bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct patterns in the diurnal and seasonal variability in four components of soil respiration in a temperate forest under free-air CO2 enrichment
Authors: Taneva L. , Gonzalez-Meler M. A.
Published: October 2011

Abstract. Soil respiration (RS) is a major flux in the global carbon (C) cycle. Responses of RS to changing environmental conditions may exert a strong control on the residence time of C in terrestrial ecosystems and in turn influence the atmospheric concentration of greenhouse gases. Soil respiration consists of several components oxidizing soil C from different pools, age and chemistry. The mechanisms underlying the temporal variability of RS components are poorly understood. In this study, we used the long-term whole-ecosystem 13C tracer at the Duke Forest Free Air CO2 Enrichment site to separate forest RS into its autotrophic (RR) and heterotrophic components (RH). The contribution of RH to RS was further partitioned into litter decomposition (RL), and decomposition of soil organic matter (RSOM) of two age classes – up to 8 yr old and SOM older than 8 yr. Soil respiration was generally dominated by RSOM during the growing season (44% of daytime RS), especially at night. The contribution of heterotrophic respiration (RSOM and RL) to RS was not constant, indicating that the seasonal variability in RR alone cannot explain seasonal variation in RS. Although there was no diurnal variability in RS, there were significant compensatory differences in the contribution of individual RS components to daytime and nighttime rates. The average contribution of RSOM to RS was greater at night (54%) than during the day (44%). The average contribution of RR to total RS was ~30% during the day and ~34% during the night. In contrast, RL constituted 26% of RS during the day and only 12% at night. About 95% of the decomposition of soil C older than 8 yr (Rpre-tr) originated from RSOM and showed more pronounced and consistent diurnal variability than any other RS component; nighttime rates were on average 29% higher than daytime rates. In contrast, the decomposition of more recent, post-treatment C (Rpre-tr) did not vary diurnally. None of the diurnal variations in components of RH could be explained by only temperature and moisture variations. Our results indicate that the variation observed in the components of RS is the result of complex interaction between dominant biotic controls (e.g. plant activity, mineralization kinetics, competition for substrates) over abiotic controls (temperature, moisture). The interactions and controls among roots and other soil organisms that utilize C of different chemistry, accessibility and ages, results in the overall soil CO2 efflux. Therefore understanding the controls on the components of RS is necessary to elucidate the influence of ecosystem respiration on atmospheric C-pools at different time scales.
Carbon dynamics in the western Arctic Ocean: insights from full-depth carbon isotope profiles of DIC, DOC, and POC
Authors: Griffith D. R. , McNichol A. P. , Xu L. , McLaughlin F. A. , Macdonald R. W. , Brown K. A. , Eglinton T. I.
Published: October 2011

Abstract. Arctic warming is projected to continue throughout the coming century. Yet, our currently limited understanding of the Arctic Ocean carbon cycle hinders our ability to predict how changing conditions will affect local Arctic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-isotope profiles for dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and suspended particulate organic carbon (POCsusp) at two sites in the Canada Basin of the Arctic Ocean. The carbon isotope composition of sinking and suspended POC in the Arctic contrasts strongly with open ocean Atlantic and Pacific sites, pointing to a combination of inputs to Arctic POCsusp at depth, including surface-derived organic carbon (OC), sorbed/advected OC, and OC derived from in situ DIC fixation. The latter process appears to be particularly important at intermediate depths, where mass balance results suggest that OC derived from in situ DIC fixation contributes up to 22% of POCsusp. As in other oceans, surface-derived OC is still a dominant source to Arctic POCsusp. Yet, we suggest that significantly smaller vertical POC fluxes in the Canada Basin make it possible to see evidence of DIC fixation in the POCsusp pool even at the bulk isotope level.
Estimating geostatistical parameters and spatially-variable hydraulic conductivity within a catchment system using an ensemble smoother
Authors: Bailey R. T. , Baù D.
Published: October 2011

Abstract. Groundwater flow models are important tools in assessing baseline conditions and investigating management alternatives in groundwater systems. The usefulness of these models, however, is often hindered by insufficient knowledge regarding the magnitude and spatial distribution of the spatially-distributed parameters, such as hydraulic conductivity (K), that govern the response of these models. Proposed parameter estimation methods frequently are demonstrated using simplified aquifer representations, when in reality the groundwater regime in a given watershed is influenced by strongly-coupled surface-subsurface processes. Furthermore, parameter estimation methodologies that rely on a geostatistical structure of K often assume the parameter values of the geostatistical model as known or estimate these values from limited data. In this study, we investigate the use of a data assimilation algorithm, the Ensemble Smoother, to provide enhanced estimates of K within a catchment system using the fully-coupled, surface-subsurface flow model CATHY. Both water table elevation and streamflow data are assimilated to condition the spatial distribution of K. An iterative procedure using the ES update routine, in which geostatistical parameter values defining the true spatial structure of K are identified, is also presented. In this procedure, parameter values are inferred from the updated ensemble of K fields and used in the subsequent iteration to generate the K ensemble, with the process proceeding until parameter values are converged upon. The parameter estimation scheme is demonstrated via a synthetic three-dimensional tilted v-shaped catchment system incorporating stream flow and variably-saturated subsurface flow, with spatio-temporal variability in forcing terms. Results indicate that the method is successful in providing improved estimates of the K field, and that the iterative scheme can be used to identify the geostatistical parameter values of the aquifer system. In general, water table data have a much greater ability than streamflow data to condition K. Future research includes applying the methodology to an actual regional study site.
A possible theory for the interaction between convective activities and vortical flows
Authors: Zhao N. , Shen X. Y. , Ding Y. H. , Takahashi M.
Published: October 2011

Abstract. Theoretical studies usually attribute convections to the developments of instabilities such as the static or symmetric instabilities of the basic flows. However, the following three facts make the validities of these basic theories unconvincing. First, it seems that in most cases the basic flow with balance property cannot exist as the exact solution, so one cannot formulate appropriate problems of stability. Second, neither linear nor nonlinear theories of dynamical instability are able to describe a two-way interaction between convection and its background, because the basic state which must be an exact solution of the nonlinear equations of motion is prescribed in these issues. And third, the dynamical instability needs some extra initial disturbance to trigger it, which is usually another point of uncertainty. The present study suggests that convective activities can be recognized in the perspective of the interaction of convection with vortical flow. It is demonstrated that convective activities can be regarded as the superposition of free modes of convection and the response to the forcing induced by the imbalance of the unstably stratified vortical flow. An imbalanced vortical flow provides not only an initial condition from which unstable free modes of convection can develop but also a forcing on the convection. So, convection is more appropriately to be regarded as a spontaneous phenomenon rather than a disturbance-triggered phenomenon which is indicated by any theory of dynamical instability. Meanwhile, convection, particularly the forced part, has also a reaction on the basic flow by preventing the imbalance of the vortical flow from further increase and maintaining an approximately balanced flow.
N/P ratio of nutrient uptake in the Baltic Sea
Authors: Wan Z. , Jonasson L. , Bi H.
Published: October 2011

Abstract. The N/P ratio of nutrient uptake, the change of dissolved inorganic nitrogen (DIN) relative to the change of dissolved inorganic phosphorus (DIP), is a key parameter for many ecological models. In the Baltic Sea ecosystem, the N/P ratio of nutrient uptake varies among different basins and different seasons. The N/P ratio of nutrient alteration, i.e., the ratio of DIN to DIP altered before and after spring blooms, is not the same as the N/P ratio of nutrient uptake, but the former can be regarded as an indicator of the latter in the Baltic Sea. Based on the observed N/P ratio of nutrient alteration, we hypothesize a non-Redfield N/P ratio of nutrient uptake. The 3-D-ecosystem model ERGOM coupled with the circulation model DMI-BSHcmod was used to test this hypothesis. When the Redfield ratio was used in the model, the DIP surplus after spring blooms was too high and resulted in excessive growth of cyanobacteria and too much nitrogen fixation. When the non-Redfield ratio was used in the model, these problems tended to disappear. In summary, we show that: (1) the Redfield N/P ratio of nutrient uptake in the Baltic Sea tends to be too high; (2) a N/P ratio of 10:1 appears to work better than the Redfield value; and (3) the N/P ratio of nutrient uptake in the Baltic Proper during spring blooms is around 6:1. As the model limitation using one identical value for two N/P ratios for nutrient uptake and remineralization, the quantitative conclusions are only convincing as a model parameter even though it obviously improves model predictions. Whether this model parameter is consistent with the biological nutrient uptake is worth being further verified with some laboratory investigations or simulations using a more sophisticated model with independent N/P ratios for nutrient uptake and remineralization.
Annual cycles of chlorophyll-a, non-algal suspended particulate matter, and turbidity observed from space and in-situ in coastal waters
Authors: Gohin F.
Published: October 2011

Abstract. Sea surface temperature, chlorophyll, and turbidity are three variables of the coastal environment commonly measured by monitoring networks. The observation networks are often based on coastal stations, which do not provide a sufficient coverage to validate the model outputs or to be used in assimilation over the continental shelf. Conversely, the products derived from satellite reflectance generally show a decreasing quality shoreward, and an assessment of the limitation of these data is required. The annual cycle, mean, and percentile 90 of the chlorophyll concentration derived from MERIS/ESA and MODIS/NASA data processed with a dedicated algorithm have been compared to in-situ observations at twenty-six selected stations from the Mediterranean Sea to the North Sea. Keeping in mind the validation, the forcing, or the assimilation in hydrological, sediment-transport, or ecological models, the non-algal Suspended Particulate Matter (SPM) is also a parameter which is expected from the satellite imagery. However, the monitoring networks measure essentially the turbidity and a consistency between chlorophyll, representative of the phytoplankton biomass, non-algal SPM, and turbidity is required. In this study, we derive the satellite turbidity from chlorophyll and non-algal SPM with a common formula applied to in-situ or satellite observations. The distribution of the satellite-derived turbidity exhibits the same main statistical characteristics as those measured in-situ, which satisfies the first condition to monitor the long-term changes or the large-scale spatial variation over the continental shelf and along the shore. For the first time, climatologies of turbidity, so useful for mapping the environment of the benthic habitats, are proposed from space on areas as different as the southern North Sea or the western Mediterranean Sea, with validation at coastal stations.
Worldwide widespread decadal-scale decrease of glacier speed revealed using repeat optical satellite images
Authors: Heid T. , Kääb A.
Published: October 2011

Abstract. Matching of repeat optical satellite images to derive glacier velocities is an approach that is much used within glaciology. Lately, focus has been put into developing, improving, automating and comparing different image matching methods. This makes it now possible to investigate glacier dynamics within large regions of the world and also between regions to improve knowledge about glacier dynamics in space and time. In this study we investigate whether the negative glacier mass balance seen over large parts of the world has caused the glaciers to change their speeds. The studied regions are Pamir, Caucasus, Penny Ice Cap, Alaska Range and Patagonia. In addition we derive speed changes for Karakoram, a region assumed to have positive mass balance and that contains many surge-type glaciers. We find that the mapped glaciers in the five regions with negative mass balance have decreased their speeds over the last decades, Pamir by 43 % in average per decade, Caucasus by 8 % in average per decade, Penny Ice Cap by 25 % in average per decade, Alaska Range by 11 % in average per decade and Patagonia by 20 % in average per decade. Glaciers in Karakoram have generally increased their speeds, but surging glaciers and glaciers with flow instabilities are most prominent in this area.
Flexural Behavior of Reinforced High-Performance Concrete Beams Made with Steel Slag Coarse Aggregate
Authors: Zaki Saaid I. , Metwally Ibrahim M. , El-Betar Sameh A.
Published: October 2011

In recent years, an emerging technology termed high-performance concrete (HPC) has become popular in construction industry. The constituent materials of HPC depend on the desired characteristics and the availability of suitable local economic alternatives. One of these alternatives is steel slag waste material. It is an industrial by-product waste particles resulted from reinforcing steel bars manufacture, its production is very huge; total quantity produced from all steel rebars manufacture factories in Egypt is nearly million tons/year. HPC made with steel slag aggregate (SSA) is considered as green concrete, using of steel-slag as a coarse aggregate increases the probability of consuming such large accumulations of slag (in HPC industry) which they represent as a waste and polluted material in environment. A total of eight under, balanced and over reinforced concrete beams were fabricated and tested. RC beams were made with HPC having compressive strength of 58.1 and 75.6 MPa and tensile reinforcement ratio in the range of 0.90 to 4.3%. Data presented concentrated on the chemical, physical, and mechanical properties of the used new material (SSA) and the flexural behavior of reinforced high-performance concrete beams made with steel slag coarse aggregate (RHPC-SSA) beams. It was observed that the RHPC-SSA beams can give satisfactory structural performance according to the American and Egyptian Building Codes.
Linearization of Two Second-Order Ordinary Differential Equations via Fiber Preserving Point Transformations
Authors: Sookmee Sakka , Meleshko Sergey V.
Published: October 2011

The necessary form of a linearizable system of two second-order ordinary differential equations y1″=f1(x,y1,y2,y1′,y2′), y2″=f2(x,y1,y2,y1′,y2′) is obtained. Some other necessary conditions were also found. The main problem studied in the paper is to obtain criteria for a system to be equivalent to a linear system with constant coefficients under fiber preserving transformations. A linear system with constant coefficients is chosen because of its simplicity in finding the general solution. Examples demonstrating the procedure of using the linearization theorems are presented.
Liquid Crystal-Based Reconfigurable Tunable Filter with DBR Topology
Authors: Missaoui S. , Kaddour M.
Published: October 2011

The use of liquid crystals for tunable filter in planar technology is proposed. The design is based on a dual-behavior resonator (DBR) topology. These resonators are based on the association of different parallel open-ended stubs and allow the designer to independently control the in-band and out-of-band responses of the filter. To benefit from liquid crystal anisotropy and thus obtain agility, a bias voltage is applied. The simulated results are compared with measured data, and good agreement is obtained.
Epoxy Ring Opening Phase Transfer as a General Route to Water Dispersible Superparamagnetic Fe3O4 Nanoparticles and Their Application as Positive MRI Contrast Agents
Authors: Ninjbadgar Tsedev , Brougham Dermot F.
Published: October 2011

A novel and efficient method to produce water dispersible superparamagnetic Fe3O4 nanoparticles is described. Nanoparticles prepared by non‐hydrolytic organic phase methods are subsequently functionalized with (3‐glycidyloxypropyl)trimethoxysilane, a linker that prevents aggregation and is available for subsequent coupling reactions with a wide range of polymers and biomolecules. Ring opening coupling reactions were used to coat the epoxy‐functionalized magnetite nanoparticles with aminated polymers (polyetheramines) or small molecules (arginine). The resulting nanoparticles, with hydrodynamic size of 13 nm, are found to be very stable over extended periods in water or PBS due to the presence of a dense stabilizer layer covalently anchored to the surface. Exceptionally high spin‐lattice relaxivity, r1, values of 17 s−1 mM−1, and low r2/r1 ratios of 3.3–3.8 were exhibited in the clinical MRI frequency range, irrespective of the molecule selected for nanoparticle stabilization. As a result the dispersions are excellent candidates for incorporation into multi‐functional assemblies or for use as positive contrast agent for MRI.
Merocyanine/C60 Planar Heterojunction Solar Cells: Effect of Dye Orientation on Exciton Dissociation and Solar Cell Performance
Authors: Ojala Antti , Petersen Andreas , Fuchs Andreas , Lovrincic Robert , Pölking Carl , Trollmann Jens , Hwang Jaehyung , Lennartz Christian , Reichelt Helmut , Höffken Hans Wolfgang , Pucci Annemarie , Erk Peter , Kirchartz Thomas , Würthner Frank
Published: October 2011

In this study the charge dissociation at the donor/acceptor heterointerface of thermally evaporated planar heterojunction merocyanine/C60 organic solar cells is investigated. Deposition of the donor material on a heated substrate as well as post‐annealing of the complete devices at temperatures above the glass transition temperature of the donor material results in a twofold increase of the fill factor. An analytical model employing an electric‐field‐dependent exciton dissociation mechanism reveals that geminate recombination is limiting the performance of as‐deposited cells. Fourier‐transform infrared ellipsometry shows that, at temperatures above the glass transition temperature of the donor material, the orientation of the dye molecules in the donor films undergoes changes upon annealing. Based on this finding, the influence of the dye molecules’ orientations on the charge‐transfer state energies is calculated by quantum mechanical/molecular mechanics methods. The results of these detailed studies provide new insight into the exciton dissociation process in organic photovoltaic devices, and thus valuable guidelines for designing new donor materials.
Mechanical behavior of areca fiber reinforced epoxy composites
Authors: Venkateshappa Srinivasa Chikkol , Jayadevappa Suresh Yalaburgi , Puttiah Prema Kumar Wooday
Published: October 2011

In the present work, the mechanical properties of composites obtained by using areca fibers in epoxy matrix have been investigated. The areca fibers extracted from the areca husk are alkali‐treated with potassium hydroxide to get better interfacial bonding between fibers and matrix. The test specimens are prepared with different values of weight ratio of fiber to matrix, the fibers being randomly oriented. The test specimens are cured for different periods of time to study the effect of curing time on the mechanical properties. The results of tests such as water absorption, tension, compression, bending, impact, and hardness conducted on the test specimens are herein reported. It is found that the mechanical properties of the composites tested are greatly influenced by (i) alkali treatment of fiber, (ii) weight ratio of fiber–matrix, and (iii) curing time. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 31: 319–330, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20255
A dynamic buildup growth model for magnetic particle accumulation on single wires in high‐gradient magnetic separation
Authors: Chen Fei , Smith Kenneth A. , Hatton T. Alan
Published: October 2011

Magnetic fluids containing nano or submicron magnetic particles and their applications to food, biological, and pharmaceutical systems have recently attracted considerable attention. Magnetic particles can be collected efficiently in magnetizable matrices (e.g., iron wires) in high‐gradient magnetic separation processes. However, capture efficiencies based on results for clean, particle‐free, wires may be seriously in error because the particle accumulation on the wire distorts the flow and the magnetic fields, and thus influences the capture efficiency. A model is developed here in which the dynamic growth process is treated as a moving boundary problem, with the growing front tracked explicitly by marker points distributed evenly over its surface. The flow field and magnetic field are calculated using a finite element method, and a particle trajectory model is used to calculate the deposition flux on the surface. The marker point distribution and the buildup shape are updated at each simulation step. Simulation results show that, for weakly magnetic particles, the accumulation exhibits a smoothly growing front, whereas for strongly magnetic particles, an instability occurs, leading to dendritic growth. The capture efficiency decreases dramatically as particle accumulation increases; and this trend is more prominent for the transverse configuration than it is for the longitudinal configuration. The simulation results show good agreement with experimental results from the literature. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Early postoperative care following endoscopic sinus surgery: an evidence‐based review with recommendations
Authors: Rudmik Luke , Soler Zachary M. , Orlandi Richard R. , Stewart Michael G. , Bhattacharyya Neil , Kennedy David W. , Smith Timothy L.
Published: October 2011

Background:

Early postoperative care following endoscopic sinus surgery (ESS) has been suggested to minimize avoidable complications and optimize long‐term outcomes. Several postoperative care strategies have been proposed but a formal comprehensive evaluation of the evidence has never been performed. The purpose of this article is to provide an evidence‐based approach to early postoperative care following ESS.

Methods:

A systematic review of the literature was performed and the Clinical Practice Guideline Manual, Conference on Guideline Standardization (COGS), and the Appraisal of Guidelines and Research Evaluation (AGREE) instrument recommendations were followed. Study inclusion criteria were: adult population >18 years old; chronic rhinosinusitis (CRS) based on published diagnostic criteria; ESS following failed medical therapy; primary study objective was to evaluate an ESS early postoperative care strategy; and clearly defined primary clinical end‐point.

Results:

This review identified and evaluated the literature on 7 early postoperative care strategies following ESS: saline irrigations, sinus cavity debridements, systemic steroids, topical steroids, oral antibiotics, topical decongestants, and drug‐eluting spacers/stents.

Conclusion:

Based on the available evidence, use of nasal saline irrigation, sinus cavity debridement, and standard topical nasal steroid spray are recommended early postoperative care interventions. Postoperative antibiotic, systemic steroid, nonstandard topical nasal steroid solution, and/or drug‐eluting spacers/stents are options in postoperative management. These evidence‐based recommendations should not necessarily be applied to all postoperative patients and clinical judgment, in addition to evidence, is critical to determining the most appropriate care. © 2011 ARS‐AAOA, LLC.
Anti–Aquaporin‐4 monoclonal antibody blocker therapy for neuromyelitis optica
Authors: Tradtrantip Lukmanee , Zhang Hua , Saadoun Samira , Phuan Puay‐Wah , Lam Chiwah , Papadopoulos Marios C. , Bennett Jeffrey L. , Verkman A. S.
Published: October 2011

Objective:

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system. Circulating autoantibodies (NMO‐immunoglobulin [Ig]G) against astrocyte water channel aquaporin‐4 (AQP4) cause complement‐ and cell‐mediated astrocyte damage with consequent neuroinflammation and demyelination. Current NMO therapies, which have limited efficacy, include immunosuppression and plasma exchange. The objective of this study was to develop a potential new NMO therapy based on blocking of pathogenic NMO‐IgG binding to its target, AQP4.

Methods:

We generated nonpathogenic recombinant monoclonal anti‐AQP4 antibodies that selectively block NMO‐IgG binding to AQP4. These antibodies comprise a tight‐binding anti‐AQP4 Fab and a mutated Fc that lacks functionality for complement‐ and cell‐mediated cytotoxicity. The efficacy of the blocking antibodies was studied using cell culture, spinal cord slice, and in vivo mouse models of NMO.

Results:

In AQP4‐expressing cell cultures, the nonpathogenic competing antibodies blocked binding of NMO‐IgG in human sera, reducing to near zero complement‐ and cell‐mediated cytotoxicity. The antibodies prevented the development of NMO lesions in an ex vivo spinal cord slice model of NMO and in an in vivo mouse model, without causing cytotoxicity.

Interpretation:

Our results provide proof of concept for a therapy of NMO with blocking antibodies. The broad efficacy of antibody inhibition is likely due to steric competition because of its large physical size compared to AQP4. Blocker therapy to prevent binding of pathogenic autoantibodies to their targets may be useful for treatment of other autoimmune diseases as well. ANN NEUROL 2012;
Increased gene dosage of myelin protein zero causes Charcot‐Marie‐Tooth disease
Authors: Maeda Meiko Hashimoto , Mitsui Jun , Soong Bing‐Wen , Takahashi Yuji , Ishiura Hiroyuki , Hayashi Shin , Shirota Yuichiro , Ichikawa Yaeko , Matsumoto Hideyuki , Arai Makoto , Okamoto Tomoko , Miyama Sahoko , Shimizu Jun , Inazawa Johji , Goto Jun , Tsuji Shoji
Published: October 2011

Objective:

On the basis of the hypothesis that copy number mutations of the genes encoding myelin compact proteins are responsible for myelin disorders in humans, we have explored the possibility of copy number mutations in patients with Charcot‐Marie‐Tooth disease (CMT) whose responsible genes remain undefined.

Methods:

A family with 6 affected members in 3 consecutive generations, presenting with motor and sensory demyelinating polyneuropathy, was investigated. Characteristic clinical features in this pedigree include Adie pupils and substantial intrafamilial variability in the age at onset, electrophysiological findings, and clinical severity. Nucleotide sequence analyses of PMP22, MPZ, or GJB1 and gene dosage study of PMP22 did not reveal causative mutations. Hence, we applied a custom‐designed array for comparative genomic hybridization (CGH) analysis to conduct a comprehensive screening of copy number mutations involving any of the known causative genes for CMT other than PMP22.

Results:

The array CGH analyses revealed increased gene dosage involving the whole MPZ, and the flanking genes of SDHC and C1orf192. The gene dosage is estimated to be 5 copies. This mutation showed complete cosegregation with the disease phenotype in this pedigree.

Interpretation:

The increased gene dosage of MPZ and increased expression level of MPZ mRNA emphasize the important role of the dosage of the MPZ protein in the functional integrity of peripheral nerve myelin in humans, and provide a new insight into the pathogenic mechanisms underlying CMT. ANN NEUROL 2012;71:84–92
Characterization and antioxidative properties of condensed tannins from the mangrove plant Aegiceras corniculatum
Authors: Wei Shu‐Dong , Lin Yi‐Ming , Liao Meng‐Meng , Zhou Hai‐Chao , Li Yuan‐Yue
Published: October 2011

Freeze‐dried leaf, stem bark, and root bark powders of Aegiceras corniculatum were extracted with three different types of polar solvents: methanol, ethyl acetate, and water. The methanol extracts had the highest concentrations in total phenolics and extractable condensed tannins, followed by water and ethyl acetate extracts. Analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) suggested that condensed tannins from leaf, stem bark, and root bark contained prodelphinidins and procyanidins, with the predominance of prodelphinidins and high level of galloylation. Acid‐catalyzed degradation in the presence of benzyl mercaptan indicated that gallocatechin, epigallocatechin, epigallocatechin‐3‐O‐gallate, and epicatechin‐3‐O‐gallate occurred as the terminal units and (epi)gallocatechin, (epi)gallocatechin‐3‐O‐gallate, (epi)catechin, and (epi)catechin‐3‐O‐gallate occurred as the extension units. The mean degrees of polymerization (mDP) of condensed tannins from leaf, stem bark, and root bark were 13.5, 7.4, and 12.3, respectively. The condensed tannins from leaf and stem bark exhibited a higher DPPH radical scavenging activity and ferric reducing/antioxidant power compared to that of synthetic antioxidant butylated hydroxyanisole (BHA). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Employing document dependency in blog search
Authors: Keikha Mostafa , Crestani Fabio , Carman Mark James
Published: October 2011

The goal in blog search is to rank blogs according to their recurrent relevance to the topic of the query. State‐of‐the‐art approaches view it as an expert search or resource selection problem. We investigate the effect of content‐based similarity between posts on the performance of the retrieval system. We test two different approaches for smoothing (regularizing) relevance scores of posts based on their dependencies. In the first approach, we smooth term distributions describing posts by performing a random walk over a document‐term graph in which similar posts are highly connected. In the second, we directly smooth scores for posts using a regularization framework that aims to minimize the discrepancy between scores for similar documents. We then extend these approaches to consider the time interval between the posts in smoothing the scores. The idea is that if two posts are temporally close, then they are good sources for smoothing each other's relevance scores. We compare these methods with the state‐of‐the‐art approaches in blog search that employ Language Modeling‐based resource selection algorithms and fusion‐based methods for aggregating post relevance scores. We show performance gains over the baseline techniques which do not take advantage of the relation between posts for smoothing relevance estimates.
Mapping world scientific collaboration: Authors, institutions, and countries
Authors: Gazni Ali , Sugimoto Cassidy R. , Didegah Fereshteh
Published: October 2011

International collaboration is being heralded as the hallmark of contemporary scientific production. Yet little quantitative evidence has portrayed the landscape and trends of such collaboration. To this end, 14,000,000 documents indexed in Thomson Reuters's Web of Science (WoS) were studied to provide a state‐of‐the‐art description of scientific collaborations across the world. The results indicate that the number of authors in the largest research teams have not significantly grown during the past decade; however, the number of smaller research teams has seen significant increases in growth. In terms of composition, the largest teams have become more diverse than the latter teams and tend more toward interinstitutional and international collaboration. Investigating the size of teams showed large variation between fields. Mapping scientific cooperation at the country level reveals that Western countries situated at the core of the map are extensively cooperating with each other. High‐impact institutions are significantly more collaborative than others. This work should inform policy makers, administrators, and those interested in the progression of scientific collaboration.
Energetic Salts Based on Dipicrylamine and Its Amino Derivative
Authors: Huang Haifeng , Zhou Zhiming , Song Jinhong , Liang Lixuan , Wang Kai , Cao Dan , Sun Wenwen , Dong Xuemin , Xue Min
Published: October 2011

Energetic salts based on dipicrylamine and its amino derivative were synthesized. All salts were fully characterized by multinuclear NMR spectroscopy (1H, 13C), vibrational spectroscopy (IR), and elemental analysis. Ethylenediammonium di‐DPA (DPA=dipicrylamine) and 1,3‐diaminoguanidinium DPA were further confirmed by single‐crystal X‐ray diffraction. These salts exhibit reasonable physical properties, such as high densities (1.71–1.81 g cm−3), good thermal stabilities (Td=155–285 °C), and low solubilities in water. The impact sensitivity of 1‐methyl‐3,4,5‐triamino‐1,2,4‐triazolium DPA is lower than that of 2,4,6‐trinitrotoluene (TNT), and for some other energetic salts their impact sensitivities are comparable to that of TNT. Based on experimental densities and theoretical calculations carried out by using the Gaussian 03 suite of programs, all the salts have calculated detonation pressures (22.5–27.8 GPa) and velocities (7226–7917 m s−1) that exceed those of conventional TNT. The toxicities of these salts measured by luminescent bacteria toxicity tests are much lower than that of TNT, and two binary eutectic mixtures with melting points that fall between 70 and 100 °C were identified.
Structures and Stabilities of Group 13 Adducts [(NHC)(EX3)] and [(NHC)2(E2Xn)] (E=B to In; X=H, Cl; n=4, 2, 0; NHC=N‐Heterocyclic Carbene) and the Search for Hydrogen Storage Systems: A Theoretical Study
Authors: Holzmann Nicole , Stasch Andreas , Jones Cameron , Frenking Gernot
Published: October 2011

Quantum chemical calculations using density functional theory at the BP86/TZVPP level and ab initio calculations at the SCS‐MP2/TZVPP level have been carried out for the group 13 complexes [(NHC)(EX3)] and [(NHC)2(E2Xn)] (E=B to In; X=H, Cl; n=4, 2, 0; NHC=N‐heterocyclic carbene). The monodentate Lewis acids EX3 and the bidentate Lewis acids E2Xn bind N‐heterocyclic carbenes rather strongly in donor–acceptor complexes [(NHC)(EX3)] and [(NHC)2(E2Xn)]. The equilibrium structures of the bidentate complexes depend on the electronic reference state of E2Xn, which may vary for different atoms E and X. All complexes [(NHC)2(E2X4)] possess Cs symmetry in which the NHC ligands bind in a trans conformation to the group 13 atoms E. The complexes [(NHC)2(E2H2)] with E=B, Al, Ga have also Cs symmetry with a trans arrangement of the NHC ligands and a planar CE(H)E(H)C moiety that has a EE π bond. In contrast, the indium complex [(NHC)2(In2H2)] has Ci symmetry with pyramidal‐coordinated In atoms in which the hydrogen atoms are twisted above and below the CInInC plane. The latter Ci form is calculated for all chloride systems [(NHC)2(E2Cl2)], but the boron complex [(NHC)2(B2Cl2)] deviates only slightly from Cs symmetry. The B2 fragment in the linear coordinated complex [(NHC)2(B2)] has a highly excited (3)1Σg− reference state, which gives an effective B≡B triple bond with a very short interatomic distance. The heavier homologues [(NHC)2(E2)] (E=Al to In) exhibit a anti‐periplanar arrangement of the NHC ligands in which the E2 fragments have a (1)1Δg reference state and an EE double bond. The calculated energies suggest that the dihydrogen release from the complexes [(NHC)(EH3)] and [(NHC)2(E2Hn)] becomes energetically more favourable when atom E becomes heavier. The indium complexes should therefore be the best candidates of the investigated series for hydrogen‐storage systems that could potentially deliver dihydrogen at close to ambient temperature. The hydrogenation reaction of the dimeric magnesium(I) compound [LMgMgL] (L=β‐diketiminate) with [(NHC)(EH3)] becomes increasingly exothermic with the trend B<Al<Ga<In.
Temporal and spatial expression of CCN3 during retina development
Authors: Laurent Maryvonne , Le Dréau Gwenvaël , Guillonneau Xavier , Lelièvre Elise , Slembrouck Amélie , Goureau Olivier , Martinerie Cécile , Marx Maria
Published: October 2011

NOV/CCN3 is one of the founding members of the CCN (Cyr61 CTGF NOV) family. In the avian retina, CCN3 expression is mostly located within the central region of the inner nuclear layer. As retinal development progresses and this retinal layer differentiates and matures, CCN3 expression forms a dorsal–ventral and a central–peripheral gradient. CCN3 is produced by two glial cell types, peripapillary cells and Müller cells, as well as by horizontal, amacrine, and bipolar interneurons. In retinal neurons and Müller cell cultures, CCN3 expression is induced by activated BMP signaling, whereas Notch signaling decreases CCN3 mRNA and protein levels in Müller cells and has no effect in retinal neurons. In Müller cells, the CCN3 expression detected may thus result from a balance between the Notch and BMP signaling pathways. © 2011 Wiley Periodicals, Inc. Develop Neurobiol, 2012
Enantioselective Total Syntheses of (–)‐Isonitramine, (–)‐Sibirine, and (+)‐Nitramine by Ring‐Closing Metathesis
Authors: Pandey Ganesh , Prasanna Kumara C. , Kumar Burugu Shiva , Puranik Vedavati G.
Published: October 2011

Concise enantioselective total syntheses of naturally occurring 2‐azaspiro[5,5]undecan‐7‐ol (Nitraria) alkaloids viz. (–)‐isonitramine, (–)‐sibirine, and (+)‐nitramine are accomplished in 42, 38, and 25 % overall yield, respectively, in six steps starting from enantiomerically pure (S)‐methyl 3‐allyl‐2‐oxo‐1,2,3,6‐tetrahydropyridine‐3‐carboxylate (>99 % ee). The key feature of the syntheses involves diastereoselective Hosomi–Sakurai allylation followed by ring‐closing metathesis.
Surface instability of a thin electrolyte film undergoing coupled electroosmotic and electrophoretic flows in a microfluidic channel
Authors: Ray Bahni , Reddy Puchalapalli Dinesh Sankar , Bandyopadhyay Dipankar , Joo Sang W. , Sharma Ashutosh , Qian Shizhi , Biswas Gautam
Published: October 2011

We consider the stability of a thin liquid film with a free charged surface resting on a solid charged substrate by performing a general Orr–Sommerfeld (O‐S) analysis complemented by a long‐wave (LW) analysis. An externally applied field generates an electroosmotic flow (EOF) near the solid substrate and an electrophoretic flow (EPF) at the free surface. The EPF retards the EOF when both the surfaces have the same sign of the potential and can even lead to the flow reversal in a part of the film. In conjunction with the hydrodynamic stress, the Maxwell stress is also considered in the problem formulation. The electrokinetic potential at the liquid–air and solid–liquid interfaces is modelled by the Poisson–Boltzmann equation with the Debye–Hückel approximation. The O‐S analysis shows a finite‐wavenumber shear mode of instability when the inertial forces are strong and an LW interfacial mode of instability in the regime where the viscous force dominates. Interestingly, both the modes are found to form beyond a critical flow rate. The shear (interfacial) mode is found to be dominant when the film is thick (thin), the electric field applied is strong (weak), and the zeta‐potentials on the liquid–air and solid–liquid interfaces are high (small). The LW analysis predicts the presence of the interfacial mode, but fails to capture the shear mode. The change in the propagation direction of the interfacial mode with the zeta‐potential is predicted by both O‐S and LW analyses. The parametric range in which the LW analysis is valid is thus demonstrated.
Field experiments constraining the probability distribution of particle travel distances during natural rainstorms on different slope gradients
Authors: Ghahramani Afshin , Yoshiharu Ishikawa , Mudd Simon M.
Published: October 2011

Rain splash erosion is an important soil transport mechanism on steep hillslopes. The rain splash process is highly stochastic; here we seek to constrain the probability distribution of splash transport distances on natural hillslopes as a function of hillslope gradient and total precipitation depth. Field experiments were conducted under natural precipitation events to observe splash travel on varying slope gradients. The downslope fraction of splash transport on 15°, 25° and 33° gradients were 85%, 96% and 96%, respectively. Maximum splash transport (Lmax) was related to the rain splash detachment of soil particles and slope gradient. An empirical relationship of Lmax to the precipitation depth and gradient was obtained; it is linearly proportional to hillslope gradient and logarithmically related to precipitation depth. Measured splash distances were calibrated to the fully two‐dimensional (2D) model of splash transport of Furbish et al. (Journal of Geophysical Research 112: F01001, 2007) that is based on the assumption that radial splash distances are exponentially distributed; calibrated values of mean splash transport distances are an order of magnitude greater than those previously determined in a controlled laboratory setting. We also compared measured data with several one‐dimensional (1D) probability distributions to asses if splash transport distances could be better explained by a heavy‐tailed probability distribution rather than an exponential probability distribution. We find that for hillslopes of 15° and 25°, although a log‐normal probability distribution best describes the data, we find its likelihood is nearly indistinguishable from an exponential distribution based on computing maximum likelihood estimators for all 1D distributions (exponential, log‐normal and Weibull). At 33°, however, we find stronger evidence that measured travel distances are heavy‐tailed. Copyright © 2011 John Wiley & Sons, Ltd.
NSCLC: novel targeted therapies offer hope for the future
Authors: Nicolson Marianne , Dahle‐Smith Asa
Published: October 2011

Lung cancer remains a major healthcare challenge despite the recent reduction in incidence in the Western world and introduction of the public smoking ban in some countries. However, the complexity of tumour biology is being unravelled along with a greater understanding of molecular signalling pathways, opening up a new field of research into targeted therapies. Here the authors focus on non‐small cell lung cancer (NSCLC), discussing its current management and some of the promising targeted therapies currently being investigated. Copyright © 2011 John Wiley & Sons, Ltd.
Promising new inotropes for the treatment of heart failure
Authors: Lumb Joanna
Published: October 2011

Positive news on the development of second‐generation inotropes for treating heart failure was reported at the annual British Cardiovascular Society conference in June. Copyright © 2011 John Wiley & Sons, Ltd.
Bipolar I disorder: current and future management options
Authors: Maron Eduard , Young Allan H
Published: October 2011

Bipolar I disorder affects around one in every 100 adults and is a major public health issue. It is usually characterised by a combination of manic and depressive symptoms, with severe episodes of mood disturbance that can last for weeks or even months. Both men and women are affected, and the condition is a debilitating one that can adversely influence all areas of a person's life and his/her normal functioning. In this article, the authors look at the disease and its causes, and discuss both current and promising future treatment options. Copyright © 2011 John Wiley & Sons, Ltd.
Brain plasticity for verbal and visual memories in patients with mesial temporal lobe epilepsy and hippocampal sclerosis: An fMRI study
Authors: Alessio Andréa , Pereira Fabricio R.S. , Sercheli Maurício S. , Rondina Jane M. , Ozelo Helka B. , Bilevicius Elisabeth , Pedro Tatiane , Covolan Roberto J.M. , Damasceno Benito P. , Cendes Fernando
Published: October 2011

We aimed to identify the brain areas involved in verbal and visual memory processing in normal controls and patients with unilateral mesial temporal lobe epilepsy (MTLE) associated with unilateral hippocampal sclerosis (HS) by means of functional magnetic resonance imaging (fMRI). The sample comprised nine normal controls, eight patients with right MTLE, and nine patients with left MTLE. All subjects underwent fMRI with verbal and visual memory paradigms, consisting of encoding and immediate recall of 17 abstract words and 17 abstract drawings. A complex network including parietal, temporal, and frontal cortices seems to be involved in verbal memory encoding and retrieval in normal controls. Although similar areas of activation were identified in both patient groups, the extension of such activations was larger in the left‐HS group. Patients with left HS also tended to exhibit more bilateral or right lateralized encoding related activations. This finding suggests a functional reorganization of verbal memory processing areas in these patients due to the failure of left MTL system. As regards visual memory encoding and retrieval, our findings support the hypothesis of a more diffuse and bilateral representation of this cognitive function in the brain. Compared to normal controls, encoding in the left‐HS group recruited more widespread cortical areas, which were even more widespread in the right‐HS group probably to compensate for their right mesial temporal dysfunction. In contrast, the right‐HS group exhibited fewer activated areas during immediate recall than the other two groups, probably related to their greater difficulty in dealing with visual memory content. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.