bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theory and Simulations for the Electron‐Transfer/Ion‐Transfer Mode of Scanning Electrochemical Microscopy in the Presence or Absence of Homogenous Kinetics
Authors: Oleinick Alexander , Yu Yun , Svir Irina , Mirkin Michael V. , Amatore Christian 
Published: October 2016

AbstractThe electron‐transfer/ion‐transfer (ET/IT) mode of scanning electrochemical microscopy (SECM) was developed recently and applied to studies of heterogeneous reactions at the substrate surface. The charged products or intermediates are detected by measuring the ion‐transfer current of the species across the liquid/liquid interface supported at the tip of a nanopipette. In this article, we develop the theory for this technique and explore its potential advantages and limitations. By using the COMSOL Multiphysics package, the approach curves were simulated for three commonly encountered experimental situations, that is, the surface‐generated ionic species is either chemically stable or participates in a first‐ or second‐order homogeneous reaction. The simulation results are generalized in the form of analytical approximations derived under limiting conditions.
Iridium‐Catalyzed Asymmetric Hydrogenation of Unfunctionalized Exocyclic C=C Bonds
Authors: Xia Jingzhao , Yang Guoqiang , Zhuge Ruijing , Liu Yangang , Zhang Wanbin 
Published: October 2016

AbstractAn iridium‐catalyzed asymmetric hydrogenation of unfunctionalized exocyclic C=C bonds was performed by using an axially flexible chiral phosphine–oxazoline ligand, providing the desired chiral 1‐benzyl‐2,3‐dihydro‐1H‐indene products with up to 98 % ee (enantiomeric excess). This represents the first general hydrogenation of unfunctionalized exocyclic olefins with high selectivity reported thus far. The additive acetate ion plays an important role in the reaction's high enantioselectivity. The chiral product can be further transformed into key intermediates required for the synthesis of an important insecticide and a drug compound.
Continuous bioproduction of 1,3‐propanediol from biodiesel raw glycerol: Operation with free and immobilized cells of Clostridium butyricum DSM 10702
Authors: Loureiro‐Pinto Marina , Coca Mónica , González‐Benito Gerardo , Lucas Susana , García‐Cubero M. Teresa 
Published: October 2016

AbstractThis work investigates the bioproduction of 1,3‐propanediol (1,3‐PD) from biodiesel derived raw glycerol with free and immobilized cells of Clostridium butyricum DSMZ 10702. The cultures were carried out under continuous conditions in a stirred tank bioreactor with suspended cells and a fluidized‐bed bioreactor with immobilized cells. The microorganisms were immobilized by entrapment in calcium alginate gel beads. The effect of dilution rate and glycerol concentration in the feed on 1,3‐PD production was investigated for both bioreactor configurations. Results showed that 1,3‐PD concentration and glycerol uptake decreased when dilution rate increased. Maximum product concentration was similar in both bioreactors, 24.3 g/L and 20.5 g/L for suspended cells and Ca‐alginate immobilized cells, respectively, for a glycerol feed concentration of 50 g/L and a dilution rate of 0.05 h−1. The higher productivities were observed for a dilution rate of 0.15 h−1 for the suspended culture bioreactor and 0.2 h−1 for the immobilized cell bioreactor. Although maximum productivity was similar in both systems, 2.8 g 1,3‐PD/(L · h), cell immobilization was shown to be more resistant to washout at higher dilution rates.
Heterogeneous cloudlet deployment and user‐cloudlet association toward cost effective fog computing
Authors: Yao Hong , Bai Changmin , Xiong Muzhou , Zeng Deze , Fu Zhangjie 
Published: October 2016

SummaryBoth mobile computing and cloud computing have experienced rapid development in recent years. Although centralized cloud computing exhibits abundant resources for computation‐intensive tasks, the unpredictable and unstable communication latency between the mobile users and the cloud makes it challenging to handle latency‐sensitive mobile computing tasks. To address this issue, fog computing recently was proposed by pushing the cloud computing to the network edge closer to the users. To realize such vision, we can augment existing access points in wireless networks with cloudlet servers for hosting various mobile computing tasks. In this paper, we investigate how to deploy the servers in a cost‐effective manner without violating the predetermined quality of service. In particular, we practically consider that the available cloudlet servers are heterogeneous, ie, with different cost and resource capacities. The problem is formulated into an integer linear programming form, and a low‐complexity heuristic algorithm is invented to address it. Extensive simulation studies validate the efficiency of our algorithm by it performs much close to the optimal solution.
Robust human detection and localization in security applications
Authors: Chowdhury Mozammel , Gao Junbin , Islam Rafiqul 
Published: October 2016

SummaryHuman detection and localization has attracted much attention in security applications because of the increasing demand of safety and security in different environments, including surveillance systems, secure access control, person recognition, border monitoring, preventing criminal acts, intrusion detection, alarm monitoring, and so on. This article proposes a robust approach for human detection and localization by analyzing and matching corresponding facial features extracted from video sequences. The proposed technique captures the video scenes using a stereo system consisting of two cameras: left and right cameras with similar intrinsic parameters. The system first tracks the human by detecting the face area from the video scenes using an efficient fuzzy face detection algorithm. To localize the human position, the depth information is computed from the extracted face images by using a robust stereo matching algorithm. A neural network is used to match the correspondence pixels between the left and the right face images. Experimental evaluation demonstrates the competence and robustness of the proposed method. The low computation time required for the detection and localization of human objects compared with other methods raises its suitability toward its use in real‐time applications. Copyright © 2016 John Wiley & Sons, Ltd.
Brazil's worst mining disaster: Corporations must be compelled to pay the actual environmental costs
Authors: Garcia Letícia Couto , Ribeiro Danilo Bandini , de Oliveira Roque Fabio , Ochoa‐Quintero Jose Manuel , Laurance William F. 
Published: October 2016

AbstractIn November 2015, a large mine‐tailing dam owned by Samarco Corporation collapsed in Brazil, generating a massive wave of toxic mud that spread down the Doce River, killing 20 people and affecting biodiversity across hundreds of kilometers of river, riparian lands, and Atlantic coast. Besides the disaster's serious human and socioeconomic tolls, we estimate the regional loss of environmental services to be ~US$521 million per year. Although our estimate is conservative, it is still six times higher than the fine imposed on Samarco by Brazilian environmental authorities. To reduce such disparities between estimated damages and levied fines, we advocate for an environmental bond policy that considers potential risks and environmental services that could possibly be impacted by irresponsible mining activity. Environmental bonds and insurance are commonly used policy instruments in many countries, but there are no clear environmental bond policies in Brazil. Environmental bonds are likely to be more effective at securing environmental restitution than post‐disaster fines, which generally are inadequate and often unpaid. We estimate that at least 126 mining dams in Brazil are vulnerable to failure in the forthcoming years. Any such event could have severe social‐environmental consequences, underscoring the need for effective disaster‐management strategies for large‐scale mining operations.
Cropping history trumps fallow duration in long‐term soil and vegetation dynamics of shifting cultivation systems
Authors: Wood Sylvia L. R. , Rhemtulla Jeanine M. , Coomes Oliver T. 
Published: October 2016

AbstractIn the study of shifting cultivation systems, fallow duration is seen as the key determinant of vegetation and soil dynamics: long fallows renew soil fertility, biomass, and biodiversity. However, long fallow systems are increasingly replaced around the world with short–medium fallow systems, and awareness is growing of the need to look across multiple (not just single) crop‐fallow cycles to accurately understand observed soil and vegetation patterns. In a study from Peru that builds on 50+ years of field‐level land‐use histories, we found that, over multiple crop–fallow cycles, farmers' cropping practices mattered more than fallow duration for biodiversity and soil fertility. After initial clearing of primary forest, a precipitous decline occurred in tree species richness of fallows (>50%) with gradual but continued loss thereafter (~0.5 species/yr), which resulted in shifts in species composition over time. For soils, the decline in fertility was more gradual with each additional cycle of cropping resulting in lowered soil organic matter, available phosphorus, and exchangeable sodium levels, even in fields with long fallow durations. In the most intensively used sites, soils experienced a 16% decline of soil organic matter over 4+ cycles. In contrast to previous studies, biomass accumulation and carbon stocks were not related to cropping history or to the number and duration of cycles observed. This suggests that biodiversity–soils–biomass dynamics may not necessarily “move together” in these systems. These results point to the importance of the number of crop–fallow cycles over fallow duration in driving soil fertility and vegetation dynamics under shifting cultivation in the Peruvian Amazon. Overtime shifting cultivation may erode soil fertility and biodiversity levels even if long fallows persist. As the decline in soils appears slow, it may be possible to address this effect with the use of amendments, however biodiversity declines and species compositional changes may be much harder to reverse.
On the influence of provenance to soil quality enhanced stress reaction of young beech trees to summer drought
Authors: Buhk Constanze , Kämmer Marcel , Beierkuhnlein Carl , Jentsch Anke , Kreyling Jürgen , Jungkunst Hermann F. 
Published: October 2016

AbstractClimate projections propose that drought stress will become challenging for establishing trees. The magnitude of stress is dependent on tree species, provenance, and most likely also highly influenced by soil quality. European Beech (Fagus sylvatica) is of major ecological and economical importance in Central European forests. The species has an especially wide physiological and ecological amplitude enabling growth under various soil conditions within its distribution area in Central Europe. We studied the effects of extreme drought on beech saplings (second year) of four climatically distinct provenances growing on different soils (sandy loam and loamy sand) in a full factorial pot experiment. Foliar δ13C, δ15N, C, and N as well as above‐ and belowground growth parameters served as measures for stress level and plant growth. Low‐quality soil enhanced the effect of drought compared with qualitatively better soil for the above‐ and belowground growth parameters, but foliar δ13C values revealed that plant stress was still remarkable in loamy soil. For beeches of one provenance, negative sandy soil effects were clearly smaller than for the others, whereas for another provenance drought effects in sandy soil were sometimes fatal. Foliar δ15N was correlated with plant size during the experiment. Plasticity of beech provenances in their reaction to drought versus control conditions varied clearly. Although a general trend of declining growth under control or drought conditions in sandy soil was found compared to loamy soil, the magnitude of the effect of soil quality was highly provenance specific. Provenances seemed to show adaptations not only to drought but also to soil quality. Accordingly, scientists should integrate information about climatic pre‐adaptation and soil quality within the home range of populations for species distribution modeling and foresters should evaluate soil quality and climatic parameters when choosing donor populations for reforestation projects.
Population genetic isolation and limited connectivity in the purple finch (Haemorhous purpureus)
Authors: Macfarlane Colin Bran Alexander , Natola Libby , Brown Mike W. , Burg Theresa M. 
Published: October 2016

AbstractUsing a combination of mitochondrial and z‐linked sequences, microsatellite data, and spatio‐geographic modeling, we examined historical and contemporary factors influencing the population genetic structure of the purple finch (Haemorhous purpureus). Mitochondrial DNA data show the presence of two distinct groups corresponding to the two subspecies, H. p. purpureus and H. p. californicus. The two subspecies likely survived in separate refugia during the last glacial maximum, one on the Pacific Coast and one east of the Rocky Mountains, and now remain distinct lineages with little evidence of gene flow between them. Southwestern British Columbia is a notable exception, as subspecies mixing between central British Columbia and Vancouver Island populations suggests a possible contact zone in this region. Z‐linked data support two mitochondrial groups; however, Coastal Oregon and central British Columbia sites show evidence of mixing. Contemporary population structure based on microsatellite data identified at least six genetic clusters: three H. p. purpureus clusters, two H. p. californicus clusters, and one mixed cluster, which likely resulted from high site fidelity and isolation by distance, combined with sexual selection on morphological characters reinforcing subspecies differences.
A kinetic study on how C/N ratio affects energy consumption of composting of rose oil‐processing wastes with caged layer manure and straw
Authors: Onursal E. , Ekinci K. 
Published: October 2016

Composting process parameters such as C/N ratio, moisture content, and temperature are well studied, but limited knowledge exists on energy consumption of the process itself. In this study, co‐composting of rose oil‐processing wastes (ROPW) with caged layer manure and straw was performed to optimize the system in terms of energy use. Intermittent aeration applied to the five compost mixtures with initial C/N ratios of 12.81, 21.37, 24.66, 29.22, and 37.41 was conducted using fifteen identical cylindrical reactors with volume of 60 L. O2 and CO2 concentrations, compost temperature, dry matter loss, organic matter loss, electrical conductivity, and pH were measured. A first‐order kinetic model based on material mass balance was applied to determine kinetic parameters such as decomposition rate and compost equilibrium mass. An equation describing specific energy per initial dry mass of composting as a function of initial C/N ratio was presented and used to optimize initial C/N ratio to maximize composting of ROPW to reach a given level of compost mass ratio. The maximum decomposition, based on dry matter loss, occurred at the initial C/N ratio of 30.18 was 0.032 kg kg−1 day−1. Initial C/N ratio to minimize specific energy use of ROPW composting with caged layer to reach a given level of compost ratio of 0.82 was 29.11. Composting operation can be performed at this initial C/N ratio (29.11) to minimize airflow to keep the power requirement low while still operating the system efficiently. This helps to reduce the energy required for ROPW composting with caged layer to reach a given compost mass ratio. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 129–137, 2017
Floodplain downed wood volumes: a comparison across three biomes
Authors: Lininger Katherine B. , Wohl Ellen , Sutfin Nicholas A. , Rose Joshua R. 
Published: October 2016

AbstractDowned large wood (LW) in floodplains provides habitat and nutrients for diverse organisms, influences hydraulics and sedimentation during overbank flows, and affects channel form and lateral migration. Very few studies, however, have quantified LW volumes in floodplains that are unaltered by human disturbance. We compare LW volumes in relatively unaltered floodplains of semiarid boreal lowland, subtropical lowland, and semiarid temperate mountain rivers in the United States. Average volumes of downed LW are 42.3 m3 ha−1, 50.4 m3 ha−1, and 116.3 m3 ha−1 in the semiarid boreal, subtropical, and semiarid temperate sites, respectively. Observed patterns support the hypothesis that the largest downed LW volumes occur in the semiarid temperate mountain sites, which is likely linked to a combination of moderate‐to‐high net primary productivity, temperature‐limited decomposition rates, and resulting slow wood turnover time. Floodplain LW volumes differ among vegetation types within the semiarid boreal and semiarid temperate mountain regions, reflecting differences in species composition. Lateral channel migration and flooding influence vegetation communities in the semiarid boreal sites, which in turn influences floodplain LW loads. Other forms of disturbance such as fires, insect infestations, and blowdowns can increase LW volumes in the semiarid boreal and semiarid temperate mountain sites, where rates of wood decay are relatively slow compared with the subtropical lowland sites. Although sediment is the largest floodplain carbon reservoir, floodplain LW stores substantial amounts of organic carbon and can influence floodplain sediment storage. In our study sites, floodplain LW volumes are lower than those in adjacent channels, but are higher than those in upland (i.e. non‐floodplain) forests. Given the important ecological and physical effects of floodplain LW, efforts to add LW to river corridors as part of restoration activities, and the need to quantify carbon stocks within river corridors, we urge others to quantify floodplain and instream LW volumes in diverse environments. Copyright © 2016 John Wiley & Sons, Ltd.
The effect of particle size on the genotoxicity of gold nanoparticles
Authors: Xia Qiyue , Li Hongxia , Liu Ying , Zhang Shuyang , Feng Qiyi , Xiao Kai 
Published: October 2016

AbstractDespite the increasing biomedical applications of gold nanoparticles (AuNPs), their toxicological effects need to be thoroughly understood. In the present study, the genotoxic potential of commercially available AuNPs with varying size (5, 20, and 50 nm) were assessed using a battery of in vitro and in vivo genotoxicity assays. In the comet assay, 20 and 50 nm AuNPs did not induce obvious DNA damage in HepG2 cells at the tested concentrations, whereas 5 nm NPs induced a dose‐dependent increment in DNA damage after 24‐h exposure. Furthermore, 5 nm AuNPs induced cell cycle arrest in G1 phase in response to DNA damage, and promoted the production of reactive oxygen species (ROS). In the chromosomal aberration test, AuNPs exposure did not increase in the frequency of chromosomal aberrations in Chinese hamster lung (CHL) cells. In the standard in vivo micronucleus test, no obvious increase in the frequency of micronucleus formation was found in mice after 4 day exposure of AuNPs. However, when the exposure period was extended to 14 days, 5 nm AuNPs presented significant clastogenic damage, with a dose‐dependent increase of micronuclei frequencies. This finding suggests that particle size plays an important role in determining the genotoxicity of AuNPs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 710–719, 2017.
Lung inflammation caused by long‐term exposure to titanium dioxide in mice involving in NF‐κB signaling pathway
Authors: Liu Dong , Zhou Jie‐Lu , Hong Fashui , Zhang Yu‐Qing 
Published: October 2016

AbstractTitanium dioxide nanoparticles (TiO2 NPs) are used in many fields, such as paints, medicine additives, food additives, sunscreens, and agriculture. The aim of this study was to investigate the mechanism behind the formation of inflammation induced by TiO2 NPs. ICR mice were exposed to TiO2 NPs through intragastric administration at 2.5, 5, and 10 mg/kg body weight every day for 90 consecutive days. The experiment suggested that long‐term exposure to TiO2 NPs resulted in an obvious inflammatory response in mice lung tissues, which led to a thickened alveoli septum, lung hyperemia, and titanium accumulation. Furthermore, our results show that TiO2 NPs exposure remarkably altered the expression of inflammation‐related cytokines, with increases in proinflammatory cytokines—such as nucleic factor‐κB, interferon‐α, interferon‐β, interleukin‐1β, interleukin‐6, cyclo‐oxygen‐ase, interleukin‐8, interferon‐inducible protein‐10, and platelet‐derived growth factor AB—and decreases in anti‐inflammatory cytokines—such as inhibitor of NF‐κB suppressor of cytokine signaling 1, endothelin 1, peroxisome proliferators‐activated receptors‐γ, and peroxisome proliferators‐activated receptors coactivator‐1α. This finding indicated that TiO2 NPs cause lung inflammation in mice after intragastric administration, primarily through the NF‐κB signaling pathways. Therefore, more attention should be placed on the application of TiO2 NPs and their potential long‐term effects, especially in human beings. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 720–727, 2017.
Effect of matrix metalloproteinase‐mediated matrix degradation on glioblastoma cell behavior in 3D PEG‐based hydrogels
Authors: Wang Christine , Tong Xinming , Jiang Xinyi , Yang Fan 
Published: October 2016

AbstractGlioblastoma (GBM) is the most common and aggressive form of primary brain tumor with median survival of 12 months. To improve clinical outcomes, it is critical to develop in vitro models that support GBM proliferation and invasion for deciphering tumor progression and screening drug candidates. A key hallmark of GBM cells is their extreme invasiveness, a process mediated by matrix metalloproteinase (MMP)‐mediated degradation of the extracellular matrix. We recently reported the development of a MMP‐degradable, poly(ethylene‐glycol)‐based hydrogel platform for culturing GBM cells. In the present study, we modulated the percentage of MMP‐degradable crosslinks in 3D hydrogels to analyze the effects of MMP‐degradability on GBM fates. Using an immortalized GBM cell line (U87) as a model cell type, our results showed that MMP‐degradability was not required for supporting GBM proliferation. All hydrogel formulations supported robust GBM proliferation, up to 10 fold after 14 days. However, MMP‐degradability was essential for facilitating tumor spreading, and 50% MMP‐degradable hydrogels were sufficient to enable both robust tumor cell proliferation and spreading in 3D. The findings of this study highlight the importance of modulating MMP‐degradability in engineering 3D in vitro brain cancer models and may be applied for engineering in vitro models for other cancer types. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 770–778, 2017.