bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Hollow BiVO4/Ag Composite Microspheres and Their Photocatalytic and Surface‐Enhanced Raman Scattering Properties
Authors: Chen Limiao , Yu Yifan , Wu Min , Huang Jianhan , Liu Younian , Liu Xiaohe , Qiu Guanzhou 
Published: February 2015

AbstractHollow BiVO4 microspheres are prepared in the presence of ethylenediaminetetraacetic acid (EDTA) through a hydrothermal method, and used as a template for the fabrication of Ag‐nanoparticle‐decorated BiVO4 (BiVO4/Ag) composite microspheres. The morphology and structure are characterized by transmission electron microscopy and scanning electron microscopy. It is found that EDTA plays an important role in the formation of the hollow microspheres, and the possible formation mechanism is discussed. UV/visible spectrometry analysis shows that the BiVO4/Ag composite microspheres exhibit a distinct surface plasmon absorption band compared with pure BiVO4 microspheres. The photocatalytic activities of the BiVO4/Ag composite microspheres are examined by studying the degradation of rhodamine 6G (R6G) solutions under visible‐light irradiation (>400 nm). The results show clearly that the BiVO4/Ag composite microspheres possess a much higher photocatalytic activity than pure BiVO4 microspheres and P25. In addition, Raman analyses show that the BiVO4/Ag composite microspheres exhibit an excellent surface‐enhanced Raman scattering (SERS) performance.
Controlled Oriented Attachment of Bipyramidal‐Shaped Anatase TiO2 and Their Enhanced Performance in Dye‐Sensitized Solar Cells
Authors: Yang Shuang , Zheng Yi Chu , Hou Yu , Yang Hua Gui 
Published: February 2015

AbstractA low‐cost hydrothermal method was used to synthesize high‐purity bipyramidal single‐crystals of TiO2 enclosed with high percentage of (101) facets. The oriented attachment behavior can be controlled by fine tuning the reaction temperature. This played an important role in determining the crystal growth along [001] direction resulting in the self‐assembly of the bipyramid crystals into connected ones to form single‐crystal nanrods without the loss of surface area. In addition, the relationship between oriented attachment and the photovoltaic performance of such anatase TiO2 nanocrystals in photoanodes of DSCs was investigated. The highly oriented sample reached a maximum overall energy conversion efficiency of 8.63 %. These results further illustrated that the highly oriented samples have superior charge transport ability derived from the enhanced long‐range atomic arrangement with reduced grain boundaries and comparable uptake of dye molecules.
Carbon‐Supported Base Metal Nanoparticles: Cellulose at Work
Authors: Hoekstra Jacco , Versluijs‐Helder Marjan , Vlietstra Edward J. , Geus John W. , Jenneskens Leonardus W. 
Published: February 2015

AbstractPyrolysis of base metal salt loaded microcrystalline cellulose spheres gives a facile access to carbon‐supported base metal nanoparticles, which have been characterized with temperature‐dependent XRD, SEM, TEM, ICP‐MS and elemental analysis. The role of cellulose is multifaceted: 1) it facilitates a homogeneous impregnation of the aqueous base metal salt solutions, 2) it acts as an efficacious (carbonaceous) support material for the uniformly dispersed base metal salts, their oxides and the metal nanoparticles derived therefrom, and 3) it contributes as a reducing agent via carbothermal reduction for the conversion of the metal oxide nanoparticles into the metal nanoparticles. Finally, the base metal nanoparticles capable of forming metastable metal carbides catalytically convert the carbonaceous support into a mesoporous graphitic carbon material.
Tree height–diameter allometry across the United States
Authors: Hulshof Catherine M. , Swenson Nathan G. , Weiser Michael D. 
Published: February 2015

AbstractThe relationship between tree height and diameter is fundamental in determining community and ecosystem structure as well as estimates of biomass and carbon storage. Yet our understanding of how tree allometry relates to climate and whole organismal function is limited. We used the Forest Inventory and Analysis National Program database to determine height–diameter allometries of 2,976,937 individuals of 293 tree species across the United States. The shape of the allometric relationship was determined by comparing linear and nonlinear functional forms. Mixed‐effects models were used to test for allometric differences due to climate and floristic (between angiosperms and gymnosperms) and functional groups (leaf habit and shade tolerance). Tree allometry significantly differed across the United States largely because of climate. Temperature, and to some extent precipitation, in part explained tree allometric variation. The magnitude of allometric variation due to climate, however, had a phylogenetic signal. Specifically, angiosperm allometry was more sensitive to differences in temperature compared to gymnosperms. Most notably, angiosperm height was more negatively influenced by increasing temperature variability, whereas gymnosperm height was negatively influenced by decreasing precipitation and increasing altitude. There was little evidence to suggest that shade tolerance influenced tree allometry except for very shade‐intolerant trees which were taller for any given diameter. Tree allometry is plastic rather than fixed and scaling parameters vary around predicted central tendencies. This allometric variation provides insight into life‐history strategies, phylogenetic history, and environmental limitations at biogeographical scales.
Analysis of Nitric Oxide from Chemical Donors Using CMOS Platinum Microelectrodes
Authors: Feeny Rachel M. , Wydallis John B. , Chen Tom , Tobet Stuart , Reynolds Melissa M. , Henry Charles S. 
Published: February 2015

AbstractElectrochemical detection of NO generated from chemical donors is reported. Because NO is an important biological messenger, many donor sources and detection methods have been developed. Few reports have characterized NO donors using electrochemistry despite electrochemical techniques being sensitive and selective. Here, a CMOS platinum microelectrode array is interfaced with a microfluidic device for the electrochemical analysis of NO from (Z)‐1‐[N‐(2‐aminoethyl)‐N‐(2‐ammonioethyl)amino]diazen‐1‐ium‐1,2‐diolate (DETA/NO). The donor parent amine fouls the electrode, resulting in substantial signal loss, but an electrochemical cleaning method was developed that substantially reduces fouling and allows detection of NO between 90 nM and 1 µM.
Screen Printed Alizarin‐Based Carbon Electrodes: Monitoring pH in Unbuffered Media
Authors: Dai Chencheng , Song Peng , Wadhawan Jay D. , Fisher Adrian C. , Lawrence Nathan S. 
Published: February 2015

AbstractAn alizarin based voltammetric pH sensor is introduced. This device is fabricated by screen printing the alizarin, which is a pH‐sensitive redox compound, mixed with carbon ink onto the carbon aluminum (aluminum foil coated with carbon paste). This electrode shows a Nernst response to both the buffered and unbuffered media, with a potential shift by 55.8 mV/pH unit and a working range up to pH 10. This approach suggests a disposable, reproducible, low‐cost method for pH sensing with the possibility of miniaturization. A further study of this type of sensor coated with nafion reveals a possible method to expand the working range and improve the stability.
Hydraulic properties of concentrated flow of a bank gully in the dry‐hot valley region of southwest China
Authors: Su Zhengan , Xiong Donghong , Dong Yifan , Zhang Baojun , Zhang Su , Zheng Xueyong , Yang Dan , Zhang Jianhui , Fan Jianrong , Fang Haidong 
Published: February 2015

AbstractTo quantify spatiotemporal variation in hydraulic properties of bank gully concentrated flow, a series of scour experiments were run under water discharge rates ranging from 30 to 120 l min−1. Concentrated flows were found to be turbulent and supercritical in the upstream catchment area and downstream gully beds. As discharge increased, values of the soil erosion rate, Reynolds number (Re), shear stress, stream power, and flow energy consumption (ΔE) increased while values of the Froude number (Fr) and the Darcy–Weisbach friction factor (resistance f ) did not. With the exception of gully headcut collapse under discharge rates of 60, 90, and 120 l min−1, a declining power function trend (P < 0.05) in the soil erosion rate developed in the upstream catchment area, headcuts, and downstream gully beds. However, increasing trends were observed in temporal variations of hydraulic properties for downstream gully beds and the upstream catchment area. Despite significant differences in temporal variation between the soil erosion rate and hydraulic property values, relative steady state conditions of the soil erosion rate and ΔE were attained following an initial period of adjustment in the upstream catchment area, headcuts, and downstream gully beds under different discharge rates. A logarithmic growth of flow energy consumption per unit soil loss (ΔEu) was observed in bank gullies and the upstream catchment area as the experiment progressed, further illustrating the actual reason behind the discrepancy in temporal variation between soil erosion rates and ΔE. Results demonstrate that ΔE can be used to estimate headcut erosion soil loss, but further quantitative studies are required to quantify coupling effects between hydraulic properties and vertical variation in soil mechanical properties on temporal variation for bank gully soil erosion rates. Copyright © 2015 John Wiley & Sons, Ltd.
The influence of leaf litter diversity and soil fauna on initial soil erosion in subtropical forests
Authors: Seitz Steffen , Goebes Philipp , Zumstein Pascale , Assmann Thorsten , Kühn Peter , Niklaus Pascal A. , Schuldt Andreas , Scholten Thomas 
Published: February 2015

AbstractAlthough the protective role of leaf litter cover against soil erosion is known for a long time, little research has been conducted on the processes involved. Moreover, the impact of soil meso‐ and macrofauna within the litter layer on erosion control is not clear. To investigate how leaf litter cover and diversity as well as meso‐ and macrofauna influence sediment discharge in subtropical forest ecosystems, a field experiment has been carried out in Southeast China. A full‐factorial random design with 96 micro‐scale runoff plots and 7 domestic leaf species was established and erosion was triggered by a rainfall simulator. Our results demonstrate that leaf litter cover protects soil from erosion (−82 % sediment discharge on leaf covered plots) by rainfall and this protection is removed as litter decomposes. The protective effect is influenced by the presence or absence of soil meso‐ and macrofauna. Fauna presence increases soil erosion rates significantly by 58 %, while leaf species diversity shows a non‐significant negative trend. We assume that the faunal effect arises from arthropods slackening and processing the soil surface as well as fragmenting and decomposing the protecting leaf litter covers. Even though the diversity level did not show a significant influence, single leaf species in monocultures show rather different impacts on sediment discharge and thus, erosion control. In our experiment, runoff plots with leaf litter fromMachilus thunbergiishowed the highest sediment discharge (68.0 g m−2) whereas plots withCyclobalanopsis glaucashowed the smallest rates (7.9 g m−2). Copyright © 2015 John Wiley & Sons, Ltd.
Cognitive functioning throughout the treatment history of clinical late‐life depression
Authors: Dzierzewski Joseph M. , Potter Guy G. , Jones Richard N. , Rostant Ola S. , Ayotte Brian , Yang Frances M. , C. Sachs Bonnie , Feldman Betsy J. , Steffens David C. 
Published: February 2015

ObjectivePrevious investigations into the relationship between late‐life depressive symptoms and cognitive functioning have resulted in mixed findings concerning whether or not depressive symptoms and cognitive functioning are related. The mixed reports may be due in part to differences in clinical and nonclinical samples and to inadequate consideration of the dynamic nature (i.e., fluctuating course) of depressive symptoms and cognitive functioning in older adults. The current study examined the chronic, acute, and longitudinal relationships between depressive symptoms and cognitive functioning in older adults in an ongoing treatment study of major depressive disorder (MDD).MethodsThe neurocognitive outcomes of depression in the elderly study operates in a naturalistic treatment milieu using a pharmacological treatment algorithm and regular psychiatric assessment. Four hundred and fifty‐three older adults [mean age 70 years, standard deviation (SD) = 7.2] meeting criteria for MDD at study enrollment received annual neuropsychological testing and depressive symptom monitoring for an average of 8.5 years (SD = 4.5).ResultsHierarchical linear modeling revealed that higher age, lower education, and higher average/chronic levels of depressive symptoms were related to lower cognitive functioning. Additionally, results revealed that when an individual's depressive symptoms are higher than is typical for a specific individual, general cognitive function was worse than average. There was no evidence of lagged/longitudinal relationships between depressive symptoms and cognitive functioning in older adults in treatment for MDD.ConclusionsCognitive functioning and depressive symptoms are concurrently associated in older adults with MDD, highlighting the potential importance for stabilizing mood symptoms as a means to manage cognitive deficits in late‐life depression. Copyright © 2015 John Wiley & Sons, Ltd.
Impact of aging on frontostriatal reward processing
Authors: Vink Matthijs , Kleerekooper Iris , van den Wildenberg Wery P. M. , Kahn Rene S. 
Published: February 2015

AbstractHealthy aging is associated with a progressive decline across a range of cognitive functions. An important factor underlying this decline may be the age‐related impairment in stimulus–reward processing. Several studies have investigated age‐related effects, but compared young versus old subjects. This is the first study to investigate the effect of aging on brain activation during reward processing within a continuous segment of the adult life span. We scanned 49 healthy adults aged 40–70 years, using functional MRI. We adopted a simple reward task, which allowed separate evaluation of neural responses to reward anticipation and receipt. The effect of reward on performance accuracy and speed was not related to age, indicating that all subjects could perform the task correctly. We identified a whole‐brain significant age‐related decline of ventral striatum activation during reward anticipation as compared to neutral anticipation. Importantly, the specificity of this finding was underscored by the observation that there was no general decline in activation during anticipation. Activation in the ventral striatum increased with age during reward receipt as compared to receiving neutral outcome. Finally, activation in the ventromedial prefrontal cortex during outcome was not affected by age. Our data demonstrate that the typical shift in striatal activation from reward receipt to reward anticipation in young adults disappears with healthy aging. These changes are consistent the well‐ocumented age‐related decline of striatal dopamine availability, and may provide a stepping stone for further research of age‐related neurodegenerative diseases. Hum Brain Mapp 36:2305–2317, 2015. © 2015 Wiley Periodicals, Inc.
Enhanced neural responsiveness to reward associated with obesity in the absence of food‐related stimuli
Authors: Opel Nils , Redlich Ronny , Grotegerd Dominik , Dohm Katharina , Haupenthal Cordula , Heindel Walter , Kugel Harald , Arolt Volker , Dannlowski Udo 
Published: February 2015

AbstractBackgroundObesity has been characterized by alterations in brain structure and function associated with emotion processing and regulation. Particularly, aberrations in food‐related reward processing have been frequently demonstrated in obese subjects. However, it remains unclear whether reward‐associated functional aberrations in obesity are specific for food‐related stimuli or represent a general deficit in reward processing, extending to other stimulus domains. Given the crucial role of rewarding effects in the development of obesity and the ongoing discussion on overlapping neurobiological traits of obesity and psychiatric disorders such as depression and substance‐related disorders, this study aimed to investigate the possibility of altered reward processing in obese subjects to occur in the absence of food‐related stimuli during a monetary reward condition.MethodsTwenty‐nine healthy obese subjects (body mass index >30) and 29 healthy, age‐, and sex‐matched control subjects of normal weight underwent functional MRI during a frequently used card guessing paradigm. A Group × Condition (win vs. loss) ANOVA was conducted to investigate differences between obese and normal‐weight subjects.ResultsWe found significant Group × Condition interaction effects in brain areas involved in emotion regulation and reward processing including the insula, the striatum, and the orbitofrontal cortex (OFC). This interaction was predominantly driven by a significant increase in blood oxygenation level dependent (BOLD) response in obese individuals while experiencing reward.ConclusionsEnhanced neural activation in obesity during reward processing seems to be apparent even in the absence of food‐related stimuli and, thus, might point to generalized dysfunctions in reward‐related brain circuits in obese individuals. Hum Brain Mapp 36:2330–2337, 2015. © 2015 Wiley Periodicals, Inc.
Influence of spatial and temporal flow variability on solute transport in catchments
Authors: Selroos Jan‐Olof , Destouni Georgia 
Published: February 2015

AbstractThis study quantifies the separate and combined effects of spatial and temporal variability for waterborne solute transport through catchments. The questions addressed regard whether, when and why the different types of variability may dominate catchment‐scale transport. We utilize a versatile numerical solute transport code with a particle‐based Monte Carlo time‐domain random walk method to simulate waterborne transport through a generic catchment. Simulations are concretized and exemplified using data on spatiotemporal flow–transport variability from direct stream discharge observations and independently calculated advective solute travel time distributions for catchments within the water management district Northern Baltic Proper in Mid‐Eastern Sweden. A main conclusion is that the projections of catchment mass loading based on spatial variability alone are robust estimates of long‐term average solute transport development. This is especially true when annually aggregated mass load rather than finer temporal resolution of mass flux is considered. Temporal variability yields short‐term fluctuations around the long‐term average solute breakthrough development, and earlier or later arrival than the latter, depending on the timing and duration of solute input relative to the temporal flow variability. The exact temporal characteristics of future solute breakthrough are thus fundamentally uncertain, but their statistical expectation may be well quantified by accounting only for spatial variability. Copyright © 2015 John Wiley & Sons, Ltd.
Mechanistic Enzymology of the Radical SAM Enzyme DesII
Authors: Ruszczycky Mark W. , Liu Hung‐wen 
Published: February 2015

AbstractDesII is a member of the radical SAM family of enzymes that catalyzes radical‐mediated transformations of TDP‐4‐amino‐4,6‐didexoy‐D‐glucose, as well as other sugar nucleotide diphosphates. Like nearly all radical SAM enzymes, the reactions begin with the reductive homolysis of SAM to produce a 5′‐deoxyadenosyl radical, which is followed by regiospecific hydrogen atom abstraction from the substrate. What happens next, however, depends on the nature of the substrate radical so produced. In the case of the biosynthetically relevant substrate, a radical‐mediated deamination ensues; however, when this amino group is replaced with a hydroxyl, one instead observes dehydrogenation. The factors that govern the fate of the initially generated substrate radical, as well as the mechanistic details underlying these transformations, have been a key focus of research into the chemistry of DesII. This review will discuss recent discoveries pertaining to the enzymology of DesII, how it may relate to understanding other radical‐mediated lyases and dehydrogenases, and the working hypotheses currently being investigated regarding the mechanism of DesII catalysis.
The Unpredictability of Research Directions and the Synergy between Theory and Experiment in Physical‐Organic Chemistry
Authors: Borden Weston Thatcher 
Published: February 2015

AbstractResearch projects in physical‐organic chemistry can go in unpredictable directions. One such project, described herein, began with the discovery of a large, imaginary, calculated vibrational frequency and soon led to the prediction that cyclobutanetetraone (CO)4 had a triplet ground state. Molecular orbital (MO) theory provided the understanding of why (CO)4 was calculated to have a planar triplet ground state and why, in contrast, (SiO)4 was calculated to have a tetrahedral singlet ground state. Qualitative MO theory, as well as calculations, also predicted that (CO)3, (CO)5, and (CO)6 should all be found to have singlet ground states. Testing experimentally these predictions about (CO)n molecules, n=3–6, led to a very fruitful collaboration with Dr. Xuebin Wang, who obtained the negative ion photoelectron (NIPE) spectra of the radical anions of these four molecules and also of (CS)4. Assignments of the signals in these five NIPE spectra required computing the vibrational progressions in them. The necessary acquisition of the ability to simulate the signals in NIPE spectra resulted in the successful analysis of the very complex spectrum of meta‐benzoquinone (MBQ) radical anion, which Dr. Wang had already obtained and published. Analysis of this spectrum confirmed the prediction, made more than 20 years previously, that the ordering of the two lowest singlet states in MBQ was reversed from that in meta‐benzoquinodimethane (MBQDM). The research described herein illustrates not only the unpredictability of where some research projects will eventually lead, but also the synergy between calculations and experiments in physical‐organic chemistry.
Functional Peptide Monolayers at Interfaces
Authors: Baruch Leshem Avigail , Zarzhitsky Shlomo , Rapaport Hanna 
Published: February 2015

AbstractAmphiphilic peptides can be designed to form ordered supramolecular structures at hydrophilic‐hydrophobic interfaces. These systems rely on the ability of peptides to fold into certain secondary structures at interfaces. This review focuses on the design of amphiphilic β‐sheet peptide assemblies in monolayers at interfaces, and their relevance to inducing mineralization and interactions with specific ions. In addition, the review discusses recent studies demonstrating the applicability of designed amphiphilic β‐sheet peptides to detection of specific small molecules and to elucidating intermolecular interactions relevant to drug delivery and enzyme catalysis systems.