bluuebunny/crossref_metadata_2025_split huggingface dataset:
Designing the Folding Mechanics of Coiled Coils
Authors: Bornschlögl Thomas , Gebhardt J. Christof M. , Rief Matthias 
Published: September 2009

AbstractNaturally occurring coiled coils are often not homogeneous throughout their entire structure but rather interrupted by sequence discontinuities and non‐coiled‐coil‐forming subsegments. We apply atomic force microscopy to locally probe the mechanical folding/unfolding process of a well‐understood model coiled coil when unstructured subsegments with different sizes are added. We find that the refolding force decreases from 7.8 pN with increasing size of the added unstructured subsegment, while the unfolding properties of the model coiled coil remain unchanged. We show that this behavior results from the increased size of the nucleation seed which has to form before further coiled‐coil folding can proceed. Since the nucleation seed size is linked to the width of the energetic folding barrier, we are able to directly measure the dependence of folding forces on the barrier width. Our results allow the design of coiled coils with designated refolding forces by simply adjusting the nucleation seed size.
Stereochemical Studies of Ag‐Catalyzed Hosomi–Sakurai Reaction Using Chiral Silanes
Authors: Wadamoto Manabu , Naodovic Marina , Yamamoto Hisashi 
Published: September 2009

AbstractStereochemical aspect of asymmetric Ag‐catalyzed Hosomi–Sakurai reaction with ketones has been investigated. Several allyltrimethoxysilanes have been synthesized and used for the asymmetric reaction. Remarkably, among several possible diastereomers only two are generated with high levels of diastereo‐ and enantioselectivities. Based on the observations for different allyltrimethoxysilanes, we hypothesize formation of a single allylsilver species which undergoes addition to the ketone.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
O‐TMS‐α,α‐diphenyl‐(S)‐prolinol Modified with an Ionic Liquid Moiety: A Recoverable Organocatalyst for the Asymmetric Michael Reaction between α,β‐Enals and Dialkyl Malonates
Authors: Maltsev Oleg V. , Kucherenko Alexandr S. , Zlotin Sergei G. 
Published: September 2009

AbstractO‐TMS‐α,α‐diphenyl‐(S)‐prolinol derivative bearing an ionic liquid fragment was synthesized for the first time and proven to be an efficient catalyst for the asymmetric Michael reaction of aromatic α,β‐unsaturated aldehydes with dialkyl malonates. The prepared catalyst can be recovered four times and used in the same reaction without a decrease in activity or a decrease in the enantioselectivity of the reaction.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Features detection in spatial point processes via multivariate techniques
Authors: Mateu J. , Lorenzo G. , Porcu E. 
Published: September 2009

AbstractWe consider the problem of detecting features of general shape in spatial point processes in the presence of substantial clutter. Our goal is to remove clutter from images where one or several features are present and have to be detected. We use a method based on local indicators of spatial association (LISA) functions. Each LISA function is considered an observation in a multidimensional space. We thus perform cluster and multidimensional scaling to classify these observations, and in turn to discriminate between points belonging to the feature and clutter points. Two environmental problems based on forest fires and earthquakes are developed. Copyright © 2009 John Wiley & Sons, Ltd.
Application of the WEPP model for prioritization and evaluation of best management practices in an Indian watershed
Authors: Pandey A. , Chowdary V. M. , Mal B. C. , Billib M. 
Published: September 2009

AbstractThe pre‐calibrated and validated physically based watershed model, water erosion prediction project (WEPP) was used as a modelling tool for the identification of critical watersheds and evaluation of best management practices for a small hilly watershed (Karso) of India. The land use/cover of the study area was generated using IRS‐1C LISS‐III (linear imaging self scanner) satellite data. The watershed and sub‐watershed boundaries, drainage, slope and soil map of the study area were generated using ARC/INFO geographic information system (GIS). The WEPP model was finally applied to the Karso watershed which lies within Damodar Barakar catchment of India to identify the critical sub‐watersheds on the basis of their simulated average annual sediment yields. Priorities were fixed on the basis of ranks assigned to each critical sub‐watershed based on the susceptibility to erosion. The sub‐watershed having the highest sediment yield was assigned a priority number 1, the next highest value was assigned a priority number 2, and so on. Subsequently, the model was used for evaluating the effectiveness of best management practices (crop and tillage) for conservation of soil for all the sub‐watersheds. On the basis of this study, it is realized that cash crops like soyabean should be encouraged in the upland portion of the sub‐watersheds, and the existing tillage practice (country plough/mould board plough) may be replaced by a field cultivation system for conservation of soil and water in the sub‐watersheds. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis of magadiite using a natural diatomite material
Authors: Wang Yu , Shang Yunshuai , Zhu Jiang , Wu Jian , Ji Shouhua , Meng Changgong 
Published: September 2009

AbstractBACKGROUND: This study investigated the synthesis of magadiite from a natural diatomite material. The influence of key reaction parameters, including reaction time, temperature and molar ratios of Na2O/SiO2 and H2O/Na2O, on the formation of magadiite were investigated. The as‐synthesized magadiite was characterized by X‐ray powder diffraction, scanning electron microscopy, infrared spectroscopy, thermogravimetry and differential thermal analysis.RESULTS: The well crystallized magadiite with a rosette like morphology was prepared from a dispersion with the molar ratio H2O/Na2O = 28.15 and Na2O/SiO2 = 0.15 by heating at 160 °C for 42 h. The basal space of the synthesized magadiite is 15.5 Å and the stretching and bending frequencies of the SiO4 units making up the magadiite layer were recorded. The layered structure was destroyed when the temperature rose above 250 °C, and combining the results of thermogravimetry and differential thermal analysis suggested the structural alteration may be due to the condensation of silanol groups.CONCLUSION: Diatomite has been used to synthesize magadiite with a high purity and well crystallized. The cost of synthesis has been reduced allowing its use in conventional industrial applications, thus expanding the commercial utilization of diatomite. Copyright © 2009 Society of Chemical Industry
Sonography and fine‐needle aspiration biopsy in the diagnosis of benign versus malignant nodules in patients with autoimmune thyroiditis
Authors: Liu Feng‐Hsuan , Hsueh Chuen , Chang Hung‐Yu , Liou Miaw‐Jene , Huang Bie‐Yu , Lin Jen‐Der 
Published: September 2009

AbstractPurpose.To correlate sonographic (US) characteristics and results of fine‐needle aspiration biopsy (FNAB) of thyroid nodules in autoimmune thyroiditis (AT) with surgical pathological findings.Method.Forty AT patients with 40 nodular lesions were analyzed retrospectively. Five sonographic characteristics were recorded for each nodule: diameter, echogenicity, microcalcification, halo sign, and margin. Preoperative sonograms and FNAB results were compared with postoperative histopathological findings.Result.Twenty‐four of the 40 nodules were malignant, including 20 papillary carcinomas, 3 follicular carcinomas, and 1 medullary carcinoma. Of the 16 benign nodules, 8 were nodular hyperplasia, 6 lymphocytic thyroiditis, and 1 each follicular adenoma and Hürthle cell adenoma. The only US parameter that was significant in malignant vs. benign nodules was the presence of poorly defined margins. Based on preoperative cytology, 22 of the 23 malignant nodules were correctly diagnosed, and 10 of the 14 benign nodules were correctly identified. The positive predictive value was 78.6%, and the negative predictive value was 93.7%.Conclusion.No single US parameter can predict thyroid malignancy in patients with AT. A combination of US and FNAB provides the most sensitive and specific approach available preoperatively. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Characterisation of odour‐active compounds in lupin flour
Authors: Bader Stephanie , Czerny Michael , Eisner Peter , Buettner Andrea 
Published: September 2009

AbstractBACKGROUND: Lupin ingredients are promising alternatives to soybean products owing to their similarly high protein content. Lupin flour exhibits a green and bean‐like off‐flavour in higher amounts. The aim of this study was to characterise and identify the main odour‐active compounds in lupin flour.RESULTS: The orthonasal aroma of lupin flour was evaluated by means of aroma profile analysis and was found to be characterised by grassy‐green, metallic, fatty, fruity, hay‐like, cheese‐like, and meat‐like odour qualities. Volatile compounds of lupin flour of Lupinus angustifolius cv. Boregine were extracted with dichloromethane and isolated by solvent‐assisted flavour evaporation. Aroma extract dilution analysis (AEDA) was carried out with the obtained extract. In total, 50 odorants were detected by high‐resolution gas chromatography–olfactometry. AEDA revealed 26 odour‐active compounds with flavour dilution factors higher or equal to 32. The substances were unequivocally identified by their odour characteristics, their retention indices and their mass spectra using one‐dimensional or two‐dimensional gas chromatography–mass spectrometry, respectively.CONCLUSION: A series of unsaturated and saturated aldehydes, ketones, carboxylic acids, alkyl‐methoxypyrazines and terpenes were identified for the first time as odour‐active contributors to the aroma of lupin flour. Copyright © 2009 Society of Chemical Industry
Multi‐residue analysis of sulfonamides in animal tissues by capillary zone electrophoresis with electrochemical detection
Authors: Chu Qingcui , Zhang Dongli , Wang Jinyan , Ye Jiannong 
Published: September 2009

AbstractBACKGROUND: The objective of this study was to adapt and improve previously published analysis methods aimed at the simultaneous determination of sulfonamide residues in edible animal tissues by capillary zone electrophoresis with electrochemical detection.RESULTS: The effects of several factors such as the acidity and concentration of running buffer, the separation voltage, the applied potential and the injection time on CZE‐ED were investigated. Complete separation of six sulfonamides was achieved within 17 min by using 40 mmol L−1 Na2B4O7/25 mmol L−1 KH2PO4 (pH 6.2) at an applied voltage of 18 kV. Excellent linearity was obtained over two orders of magnitude with the improved detection limits (S/N = 3) ranged from 1.7 × 10−7 to 4.4 × 10−9 g mL−1 for all six sulfonamides in comparison with previous reports. A solvent extraction/centrifuge/evaporation procedure was used to extract sulfonamides from animal tissues, sample clean‐up and pre‐concentration of sulfonamides prior to CZE‐ED analysis. Good recoveries from 81% to 92% were achieved.CONCLUSION: Results obtained in this work indicated that the proposed CZE‐ED method was sensitive, rapid and simple for the simultaneous determination of sulfonamides in edible animal tissues. Therefore, the new faster and easy handling procedure provides an additional powerful tool that can be employed for the analysis of sulfonamide residues in foodstuff. Copyright © 2009 Society of Chemical Industry
Effect of temperature on the enantioselectivity of basic analytes using CE with sulfated β‐cyclodextrins
Authors: Peng Zhen‐Lei , Guo Baoyuan , Wei Weili , Li Haifang , Lin Jin‐Ming 
Published: September 2009

AbstractTwelve basic analytes, including ephedrine and its structurally related compounds, were used to study the influence of capillary temperature on enantioselectivity in CE enantioseparations under reversed polarity mode using sulfated β‐CD (S‐β‐CD) as chiral selectors. All of the effective mobility changes of (+)‐enantiomers between 35 and 20°C were higher than those of (–)‐enantiomers whosoever enantioselectivity increased or decreased with an increase in temperature. However, the unusual temperature effect that enantioselectivity was increased with an increase of temperature was observed for the compounds with hydroxyl substitution on phenyl ring and had relationship with the molecular structures. With performing NMR studies on the selected selector‐analyte complexes, the results led to a deeper understanding of the chiral discrimination process. Inspection of the complexation‐induced chemical shifts (CICS) of the enantiomers showed that the phenyl ring sits deeply and slantways in the cavity of S‐β‐CD and alkyl chain pointed out of the wider rim of S‐β‐CD with ion–ion and hydrogen bond interactions between analytes and S‐β‐CD.
Rapid determination of losartan and losartan acid in human plasma by multiplexed LC–MS/MS
Authors: Shah Hiten J. , Kundlik Mohan L. , Patel Nitesh K. , Subbaiah Gunta , Patel Dasharath M. , Suhagia Bhanubhai N. , Patel Chhagan N. 
Published: September 2009

AbstractA rapid LC–MS/MS method has been developed and validated for the determination of losartan (LOS) and its metabolite losartan acid (LA) (EXP‐3174) in human plasma using multiplexing technique (two HPLC units connected to one MS/MS). LOS and LA were extracted from human plasma by SPE technique using Oasis HLB® cartridge without evaporation and reconstitution steps. Hydroflumethiazide (HFTZ) was used as an internal standard (IS). The analytes were separated on Zorbax SB C‐18 column. The mass transition [M–H] ions used for detection were m/z 421.0 → 127.0 for LOS, m/z 435.0 → 157.0 for LA, and m/z 330.0 → 239.0 for HFTZ. The proposed method was validated over the concentration range of 2.5–2000 ng/mL for LOS and 5.0–3000 ng/mL for LA with correlation coefficient ⪈0.9993. The overall recoveries for LOS, LA, and IS were 96.53, 99.86, and 94.16%, respectively. Total MS run time was 2.0 min/sample. The validated method has been successfully used to analyze human plasma samples for applications in 100 mg fasted and fed pharmacokinetic studies.
Simultaneous enrichment and separation of neutral and anionic analytes through combining large volume sample stacking with sweeping in CE
Authors: Zhu Zai‐fang , Yan Na , Zhou Ximin , Zhou Lei , Chen Xingguo 
Published: September 2009

AbstractIn this work, we overcame the deficiencies of large volume sample stacking (LVSS) in separating low‐mobility and neutral analytes through combining LVSS with sweeping in CE, and employed this new approach to enrich and separate neutral and anionic analytes simultaneously. This technique was carried out with pressure injection of large‐volume sample followed by EOF as a pump pushing the bulk of low‐conductivity sample matrix out of the outlet of the capillary while analytes were swept by micelles and separated via MEKC without the electrode polarity switching. Careful optimization of the enrichment and separation conditions allowed the enrichment factors (EFs) of peak height and peak area of the analytes to be in the range of 9–33 and 21–35 comparing with the conventional injection mode, respectively. The five analytes were baseline separated in 15 min and the detection limits ranged from 26.5 to 55.8 ng/mL (S/N = 3). The developed method was successfully applied to determine adenine, caffeine, theophylline, reduced L‐glutathione (GSH) and oxidized L‐glutathione (GSSG) in two different teas with recoveries that ranged from 84.4 to 105.2%.
Capillary electrophoresis using core‐based hyperbranched polyethyleneimine (CHPEI) static‐coated capillaries
Authors: Boonyakong Cheerapa , Tucker Sheryl A. 
Published: September 2009

AbstractWith unique 3‐D architecture, the application of core‐based hyperbranched polyethyleneimine (CHPEI), as a capillary coating in capillary electrophoresis, is demonstrated by manipulation of the electroosmotic mobility (EOF). CHPEI coatings (CHPEI5, Mw ≈︂ 5000 and CHPEI25, Mw ≈︂ 25 000) were physically adsorbed onto the inner surface of bare fused‐silica capillary (BFS) via electrostatic interaction of the oppositely charged molecules by rinsing the capillaries with different CHPEI aqueous solutions. The EOF values of the coated capillaries were measured over the pH range of 4.0–9.0. At higher pH (pH >6) the coated capillary surface possesses excess negative charges, which causes the reversal of the EOF. The magnitudes of the EOF obtained from the coated capillaries were three‐fold lower than that of BFS capillary. Desirable reproducibility of the EOF with % RSD (n = 5) ⪇ 2 was obtained. Effect of ionic strength, stability of the coating (% RSD = 0.3) and the dependence of the EOF on pH (% RSD = 0.5) were also investigated. The CHPEI‐coated capillaries were successfully utilized to separate phenolic compounds, B vitamins, as well as basic drugs and related compounds with reasonable analysis time (<20 min) and acceptable migration‐time repeatability (<0.7% RSD for intra‐capillary and <2% RSD for inter‐capillary).
Analysis of polycyclic aromatic hydrocarbons in fish: evaluation of a quick, easy, cheap, effective, rugged, and safe extraction method
Authors: João Ramalhosa Maria , Paíga Paula , Morais Simone , Delerue‐Matos Cristina , Prior Pinto Oliveira Maria Beatriz 
Published: September 2009

AbstractQuEChERS method was evaluated for extraction of 16 PAHs from fish samples. For a selective measurement of the compounds, extracts were analysed by LC with fluorescence detection. The overall analytical procedure was validated by systematic recovery experiments at three levels and by using the standard reference material SRM 2977 (mussel tissue). The targeted contaminants, except naphthalene and acenaphthene, were successfully extracted from SRM 2977 with recoveries ranging from 63.5–110.0% with variation coefficients not exceeding 8%. The optimum QuEChERS conditions were the following: 5 g of homogenised fish sample, 10 mL of ACN, agitation performed by vortex during 3 min. Quantification limits ranging from 0.12–1.90 ng/g wet weight (0.30–4.70 μg/L) were obtained. The optimized methodology was applied to assess the safety concerning PAHs contents of horse mackerel (Trachurus trachurus), chub mackerel (Scomber japonicus), sardine (Sardina pilchardus) and farmed seabass (Dicentrarchus labrax). Although benzo(a)pyrene, the marker used for evaluating the carcinogenic risk of PAHs in food, was not detected in the analysed samples (89 individuals corresponding to 27 homogenized samples), the overall mean concentration ranged from 2.52 ± 1.20 ng/g in horse mackerel to 14.6 ± 2.8 ng/g in farmed seabass. Significant differences were found between the mean PAHs concentrations of the four groups.
Ultrafast UPLC‐ESI‐MS and HPLC with monolithic column for determination of principal flavor compounds in vanilla pods
Authors: Sharma Upendra K. , Sharma Nandini , Sinha Arun K. , Kumar Neeraj , Gupta Ajai P. 
Published: September 2009

AbstractIn this study, two novel chromatographic methods based on monolithic column high‐performance liquid chromatography (HPLC) and ultra‐performance liquid chromatography (UPLC) were developed for the ultrafast determination of principal flavor compounds namely vanillin, vanillic acid, p‐hydroxybenzoic acid, and p‐hydroxybenzaldehyde in ethanolic extracts of Vanilla planifolia pods. Good separation was achieved within 2.5 min using Chromolith RP18e column (100 mm×4.6 mm) for HPLC and Acquity BEH C‐18 (100 mm×2.1 mm, 1.7 μm) column for UPLC. Both methods were compared in terms of total analysis time, mobile phase consumption, sensitivity, and validation parameters like precision, accuracy, LOD, and LOQ. Further, system suitability test data including resolution, capacity factor, theoretical plates, and tailing factor was determined for both the methods by ten replicate injections. Monolithic column based HPLC gave better results for most of the selected parameters while UPLC was found to be more eco‐friendly with low mobile phase consumption and better sensitivity. Both methods may be used conveniently for the high throughput analysis of large number of samples in comparison to traditional particulate column.
Prediction of immobilized artificial membrane‐liquid chromatography retention of some drugs from their molecular structure descriptors and LFER parameters
Authors: Fatemi Mohammad Hossein , Shamseddin Hoda 
Published: September 2009

AbstractIn this work multiple linear regression (MLR) was carried out for the prediction of immobilized artificial membrane (IAM) retention factors of 40 basic and neutral drugs in two mobile phase compositions. We developed some MLR models by using linear free energy relationships (LFER) parameters and also theoretically derived molecular descriptor. Root mean square error of MLR model in prediction of log kwPBSIAM and kwMOPSIAM are 0.332 and 0.351, respectively, while these values are 0.371 and 0.500 for LFER models. Inspections to these values indicate that the statistical parameters of MLR models are better than LFER models. The credibility of MLR models was evaluated by using leave‐many‐out cross‐validation and y‐scrambling procedures. The results of these tests indicate the applicability of theoretically derived molecular descriptors and LFER parameters prediction of IAM retention of drugs.
Lanthanide Metal‐Organic Frameworks as Ziegler–Natta Catalysts for the Selective Polymerization of Isoprene
Authors: Vitorino Marta J. , Devic Thomas , Tromp Moniek , Férey Gérard , Visseaux Marc 
Published: September 2009

AbstractThe unprecedented ability of neodymium‐based metal organic frameworks (MOFs) as polymerisation pre‐catalysts towards isoprene is reported. Combined with methylaluminoxane (MAO) or modified MAO (MMAO), they afford mainly cis‐selective polyisoprene, up to 90.7%. Both the activity and the selectivity are tentatively ascribed to the intrinsic microstructure of the starting materials. Compared to conventional carboxylates, MOFs associated to an Al co‐catalyst are less active but the selectivity is found to be higher, and it may be modified by controlling the access to the pores, which would be favored at higher temperatures. Some residual crystalline MOF remains disseminated within the polymer matrix, as shown by X‐ray diffraction and X‐ray absorption spectroscopy studies.magnified image
Testase 1 (ADAM 24) a sperm surface metalloprotease is required for normal fertility in mice
Authors: Zhu Guo‐Zhang , Gupta Surabhi , Myles Diana Gold , Primakoff Paul 
Published: September 2009

AbstractADAM family members play important roles in various physiological and pathological processes, for example, fertilization, embryogenesis, neurogenesis, and development of asthma and arthritis (Primakoff and Myles, 2000. Trends Genet 16: 83–87; Edwards et al., 2008. Mol Aspects Med 29: 258–289). We previously reported that testase 1 (ADAM 24) is the first identified metalloprotease present on the surface of mature sperm. To investigate a potential role of testase 1 in fertilization, we generated testase 1 deficient mice. Testase 1 null male mice showed reduced fertility, producing only half the number of offspring when compared to wild‐type littermates. In a standard in vitro fertilization assay, we found that sperm lacking testase 1 gave rise to polyspermic fertilization, a phenotypic feature that might contribute to failure of normal embryo development due to polyaneuploidy. Furthermore, in vivo, we found that testase 1 null males produced a higher number of polyspermic embryos at the pronuclear stage. These findings suggest that testase 1 is a sperm plasma membrane component which contributes to the prevention of polyspermy at the level of the oocyte plasma membrane. Mol. Reprod. Dev. 76: 1106–1114, 2009. © 2009 Wiley‐Liss, Inc.