bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlled Hydrothermal Synthesis and Structural Characterization of a Nickel Selenide Series
Authors: Zhuang Zhongbin , Peng Qing , Zhuang Jing , Wang Xun , Li Yadong
Published: October 2005

A series of nickel selenides (NiSe2 microcrystals, Ni1−xSe and Ni3Se2 microspheres) has been successfully synthesized through a convenient, low‐temperature hydrothermal method. A good nucleation and growth environment has been created by forming a uniform and transparent solution reaction system. The compositions (including the x value of Ni1−xSe), phase structures, as well as the morphologies of nickel selenides, can be controlled by adjusting the Ni/Se ratio of the raw materials, the pH, the reaction temperatures and times, and so forth. The newly produced Se microspheres in the system have been used as both reactant and in situ template to the Ni1−xSe microspheres. It is found that Ni1−xSe microspheres act as the intermediate precursor during the formation of Ni3Se2 microspheres. Under certain conditions, hexagonal NiSe microspheres can be converted into rhombohedral NiSe nanowires in solution. The formation mechanisms of a series of nickel selenides has been investigated in detail by means of X‐ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. This work has provided a general, simple, and effective method to control the composition, phase structure, and morphology of metal selenides in aqueous solution, which will be important for inorganic synthesis methodology and further applications of selenides.
DFT‐HSAB Prediction of Regioselectivity in 1,3‐Dipolar Cycloadditions: Behavior of (4‐Substituted)benzonitrile Oxides towards Methyl Propiolate
Authors: Ponti Alessandro , Molteni Giorgio
Published: October 2005

The regioselectivity of 1,3‐dipolar cycloadditions between (4‐substituted)benzonitrile oxides and methyl propiolate cannot be rationalized on the basis of the electron demand of the reactants or frontier molecular‐orbital theory. To this problem, we have applied a quantitative formulation of the hard–soft acid–base principle developed within the density functional theory. Global and local reactivity indices were computed at B3LYP/6‐311+G(d,p) level. The details of charge transfer upon the reactive encounter have been elucidated, and the computed regioselectivity has been shown to be in good agreement with experimental data.
Spiral galaxies as enantiomers: Chirality, an underlying feature in chemistry and astrophysics
Authors: Capozziello Salvatore , Lattanzi Alessandra
Published: October 2005

Spiral galaxies are axisymmetric objects showing 2D chirality when projected onto a plane. Features in common with tetrahedral molecules are pointed out, in particular the existence of a preferred chiral modality for genetic galaxies as in amino acids and sugars. Environmental effects can influence the intrinsic chirality of originally isolated stellar systems so that a progressive loss of chirality is recognized in the Hubble morphological sequence of galaxies. © 2005 Wiley‐Liss, Inc. Chirality
σ–π Energy Separation in Homodesmotic Reactions
Authors: Hohlneicher Georg , Packschies Lars , Weber Johannes
Published: October 2005

A well‐established quantity for specifying the aromaticity or antiaromaticity of cyclic conjugated molecules is the so‐called aromatic stabilization energy (ASE), which can be derived—either experimentally or theoretically—from appropriate homodesmotic reactions. To gain further insight into the origin of aromaticity, several schemes have been devised to partition ASE into nuclear and electronic as well as σ and π contributions, some of which have resulted in contradictory statements about the driving force of aromatic stabilization. Currently, these contradictions have not been resolved and have resulted in a confusing distinction between two different types of aromaticity: extrinsic and intrinsic aromaticity. By investigating different homodesmotic reactions we show that, in contrast to ASE itself, the individual contributions that enter the ASE can strongly depend on the type of reaction. Caution is therefore advised if conclusions or physical interpretations are derived from the individual components. The contradictions result from the fact that some reactions suffer from an imbalance in the number of interaction terms at the two sides of the reaction equation. The concept of isointeractional reactions is introduced and results in the elimination of the imbalance. For these reactions, the contradictions disappear and the distinction between intrinsic and extrinsic aromaticity becomes unnecessary. As far as the σ–π partitioning is concerned, several schemes proposed in the literature are compared. Contradictory results are obtained depending on the partitioning scheme and reaction used. In this context, it is demonstrated that for the partitioning of the electron–electron interaction, the scheme introduced by Jug and Köster is the one that is most theoretically grounded.
Zebrafish bashful/laminin‐α1 mutants exhibit multiple axon guidance defects
Authors: Paulus Jeremiah D. , Halloran Mary C.
Published: October 2005

Laminin is known to provide a highly permissive substratum and in some cases directional information for axon outgrowth in vitro. However, there is still little known about laminin function in guiding axons in vivo. We investigated the axon guidance role of laminin‐α1 in the developing zebrafish nervous system. Analysis of zebrafish bashful (bal)/laminin‐a1 mutants revealed multiple functions for laminin‐α1 in the outgrowth and guidance of central nervous system (CNS) axons. Most CNS axon pathways are defective in bal embryos. Some axon types, including retinal ganglion cell axons, early forebrain axons, and hindbrain reticulospinal axons, make specific pathfinding errors, suggesting laminin‐α1 is required for directional decisions. Other axon tracts are defasciculated or not fully extended in bal embryos, suggesting a function for laminin‐α1 in regulating adhesion or providing a permissive substratum for growth. In addition, some neurons have excessively branched axons in bal, indicating a potential role for laminin‐α1 in branching. In contrast to CNS axons, most peripheral axons appear normal in bal mutants. Our results, thus, reveal important and diverse functions for laminin‐α1 in guiding developing axons in vivo. Developmental Dynamics 235:213–224, 2006. © 2005 Wiley‐Liss, Inc.
Sema3D, Sema3F, and Sema5A are expressed in overlapping and distinct patterns in chick embryonic heart
Authors: Jin Zhe , Chau Mary D. , Bao Zheng‐Zheng
Published: October 2005

An increasing number of axon guidance cues have been shown recently to play important roles in the development of non‐neural tissues. Semaphorins comprise one of the largest conserved families of axon guidance factors. We analyzed the expression patterns of Sema3D, Sema3F, and Sema5A genes in the chick embryonic heart by in situ hybridization. All three genes are expressed in the cardiac cushion regions, both in the mesenchymal cells, and epithelial cells in the endocardial layer, during the period of cardiac remodeling. In addition to the overlapping expression patterns in the cardiac cushion regions, these genes also exhibit distinct expression patterns in the developing heart: Sema3D is additionally expressed in the tips of the ventricular trabeculae; Sema3F is expressed in a subset of cells scattered throughout the ventricles; and Sema5A is expressed in the newly formed atrioventricular valves. The overlapping and distinct expression patterns of these genes suggest that they may play important roles in heart development. Developmental Dynamics 235:163–169, 2006. © 2005 Wiley‐Liss, Inc.
Hypoxia suppresses the production of matrix metalloproteinases and the migration of humanmonocyte‐derived dendritic cells
Authors: Zhao Wenli , Darmanin Stephanie , Fu Qiang , Chen Jian , Cui Hongyan , Wang Jingxin , Okada Futoshi , Hamada Jun‐ichi , Hattori Yuu‐ichi , Kondo Takeshi , Hamuro Junji , Asaka Masahiro , Kobayashi Masanobu
Published: October 2005

As most solid tumors are hypoxic, dendritic cells (DC) in solid tumors are also exposed to hypoxia. While many adaptation responses of tumor cells to hypoxia are known, it is yet to be determined how hypoxia affects the functions of DC. To explore the effects of hypoxia on the functions of DC, we compared the expression of surface markers, cytokines, chemokine receptors and matrix metalloproteinases (MMP) of human monocyte‐derived DC (hmDC) differentiated under hypoxia to those differentiated under normoxia. Both groups of hmDC expressed similar levels of surface markers and cytokines. However, expression of MMP‐9 and membrane type‐1‐MMP, as well as migrating activity, was significantly suppressed in hmDC differentiated under hypoxia compared with their normoxia counterparts. We also demonstrated that trichostatin A restored the production of MMP‐9 in hmDC, under hypoxia. Collectively, our findings show that a hypoxic microenvironment suppresses the production of MMP in hmDC, most probably through the deacetylation of promoter regions of MMP, thus suppressing the migrating activity of hmDC. Our results suggest that the hypoxic microenvironment in solid tumor tissues may suppress the function of DC.
The CD3 γϵ/δϵ signaling module provides normal T cell functions in the absence of the TCR ζ immunoreceptor tyrosine‐based activation motifs
Authors: Pitcher Lisa A. , Mathis Meredith A. , Young Jennifer A. , DeFord Laura M. , Purtic Bozidar , Wulfing Christoph , van Oers Nicolai S. C.
Published: October 2005

T cell receptor (TCR) signal transduction is mediated by the immunoreceptor tyrosine‐based activation motifs (ITAM). The ten ITAM in the TCR complex are distributed in two distinct signaling modules termed TCR ζζ and CD3 γϵ/δϵ. To delineate the specific role of the ζ ITAM in T cell development and TCR signal transmission, we compared the properties of T cells from different TCR ζ‐transgenic lines wherein tyrosine‐to‐phenylalanine substitutions had been introduced in the ζ subunit. These lines lack selected phosphorylated forms of TCR ζ including just p23, both p21 and p23, or all phospho‐ζ derivatives. We report herein that the efficiency of positive selection in HY TCR‐transgenic female mice was directly related to the number of ζ ITAM in the TCR. In contrast, TCR‐mediated signal transmission and T cell proliferative responses following agonist peptide stimulation were similar and independent of the ζ ITAM. Only the duration of MAPK activation was affected by multiple ζ ITAM substitutions. These results strongly suggest that the ITAM in the CD3 γϵ/δϵ module can provide normal TCR signal transmission, with ζ ITAM providing a secondary function facilitating MAPK activation and positive selection.
ABCB1 transporter discriminates human resting naive B cells from cycling transitional and memory B cells
Authors: Wirths Stefan , Lanzavecchia Antonio
Published: October 2005

The exact identification of B cell subsets is instrumental to understand their dynamics under physiological and pathological conditions. Human memory B cells are currently identified according to the expression of CD27, which is absent on naive B cells. We report here that the ATP‐binding cassette (ABC)B1 transporter is exclusively present on mature CD27– naive B cells, while it is absent in CD27+ memory B cells and in a heterogeneous subset of CD27– cells that comprise both switch memory and transitional B cells. Thus, ABCB1 activity precisely discriminates naive from transitional and all memory B cells. Using this improved method to discriminate human B cell subsets, and Ki67 staining to identify recently divided cells, we show that in both cord blood and adult peripheral blood, mature naive B cells are quiescent while transitional B cells and memory B cells have a high in vivo turnover.
An essential role for Rxrα in the development of Th2 responses
Authors: Du Xin , Tabeta Koichi , Mann Navjiwan , Crozat Karine , Mudd Suzanne , Beutler Bruce
Published: October 2005

A viable hypomorphic allele of mouse retinoid X receptor α (Rxrα) was created by random germline mutagenesis. The mutation (I273N) alters the ligand binding and heterodimerization domain, and causes a 90% decline in ligand‐inducible transactivation. Homozygotes develop progressive alopecia and dermal cysts, and progressive exaggeration of Th1 and loss of Th2 responses to antigen. Th1 skewing is directly caused by aberrant function of both antigen‐presenting cells and naïve CD4 T cells; the predominant Th1 response to antigen is attributable to decreased suppression of regulatory T cells in mutant mouse. Dietary depletion of vitamin A in Th2‐prone wild‐type mice mimics the immune phenotype caused by the mutation. Hence, RXRα plays an important post‐developmental role in the regulation of adaptive immune responses, and provides a plausible link between nutritional environment and the type of adaptive response that results from immunization.

See accompanying commentary http://dx.doi.org/10.1002/eji.200535588
Enantioselective Epoxidation of α,β‐Enones by Electrophilic Activation with a BINOL–Zinc Catalyst
Authors: Minatti Ana , Dötz Karl Heinz
Published: October 2005

The combination of BINOL and a dialkylzinc reagent R2Zn affords, in situ, a catalyst for homogeneous epoxidation of (E)‐α,β‐enones to the corresponding trans‐epoxy ketones. tert‐Butyl hydroperoxide (TBHP) and cumene hydroperoxide (CMHP) are effective terminal oxidants for this process. Enantiomeric excesses of up to 96 % can be achieved conveniently at room temperature. Mechanistic investigations point towards an electrophilic activation of the substrates by the chiral BINOL–zinc catalyst and a subsequent nucleophilic attack of the oxidant. This mechanistic proposal is supported additionally by a non‐linear effect, the absolute product configuration as well as NMR studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Impedance Spectroscopy: A Powerful Tool for Rapid Biomolecular Screening and Cell Culture Monitoring
Authors: K'Owino Isaac O. , Sadik Omowunmi A.
Published: October 2005

Dielectric spectroscopy or Electrochemical impedance spectroscopy (EIS) is traditionally used in corrosion monitoring, coatings evaluation, batteries, and electrodeposition and semiconductor characterization. However, in recent years, it is gaining widespread application in biotechnology, tissue engineering, and characterization of biological cells, disease diagnosis and cell culture monitoring. This article discusses the principles and implementation of dielectric spectroscopy in these bioanalytical applications. It provides examples of EIS as label‐free, mediator‐free strategies for rapid screening of biocompatible surfaces, monitoring pathogenic bacteria, as well as the analysis of heterogeneous systems, especially biological cells and tissues. Descriptions are given of the application of nanoparticles to improve the analytical sensitivities in EIS. Specific examples are given of the detection of base pair mismatches in the DNA sequence of Hepatitis B disease, TaySach's disease and Microcystis spp. Others include the EIS detection of viable pathogenic bacteria and the influence of nanomaterials in enhancing biosensor performance. Expanding applications in tissue engineering such as adsorption of proteins onto thiolated hexa(ethylene glycol)‐terminated (EG6) self‐assembled monolayer (SAM) are discussed.
Conducting Polymer‐Based Solid‐State Ion‐Selective Electrodes
Authors: Bobacka Johan
Published: October 2005

Conducting polymers, i.e., electroactive conjugated polymers, are useful both as ion‐to‐electron transducers and as sensing membranes in solid‐state ion‐selective electrodes. Recent achievements over the last few years have resulted in significant improvements of the analytical performance of solid‐contact ion‐selective electrodes (solid‐contact ISEs) based on conducting polymers as ion‐to‐electron transducer combined with polymeric ion‐selective membranes. A significant amount of research has also been devoted to solid‐state ISEs based on conducting polymers as the sensing membrane. This review gives a brief summary of the progress in the area in recent years.
Sex and symmetry differences in hippocampal volumetrics: Before and beyond the opening of the crus of the fornix
Authors: Maller Jerome J. , Réglade‐Meslin Chantal , Anstey Kaarin J. , Sachdev Perminder
Published: October 2005

Published normative volumetrics of the hippocampus (HC) vary substantially. While the protocol suggested by Watson et al. (Neurology 42 (1992) 1743–1750; Arch Neurology 54 (1997) 1521–1531) is the most frequently adhered to, this leaves the posterior section of the HC tail unmeasured, which has been estimated to be in the order of 2–4 mm, representing 5–10% of total HC volume. The objective of the current study was to compare HC volumes according to the method of Watson et al. (Neurology 42 (1992) 1743–1750; Arch Neurology 54 (1997) 1521–1531) against those measured to include the posterior tail section. From a random community sample of 60–64 yr old individuals, 478 subjects underwent magnetic resonance imaging brain scans. Of these, 452 scans (238 males and 214 females) were adequate for hippocampal measurement. The scans comprised whole brain T1‐ weighted and T2‐weighted FLAIR images. One hundred and fifty scans were randomly selected for the measurement of HC volumes beyond the opening of the crus of the fornix by manual tracings on T1‐weighted images by a trained operator. Intracranial volume (ICV) and total brain volume (TBV) were measured using an automated program. We found that the posterior HC tail extended for a mean of just over 5 mm and comprised 11% of total HC volume. Males had significantly larger raw HC volumes, and while normalization with ICV or TBV reversed this pattern, it was significant only when the posterior HC tail was included in the measurement. In conclusion, this study showed that including the posterior part of the tail can influence the results of HC measurement. An argument is presented that accurate HC volumes should include the entire HC and not exclude the tail. © 2005 Wiley‐Liss, Inc.
Lesion‐induced gelsolin upregulation in the hippocampus following entorhinal deafferentation
Authors: Dong Jing‐Hui , Ying Guo‐Xin , Liu Xin , Wang Wen‐Yuan , Wang Yan , Ni Zi‐Mei , Zhou Chang‐Fu
Published: October 2005

Gelsolin is an actin‐binding protein that regulates actin filament‐severing and capping activity in the various processes of cell motilities. Here, we report the expression of gelsolin mRNA and protein in the hippocampus following transections of the entorhinal afferents. Northern blot analysis showed that transcript of gelsolin was upregulated in a transient manner in the deafferented hippocampus by 1.3‐, 2.1‐, 1.7‐, and 1.1‐ folds of controls, respectively, at 1, 3, 7, and 15 days postlesion (dpl). In situ hybridization and immunohistochemistry confirmed the temporal expression of gelsolin specifically in the entorhinally denervated zones: the stratum lacunosum‐molecular (SLM) of the hippocampus and the outer molecular layer (OML) of the dentate gyrus (DG), which initiated as early as at 1 dpl, reached the maximum at 3 dpl, remained prominently elevated by 7 dpl, and discernibly higher at 15 dpl than that of controls. Double labeling of either gelsolin mRNA or protein with markers of glial cells (Griffonia simplicifolia IB4 and CD11b for microglial cells, GFAP for astroglial cells) revealed that gelsolin was highly expressed by both activated microglia and astrocytes. The results suggest that the spatiotemporal upregulation of gelsolin in the hippocampus is induced by entorhinal deafferentation, and that gelsolin would participate in the activation processes of both microglial and astroglial cells and thereby, indirectly play important roles in the subsequent lesion‐induced neural reorganization in the hippocampus following entorhinal deafferentation. © 2005 Wiley‐Liss, Inc.
Dissociable effects of hippocampus lesions on expression of fear and trace fear conditioning memories in rats
Authors: Burman Michael A. , Starr Mark J. , Gewirtz Jonathan C.
Published: October 2005

The role of the hippocampus in memory is commonly investigated by comparing fear conditioning paradigms that differ in their reliance on the hippocampus. For example, the dorsal (septal) portion of the hippocampus is involved in trace, but not delay fear conditioning, two Pavlovian paradigms in which only the relative timing of stimulus presentation is varied. However, a growing literature implicates the ventral (temporal) portion of the hippocampus in the expression of fear, irrespective of prior training. The current experiments evaluated the relative contributions of the dorsal and ventral portions of the hippocampus to trace fear conditioning specifically vs. the expression of conditioned fear in general. Lesions restricted to the dorsal hippocampus blocked acquisition of trace fear conditioning. Larger lesions, also including an adjacent portion of the ventral hippocampus, were required to impair retrieval of trace fear conditioning. Delay fear conditioning was not disrupted in either case. In contrast, lesions that encompassed almost the entire dorsal and ventral hippocampus disrupted expression of both trace and delay fear conditioning. The current data suggest distinct roles in fear conditioning for three regions of the hippocampus: the septal zone is required for acquisition of trace fear conditioning, a larger portion of the hippocampus is critical for memory retrieval, and a region including the temporal zone is required for expression of both trace and delay fear conditioning. These findings are consistent with evidence suggesting the neuroanatomical and functional segregation of the hippocampus into three zones along its septal–temporal axis. © 2005 Wiley‐Liss, Inc.
Enriched environment exposure regulates excitability, synaptic transmission, and LTP in the dentate gyrus of freely moving rats
Authors: Irvine Gemma I. , Logan Barbara , Eckert Michael , Abraham Wickliffe C.
Published: October 2005

Performance in hippocampus‐dependent and other tasks can be improved by exposure to an enriched environment (EE), but the physiological changes in neural function that may mediate these effects are poorly understood. To date, there have been conflicting reports regarding potential mechanisms, such as an increase in basal synaptic transmission, an increase in cell excitability, or altered synaptic plasticity. Here, we reexamined in freely moving animals the conditions under which varying degrees of EE exposure might lead to increases in synaptic or neural function in the dentate gyrus of the hippocampus. Adult male Sprague‐Dawley rats were chronically implanted with stimulating and recording electrodes in the perforant path and dentate gyrus, respectively, and housed singly in standard cages. After stable recordings were established for field excitatory postsynaptic potentials (fEPSPs) and population spikes (PSs), the effects of various degrees of periodic novel environment exposure for 19 days were assessed. Exposure to an EE increased fEPSPs, but only when animals were kept in nominally low‐stress housing conditions. An increase in granule‐cell excitability, as evidenced by PS increases, was induced by all environmental treatments with the greatest effect being induced by overnight EE exposure. EE exposure did not change the level of long‐term potentiation (LTP) induced by a moderate high‐frequency tetanus, but continued EE exposure post‐tetanus produced a significantly faster decay of LTP relative to control animals. These results suggest that, in adult animals, EE exposure may augment hippocampal information processing, but may also speed turnover of information in the hippocampus during the maintenance period. © 2005 Wiley‐Liss, Inc.
Steady‐ and unsteady‐state lumped parameter modelling of tritium and chlorofluorocarbons transport: hypothetical analyses and application to an alpine karst aquifer
Authors: Ozyurt N. Nur , Bayari C. Serdar
Published: October 2005

Determination of a groundwater's mean residence time with the aid of environmental tracers is common in hydrogeology. Many of the lumped parameter (LP) applications used for this purpose have been based on steady‐state models. However, the results may be misleading if a steady LP model is used to simulate the environmental tracer transport in an unsteady aquifer. To test this hypothesis, the results of steady and unsteady versions of several LP models were evaluated theoretically and in an alpine karst aquifer case by using tritium, oxygen‐18 and chlorofluorocarbons (CFCs). The results reveal that the mean residence times obtained may be significantly different between the steady and unsteady versions of the same model. For the karst aquifer investigated, a serially connected exponential and a plug flow model were run under unsteady conditions. It is shown that outflux calibration with an unsteady model provides a firm basis in evaluating the results of models. An outflux‐calibrated unsteady model predicted reasonably the observed series of water isotopes. The calibrated model's CFCs output overpredicts the observed concentrations, probably because of the time lag in the unsaturated zone of the alpine karst aquifer. Copyright © 2005 John Wiley & Sons, Ltd.
Origin of shallow groundwater of Csepel Island (south of Budapest, Hungary, River Danube): isotopic and chemical approach
Authors: Fórizs I. , Berecz T. , Molnár Z. , Süveges M.
Published: October 2005

The shallowest aquifer of the alluvial Csepel Island is used for drinking water supply for Budapest and the surrounding villages. A previous two‐dimensional hydraulic model failed to explain many observations; therefore, a three‐dimensional hydraulic model was constructed using the software application MODFLOW. Isotopic and hydrogeochemical investigations were carried out during the period 1998 to 2002 in order to provide model data. Four water sources have been identified, having different isotopic (and chemical) characteristics. Danube water is characterized by seasonally varying δ18O values: its unweighted mean δ18O value is −10·9‰ for the years 1998 to 2002. The most negative δ18O values occur in late spring and summertime. Average tritium content is 20 TU. Infiltrated precipitation has δ18O values between −9·0 and −9·5‰. The average tritium content of the precipitation is 10 TU, and that of infiltrated precipitation must be close to this value and about half that of the Danube. The δ18O value of lake water is > −9·0‰. Its stable isotope composition plots on the right side of the local meteoric water line on the δD–δ18O diagram. Ascending deep groundwater (sampled depth of 20–140 m) has δ18O values between −12·0 and −13·5‰. Its radiocarbon age is between 16 000 and 30 000 years BP, probably infiltrated during and around the last glacial maximum (Würm III) period of the latest glaciation. Copyright © 2005 John Wiley & Sons, Ltd.
Oxygen and hydrogen isotopic composition of major Indian rivers: a first global assessment
Authors: Lambs L. , Balakrishna K. , Brunet F. , Probst J. L.
Published: October 2005

Nine major rivers have been sampled around the Indian subcontinent to give an overview of the surface water characteristics. Both18O and deuterium have been measured to determine the origin of the water and the possible evapotranspiration process. The major ions have also been analysed to obtain complementary information. Although some basins have been studied previously (mainly in the north), this is the first attempt at a wider investigation of major Indian rivers. The results are discussed from the perspective of the hydroclimatological, geographical and geological specificity of the river basins. δ18O values vary from light‐isotope‐enriched Himalayan rivers to heavy‐isotope‐enriched peninsular Indian rivers in a northwest–southeast gradient across the subcontinent. There is more evapotranspiration, leading to heavy isotope enrichment, in the peninsular (southern Deccan) rivers compared with the light‐isotope‐enriched snow‐ and glacier‐melt‐derived waters of the Himalayan rivers. The δ18O values of Indian rivers correspond roughly to the δ18O values of the rains falling over the subcontinent. However, the influence of tributaries is dominant over rainfall in rivers like the Narmada and Tapti. The Cauvery and Krishna rivers show maximum evapotranspiration and sodium pollution, as indicated by the δ18O values, deuterium excess and major ion data. Copyright © 2005 John Wiley & Sons, Ltd.
Interannual variation of stable isotopes in precipitation at Bangkok in response to El Ñino Southern Oscillation
Authors: Ichiyanagi Kimpei , Yamanaka Manabu D.
Published: October 2005

Evidence for a close relationship between the interannual variation of stable isotopes in precipitation and the El Ñino Southern Oscillation (ENSO) is presented for Bangkok, Thailand. Anomalies of sea surface temperature in the Niño‐3 region of the equatorial Pacific (ENSO index) and δ18O in precipitation in Bangkok were positively correlated for May and October. The composite mean precipitation was much greater in the isotopic low phase than in the high phase for both May and October. This suggests that the amount of precipitation is the main factor determining the observed variation of stable isotopes in precipitation in Bangkok. Composite analyses of 850 hPa temperature, evaporation, outgoing longwave radiation (OLR), and precipitation showed that the variation in the amount of precipitation in Bangkok is a response to the ENSO–Asian summer monsoon coupling in May, and a direct response to ENSO in October. The composite mean d‐excess values in both the low and high phases in October and in the low phase in May were about 10‰, and were less than 7‰ during the high phase in May. A large difference in the evaporation field between the low and high phases of May exists over the Indian Ocean, suggesting that evaporation was not in equilibrium during the high phase in May. Future studies will consider the precipitation amount effect based on daily or event‐based sampling. Copyright © 2005 John Wiley & Sons, Ltd.
Simulation of δ18O in precipitation by the regional circulation model REMOiso
Authors: Sturm Kristof , Hoffmann Georg , Langmann Bärbel , Stichler Willibald
Published: October 2005

The first results of a regional circulation model REMOiso fitted with water isotope diagnostics are compared with various isotope series from central Europe. A 2 year case study is conducted from March 1997 to February 1999 centred over Europe, analysing daily and monthly measurements. Isotope signals over Europe are dominated by the typical isotopic effects such as temperature, continental and altitude effects, both on annual and seasonal scales. These well‐known isotopic effects are successfully reproduced by REMOiso, using two different boundary data sets. In a first simulation, the European Centre for Medium‐range Weather Forecasts (ECMWF) analyses serve as boundary conditions, where water isotopes were parameterized by a simple temperature dependence. In a second simulation, boundary conditions both for climatic and isotopic variables are taken from the ECHAMiso general circulation model output. The comparison of both simulations shows a very high sensitivity of the simulated δ18O signal to boundary conditions. The ECMWF‐nested simulation shows an average offset of −4·5‰ in mean δ18O values and exaggerated seasonal amplitude. The ECHAM‐nested simulation represents correctly the observed mean δ18O values, although with a dampened seasonality. REMOiso's isotope module is further validated against daily δ18O measurements at selected stations (Nordeney, Arkona and Hohenpeissenberg) situated in Germany. Copyright © 2005 John Wiley & Sons, Ltd.
A multireference configuration interaction method based on the separated electron pair wave functions
Authors: Ma Jing , Li Shuhua , Li Wei
Published: October 2005

A multireference configurational interaction method based on the separated electron pair (SEP) wave functions, SEP‐CI approach, has been developed as an approximation to the traditional CASSCF method. It differs from the CASSCF method in that active orbitals are obtained from the SEP wave function without further optimization in the subsequent CI calculations, and the active space is automatically constructed according to the occupation coefficients of SEP natural orbitals. These features make the present SEP‐CI method computationally much less demanding than the CASSCF method. The applicability of the SEP‐CI method is illustrated with sample calculations on the insertion reaction of BeH2 and dissociation energies of LiH, BH, FH, H2O, and N2. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 39–47, 2006
Isolation and characterization of lymphatic microvascular endothelial cells from human tonsils
Authors: Garrafa Emirena , Alessandri Giulio , Benetti Anna , Turetta Daniela , Corradi Attilio , Cantoni Anna Maria , Cervi Edoardo , Bonardelli Stefano , Parati Eugenio , Giulini Stefano Maria , Ensoli Barbara , Caruso Arnaldo
Published: October 2005

Human lymphatic endothelial cells (LECs) have isolated prevalently from human derma and tumors. As specialized lymphatic organs within the oropharynx, palatine tonsils are easily obtained and rich in lymphatic venules. Using a two‐step purification method based on the sorting of endothelial cells with Ulex Europaeus Agglutinin 1 (UEA‐1)‐coated beads, followed by purification with monoclonal antibody D2–40, we successfully purified LECs from human palatine tonsils. The LECs were expanded on flasks coated with collagen type 1 and fibronectin for up to 8–10 passages and then analyzed for phenotypic and functional properties. Cultured cells retained the phenotypic pattern of the lymphatic endothelium of palatine tonsils and expressed functional VEGFR‐3 molecules. In fact, stimulation with VEGFR‐3 ligand, the vascular endothelium grow factor C, induced a marked increase in cell proliferation. Similarly to blood endothelial cells (BECs), LECs were able to form tube‐like structure when seeded in Cultrex basement membrane extract. Comparative studies performed on LECs derived from palatine tonsils and iliac lymphatic vessels (ILVs), obtained with the same procedures, showed substantial discrepancies in the expression of various lymphatic markers. This points to the existence of micro‐ and macrovessel‐derived LECs with different phenotypes, possibly involving different biological activities and functions. Palatine tonsil‐ and ILV‐derived LECs may, therefore, represent new models for investigating function and biochemical properties of these lymphatic endothelia. J. Cell. Physiol. 207: 107–113, 2006. © 2005 Wiley‐Liss, Inc.
Elastic fiber formation: A dynamic view of extracellular matrix assembly using timer reporters
Authors: Kozel Beth A. , Rongish Brenda J. , Czirok Andras , Zach Julia , Little Charles D. , Davis Elaine C. , Knutsen Russell H. , Wagenseil Jessica E. , Levy Marilyn A. , Mecham Robert P.
Published: October 2005

To study the dynamics of elastic fiber assembly, mammalian cells were transfected with a cDNA construct encoding bovine tropoelastin in frame with the Timer reporter. Timer is a derivative of the DsRed fluorescent protein that changes from green to red over time and, hence, can be used to distinguish new from old elastin. Using dynamic imaging microscopy, we found that the first step in elastic fiber formation is the appearance of small cell surface‐associated elastin globules that increased in size with time (microassembly). The elastin globules are eventually transferred to pre‐existing elastic fibers in the extracellular matrix where they coalesce into larger structures (macroassembly). Mechanical forces associated with cell movement help shape the forming, extracellular elastic fiber network. Time‐lapse imaging combined with the use of Timer constructs provides unique tools for studying the temporal and spatial aspects of extracellular matrix formation by live cells. J. Cell. Physiol. 207: 87–96, 2006. © 2005 Wiley‐Liss, Inc.
Transverse relaxation effect of MRI contrast agents: A crucial issue for quantitative measurements of cerebral perfusion
Authors: Kiselev Valerij G.
Published: October 2005

Quantitative cerebral perfusion imaging using dynamic susceptibility contrast (DSC) MRI requires the dynamic measurement of changes in contrast agent concentration in cerebral tissue and its feeding artery. In this work the tracer kinetics approach to general tracer‐based perfusion imaging is reviewed. In the typical practical setting, measurements of change in transverse relaxation (ΔR2) derived from MR signals are assumed to be substitutes for true concentration measurements. The implications and limitations of this assumption are reviewed in the light of various results obtained in theoretical, simulated, and experimental studies. The mechanisms of R2 changes in biological media are discussed. These mechanisms operate over different spatial scales and differentially influence gradient‐echo (GE) and spin‐echo (SE) MRI signals. This differential sensitivity can be used to assess vessel size in the microvasculature. Finally, the need for well controlled experimental data to provide input parameters and/or experimental tests of theoretical models is emphasized. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Bolus dispersion issues related to the quantification of perfusion MRI data
Authors: Calamante Fernando
Published: October 2005

Quantification of cerebral blood flow (CBF) using dynamic‐susceptibility contrast (DSC) MRI relies on the deconvolution of the arterial input function (AIF). The AIF is commonly measured in a major artery (e.g., the middle cerebral artery), and the estimated function is used as a global AIF for the whole slice. However, the presence of bolus delay and dispersion between the artery and the tissue of interest can introduce significant errors in CBF quantification. While several methods have been introduced to minimize or eliminate the effects of bolus delay, the correction of bolus dispersion is more difficult to address because it requires a model for the vascular bed. This article summarizes how this dispersion effect can be incorporated into the model for CBF quantification, and discusses the magnitude of the errors introduced. Furthermore, alternative methods for correcting or minimizing the effects of bolus dispersion in the quantification of CBF are reviewed. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Principles of cerebral perfusion imaging by bolus tracking
Authors: Østergaard Leif
Published: October 2005

The principles of cerebral perfusion imaging by the method of dynamic susceptibility contrast magnetic resonance imaging (DSC‐MRI) (bolus tracking) are described. The MRI signals underlying DSC‐MRI are discussed. Tracer kinetics procedures are defined to calculate images of cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT). Two general categories of numerical procedures are reviewed for deriving CBF from the residue function. Procedures that involve deconvolution, such as Fourier deconvolution or singular value decomposition (SVD), are classified as model‐independent methods because they do not require a model of the microvascular hemodynamics. Those methods in principle also yield a measure of the tissue impulse response function and the residue function, from which microvascular hemodynamics can be characterized. The second category of methods is the model‐dependent methods, which use models of tracer transport and retention in the microvasculature. These methods do not yield independent measures of the residue function and may introduce bias when the physiology does not follow the model. Statistical methods are sometimes used, which involve treating the residue function as a deconvolution kernel and optimizing (fitting) the kernel from the experimental data using procedures such as maximum likelihood. Finally, other hemodynamic indices that can be measured from DSC‐MRI data are described. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Quantifying CBF with arterial spin labeling
Authors: Buxton Richard B.
Published: October 2005

The basic principles of measuring cerebral blood flow (CBF) using arterial spin labeling (ASL) are reviewed. The measurement is modeled by treating the ASL method as a magnetic resonance imaging (MRI) version of a microsphere study, rather than a diffusible tracer study. This approach, particularly when applied to pulsed ASL (PASL) experiments, clarifies that absolute calibration of CBF primarily depends on global properties of blood, rather than local tissue properties such as the water partition coefficient or relaxation time. However, transit delays from the tagging region to the image voxel are a potential problem in all standard ASL methods. The key to quantitative CBF measurements that compensate for this systematic error is to create a well‐defined bolus of tagged blood and to ensure that all of the bolus has been delivered to an imaging voxel at the time of measurement. Two practical technical factors considered here are 1) producing a tagged bolus with a well‐defined temporal width and 2) accounting for reduction in magnitude of the tagged magnetization due to relaxation. The ASL approach has the potential to provide a robust estimation of CBF, although the timing of water exchange into tissue and the effects of pulsatile flow require further investigation. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Facile Surface Superhydrophilic Modification: NVP/MBA Inverse Microemulsion Surface‐Grafting Polymerization Initiated by UV Light
Authors: Wang Yongxin , Deng Jianping , Zhong Wenbin , Kong Lingbing , Yang Wantai
Published: October 2005

Summary: Superhydrophilic modification of poly(propylene) and poly(ethylene terephthalate) films' surfaces was realized by the UV‐initiated surface photografting of a N‐vinyl pyrrolidone/N,N′‐methylenebisacrylamide inverse microemulsion. AFM characterization of the treated films' surface revealed that it was the grafted quasi‐bimodal (ca. 45 and 110 nm) particles of cross‐linked poly(N‐vinyl pyrrolidone) that led to superhydrophilicity of the surface. The grafted nanometer‐scale particles showed little influence on the transparency of the substrate's surface, but endowed long‐term stability to the superhydrophilicity.

The surface morphology of the PP film grafted with a NVP/MBA inverse microemulsion via a one‐step method. Quasi‐bimodal particles (ca. 45 nm and 110 nm) were tethered on the film's surface, and the corresponding surface water CA fell below 5°.

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The surface morphology of the PP film grafted with a NVP/MBA inverse microemulsion via a one‐step method. Quasi‐bimodal particles (ca. 45 nm and 110 nm) were tethered on the film's surface, and the corresponding surface water CA fell below 5°.
Vapor‐Based Synthesis of Poly[(4‐formyl‐p‐xylylene)‐co‐(p‐xylylene)] and Its Use for Biomimetic Surface Modifications
Authors: Nandivada Himabindu , Chen Hsien‐Yeh , Lahann Joerg
Published: October 2005

Summary: The vapor‐based synthesis and characterization of a reactive polymer, poly[(4‐formyl‐p‐xylylene)‐co‐(p‐xylylene)] (1), have been reported. The reactive polymer coating enables the immobilization of oligosaccharides via the chemoselective aldehyde‐hydrazide coupling reaction.

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Self‐Organizing Alignment of Carbon Nanotubes in Thermoplastic Polyurethane
Authors: Chen Wei , Tao Xiaoming
Published: October 2005

Summary: A simple compounding technique for the fabrication of polymer nanocomposites with single‐walled carbon nanotubes having exceptional alignment and improved mechanical properties is described. The aligned‐nanotube composite was prepared by dissolving single‐walled carbon nanotubes in a solution of thermoplastic polyurethane and tetrahydrofuran. Solvent‐polymer interactions that induce the orientation of soft chain segments during the swelling and moisture curing stage are believed to serve as a driving force for the macroscopic alignment of the carbon nanotubes.

Alignment of single‐walled carbon nanotubes in thermoplastic polyurethane during polar solvent exposure.

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Alignment of single‐walled carbon nanotubes in thermoplastic polyurethane during polar solvent exposure.
Sensitivity and specificity of a self‐administered questionnaire for familial screening of adult‐onset dystonia
Authors: Aniello Maria Stella , Martino Davide , Masi Gianluca , Livrea Paolo , Defazio Giovanni
Published: October 2005

We developed a self‐administered questionnaire for screening the most common adult‐onset dystonias. It was tested in 90 first‐degree relatives of 22 adult‐onset dystonia patients, yielding 79% sensitivity and 94% specificity. Simulation of a case‐finding procedure based on serial application of the questionnaire and clinical examination of both subjects screening positive and subjects screening negative who had < 8 years of schooling increased sensitivity to 95% and specificity to 100%. This questionnaire may be an important screening resource for familial aggregation studies to be used in the context of a complex case‐finding procedure. © 2005 Movement Disorder Society
Dicondensed indolinobenzospiropyrans as precursors of thermo‐ and photochromic spiropyrans. Part II: assignment of 1H and 13C NMR spectra
Authors: Keum Sam‐Rok , Ahn Su‐Mi , Roh Se‐Jung , Park Su‐Jin , Kim Sung‐Hoon , Koh Kwangnak
Published: October 2005

The 1H and 13C NMR spectra of dicondensed indolinobenzospiropyrans as precursors of thermo‐ and photochromic spiropyrans, DC1–DC5, were completely assigned. Especially, the 1H assignment and coupling characteristics of the diastereotopic protons at the carbon‐3 position of the benzopyran rings were achieved by conducting 1H–1H COSY and nOe experiments. The dihedral angles (θ1, θ2 and θ3) calculated from the experimental values of the vicinal coupling constants (3J) of DC5 are in good agreement with the observed values in the solid state. All of the carbons in the DC dye molecules were investigated through a combination of heteronuclear 2D‐shift correlation spectroscopy (HETCOR) and DEPT135. Copyright © 2005 John Wiley & Sons, Ltd.
Carbon‐13 and proton NMR assignments of a new agathisflavone derivative
Authors: de Carvalho Mario Geraldo , do Rocha Gomes Mario Sergio , Fernandes Pereira André Hilário , de Souza Daniel Juliana Feijó , Schripsema Jan
Published: October 2005

The 1H and 13C NMR spectra of 5‐acetyl‐7,4′‐dimethoxyflavone‐(6–8″)‐5″‐acetyl‐7″,4‴‐dimethoxyflavone, a new agathisflavone derivative, were completely assigned on the basis of 1D and 2D NMR techniques. Copyright © 2005 John Wiley & Sons, Ltd.
Noninvasive monitoring of gene correction in dystrophic muscle
Authors: Walter Glenn , Cordier Laurence , Bloy Dorothy , Lee Sweeney H.
Published: October 2005

Gene and stem cell transfer have shown tremendous potential in rescuing dystrophic muscle in animal models. However, monitoring of gene transfer efficacy in clinical settings currently requires invasive muscle biopsies. We determined whether 1H‐magnetic resonance spectroscopy (MRS) and imaging (MRI) could be used to noninvasively monitor gene correction in dystrophic skeletal muscle. MRI/MRS measurements were performed in murine models of Limb Girdle (γsg−/−) and Duchenne muscular dystrophy (mdx). Viral delivery of γsg into γsg−/− muscles was achieved using both an adenovirus and an adenoassociated virus. T2‐weighted MRIs consistently revealed hyperintense regions in muscles of dystrophic mice, which agreed well with histologically determined damaged muscle fibers. 1H‐MRS revealed that the increase in T2 in dystrophic muscle is not due to fatty tissue infiltration. Reintroduction of the γsg gene in γsg−/− muscles restored normal muscle histology, membrane stability, and T2 contrast. Expression of γsg also significantly decreased the number of pixels with increased T2 values and MRI contrast agent uptake. Our data demonstrate that therapeutic correction of dystrophic lesions can be noninvasively monitored using endogenous MR contrast. This may be particularly relevant for future interventions in children with muscular dystrophy. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.