bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tandem mass spectrometry of amidated peptides
Authors: Mouls Laetitia , Subra Gilles , Aubagnac Jean‐Louis , Martinez Jean , Enjalbal Christine 
Published: October 2006

AbstractThe behavior of C‐terminal amidated and carboxylated peptides upon low‐energy collision‐induced dissociation (CID) was investigated. Two sets of 76 sequences of variable amino acid compositions and lengths were synthesized as model compounds. In most cases, C‐terminal amidated peptides were found to produce, upon CID, an abundant loss of ammonia from the protonated molecules. To validate such MS/MS signatures, the studied peptides contained amino acids that can potentially release ammonia from their side chains, such as asparagine, glutamine, tryptophan, lysine and arginine. Arginine, and to a lesser extent lysine, was shown to induce a competitive fragmentation leading to the loss of ammonia from their side chains, thus interfering with the targeted backbone neutral release. However, when arginine or lysine was located at the C‐terminal position mimicking a tryptic digest, losses of ammonia from the arginine side chain and from the peptide backbone were completely suppressed. Such results were discussed in the frame of peptidomic or proteomic studies in an attempt to reveal the presence of C‐terminal amidated peptides or proteins. Copyright © 2006 John Wiley & Sons, Ltd.
Morphological heterogeneity of CA1 pyramidal neurons in response to ischemia
Authors: Ruan Yi‐Wen , Zou Bende , Fan Yuan , Li Yan , Lin Nan , Zhang Yuchun , Xu Zao C. 
Published: October 2006

AbstractWe have found, based on the electrophysiological properties, two subtypes of CA1 pyramidal neurons in the CA1 region of the normal hippocampus, late postsynaptic potential (L‐PSP) neurons and non‐L‐PSP neurons. In addition, our previous study has shown that the electrophysiological properties of these two subtypes of pyramidal neurons were differentially modified after ischemia. In the present study, we hypothesized that ischemia might also induce different morphological alterations in these two subtypes of neuron. To test the hypothesis, we compared the changes in the dendritic arborization and soma volume of these two subtypes of neurons in rats subjected to transient global ischemia. We found a significant decrease in the basal dendritic length of L‐PSP neurons at 12 hr after reperfusion, resulting mainly from a significant decrease in the dendrite terminal length. The apical dendritic length of L‐PSP neurons markedly increased at 24 hr after ischemia, resulting mainly from an increase in the number of branching arbors in the middle part of the apical dendritic trees. The soma size of L‐PSP neurons was significantly reduced at 12 hr, but they became slightly larger at 24 hr and 48 hr after reperfusion. In contrast to L‐PSP neurons, non‐L‐PSP neurons showed slight modifications in the dendritic arborization but had persistent swelling of their soma after ischemia. These results indicate that pathological changes in these two subtypes of neurons are different after ischemia. © 2006 Wiley‐Liss, Inc.
Poly(propylene glycol)‐Grafted Multi‐Walled Carbon Nanotube Polyurethane
Authors: Xia Hesheng , Song Mo , Jin Jie , Chen Lei 
Published: October 2006

AbstractSummary: Poly(propylene glycol)‐grafted MWNT polyurethane was synthesized based on the hydroxyl functionalized MWNTs through a two‐step reaction. The grafted MWNTs can improve the rheological behavior of the polyol/MWNT dispersion, and have a better reinforcing effect on the mechanical properties of polyurethane and lower hysteresis compared to the raw carbon nanotubes. A comparison for energy dissipation in PU/carbon nanotube and exfoliated PU/organoclay nanocomposites was given. The energy dissipated in the grafted MWNT composite system is lower.Dispersion stability of carbon nanotubes in polyether polyol after 40 min centrifugation (A: MWNT, B: MWNT‐OH, C: MWNT‐graft‐PU).magnified imageDispersion stability of carbon nanotubes in polyether polyol after 40 min centrifugation (A: MWNT, B: MWNT‐OH, C: MWNT‐graft‐PU).
9.4T human MRI: Preliminary results
Authors: Vaughan Thomas , DelaBarre Lance , Snyder Carl , Tian Jinfeng , Akgun Can , Shrivastava Devashish , Liu Wanzahn , Olson Chris , Adriany Gregor , Strupp John , Andersen Peter , Gopinath Anand , van de Moortele Pierre‐Francois , Garwood Michael , Ugurbil Kamil 
Published: October 2006

AbstractThis work reports the preliminary results of the first human images at the new high‐field benchmark of 9.4T. A 65‐cm‐diameter bore magnet was used together with an asymmetric 40‐cm‐diameter head gradient and shim set. A multichannel transmission line (transverse electromagnetic (TEM)) head coil was driven by a programmable parallel transceiver to control the relative phase and magnitude of each channel independently. These new RF field control methods facilitated compensation for RF artifacts attributed to destructive interference patterns, in order to achieve homogeneous 9.4T head images or localize anatomic targets. Prior to FDA investigational device exemptions (IDEs) and internal review board (IRB)‐approved human studies, preliminary RF safety studies were performed on porcine models. These data are reported together with exit interview results from the first 44 human volunteers. Although several points for improvement are discussed, the preliminary results demonstrate the feasibility of safe and successful human imaging at 9.4T. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Discrimination between benign and malignant prostate tissue using chromatin texture analysis in 3‐D by confocal laser scanning microscopy
Authors: Huisman André , Ploeger Lennert S. , Dullens Hub F.J. , Jonges Trudy N. , Belien Jeroen A.M. , Meijer Gerrit A. , Poulin Neal , Grizzle William E. , van Diest Paul J. 
Published: October 2006

AbstractBACKGROUNDAnalysis of chromatin texture may improve both the diagnosis and the assessment of the prognosis of prostate cancer. Confocal laser scanning microscopy (CLSM) allows performing measurements in nuclei reconstructed in 3‐D. The aim of this study was to evaluate the clinical usefulness of 3‐D texture analysis of prostate tissue.METHODSImage stacks of eight prostate cancer sections were obtained by CLSM of both benign and malignant areas. Texture feature values were computed for individual nuclei. The discriminative power of the texture features was established by receiver operating characteristic (ROC) analysis and linear discriminant analysis (LDA).RESULTSTexture features were identified that could discriminate between benign and malignant nuclei. LDA correctly classified 89% of the nuclei of the pooled set of benign and malignant nuclei.CONCLUSIONS3‐D nuclear texture features allow discrimination of most benign and malignant prostate nuclei. We estimate that the classification rates can be increased by improving the image quality. Prostate 67:248–254, 2007. © 2006 Wiley‐Liss, Inc.
Morphology dependence of excitonic energy transfer in light‐ harvesting dendrimers having benzyl ether‐type peripheries
Authors: Akai I. , Kato T. , Kanemoto K. , Karasawa T. , Ohashi M. , Shinoda S. , Tsukube H. 
Published: October 2006

AbstractMorphology dependence of excitonic energy transfer in light‐harvesting dendrimers (4thm Q: m = 1, 3, and 4) with fourth branching generation is investigated from the measurements of photoluminescence (PL) spectra and the 1H‐NMR spin‐spin relaxation time (T 2). In these dendrimers, intense PL bands from the core appear for the photo‐excitation at the light‐harvesting peripheries due to the highly efficient excitonic energy transfer from the peripheries to the core. However, with the increase in the number of periphery‐subunits m, the quantum efficiency of the excitonic energy‐transfer becomes lower, and the T 2 of the exterior methoxy‐groups in the outer peripheries becomes short. These results suggest that the congestion among the aromatic rings in the outer peripheries increases anharmonicity of torsional vibrations in the peripheries, and the exciton transfer from the peripheries is strongly disturbed by dissipation processes due to the anharmonicity of the torsional vibration. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Role of Self Trapped Excitons in the scintillation process of cerium doped LaBr3
Authors: Bizarri G. , Dorenbos P. 
Published: October 2006

AbstractThe mathematical connection between the process of scintillation in cerium doped LaBr3 and the role of self trapped excitons is established. A set of kinetics equations, solved numerically, is successfully applied to describe the temperature dependence of gamma ray excited scintillation decay curves and light output as function of cerium concentration. A fit of this model coupled to experimental data provides detailed information on the STE to cerium energy transfer mechanism. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton diamagnetic shift in realistic quantum wells
Authors: Grochol M. , Grosse F. , Zimmermann R. 
Published: October 2006

AbstractExciton absorption spectra, diamagnetic shifts and localization of wave functions in realistic AlGaAs quantum wells with disorder are investigated. Two effective electron masses are chosen, bulk and enhanced due to confinement, in order to show the mass influence on the exciton properties. Whereas the absorption spectra and the localization of the wave function are modified only slightly, the diamagnetic shift turns out to be very sensitive. It is also shown that the average diamagnetic shift increases with the exciton energy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diabatic theory of the dynamical structural change triggered by injection of photoexcited states
Authors: Ishida Kunio 
Published: October 2006

AbstractWe study the coherent dynamics of the initial processes of structural change in strongly interacting electronphonon systems triggered by photoexcitation. We employ a model of localized electrons coupled with a single phonon mode, which is fully quantized in order to calculate the dynamics of consecutive switching of potential surfaces. We found that the interplay of the interaction between vibrational degrees of freedom and the Coulomb interaction between electrons is the key to understand the domain growth particularly in higher dimensional systems, which means that the symmetrical properties of the molecular orbitals are reflected in the pattern formation dynamics of the domain growth observed in photoinduced phase transition. We also found that the interference between growing domains affects on there dynamical properties and hence can be detected by accurate measurement. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum confinement effects on electron spin g‐factor in semiconductor quantum well structures
Authors: Ito Tetsu , Shichi Wataru , Morisada Shinsuke , Ichida Masao , Gotoh Hideki , Kamada Hidehiko , Ando Hiroaki 
Published: October 2006

AbstractThe effects of quantum confinement on electron spin g‐factor have been investigated in lattice‐matched GaAs/AlGaAs quantum wells (QWs) and strained InGaAs/GaAs QWs. We demonstrate how the spin precession frequency changes depending on the GaAs well width and the indium fraction in InxGa1–xAs well by time‐resolved photoluminescence measurements under a high magnetic field. The g‐factor values obtained by the spin precession measurements are compared with precise calculation method proposed by Ivchenko. The calculated results agree with our experimental results in lattice matched QWs. In addition to this calculation, we have examined a simplified k·p perturbation calculation. It is found that the k·p calculation exhibits good agreement with the experimental trends both in the unstrained and strained QW systems. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of CdTe nanoparticles fabricated by pulsed electron deposition technique at different ablation parameters
Authors: Jackson E. , Aga R. , Steigerwald A. , Ueda A. , Coffey D. , Allard L. , Pan Z. , Collins W. E. , Mu R. 
Published: October 2006

AbstractCadmium Telluride (CdTe) is a front‐runner photovoltaic (PV) material because it has already attained efficiencies above 16%. The fabrication of CdTe nanoparticles has aroused considerable interest because of their potential application as active layer in organic/inorganic hybrid solar cells. They can also be used for sensitisation of wide band gap semiconductors. In this work, we explore pulsed electron beam deposition (PED) technique to fabricate CdTe nanoparticles. Two ablation parameters, namely background gas pressure and electron energy, were varied to investigate their effects on the nanoparticle formation. Optical transmission measurements and SEM indicate that we have deposited CdTe nanocrystalline films exhibiting quantum confinement effects. From AFM, these films are as smooth as the Si substrate. In addition to the smooth film, larger nanoparticles with diameters varying from 40 nm to 500 nm were also deposited on the substrate. They contribute to the absorption onset at the bulk band gap energy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of terahertz pump‐probe spectroscopy in pseudo‐one‐dimensional halogen‐bridged Ni complex
Authors: Nakajima Makoto , Seki Takashi , Takahashi Youtarou , Kitagawa Hiroshi , Suemoto Tohru 
Published: October 2006

AbstractOptical‐pump terahertz‐probe measurements under high intensity excitation were performed using an amplified Ti:sapphire pulse laser in pseudo‐one‐dimensional halogen‐bridged Ni complex at room temperature. After photoexcitation, the transmittance decreases rapidly and then it recovers with the time constant of 1.0 ps to the quasi‐stable state. This rapid response is attributed to the free carrier originated from the charge transfer transition between Ni and Br atoms. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reactions of guanine with methyl chloride and methyl bromide: O6‐methylation versus charge transfer complex formation
Authors: Shukla P. K. , Mishra P. C. , Suhai S. 
Published: October 2006

AbstractDensity functional theory (DFT) at the B3LYP/6‐31+G* and B3LYP/AUG‐cc‐pVDZ levels was employed to study O6‐methylation of guanine due to its reactions with methyl chloride and methyl bromide and to obtain explanation as to why the methyl halides cause genotoxicity and possess mutagenic and carcinogenic properties. Geometries of the various isolated species involved in the reactions, reactant complexes (RCs), and product complexes (PCs) were optimized in gas phase. Transition states connecting the reactant complexes with the product complexes were also optimized in gas phase at the same levels of theory. The reactant complexes, product complexes, and transition states were solvated in aqueous media using the polarizable continuum model (PCM) of the self‐consistent reaction field theory. Zero‐point energy (ZPE) correction to total energy and the corresponding thermal energy correction to enthalpy were made in each case. The reactant complexes of the keto form of guanine with methyl chloride and methyl bromide in water are appreciably more stable than the corresponding complexes involving the enol form of guanine. The nature of binding in the product complexes was found to be of the charge transfer type (O6mG+ · X−, XCl, Br). Binding of HCl, HBr, and H2O molecules to the PCs obtained with the keto form of guanine did not alter the positions of the halide anions in the PCs, and the charge transfer character of the PCs was also not modified due to this binding. Further, the complexes obtained due to the binding of HCl, HBr, and H2O molecules to the PCs had greater stability than the isolated PCs. The reaction barriers involved in the formation of PCs were found to be quite high (∼50 kcal/mol). Mechanisms of genotoxicity, mutagenesis and carcinogenesis caused by the methyl halides appear to involve charge transfer‐type complex formation. Thus the mechanisms of these processes involving the methyl halides appear to be quite different from those that involve the other strongly carcinogenic methylating agents. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Homologous chromosome pairing in Schizosaccharomyces pombe
Authors: Wells Jennifer L. , Pryce David W. , McFarlane Ramsay J. 
Published: October 2006

AbstractHomologous chromosome pairing is a central feature of meiosis I, contributing to the correct segregation of chromosomes during meiosis. The fission yeast, Schizosaccharomyces pombe, has been widely used to study meiotic chromosome dynamics, partly because studies in this yeast are simplified due to the lack of post‐pairing synaptic structures. Chromosome pairing in Sz. pombe occurs differentially throughout the genome. Telomeres cluster at the spindle pole body (SPB) at the onset of meiosis, imposing a spatial restriction on pairing events. Subsequently, centromeres dissociate from the SPB and pair in a recombination‐ and heterochromatin (Swi6)‐independent fashion. Pairing of telomere distal regions occurs during meiotic prophase, concomitant with a dynamic association/dissociation of homologous regions, with interhomologue associations becoming increasingly stable. The stabilization of paired regions is enhanced by factors required for the initiation of meiotic recombination, suggesting that recombination stabilizes paired regions. However, substantial pairing is initiated in the absence of recombination; this is dependent upon another factor, the conserved Meu13 protein, demonstrating that recombination is not required for initial pairing interactions. During meiotic prophase Sz. pombe exhibits a pronounced dynein‐dependent nuclear oscillation, which drives the pairing of centromeric and interstitial regions. Dynein is also required for the significant levels of achiasmate reductional segregation observed in Sz. pombe, possibly implicating the centromere‐associated pairing with achiasmate homologue segregation. Whilst Sz. pombe does not form discernable synaptic structures continuously along the meiotic chromosomes, it does form proteinacious, meiosis‐specific, linear structures (linear elements). However, the role, if any, of these structures in mediating homologue pairing is unknown. Copyright © 2006 John Wiley & Sons, Ltd.
Misconceptions about parsimony analysis of endemicity
Authors: Nihei Silvio Shigueo 
Published: October 2006

AbstractParsimony analysis of endemicity (PAE) has been widely criticized in the recent literature based on methodology rather than on theory. Here I argue that most of the criticisms of PAE result from confusion between thedynamicandstaticapproaches of PAE, by both users and critics of the method. Originally, PAE (the dynamic approach) was proposed primarily for historical comparisons of biotic distributions based on geological and stratigraphical information; that is, the stratigraphical record of the biota within two or more horizons was used to evaluate changes (layer by layer) in their distributional patterns. This led to an analysis of the biota throughout space and through time. On the other hand, the static approach excluded the temporal component and based the analysis on a single geological horizon. Most problems exemplified and discussed in the literature refer to the static approach. In addition to this defence of the original PAE, I present some new criticisms regarding the application of PAE using artificially delimited areas (for example areas defined by geopolitical boundaries), which may lead to incorrect interpretations. Recently, several variations of static PAE have appeared: some designed to accommodate ecological data (e.g. parsimony analysis of distributions – PAD); others that incorporate phylogenetic content (e.g. cladistic analysis of distributions and endemism – CADE); and some that have been integrated with other historical methods (e.g. panbiogeography) in order to detect and evaluate hypotheses of biogeographical homologies. Biogeographers, both ecological and historical, should be aware of the problems and limitations of both dynamic and static PAE and evaluate new variations of PAE (PAD, CADE, etc.). Finally, I argue in favour of an independent and pluralist discipline of biogeography that treats biogeography as related to systematics but not dependent on it, as some scholars have assumed.
Seasonal variations in maternal mortality in Maputo, Mozambique: the role of malaria
Authors: Romagosa Cleofé , Ordi Jaume , Saute Francisco , Quintó Llorenç , Machungo Fernanda , Ismail Mamudo R. , Carrilho Carla , Osman Nafissa , Alonso Pedro L. , Menendez Clara 
Published: October 2006

SummaryObjective  To evaluate the impact of malaria on maternal death through the analysis of the seasonal variations of crude and malaria‐specific maternal mortality rates.Methods  All maternal deaths and live births occurring at Maputo Central Hospital, located in an urban area, between January 2001 and December 2003, were retrospectively recorded. Clinical diagnoses of the causes of death and period of the year were analysed.Results  Two hundred and seventy‐eight deaths were recorded. The overall crude maternal mortality rate was 995/100 000 live births. Malaria was the most frequent cause of maternal death, accounting for 23%. Crude and malaria‐specific maternal mortality rates showed a similar pattern of seasonal variation, with peaks at the beginning and the end of the malaria transmission season. The malaria‐specific maternal mortality rate was significantly higher during the rainy seasons (rate ratio 1.919; 95% CI 1.061, 3.470; P = 0.031).Conclusions  Malaria may contribute to maternal mortality in highly endemic countries in sub‐Saharan Africa, at least in urban areas. Efforts to improve malaria control in pregnancy may have an impact on maternal mortality in sub‐Saharan Africa.
Traditional practices and exposure to bodily fluids in Lusaka, Zambia
Authors: Wojcicki Janet M. , Kankasa Chipepo , Mitchell Charles , Wood Charles 
Published: October 2006

SummaryObjectives  To ascertain if there are specific sociocultural and behavioural practices associated with the exposure to saliva, semen and vaginal fluids, particularly through child‐rearing practices and the use of traditional medicine in Lusaka, Zambia.Methods  We conducted 11 focus group discussions with men and women from diverse ethnic and socioeconomic backgrounds (n = 105) in Lusaka, Zambia in March 2004. We also conducted a brief sociodemographic survey of all focus group participants.Results  Discussions indicated that saliva was used while engaging in home health care practices associated with childcare and the use of traditional medicine. Additionally, semen and vaginal fluids may be used in rituals associated with childcare and health care for children. Our survey indicated that the use of traditional medicine is associated with lower socioeconomic status.Conclusions  Population‐based studies are needed to evaluate the relationship between traditional behavioural and sociocultural practices, which involve exchange of saliva and other bodily fluids and risk of infectious disease.
Assessing Attachment Security at Age Three: Q‐sort Home Observations and the MacArthur Strange Situation Adaptation
Authors: Posada German 
Published: October 2006

AbstractThe construction of developmentally appropriate and valid assessments is central to the study of attachment relationships beyond infancy. A common procedure has been that of validating new measures for older children against strange situation classifications obtained in infancy. Although reasonable, a key criterion against which to validate new measures should include concurrent secure base behavior in naturalistic settings. The purpose of this study was to investigate whether three‐year‐olds' (N = 45) ability to use their mother as a secure base at home was related to their strange situation classifications when using the MacArthur classification system. Behavior in the strange situation was coded by two experts, and independent observers described secure base behavior at home with the attachment Q‐Set. Results indicated that strange situation classifications were not related to either global q‐set security scores or specific scale scores that reflect the quality of child–mother interactions at home.