bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heiße Quellen am Meeresboden: Erzfabriken in der Tiefsee
Authors: Herzig Peter 
Published: October 2003

AbstractMit der Entdeckung der ersten Metallsulfidablagerungen und 350 °C heißen Black Smoker im Bereich des Ostpazifischen Rückens im Jahre 1979, begann die wissenschaftliche Untersuchung dieser einzigartigen Mineralvorkommen der Tiefsee. Heute sind in den Weltozeanen mehr als 200 Hydrothermalvorkommen bekannt, wovon zirka 30 momentan aktiv sind. Die im Umfeld der heißen Quellen entstehenden Mineralablagerungen sind die rezenten Gegenstücke einer bedeutenden Gruppe von Erzvorkommen (Massive Sulfidlagerstätten), die sich heute an Land befinden, aber ehemals am Grunde von Urozeanen gebildet wurden. Dieser Zusammenhang macht die Black Smoker‐Vorkommen der Tiefsee zu natürlichen Labors der Erzlagerstättenforschung. Zudem haben die zum Teil hohen Bunt‐ und Edelmetallgehalte der Meeresbodenvorkommen bereits zu Überlegungen geführt, diese Vererzungen eines Tages wirtschaftlich und umweltverträglich zu gewinnen. Erste Schritte hierzu sind bereits unternommen worden.
Mephitis mephitis, Du stinkst so sehr!
Authors: Roth Klaus 
Published: October 2003

AbstractWer der übelste Stinker in der Natur ist, darüber sind sich Laien und Fachleute einig: es ist Mephitis mephitis, das gestreifte Stinktier [1]. Es wundert daher nicht, dass nur wenige Wissenschaftler verwegen genug waren, sich an das Stinktier heranzuwagen. Aus ihren Arbeiten wissen wir, dass das Sekret ein hochkomplexer Naturstoff und ein Meisterstück der Schwefelchemie ist.
Polycarbonate
Authors: Hübner Karl 
Published: October 2003

AbstractHeute werden weltweit jährlich fast zwei Millionen Tonnen einer Kunststoffklasse verarbeitet, die in diesen Tagen ihren 50. Geburtstag feiert: Am 17. Oktober 1953 reichten die Farbenfabriken Bayer AG ihren Patentantrag über ein „Verfahren zur Herstellung thermoplastischer Kunststoffe”︁ beim Deutschen Patentamt ein. Es ging um Polycarbonate.
Achieving proportional DiffServ per‐hop behaviour with PLQF
Authors: Li Jung‐Shian , Lai Hsing‐Chien , Lin Yi‐Ting 
Published: October 2003

AbstractWe propose a novel scheme that can provide both delay and loss proportional DiffServ per‐hop behaviour. DiffServ is a framework that can provide different QoS levels to different groups of network users, and eliminate the shortcoming of the best‐effort delivery in today's Internet. The scheme employs probabilistic longest queue first (PLQF) as its forwarding and dropping mechanism. PLQF mainly reacts immediately to the queue‐length fluctuation of each service class, and then decides the probability for each QoS class, which determines the forwarding or dropping behaviour. We couple delay and loss differentiated services in one scheme. The proposed scheme is proven to achieve proportional differentiated services after detailed evaluations. Furthermore, the implementation cost of PLQF is much less than that of the previously proposed schemes, such as WTP and PLR. Copyright © 2003 John Wiley & Sons, Ltd.
Ethical issues in psychotherapy with adolescents
Authors: Koocher Gerald P. 
Published: October 2003

AbstractTreating adolescents in psychotherapy presents a number of unique ethical challenges. Because many adolescents who enter treatment have not yet attained the age of majority, reside in families that include other people with emotional difficulties, attend school, become involved with community agencies (e.g., the courts), and must generally take direction from adult authority figures, the role of the therapist becomes particularly complex. The unique dilemmas include developing specialized clinical competence, treatment contracting, choice of treatment modality, direction of the therapeutic process, and confidentiality. This article discusses the range of ethical concerns involved in treating adolescents and suggests strategies for optimal ethical care. © 2003 Wiley Periodicals, Inc. J Clin Psychol/In Session.
Rab3D redistribution and function in rat parotid acini
Authors: Ngyen Danielle , Jones Antoinette , Ojakian George K. , Raffaniello Robert D. 
Published: October 2003

AbstractAn Erratum has been published for this article in Journal of Cellular Physiology 199: 316, 2004.Rab3D is a low molecular weight GTP‐binding protein believed to be involved with regulated secretion in many cell types. In parotid, Rab3D is localized to secretory granule membranes or present in the cytosol as a complex with Rab escort protein. In the present study, we examined the redistribution of membrane‐associated Rab3D during secretion in permeabilized parotid acini. When permeabilized acini were stimulated with calcium and cAMP, amylase release increased greater than twofold over basal. Quantitative immunoblotting of subcellular fractions revealed that Rab3D did not dissociate from parotid membranes during secretion. Immunohistochemical staining demonstrated that Rab3D co‐localizes with amylase containing granules that are found in the apical pole of the cell. Upon stimulation with calcium and cAMP, Rab3D and amylase immunostaining of granules appeared to be more dispersed. However, Rab3D immunostaining was not observed on the plasma membrane and appeared to reside in the apical cytoplasm. To examine the role of Rab3D in amylase release, cytosolic extracts containing myc‐tagged Rab3D and Rab3DQ81L, a GTP‐binding mutant, were prepared and incubated with streptolysin O‐permeabilized acini. Rab3D, but not Rab3DQ81L, bound to parotid membranes suggesting that Rab3D‐binding to parotid membranes is guanine nucleotide‐dependent. Moreover, wild‐type and mutant Rab3D inhibited agonist‐induced amylase release from permeabilized parotid acini. These observations indicate that in parotid acini, Rab3D does not dissociate from parotid membranes or redistribute to the plasma membrane during secretion, and may play an inhibitory role in regulated secretion. The fact that both wild‐type Rab3D and the GTP‐binding mutant inhibit amylase release suggests that binding of Rab3D to the membrane is not essential for secretory inhibition.
J. Cell. Physiol. 197: 400–408, 2003© 2003 Wiley‐Liss, Inc.
Mineralization of dissolved organic carbon in mineral soil solution of two forest soils
Authors: Schwesig David , Kalbitz Karsten , Matzner Egbert 
Published: October 2003

AbstractDissolved organic carbon (DOC) constitutes an important carbon input flux to forested mineral soils. Seepage from mineral subsoils contains only small amounts of DOC because of mineralization, sorption or the formation of particulate organic matter (POM). However, the relation between these processes is largely unknown. Therefore, the objective of this study was to quantify the mineralization of DOC from different depths of forest soils, and to determine degradation rate constants for rapidly and slowly degradable DOC pools. Mineralization of DOC and formation of POM in mineral soil solution from two forested sites in northern Bavaria (Germany) were quantified in a 97 days laboratory incubation experiment. Furthermore, spectroscopic properties such as specific UV absorption and a humification index derived from fluorescence emission spectrometry were measured before and after incubation. DOC in all samples turned out to belong mainly to the stable DOC pool (> 95 %) with half‐lives ranging from years to decades. Spectroscopic properties were not suitable to predict the mineralization of DOC from mineral soils. However, together with data on DOC from the forest floor and long‐term data on DOC concentrations in the field they helped to identify the processes involved in C sequestration in mineral subsoils. Mineralization, formation of POM, and probably sorption seem all to be responsible for maintaining low concentrations of DOC in the upper mineral soil. DOC below the upper mineral soil is highly resistant to mineralization, and thus the further decrease of DOC concentrations in the subsoil as observed under field conditions cannot be attributed to mineralization. Our results suggest that sorption and to some minor extent the formation of POM may be responsible for C sequestration in the subsoil.
Vertical distribution and bioavailability of 137Cs in organic and mineral soils
Authors: Kruse‐Irmer Sven , Giani Luise 
Published: October 2003

AbstractThe vertical distribution and bioavailability of 137Cs in Histosols and mineral soils with different physicochemical properties from the southeast of Bavaria (Germany) more than ten years after the Chernobyl accident were the focus of this study.The vertical distribution of 137Cs was low in the investigated soils. About 85–98 % of the total 137Cs was located in the upper 10 cm of the mineral soils. Slightly higher 137Cs percentages were observed in deeper soil layers of the peat soils. Although the organic matter is assumed to enhance 137Cs mobility in soils, 137Cs was also located in the upper 10 cm of the peat soils (73–85 %). The highest 137Cs‐activities were found in the humus layers of forest soils, where 45–93 % of the total 137Cs soil inventories were observed. To determine the bioavailability of radiocesium, the soil‐to‐plant transfer of 137Cs and additionally added 134Cs was investigated under controlled conditions. The results revealed that the 134+137Cs soil‐to‐plant transfer factors as well as the percentages of NH4‐exchangeable 134+137Cs were much higher for the peat soils and humus layers than for the mineral soils. Nevertheless, the migration of 137Cs from the humus layers to the underlying soils was low. Considering the high bioavailability and low migration of radiocesium in the humus layers, it is suggested that radiocesium is involved in a shortcut element cycle in the system humus layer‐plant uptake‐litter. Furthermore, the organic matter has to be taken into account for radiocesium immobilization.
α‐Fe layer formation during metal dusting of iron in CO‐H2‐H2O gas mixtures
Authors: Zhang J. , Schneider A. , Inden G. 
Published: October 2003

AbstractThe formation of an α‐Fe layer between cementite and graphite was observed and investigated during metal dusting of iron in CO‐H2‐H2O gas mixtures at both 600°C and 700°C. The condition to form this phenomenon is determined by the gas composition which depends on temperature. The iron layer formation was observed for CO content less than 1 % at 600°C and less than 5 % at 700°C. With increasing CO contents, no α‐Fe layer was detected at the cementite/graphite interface by optical microscopy. In this case cementite directly contacts with the coke layer. The morphologies of the coke formed in the gas mixtures with low CO contents were also analysed. Three morphologies of graphite have been identified with 1 % CO at 600°C: filamentous carbon, bulk dense graphite with columnar structure, and graphite particle clusters with many fine iron containing particles embedded inside. At 700°C with 5 % CO the coke mainly consists of graphite particle clusters with some filamentous carbon at the early stage of reaction. Coke analysis by X‐ray diffraction shows that both α‐Fe and Fe3C are present in the coke. The mechanism of α‐Fe accumulation between cementite and graphite is discussed in this paper.
Aliphatic‐Aromatic Hyperbranched Polyesters by Polycondensation of Potassium 3,5‐Bis(bromomethyl)benzoate: Formation of Cyclic Structures
Authors: Sepulchre Maurice , Sepulchre Marie‐Odile , Belleney Joël 
Published: October 2003

AbstractAliphatic‐aromatic hyperbranched polyesters of reasonable degrees of branching (DB's) but of relatively low molar masses were prepared from 3,5‐bis(bromomethyl)benzoic acid (2a). 2a was synthesized by radical bromination of 3,5‐dimethylbenzoic acid. The polymerization of 2a and that of the potassium salt of 2a (2K), both carried out in the presence of a potassium monocarboxylate (RCOOK), led to directly derivatized polyesters. Polyesters bearing free CH2Br groups were obtained by polymerization of 2K alone or in the presence of 2,4,6‐tris(bromomethyl)mesitylene (TBMM) or by polymerization of 2a in the presence of RCOOK provided that 1 ≤ [RCOOK]/[2a] < 2. These polyesters were later derivatized by reaction with RCOOK. In all cases, RCOOK can be chosen in order to introduce, in the polyesters, reactive functional groups such as unsaturated (double or triple bond) and hydroxy ones. The NMR analysis of polymers has shown that a cyclic dimer (C2) was formed in most cases. Its amount depends on the process of polymerization and on the experimental conditions. The $\overline M _{\rm n}$ of polyesters was found to be correlated with the amount of C2. The MALDI‐TOF analysis of polymers confirmed the formation of cycles and showed that both the polymerization of 2K in the presence of TBMM and that of 2a in the presence of some particular RCOOK's led to the formation of acyclic macromolecules.Expanded aromatic region of the 1H NMR spectrum of a polymer showing the six characteristic resonances H, H, H, H, H and H of the cyclic dimer C2.magnified imageExpanded aromatic region of the 1H NMR spectrum of a polymer showing the six characteristic resonances H, H, H, H, H and H of the cyclic dimer C2.
Thermoreversible Supramolecular Organization in Poly(vinylidene fluoride)–Dodecyl Benzene Sulfonic Acid Blends
Authors: Habibur Rahman M. , Malik Sudip , Nandi Arun K. 
Published: October 2003

AbstractBlends of poly(vinylidene fluoride) (PVF2) and dodecyl benzene sulfonic acid (DBSA) were found to phase separate in the melt state from hot‐stage polarizing optical microscopy and differential scanning calorimetry (DSC). Both these studies also indicated the formation of a reversible mesomorphic order in the DBSA‐rich phase of the blends. Scanning electron microscopy (SEM) showed a fibrillar network morphology of the DBSA‐rich phase. Wide‐angle X‐ray diffraction (WAXD) revealed the formation of a lamellar structure in the blends corresponding to a long period of 26 Å. The mesomorphic nature of the blends is believed to arise from the supramolecular organization of the surfactant molecules within the lamella. Thermal study indicated that the supramolecularly organized complex is the VF2 monomer unit:DBSA ≈ 4:1, and the enthalpy of complexation is ∼723 J · mol−1.SEM micrograph of a PVF2‐DBSA blend with weight fraction of DBSA (WDBSA) = 0.62.magnified imageSEM micrograph of a PVF2‐DBSA blend with weight fraction of DBSA (WDBSA) = 0.62.
Adducts of Polymeric Organolithiums with 1,1‐Diphenylethylene. Rates of Formation and Crossover to Styrene and Diene Monomers
Authors: Quirk Roderic P. , Lee Bumjae 
Published: October 2003

AbstractThe addition reactions of 1,1‐diphenylethylene (DPE) to polymeric organolithium (PLi) compounds and the crossover reactions of the resulting polymeric 1,1‐diphenylalkyllithiums with styrene, isoprene and butadiene monomers have been investigated and optimized. The addition of poly(styryl)lithium (PSLi) to one unit of DPE at 25 °C is complete in 6 and 8 h in benzene and cyclohexane, respectively. After 3 d at 25 °C, the extent of end‐capping with DPE was only 9% for poly(butadienyl)lithium and 15% for poly(isoprenyl)lithium. Addition of THF ([THF]/[PLi] = 15–40) promotes quantitative addition of poly(dienyl)lithiums to DPE within 1–4 hours at 25 °C. Crossover reactions of polymeric 1,1‐diphenylalkyllithiums (growth out) to styrene monomers are slow relative to crossover reactions to diene monomers. Crossover to diene monomers is complete within approximately 2 min at 25 °C and leads to well‐defined, narrow molecular weight distribution block copolymers ($\overline M _{\rm w} /\overline M _{\rm n}$ = 1.01 with $\overline M _{\rm n}$ (out, calc) > 2 900 g · mol−1). Crossover to styrene monomers requires 12 h and leads to broad molecular weight distributions ($\overline M _{\rm w} /\overline M _{\rm n}$ > 1.1) and inefficient crossover if $\overline M _{\rm n}$ (out; calc) < 7 000 g · mol−1 and the chain end concentration is ≤ 10−3 M. Crossover to the styrene monomer is favored by low temperatures (5 °C), high chain end concentrations, and higher molecular weights of the growing block.
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Comparative study by simulation of photovoltaic pumping systems with stationary and polar tracking arrays
Authors: Illanes R. , De Francisco A. , Torres J. L. , De Blas M. , Appelbaum J. 
Published: October 2003

AbstractUsing mathematical models for the different components of the photovoltaic pumping system: generator, inverter (if applicable), motors, pumps and piping, we have developed a computer program that, for given irradiance and temperature data, calculates the flow of water pumped at any given time. The program has been applied to study the hourly and yearly water flow pumped by a photovoltaic pumping system located in Madrid, employing centrifugal pumps powered by AC motors. The photovoltaic generator consists of, in one case, a stationary array and in the second case a polar tracking array. The hourly radiation data were estimated from the distribution of the atmospheric clearness coefficients and the monthly average daily radiation on a horizontal surface. The results of this study show that the use of a polar tracking array increases the average yearly water flow compared with the stationary array more than the corresponding increase of the incident radiation on the arrays. Copyright © 2003 John Wiley & Sons, Ltd.
Experimental analysis of battery charge regulation in photovoltaic systems
Authors: Díaz Pablo , Ángel Egido Miguel 
Published: October 2003

AbstractThe influence of charge regulation on batteries for stand‐alone photovoltaic systems is analysed in relation to two factors: battery lifetime and the daily energy service supplied. The regulation thresholds adjusted in the charge controller (for disconnection and reconnection), in overcharge and deep discharge conditions, determine the whole system operation. Laboratory testing procedures are proposed and applied to different components of the photovoltaic rural electrification market. Finally, technical recommendations for charge regulation of lead–acid batteries are presented. Copyright © 2003 John Wiley & Sons, Ltd.
Morphology‐dependent luminescence properties of poly(benzyl ether) dendrimers
Authors: Kimata Shu‐Ichi , Jiang Dong‐Lin , Aida Takuzo 
Published: October 2003

AbstractPoly(benzyl ether) dendrimers with o‐, m‐, and p‐isomers of dialkoxybenzene at their focal points [o‐, m‐, and p‐(Gn)2Ar], having generation numbers (n) of 0–3, were synthesized. 1H NMR pulse relaxation times (T1) of the exterior MeO groups of o‐ and m‐(Gn)2Ar (n = 0–3) all remained in the range of 0.92–1.43 s. In sharp contrast, an exceptionally short T1 value (0.23 s) was observed for p‐(G3)2Ar. Although their absorption spectral profiles were slightly different from one another, an essential difference was observed for their fluorescence properties. When the generation number was increased, the fluorescence efficiency of o‐(Gn)2Ar increased, but that of p‐(Gn)2Ar decreased, whereas m‐(Gn)2Ar exhibited a relatively small change in the fluorescence efficiency. Fluorescence depolarization studies showed a highly efficient intramolecular energy migration in p‐(G3)2Ar as compared with o‐(G3)2Ar and m‐(G3)2Ar. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3524–3530, 2003
Solvent‐free polycondensation of 1,3‐bis(hydroxyphenylmethyl)benzene. II. The dramatic difference in the polymerization behavior between meso and racemic isomers
Authors: Suzuki Masato , Sasaki Takeshi , Matsuura Go , Kimura Mika 
Published: October 2003

AbstractThe meso and racemic forms of 1,3‐bis(hydroxyphenylmethyl)benzene underwent solvent‐free polycondensation with the aid of an acid catalyst giving polyether. Very interestingly, the diastereoisomerism caused a considerable difference in the polymerization behavior. The meso isomer (mp = 96–98 °C) was polymerized even at 65 °C, whereas the racemic one (mp = 158–160 °C) required heating at 100 °C to undergo polymerization. However, the latter produced a much higher molecular weight than the former (30,000 vs 4000). The contamination of the meso isomer with the racemic one very sensitively reduced the polymerization temperature: the 98.5% meso monomer underwent polymerization at 50 °C. In contrast to solvent‐free polymerization, two diastereomeric monomers showed almost identical behavior in solution polymerization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3564–3571, 2003
Alternating copolymerization of carbon dioxide and epoxide by manganese porphyrin: The first example of polycarbonate synthesis from 1‐atm carbon dioxide
Authors: Sugimoto Hiroshi , Ohshima Hiromitsu , Inoue Shohei 
Published: October 2003

AbstractThe first successful example of the formation of polycarbonate from 1‐atm carbon dioxide and epoxide was demonstrated by the alternating copolymerization of carbon dioxide and epoxide with manganese porphyrin as a catalyst. The copolymerization of carbon dioxide and cyclohexene oxide with (porphinato)manganese acetate proceeded under the 1‐atm pressure of carbon dioxide to give a copolymer with an alternating sequence. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3549–3555, 2003
Synthesis of glycosaminoglycans via enzymatic polymerization
Authors: Kobayashi Shiro , Itoh Ryosuke , Morii Hidekazu , Fujikawa Shun‐Ichi , Kimura Shunsaku , Ohmae Masashi 
Published: October 2003

AbstractHyaluronic acid and chondroitin were successfully synthesized as representative molecules of glucosaminoglycans and galactosaminoglycans found in a glycosaminoglycan family via enzymatic polymerization catalyzed by testicular hyaluronidases. A newly designed N‐acetylhyalobiuronate oxazoline derivative with a β‐D‐glucuronyl‐(1→3)‐N‐acetyl‐D‐glucosamine disaccharide structure served as a transition‐state analogue substrate monomer for the enzyme, giving rise to artificial hyaluronic acid in 52% yields with a number‐average molecular weight of 1.35 × 104 through ring‐opening polyaddition in a perfect regioselective and stereoselective manner. A novel N‐acetylchondrosine oxazoline derivative with a β‐D‐glucuronyl‐(1→3)‐N‐acetyl‐D‐galactosamine disaccharide structure also acted as a transition‐state analogue substrate monomer for the enzyme, yielding artificial chondroitin in 35% yields with a number‐average molecular weight of 2.5 × 103. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3541–3548, 2003
Cofacially constrained organic semiconductors
Authors: Tovar John D. , Swager Timothy M. 
Published: October 2003

AbstractWe present the synthesis, spectroscopy, and electrochemistry of bis[oligo(thiophene)] monomers where the sterics of covalently attached subunits enforced oblique spatial orientations. The synthetic scheme applied to a variety of chromophores; standard bromination and cross‐coupling chemistry afforded bis(terthienyl)benzene systems in high yield. We prepared model systems consisting of mono(terthiophene)s to probe the effects that van der Waals contacts impose during electropolymerization and methyl‐blocked analogues to examine the electrochemical properties of derivatives that do not undergo polymerization. We discuss the extent of delocalization between chromophores as deduced from electrochemical studies and demonstrate that these materials provide viable electrochromic polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3693–3702, 2003