bluuebunny/crossref_metadata_2025_split huggingface dataset:
Total Synthesis of Siomycin A: Construction of Synthetic Segments
Authors: Mori Tomonori , Higashibayashi Shuhei , Goto Taiji , Kohno Mitsunori , Satouchi Yukiko , Shinko Kazuyuki , Suzuki Kengo , Suzuki Shunya , Tohmiya Hiraku , Hashimoto Kimiko , Nakata Masaya 
Published: May 2008

AbstractThe five practical segments for the total synthesis of siomycin A, that is, the dehydropiperidine segment A (5), the pentapeptide segment B (3), the dihydroquinoline segment C (6), and the β‐phenylselenoalanine dipeptide segments D (7) and E (4), were synthesized. Segment A (5) was constructed by the coupling of the azomethine ylide and the chiral sulfinimine, followed by the stereoselective reduction of the six‐membered imine function. Segment B (3) was synthesized by the phenylselenylation of the β‐lactone, stereoselective vinylzinc addition to the chiral sulfinimine, and oxazoline–thioamide conversion. Segment C (6) was prepared by the one‐pot olefination of the tetrahydroquinoline N‐oxide using triflic anhydride and triethylamine, stereoselective reduction of the methyl ketone function, and regioselective Yb(OTf)3‐catalyzed epoxide opening by the amino group. Segments D (7) and E (4) were synthesized by coupling of the properly protected β‐phenylselenoalanines.
Total Synthesis of Siomycin A: Completion of the Total Synthesis
Authors: Mori Tomonori , Higashibayashi Shuhei , Goto Taiji , Kohno Mitsunori , Satouchi Yukiko , Shinko Kazuyuki , Suzuki Kengo , Suzuki Shunya , Tohmiya Hiraku , Hashimoto Kimiko , Nakata Masaya 
Published: May 2008

AbstractThe total synthesis of siomycin A (1), a representative compound of the thiostrepton family of peptide antibiotics, was achieved by incorporating the five synthetic segments A (2), B (3), C (4), D (5), and E (6). The dehydropiperidine segment A (2) was esterified with the dihydroquinoline segment C (4), and the subsequent coupling with the β‐phenylselenoalanine dipeptide segment D (5) at the segment C portion followed by lactamization between the segments A and D gave segment A‐C‐D (27). This was amidated with the pentapeptide segment B (3) at the segment A portion followed by one‐pot cyclization (between segments A and B) and elongation (with the β‐phenylselenoalanine dipeptide segment E (6) at the segment A portion), thus furnishing siomycin A (1).
Catalytic Asymmetric Epoxidation of α,β‐Unsaturated Phosphane Oxides with a Y(O‐iPr)3/Biphenyldiol Complex
Authors: Hara Keiichi , Park So‐Young , Yamagiwa Noriyuki , Matsunaga Shigeki , Shibasaki Masakatsu 
Published: May 2008

AbstractA rare‐earth‐metal‐catalyzed asymmetric epoxidation of α,β‐unsaturated phosphane oxides is described. The appropriate selection of a chiral ligand and an achiral additive is important for achieving good reactivity and enantioselectivity. A Y(O‐iPr)3/biphenyldiol complex with an achiral phosphane oxide additive afforded β‐aryl α,β‐epoxy phosphane oxides in 77–99 % yield and with 96–98 % ee. With β‐alkyl substrates, the reaction proceeded smoothly in the absence of an achiral additive, and β‐alkyl α,β‐epoxy phosphane oxides were obtained in 94–99 % yield and with 87–95 % ee.
Gestaltung, Validierung und Optimierung von Messprogrammen für geotechnische Aufgabenstellungen
Authors: Schanz Tom , Meier Jörg 
Published: May 2008

AbstractBeim Entwurf von baubegleitenden Messprogrammen steht die Frage “Wo messe ich welche Größen wie häufig und mit welcher notwendigen Präzision?” im Mittelpunkt. Messprogramme sind kein Selbstzweck zur Anhäufung beliebig detaillierter und umfangreicher Daten, sondern dienen u.a. der quantitativen Beantwortung von Fragen nach der Gebrauchstauglichkeit und der Standsicherheit. Daraus leitet sich unmittelbar ein wesentlicher Abstimmungsbedarf zwischen den Verantwortlichen für die Gestaltung des Messprogramms und für die Durchführung der notwendigen Nachweise, und das im Vorfeld der eigentlichen Berechnungen, ab.Oben gestellte Frage kann erfolgreich mit den Methoden der angewandten Mathematik beantwortet werden. Zu quantifizieren ist dazu letztendlich die Sensitivität der Systemantwort (z. B. von Deformationen, Spannungen oder hydraulischen Potentialen) bezüglich häufig zunächst unbekannter Systemparameter, wie z. B. von Anfangs‐ und Randbedingungen, Geometrien oder Materialkennwerten.Eine umfassende messtechnische Instrumentierung ist heutzutage integraler Bestandteil der Mehrzahl aller “bedeutungsvollen” geotechnischen Projekte. Nicht zuletzt aufgrund immer anspruchsvollerer Vorhaben erweitert sich das Nutzungsgebiet der so gewonnenen Messdaten zunehmend von einer reinen Überwachung und Beweissicherung zu einem wichtigen Indikator für die Entscheidungsfindung im Rahmen der operativen Ausführung (im Sinne der “Beobachtungsmethode”). Um diese Nutzungsbereiche zu eröffnen, müssen die von Projekt zu Projekt unterschiedlich zu betrachtenden relevanten Aspekte der Systemantwort des jeweiligen Vorhabens in ausreichender Qualität und Umfang wiedergegeben werden. So ist grundsätzlich ein Messprogramm anzustreben, welches möglichst kosteneffizient ausreichende Daten zur Verfügung stellt.Da die Planung und Definition eines solchen Messprogramms i. d. R. bereits vor Beginn der eigentlichen Bauarbeiten abgeschlossen sein muss, ist dieser Arbeitsschritt als nicht‐trivial anzusehen. Als Lösungsweg bietet sich eine numerische Modellierung des Projektes an, wobei sowohl die geplanten Arbeitsschritte als auch verschiedene messtechnische Instrumentierungen an diesem Modell numerisch untersucht werden können. In diesem Beitrag wird eine Strategie für die Analyse von Messprogrammen in Kombination mit einem objektiven Bewertungskriterium vorgeschlagen.
Molecular Characterization of the NCoA‐1–STAT 6 Interaction
Authors: Seitz Markus , Maillard Ludovic T. , Obrecht Daniel , Robinson John A. 
Published: May 2008

AbstractMany protein–protein interactions involved in cell signalling, cell adhesion and regulation of transcription are mediated by short α‐helical recognition motifs with the sequence Leu‐Xaa‐Xaa‐Leu‐Leu (LXXLL, where Xaa is any amino acid). Originally observed in cofactors that interact with hormone‐activated nuclear receptors, LXXLL motifs are now known to occur in many transcription factors, including the STAT family, which transmit signals from activated cytokine receptors at the cell surface to target genes in the nucleus. STAT 6 becomes activated in response to IL‐4 and IL‐13, which regulate immune and anti‐inflammatory responses. Structural studies have revealed how an LXXLL motif located in 2.5 turns of an α‐helical peptide derived from STAT 6 provide contacts through the leucine side chains to the coactivator of transcription, NCoA‐1. However, since many protein–protein interactions are mediated by LXXLL motifs, it is important to understand how specificity is achieved in this and other signalling pathways. Here, we show that energetically important contacts between STAT 6 and NCoA‐1 are made in residues that flank the LXXLL motif, including the underlined residues in the sequence LLPPTEQDLTKLL. We also demonstrate how the affinity for NCoA‐1 of peptides derived from this region of STAT 6 can be significantly improved by optimising knobs‐into‐holes contacts on the surface of the protein. The results provide important new insights into the origins of binding specificity, and might be of practical value in the design of novel small‐molecule inhibitors of this important protein–protein interaction.
Using the eosin‐5‐maleimide binding test in the differential diagnosis of hereditary spherocytosis and hereditary pyropoikilocytosis
Authors: King May‐Jean , Telfer Paul , MacKinnon Heather , Langabeer Lisa , McMahon Corrina , Darbyshire Philip , Dhermy Didier 
Published: May 2008

AbstractBackground:Flow cytometric analysis of eosin‐5‐maleimide (EMA)‐labeled red blood cells (RBCs) has been used as a screening test for the diagnosis of patients with hereditary spherocytosis (HS). We assessed the fluorescence profiles for patients having HS and hereditary pyropoikilocytosis (HPP) together with their red cell indices.Methods:Flow cytometry was used to analyze EMA‐labeled RBCs. Membrane protein defects and spectrin variants were identified by SDS‐polyacrylamide gel electrophoresis.Results:An overlay of single fluorescence peaks for normal individuals, and those with HS and HPP revealed a graded fluorescence intensity (normal > HS > HPP). The area under each peak defined a specific RBC subpopulation; namely, normal RBCs, spherocytes, and microspherocytes. HS RBCs having a gross reduction in band 3 or spectrin content gave fluorescence readings almost as low as those for HPP. Complex fluorescence profiles were obtained for isolated HS and HPP cases.Conclusions:The mean cell volume is a useful discriminator for HS and HPP. We presented evidence that a mixed RBC population could occur in some HS and HPP patients, either in a transient manner or for a long‐term period. A differential diagnostic scheme for detecting HPP and HS by flow cytometry is proposed. © 2008 Clinical Cytometry Society
Monitoring cytomegalovirus IE‐1 and pp65‐specific CD4+ and CD8+ T‐cell responses after allogeneic stem cell transplantation may identify patients at risk for recurrent CMV reactivations
Authors: Gratama Jan W. , Brooimans Rik A. , van der Holt Bronno , Sintnicolaas Kees , van Doornum Gerard , Niesters Hubertus G. , Löwenberg Bob , Cornelissen Jan J. 
Published: May 2008

AbstractWe studied the recovery of CMV‐specific CD4+ and CD8+ T‐cell immunity in 52 recipients of allogeneic stem cell transplantation (SCT). The proportions of IFN‐γ‐producing CD4+ and CD8+ T cells upon in vitro activation using peptide pools representing the CMV pp65 and IE‐1 proteins were assessed at multiple time points post SCT, and correlated with the occurrence of CMV reactivation. In a retrospective analysis, recurrent CMV reactivations occurred in 9 patients and were associated with low pp65‐specific CD4+ T‐cell and low IE‐1‐specific CD8+ T‐cell reactivities, whereas patients without detectable CMV reactivation (n = 30) or a single reactivation (n = 13) showed a better recovery of these immune responses. CD4+ T‐cell responses to IE‐1 were infrequent in most patients, whereas CD8+ T‐cell responses to pp65 occurred frequently, but did not correlate with protection against (recurrent) reactivation. Prospectively, CMV‐specific T‐cell responses could be studied prior to 14 reactivation episodes in 8 patients. CD4+ T‐cell responses to IE‐1 and pp65 were positive in only 1 and 2 episodes, respectively. CD8+ T‐cell responses against IE‐1 were positive in 4, but against pp65 in 12 episodes, again showing that CD8+ T‐cell reactivity against pp65 did not prevent CMV reactivation. Thus, monitoring of particular CMV‐specific CD4+ and CD8+ T‐cell responses after allogeneic SCT may identify patients at risk for recurrent CMV reactivations. © 2008 Clinical Cytometry Society
Vascular disease and diabetes: is hypoglycaemia an aggravating factor?
Authors: Wright Rohana J. , Frier Brian M. 
Published: May 2008

AbstractAcute hypoglycaemia provokes profound physiological changes affecting the cardiovascular system and several haematological parameters, principally as a consequence of sympatho‐adrenal activation and counter‐regulatory hormonal secretion. Many of these responses have an important role in protecting the brain from neuroglycopenia, through altering regional blood flow and promoting metabolic changes that will restore blood glucose to normal. In healthy young adults the cardiovascular effects are transient and have no obvious detrimental consequences. However, some of the effected changes are potentially pathophysiological and in people with diabetes who have developed endothelial dysfunction, they may have an adverse impact on a vasculature that is already damaged. The acute haemodynamic and haematological changes may increase the risk of localized tissue ischaemia, and major vascular events can certainly be precipitated by acute hypoglycaemia. These include myocardial and cerebral ischaemia and occasionally infarction. Established diabetic retinopathy often deteriorates after strict glycaemic control is instituted, the latter being associated with a threefold increase in frequency of severe hypoglycaemia, and enhanced exposure to mild hypoglycaemia. The possible mechanisms underlying these hypoglycaemia‐induced effects include haemorrheological changes, white cell activation, vasoconstriction, and the release of inflammatory mediators and cytokines. The concept that acute hypoglycaemia could aggravate vascular complications associated with diabetes is discussed in relation to evolving comprehension of the pathogenesis of atherosclerosis and blood vessel disease. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of functionalized 1‐trimethylsiloxy‐substituted O‐trimethylsilyl alkylphosphonites and their derivatives
Authors: Prishchenko Andrey A. , Livantsov Mikhail V. , Novikova Olga P. , Livantsova Ludmila I. , Petrosyan Valery S. 
Published: May 2008

AbstractNucleophilic addition of trimethylsilyl esters of tricoordinate organophosphorus acids to various functionalized aldehydes with vinyl, aryl, and heterocyclic fragments is proposed as a convenient method for the synthesis of new 1‐trimethylsiloxysubstituted alkylphosphonites and their derivatives at mild conditions. Also the new functionalized derivatives of these phosphonites, including amino groups as well as certain properties of these compounds as important precursors of new functionalized 1‐hydroxyalkylorganophosphorus acids, are presented. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:352–359, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20430
Nucleophilic catalysis of phosphorus trichloride oxygen oxidation
Authors: Bezgubenko Ludmila V. , Pipko Sergey E. , Shalimov Alexandr A. , Sinitsa Anatoliy D. 
Published: May 2008

AbstractThe effect of nucleophilic catalysis on phosphorus trichloride oxygen oxidation is discovered. A number of nucleophilic catalysts for the phosphorus trichloride oxidation are found. Triethylamine, 4‐dimethylaminopyridine (DMAP), and tetramethylurea are amongst them. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:408–411, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20439
Reactions of tris(dimethylsilyl)methane and polymers containing si—h groups with various hydroxy compounds under aerobic and mild conditions
Authors: Safa Kazem D. , Tofangdarzadeh Shahin , Ayenadeh Hossein Heydari 
Published: May 2008

AbstractTris(dimethylsilyl)methane, (HMe2Si)CH, reacts with n‐propyl, iso‐propyl, n‐butyl, s‐butyl, iso‐butyl, n‐pentyl, s‐pentyl, n‐hexyl alcohol, and phenol in the presence of chloroplatinic acid (H2PtCl6ċ6H2O) in air to give products (ROMe2Si)3CH (where R is n‐propyl, iso‐propyl, n‐butyl, s‐butyl, iso‐butyl, n‐pentyl, s‐pentyl, n‐hexyl, phenyl). Similar reactions with benzyl alcohol and acetic acid lead to the unexpected products, (PhCH2)2O and HC(Me2SiOSiMe2)3CH, respectively. The compound (n‐BuOMe2Si)3CSiMe2H was made from (n‐BuOMe2Si)3CH by treatment with lithium diisopropylamide, followed by quenching with HMe2SiCl. The homopolymer poly{(4‐chloromethyl)styrene} and copolymers with styrene (in 1:1 and 1:3 mol ratio) were synthesized by free radical polymerization, and (HMe2Si)3C groups were linked to them by nucleophilic substitution reactions between (HMe2Si)3CLi and the chloromethyl groups of the polymer side chains. The resulting functional polymers containing Si—H bonds reacted with various alcohols in the presence of chloroplatinic acid under heterogeneous conditions. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:365–376, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20440
Silica‐supported ICl as a novel heterogeneous system for the rapid oxidation of urazoles to triazolinediones
Authors: Karami Bahador , Mallakpour Shadpour , Farahi Mahnaz 
Published: May 2008

AbstractICl–SiO2 as a new reactive system was prepared by the treatment of iodine monochloride with an activated silica gel in chloroform. ICl–SiO2 in a heterogeneous system efficiently oxidized urazoles to the corresponding triazolinediones under mild conditions in high yields at room temperature. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:389–393, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20444
Phosphorylated VEGFR2/KDR receptors are widely expressed in B‐cell non‐Hodgkin's lymphomas and correlate with hypoxia inducible factor activation
Authors: Giatromanolaki Alexandra , Koukourakis Michael I. , Pezzella Francesco , Sivridis Efthimios , Turley Helen , Harris Adrian L. , Gatter Kevin C. 
Published: May 2008

AbstractThe expression of hypoxia inducible factors (HIF) 1α and 2α, of vascular endothelial growth factor (VEGF) and of the phosphorylated form of its receptor VEGFR2 (pVEGFR2/KDR) were investigated immunohistochemically in a series of 146 B‐cell non‐Hodgkin's lymphomas and 48 normal lymph nodes. These proteins were significantly up‐regulated in neoplastic lymphocytes and a significantly higher expression of HIF1α (p = 0.05), VEGF (p = 0.02) and pVEGFR2/KDR (p = 0.007) was recorded in diffuse large B‐cell lymphomas(DLBCL) compared to follicular lymphomas (FL). A strong statistical association of pVEGFR2/KDR expression with high HIF1α, HIF2α and VEGF was noted in both DLBCL and FL. HIF1α andHIF2α were linked with VEGF expression but no association between HIF1α and HIF2α was noted. Vascular density was significantly higher in the lymphoma compared to normal tissue, but there was no association with any of the examined parameters. It is concluded that the VEGF/receptor pathway is active in more than half of NHLs and particularly in DLBCL. The intimate correlation of VEGF production with the presence of phosphorylated VEGF‐receptors strongly supports the concept of an autocrine pathway. The strong association of HIFαs with the expression of VEGF and pVEGFR2/KDR found in the study provide strong evidence on the role of HIFαs inthe activation of angiogenic and VEGF‐autocrine pathways that may be critical therapeutic targets for HIF‐inhibitors or other anti‐angiogenic agents. Copyright © 2008 John Wiley & Sons, Ltd.
Model data selection using gamma test for daily solar radiation estimation
Authors: Remesan R. , Shamim M. A. , Han D. 
Published: May 2008

AbstractHydrological modelling is a complicated procedure and there are many tough questions facing all modellers: what input data should be used? how much data is required? and what model should be used? In this paper, the gamma test (GT) has been used for the first time in modelling one of the key hydrological components: solar radiation. The study aimed to resolve the questions about the relative importance of input variables and to determine the optimum number of data points required to construct a reliable smooth model. The proposed methodology has been studied through the estimation of daily solar radiation in the Brue Catchment, the UK. The relationship between input and output in the meteorological data sets was achieved through error variance estimation before the modelling using the GT. This work has demonstrated how the GT helps model development in nonlinear modelling techniques such as local linear regression (LLR) and artificial neural networks (ANN). It was found that the GT provided very useful information for input data selection and subsequent model development. The study has wider implications for various hydrological modelling practices and suggests further exploration of this technique for improving informed data and model selection, which has been a difficult field in hydrology in past decades. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of subsurface drainage tiles on streamflow in Iowa agricultural watersheds: Exploratory hydrograph analysis
Authors: Schilling Keith E. , Helmers Matthew 
Published: May 2008

AbstractFlow from artificial subsurface (tile) drainage systems may be contributing to increasing baseflow in Midwestern rivers and increased losses of nitrate‐nitrogen. Standard hydrograph analysis techniques were applied to model simulation output and field monitoring from tile‐drained landscapes to explore how flow from drainage tiles affects stream baseflow and streamflow recession characteristics. DRAINMOD was used to simulate hydrologic response from drained (24 m tile spacing) and undrained agricultural systems. Hydrograph analysis was conducted using programs PART and RECESS. Field monitoring data were obtained from several monitoring sites in Iowa typical of heavily drained and less‐drained regions. Results indicate that flow from tile drainage primarily affects the baseflow portion of a hydrograph, increasing annual baseflow in streams with seasonal increases primarily occurring in the late spring and early summer months. Master recession curves from tile‐drained watersheds appear to be more linear than less‐tiled watersheds although comparative results of the recession index k were inconsistent. Considering the magnitude of non‐point source pollutant loads coming from tile‐drained landscapes, it is critical that more in‐depth research and analysis be done to assess the effects of tile drainage on watershed hydrology if water quality solutions are to be properly evaluated. Copyright © 2008 John Wiley & Sons, Ltd.
Estrogen receptor β deficiency enhances small intestinal tumorigenesis in ApcMin/+ mice
Authors: Giroux Véronique , Lemay Frédéric , Bernatchez Gérald , Robitaille Yolaine , Carrier Julie C. 
Published: May 2008

AbstractClinical evidence suggests that estradiol replacement therapy reduces colon cancer risk in ‘post’menopausal women. In colon epithelial cells, the estrogen receptor β (ERβ) is the predominant ER subtype and is thought to mediate the genomic effect of estrogens. The first aim of this study was to investigate the consequence of ERβ deficiency on intestinal tumorigenesis in the ApcMin/+ mouse model. Furthermore, to explore the biological mechanisms by which estrogens may influence the pathogenesis of colorectal cancer, we performed gene expression profiles in colonocytes from ovariectomized wild‐type (WT) vs. ERβ−/− mice, treated with estradiol (E2) or vehicle. Specifically in female, ERβ deficiency was found to be associated with higher adenoma multiplicity in the small intestine, but not in the colon. Furthermore, tumors from ERβ−/−ApcMin/+ female mice were on average significantly larger than those from control ApcMin/+ mice. Higher steady‐state proliferation in epithelial cells of the jejunum and colon from ERβ−/−ApcMin/+ vs. ApcMin/+ female mice was confirmed by BrdU incorporation assay. Interestingly, functional categorization of microarray results revealed the TGFβ signaling pathway to be modulated in colonocytes, especially for the WT + E2 vs. WT + Vehicle and the ERβ−/− + E2 vs. WT + E2 comparisons. Using quantitative PCR analysis, we observed transcripts from ligands of the TGFβ pathway to be upregulated in colonocytes from E2‐treated WT and ERβ−/− mice and downregulated in ERβ‐deficient mice, mostly in an E2‐independent manner. Therefore, our results demonstrate that ERβ deficiency enhances small intestinal tumorigenesis and suggest that modulation of the TGFβ signaling pathway could contribute to the protective role of estrogens on intestinal tumorigenesis. © 2008 Wiley‐Liss, Inc.