gebhart/patrepeval huggingface dataset:
Synthesis of Substituted Pyrazines. I. 2-Substituted 3-Methylpyrazines<sup>1,2</sup> (1961)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of Substituted Pyrazines. I. 2-Substituted 3-Methylpyrazines1,2JOHN D. BEHUN, PETER T. KAN, PATRICIA A. GIBSON, CARL T. LENK, and EDWARD J. FUJIWARACite this: J. Org. Chem. 1961, 26, 12, 4981–4987Publication Date (Print):December 1, 1961Publication History Published online1 May 2002Published inissue 1 December 1961https://pubs.acs.org/doi/10.1021/jo01070a048https://doi.org/10.1021/jo01070a048research-articleACS PublicationsRequest reuse permissionsArticle Views97Altmetric-Citations3LEARN 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
Geometric separator theorems and applications (2002)

We find a large number of "geometric separator theorems" such as: I: Given N disjoint isooriented squares in the plane, there exists a rectangle with /spl les/2N/3 squares inside, /spl les/2N/3 squares outside, and /spl les/(4+0(1))/spl radic/N partly in & out. II: There exists a rectangle that is crossed by the minimal spanning tree of N sites in the plane at /spl les/(4/spl middot/3/sup 1/4/+0(1))/spl radic/N points, having /spl les/2N/3 sites inside and outside. These theorems yield a large number of applications, such as subexponential algorithms for traveling salesman tour and rectilinear Steiner minimal tree in R/sup d/, new point location algorithms, and new upper and lower bound proofs for "planar separator theorems".
New Bridgeless DCM Sepic and Cuk PFC Rectifiers With Low Conduction and Switching Losses (2011)

New bridgeless single-phase ac-dc power factor correction (PFC) rectifiers based on Sepic and Cuk topologies are proposed. The absence of an input diode bridge and the presence of only two semiconductor switches in the current flowing path during each switching cycle result in less conduction losses and improved thermal management compared to the conventional Sepic and Cuk PFC converters. The proposed topologies are designed to work in discontinuous conduction mode (DCM) to achieve almost unity power factor in a simple and effective manner. The DCM operation gives additional advantages such as zero-current turn-on in the power switches, zero-current turn-off in the output diode and reduces the complexity of the control circuitry. The proposed rectifiers are theoretically investigated. Performance comparisons between the proposed and conventional Sepic PFC rectifiers are performed. Simulation and experimental results are provided for a design example of a 65-W/48-V at 100- V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> line voltage to evaluate the performance of the proposed PFC rectifier.
Oxidation of Sputtered Thin Films of Molybdenum Alloys at Ambient Conditions (2009)

*, C. Mitterer*, G. Mori**, J. Winkler***, N. Reinfried*** and W. Knabl*** * Department of Physical Metallurgy and Materials Testing, Montanuniversitat, Leoben, Austria ** Department of General, Analytical and Physical Chemistry, Montanuniversitat, Leoben, Austria *** PLANSEE Metall GmbH, Reutte, Austria Room temperature oxidation of Mo in the presence of humidity may deteriorate its properties in thin film applications like thin film transistor liquid crystal displays or photovoltaic cells. To improve their oxidation resistance, Mo films of 200 nm thickness, alloyed with the elements Ti, Cr, Ni, Nb, Ta, or W, respectively, have been grown by magnetron co-sputtering from Mo mosaic targets with the respective alloying element inserts. All coatings show single-phase solid solutions. The respective alloying content is determined by the number of target inserts, their respective sputter yield and the scattering probability during transport from the target to the substrate, and could be confirmed by SRIM calculations. Electrical resistivity values are comparable to those of unalloyed Mo. Corrosion properties have been determined in 85 % humidity at 85°C by use of exposure tests in a climatic chamber. Potentiodynamic and electrochemical impedance spectroscopy were additionally done in 0.9 % NaCl aqueous solution at room temperature. Cr was identified as the alloying element resulting in the highest corrosion resistance due to formation of a passive layer.
Pore scale modeling of rock properties and comparison to laboratory measurements (2009)

The microstructure of a porous medium and the physical characteristics of the solid and the fluids that occupy the pore space determine the macroscopic transport properties of the medium. The computation of macroscopic properties from the rock microtomography is becoming an increasingly studied topic (Alder et al., 1990; Arns, 2001; Pal et al., 2002; Kameda et al., 2006; Toumelin et al., 2008). The purpose of this paper is to test numerical calculations of the geometrical and transport properties (electrical conductivity, permeability, specific surface area and surface conductivity) of porous, permeable rocks, given the 3D digital microtomography images. In this paper, we focus on the 3D X‐ray microtomograhpy of a 23.6% porosity Berea Sandstone 500 (BS500) core sample with 2.8 micron resolution. Numerical calculations of electrical conductivity (with and without presence of surface conductivity), permeability and surface area on the image will be compared to the laboratory measurements on core samples. The impact of image resolution on our calculation is also analyzed.
The Role of Biotechnology in the Production of the Anticancer Compound Podophyllotox (2009)

Podophyllotoxin is a plant-derived compound found in Podophyllum sp. that is used to produce semi-synthetic anticancer pharmaceuticals such as etoposide, teniposide, and etoposide phosphate. This chapter describes the role of biotechnology to produce podophyllotoxin and our attempts to domesticate Podophyllum peltatum L., also known as the American mayapple. The domestication research on mayapple included surveys of the natural population, identification of high yielding genotypes, propagation, cultivation, sustainable harvest procedures and the development of protocols for in vitro germplasm bank.
Syntheses of isoquinolines by condensation of dopamine with carbonyl compounds. (1975)

In 1911, Pictet and Spengler1) allowed -phenethyl amine and aldehydes to react in hydrochloric acid, synthesized 1, 2, 3, 4,-tetrahydroisoquinoline derivatives and demonstrated synthesis of isoquinoline alkaloid organic chemically. This reaction is called Pictet Spengler reaction. Decker et al.2) suggested that the reaction goes through Schiff base as the intermediate.
Design and simulation of an interferometric Doppler radar altimeter (2003)

Interferometry techniques can be effectively applied to nadir looking radar altimeters to allow elevation measurement capability over non-stationary surfaces, such as ice, terrain and coastal lines. The main design criteria of such an instrument are described in the paper and the elevation measurement performance over real-topography scenes are assessed through numerical simulation.
Studies on the Specificity and Site of Action of α-Cyclopropyl-α-[<i>p</i>-methoxyphenyl]-5-pyrimidine Methyl Alcohol (Ancymidol), a Plant Growth Regulator (1978)

alpha-Cyclopropyl-alpha-[p-methoxyphenyl]-5-pyrimidine methyl alcohol (ancymidol) is an inhibitor of ent-kaur-16-ene oxidation in microsomal preparations from the liquid endosperm of immature Marah macrocarpus seeds. The K(i) for this inhibitor is about 2 x 10(-9)m. Ancymidol also blocks ent-kaur-16-en-19-ol and ent-kaur-16-en-19-al oxidation by the same preparations with a similar efficiency, but does not significantly inhibit ent-kaur-16-en-19-oic acid oxidation. Ancymidol appears to be specific for this series of oxidations in higher plant tissues. It does not inhibit the oxidation of kaurene nor kaurenoic acid in rat liver microsomes and has no significant effect on the oxidation of cinnamic acid in microsomal preparations from Sorghum bicolor seedlings. Ancymidol also does not inhibit kaurene oxidation in vitro nor in vivo in cultures of the fungus Fusarium moniliforme. The presence of ancymidol did not significantly alter the activities of NADPH-cytochrome c reductase, NADH-cytochrome c reductase, or NADH-cytochrome b(5) reductase. The addition of ancymidol to suspensions of oxidized M. macrocarpus endosperm led to a difference spectrum with an absorption maximum at 427 nm and a minimum at 410 nm.
Use administrative databases with caution (2009)

[Two of the authors respond:] We were aware that the primary discharge diagnosis of Clostridium difficile infection may not have been the admitting diagnosis, but we estimated the magnitude of such miscoding in our study to be low (< 5%) for the following reasons.[1][1] We agree with Hubert and
Quick tour of fluorescence correlation spectroscopy from its inception (2004)

Fluorescence correlation spectroscopy (FCS) was originally developed in the early 1970s as a way to measure the kinetics of chemical reactions under zero perturbation conditions. At its inception, the measurement was difficult due to experimental limitations and was primarily used during the 1970s and 1980s to characterize diffusion. More recently, as a result of technological advances, FCS measurements have become easier and more versatile. In addition to measurements of diffusion both in solution and in cells, FCS is now also used to measure not only chemical reaction kinetics but also extents of molecular aggregation, the dynamics of photophysical processes, conformational fluctuations, molecular interactions in solution and in cells, and has even found application as a pharmaceutical screening method. From its inception to the present, the contributions of Webb and his coworkers have had a central and defining role in the development and applications of FCS.
Vascular development in chick embryos: a possible role for adenosine (1989)

We studied the possible role of adenosine in the development of the vasculature using 217 chick embryos. Adenosine (2-32 mumol/day), inosine (16 mumol/day), dipyridamole (0.04-0.4 mumol/day), or aminophylline (400 and 800 micrograms/day) were administered twice each day into the air space on days 11-14. Control embryos received Ringer solution. Whole body vascularity was estimated on day 15 as the whole body structural vascular resistance (SVR), i.e., the hydraulic resistance of the maximally dilated vasculature. Adenosine decreased the SVR in a dose-related manner at the lower dosage amounts but caused a maximum decrease in SVR at the higher dosage amounts averaging 30% below the Ringer control values. Equimolar amounts of adenosine and inosine decreased the SVR by the same extent. Dipyridamole, which potentiates the biological effects of endogenous adenosine, also decreased the SVR in a dose-related manner to values averaging approximately 30% below control. When the effects of endogenous adenosine were blocked by aminophylline, the SVR increased in a dose-related manner to approximately 100% above control at the highest dosage amount. These results suggest that adenosine could have a physiological role in growth regulation of the vascular system in the chick embryo.
Catalysis of nanotube plasticity under tensile strain (2002)

We have performed ab initio simulations to investigate the effect of carbon adatoms on the plastic deformation of carbon nanotubes. Under applied stress, the system spontaneously undergoes a Stone-Wales transformation catalyzed by the exchange of the adatom with a substrate atom. The unraveled mechanism reduces the barrier by a factor 3 to 5 and is the same as the one recently proposed by Ewels et al. [Chem. Phys. Lett. 351, 178 (2002)] for ${\mathrm{C}}_{60}.$ The activation energies for such a transformation in graphene and nanotube systems under various stresses are obtained within an ab initio nudged elastic band approach. The catalytic action is enhanced when the carbon adatom is replaced by boron.
Three Dimensional Culture of Human Renal Cell Carcinoma Organoids (2015)

Renal cell carcinomas arise from the nephron but are heterogeneous in disease biology, clinical behavior, prognosis, and response to systemic therapy. Development of patient-specific in vitro models that efficiently and faithfully reproduce the in vivo phenotype may provide a means to develop personalized therapies for this diverse carcinoma. Studies to maintain and model tumor phenotypes in vitro were conducted with emerging three-dimensional culture techniques and natural scaffolding materials. Human renal cell carcinomas were individually characterized by histology, immunohistochemistry, and quantitative PCR to establish the characteristics of each tumor. Isolated cells were cultured on renal extracellular matrix and compared to a novel polysaccharide scaffold to assess cell-scaffold interactions, development of organoids, and maintenance of gene expression signatures over time in culture. Renal cell carcinomas cultured on renal extracellular matrix repopulated tubules or vessel lumens in renal pyramids and medullary rays, but cells were not observed in glomeruli or outer cortical regions of the scaffold. In the polysaccharide scaffold, renal cell carcinomas formed aggregates that were loosely attached to the scaffold or free-floating within the matrix. Molecular analysis of cell-scaffold constructs including immunohistochemistry and quantitative PCR demonstrated that individual tumor phenotypes could be sustained for up to 21 days in culture on both scaffolds, and in comparison to outcomes in two-dimensional monolayer cultures. The use of three-dimensional scaffolds to engineer a personalized in vitro renal cell carcinoma model provides opportunities to advance understanding of this disease.
A Practical Synthesis of <i>threo</i>-3-Amino-2-hydroxycarboxylic Acids (1992)

Abstract An expeditious synthesis of (2R,3S)-3-amino-4-cyclohexyl-2-hydroxybutyric acid (2) and (2S,3R)-3-amino-2-hydroxy-4-phenylbutyric acid (4), the key components of the renin inhibitor (1) and bestatin (3), respectively, have been accomplished by featuring highly diastereoselective formation of cyanohydrin acetates from α-alkoxycarbonylamino aldehydes under phase-transfer conditions.
Coherent pulse stacking amplification using low-finesse Gires-Tournois interferometers (2015)

We demonstrate a new technique of coherent pulse stacking (CPS) amplification to overcome limits on achievable pulse energies from optical amplifiers. CPS uses reflecting resonators without active cavity-dumpers to transform a sequence of phase- and amplitude-modulated optical pulses into a single output pulse. Experimental validation with a single reflecting resonator demonstrates a near-theoretical stacked peak-power enhancement factor of ~2.5 with 92% and 97.4% efficiency for amplified nanosecond and femtosecond pulses. We also show theoretically that large numbers of equal-amplitude pulses can be stacked using sequences of multiple reflecting resonators, thus providing a new path for generating very high-energy pulses from ultrashort pulse fiber amplifier systems.
Dynamic Channel Adaptation for AC Synchronized Powerline Channel (2008)

technology allows the usage of electrical power supply networks for communications purposes, such as audio/video streaming and broadband internet access. The powerline has an inherent characteristic that is the cyclic variation of channel and noise with the phase of the AC line cycle. To achieve either high throughput or high robustness, we apply dynamic channel adaptation scheme that exploits the cyclic variation of powerline characteristics. In this paper, we introduce an expedient, dynamic channel adaptation which is robust against the short-time variation of the AC synchronized powerline channel and noise. We analyze the performance enhancement for the measured powerline channel and noise when the proposed adaptation scheme is applied to the Korean standard on high speed powerline communications. Analysis of the simulation result has shown that an average of 30 % improvement in the throughput can be achieved by using AC line based adaptation.
Synchrotron white-beam X-ray topography of ribonuclease S crystals (2002)

With careful experimental design, indexed synchrotron white-beam X-ray topographs of ribonuclease S crystals at ambient temperature could be recorded with a definition and contrast comparable to that of monochromatic beam topographs of other proteins reported in the literature. By excluding wavelengths longer than 1 A from the white beam with a filter, a radiation dose equivalent to that required to record about 18 topographs could be tolerated without appreciable radiation damage to the samples. Bragg angles of 0.5 degrees or less were required to select low-index harmonically pure reflections with high intensities and extinction lengths only several times the sample's thickness. The resulting X-ray topographs in some cases showed topographic detail and in others showed the even featureless background that has been considered characteristic of a protein crystal of low mosaicity. The ribonuclease S crystals were well ordered single crystals of a quality comparable to other protein crystals that have been studied by X-ray topography.
Sulfonated Polyimide Ionomers: A Structural Study (2003)

The morphology of a series of sulfonated polyimide ionomers was investigated by small-angle X-ray and neutron scattering (SAXS and SANS) as a function of different parameters such as the ionic content, the ionic groups distribution, and the flexibility of the polymer chain. Both SAXS and SANS data exhibit the presence of an ionomer peak, indicating the presence of large ionic domains for most of the polymers. The dimension and the distribution of the ionic aggregates depend significantly on the ionic groups distribution along the polymer, and no structural evolution at nanoscopic scale accompanies the swelling process. It was found that the Dreyfus local order model where the structure of the ionic domains is locally ordered with a first four neighbors followed by a gaslike structure distribution, reproduces well our experimental data. On the other hand, the ionomer peak is not observed for very rigid polymers despite the presence of large ionic domains.
Patients with psoriasis prefer solution and foam vehicles: a quantitative assessment of vehicle preference. (2002)

Psoriasis patients' acceptance of the vehicles used in topical therapy contributes to adherence to treatment plans and outcomes, but patient preferences for different vehicles have not been assessed. The purpose of this study was to develop a quantitative measure of patient preferences for different vehicles and to assess these preferences. Focus group sessions were conducted of patients with psoriasis to determine patient perceptions of the advantages and disadvantages of different topical psoriasis therapies. This information was used to derive a vehicle preference measure to assess different topical therapies. Twenty patients with psoriasis sampled different topical psoriasis medications, assessed the effects of the vehicles on quality of life (QOL), and completed the preference measure for each vehicle. The focus group sessions resulted in the development of a 7-item preference measure. The validity of the vehicle preference measure was demonstrated by good correlation with patient expectations of effects on QOL and by test-retest reliability. The foam and solution vehicles were preferred over the cream, gel, and ointment vehicles (P < .01). There was no significant difference between preferences for daytime and nighttime application of vehicles. Although validated measures of adherence to topical therapy are not yet available, the results of this study suggest that the characteristics of solution and foam may favor improved adherence to topical therapy.
The pathophysiology of ovarian hyperstimulation syndrome--views and ideas (1997)

Ovarian hyperstimulation syndrome (OHSS) is a serious complication affecting ovulation induction. Its most severe manifestation takes the form of massive ovarian enlargement and multiple cysts, haemoconcentration and third-space accumulation of fluid. The full-blown clinical syndrome may be complicated by renal failure and oliguria, hypovolaemic shock, thromboembolic episodes, adult respiratory distress syndrome (ARDS), and death. Although the pathophysiology of this syndrome has not been completely elucidated, it seems likely that the increased capillary permeability triggered by the release of vasoactive substance secreted by the ovaries under human chorionic gonadotrophin (HCG) stimulation plays a key role in this syndrome. Several factors such as histamine, serotonin, prostaglandins, prolactin, and a variety of other substances have been implicated in this process in the past. At present, factors belonging to the renin-angiotensin system, cytokines including the interleukins, tumour necrosis factor alpha, endothelin-1 and vascular endothelial growth factor (VEGF) are thought to be involved in triggering increased vascular permeability after ovulation induction treatment. This manuscript summarizes the current knowledge of the pathophysiology of ovarian hyperstimulation syndrome with emphasis on the correlation of the various factors with the clinical phenomena of this iatrogenic syndrome.
Lower Limb-Length Discrepancy (1991)

Two retrospective epidemiologic studies have examined the incidence and prevalence of significant lower limb-length discrepancy and the number of surgical corrections by lengthening in 1987 in France. The incidence of apparatus prescriptions for asymmetry correction filled was 2.16 per 100,000 population. The prevalence of people using a corrective apparatus was one per 1000 population. The male-to-female ratio was 1.95:1. Because of biases in the study population, the actual incidence and prevalence of significant limb-length discrepancies is likely to be considerably higher. A questionnaire administered to surgeons of the French Orthopedic Society revealed that the majority of surgical lengthenings were performed by large orthopedic teams. In the 418 procedures reported, the tibia was lengthened more often than the femur (ratio 1.1:1). Gradual distraction techniques were used in 89.4% of cases, with the Ilizarov apparatus used in 57.4%, the Wagner apparatus in 20.6%, and the Orthofix fixator in 11.2%. Immediate distraction techniques were used in 7.9% of cases, 85% of which were done on the femur. Average total lengthening was 51 mm for tibia and femur. Average lengthening was greater for methods of gradual distraction (53.5 mm) than for immediate distraction (31.4 mm).