bluuebunny/crossref_metadata_2025 huggingface dataset:
Empirical prediction of coseismic landslide dam formation
Authors: Fan Xuanmei , Rossiter David G. , van Westen Cees J. , Xu Qiang , Görüm Tolga
Published: April 2014

In this study we develop an empirical method to estimate the volume threshold for predicting coseismic landslide dam formation using landscape parameters obtained from digital elevation models (DEMs). We hypothesize that the potential runout and volume of landslides, together with river features, determine the likelihood of the formation of a landslide dam. To develop this method, a database was created by randomly selecting 140 damming and 200 non‐damming landslides from 501 landslide dams and > 60 000 landslides induced by theMw7.9 2008 Wenchuan earthquake in China. We used this database to parameterize empirical runout models by stepwise multivariate regression. We find that factors controlling landslide runout are landslide initiation volume, landslide type, internal relief (H) and theH/Lratio (betweenHand landslide horizontal distance to river,L). In order to obtain a first volume threshold for a landslide to reach a river, the runout regression equations were converted into inverse volume equations by taking the runout to be the distance to river. A second volume threshold above which a landslide is predicted to block a river was determined by the correlation between river width and landslide volume of the known damming landslides. The larger of these two thresholds was taken as the final damming threshold. This method was applied to several landslide types over a fine geographic grid of assumed initiation points in a selected catchment. The overall prediction accuracy was 97.4% and 86.0% for non‐damming and damming landslides, respectively. The model was further tested by predicting the damming landslides over the whole region, with promising results. We conclude that our method is robust and reliable for the Wenchuan event. In combination with pre‐event landslide susceptibility and frequency–size assessments, it can be used to predict likely damming locations of future coseismic landslides, thereby helping to plan emergency response. Copyright © 2014 John Wiley & Sons, Ltd.
A model to resolve organochlorine pharmacokinetics in migrating humpback whales
Authors: Cropp Roger , Nash Susan Bengtson , Hawker Darryl
Published: April 2014

Humpback whales are iconic mammals at the top of the Antarctic food chain. Their large reserves of lipid-rich tissues such as blubber predispose them to accumulation of lipophilic contaminants throughout their lifetime. Changes in the volume and distribution of lipids in humpback whales, particularly during migration, could play an important role in the pharmacokinetics of lipophilic contaminants such as the organochlorine pesticide hexachlorobenzene (HCB). Previous models have examined constant feeding and nonmigratory scenarios. In the present study, the authors develop a novel heuristic model to investigate HCB dynamics in a humpback whale and its environment by coupling an ecosystem nutrient-phytoplankton-zooplankton-detritus (NPZD) model, a dynamic energy budget (DEB) model, and a physiologically based pharmacokinetic (PBPK) model. The model takes into account the seasonal feeding pattern of whales, their energy requirements, and fluctuating contaminant burdens in the supporting plankton food chain. It is applied to a male whale from weaning to maturity, spanning 20 migration and feeding cycles. The model is initialized with environmental HCB burdens similar to those measured in the Southern Ocean and predicts blubber HCB concentrations consistent with empirical concentrations observed in a southern hemisphere population of male, migrating humpback whales. Results show for the first time some important details of the relationship between energy budgets and organochlorine pharmacokinetics. Environ Toxicol Chem 2014;33:1638–1649. © 2014 SETAC
Occurrence and distribution of organophosphate flame retardants/plasticizers in wastewater treatment plant sludges from the Pearl River Delta, China
Authors: Zeng Xiangying , He Lixiong , Cao Shuxia , Ma Shengtao , Yu Zhiqiang , Gui Hongyan , Sheng Guoying , Fu Jiamo
Published: April 2014

Organophosphate esters (OPs) are widely used as flame retardants or plasticizers and are ubiquitously distributed in the environment. In the present study, the occurrence and distribution of 7 widely used OPs were analyzed in sludge samples collected from 19 municipal wastewater treatment plants in the Pearl River Delta, South China. All analytes were detected in these samples, and the total concentration of OPs ranged from 96.7 µg/kg to 1312.9 µg/kg dry weight, with a mean value of 420.1 µg/kg dry weight. In most sludge samples OPs exhibited a similar distribution pattern, for example, tris(2-butoxyethyl) phosphate (TBEP) and triphenyl phosphate (TPhP) were identified as the dominant compounds. However, the results also indicated significantly higher levels of OPs in specific sludges, such as tri-n-butyl phosphate (804.9 µg/kg), TBEP (783.7 µg/kg), TPhP (656.7 µg/kg), and tritolyl phosphate (265.0 µg/kg), which implied different discharge sources in the studied areas. Environ Toxicol Chem 2014;33:1720–1725. © 2014 SETAC
Effect of moisture on the heat capacity and the regeneration heat required for CO2 capture process using PEI impregnated mesoporous precipitated silica
Authors: Quang Dang Viet , Dindi Abdallah , Rayer Aravind V , Hadri Nabil El , Abdulkadir Abdurahim , Abu‐Zahra Mohammad R.M.
Published: April 2014

In this study, we report the effect of the moisture of polyethylenimine (PEI) impregnated mesoporous precipitated silica used for CO2 adsorption on the heat capacity and the heat required to regenerate the adsorbent. The results indicate that the heat capacity of the absorbent increases as its moisture content increases. The increase in moisture results in the rise of the vaporization heat of water and the elevated heat capacity results in higher sensible heat. For these reasons, the total regeneration heat required for CO2 capture process increases significantly. The adsorbent has a maximum CO2 adsorption capacity at 75 °C. CO2 capture process using PEI impregnated mesoporous precipitated silica requires a minimum energy to regenerate the adsorbent; it reduces 46% of the energy compared to a process using an aqueous MEA 30 wt%, as the process operates at 75 °C.
Impact of soil surface characteristics on soil water content variability in agricultural fields
Authors: Manns Hida R. , Berg Aaron A. , Bullock Paul R. , McNairn Heather
Published: April 2014

The accuracy of soil water content (WC) interpretation from satellites and its application in hydrological modelling is dependent on our understanding of the effects of field‐scale surface soil properties on soil WC variability. Soil texture, surface roughness and surface residue were evaluated for their influence on soil WC variability with data obtained from satellite ground verification sampling near Carman, Manitoba, within a 28 km2 area. Over the course of five selected dates from 23 April to 18 May 2008, soil WC and other physical variables were obtained in 38 agricultural fields covering three distinct soil textural classifications. Within each field, at each of 16 sampling locations, four individual soil WC measurements were taken, including sampling points with and without the influence of crop residue left on the soil surface. A principal component analysis and multiple linear regression both identified soil texture as the primary physical process controlling variability in soil WC and coefficient of variation (CV) among fields during the campaign. Residue cover was also a significant factor representing a second principal component that explained 37% of variability in average soil WC and contributed to 31% of variability in CV. Whereas soil texture predominated in soil WC and CV on most sampling dates, residue cover was of equal significance as texture in dry soils. This study identified specific effects of tillage and residue management contributing to field‐scale soil WC variability that could contribute significant improvements to interpretation of remotely sensed soil WC and subsequent scaling efforts over agricultural regions. Copyright © 2014 John Wiley & Sons, Ltd.
Conditioning temperature‐index model parameters on synoptic weather types for glacier melt simulations
Authors: Matthews T. , Hodgkins R. , Wilby R. L. , Guðmundsson S. , Pálsson F. , Björnsson H. , Carr S.
Published: April 2014

Temperature‐index models are widely favoured as a pragmatic means of simulating glacier melt because of their generally good performance, computational simplicity and limited demands for in situ data. However, their coefficients are normally treated as temporally stationary, unrealistically assuming a constancy of the prevailing weather. We address this simplification by prescribing model coefficients as a function of synoptic weather type, in a procedure that utilizes reanalysis data and preserves the minimal data requirements of temperature‐index models. Using a cross‐validation procedure at Vestari Hagafellsjökull, Iceland, and Storglaciären, Sweden, we demonstrate that applying transient model coefficients, for three temperature‐index models, results in statistically significant increases in the skill with which melt is modelled: Median simulation improvements in the Nash–Sutcliffe efficiency coefficient of 7.3 and 23.6% are achieved when hourly and daily melt totals are evaluated respectively. Our weather‐type modelling approach also yields insight to processes driving parameter variability, revealing dependence that is consistent with a priori considerations of the surface energy balance. We conclude that incorporating weather types into temperature‐index models holds promise for improving their performance, as well as enhancing understanding variability in coefficient values. Copyright © 2014 John Wiley & Sons, Ltd.
Real‐time river bed scour monitoring and synchronous maximum depth data collected during Typhoon Soulik in 2013
Authors: Yang Han‐Chung , Su Chih‐Chiang
Published: April 2014

A critical concern regarding river bed stabilization and river engineering is the short‐term general scour that occurs in a field setting far from a river‐crossing structure or embankment during a typhoon‐induced flood. This study investigated the improvement of existing techniques that have been used to measure river bed scour. One of these techniques is the numbered‐brick column or scour chains method, in which only the maximum general scour depth of river bed is observed. A wireless tracer for monitoring real‐time scour was set‐up with a numbered‐brick column and was employed to collect synchronous data. The proposed method was successfully used to observe both real‐time scour and the maximum depth at flood peak. This observation was conducted at a steep gravel‐bed reach of the Shuideliaw Embankment on the intermittent Choshui River in Central Taiwan during Typhoon Soulik, which occurred in 2013. Future studies must be conducted to complete the development of an automatic real‐time scour and flood monitoring system for use in severe weather and flow conditions; this would facilitate the identification of river bed scour during conditions of unstable flow and the improvement of flood prevention engineering, bridge closure detection and emergency evacuation procedures. Copyright © 2014 John Wiley & Sons, Ltd.
Spatial and temporal variation in particle size and particulate organic matter content in suspended particulate matter from peatland‐dominated catchments in Finland
Authors: Marttila Hannu , Kløve Bjørn
Published: April 2014

Properties of suspended particulate matter play a vital role in transport processes, but information from boreal lowland river systems with high organic loads is limited. This study analysed data from 2 years of sampling at 30 locations in Finland (204 samples in total) using suspended particulate matter samplers to determine effective and absolute particle size and organic fractions. Mean d50 value was 22 and 49 µm for absolute and effective particle size, respectively. The organic fraction content ranged from 2.1% to 36% (mean 9.6%), highlighting the importance of particle organic matter for suspended particulate matter flux in the region. The results indicated that the suspended particulate matter particle size distribution and load in the study region is dominated by composite particles. There were considerable spatial and temporal variations in transport of organic fractions, effective particle size and degree of aggregation (range 1.5–93%). Headwaters and, in particular, late summer and spring flood conditions with flow peaks produced the largest composite particles, whereas agriculture‐dominated sites produced smaller but more tightly compacted particles. Organic plant fibres appeared to play a vital role in floc formation in peat‐covered catchments, whereas in agriculture‐dominated catchments, land use‐derived aggregates dominated the composition. This study provides empirical evidence of the importance of effective particle size measurement in understanding the dynamics of suspended particulate matters in boreal lowland river systems. Copyright © 2014 John Wiley & Sons, Ltd.
Garlic Powder as a Safe Environment Green Corrosion Inhibitor for Mild Steel in Acidic Media; Adsorption and Quantum Chemical Studies
Authors: Yaro Aprael S. , Khadom Anees A. , Wael Rafal K.
Published: April 2014

The corrosion inhibition of mild steel in H3PO4 solution by garlic powder was investigated using weight loss and polarization techniques. The adsorption of garlic powder was found to obey Langmuir adsorption isotherm. Maximum inhibition efficiency was 75% at 50 °C and 250 ppm inhibitor concentration. The values of heat of adsorption were negative indicating the spontaneous adsorption process. Quantum chemical calculations were used successfully to evaluate the theoretical inhibitor efficiency. Mathematical and statistical analyses were also used to represent the corrosion rate data with high correlation coefficients. Polarization measurements showed that garlic powder was a mixed — type inhibitor.
Estimation of the Moments of the Residence Time and First Passage Time from Experimentally Measurable Permeation Parameters via a New Formulation of the Transmission Matrix
Authors: Chen Jenn‐Shing , Yeh Kwei‐Tin , Chang Wen‐Yih , Baird James K.
Published: April 2014

Siegel's analysis on membrane transport in the Laplace domain [J. Phys. Chem. 95 (1991) 2556] in terms of transmission matrix, T(s), has been extended to a more useful formulation. This is achieved by combining uses of the matrix transport equations appropriate for void initial condition, or for saturated equilibrium, or of Dirac delta functional type and the theorem det[T(s)] = 1. This formulation enables us to expand T(s) in power series of the Laplace variable, s, with the expansion coefficients as the algebraic functions of the experimentally measurable transport parameters. Utility of the formulation is illustrated in the estimation of the experimentally inaccessible time moments for the first passage or residence times. It was also applied to the percutaneous drug delivery to obtain from the experimental data. The higher moments of the time lag or time lead using a graphic method.
Synthesis and Characterization of Poly(ethylene terephthalate)/Modified Lithium‐Aluminum‐Layered Double Hydroxide Nanocomposites Prepared Using In‐situ Polymerization
Authors: Tsai Tsung‐Yen , Shiu Wei‐Chuan
Published: April 2014

Layered double hydroxides are a type of layered stacked compound, which can be intercalated with organic‐molecule modifiers. An ion‐exchange process for layered double hydroxide (LDH) was used to intercalate water‐soluble sulfanilic acid salt (SAS) and dimethyl 5‐sulfoisopthalate (DMSI) into lithium aluminum layered double hydroxides (LiAl LDHs). In this work, a hydrothermal process was used to modify LiAl LDHs, and the modified LiAl LDHs were treated with either SAS or DMSI through an ion‐exchange process and were then intercalated using bis‐hydroxyethylene terephthalate (BHET). The results indicate that the modified LiAl LDHs improved the interlayer compatibility between the PET and LiAl LDH layers; thus, enabling the oligomer molecules to more easily enter the gallery of the LiAl LDH layers so that polymer chains could be included between the LDH layers during polymerization of the matrix. The better barrier, mechanical properties, and thermal stability of these new types of PET nanocomposites are discussed.
Analysis of Global Changes in Gene Expression Induced by Human Polynucleotide Phosphorylase (hPNPaseold‐35)
Authors: Sokhi Upneet K. , Bacolod Manny D. , Emdad Luni , Das Swadesh K. , Dumur Catherine I. , Miles Michael F. , Sarkar Devanand , Fisher Paul B.
Published: April 2014

As a strategy to identify gene expression changes affected by human polynucleotide phosphorylase (hPNPaseold‐35), we performed gene expression analysis of HeLa cells in which hPNPaseold‐35 was overexpressed. The observed changes were then compared to those of HO‐1 melanoma cells in which hPNPaseold‐35 was stably knocked down. Through this analysis, 90 transcripts, which positively or negatively correlated with hPNPaseold‐35 expression, were identified. The majority of these genes were associated with cell communication, cell cycle, and chromosomal organization gene ontology categories. For a number of these genes, the positive or negative correlations with hPNPaseold‐35 expression were consistent with transcriptional data extracted from the TCGA (The Cancer Genome Atlas) expression datasets for colon adenocarcinoma (COAD), skin cutaneous melanoma (SKCM), ovarian serous cyst adenocarcinoma (OV), and prostate adenocarcinoma (PRAD). Further analysis comparing the gene expression changes between Ad.hPNPaseold‐35 infected HO‐1 melanoma cells and HeLa cells overexpressing hPNPaseold‐35 under the control of a doxycycline‐inducible promoter, revealed global changes in genes involved in cell cycle and mitosis. Overall, this study provides further evidence that hPNPaseold‐35 is associated with global changes in cell cycle‐associated genes and identifies potential gene targets for future investigation. J. Cell. Physiol. 229: 1952–1962, 2014. © 2014 Wiley Periodicals, Inc.
1‐Factor and Cycle Covers of Cubic Graphs
Authors: Steffen Eckhard
Published: April 2014

Let G be a bridgeless cubic graph. Consider a list of k 1‐factors of G. Let be the set of edges contained in precisely i members of the k 1‐factors. Let be the smallest over all lists of k 1‐factors of G. Any list of three 1‐factors induces a core of a cubic graph. We use results on the structure of cores to prove sufficient conditions for Berge‐covers and for the existence of three 1‐factors with empty intersection. Furthermore, if , then is an upper bound for the girth of G. We also prove some new upper bounds for the length of shortest cycle covers of bridgeless cubic graphs. Cubic graphs with have a 4‐cycle cover of length and a 5‐cycle double cover. These graphs also satisfy two conjectures of Zhang . We also give a negative answer to a problem stated in .
Counterexamples to the List Square Coloring Conjecture
Authors: Kim Seog‐Jin , Park Boram
Published: April 2014

The square G2 of a graph G is the graph defined on such that two vertices u and v are adjacent in G2 if the distance between u and v in G is at most 2. Let and be the chromatic number and the list chromatic number of a graph H, respectively. A graph H is called chromatic‐choosable if . It is an interesting problem to find graphs that are chromatic‐choosable. Kostochka and Woodall (Choosability conjectures and multicircuits, Discrete Math., 240 (2001), 123–143) conjectured that for every graph G, which is called List Square Coloring Conjecture. In this article, we give infinitely many counter examples to the conjecture. Moreover, we show that the value can be arbitrarily large.
Effects of helicopter capture and handling on movement behavior of mule deer
Authors: Northrup Joseph M. , Anderson Charles R. , Wittemyer George
Published: April 2014

Research on wildlife movement, physiology, and reproductive biology often requires capture and handling of animals. Such invasive treatment can alter behavior, which may bias results or invalidate assumptions regarding representative behaviors. To assess the impacts of handling on mule deer (Odocoileus hemionus), a focal species for research in North America, we investigated pre‐ and post‐recapture movements of collared individuals, and compared them to deer that were not recaptured (controls). We compared pre‐ and post‐recapture movement rates (m/hr) and 24‐hour straight‐line displacement among recaptured and control deer. In addition, we examined the time it took recaptured deer to return to their pre‐recapture home range. Both daily straight‐line displacement and movement rate were marginally elevated relative to monthly averages for 24 hours following recapture, with non‐significant elevation continuing for up to 7 days. Comparing movements averaged over 30 days before and after recapture, we found no differences in displacement, but movement rates demonstrated seasonal effects, with faster movements post‐ relative to pre‐recapture in March and slower movements post‐ relative to pre‐recapture in December. Relative to control deer movements, recaptured deer movement rates in March were higher immediately after recapture and lower in the second and third weeks following recapture. The median time to return to the pre‐recapture home range was 13 hours, with 71% of deer returning in the first day, and 91% returning within 4 days. These results indicate a short period of elevated movements following recaptures, likely due to the deer returning to their home ranges, followed by weaker but non‐significant depression of movements for up to 3 weeks. Censoring of the first day of data post‐capture from analyses is strongly supported, and removing additional days until the individual returns to its home range will control for the majority of impacts from capture. © 2014 The Wildlife Society.
Reverse Pricing and Revenue Sharing in a Vertical Market
Authors: Liu Qihong , Shuai Jie
Published: April 2014

Advancing in information technology has empowered firms with unprecedented flexibility when interacting with each other. We compare welfare results in a vertical market (e.g., manufacturers and retailers) for several types of pricing strategies depending upon the following: (1) which side (retailers or manufacturers) chooses retail prices; and (2) whether there is revenue sharing or linear pricing between the two sides. Our results are as follows. Under revenue sharing, retail prices (and thus industry profits) are higher if and only if they are chosen by the side featuring less competition. Under linear pricing, however, retail prices are higher if they are chosen by the side featuring more competition (for linear demand functions). Relative to linear pricing, revenue sharing always leads to lower retail prices, higher consumer surplus and social surplus. However, the comparison on industry profits depends on the demand elasticity ratios. Revenue sharing raises industry profits when the elasticity ratios are small, but the results are reversed when the elasticity ratios are large. Copyright © 2014 John Wiley & Sons, Ltd.
Magnetic resonance support vector machine discriminates essential tremor with rest tremor from tremor‐dominant Parkinson disease
Authors: Cherubini Andrea , Nisticó Rita , Novellino Fabiana , Salsone Maria , Nigro Salvatore , Donzuso Giulia , Quattrone Aldo
Published: April 2014

Background

The aim of the current study was to distinguish patients who had tremor‐dominant Parkinson's disease (tPD) from those who had essential tremor with rest tremor (rET).

Methods

We combined voxel‐based morphometry‐derived gray matter and white matter volumes and diffusion tensor imaging‐derived mean diffusivity and fractional anisotropy in a support vector machine (SVM) to evaluate 15 patients with rET and 15 patients with tPD. Dopamine transporter single‐photon emission computed tomography imaging was used as ground truth.

Results

SVM classification of individual patients showed that no single predictor was able to fully discriminate patients with tPD from those with rET. By contrast, when all predictors were combined in a multi‐modal algorithm, SVM distinguished patients with rET from those with tPD with an accuracy of 100%.

Conclusions

SVM is an operator‐independent and automatic technique that may help distinguish patients with tPD from those with rET at the individual level. © 2014 International Parkinson and Movement Disorder Society
Strategies in the Design of Small‐Molecule Fluorescent Probes for Peptidases
Authors: Chen Laizhong , Li Jing , Du Lupei , Li Minyong
Published: April 2014

Peptidases, which can cleave specific peptide bonds in innumerable categories of substrates, usually present pivotal positions in protein activation, cell signaling and regulation as well as in the origination of amino acids for protein generation or application in other metabolic pathways. They are also involved in many pathological conditions, such as cancer, atherosclerosis, arthritis, and neurodegenerative disorders. This review article aims to conduct a wide‐ranging survey on the development of small‐molecule fluorescent probes for peptidases, as well as to realize the state of the art in the tailor‐made probes for diverse types of peptidases.
The Decay of mass for a nonlinear fractional reaction–diffusion equation
Authors: Jleli Mohamed , Samet Bessem
Published: April 2014

We study the large time behavior of non‐negative solutions to the nonlinear fractional reaction–diffusion equation ∂tu = − tσ( − Δ)α ∕ 2u − h(t)up (α ∈ (0,2]) posed on and supplemented with an integrable initial condition, where σ ≥ 0, p > 1, and h : [0, ∞ ) → [0, ∞ ). Defining the mass , under certain conditions on the function h, we show that the asymptotic behavior of the mass can be classified along two cases as follows:

if , then there exists M ∞  ∈ (0, ∞ ) such that ;

if , then .

Copyright © 2014 John Wiley & Sons, Ltd.
Wave‐breaking phenomenon for a generalized spatially periodic Camassa–Holm system
Authors: Yu Shengqi
Published: April 2014

Considered herein is a generalized two‐component Camassa–Holm system in spatially periodic setting. We first prove two conservation laws; then under proper assumptions on the initial data, we show the precise blow‐up scenarios and sufficient conditions guaranteeing the formation of singularities to the solutions of the generalized Camassa–Holm system. Copyright © 2014 John Wiley & Sons, Ltd.
Painlevé analysis and exact solutions of a predator–prey system with diffusion
Authors: Kudryashov N.A. , Zakharchenko A.S.
Published: April 2014

A system of equations for description of the predator–prey relations is considered. The model corresponds to the modified Lotka–Volterra system with logistic growth of the prey and with both predator and prey dispersing by diffusion. The Painlevé analysis of the system of equations is studied. Exact traveling wave solutions are found by means of the Q‐function method. Copyright © 2014 John Wiley & Sons, Ltd.
Study of the propagation centre in the anionic polymerization of (meth)acrylic monomers: NMR and MNDO study of the complexes of methyl 2‐lithioisobutyrate and of the living methyl methacrylate oligomer with lithium tert‐butoxide
Authors: Kříž J. , Dybal J. , Janata M. , Vlček P.
Published: April 2014

Methyl 2‐lithioisobutyrate (LIMIB) is shown to form 3:1, 2:2 and 1:3 complexes with lithium tert‐butoxide (LTB) in THF, depending on their molar ratio and storage time. The rate of formation of the complexes varies inversely as their stability: the 3:1 (LIMIB:LTB) complex is formed immediately but is not very stable; the full formation of the 1:3 complex takes about 20 h at −15°C but the product can be kept for several hours at room temperature without marked change. 1H, 13C, 6Li and 7Li NMR and MNDO results suggest that the core of any kind of the complex is formed by a cubic (Li‐0)4 structure with each of the four Li atoms bound to three equivalent oxygens. The structure of the complexes with less tert‐butoxide is less tightly packed. The complexes do not exhibit intermolecular exchange of Li atoms; their intramolecular exchange was not found but cannot be excluded. Preliminary results are presented for living MMA oligomers prepared by initiation with the LIMIB‐LTB system. The structure of these oligomers is not significantly affected by the equilibrium state of the initiation system. The living centre is found to be coordinated both to LTB and to the penultimate ester group. Although improved in stability by LTB coordination, the living oligomers exhibit marked self‐termination in THF even at −70°C.
Domain size of dynamic heterogeneities in antiplasticized polycarbonate by proton spin diffusion
Authors: Liu Yu , Inglefield Paul T. , Jones Alan A. , Kambour R. P.
Published: April 2014

Proton spin diffusion measurements were made using the Goldman—Shen technique of bisphenol‐A polycarbonate containing 10 wt% trioctyl phosphate at temperatures below the glass transition temperature. The proton lineshapes reveal the existence of dynamic heterogeneities in the glass and spin diffusion can be observed from the more mobile to the less mobile domain. The time‐scale for spin diffusion is 4–10 ms and the mobile domain size is estimated at 11 Å at 339 K. This estimate is consistent with a mobile domain of approximately two diluent molecules and 11 polymer repeat units. This grouping can be compared with the results of a statistical lattice model used to estimate local environments at this composition.
Assessment of diffusion tensor MR imaging (DTI) in liver fibrosis with minimal confounding effect of hepatic steatosis
Authors: Lee Yunjung , Kim Hyeonjin
Published: April 2014

Purpose

Given the potential confounding effect of fat on apparent diffusion coefficient (ADC) in the liver, we have assessed diffusion tensor imaging in liver fibrosis with minimal effect of fat on ADC and fractional anisotropy (FA).

Methods

Thirty‐six mice were used, among which 20 mice were CCl4 treated for fibrosis induction. Diffusion tensor imaging was performed at 9.4T using a spin‐echo diffusion tensor imaging sequence with six gradient directions. Hepatic fat fraction obtained by MR spectroscopy was used as hepatic fat content. Fibrosis scores were obtained from histopathology.

Results

The hepatic fat fractions of the two animal groups were below 5.5% and not different (5.3 ± 1.5 vs. 4.6 ± 1.1%; P = 0.115). Fibrosis scores were higher in CCl4‐treated mice (0.0 ± 0.0 vs. 2.1 ± 0.7; P < 0.001). Nonetheless, there was no difference in ADC between the two groups (0.711 ± 0.068 × 10−3 vs. 0.718 ± 0.095 × 10−3 mm2 s−1; P = 0.911). The treated group had a lower FA than control (0.552 ± 0.050 vs. 0.586 ± 0.013; P = 0.023). ADC was not correlated with hepatic fat fraction and fibrosis. FA was correlated with hepatic fat fraction (r = 0.418, P = 0.011) and fibrosis (r = −0.411, P = 0.012).

Conclusion

FA may be more sensitive to mild‐to‐moderate liver fibrosis than ADC. In addition to ADC, FA may also be sensitive to hepatic fat content, and therefore need careful interpretation in liver fibrosis with concomitant fatty liver. Magn Reson Med 73:1602–1608, 2015. © 2014 Wiley Periodicals, Inc.
Detection of transgene expression using hyperpolarized 13C urea and diffusion‐weighted magnetic resonance spectroscopy
Authors: Patrick P. Stephen , Kettunen Mikko I. , Tee Sui‐Seng , Rodrigues Tiago B. , Serrao Eva , Timm Kerstin N. , McGuire Sarah , Brindle Kevin M.
Published: April 2014

Purpose

To assess the potential of a gene reporter system, based on a urea transporter (UTB) and hyperpolarized [13C]urea.

Methods

Mice were implanted subcutaneously with either unmodified control cells or otherwise identical cells expressing UTB. After injection of hyperpolarized [13C]urea, a spin echo sequence was used to measure urea concentration, T1, and diffusion in control and UTB‐expressing tissue.

Results

The apparent diffusion coefficient of hyperpolarized urea was 21% lower in tissue expressing UTB, in comparison with control tissue (P < 0.05, 1‐tailed t‐test, n = 6 in each group). No difference in water apparent diffusion coefficient or cellularity between these tissues was found, indicating that they were otherwise similar in composition.

Conclusion

Expression of UTB, by mediating cell uptake of urea, lowers the apparent diffusion coefficient of hyperpolarized 13C urea in tissue and thus the transporter has the potential to be used as a magnetic resonance‐based gene reporter in vivo. Magn Reson Med 73:1401–1406, 2015. © 2014 Wiley Periodicals, Inc.
The three most important things about origins: location, location, location
Authors: Rhind Nicholas
Published: April 2014

The reasons why some DNA replication origins fire earlier than others have remained elusive. New work by Gindin et al suggests that the distribution of replication origins, not their timing per se, is the major determinant of the timing of genome replication in human cells.
A domain‐decomposition strategy for a compressible multi‐phase flow interacting with a structure
Authors: Greco M. , Colicchio G. , Faltinsen O.M.
Published: April 2014

The problem of a high‐pressure gas cavity and its interaction with surrounding liquid and a close‐by structure is examined numerically. Even though this is of interest in many practical applications, here, the focus is on an underwater explosion. A one‐way DD strategy coupling a radial and a 3D solver for compressible multiphase flows is proposed, and the different components are successfully validated. This is a time‐space DD, which assumes the explosion that occurs sufficiently far from boundaries. It means that the radial solution is used everywhere until radial symmetry is no more applicable. When acoustic waves reach a close structure, the radial solution initiates the 3D solution near the body and continues to be applied only far from the structure and to provide the boundary conditions for the 3D sub‐domain. The advantage is to limit the computational costs and preserve reliability and accuracy. The radial solution could be applied to assess local damages during the initial acoustic phase; the time‐space DD needs to be used to investigate both local and global consequences on the vessels. The structure is modeled both as a rigid wall and as an orthotropic plate, which provides a good representation of the bottom grillages of ships. Copyright © 2014 John Wiley & Sons, Ltd.
Electrically conductive anti‐reflecting nanostructure for chalcogenide thin‐film solar cells
Authors: Park Ji‐Hyeon , Lee Tae Il , Hwang Sung‐Hwan , Moon Kyeong‐Ju , Myoung Jae‐Min
Published: April 2014

Electrically conducting aluminum (Al)‐doped ZnO nanorods (NRs) film has been introduced as an anti‐reflective (AR) layer for effective light trapping in chalcogenide thin‐film solar cells. Results indicate that the Al‐doping significantly reduced the electrical contact resistance between the Ag top electrode and the AR layer. The Al‐doped ZnO NRs exhibited low average reflectance (4.5%) over the entire visible and near‐infrared range, and changed the nature of electrical contact between the Ag electrode and the AR layer from Schottky to Ohmic. Finally, the CuInS2 solar cell coated with the Al‐doped ZnO NRs exhibited huge enhancement in photovoltaic efficiency from 9.57% to 11.70% due to the lowering series resistance and the increase in the short‐circuit current density, when compared with that of a solar cell without the AR layer. Copyright © 2014 John Wiley & Sons, Ltd.
Generating a detailed protein profile of Fasciola hepatica during the chronic stage of infection in cattle
Authors: Haçarız Orçun , Baykal Ahmet Tarık , Akgün Mete , Kavak Pınar , Sağıroğlu Mahmut Şamil , Sayers Gearóid Patrick
Published: April 2014

Fasciola hepatica is a trematode helminth causing a damaging disease, fasciolosis, in ruminants and humans. Comprehensive proteomic studies broaden our knowledge of the parasite's protein profile, and provide new insights into the development of more effective strategies to deal with fasciolosis. The objective of this study was to generate a comprehensive profile of F. hepatica proteins expressed during the chronic stage of infection in cattle by building on previous efforts in this area. The approach included an improved sample preparation procedure for surface and internal layers of the parasite, the application of nano‐UPLC‐ESI‐qTOF‐MS (nano‐ultra‐performance LC and ESI quadrupole TOF MS) integrated with different acquisition methods and in silico database search against various protein databases and a transcript database including a new assembly of publically available EST. Of a total of 776 identified proteins, 206 and 332 were specific to the surface and internal layers of the parasite, respectively. Furthermore, 238 proteins were common to both layers, with comparative differences of 172 proteins detected. Specific proteins not previously identified in F. hepatica, but shown to be immunomodulatory or potential drug targets for other parasites, are discussed.
Elongator and SPT4/SPT5 complexes as proxy to study RNA polymerase II transcript elongation control of plant development
Authors: Lijsebettens Mieke Van , Dürr Julius , Woloszynska Magdalena , Grasser Klaus D.
Published: April 2014

The elongation phase of the RNA polymerase II (RNAPII) transcription process is dynamic and regulated. Elongator and SUPPRESSOR OF Ty4 (SPT4)/SPT5 are transcript elongation factors that contribute to the regulation of mRNA synthesis by RNA polymerase II in the chromatin context. Recently, the Elongator complex consisting of six subunits and the SPT4/SPT5 heterodimer were isolated from Arabidopsis. Mutant plants affected in the expression of Elongator or SPT4/SPT5 share various auxin‐signaling phenotypes. In line with that observation, auxin‐related genes are prominent among the genes differentially expressed in these mutants. Exemplified by Elongator and SPT4/SPT5, we discuss here the role that transcript elongation factors may play in the control of plant growth and development.
Application of Boltzmann transport theory to disordered thermoelectric materials: Ti(Fe,Co,Ni)Sb half‐Heusler alloys
Authors: Kutorasinski K. , Tobola J. , Kaprzyk S.
Published: April 2014

Boltzmann transport theory with constant relaxation time approximation is applied to calculate electron transport coefficients in disordered multi‐atom alloys. It allows to determine physical quantities, such as electrical conductivity and Seebeck coefficient, when different models of the relaxation time are employed. In order to study the electronic structure and Fermi surface properties in a system containing complex chemical disorder, the Korringa–Kohn–Rostoker method with the coherent potential approximation is used. This methodology is applied to TiFe1−xNixSb half‐Heusler alloys, which exhibit metal‐semiconductor‐metal crossover with a change in type of carriers (from holes to electrons), upon increasing x. Electron transport quantities as well as the electron lifetime related to impurity scattering are calculated. Thermopower is presented on two dimensional maps as a function of temperature and carrier concentration. A beneficial role of Co in enhancement of thermopower of both p‐ and n‐type Ti(Fe,Co,Ni)Sb alloys is predicted, which is mainly due to the valence or conduction bands convergence.
Temperature and magnetic dependence of the resistance and thermopower in the topological insulator Bi1−xSbx nanowires
Authors: Nikolaeva Albina , Konopko Leonid , Huber Tito , Popov Ivan , Bodiul Pavel , Moloshnik Evghenii
Published: April 2014

We report on the electrical transport and thermoelectric properties of Bi1−xSbx nanowires in the semiconductor region made of Bi1−xSbx. Such alloys are classified as topological insulators. The individual Bi–17 at%Sb wires in a glass capillary with diameters ranging from 100 to 1000 nm were prepared by high‐frequency liquid‐phase casting in an argon atmosphere. They were cylindrical single crystals with (1011) orientation along the wire axis. For large‐diameter wires we observed that the temperature‐dependent resistance, R(T), displays the temperature‐activated dependence that is expected of semiconductors. We also found that small‐diameter wires at low temperatures show a sharp deviation from the behavior of the resistance R(T), characteristic of semiconductors. The contrasting behavior of wires of different diameters can be interpreted in terms of the conductance of the surface states in BiSb where the surface states arise through a spin‐orbital Rashba interaction in the surface of BiSb. The thermopower remains negative over the entire temperature range, but it is strongly temperature dependent. The longitudinal magnetoresistance R(H) at low temperature shows quantum Shubnikov–de Haas oscillations only in thin (d < 200 nm) Bi–17 at%Sb nanowires. Only high‐mobility carriers display SdH oscillations. Since we expect the electronic transport in the 200‐nm semiconducting Bi1−xSbx nanowires to be dominated by the surface, this indicates that the surface states have sufficiently high mobility to display SdH.
Theoretical study and simulation of light‐addressable potentiometric sensors
Authors: Guo Yuanyuan , Miyamoto Ko‐ichiro , Wagner Torsten , Schöning Michael J. , Yoshinobu Tatsuo
Published: April 2014

The light‐addressable potentiometric sensor (LAPS) is a semiconductor‐based potentiometric sensor using a light probe with an ability of detecting the concentration of biochemical species in a spatially resolved manner. As an important biomedical sensor, research has been conducted to improve its performance, for instance, to realize high‐speed measurement. In this work, the idea of facilitating the device‐level simulation, instead of using an equivalent‐circuit model, is presented for detailed analysis and optimization of the performance of the LAPS. Both carrier distribution and photocurrent response have been simulated to provide new insight into both amplitude‐mode and phase‐mode operations of the LAPS. Various device parameters can be examined to effectively design and optimize the LAPS structures and setups for enhanced performance.

Distribution of minority carriers inside a Si‐based LAPS structure under illumination with different wavelengths.
Reduced graphene oxide‐based sensing platform for electric cell–substrate impedance sensing
Authors: Lanche Ruben , Pachauri Vivek , Koppenhöfer Dieter , Wagner Patrick , Ingebrandt Sven
Published: April 2014

Graphene, with its unique electrical properties and biocompatibility, has become a material of choice for the development of biosensor platforms. In this study, a microelectrode array based on reduced graphene oxide (rGO) was constructed and used as a platform for electrical monitoring of cell–substrate adhesion. The rGO‐based sensor arrays were designed in order to facilitate sensor pads comparable to the size of individual cells. The sensor chips were fabricated in a scalable manner via site‐specific immobilization of graphene oxide flakes onto microelectrode pairs followed by reduction to rGO. The sensor chips were mounted on a measurement platform equipped with a fluidic cell. Electrical characteristics were recorded and field‐effect behavior was confirmed. Sensors reacted to changes of pH value in the solution. Finally, as a proof‐of‐concept, the graphene oxide‐based sensing platform was used for electrical cell–substrate impedance sensing of individual HEK293 cells in culture.

Schematic view of the rGO‐based sensor chip for electrical cell–substrate adhesion assays.
Annealing and etching treatments on ZnO:Al films deposited by middle frequency sputtering at room temperature
Authors: Zhu H. , Mai Y. , Lai B. , Wan M. , Huang Y. , Zhang L.
Published: April 2014

Large area aluminum doped zinc oxide films (ZnO:Al) were prepared at room temperature in a magnetron sputtering system. The optical and electrical properties as well as etching behaviors and surface structures of ZnO:Al films before and after etching and annealing treatments were systematically investigated. It is found that the ZnO:Al films prepared at room temperature without annealing show a low total transmission. The carrier concentration seems to be inhomogeneous in the films and increases along the growth direction, which can be derived from the shift of plasma resonance wavelength of the etched ZnO:Al films. The annealing treatment leads to a re‐crystallization of the ZnO:Al films and a further increase in carrier concentration. Excess annealing treatment would lead to an increase in resistivity. The etching of annealed ZnO:Al films results in different surface structures varying from hill‐like to small crater‐like shapes with the increasing annealing treatment duration in this case.
Improved cell efficiency of [poly(ethylene oxide)‐succinonitrile]/LiI‐I2 solid polymer electrolyte‐based dye‐sensitized solar cell
Authors: Gupta Ravindra Kumar , Bedja Idriss M.
Published: April 2014

The effect of succinonitrile on cell efficiency, interfacial resistance, and dye regeneration time of [0.5 poly(ethylene oxide):0.5 succinonitrile] blend/LiI‐I2 solid polymer electrolyte is reported for the first time. The addition of succinonitrile increased the electrical conductivity of poly(ethylene oxide)/LiI‐I2 by more than an order in magnitude to ∼3 × 10−4 S cm−1 due to the plasticizing and molecular diffusing properties of succinonitrile. This resulted in an enhancement of the cell efficiency from 0.5% to 2%. The electrochemical impedance spectroscopy revealed a large decrease of interfacial resistances. The transient absorption spectroscopy showed an improvement of the dye regeneration time from 15 to 5 µs.
Broadband light output enhancement for scintillator using whispering‐gallery modes in nanospheres
Authors: Zhu Zhichao , Liu Bo , Cheng Chuanwei , Chen Hong , Gu Mu , Yi Yasha , Mao Rihua
Published: April 2014

An array of monolayer of periodic nanospheres is used to efficiently extract the light from a scintillator of high refractive index with broadband capability. Compared with the plain sample without nanospheres, the enhancement of wavelength‐ and angle‐integrated luminescence by 72 and 68% can be achieved under the excitation of ultraviolet and γ‐ray radiation, respectively. The whispering‐gallery modes for the individual sphere and the periodic arrangement are responsible for the enhancement of light extraction. Such a photonic structure is advantageous over the traditional two‐dimensional photonic crystal.
Properties of Transglutaminase Crosslinked Whey Protein Isolate Coatings and Cast Films
Authors: Schmid Markus , Sängerlaub Sven , Wege Laura , Stäbler Andreas
Published: April 2014

Whey protein is an excellent barrier material, potentially providing the low oxygen permeability and water vapour transmission rate required for packaging materials for sensitive foods. A topical issue is how to reduce the permeability of the whey protein‐based layers. One possible strategy is to apply crosslinking agents. In the present study, the enzyme transglutaminase (TG) was used for this purpose, and the following properties have been measured: oxygen permeability, water vapour transmission rate, effective water vapour diffusion, sorption and permeation coefficients, swellability, light transmission and surface energy. The use of TG was found to reduce the oxygen permeability, reduce the water vapour transmission rate and reduce the effective water vapour diffusion coefficient of the whey protein layers. This study also showed that it was possible to use sorption experiments to approximate the water vapour transmission rates. This work is novel because it deals with the packaging‐related properties of whey films crosslinked with TG. Previous studies have focused on the influence of TG on protein formulations or on the measurement of film properties, which is of little relevance for packaging applications. Copyright © 2014 John Wiley & Sons, Ltd.