bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioselective reduction of pentoxifylline to lisofylline using whole‐cell Lactobacillus kefiri biotransformation
Authors: Pękala; Elżbieta , Godawska‐Matysik Anna , Żelaszczyk Dorota 
Published: February 2007

AbstractLisofylline (LSF) is a drug candidate that has been under investigation for acute respiratory distress syndrome, acute lung injury, septic shock and mucositis. As LSF is not commercially available in our country, we produced it for pharmacokinetic studies. In the present work whole‐cell reduction of pentoxifylline [1‐(5‐oxohexyl)‐3,5‐dimethylxanthine] to LSF [1‐(5R‐hydroxyhexyl)‐3,5‐dimethylxanthine] using Lactobacillus kefiri DSM 20587 was investigated. Glucose or 2‐propanol was used as a co‐substrate to regenerate the NADPH cofactor. The reaction conditions were optimized. The influence of different concentrations of co‐substrates on the yield and enantioselectivity of the biotransformation of pentoxifylline into LSF were tested. Maximum yield (100%) of biotransformation was reached in the presence of glucose as a co‐substrate. At glucose concentrations of 675 and 900 mM the bioreduction of pentoxifylline proceeded highly enantioselectively (enantiomeric excess for the R enantiomer of 98%).
Genetic engineering, expression, and activity of a fusion protein of a human neurotrophin and a molecular Trojan horse for delivery across the human blood–brain barrier
Authors: Boado Ruben J. , Zhang Yufeng , Zhang Yun , Pardridge William M. 
Published: February 2007

AbstractNeurotrophins, such as brain derived neurotrophic factor (BDNF), do not cross the blood–brain barrier (BBB). Certain monoclonal antibodies (MAb) to the human insulin receptor (HIR) do cross the BBB via receptor‐mediated transport, and can act as a molecular Trojan horse to ferry across the BBB an attached drug. A genetically engineered fusion protein was produced whereby the amino terminus of human BDNF is fused to the carboxyl terminus of the heavy chain of a chimeric HIRMAb. The HIRMAb‐BDNF fusion protein reacted equally with antibodies to human IgG and BDNF. The bi‐functionality of the fusion protein was retained as the affinity of the fusion protein for the HIR was identical to that of the chimeric HIRMAb, and the affinity of the fusion protein for the trkB receptor was identical to that of BDNF. The fusion protein was equi‐potent with BDNF in a neuroprotection assay in human neural cells. The pharmacokinetics (PK) of the fusion protein was examined in the adult Rhesus monkey. The mean residence time (MRT) of the fusion protein in blood was >100‐fold longer than the MRT of BDNF. Therapeutic levels of BDNF were produced in primate brain following the intravenous administration of the fusion protein. A fusion protein tandem vector was engineered that allowed for isolation of a CHO cell line that produced the fusion protein at high levels in serum free medium. Neurotrophins, such as BDNF, can be re‐formulated to enable these molecules to cross the human BBB, and such fusion proteins represent a new class of human neurotherapeutics. Biotechnol. Bioneg. 2007;97: 1376–1386. © 2007 Wiley Periodicals, Inc.
Model Studies on a Carprofen Derivative as Dual Photosensitizer for Thymine Dimerization and (6–4) Photoproduct Repair
Authors: Trzcionka Jérôme , Lhiaubet‐Vallet Virginie , Paris Cecilia , Belmadoui Noureddine , Climent Maria José , Miranda Miguel Angel 
Published: February 2007

AbstractCyclobutane pyrimidine dimers (CPD) and (6–4) photoproducts are among the main UV‐induced DNA lesions. Both types of damage are mostly repaired in prokaryotes by photolyase enzymes. The repair mechanism of (6–4) photolyases has still not been fully elucidated, but it is assumed that back rearrangement to the oxetane occurs prior to repair. In this work, a non‐steroidal anti‐inflammatory drug derivative corresponding to the dechlorinated methyl ester of carprofen (namely methyl 2‐(carbazol‐2‐yl)propanoate, PPMe) has been used to achieve the photosensitized cycloreversion of model oxetanes (formally resulting from photocycloaddition between benzophenone and 1,3‐dimethylthymine or 2′‐deoxyuridine), by employing fluorescence spectroscopy, laser flash photolysis, HPLC and NMR. Although PPMe is able to photoinduce the cycloreversion of both oxetanes, the fluorescence quenching of PPMe is faster for the 2′‐deoxyribose‐containing oxetane; this underlines the importance of the structure in such studies. Moreover, PPMe was shown to photoinduce the formation of thymidine cyclobutane dimers through a triplet–triplet energy transfer from a vibrationally excited state, as suggested by the enhanced PPMe triplet quenching by thymidine with increasing temperature. These results reveal a dual role of PPMe in DNA photosensitization, in that it photoinduces either damage or repair.
Imidazole Coordinated Sandwich‐type Antimony Poly‐oxotungstates Na9[{Na(H2O)2}3{M(C3H4N2)}3(SbW9O33)2]·xH2O (M=NiII, CoII, ZnII, MnII)
Authors: Cui Rui‐Rui , Wang Hu‐Lin , Yang Xin‐Yu , Ren Shu‐Hu , Hu Huai‐Ming , Fu Feng , Wang Ji‐Wu , Xue Gang‐Lin 
Published: February 2007

AbstractThe imidazole covalently coordinated sandwich‐type heteropolytungstates Na9[{Na(H2O)2}3{M(C3H4N2)}3‐ (SbW9O33)2]·xH2O (M=NiII, x=32; M=CoII, x=32; M=ZnII, x=33; M=MnII, x=34) were obtained by the reaction of Na2WO4·2H2O, SbCl3·6H2O, NiCl2·6H2O [MnSO4·H2O, Co(NO3)2·6H2O, ZnSO4·7H2O] and imidazole at pH≈7.5. The structure of Na9[{Na(H2O)2}3{Ni(C3H4N2)}3(SbW9O33)2]·32H2O was determined by single crystal X‐ray diffraction. Polyanion [{Na(H2O)2}3{Ni(C3H4N2)}3(SbW9O33)2}3]9− has approximate C3v symmetry, imidazole coordinated six‐nuclear cluster [{Na(H2O)2}3{Ni(C3H4N2)}3]9+ is encapsulated between two (α‐SbW9O33)9−, the three rings of imidazole in the polyanion are perpendicular to the horizontal plane formed by six metals (Na‐Ni‐Na‐Ni‐Na‐Ni) in the central belt, and π‐stacking interactions exist between imidazoles of neighboring polyanions with dihedral angel of 60°. The compounds were also characterized by IR, UV‐Vis spectra, TG and DSC, and the thermal decomposition mechanism of the four compounds was suggested by TG curves.
Transesterification Reaction of Dimethyl Terephthalate by 2‐Ethylhexanol in the Presence of Heterogeneous Catalysts under Solvent‐free Condition
Authors: Firdovsi Seyidov Tataroglu , Yagoub Mansoori , Parvin Alizadeh Eslamia 
Published: February 2007

AbstractIn this study, the synthesis of bis‐(2‐ethylhexyl) terephthalate, via the transesterification reaction of dimethyl terephthalate (DMT) by 2‐ethylhexanol in the presence of different heterogeneous catalysts, such as Pb(OAc)2·3H2O, Cd(OAc)2·2H2O, Zn(OAc)2·2H2O, Hg(OAc)2, Ca(OAc)2·H2O, Cu(OAc)2·H2O, NaOAc, CaCO3, CaO, ZnSO4·7H2O, and sulfated zirconia, has been investigated. The reactivity of the catalysts in the reaction progress has been studied and compared. It was found that, hydrated cadmium acetate and sulfated zirconia were reactive catalysts to this reaction. The extent of transesterification of methyl ester groups reached up to 93% and 85.6% using these catalysts, respectively.
Measurement of antigen specific immune responses: 2006 update
Authors: Pira Giuseppina Li , Kern Florian , Gratama Jan , Roederer Mario , Manca Fabrizio 
Published: February 2007

AbstractMeasuring antigen‐specific immune responses (MASIR) is essential for basic immunological research and in the clinical setting. Numerous techniques have been used and the recent years have witnessed a flourishing of flow cytometry based methods for the identification of antigen specific T cells, in addition to other methodologies. The second MASIR conference held in Santorini, Greece, from 14 to 18 June 2006 has been a forum for the discussion of methodological issues and for research or clinical applications of these techniques, as reviewed here. In addition to flow cytometry based techniques, other emerging techniques with different degrees of complexity can be applied. These novel methods are highly promising in numerous conditions to look for correlates of protection, to test responses to natural infections or to vaccination trials, to evaluate the immune status of immunocompromised patients and to monitor persistence and function of specific T cells administered as adoptive therapy. © 2007 Clinical Cytometry Society
The Lower Cretaceous Chañarcillo and Neuquén Andean basins: ammonoid biostratigraphy and correlations
Authors: Aguirre‐Urreta M. Beatriz , Mourgues F. Amaro , Rawson Peter F. , Bulot Luc G. , Jaillard Etienne 
Published: February 2007

AbstractThe Chañarcillo and Neuquén basins of the Central Andes shared a common geological history in the earlier part of the Early Cretaceous but from Barremian times onward their evolution began to diverge, probably due to an increasing activity of an intervening volcanic arc. The Berriasian to Lower Barremian sequences were mainly marine and include rich ammonoid faunas, with many taxa in common to both the basins. They include both Andean and near‐pandemic forms, the latter providing some good correlation levels with the ‘standard’ Mediterranean sequence. Marine conditions persisted in the Chañarcillo Basin till Early Albian times; the associated ammonoid faunas include pandemic, Pacific and Antarctic genera. In contrast, in the Neuquén Basin evaporites and continental clastics of the Huitrín Formation mark the beginning of a long disconnection with the Pacific Ocean, though a short‐lived marine incursion is represented by the carbonates of La Tosca Member of the Huitrín Formation. The ammonoid faunas of the two basins are compared here, and a detailed biostratigraphic division of the sequences is discussed and compared with the Mediterranean succession. Copyright © 2007 John Wiley & Sons, Ltd.
Gender and endogenous levels of estradiol do not influence adult hippocampal neurogenesis in mice
Authors: Lagace Diane C. , Fischer Stephanie J. , Eisch Amelia J. 
Published: February 2007

AbstractIn several species, including rat and vole, the proliferation of new neurons in the adult dentate gyrus (DG) subgranular zone (SGZ) is influenced by both gender and endogenous levels of the gonadotropic steroid hormone estradiol. However, little is known about how adult neurogenesis is regulated by these factors in the mouse. We report here that adult C57BL/6 mice do not have gender differences in hippocampal proliferation or neurogenesis. In addition, the production of new SGZ cells in female mice was not influenced by estrous cycle or after ovariectomy, suggesting that fluctuations in endogenous estradiol levels do not alter adult neurogenesis in the mouse. Both male and female mice had a greater number of BrdU‐immunoreactive SGZ cells following chronic treatment with fluoxetine. This demonstrates a parallel proliferation response in both genders, and opens avenues for addressing the neurogenesis hypothesis of depression in female rodents. These findings underscore a distinct regulation of adult neurogenesis in mice vs. other rodents, and are discussed in regard to their implications for the study of adult hippocampal neurogenesis. © 2007 Wiley‐Liss, Inc.
The Seasonal Succession of Biotic Communities in Wetlands of the Tropical Wet‐and‐Dry Climatic Zone: V. Aquatic Invertebrate Communities in the Pantanal of Mato Grosso, Brazil
Authors: Heckman Charles W. 
Published: February 2007

AbstractThe results of a 3 1/2 year study in the Pantanal of Mato Grosso revealed that the life cycles of the invertebrates are profoundly influenced by the annual alternations between a period of very heavy rainfall and several months during which almost no rain falls. A very pronounced effect on the biota is the elimination of many species present in neighboring regions but without the ability to survive periods of adverse conditions resulting from the alternations between flood and dryness. However, those species with suitable adaptations are able to produce very large populations. The annual activity cycles of the invertebrates must not only be timed to the seasonal weather conditions but also to the activities of other species in the food web. They must be adapted to periods of surplus alternating with scarcity of food and predator pressure, which exert great influence on the development of the populations. Of the 256 species considered, most have the ability to produce offspring throughout the year whenever conditions are conducive, but there are also a considerable number which have life cycles apparently including only one reproductive period each year. The general effect of the seasonal changes on the aquatic community of the wetland is to greatly reduce species diversity but to allow the production of vast numbers of those species that have successfully adapted to the conditions. This adaptation of the aquatic species usually entails a dormant stage or a terrestrial one as well as a considerable rate of reproduction to offset losses during periods of unfavorable conditions. The invertebrate fauna includes several taxa represented overwhelmingly by cosmopolitan and circumtropical species, including Rotifera and Gastrotricha, but the great majority of the species are endemic to South America.
Spatio‐Temporal Distribution and Ecological Preferences of Coexisting Hydropsychid Species (Trichoptera) in Two Mediterranean River Basins (S Spain)
Authors: Gallardo‐Mayenco Alfonso , Prenda José , Toja Julia 
Published: February 2007

AbstractThe hydropsychids of two Mediterranean river basins in southern Spain (Guadaira and Guadalete) were investigated from January 1988 to January 1989. The distribution of hydropsychids along an environmental gradient related to altitude varied depending on species. Two distinct species assemblages were observed. one located in the lower altitude sites (the “downstream assemblage” comprising Hydropsyche pictetorum, Hydropsyche exocellata and Cheumatopsyche lepida) and the other in the upper‐most areas (the “upstream assemblage” comprising Hydropsyche punica, Hydropsyche infernalis, Hydropsyche instabilis), which displayed a statistically significant preference for this type of habitat. Finally, H. pictetorum, selected the lowest sites. From a temporal point of view most species displayed a high variability in density dynamics between sites, suggesting a strong plasticity in life‐cycle phenology.
Limnological Characteristics of 70 Lakes Spanning Arctic Treeline from Coronation Gulf to Great Slave Lake in the Central Northwest Territories, Canada
Authors: Rühland Kathleen , Smol John P. 
Published: February 2007

AbstractLatitudinal transects across subpolar ecozones display striking changes in lakewater chemistry reflecting steep gradients in vegetation, climate, and other variables. This paper explores the relationships among chemical and physical lakewater characteristics of 70 lakes spanning arctic treeline in Canada's Central Northwest Territories. Principal components analysis (PCA) was used to examine trends and relationships among environmental variables and these 70 sites. In general, lakes in this data set were dilute, slightly acidic to slightly alkaline, and nutrient‐poor. However, a strong trend toward more concentrated lakewater conditions in densely forested areas was observed relative to tundra regions. Interrelationships among measured limnological variables appear to be strongly influenced by catchment characteristics associated with proximity of sites to treeline.
Maghnite, a Green Catalyst for Cationic Polymerization of Vinylic and Cyclic Monomers
Authors: Belbachir M. , Harrane A. , Megharbi R. 
Published: February 2007

AbstractMaghnite‐H is a nontoxic catalyst for cationic polymerization of vinylic and heterocyclic monomers. This catalyst is issued from the proton exchange of Algerian montmorillonite clay. One application of this catalyst is to produce polydioxolane derivatives. The polymerization of 1,3‐dioxolane catalyzed by Maghnite‐H; (Mag‐H), was investigated. The cationic ring‐opening polymerization of 1,3‐dioxolane was initiated by Mag‐H at different temperatures (20, 30, 50, and 70 °C) in bulk and in a solvent (dichloromethane). The effects of the amount of Mag‐H and the temperature were studied. The polymerization rate and the average molecular weights increased with an increase in the temperature and the proportion of the catalyst. These results indicated the cationic nature of the polymerization and suggested that the polymerization was initiated by proton addition to the monomer from Mag‐H. Moreover, we used a simple method, in one step in bulk and in solution at room temperature (20 °C), to prepare a telechelic bismacromonomer: bis‐unsaturated poly(1,3‐dioxolane).
Water‐Soluble Polyelectrolytes with Metal Ion Removal Ability by Using the Liquid Phase Based Retention Technique
Authors: Rivas Bernabé L. , Pooley S. Amalia , Pereira Eduardo D. , Maureira Antonio 
Published: February 2007

AbstractWater‐soluble polyelectrolytes containing carboxylic acid groups were investigated as polychelatogens, in view to study their metal ion binding properties, using the liquid‐phase polymer‐based retention technique under different experimental conditions. The divalent metal ions investigated were: Co2+, Cu2+, Zn2+, and Cd2+. When the pH increased above 3, and especially at pH 5, metal ion retention capability increased as the majority of the functional groups are carboxylate, which can form more stable complexes with the metal ions. The retention capability also depended on the structure of the polyelectrolyte and the filtration factor, Z.
Characterization of an Epoxy Resin Modified with Natural Oil‐Based Reactive Diluents
Authors: Czub Piotr 
Published: February 2007

AbstractModified natural oils ‐ epoxidized soybean and rapeseed oils were tested as reactive diluents for viscosity regulation of Bisphenol A‐based low‐molecular‐ weight epoxy resin. Satisfactory viscosity reducing ability of epoxidized oils as well as non‐Newtonian rheological behaviour of the resin diluted with modified oils were demonstrated. Co‐crosslinking of mixed oil‐resin compositions using isophorone diamine was studied showing essential decreasing of the reaction heat and slight increasing of the peak maximum temperature. Mechanical properties, thermal stability, water absorption and chemical resistance of the epoxy resin modified with natural oils were also investigated.
Structural Analysis of (LDPE) and (HDPE) Films Biodegraded in Sanitary Landfill‐ II
Authors: Grisa Ana M.C. , Zeni Mara 
Published: February 2007

AbstractThe use of the polymeric commodities LDPE and HDPE in the most varied industrial applications and for economic interests, it produces discards in the waste, and great demand of the same ones in the sanitary landfill. In this work we have studied degradation/biodegradation of the polyethylene (PE) in the landfill São Giácomo in Caxias do Sul, Brazil. The PE was collected in cell C4 with 94 months of age and different depths (11 to 16 m). The samples films was analyzed thermogravimetric (TGA), morphologic (SEM) and structural (FT‐IR) determinations of these degraded materials in landfill. The samples in the waste presented the one degradation pick and for the LDPE mass loss it increases and for HDPE mass loss creases with the dump. Evidenced structural changes with absorbency increment corresponding mainly to vibrations in new frequencies. The morphologic analyses (SEM) the films samples they present scales and fissures.
Synthesis and properties of hyperbranched polybenzimidazoles via A2 + B3 approach
Authors: Xu Hongjie , Chen Kangcheng , Guo Xiaoxia , Fang Jianhua , Yin Jie 
Published: February 2007

AbstractHyperbranched polybenzimidazoles (HBPBIs) were successfully synthesized by condensation polymerization of 1,3,5‐benzenetricarboxylic acid (BTA) and 3,3′‐diaminobenzidine (DAB) in polyphosphoric acid (PPA) at 190 °C. Different monomer addition manners and molar ratios resulted in different polymers, that is, simultaneous addition of BTA and DAB with the molar ratio of 1:1 (manner 1) gave carboxyl‐terminated HBPBI (HBPBI‐1), whereas the addition of BTA portion‐wise to DAB solution in PPA with the molar ratio of DAB:BTA = 2:1 (manner 2) yielded amine‐terminated HBPBI (HBPBI‐2). The free carboxyl and amino groups of HBPBI‐1 and HBPBI‐2 could further react with o‐diaminobenzene and benzoic acid, respectively, to form the chemically modified polymers. Except HBPBI‐2, all the HBPBIs showed good solubility in some organic solvents (e.g., dimethyl sulfoxide and N,N‐dimethylacetamide). Thermogravimetric analysis measurement revealed that HBPBIs except HBPBI‐1 had high thermal stability (>450 °C). HBPBI membranes with good mechanical properties were obtained by crosslinking treatment of partially chemically modified HBPBIs with terephthaldehyde (TPA) during the film cast process. The HBPBI membranes had high phosphoric acid uptake and the phosphoric acid‐doped HBPBI‐6 (40% o‐diamino groups were reacted with benzoic acid) membrane showed higher tensile strength than the acid‐doped commercial PBI despite the higher doping level of the former. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1150–1158, 2007
Tight binding modelling of electronic band structure in conventional InGaN/GaN and dilute GaAsN/GaAs nitride heterostructures
Authors: Hakan Gürel H. , Akıncı Özden , Ünlü Hilmi 
Published: February 2007

AbstractWe utilize a semi‐empirical sp3s * tight binding model to investigate the strain and composition effects on electronic structure of conventional InGaN/GaN and dilute GaAsN/GaAs cubic nitride heterostructures. The model includes the second nearest neighbor (2NN) atomic interactions, spin‐orbit splitting and nonlinear composition variation of atomic energies and bond lengths of ternaries. Results show that band gaps of conventional InGaN increase with composition for 0 < x < 1. However, the Γ band gap of dilute GaAsN decreases with composition for x < 0.25 and then starts to increase for 0.26 < x < 1. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A semiconductor based pump‐probe system and its application to THz spectroscopy
Authors: Vickers A. J. , Dudley R. , Henning I. , Ma Y. 
Published: February 2007

AbstractIn this work a description of a semiconductor laser based system is presented that can be utilised in many pump‐probe experiments and in particular as the basis for a THz spectrometer. There are two methods described, one which has a stepping time delay function and the other which has a sweep time delay function. These two methods are achieved in the first case by a manipulation of the relative gain switching of two semiconductor lasers and in the second case by a gain switching of two semiconductor lasers with slightly different RF frequencies. The time delay by cross‐correlating the two gain switched laser outputs on a silicon APD via two photon absorption is demonstrated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel synthesis route for a gold–polymer soft composite material
Authors: Mallick Kaushik , Witcomb Mike , Scurrell Mike 
Published: February 2007

AbstractFigure 3 of the Rapid Research Letter by Mallick et al. [phys. stat. sol. (RRL) 1, No. 1, R1–R3 (2007)] is presented here in its correct form. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Brandschaden und Instandsetzung der Wiehltalbrücke im Zuge der A4, Köln – Olpe
Authors: Eisel Hans , Palm Norbert , Prehn Wolfgang , Sedlacek Gerhard 
Published: February 2007

AbstractAm 26. August 2004 hat ein tragischer Verkehrsunfall eines Tankfahrzeuges auf der Wiehltalbrücke zu dessen Absturz von der Brücke und zu erheblicher Brandeinwirkung auf den Stahlüberbau im ersten Brückenfeld geführt.Der Beitrag schildert die Sofortmaßnahme zur Sicherung der Brücke, provisorische Verstärkungen zur schnellen Wiederaufnahme des Autobahnverkehrs und die endgültige Instandsetzung zur Wiederherstellung des ursprünglichen Brückenzustandes.Charakteristisch für die Robustheit der Stahlkonstruktion gegenüber Brand ist, daß trotz Flammtemperaturen um 1200 °C die Objekttemperatur nur etwa 500 °C erreichte, so daß die Schäden in Grenzen blieben.Die darauf schließenden Werkstoffbefunde wurden durch einen rechnerischen Nachweis mit Naturbrand bestätigt.