bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical and optical properties of CdS nanocrystalline semiconductors
Authors: Tiwari Shikha , Tiwari Sanjay 
Published: December 2005

AbstractII‐VI semiconductor nanoparticles have recently attracted a lot of attention due to the possibility of their application in various devices. In the present study, chemical method has been used in synthesis of CdS nanoparticles and thiophenol was used as capping agent. X‐ray diffraction studies of both samples were done. The dc conductivity of CdS increases at a lower rate or is approximately constant upto 500K and thereafter the conductivity increases at a rapid rate. Beyond Tc it is seen that the portion of the σdc versus 1000/T is almost a straight line showing an Arrehenious behaviour. The dielectric constant of nanoparticles of CdS is found to be larger than the corresponding values of CdS crystals. It is clearly observed that at lower wavelengths nanocrystalline samples show a blue‐shift. The three peaks of sample (S2), A, Band C can be ascribed to the transition from Cd‐O complex donor formed by adsorbed oxygen to the valance band, Cd ‐ excess acceptor and the surface states, respectively. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Toll‐like receptor 9‐mediated induction of the immunosuppressive pathway of tryptophan catabolism
Authors: Fallarino Francesca , Puccetti Paolo 
Published: December 2005

AbstractA series of recent studies, including an article in this issue of the European Journal of Immunology, have demonstrated that the administration of CpG‐rich oligodeoxynucleotides (CpG‐ODN) in experimental settings may lead to the activation of the immunosuppressive pathway of tryptophan catabolism, depending on several factors, including the route of CpG‐ODN administration. These studies call attention to the need for a careful evaluation of the modalities of inclusion of CpG‐ODN in vaccines for human use. At the same time, these studies may offer novel opportunities for use of CpG‐ODN as immunosuppressive agents and may also lead to an improved understanding of the cellular events mediated by Toll‐like receptor 9 signaling.See accompanying article: http://dx.doi.org/10.1002/eji.200535602
Chloro, Alkyl and Aryl Complexes of Rare Earth Metals Supported by Bulky Tetrasubstituted Guanidinate Ligands
Authors: Trifonov Alexander A. , Lyubov Dmitrii M. , Fedorova Elena A. , Fukin Georgy K. , Schumann Herbert , Mühle Stefan , Hummert Markus , Bochkarev Mikhail N. 
Published: December 2005

AbstractThe reactions of anhydrous LnCl3 (Ln = Y, Nd, Sm, Lu) with two equiv. of sodium N,N′‐dicyclohexyl‐N′′‐bis(trimethylsilyl)guanidinate Na[(Me3Si)2NC(NCy)2], obtained from Na[N(SiMe3)2] and the 1,3‐dicyclohexyl‐substituted carbodiimide CyN=C=NCy in THF, yield the monochloro bis(guanidinate) tetrahydrofuranate complexes [(Me3Si)2NC(NCy)2]2LnCl(THF) [Ln = Y (1), Nd (2), Sm (3) and Lu (4)]. The analogous reactions of YCl3 and LuCl3 with the lithium guanidinate [Li(Et2O)][(Me3Si)2NC(NCy)2] afford the bis(guanidinate) “ate” complexes [(Me3Si)2NC(NCy)2]2Ln(μ‐Cl)2Li(THF)2 [Ln = Y (5) and Lu (6)]. Treatment of 5 with dimethoxyethane results in the formation of [(Me3Si)2NC(NCy)2]2Y(μ‐Cl)2Li(DME) (7). The carbyl complexes [(Me3Si)2NC(NCy)2]2Y‐tBu] (8), [(Me3Si)2NC(NCy)2]2Y(μ‐Me)2Li(TMEDA) (10) and [(Me3Si)2NC(NCy)2]2YPh(THF) (13) were obtained by interaction of complex 1 with RLi (R = tBu, Me or Ph). The molecular structures of 1, 6, 7, 8 and the side product [Li(TMEDA)][(Me3Si)2NC(NCy)2] have been determined by single‐crystal X‐ray analyses. Agostic interactions between the yttrium atom and the tert‐butyl group in complex 8 in the solid state as well as in solution have been substantiated by 13C NMR spectroscopy and X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Reactivity of Carboranylacetylenes towards Cobalt Complexes
Authors: Goswami Avijit , Nie Yong , Oeser Thomas , Siebert Walter 
Published: December 2005

AbstractThe reaction of 1,6‐diiodo‐C4B2 nido‐carborane derivative 1 with RC2Li (R = Me, SPh) yields the corresponding carboranylacetylenes 2b,c. Treatment of the PPh2‐substituted nido‐carborane 3a with PhC2ZnCl in the presence of a catalytic amount of Pd(PPh3)4 leads to the known basal‐substituted nido‐carboranylacetylene 2a. The synthesis of apical‐substituted compound 4b is achieved by the substitution of 3b by a Pd0‐catalyzed Nigishi‐type cross‐coupling reaction; the basal boron atom is blocked by the n‐butyl group. The 1,3‐dicarboranyl‐substituted (η4‐cyclobutadiene)cobalt complexes 5a,c are obtained from the reactions of 2a,c with stoichiometric amounts of CpCo(C2H4)2. The 1,6‐dialkynyl carborane 6 reacts regioselectively at the basal acetylene group with a stoichiometric amount of CpCo(CO)2 to give 1,3‐dicarboranyl‐substituted (cyclobutadiene)cobalt complex 7. The dicarboranyl‐substituted (cyclopentadienone)cobalt complex 8 is formed by the reaction of compound 4b with CpCo(CO)2. The new compounds are characterized by NMR spectroscopy, mass spectrometry, and by X‐ray crystal structure analyses for 5a and 8. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
The Ligand Effect: CO Desorption from Pt/Ru Catalysts
Authors: Davies J. C. , Bonde J. , Logadóttir Á. , Nørskov J. K. , Chorkendorff I. 
Published: December 2005

AbstractDensity Functional Theory (DFT) calculations of the adsorption energy of CO, for a platinum overlayer on Ru(0001), have been performed. For all coverages a significant reduction in the binding energy of up to 0.5 eV has been observed compared to that obtained on Pt(111). In addition, a Steady‐State Isotopic Transient Kinetic Analysis (SSITKA) study has been performed to determine the desorption rate dependence on the partial pressure of CO over commercial Pt/Ru electrocatalysts. As expected, no significant difference in the rate of exchange of CO at any given pressure is observed on going from Pt to Pt/Ru electrocatalysts when the diluted gas used was argon since the CO states will be filled to the same desorption energy for the two catalysts. However on changing the diluent gas to hydrogen, a reduction in the exchange rate for CO is observed clearly reflecting the lower CO binding energy and the increased competition for sites at the surface of the catalyst. The reduction efficiency of the Pt/Ru electrocatalyst was also studied and found to be highly dependent on whether CO or hydrogen was used. These results will be discussed with reference to the anode catalysis of the Polymer Electrolyte Membrane Fuel Cell (PEMFC).
Intensity‐modulated radiation therapy in head and neck cancers: An update
Authors: Lee Nancy , Puri Dev R. , Blanco Angel I. , Chao K. S. Clifford 
Published: December 2005

AbstractIntensity‐modulated radiation therapy (IMRT), an advent of three‐dimensional conformal radiotherapy (3D CRT), has excited the profession of radiation oncology more than any other new invention since the introduction of the linear accelerator. Approximately 1000 articles have been published on this topic to date, more than 200 of which focus on head and neck cancer. IMRT is based on computer‐optimized treatment planning and a computer‐controlled treatment delivery system. The computer‐driven technology generates dose distributions that sharply conform to the tumor target while minimizing the dose delivered to the surrounding normal tissues. The high dose volume that tailors to the 3D configuration of the tumor along with the ability to spare the nearby normal tissues allows the option of tumor dose escalation.The head and neck region is an ideal target for this new technology for several reasons. First, IMRT offers the potential for improved tumor control through delivery of high doses to the target volume. Second, because of sharp dose gradients, IMRT results in the relative sparing of normal structures, such as the parotid glands, in the head and neck region. Third, organ motion is virtually absent in the head and neck region so, with proper immobilization, treatment can be accurately delivered. Although this is a relatively new technology, single‐institution retrospective studies show better dosimetric profiles compared with conventional radiation techniques, as well as excellent clinical results. Salivary gland sparing using IMRT has also resulted in reduced incidence and severity of xerostomia, and this has been tested in a randomized trial against conventional radiotherapy for early‐stage nasopharyngeal cancer. The results do confirm that IMRT does decrease xerostomia compared with conventional radiotherapy. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX, 2005
Ventral hippocampal muscimol disrupts context‐specific fear memory retrieval after extinction in rats
Authors: Hobin Jennifer A. , Ji Jinzhao , Maren Stephen 
Published: December 2005

AbstractResearch aimed at understanding Pavlovian fear memory extinction has yielded considerable insight into the conditions under which fear memories may become inhibited. After extinction, Pavlovian fear memory retrieval is context‐specific. Fear memories are not expressed in the extinction context, but they are expressed in every other context. Research indicates that the dorsal hippocampus mediates the context‐specific expression of fear memory, but the role of the ventral hippocampus in mediating this process is unknown. Insofar as the ventral hippocampus is involved in the acquisition and expression of both context and tone fear, we asked whether GABA systems in the ventral hippocampus mediate context‐specific fear memory retrieval after extinction. Experiment 1 showed that ventral hippocampal inactivation with muscimol disrupted context‐specific fear memory retrieval. Experiment 2 showed that rats infused with muscimol can discriminate a context in which they were shocked from a neutral context. Nonetheless, they do appear to have a mild impairment in this task. Experiment 3 showed that ventral hippocampal muscimol did not disrupt locomotor activity, but did result in a slight increase in freezing and grooming, an effect that cannot explain the context‐specific retrieval deficit demonstrated in experiment 1. These data are consistent with a role for the ventral hippocampus in mediating context‐specific fear memory retrieval. © 2005 Wiley‐Liss, Inc.
Characterization of a faster resorbing polymer after real time aging
Authors: McManus Anastasia J. , Moser Rodney C. , Thomas Kevin A. 
Published: December 2005

AbstractThis study evaluated the in vitro strength retention and polymer characteristics of specimens made from commercially available 85:15 poly(D,L‐lactide‐co‐glycolide). Test samples included dogbone tensile specimens with a nominal thickness of either 0.75 and 1.0 mm, which were machined from compression‐molded sheets, and screws with a major diameter of 2.71 mm and minor diameter of 2.14 mm, which were manufactured by injection molding. All samples were sterilized by e‐beam irradiation prior to in vitro aging following a standard methodology. Mechanical testing and polymer analysis were performed at time zero and weekly up to 15 weeks of real time aging. The time zero maximum tensile strength of the 0.75 mm dogbone specimens averaged 55.86 ± 0.72 MPa. The 1.0‐mm dogbone specimens tested at time zero had an average maximum tensile strength of 34.55 ± 0.36 MPa. The 0.75‐mm and 1.0‐mm thick dogbone specimens exhibited a controlled decrease in their tensile strength. The initial shear strength of the injection‐molded screws was 32.86 ± 4.15 MPa. After 3 weeks of real time in vitro aging, the screws maintained approximately 70% of their initial (time zero) strength. The inherent viscosity and molecular weight (Mw) at time zero averaged approximately 0.9 dL/g and 98,000 g/mol respectively, and decreased at similar rates for both dogbones and screws. These results demonstrate a controlled, rapid degradation in the mechanical properties of 85:15 poly(D,L‐lactide‐co‐glycolide) material, with sufficient strength for pediatric craniofacial applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Effects of applied voltages on hydroxyapatite coating of titanium by electrophoretic deposition
Authors: Meng Xianwei , Kwon Tae‐Yub , Yang Yunzhi , Ong Joo L. , Kim Kyo‐Han 
Published: December 2005

AbstractHydroxyapatite (HA) coatings were deposited on titanium substrates by electrophoretic deposition (EPD) at constant voltage and dynamic voltage, respectively. Various surface morphologies were observed under different type of voltages. Under a constant voltage of 20 V, a dense HA coating could be prepared. Under a constant voltage of 200 V, big HA particles were deposited and the coating was porous. Under a dynamic voltage, a continuous gradient HA coating could be obtained. HA coatings were characterized with a field emission‐scanning electron microscopy (FE‐SEM) and an X‐ray diffraction (XRD). XRD indicated no significant HA decomposition when the coatings were sintered for 2 h at 800°C. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Using internal and collective variables in Monte Carlo simulations of nucleic acid structures: Chain breakage/closure algorithm and associated Jacobians
Authors: Sklenar Heinz , Wüstner Daniel , Rohs Remo 
Published: December 2005

AbstractThis article describes a method for solving the geometric closure problem for simplified models of nucleic acid structures by using the constant bond lengths approximation. The resulting chain breakage/closure equations, formulated in the space of variable torsion and bond angles, are easy to solve, and have only two solutions. The analytical simplicity is in contrast with the high complexity of the closure problem in the torsion angle space with at most 16 solutions, which has been dealt with by several authors and was solved analytically by Wu and Deem (J. Chem. Phys. 1999, 111, 6625). The discussion on the choice of variables and associated Jacobians is focussed on the question of how conformational equilibration is affected in Monte Carlo simulations of molecular systems. In addition to the closure of the phosphate backbone, it is necessary to also solve the closure problem for the five‐membered flexible furanose sugar ring. Explicit closure equations and the resulting Jacobians are given both for the complete four‐variable model of the furanose ring and simulations in the phase‐amplitude space of the five‐membered ring, which are based on the approximate two‐variable model of furanose introduced by Gabb et al. (J. Comput. Chem. 1995, 16, 667). The suggested closure algorithm can be combined with collective variables defined by translations and rotations of the monomeric nucleotide units. In comparison with simple internal coordinate moves, the resulting concerted moves describe local structural changes that have high acceptance rates and enable fast conformational equilibration. Appropriate molecular models are put forward for prospective Monte Carlo simulations of nucleic acids, but can be easily adapted to other biomolecular systems, such as proteins and lipid structures in biological membranes. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 309–315, 2006
On the acyclic choosability of graphs
Authors: Montassier Mickaël , Ochem Pascal , Raspaud André 
Published: December 2005

AbstractA proper vertex coloring of a graph G =  (V,E) is acyclic if G contains no bicolored cycle. A graph G is L‐list colorable if for a given list assignment L = {L(v): v ∈ V}, there exists a proper coloring c of G such that c (v) ∈ L(v) for all v ∈ V. If G is L‐list colorable for every list assignment with |L (v)| ≥ k for all v ∈ V, then G is said k‐choosable. A graph is said to be acyclically k‐choosable if the obtained coloring is acyclic. In this paper, we study the links between acyclic k‐choosability of G and Mad(G) defined as the maximum average degree of the subgraphs of G and give some observations about the relationship between acyclic coloring, choosability, and acyclic choosability. © 2005 Wiley Periodicals, Inc. J Graph Theory 51: 281–300, 2006
Palaeoindian occupation of the Atacama Desert, northern Chile
Authors: Grosjean Martin , Núñez Lautaro , Cartajena Isabel 
Published: December 2005

AbstractPalaeoindian occupation of the Atacama Desert in northern Chile has been found between 12 600 and 10 200 cal. yr BP. The new site at Salar Punta Negra (24°28′S/60°53′W/2976 m) includes about 1000 classifiable, mostly unifacial artefacts and, uniquely, three different diagnostic types of early projectile points. Two of the Lateglacial/early Holocene projectile types have wide distribution and are known from different geographical areas in South America: the Palaeoindian ‘Fell’ fish‐tail point mainly from the southern cone of South America, and the triangular ‘Tuina’ points typical of the Puna of the south‐central Andes in northern Chile and northwestern Argentina. In addition, we found a third type, a stemmed point typical for the Salar Punta Negra. Filling a large geographical gap of ‘Fell’ occupation, the site at Salar Punta Negra provides evidence for generally much higher mobility and diversity of early cultures, and supports an Andean‐Pacific route for early human exploration of South America to the south through the desert at intermediate altitudes. Contemporaneous high‐amplitude climatic changes were fundamental preconditions to provide adequate environments and habitats, and to make Palaeoindian hunting‐gathering occupation possible in the Atacama Desert. Copyright © 2005 John Wiley & Sons, Ltd.
A 17 000‐year history of Andean climate and vegetation change from Laguna de Chochos, Peru
Authors: Bush Mark B. , Hansen Barbara C. S. , Rodbell Donald T. , Seltzer Geoffrey O. , Young Kenneth R. , León Blanca , Abbott Mark B. , Silman Miles R. , Gosling William D. 
Published: December 2005

AbstractThe manifestation of major climatic events such as the timing of deglaciation and whether, or not, the Younger Dryas affected Andean systems has garnered considerable recent attention. Even the Holocene is rapidly emerging as a time of considerable interest in Neotropical palaeoclimatology and palaeoecology. The Holocene of the Neotropics is now revealed as a time of some temperature change with precipitation:evaporation ratios fluctuating markedly. Major changes in lake level, ice‐accumulation, and vegetation are indicative of changes both in precipitation and temperature regimes. Although global‐scale forcing mechanisms may underlie some of these changes, e.g. the precessional rhythm, other variability appears to be localised. In a record from near the upper forest limit of the eastern Peruvian Andes, pollen, charcoal, and sedimentary data suggest that the deglaciational period from ca. 17 000 to ca. 11 500 cal. yr BP was a period of rapid climatic oscillations, set against an overall trend of warming. A warm‐dry event is evident between ca. 9500 and ca. 7300 cal. yr BP, and comparisons with other regional archives suggest that it was regional in scale. A ca. 1500‐yr periodicity in the magnetic susceptibility data is evident between 12 000 and 6000 cal. yr BP, reaching a peak intensity during the dry event. A weaker oscillation with a 500–600‐yr periodicity is present throughout much of the Holocene. The uppermost sample of the pollen analysis reveals deforestation as modern human land use simplified the landscape. Copyright © 2005 John Wiley & Sons, Ltd.
Holocene hydrologic variation at Lake Titicaca, Bolivia/Peru, and its relationship to North Atlantic climate variation
Authors: Baker P. A. , Fritz S. C. , Garland J. , Ekdahl E. 
Published: December 2005

AbstractA growing number of sites in the Northern Hemisphere show centennial‐ to millennial‐scale climate variation that has been correlated with change in solar variability or with change in North Atlantic circulation. However, it is unclear how (or whether) these oscillations in the climate system are manifest in the Southern Hemisphere because of a lack of sites with suitably high sampling resolution. In this paper, we reconstruct the lake‐level history of Lake Titicaca, using the carbon isotopic content of sedimentary organic matter, to evaluate centennial‐ to millennial‐scale precipitation variation and its phasing relative to sites in the Northern Hemisphere. The pattern and timing of lake‐level change in Lake Titicaca is similar to the ice‐rafted debris record of Holocene Bond events, demonstrating a possible coupling between precipitation variation on the Altiplano and North Atlantic sea‐surface temperatures (SSTs). The cold periods of the Holocene Bond events correspond with periods of increased precipitation on the Altiplano. Holocene precipitation variability on the Altiplano is anti‐phased with respect to precipitation in the Northern Hemisphere monsoon region. More generally, the tropical Andes underwent large changes in precipitation on centennial‐to‐millennial timescales during the Holocene. Copyright © 2005 John Wiley & Sons, Ltd.
Palaeohydrology of Laguna de Tagua Tagua (34° 30′ S) and moisture fluctuations in Central Chile for the last 46 000 yr
Authors: Valero‐Garcés Blas L. , Jenny Bettina , Rondanelli Mauricio , Delgado‐Huertas Antonio , Burns Stephen J. , Veit Heinz , Moreno Ana 
Published: December 2005

AbstractCentral Chile (32–35° S) lies at the northern border of the strong influence of the westerly circulation belt and thus exhibits a steep rainfall gradient. A new core from Laguna de Tagua Tagua (34° 30′ S) provides a sedimentologic, geochemical and palynological record of regional hydrologic balance for the last 46 000 cal. yr BP. According to our age model, relatively humid conditions occurred during glacial times before 43 500 cal. yr BP and from 40 000 to 21 500 cal. yr BP. Reduced moisture conditions and likely lower temperatures occurred from 42 400–40 100 cal. yr BP. Higher lake levels, and pollen assemblages with Valdivian rainforest taxa, imply much higher precipitation during glacial times (40 100–21 000 cal. yr BP) compared to today and, therefore, enhanced westerly activity in northern Central Chile. Afterwards, the general decrease in moisture was punctuated by two abrupt arid periods at 21 000–19 500 cal. yr BP and 17 000–15 000 cal. yr BP, and two more humid intervals: 19 500–17 000 (almost coincident with the global Last Glacial Maximum, LGM) and 13 500–11 500 cal. yr BP. The early and mid‐Holocene were the most arid periods in Central Chile for the studied time interval. Millennial‐scale palaeohydrological reconstructions from Tagua Tagua are consistent with regional climatic records. Copyright © 2005 John Wiley & Sons, Ltd.
Perception of casinos as disruptive influences in USA communities
Authors: Stitt B. Grant , Nichols Mark , Giacopassi David 
Published: December 2005

AbstractCasino gambling has been adopted by many communities as a means of increasing tourism and tax revenue. Casinos, however, are a controversial tourism development strategy. The present paper uses social exchange theory to examine the effects of casinos in eight communities that have had casino gambling for at least 4 years. Residents were asked to comment on possible disruptive influences that could be tied to casino presence. These disruptive influences include not only serious crimes but also publicly visible nuisance crimes such as drinking in public, vandalism and prostitution. Also assessed are such factors as perceived increases or decreases in physical decay of the communities, presence of litter on streets and sidewalks, homelessness, traffic congestion, and prevalence of divorce, suicide and bankruptcy. The majority of respondents do not perceive significant changes in most disruptive influences. However, findings vary significantly by community, by type of disruptive influence, and by whether the respondent was a gambler or non‐gambler. The results of this analysis should be of interest to communities considering casino gambling as a new tourist attraction. Copyright © 2005 John Wiley & Sons, Ltd.