gebhart/patrepeval huggingface dataset:
Conformationally Biased Selective Alkylation of <i>trans</i>‐Cyclohexane‐1,2‐bis(sulfonamide) Assisted by Solvent‐Tuned Protecting Groups: Applications to the Synthesis of a Large Optically Active Polyazamacrocycle (2006)

Abstract The selective alkylation of ( R , R )‐cyclohexane‐1,2‐bis(sulfonamide) with trityl bromoalkyl ethers has been studied in detail. The major formation of either mono‐ or dialkylated compounds clearly depends on the right combination of protecting groups and the reaction solvent. An exhaustive study suggests that this effect can be reasonably explained by the conformational preferences of the monoalkylated compounds, which also depend on the reaction medium, solvophobic effects and weak intramolecular interactions. Structural analysis by NOE measurements showed the presence of folded conformations in solution for all the tested examples. Monte Carlo conformational searches supported this proposal, showing a very good correlation between the fraction of folded species and the selectivity towards monoalkylation. Finally, tuning of the reaction conditions, leading to either extended or folded conformations of the monoalkylated synthetic intermediates, was exploited for the efficient synthesis of a large optically active polyazamacrocycle. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Cytotoxic activity of marine algae against cancerous cells (2013)

This paper presents an investigation on the cytotoxic activity in human tumor cell from dichloromethane, chloroform, methanol, ethanol, water extracts, and hexane and chloroform fractions from green, brown and red algae collected at Riacho Doce Beach, north coast of Alagoas, Brazil, against the cancer cells K562 (chronic myelocytic leukemia), HEp-2 (laryngeal epidermoid carcinoma) and NCI-H292 (human lung mucoepidermoid carcinoma) through the MTT colorimetric method. The dichloromethane extract and chloroform fraction of Hypnea musciformis showed the best cytotoxic activity against K562 (3.8±0.2 μg.mL-1 and 6.4±0.4 μg.mL-1, respectively). Dichloromethane extracts of Dictyota dichotoma (16.3±0.3 μg.mL-1) and the chloroform fraction of H. musciformis (6.0±0.03 μg.mL-1) and chloroform fraction of P. gymnospora (8.2±0.4) were more active against HEp-2 as well as ethanol extracts of P. gymnospora (15.9±2.8 μg.mL-1) and chloroform fraction of H. musciformis (15.0±1.3 μg.mL-1) against the cell NCI-H292. The constituents with higher anticancer action are present in the extracts of dichloromethane and chloroform and in the chloroform fraction of H. musciformis, Digenea simplex, P. gymnospora, and D.dichotoma. In the case of the seaweed S. vulgare, the anticancer constituents are present in the aqueous extract.
Positions open to graduate students majoring in chemistry, in various colleges and universities (1927)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPositions open to graduate students majoring in chemistry, in various colleges and universitiesWilliam McPherson Cite this: J. Chem. Educ. 1927, 4, 1, 96Publication Date (Print):January 1, 1927Publication History Received3 August 2009Published online1 January 1927Published inissue 1 January 1927https://doi.org/10.1021/ed004p96Request reuse permissions Article Views16Altmetric-Citations-LEARN 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 InReddit PDF (1 MB) Get e-Alertsclose Get e-Alerts
Global patterns of terrestrial biological nitrogen (N<sub>2</sub>) fixation in natural ecosystems (1999)

Human activities have clearly caused dramatic alterations of the terrestrial nitrogen cycle, and analyses of the extent and effects of such changes are now common in the scientific literature. However, any attempt to evaluate N cycling processes within ecosystems, as well as anthropogenic influences on the N cycle, requires an understanding of the magnitude of inputs via biological nitrogen fixation (BNF). Although there have been many studies addressing the microbiology, physiology, and magnitude of N fixation at local scales, there are very few estimates of BNF over large scales. We utilized >100 preexisting published estimates of BNF to generate biome‐ and global‐level estimates of biological N fixation. We also used net primary productivity (NPP) and evapotranspiration (ET) estimates from the Century terrestrial ecosystem model to examine global relationships between these variables and BNF as well as to compare observed and Century‐modeled BNF. Our data‐based estimates showed a strong positive relationship between ecosystem ET and BNF, and our analyses suggest that while the model's simple relationships for BNF predict broad scale patterns, they do not capture much of the variability or magnitude of published rates. Patterns of BNF were also similar to patterns of ecosystem NPP. Our “best estimate” of potential nitrogen fixation by natural ecosystems is ∼195 Tg N yr −1 , with a range of 100–290 Tg N yr −1 . Although these estimates do not account for the decrease in natural N fixation due to cultivation, this would not dramatically alter our estimate, as the greatest reductions in area have occurred in systems characterized by relatively low rates of N fixation (e.g., grasslands). Although our estimate of BNF in natural ecosystems is similar to previously published estimates of terrestrial BNF, we believe that this study provides a more documented, constrained estimate of this important flux.
Some distance properties of tailbiting codes (2002)

The active tailbiting segment distance for convolutional codes is introduced. Together with the earlier defined active burst distance, it describes the error correcting capability of a tailbiting code encoded by a convolutional encoder. Lower bounds on the new active distance as well as an upper bound on the ratio between tailbiting length and memory of the encoder such that its minimum distance d/sub min/ equals the free distance d/sub free/ of the corresponding convolutional code are presented.
Study On Microbial Pretreatment For Enhancing Enzymatic Hydrolysis Of Corncob (2014)

The complex structure of lignocellulose leads to great<br> difficulties in converting it to fermentable sugars for the ethanol<br> production. The major hydrolysis impediments are the crystallinity of<br> cellulose and the lignin content. To improve the efficiency of<br> enzymatic hydrolysis, microbial pretreatment of corncob was<br> investigated using two bacterial strains of Bacillus subtilis A 002 and<br> Cellulomonas sp. TISTR 784 (expected to break open the crystalline<br> part of cellulose) and lignin-degrading fungus, Phanerochaete<br> sordida SK7 (expected to remove lignin from lignocellulose). The<br> microbial pretreatment was carried out with each strain under its<br> optimum conditions. The pretreated corncob samples were further<br> hydrolyzed to produce reducing glucose with low amounts of<br> commercial cellulase (25 U·g-1 corncob) from Aspergillus niger. The<br> corncob samples were determined for composition change by X-ray<br> diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),<br> and scanning electron microscope (SEM). According to the results,<br> the microbial pretreatment with fungus, P. sordida SK7 was the most<br> effective for enhancing enzymatic hydrolysis, approximately, 40%<br> improvement.
A Comparison of Approaches for Tracking in Naval Environments (2010)

Abstract : The authors have investigated image analysis methods for tracking moving objects in marine environments. They focused on information-theoretic approaches that compare image regions of interest with the statistical models of the objects to be tracked. They evaluated the tracking performance of mean-shift and block-matching algorithms on videos of waterways. It is challenging to track naval vessels in these videos due to glare from the water surface, up and down movements of vessels, and occlusions. They found that the performance of the mean-shift tracking approach was superior to the performance of the block-matching approach in videos with low contrast between the naval vessels to be tracked and the surrounding water surface, and where the scale and orientation of the vessels changed.
Communication architecture and performance analysis of protocols for RTT infrastructure networks and vehicle-roadside communications (2002)

A proposal for a communication architecture for road transport telematics (RTT) infrastructure networks is presented. First, the technical approach which has been set up to cope with the relevant subjects is introduced. Then, the communication requirements of RTT applications are considered. Following that, the protocol profile is defined which includes a protocol stack for the vehicle-roadside communications via beacons (DSRC). Thereupon, the protocol evaluation and the co-operation between the beacons and the fixed network ape discussed. Finally, the performance analysis of medium access control (MAC) protocols for the DSRC and for the fixed network are addressed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Attenuation of food allergy symptoms following treatment with human milk oligosaccharides in a mouse model (2015)

Our results suggest that 2'-fucosyllactose and 6'-sialyllactose reduce the symptoms of food allergy through induction of IL-10(+) T regulatory cells and indirect stabilization of mast cells. Thus, human milk oligosaccharides may have therapeutic potential in allergic disease.
EXCESSIVE SYMPATHETIC ACTIVATION IN HEART FAILURE ASSOCIATED WITH ANEMIA: PP.32.260 (2010)

The role of anemia in determining sympathetic overactivity in chronic heart failure (CHF) patients is unknown. We tested the hypothesis that in CHF patients, anemia could lead to increased sympathetic activity through tonic activation of excitatory chemoreceptor afferents. We conducted a double-blind, randomized, vehicle-controlled study to examine the effect of chemoreflex deactivation on muscle sympathetic nerve activity in CHF patients with and without anemia. We compared the effect of breathing 100% oxygen for 15 min in 18 stable CHF patients with anemia and 18 control CHF patients matched for age, sex, blood pressure and BMI. Baseline muscle sympathetic nerve activity was significantly elevated in CHF patients with anemia compared with patients with CHF alone (56.0 ± 3.2 versus 45.5 ± 3.1 bursts/min; P < 0.0237). Administration of 100% oxygen led to a significant decrease in muscle sympathetic nerve activity in CHF patients with anemia (from 56.0 ± 3.4 to 50.9 ± 3.2 bursts/min; P < 0.0019). In contrast, neither room air nor 100% oxygen changed muscle sympathetic nerve activity or hemodynamics in patients with CHF alone. We report for the first time direct evidence of increased sympathetic nerve traffic in patients with CHF-related anemia. Sympathetic hyperactivity in patients with CHF and anemia is partially chemoreflex mediated and could explain how anemia contributes to the progression of CHF and increases morbidity and mortality in these patients.
Inhibition of Substance P-Induced Cytokine Synthesis by St. John's Wort Extracts (2001)

We tested the hypothesis that extracts from St. John's wort interfere with protein synthesis induced by substance P (SP), a neuropeptide which has been implicated in the etiopathology of depression and anxiety. Using human astrocytoma cells, which express functional neurokinin (NK)-1-receptors, we investigated whether extracts from St. John's wort are able to inhibit SP-induced synthesis of the cytokine interleukin-6 (IL-6). We found a potent and dose-dependent inhibition of SP-induced IL-6 synthesis by various extracts from St. John's wort. These results do not only give further evidence of the anti-inflammatory effects of St. John's wort, but also lend support to the hypothesis that the antidepressant effect of St. John's wort is, at least in part, a result of its inhibitory effects on SP-induced protein synthesis.
La répartition des dépenses de la population française en fonction de ses besoins (1953)

Bénard Jean. La répartition des dépenses de la population française en fonction de ses besoins. In: Population, 8ᵉ année, n°2, 1953. pp. 211-238.
The Colors of Platinum, Palladium, and Rhodium in Simple Glasses (1956)

A study was made of the colors produced by platinum, palladium, and rhodium when they were introduced as their chlorides in alkali silicate, borate, and phosphate glasses. Yellow, pinkish‐yellow, orange, and brown colors in addition to aventurines and grays were observed in the various glasses. Platinum exhibits an interesting behavior in phosphate glasses. Small additions of platinum chloride produce gray colors, whereas larger amounts produce yellow and orange colors. Nucleation by platinum crystals leading to devitrification was observed in some phosphate glasses.
<title>Wigner function and ambiguity function for nonparaxial wavefields</title> (2001)

The connection between the Wigner function and the generalized OTF, and between the ambiguity function and the generalized OTF is investigated for non-paraxial scalar wavefields. The treatment is based on two-dimensional (2-D) wavefields for simplicity, but can be extended to the three- dimensional case.
Differential Binding of Heterogeneous Nuclear Ribonucleoproteins to mRNA Precursors prior to Spliceosome Assembly In Vitro (1992)

We have investigated the composition of the earliest detectable complex (H) assembled on pre-mRNA during the in vitro splicing reaction. We show that most of the proteins in this complex correspond to heterogeneous nuclear ribonucleoproteins (hnRNP), a set of abundant RNA-binding proteins that bind nascent RNA polymerase II transcripts in vivo. Thus, these studies establish a direct parallel between the initial events of RNA processing in vitro and in vivo. In contrast to previous studies, in which total hnRNP particles were isolated from mammalian nuclei, we determined the hnRNP composition of complexes assembled on individual RNAs of defined sequence. We found that a unique combination of hnRNP proteins is associated with each RNA. Thus, our data provide direct evidence for transcript-dependent assembly of pre-mRNA in hnRNP complexes. The observation that pre-mRNA is differentially bound by hnRNP proteins prior to spliceosome assembly suggests the possibility that RNA packaging could play a central role in the mechanism of splice site selection, as well as other posttranscriptional events.
Surface and Interfacial Organometallic Chemistry and Catalysis. Topics in Organometallic Chemistry, 16 Edited by Christophe Copéret (Laboratoire de Chimie Organometallique de Surface, Villeurbanne, France) and Bruno Chaudret (Laboratoire de Chimie de Coordination du CNRS, Toulouse, France). Springer:  Berlin, Heidelberg, New York. 2005. x + 291 pp. $259.00. ISBN 3-540-26496-5. (2007)

ADVERTISEMENT RETURN TO ISSUEPREVBook ReviewNEXTSurface and Interfacial Organometallic Chemistry and Catalysis. Topics in Organometallic Chemistry, 16 Edited by Christophe Copéret (Laboratoire de Chimie Organometallique de Surface, Villeurbanne, France) and Bruno Chaudret (Laboratoire de Chimie de Coordination du CNRS, Toulouse, France). Springer: Berlin, Heidelberg, New York. 2005. x + 291 pp. $259.00. ISBN 3-540-26496-5.Bradley J. HollidayView Author Information The University of Texas at AustinCite this: J. Am. Chem. Soc. 2007, 129, 12, 3772–3773Publication Date (Web):March 3, 2007Publication History Published online3 March 2007Published inissue 1 March 2007https://pubs.acs.org/doi/10.1021/ja0697065https://doi.org/10.1021/ja0697065book-reviewACS PublicationsCopyright © 2007 American Chemical SocietyRequest reuse permissionsArticle Views209Altmetric-Citations1LEARN 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 SUBJECTS:Catalysts,Materials,Metals,Organometallic chemistry,Oxides Get e-Alerts
Studies in computer science: in honor of Samuel D. Conte (1994)

Traces the history of computer science at Purdue University, emphasizing the contributions of Conte, and discusses some of the topics that have interested him, such as numerical analysis, computational geometry, and software engineering. Seven of the 11 papers, from a November 1993 conference at Pur
Interaction of bovine blood clotting factor Va and its subunits with phospholipid vesicles (1983)

Thrombin-activated factor Va and factor Va subunit binding to large-volume vesicles was investigated by a technique based on the separation by centrifugation of phospholipid-bound protein from the bulk solution. This technique allows the direct measurement of free-protein concentration. It is concluded that the phospholipid binding site on factor Va is located on a basic factor Va subunit with Mr 80 000 (factor Va-LC). The effects of phospholipid vesicle composition, calcium concentration, pH, and ionic strength on the equilibrium constants of factor Va- and factor Va-LC-phospholipid interaction were studied. Factor Va and factor Va-LC binding to phospholipid requires the presence of negatively charged phospholipids. It is further demonstrated that the following occur: (a) Calcium ions compete with factor Va and factor Va-LC for phospholipid-binding sites. (b) The dissociation constant of protein-phospholipid interaction increases with the ionic strength, whereas the maximum protein-binding capacity of the phospholipid vesicle was not affected by ionic strength. (c) The dissociation constant for factor Va-phospholipid interaction depends on pH when the vesicle consists of phosphatidic acid. It is concluded that factor Va-phospholipid interaction is primarily electrostatic in nature, where positively charged groups on the protein directly interact with the phosphate group of net negatively charged phospholipids. The results suggest that factor Va, like factor Xa and prothrombin, has the characteristics of an extrinsic membrane protein.
Humoral Hypercalcemia of Malignancy in Canine Lymphosarcoma* (1988)

Studies on the pathogenesis of hypercalcemia in canine lymphosarcoma have led to conflicting results. The biochemical and bone histomorphometric findings in canine lymphosarcoma were examined in 19 hypercalcemic and 17 nonhypercalcemic dogs with lymphosarcoma. Compared to the nonhypercalcemic group, the hypercalcemic dogs demonstrated an increase in fasting and 24-h calcium excretion, an increase in fractional phosphorus excretion, and a significant increase in nephrogenous AMP excretion. Plasma 1,25-dihydroxyvitamin D and immunoreactive PTH levels were equivalent in the two groups. Quantitative bone histomorphometry performed on iliac crest biopsies revealed increased parameters of bone resorption in those hypercalcemic dogs with no evidence of tumor at the biopsy site, without a compensatory increase in bone formation. Acid-urea tumor tissue extracts from eight hypercalcemic and six nonhypercalcemic dogs were examined for adenylate cyclase-stimulating activity (ACSA). All tumors from hypercalcemic dogs contained ACSA, whereas none of the tumors from nonhypercalcemic dogs had ACSA. Further purification of one tumor extract yielded an adenylate cyclase-stimulating protein which appeared to interact specifically with the PTH receptor. We conclude that in some cases, hypercalcemia in canine lymphosarcoma is mediated by a tumor-derived circulating bone-resorbing factor which is distinct from PTH. ACSA detected in tumor tissue appears to be a reliable marker for the syndrome in vivo. The role of this activity in the pathogenesis of the syndrome remains to be determined.
Improved hepatic arterial fraction estimation using cardiac output correction of arterial input functions for liver DCE MRI (2016)

Liver dynamic contrast enhanced (DCE) MRI pharmacokinetic modelling could be useful in the assessment of diffuse liver disease and focal liver lesions, but is compromised by errors in arterial input function (AIF) sampling. In this study, we apply cardiac output correction to arterial input functions (AIFs) for liver DCE MRI and investigate the effect on dual-input single compartment hepatic perfusion parameter estimation and reproducibility. Thirteen healthy volunteers (28.7 ± 1.94 years, seven males) underwent liver DCE MRI and cardiac output measurement using aortic root phase contrast MRI (PCMRI), with reproducibility (n = 9) measured at 7 d. Cardiac output AIF correction was undertaken by constraining the first pass AIF enhancement curve using the indicator-dilution principle. Hepatic perfusion parameters with and without cardiac output AIF correction were compared and 7 d reproducibility assessed. Differences between cardiac output corrected and uncorrected liver DCE MRI portal venous (PV) perfusion (p = 0.066), total liver blood flow (TLBF) (p = 0.101), hepatic arterial (HA) fraction (p = 0.895), mean transit time (MTT) (p = 0.646), distribution volume (DV) (p = 0.890) were not significantly different. Seven day corrected HA fraction reproducibility was improved (mean difference 0.3%, Bland-Altman 95% limits-of-agreement (BA95%LoA) ±27.9%, coefficient of variation (CoV) 61.4% versus 9.3%, ±35.5%, 81.7% respectively without correction). Seven day uncorrected PV perfusion was also improved (mean difference 9.3 ml min<sup>-1</sup>/100 g, BA95%LoA ±506.1 ml min<sup>-1</sup>/100 g, CoV 64.1% versus 0.9 ml min<sup>-1</sup>/100 g, ±562.8 ml min<sup>-1</sup>/100 g, 65.1% respectively with correction) as was uncorrected TLBF (mean difference 43.8 ml min<sup>-1</sup>/100 g, BA95%LoA ±586.7 ml min<sup>-1</sup>/ 100 g, CoV 58.3% versus 13.3 ml min<sup>-1</sup>/100 g, ±661.5 ml min<sup>-1</sup>/100 g, 60.9% respectively with correction). Reproducibility of uncorrected MTT was similar (uncorrected mean difference 2.4 s, BA95%LoA ±26.7 s, CoV 60.8% uncorrected versus 3.7 s, ±27.8 s, 62.0% respectively with correction), as was and DV (uncorrected mean difference 14.1%, BA95%LoA ±48.2%, CoV 24.7% versus 10.3%, ±46.0%, 23.9% respectively with correction). Cardiac output AIF correction does not significantly affect the estimation of hepatic perfusion parameters but demonstrates improvements in normal volunteer 7 d HA fraction reproducibility, but deterioration in PV perfusion and TLBF reproducibility. Improved HA fraction reproducibility maybe important as arterialisation of liver perfusion is increased in chronic liver disease and within malignant liver lesions.