bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipopolysaccharide activated phosphatidylcholine‐specific phospholipase C and induced IL‐8 and MCP‐1 production in vascular endothelial cells
Authors: Zhang Lu , Li Hai Ying , Li Hui , Zhao Jing , Su Le , Zhang Yun , Zhang Shang Li , Miao Jun Ying
Published: November 2010

Secretion of proinflammatory cytokines by lipopolysaccharide (LPS) activated vascular endothelial cells (VECs) contributes substantially to the pathogenesis of several inflammatory diseases such as atherosclerosis and septic shock. However, the mechanisms involved in this process are not well understood. Here, we investigated the role of phosphatidylcholine‐specific phospholipase C (PC‐PLC) in LPS‐induced IL‐8 and MCP‐1 production in VECs. The results showed that LPS elevated the level of PC‐PLC and the production of IL‐8 and MCP‐1 in Human umbilical vein vascular endothelial cells (HUVECs). Blocking the function of PC‐PLC by exploiting the neutralization antibody of PC‐PLC or tricyclodecan‐9‐yl‐xanthogenate (D609), an inhibitor of PC‐PLC, significantly inhibited LPS‐induced production of IL‐8 and MCP‐1 in HUVECs. Furthermore, the in vivo experimental results showed that the levels of PC‐PLC, IL‐8, and MCP‐1 in the aortic endothelium and serum were increased in mice injected with LPS. The increased levels of these molecules were also inhibited by the treatment with D609. The data suggested that blocking PC‐PLC function significantly inhibited LPS‐induced IL‐8 and MCP‐1 production in cultured HUVECs and in vivo. PC‐PLC might be a potential target for therapy in inflammation associated‐diseases such as atherosclerosis. J. Cell. Physiol. 226: 1694–1701, 2011. © 2010 Wiley‐Liss, Inc.
Morphology and ultrastructure of the nephridial system of Hypania invalida (Grube, 1860) (Annelida, Polychaeta, Ampharetidae)
Authors: Kremer Philipp , Fiege Dieter , Wehe Thomas
Published: November 2010

The excretory organs of the freshwater polychaete Hypania invalida have been examined using scanning and transmission electron microscopy. Three pairs of macroscopically and ultrastructurally different nephridia are present in the thorax. Intersegmental septa in the thorax are absent, with the exception of a single diaphragm between second and third chaetiger. The first pair of nephridia is anterior to this septum, the second pair crosses the septum, with the nephrostomes anterior and the ducts and the nephridiopori posterior to it, and the third pair of nephridia is entirely posterior to the diaphragm. The first two pairs of nephridia have ciliated nephrostomes of moderate size and long nephridial ducts that extend the length of the thorax. In contrast, the third pair is characterized by short ducts and very prominent nephrostomes. Macroscopically, seven different sections of nephridial duct cells can be distinguished along the length of the first two pairs of nephridia, whereas, on an ultrastructural basis, only six different regions can be identified. Only two regions of different duct cells can be recognized in the third pair of nephridia. Cells of the two anterior pairs of nephridia show typical characteristics of transport epithelia and most likely function as excretory organs. In contrast, the duct cells of the third pair are not that much differentiated and might primarily be responsible for the release of sexual products, as sperm was observed passing through these ducts. Podocyte‐like cells were observed to accompany nephridial ducts. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc.
Serum insulin‐like system alterations in patients with spinocerebellar ataxia type 3
Authors: Saute Jonas Alex Morales , da Silva Andrew Chaves Feitosa , Muller Alexandre Pastoris , Hansel Gisele , de Mello Alexandre Silva , Maeda Fábio , Vedolin Leonardo , Saraiva‐Pereira Maria Luiza , Souza Diogo Onofre , Arpa Javier , Torres‐Aleman Ignacio , Portela Luis Valmor Cruz , Jardim Laura Bannach
Published: November 2010

Spinocerebellar ataxias (SCAs) constitute a group of autosomal dominant neurodegenerative disorders with no current treatment. The insulin/insulin‐like growth factor 1 (IGF‐1) system (IIS) has been shown to play a role in the neurological dysfunction of SCAs and other polyglutamine disorders. We aimed to study the biomarker profile of serum IIS components in SCA3. We performed a case–control study with 46 SCA3 patients and 42 healthy individuals evaluating the peripheral IIS profile (insulin, IGF‐1, IGFBP1 and 3) and the correlation with clinical, molecular, and neuroimaging findings. SCA3 patients presented lower insulin and IGFBP3 levels and higher insulin sensitivity (HOMA2), free IGF‐I, and IGFBP1 levels when compared with controls. IGFBP‐1 levels were directly associated with CAG expanded repeat length; IGF‐1 was associated with the volumetries of specific brainstem regions on magnetic resonance imaging (MRI). Insulin levels and sensitivity were related to age at onset of symptoms. Our findings indicate an involvement of IIS components in SCA3 neurobiology and IGFBP‐1 as a potential biomarker of the disease. © 2010 Movement Disorder Society
Epoetin alfa increases frataxin production in Friedreich's ataxia without affecting hematocrit
Authors: Saccà Francesco , Piro Raffaele , De Michele Giuseppe , Acquaviva Fabio , Antenora Antonella , Carlomagno Guido , Cocozza Sergio , Denaro Alessandra , Guacci Anna , Marsili Angela , Perrotta Gaetano , Puorro Giorgia , Cittadini Antonio , Filla Alessandro
Published: November 2010

Objective of the study was to test the efficacy, safety, and tolerability of two single doses of Epoetin alfa in patients with Friedreich's ataxia. Ten patients were treated subcutaneously with 600 IU/kg for the first dose, and 3 months later with 1200 IU/kg. Epoetin alfa had no acute effect on frataxin, whereas a delayed and sustained increase in frataxin was evident at 3 months after the first dose (+35%; P < 0.05), and up to 6 months after the second dose (+54%; P < 0.001). The treatment was well tolerated and did not affect hematocrit, cardiac function, and neurological scale. Single high dose of Epoetin alfa can produce a considerably larger and sustained effect when compared with low doses and repeated administration schemes previously adopted. In addition, no hemoglobin increase was observed, and none of our patients required phlebotomy, indicating lack of erythropoietic effect of single high dose of erythropoietin. © 2010 Movement Disorder Society
LMP1 antagonizes WNT/β‐catenin signalling through inhibition of WTX and promotes nasopharyngeal dysplasia but not tumourigenesis in LMP1B95‐8 transgenic mice
Authors: QingLing Zhang , LiNa Yu , Li Liu , Shuang Wang , YuFang Yang , Yi Ding , Divakaran Jeevan , Xin Li , YanQing Ding
Published: November 2010

Latent membrane protein 1 (LMP1) of Epstein–Barr virus (EBV) can induce cell transformation and tumourigenesis, but the mechanism is not understood. Previous studies have suggested that LMP1 acts through up‐regulation of cellular proliferation pathways including the Wnt/β‐catenin pathway, in which β‐catenin is the central effector. Increased levels of β‐catenin coupled with a decrease in E‐cadherin lead to reduced cell adhesion. This pathway is antagonized by WTX (Wilms' tumour gene on the X chromosome), which can promote the ubiquitination and degradation of β‐catenin. In the present study, we established L2/LMP1B95 − 8/EGFP transgenic mice to investigate the in vivo role of LMP1. Down‐regulation of WTX and E‐cadherin was accompanied by increased expression of β‐catenin in these mice. Even though invasive tumours did not develop, dysplasia was seen in the nasopharynx and oropharynx epithelium of these transgenic mice. Analysis of LMP1+, WTX+, and LMP1 siRNA silenced HNE‐1 cell lines demonstrated that WTX could exert a dominant role in LMP1‐mediated WNT/β‐catenin pathway regulation. This study indicates that LMP1 antagonizes the WNT/β‐catenin pathway by inhibiting WTX, and this reduction in WTX is associated with epithelial dysplasia via regulation of the WNT/β‐catenin pathway molecules E‐cadherin and β‐catenin. Further studies are required for a better understanding of the relationship between LMP1‐mediated antagonization of the WNT/β‐catenin pathway and tumourigenesis. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The Saint Siluan warning signs of cancer in children: Impact of education in rural South Africa
Authors: Poyiadjis Stelios , Wainwright Linda , Naidu Gita , Mackinnon Diane , Poole Janet
Published: November 2010

Two thirds of children with cancer never reach a specialist centre for treatment in South Africa. The majority of those who present have advanced disease. A campaign was undertaken to educate the public and the primary health workers on the Saint Siluan early warning signs of cancer in children. There was a statistically significant increase in the number of new patients referred in the 6 years following the campaign (P = 0.001), but did not succeed in achieving the referral of patients at earlier stages of disease. This list of the warning signs appears to be useful in promoting awareness of cancer. Pediatr Blood Cancer 2011;56:314–316. © 2010 Wiley‐Liss, Inc.
Structural insights into a low‐spin myoglobin variant with bis‐histidine coordination from molecular modeling
Authors: Lin Ying‐Wu
Published: November 2010

Rational design of functional enzymes is a powerful strategy to gain deep insights into more complex native enzymes, such as nitric oxide reductase (NOR). Recently, we engineered a functional model of NOR by creating a two His and one Glu (2‐His‐1‐Glu) non‐heme iron center in sperm whale myoglobin (swMb L29E, F43H, H64, called FeBMb(‐His)). It was found that FeBMb(‐His) adopts a low‐spin state with bis‐His coordination in the absence of metal ions binding to the designed metal center. However, no structural information was available for the variant in this special spin state. We herein performed molecular modeling of FeBMb(‐His) and compared with the X‐ray structure of its copper bound derivative, Cu(II)‐CN−‐FeBMb(‐His), resolved recently at a high resolution (1.65 Å) (PDB entry 3MN0). The simulated structure shows that mutation of Leu to Glu at position 29 in the hydrophobic heme pocket alters the folding behavior of Mb. The hydrogen bond between Glu29 and His64 further plays a role in stabilizing the bis‐His (His64/His93) coordination structure. This study offers an excellent example of using molecular modeling to gain insights in rational design of both structural and functional proteins. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Characterization of ZnO crystals grown by the vertical Bridgman method
Authors: Eisermann Sebastian , Laufer Andreas , Graubner Swen , Pinnisch Melanie , Stehr Jan , Lautenschläger Stefan , Hofmann Detlev M. , Meyer Bruno K. , Klimm Detlev , Schulz Detlev
Published: November 2010

ZnO crystals grown by the vertical Bridgman technique were comprehensively characterized in view of the impurities and intrinsic defects in the material. It is shown that residual Al is the cause of the residual n‐type conductivity and intrinsic defects play only a minor role in the samples. Annealing the samples at 1100 °C for 1 h in oxygen atmosphere improves the surface properties of the samples without having negative effects on their optical and electrical properties.
Mechanism of excitation energy transfer between ring‐shaped aggregates of pigments
Authors: Nakatani Masatoshi , Tei Go , Ishihara Hajime
Published: November 2010

We theoretically study the mechanism of excitation energy transfer (EET) between two ring‐shaped aggregates of pigments. Dynamics of the pigment system and the light field are described by a Markovian quantum master equation and the Maxwell's equations, respectively. Self‐consistently solving these equations, we investigate the interplay between light and aggregates of pigments. From our calculation, it is revealed that the isotropic property gives two coupling constants, which prevents the deterioration of the EET rate between anisotropic dipoles. The distance dependence of the coupling strengths is also calculated for all excited states of the aggregate, which shows that each excited state has a different distance dependence of the coupling strength.
Upregulation of bradykinin receptors is implicated in the pain associated with caerulein‐induced acute pancreatitis
Authors: Takemura Yoshinori , Furuta Sadayoshi , Hirayama Shigeto , Miyashita Kazuhiko , Imai Satoshi , Narita Michiko , Kuzumaki Naoko , Tsukiyama Yoshi , Yamazaki Mitsuaki , Suzuki Tsutomu , Narita Minoru
Published: November 2010

Although the way for pain management associated with acute pancreatitis has been searched for, there are not enough medications available for it. The aim of the present study was to investigate the role of bradykinin (BK) in pain related to acute pancreatitis. After repeated injections of caerulein (50 μg/kg and 6 times), mice showed edema in the pancreas, and blood concentrations of pancreatic enzymes (amylase and lipase) were clearly elevated. A histopathological study demonstrated that caerulein caused tissue damage characterized by edema, acinar cell necrosis, interstitial hemorrhage, and inflammatory cell infiltrates. Furthermore, the mRNA levels of interleukin‐1β and monocyte chemotactic protein (MCP)‐1 were significantly increased in the pancreas of caerulein‐treated mice. The sensitivity of abdominal organs as measured by abdominal balloon distension was enhanced in caerulein‐injected mice, suggesting that caerulein caused pancreatic hyperalgesia. Moreover, repeated treatment with caerulein resulted in cutaneous tactile allodynia of the upper abdominal region as demonstrated by the use of von Frey filaments, indicating that caerulein‐treated mice exhibited referred pain. Under this condition, the mRNA levels of bradykinin B1 receptor (BKB1R) and bradykinin B2 receptor (BKB2R) were significantly increased in the dorsal root ganglion (DRG). Finally, we found that des‐Arg9‐(Leu8)‐bradykinin (BKB1R antagonist) and HOE‐140 (BKB2R antagonist) attenuated the acute pancreatitis pain‐like state in caerulein‐treated mice. These findings suggest that the upregulation of BK receptors in the DRG may, at least in part, contribute to the development of the acute pancreatitis pain‐like state in mice. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
Rapid Quantitative Analysis of Lipids Using a Colorimetric Method in a Microplate Format
Authors: Cheng Yu‐Shen , Zheng Yi , VanderGheynst Jean S.
Published: November 2010

A colorimetric sulfo‐phospho‐vanillin (SPV) method was developed for high throughput analysis of total lipids. The developed method uses a reaction mixture that is maintained in a 96‐well microplate throughout the entire assay. The new assay provides the following advantages over other methods of lipid measurement: (1) background absorbance can be easily corrected for each well, (2) there is less risk of handling and transferring sulfuric acid contained in reaction mixtures, (3) color develops more consistently providing more accurate measurement of absorbance, and (4) the assay can be used for quantitative measurement of lipids extracted from a wide variety of sources. Unlike other spectrophotometric approaches that use fluorescent dyes, the optimal spectra and reaction conditions for the developed assay do not vary with the sample source. The developed method was used to measure lipids in extracts from four strains of microalgae. No significant difference was found in lipid determination when lipid content was measured using the new method and compared to results obtained using a macro‐gravimetric method.
A (rough) pathwise approach to a class of non-linear stochastic partial differential equations
Authors: Oberhauser Harald , Caruana Michael , Friz Peter K.
Published: November 2010

We consider non-linear parabolic evolution equations of the form

\partial _{t}u = F(t,x,Du,D^{2}u)

, subject to noise of the form

H(x,Du) \circ dB

where
H
is linear in
Du
and

\circ \:dB

denotes the Stratonovich differential of a multi-dimensional Brownian motion. Motivated by the essentially pathwise results of [P.-L. Lions, P.E. Souganidis, Fully nonlinear stochastic partial differential equations, C. R. Acad. Sci. Paris Sér. I Math. 326 (9) (1998) 1085–1092] we propose the use of rough path analysis [T.J. Lyons, Differential equations driven by rough signals, Rev. Mat. Iberoamericana 14 (2) (1998) 215–310] in this context. Although the core arguments are entirely deterministic, a continuity theorem allows for various probabilistic applications (limit theorems, support, large deviations, …).
Evidence for a quiet revolution: seasonal variation in colonies of the specialist tansy aphid,Macrosiphoniella tanacetaria(Kaltenbach) (Hemiptera: Aphididae) studied using microsatellite markers
Authors: Loxdale H.D. , Massonnet B. , Schöfl G. , Weisser W.W.
Published: November 2010

In cyclical parthenogens, clonal diversity is expected to decrease due to selection and drift during the asexual phase per number of asexual generations. The decrease in diversity may be counteracted by immigration of new genotypes. We analysed temporal variation in clonal diversity in colonies of the monophagous tansy aphid,Macrosiphoniella tanacetaria(Kaltenbach), sampled four times over the course of a growing season. In a related field study, we recorded aphid colony sizes and the occurrence of winged dispersers throughout the season. The number of colonies increased from April, when asexual stem mothers hatched from the sexually produced eggs, to the end of June. The proportion of colonies with winged individuals also increased over this period. After a severe reduction in colony sizes in late summer, a second expansion phase occurred in October when sexuals were produced. At the season's end, the only winged forms were males. A linked genetic study showed that the number of microsatellite multilocus genotypes and genetic variability assessed at three polymorphic loci per colony decreased from June to October. Overall, the relatedness of wingless to winged individuals within colonies was lower than average relatedness among wingless individuals, suggesting that winged forms mainly originated in different colonies. The results demonstrate that patterns of genetic diversity within colonies can be explained by the antagonistic forces of clonal selection, migration and genetic drift (largely due to midsummer population bottlenecks). We further suggest that the males emigrate over comparatively longer distances than winged asexual females.
Response to Prasenjit Duara, “Asia Redux”
Authors: Andaya Barbara Watson
Published: November 2010

In his provocative essay, Prasenjit Duara argues that prior to the nineteenth century, the web of maritime trade networks infused the ill-defined area we call “Asia” with a genuine coherence, providing a conduit for cultural flows that readily permitted interactive relationships and the mutual adoption of new beliefs and practices. By the late nineteenth century, however, the imperial powers sought to ensure their global dominance by creating regional blocs consisting of territories that were economically subservient to the metropole. The consequent focus on the establishment of territorial boundaries encouraged a “nationalist congruence between state and culture” that gathered pace over the next hundred years. Only now are we beginning to see an Asia where interdependence and increasing cultural contact, carrying echoes of past connectivities, have opened up new opportunities by which a “transnational consciousness” can and should be encouraged.
The Term Structure of Bond Market Liquidity and Its Implications for Expected Bond Returns
Authors: Goyenko Ruslan , Subrahmanyam Avanidhar , Ukhov Andrey
Published: November 2010

Previous studies of Treasury market illiquidity span short time periods and focus on particular maturities. In contrast, we study the time series of illiquidity for different maturities over an extended period of time. We also compare time-series determinants of on-the-run and off-the-run illiquidity. Illiquidity increases and the difference between spreads of long- and short-term bonds significantly widens during recessions, suggesting a “flight to liquidity,” wherein investors shift into the more liquid short-term bonds during economic contractions. Macroeconomic variables such as inflation and federal funds rates forecast off-the-run illiquidity significantly but have only modest forecasting ability for on-the-run illiquidity. Bond returns across maturities are forecastable by off-the-run but not on-the-run bond illiquidity. Thus, off-the-run illiquidity, by reflecting macro shocks first, is the primary source of the liquidity premium in the Treasury market.
Ligulaintestinalis infection is associated with alterations of both brain and gonad aromatase expression in roach (Rutilusrutilus)
Authors: Boulange-Lecomte C. , Geraudie P. , Forget-Leray J. , Gerbron M. , Minier C.
Published: November 2010

The tapeworm Ligulaintestinalis commonly infests roach (Rutilusrutilus) and is responsible for the inhibition of gonad development. In order to better understand the effect of the plerocercoid on fish physiology, and to discriminate parasitization effects from those of endocrine-disrupting compounds (EDC), Cyp19b and Cyp19a aromatase expression was investigated by real-time quantitative polymerase chain reaction (PCR) in brain and gonads of ligulosed roach, caught from a reference site. Data were compared to reproductive and endocrine endpoints previously reported in a larger cohort study (including the sampled population of the present one), such as gonadosomatic index, Fulton index, gonadal histology, plasma sex steroid levels and brain aromatase activity. A decrease in Cyp19b expression in the brain of infected fish was demonstrated, in agreement with the reduction of aromatase activity previously described. In contrast, Cyp19a expression in the gonads appeared to be enhanced in ligulosed fish, in accordance with the presence of immature but differentiated sexual tissues. Together these results show that: (1) L. intestinalis infestation results in an alteration of aromatase expression which, in particular, may have profound effects on the fish brain; and (2) L. intestinalis infection must be considered as a major confounding factor in ecotoxicological studies using aromatase expression as an EDC biomarker. Moreover, the concordance between activity and expression – investigated for the first time in the same population – gives a functional relevance to the transcript aromatase dosage in the brain. Finally, quantitative PCR was confirmed as a sensitive approach, enabling aromatase status to be defined in the poorly developed gonads of ligulosed individuals.
A decade of high‐latitude lightning location: Effects of the evolving location network in Finland
Authors: Mäkelä Antti , Tuomi Tapio J. , Haapalainen Jussi
Published: November 2010

The present lightning location system of the Finnish Meteorological Institute has been in operation since 1998. We present statistics from the 10‐year period 1998–2007. The main emphasis of this study is to give a comprehensive analysis of the development of the location system. Our results complement previous studies by providing 10‐year lightning statistics from high latitudes in Europe (60–70°N). The changes in the detection efficiency have also been discussed. Our results indicate that in Finland (1) the median (average) peak currents in 2007 were −11.3 (−16.0) kA and +13.3 (+20.7) kA for negative and positive flashes, (2) the percentage of positive flashes in 2007 was 17%, (3) the average multiplicity for negative (positive) flashes in 2007 was 2.1 (1.2), (4) the median semimajor axis of the 50% location error ellipse in 2007 was 600 m (for 92% of flashes it was below 5 km), and (5) the average number of sensors reporting a flash in 2007 was 6.3. The network has experienced several configuration changes, leading to a more stable and better performing system, but these technical changes have also caused significant changes in the statistics of the measured lightning data. Clearly, lightning statistics over a 10‐year period cannot be handled without considering the impact of technical changes on the detection network.
GRACE Hydrological estimates for small basins: Evaluating processing approaches on the High Plains Aquifer, USA
Authors: Longuevergne Laurent , Scanlon Bridget R. , Wilson Clark R.
Published: November 2010

The Gravity Recovery and Climate Experiment (GRACE) satellites provide observations of water storage variation at regional scales. However, when focusing on a region of interest, limited spatial resolution and noise contamination can cause estimation bias and spatial leakage, problems that are exacerbated as the region of interest approaches the GRACE resolution limit of a few hundred km. Reliable estimates of water storage variations in small basins require compromises between competing needs for noise suppression and spatial resolution. The objective of this study was to quantitatively investigate processing methods and their impacts on bias, leakage, GRACE noise reduction, and estimated total error, allowing solution of the trade‐offs. Among the methods tested is a recently developed concentration algorithm called spatiospectral localization, which optimizes the basin shape description, taking into account limited spatial resolution. This method is particularly suited to retrieval of basin‐scale water storage variations and is effective for small basins. To increase confidence in derived methods, water storage variations were calculated for both CSR (Center for Space Research) and GRGS (Groupe de Recherche de Géodésie Spatiale) GRACE products, which employ different processing strategies. The processing techniques were tested on the intensively monitored High Plains Aquifer (450,000 km2 area), where application of the appropriate optimal processing method allowed retrieval of water storage variations over a portion of the aquifer as small as ∼200,000 km2.
Impact of Hurricane Katrina (2005) on shelf organic carbon burial and deltaic evolution
Authors: Allison Mead A. , Dellapenna Timothy M. , Gordon Elizabeth S. , Mitra Siddhartha , Petsch Steven T.
Published: November 2010

Sediment cores from the continental shelf adjacent to the Mississippi River delta immediately after the passage of Hurricane Katrina were used to examine the magnitude, and implications for the carbon budget, of sediment and particulate organic carbon (POC) remobilized by the storm on the river‐dominated continental shelf. POC was sourced from incision of the innermost continental shelf (<25 m water depth) and from surge ebb advection from adjacent wetlands and shallow estuaries, and was re‐deposited in deeper water on the shelf. This pulse of young (<1,600 yBP) labile POC, mixed with relict (>5000 yBP) POC eroded from the seafloor, has major implications for the remineralization versus burial of POC in deltas. The scale of erosional deflation of the shelf in water depths beyond seasonal wave‐current conditions suggests that, over millennia, tropical cyclones may be responsible for partly removing prodeltaic strata from the geologic record in low‐to‐mid latitude deltas.
Interannual variations of tropical upper tropospheric humidity and tropical rainy‐region SST: Comparisons between models, reanalyses, and observations
Authors: Chuang Huiwen , Huang Xianglei , Minschwaner Kenneth
Published: November 2010

Tropical deep convection plays a key role in the vertical transport of moisture to the upper troposphere. Here we investigate relations between the interannual anomalies of the sea surface temperature (SST) in the tropical strong precipitation regions (rainy‐region SST) and tropical upper tropospheric humidity (UTH), as seen from the ECMWF ERA‐40 and ERA‐interim reanalyses, AIRS observations, and four global climate model (GCM) simulations from the IPCC AR4 archive. Important differences are found between the two reanalyses and between models and observations/reanalyses. The mean correlation coefficients between interannual anomalies of UTH (250–400 mb) and rainy‐region SST are 0.46 for the ECMWF ERA‐40 but 0.86 for ERA‐interim and 0.87 for the 6‐year AIRS data, which are all higher than their counterparts when the tropical‐mean SST anomalies are used instead. All GCMs exhibit systematically stronger correlations (∼0.95) for both types of SST anomalies. Fractional changes of UTH anomalies with respect to the two types of SST anomalies are also examined. Using modeled and reanalyses tropical temperature profiles as input, an idealizing model that assumes deep convection for the only source of water vapor is used to compute the UTH variations. Except for the case of ECMWF ERA‐40, the idealized model reasonably reproduces the UTH profiles at 250 and 300 mb for all other cases, corroborating the dominate control of deep convection on the humidity in these layers. The UTH at 200 mb derived from the idealized model is 1.5 to 2 times more humid than those from the GCMs and reanalyses, suggesting the importance of drying mechanisms at this level and probably above. Possible causes for the outlier behavior of ERA‐40 are also discussed.
Ecohydrological responses of dense canopies to environmental variability: 1. Interplay between vertical structure and photosynthetic pathway
Authors: Drewry D. T. , Kumar P. , Long S. , Bernacchi C. , Liang X.‐Z. , Sivapalan M.
Published: November 2010

Vegetation acclimation to changing climate, in particular elevated atmospheric concentrations of carbon dioxide (CO2), has been observed to include modifications to the biochemical and ecophysiological functioning of leaves and the structural components of the canopy. These responses have the potential to significantly modify plant carbon uptake and surface energy partitioning, and have been attributed with large‐scale changes in surface hydrology over recent decades. While the aggregated effects of vegetation acclimation can be pronounced, they often result from subtle changes in canopy properties that require the resolution of physical, biochemical and ecophysiological processes through the canopy for accurate estimation. In this paper, the first of two, a multilayer canopy‐soil‐root system model developed to capture the emergent vegetation responses to environmental change is presented. The model incorporates both C3 and C4 photosynthetic pathways, and resolves the vertical radiation, thermal, and environmental regimes within the canopy. The tight coupling between leaf ecophysiological functioning and energy balance determines vegetation responses to climate states and perturbations, which are modulated by soil moisture states through the depth of the root system. The model is validated for three growing seasons each for soybean (C3) and maize (C4) using eddy‐covariance fluxes of CO2, latent, and sensible heat collected at the Bondville (Illinois) Ameriflux tower site. The data set provides an opportunity to examine the role of important environmental drivers and model skill in capturing variability in canopy‐atmosphere exchange. Vertical variation in radiative states and scalar fluxes over a mean diurnal cycle are examined to understand the role of canopy structure on the patterns of absorbed radiation and scalar flux magnitudes and the consequent differences in sunlit and shaded source/sink locations through the canopies. An analysis is made of the impact of soil moisture stress on carbon uptake and energy flux partitioning at the canopy‐scale and resolved through the canopy, providing insight into the roles of canopy structure and metabolic pathway on the response of each crop to moisture deficits. Model calculations indicate increases in water use efficiency (WUE) with increasing moisture stress, with average maize WUE increases of 45% at the highest levels of plant stress examined here, relative to 20% increases for soybean.
Dynamics of shallow lateral shear layers: Experimental study in a river with a sandy bed
Authors: Sukhodolov Alexander N. , Schnauder Ingo , Uijttewaal Wim S. J.
Published: November 2010

Shallow lateral shear layers forming between flows with different velocities, though essential for mixing processes in natural streams, have been examined only in laboratory settings using smooth, fixed‐bed channels. This paper reports the results of an experimental study of a shear layer in a straight reach of a natural river where the layer, in contrast to the two‐dimensional structure observed in the laboratory, is highly three‐dimensional. The study included pronounced transverse pressure gradients, which influenced shear layer structure compared to flume experiments. It also introduces an analysis that complements conventional theory on mixing layers. The lateral velocity gradient between the flows downstream from a splitter plate placed in the river, the principal controlling factor, was adjusted for three experimental runs to determine the influence of different gradients on shear‐layer dynamics. In each run, detailed three‐dimensional measurements of mean and turbulent characteristics were obtained at five cross sections downstream from the splitter plate. Although experimental results agreed with conventional mixing‐layer theories with respect to turbulence, the dynamics of the shear layers were dominated by the mean lateral fluxes of momentum. After re‐examining the governing equations, we developed a parabolic equation describing the shear layer evolution and several scaling relations for essential terms of the energy budget: mean and turbulent lateral fluxes of momentum, turbulent kinetic energy, and dissipation rates. The study also provides insight into the spectral dynamics of turbulence in the shear layer and clarifies previous observations reported for confluences in natural streams.
Macrophage Migration Inhibitory Factor Promotes Cell Death and Aggravates Neurologic Deficits after Experimental Stroke
Authors: Inácio Ana R , Ruscher Karsten , Leng Lin , Bucala Richard , Deierborg Tomas
Published: November 2010

Multiple mechanisms contribute to tissue demise and functional recovery after stroke. We studied the involvement of macrophage migration inhibitory factor (MIF) in cell death and development of neurologic deficits after experimental stroke. Macrophage migration inhibitory factor is upregulated in the brain after cerebral ischemia, and disruption of the Mif gene in mice leads to a smaller infarct volume and better sensory-motor function after transient middle cerebral artery occlusion (tMCAo). In mice subjected to tMCAo, we found that MIF accumulates in neurons of the peri-infarct region, particularly in cortical parvalbumin-positive interneurons. Likewise, in cultured cortical neurons exposed to oxygen and glucose deprivation, MIF levels increase, and inhibition of MIF by (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) protects against cell death. Deletion of MIF in Mif−/− mice does not affect interleukin-1 β protein levels in the brain and serum after tMCAo. Furthermore, disruption of the Mif gene in mice does not affect CD68, but it is associated with higher galectin-3 immunoreactivity in the brain after tMCAo, suggesting that MIF affects the molecular/cellular composition of the macrophages/microglia response after experimental stroke. We conclude that MIF promotes neuronal death and aggravates neurologic deficits after experimental stroke, which implicates MIF in the pathogenesis of neuronal injury after stroke.
Spatial Variability in Soil Microbial Communities in a Nitrogen-Saturated Hardwood Forest Watershed
Authors: Gilliam Frank
Published: November 2010

The long-term reference watershed (WS4), at Fernow Experimental Forest, West Virginia, displays symptoms of N saturation despite considerable spatial heterogeneity in soil properties, such as texture, N pools, and cycling rates. We identified a weathering gradient of three sites within WS4 by assessing differences in clay content across a common geologic substrate. Across these sites (LN, MN, and HN), NO3 production rates vary significantly (low, medium, and high nitrification, respectively) and are negatively related to clay content. It is unknown whether microbial communities vary across these sites and contribute to variability in NO3 production. This study characterized soil microbial communities along this gradient and assessed factors potentially important in explaining microbial composition. We sampled mineral soil from each of the sites, analyzing for moisture, pH, organic matter, extractable N, and microbial biomass and community composition via phospholipid fatty acid (PLFA) analysis. Analysis of variance and canonical correspondence analysis indicated that microbial community composition varied among sites, with a predominance of fungal markers (18:2n6 and 18:1n9c) at the most weathered LN site and Gram negative bacteria (18:1n7c) at the less weathered MN and HN sites. Accordingly, the fungi/bacteria ratio increased in the direction of LN plots in ordination space. Correlations between measured environmental parameters and PLFA data suggest that acidic conditions and low NO3 abundance at the LN site have selected for fungal dominance, although other important factors known to exert an influence on soil microbial communities, such as differences in plant community and clay and organic matter content, may also be playing a role in determining the observed patterns.
Seasonal priority effects: Implications for invasion and restoration in California coastal sage scrub
Authors: Wainwright Claire , Cleland Elsa
Published: November 2010

Competition from exotic annual grasses (EAGs) threatens native plant communities in California. Coastal sage scrub communities have substantially diminished in area over the last century, in some instances by greater than 90%, while EAGs continue to proliferate. Several mechanisms may explain the success of EAGs, including the suppression of native seedlings by accumulated litter, exhaustion of soil moisture, and low seed production or dispersal of natives.The timing and magnitude of rainfall plays a significant role in determining the survival and reproduction of plant species in Mediterranean ecosystems. Populations of annuals fluctuate greatly from year to year, corresponding with variability in autumn precipitation. EAGs in California germinate quickly following small threshold rain events, whereas native species have more complex germination cues, such that exotic annual grasses become active earlier in the growing season. In this way, EAGs may exhibit a priority effect over native plant species with respect to establishment; however, they may have reduced success if their germination is induced at a time followed by a substantial drought (for instance, in the summer) so that they will not persist.The goal of this investigation is 1) to evaluate whether seasonal priority effects contribute to community-level patterns of abundance, and 2) whether late summer watering could be a feasible restoration technique for suppression of exotic annual grasses and weeds in Mediterranean ecosystems.
Phase synchronization between collective rhythms of globally coupled oscillator groups: Noiseless nonidentical case
Authors: Kawamura Yoji , Nakao Hiroya , Arai Kensuke , Kori Hiroshi , Kuramoto Yoshiki
Published: November 2010

We theoretically study the synchronization between collective oscillations exhibited by two weakly interacting groups of nonidentical phase oscillators with internal and external global sinusoidal couplings of the groups. Coupled amplitude equations describing the collective oscillations of the oscillator groups are obtained by using the Ott–Antonsen ansatz, and then coupled phase equations for the collective oscillations are derived by phase reduction of the amplitude equations. The collective phase coupling function, which determines the dynamics of macroscopic phase differences between the groups, is calculated analytically. We demonstrate that the groups can exhibit effective antiphase collective synchronization even if the microscopic external coupling between individual oscillator pairs belonging to different groups is in-phase, and similarly effective in-phase collective synchronization in spite of microscopic antiphase external coupling between the groups.
Role of single walled carbon nanotubes in improving the efficiency of poly-(3-hexylthiophene) based organic solar cells
Authors: Mallajosyula Arun Tej , Iyer S. Sundar Kumar , Mazhari Baquer
Published: November 2010

Poly-(3-hexylthiophene) (P3HT)—single walled carbon nanotube (SWNT) solar cells were fabricated and compared with single layer P3HT devices. P3HT:SWNT devices were found to have higher efficiencies than P3HT only devices by at least a factor of two. Zero field mobility values of 1.20×10−7 cm2 V−1 s−1 and 5.97×10−7 cm2 V−1 s−1 were calculated from space charge regime for P3HT and P3HT:SWNT, respectively. The SWNTs were predominantly of metallic nature, as revealed by Raman spectroscopy. Morphology studies show that the SWNTs increase local ordering of P3HT nanocrystals which can improve hole transport. They also show that the cathode-organic surface roughness and volume increase in the presence of SWNTs which can have significant positive effect on charge generation and collection at this interface. Variation in short circuit current with incident light intensity shows higher superlinear slope with SWNTs which also indicates that SWNTs aid in charge extraction from the device.
Impact of degree heterogeneity on the behavior of trapping in Koch networks
Authors: Zhang Zhongzhi , Gao Shuyang , Xie Wenlei
Published: November 2010

Previous work shows that the mean first-passage time (MFPT) for random walks to a given hub node (node with maximum degree) in uncorrelated random scale-free networks is closely related to the exponent γ of power-law degree distribution P(k)∼k−γ, which describes the extent of heterogeneity of scale-free network structure. However, extensive empirical research indicates that real networked systems also display ubiquitous degree correlations. In this paper, we address the trapping issue on the Koch networks, which is a special random walk with one trap fixed at a hub node. The Koch networks are power-law with the characteristic exponent γ in the range between 2 and 3, they are either assortative or disassortative. We calculate exactly the MFPT that is the average of first-passage time from all other nodes to the trap. The obtained explicit solution shows that in large networks the MFPT varies lineally with node number N, which is obviously independent of γ and is sharp contrast to the scaling behavior of MFPT observed for uncorrelated random scale-free networks, where γ influences qualitatively the MFPT of trapping problem.
Comment on “The effects of Bohm potential on ion-acoustic solitary waves interaction in a nonplanar quantum plasma” [Phys. Plasmas 17, 082307 (2010)]
Authors: Akbari-Moghanjoughi M.
Published: November 2010

Recently, Li [Phys. Plasmas 17, 082307 (2010)] has studied the effects of Bohm potential on interaction of nonplanar ion-acoustic solitary waves in an unmagnetized electron-positron-ion quantum plasma. In his work the extended reductive perturbation technique has been employed to reduce the basic quantum hydrodynamics plasma equations to Korteweg–de Vries evolution equations (one for each wave) as well as other coupled differential equations describing the phase variation of the resulting solitary waves. The calculated collisional phase-shifts are then numerically evaluated in terms of plasma parameters such as the fractional positron to ion number-density p, relative electron to positron Fermi-temperature σ and the quantum diffraction parameter H. We show that in the chosen plasma model, the parameters p and σ are not independent quantum plasma parameters which has important consequences on the graphical interpretations presented in the mentioned article.
Spherical polymer brushes under good solvent conditions: Molecular dynamics results compared to density functional theory
Authors: Lo Verso Federica , Egorov Sergei A. , Milchev Andrey , Binder Kurt
Published: November 2010

A coarse grained model for flexible polymers end-grafted to repulsive spherical nanoparticles is studied for various chain lengths and grafting densities under good solvent conditions by molecular dynamics methods and density functional theory. With increasing chain length, the monomer density profile exhibits a crossover to the star polymer limit. The distribution of polymer ends and the linear dimensions of individual polymer chains are obtained, while the inhomogeneous stretching of the chains is characterized by the local persistence lengths. The results on the structure factor of both single chain and full spherical brush as well as the range of applicability of the different theoretical tools are presented. Finally, a brief discussion of the experiment is given.
Two-tracer spectroscopy diagnostics of temperature profile in the conduction layer of a laser-ablated plastic foil
Authors: Zhang Jiyan , Yang Guohong , Hu Xin , Yang Jiamin , Ding Yaonan , Ding Yongkun , Zhang Baohan , Zheng Zhijian , Xu Yan , Yan Jun , Pei Wenbin
Published: November 2010

A technique that combines the diagnostics of electron temperature history and the measurements of ablation velocity with two-tracer x-ray spectroscopy has been developed for diagnosing the temperature profiles in the thermal conduction layers of laser-ablated plastic foils. The electron temperature in the plastic ablator was diagnosed using the isoelectronic line ratios of Al Lyα line to Mg Lyα line, emitted from a tracer layer of Al/Mg mixture buried under the ablator. The ablation velocity was inferred from the time delay between the onset time of x-ray line emissions from Al and Mg tracer layers buried at two depths in the ablator, respectively. From the measured electron temperatures and ablation velocity, the electron temperature profile in the conduction layer was inferred. The measured temperature profile was compared with the simulated one and reasonable agreement was found.
Energetic study of the transition to nonlinear state in two-dimensional electron temperature gradient fluid turbulence
Authors: Kim J.-H. , Terry P. W.
Published: November 2010

Eigenmode projection has been used in analysis of the two-dimensional numerical solution of electron temperature gradient (ETG) turbulence. The secondary Kelvin–Helmholtz instability (KHI) that breaks up the primary ETG structure at the onset of saturation is found to be associated with strong excitation of damped eigenmodes and strong energy damping. While the KHI structure induces some fine scale motions, which can be dissipated by collisional damping, the structure also damps directly at low poloidal wavenumbers through stable eigenmodes. The latter process is persistent in time, while the former occurs only transiently at the initial breakdown of the linearly dominant ETG structure. The persistence of energy damping by stable eigenmodes during and after the transition is enabled by nonlinear advection of electron pressure. Thus, KHI in this system couples with electron pressure advection to generate a dissipative structure at low poloidal wavenumber.
Gyrokinetic particle simulation of beta-induced Alfvén eigenmode
Authors: Zhang H. S. , Lin Z. , Holod I. , Wang X. , Xiao Y. , Zhang W. L.
Published: November 2010

The beta-induced Alfvén eigenmode (BAE) in toroidal plasmas is studied using global gyrokinetic particle simulations. The BAE real frequency and damping rate measured in the initial perturbation simulation and in the antenna excitation simulation agree well with each other. The real frequency is slightly higher than the ideal magnetohydrodynamic (MHD) accumulation point frequency due to the kinetic effects of thermal ions. Simulations with energetic particle density gradient show exponential growth of BAE with a growth rate sensitive to the energetic particle temperature and density. The nonperturbative contributions by energetic particles modify the mode structure and reduce the frequency relative to the MHD theory. The finite Larmor radius effects of energetic particles reduce the BAE growth rate. Benchmarks between gyrokinetic particle simulation and hybrid MHD-gyrokinetic simulation show good agreement in BAE real frequency and mode structure.