bluuebunny/crossref_metadata_2025_split huggingface dataset:
Online coupling of thin layer chromatography with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry: synthesis and application of a new material for the identification of carbohydrates by thin layer chromatography/matrix free material enhanced laser desorption/ionization mass spectrometry
Authors: Qureshi Muhammad Nasimullah , Stecher Guenther , Huck Christian , Bonn Guenther K. 
Published: September 2010

AbstractThis article describes the online hyphenation of thin layer chromatography with matrix free material enhanced laser desorption/ionization mass spectrometry (mf‐MELDI‐MS), the preparation of new material for MELDI and application of this newly synthesized material using TLC/MELDI‐MS for the analysis of carbohydrate reference standards and plant extracts. Samples included within these analyses are standard solutions of glucose, sucrose, raffinose and a plant extract of Quercus robur, which is used for its anti‐inflammatory, anti‐viral and anthelminitc properties in phytomedicine.A new material for mf‐MELDI‐MS is prepared by immobilizing bradykinin – a peptide, on silica gel coupled to 4‐(3‐triethoxysilylpropylureido)azobenzene. This modification enables the absorption of laser energy sufficient for desorption and ionization of low molecular weight molecules like carbohydrates and amino acids. The newly synthesized material delivered excellent results in respect to signal‐to‐noise (S/N) ratio (S/N ratio: >9/1) and sensitivity (limit of detection (LOD): lower to ng/µL). Hyphenation of TLC to MELDI‐MS employing the novel developed material simultaneously as chromatographic and mass spectrometric sorbent was shown for the first time for the analysis of low molecular weight molecules like mono‐ and oligosaccharides. Copyright © 2010 John Wiley & Sons, Ltd.
Toxicological determination andin vitrometabolism of the designer drug methylenedioxypyrovalerone (MPDV) by gas chromatography/mass spectrometry and liquid chromatography/quadrupole time‐of‐flight mass spectrometry
Authors: Strano‐Rossi Sabina , Cadwallader Amy B. , de la Torre Xavier , Botrè Francesco 
Published: September 2010

AbstractA method for the toxicological screening of the new designer drug methylenedioxypyrovalerone (MDPV) is described; with an emphasis on its application for anti‐doping analysis. The metabolism of MDPV was evaluatedin vitrousing human liver microsomes and S9 cellular fractions for CYP450 phase I and uridine 5′‐diphosphoglucuronosyltransferase (UGT) and sulfotransferase (SULT) phase II metabolism studies. The resulting metabolites were subsequently liquid/liquid extracted and analyzed using gas chromatography/mass spectrometry (GC/MS) as trimethylsilyl (TMS) derivatives. The structures of the metabolites were further confirmed by accurate mass measurement using a liquid chromatography/quadrupole time‐of‐flight (LC/QTOF) mass spectrometer. The studies demonstrated that the main metabolites of MDPV are catechol and methyl catechol pyrovalerone, which are in turn sulfated and glucuronated. The method for the determination of MDPV in urine has been fully validated by assessing the limits of detection and quantification, linearity, repeatability, and accuracy. This validation demonstrates the suitability for screening of this stimulant substance for anti‐doping and forensic toxicology purposes. Copyright © 2010 John Wiley & Sons, Ltd.
Complex palytoxin‐like profile of Ostreopsis ovata. Identification of four new ovatoxins by high‐resolution liquid chromatography/mass spectrometry
Authors: Ciminiello Patrizia , Dell'Aversano Carmela , Iacovo Emma Dello , Fattorusso Ernesto , Forino Martino , Grauso Laura , Tartaglione Luciana , Guerrini Franca , Pistocchi Rossella 
Published: September 2010

AbstractOver the past decades, Italian coastlines have been plagued by recurring presence of the benthic dinoflagellate Ostreopsis ovata. Such an alga has caused severe sanitary emergencies and economic losses due to its production of palytoxin‐like compounds. Previous studies have confirmed the presence of ovatoxin‐a (OVTX‐a) as the major toxin of the algal toxin profile together with small amounts of putative palytoxin (PLTX). In our ongoing research on O. ovata toxins we report herein on in‐depth investigation of an O. ovata culture carried out by high‐resolution (HR) liquid chromatography/mass spectrometry (LC/MS) and tandem mass spectrometry (MS2). Particularly, the presence of putative PLTX and OVTX‐a was confirmed and the occurrence in the extract of four new palytoxin‐like compounds, OVTX‐b, ‐c, ‐d, and ‐e, was highlighted. Elemental formulae have been assigned to the new ovatoxins and information has been gained about their structural features. A quantitative study of the O. ovata culture extract indicated that the whole of the new ovatoxins represents about 46% of the total toxin content and, thus, their presence has to be taken into account when LC/MS‐based monitoring programs of either plankton or contaminated seafood are carried out. Copyright © 2010 John Wiley & Sons, Ltd.
Quantitative analysis of positional isomers of triacylglycerols via electrospray ionization tandem mass spectrometry of sodiated adducts
Authors: Herrera Lisandra Cubero , Potvin Michael A. , Melanson Jeremy E. 
Published: September 2010

AbstractHerein we report a reversed‐phase high‐performance liquid chromatography tandem mass spectrometry (RP‐HPLC/MS/MS) method for the analysis of positional isomers of triacylglycerols (TAGs) in vegetable oils. The fragmentation behavior of [M + X]+ ions (X = NH4, Li, Na or Ag) was studied on a quadrupole‐time‐of‐flight (Q‐TOF) mass spectrometer under low‐energy collision‐induced dissociation (CID) conditions. Mass spectra that were dependent on the X+ ion and the nature and position of the acyl substituents were observed for four pairs of 'AAB/ABA'‐type TAGs, namely PPO/POP, OOP/OPO, LLO/LOL and OOL/OLO (where P is 16:0, palmitic acid; O is 18:1, oleic acid; and L is 18:2, linoleic acid). For the majority of [M + X]+ adducts, the loss of the fatty acid in the outer positions (sn‐1 or sn‐3) was favored over the loss in the central position (sn‐2), which enabled the determination of the fractional abundance of the isomers. Ratios of the intensity of fragment ions at various AAB/ABA compositions produced linear calibration curves with positive slopes, comparable to those obtained traditionally by ESI‐MS/MS of [M + NH4]+ adducts. The only exceptions were the [M + Ag]+ adducts of the PPO/POP system, which produced calibration curves with negative slopes. Sodium adducts provided the most consistent level of isomeric discrimination for the TAGs studied and also offered the most convenience in that they required no additive to the mobile phase. Therefore, calibration curve data derived from [M + Na]+ adducts were applied to the quantification of TAG regioisomers in sunflower and olive oils. The regiospecific analysis showed that palmitic acid was typically located at positions sn‐1 or sn‐3, whereas unsaturated fatty acids, oleic and linoleic acids were mostly found at the sn‐2 position. Copyright © 2010 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Bayesian network models for environmental flow decision making in the Daly River, Northern Territory, Australia
Authors: Chan Terence U. , Hart Barry T. , Kennard Mark J. , Pusey Bradley J. , Shenton Will , Douglas Michael M. , Valentine Eric , Patel Sandeep 
Published: September 2010

ABSTRACTThis paper reports the development and application of two Bayesian Network models to assist decision making on the environmental flows required to maintain the ecological health of the Daly River (Northern Territory, Australia). Currently, the Daly River is unregulated, with only a small volume of water extracted annually for agriculture. However, there is considerable pressure for further agricultural development in the catchment, particularly with demand for extra water extraction during the dry season (May–November).The abundances of two fish species—barramundi (Lates calcarifer) and sooty grunter (Hephaestus fuliginosus)—were chosen as the ecological endpoints for the models, which linked dry season flows to key aspects of the biology of each species. Where available, data were used to define flow–fish habitat relationships, but most of the relationships were defined by expert opinion because of a lack of quantified ecological knowledge.Recent field data on fish abundances were used to validate the models and gave prediction errors of 20–30%. The barramundi model indicated that the adult sub‐population was key to overall fish abundance, with this sub‐population particularly impacted by the timing of abstraction (early vs. late dry season). The sooty grunter model indicated that the juvenile sub‐population dominated the overall abundance and that this was primarily due to the amount of hydraulically suitable riffle habitat. If current extraction entitlements were fully utilized, the models showed there would be significant impacts on the populations of these two fish species, with the probability of unacceptable abundances increasing to 43% from 25% for sooty grunter and from 36% for barramundi under natural conditions. Copyright © 2010 John Wiley & Sons, Ltd.
Using Rasch theory to guide the practice of survey development and survey data analysis in science education and to inform science reform efforts: An exemplar utilizing STEBI self‐efficacy data
Authors: Boone William J. , Townsend J. Scott , Staver John 
Published: September 2010

AbstractOver many decades, science education researchers have developed, validated, and used a wide range of attitudinal instruments. Data from such instruments have been analyzed, results have been published, and public policies have been influenced. Unfortunately, most science education instruments are not developed using a guiding theoretical measurement framework. Moreover, ordinal‐level attitudinal data are routinely analyzed as if these data are equal interval, thereby violating requirements of parametric tests. This paper outlines how researchers can use Rasch analysis to develop higher quality science education instruments and why researchers must use Rasch analysis to prepare appropriate ordinal‐level data for parametric analyses. Detailed recommendations are set forth to help science education researchers increase the rigor of attitudinal instrument development and analysis. Suggestions are also set forth regarding how philosophical and analytical Rasch techniques align with broad goals of the science education research community. © 2010 Wiley Periodicals, Inc. Sci Ed 95:258–280, 2011
Neuronatin Promotes Neural Lineage in ESCs via Ca2+ Signaling
Authors: Lin Hsuan-Hwai , Bell Esther , Uwanogho Dafe , Perfect Leo W. , Noristani Harun , Bates Thomas J. D. , Snetkov Vladimir , Price Jack , Sun Yuh-Man 
Published: September 2010

Abstract
Neural induction is the first step in the formation of the vertebrate central nervous system. The emerging consensus of the mechanisms underling neural induction is the combined influences from inhibiting bone morphogenetic protein (BMP) signaling and activating fibroblast growth factor (FGF)/Erk signaling, which act extrinsically via either autocrine or paracrine fashions. However, do intrinsic forces (cues) exist and do they play decisive roles in neural induction? These questions remain to be answered. Here, we have identified a novel neural initiator, neuronatin (Nnat), which acts as an intrinsic factor to promote neural fate in mammals and Xenopus. ESCs lacking this intrinsic factor fail to undergo neural induction despite the inhibition of the BMP pathway. We show that Nnat initiates neural induction in ESCs through increasing intracellular Ca2+ ([Ca2+]i) by antagonizing Ca2+-ATPase isoform 2 (sarco/endoplasmic reticulum Ca2+-ATPase isoform 2) in the endoplasmic reticulum, which in turn increases the phosphorylation of Erk1/2 and inhibits the BMP4 pathway and leads to neural induction in conjunction with FGF/Erk pathway.
Antipsychotic‐induced DRD2 upregulation and its prevention by α‐lipoic acid in SH‐SY5Y Neuroblastoma cells
Authors: Deslauriers Jessica , Lefrançois Marilou , Larouche Annie , Sarret Philippe , Grignon Sylvain 
Published: September 2010

AbstractMost antipsychotic (AP) drugs are dopamine (DA) D2 receptor (DRD2) antagonists and remain the main pharmacological treatment of schizophrenia. Long‐term AP use can give rise to tardive dyskinesia. It has been reported that chronic treatment with APs induces DRD2 upregulation and oxidative stress, which have been associated with tardive dyskinesia. We showed previously that H2O2‐induced oxidative stress increased DRD2 expression in human SH‐SY5Y neuroblastoma cells. We report here the effects of AP drugs on DRD2 expression levels in the same cell line and the effects of the inhibition of oxidative phenomena by (±)‐α‐lipoic acid treatment. Haloperidol, a first‐generation AP, induced an increase in DRD2 protein and mRNA levels, whereas amisulpride, a second‐generation AP, had no significant effect. (±)‐α‐Lipoic acid pretreatment reversed the haloperidol‐induced DRD2 upregulation in mRNA and protein levels. Furthermore, haloperidol induced a larger increase of oxidative stress biomarkers (protein carbonylation, lipid peroxidation, and superoxide anion production) than amisulpride. (±)‐α‐Lipoic acid also attenuated AP‐induced oxidative stress. Inhibition of catecholamine synthesis by α‐methyl‐DL‐tyrosine (AMPT) increased DRD2 expression and prevented further increase by APs. Our results suggest that haloperidol‐induced DRD2 upregulation is linked to oxidative stress and provide potential mechanisms by which (±)‐α‐lipoic acid can be considered as a therapeutic agent to prevent and treat side effects related to the use of first‐generation APs. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
Rhodium‐catalyzed restructuring of carbon frameworks
Authors: Murakami Masahiro 
Published: September 2010

AbstractMetal‐catalyzed reactions involving an elementary step which cleaves a carbon‐carbon bond provide unique organic transformations. Restructuring reactions recently developed in our laboratory, through which the carbon framework of a starting substance is restructured into a totally different carbon framework, are discussed, with the possibility of applying such methods to the synthesis of natural products. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 326–331; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000023
Dekontamination von Vakuumpumpen und Komponenten aus der Halbleiter‐ und Elektronikindustrie
Authors: Karges Jürgen , Lamprecht Robert , Schneider Hans‐Walter 
Published: September 2010

AbstractDie Sicherheit der Mitarbeiter, der Umweltschutz und die Produktqualität: der reparierten Pumpen stehen im Mittelpunkt einer neuen Dekontaminierungsanlage für Vakuumpumpen und ‐komponenten aus den Halbleiterprozessen.Die Dekontamination und Wartung dieser Vakuumpumpen ist mit erheblichen Risiken verbunden. Die sich in den Pumpen befindenden toxischen Substanzen dürfen unter keinen Umständen in die Umgebung abgegeben werden. Einmalig in Europa ist die hier beschriebene Dekontaminationsanlage in der Nähe Münchens. Verschiedene Spezialfirmen fertigten Vorrichtungen und Maschinen nach speziellen Erfordernissen.Darüber hinaus wurden mit dem Hygiene‐Institut der Justus‐Liebig‐Universität in Giessen neue Wege der wissenschaftlichen und hygiene‐technischen Beratung von der Planung bis zur Abnahme der Anlage beschritten. Die Dekontaminierungsanlage mußte den strengen deutschen Umweltkriterien der Gewerbeaufsichtsämter und Umweltämter genügen.
Ausbau eines Sektormagnet‐RGA zu einem PC‐gestützten quantitativen Massenspektrometer
Authors: Solomon George M. , Schaefer Martin , Schaefer Klaus A. 
Published: September 2010

AbstractMit sorgfältiger Auslegung des Einlaßsystems und Eichung vor Ort werden Restgasanalysengeräte (RGAs) zu einem wichtigen Werkzeug für die quantitative Gasanalyse. Bisher denkt man bei RGAs in erster Linie an “billige und schmutzige” qualitative Geräte zur Lecksuche und/oder Nachweis von Verunreinigungen in Vakuumsystemen. In dieser Arbeit werden die Konstruktionsmerkmale für ein Einlaßsystem zu einem RGA diskutiert, wenn daraus ein quantitatives Massenspektrometer gemacht werden soll. Hierzu gehören schnelle Ansprechzeit ohne Entmischung der Probe, Eichstandards vor Ort, Vielfach‐Probeentnahmestellen und Fernbedienung. PC‐Steuerung für das Einlaßsystem und das RGA ergibt wichtige Eigenschaften wie automatisches Tunen der Peak‐Position, Dekonvolution der Spektren, Gemischanalyse basierend auf aktuellen Eichgasen, automatisches Ansteuern der Probenahmestelle in wahlweiser Reihenfolge und Datenspeicherung. Es werden Anwendungsbeispiele für solche integrierten Einlaßsysteme für industriellen und Forschungs‐Einsatz gegeben, wobei kontinuierliche Überwachung und automatische Eichung vorliegen.Alle Massenspektrometer‐/RGA‐Einlaßsysteme beruhen auf den gleichen Subsystemen wie: Pumpstand mit Hochvakuumpumpe und Vorpumpe, das eigentliche Massenfilter mit dem Probenahmekopf, Steuerelektronik und Display, Einlaßventile und Durchflußbegrenzer, eventuell noch zusätzlich eine Probenahme‐Vorpumpe. Obwohl diese Bauteile sich im allgemeinen gleichen, werden oft kleine Einzelheiten des Einlaßsystems übersehen, so daß die einfacheren und damit billigeren Einlaßsysteme sich nicht für quantitative Gasanalysen eignen. Diese Arbeit beschäftigt sich vor allem mit diesen wichtigen Details, die bei der Auslegung eines Massenspektrometer‐Einlaßsystems zu beachten sind.
Lipophile Kronenverbindungen — selektive Extraktionsmittel für Metallionen; Syntheseprinzipien
Authors: Beger Jörg , Gloe Karsten 
Published: September 2010

AbstractLipophilic crown ethers are useful for metal ion extraction: they are soluble in organic phases and insoluble in aqueous ones. The lipophilicity can be enhanced by long‐chain hydrocarbon residues, by expanding the carbon content in the crown skeleton and by other structural variations.The complexation behaviour and, therefore, the selectivity of crowns in extraction processes can be altered by changing the crown diameter, the kind and the number of hetero atoms within the crown ring or at positions outside the cycle. Furthermore, for the electro‐neutrality of the extracted species it is necessary to transfer also an anion into the organic phase. This problem can be solved with crown ether acids or with other hydrophobic inorganic or organic anions.In this review with 276 references many synthetic routes and examples of such lipophilic crown ethers are described. Special attention is given to the building blocks for the crown ethers, which are important in the extraction area. So the survey should open a view for similar syntheses of new metal extraction reagents with coronand structure.
Reaktionen trivalenter Phosphorverbindungen mit tert‐Butoxylradikalen
Authors: Schwetlick Klaus , Pionteck Jürgen , König Thomas , Rüger Claus 
Published: September 2010

AbstractThe products of the reaction of several alkyl, aryl, sterically hindered aryl and cyclic phosphites, thiophosphites, benzenephosphonites and triphenylphosphine with tert‐butoxyl radicals generated by thermolysis of di‐tert‐butyl peroxalate (DTBPO) in chlorobenzene at 50°C was studied.Alkyl phosphites are oxidized to the corresponding phosphates by β‐scission of the intermediate phosphoranyl radicals. Phenyl phosphites react under displacement of a phenoxyl to give tert‐butyl phosphites by α‐scission of the intermediate phosphoranyl radicals. Sterically hindered p‐methyl‐phenyl phosphites also form the tert‐butyl phosphites accompanied by rearranged p‐hydroxyphenylmethanephosphonates. Cyclic arylene phosphites are predominantly oxidized, substitution takes place to a minor extent.Benzenephosphonites and phosphines react with tert‐butoxyl radicals by oxidation to give the corresponding phosphonates and phosphine oxide, resp.Those phosphorus compounds which are oxidized with the formation of tert‐butyl radicals accelerate the thermal decomposition of DT BPO under the condition studied.
Metallclusterverbindungen  Chemie und Bedeutung Synthese, Struktur, Bindung
Authors: Walther Bernhard 
Published: September 2010

AbstractThe chemistry of metal cluster compounds has grown very rapidly during the last two decades mainly as a field of inorganic chemistry but other areas of chemistry too have made considerable contributions. More recently metal clusters have become of interest for different sciences, including physics, material sciences, biochemistry, and there is a strong search for practical applications. The article describes different synthetic strategies and methods for metal cluster compounds with metals in low oxidation states. The structure and bonding of low nuclearity clusters (M3 to M6) including their transformations in dependence of the electron count are discussed. There is a breakdown of the 18 electron rule observed for clusters containing six and more metal atoms and hence electron counting procedures like the Wade rules become helpful to predicting and remembering the structures of cluster compounds.
Über die Bestimmung von Spurenverunreinigungen in reiner Borsäure durch Extraktion‐Flammen‐AAS und Spektralphotometrie und über die Verwendung von White‐spirit als organisches Lösungsmittel in der Extraktion‐Flammen‐AAS
Authors: Arpadjan Sonja , Novkirischka Malina , Alexandrov Stojan , Petkov Plamen 
Published: September 2010

AbstractThe trace content of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in boric acid is determined by flame AAS after extraction with DDTC/MIBK. The preconcentration efficiency is enhanced by dissolution of H3BO2 in NH4P or NaOH. The method permits the determination of 3 . 10−63 . 10−7 % of the elements with good precision and accuracy. The concentration of trace Cl− in H3BO3 is estimated by spectralphotometry with Hg(SCN)2. The applicability of white‐spirit as organic solvent in the extraction flame AAS is further discussed.
Funktionalisierung von makromolekularen organischen Verbindungen zur Einführung biologisch aktiver Gruppen
Authors: Hartmann Manfred , Klemm Dieter 
Published: September 2010

AbstractMacromolecular organic compounds with biologically active groups have received increasing interest as drugs, herbicides and pesticides, disinfectants as well as technical biocides possessing novel properties. From the organic chemist's point of view, the synthesis of these modified polymers involves several attractive problems: search for suitable polymeric carriers, the design of the enzyme‐sensitive bond of the active agent and the optimum route of functionalization of synthetic or naturally occurring macromolecular materials. Of particular importance are biological and economic aspects derived from the special application, and any suggested solution must be checked in the same way.This review surveys structural concepts and selected sythetic methods which are of general importance in the attachment of biologically active agents to macromolecules.
Thiolierungsreagenzien in der organischen Chemie
Authors: Viola Horst 
Published: September 2010

AbstractVarious reagents for thiolation generally available or easily accessible are reviewed and briefly characterized. A classification of the reagents with respect to the primary step of reaction enables synthetic chemists to select an appropriate reagent to produce definite products under mild and optimized conditions. There is a wide range of reagents of graduated reactivity for electrophilic thiolation.