bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ein neuer Zugang zu Thiocarbonyl‐Verbindungen
Authors: Schaumann Ernst , Wriede Ulrich , Rühter Gerd 
Published: September 2007

AbstractDas vollständige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1983, 63. DOI: 10.1002/ange.198300630
NMR‐Untersuchungen an Hefen, die auf Substraten mit “Zähmung”‐Radioaktivität kultiviert wurden
Authors: Basosi Riccardo , Rossi Claudio , Tiezzi Enzo , Valensin Gianni 
Published: September 2007

AbstractDas vollständige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1983, 57. DOI: 10.1002/ange.198300570
Kinetische und thermodynamische Kontrolle der Reaktion von (Ph3P)2PtO2 mit (H)‐2‐Butenal
Authors: Broadhurst Michael J. , Brown John M. , John Robert A. 
Published: September 2007

AbstractDas vollständige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1983, 1. DOI: 10.1002/ange.198300010
Diastereo‐ und enantioselektive Synthese von (1H,3H)‐Caronaldehydsäure‐methylester und (1H,3H)‐Chrysanthemumsäure‐methylester aus (H)‐Glycerinaldehyd‐acetonid
Authors: Mulzer Johann , Kappert Michael 
Published: September 2007

AbstractDas vollständige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1983, 23. DOI: 10.1002/ange.198300230
O‐Glycopeptid‐Synthese unter Verwendung von 9‐Fluorenylmethoxycarbonyl‐(Fmoc‐)geschützten Bausteinen
Authors: Schultheiß‐Reimann Petra , Kunz Horst 
Published: September 2007

AbstractDas vollständige Manuskript dieser Zuschrift erscheint in: Angew. Chem. Suppl. 1983, 39. DOI: 10.1002/ange.198300390
The Renaissance of H/D Exchange
Authors: Atzrodt Jens , Derdau Volker , Fey Thorsten , Zimmermann Jochen 
Published: September 2007

AbstractThe increasing demand for stable isotopically labeled compounds has led to an increased interest in H/D‐exchange reactions at carbon centers. Today deuterium‐labeled compounds are used as internal standards in mass spectrometry or to help elucidate mechanistic theories. Access to these deuterated compounds takes place significantly more efficiently and more cost effectively by exchange of hydrogen by deuterium in the target molecule than by classical synthesis. This Review will concentrate on the preparative application of the H/D‐exchange reaction in the preparation of deuterium‐labeled compounds. Advances over the last ten years are brought together and critically evaluated.
Kinetic study of the decompositions involved in the thermal degradation of commercial azodicarbonamide
Authors: Reyes‐Labarta J. A. , Marcilla A. 
Published: September 2007

AbstractThe transitions and reactions involved in the thermal treatment of several commercial azodicarbonamides (ADC) in an inert atmosphere have been studied by dynamic thermogravimetry analysis (TGA), mass spectrometry and Fourier transform infrared (FTIR) spectroscopy. A pseudo‐mechanistic model, involving several competitive and non‐competitive reactions, has been suggested and applied to the correlation of the weight loss data. The model applied is capable of accurately representing the different processes involved, and can be of great interest in the understanding and quantification of such phenomena, including the simulation of the instantaneous amount of gases evolved in a foaming process. In addition, a brief discussion on the methodology related to the mathematical modeling of TGA data is presented, taking into account the complex thermal behaviour of the ADC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of polyacrylamide cryogels produced from a high‐molecular‐weight precursor. II. The influence of the molecular weight of the polymeric precursor
Authors: Ivanov Roman V. , Lozinsky Vladimir I. , Noh Seok Kyun , Lee Yong Rok , Han Sung Soo , Lyoo Won Seok 
Published: September 2007

AbstractPolyacrylamide gels and cryogels were prepared by the crosslinking reaction of polyacrylamide (a polymeric precursor) with glutaric aldehyde (a crosslinking agent) in liquid and moderately frozen aqueous media, respectively. Polymeric precursors of different viscosity‐ averagemolecular weights (0.3, 1, 3, and 9 MDa) were used. The molecular weight of the precursors, as well as the reaction temperature and concentration of the crosslinking agent, exerted a pronounced influence on the efficiency of gelation (gel fraction yield) and on the properties (swelling capability) and structural peculiarities of the resulting gels (reference samples) and cryogels. The highest efficacy was inherent in the cryotropic gelation process when the polymeric precursor had a molecular weight of about 3 MDa, whereas the implementation of polyacrylamides of lower (0.3 or 1 MDa) or higher (9 MDa) molecular weights diminished the gel formation efficiency. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Evaluating cell wall structure and composition of developing cotton fibers using Fourier transform infrared spectroscopy and thermogravimetric analysis
Authors: Abidi Noureddine , Hequet Eric , Cabrales Luis , Gannaway John , Wilkins Thea , Wells Leslie W. 
Published: September 2007

AbstractUniversal attenuated total reflectance Fourier transform infrared (UATR‐FTIR) spectroscopy and thermogravimetric analysis (TGA) were used to investigate the structural changes of cotton (Gossypium hirsutum L.) fibers as a function of developmental programming. The presence of noncellulosic compounds (wax, protein, hemicelluloses, pectic substances, amino acids, etc.) was evident from FTIR spectra of fibers at 10, 14, 17, and 20 dpa (day postanthesis). The vibration corresponding to the noncellulosic compounds disappeared at 36 dpa. Furthermore, independent TGA analysis supported the results obtained with FTIR, showing that the transition from primary cell wall synthesis to secondary cell wall synthesis occurs at or around 20 dpa. This study is the first to report on the use of the UATR‐FTIR and TGA to elucidate structural changes during cotton fiber development. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Functional properties of thermoformed wheat gluten/montmorillonite materials with respect to formulation and processing conditions
Authors: Angellier‐Coussy Hélène , Torres‐Giner Sergio , Morel Marie‐Hélène , Gontard Nathalie , Gastaldi Emmanuelle 
Published: September 2007

AbstractWheat gluten (WG)/montmorillonite (MMT) films were prepared by a thermomechanical process consisting of first mixing the components in a two‐blade, counter‐rotating device and second thermoforming the obtained dough. A significant loss in protein solubility due to the formation and rearrangement of disulfide bonds was observed upon mixing and thermoforming. In the range of studied glycerol contents (25–42.8 wt %), it was shown that glycerol had no significant effect on the mechanical properties or water sensitivity of WG‐based films. Increasing the thermoforming temperature from 60 to 120°C led to considerable improvements of the mechanical properties (increases in both the stress and strain at break) and a significant reduction of the water sensitivity. The introduction of MMT (up to 5 wt %) allowed the achievement of mechanical properties that were not possible by just the variation of the glycerol content and the processing temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of a heterogeneous hollow‐fiber affinity membrane having a mercapto chelating resin and its recovery of Hg2+ cations
Authors: Wang Bing , Liu Wei , Huang Lei 
Published: September 2007

AbstractA kind of heterogeneous hollow‐fiber affinity filter membrane with a high chelating capacity for Hg2+ was prepared by phase separation with blends of a mercapto chelating resin and polysulfone as the membrane materials, N,N‐dimethylacetamide as the solvent, and water as the extraction solvent. The adsorption isotherms of the hollow‐fiber affinity filter membrane for Hg2+ were determined. The heterogeneous hollow‐fiber affinity filter membrane was used for the adsorption of Hg2+ cations through the coordination of the mercapto group and Hg2+ cations, and the effects of the morphology and structure of the affinity membrane on the chelating properties were investigated. The chelating conditions, including the chelating resin grain size, pH value, concentration of the metallic ion solution, mobile phase conditions, and operating parameters, had significant effects on the chelating capacity of the hollow‐fiber affinity filter membrane. The results revealed that the greatest chelating capacity of the hollow‐fiber affinity filter membrane for Hg2+ was 1090 μg/cm2 of membrane under appropriate conditions, and the adsorption isotherms of Hg2+ could be described by the Langmuir isotherm. The dynamic chelating experiments indicated that the hollow‐fiber affinity membrane could be operated at a high feed flow rate and that large‐scale removal of Hg2+ could be realized. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Lower critical solution temperature behavior of amphiphilic copolymers based on polyaspartamide derivatives
Authors: Bach Quang Vu , Moon Jong‐Rok , Lee Doo Sung , Kim Ji‐Heung 
Published: September 2007

AbstractNovel copolymers consisting of poly(N‐isopropylaminoethyl‐co‐6‐hydroxyhexyl aspartamide) and poly (N‐isopropylaminoethyl‐co‐hexyl aspartamide) were prepared from polysuccinimide, which was the thermal polycondensation product of L‐aspartic acid, via a ring‐opening reaction with 6‐amino‐L‐hexanol (AH) or hexylamine (HA) and N‐isopropylethylenediamine at different ratios. The copolymers, containing 75–90 mol % of AH and 35–45 mol % of HA, produced thermoresponsive polymers through their lower critical solution temperatures (LCSTs) in aqueous solution. We could control the LCST could be controlled by modifying the hydrophobic–hydrophilic balance by changing the content of AH or HA. The pH dependencies of the LCST were opposite in these two different copolymer systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Determining the context of text using augmented latent semantic indexing
Authors: Rishel Tom , Perkins Louise A. , Yenduri Sumanth , Zand Farnaz 
Published: September 2007

AbstractLatent semantic analysis has been used for several years to improve the performance of document library searches. We show that latent semantic analysis, augmented with a Part–of–Speech Tagger, may be an effective algorithm for classifying a textual document as well. Using Brille's Part–of–Speech Tagger, we truncate the singular value decomposition used in latent semantic analysis to reduce the size of the word–frequency matrix. This method is then tested on a toy problem, and has shown to increase search accuracy. We then relate these results to natural language processing and show that latent semantic analysis can be combined with context free grammars to infer semantic meaning from natural language. English is the natural language currently being used.
Developments and constraints in fermentative hydrogen production
Authors: Bartacek Jan , Zabranska Jana , Lens Piet N. L. 
Published: September 2007

AbstractFermentative hydrogen production is a novel aspect of anaerobic digestion. The main advantage of hydrogen is that it is a clean and renewable energy source/carrier with high specific heat of combustion and no contribution to the Greenhouse effect, and can be used in many industrial applications. This review discusses fermentative hydrogen production from various points of view. First, the theoretical principles of the biological processes taking place in hydrogen production, as well as the organisms responsible for this process, are described. Second, practical aspects of fermentative hydrogen production are overviewed. Suitable conditions for the hydrogen‐producers (pH and temperature), suitable substrates for hydrogen production and applicable reactor designs are discussed. Finally, the challenges faced by fermentative hydrogen production are discussed. Current research directions are listed together with the most important problems currently constraining full‐scale application. © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd
Mung bean lipoxygenase in the production of a C6‐aldehyde. Natural green‐note flavor generation via biotransformation
Authors: Chow Yvonne , Liew Tze Huey , Keh Hui Hui , Ko Amy , Puah Sze Min , Nguyen Thi Bich Van , Zaman Nurulhida Binte Gul , Wu Jinchuan , Talukder Md Mahabubur Rahman , Choi Won Jae 
Published: September 2007

AbstractMung bean was investigated as a novel source of lipoxygenase in the natural production of the green‐note aroma compound hexanal. Lipoxygenase extracted from mung bean catalyzed the oxidative reaction of linoleic acid, after which the intermediate hydroperoxide compound was split via green bell pepper hydroperoxide lyase to produce hexanal. In comparison to soybean lipoxygenase, mung bean lipoxygenase was found to be a good substitute as it produced 15.4 mM (76% yield) hexanal while soybean gave 60% yield. The mung bean pH profile comprised a wide peak (optimum pH 6.5) representing lipoxygenase‐2 and lipoxygenase‐3 isozymes, whereas two narrower peaks representing lipoxygenase‐1 and lipoxygenase‐2/3 isozymes were observed for soybean (optimum pH 10). Extraction at pH 4.5 was preferred, at which specific lipoxygenase activity was also the highest.
The chakragati mouse: A mouse model for rapid in vivo screening of antipsychotic drug candidates
Authors: Dawe Gavin S. , Ratty Anil K. 
Published: September 2007

AbstractThe chakragati (ckr) mouse is a serendipitously discovered insertional transgenic mutant that exhibits circling and hyperactivity. Studies of social behavior, sensorimotor gating and ventricular anatomy suggest that the ckr mouse models aspects of schizophrenia. The underlying genetic and neurodevelopmental mechanisms remain to be elucidated but appear to result in a hemispheric asymmetry in striatal D2‐like dopamine receptors. The circling is inhibited by administration of antipsychotic drugs and so lends itself to in vivo prospective screening for novel molecules with antipsychotic‐like activity. Using the ckr mouse we have applied an in vivo first approach to screening for antipsychotic drug candidates. This offers the advantage of early indication of central nervous system bioavailability and potential toxicological concerns. Additionally, in vivo first screening in the ckr mouse is not biased by any particular neurotransmitter hypothesis of the disease, and so has the potential to identify compounds modifying the behavioral output by novel mechanisms of interaction with the underlying brain circuitry. Thus, in contrast to the classical strategy of hypothesis‐driven in vitro screening for drugs fitting a “receptor model” of the disease, the ckr mouse screen has greater potential to identify lead molecules for a new generation antipsychotics with novel mechanisms of action.
Comprehensive design of rotating shafts and a software for designing and selecting of rolling‐contact bearings
Authors: Taskesen Ahmet , Mendi Faruk , Kulekci Mustafa Kemal , Basak Hudayim 
Published: September 2007

AbstractIn this study a computer program was developed using Visual Basic and Visual LISP programming languages to comprehensively analyze the strength, deformation, vibration, manufacturing, and drawing of a rotating circular stepped shaft. These shafts have a variety of power transmitting mechanical elements (components), such as pairs of gears, and pulleys that are modeled in 3D. In addition, force and moment analyses of these elements running on the shafts were examined. Notch sensitivity and stress concentration factors given graphically were formulated using the finite difference method. Vibration analysis was also included to the software. Furthermore, to select the best rolling‐contact bearings, an expert system requiring the knowledge‐based technique was employed. The user is given the choice of shaft material and other parameters. After saving the data regarding calculated and designed shaft, these data are transferred to the graphical environment for detail drawing and CNC code generation of the shaft. A program, which is called shaft and gear design program, has been developed for this process. © 2007 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 214–225, 2007; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20152
Effective page refresh policy
Authors: Gao Kai 
Published: September 2007

AbstractWeb pages are created or updated randomly. As for a search engine, keeping up with the evolving Web is necessary. But previous studies have shown the crawler's refresh ability is limited because it is not easy to detect the change instantly, especially when the resources are limited. This article concerns modeling on an effective Web page refresh policy and finding the refresh interval with minimum total waiting time. The major concern is how to model the change and which part should be updated more often. Toward this goal, the Poisson process is used to model the process. Further, the relevance is also used to adjust the process, and the probability on some sites is higher than others so these sites will be given more opportunities to be updated. It is essential when the bandwidth is not wide enough or the resource is limited. The experimental results validate the feasibility of the approach. On the basis of the above works, an educational search engine has been developed. © 2007 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 240–247, 2007; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20155
Differences in Substrate Specificity of C(5)‐Substituted or C(5)‐Unsubstituted Pyrimidine Nucleotides by DNA Polymerases from Thermophilic Bacteria, Archaea, and Phages
Authors: Sawai Hiroaki , Nagashima Junichi , Kuwahara Msayasu , Kitagata Rina , Tamura Takehiro , Matsui Ikuo 
Published: September 2007

AbstractThe pyrimidine bases of RNA are uracil (U) and cytosine (C), while thymine (T) and C are used for DNA. The C(5) position of C and U is unsubstituted, whereas the C(5) of T is substituted with a Me group. Miller et al. hypothesized that various C(5)‐substituted uracil derivatives were formed during chemical evolution, and that C(5)‐substituted U derivatives may have played important roles in the transition from an ‘RNA world’ to a ‘DNA‐RNA‐protein world’. Hyperthermophilic bacteria and archaea are considered to be primitive organisms that are evolutionarily close to the universal ancestor of all life on earth. Thus, we examined the substrate specificity of several C(5)‐substituted or C(5)‐unsubstituted dUTP and dCTP analogs for several DNA polymerases from hyperthermophilic bacteria, hyperthermophilic archaea, and viruses during PCR or primer extension reaction. The substrate specificity of the C(5)‐substituted or C(5)‐unsubstituted pyrimidine nucleotides varied greatly depending on the type of DNA polymerase. The significance of this difference in substrate specificity in terms of the origin and evolution of the DNA replication system is discussed briefly.
ipso‐Substitution: A General Biochemical and Biodegradation Mechanism to Cleaveα‐Quaternary Alkylphenols and Bisphenol A
Authors: Gabriel Frédéric L. P. , Cyris Maike , Giger Walter , Kohler Hans‐Peter E. 
Published: September 2007

AbstractSphingobium xenophagumBayram is capable of metabolizing 4‐alkoxyphenols and endocrine disruptiveα‐quaternary 4‐nonylphenols by anipso‐substitution mechanism that involves ring hydroxylation at the site of the substituent. Here, we show that Bayram'sipso‐hydroxylating activity was able to transform also bisphenol A (=dimethyl‐4,4′‐methylenediphenol; BPA) and 4‐isopropylphenol. We identified six metabolites when resting cells of strain Bayram were incubated with BPA. They were unambiguously characterized by HPLC‐UV, HPLC/MS, and HPLC/MS/MS as hydroquinone, 2‐(4‐hydroxyphenyl)isopropanol, 4‐isopropenylphenol, 4‐isopropylphenol, 4‐hydroxy‐4‐isopropenylcyclohexa‐2,5‐dien‐1‐one, and 4‐hydroxy‐4‐isopropylcyclohexa‐2,5‐dien‐1‐one. In experiments with 4‐isopropylphenol as a substrate, 4‐hydroxy‐4‐isopropylcyclohexa‐2,5‐dien‐1‐one, one of the metabolites from BPA, accumulated to a high degree. We could rationalize the formation of all metabolites by invokingipso‐hydroxylation andipso‐substitution mechanisms. On closer view, also classical bacterial metabolism of BPA can be well rationalized by anipso‐substitution mechanism, albeit withipso‐attack of an internal alkyl radical instead of an activated oxygen species. This highlights the important role ofipso‐substitution as a versatile degradative principle utilized by diverse organisms to degradeα‐quaternary 4‐nonylphenols, 4‐alkoxyphenols, and BPA.
Chemical and Biogeophysical Impact of Four‐Dimensional (4D) Seismic Exploration in Sub‐Saharan Africa, and Restoration of Dysfunctionalized Mangrove Forests in the Prospect Areas
Authors: Osuji Leo C. , Ayolagha G. , Obute G. C. , Ohabuike H. C. 
Published: September 2007

AbstractFour‐dimensional (4D) seismic exploration, an improved geophysical technique for hydrocarbon‐data acquisition, was applied for the first time in the Nembe Creek prospect area of Nigeria. The affected soils were slightly alkalinein situwhen wet (pH 7.2), but extremely acidic when dry (pH 3.0). The organic carbon content (4.6–26.8%) and other physicochemical properties of soils and water (N, P, and heavy‐metal contents,etc.) were higher than the baseline values obtained in 2001 before seismic profiling. Most values also exceeded the baseline compliance standards of theDepartment of Petroleum Resources(DPR), theWorld Health Organization(WHO), and theFederal Environmental Protection Agency(FEPA). Rehabilitation of the affected areas was achieved by stabilizing the mangrove floor by liming and appropriate application of nutrients, followed by replanting the cut seismic lines over a distance of 1,372 km with different mangrove species, including juvenileRhizophora racemosa, R. mangle, andAvicenniaspecies, which were transferred from nursery points. Quicker post‐operational intervention is recommended for future 4D surveys, because the time lag between the end of seismic activity and post‐impact investigation is critical in determining the relationship between activity and impact: the longer the intervening period, the more mooted the interaction.
Diastereoselective Synthesis of Aminobacteriohopanetetrol, a Biomarker for Methanotrophic Bacteria: Confirmation of the Absolute Configuration
Authors: Pan Weidong , Zhang Yongmin , Liang Guangyi , Rohmer Michel , Sinaÿ Pierre , Vincent Stéphane P. 
Published: September 2007

AbstractA short and convenient strategy was developed for the first stereoselective chemical synthesis of aminobacteriohopanetetrol (=(1R,2R,3S,4S)‐5‐amino‐1‐[(22R)‐hopan‐30‐yl]pentane‐1,2,3,4‐tetrol; 1), a typical biomarker for methanotrophic bacteria. Comparison of the NMR spectra of the synthetic and natural (peracetylated) product enabled us to unambiguously corroborate the absolute configuration of the functionalized pentyl side chain of 1.
Ionic Liquids for the Production of Insecticidal and Microbicidal Extracts of the Fungus Cantharellus cibarius
Authors: Cieniecka‐Rosłonkiewicz Anna , Sas Agnieszka , Przybysz Elżbieta , Morytz Bolesław , Syguda Anna , Pernak Juliusz 
Published: September 2007

AbstractDifferent ionic liquids were used as solvents for the effective extraction of the active metabolites of the fruit bodies of C. cibarius. The type of ionic liquid was found to play a significant role in this process. We found that the protic ionic liquid 1‐[(nonyloxy)methyl]‐1H‐imidazol‐3‐ium salicylate (6) is a most‐efficient extracting agent, being superior to classical solvents such as AcOEt or hexane. The obtained extracts generally revealed high insecticidal activities against both house fly and cockroach, with similar potencies as the standard pesticides bromfenvinphos or alphacypermethrin, as well as significant activities against bacteria, yeast, and moulds. Notably, the cidal activities against plant‐pathogenic bacteria were stronger than against human bacterial strains.