bluuebunny/crossref_metadata_2025_split huggingface dataset:
A review on experimental studies of biosorption of heavy metals by Aspergillus niger
Authors: Mukhopadhyay Mausumi , Noronha S. B. , Suraishkumar G. K. 
Published: March 2011

AbstractRecent developments in the field of environmental biotechnology lead to the search for adsorbents of biological origin, which is reasonably cheap for toxic trace metal removal. This method is specifically termed as biosorption. In this paper, biosorption of heavy metals by Aspergillus niger is reviewed. Characterisation of A. niger in heavy metal biosorption is extensively discussed. Batch and continuous processes are discussed in details. Influence of process parameters like biomass dosage rate, initial metal ion concentration, and pH of the solution, pretreatment, impact of co‐cations on metal biosorption is also discussed. Modelling for batch and continuous process operations are focused extensively. Mechanism of biosorption by A. niger is elaborated.
Molecular analysis of neurogenic placode development in a basal ray‐finned fish
Authors: Modrell Melinda S. , Buckley David , Baker Clare V.H. 
Published: March 2011

AbstractNeurogenic placodes are transient, thickened patches of embryonic vertebrate head ectoderm that give rise to the paired peripheral sense organs and most neurons in cranial sensory ganglia. We present the first analysis of gene expression during neurogenic placode development in a basal actinopterygian (ray‐finned fish), the North American paddlefish (Polyodon spathula). Pax3 expression in the profundal placode confirms its homology with the ophthalmic trigeminal placode of amniotes. We report the conservation of expression of Pax2 and Pax8 in the otic and/or epibranchial placodes, Phox2b in epibranchial placode‐derived neurons, Sox3 during epibranchial and lateral line placode development, and NeuroD in developing cranial sensory ganglia. We identify Sox3 as a novel marker for developing fields of electrosensory ampullary organs and for ampullary organs themselves. Sox3 is also the first molecular marker for actinopterygian ampullary organs. This is consistent with, though does not prove, a lateral line placode origin for actinopterygian ampullary organs. genesis 49:278–294, 2011. © 2011 Wiley‐Liss, Inc.
Mechanisms that underlie co‐variation of the brain and face
Authors: Marcucio Ralph S. , Young Nathan M. , Hu Diane , Hallgrimsson Benedikt 
Published: March 2011

AbstractThe effect of the brain on the morphology of the face has long been recognized in both evolutionary biology and clinical medicine. In this work, we describe factors that are active between the development of the brain and face and how these might impact craniofacial variation. First, there is the physical influence of the brain, which contributes to overall growth and morphology of the face through direct structural interactions. Second, there is the molecular influence of the brain, which signals to facial tissues to establish signaling centers that regulate patterned growth. Importantly, subtle alterations to these physical or molecular interactions may contribute to both normal and abnormal variation. These interactions are therefore critical to our understanding of how a diversity of facial morphologies can be generated both within species and across evolutionary time. genesis 49:177–189, 2011. © 2011 Wiley‐Liss, Inc.
Odd‐skipped maintains prohemocyte potency and blocks blood cell development in Drosophila
Authors: Gao Hongjuan , Wu Xiaorong , Fossett Nancy 
Published: March 2011

AbstractStudies using Drosophila have contributed significantly to our understanding of regulatory mechanisms that control stem cell fate choice. The Drosophila blood cell progenitor or prohemocyte shares important characteristics with mammalian hematopoietic stem cells, including quiescence, niche dependence, and the capacity to form all three fly blood cell types. This report extends our understanding of prohemocyte fate choice by showing that the zinc‐finger protein Odd‐skipped promotes multipotency and blocks differentiation. Odd‐skipped was expressed in prohemocytes and downregulated in terminally differentiated plasmatocytes. Furthermore, Odd‐skipped maintained the prohemocyte population and blocked differentiation of plasmatocytes and lamellocytes but not crystal cells. A previous study showed that Odd‐skipped expression is downregulated by Decapentaplegic signaling. This report provides a functional basis for this regulator/target pair by suggesting that Decapentaplegic signaling limits Odd‐skipped expression to promote prohemocyte differentiation. Overall, these studies are the basis for a gene regulatory model of prohemocyte cell fate choice. genesis, 49:105–116, 2011. © 2011 Wiley‐Liss, Inc.
Vertical mixing of gravel over a long flood series
Authors: Haschenburger Judith K. 
Published: March 2011

ABSTRACTVertical sediment exchange is a fundamental component of bedload transport in gravel‐bed channels. This paper describes the characteristic depth of exchange achieved over a long flood series. Analysis is based on 11 recoveries of magnetically tagged gravels deployed in Carnation Creek, Canada, completed between 1990 and 2008. Vertical grain exchange mixes gravels throughout the streambed relatively rapidly. Within one to eight floods the mean burial depth approaches two times the surface layer thickness, quantified by the 90th percentile of the size distribution. Finer gravels are mixed more rapidly into the bed than coarser gravels. Both active and passive grain exchanges throughout most of the bed produce the overall vertical distribution of marked grains. Gravel exchanges exhibit fairly consistent patterns once tracers are well mixed by large floods. Results highlight the role of flood sequence in determining exchange depths, support the notion of an upper limit to exchange, and underscore the importance of passive grain exchange. Copyright © 2011 John Wiley & Sons, Ltd.
A call for standardization of aeolian process measurements: moving beyond relative case studies
Authors: Barchyn Thomas E. , Hugenholtz Chris H. , Ellis Jean T. 
Published: March 2011

ABSTRACTProgress in some areas of process‐based aeolian sediment transport research is hampered by limited opportunities for data comparison, synthesis, and integration. This is partially due to a lack of reliable comparison methods. Many comparison methods are forms of calibration that are either restrictive (e.g., time‐averages only) or non‐existent (e.g., for field‐based sediment transport thresholds or vertical mass flux profiles). It is believed that the adoption of standard methods for common measurements may improve inter‐study comparison, add value and longevity to data, and advance integrative modeling efforts. Examples of approaches in allied disciplines where standards are used routinely are reviewed and we discuss how the mutual benefits of standardized data could outweigh perceived disadvantages. Overall, the goal of this commentary is to encourage discussion, self‐assessment, and forethought with regard to measurement methods used in process‐based aeolian geomorphology. Copyright © 2011 John Wiley & Sons, Ltd.
Using Firm‐Level Leverage as an Investment Strategy
Authors: Muradoğlu Yaz Gűlnur , Sivaprasad Sheeja 
Published: March 2011

ABSTRACTWe use an investment strategy based on firm‐level capital structures. Investing in low‐leverage firms yields abnormal returns of 4.43% per annum. If an investor holds a portfolio of low‐leverage and low‐market‐to‐book‐ratio firms, abnormal returns increase to 16.18% per annum. A portfolio of low leverage and low market risk yields abnormal returns of 6.67% and a portfolio of small firms with low leverage earns 5.37% per annum. We use the Fama‐Macbeth (1973) methodology with modifications. We confirm that portfolios based on low leverage earn higher returns in longer investment horizons. Our results are robust to other risk factors and the risk class of the firm. Copyright © 2011 John Wiley & Sons, Ltd.
Dynamic monitoring of cytosolic glucose in single astrocytes
Authors: Prebil Mateja , Vardjan Nina , Jensen Jørgen , Zorec Robert , Kreft Marko 
Published: March 2011

AbstractIt is becoming increasingly clear that astrocytes are no longer playing a subservient role to neurons in the central nervous system (CNS), and that these cells are being considered as active communication integrators. They respond to neurotransmitters by the regulated release of gliotransmitters. The delay between neurotransmitter activation and the release of gliotransmitters from astrocytes is in the time‐domain of subseconds, much slower than the submillisecond synaptic delay. Astrocytes also control microcirculation and provide metabolic support for neurons. However, the dynamics of their energy metabolic response to neurotransmitter application is not known. We here used a FRET glucose nanosensor to dynamically measure the cytosolic glucose concentration in single astrocytes. We show that following the adrenaline or noradrenaline stimulation the availability of cytosolic glucose is increased promptly after stimulation with a time‐constant of 116.7 s and 115.9 s, respectively. A decline in cytosolic glucose concentration with a time‐constant of 50.7 s was observed during glutamate and 16.7 s during lactate addition to astrocytes, when these were bathed in the presence of extracellular glucose‐containing solution, likely reflecting predominant glucose engagement in glycogen synthesis. In contrast, in the glucose‐free extracellular solution, glutamate application to astrocytes resulted in a slow increase in cytosolic glucose concentration, consistent with the view that glutamate may be an alternative energy source in hypoglycemic conditions. We conclude that astrocytic cytosolic glucose metabolism responds in the time‐domain of tens of seconds, which is slower compared to the whole brain functional magnetic resonance imaging measurements of the local intravascular hemodynamic response. © 2011 Wiley‐Liss, Inc.
Percutaneous absorption of haloacetonitriles and chloral hydrate and simulated human exposures
Authors: Trabaris Maria , Laskin Jeffrey D. , Weisel Clifford P. 
Published: March 2011

ABSTRACTDisinfection‐by‐products (DBPs) have long been a human health concern and many are known carcinogens and teratogens. Skin is exposed to DBPs in water through bathing and swimming; however, dermal uptake of many DBPs has not been characterized. The present studies were initiated to measure the permeation coefficients (Kp) for haloacetonitriles (HANs) and chloral hydrate (CH), important cytotoxic DBPs. The Kp values measured using fully hydrated dermatomed torso skin at 37 °C for the HANs ranged from 0.099 to 0.17 cm h−1, and was 0.0039 cm h−1 for CH. Of the HANs, dibromoacetonitrile had the highest permeability while chloroacetonitrile had the lowest permeability and a direct relationship was observed between their Kp and their octanol/water partition coefficients (Kow). The Kp values of the HANs were also approximately 30 times that of CH. The monthly dermal and ingestion doses of HANs and CH of an average American population were estimated using Monte Carlo simulations. The dermal doses of HANs from showering and bathing ranged from 0.39 to 0.78 times their ingestion doses but only approximately 0.02 times their ingestion doses for CH, assuming that the Kp values determined are applicable to shorter water contact times. However, that ratio can vary markedly with chlorinated swimming pool exposures, with a range of 0.30–2.3 for HANs and 0.19–0.25 for CH. Dermal exposure to HANs and CH seems to be a significant route of exposure and should be considered when evaluating their total exposure during the routine usage of water for bathing and swimming. Copyright © 2011 John Wiley & Sons, Ltd.
Stoichiometric and kinetic evaluation of simultaneous nitrification and denitrification in a membrane bioreactor at steady state
Authors: Sarioglu Murat , Insel Guclu , Artan Nazik , Orhon Derin 
Published: March 2011

AbstractBACKGROUND: This study concerned the stoichiometric evaluation of simultaneous nitrification and denitrification in a membrane bioreactor. The evaluation was made to derive relevant mass balance equations for all parameters affecting nitrogen removal and to set the basis for a rational design procedure.RESULTS: The basic stoichiometry was defined to include the effect of oxygen diffusion through microbial flocs by means of half saturation constants in corresponding switching functions. The stoichiometric relationships were used as tools for the design procedure targeting the desired level of nitrogen removal.CONCLUSION: A comparison was made with the outputs associated with a conventional activated sludge system for major design parameters such as denitrification potential, active heterotrophic and autotrophic biomass, oxygen requirements, etc. The proposed rational design for nitrogen removal was tested and validated using model simulation for steady state MBR operation under selected conditions. Copyright © 2011 Society of Chemical Industry
Convex excess in partial cubes
Authors: Klavžar Sandi , Shpectorov Sergey 
Published: March 2011

AbstractThe convex excess ce(G) of a graph G is introduced as where the summation goes over all convex cycles of G. It is proved that for a partial cube G with n vertices, m edges, and isometric dimension i(G), inequality 2n−m−i(G)−ce(G)≤2 holds. Moreover, the equality holds if and only if the so‐called zone graphs of G are trees. This answers the question from Bre r et al. [Tiled partial cubes, J Graph Theory 40 (2002) 91–103] whether partial cubes admit this kind of inequalities. It is also shown that a suggested inequality from Bre r et al. [Tiled partial cubes, J Graph Theory 40 (2002) 91–103] does not hold. Copyright © 2011 John Wiley & Sons, Ltd.
Triple therapy in hospitalized patients: Facts and controversies
Authors: Srour John Fani , Smetana Gerald W. 
Published: March 2011

AbstractThe use of triple therapy (warfarin plus dual antiplatelet therapy) has increased in recent years due to an aging population with a higher risk for atrial fibrillation, as well as the increased use of coronary stents for acute coronary syndromes. Triple therapy confers a higher bleeding risk than either warfarin or dual antiplatelet therapy alone. However, warfarin alone is inadequate for patients with indications for triple therapy because of an unacceptable risk of stent thrombosis, and dual antiplatelet therapy is inferior to warfarin for the prevention of ischemic strokes in patients with atrial fibrillation, mechanical valves, or intraventricular thrombosis. Hospitalists face the challenge of balancing the aforementioned risks; the optimal management of these patients requires knowledge of the relevant literature and expertise. In this paper, we review the current literature on antiplatelet and anticoagulant combinations in patients with atrial fibrillation and coronary stents in order to improve adherence to published guidelines and to reduce the risk of bleeding. Journal of Hospital Medicine 2011;. © 2011 Society of Hospital Medicine
Comparative effectiveness of pleural drainage procedures for the treatment of complicated pneumonia in childhood
Authors: Shah Samir S. , Hall Matthew , Newland Jason G. , Brogan Thomas V. , Farris Reid W. D. , Williams Derek J. , Larsen Gitte , Fine Bryan R. , Levin James E. , Wagener Jeffrey S. , Conway Patrick H. , Myers Angela L. 
Published: March 2011

AbstractOBJECTIVE:To determine the comparative effectiveness of common pleural drainage procedures for treatment of pneumonia complicated by parapneumonic effusion (ie, complicated pneumonia).DESIGN:Multicenter retrospective cohort study.SETTING:Forty children's hospitals contributing data to the Pediatric Health Information System.PARTICIPANTS:Children with complicated pneumonia requiring pleural drainage.MAIN EXPOSURES:Initial drainage procedures were categorized as chest tube without fibrinolysis, chest tube with fibrinolysis, video‐assisted thoracoscopic surgery (VATS), and thoracotomy.MAIN OUTCOME MEASURES:Length of stay (LOS), additional drainage procedures, readmission within 14 days of discharge, and hospital costs.RESULTS:Initial procedures among 3500 patients included chest tube without fibrinolysis (n = 1762), chest tube with fibrinolysis (n = 623), VATS (n = 408), and thoracotomy (n = 797). Median age was 4.1 years. Overall, 716 (20.5%) patients received an additional drainage procedure (range, 6.8–44.8% across individual hospitals). The median LOS was 10 days (range, 7–14 days across individual hospitals). The median readmission rate was 3.8% (range, 0.8%‐33.3%). In multivariable analysis, differences in LOS by initial procedure type were not significant. Patients undergoing initial chest tube placement with or without fibrinolysis were more likely to require additional drainage procedures. However, initial chest tube without fibrinolysis was the least costly strategy.CONCLUSION:There is variability in the treatment and outcomes of children with complicated pneumonia. Outcomes were similar in patients undergoing initial chest tube placement with or without fibrinolysis. Those undergoing VATS received fewer additional drainage procedures but had no differences in LOS compared with other strategies. Journal of Hospital Medicine 2011;. © 2011 Society of Hospital Medicine
Habitat‐specific trends in ontogeny of body shape in stickleback from coastal archipelago: Potential for rapid shifts in colonizing populations
Authors: Spoljaric M.A. , Reimchen T.E. 
Published: March 2011

AbstractWe investigated ontogenetic trends in body shape of 54 freshwater (48 lake, seven stream) and six anadromous populations of threespine stickleback (Gasterosteus aculeatusL.) from the Haida Gwaii archipelago off the west coast of Canada. Multivariate analysis of covariance on the partial warp scores generated from 12 homologous landmarks on 1,958 digital images of subadult and adult male stickleback indicated that there was considerable variability of population ontogenetic slopes. We used discriminant function analysis to quantify body shape and determined that anadromous stickleback, which are ancestral to the freshwater populations, have a strongly negative ontogenetic slope (−5.62; increased streamlining with increased size). All freshwater populations exhibit a more positive slope (91% differed significantly from the marine slope), with the differences being most accentuated in populations from ponds and streams. In pristine lakes, ontogenetic slope could be predicted by lake volume as well as multivariate measures of habitat. Evidence from field transplant experiments of one of the intact populations indicates a rapid change (5 years) from allometric to isometric growth, equivalent to about half of the total slope variation among intact populations on the archipelago. We interpret this shift as developmental plasticity and suggest this may comprise the precursor for selection of optimal body shapes in these stickleback populations. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.
Brain [U‐13C]glucose metabolism in mice with decreased α‐ketoglutarate dehydrogenase complex activity
Authors: Nilsen Linn Hege , Shi Qingli , Gibson Gary E. , Sonnewald Ursula 
Published: March 2011

AbstractThe activity of the α‐ketoglutarate dehydrogenase complex (KGDHC), a mitochondrial enzyme complex that mediates the oxidative decarboxylation of α‐ketoglutarate in the TCA cycle, is reduced in Alzheimer's disease. We investigated the metabolic effects of a partial KGDHC activity reduction on brain glucose metabolism using mice with disrupted expression of dihydrolipoyl succinyltransferase (DLST; gene encoding the E2k subunit of KGDHC). Brain tissue extracts from cortex and cerebellum of 6‐week‐old heterozygote DLST knockout mice (DLST+/−) and corresponding wild‐type mice injected with [U‐13C]glucose and decapitated 15 min later were analyzed. An increase in the concentration of glucose in cortex suggested a decrease in the cortical utilization of glucose in DLST+/− mice. Furthermore, the concentration and 13C labelling of aspartate in cortex were reduced in DLST+/− mice. This decline was likely caused by a decrease in the pool of oxaloacetate. In contrast to results from cell culture studies, no indications of altered glycolysis or GABA shunt activity were found. Glucose metabolism in the cerebellum was unaffected by the decrease in KGDHC activity. Among metabolites not related to glucose metabolism, the concentration of taurine was decreased in the cortex, and that of tyrosine was increased in the cerebellum. These results imply that diminished KGDHC activity has the potential to induce the reduction in glucose utilization that is seen in several neurodegenerative diseases. © 2011 Wiley‐Liss, Inc.
Structure factors of polyelectrolyte solutions revealed by neutron scattering
Authors: Jannink G. 
Published: March 2011

AbstractThe solute structure in concentrated polyelectrolyte solutions is discussed in terms of the following observations:1) The broad peak in the global structure function measured by radiation scattering (neutron, X rays or light), in the interval q < 2 nm−1,2) The separate intra and intermolecular structure functions obtained by neutron scattering,3) The separate polyion‐counterion partial structure factors derived from neutron scattering,4) The variation with wave vector of neutron and light quasi‐elastic broadening.
New reactive polymers containing nitrogen functionalities: From asymmetric synthesis to supported catalysis
Authors: Fréchet Jean M.J. , Deratani André , Darling Graham , Lecavalier Pierre , Li Nai Hong 
Published: March 2011

AbstractSeveral new reactive polymers containing various nitrogen functionalities have been prepared in bead form and tested as catalysts or ligands for reactive moieties in organic synthesis. In particular polymers containing 4‐dialkylaminopyridine pendant groups show good to excellent catalytic activities depending on their structure and their microenvironment. Best results are obtained on polystyrene backbones when the catalytic species are removed from the styrene rings by a three carbon spacer. Poly‐benzimidazole resins prepared by precipitation polymerization are good ligands for transition metal catalysts used in the catalytic hydrogenation of nitro compounds or olefinic double‐bonds. The PBI resins can also be used to prepare a polymeric oxidizing reagent through the binding of Cr(VI); the reagent oxidizes alcohols to the corresponding carbonyls while spent Cr(II) or Cr(III) remains anchored to the polymer. Other polymers containing chiral amino‐alcohol pendant groups show useful properties as chiral auxiliaries in the asymmetric reduction of ketones using polymer‐complexed lithium aluminium hydride.
Surface forces with adsorbed polymers: Direct measurements and model calculations
Authors: Klein Jacob 
Published: March 2011

AbstractWe Have Measured Directly The Forces Between Two Smooth Solid Surfaces Immersed In Liquid Media In The Range Of Surface Separation 0 ∼ 2000Å. By Measuring The Interactions Both With And Without Polymers Adsorbed Onto The Surfaces From The Solution, We Could Characterize The Effects Due To The Adsorbed Polymers Themselves. This Has Been Done For Several Model Polymer Systems In A Wide Range Of Solvency Conditions: Poor‐, Theta‐ And Good Solvents, As Well As For Charged Polymers In Ionic Media. The Present Paper Describes Two Recent Studies Of Adsorbed Polymers In Theta‐Solvent And Good Solvent Conditions, And The Effect Of Polymer Bridging At Low Adsorbance Values. The Experimental Studies Are Extremely Direct, And Can Be Compared With Molecular Models: We Briefly Describe Such A Detailed Comparison For The Case Of Interaction Between Adsorbed Polymer Layers In A poor solvent.