bluuebunny/crossref_metadata_2025 huggingface dataset:
Foam fractionation of exo‐lipases from a growing fungus (Pleurotus sapidus)
Authors: Linke Diana , Zorn Holger , Gerken Birte , Parlar Harun , Berger Ralf G.
Published: March 2007

Active lipases were isolated from the culture supernatant of the basidiomycetous fungus Pleurotus sapidus by foam fractionation. The pH value, the gas flow, and the foaming period were systematically varied to optimize the transport of the enzymes into the foam phase. On a 70‐mL scale, a maximum recovery of hydrolytic activity of 95% was obtained at pH 7.0 and 60 mL N2 min−1 after 50 min. The procedure, with minor modifications, was also applicable to native pellet cultures of P. sapidus. The same recovery of 95% was achieved, with purification and enrichment factors of 11.6 and 28.0, respectively.
Influence of cytochrome c on apoptosis induced by Anagrapha (Syngrapha) falcifera multiple nuclear polyhedrosis virus (AfMNPV) in insect Spodoptera litura cells
Authors: Liu Lijun , Peng Jianxin , Liu Kaiyu , Yang Hong , Li Yi , Hong Huazhu
Published: March 2007

We investigated the influence of cytochrome c on apoptosis induced by Anagrapha (Syngrapha) falcifera multiple nuclear polyhedrosis virus (AfMNPV). Microscopic observation revealed that infection of SL‐1 cells with AfMNPV resulted in apoptosis, displaying apoptotic bodies in fluorescent‐stained nuclei of AfMNPV‐infected SL‐1cells. Western blot analysis demonstrated that AfMNPV‐induced apoptosis in insect SL‐1 cells was significantly inhibited by cyclosporin A which blocked a translocation of cytochrome c from the mitochondria to the cytosol. As determined by using AC‐DEVD‐AFC as substrate, the activity of caspase‐3 in AfMNPV‐induced cells was detected as early as 4 h post infection, gradually increased with time extension, and reached a highest level after 16 h of infection. However, activity of caspase‐3 in apoptotic cells decreased in the presence of cyclosporin A (30 μM), indicating that activation of caspase‐3 in SfaMNPV‐induced cells was dependent on the release of cytochrome c from the mitochondria. In addition, cyclosporin A could markedly inhibit mitochondrial transmembrane potential (ΔΨm) disruption in undergoing apoptotic cells. These data indicate that cytochrome c plays a key role in AfMNPV‐induced apoptosis in S. litura cells and may be required for caspase activation during the induction of apoptosis.
Conventional and molecular cytogenetic diagnostic methods in stem cell research: A concise review
Authors: Catalina Purificación , Cobo Fernando , Cortés José L. , Nieto Ana I. , Cabrera Carmen , Montes Rosa , Concha Ángel , Menendez Pablo
Published: March 2007

Regenerative medicine and cell therapy are emerging clinical disciplines in the field of stem cell biology. The most important sources for cell transplantation are human embryonic and adult stem cells. The future use of these human stem cell lines in humans requires a guarantee of exhaustive control with respect to quality control, safety and traceability. Genetic instability and chromosomal abnormalities represent a potential weakness in basic studies and future therapeutic applications based on these stem cell lines, and may explain, at least in part, their usual tumourigenic properties. So, the introduction of the cytogenetic programme in the determination of the chromosomal stability is a key point in the establishment of the stem cell lines. The aim of this review is to provide readers with an up‐to‐date overview of all the cytogenetic techniques, both conventional methods and molecular fluorescence methods, to be used in a stem cell bank or other stem cell research centres. Thus, it is crucial to optimize and validate their use in the determination of the chromosomal stability of these stem cell lines, and assess the advantages and limitations of these cutting‐edge cytogenetic technologies.
The effect of substrate and adsorbed proteins on adhesion, growth and shape of CaCo‐2 cells
Authors: Zemljič Jokhadar Š. , Žnidarčič T. , Svetina S. , Batista U.
Published: March 2007

Extracellular matrix (ECM) proteins play a critical role in many cellular functions, from spreading, migration and proliferation to apoptosis. This role can be altered when proteins of the native ECM are adsorbed to different substrates which cause structural modifications that can influence their biological function. The effects on CaCo‐2 cells of laminin‐1, fibronectin, collagen‐1 and ECM gel adsorbed to glass and to tissue culture polystyrene (PS) were compared in terms of adhesion, proliferation, shapes and spreading of cells in culture. Significant differences between glass and PS surfaces were observed for proliferation and cell shape. Protein surfaces prepared on PS substrates had, in most cases, more pronounced effects on cells than uncoated PS, especially if coated by collagen‐1. Adsorbed ECM gel was the most adhesive for cells, but its effect on cell proliferation was not notably different from the controls (glass or PS). These findings indicate that the choice of the substrate can have a significant effect on experimental results and should be taken into consideration when comparing results obtained on different surfaces.
Evolution of the gene families forming the Pax/Six regulatory network: Isolation of genes from primitive animals and molecular phylogenetic analyses
Authors: Hoshiyama Daisuke , Iwabe Naoyuki , Miyata Takashi
Published: March 2007

Some members of the Pax (paired box) and Six (sine oculis homeobox) gene families function as components of a gene regulatory network controlling eye development. To investigate the early evolution of the genetic interaction between Pax and Six genes, we identified and sequenced members of the Pax and Six gene families from primitive animals. Molecular phylogenetic analyses of the two gene families revealed that all gene duplications that gave rise to different subfamilies occurred before the divergence of cnidarians (ctenophorans) and bilaterians and most of these duplications antedate the sponge‐eumetazoan split. Based on the fact that members of Six‐1/2 subfamily have genetic interactions with several types of Pax genes from three different subfamilies, it is possible that transcriptional regulation between the Pax and Six genes was established in the common ancestor of all metazoans.
Effects of the deficiency of the rhodanese‐like protein RhdA in Azotobacter vinelandii
Authors: Cereda Angelo , Carpen Aristodemo , Picariello Gianluca , Iriti Marcello , Faoro Franco , Ferranti Pasquale , Pagani Silvia
Published: March 2007

In Azotobacter vinelandii the rhdA gene codes for a protein (RhdA) of the rhodanese‐homology superfamily. By combining proteomics, enzymic profiles and ultrastructural observations, the phenotype of an A. vinelandii rhdA mutant was analyzed. We found that the A. vinelandii rhdA mutant, and not the wild‐type strain, accumulated polyhydroxybutyrate. RhdA deficiency enhanced the expression of enzymes of the polyhydroxybutyrate biosynthetic operon, and affected the activity of specific tricarboxylic acid cycle enzymes. The effect was dramatic on aconitase, in spite of comparable expression of aconitase polypeptides in both strains. By using a model system, we found that RhdA triggered protection from oxidants.
DNA‐probes for the highly sensitive identification of single nucleotide polymorphism using single‐molecule spectroscopy
Authors: Friedrich Achim , Hoheisel Jörg D. , Marmé Nicole , Knemeyer Jens-Peter
Published: March 2007

This article presents a new, highly sensitive method for the identification of single nucleotide polymorphisms (SNPs) in homogeneous solutions using fluorescently labeled hairpin‐structured oligonucleotides (smart probes) and fluorescence single‐molecule spectroscopy. While the hairpin probe is closed, fluorescence intensity is quenched due to close contact between the chromophore and several guanosine residues. Upon hybridization to the respective target SNP sequence, contact is lost and the fluorescence intensity increases significantly. High specificity is achieved by blocking sequences containing mismatch with unlabeled oligonucleotides. Time‐resolved single‐molecule fluorescence spectroscopy enables the detection of individual smart probes passing a small detection volume. This method leads to a subnanomolar sensitivity for this single nucleotide specific DNA assay technique.
Diagnosis and Treatment of Cervical Carcinomas
Authors:   ACOG Committee on Practice Bulletins ‐ Gynecology
Published: March 2007

Invasive cervical carcinoma, once the most common reproductive‐tract cancer in the United States, has recently fallen to the rank of third most common. Globally, cervical cancer is a major health problem, with a yearly incidence of 371,000 cases and an annual death of 190,000. The International Federation of Gynecology and Obstetrics (FIGO) recently revisited its staging criteria. In addition, new evidence had documented conclusively that survival rates for women with cervical cancer improve when radiotherapy is combined with cisplatin‐based chemotherapy. This document will describe staging criteria and treatment for cervical carcinoma. For practical purposes, it will focus on the squamous and adenocarcinoma histologies only.
Antimicrobial treatment reduces intestinal microflora and improves protein digestive capacity without changes in villous structure in weanling pigs
Authors: Thymann Thomas , Sørensen Kristina U. , Hedemann Mette S. , Elnif Jan , Jensen Bent B. , Banga-Mboko Henri , Leser Thomas D. , Sangild Per T.
Published: March 2007

The immediate post-weaning period is often associated with gut malfunction and diarrhoea for young pigs. Administration of antimicrobials remains an effective way to control weaning diarrhoea but it remains unclear how they affect gut physiology and microbiology although this is a prerequisite for being able to devise better alternatives. Hence, for 7 d we treated pigs, weaned at 24 d of age, with a combination of amoxicillin (25 mg/kg feed and injection of 8·75 mg/kg body weight per 12 h) and ZnO (2·5 g/kg feed). The pigs treated with antimicrobials (n11) showed no signs of gut malfunction at any time, whereas untreated weaned controls (n11) developed clinical diarrhoea. The antimicrobial treatment resulted in a higher daily weight gain compared with weaned controls (101v. − 44 g/d,P < 0·0001), whereas both groups had a similar degree of villous atrophy compared with unweaned 24-d-old controls (n8;P < 0·05). The antimicrobial treatment gave a dramatic reduction in small intestinal microbial diversity, and specifically prevented tissue colonization withEscherichia colicompared with weaned controls. Further, the antimicrobial treatment improved amylase, trypsin and small intestinal aminopeptidase A and N activities (allP < 0·05). Specifically for the colon, the antimicrobial treatment was associated with reduced tissue weight ( − 23 %,P < 0·05), reduced concentration of SCFA (P < 0·05), and increased mucosal goblet cell area (P < 0·0001) compared with weaned controls. We conclude that the beneficial effects of antimicrobials are mediated not only through reduction in intestinal bacterial load, but also through a stimulation of protein digestive function and goblet cell density.
Childhood malnutrition is associated with a reduction in the total melanin content of scalp hair
Authors: McKenzie Colin A. , Wakamatsu Kazumasa , Hanchard Neil A. , Forrester Terrence , Ito Shosuke
Published: March 2007

Childhood malnutrition is known to be associated with visible lightening of hair colour (hypochromotrichia). Nevertheless, no systematic investigations have been carried out to determine the biochemical basis of this change. We used an HPLC method to measure melanins in the scalp hair of thirteen Jamaican children, diagnosed as having primary malnutrition, during various stages of their treatment and after recovery. During treatment for malnutrition, a progressive decrease in total melanin content along the hair shaft from tip to root (root:tip ratio: 0·62 (sd 0·31)) was observed. This ratio was significantly different (P = 0·003) from the ratio observed among children sampled several months after discharge from hospital (0·93 (sd 0·23)) and among normal control children (0·97 (sd 0·12)). Thus, it appears that a decrease in melanin content is associated with periods of malnutrition. The low root:tip ratio during malnutrition presumably arises because the tips reflect prior hair growth during ‘normal’ nutrition and the roots reflect hair growth during malnutrition; a return of the root:tip ratio to that seen among controls reflects ‘recovery’ from malnutrition. It is possible that reduced intake or availability of tyrosine, a key substrate in melanin synthesis, may play a role in the reduction of hair melanin content during periods of malnutrition. The precise mechanisms by which melanin content is reduced, and the role of aromatic amino acid availability in hair colour change and other features of childhood malnutrition remain to be explored.
Carob pulp preparation rich in insoluble dietary fibre and polyphenols increases plasma glucose and serum insulin responses in combination with a glucose load in humans
Authors: Gruendel Sindy , Otto Baerbel , Garcia Ada L. , Wagner Karen , Mueller Corinna , Weickert Martin O. , Heldwein Walter , Koebnick Corinna
Published: March 2007

Dietary fibre consumption is associated with improved glucose homeostasis. In contrast, dietary polyphenols have been suggested to exert both beneficial and detrimental effects on glucose and insulin metabolism. Recently, we reported that a polyphenol-rich insoluble dietary fibre preparation from carob pulp (carob fibre) resulted in lower postprandial acylated ghrelin levels after a liquid meal challenge test compared with a control meal without supplementation. The effects may, however, differ when a different food matrix is used. Thus, we investigated the effects of carob fibre on glucose, insulin and ghrelin responses in healthy humans in combination with a glucose load. In a randomized single-blind cross-over study involving twenty healthy subjects (aged 22–62 years), plasma glucose, total and acylated ghrelin, and serum insulin were repeatedly assessed before and after the ingestion of 200 ml water with 50 g glucose and 0, 5, 10 or 20 g carob fibre over a period of 180 min. The intake of 5 and 10 g carob fibre increased the plasma glucose by 47 % and 64 % (P < 0·001), and serum insulin by 19·9 and 24·8 % (P < 0·001), compared with the control. Plasma acylated ghrelin concentrations did not change significantly after the consumption of carob-enriched glucose solution. Total ghrelin decreased only after 10 g carob fibre (P < 0·001) compared with control. In conclusion, we showed that polyphenol-rich carob fibre, administered within a water–glucose solution, increases postprandial glucose and insulin responses, suggesting a deterioration in glycaemic control.
The Engine or the Caboose? Resource Industries and Twentieth-Century Canadian Economic Performance
Authors: Keay Ian
Published: March 2007

The Canadian economy, already wealthy, diverse, and relatively industrial at the dawn of the twentieth century, had not yet outgrown its reliance on resource-intensive production. Empirical evidence indicates that the exploitation of Canada's natural resource endowment made direct and indirect contributions to the size and efficiency of the twentieth-century domestic economy. I conclude that the concentration of capital and labor in resource industries did not constrain the rate of change of Canadian real GNP per capita between 1900 and 1999, and it appears to have had a substantial positive impact on the level of real GNP per capita.
Two Centuries of Productivity Growth in Computing
Authors: Nordhaus William D.
Published: March 2007

The present study analyzes computer performance over the last century and a half. Three results stand out. First, there has been a phenomenal increase in computer power over the twentieth century. Depending upon the standard used, computer performance has improved since manual computing by a factor between 1.7 trillion and 76 trillion. Second, there was a major break in the trend around World War II. Third, this study develops estimates of the growth in computer power relying on performance rather than components; the price declines using performance-based measures are markedly larger than those reported in the official statistics.
Slave Purchasing Strategies and Shipboard Mortality: Day-to-Day Evidence from the Dutch African Trade, 1751–1797
Authors: Hogerzeil Simon J. , Richardson David
Published: March 2007

The mortality of enslaved Africans in the Atlantic crossing has long preoccupied historians but the relationship between slave traders' purchasing strategies and slave mortality rates in transit has escaped close investigation. We address these issues by using records of 39 eighteenth-century voyages of the Dutch Middelburgsche Commercie Compagnie. These allow shipboard mortality rates of enslaved Africans to be estimated. They also reveal previously un-noticed age- and gender-based variations in slave purchase and mortality patterns, which in turn shed light on the relative importance of African and shipboard conditions in determining slave survival rates in the middle passage.
Emergence of Endogenous Legal Institutions: Property Rights and Community Governance in the Italian Alps
Authors: Casari Marco
Published: March 2007

This article examines changes in institutions that protected property rights in the Alps between the thirteenth and the nineteenth century and, in particular, alternative management systems adopted for the common pastures and forests in about 200 communities. Over time, private-order institutions in the form of charters replaced informal arrangements sustained by the long-run interaction among villagers. Although costly to run, the charters accomplished several tasks that increased resource use efficiency.
Cultivation and the loss of rice landraces in the Terai region of Nepal
Authors: Joshi Ganesh R. , Bauer Siegfried
Published: March 2007

Landraces (LRs) are important as a source of novel alleles for crop improvement, and their conservation is therefore necessary for food security. These genetic resources have suffered continuous erosion, especially in more accessible areas. We assess the loss of Nepali rice LRs and identify the factors influencing the probability of cultivating the most dominant LR via a logistic regression model. The majority of farmers cultivate LRs and modern varieties simultaneously. However, there has been a decrease in varietal diversity and a loss of some LRs over recent years, mainly because of their low yield, their sensitivity to diseases and pests, and their late maturity. The opportunity cost of maintaining the Satha landrace is higher on irrigated farms and for those farmers specializing in niche products. On the other hand, Satha is more likely to be cultivated by large-scale farmers and by those having a religious and/or a cultural attachment to this LR. Market-based incentives are less costly than publicly funded conservation programmes, and the superior taste of some LRs may allow them to be developed as niche products. However, to achieve this, public investment is needed to generate the necessary support infrastructure. In the more accessible Terai region, there is a particular need to introduce a flexible incentive mechanism to maintain LRs and to offset the negative effect of development intervention.
Implications for in situ genetic resource conservation from the ecogeographical distribution of rice genetic diversity in Maritime Guinea
Authors: Barry M. B. , Pham J. L. , Noyer J. L. , Courtois B. , Billot C. , Ahmadi N.
Published: March 2007

Genetic resource conservation is widely acknowledged as important. The implementation of conservation requires an insight into the distribution of genetic diversity at the scale of small regions or villages. We present an analysis of rice diversity at such a scale, in a region where traditional farming still prevails. Regional allelic diversity was comparable to that noted worldwide for Asian rice (Oryza sativa), but not as high for African rice (O. glaberrima). Each village pooled more than half of the regional allelic diversity. Genetic differentiation between varieties from the same village accounted for 70% of the regional variation. The differentiation associated with lowland and upland rice-growing ecosystems was 23%, while that associated with differences between villages within the same ecosystem was 7%. In the upland ecosystem, geographical distance had a significant effect on theFSTbetween pairs of villages. In the lowland ecosystem, differences in soil salinity between villages affectedFST. Genetic diversity within a single village may have up to three components: an ancientglaberrimacomponent shared with neighbouring or ethnically related villages; a relatively ancientsativacomponent which was hardly or no longer shared with other villages due to local differentiation; and a recently introducedsativacomponent shared with other villages. Genetic resource conservation could be achieved, in terms of allelic diversity, through stratified sampling according to described genetic differentiation factors, whereas current farming systems must be preserved to ensure conservation of the diversity of allelic associations.
Essential oil composition and antimicrobial assay of Acorus calamus leaves from different wild populations
Authors: Radušienė J. , Judžentienė A. , Pečiulytė D. , Janulis V.
Published: March 2007

The composition of essential oils obtained from leaves ofAcorus calamusgrowing wild in 19 different locations was analysed by gas chromatography and gas chromatography–mass spectrometry. In total, 84 constituents have been identified, representing at least 86% of the total essential oil. The essential oils were dominated by the presence of phenolic compounds: (Z)-asarone (15.7–25.5%) and (Z)-methyl isoeugenol (2.0–4.9%). Other identified major components were (E)-caryophyllene, α-humulene, germacrene, linalool, camphor and isoborneol. All oils were found to have a similar composition. However, a hierarchical cluster analysis of the quantitative data revealed significant differences between some accessions. Minimal inhibitory concentrations (MIC) of four selected leaf essential oils were determined by a screening test with the broth dilution method. Of the 17 species of fungi, bacteria and yeasts tested,Mycobacteriumssp. andBacillus subtiliswere most susceptible to essential oils. Oils displayed low anti-fungal activity and their inhibitory activity was lower than the standard antibiotics. Oils differed in their activities against the various microorganisms tested.
An Approach for Increasing the Mass Recovery of Proteins Derived from Inclusion Bodies in Biotechnology
Authors: Wu Dan , Wang Chaozhan , Geng Xindu
Published: March 2007

A method for increasing the mass recovery of therapeutic proteins produced by E. coli using liquid chromatography was investigated. Recombinant human interferon‐γ (rhIFN‐γ) produced by E. coli was selected as a model therapeutic protein, and hydrophobic interaction chromatography (HIC) was performed as a model for liquid chromatography. Using seven types of stationary phase hydrophobic interaction chromatography (STHIC) with different end groups, the effect of the stationary phase on the mass recovery during protein folding by liquid chromatography (LC) and the causes of mass loss of rhIFN‐γ during its folding with simultaneous purification were investigated. Also strategies for increasing mass recovery are proposed. The results demonstrate that the mass recovery of rhIFN‐γ increases with the decreasing hydrophobicity for six STHIC with end groups of PEG‐200, PEG‐400, PEG‐600, PEG‐1000, furfural, and phenyl, except for PEG‐1000. However, for oxethyl and PEG‐600, even though the same diol end group is bonded to PEG‐600, so long as the PEG‐600 is modified by acetyl chloride, it can effectively enhance the mass and bioactivity recovery of rhIFN‐γ compared to the PEG‐600 column. The effect of sample size including both mass and volume on the mass recovery of the rhIFN‐γ was also investigated. Last, redissolving the target protein that has irreversibly adsorbed to the stationary phase and re‐injecting it onto the column is an approach for increasing mass recovery.
Flux Balance Analysis of a Genome‐Scale Yeast Model Constrained by Exometabolomic Data Allows Metabolic System Identification of Genetically Different Strains
Authors: Çakır Tunahan , Efe Çaǧrı , Dikicioǧlu Duygu , Hortaçsu Amable , Kırdar Betül , Oliver Stephen G.
Published: March 2007

A systems approach to biology requires a principled approach to pathway identification. In this study, the two nuclear petite yeast mutants K1Δpet191a and K1Δpet191ab and their parental industrial strain K1 were cultured in glucose‐containing microaerobic chemostats. Exometabolomic profiles were used to infer the differences in the fermentation characteristics and respiration capacity of the strains. The ability of the metabolite measurement information to describe genetically different strains was investigated using a genome‐scale yeast model. Flux balance analysis (FBA) of the model reveals that the objective function of minimal oxygen consumption enables the identification of the effect of genotypic differences when combined with the knowledge of the extracellular state of metabolism. The predicted decrease in oxygen consumption flux of K1Δpet191a and K1Δpet191ab strains with respect to the parental strain is about 80% and 100%, respectively, which coincides with the respiratory deficiencies of the strains. The expected increase in ethanol production rates in response to the decrease in the respiratory capacity was also predicted to be very close to the experimental values. This study shows the predictive power of the integrated analysis of genome‐scale models with exometabolomic profiles, since accurate predictions could be made without any information about the respiration capacity of the strains. The FBA approach thereby enables identification of responsive pathways and so permits the elucidation of the genetic characteristics of strains in terms of expressed metabolite profiles.
Therapeutische Anwendung von Musik und Entspannungsanleitung bei Patienten mit Schmerzen und von Musik allein bei Patienten mit Morbus Parkinson
Authors: Bernatzky Günther , Wendtner Franz , Bernatzky Patrick , Kullich Werner , Likar Rudolf
Published: March 2007

Zusammenfassung. Schmerz stellt einerseits eine große Belastung für die Patienten dar, andererseits sind dadurch höhere Kosten und u.U. längere Krankenhausaufenthalte der Fall. Schmerz ist immer subjektiv und wird individuell unterschiedlich erlebt. Psychische Faktoren, wie Hilflosigkeit, Angst, Depression usw. steigern die Wirkung von Schmerz als physiologischen Stressor und haben Einfluss auf die Schmerzstärke. Ängste, Verspannungen und Herabsetzung der Schlafqualität mindern das Wohlbefinden und verzögern den Genesungsprozess. Musik in Kombination mit einer gesprochenen Entspannungsanleitung kann über den Einfluss auf affektive, kognitive und sensorische Vorgänge eine maßgebliche schmerzhemmende Wirkung entfalten. Ziel der vorliegenden Studie ist es, den Effekt einer standardisierten Musik in Kombination mit einer gesprochenen Entspannungsanleitung, bei chronischen Rückenschmerzpatienten zu evaluieren. Gleichzeitig wird in diesem Beitrag gezeigt, welche Wirkung eine stimulierende Musik bei Patienten mit Morbus Parkinson hat.
Gesundheitsrelevantes Verhalten, Delinquenz und Sportpartizipation im Jugendalter
Authors: Raithel Jürgen
Published: March 2007

Zusammenfassung. Gegenstand des Beitrags ist vor dem Hintergrund eines stresstheoretischen Sozialisationsmodells einmal der Vergleich von sportengagierten zu sportabstinenten Jugendlichen und zum zweiten der Vergleich zwischen Individual- und Mannschaftssportlern anhand unterschiedlichster gesundheitsrelevanter und delinquenter Verhaltensweisen sowie stresstheoretisch bedeutsamer Ressourcen. Datengrundlage bilden Aussagen von 602 Jugendlichen zwischen 15 und 18 Jahren, die anhand eines standardisierten Erhebungsinstruments schriftlich befragt wurden. Die Datenauswertung erfolgte über Mittelwertsvergleiche, multiple Regressionsanalysen und einem Strukturgleichungsmodell. Die Befunde weisen ein suppressives Potential der Sportpartizipation gegenüber dem Alkohol- und Zigarettenkonsum, dem Diebstahl sowie einen förderlichen Effekt bezüglich Ernährungs- und Zahnpflegeverhalten aus. Für die Ressource der sozialen Unterstützung zeigt sich ein ambivalentes Bild. Der Sportartenvergleich führt zu einer günstigeren Bilanz auf Seiten der Individualsportler.
A stochastic nonparametric technique for space‐time disaggregation of streamflows
Authors: Prairie James , Rajagopalan Balaji , Lall Upmanu , Fulp Terrance
Published: March 2007

Stochastic disaggregation models are used to simulate streamflows at multiple sites preserving their temporal and spatial dependencies. Traditional approaches to this problem involve transforming the streamflow data of each month and at every location to a Gaussian structure and subsequently fitting a linear model in the transformed space. The simulations are then back transformed to the original space. The main drawbacks of this approach are (1) transforming marginals to Gaussian need not lead to the correct multivariate distribution particularly if the dependence across variables is nonlinear, and (2) the number of parameters to be estimated for a traditional disaggregation model grows rapidly with an increase in space or time components. We present a K‐nearest‐neighbor approach to resample monthly flows conditioned on an annual value in a temporal disaggregation or multiple upstream locations conditioned on a downstream location for a spatial disaggregation. The method is parsimonious, as the only parameter to estimate is K (the number of nearest neighbors to be used in resampling). Simulating space‐time flow scenarios conditioned upon large‐scale climate information (e.g., El Niño–Southern Oscillation, etc.) can be easily achieved. We demonstrate the utility of this methodology by applying it for space‐time disaggregation of streamflows in the Upper Colorado River basin. The method appropriately captures the distributional and spatial dependency properties at all the locations.
Teleconnections between ENSO and North Atlantic in an ECHO‐G simulation of the 1000–1990 period
Authors: Gouirand Isabelle , Moron Vincent , Zorita Eduardo
Published: March 2007

The North Atlantic sea level pressure anomalies (SLPA) associated with El Niño Southern Oscillation (ENSO) have been analyzed in a quasi‐millennial (1000–1990) simulation with the ECHO‐G model. In November–December, the ENSO‐related SLPA over the North Atlantic area are weak, while a realistic pattern already appears over the North Pacific and North America. In January–March, the SLPA over North Atlantic are stronger and realistic from the North Pacific to Europe: the Aleutian low is strengthened (weakened), SLPA are positive (negative) over the north‐central and north‐eastern parts of North America, and SLPA display a negative (positive) NAO‐like pattern over North‐Atlantic during warm (cold) ENSO events, as in observations. The results also confirm the existence of a strong inter‐event SLPA associated with warm and cold ENSO events, especially over the North Atlantic, while the relationship is stationary at multidecadal timescales. It seems that neither the intensity nor geographical longitude of the equatorial Pacific sea surface temperature anomaly (SSTA) and intensity of tropical Atlantic SSTA, nor the volcanic forcing, simply introduced here as a decrease of the solar constant, significantly induce an inter‐event variability, which seems, in this run, mostly of atmospheric origin.
Plate coupling variation and block translation in the Andreanof segment of the Aleutian arc determined by subduction zone modeling using GPS data
Authors: Cross Ryan S. , Freymueller Jeffrey T.
Published: March 2007

We use GPS measurements in the first geodetic study of plate coupling on the Andreanof segment, Aleutian subduction zone. Convergence of 7.3 cm/yr at the subduction zone results in northwestward displacements greater than 1 cm/yr at stations located on the west end of the Andreanof region, but velocities at the east end are smaller in magnitude and oriented west‐southwest. These velocity variations are caused by differences in plate coupling along the subduction zone, which correlate with the rupture zones of the 1986 and 1996 Mw8 earthquakes. We construct a dislocation model to estimate the velocity of the arc in the Andreanof region relative to North America, and fault plane coupling coefficients. Our best model shows a southwestward velocity of 7.8 mm/yr, a high degree of coupling in the main thrust zone at the west end of the subduction zone, and little to no coupling at the east end.
Contribution of land‐atmosphere coupling to recent European summer heat waves
Authors: Fischer E. M. , Seneviratne S. I. , Lüthi D. , Schär C.
Published: March 2007

Most of the recent European summer heat waves have been preceded by a pronounced spring precipitation deficit. The lack of precipitation and the associated depletion of soil moisture result in reduced latent cooling and thereby amplify the summer temperature extremes. In order to quantify the contribution of land‐atmosphere interactions, we conduct regional climate simulations with and without land‐atmosphere coupling for four selected major summer heat waves in 1976, 1994, 2003, and 2005. The coupled simulation uses a fully coupled land‐surface model, while in the uncoupled simulation the mean seasonal cycle of soil moisture is prescribed. The experiments reveal that land‐atmosphere coupling plays an important role for the evolution of the investigated heat waves both through local and remote effects. During all simulated events soil moisture‐temperature interactions increase the heat wave duration and account for typically 50–80% of the number of hot summer days. The largest impact is found for daily maximum temperatures during heat wave episodes.
Global Kelvin waves in the upper atmosphere excited by tropospheric forcing at midlatitudes
Authors: Salby Murry L. , Matrosova Ludmila , Callaghan Patrick F.
Published: March 2007

Nonlinear integrations with a 3‐D primitive equation model of the middle and upper atmosphere reveal global‐scale Kelvin waves. Owing to their meridional extent, these eastward propagating disturbances can be excited by tropospheric fluctuations over much of the globe. Stochastic forcing in the midlatitude troposphere produces an eastward response that involves the Kelvin normal mode, with barotropic vertical structure, as well as a continuum of vertically propagating Kelvin waves. Having periods of order a day and shorter, those disturbances are all global. Transient fluctuations representative of midlatitude weather systems reproduce observed Kelvin structure and amplitude near the tropopause. Vertical amplification then leads to wind fluctuations at mesospheric and thermospheric altitudes of 5–15 m/s. Approaching tidal amplitudes, global Kelvin waves should therefore represent a measurable if not prominent feature at those altitudes.
Climatology of low‐latitude mesospheric echo characteristics observed by Indian mesosphere, stratosphere, and troposphere radar
Authors: Kumar G. Kishore , Ratnam M. Venkat , Patra A. K. , Rao V. V. M. Jagannadha , Rao S. Vijaya Bhaskara , Rao D. Narayana
Published: March 2007

Low‐latitude mesospheric echo characteristics are investigated using data collected during June 1994 to July 2005 (11 years) by the Indian mesosphere, stratosphere, and troposphere radar located at Gadanki (13.5°N, 79.2°E). Mesospheric echoes are frequently observed during 1000–1530 hrs (local time) in the height range of 68–78 km and are found to be highly intermittent in both space and time, consistent with those reported elsewhere. Although echoes are observed throughout the year, strong seasonal dependence has been observed in both echo occurrence and signal‐to‐noise ratio (SNR). Percentage occurrence (PO) of mesospheric echoes shows two maxima, one during late March equinox and early summer, and another during September. However, corresponding SNR suggests that strong echoes occur in both equinoxes with a minimum during winter. A clear semiannual variation is observed in PO of echoes with a peak occurring during the months of May and October. Similar variation is observed in SNR with peaks in March and September–November. These features are quite different from those observed at midlatitudes and high latitudes. Annual oscillation seems to fit well above 78 km and below 68 km, although on many occasions, occurrence of echo is poor at these heights. The ratio of vertical to off‐vertical beam SNR (which could be taken as a measure of aspect sensitivity) was close to unity at these heights, indicating that scattering is due to turbulence‐generated refractive index fluctuations. A positive correlation (R = 0.37) between PO and solar activity is observed, whereas a negative correlation (R = −0.55) is found between SNR and solar activity. The echo characteristics observed have been compared in detail with those reported from midlatitudes and high latitudes. The mechanisms behind the observed features are discussed in the light of mesospheric temperature inversions (MTIs), which are often noticed at this location, and wave breaking at these altitudes.
Bay of Bengal summer monsoon 10–20 day variability in sea surface temperature using model and observations
Authors: Agarwal Neeraj , Sharma Rashmi , Basu Sujit , Parekh Anant , Sarkar Abhijit , Agarwal Vijay K.
Published: March 2007

Observed sea surface temperature (SST) in the Bay of Bengal exhibits intraseasonal variability during summer monsoon. An ocean general circulation model (OGCM) driven by satellite derived daily winds and heat fluxes during summer of 2000 is able to reproduce aspects of intraseasonal variability (10–20 days) in SST. The intra‐seasonal SST simulated using satellite derived shortwave flux compares more favorably with buoy data than that produced using the NCEP reanalysis flux. Analysis of the terms in the heat balance equation of MLD suggests that in the central Bay of Bengal local net heat flux and vertical diffusive mixing changes drive the SST ISOs. Thus, the SST ISOs in this region are governed primarily by one‐dimensional processes.
Automated Three-Dimensional Analysis of Histological and Autoradiographic Rat Brain Sections: Application to an Activation Study
Authors: Dubois Albertine , Dauguet Julien , Herard Anne-Sophie , Besret Laurent , Duchesnay Edouard , Frouin Vincent , Hantraye Philippe , Bonvento Gilles , Delzescaux Thierry
Published: March 2007

Besides the newly developed positron emission tomography scanners (microPET) dedicated to the in vivo functional study of small animals, autoradiography remains the reference technique widely used for functional brain imaging and the gold standard for the validation of in vivo results. The analysis of autoradiographic data is classically achieved in two dimensions (2D) using a section-by-section approach, is often limited to few sections and the delineation of the regions of interest to be analysed is directly performed on autoradiographic sections. In addition, such approach of analysis does not accommodate the possible anatomical shifts linked to dissymmetry associated with the sectioning process. This classic analysis is time-consuming, operator-dependent and can therefore lead to non-objective and non-reproducible results. In this paper, we have developed an automated and generic toolbox for processing of autoradiographic and corresponding histological rat brain sections based on a three-step approach, which involves: (1) an optimized digitization dealing with hundreds of autoradiographic and histological sections; (2) a robust reconstruction of the volumes based on a reliable registration method; and (3) an original 3D-geometry-based approach to analysis of anatomical and functional post-mortem data. The integration of the toolbox under a unified environment (in-house software BrainVISA, http://brainvisa.info ) with a graphic interface enabled a robust and operator-independent exploitation of the overall anatomical and functional information. We illustrated the substantial qualitative and quantitative benefits obtained by applying our methodology to an activation study (rats, n = 5, under unilateral visual stimulation).
Transient Hypertension Concurrent with Forepaw Stimulation Enhances Functional MRI Responsiveness in Infarct and Peri-Infarct Regions
Authors: Tuor Ursula I , Wang Rong , Zhao Zonghang , Foniok Tadeusz , Rushforth David , Wamsteeker Jaclyn I , Qiao Min
Published: March 2007

Although functional magnetic resonance imaging (fMRI) is gaining use as a tool to assess cerebral recovery following various insults, the effects of potential confounders such as hypertension are poorly defined. We hypothesized that after stroke, transient hypertension during an fMRI study could produce a detected activation unrelated to neuronal activity within the infarct. Thus, the effect of norepinephrine induced increases in blood pressure (BP) on the fMRI response to forepaw stimulation were investigated in controls or 1 week after transient middle cerebral artery occlusion in rats. Images were smoothed spatially and voxels correlating to either forepaw stimulation or the change in BP time courses were analyzed. Transient hypertension increased the signal intensity and numbers of voxels correlating to the BP time courses within and adjacent to the ischemic infarct and these exceeded the response in the contralateral hemisphere or in controls. With left paw stimulation at normotension, there was a loss of activation in right sensory—motor cortex—a region with necrosis and disruption of cerebral vessels. As BP increased left paw stimulation also resulted in the detection of activation in the infarcted sensory—motor cortex and peri-infarct regions. Thus, BP changes synchronous with tasks in fMRI studies can result in MR signal changes consistent with a loss of cerebral blood flow (CBF) autoregulation rather than neuronal activation in necrotic brain. After stroke, the use of stressful tasks associated with BP changes in fMRI studies should be limited or the BP change should be considered as a potential source of MR signal changes.
Spectacular Shrinking Deficit: Insights from Multimodal Magnetic Resonance Imaging after Embolic Middle Cerebral Artery Occlusion in Sprague—Dawley Rats
Authors: Henninger Nils , Sicard Kenneth M , Fisher Marc
Published: March 2007

Almost no data is available on the serial changes in the brain after spectacular shrinking deficit (SSD) that may help understand this relatively rare clinical phenomenon. Quantitative diffusion-(DWI), perfusion-(PWI), T1-(T1WI), T2-weighted (T2WI), and functional magnetic resonance imaging (fMRI) were performed before, during, and up to 7 days after embolic middle cerebral artery occlusion (eMCAO) in male Sprague—Dawley rats ( n = 9). Region of interest (ROI) analysis was used to evaluate structural and functional MR signal changes within three ROIs defined by the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) signatures, and final tissue viability. DWI, PWI, and T2WI lesion volumes were calculated using previously established viability thresholds and final infarct volumes ascertained with 2,3,5-triphenyltetrazolium chloride (TTC) staining. Serial MRI demonstrated spontaneous reperfusion of initially hypoperfused MCA regions accompanied by substantial reduction of initial ADC and CBF lesions and gradual recovery of neurological outcome. Recovery rates of CBF/ADC abnormalities differed among ROIs. Functional magnetic resonance imaging showed persistent tissue dysfunction after the recovery of the CBF/ADC lesions. This study may facilitate our understanding of the pathophysiological mechanisms by which early, spontaneous reperfusion affects tissue fate and neurological function.
The PI3K p110δ controls T-cell development, differentiation and regulation
Authors: Patton D.T. , Garçon F. , Okkenhaug K.
Published: March 2007

PI3Ks (phosphoinositide 3-kinases) regulate diverse cellular functions such as metabolism, growth, gene expression and migration. The p110δ isoform of PI3K is mainly expressed in cells of the immune system and contributes to cellular and humoral immunity. In the thymus, p110δ and p110γ play complementary roles in regulating the transition through key developmental checkpoints. In addition, p110δ regulates the differentiation of peripheral Th (helper T-cells) towards the Th1 and Th2 lineages. Moreover, p110δ is critical for Treg (regulatory T-cell) function. Here, we review the role of PI3Ks in T-cell development and function.
Role of PTEN/PI3K pathway in endothelial cells
Authors: Suzuki A. , Hamada K. , Sasaki T. , Mak T.W. , Nakano T.
Published: March 2007

PTEN (phosphatase and tensin homologue deleted on chromosome 10) is an important tumour-suppressor gene that encodes a 3-phosphatase. The major substrate of PTEN is PIP3 (phosphatidylinositol 3,4,5-trisphosphate) generated by the action of PI3Ks (phosphoinositide 3-kinases). Hereditary mutation of PTEN causes tumour-susceptibility diseases such as Cowden disease. We used the Cre-loxP system to generate an endothelial cell-specific mutation of PTEN in mice. Heterozygous mutation of PTEN in endothelial cells enhances postnatal neovascularization, including tumour angiogenesis necessary for tumour growth. This observation suggests that Cowden disease patients are not only at risk for additional tumorigenic mutations due to complete loss of PTEN function, but may also experience accelerated growth of incipient tumours due to enhanced angiogenesis. Homozygous mutation of Pten in murine endothelial cells impairs cardiovascular morphogenesis and is embryonic lethal due to endothelial cell hyperproliferation and impaired vascular remodelling. Additional homozygous mutation of p85α, the regulatory subunit of class IA PI3Ks, or p110γ, the catalytic subunit of the sole class IB PI3K, led to a partial rescue of all phenotypes in our PTEN-deficient mice. Thus inhibition of the PI3K pathway, including the targeting of PI3Kγ, may be an attractive therapeutic strategy for the treatment of various malignancies.
p110δ is required for innate immunity to transplantable lymphomas
Authors: Saudemont A. , Okkenhaug K. , Colucci F.
Published: March 2007

NK cell (natural killer cells) are lymphocytes of innate immunity that kill tumour cells and respond to infections, without prior stimulation. A balance of activating and inhibitory signals regulates NK cell cytotoxicity, but the molecular mechanisms are not fully understood. General inhibitors of PI3K (phosphoinositide 3-kinase) suppress cytotoxicity in human and mouse NK cells. However, which isoforms and how they regulate NK cell activation is unknown, and no data have been published on mice carrying PI3K mutations. p110δ expression is restricted to leucocytes, where it plays central roles in lymphocyte development and signalling. We have used mice carrying a catalytically inactive mutant form of p110δ in order to determine its role in NK cell biology. We show here that p110δ is not required to kill tumour cells, but unexpectedly p110δ mutant mice failed to fully reject transplanted lymphomas. Our results show for the first time a critical role for p110δ in NK cell biology in vivo.
Phosphoinositide 3-kinase signalling events controlling axonal morphogenesis
Authors: Cosker K.E. , Eickholt B.J.
Published: March 2007

The establishment of neuronal morphology is essential for the formation of the nervous system. In general, neurons undergo a developmental programme during which their immature processes are specified into one axon and several dendrites. Extension of axons and dendrites is then critical for the establishment of appropriate connectivity. A body of work implicates the PI3K (phosphoinositide 3-kinase) signalling pathway to be crucial during the various events leading to the formation of neuronal circuit. In this review, we will focus specifically on the function of PI3K and downstream signalling cascades that control the establishment of axonal specification and elongation.