bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear, Edge‐Sharing Heterometallic Trinuclear [CoII–LnIII–CoII] (LnIII = GdIII, DyIII, TbIII, and HoIII) Complexes: Slow Relaxation of Magnetization in the DyIII Derivative
Authors: Chandrasekhar Vadapalli , Das Sourav , Dey Atanu , Hossain Sakiat , Kundu Subrata , Colacio Enrique 
Published: November 2013

AbstractThe sequential reaction of a multisite coordination ligand (LH4) with lanthanide (III) nitrates followed by the addition of Co(NO3)2·6H2O in a 4:1:2 ratio in the presence of triethylamine afforded a series of heterometallic, linear trinuclear complexes [Co2Ln(LH3)4]·3NO3 [Ln = DyIII (1), GdIII (2), TbIII (3), and HoIII (4)]. These tricationic complexes contain nitrate counteranions. The cationic portion of these complexes consists of three metal ions that are arranged in a linear fashion; a central LnIII is present between the two terminal CoII ions and is attached to the latter through two phenoxide bridging groups. This arrangement generates two contiguous four‐membered CoLnO2 rings. The CoII ions are six‐coordinate (2N, 4O) in a distorted octahedral geometry, whereas the central lanthanide ion is eight‐coordinate (8O) in a distorted square‐antiprismatic geometry. Magnetic studies of these complexes have been performed and indicate a slow relaxation of the magnetization for the DyIII derivative 1.
Extending the Family of N‐Heterocyclic Heavy Carbene Analogues: Synthesis and Crystal and Molecular Structures of MeN[CH2C(O)N(R)]2Sn (R = Me2NCH2CH2, PhCH2, Me3CCH2)
Authors: Iovkova‐Berends Ljuba , Seiger Miriam , Westfeld Thomas , Hoffmann Alexander , Herres‐Pawlis Sonja , Jurkschat Klaus 
Published: November 2013

AbstractInvited for the cover of this issue is the group of Klaus Jurkschat at Technische Universität Dortmund. The cover image shows cyclic diazastannylenes reported by Hahn et al., Russel et al., Zaitsev et al., and Jurkschat et al., which have intramolecular donor→Sn coordination in common.
Synthesis and Comparative Study of Homoisofagomines and Analogues as Glycosidase Inhibitors
Authors: Basak Ranjan Kumar , Vankar Yashwant D. 
Published: November 2013

AbstractThe synthesis of polyhydroxyazepanes and their corresponding lactams has been carried out by use of Grubbs cyclisation, to yield the azepane scaffolds, as a key step. A comparative study of glycosidase inhibition by the azepanes and the corresponding lactams with varying stereochemical dispositions, number of hydroxy groups, and side chain structures was carried out.
Chemoenzymatic Synthesis of Enantiomerically Pure syn‐Configured 1‐Aryl‐3‐methylisochroman Derivatives
Authors: Simon Robert C. , Busto Eduardo , Richter Nina , Belaj Ferdinand , Kroutil Wolfgang 
Published: November 2013

AbstractA two‐step synthesis of various enantiomerically pure 1‐aryl‐3‐methylisochroman derivatives was accomplished through asymmetric biocatalytic ketone reduction followed by an oxa‐Pictet–Spengler reaction. The compounds were obtained in good to excellent yield (47–92 %) in favor of the syn diastereomers [dr (syn/anti) up to 99:1]. Enantiopure arylpropanols serving as pronucleophiles for the C–C bond‐formation step were obtained by biocatalytic reduction by employing enantiocomplementary alcohol dehydrogenases, which gave access to the (S) and (R) enantiomer with up to >99 % conversion and up to >99 % ee.
Simple Electrodeposition of Dendritic Pd Without Supporting Electrolyte and Its Electrocatalytic Activity Toward Oxygen Reduction and H2O2 Sensing
Authors: Kang Minkyung , Yang Yejin , Shim Jun Ho , Lee Sang Cheol , Lee Youngmi , Lee Chongmok 
Published: November 2013

AbstractMetallic palladium (Pd) electrocatalysts for oxygen reduction and hydrogen peroxide (H2O2) oxidation/reduction are prepared via electroplating on a gold metal substrate from dilute (5 to 50 mM) aqueous K2PdCl4 solution. The best Pd catalyst layer possessing dendritic nanostructures is formed on the Au substrate surface from 50 mM Pd precursor solution (denoted as Pd‐50) without any additional salt, acid or Pd templating chemical species. The Pd‐50 consisted of nanostructured dendrites of polycrystalline Pd metal and micropores within the dendrites which provide high catalyst surface area and further facilitate reactant mass transport to the catalyst surface. The electrocatalytic activity of Pd‐50 proved to be better than that of a commercial Pt (Pt/C) in terms of lower overpotential for the onset and half‐wave potentials and a greater number of electrons (n) transferred. Furthermore, amperometric i–t curves of Pd‐50 for H2O2 electrochemical reaction show high sensitivities (822.2 and −851.9 µA mM−1 cm−2) and low detection limits (1.1 and 7.91 µM) based on H2O2 oxidation H2O2 reduction, respectively, along with a fast response (<1 s).
Speciation analysis of lead in marine animals by using capillary electrophoresis couple online with inductively coupled plasma mass spectrometry
Authors: Chen Yiquan , Huang Limei , Wu Weihua , Ruan Yajuan , Wu Zujian , Xue Zhimin , Fu FengFu 
Published: November 2013

We herein reported a environment‐friendly microwave‐assisted extraction used to extract trace lead compounds from marine animals and a ultrasensitive method for the analysis of Pb2+, trimethyl lead chloride (TML) and triethyl lead chloride (TEL) by using CE‐ICP‐MS. The extraction method is simple and has a high extracting efficiency. It can be used to completely extract both inorganic lead and organolead in marine animal samples without altering its species. The analytical method has a detection limit as low as 0.012–0.084 ng Pb/mL for Pb2+, TML, and TEL, and can be used to determine ultratrace Pb2+, TML, and TEL in marine animals directly without any preconcentration. With the help of above methods, we have successfully determined Pb2+, TML, and TEL in clam and oyster tissue within 20 min with a RSD (n = 6) < 5% and a recovery of 91–104%. Our results showed that Pb2+ was the main species of lead in clam and oyster, and organolead (TML) was only found in oyster. The proposed method provides a realistic approach for the accurate evaluation of lead pollution in seafood.
Exceptionally strong sorption of infochemicals to activated carbon reduces their bioavailability to fish
Authors: Jonker Michiel T.O. , van Mourik Louise 
Published: November 2013

Abstract

The addition of activated carbon (AC) to sediments is a relatively new approach to remediate contaminated sites. Activated carbon strongly sorbs hydrophobic organic contaminants, thereby reducing their bioavailability and uptake in organisms. Because of its high sorption capacity, AC might, however, also sorb other chemicals that are not contaminants but instead have ecological functions. Examples of such compounds are infochemicals or pheromones (i.e., compounds serving as chemical inter- and intraspecies information vectors). The present study investigated the sorption of 2 known infochemicals, hypoxanthine-3-N-oxide (H3NO) and pyridine-N-oxide (PNO), to 5 different powdered ACs. Sorption isotherms of these low-molecular-weight, polar fish kairomone substances appeared highly nonlinear, with logarithmic Freundlich sorption coefficients of up to 7.6. At physiologically relevant concentrations, sorption was up to 7 to 9 orders of magnitude stronger than expected on the basis of hydrophobic forces only (i.e., the compounds' log octanol–water partition coefficient, being approximately –1), indicating exceptionally strong binding to specific sites. This binding effectively reduced the bioavailability of H3NO to Sarasa goldfish, as was shown in a behavioral assay. The present study demonstrates the previously unrecognized potential of AC to sorb ecologically relevant chemicals. Whether this potential may lead to subtle, unwanted ecological effects in the field will have to be investigated in more detail during future research. Environ Toxicol Chem 2014;33:493–499. © 2013 SETAC
Biological responses of marine flatfish exposed to municipal wastewater effluent
Authors: Vidal-Dorsch Doris E. , Bay Steven M. , Greenstein Darrin J. , Baker Michael E. , Hardiman Gary , Reyes Jesus A. , Kelley Kevin M. , Schlenk Daniel 
Published: November 2013

Abstract

There is increasing concern over the presence of pharmaceutical compounds, personal care products, and other chemicals collectively known as contaminants of emerging concern (CECs) in municipal effluents, yet knowledge of potential environmental impacts related to these compounds is still limited. The present study used laboratory exposures to examine estrogenic, androgenic, and thyroid-related endocrine responses in marine hornyhead turbot (Pleuronichthys verticalis) exposed to CECs from municipal effluents with 2 degrees of treatment. Fish were exposed for 14 d to environmentally realistic concentrations of effluent (0.5%) and to a higher concentration (5%) to investigate dose responses. Plasma concentrations of estradiol (E2), vitellogenin (VTG), 11-keto testosterone, and thyroxine were measured to assess endocrine responses. Contaminants of emerging concern were analyzed to characterize the effluents. Diverse types of effluent CECs were detected. Statistically significant responses were not observed in fish exposed to environmentally realistic concentrations of effluent. Elevated plasma E2 concentrations were observed in males exposed to ammonia concentrations similar to those found in effluents. However, exposure to ammonia did not induce VTG production in male fish. The results of the present study highlight the importance of conducting research with sentinel organisms in laboratory studies to understand the environmental significance of the presence of CECs in aquatic systems. Environ Toxicol Chem 2014;33:583–591. © 2013 SETAC
The vas::egfp transgenic zebrafish: A practical model for studies on the molecular mechanisms by which environmental estrogens affect gonadal sex differentiation
Authors: Filby Amy L. , Ortiz-Zarragoitia Maren , Tyler Charles R. 
Published: November 2013

Abstract

The vas::egfp transgenic zebrafish (Danio rerio) could significantly enhance studies on the mechanisms by which environmental estrogens disrupt sexual differentiation, because the developing gonad can be visualized during early life via fluorescence detection. There are methodological challenges regarding dissecting out the gonads in early-life-stage fish, however, and transgene responses to estrogen exposure have not been tested. The authors exposed vas::egfp transgenic zebrafish and their wild-type siblings to the model estrogen 17α-ethinylestradiol (EE2; 0.62 ng/L and 3.33 ng/L measured concentrations) during sexual development (20−60 d posthatch) and used enhanced green fluorescent protein (egfp) fluorescence to identify and dissect single gonads (at 40 d posthatch) to provide sufficient RNA for individual gene expression analyses, retaining the remaining gonad in the body cavity for histological analyses of sex and stage of development. Genotyping confirmed that all transgenic control fish were phenotypically egfp positive (showed green fluorescence). Interestingly, however, in a few transgenic fish exposed to EE2, no phenotypic egfp signal was seen, most notably for the 3.33 ng/L EE2 exposure. It was subsequently found that gonadal vasa expression was reduced by this concentration of EE2. Hepatic vitellogenin expression demonstrated that the vas::egfp and wild-type lines responded to estrogen with an equivalent sensitivity. The authors conclude that the vas::egfp zebrafish provides an enhanced and practical system for mechanistic studies on the effects of environmentally relevant concentrations of estrogens on gonad development. Environ Toxicol Chem 2014;33:602–605. © 2013 SETAC
Electrochemical Test Procedures for Accelerated Evaluation of Fuel Cell Cathode Catalyst Degradation
Authors: Marcu A. , Toth G. , Behm R. J. 
Published: November 2013

AbstractThe paper introduces an accelerated test procedure that was developed to evaluate the cathode catalyst stability. It is based on systematic analysis of square wave cycles (SWC) in comparison to triangular wave cycles (TWC). Two voltage windows were used: (i) 0.6–0.9 V to simulate the fuel cell drive cycles and (ii) 0.6–1.2 V to accelerate the test. When simulating the drive cycles over 6,000 h, an estimated loss of 40% in electrochemical surface area (ECSA) is found. Increasing the potential window, the testing time could be reduced to 20 h for TWC and for SWC to 4 h.
Hybrid Network Sulfonated Polynorbornene/Silica Membranes with Enhanced Proton Conductivity by Doped Phosphotungstic Acid
Authors: He X.‐H. , Zheng Y. , Yao H.‐L. , Chen Y.‐W. , Chen D.‐F. 
Published: November 2013

AbstractA series of novel hybrid sulfonated polynorbornene‐silica (PBN–SiO2) proton conducting membranes doped with different weight ratio of phosphotungstic acid (PWA) were prepared by the casting procedure. The proton conductivity of the composite membranes containing 40 wt.% PWA reached the maximum of 6.1 × 10–2 S cm–1 and increased gradually with PWA content and temperature elevating, while the methanol permeabilities (3.52–9.39 × 10–7 cm2 s–1) of these membranes were much lower than that of Nafion 117 (2.36 × 10–6 cm2 s–1). The membranes also exhibited excellent thermally stable and mechanical properties, which imply that the PBN–SiO2–PWA membranes are promising materials in the direct methanol fuel cells (DMFC) applications.
Detecting Rare Haplotype‐Environment Interaction With Logistic Bayesian LASSO
Authors: Biswas Swati , Xia Shuang , Lin Shili 
Published: November 2013

ABSTRACTTwo important contributors to missing heritability are believed to be rare variants and gene‐environment interaction (GXE). Thus, detecting GXE where G is a rare haplotype variant (rHTV) is a pressing problem. Haplotype analysis is usually the natural second step to follow up on a genomic region that is implicated to be associated through single nucleotide variants (SNV) analysis. Further, rHTV can tag associated rare SNV and provide greater power to detect them than popular collapsing methods. Recently we proposed Logistic Bayesian LASSO (LBL) for detecting rHTV association with case–control data. LBL shrinks the unassociated (especially common) haplotypes toward zero so that an associated rHTV can be identified with greater power. Here, we incorporate environmental factors and their interactions with haplotypes in LBL. As LBL is based on retrospective likelihood, this extension is not trivial. We model the joint distribution of haplotypes and covariates given the case–control status. We apply the approach (LBL‐GXE) to the Michigan, Mayo, AREDS, Pennsylvania Cohort Study on Age‐related Macular Degeneration (AMD). LBL‐GXE detects interaction of a specific rHTV in CFH gene with smoking. To the best of our knowledge, this is the first time in the AMD literature that an interaction of smoking with a specific (rather than pooled) rHTV has been implicated. We also carry out simulations and find that LBL‐GXE has reasonably good powers for detecting interactions with rHTV while keeping the type I error rates well controlled. Thus, we conclude that LBL‐GXE is a useful tool for uncovering missing heritability.
Tissue-Level Mechanisms Responsible for the Increase in Bone Formation and Bone Volume by Sclerostin Antibody
Authors: Ominsky Michael S , Niu Qing-Tian , Li Chaoyang , Li Xiaodong , Ke Hua Zhu 
Published: November 2013

ABSTRACT

Bone formation can be remodeling-based (RBF) or modeling-based (MBF), the former coupled to bone resorption and the latter occurring directly on quiescent surfaces. Unlike osteoanabolic therapies such as parathyroid hormone (PTH) 1-34 that increase bone remodeling and thus both formation and resorption, sclerostin antibody (Scl-Ab) increases bone formation while decreasing bone resorption. With this unique profile, we tested our hypothesis that Scl-Ab primarily elicited MBF by examining bones from Scl-Ab–treated ovariectomized (OVX) rats and male cynomolgus monkeys (cynos). Histomorphometry was performed to quantify and characterize bone surfaces in OVX rats administered vehicle or Scl-Ab (25 mg/kg) subcutaneously (sc) twice/week for 5 weeks and in adolescent cynos administered vehicle or Scl-Ab (30 mg/kg) sc every 2 weeks for 10 weeks. Fluorochrome-labeled surfaces in L2 vertebra and femur endocortex (cynos only) were considered to be MBF or RBF based on characteristics of their associated cement lines. In OVX rats, Scl-Ab increased MBF by eightfold (from 7% to 63% of bone surface, compared to vehicle). In cynos, Scl-Ab markedly increased MBF on trabecular (from 0.6% to 34%) and endocortical surfaces (from 7% to 77%) relative to vehicle. Scl-Ab did not significantly affect RBF in rats or cynos despite decreased resorption surface in both species. In cynos, Scl-Ab resulted in a greater proportion of RBF and MBF containing sequential labels from week 2, indicating an increase in the lifespan of the formative site. This extended formation period was associated with robust increases in the percent of new bone volume formed. These results demonstrate that Scl-Ab increased bone volume by increasing MBF and prolonged the formation period at both modeling and remodeling sites while reducing bone resorption. Through these unique effects on bone formation and resorption, Scl-Ab may prove to be an effective therapeutic to rapidly increase bone mass in diseases such as osteoporosis. © 2014 American Society for Bone and Mineral Research.
Carbon Aerogels Supported Pt Nanoparticles as Electrocatalysts for Methanol Oxidation in Alkaline Media
Authors: Liu Yong , Wei Min , Qu Jianying , Mao Liqun 
Published: November 2013

AbstractCarbon aerogels (CAs) were prepared by sol‐gel polycondensation of resorcinol and formaldehyde with BET surface area of 616 m2 g−1 and the average pore size of 9.8 nm. The prepared CAs were used as supports for Pt nanoparticles for methanol oxidation in alkaline media. In comparison with Pt supported on commercial Vulcan XC‐72R carbon (Pt/C) electrocatalysts, Pt supported on CAs (Pt/CAs) electrocatalysts exhibited higher peak current density and more negative onset potential toward methanol oxidation. The effects of different parameters such as NaOH concentration, methanol concentration, and scan rate on the methanol oxidation reaction were investigated in detail. The results showed that the Pt/CAs electrocatalysts had promising application for methanol oxidation in alkaline media.
T1 Mapping using variable flip angle SPGR data with flip angle correction
Authors: Liberman Gilad , Louzoun Yoram , Ben Bashat Dafna 
Published: November 2013

PurposeTo improve the calculation of T1 relaxation time from a set of variable flip‐angle (FA) spoiled gradient recalled echo images.Materials and MethodsThe proposed method: (a) uses a uniform weighting of all FAs, (b) takes into account global inaccuracies in the generation of the prescribed FAs by estimating the actual FAs, and (c) incorporates data‐driven local B1 inhomogeneity corrections. The method was validated and its accuracy tested using simulated data, phantom, and in vivo experiments. Results were compared with existing analysis methods and to inversion recovery (IR). Consistency was assessed by means of repeated scans of two subjects. Reference values were obtained from eight healthy subjects from various brain regions and compared with literature values.ResultsThe method accurately and consistently estimated T1 values in all cases. The method was more robust, in comparison with the standard method, to the choice of FA set; to inaccuracies in generation of the prescribed FAs (in simulated data, T1 estimation error was 12.1 ms versus 235.5 ms); demonstrated greater consistency (in vivo study showed interscan T1 difference of 80 ms versus 356 ms); and achieved a better agreement with IR on phantom (median absolute difference of 123.8 ms versus 790 ms). Reference T1 values were 883/801 ms for female/male in white matter and 1501/1349 ms in gray matter, within the range previously reported.ConclusionThe proposed method overcomes some inaccuracies in FA production, providing more accurate estimation of T1 values compared with standard methods, and is applicable for currently available data. J. Magn. Reson. Imaging 2014;40:171–180. © 2013 Wiley Periodicals, Inc.
Comparing average breast fat content results from two different protocols at 1.5T and 3T: Can the data be pooled?
Authors: Chavez Sofia , Stanisz Greg 
Published: November 2013

PurposeTo compare the total breast fat content computed from two separate studies, performed on different scanners and with different protocols, with the goal of defining a relationship to allow pooling the data.Materials and MethodsTwelve healthy volunteer women were scanned with two different protocols on the same day. The protocols differed in four important aspects: vendors (GE vs. Philips), scanner main magnetic field strengths (1.5T vs. 3T), pulse sequences (2D fast spin‐echo vs. 3D spoiled gradient‐echo), and water/fat separation techniques. The resulting water and fat maps were processed with in‐house software to extract breast tissue slice‐wise. Percent fat content was calculated for each breast, per subject.ResultsTotal percent fat contents (averaged across both breasts) resulting from both protocols were plotted against each other, on a subject‐by‐subject basis, revealing a strong correlation (R2 > 0.99), with an overestimation of the fat content from Protocol 1 relative to Protocol 2. The proposed T2 TE‐correction for Protocol 1 improves the correlation while decreasing the discrepancy between protocols.ConclusionTotal breast fat content of healthy women resulting from the two protocols can be pooled using a linear relationship. The proposed T2 TE‐corrected Protocol 1 is expected to yield accurate fat content. J. Magn. Reson. Imaging 2014;40:890–898. © 2013 Wiley Periodicals, Inc.
Assessing liver fibrosis: Comparison of arterial enhancement fraction and diffusion‐weighted imaging
Authors: Bonekamp David , Bonekamp Susanne , Ou Hsin‐You , Torbenson Michael S. , Corona‐Villalobos Celia Pamela , Mezey Esteban , Kamel Ihab R. 
Published: November 2013

PurposeNoninvasive markers have been developed to reduce the need for liver biopsy. The aim of this study was to compare the strength of association of the arterial enhancement fraction (AEF), apparent diffusion coefficient (ADC), and serum biomarkers for staging hepatic fibrosis.Materials and MethodsEighty‐five patients with chronic liver disease underwent triple‐phase contrast‐enhanced MRI, used to calculate AEF, and diffusion‐weighted MRI (b = 0,750 s/mm2), used to calculate ADC. Hepatic fibrosis was staged according METAVIR criteria. The overall association of the four biomarkers (AEF, ADC, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio, and aspartate aminotransferase to platelet ratio index [APRI]) was compared using nonparametric tests and receiver operating characteristic (ROC) curve, using histopathologic analysis as the reference standard.ResultsAEF and ADC values differed significantly between histopathologic fibrosis stages. AEF values correlated with fibrosis stage, ADC values correlated negatively with fibrosis stage. Compared with ADC, AEF showed a trend toward an improved capability of discriminating fibrosis stages. A weighted composite score of AEF and ADC had significantly better diagnostic accuracy than ADC alone (P ≤ 0.023). Imaging parameters had a significantly better diagnostic accuracy than AST/ALT ratio or APRI.ConclusionAEF may be able to detect the presence of mild, moderate, and advanced liver fibrosis, and its value is increased with concomitant use of ADC.J. Magn. Reson. Imaging 2014;40:1137–1146. © 2013 Wiley Periodicals, Inc.