving dominantly fine‐grained alluvium to accumulate on the inactive side. Individual channel‐belt deposits thicken during aggradation, although a self‐regulating limit to such thickening is likely to operate. ‘Multistorey’features resulting from aggradation may be difficult to tell apart from those arising through superposition of distinct channel‐belt deposits of avulsive origin.
Accessibility of selenomethionine proteins by total chemical synthesis: structural studies of human herpesvirus‐8 MIP‐II (1998)

The determination of high resolution three-dimensional structures by X-ray crystallography or nuclear magnetic resonance (NMR) is a time-consuming process. Here we describe an approach to circumvent the cloning and expression of a recombinant protein as well as screening for heavy atom derivatives. The selenomethionine-modified chemokine macrophage inflammatory protein-II (MIP-II) from human herpesvirus-8 has been produced by total chemical synthesis, crystallized, and characterized by NMR. The protein has a secondary structure typical of other chemokines and forms a monomer in solution. These results indicate that total chemical synthesis can be used to accelerate the determination of three-dimensional structures of new proteins identified in genome programs.