bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic signal prospecting using multiparameter measurements: the case study of the Gallic Site of Levroux
Authors: Pétronille M. , Thiesson J. , Simon F.‐X. , Buchsenschutz O. 
Published: August 2010

AbstractThe ‘magnetic signal’ that combines both the induced (Ji) and the remanent (Jr) magnetization is widely used in archaeological and pedological prospecting. Magnetic prospecting recording the lateral variations of the total magnetization is the most frequently used measurement before in‐phase magnetic susceptibility (Kph) and magnetic viscosity (Kqu) mapping. The work presented here brings together three types of prospecting technique: magnetic field survey and electromagnetic measurements with both frequency and time domain devices that measure magnetic susceptibility and viscosity respectively. The site studied, the Gallic town of Levroux (Indre, France), is particularly interesting because it includes features such as pits and ditches dug into the calcareous substratum partly filled with topsoil and with residues of different metallurgical and fire activities. The field results indicated anomalies with different types of characterization: (i) many compact features filled with magnetic, electrically conductive and minimally viscous materials; and (ii) elongated anomalies characterized by lower magnetic properties and electric conductivity but relatively higher magnetic viscosity than those of the compact features. In addition to the location of the features, the combination of the information brought by the different types of measurements allows us to evaluate the possible erosion of their upper parts by ploughing, to assess their depth (never deeper than 1.30 m) and to precise the nature of the feature's fill. Copyright © 2010 John Wiley & Sons, Ltd.
Can grass biomethane be an economically viable biofuel for the farmer and the consumer?
Authors: Smyth Beatrice M. , Smyth Henry , Murphy Jerry D. 
Published: August 2010

AbstractFarm incomes in Ireland are in decline and many farmers would operate at a loss in the absence of subsidies. Agriculture is responsible for 27% of Ireland's greenhouse gas emissions and is the largest contributing sector. Penetration of renewable energy in the heat and transport sectors is falling short of targets, and there is no clear plan for achieving them. The anaerobic digestion of grass to produce biogas or biomethane is put forward as a multifaceted solution, which could help meet energy and emissions targets, reduce dependence on imported energy, and provide additional farm income. This paper addresses the economic viability of such a system. Grass biogas/biomethane fares poorly under the current combined heat and power tariff structure, which is geared toward feedstock that attracts a gate fee. Tariff structures similar to those used in other countries are necessary for the industry to develop. Equally, regulation should be implemented to allow injection of biomethane into the gas grid in Ireland. Blends of natural gas and biomethane can be sold, offering a cost‐competitive green fuel. Sale as a renewable transport fuel could allow profitability for the farmer and savings for the consumer, but suffers due to the lack of a market. Under current conditions, the most economically viable outlet for grass biomethane is sale as a renewable heating fuel. The key to competitiveness is the existing natural gas infrastructure that enables distribution of grass biomethane, and the renewable energy targets that allow renewable fuels to compete against each other. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd
Invited reviewnative chemical ligation applied to the synthesis and bioengineering of circular peptides and proteins
Authors: Clark Richard J. , Craik David J. 
Published: August 2010

AbstractNative chemical ligation methodology developed in the laboratory of Stephen Kent is a versatile approach to the linkage of peptide fragments using a native peptide bond. It is readily adaptable to the task of joining the N‐ and C‐termini of peptides to produce cyclic molecules and we have used it for the cyclization of a range of disulfide‐rich peptides. Specifically, it has been valuable for the synthesis of cyclotides, naturally occurring peptides characterized by a head‐to‐tail cyclized backbone and a knotted arrangement of three conserved disulfide bonds. Cyclotides have a diverse range of biological activities, including anti‐HIV, antimicrobial, and insecticidal activities. They are ultrastable owing to their cyclic cystine knot motif, and native chemical ligation methodology has been invaluable in the synthesis of a range of native and modified cyclotides to explore their structure‐activity relationships and applications in drug design. Similar studies have also been applied to a smaller cyclic peptide produced in sunflower seeds, sunflower trypsin inhibitor‐1, which also shows promise as a template in drug design applications. We have also found native chemical ligation to be a valuable methodology for the cyclization of conotoxins, small disulfide‐rich peptides from the venoms of marine cone snails. Conotoxins target a range of ions channels and receptors and are exciting leads in drug design applications. The synthetic cyclization of conotoxins with peptide linkers stabilizes them and improves their biopharmaceutical properties. In summary, this article illustrates the use of native chemical ligation technology in the cyclization of cyclotides, sunflower trypsin inhibitor‐1, and conotoxins in our laboratory. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 414–422, 2010.
Toward fully synthetic, homogeneous glycoproteins: Advances in chemical ligation
Authors: Yuan Yu , Chen Jin , Wan Qian , Wilson Rebecca M. , Danishefsky Samuel J. 
Published: August 2010

AbstractTraditionally, in the pharma sciences, there has been an unstated but operative bifurcation into small molecules and biologics. Small molecules were seen to be, at the discovery level, in the province of chemistry, based on targets provided through biology. By contrast, “biologics” were seen to arise solely from the province of biology exploiting its accessible replicative mechanisms. Our laboratory has been dedicated to the proposition that explosive advances in chemical synthesis have been such as to render so called “biologics” as being accessible to chemical synthesis. In this article, we focus particularly on the area of glycopeptides. Chemical synthesis, in principle, offers an advantage, in that it can lead to homogeneous glycopeptides characterized by a single glycoform of the glycosidic domain mounted at a particular amino acid in the polypeptide domain. In support of this defining goal, a variety of new methods have been developed. The key problem addressed is that of ligation. In this article, we review how insights available from mechanistic organic chemistry have been used to create an imposing framework for the synthesis of structures which would, in an earlier day, have been seen to be strictly in the realm of chemically inaccessible “biologics”. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 373–384, 2010.
Synthesis of a GPI anchor module suitable for protein post‐translational modification
Authors: Schumacher Miria C. , Resenberger Ulrike , Seidel Ralf P. , Becker Christian F. W. , Winklhofer Konstanze F. , Oesterhelt Dieter , Tatzelt Jörg , Engelhard Martin 
Published: August 2010

AbstractEukaryotic cell surface proteins are often modified by a glycosylphosphatidylinositol (GPI) anchor. More than 200 of these post‐translationally altered proteins are presently known, a prominent example being the prion protein (PrP). Although the significance of the GPI anchor is well recognized, efforts to study its function are hampered due to its complex chemical nature, which combines hydrophilic glycosyl chains with hydrophobic lipid moieties. Here we describe a general method for the synthesis of a GPI‐anchored peptide containing an N‐terminal Cys. This module can be employed for the production of proteins containing a natural GPI anchor using expressed protein ligation. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 457–464, 2010.
NMR study of the structure and self‐association of core peptide in aqueous solution and DPC micelles
Authors: Zheng Gang , Torres Allan M. , Ali Marina , Manolios Nicholas , Price William S. 
Published: August 2010

AbstractCore peptide is a hydrophobic peptide derived from the T‐cell antigen receptor‐alpha chain (TCR‐α) transmembrane region with therapeutic potential. The mechanism by which the peptide inserts into the membrane, including any requirements to change conformational or association states during the insertion, is unclear. Here, the self‐association and secondary structure of Core peptide in aqueous solution and in dodecylphosphocholine (DPC) micelles were examined using various nuclear magnetic resonance (NMR) techniques. NMR diffusion measurements were performed on 0.05, 1, and 5 mM Core peptide in D2O. These samples had pH values varying from 3 to 4. A constant measured diffusion coefficient of ∼2 × 10−10 m2 s−1 was observed in these samples indicating that Core peptide was monomeric. Multidimensional NMR experiments (i.e., TOCSY and NOESY) revealed the formation of β‐strands in water at low pH and random coil in DPC micelles. The results of this study reveal that at relatively low pH, the insertion mechanism must involve Core peptide in the monomeric state but it undergoes a conformational transition during membrane insertion. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 177–180, 2011.
Identification of a potential modification site in human stromal cell‐derived factor‐1
Authors: Baumann Lars , Beck‐Sickinger Annette G. 
Published: August 2010

AbstractSelective modification of proteins is an important tool to study their function. However, it is still challenging to identify the best position to avoid a loss of activity. By using a 6‐nitroveratryl (Nvoc)‐modification approach, we facilitate the identification of a potential modification site as Nvoc can be removed in situ by UV irradiation and accordingly allows directly the comparison of the biological activity of the modified and the unmodified protein derived from the same precursor. As a test system, we used stromal cell‐derived factor‐1 (SDF‐1), which is involved in a wide range of physiological functions, mainly hematopoiesis and embryonic organ development. This chemokine is a potential candidate in regenerative medicine because of its capability to attract stem cells to distinct localizations. First, we synthesized the wildtype and the Nvoc‐modified C‐terminal segments SDF‐1(50–68) and studied their secondary structure formation by circular dichroism spectroscopy. By using the intein‐mediated purification with a affinity chitin binding tag system, we then expressed the peptide thioester M‐[A49]‐SDF‐1(1–49)‐MESNA recombinantly, in which the valine at position 49 was replaced by a more suitable alanine residue to allow improved cleavage and ligation. After ligation and refolding, the biological activity was proven in a cell‐based inositol phosphate accumulation assay prior and after Nvoc removal, which showed that neither the alanine 49 nor the attached Nvoc group impair the activity of the analog. The study shows that lysine 56 is a potential site to introduce labels site‐specifically in SDF‐1. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 771–778, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Synthesis of MUC1 glycopeptide thioesters and ligation via direct aminolysis
Authors: Wilkinson Brendan L. , Chun Candy K. Y. , Payne Richard J. 
Published: August 2010

AbstractMUC1 is a cell‐surface, epithelial glycoprotein that forms an essential protective barrier of cells and serves to modulate intercellular communication. During cancer progression, the dysregulation of glycosyltransferases, which serve to elongate cell‐surface glycans, leads to aberrant glycosylation patterns on this glycoprotein. This results in the presentation of well‐characterized, tumor‐associated carbohydrate antigens (TACAs) which represent important biomarkers for a range of epithelial cancers. The synthesis of well‐defined, multivalent MUC1 glycopeptide constructs bearing TACAs therefore represents a viable opportunity for the development of cancer vaccine candidates. We report herein the synthesis of a glycopeptide thioester, comprising the full eicosapeptide variable number tandem repeat (VNTR) region of MUC1, which was prepared bearing multiple copies of the cancer‐associated TNantigen. The glycopeptide thioester was prepared on the solid‐phase using two different methods on 2‐chlorotrityl chloride and sulfamylbutyryl resins. The solid‐phase assembly on 2‐chlorotrityl chloride resin, followed by thioesterification in solution, afforded the desired thioester in 4% yield over 41 linear steps. Likewise, the glycopeptide thioester was successfully prepared on sulfamylbutyryl resin using an activation and thiol‐release strategy in a 9% isolated yield. The resulting peptide thioester was successfully ligated to a deprotected MUC1 glycopeptide using the direct aminolysis ligation to afford a 5.8 kDa, 40 amino acid MUC1 glycopeptide bearing 10 copies of the TNantigen. This work represents an important step toward the immunological evaluation of multivalent MUC1 constructs. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96: 137–146, 2011.
Nε‐(thiaprolyl)‐lysine as a handle for site‐specific protein conjugation
Authors: Van de Vijver Pieter , Suylen Dennis , Dirksen Anouk , Dawson Philip E. , Hackeng Tilman M. 
Published: August 2010

AbstractIn this article, we introduce the use of a thiaproline‐modified lysine side‐chain [Lys(Thz)], as an unlockable handle that enables late‐stage, site‐selective modification of chemically synthesized proteins. The Lys(Thz) residue was incorporated into the murine chemokine RANTES to demonstrate its compatibility with Boc/Bzl solid phase peptide synthesis, native chemical ligation, and disulfide bond formation. After oxidative folding of the protein, the thiol was liberated under mild reaction conditions [0.2M hydroxylamine (NH2OH) or O‐methylhydroxylamine (MeONH2), pH 4] and was subsequently reacted with thiol‐selective tags. This side chain protection strategy enables the use of readily available thiol‐reactive probes for the modification of internally disulfide bonded proteins. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 465–474, 2010.
A rapid and simple RP‐HPLC method for quantification of kirenol in rat plasma after oral administration and its application to pharmacokinetic study
Authors: Song Xiao‐Li , Zhang Qing‐Ying , Wang Zhe‐Ming , Fu Hong‐Zheng , Qian Rui‐Qin 
Published: August 2010

AbstractA rapid and simple reverse‐phase high‐performance liquid chromatography (RP‐HPLC) was developed and validated for the quantification of kirenol in rat plasma after oral administration. Kirenol and darutoside (internal standard, IS) were extracted from rat plasma using Cleanert™ C18 solid‐phase extraction (SPE) cartridge. Analysis of the extraction was performed on a Thermo ODS‐2 Hypersil C18 reversed‐phase column with a gradient eluent composed of acetonitrile and 0.1% phosphoric acid. The flow rate was 1.0 mL/min and the detection wavelength was set at 215 nm. The calibration curve was linear over the range of 9.756–133.333 µg/mL (r2 = 0.9991) in rat plasma. The lower limits of detection and quantification were 2.857 and 9.756 µg/mL, respectively. The intra‐ and inter‐day precisions (relative standard deviation, RSD) were between 2.24 and 4.46%, with accuracies ranging from 91.80 to 102.74%. The extraction recovery ranged from 98.16 to 107.62% with RSD less than 4.81%. Stability studies showed that kirenol was stable in preparation and analytical process. The present method was successfully applied to the pharmacokinetic study of kirenol in male Sprague–Dawley rats after oral administration at a dose of 50 mg/kg. Copyright © 2010 John Wiley & Sons, Ltd.
RP‐HPLC‐DAD method for the estimation of embelin as marker in Embelia ribes and its polyherbal formulations
Authors: Madhavan Soumya N. , Arimboor Ranjith , Arumughan C. 
Published: August 2010

AbstractEvidence‐based herbal products with assured quality are assuming importance for complementary and alternative medicine. Traditional medicines by and large are not standardized and validated to meet the new requirements. In the present study, marker (embelin)‐based standardization of a major medicinal plant, Embelia ribes and its polyherbal formulations was attempted. Conditions for the quantitative extraction of the marker compound embelin from E. ribes fruits and herbal formulations were also optimized. Reversed‐phase high‐performance liquid chromatography, coupled with diode array detection (RP‐HPLC–DAD) for the quantification of embelin was developed and validated. Satisfactory results were obtained with respect to linearity (15–250 µg/mL), LOD (3.97 µg/mL), LOQ (13.2 µg/mL), recovery (99.4–103.8%) and precision (1.43–2.87%). The applicability of the method was demonstrated with selected phytopharmaceuticals. The present method was sensitive, accurate, simple and reproducible and therefore can be recommended for marker‐based standardization, and quality assurance of E. ribes herbal formulations. Copyright © 2010 John Wiley & Sons, Ltd.
Experimental Study on Flow Behavior in a Gas‐Solid Fluidized Bed for the Methanol‐to‐Olefins Process
Authors: Wang B. , Li T. , Sun Q.‐W. , Ying W.‐Y. , Fang D.‐Y. 
Published: August 2010

AbstractA cold model experimental system is established to investigate the flow behavior in a gas‐solid fluidized bed for the methanol‐to‐olefins process catalyzed by SAPO‐34. The system comprises a gas distributor in a F 300 × 5000 mm acrylic column, double fiber optic probe system and a series of cyclones. The experiments are carried out under conditions of atmospheric pressure and room temperature with different superficial velocities (0.3930–0.7860 m s–1) and different initial bed heights (600–1200 mm). The effects of radial distance, axial distance, superficial gas velocity, and initial bed height on the solid concentration and particle velocity in the bed are discussed. The time‐averaged solid concentration and rising particle velocity profiles under different conditions are obtained. The results show that an increase in the value of r/R or initial bed height results in an increase in the solid concentration but a decrease in the rising particle velocity in the dense phase area, while improvement of the superficial gas velocity has a negative influence on the solid concentration but results in an increase in the rising particle velocity.
Tunable Diastereoselection of Biased Rigid Systems by Lewis Acid Induced Conformational Effects: A Rationalization of the Vinylation of Cyclic Nitrones En Route to Polyhydroxylated Pyrrolidines
Authors: Delso Ignacio , Marca Eduardo , Mannucci Vanni , Tejero Tomás , Goti Andrea , Merino Pedro 
Published: August 2010

AbstractThe diastereofacial selection in addition reactions to biased rigid systems can be modulated by the action of Lewis acids. As an example, the stereoselectivity of the nucleophilic addition of vinyl magnesium bromide (VMB) to cyclic nitrones in the presence of diethylaluminum chloride (DEAC) shows a strong dependence on the temperature and the carbon substituent adjacent at the reaction center; it is remarkable that whereas a high selectivity is obtained at higher temperatures, in the presence of DEAC, a trend to invert the stereochemical course of the reaction is observed at lower temperatures, provided the substituent at C3 of the pyrrolidine ring allows delivery of the vinyl moiety. This behavior and difference in selectivity is to be attributed to the high conformational barriers of the intermediate nitroneDEACVMB complex. A clear inversion of the selectivity is observed at −78 °C for the reaction of the nitrone protected as an O‐methyl derivative. The present study provides a rationalization for the stereocontrolled addition of nucleophiles to rigid systems (cyclic nitrones).
ChemInform Abstract: The Constitution of PbF4 with Structure Refinement of SnF4.
Authors: BORK M. , HOPPE R. 
Published: August 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Electronic Structure, Superconductivity, and Substitution Patterns in Tl5Te3.
Authors: NORDELL K. J. , MILLER G. J. 
Published: August 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Basic Reaction Steps in the Sulfidation of Crystralline MoO3 to MoS2, as Studied by X‐Ray Photoelectron and Infrared Emission Spectroscopy.
Authors: WEBER TH. , MUIJSERS J. C. , VAN WOLPUT J. H. M. C. , VERHAGEN C. P. J. , NIEMANTSVERDRIET J. W. 
Published: August 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Polymer‐ and Dendrimer‐Bound Ti‐TADDOLates in Catalytic (and Stoichiometric) Enantioselective Reactions: Are Pentacoordinate Cationic Ti Complexes the Catalytically Active Species?
Authors: SEEBACH D. , MARTI R. E. , HINTERMANN T. 
Published: August 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Kinetic Resolution of sec‐Alcohols with Axially Chiral Twisted Amides.
Authors: YAMADA S. , OHE T. 
Published: August 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Sulfonylation and Phosphinylation of Olefinic Compounds with Radical Species Generated by the Oxidation of Sodium Sulfinates and Diphenylphosphine Oxide.
Authors: MOCHIZUKI T. , HAYAKAWA S. , NARASAKA K. 
Published: August 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Reaction of Dihalogenocarbenes with Functional Substituted Vinyl‐ and Allylacetylenic Compounds.
Authors: VELIEV M. G. , CHALABIEVA A. Z. , AKPEROVA E. G. , MAMEDOV I. M. , MAMEDOW E. SH. 
Published: August 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.