bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of a new 2‐amino‐glycan, poly‐(1→6)‐α‐D‐mannosamine, by ring‐opening polymerization of 1,6‐anhydro‐mannosamine derivatives
Authors: Hattori Kazuyuki , Yoshida Takashi 
Published: August 2012

AbstractA stereoregular 2‐amino‐glycan composed of a mannosamine residue was prepared by ring‐opening polymerization of anhydro sugars. Two different monomers, 1,6‐anhydro‐2‐azido‐mannose derivative (3) and 1,6‐anhydro‐2‐(N, N‐dibenzylamino)‐mannose derivative (6), were synthesized and polymerized. Although 3 gave merely oligomers, 6 was promptly polymerized into high polymers of the number‐average molecular weight (Mn) of 2.3 × 104 to 2.9 × 104 with 1,6‐α stereoregularity. The differences of polymerizability of 3 and 6 from those of the corresponding glucose homologs were discussed. It was found that an N‐benzyl group is exceedingly suitable for protecting an amino group in the polymerization of anhydro sugars of a mannosamine type. The simultaneous removal of O‐ and N‐benzyl groups of the resulting polymers was achieved by using sodium in liquid ammonia to produce the first 2‐amino‐glycan, poly‐(1→6)‐α‐D‐mannosamine, having high molecular weight through ring‐opening polymerization of anhydro sugars.© 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Biocompatible poly(ethylene glycol)‐poly(γ‐cholesterol‐L‐glutamate) copolymers: Synthesis, characterization, and in vitro studies
Authors: Wu Yang , Ma Qing , Song Xiangrong , Zheng Yu , Ren Wen , Zhang Jinkun , Ouyang Liang , Wu Fengbo , He Gu 
Published: August 2012

AbstractA novel amphiphilic poly(ethylene glycol)‐block‐poly(γ‐cholesterol‐L‐glutamate) (mPEG–PCHLG) diblock copolymer has been synthesized. The mPEG–PCHLG copolymer has good biocompatibility and low toxicity. The mPEG–PCHLG copolymers could aggregate into nanoparticles with PCHLG blocks as the hydrophobic core and PEG blocks as the hydrophilic shell through emulsion solvent evaporation method. The copolymers were characterized by nuclear magnetic resonance spectroscopy, mass spectrum, Fourier transform infrared spectroscopy, and gel permeation chromatography. The particle sizes, size distributions, and zeta potentials of nanoparticles can also be determined by dynamic light scattering and transmission electron microscopy. This work provides a new and facile approach to prepare amphiphilic block copolymer nanoparticles with controllable performances. This novel copolymer may have potential applications in drug delivery and bioimaging applications.© 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Thermokarst Lakes on the Arctic Coastal Plain of Alaska: Spatial and Temporal Variability in Summer Water Temperature
Authors: Hinkel Kenneth M. , Lenters John D. , Sheng Yongwei , Lyons Evan A. , Beck Richard A. , Eisner Wendy R. , Maurer Eric F. , Wang Jida , Potter Brittany L. 
Published: August 2012

ABSTRACTIn summer 2010, water temperature profile measurements were made in 12 thermokarst lakes along a 150‐km long north–south transect across the Arctic Coastal Plain of northern Alaska. In shallow lakes, gradual warming of the water column to 1–4°C begins at the lake bed during decay of the ice cover in spring. Rapid warming follows ice‐off, with water temperature responding synchronously to synoptic weather variations across the area. Regionally, ice‐off occurs 2–4 weeks later on lakes near the coast. Inland lakes are warmer (13°C) in mid‐summer than those near the coast (7°C), reflecting the regional climate gradient and the maritime effect. All lakes are well mixed and largely isothermal, with some thermal stratification (< 2°C) occurring during calm, sunny periods in deeper lakes. In deep (6–9 m) lake‐bed depressions that are likely ice‐wedge troughs, water cools by conduction to the colder sediments below, while concurrent warming occurs in the upper water column. A spatially dense sample of near‐surface temperature measurements was collected from one lake over a short period and shows warmer (2–3°C) temperatures on the upwind, sheltered end of the lake. This study demonstrates that climatic gradients, meteorological conditions and basin characteristics impact lake temperature dynamics. Copyright © 2012 John Wiley & Sons, Ltd.
Virulence of Verticillium lecanii (Z.) against cereal aphids; does timing of infection affect the performance of parasitoids and predators?
Authors: Aqueel Muhammad A , Leather Simon R 
Published: August 2012

AbstractBACKGROUND: Entomopathogenic fungi such as Verticillium lecanii (Z.) (Mycotal®) are used for pest control as an alternative to chemical control. In this study, the effect of V. lecanii on cereal aphids is assessed. In addition, an investigation is carried out to determine whether the use of V. lecanii affects the performance of two natural enemies of aphids, the predator Harmonia axyridis (P.) and the parasitoid Aphidius colemani (V.), in no‐choice experiments under laboratory conditions.RESULTS: The number of Rhopalosiphum padi (L.) and Sitobion avenae (F.) killed was increased by increasing the concentration of V. lecanii. The timing of application of fungus to aphids affected the efficacy of other biocontrol agents, a parasitoid and a predator. Parasitation by A. colemani (V.) in both cereal aphids (S. avenae and R. padi) was not affected by V. lecanii when aphids were first treated with V. lecanii and then exposed to A. colemani. The emergence of adults from parasitised mummies was, however, lower in infected aphids than in uninfected aphids when the aphids were first exposed to the parasitoids and then treated with fungus. The female sex ratio in the emerging adults was lower in V. lecanii‐treated aphids in both species. When aphids were first treated with V. lecanii, 72 h before predation, fewer aphids of both species were consumed by H. axyridis (P.).CONCLUSION: Use of entomopathogenic fungus as a biological control agent could be a complementary strategy in an integrated pest management programme against cereal aphids, but it can reduce the efficiency of other biocontrol agents (parasitoids and predators) when applied simultaneously. © 2012 Society of Chemical Industry
Antibacterial activity of two chitosan solutions and their effect on rice bacterial leaf blight and leaf streak
Authors: Li Bin , Liu Baoping , Shan Changlin , Ibrahim Muhammad , Lou Yihan , Wang Yangli , Xie Guanlin , Li Hong‐ye , Sun Guochang 
Published: August 2012

AbstractBACKGROUND: Bacterial leaf blight and leaf streak are the two most damaging bacterial diseases of rice. However, few bactericidal chemicals are available for controlling both diseases. The antibacterial properties of two kinds of chitosan with different molecular weights and degrees of N‐deacetylation and their effect on rice bacterial leaf blight and leaf streak were evaluated.RESULTS: Results showed that the two kinds of chitosan solution possess a strong antibacterial activity against both rice bacterial pathogens and significantly reduced disease incidence and severity by comparison with the control under greenhouse conditions. However, the interaction between chitosan and rice pathogens was affected by the type and concentration of chitosan, the bacterial species and the contact time between chitosan and bacteria. The direct antibacterial activity of chitosan may be attributed to both membrane lysis and the destruction of biofilm. In addition, both chitosan solutions significantly increased the activities of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase in rice seedlings following inoculation of two rice pathogens by comparison with the control.CONCLUSION: The role of chitosan in protection of rice against bacterial pathogens has been shown to involve direct antibacterial activity and indirect induced resistance. Copyright © 2012 Society of Chemical Industry
Finite‐time formation control of multiple nonholonomic mobile robots
Authors: Ou Meiying , Du Haibo , Li Shihua 
Published: August 2012

SUMMARYThis paper considers finite‐time formation control problem for a group of nonholonomic mobile robots. The desired formation trajectory is represented by a virtual dynamic leader whose states are available to only a subset of the followers and the followers have only local interaction. First of all, a continuous distributed finite‐time observer is proposed for each follower to estimate the leader's states in a finite time. Then, a continuous distributed cooperative finite‐time tracking control law is designed for each mobile robot. Rigorous proof shows that the group of mobile robots converge to the desired geometric formation pattern in finite time. At the same time, all the robots can track the desired formation trajectory in finite time. Simulation example illustrates the effectiveness of our method. Copyright © 2012 John Wiley & Sons, Ltd.
Randomly coloring constant degree graphs
Authors: Dyer Martin , Frieze Alan , Hayes Thomas P. , Vigoda Eric 
Published: August 2012

AbstractWe study a simple Markov chain, known as the Glauber dynamics, for generating a random k ‐coloring of an n ‐vertex graph with maximum degree Δ. We prove that, for every ε > 0, the dynamics converges to a random coloring within O(nlog n) steps assuming k ≥ k0(ε) and either: (i) k/Δ > α* + ε where α*≈︁ 1.763 and the girth g ≥ 5, or (ii) k/Δ >β * + ε where β*≈︁ 1.489 and the girth g ≥ 7. Our work improves upon, and builds on, previous results which have similar restrictions on k/Δ and the minimum girth but also required Δ = Ω (log n). The best known result for general graphs is O(nlog n) mixing time when k/Δ > 2 and O(n2) mixing time when k/Δ > 11/6. Related results of Goldberg et al apply when k/Δ > α* for all Δ ≥ 3 on triangle‐free “neighborhood‐amenable” graphs.© 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013
Random doubly stochastic tridiagonal matrices
Authors: Diaconis Persi , Wood Philip Matchett 
Published: August 2012

AbstractLet
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\mathcal T}\end{align*} \end{document}n be the compact convex set of tridiagonal doubly stochastic matrices. These arise naturally in probability problems as birth and death chains with a uniform stationary distribution. We study ‘typical’ matrices T∈
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\mathcal T}\end{align*} \end{document}n chosen uniformly at random in the set
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\mathcal T}\end{align*} \end{document}n. A simple algorithm is presented to allow direct sampling from the uniform distribution on
\documentclass{article}\usepackage{mathrsfs}\usepackage{amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}{\mathcal T}\end{align*} \end{document}n. Using this algorithm, the elements above the diagonal in T are shown to form a Markov chain. For large n, the limiting Markov chain is reversible and explicitly diagonalizable with transformed Jacobi polynomials as eigenfunctions. These results are used to study the limiting behavior of such typical birth and death chains, including their eigenvalues and mixing times. The results on a uniform random tridiagonal doubly stochastic matrices are related to the distribution of alternating permutations chosen uniformly at random.© 2012 Wiley Periodicals, Inc. Random Struct. Alg., 42, 403–437, 2013
The disconfirmatory interview as a strategy for the assessment of system dynamics models
Authors: Andersen Deborah Lines , Luna‐Reyes Luis Felipe , Diker Vedat G. , Black Laura , Rich Eliot , Andersen David F. 
Published: August 2012

AbstractSystem dynamics requires the intense use of qualitative data and human judgment in all stages of model development. Most approaches to the formal inclusion of qualitative data have been employed with the purpose of knowledge elicitation during the conceptualization or formulation stages of modeling. In recent years, a small community of practice has explored the creation of interviewing tools to assess system dynamics models. We present the disconfirmatory assessment interview as a specific technique to be used during model assessment. This paper explores the use of interviews as a research and knowledge acquisition technique and more fully describes disconfirmatory assessment as an interview strategy. Based on a comparison of four applications of disconfirmatory interviews as a tool to assess system dynamics models, we present seven features that should form the core of the disconfirmatory interview. Copyright © 2012 System Dynamics Society.
Design and analysis of non‐pharmacological treatment trials with multiple therapists per patient
Authors: Roberts Chris , Walwyn Rebecca 
Published: August 2012

In trials of physical and talking therapies, nesting of patients within therapists has statistical implications analogous to those of cluster randomised trials. Nevertheless, the clustering effect may be more complex, as it interacts with treatment. For some therapies, individual patients may receive care from multiple therapists of the same type, so that patients are no longer strictly nested within therapists, creating a ‘multiple‐membership’ relationship between patients and therapists.This paper considers methods of analysis and sample size estimation for trials with multiple‐membership clustering effects. It is motivated by a trial of a psychotherapy for the treatment of adolescent depression with cognitive behavioural therapy. We tested methods and issues in a Monte Carlo simulation study, simulating trials with multiple membership. Results demonstrate satisfactory performance in terms of convergence and give estimates of the intra‐cluster correlation coefficient and empirical test size similar to a simple hierarchical design.We derive formulae for sample size and power for multiple‐membership trial designs. We then compare estimates of power from this formula with empirical power derived from the simulation study. Finally, we show that we can easily extend formulae for sample size and power to allow consideration of power and sample size for certain types of more complex interventions. These include situations where therapists of different types deliver separate components of the intervention, creating a cross‐classified relationship, or where several therapists deliver a group‐administered treatment, creating further levels. Copyright © 2012 John Wiley & Sons, Ltd.
Coating of Single DNA Molecules by Genetically Engineered Protein Diblock Copolymers
Authors: Hernandez‐Garcia Armando , Werten Marc W. T. , Stuart Martien Cohen , de Wolf Frits A. , de Vries Renko 
Published: August 2012

AbstractCoating DNA is an effective way to modulate its physical properties and interactions. Current chemosynthetic polymers form DNA aggregates with random size and shape. In this study, monodisperse protein diblock copolymers are produced at high yield in recombinant yeast. They carry a large hydrophilic colloidal block (≈400 amino acids) linked to a short binding block (≈12 basic amino acids). It is demonstrated that these protein polymers complex single DNA molecules as highly stable nanorods, reminiscent of cylindrical viruses. It is proposed that inter‐ and intramolecular bridging of DNA molecules are prevented completely by the small size of the binding block attached to the large colloidal stability block. These protein diblocks serve as a scaffold that can be tuned for application in DNA‐based nanotechnology.
Activation of Notch Signaling During Ex Vivo Expansion Maintains Donor Muscle Cell Engraftment
Authors: Parker Maura H. , Loretz Carol , Tyler Ashlee E. , Duddy William J. , Hall John K. , Olwin Bradley B. , Bernstein Irwin D. , Storb Rainer , Tapscott Stephen J. 
Published: August 2012

Abstract
Transplantation of myogenic stem cells possesses great potential for long-term repair of dystrophic muscle. However, a single donor muscle biopsy is unlikely to provide enough cells to effectively transplant the muscle mass of a patient affected by muscular dystrophy. Expansion of cells ex vivo using traditional culture techniques significantly reduces engraftment potential. We hypothesized that activation of Notch signaling during ex vivo expansion would maintain donor cell engraftment potential. In this study, we expanded freshly isolated canine muscle-derived cells on tissue culture plates coated with Delta-1ext-IgG to activate Notch signaling or with human IgG as a control. A model of canine-to-murine xenotransplantation was used to quantitatively compare canine muscle cell engraftment and determine whether engrafted donor cells could function as satellite cells in vivo. We show that Delta-1ext-IgG inhibited differentiation of canine muscle-derived cells and increased the level of genes normally expressed in myogenic precursors. Moreover, cells expanded on Delta-1ext-IgG resulted in a significant increase in the number of donor-derived fibers, as compared to cells expanded on human IgG, reaching engraftment levels similar to freshly isolated cells. Importantly, cells expanded on Delta-1ext-IgG engrafted to the recipient satellite cell niche and contributed to further regeneration. A similar strategy of expanding human muscle-derived cells on Notch ligand might facilitate engraftment and muscle regeneration for patients affected with muscular dystrophy.
Statistics.com at the 10‐year mark
Authors: Bruce Peter 
Published: August 2012

AbstractStatistics.com stands at the intersection of two current trends: (1) an acute shortage of analytic and statistics skills in the labor force and (2) a blossoming of different models for online delivery of higher education. A recent report by the McKinsey Global Institute forecasts a current and continuing shortfall of 140,000–190,000 workers with ‘deep analytical skills’. The skills referred to are in the area of statistics, data mining, and machine learning. Also in the news have been recent ventures by Stanford and other premier universities to offer high‐quality free courses in this area to massive audiences in excess of 100,000. Statistics.com has been building an online program in these subjects since 2002, and now offers 100‐plus online 4‐week courses, relying on an extensive faculty of expert statisticians, and a mixture of traditional and innovative approaches. WIREs Comput Stat 2012, 4:513–517. doi: 10.1002/wics.1225This article is categorized under:

Applications of Computational Statistics > Organizations and Publications
Bax induces activation of the unfolded protein response by inducing HAC1 mRNA splicing in Saccharomyces cerevisiae
Authors: Çakir Birsen 
Published: August 2012

AbstractBax, a multidomain pro‐apoptotic Bcl‐2 protein, localizes to the endoplasmic reticulum (ER), where it regulates ER stress‐induced apoptosis. Adaptation to ER stress depends on the activation of an integrated signal transduction pathway known as the unfolded protein response (UPR). This study examined the death‐inducing activity of Bax and its ability to induce UPR signalling pathways in yeast. We observed that inhibition of global translation in yeast cells expressing Bax correlated with Bax‐induced cell death. Using a lacZ reporter containing several UPR cis‐activating regulatory elements, we also found that Bax directly activated the UPR. Furthermore, this correlated with the splicing of HAC1 mRNA, a gene involved in UPR activation. Bax induced expression of representative UPR target genes such as KAR2, DER1 and GCN4. Finally, we found that Ire1p function is critical for Bax‐induced cell death. Copyright © 2012 John Wiley & Sons, Ltd.
The First Dinuclear Nickel(II) Thiosulfate Obtained From Oxidation of Tri‐tert‐butoxysilanethiol. Contributions to the Chemistry of Silicon‐Sulfur Compounds No. 78[1]
Authors: Pladzyk Agnieszka , Daca Natalia , Ponikiewski Łukasz 
Published: August 2012

AbstractThe title complex, neutral {[Ni2(μ‐S2O3)2(C7H9N)4H2O]C7H8} (1), presents a dinuclear structure with the thiosulfate group acting as a (S, O) chelate and simultaneously as a (S) bridge. The molecular structure was determined by X‐ray crystallography. Complex 1 crystallizes as a hydrogen‐bonded dimer with molecule of toluene solvent in the unit cell. The environment of both central nickel atoms is octahedral with NiN2O2S2 cores. This is the first metal thiosulfate complex isolated as a product of the oxidation of silanethiol. A mechanism of the reaction involving the formation of (RO)3SiSSSi(OR)3 intermediate is proposed with the subsequent cleavage of Si–S bond.
Neue molekulare Indium‐Zinn‐Sauerstoff‐ und Indium‐Zinn‐Natrium‐Sauerstoff‐Chlor‐Cluster
Authors: Veith Michael , Summa Daniela , Huch Volker 
Published: August 2012

AbstractAbstract. The five‐membered heteroelement cluster THF·Cl2In(OtBu)3Sn reacts with the sodium stannate [Na(OtBu)3Sn]2 to produce either the new oxo‐centered alkoxo cluster ClInO[Sn(OtBu)2]3 (1) (in low yield) or the heteroleptic alkoxo cluster Sn(OtBu)3InCl3Na[Sn(OtBu)2]2 (2). X‐ray diffraction analyses reveal that in compound 1 the polycyclic entity is made of three tin atoms which together with a central oxygen atom form a trigonal, almost planar triangle, perpendicular to which a further indium atom is connected through the oxygen atom. The metal atoms thus are arranged in a Sn3In pyramid, the edges of which are all saturated by bridging tert‐butoxy groups. The indium atom has a further chloride ligand. Compound 2 has two trigonal bipyramids as building blocks which are fused together at a six coordinate indium atom. One of the bipyramids is of the type SnO3In with tert‐butyl groups on the oxygen atoms, while the other has the composition InCl3Na with chlorine atoms connecting the two metals. The sodium atom in 2 has further contacts to two plus one alkoxide groups which are part of a[Sn(OtBu)2]2 dimer disposing of a Sn2O2 central cycle. The hetero element cluster in 2 thus combines three closed entities and its skeleton SnO3InCl3NaO2Sn2O2 consists of three different metallic and two different non‐metallic elements.
Hormonal Contraceptive Use and Discontinuation Because of Dissatisfaction: Differences by Race and Education
Authors: Littlejohn Krystale E. 
Published: August 2012

Abstract
The unintended pregnancy rate in the United States remains high, and there are large race and education differences in unintended pregnancy and fertility. These differences make it important to study race and education differences in contraceptive behavior. Using nationally representative data from the 2002 National Survey of Family Growth, this study examines the effects of race and education on the likelihood that women have ever used particular types of hormonal contraception and have ever discontinued hormonal contraception because of dissatisfaction. The results show that blacks and Latinas were more likely to have used injectable contraceptives (“the shot”) and less likely to have used oral contraceptives (“the pill”) than were white women. Women with less education were more likely than college-educated women to have used the shot but there were no significant education differences in use of the pill. Among women who had ever used hormonal birth control, those with less than a college degree were more likely than college-educated women to discontinue the birth control because of dissatisfaction. However, net of education, this study found no significant racial/ethnic differences in discontinuation. The most commonly stated reason for discontinuation because of dissatisfaction was side effects.