bluuebunny/crossref_metadata_2025 huggingface dataset:
Catalysis investigation of PET depolymerization under metal oxides by microwave irradiation
Authors: Song Xiaofang , Zhang Shuzhen , Zhang Dong
Published: May 2010

Grain poly(ethylene terephthalate) (PET) was depolymerized in pure water by different metal oxides, respectively. The catalytic hydrolysis product of terephthalic acid (TPA) obtained was the same with the no catalytic reaction. The depolymerization rate of PET was seriously influenced of the reaction time and temperature. Especially using stannous oxides as catalyst, with a reaction time of 210 min, a temperature of 200°C and a pressure of 200 psi, the depolymerization rate of PET increased from 59.3 to 90.9% compared with the no catalytic reaction. The morphology of the solid residue indicated that the depolymerization took place on the external surface of the PET grain in the presence of stannous oxide. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Curing mechanisms and kinetic analysis of DGEBA cured with a novel imidazole derivative curing agent using DSC techniques
Authors: Liu Li , Li Ming
Published: May 2010

A novel imidazole derivative, 2MI‐g‐CA, was obtained through the reaction of 2‐methylimidazole (2MI) and cyanuric acid (CA) and characterized by means of elemental analysis, FTIR spectroscopy, 1H NMR spectroscopy, and mass spectrometric analysis. The curing mechanisms and kinetics of diglycidyl ether of bisphenol A (DGEBA) using 2MI and 2MI‐g‐CA as curing agents were studied with differential scanning calorimetry (DSC) under dynamic and isothermal conditions. Both dynamic and isothermal DSC thermograms of DGEBA/2MI system showed two distinct exothermic peaks, whereas those of DGEBA/2MI‐g‐CA system showed only one distinct exothermic peak. These results indicated that the two systems have different initiation curing mechanisms. The apparent activation energies (Ea) obtained from DSC scanning runs using the Kissinger and Ozawa methods were 79.0, 83.0 kJ/mol and 84.2, 88.8 kJ/mol for DGEBA/2MI and DGEBA/2MI‐g‐CA systems, respectively. These values suggested the novel curing agent 2MI‐g‐CA exhibited greater levels of latency during cure or increased the pot life of epoxy resin system. In addition, under the same curing condition, the Tg values of DGEBA/2MI‐g‐CA system were about 25°C higher than those of DGEBA/2MI system, exhibiting a better thermal stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Polyurethanes from benzene polyols synthesized from vegetable oils: Dependence of physical properties on structure
Authors: Dumont Marie‐Josée , Kong Xiaohua , Narine Suresh S.
Published: May 2010

Asymmetric and symmetric aromatic triol isomers were synthesized from erucic acid. The pure asymmetric and symmetric triols were crosslinked with MDI into their corresponding polyurethane sheets. The physico‐chemical properties of these polyurethanes were studied by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analysis coupled with Fourier transform infrared (TGA‐FTIR) spectroscopy, and tensile analysis. The A‐PU and S‐PU demonstrated differences in their glass transition temperatures (Tg) and crosslinking densities. The difference inTgof these polyurethanes could be explained by the differences in crosslinking densities, which could be related to the increase in steric hindrance, to the crosslinking MDI molecules, between adjacent hydroxyl groups of the asymmetric triol monomers. Overall, it was found that both polyurethanes had similar mechanical and thermal properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Step‐growth polymerization of 5‐[(9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboximido)‐3‐methylbutanoyl‐amino]isophthalic acid with aromatic diols
Authors: Mallakpour Shadpour , Mirkarimi Fatemeh
Published: May 2010

cis‐9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboxylic acid anhydride (1) was converted to imide acid (2) by reaction with S‐valine. Compound 2 was converted to the acid chloride (3) by reaction with thionyl chloride and then treated with 5‐aminoisophthalic acid in dry N,N‐dimethylacetamide to obtain 5‐[(9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐dicarboximido)‐3‐methylbutanoylamino]isophthalic acid (4). Direct step‐growth polymerization of this novel chiral diacid monomer 4 with a series of different diols in a system of tosyl chloride, pyridine, and N,N‐dimethylformamide was carried out. The optically active polyesters (PEs) were obtained with good yield and moderate inherent viscosity ranging from 0.23 to 0.48 dL/g. The resulting polymers were characterized with FTIR, 1H‐NMR, and elemental analysis techniques. The prepared PEs showed good thermal stability up to 320°C as measured by thermogravimetric analysis. Specific rotation experiments demonstrated the induction of optical activity due to successful insertion of S‐valine in the structure of pendant groups. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of a new acrylic polymeric ibuprofen prodrug
Authors: París Rodrigo , García José Manuel , Quijada‐Garrido Isabel
Published: May 2010

Ibuprofen‐linked 2‐hydroxypropyl acrylate, a new acrylic derivative of ibuprofen in which the drug is separated from the polymerizable double bond by two hydrolytically labile ester bonds, was directly synthesized from the reaction between 2‐hydroxypropyl acrylate and ibuprofen. This drug containing monomer was easily homopolymerized by free radical polymerization. The characterization of the resulting products by nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) indicated that the polymeric prodrugs were successfully synthesized. In addition, the flexible acrylate backbone provides the polymers low‐glass transition temperatures and in consequence good processability. Ibuprofen release from the polymer was preliminary evaluated at different pH conditions to show the capacity of these compounds to release the drug under hydrolytic conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Interaction mechanism of mono‐PEGylated proteins in electrostatic interaction chromatography
Authors: Abe Mitsuyo , Akbarzaderaleh Parvin , Hamachi Masataka , Yoshimoto Noriko , Yamamoto Shuichi
Published: May 2010

The retention and binding mechanisms in electrostatic interaction‐based chromatography (ion‐exchange chromatography) of PEGylated proteins (covalent attachment of polyethylene glycol chains to protein) were investigated using our previously developed model. Lysozyme and bovine serum albumin were chosen as model proteins. The retention volume of PEGylated proteins shifted to lower elution volumes with increasing PEG molecular weight compared with the non‐modified (native) protein retention volume. However, PEGylation did not affect the number of binding sites appreciably. The enzyme activity of PEGylated lysozyme measured with a standard insoluble substrate in suspension decreased considerably, whereas the activity with a soluble small‐molecule substrate did not drop significantly. These findings indicate that when a protein is mono‐PEG‐ylated, the binding site is not affected and the elution volume reduces due to the steric hindrance between PEGylated protein and ion‐exchange ligand.
Effective solution chemistry instruction by integrating live pC–pH diagrams into PowerPoint
Authors: Goudar Chetan T. , Nanny Mark A.
Published: May 2010

pC–pH diagrams provide a graphical illustration of chemical speciation as a function of pH and are hence a very effective tool for understanding the chemical system being studied. This understanding can lead to assumptions that simplify problem solving. However, manual construction of pC–pH diagrams for multiprotic systems is cumbersome and is further complicated by non‐standard temperature and ionic strength conditions. As a result, construction of pC–pH diagrams can become the focus of classroom teaching rather than their application to solving real‐world problems. Students tend to get lost in the complexities of pC–pH diagram construction and often fail to appreciate their value in problem solving. To address this limitation, we have developed interactive pC–pH diagrams for mono, di, and triprotic systems that are all bundled into a single PowerPoint file. The governing equilibrium equations are presented adjacent to the pC–pH diagram which makes the entire process transparent. The diagrams update in real‐time when the total concentration and pKa are changed by the user making them universally applicable to any mono, di, or triprotic system. Temperature impact on pKa and the pC–pH diagram can also be examined for some commonly encountered systems. Because of PowerPoint integration, there is no learning curve and specification of pKa is typically all that is required to use these diagrams. A real‐world application of these interactive pC–pH diagrams is presented by examining the solution chemistry in therapeutic protein‐producing mammalian cell bioreactors. The cause of high bioreactor CO2 concentration and strategies to overcome it were determined just by using the interactive pC–pH diagrams without resorting to numerical calculations. We believe these easy to use and interactive pC–pH diagrams could be more extensively used for problem solving in the classroom simultaneously enhancing student understanding of the chemical system being studied. The PowerPoint file with the pC–pH diagrams is available free of charge for academic use. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 741–749, 2012
Diet‐induced obesity in Sprague–Dawley rats causes microvascular and neural dysfunction
Authors: Davidson Eric P. , Coppey Lawrence J. , Calcutt Nigel A. , Oltman Christine L. , Yorek Mark A.
Published: May 2010

Background

The objective of this study was to determine the effect of diet‐induced obesity (DIO) on microvascular and neural function.

Methods

Rats were fed a standard or high fat diet for up to 32 weeks. The following measurements were carried out: vasodilation in epineurial arterioles using videomicroscopy, endoneurial blood flow using hydrogen clearance, nerve conduction velocity using electrical stimulation, size–frequency distribution of myelinated fibres of the sciatic nerve, intraepidermal nerve fibre density using confocal microscopy and thermal nociception using the Hargreaves method.

Results

Rats fed a high fat diet for 32 weeks developed sensory neuropathy, as indicated by slowing of sensory nerve conduction velocity and thermal hypoalgesia. Motor nerve conduction velocity and endoneurial blood flow were not impaired. Mean axonal diameter of myelinated fibres of the sciatic nerve was unchanged in high fat‐fed rats compared with that in control. Intraepidermal nerve fibre density was significantly reduced in high fat‐fed rats. Vascular relaxation to acetylcholine and calcitonin gene‐related peptide was decreased and expression of neutral endopeptidase (NEP) increased in epineurial arterioles of rats fed a high fat diet. In contrast, insulin‐mediated vascular relaxation was increased in epineurial arterioles. NEP activity was significantly increased in the skin of the hindpaw. Markers of oxidative stress were increased in the aorta and serum of high fat‐fed rats but not in epineurial arterioles.

Conclusion

Chronic obesity causes microvascular and neural dysfunction. This is associated with increased expression of NEP but not oxidative stress in epineurial arterioles. NEP degrades vasoactive peptides, which may explain the decrease in microvascular function. Copyright © 2010 John Wiley & Sons, Ltd.
Lipoxygenase and hydroperoxide lyase activities in two olive varieties from Northern Italy
Authors: Patui Sonia , Braidot Enrico , Peresson Carlo , Tubaro Franco , Mizzau Michela , Rabiei Zohreh , Conte Lanfranco , Macrì Francesco , Vianello Angelo
Published: May 2010

Lipoxygenase (LOX) and hydroperoxide lyase (HPL) activities were characterised in olive pulp microsomes from two cultivars (Ghiacciolo and Nostrana di Brisighella) from Northern Italy. LOX activity exhibited a maximum at pH 5.5 in both cultivars, and the highest value was found in cv Ghiacciolo. This was correlated with the higher total antioxidant capacity detected in cv Nostrana, rather than by a different LOX expression, as demonstrated by immunoblotting assay. Furthermore, isomer characterisation showed the predominance of 13‐hydroperoxides of linoleic acid (HPOD) in both cultivars, suggesting the occurrence of a 13‐LOX. HPL activity exhibited an optimum at pH 7.5 in the two cultivars, but was higher in cv Nostrana, as confirmed by the increased amount of hexanal production after 13‐HPOD addition. In addition, the constitutive aldehyde profile in cv Nostrana fruits were shown to be enriched in aldehydes too when compared to cv Ghiacciolo. These results suggest that the different features in the two olive cultivars are mainly due to genetic rather than environmental factors.

Practical applications: In this paper we studied the lipoxygenase (LOX) and hydroperoxide lyase (HPL) activities, and the formation of their products (hydroperoxides and aldehydes) in microsomes extracted from olive pulp of two Italian cultivars. The study of LOX and HPL, belonging to the so‐called ‘oxylipin pathway’, has important implications on the aroma development in both fruit and oil. Thus, a better knowledge of the properties of these enzymes can be useful to improve the organoleptic features of the oil. In fact, ‘LOX pathway’ may play a positive role in the formation of pleasant flavours during the technological processes. The preliminary study of the activity of the LOX/HPL enzymes could represent an important tool to facilitate the varietal choice in order to improve oil quality.
Oxidative stability of Echium plantagineum seed oil bodies
Authors: Gray David A. , Payne Gareth , McClements David Julian , Decker Eric A. , Lad Mita
Published: May 2010

Echium plantagineum seed contains a highly polyunsaturated oil (approximately 14% linoleic acid, 10% γ‐linolenic acid, 33% α‐linolenic acid and 14% stearidonic acid); almost half of the fatty acids are omega‐3 fatty acids, so there is an interest in the possible health benefits of this oil, which, once extracted, is prone to oxidation. For the first time in reported literature, oil bodies (OBs), the organelles that store the oil in mature seed, were recovered from E. plantagineum seeds. The oxidative stability of these organelles ex vivo, dispersed in an aqueous continuous phase, was tested against processed E. plantagineum oil emulsions stabilised with either SDS or Tween 20. For both primary and secondary oxidation products the OBs were the most stable form of dispersed oil, and the dispersed systems were all more stable than bulk E. plantagineum oil after incubating at 40°C for 7 days. The possible reasons for the enhanced chemical stability of E. plantagineum OBs are explored in this paper.

Practical applications: OBs, the natural store of oil in oilseeds, can be recovered from seeds intact and are relatively stable to oxidation ex vivo. Echium seed OBs, enriched in physiologically active omega‐3 fatty acids, therefore offer an attractive alternative to traditional oil extraction methods and overcome the need to encapsulate the omega‐3 rich oil.
Exploring the detection of associatively novel events using fMRI
Authors: Bubic Andreja , von Cramon D. Yves , Schubotz Ricarda I.
Published: May 2010

Identifying and evaluating events which are novel in a particular environment is crucially important for adaptive behavior. These events are often not just novel, as they typically violate expectations which may be formulated based on numerous features of our surroundings, one of which includes the ordinal structure (temporal order) of relevant stimuli. Events which violate such expectations, namely sequential deviants, constitute one category of associatively novel stimuli. The present event‐related fMRI study investigated the detection of sequential deviants presented within three types of equivalently organized, attended visual sequences which differed in stimulus dimensions relevant for defining the sequential structure (position, rhythm, and object identity). Presenting deviants within perceptual sequences defined by position and rhythm stimulus properties triggered comparable patterns of activations within the lateral parietal, premotor, and prefrontal regions. However, the activations identified in the context of position sequences showed a more dorsal distribution when compared to those in rhythm sequences. In contrast, detection of deviants within object sequences was supported by right‐lateralized parietal and temporal cortices. Thus, although the obtained results indicate similarities and partial overlap in activations triggered by specific pairs of deviants, differences in their processing were also revealed. This suggests that the general task context and specific stimulus features which define the deviant itself influence which brain regions within a widespread network incorporating lateral prefrontal, anterior premotor, and posterior (mainly lateral parietal) areas will become engaged in its processing. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.
Current Views of the Structure of the Mammalian Mitochondrial Ribosome
Authors: Koc Emine C. , Haque Md. Emdadul , Spremulli Linda L.
Published: May 2010

Mammalian mitochondria synthesize polypeptides crucial for energy generation using ribosomes with a number of unique features. These ribosomes are very protein rich and have very truncated ribosomal RNAs. The bulk of the mammalian mitochondrial ribosome is composed of proteins, only about half of which are homologs of ribosomal proteins found in other translational systems. A number of distinctive features are found in these ribosomes. Among these is a gate‐like structure that allows entrance of the primarily leaderless mRNAs that characterize this system. The exit tunnel of the large subunit is also quite unusual and includes a site in which the nascent peptide is visible to solvent prior to the normal exit site. Further, this region of the mitochondrial ribosome is dominated by ribosomal proteins rather than rRNA and is involved in the interaction of the ribosome with the inner membrane where all of the translation products are ultimately located. The proteins of the mitochondrial ribosome appear to play a number of important roles in the cell in addition to their function in protein biosynthesis, including roles in apoptosis and in cell cycle control.
Diastereoselective synthesis of nicotine derivatives via 1,3‐dipolar cycloaddition reactions
Authors: Ghandi Mehdi , Taheri Abuzar , Abbasi Alireza
Published: May 2010

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A simple diastereoselective route to nicotine derivatives is presented. The one‐pot three component 1,3‐dipolar cycloaddition reaction of the Knöevenagel adducts of a number of aromatic aldehydes and malononitrile with an azomethine ylide derived in situ from pyridine‐3‐carbaldehyde and sarcosine give access to nicotine derivatives in good yields. J. Heterocyclic Chem., (2010).
A highly efficient methodology for 5‐methyl‐3‐aryl‐2‐thiooxazolidin‐4‐ones using lithium perchlorate in DIPEA mediated synthesis
Authors: Khatik Gopal L. , Pal Anang , Apsunde Tushar D. , Nair Vipin A.
Published: May 2010

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An efficient methodology for the synthesis of 5‐methyl‐3‐aryl‐2‐thiooxazolidin‐4‐ones from aryl isothiocyanates has been developed. Aryl isothiocyanates, synthesized from various anilines, were converted to the desired compounds by treating with ethyl lactate in presence of DIPEA and catalytic amount of lithium perchlorate. This method provides a convenient and cost‐effective strategy, with no specific purification protocol. J. Heterocyclic Chem., (2010).
Thieno[2,3‐d]pyrimidines and ‐[1,3]oxazines as glutamate antagonists and investigations on the inhibitory potency toward human leukocyte elastase
Authors: Briel Detlef , Rybak Anastasiya , Kronbach Christiane , Unverferth Klaus , González Tanarro Camino M. , Gütschow Michael
Published: May 2010

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A series of fused thiophene derivatives, that is, representatives of thieno[2,3‐d]pyrimidines, thieno[2,3‐d][1, 3]oxazines and thieno[2,3‐d][1, 3]thiazines, with the common 5‐methyl‐6‐phenyl substitution pattern was synthesized. The target compounds, e.g., 7 or 8, were designed as cyclic analogs of ethyl 2‐amino‐4‐methyl‐5‐phenylthiophene‐3‐carboxylate, an antagonist at the GluR6 kainate receptor. Thieno[2,3‐d][1, 3]oxazin‐4‐one 2 (R = C2H5) was identified as new a potent inhibitor (IC50 = 17 μM) of this receptor subtype. The inhibitory potency of 2 (R = C2H5) against human leukocyte elastase was also examined. The compound was characterized as a noncovalent inhibitor with an IC50 value of 8.8 μM. J. Heterocyclic Chem., (2010).
Environmentally Friendly Copolyesters Containing 1,4‐Cyclohexane Dicarboxylate Units, 1‐Relationships Between Chemical Structure and Thermal Properties
Authors: Berti Corrado , Celli Annamaria , Marchese Paola , Marianucci Elisabetta , Sullalti Simone , Barbiroli Giancarlo
Published: May 2010

Novel aliphatic, random copolyesters, containing co‐units derived from a poly(alkylene dicarboxylate) and a poly(butylene 1,4‐cyclohexanedicarboxylate), have been synthesized and characterized in terms of molecular structure and thermal properties. In particular, the effects of the molar composition, the length of the aliphatic sequences, and the cis/trans ratio of the 1,4‐cyclohexylene units on the characteristics of the crystalline and amorphous phases are discussed. Some interesting structure‐property relationships have been found. The materials result to be very promising new biopolymers as they are characterized by a potential biodegradability and good physical properties, which can be easily modified, according to the requests of specific applications, by little changes in the molecular structure.

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Dietary arachidonic acid‐mediated effects on colon inflammation using transcriptome analysis
Authors: Knoch Bianca , Barnett Matthew P. G. , McNabb Warren C. , Zhu Shuotun , Park Zaneta A. , Khan Anar , Roy Nicole C.
Published: May 2010

Increased levels of n‐6 arachidonic acid (AA), a precursor of pro‐inflammatory eicosanoids, have been found in the colon mucosa of inflammatory bowel disease patients when compared with healthy subjects. The hypothesis was that dietary AA would aggravate colon inflammation by changing expression of genes in inflammatory signaling pathways. AA‐enriched diet was fed to IL10 gene‐deficient (Il10−/−) mice, model of a inflammatory bowel disease, and compared withIl10−/−mice fed an oleic acid control diet. Effects of AA on gene expression profiles during colitis were examined using whole genome microarray analysis. Dietary AA decreased the expression levels of some colonic genes in ER stress, complement system, nuclear respiratory factor 2‐mediated oxidative stress and positive acute phase response pathways compared withIl10−/−mice fed an oleic acid diet. AA increased the expression levels of fatty acid catabolism genes, but decreased that of lipid synthesis genes during colitis, likely by sterol regulatory element binding transcription factor 1 and target gene regulation. A link has been suggested between AA and reduction of intestinal fibrosis by down‐regulating the expression levels of pro‐inflammatory and fibrotic marker genes. Contrary to the hypothesis, these findings suggest that dietary AA, in the present experimental conditions, is not pro‐inflammatory, reduces ER stress and protects colonocytes from oxidative stress inIl10−/−mice.
2. Sommerschule „Medizinische Chemie”︁
Authors: Dove Stefan
Published: May 2010

Zum zweiten Mal hat die Fakultät für Chemie und Pharmazie der Universität Regensburg Anfang Oktober 2004 eine internationale Sommerschule „Medizinische Chemie”︁ veranstaltet. An der Organisation waren wiederum das International Quality Network Medicinal Chemistry und das Graduiertenkolleg Medizinische Chemie beteiligt. Neben der Universitätsstiftung Hans Vielberth unterstützten auch Boehringer Ingelheim, Novartis, Sanof‐Synthelabo (Aventis), Schering und Tripos. Mit mehr als 240 Studenten, Doktoranden sowie Postdocs aus Hochschulen und aus der pharmazeutischen Industrie, davon nahezu 50 aus dem Ausland, konnte die Teilnehmerzahl gegenüber 2002 nahezu verdoppelt werden. Die wissenschaftliche Diskussion beförderten 94 Poster (2002: 63).
Für die Zukunft der Juniorprofessur
Authors: Frormann Lars , Huhn Petra
Published: May 2010

Auf dem 2. Symposium Juniorprofessur in Berlin trafen sich Nachwuchswissenschaftler mit Vertretern aus Politik und Wissenschaftsverwaltung.
Wie aus „Bio”︁ Chemie wird
Authors: Busch Rainer , Deutschland Dow , Hirth Thomas , Kamm Birgit , Kamm Michael , Thoen Johan
Published: May 2010

Die Nutzung nachwachsender Rohstoffe wird die Volkswirtschaften in den nächsten Jahren verändern. Gewinnen werden nur die Wirtschaftsräume, die rechtzeitig die Entwicklung von biobasierten industriellen Produkten und Bioraffinerien fördern. Während in den USA Chemie, Biotechnologie und Landwirtschaft vielerorts schon Hand in Hand gehen, fällt in Deutschland das Umdenken noch schwer.
Kohlenstoff ans Steuer
Authors: Hintermann L.
Published: May 2010

Auf P, O und N folgt C: Können Metallkomplexe chiraler Olefine, also neutraler Kohlenstoffdonoren, wirklich als Katalysatoren in enantioselektiven Hydrierungen dienen?
Klein aber fein: der 18. CIC‐Workshop
Authors: Engel Thomas
Published: May 2010

Zum alljährlichen Workshop und intensivem wissenschaftlichen Austausch traf sich die GDCh‐Fachgruppe „Chemie, Information und Computer”︁ (CIC) Mitte November 2004 in Boppard.
Workshop: Advances in Molecular Catalysis
Authors: Kunz Doris
Published: May 2010

Im Herbst 2004 fand in Lauterbad im Schwarzwald Zum ersten Mal ein gemeinsames Seminar von vier Sonderforschungsbereichen (SFBs) mit dem Themenschwerpunkt „Molekulare Katalyse”︁ statt. Der Einladung des Heidelberger SFB 623 „Molekulare Katalysatoren: Struktur und Funktionsdesign”︁ waren 60 Teilnehmer aus den SFBs und Zwei Gastreferenten gefolgt.
Leichtflüchtige Stoffe festhalten
Authors: Kohl Rüdiger
Published: May 2010

Für die Probenvorbereitung bei der Analytik leichtflüchtiger Komponenten in Trinkwasser bieten sich zwei Methoden an: die statische Headspace und die Purge‐and‐Trap‐Technik.‐Ein Leistungsvergleich anhand einiger Parameter der Trinkwasser‐Verordnung.
Chemiedidaktik 2004
Authors: Becker Hans‐Jürgen , Eilks Ingo , Sumfleth Elke
Published: May 2010

Chemiedidaktische Forschungstrends sind ein sensibler Gradmesser für vielschichtige Problemlagen der chemischen Bildung. Chemiedidaktik bringt sich in bildungspolitische Aktivitäten ein. Internationaler Erfahrungsaustausch über Forschungsinhalte und Forschungsmethoden findet ungeachtet aller nationalen Besonderheiten statt. Er ist ‐ endlich ‐ auf die Professionalisierung von Lehrerverhalten ausgerichtet.
Nanoindentation — Härte auf mikroskopischer Skala
Authors: Drechsler Doris , Karbach Alexander
Published: May 2010

Die Härtemessung ermittelt mechanische Werkstoffeigenschaften. Inzwischen lassen sich diese Eigenschaften auf der Nanometerskala detektieren.
Start‐ups‐Innovationen im Feinen
Authors: Hauthal Hermann G.
Published: May 2010

Ausgründungen aus Universitäten und Großchemie, kleine und mittelständische Unternehmen im Umfeld großer Chemiestandorte sowie Start‐ups in Industrieparks zeigen, auf welch unterschiedlichen Wegen heute Firmen mit innovativen Produkten entstehen. Individuelle Konzepte auch bei der Finanzierung und der Gesellschaftsform erleichtern die Neugründung und das Überleben.
Treibhaus der Radikalenfänger
Authors: Blume Rüdiger
Published: May 2010

Schwach angefangen haben die chemiedokumentarisch relevanten Bemühungen der deutschen Zeitschriften‐ und Zeitungsautoren im vergangenen Jahr, dafür hat aber das Niveau rasch stark nachgelassen. Einige Themen wie Kohlendioxid aus Erdöl und fürs Treibhaus entpuppen sich als Dauer(b)renner.
Kontrolle und Sicherheit
Authors: Papke Günter , Pohl Barbara
Published: May 2010

Aus Sicht einer Landesbehörde dient die Qualitätssicherung in der Analytik dazu, die Analysenverfahren zu kontrollieren und die Ergebnisse abzusichern. Das ist gerade dann wichtig, wenn der Staat mehr und mehr eigene Laborkapazitäten abbaut und Analytikaufträge an Dienstleister vergibt.
Altbekanntes Trennprinzip ‐ neue Möglichkeiten
Authors: Köhler Nils , Winterhalter Peter
Published: May 2010

Die klassische Verteilungschromatographie erlebt als Countercurrent Chromatography (CCC) eine Renaissance in der Naturstoff‐ und Lebensmittelanalytik.
Magere Analytik für Fette und Öle
Authors: Gertz Christian
Published: May 2010

Die Technik bei der Gewinnung und Verarbeitung von Fetten und Ölen hat sich in den letzten Jahren rasant entwickelt. Die Analytik, wie sie Untersuchungsämter und Handelslabore betreiben, und auch die lebensmittelrechtlichen Beurteilungsgrundlagen haben mit dieser Entwicklung nicht Schritt gehalten.
Service für Bewerber und Arbeitgeber
Authors: Schmitz Karin
Published: May 2010

In die GDCh‐Bewerberdatenbank können sich Berufseinsteiger und Berufserfahrene kostenlos eintragen. Alle Daten werden vertraulich behandelt und Sperrvermerke beachtet. Die Datenbank ist auch für Nichtmitglieder offen.
Europa braucht mehr Wissenschaftler
Authors: Parchmann Ilka
Published: May 2010

Europa soll Standort exzellenter Wissenschaft und Forschung sein ‐ dafür brauchen die Länder nach einer Studie im Auftrag der EU‐Kommission mindestens eine halbe Million Wissenschaftler zusätzlich. Ohne umfassende und qualifizierte Nachwuchsförderung ist dieses Ziel nicht zu erreichen.
Ein Wasserstoff‐produzierendes Mitochondrium?
Authors: Groß Michael
Published: May 2010

Mitochondrien und Chloroplasten in Zellen stammen von ehemals unabhängigen Mikroben ab. Jetzt hat sich das Hydrogenosom, eine weitere Organelle, als naher Verwandter der Mitochondrien entpuppt.
Spezialchemie und Pharma legen zu
Authors: Hauthal Hermann G.
Published: May 2010

Viele Pharmaunternehmen erzielten im vergangenen Jahr Rekordgewinne und setzen auf noch mehr Forschung. Biopharmazeutika kamen voran, die Spezialchemie fokussierte immer stärker auf innovationsgetriebenen Kundenservice.
Jungchemiker international
Authors: Schaffer Tanja
Published: May 2010

Unter dem Motto „Dream. Explore. Discover.”︁ trafen sich über 200 junge Chemiker aus Europa, Nordamerika und Asien auf dem Campus Adlershof der Humboldt‐Universität zu Berlin.
Spurenanalytik mit Röntgenfluoreszenz
Authors: Janßen Anton , Flock Jörg
Published: May 2010

Die Nachweisgrenzen der wellenlängendispersive Röntgenfluoreszenz‐Spektrometrie liegen für die Spurenanalytik erst einmal zu hoch. Anreicherungsverfahren können die Nachweisgrenzen senken und machen somit diese kostengünstige Methode für spurenanalytische Aufgaben einsetzbar.
Zum Forschen nach China
Authors: Kruppa Michael , Ritter Stefan
Published: May 2010

Michael Kruppa und Stefan Ritter haben während ihrer Doktorarbeit zwei Monate am Shanghai Institut of Organic Chemistry in China gearbeitet.
Titelbild
Authors: Zahn Dirk
Published: May 2010

Kugel‐Stab‐Modell einer möglichen Vorstufe der Kristallisation von Kochsalz in Wasser [zu S.751]
Pflanzenschutz zwischen Nutzen und Risiko
Authors: Hübenthal Anke
Published: May 2010

Die Entwicklung neuer chemischer Pflanzenschutzmittel ist teuer und langwierig: Weltweit investieren noch sechs Unternehmen in die Suchforschung; jährlich kommen nur fünf bis zehn neue Wirkstoffe auf den Markt. Bei der Prüfung ihres Risikopotentials müssen Politik, Umwelt‐ und Industrieverbände Kompromisse finden, denn Bio‐ und Gentechnologie können die Agrarchemie nicht ersetzen.
Fluor, Element für (fast) alle Fälle
Authors: Röschenthaler Gerd‐Volker
Published: May 2010

Weithin in den Lehrbüchern ignoriert, ist die organische Fluorchemie eine Goldgrube für interessante Strukturen und ungewöhnliche Umlagerungen. Fluor kann im Prinzip jedes Wasserstoffatom ersetzen und damit die Eigenschaften der Ausgangsverbindungen drastisch verändern. Fluorhaltige Substanzen finden u. a. Anwendung als Medikamente, Pestizide, als Flüssigkristalle in Displays oder als ionische Flüssigkeiten.
„Ein wenig blauäugig muss man schon sein”︁
Authors: Zbikowski Fz
Published: May 2010

Beim dem Würzburger Pharma‐Start‐up Vasopharm Biotech wurde ein Forscher zum Unternehmer, und ein Kaufmann entdeckte seine Begeisterung für die Biomedizin.
Chinas chemische Industrie
Authors: Festel Gunter , Müller Heinz
Published: May 2010

Zehn Prozent des chinesischen Bruttoinlandsproduktes verantwortet inzwischen die chemische Industrie. Das Land ist damit bei Steigerungsraten um neun Prozent nach den USA und Japan der drittgrößte Markt für chemische Produkte.
Vortragstagung der Fachgruppe Photochemie
Authors: Griesbeck Axel G.
Published: May 2010

Ende März trafen sich die Mitglieder der Fachgruppe Photochemie der GDCh in Jena zur 19. Vortragstagung. Sechs Plenarvorträge ‐ je zur Hälfte im Hauptteil und einem Sonderforum ‐, 23 Kurzvorträge und 66 Poster informierten die Teilnehmer über aktuelle Aspekte der Photochemie; Ulrich‐Walter Grummt und Eckhard Birckner vom Physikalischen Institut der Universität Jena hatten vorbildlich organisiert.
Workshop „New Approaches in Drug Design and Discovery”︁
Authors: Jahnke Wolfgang
Published: May 2010

Auf Einladung von Gerhard Klebe und Christoph Sotriffer von der Universität Marburg versammelten sich Ende März knapp 100 Forscher aus aller Welt, zu etwa gleichen Teilen aus akademischem und Industriellem Umfeld (sowohl Pharma als auch Biotech), im Schloss Rauischholzhausen bei Marburg. 24 Vorträge und 20 Poster befassten sich mit Ideen und Ansätzen zur Fragment‐basierten Wirkstofffindung sowie zu computer‐gestützten Methoden zur Analyse von Bindungstaschen und Protein‐Ligand‐Wechselwirkungen.
Frontiers in Medicinal Chemistry 2005
Authors: Beck‐Sickinger Annette G.
Published: May 2010

Über 150 Teilnehmer aus Industrie und Hochschule zählte die diesjährige, gemeinsam von den Fachgruppen Medizinische Chemie der GDCh und Pharmazeutische Chemie der DPhG veranstaltete Tagung „Frontiers in Medicinal Chemistry”︁ Mitte Ma¨︁rz in der BioCity in Leipzig. Auf dem Programm standen neben Keynote‐Lectures und 22 Plenarvorträgen die Präsentation aktueller Daten in acht Kurzvortägen und über 50 Posterbeiträgen. Die Plenarvortäge hatten drei an Therapiefeldern orientierten Themenschwerpunkte: Tumorforschung, Metabolisches Syndrom und Zentralnervensystem. Eine weitere Sitzung war Highlights aus der Medizinalchemie und angrenzenden Forschungsfeldern gewidmet.
BioPerspectives 2005
Authors: Schürrle Karsten
Published: May 2010

Mitte Mai trafen sich in Wiesbaden rund 1000 Fachleute zur BioPerspectives 2005, einer gemeinsamen Biotechnologie‐Veranstaltung von 16 Organisationen. Erstmals war neben der Dechema‐Jahrestagung auch die Jahrestagung der Deutschen Gesellschaft für Proteomforschung Teil des Kongresses.
Modellierung von Wirk‐ und Werkstoffen
Authors: Horn Anselm
Published: May 2010

Zum 19. Mal fand dieses Jahr der „Darmstädter Molecular Modelling Workshop”︁ an den beiden Tagen vor Christi Himmelfahrt statt, zum dritten Mal davon in Erlangen. Ziel dieser Tagung ist es, dem wissenschaftlichen Nachwuchs, insbesondere Diplomanden und Doktoranden, die Möglichkeit zur Präsentation ihrer Ergebnisse aus laufenden Projekten zu geben.
Bürgenstock 2005
Authors: Ackermann Lutz
Published: May 2010

Die 40. Euchem Conference on Stereochemistry fand Mitte April auf dem Bürgenstock in der Schweiz statt. Präsident Alain Krief (Université de Namur) hatte ein abwechslungsreiches Programm zusammengestellt, tatkräftig unterstützt durch das Organisationskomitee, Hans‐Beat Bürgi (Universität Bern), François Diederich (ETH Zürich), E. Peter Kündig (Unversité de Genève) und Klaus Müller (F. Hoffmann‐La Roche). Das Spektrum der Vorträge reichte von den Biowissenschaften über die organische Chemie bis hin zu den Materialwissenschaften.
Analytik als Ware
Authors: Kreiss Wolfgang
Published: May 2010

Die Analytik unterliegt dem wachsenden Trend zum Outsourcing. In Deutschland steht der Nachfrage von Industrie, Verbänden und öffentlichen Institutionen ein breites Angebot an Dienstleistern gegenüber.
Bachelor und Master für Chemielehrer
Authors: Demuth Reinhard
Published: May 2010

Die universitäre Lehrerausbildung in den Naturwissenschaften ist selten optimal ‐ daher ist es grundsätzlich zu begrüßen, wenn im Zuge der Studienreform über ein neues Modell für das Lehramtsstudium nachgedacht wird. Dieses sollte unter anderem die Phasen der Lehrerausbildung verknüpfen und Entwicklungen im Bildungssystem berücksichtigen.
Antimon ‐ ein globaler Schadstoff
Authors: Krachler Michael
Published: May 2010

Untersuchungen an Torfbohrkernen aus Hochmooren in Europa belegen: Unsere Umwelt ist mit anthropogenem Antimon kontaminiert. Eisbohrkerne aus der kanadischen Arktis zeigen, dass heute doppelt so viel Antimon angereichert wird wie vor 30 Jahren. Die Atmosphäre ist in einem solchen Ausmaß mit Antimon kontaminiert, dass das Halbmetall in seiner globalen Relevanz als Schadstoff der von Blei ähnelt.
Die Deutsche Biotech‐Industrie zeigt wieder Perspektive
Authors: Bengs Holger
Published: May 2010

Die deutsche Landschaft junger Biotech‐Unternehmen hält länger durch als manche Branchenauguren noch vor zwei Jahren prophezeiten. Die jüngsten Zahlen von Ernst & Young wecken zwar keine Euphorie, weisen aber begründet in eine solide Zukunft.
Aktuelle Nachrichten frei Haus: RSS‐Feeds
Authors: Horn Anselm
Published: May 2010

Inzwischen ist es möglich, per Internet weltweit und tagesaktuell Informationen zu allen erdenklichen Themen zu recherchieren. Die Kunst dabei besteht inzwischen darin, gezielt und schnell relevante und interessante Beiträge aus der Informationsflut herauszufiltern. Neben Suchmaschinen und Newslettern bieten RSS‐Feeds hierfür eine Lösung.
Flüssigkeiten als Reaktandgas in der Chemischen Ionisation
Authors: Kaese Peter , Bruchmann Andreas , Kohl Rüdiger
Published: May 2010

In der Massenspektrometrie lassen sich bei der Chemischen Ionisation anstelle von Methan oder Ammoniak auch Flüssigkeiten mit entsprechendem Dampfdruck als Reaktandgase einsetzen, Erstmals liegen nun auch für die Negative Chemische Ionisation Ergebnisse aus Versuchen mit Wasser und Methanol vor.
Aus dem Labor ins Pharma‐Marketing
Authors: Röleke Dietmar
Published: May 2010

Produktmanager machen aus wissenschaftlichen Daten eine Verkaufsstrategie.
Langeitsicherheit der Endlagerung: aquatische Chemie der Actiniden
Authors: Klenze Reinhardt , Fanghänel Thomas
Published: May 2010

Die Mobilität von Actiniden in aquatischen Systemen lässt sich auf der Basis von Prozessverständnis und fundierten thermondynamischem Daten wesentlich zuverlässiger beschreiben als bislang mit rein phänomenologischen Ansätzen. Berücksichtigt man das geochemische Verhalten der Actiniden, werden belastbare Prognosen zur Langzeitsicherheit der Endlagerung nuklearer Abfälle in einer tiefen geologischen Formation möglich.
Auxin: Neues von einem alten Pflanzenhormon
Authors: Groß Michael
Published: May 2010

Hin zu Licht und Schwerkraft ‐ wie Pflanzen wachsen, ist biologisches Grundlagenwissen. Nun mehren sich endlich auch die Erkenntnisse, wie das Wachstumshormon Auxin seine Wirkung auf molekularer Ebene entfaltet.
Wirkstoffsuche auf dem Chip
Authors: Schleidt Silvia
Published: May 2010

Labore schrumpfen ‐ nicht nur in der Industrie. Das Forschungsinstitut für Molekulare Pharmakologie in Berlin ist weltweit die erste akademische Einrichtung, die mit handtellergroßen Quarz‐Chips auf Medikamentensuche geht.
Mikrowellenaufschlüsse steuern
Authors: Gutwerk Dieter , Krämer Rainer
Published: May 2010

Über berührungslose Druck‐ und Temperaturmessung lässt sich die Leistung von Mikrowellenaufsschlusssystemen regeln.
Südkorea ‐ zwischen Tradition und Aufbruch
Authors: Hilbrandt Nicole , Kruwinnus Ina
Published: May 2010

In Korea haben Wissenschaft und Bildung einen hohen Stellenwert. Dies zeigt sich darin, dass der Staat die Naturwissenschaften massiv fördert. Auch die chemische Forschung hat inzwischen ein hohes Niveau erreicht.
Mit LC/Elektrochemie/MS unpolare Substanzen analysieren
Authors: Vogel Martin , Leeuwe Suze Van , Seiwert Bettina , Karst Uwe
Published: May 2010

Elektrochemie erweitert das Einsatzgebiet der LC/MS auch auf unpolare oder nur schwer ionisierbare Verbindungen. Eine coulometrische Zelle zwischen Trennsäule und MS eignet sich sowohl zur Nachsäulenderivatisierung als auch zur Untersuchung von Redoxprozessen.
Evaluation of the usefulness of the fetal femur length with respect to gestational age to detect Down syndrome in Korean subjects
Authors: Cho H. J. , Won H. S. , Ju D. H. , Roh H. J. , Lee P. R. , Kim A.
Published: May 2010

Objective

We investigated the usefulness of shortening of the fetal femur length (FL) to predict Down syndrome at different gestational ages in Korean subjects.

Methods

This study involved 110 Korean Down syndrome fetuses and 602 randomly selected euploid controls. The expected FL for any biparietal diameter (BPD) was calculated based on the control group data. Subjects were divided into four groups according to gestational age periods: 14–18 weeks; 19–23 weeks; 24–28 weeks and 29–36 weeks. The value of measured/expected FL ratio to predict Down syndrome was analyzed for each group.

Results

The values of FL for any BPD in Down syndrome patients were significantly different from those in the control group (p < 0.001). A low ratio of measured/expected FL increased the risk of fetal Down syndrome (p < 0.001) with a mean measured/expected FL in Down syndrome of 0.907 (SD 0.075). At a fixed false positive rate of 5%, the sensitivities of FL were lower than 32.8% (95% CI 0.705–0.915) in three second trimester groups, and 71.1% (95% CI 0.924–0.997) in the third trimester group.

Conclusion

Short FL is a poor marker of Down syndrome in the second trimester in Korean subject. It may be used as a screening marker only in the third trimester. Copyright © 2010 John Wiley & Sons, Ltd.
Minimally invasive fetal postmortem examination using magnetic resonance imaging and computerised tomography: current evidence and practical issues
Authors: Thayyil S. , Chitty L. S. , Robertson N. J. , Taylor A. M. , Sebire N. J.
Published: May 2010

For a variety of reasons, acceptance of traditional postmortem examination following foetal or neonatal death has declined significantly in recent years in the UK. Here, we review the case for the development of less invasive autopsy using combined investigations including imaging techniques, in particular, magnetic resonance imaging and computerised tomography. Copyright © 2010 John Wiley & Sons, Ltd.
Dimerization of the hepatitis C virus nonstructural protein 4B depends on the integrity of an aminoterminal basic leucine zipper
Authors: Welker Martin‐Walter , Welsch Christoph , Meyer Aline , Antes Iris , Albrecht Mario , Forestier Nicole , Kronenberger Bernd , Lengauer Thomas , Piiper Albrecht , Zeuzem Stefan , Sarrazin Christoph
Published: May 2010

The hepatitis C virus (HCV) nonstructural (NS) protein 4B is known for protein–protein interactions with virus and host cell factors. Only little is known about the corresponding protein binding sites and underlying molecular mechanisms. Recently, we have predicted a putative basic leucine zipper (bZIP) motif within the aminoterminal part of NS4B. The aim of this study was to investigate the importance of this NS4B bZIP motif for specific protein–protein interactions. We applied in silico approaches for 3D‐structure modeling of NS4B‐homodimerization via the bZIP motif and identified crucial amino acid positions by multiple sequence analysis. The selected sites were used for site‐directed mutagenesis within the NS4B bZIP motif and subsequent co‐immunoprecipitation of wild‐type and mutant NS4B molecules. Respective interaction energies were calculated for wild‐type and mutant structural models. NS4B‐homodimerization with a gradual alleviation of dimer interaction from wild‐type towards the mutant‐dimers was observed. The putative bZIP motif was confirmed by a co‐immunoprecipitation assay and western blot analysis. NS4B‐NS4B interaction depends on the integrity of the bZIP hydrophobic core and can be abolished due to changes of crucial residues within NS4B. In conclusion, our data indicate NS4B‐homodimerization and that this interaction is facilitated by the aminoterminal part containing a bZIP motif.
Impact of calcium on N1 influenza neuraminidase dynamics and binding free energy
Authors: Lawrenz Morgan , Wereszczynski Jeff , Amaro Rommie , Walker Ross , Roitberg Adrian , McCammon J. Andrew
Published: May 2010

The highly pathogenic influenza strains H5N1 and H1N1 are currently treated with inhibitors of the viral surface protein neuraminidase (N1). Crystal structures of N1 indicate a conserved, high affinity calcium binding site located near the active site. The specific role of this calcium in the enzyme mechanism is unknown, though it has been shown to be important for enzymatic activity and thermostability. We report molecular dynamics (MD) simulations of calcium‐bound and calcium‐free N1 complexes with the inhibitor oseltamivir (marketed as the drug Tamiflu), independently using both the AMBER FF99SB and GROMOS96 force fields, to give structural insight into calcium stabilization of key framework residues. Y347, which demonstrates similar sampling patterns in the simulations of both force fields, is implicated as an important N1 residue that can “clamp” the ligand into a favorable binding pose. Free energy perturbation and thermodynamic integration calculations, using two different force fields, support the importance of Y347 and indicate a +3 to +5 kcal/mol change in the binding free energy of oseltamivir in the absence of calcium. With the important role of structure‐based drug design for neuraminidase inhibitors and the growing literature on emerging strains and subtypes, inclusion of this calcium for active site stability is particularly crucial for computational efforts such as homology modeling, virtual screening, and free energy methods. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Thermal behavior analysis of GaN based epi‐material on different substrates by means of a physical–thermal model
Authors: Tang Xiao , Rousseau Michel , Defrance Nicolas , Hoel Virginie , Soltani Ali , Langer Robert , De Jaeger Jean‐Claude
Published: May 2010

For gallium nitride (GaN) based microwave power devices, the thermal behavior due to the self‐heating effect constitutes a main limitation because the power dissipation is very high. For this study, a predictive physical–thermal model has been developed to analyze the physical and thermal phenomena observed in experiment.

In this paper, the thermal performances of AlGaN/GaN epitaxies grown on different substrates are determined. It is found that compared with Si substrate, composite substrates: SopSiC (mono‐Si/poly‐SiC) and SiCopSiC (mono‐SiC/poly‐SiC) substrates (V. Hoel et al., Electron. Lett. 44, 238 (2008) 1 and T.J. Anderson et al., J. Vac. Sci. Technol. B 24, 2302 (2006) 2) present better thermal resistances especially at high dissipated power densities with an improvement of 18% for SopSiC substrate and 25% for SiCopSiC substrate at 12 W/mm. Furthermore, polycrystalline diamond is the most promising substrate with a thermal resistance of 5.4 W/m·K at 12 W/mm. The simulation results, such as lattice temperature and thermal resistance, are in good agreement with our measurements.