bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supramolecular Nanofibers/Hydrogels of the Conjugates of Nucleobase, Saccharide, and Amino Acids
Authors: Wu Dongdong , Du Xuewen , Shi Junfeng , Zhou Jie , Xu Bing 
Published: April 2014

AbstractThree new hydrogelators based on the conjugates of three naturally occurring biological building blocks: nucleobase, saccharide, and amino acids, were explored. Being synthesized via a facile solid phase peptide synthesis route, the hydrogelators self‐assemble in water to afford supramolecular nanofibers and hydrogels. Transmission electron microscopy, oscillation rheometry, and circular dichroism reveal that the hydrogels consist of largely helix‐based nanofibers of the widths of 5–12 nm and exhibit storage moduli up to 1 kPa. These hydrogelators also exhibit excellent cell‐compatibility. This work illustrates a new platform for constructing molecular soft materials for nanobiotechnology.
Computational Investigations about the Effects of Hetero‐molecular Aggregation on Bioactivities: a Case of Neonicotinoids and Water
Authors: Xia Shuang , Cheng Jiagao , Feng Yue , Shao Xusheng , Luo Haibin , Xu Zhiping , Xu Xiaoyong , Li Zhong 
Published: April 2014

AbstractMolecular aggregation state of bioactive compounds plays a key role in bio‐interactive procedure. Diverse aggregation states of bioactive compounds contribute to different biological or chemical properties. Water‐bridge, as the simple hetero‐molecular aggregation, has been found bridging the binding between many bioactive compounds and their targets through hydrogen bonding network, e.g. in the recognition of neonicotinoids with insect nAChRs. To better understanding the roles of water‐bridge on bioactivities of compounds, an approach of hetero‐dimeric aggregation with water was proposed. Quantitative structure‐activity relationship (QSAR) and pharmacophore modeling investigations were applied on 19 neonicotinoids, as well as their aggregates with water. The aggregate‐based CoMSIA, PHASE and linear QSAR models presented better statistical significance and predictabilities than the monomer ones, which indicated that the bioactivities correlated with the aggregate properties and water bridged hydrogen bond of the active site. All results revealed the essential roles of water‐bridge in ligand recognition, which should be considered in future ligand design and optimization.
Preparation of Durable Emitter of Electrospray Mass Spectrometry by Covalently Coating the Fused‐Silica Capillary Tip with Carbon‐Nanotube Sol‐Gel Composite Material
Authors: Zhang Hanzhi , Liu Chao , Zhang Xuepei , Kang Jingwu 
Published: April 2014

AbstractA simple approach for the preparation of emitter of electrospray ionization mass spectrometry by covalently coating the fused‐silica capillary tip with the conductive carbon‐nanotube sol‐gel composite material (CNTSCM) is described. The CNTSCM was prepared by dispersing single‐walled carbon nanotubes in the sol composed of a mixture of 3‐glycidoxypropyltrimethoxysilane and 3‐aminopropyltrimethoxysilane, and ethanol. The long‐term stability of the prepared ESI emitters was demonstrated by at least 180 h of continuous use. Signal intensity obtained by the prepared emitter was mass‐flux sensitive when the flow rate was lower than 500 nL/min, while the signal intensity performed a concentration dependence when the flow rate was in the range of 500–800 nL/min. The usefulness of such a prepared emitter was demonstrated by the analysis of various types of samples such as organic small molecular drugs, oligosaccharide, peptide, and protein.
New Soluble Near‐Infrared Dyes Based on Terrylene Diimides with Four Aromatic Heterocycles
Authors: Wei Huimin , Jiang Nan , Zhao Nan , Zhang Ying , Gao Baoxiang 
Published: April 2014

AbstractTerrylene diimides with four aromatic heterocycles (AHTDIs) were synthesized under Stille Cross‐coupling conditions and fully characterized by NMR and mass spectrometry. The aggregation of the terrylene diimide (TDI) was suppressed by four heterocycles substituents on the bay region, and these AHTDIs exhibited good solubility in common organic solvents. The effects of the substituted groups on the optical and electrochemical properties were also investigated. The introduction of four aromatic heterocycles on the bay of TDI resulted in significant red‐shifts of the absorption peak (100 nm), corresponding to a decrease in the band gap from 1.82 to 1.50 eV. Furthermore, with four rich electron aromatic heterocycles, the AHTDIs showed 280 mV negative‐shifts of first oxidation potentials and a new oxidation wave, corresponding to an increase in the HOMO levels from?−5.60 to?−5.28 eV.
Recent Improvement in Coronary Computed Tomography Angiography Diagnostic Accuracy
Authors: Alani Anas , Nakanishi Rine , Budoff Matthew J. 
Published: April 2014

ABSTRACTAlthough invasive coronary angiography has been the gold standard for evaluating coronary artery disease (CAD), it should not be routinely performed as an initial test to assess CAD in subjects with suspected CAD by the recent guidelines, due to cost, invasiveness, and measurable risk. Coronary computed tomography angiography (CCTA) is a rapidly growing, noninvasive imaging modality that developed quickly over the last decade, and its role for evaluation of CAD becomes of great promise with high diagnostic accuracy. Although artifact issues have created some challenges for CCTA, recent advances—including the introduction of more detectors, leading to broader coverage, and faster and higher‐definition scanners—allow improved precision and fewer uninterpretable studies. This review article summarizes the current key literature regarding the diagnostic accuracy of CCTA in native coronary arteries, stents, coronary artery bypass grafts, lesions with high calcification, and the functional assessment of CAD.
Insight into the Recognition, Binding, and Reactivity of Catalytic Metallodrugs Targeting Stem Loop IIb of Hepatitis C IRES RNA
Authors: Bradford Seth S. , Ross Martin James , Fidai Insiya , Cowan James A. 
Published: April 2014

AbstractThe complex Cu‐GGHYrFK‐amide (1‐Cu) was previously reported as a novel metallotherapeutic that catalytically inactivates stem loop IIb (SLIIb) of the hepatitis C virus (HCV) internal ribosomal entry site (IRES) RNA and demonstrates significant antiviral activity in a cellular HCV replicon assay. Herein we describe additional studies focused on understanding the cleavage mechanism as well as the relationship of catalyst configuration to structural recognition and site‐selective cleavage of the structured RNA motif. These are advanced by use of a combination of MALDI‐TOF mass spectrometry, melting temperature determinations, and computational analysis to develop a structural model for binding and reactivity toward SLIIb of the IRES RNA. In addition, the binding, reactivity, and structural chemistry of the all‐D‐amino acid form of this metallopeptide, complex 2‐Cu, are reported and compared with those of complex 1‐Cu. In vitro RNA binding and cleavage assays for complex 2‐Cu show a KD value of 76±3 nM, and Michaelis–Menten parameters of kcat=0.14±0.01 min−1 and KM=7.9±1.2 μM, with a turnover number exceeding 40. In a luciferase‐based cellular replicon assay Cu‐GGhyrfk‐amide shows activity similar to that of the 1‐Cu parent peptide, with an IC50 value of 1.9±0.4 μM and cytotoxicity exceeding 100 μM. RT‐PCR experiments confirm a significant decrease in HCV RNA levels in replicon assays for up to nine days when treated with complex 1‐Cu in three‐day dosing increments. This study shows the influence that the α‐carbon stereocenter has for this new class of compounds, while detailed mass spectrometry and computational analyses provide new insight into the mechanisms of recognition, binding, and reactivity.
Color naming experiments using 2D and 3D rendered samples
Authors: Tanaka Midori , Horiuchi Takahiko , Tominaga Shoji 
Published: April 2014

AbstractThis article describes a color naming experiment using 2D and 3D rendered color samples. Conventional color naming experiments using a priori clues generally involve 2D clues such as color patches. However, in real‐world scenes, most objects have 3D shapes whose colors are affected by illumination effects such as shadows and gloss. We use 2D and 3D rendered samples as clues in the experiments, and analyze the relationship between color terms and object surfaces. First, we develop a color term collection system that can produce 218 test colors. We render the color images of a flat disk as a 2D sample and a sphere as a 3D sample on a calibrated display device. It is supposed that the 2D and 3D surfaces with the same object color are obtained under the same conditions of viewing and illumination. The results of color naming experiments show that there are differences for color terms between 2D and 3D samples. Important findings are as follows: (1) brighter color terms tend to be chosen for the 3D samples than the 2D samples, when observing achromatic colors, (2) achromatic color terms are chosen for 3D samples having low saturation, and (3) for chromatic colors, a darker color term is generally chosen in comparison to the corresponding 2D samples of the same color. These properties become more prominent by changing the illumination angle from 0° to 45° to the surface normal. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 270–280, 2015
Relating annual increments of the endangered Blanding's turtle plastron growth to climate
Authors: Richard Monik G. , Laroque Colin P. , Herman Thomas B. 
Published: April 2014

AbstractThis research is the first published study to report a relationship between climate variables and plastron growth increments of turtles, in this case the endangered Nova Scotia Blanding's turtle (Emydoidea blandingii). We used techniques and software common to the discipline of dendrochronology to successfully cross‐date our growth increment data series, to detrend and average our series of 80 immature Blanding's turtles into one common chronology, and to seek correlations between the chronology and environmental temperature and precipitation variables. Our cross‐dated chronology had a series intercorrelation of 0.441 (above 99% confidence interval), an average mean sensitivity of 0.293, and an average unfiltered autocorrelation of 0.377. Our master chronology represented increments from 1975 to 2007 (33 years), with index values ranging from a low of 0.688 in 2006 to a high of 1.303 in 1977. Univariate climate response function analysis on mean monthly air temperature and precipitation values revealed a positive correlation with the previous year's May temperature and current year's August temperature; a negative correlation with the previous year's October temperature; and no significant correlation with precipitation. These techniques for determining growth increment response to environmental variables should be applicable to other turtle species and merit further exploration.
The influence of antecedent floods on aquatic invertebrate diversity, abundance and community composition
Authors: Greenwood M. J. , Booker D. J. 
Published: April 2014

AbstractAnthropogenic alterations to flow regimes have been identified as a serious threat to river ecology. Such alterations can affect the magnitude and timing of high and low flows. It is therefore important to understand how antecedent flow conditions affect aquatic communities. However, few studies have investigated whether antecedent flow conditions cause common, generalizable and perhaps predictable changes in aquatic invertebrate communities across a range of rivers. Using 22 years of data from 66 river sites in New Zealand, we investigated (1) whether there were common relationships between the time since a recent flood and aquatic invertebrate communities within a site and (2) whether site differences in hydrology or physical habitat could explain the rate and direction of community changes. Aquatic invertebrate diversity, abundance and several aspects of community composition changed significantly with time since a flood. The rate and direction of these changes varied markedly between sites, but was at least partly explained by differences in site characteristics related to hydrological regime, physical habitat, land use and network location. Results suggested that alterations to hydrological regimes that change flood frequency will affect aquatic invertebrate diversity, abundance and community composition in many rivers. It may be possible to use site or hydrological regime characteristics to identify rivers in which aquatic invertebrate communities are more likely to change, and perhaps the direction of change. Our results also highlight the importance of accounting for recent floods in sampling programmes that compare water quality or ecosystem health over time within a site. Copyright © 2014 John Wiley & Sons, Ltd.
A Planar Decanuclear Cobalt(II) Phosphonate
Authors: Sahoo Dipankar , Metre Ramesh K. , Kroener Wolfgang , Gieb Klaus , Müller Paul , Chandrasekhar Vadapalli 
Published: April 2014

AbstractA decanuclear cobalt(II) phosphonate, [Co10{2,3,5,6‐(Me)4C6HCH2PO3}8{2,3,5,6‐(Me)4C6HCH2PO3H}4Cl6]·6Et3NH·10n‐hexane·16H2O (1) with a planar arrangement of the CoII ions is described. This compound shows slow relaxation of its dynamic magnetization.
Synthesis, Characterization, and Cytotoxic Activity of AuI N,S‐Heterocyclic Carbenes Derived from Peptides Containing L‐Thiazolylalanine
Authors: Gutiérrez Alejandro , Gimeno M. Concepción , Marzo Isabel , Metzler‐Nolte Nils 
Published: April 2014

AbstractThiazolium salts 2a–b derived from a dipeptide Boc‐Gly‐(Thz‐Ala)‐OMe (1b) containing the nonproteinogenic amino acid L‐thiazolylalanine (Thz‐Ala) can be used to generate the corresponding N,S‐heterocyclic carbene (NSHC) gold(I) (3a–b) and silver(I) (4) complexes. Reaction of the NSHC‐gold(I) iodide 3b with Boc‐Cys‐Gly‐OMe gives access to the peptide bioconjugate 5, which contains a NSHC‐Au‐(S‐Cys) unit. Compounds 3–5 constitute the first coin metal NSHC‐peptide complexes. All new compounds were comprehensively characterized by 1H, 13C and 2D‐NMR spectroscopy, IR spectroscopy, and mass spectrometry. Their cytotoxicity was studied in vitro against three different tumor cell lines (A549, Jurkat T and MiaPaca2) and IC50 values in the low micromolar range (< 25 μM), and as low as 0.4 μM in the best case were observed. All new Au complexes show good stability and promising properties and, as a result, this novel type of gold(I) carbene complex opens possibilities for the design of new metal‐based drugs with promising antitumor characteristics.
Efficient Domino Synthesis of Pyrrole‐Fused Isocoumarins with Microwave Heating
Authors: Sun Mu‐Yan , Meng Xiao‐Yan , Zhao Fu‐Jie , Dang Yi‐Jing , Jiang Fei , Liu Kai , Wang Cong‐Shuai , Jiang Bo , Tu Shu‐Jiang 
Published: April 2014

AbstractA new three‐component approach to polyfunctionalized isochromeno[4,3‐b]pyrroles has been developed with excellent regioselectivity. During these domino reactions, two ring‐opening and three cyclization reactions were readily achieved through carbon–carbon bond cleavage under transition‐metal‐free conditions. The advantages of atom and step economy, and scope make this reaction a powerful tool for assembling tri‐heterocyclic scaffolds of general chemical and biomedical interest.
Tributary confluences and discontinuities in channel form and sediment texture: Rio Chama, NM
Authors: Swanson Benjamin J. , Meyer Grant 
Published: April 2014

ABSTRACTNumerous morphological changes can occur where two channels of distinct sediment and flow regimes meet, including abrupt shifts in channel slope, cross‐sectional area, planform style, and bed sediment size along the receiving channel. Along the Rio Chama between El Vado and Abiquiu Dams, northern New Mexico, arroyo tributaries intermittently deliver sediment from erodible sandstone and shale canyon walls to the mainstem channel. Much of the tributary activity occurs in flash floods and debris flows during summer thunderstorms, which often load the channel with sand and deposit coarser material at the mainstem confluence. In contrast, mainstem channel flow is dominated by snowmelt runoff. To examine tributary controls, we systematically collected cross‐section elevation and bed sediment data upstream and downstream of 26 tributary confluences along a 17 km reach. Data from 203 cross‐sections were used to build a one‐dimensional hydraulic model for comparing estimated channel parameters at bankfull and low‐flow conditions at these sites As compared to intermediate reaches, confluences primarily impact gradient and bed sediment size, reducing both parameters upstream of confluences and increasing them downstream. Cross‐section area is also slightly elevated above tributary confluences and reduced below. Major shifts in slope and bed sediment size at confluences appear to drive variations in sediment entrainment and transport capacity and the relative storage of sand along the channel bed. The data were analyzed and compared to models of channel organization based on lateral inputs, such as the Network Variance Model and the Sediment Link Concept. At a larger scale, hillslope − channel coupling increases in the downstream third of the study reach, where the canyon narrows, resulting in steeper slopes and more continuous coarse bed material along the mainstem, and thus, limiting the contrast with tributary confluences. However, channel form and sediment characteristics are highly variable along the study reach, reflecting variations in the size and volume of sediment inputs related to the surface geology in tributary watersheds, morphology of the Rio Chama at the junction (i.e. bends, confinement), and the relative magnitude and location of past depositional events. Copyright © 2014 John Wiley & Sons, Ltd.
Application of bioassay panel for assessing the impact of advanced oxidation processes on the treatment of reverse osmosis brine
Authors: Justo Ana , González Óscar , Aceña Jaume , Mita Luigi , Casado Marta , Pérez Sandra , Piña Benjamín , Sans Carme , Barceló Damià , Esplugas Santiago 
Published: April 2014

AbstractBACKGROUNDThe persistence of microcontaminants through conventional wastewater treatments is a matter of concern and it suggests the implementation of advanced treatment steps. Although there is evidence that reverse osmosis (RO) is the most efficient treatment for the the removal of these compounds, it has the drawback of producing significant amounts of highly polluted brine. In this work, chemical analyses and toxicity bioassays were combined to evaluate the removal of different pharmaceuticals and of dioxin‐like compounds from RO brine through oxidative processes such as ozone, UV and UV/H2O2.RESULTSThe removal of the selected pharmaceuticals required a relatively high oxidative capacity, either by ozonation or by the combination of UV radiation and H2O2. Bioassays showed a significant dioxin‐like activity in brine samples, whereas antibacterial or estrogenic activities were negligible. UV by itself was the least efficient in removing this dioxin‐like activity. Ozonation appeared as the most competent treatment.CONCLUSIONSThe results of this work indicate the usefulness of advanced oxidation methods, especially ozonation, to remove biologically active micropollutants from brine samples. They also show that only the combination of chemical analyses and bioassays allows complete characterization of the efficiency of advanced water treatment processes to remove recalcitrant pollutants. © 2014 Society of Chemical Industry
Robust myocardial T2 and T2* mapping at 3T using image‐based shimming
Authors: Zaman Arshad , Higgins David M. , Motwani Manish , Kidambi Ananth , Kouwenhoven Marc , Kozerke Sebastian , Greenwood John P. , Plein Sven 
Published: April 2014

PurposeIntramyocardial hemorrhage and area at risk are both prognostic markers in acute myocardial infarction (AMI). Myocardial T2 and T2* mapping have been used to detect such tissue changes at 1.5T but these techniques are challenging at 3.0T due to additional susceptibility variation. We studied T2 and T2* myocardial mapping techniques at 3.0T on a system employing B1 shimming and compared two different methods of B0 shimming.Materials and MethodsFifteen volunteers and six AMI patients were scanned on a 3T system. Volume and image‐based (IB) B0 shimming techniques were implemented. Single breath‐hold, multiecho gradient, and spin echo sequences were employed from which T2* and T2 maps were calculated.ResultsIn volunteers, there was no significant difference in mean values obtained with volume or IB shimming for T2 mapping (39.1 ± 6.0 msec vs. 39.4 ± 6.1 msec; P > 0.05) or for T2* mapping (24.2 ± 6.7 msec vs. 24.1 ± 5.2 msec; P > 0.05). There were no significant regional differences in mean T2 values between septal, anterior, and posterior segments with either shimming technique (all P > 0.05); but there were significant regional differences in mean T2* values using volume shimming (27.8 ± 5.2 msec vs. 28.4 ± 5.8 msec vs. 15.9 ± 8.3 msec; P < 0.05)—but not with IB shimming (25.7 ± 5.4 msec vs. 25.3 ± 5.9 msec vs. 18.7 ± 4.6 msec; P > 0.05).ConclusionAt 3.0T, cardiac T2 mapping is robust. Although T2* mapping is prone to more regional heterogeneity this can be reduced by using IB instead of conventional volume B0 shimming. J. Magn. Reson. Imaging 2015;41:1013–1020. © 2014 Wiley Periodicals, Inc.
Bayesian Error Propagation for a Kinetic Model of n‐Propylbenzene Oxidation in a Shock Tube
Authors: Mosbach Sebastian , Hong Je Hyeong , Brownbridge George P. E. , Kraft Markus , Gudiyella Soumya , Brezinsky Kenneth 
Published: April 2014

ABSTRACTWe apply a Bayesian parameter estimation technique to a chemical kinetic mechanism for n‐propylbenzene oxidation in a shock tube to propagate errors in experimental data to errors in Arrhenius parameters and predicted species concentrations. We find that, to apply the methodology successfully, conventional optimization is required as a preliminary step. This is carried out in two stages: First, a quasi‐random global search using a Sobol low‐discrepancy sequence is conducted, followed by a local optimization by means of a hybrid gradient‐descent/Newton iteration method. The concentrations of 37 species at a variety of temperatures, pressures, and equivalence ratios are optimized against a total of 2378 experimental observations. We then apply the Bayesian methodology to study the influence of uncertainties in the experimental measurements on some of the Arrhenius parameters in the model as well as some of the predicted species concentrations. Markov chain Monte Carlo algorithms are employed to sample from the posterior probability densities, making use of polynomial surrogates of higher order fitted to the model responses. We conclude that the methodology provides a useful tool for the analysis of distributions of model parameters and responses, in particular their uncertainties and correlations. Limitations of the method are discussed. For example, we find that using second‐order response surfaces and assuming normal distributions for propagated errors is largely adequate, but not always.