bluuebunny/crossref_metadata_2025_split huggingface dataset:
Few‐Layer Nanosheets of n‐Type SnSe2
Authors: Saha Sujoy , Banik Ananya , Biswas Kanishka 
Published: September 2016

AbstractLayered p‐block metal chalcogenides are renowned for thermoelectric energy conversion due to their low thermal conductivity caused by bonding asymmetry and anharmonicity. Recently, single crystalline layered SnSe has created sensation in thermoelectrics due to its ultralow thermal conductivity and high thermoelectric figure of merit. Tin diselenide (SnSe2), an additional layered compound belonging to the Sn‐Se phase diagram, possesses a CdI2‐type structure. However, synthesis of pure‐phase bulk SnSe2 by a conventional solid‐state route is still remains challenging. A simple solution‐based low‐temperature synthesis is presented of ultrathin (3–5 nm) few layers (4–6 layers) nanosheets of Cl‐doped SnSe2, which possess n‐type carrier concentration of 2×1018 cm−3 with carrier mobility of about 30 cm2 V−1 s−1 at room temperature. SnSe2 has a band gap of about 1.6 eV and semiconducting electronic transport in the 300–630 K range. An ultralow thermal conductivity of about 0.67 Wm−1 K−1 was achieved at room temperature in a hot‐pressed dense pellet of Cl‐doped SnSe2 nanosheets due to the anisotropic layered structure, which gives rise to effective phonon scattering.
In Situ Growth of Co3O4 Nanoparticles on Interconnected Nitrogen‐Doped Graphene Nanoribbons as Efficient Oxygen Reduction Reaction Catalyst
Authors: Lu Hengyi , Yan Jiajie , Zhang Youfang , Huang Yunpeng , Gao Wei , Fan Wei , Liu Tianxi 
Published: September 2016

AbstractA simple, low cost and nontoxic preparation method to obtain high performance oxygen reduction reaction (ORR) catalysts is of great significance in fuel cell fields. Herein, graphene nanoribbons (GNRs) with numerous graphitic edges are chosen as supporting material to hybridize with nitrogen atoms and cobalt oxide (Co3O4) through a simple one‐step hydrothermal reaction. With a high edge‐to‐plane ratio, the GNR sheets could increase the accessibility of N‐atom doping into the graphene edges to form active ORR sites, and be also interconnected with each other to form a conductive network, thus facilitating the fast electron transfer. The intimate contacts between Co3O4 nanoparticles and nitrogen‐doped GNRs (N‐GNRs) along with the porous structure impart the N‐GNR/Co3O4 hybrid with excellent ORR performance, which leads to a comparable onset‐potential to commercial Pt/C catalyst but larger current density, better long‐term stability and superior tolerance to crossover effects.
Collisions of FeO+ with H2 and He in a Cryogenic Ion Trap
Authors: Gerlich Dieter , Jašík Juraj , Andris Erik , Navrátil Rafael , Roithová Jana 
Published: September 2016

AbstractThe nominal temperature range of cryogenic radio‐frequency ion traps has recently been extended down to T=2.3 K. Whereas in situ He tagging of mass‐selected ions embedded in dense helium buffer gas is becoming common for recording IR spectra through photofragmentation of small and large ions, much less activity is devoted to the field of cold chemistry, which in this contribution means the two orders of magnitude extending from 300 to below 3 K. The importance of this temperature range for understanding the dynamics of bi‐ and termolecular reactions is illustrated with new results for the time‐honored reaction of FeO+ with H2 obtained with the cryogenic ion trap ISORI in Prague. The rate coefficient for forming Fe++H2O increases steeply with decreasing temperature. In addition more product channels open up, such as the stabilized reaction‐intermediate complexes H2FeO+ and Hen–FeO+ formed by ternary association with He. For the FeOH++H channel only a minor signal is observed. The rate coefficients provide deep insight into lifetimes, bottlenecks, and barriers impeding almost completely the exothermic, but spin‐forbidden, reaction at room temperature. For some of the He‐tagged ions, IR predissociation spectra are recorded. A breakthrough is obtaining the first spectrum of [(H2)FeO]+, synthesized and tagged in situ with He. These results pave the way to study the structures of reaction intermediates stabilized in the gas phase by means of collisions with helium.
Impact of exercise and a complex environment on hippocampal dendritic morphology,Bdnfgene expression, andDNAmethylation in male rat pups neonatally exposed to alcohol
Authors: Boschen K. E. , McKeown S. E. , Roth T. L. , Klintsova A. Y. 
Published: September 2016

ABSTRACTAlcohol exposurein uterocan result in Fetal Alcohol Spectrums Disorders (FASD). Measures of hippocampal neuroplasticity, including long‐term potentiation, synaptic and dendritic organization, and adult neurogenesis, are consistently disrupted in rodent models of FASD. The current study investigated whether third trimester‐equivalent binge‐like alcohol exposure (AE) [postnatal days (PD) 4–9] affects dendritic morphology of immature dentate gyrus granule cells, and brain‐derived neurotrophic factor (Bdnf) gene expression and DNA methylation in hippocampal tissue in adult male rats. To understand immediate impact of alcohol, DNA methylation was measured in the PD10 hippocampus. In addition, two behavioral interventions, wheel running (WR) and environmental complexity (EC), were utilized as rehabilitative therapies for alcohol‐induced deficits. AE significantly decreased dendritic complexity of the immature neurons, demonstrating the long‐lasting impact of neonatal alcohol exposure on dendritic morphology of immature neurons in the hippocampus. Both housing conditions robustly enhanced dendritic complexity in the AE animals. WhileBdnfexon I DNA methylation was lower in the AE and sham‐intubated animals compared with suckle controls on PD10, alterations toBdnfDNA methylation and gene expression levels were not present at PD72. In control animals, exercise, but not exercise followed by housing in EC, resulted in higher levels of hippocampalBdnfgene expression and lower DNA methylation. These studies demonstrate the long‐lasting negative impact of developmental alcohol exposure on hippocampal dendritic morphology and support the implementation of exercise and complex environments as therapeutic interventions for individuals with FASD. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 708–725, 2017
Interspecific variation in persistence of buried weed seeds follows trade‐offs among physiological, chemical, and physical seed defenses
Authors: Davis Adam S. , Fu Xianhui , Schutte Brian J. , Berhow Mark A. , Dalling James W. 
Published: September 2016

Abstract

Soil seedbanks drive infestations of annual weeds, yet weed management focuses largely on seedling mortality. As weed seedbanks increasingly become reservoirs of herbicide resistance, species‐specific seedbank management approaches will be essential to weed control. However, the development of seedbank management strategies can only develop from an understanding of how seed traits affect persistence.

We quantified interspecific trade‐offs among physiological, chemical, and physical traits of weed seeds and their persistence in the soil seedbank in a common garden study. Seeds of 11 annual weed species were buried in Savoy, IL, from 2007 through 2012. Seedling recruitment was measured weekly and seed viability measured annually. Seed physiological (dormancy), chemical (phenolic compound diversity and concentration; invertebrate toxicity), and physical traits (seed coat mass, thickness, and rupture resistance) were measured.

Seed half‐life in the soil (t0.5) showed strong interspecific variation (F10,30 = 15, p < .0001), ranging from 0.25 years (Bassia scoparia) to 2.22 years (Abutilon theophrasti). Modeling covariances among seed traits and seedbank persistence quantified support for two putative defense syndromes (physiological–chemical and physical–chemical) and highlighted the central role of seed dormancy in controlling seed persistence.

A quantitative comparison between our results and other published work indicated that weed seed dormancy and seedbank persistence are linked across diverse environments and agroecosystems. Moreover, among seedbank‐forming early successional plant species, relative investment in chemical and physical seed defense varies with seedbank persistence.

Synthesis and applications. Strong covariance among weed seed traits and persistence in the soil seedbank indicates potential for seedbank management practices tailored to specific weed species. In particular, species with high t0.5 values tend to invest less in chemical defenses. This makes them highly vulnerable to physical harvest weed seed control strategies, with small amounts of damage resulting in their full decay.
Dynamics of non‐structural carbohydrates in terrestrial plants: a global synthesis
Authors: Martínez‐Vilalta Jordi , Sala Anna , Asensio Dolores , Galiano Lucía , Hoch Günter , Palacio Sara , Piper Frida I. , Lloret Francisco 
Published: September 2016

AbstractPlants store large amounts of non‐structural carbohydrates (NSC). While multiple functions ofNSChave long been recognized, the interpretation ofNSCseasonal dynamics is often based on the idea that storedNSCis a reservoir of carbon that fluctuates depending on the balance between supply via photosynthesis and demand for growth and respiration (the source–sink dynamics concept). Consequently, relatively highNSCconcentrations in some plants have been interpreted to reflect excess supply relative to demand. An alternative view, however, is thatNSCaccumulation reflects the relatively highNSClevels required for plant survival; an important issue that remains highly controversial. Here, we assembled a new global database to examine broad patterns of seasonalNSCvariation across organs (leaves, stems, and belowground), plant functional types (coniferous, drought‐deciduous angiosperms, winter deciduous angiosperms, evergreen angiosperms, and herbaceous) and biomes (boreal, temperate, Mediterranean, and tropical). We compiled data from 121 studies, including seasonal measurements for 177 species under natural conditions. Our results showed that, on average,NSCaccount for ~10% of dry plant biomass and are highest in leaves and lowest in stems, whereas belowground organs show intermediate concentrations. TotalNSC, starch, and soluble sugars (SS) varied seasonally, with a strong depletion of starch during the growing season and a general increase during winter months, particularly in boreal and temperate biomes. Across functional types,NSCconcentrations were highest and most variable in herbaceous species and in conifer needles. Conifers showed the lowest stem and belowgroundNSCconcentrations. MinimumNSCvalues were relatively high (46% of seasonal maximums on average for totalNSC) and, in contrast to average values, were similar among biomes and functional types. Overall, although starch depletion was relatively common, seasonal depletion of totalNSCorSSwas rare. These results are consistent with a dual view ofNSCfunction: whereas starch acts mostly as a reservoir for future use, soluble sugars perform immediate functions (e.g., osmoregulation) and are kept above some critical threshold. If confirmed, this dual function ofNSCwill have important implications for the way we understand and model plant carbon allocation and survival under stress.
Measuring Mechanical Properties during the Electrochemical Lithiation of Silicon
Authors: Epler Eike , Roddatis Vladimir V. , Volkert Cynthia A. 
Published: September 2016

AbstractIn situ nanoindentation is used to measure the modulus and hardness of amorphous LixSi during its formation by electrochemical lithiation of (111) silicon surfaces. Due to the large volume changes experienced during lithiation, accurate knowledge of an electrode′s mechanical properties is essential for predicting reliability and developing design guidelines for battery electrodes. We observe a clear decrease in modulus and hardness during lithiation. By accounting for the growing thickness of the amorphous layer, we obtain reliable in operando values for the modulus (45 GPa) and hardness (1 GPa) of the amorphous LixSi, which are in reasonable agreement with literature values obtained under less well‐defined electrochemical conditions. Furthermore, a small increase in modulus just prior to amorphization and the formation of amorphous islands at the early stages lend credence to the idea of the formation of precursor defects in the crystalline silicon prior to amorphization.
Zinc Oxide–Titania Heterojunction‐based Solid Nanospheres as Photoanodes for Electron‐Trapping in Dye‐Sensitized Solar Cells
Authors: Shejale Kiran P. , Laishram Devika , Gupta Ritu , Sharma Rakesh K. 
Published: September 2016

AbstractAgile nanostructure architectures and smart combinations of semiconducting metal oxide materials are key features of high‐performing dye‐sensitized solar cells (DSSCs). Herein, we synthesize mesoporous solid nanospheres of ZnO–TiO2 with type‐II heterojunction and use these as an efficient photoanode material for excellent photoconversion. These polydisperse aggregates doped with 1 %, 5 %, and 10 % of ZnO exhibit improved solar cell performance with respect to pristine TiO2 under AM 1.5 G. The 1 % ZnO doped TiO2 nanosphere possess high specific surface area (84.23 m2 g−1) as a photoanode and shows high photoconversion efficiency of about 8.07 % with ca. 18 % improvement in the photocurrent density (Jsc) compare to TiO2 nanosphere. The improved solar cell performance (Δη=40 %) of ZnO decorated TiO2 nanospheres is ascribed to type‐II heterojunction of ZnO–TiO2, that reduces the electron recombination and synergistically enhances the electron mobility and charge collection capability.
Geomorphic response of the Jingjiang Reach to the Three Gorges Project operation
Authors: Xia Junqiang , Deng Shanshan , Zhou Meirong , Lu Jinyou , Xu Quanxi 
Published: September 2016

AbstractUpstream damming often causes significant downstream geomorphic adjustments. Remarkable channel changes have occurred in the Jingjiang Reach of the Middle Yangtze River, since the onset of the Three Gorges Project (TGP). Therefore, it is important to investigate the variations in different fluvial variables, for better understanding of the channel evolution characteristics as an example of the Jingjiang Reach. Recent geomorphic adjustments in the study reach have been investigated quantitatively, including variations in sediment rating curve, fluvial erosion intensity, channel deformation volume and bankfull channel geometry. These fluvial variables adjusted in varying degrees in response to the altered flow and sediment regime caused by the TGP operation. A focus of this study has been especially on variation in the bankfull channel geometry. Calculated bankfull dimensions at section‐ and reach‐scale indicate that: (i) there were significant bank‐erosion processes in local regions without bank‐protection engineering, with empirical relations being developed to reproduce the variation in bankfull widths at four typical sections; (ii) the variation in the reach‐scale channel geometry occurred mainly in the component of bankfull depth, owing to the construction of large‐scale bank‐revetment works, with the depth increasing from 13.7 m in 2002 to 15.0 m in 2014, and with an increase in the corresponding bankfull area of about 11%; and (iii) the reach‐scale bankfull channel dimensions responded to the previous 5‐year average fluvial erosion intensity during flood seasons at Zhicheng, with higher correlations for the depth and area being obtained when calibrated by the measurements in 2002–2012. Furthermore, these relations developed for the section‐ and reach‐scale bankfull channel geometry were also verified by the observed data in 2013–2014, with encouraging results being obtained. Copyright © 2016 John Wiley & Sons, Ltd.
Effects of carbon dioxide on juveniles of the freshwater mussel (Lampsilis siliquoidea [Unionidae])
Authors: Waller Diane L. , Bartsch Michelle R. , Fredricks Kim T. , Bartsch Lynn A. , Schleis Susan M. , Lee Sheldon H. 
Published: September 2016

Abstract

Carbon dioxide (CO2) has shown promise as a tool to control movements of invasive Asian carp, but its effects on native freshwater biota have not been well studied. The authors evaluated lethal and sublethal responses of juvenile fatmucket (Lampsilis siliquoidea) mussels to CO2 at levels (43–269 mg/L, mean concentration) that bracket concentrations effective for deterring carp movement. The 28-d lethal concentration to 50% of the mussels was 87.0 mg/L (95% confidence interval [CI] 78.4–95.9) and at 16-d postexposure, 76.0 mg/L (95% CI 62.9–90.3). A proportional hazards regression model predicted that juveniles could not survive CO2 concentrations &gt;160 mg/L for more than 2 wk or &gt;100 mg/L CO2 for more than 30 d. Mean shell growth was significantly lower for mussels that survived CO2 treatments. Growth during the postexposure period did not differ among treatments, indicating recovery of the mussels. Also, CO2 caused shell pitting and erosion. Behavioral effects of CO2 included movement of mussels to the substrate surface and narcotization at the highest concentrations. Mussels in the 110 mg/L mean CO2 treatment had the most movements in the first 3 d of exposure. If CO2 is infused continuously as a fish deterrent, concentrations &lt;76 mg/L are recommended to prevent juvenile mussel mortality and shell damage. Mussels may survive and recover from brief exposure to higher concentrations. Environ Toxicol Chem 2017;36:671–681. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
Risk assessment from exposure to arsenic, antimony, and selenium in urban gardens (Madrid, Spain)
Authors: De Miguel Eduardo , Izquierdo Miguel , Gómez Amaia , Mingot Juan , Barrio-Parra Fernando 
Published: September 2016

Abstract

The authors discuss the geochemical behavior of arsenic (As), antimony (Sb), and selenium (Se) in urban gardens and the human health implications associated with urban agriculture. A total of 42 samples from 7 urban gardens in Madrid, Spain, were collected from the top 20 cm of soil. Concentrations of As, Sb, and Se and the main soil properties (i.e., total iron, pH, texture, calcium carbonate, and organic matter) were determined. A significant correlation was found between As and Sb and calcium carbonate, indicating the possibility of surface adsorption or ligand exchange with the carbonate group. Also, Sb seemed to form stable chelates with soil organic matter. On the other hand, Se showed a significant association with clay and iron content. The concentration of Sb in soil exceeded the recommended value for agricultural use in 70% of the urban gardens. A human health risk assessment resulted in acceptable levels of both noncarcinogenic and carcinogenic risks (although with elevated values of the latter), with As as the main risk driver and soil and food ingestion as the main exposure pathways. The numerical results of the risk assessment should be interpreted with caution given the considerable uncertainties in some exposure variables and the lack of quantitative values for the suspected carcinogenicity of Sb and Se. Environ Toxicol Chem 2017;36:544–550. © 2016 SETAC
Sucrose modifies growth and physiology in axenically grown Myriophyllum spicatum with potential effects on the response to pollutants
Authors: Nuttens Andréïna , Gross Elisabeth Maria 
Published: September 2016

Abstract

Sucrose as a carbon source in axenic tests affects plant growth and physiology. The high sucrose concentration in Organisation for Economic Co-operation and Development (OECD) guideline 238 for the submerged growing aquatic plant Myriophyllum spicatum might modify pollutant effects, thus impairing environmental risk assessment. In a factorial design experiment with axenic M. spicatum exposed to 3 sucrose concentrations (no, low, and high) with or without cadmium, growth, dry matter content, content in pigments or phenolic compounds, and elemental stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) were measured. The results show that sucrose is crucial for growth but can be used at lower concentrations than currently considered. Sucrose-treated plants had higher dry matter content and C content but lower contents of chlorophyll and N. Cadmium affected the content in chlorophyll, phenolic compounds, and elemental stoichiometry. Interactive effects were observed on length growth, C and N content, and the C:N and N:P molar ratios. Remarkably, cadmium led to increased shoot length at low, but not at high, sucrose concentration. This contrasting effect might result from differences in osmotic potential caused by sucrose. Overall, the results suggest a strong effect of sucrose concentration on the growth and physiology of M. spicatum and modifications of the response to cadmium. Further studies should establish the lowest sucrose level needed to account for realistic environmental risk assessment based on the axenic OECD 238. Environ Toxicol Chem 2017;36:969–975. © 2016 SETAC.
General and histological indicators of health in wild fishes from a biological mercury hotspot in northeastern North America
Authors: Graves Stephanie D. , Kidd Karen A. , Houlahan Jeff E. , Munkittrick Kelly R. 
Published: September 2016

Abstract

Kejimkujik National Park and National Historic Site, Nova Scotia, Canada, is considered a biological mercury (Hg) hotspot because the tissues of yellow perch (Perca flavescens) and common loons (Gavia immer) inhabiting the lakes frequently exceed so-called safe levels of Hg. In the present study, the relationships between Hg and overall health of males and females of 3 forage fish species (brown bullhead Ameirus nebulosus, banded killifish Fundulus diaphanus, and golden shiner Notemigonus crysoleucas; n = 6–18/sex/lake) in 6 lakes at the park were assessed using condition factor, liversomatic index (LSI), and macrophage aggregates (MAs; indicators of tissue damage). Mean muscle total Hg (THg) concentrations of brown bullhead, banded killifish, and golden shiner across lakes were 0.32 μg/g, 0.27 μg/g, and 0.34 μg/g, respectively. Condition was negatively related to muscle THg in golden shiner and banded killifish, LSI was not related to THg in any species, and all species showed evidence of increasing MA prevalence (counts and area) with increasing THg concentrations. The MAs were most prevalent in spleen tissues of golden shiner, with mean percentage cover ranging from 0.36% to 5.59% across lakes. In addition, the area of MAs appeared to be better predicted by THg concentration than was the number of MAs in the same tissue. These findings suggest that Hg is affecting the health of wild fishes in Kejimkujik National Park and National Historic Site and that other populations with similar or higher concentrations of this metal may also be at risk. Environ Toxicol Chem 2017;36:976–987. © 2016 SETAC