bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergien zwischen Bio‐ und Ölraffinerien bei der Herstellung von Biomassetreibstoffen
Authors: Huber George W. , Corma Avelino 
Published: July 2007

AbstractKontinuierlich steigende Erdölpreise werden dazu führen, dass Biotreibstoffe für unsere Energieversorgung zunehmend an Bedeutung gewinnen. Hydrotreating und katalytisches Cracken von Biomasse‐Einsatzstoffen, die aus Cellulose, Stärke und Zucker oder auch pflanzlichen Ölen erhalten werden, bieten aussichtsreiche Perspektiven für die zukünftige Produktion solcher Biotreibstoffe. Die bereits existierenden Erdölraffinerien eignen sich dabei als Infrastruktur für die Herstellung von Biotreibstoffen, sodass ein schneller Umstieg auf nachhaltigere Energiequellen ohne große Kapitalinvestitionen in neue Reaktoren vollzogen werden kann. Die chemischen Prozesse und Katalysatoren sowie die technischen Herausforderungen bei der Produktion von Biotreibstoffen werden in diesem Aufsatz diskutiert.
Kinetic study on cross‐linking and blowing behavior of EVA/EPDM/CPE high elasticity material
Authors: Liu Can‐Pei , Lin Jin‐Huo 
Published: July 2007

AbstractBlend of ethylene‐vinyl acetate copolymer (EVA), ethylene‐propylene‐diene terpolymer rubber (EPDM), and chlorinated polyethylene (CPE) filled with talc was cross‐linked with dicumyl peroxide and blown simultaneously with azodicarbonamide for preparation of high elasticity material by injecting, cross‐linking, and blowing process. It had excellent mechanical properties and elasticity. It was found that mechanical properties were a function of cross‐linking and blowing temperature and time and formula. A good cross‐linking and blowing temperature was in the range of 440–450 K and the optimum temperature and time were 448 K and 360 s, respectively. Kinetics of both cross‐linking and blowing reactions were investigated by closed nonrotor torque rheometer. The results showed that both cross‐linking and blowing reactions were first order. The activation energy of the cross‐linking reaction was higher than that of the blowing reaction. With increasing of EDPM content, the activation energy of the cross‐linking reaction reduced whereas it increased for the blowing reaction. The gas cell morphology was characterized by scanning electron microscopy (SEM). The results of SEM and mechanical property analyses showed that the morphology and mechanical properties were improved by incorporating CPE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Dynamics of controlled release of potassium nitrate from a highly swelling binary polymeric blend of alginate and carboxymethyl cellulose
Authors: Bajpai Jaya , Mishra Sushma , Bajpai A. K. 
Published: July 2007

AbstractHighly water absorbing and homogeneous binary biopolymeric blends in bead form were prepared of calcium alginate and carboxymethyl cellulose by solution cast method. The prepared blends were evaluated for controlled delivery of KNO3 taking it as a model agrochemical. The beads characterized by Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were used to investigate the molecular structure and morphology of beads. The swelling experiments were performed for different compositions of beads and at varying pH and temperature of the aqueous media. The release experiments were performed under static and varying experimental conditions and the release data obtained were conductometrically fitted to Ficks equation to evaluate diffusion coefficients of released KNO3. The release results were further analyzed by Ficks power law equation, and the possible mechanisms of KNO3 release were explored at different experimental conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Studies on the photo‐oxidation of PP and PP/mLLDPE blend systems: Thermal, physicochemical, and mechanical behavior
Authors: Gupta A. P. , Saroop U. K. , Gupta Vidya 
Published: July 2007

AbstractThe photo‐oxidative degradation of the blends of polypropylene (PP) with metallocene linear low density polyethylene (mLLDPE) were studied. The blend samples were exposed to the ultraviolet radiation (UV) for a period of 6 weeks. Tensile mechanical characteristics were derived from stress–strain curves. The changes in crystallinity during exposure were followed by X‐ray diffraction (XRD) and differential scanning calorimetry (DSC), whereas the chemical degradation of the blend samples was evaluated by FTIR‐ATR. In case of PP, tremendous decrease is observed in tensile strength, elongation at break, and increase is observed in tensile modulus with exposure time. However, with the addition of mLLDPE, UV stability of PP has significantly improved. A significant increase in crystallinity during UV exposure was noted for PP, whereas for PP/mLLDPE (80/20) blend system the crystallinity did not change much. Therefore low level of stabilizers may be required for PP/mLLDPE blend systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Cell Cycle Genes PEDF and CDKN1C in Growing Deer Antlers
Authors: Lord Eric A. , Martin Shirley K. , Gray Jason P. , Li Chunyi , Clark Dawn E. 
Published: July 2007

AbstractDeer antlers are the only mammalian appendage to display an annual cycle of full regeneration. The growth phase in antler involves the rapid proliferation of several tissues types, including epidermis, dermis, cartilage, bone, blood vessels, and nerves. Antlers thus provide an excellent model to study the developmental regulation of these tissues. We describe here the identification of two genes, pigment epithelium‐derived factor (PEDF) and cyclin‐dependent kinase inhibitor 1C (CDKN1C), both of which are known to be involved in cell proliferation and differentiation. These genes were identified as the result of screening an expressed sequence tag database derived from a cDNA library enriched for sequences from the growing antler tip. PEDF mRNA was detected in developing skin, cartilage, and bone during endochondral ossification. PEDF mRNA was not detected within endothelial cells that exhibited positive immunoreactivity to a CD146 antibody. CDKN1C mRNA was expressed by only the immature chondrocytes within the precartilage region. These results suggested that PEDF and CDKN1C are important genes involved in cell proliferation and differentiation during antler growth. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.
Long‐term stability of edible preferences in individuals with developmental disabilities
Authors: Ciccone Francis J. , Graff Richard B. , Ahearn William H. 
Published: July 2007

AbstractMultiple stimulus without replacement (MSWO) preference assessments were used to examine the stability of preference hierarchies in eight individuals with developmental disabilities. In Study 1, preference assessments using edible items were conducted 6 months apart; in Study 2, assessments were conducted 12 months apart. As in previous studies analyzing preference stability, individual differences in stability were found in both studies. However, mean rank order coefficients across participants revealed interesting findings in both comparisons. Generally, preference for edible items, particularly the most and least preferred stimuli, was more stable across time than has been found in other research conducted with leisure items. Stability was greater when only 6 months lapsed between assessments. Moreover, for three of the eight participants, rank order coefficients were significant across both studies indicating the possibility that some individuals may tend toward more stable preferences. Copyright © 2007 John Wiley & Sons, Ltd.
Development of a convenient peptide‐based assay for lysyl hydroxylase
Authors: Cudic Mare , Patel Deepak A. , Lauer‐Fields Janelle L. , Brew Keith , Fields Gregg B. 
Published: July 2007

AbstractHydroxylysine (Hyl) is a posttranslationally modified amino acid found mainly in collagens, the most abundant protein in mammals. Lysyl hydroxylase (LH) catalyzes the hydroxylation of the C‐5 position of a Lys residue, resulting in the production of Hyl. Mechanistically, LH incorporates one oxygen atom into both Lys and 2‐oxoglutarate; the latter is decarboxylated to form succinate and CO2. To develop a convenient, RP‐HPLC based LH assay, we used Fmoc solid‐phase methodology to synthesize three different peptides designed as LH substrates and one peptide corresponding to an LH product. Peptides were characterized by RP‐HPLC, MALDI‐TOF mass spectrometry and CD spectroscopy. Separation of peptides was examined under a variety of RP‐HPLC conditions. The best results were achieved using peptide derivatization (1‐anthroylnitrile for organic phase and dansyl chloride for aqueous phase) prior to RP‐HPLC analysis. The products (di‐ and tetra‐substituted Lys‐ and Hyl‐containing peptides) were well resolved by RP‐HPLC. The resolution of each peak allows for quantification of peak areas, which in turn, when examined as a function of time, can be utilized for studying the kinetics of LH catalyzed reactions. Most significantly, the RP‐HPLC assay directly monitors the Hyl containing product. Prior LH assay methods are multi‐step, require radio‐labeled substrates, and/or measure depletion of 2‐oxoglutarate or formation of CO2. Since the LH reaction with 2‐oxoglutarate is uncoupled from Lys hydroxylation, the most accurate assay of LH activity should monitor the formation of Hyl. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 330–338, 2008.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
An alternative presentation of metabolism
Authors: Waelbroeck Magali 
Published: July 2007

AbstractWhy should we think of enzymes as sluice gates? We are used to talk about “metabolic flux”: I should like to suggest that we should indeed envision metabolism as a “liquid” flowing in different channel segments, each of which contains a single metabolite. Enzymes facilitate chemical reactions without affecting the reaction equilibrium, creating, or destroying matter: they can be visualized as “sluice gates” (mobile metal or wooden plates that control water flow in channels and sluices: Fig. 1), or, rather, as openings in metal or wooden plates that block the channel. Metabolism control and homeostasis maintenance are equivalent to controlling the water flux while maintaining the water level in each channel segment approximately constant. The “gates” representing non cooperative (Michaelis‐Menten) and cooperative enzymes have very different shapes, reflecting their different roles in metabolic regulation: the activity of noncooperative enzymes catalyzing irreversible reactions has the greater effect over the flux, but cooperative enzymes are necessary to maintain homeostasis when irreversible reactions are involved.
An integrated strategy for teaching biochemistry to biotechnology specialty students
Authors: Ouyang Liming , Ou Ling , Zhang Yuanxing 
Published: July 2007

AbstractThe faculty of biochemistry established an integrated teaching strategy for biotechnology specialty students, by intermeshing the case‐study method, web‐assistant teaching, and improved lecture format with a brief content and multimedia courseware. Teaching practice showed that the integrated teaching strategy could retain the best features of each pedagogy and better solve the main difficulties that lay in the teaching of biochemistry to biotechnology specialty students in the East China University of Science and Technology.
Hydroxy‐ and Carboxy‐Substituted Allylsilanes: A Simple and Stereoselective Method of Preparation
Authors: Moret Etienne , Franzini Livia , Schlosser Manfred 
Published: July 2007

AbstractWhen treated with two equivalents of a butyllithium/potassium tert‐butoxide mixture, terminal olefins carrying unprotected hydroxy or carboxy groups generate allylmetal intermediates which can be trapped with chlorotrimethylsilane to afford functionalized (Z)‐2‐alkenyltrimethylsilanes. One equivalent of the superbasic reagent suffices if the unsaturated alcohols are first protected as acetals before being subjected to the metalation/silylation/hydrolysis sequence.
Organoamido‐ and Aryloxolanthanoids, 15. Organometallic Compounds of the Lanthanoids, 116. Syntheses of Low Coordination Number Divalent Lanthanoid Organoamide Complexes, and the X‐ray Crystal Structures of Bis[(N‐2,6‐diisopropylphenyl)(N‐trimethylsilyl)amido]bi(tetrahydrofuran)samarium(II)and ‐ytterbium(II)
Authors: Deacon Glea B. , Fallon Gary D. , Forsyth Craig M. , Schumann Herbert , Weimann Roman 
Published: July 2007

AbstractThe Mercury(II) amide complex Hg[N(SiMe3)(2,6‐iPr2C6H3)]2 (1) was prepared by reaction of HgBr2 with Li[N(SiMe3) 2,6‐iPr2C6H3)] in diethyl ether solvent. Redox transmetallation reactions of 1 with elemental samarium, europium or ytterbium in THF solvent (THF = tetrahydrofuran), generated the novel divalent complexes Ln[N(SiMe3)(2,6‐iPr2C6H3]2(THF)2 with Ln = Sm (2), Eu (3) and Yb (4). 4 was also synthesized by reaction of elemental ytterbium, HgPh2 and HN(SiMe3)(2,6‐Me3)2]2(THF)2 [Ln = Sm (5), Yb (6)] by reaction of the metals with HgPh2 and HN(SiMe3)2. Thermal desolvation of 4 under high vacuum gave Yb(N)(SiMe3)2,6‐iPr2C6H3)]2 (THF) (7), whereas under identical conditions 6 yielded the solvent‐free complex [Yb[N{SiMe3)2]2]2. (8). The new compounds 1–4 and 7 are hydrocarbon soluble and 171Yb‐NMR spectra were recorded for 4, 6, 7 and 8. X‐ray crystal structure determinations of 2 and 4 revealed four‐coordinate, distorted tetrahedral metal environments augmented by weak Ln…ipso‐C(aryl) interactions.
Unsymmetric Dinucleating Ligands for Metallobiosite Modelling
Authors: Fenton David E. , Okawa Hisashi 
Published: July 2007

AbstractAwareness of the asymmetric nature of numerous dinuclear metallobiosites and of the ability of the individual metal ions to have quite distinct roles in the functioning of the metalloenzyme concerned has led to a search for carefully designed unsymmetric dinucleating ligands that will give dinuclear complexes capable of acting as models for the metallobiosites. This review surveys progress made in the design and synthesis of complexes capable of serving as models for donor atom, coordination number and geometric asymmetries found at dinuclear metal centres.
The Electronic Structure of [Te15Br4][MoOBr4]2 and Some General Aspects of Bonding in “Classical” and Hypervalent Tellurium Halides
Authors: Landrum Gregory A. , Goldberg Norman , Hoffmann Roald 
Published: July 2007

AbstractApproximate MO and band structure calculation are used to analyze the bonding in the recently synthesized paramagnetic, semiconducting phase [Te15Br4]2+. The [Te15Br4]2+ chains are very similar to those in the tellurium subhalide Te2Br. The electronic structure and bonding within these chains is analysed and the possibility of hypervalency in both [Te15Br4][MoOBr4]2 and Te2Br is discussed. The bonding in the classically hypervalent molecule TeBr42− and a model Te3Br24‐ is compared to that of the infinite system. Our calculations indicate that both [Te15Br4][MoOBr4]2 and Te2Br contain weakly hypervalent Te atoms and that the interesting electronic properties of [Te15Br4][MoOBr4]2 arise within the distinct sublattices, which do not interact significantly.
Diazosulfonate Substitutents: A Route to Transition‐Metal Complexes with Switchable Water Solubility
Authors: Herdtweck Eberhardt , Peters Frank , Wagner Matthias 
Published: July 2007

AbstractThe single‐crystal X‐ray structure analysis of the diazosulfonatep‐H2N–C6H4–NN–SO3Na3features a Z configuration of the diazo moiety and a nitrogen–sulfur bond. Each sodium atom is coordinated by one diazosulfonate substitutent in a chelating manner. Upon reaction of3with excess salicylaldehyde, the highly water‐soluble Schiff base ligand6is obtained in good yield. Treatment of ZnCl2with 2 equiv. of6gives the zinc complex7. In all cases, the solubilizing diazosulfonate groups can be cleaved off photolytically, which offers an opportunity to precipitate the molecules from their aqueous solutions.
Synthesis and Photophysical Properties of New 2,2′‐Bipyridine‐Bridged Bis[ruthenium(II)tris‐2,2′‐bipyridine] Complexes
Authors: König Burkhard , Zieg Harald , Cola Luisa De , Balzani Vincenzo , Nimtz Manfred , Balzani Vincenzo 
Published: July 2007

AbstractWe have synthesized a new type of tris‐2,2'‐bipyridine ligand with 4,4'‐ and 6,6'‐disubstituted 2,2'‐bipyridine (bpy) units. The terminal 4,4'‐and 6,6'‐disubstituted 2,2'‐bipyridine moieties are selectively coordinated by Ru(bpy)2 (bpy = 2,2′‐bipyridine), whereas the central 2,2′‐bipyridine ligand does not participate in any metal ion coordination. The two Ru(bpy)3 units of 7 and 8 do not interact appreciably, as is evident from their electrochemical and photophysical data. The lifetime of the excited state of compound 7 at 77 K is similar to that of Ru(bpy)2(4,4′‐dimethyl‐2,2′‐bipyridine), whereas that of compound 8 under the same conditions is comparatively long.
Enantioselective Catalysis, XIVAsymmetric Grignard Cross‐Coupling Reaction: An Investigation of the Factors Influencing Asymmetric Induction with a New Type of Pyrrolidinephosphane
Authors: Nagel Ulrich , Nedden Hans GüNter 
Published: July 2007

AbstractAn investigation of the asymmetric synthesis of 3‐phenyl‐1‐butene by the Grignard cross‐coupling reaction is presented. The reaction is catalysed by nickel complexes of bisphosphane and 3‐diphenylphosphanylpyrrolidine‐type ligands. A comparison of the results obtained with our P,N monophosphane ligands with those obtained with the most effective known amino acid derived P,N ligands shows a similar enantioselectivity but an inverse sense of optical induction. An X‐ray structural analysis of the 1‐phenylethyl Grignard compound is reported. Quantitative analysis and the determination of enantiomeric composition of the catalytic samples is accomplished using a novel enantioselective GLC separation. Compared to the popular model reaction that uses a chloride‐containing Grignard compound and vinyl bromide as starting compounds, we obtain improved enantioselectivities of P,N monophosphane catalysts by substituting vinyl bromide with vinyl chloride. With two of the new P,N ligands we find a nonlinear dependence of enantioselectivity on the enantiomeric purity of the ligands (asymmetric amplification). Catalytic results subject to such nonlinear effects show a dependence on the ligand to nickel ratio.
The First Electron‐Donor‐Acceptor Paracyclophanes with Ferrocene NLO‐Phores: Synthesis, Absorption and Electrochemical Properties
Authors: Kay Kwang‐Yol , Baek Yong Gu 
Published: July 2007

AbstractAs potential nonlinear optical material. 12‐nitro‐4,7‐bis(2‐ferrocenylvinyl)[2.2]paracyclophane (1) and 12‐nitro‐4,5,7,8‐tetrakis(2‐ferrocenylvinyl)[2.2]paracyclophane(2) have been synthesized by pd‐catalyzed coupling reactions of vinylferrocene with the precursor cyclophanes 9 and 13, respectively. The absorption and electrochemical properties of 1 and 2 are also described.
Dynamic Behavior of Anionic Binuclear Helicate‐ and meso‐Helicate‐Type Coordination Compounds
Authors: Albrecht Markus , Schneider Matthias , Röttele Herbert 
Published: July 2007

AbstractThe racemization/symmetrization of helicate‐ or meso‐helicate‐type dinuclear titanium(IV) complexes Mn[(ligand)3Ti2] (n = 4: M = Li, Na, K, Cs; n = 2: M = Ca, Sr), which are formed by metal‐directed self‐assembly of alkyl‐bridged bis(catecholate) ligands in the presence of basic alkali‐metal or alkaline‐earth metal salts, can be monitored by dynamic NMR spectroscopy. The free‐energy barrier (ΔG‡) of this process is influenced by the nature of the ligand, the solvent, and the counterion.
Solid‐State 13C‐NMR‐Spectroscopy, 3. – Solid‐State 13C‐NMR‐Spectroscopic Investigations of α‐(Dimethylamino)‐benzyllithium Complexes
Authors: Ahlbrecht Hubertus , Harbach Jürgen , Kalinowski Hans‐Otto , Lang Andreas , Maier Günther 
Published: July 2007

Abstractα‐(Dimethylamino)benzyllithium (1a) and its complexes, 1b–f, have been characterized by their solid‐state 13C‐NMR spectra. The spectra are comparable to those recorded in solution and can be used to reveal the structures of the different solvates of the title compound.
Reaction of 1,3‐Dialkyl‐4,5‐dimethylimidazol‐2‐ylidenes with 2‐Bromo‐2,3‐dihydro‐1H‐1,3,2‐diazaboroles (Alkyl=iPr and tBu)
Authors: Weber Lothar , Dobbert Eckhard , Stammler Hans‐Georg , Neumann Beate , Boese Roland , Bläser Dieter 
Published: July 2007

Abstract2‐Bromo‐2,3‐dihydro‐1H‐1,3,2‐diazaboroles (3a–c) were synthesized by cyclocondensation of dilithiated 1,4‐diazabutadienes (5a–c) with boron tribromide in hexane. 3a was also obtained by sodium amalgam reduction was conducted in ether solvents, diboroxane (2) resulted as the main product. Compound 3a and 1,3‐dialkyl‐4,5‐dimethylimidazol2‐ylidenes (6a, b) underwent halide displacement to afford the borolylimidazolium salts 7a, b. Compounds 2, 3a–c, and 7a, b were characterized by elemental analyses and spectroscopic methods (1H, 11B, 13C NMR; Ir; MS). The molecular structures of 2 and 7a were established by single‐crystal X‐ray diffraction analyses.
Synthesis and Crystal Structure of tert‐Butylamino)di‐tert‐butyl)siliceniotrichloroaluminate, (Me3C)2SiNCMe3·AlCl3, and Dimethylazomethine‐Aluminium Trichloride, Me2CNH·AlCl3
Authors: Klingebiel Uwe , Noltemyer Mathias , Schmidt Hans‐Georg , Schmidt‐Bäse Dieter 
Published: July 2007

AbstractLithiated text‐butylaminolfluorosilanes react with aluminum trichloride in ether, eliminating LiF to give AlCl3 adducts of iminosilanes — aminosiliceniotrichloroaluminates {R2Si‐NCMe3·AlCl3}, which thermally form the dimethylazomethine‐ aluminium trichloride, Me2CNH·AlCl3.
Base‐Induced Synthesis of a Tetrastannatriazabicyclo[3.1.1]heptane from Tris)dimethylchlorostannyl)amine
Authors: Kober Christian , Nöth Heinrich , Storch Wolfgang 
Published: July 2007

AbstractTris(dimethylchlorostannyl)amine (2a) reacts with pyridine in a 3:4 molar ratio to produce the tin‐nitrogen containing bicyclo[3.1.1]heptane (3) with elimination of the adduct Me2SnCl2·2 py. Treatment of the distannylamine 2,6‐[Pr2H3N(SnMe2Cl)2 (4) with pyridine, however, leads to the formation of the 1:1 pyridine adduct 4 and this can be regarded as a model to explain the route to 3. The molecular structures of 3 and 5 were determined by multinuclear magnetic resonance spectroscopy in solution, as well as by X‐ray structure analysis of their crystals. Typical structural features for both compounds are intramolecular SnXSn bridges. Support for the structures comes from MS fragmentation patterns, IR spectra, and the Mössbauer spectra.
A New Lithium 5‐Methyl‐1,3‐dithia‐5‐azacyclohex‐2‐ylborate —5‐Borane and Two Dimeric 5‐Methyl‐1,3‐dithia‐5‐azacyclohex‐2‐yllithium Compounds — Stereochemistry and Reactivity
Authors: Guadarrama‐Pérez Carlos , Cadenas‐Pliego Gregorio , Martínez‐Aguilera Luz Maria R. , Flores‐Parra Angelina 
Published: July 2007

AbstractSyntheses of the dimers of axial 5‐methyl‐2‐dithiazinyllithium (4) and equatorial 5‐methyl‐2‐diethiazinyllithium‐5‐borane (5), and lithium 5‐methyl‐2‐dithiazinanylborate‐5‐borane (6) are reported. Compounds 4, 5, and 6 are configurationally and conformationally stable. The 1H‐, 13H‐, 13C‐, 11B‐, and 7Li‐NMR study of th reactions of 4 and 5 with BH3S(CH3)2, BH3—THF, and CH3I is presented.