bluuebunny/crossref_metadata_2025 huggingface dataset:
Sub‐grid scale parameterization of hillslope runoff and erosion processes for catchment‐scale models of semi‐arid landscapes
Authors: Hutton Christopher , Nicholas Andrew , Brazier Richard
Published: January 2013

The processes of hillslope runoff and erosion are typically represented at coarse spatial resolution in catchment‐scale models due to computational limitations. Such representation typically fails to incorporate the important effects of topographic heterogeneity on runoff generation, overland flow, and soil erosion. These limitations currently undermine the application of distributed catchment models to understand the importance of thresholds and connectivity on hillslope and catchment‐scale runoff and erosion, particularly in semi‐arid environments. This paper presents a method for incorporating high‐resolution topographic data to improve sub‐grid scale parameterization of hillslope overland flow and erosion models. Results derived from simulations conducted using a kinematic wave overland flow model at 0.5 m spatial resolution are used to parameterize the depth–discharge relationship in the overland flow model when applied at 16 m resolution. The high‐resolution simulations are also used to derive a more realistic parameterization of excess flow shear stress for use in the 16 m resolution erosion model. Incorporating the sub‐grid scale parameterization in the coarse‐resolution model (16 m) leads to improved predictions of overland flow and erosion when evaluated using results derived from high‐resolution (0.5 m) model simulations. The improvement in performance is observed for a range of event magnitudes and is most notable for erosion estimates due to the non‐linear dependency between the rates of erosion and overland flow. Copyright © 2013 John Wiley & Sons, Ltd.
Contrasting carbon export dynamics of human impacted and pristine tropical catchments in response to a short‐lived discharge event
Authors: Bass Adrian M. , Munksgaard N.C. , Leblanc M. , Tweed S. , Bird M.I.
Published: January 2013

Utilising newly available instrumentation, the carbon balance in two small tropical catchments was measured during two discharge events at high temporal resolution. Catchments share similar climatic conditions, but differ in land use with one draining a pristine rainforest catchment, the other a fully cleared and cultivated catchment. The necessity of high resolution sampling in small catchments was illustrated in each catchment, where significant chemical changes occurred in the space of a few hours or less. Dissolved and particulate carbon transport dominated carbon export from the rainforest catchment during high flow, but was surpassed by degassing of CO2 less than 4 h after the discharge peak. In contrast, particulate organic carbon dominated export from the cleared catchment, in all flow conditions with CO2 evasion accounting for 5–23% of total carbon flux. Stable isotopes of dissolved inorganic carbon (DIC) in the ephemeral rainforest catchment decreased quickly from ~1.5 ‰ to ~ −16 ‰ in 5 h from the flood beginning. A two‐point mixing model revealed that in the initial pulse, over 90% of the DIC was of rainwater origin, decreasing to below 30% in low flow. In the cultivated catchment, δ13CDIC values varied significantly less (−11.0 to −12.2 ‰) but revealed a complex interaction between surface runoff and groundwater sources, with groundwater DIC becoming proportionally more important in high flow, due to activation of macropores downstream. This work adds to an increasing body of work that recognises the importance of rapid, short‐lived hydrological events in low‐order catchments to global carbon dynamics. Copyright © 2013 John Wiley & Sons, Ltd.
Streamflow sensitivity analysis to climate change for a large water‐limited basin
Authors: Liang Liqiao , Liu Qiang
Published: January 2013

Partitioning precipitation (P) between streamflow (Q) and actual evapotranspiration (Ea) on a basin scale is controlled by climate change in combination with catchment characteristics. Fu's formulation of the Budyko framework was used to estimate Q as a function of two meteorological variables, P and potential evaporation (Ep), and one adjustable parameter reflecting characteristics of catchment conditions (ω). Results show that ω reflects the impacts of catchment characteristics on the partitioning of P between Q and Ea for the different water yielding regions. As predicted, Q was more sensitive to P than to comparable changes in Ep for the whole of the Yellow River Basin (YRB), a water‐limited basin, while it was shown to be highly sensitive to changes in P, Ep, and ω in the low water yielding region (LWYR) of the basin, followed by YRB and the high water yielding region of the basin. The high sensitivity of Q to P, Ep, and ω in LWYR indicates that the management of catchments within these zones is critical to the management of overall basin flow, mitigating impacts of climate change on Q. The Budyko framework, incorporating the adjustable parameter ω, outlines interactions between Q, climate, and characteristics specific to different water yielding regions. It also provides a new approach in understanding hydrological process response to climate change. Due to the obscure physical attributes of ω, an explanation of the parameter using soil or vegetation characteristics will aid in the understanding of the eco‐hydrological behaviour of catchments and help to provide more detailed catchment management options for which to mitigate climate change with respect to concerns regarding agricultural water usage. Copyright © 2013 John Wiley & Sons, Ltd.
Opium: An emerging risk factor for gastric adenocarcinoma
Authors: Shakeri Ramin , Malekzadeh Reza , Etemadi Arash , Nasrollahzadeh Dariush , Aghcheli Karim , Sotoudeh Masoud , Islami Farhad , Pourshams Akram , Pawlita Michael , Boffetta Paolo , Dawsey Sanford M. , Abnet Christian C. , Kamangar Farin
Published: January 2013

Opium use has been associated with higher risk of cancers of the esophagus, bladder, larynx, and lung; however, no previous study has examined its association with gastric cancer. There is also little information on the associations between hookah (water pipe) smoking or the chewing of tobacco products and the risk of gastric cancer. In a case‐control study in Golestan Province of Iran, we enrolled 309 cases of gastric adenocarcinoma (118 noncardia, 161 cardia and 30 mixed‐location adenocarcinomas) and 613 matched controls. Detailed information on long‐term use of opium, tobacco products and other covariates were collected using structured and validated lifestyle and food frequency questionnaires. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were obtained using conditional logistic regression models. Opium use was associated with an increased risk of gastric adenocarcinoma, with an adjusted OR (95% CI) of 3.1 (1.9–5.1), and this increased risk was apparent for both anatomic subsites (cardia and noncardia). There was a dose‐response effect, and individuals with the highest cumulative opium use had the strongest association (OR: 4.5; 95% CI: 2.3–8.5). We did not find a statistically significant association between the use of any of the tobacco products and risk of gastric adenocarcinoma, overall or by anatomic subsite. We showed, for the first time, an association between opium use and gastric adenocarcinoma. Given that opium use is a traditional practice in many parts of the world, these results are of public health significance.
Intake of fruit and vegetables and risk of esophageal squamous cell carcinoma: A meta‐analysis of observational studies
Authors: Liu Jun , Wang Jian , Leng Ye , Lv Changxing
Published: January 2013

Quantification of the association between the intake of fruit and vegetables and risk of esophageal squamous cell carcinoma (ESCC) is controversial even though several studies have explored this association. We summarized the evidence from observational studies in categorical, linear and non‐linear dose–response meta‐analyses. Eligible studies published up to 31 July 2012 were retrieved via computer searches of MEDLINE and EMBASE as well as manual review of references. Random‐effects models were used to calculate summary relative risks (SRRs) and the corresponding 95% confidence intervals (CIs). A total of 32 studies involving 10,037 cases of ESCC were included in this meta‐analysis. The SRRs for the highest vs. lowest intake were 0.56 (95% CI: 0.45–0.69) for vegetable intake and 0.53 (95% CI: 0.44–0.64) for fruit intake (pheterogeneity<0.001 for both). Similar results were observed in a linear dose–response analysis. There was evidence of non‐linear associations for intakes of fruit (pnon‐linearity<0.001) and vegetables (pnon‐linearity=0.041). There was no evidence of publication bias. These data support the hypothesis that intakes of vegetables and fruit may significantly reduce the risk of ESCC. Further investigation with prospective designs, validated questionnaires and good control of important confounders is warranted.
Identification of TDRD1 as a direct target gene of ERG in primary prostate cancer
Authors: Boormans Joost L. , Korsten Hanneke , Ziel‐van der Made Angelique J.C. , van Leenders Geert J.L.H. , de Vos Carola V. , Jenster Guido , Trapman Jan
Published: January 2013

Molecular classification of ERG‐rearranged prostate cancer clarifies the role of TMPRSS2‐ERG in the development and progression of prostate cancer. The objective of our study was to identify direct ERG target genes in ERG‐rearranged prostate cancer. Two independent cohorts of primary prostate cancer (Cohort A, n=48; Cohort B, n=31), a cohort of late‐stage prostate cancer (n=51) and expression array data of a cohort of primary prostate tumors from a different institute (n=128) were analyzed for expression of genes that were coexpressed with ERG overexpression. By genome‐wide expression analysis and Q‐RT‐PCR it was shown that the gene Tudor domain containing 1 (TDRD1) was by far the strongest correlated gene with ERG overexpression in both Cohort A and B. Expression array analysis of the patient cohort from a different institute showed a large overlap in genes that were positively correlated with ERG overexpression, including TDRD1. In late‐stage prostate cancer, TDRD1 was also coexpressed with ERG overexpression, although a proportion of ERG‐negative late‐stage samples expressed TDRD1. TDRD1 expression was not associated with ETV1 overexpression. In the prostate cancer cell line VCaP, downregulation of ERG by shRNA lead to a lower expression level of TDRD1 and resulted in a decreased activity of the TDRD1 promoter. By mutation analysis we identified a functional ERG binding site in the TDRD1 promoter. Our findings show TDRD1 as the first identified upregulated direct ERG target gene that is strongly associated with ERG overexpression in primary prostate cancer.
Country of origin, age at migration and risk of cutaneous melanoma: A migrant cohort study of 1,100,000 Israeli men
Authors: Levine Hagai , Afek Arnon , Shamiss Ari , Derazne Estela , Tzur Dorit , Astman Nadav , Keinan‐Boker Lital , Mimouni Daniel , Kark Jeremy D.
Published: January 2013

Cutaneous melanoma (CM) is a common cancer with increasing incidence in many parts of the world where light‐skinned populations live. We conducted a large‐scale nationally representative migrant cohort study to assess country of origin and age at migration as predictors of CM, controlling for possible confounders. Data on 1,086,569 Israeli Jewish males, who underwent a general health examination before compulsory military service at ages 16–19 between the years 1967–2005, were linked to Israel National Cancer Registry to obtain incident CM up to 2006. Cox proportional hazards was used to model time to event. Overall, 1562 incident cases were detected during 19.3 million person‐years of follow‐up. Origin was a strong independent predictor of CM. Incidence was higher for European (hazard ratio [HR] = 4.08, 95% confidence interval [CI]: 3.55–4.67) and Israeli origin (HR = 2.92, 95% CI: 2.25–3.79) compared to N. African/Asian origin, adjusted for year of birth, years of education, residential socio‐economic position, rural residence and body surface area (or height). Among those of European origin, the adjusted risk was significantly lower for those who immigrated after the age of 10 years (HR = 0.58, 95% CI: 0.45–0.73) but not for younger ages (HR = 1.02, 95% CI 0.84–1.23) compared to Israeli born. The high rates of CM among men of European origin and the almost twofold lower risk among those immigrating after age 10 provide solid support for the deleterious role of childhood sun exposure as a risk factor for melanoma. These findings will serve in directing public health and research efforts.
Morning types are less sensitive to pain than evening types all day long
Authors: Jankowski K.S.
Published: January 2013

Background

Diurnal variations in pain have been observed in experimental protocols, post‐surgery states and pathological conditions. Chronotype is considered to have the most profound effect on diurnal variations, and in addition, previous studies suggest that evening types may be more vulnerable to pain than morning types. This study aimed to examine whether or not morning and evening chronotypes differ in terms of their daily levels and diurnal fluctuations of pain sensitivity.

Methods

A total of 16 morning‐healthy and 15 evening‐healthy men were selected using the Morningness‐Eveningness Questionnaire and underwent nine measurements during 1 day (between 08:15 and 20:15 h), each consisting of five heat stimuli situated at the ventral side of the wrist.

Results

A marked difference between chronotypes was found, with morning types showing less sensitivity to pain than evening types all day long [M = 50.1; standard error (SE) = 1 and M = 47.2; SE = 1, respectively; pain thresholds in centigrade]. Diurnal variations in pain were not statistically significant.

Conclusions

The results showed that chronotype could be an important factor determining sensitivity to pain, regardless of time of day.
Effects of antiresorptive therapies on glucose metabolism: Results from the FIT, HORIZON-PFT, and FREEDOM trials
Authors: Schwartz Ann V , Schafer Anne L , Grey Andrew , Vittinghoff Eric , Palermo Lisa , Lui Li-Yung L , Wallace Robert B , Cummings Steven R , Black Dennis M , Bauer Douglas C , Reid Ian R
Published: January 2013

In rodent models, undercarboxylated osteocalcin (ucOC) acts as a hormone that promotes insulin sensitivity and secretion. If ucOC plays a similar role in humans, then antiresorptive therapies, which reduce ucOC levels, may increase the risk of insulin resistance and diabetes. We tested whether antiresorptive therapies result in higher fasting glucose, increased weight, or greater diabetes incidence in post hoc analyses of three randomized, placebo-controlled trials in postmenopausal women: Fracture Intervention Trial (FIT) (N = 6151) of alendronate (4 years), Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly Pivotal Fracture Trial (HORIZON-PFT) (N = 7113) of zoledronic acid (3 years), and Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) trial (N = 7076) of denosumab (3 years). Fasting glucose was measured annually in FIT and HORIZON in a subset of women, and every 6 months in FREEDOM in all participants. Weight was measured annually in all trials. Incident diabetes was identified from adverse event reports, initiation of diabetes medication, or elevated fasting glucose. Differences in fasting glucose changes from randomization to trial conclusion between treatment and placebo groups were not statistically significant: −0.47 mg/dL in FIT, 0.20 mg/dL in HORIZON-PFT, and 0.09 mg/dL in FREEDOM, all p > 0.6. Weight change differed between treatment and placebo groups in FIT (0.32 kg, p = 0.003) and FREEDOM (0.31 kg, p = 0.023) but not in HORIZON-PFT (0.15 kg, p = 0.132). In the three trials combined, diabetes occurred in 203 and 225 women assigned to treatment or placebo, respectively. Diabetes incidence was not increased in any of the treatment groups or in the pooled estimate (pooled relative risk [RR] = 0.90; 95% confidence interval [CI] 0.74–1.10). Antiresorptive therapy does not have a clinically important effect on fasting glucose, weight, or diabetes risk in postmenopausal women. Contrary to predictions from mouse models, reduced bone turnover does not appear to play a significant role in glucose metabolism in humans.
Juvenile Paget's disease in an Iranian kindred with vitamin D deficiency and novel homozygous TNFRSF11B mutation
Authors: Saki Forough , Karamizadeh Zohreh , Nasirabadi Shiva , Mumm Steven , McAlister William H , Whyte Michael P
Published: January 2013

Juvenile Paget's disease (JPD) is a rare heritable osteopathy characterized biochemically by markedly increased serum alkaline phosphatase (ALP) activity emanating from generalized acceleration of skeletal turnover. Affected infants and children typically suffer bone pain and fractures and deformities, become deaf, and have macrocranium. Some who survive to young adult life develop blindness from retinopathy engendered by vascular microcalcification. Most cases of JPD are caused by osteoprotegerin (OPG) deficiency due to homozygous loss-of-function mutations within the TNFRSF11B gene that encodes OPG. We report a 3-year-old Iranian girl with JPD and craniosynostosis who had vitamin D deficiency in infancy. She presented with fractures during the first year-of-life followed by bone deformities, delayed development, failure-to-thrive, and pneumonias. At 1 year-of-age, biochemical studies of serum revealed marked hyperphosphatasemia together with low-normal calcium and low inorganic phosphate and 25-hydroxyvitamin D levels. Several family members in previous generations of this consanguineous kindred may also have had JPD and vitamin D deficiency. Mutation analysis showed homozygosity for a unique missense change (c.130T>C, p.Cys44Arg) in TNFRSF11B that would compromise the cysteine-rich domain of OPG that binds receptor activator of NF-κB ligand (RANKL). Both parents were heterozygous for this mutation. The patient's serum OPG level was extremely low and RANKL level markedly elevated. She responded well to rapid oral vitamin D repletion followed by pamidronate treatment given intravenously. Our patient is the first Iranian reported with JPD. Her novel mutation in TNFRSF11B plus vitamin D deficiency in infancy was associated with severe JPD uniquely complicated by craniosynostosis. Pamidronate treatment with vitamin D sufficiency can be effective therapy for the skeletal disease caused by the OPG deficiency form of JPD.
High‐order absorbing boundary conditions for the meshless radial point interpolation method in the frequency domain
Authors: Kaufmann Thomas , Engström Christian
Published: January 2013

The meshless radial point interpolation method (RPIM) in frequency domain for electromagnetic scattering problems is presented. This method promises high accuracy in a simple collocation approach using radial basis functions. The treatment of high‐order non‐reflecting boundary conditions for open waveguides is discussed and implemented up to fourth‐order. RPIM allows the direct calculation of high‐order spatial derivatives without the introduction of auxiliary variables. High‐order absorbing boundary conditions offer a choice of absorbing angles for each degree of spatial derivatives. For general applications, a set of these absorbing angles is calculated using global optimization. Numerical experiments show that at the same computational cost, the numerical reflections of the absorbing boundary conditions are much lower than conventional perfectly matched layers, especially at high angles of incidence. Copyright © 2013 John Wiley & Sons, Ltd.
Switching of hydrogen bonds of water in ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate
Authors: Yoshimura Yukihiro , Takekiyo Takahiro , Okamoto Chikara , Hatano Naohiro , Abe Hiroshi
Published: January 2013

We have investigated temperature‐induced Raman spectral changes of deuterated water in an ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim][BF4]), between room temperature and 77 K. The comparison of the OH and OD stretching vibrational spectra at 77 K shows that the strength of the hydrogen bonds in [bmim][BF4]–water mixtures strongly depends on the type of water, i.e. H2O and D2O. In the [bmim][BF4]–D2O system, remarkably strong hydrogen bonds form at low temperatures, but they switch to nearly free hydrogen bonds on heating. Copyright © 2013 John Wiley & Sons, Ltd.
Estimation of the breakthrough volume of selected steroids for C‐18 solid‐phase extraction sorbent using retention data from micro‐thin layer chromatography
Authors: Bielicka‐Daszkiewicz Katarzyna , Voelkel Adam , Rusińska‐Roszak Danuta , Zarzycki Paweł K.
Published: January 2013

SPE method is a very popular technique, and is commonly used for the prepurification, concentration, and isolation of different organic compounds from variable matrices. In this work, the optimization of SPE process was carried out. The breakthrough volume of solid sorbents based on octadecylsilane was determined and three methods were compared: (1) calculation one – the breakthrough volume was calculated using retention factor k determined with micro‐TLC method, frontal analysis – (2) breakthrough volume was determined as volume of whole elution peak, and (3) breakthrough volume was determined as the center of peak gravity. For calculation method, the k values of key estrogens and progestogens were derived from the micro‐TLC experiment reported previously. By combining these three methods, we can point the start of elution, the maximum concentration of analyte in eluate, and the whole eluent volume, which is necessary to achieve an appropriate selectivity and high extraction recovery. Proposed calculation method allows to estimate the beginning of the steroid peak, when the analyte appears in the eluate flowing from the sorbent. Such observation advances the SPE optimization protocol that was described before and was based on the correlation between raw kSPE and kmicro‐TLC data.
Aero‐elastic bearing effects on rotor dynamics: a numerical analysis
Authors: Barzem L. , Bou‐Said B. , Rocchi J. , Grau G.
Published: January 2013

In recent decades, numerous models for airfoil bearings have been developed. However, these models are not sufficiently accurate for rotor response prediction in the presence of nonlinearities. It is essential to control the instabilities due to the nonlinear behaviour in order to quantify the energy dissipation in the bearings. By means of a variational approach, the flexible structure is modelled as a thin medium subject to a compressible fluid pressure, under isothermal conditions, in the laminar and turbulent regimes. The model is constructed using the finite element method for the structure response. Internal dry friction is taken into account with Coulomb's law and an updated Lagrangian method. The structure model is coupled with Reynolds equation to obtain the rotor displacement, using the equations of motion for the complete mechanical system.

This work is performed to show the influence of the thin structure approach on the rotor behaviour and the field pressure. The link between deflection of the bumps and dry friction is established. The structure buckling is increased by both friction between the sheets and energy dissipation. A second objective is to identify the subsynchronous frequencies in order to establish the relevance of the new airfoil model for nonlinear and instability investigations. Copyright © 2012 John Wiley & Sons, Ltd.
Chloride intracellular channel 4 involves in the reduced invasiveness of cancer cells treated by photodynamic therapy
Authors: Chiang Pei‐Chi , Chou Ruey‐Hwang , Chien Hsiung‐Fei , Tsai Tsuimin , Chen Chin‐Tin
Published: January 2013

Background and Objectives

The mechanisms of photodynamic therapy (PDT) have been studied on the cellular and tissue levels. However, the cellular behaviors of cancer cells survived from PDT are still not clear. Previously, we have found that PDT‐derived variants A375/3A5 and A375/6A5 have reduced invasion ability. This study attempted to further elucidate the possible molecules associated with the altered invasiveness in the PDT‐derived variants and cancer cells treated with PDT.

Study Design/Materials and Methods

Scratch wound healing assay and invasion assay were performed to evaluate the migration and invasion ability of human A375 melanoma and MDA‐MB‐231 breast adenocarcinoma cells. Single colony selection and microarray analysis were performed to examine the differentially expressed transcripts in parental A375 and PDT‐derived variants. RT‐PCR and Western blots analysis were performed to examine the expression levels of matrix metalloproteinase 9 (MMP9) and chloride intracellular channel 4 (CLIC4). The MMP9 activity was examined by Zymography assay. CLIC4 expressing construct was used to examine the influence on MMP9 expression and invasion ability of cancer cells treated with PDT.

Results

Correlated with the reduced invasiveness, we found that A375/3A5 and A375/6A5 cells have decreased production of MMP9. Microarray analysis and RT‐PCR showed CLIC4 was down‐regulated in the PDT‐derived variants. Furthermore, down‐regulation of CLIC4 and MMP9 was found in cancer cells treated with PDT. Transfection of surviving cancer cells with a plasmid vector encoding CLIC4 increased MMP9 expression and cell invasion. Furthermore, overexpression of CLIC4 in A375 and MDA‐MB‐231 cancer cells constrains PDT‐induced suppression of invasiveness.

Conclusion

Our results showed that the reduced expression of CLIC4 could further down‐regulate MMP9 and result in the suppression of invasion in cancer cells treated with PDT. These results provide an insight into a new mechanism by which PDT affects the metastatic potential of cancer cells through down‐regulation of MMP9 by CLIC4. Lasers Surg. Med. 45: 38–47, 2013. © 2013 Wiley Periodicals, Inc.
Nanostructured Films of Block Copolymers Functionalized With Photolabile Protected Amino Groups
Authors: Stadermann Jan , Riedel Maria , Voit Brigitte
Published: January 2013

Two phase separating block copolymers with photolabile protected amino groups in one block have been synthesized through RAFT polymerization followed by efficient click modification. Techniques like NMR, GPC, and DSC were applied for the characterization of these functional materials. The block copolymers were used for the preparation of thin films where they assemble to form distinct nanostructures as detected by AFM analysis.
New Water‐Soluble Cationic Poly(p‐phenylenevinylene) Derivative: the Interaction with DNA and Selective Fluorescence Enhancement Induced by ssDNA
Authors: Zhang Wenjun , Xu Li , Qin Jingui , Yang Chuluo
Published: January 2013

A new cationic cyano‐substituted poly(p‐phenylenevinylene) (N‐CNPPV) is synthesized by Knoevenagel condensation. The water‐soluble polymer shows different emission spectra in different solvents and displays unique fluorescent behaviors in the mixed solvents of water and THF. The new polymer can form a complex with ssDNA by adopting a more planar conformation, exhibiting red shift of emission wavelength and enhancement of fluorescence intensity. By investigating the fluorescent response of N‐CNPPV to various surfactants, we demonstrate that the hydrophobic interaction and electrostatic interaction result in the selective response of N‐CNPPV to ssDNA. This is the first report on selective fluorescence enhancement of conjugated polyelectrolyte induced by ssDNA.
A New Disubstituted Polyacetylene Bearing 6‐Benzylaminopurine Moieties: Postfunctional Synthetic Strategy and Sensitive Chemosensor Towards Copper and Cobalt Ions
Authors: Ou Daxin , Zhang Liang , Huang Yanfen , Lou Xiaoding , Qin Jingui , Li Zhen
Published: January 2013

A new 6‐benzylaminopurine‐functionalized disubstituted polyacetylene (P2) with strong green fluorescence is successfully synthesized by utilizing the postfunctional method. The polymer is soluble in common organic solvents, and its strong green fluorescence can be quenched by copper and cobalt ions with a detection limit down to 1.0 × 10−8 (0.64 ppb) and 3.3 × 10−8 mol L−1 (1.94 ppb), respectively. Moreover, not much interference is observed from other metal ions, including Li+, Na+, K+, Fe3+, Fe2+, Ni2+, Hg2+, Mg2+, Al3+, Zn2+, Mn2+, Pb2+, Ba2+, Ca2+, Cd2+, Ag+, and Cr3+. Furthermore, P2 can be put into application using test strips, making P2 a practical, sensitive, and selective copper and cobalt probe.

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Longitudinal 1H MRS of rat forebrain from infancy to adulthood reveals adolescence as a distinctive phase of neurometabolite development
Authors: Morgan Jonathan J. , Kleven Gale A. , Tulbert Christina D. , Olson John , Horita David A. , Ronca April E.
Published: January 2013

This study represents the first longitudinal, within‐subject 1H MRS investigation of the developing rat brain spanning infancy, adolescence and early adulthood. We obtained neurometabolite profiles from a voxel located in a central location of the forebrain, centered on the striatum, with smaller contributions for the cortex, thalamus and hypothalamus, on postnatal days 7, 35 and 60. Water‐scaled metabolite signals were corrected for T1 effects and quantified using the automated processing software LCModel, yielding molal concentrations. Our findings indicate age‐related concentration changes in N‐acetylaspartate + N‐acetylaspartylglutamate, myo‐inositol, glutamate + glutamine, taurine, creatine + phosphocreatine and glycerophosphocholine + phosphocholine. Using a repeated measures design and analysis, we identified significant neurodevelopment changes across all three developmental ages and identified adolescence as a distinctive phase in normative neurometabolic brain development. Between postnatal days 35 and 60, changes were observed in the concentrations of N‐acetylaspartate + N‐acetylaspartylglutamate, glutamate + glutamine and glycerophosphocholine + phosphocholine. Our data replicate past studies of early neurometabolite development and, for the first time, link maturational profiles in the same subjects across infancy, adolescence and adulthood. Copyright © 2013 John Wiley & Sons, Ltd.
Encapsulants for light‐emitting diodes from visible light‐cured epoxy monomers
Authors: Schroeder Walter F. , dell´Erba Ignacio E. , Arenas Gustavo F. , Asmussen Silvana V. , Vallo Claudia I.
Published: January 2013

During the last decade, light‐emitting diodes (LEDs) have replaced incandescent, fluorescent, and neon lamps due to their ability to produce high luminosity at low currents and voltages. LEDs are currently encapsulated by thermally curable epoxy resins. However, long periods of curing at high temperature result in high consumption of energy and require stringent process control to avoid failure of the devices. In addition, the thermal cure results in yellowing of the encapsulant, which decreases the efficiency of the LED. In recent years, photoinitiated polymerization has received much interest as it congregates a wide range of economic and ecological benefits. Cationic photoinitiators, such as diaryliodonium salts, generate Brønsted acid in situ, which initiates polymerization. The process can be triggered on demand by irradiating the mixture with light. Results from the present research reveal that cycloaliphatic epoxy monomers, photoactivated with an iodonium salt and Camphorquinone, polymerize readily under visible light irradiation (470 nm) in the absence of external heating. The partial replacement of cycloaliphatic epoxy with aromatic diglycidyl ether of bisphenol‐A (DGEBA) is an effective means of improving the refractive index of the material and consequently the efficiency of the photoemission. Visible light polymerization of DGEBA pure proceeds at a slow rate; however, it is enhanced by the increase in temperature during the polymerization of the highly reactive cycloaliphatic monomer. From results obtained in the present research, it may be concluded that visible light polymerization of epoxy monomers is a promising route for the processing of LED encapsulants. Copyright © 2013 John Wiley & Sons, Ltd.
Ultrahigh molecular weight polyethylene fibers prepared using conical dies with varying dimensions
Authors: Yeh Jen‐Taut , Wang Chuen‐Kai , Zhou Qin , Zhou Huo‐Peng , Tsai Chih‐Chen , Lai Yu‐Ching , Tsou Chi‐Hui , Chen Kan‐Nan , Huang Chi‐Yuan , Lee Kuei‐Chi
Published: January 2013

Dimensions of conical dies were found to have a significant influence on thermal, morphological, orientation, ultradrawing, and dynamic mechanical properties of the as‐prepared and/or drawn ultrahigh molecular weight polyethylene (UHMWPE) fiber specimens prepared in this study. Many demarcated “micro‐fibrils” were found paralleling to fiber direction of the as‐prepared UHMWPE fiber specimens. The percentage crystallinity, melting temperatures, orientation factor (fo) and achievable draw ratio (Dra) values of each as‐prepared UHMWPE fiber specimen prepared at a fixed length of outlet land reach a maximum value, as the entry angles of the conical die approach the optimum value at 75°. The maximum fo and Dra values obtained for each F2075‐y as‐prepared fiber series specimens prepared using the optimum entry angle reach another maximum value as their length of outlet land approach the optimum value of 6.5 mm. The ultimate tensile strengths and moduli of the drawn UHMWPE fibers prepared at the optimum entry angle and length of outlet land are significantly higher than those of fibers prepared at other conditions but stretched to the same draw ratio. Possible reasons accounting for the above interesting properties were discussed in this study. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers
A stochastic approach for continuous and discontinuous crack growth in polycarbonate under cyclic loading
Authors: Matsuda Shinya , Ogi Keiji
Published: January 2013

This article presents a stochastic approach to predict fatigue crack propagation (FCP) diagrams of continuous crack growth (CCG) and discontinuous crack growth (DCG) in polycarbonate (PC) under cyclic loading. First, it is assumed that the macroscopic fatigue crack propagates stochastically. The transition probability is then expressed in conjunction with the craze fibril breakdown model for CCG. Second, the stochastic process is applied to DCG assuming that DCG occurs because of an unstable crack growth in the craze zone. A fracture criterion using a stress intensity factor is introduced for the unstable crack growth. As a result, we obtain an FCP diagram where the rate in CCG is lower than that in DCG. The stress intensity factor range for the DCG–CCG transition can be theoretically determined. Finally, to verify the present approach, the experimental data of DCG and CCG of PC are fitted to the Paris equation. In addition, the relationship between the DCG band size and the number of cycles required for DCG is predicted in order to compare it with the experiment data. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers
Modification of Enamel and Dentin Surfaces by Non‐Thermal Atmospheric Plasma
Authors: Lehmann Antje , Rueppell André , Schindler Axel , Zylla Isabella‐Maria , Seifert Hans Jürgen , Nothdurft Frank , Hannig Matthias , Rupf Stefan
Published: January 2013

Tooth material surface chemical and micromechanical properties are important for success and sustainability in restorative dentistry. Modification by cold atmospheric plasma jet treatment may help to improve presently existing shortcomings as a part of future restorative therapies. The present study has been focused on changes of surface properties of tooth substances by this approach. Polished and etched enamel and dentin slices from the vestibular face of bovine incisors are used. A plasma jet modifies these surfaces at a distance of 2 mm and with a scan velocity of 5.5 mm · s−1. The treatment parameters are: helium process gas flow 3.525 slm, plasma excitation by 2.45 GHz with an average pulsed microwave power of 2 W, single pulse power of 250 W, pulse width 5 µs. The surface modifications are subjected to laser scanning microscope roughness‐measurement, contact angle measurements, X‐ray photoelectron spectroscopy (XPS) analysis and morphological visualization by scanning electron microscopy (SEM). Plasma treatment causes changes of surface roughness and morphological alterations on dentin, while no such changes are measureable on etched dentin and polished and etched enamel surfaces. Plasma causes contact angle reductions for both, water and ethylene glycol. XPS analyses show significant carbon reduction on enamel surfaces after plasma treatment. Admixture of 30% of hydrogen peroxide or deionized water, respectively, as precursors in the plasma jet processing gas flow generates measureable amounts of CO‐bindings at the surfaces assigned to hydrophilic groups. Surface modifications by plasma treatment might enable interesting new options for dental procedures in all areas of interaction between tooth substance and restorative materials.

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Identification of a novel ligand binding site in phosphoserine phosphatase from the hyperthermophilic archaeon Thermococcus onnurineus
Authors: Jung Tae‐Yang , Kim Yae‐Sel , Oh Byoung‐Ha , Woo Euijeon
Published: January 2013

Phosphoserine phosphatase (PSP) catalyzes the final and irreversible step of L‐serine synthesis by hydrolyzing phosphoserine to produce L‐serine and inorganic phosphate. Developing a therapeutic drug that interferes with serine production is of great interest to regulate the pathogenicity of some bacteria and control D‐serine levels in neurological diseases. We determined the crystal structure of PSP from the hyperthermophilic archaeon Thermococcus onnurineus at 1.8 Å resolution, revealing an NDSB ligand bound to a novel site that is located in a fissure between the catalytic domain and the CAP module. The structure shows a half‐open conformation of the CAP 1 module with a unique protruding loop of residues 150–155 that possesses a helical conformation in other structures of homologous PSPs. Activity assays indicate that the enzyme exhibits marginal PSP activity at low temperature but a sharp increase in the kcat/KM value, approximately 22 fold, when the temperature is increased. Structural and biochemical analyses suggest that the protruding loop in the active site might be an essential component for the regulation of the activity of PSP from hyperthermophilic T. onnurineus. Identification of this novel binding site distantly located from the catalytic site may be exploited for the development of effective therapeutic allosteric inhibitors against PSP activity. © Proteins 2013. © 2012 Wiley Periodicals, Inc.
Assessment of 3D models for allergen research
Authors: Power Trevor D. , Ivanciuc Ovidiu , Schein Catherine H. , Braun Werner
Published: January 2013

Allergenic proteins must crosslink specific IgE molecules, bound to the surface of mast cells and basophils, to stimulate an immune response. A structural understanding of the allergen–IgE interface is needed to predict cross‐reactivities between allergens and to design hypoallergenic proteins. However, there are less than 90 experimentally determined structures available for the approximately 1500 sequences of allergens and isoallergens cataloged in the Structural Database of Allergenic Proteins. To provide reliable structural data for the remaining proteins, we previously produced more than 500 3D models using an automated procedure, with strict controls on template choice and model quality evaluation. Here, we assessed how well the fold and residue surface exposure of 10 of these models correlated with recently published experimental 3D structures determined by X‐ray crystallography or NMR. We also discuss the impact of intrinsically disordered regions on the structural comparison and epitope prediction. Overall, for seven allergens with sequence identities to the original templates higher than 27%, the backbone root‐mean square deviations were less than 2 Å between the models and the subsequently determined experimental structures for the ordered regions. Further, the surface exposure of the known IgE epitopes on the models of three major allergens, from peanut (Ara h 1), latex (Hev b 2), and soy (Gly m 4), was very similar to the experimentally determined structures. For the three remaining allergens with lower sequence identities to the modeling templates, the 3D folds were correctly identified. However, the accuracy of those models is not sufficient for a reliable epitope mapping. © Proteins 2013. © 2012 Wiley Periodicals, Inc.
Enhanced polarization switching in ferroelectric Bi0.5Na0.5TiO3 single crystals by defect control
Authors: Yanai Ken , Kitanaka Yuuki , Noguchi Yuji , Miyayama Masaru , Moriyoshi Chikako , Kuroiwa Yoshihiro , Kurushima Kousuke , Mori Shigeo
Published: January 2013

Single crystals of ferroelectric (Bi,Na)TiO3 (BNT) were grown by the top‐seeded solution growth (TSSG) method at a high oxygen pressure of 0.9 MPa using Pt crucibles and their conductivity (leakage current) and polarization properties were investigated at 25 °C along 〈100〉cubic. The platinum concentration ([Pt]) in BNT crystals was controlled by using different kinds of Na salts in flux. It is shown that the conductivity of BNT crystals is governed by Bi vacancies for crystals with a [Pt] less than approximately 4000 ppm and by Pt impurities for ones with a higher [Pt].

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Photo and polarization hysteresis of a high‐quality (Bi,Na)TiO3 ferroelectric single crystal. Enhanced polarization switching (a large remanent polarization and a low coercive field) was achieved by defect control during the crystal growth.
Néel order and the destruction of localized magnetic moments in the crossover from the Mott–Heisenberg to the Slater limit
Authors: Kopeć T. K. , Zaleski T. A.
Published: January 2013

We study the antiferromagnetic phase of the three‐dimensional (3D) Hubbard model with nearest‐neighbor hopping on a bipartite cubic lattice. We use the quantum SU(2) × U(1) rotor approach that yields a fully self‐consistent treatment of the antiferromagnetic state that respects the symmetry properties of the model and satisfies the Mermin–Wagner theorem. As our theory describes the evolution from a Slater (U ≪ t) to a Mott–Heisenberg (U ≫ t) antiferromagnet, we present the phase diagram of the antiferromagnetic Hubbard model as a function of the crossover parameter U/t.
Specific features of sublimation growth of bulk AlN crystals on SiC wafers
Authors: Mokhov E. , Izmaylova I. , Kazarova O. , Wolfson A. , Nagalyuk S. , Litvin D. , Vasiliev A. , Helava H. , Makarov Yu.
Published: January 2013

The features of 2” AlN bulk crystal growth by the sublimation sandwich method (SSM) on SiC seeds in a graphite‐heated reactor are investigated. AlN growth conditions and crystal properties are compared with the results of SiC sublimation growth in the same reactor. The specifics of AlN sublimation growth, including insufficient reproducibility of results, are believed to be caused by the low sticking coefficient of molecular nitrogen and the high reactivity of Al vapors. The formation of pores in the AlN crystal is explained by selective sublimation etching of the growing surface. The negative effect of non‐optimal growth conditions and impurities on AlN crystal quality is discussed. The analysis of container materials, inert to Al vapors was carried out. Various types of TaC crucibles suitable for growth of bulk AlN crystals on SiC seeds were developed. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Spatial‐EWMA Framework for Detecting Clustering
Authors: Lin Chen‐ju , Tsui Kwok‐Leung , Lin Chen‐yu
Published: January 2013

Spatial surveillance is critical to health systems, manufacturing industries, and in many other domains. For example, determining hotspots of infectious diseases and detecting defect patterns on semiconductor wafers require sensitive spatial analysis tools. The goal of this paper is to detect spatial clusters with mean shifts. Conventional multivariate analysis methods may ignore spatial structure among data and lead to inefficient inspection. Several likelihood ratio‐based scan statistics have been designed for spatial surveillance. However, there is no most powerful test when parameters like shift magnitude and coverage are unknown. This paper proposes a spatial exponentially weighted moving average (spatial‐EWMA) approach that can detect the existence and locate the potential centers of shift clusters. The test procedure assigns different weights to the data with different radius levels from the investigated shift center. The efficiency of the spatial‐EWMA approach is shown by simulation. Lastly, an example of detecting the counties with high incidence of male thyroid cancer in New Mexico is provided to show the effectiveness of the proposed approach. Copyright © 2013 John Wiley & Sons, Ltd.
Chemical labeling of electrochemically cleaved peptides
Authors: Roeser Julien , Alting Niels F. A. , Permentier Hjalmar P. , Bruins Andries P. , Bischoff Rainer P. H.
Published: January 2013

RATIONALE

Cleavage of peptide bonds C‐terminal to tyrosine and tryptophan after electrochemical oxidation may become a complementary approach to chemical and enzymatic cleavage. A chemical labeling approach specifically targeting reactive cleavage products is presented here and constitutes a promising first step towards the development of a new proteomics workflow.

METHODS

Hexylamine was used to react with the spirolactone moieties generated after electrochemical oxidation and cleavage of tripeptides. The influence of pH and reaction time on the yield was determined and the excess of tagging reagent was optimized. Selective detection of the tagged cleavage products was achieved by precursor ion scanning in a triple quadrupole mass spectrometer.

RESULTS

Optimal labeling was reached under aqueous conditions when working at pH 10 with a reaction time of 0.5 min. The excess of hexylamine over spirolactone groups can be significantly decreased by working under non‐aqueous conditions in pure acetonitrile to prevent spirolactone hydrolysis. The specific formation of hexylamine‐containing y1 reporter ions generated by collision‐induced dissociation (CID) tandem mass spectrometry (MS/MS) allows for selective detection by precursor ion scanning of the cleaved and labeled peptides.

CONCLUSIONS

This work presents a method for selective labeling and detection of electrochemically cleaved Tyr‐ and Trp‐containing peptides for which reaction conditions have been optimized with hexylamine as labeling agent. This workflow offers new possibilities for electrochemical oxidation, cleavage and labeling of peptides and proteins. Copyright © 2013 John Wiley & Sons, Ltd.