bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amphiphilic block glycopolymers via atom transfer radical polymerization: Synthesis, self‐assembly and biomolecular recognition
Authors: León Orietta , Muñoz‐Bonilla Alexandra , Bordegé Vanesa , Sánchez‐Chaves Manuel , Fernández‐García Marta 
Published: April 2011

AbstractIn this work the synthesis of poly(butyl acrylate)‐b‐poly(2‐{[(D‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate) (PBA‐b‐PHEMAGl) diblock glycopolymer and poly(2‐{[(D‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate)‐b‐poly(butyl acrylate)‐b‐poly(2‐{[(D‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate) (PHEMAGl‐b‐PBA‐b‐PHEMAGl) was performed via atom transfer radical polymerization. Monofunctional and difunctional poly(butyl acrylate) macroinitiators were used to synthesize the well‐defined diblock and triblock glycopolymers by chain extension reaction with the glycomonomer HEMAGl. The self‐assembly of these glycopolymers in aqueous solution was studied by dynamic light scattering and transmission electron microcopy, showing the coexistence of spherical micelles and polymeric vesicles. In addition, the biomolecular recognition capacity of these micelles and vesicles, containing glucose moieties in their coronas, was investigated using the lectin Concanavalin A, Canavalia Ensiformis, which specifically interacts with glucose groups. The binding capacity of Concanavalin A with glycopolymer is influenced by the copolymer composition, increasing with the length of HEMAGl glycopolymer segment in the block copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
NMR structure of the Bordetella bronchiseptica protein NP_888769.1 establishes a new phage‐related protein family PF13554
Authors: Wahab Atia‐tul‐ , Serrano Pedro , Geralt Michael , Wüthrich Kurt 
Published: April 2011

AbstractThe solution structure of the hypothetical phage‐related protein NP_888769.1 from the Gram‐negative bacterium Bordetella bronchoseptica contains a well‐structured core comprising a five‐stranded, antiparallel β‐sheet packed on one side against two α‐helices and a short β‐hairpin with three flexibly disordered loops extending from the central β‐sheet. A homology search with the software DALI identified two Protein Data Bank deposits with Z‐scores > 8, where both of these proteins have less than 8% sequence identity relative to NP_888769.1, and one has been functionally annotated as a lambda phage tail terminator protein. A sequence‐homology analysis then confirmed that NP_888769.1 represents the first three‐dimensional structural representative of a new protein family that was previously predicted by the Joint Center for Structural Genomics, which includes so far about 20 prophage proteins encoded in bacterial genomes.
Evolved streptavidin mutants reveal key role of loop residue in high‐affinity binding
Authors: Magalhães Maria L. B. , Czekster Clarissa Melo , Guan Rong , Malashkevich Vladimir N. , Almo Steven C. , Levy Matthew 
Published: April 2011

AbstractWe have performed a detailed analysis of streptavidin variants with altered specificity towards desthiobiotin. In addition to changes in key residues which widen the ligand binding pocket and accommodate the more structurally flexible desthiobiotin, the data revealed the role of a key, non‐active site mutation at the base of the flexible loop (S52G) which slows dissociation of this ligand by approximately sevenfold. Our data suggest that this mutation results in the loss of a stabilizing contact which keeps this loop open and accessible in the absence of ligand. When this mutation was introduced into the wild‐type protein, destabilization of the opened loop conferred a ∼10‐fold decrease in both the on‐rate and off‐rate for the ligand biotin‐4‐fluoroscein. A similar effect was observed when this mutation was added to a monomeric form of this protein. Our results provide key insight into the role of the streptavidin flexible loop in ligand binding and maintaining high affinity interactions.
Breeding of commercially acceptable allelopathic rice cultivars in China
Authors: Kong Chui‐Hua , Chen Xiong‐Hui , Hu Fei , Zhang Song‐Zhu 
Published: April 2011

AbstractBACKGROUND: One promising area of paddy weed control is the potential for exploiting the weed‐suppressing ability of rice. This study was conducted to develop commercially acceptable allelopathic rice cultivars using crosses between allelopathic rice variety PI312777 and commercial Chinese cultivars (N2S, N9S, Huahui354, Peiai64S and Tehuazhan35), and to assess their weed suppression and grain yield in paddy fields in relation to their parents.RESULTS: There was a positive dominance in the crosses Huahui354 × PI312777 and N2S × PI312777 but recessive or negative dominance in N9S × PI312777, Peiai64S × PI312777 and Tehuazhan35 × PI312777. Huahui354 × PI312777 and N2S × PI312777 showed stronger weed suppression than their parents and other crosses. Finally, an F8 line with an appearance close to Huahui354 and a magnitude of weed suppression close to PI312777 was obtained from Huahui354 × PI312777. This line, named Huagan‐3, was released as a first commercially acceptable allelopathic rice cultivar in China. The grain yield and quality of Huagan‐3 met the commercial standard of the local rice industry. Huagan‐3 greatly suppressed paddy weeds, although suppression was influenced by year‐to‐year variation and plant density. There was no certain yield reduction in Huagan‐3 even under a slight infestation of barnyard grass in paddy fields.CONCLUSION: The successful breeding of Huagan‐3 with high yield and strong weed suppression may be incorporated into present rice production systems to minimise the amount of herbicide used. Copyright © 2011 Society of Chemical Industry
Combined use of a synthetic trail pheromone and insecticidal bait provides effective control of an invasive ant
Authors: Sunamura Eiriki , Suzuki Shun , Nishisue Koji , Sakamoto Hironori , Otsuka Megumi , Utsumi Yosaburo , Mochizuki Fumiaki , Fukumoto Takehiko , Ishikawa Yukio , Terayama Mamoru , Tatsuki Sadahiro 
Published: April 2011

AbstractBACKGROUND: Except for sex pheromones, use of pheromones in pest management has been largely unexplored. A high concentration of trail pheromone disrupts ant trail following and foraging, and thus synthetic trail pheromone can be a novel control agent for pest ants. In this study, a year‐long treatment of small areas (100 m2 plots of urban house gardens) with synthetic trail pheromone, insecticidal bait or both was conducted to develop a novel control method of the invasive Argentine ant Linepithema humile (Mayr).RESULTS: The ant population could be maintained lower than or similar to the initial level only by combined treatment with synthetic trail pheromone and insecticidal bait. Actually, the ant population was nearly always lowest in combination treatment plots. Throughout the study period, the ant population in plots treated with either one of synthetic trail pheromone or insecticidal bait remained similar to no‐treatment plots.CONCLUSIONS: Combination treatment may be a more effective and environmentally friendly method for controlling invasive ants than conventional methods. Extermination of ants by insecticidal bait and inhibition of re‐infestation by pheromone may be the mechanism of the combination effect. This is the first study to show a significant effect of synthetic trail pheromone on ant population. Copyright © 2011 Society of Chemical Industry
On the effects of a totally reflecting barrier on an unbiased 1D random walk
Authors: Hansen Scott K. 
Published: April 2011

AbstractThis paper is devoted to discussing the behavior of an unbiased 1D random walk in a semi‐infinite lattice confined by a certain type of boundary, termedtotally reflecting, and in particular to proving the validity of the so‐called “reflection principle” for computing the probability mass function in such systems. This is motivated by the publication of an earlier paper by [Orlowski, Phys. Status Solidi B239, 158–161 (2003)], which denied the validity of the reflection principle, and proposed a different, inconsistent method of computing the walker's probability mass, and also by the fact that earlier authors published arguments for the reflection principle that themselves contained errors or were not entirely rigorous. This paper provides a new, rigorous argument for the validity of the reflection principle, and also shows where the error in Orlowski's analysis lies. It further contextualizes these arguments with respect to some existing literature on similar systems where the probability of reflection may be less than unity, and discusses the proper relationship between the discrete random walk, the diffusion equation, and approches which employ a different, master equation‐based discretization technique. The spatial relationship between the discrete and continuous formulations is discussed, and an existing derivation [van Kampen and Oppenheim, J. Math. Phys.13, 842–849 (1972)] is extended. Finally, it is shown that the reflection principle, as outlined in this paper, preserves initially uniform concentrations for all time (in contrast to Orlowski's proposed method).
Kondo lattice – fluctuating valence transition in Ce(Cu1–xNix)4Al compounds
Authors: Toliński T. , Kostrzewa D. , Synoradzki K. , Szlaferek A. , Wencka M. , Dolinšek J. 
Published: April 2011

AbstractThe Ce(Cu1–xNix)4Al series of compounds has been studied for 0 <x < 1. The physical properties have been determined by X‐ray diffraction, magnetometric, specific heat and electrical resistivity measurements. It is observed that the monotonic change of the unit cell volume is accompanied by the change of the magnetic and thermodynamic parameters.The transition from the Kondo lattice to the fluctuating valence (FV) state is observed without the dilution of Ce but by the increase of x, which is accompanied by the decrease of the electronic specific heat coefficient, increase of the splitting of the crystal field levels and damping of the resistivity maximum.
Investigation of polarization‐induced electric field in ultrathin InAlN layers on GaN by X‐ray photoelectron spectroscopy
Authors: Akazawa M. , Gao B. , Hashizume T. , Hiroki M. , Yamahata S. , Shigekawa N. 
Published: April 2011

AbstractThe polarization‐induced electric field in ultrathin InxAl1‐xN (0.17 ≤ x ≤ 0.30) layers on GaN was investigated by using X‐ray photoelectron spectroscopy (XPS). The core‐level energy position, ECL, and the full width at half maximum (FWHM) of the Al2p, In4d, and In3d spectra from 2.5‐nm‐thick InAlN layers increased with the increase in the photoelectron exit angle (elevation angle). These increases were well reproduced with numerical calculations assuming polarization‐induced internal fields combined with surface Fermi level pinning. The magnitudes of the internal field decreased as the In molar fraction increased. The Ga3d spectra from the host GaN layers markedly shifted by 530 meV depending on the molar fraction of InAlN layers, which was independent of the exit angle. This indicated that the Fermi level was unpinned at the interfaces, or GaN surfaces, and shifted due to the potential drop in the InAlN layers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tailoring opto‐electronic properties of small InAsN and InN quantum dots
Authors: Pozhar Liudmila A. 
Published: April 2011

AbstractElectronic energy level structure (ELS), charge and spin density distributions (CDD and SDD, respectively) of small indium nitride clusters have been studied by means of the first‐principle, many‐body field theoretical methods. Electron charge delocalization due to charge accumulation on nitrogen and dopant nickel atoms, and resulting violation of the octet rule of the valence theory, have been observed. This charge delocalization mechanism provides for minimization of the total cluster energy, and thus is necessary to stabilize small non‐stoichiometric indium nitride systems. It may be used to manipulate opto‐electronic properties of indium nitride clusters, and also to synthesize novel, indium nitride‐based nanostructures with desirable properties (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhancement of radiative recombination time under forward bias voltage in a green (In,Ga)N multiple‐quantum‐well light‐emitting‐diode
Authors: Satake Akihiro , Sato Junichi , Fujisaki Tsuyoshi , Fujiwara Kenzo 
Published: April 2011

AbstractRadiative recombination dynamics has been investigated by time‐resolved photoluminescence (PL) spectroscopy in a c ‐plane green (In,Ga)N multiple‐quantum‐well light‐emitting diode under applied bias voltage at 20 K. The PL spectral peak shows a large blueshift with increasing reverse voltage, exhibiting the existence of internal polarization field. The effective PL lifetime decreases when the applied voltage is changed from +2 to −10 V. It is due to competition between the quantum‐confined Stark effect (QCSE) and a carrier escape from the wells. A relative radiative recombination time is obtained by dividing the effective PL lifetime by the PL intensity as a function of the applied voltage. The relative radiative recombination time is significantly increased under the applied voltage between −2 and +2 V due to strongly enhanced QCSE. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aluminum nitride homoepitaxial growth on polar and non‐polar AlN PVT substrates by high temperature CVD (HTCVD)
Authors: Claudel Arnaud , Chowanek Yann , Blanquet Elisabeth , Chaussende Didier , Boichot Raphaël , Crisci Alexandre , Berthomé G. , Mank Hugues , Luca Sorana , Pique Didier , Pons Michel 
Published: April 2011

AbstractDue to its wide bandgap (6.2 eV), its high thermal conductivity (3.3 WK‐1cm‐1) and high electrical resistivity (1013 Ωcm), AlN is a very expected III‐N semiconductor for applications in high power electronics (HEMTs) and optoelectronics (UV LEDs). In this work, the homoepitaxial growth of aluminum nitride on polar and non‐polar AlN PVT seeds by HTCVD is studied. From our knowledge, the AlN homoepitaxial growth by HVPE or HTCVD on polar and non‐polar bulk AlN substrates has not been reported. The potential of investigation in this new range of experiments conditions, i.e. high temperature and high growth rate, as well as the deposition of non‐polar AlN crystals (Paskova, Phys. Status Solidi B 245(6), 1011 (2008) and Schwarz and Kneissl, Phys. Status Solidi RRL 1(3), A44 (2007) [1, 2]) is very promising for epitaxial growth and could extend the field of applications (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of interface formation on the structural quality of AlN single crystals grown by sublimation method
Authors: Sumathi R. R. , Barz R. U. , Gille P. , Straubinger T. 
Published: April 2011

AbstractAlN single crystals with 25 mm diameter and 3 mm thickness were grown on on‐axis, Si‐terminated, (001) 6H‐SiC substrates with a growth rate of 20‐25 μm/h by the sublimation method. The growth conditions were optimised and the grown crystals exhibit good crystalline quality as analysed by double‐crystal x‐ray diffraction measurements. The FWHM value of the rocking curves in ω‐scan is about 100 arcsec for 3 mm thick crystals. The kind of AlN/SiC interface formation influences the structural quality of the grown crystals by forming low‐angle grain boundaries. Optical and scanning electron microscopic analyses performed on cross‐cut samples demonstrate the existence of an array of hillocks and voids between them at the bottom of the grown AlN layer. These hillocks are confirmed by electron probe micro analysis as SiC etch hillocks and their origin was investigated. The possible mechanism for the formation of low‐angle grain boundaries is discussed and a simple physical model is proposed. Optimisation of the growth conditions was carried out in order to obtain crystals with low silicon carbide incorporation. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
(Al,Ga)N overgrowth over AlN ridges oriented in [1120] and [1100] direction
Authors: Kueller V. , Knauer A. , Zeimer U. , Rodriguez H. , Mogilatenko A. , Kneissl M. , Weyers M. 
Published: April 2011

AbstractEpitaxial lateral overgrowth of 1.5 µm wide AlN ridges with 1.5 µm spacing with AlGaN or AlN was investigated by electron microscopy and cathodoluminescence. Overgrowth of [1100] oriented stripes leads to relatively smooth c‐plane AlGaN surfaces while on [1120] oriented stripes strongly facetted surfaces evolve. The growth on the different facets leads to strong compositional fluctuations. These fluctuations can be prevented by the growth of binary AlN over the ridges instead of AlGaN. Only the [1100] oriented ridges formed smooth surfaces, suitable for subsequent deposition of AlGaN with homogeneous composition. The lateral epitaxial overgrowth leads to a remarkable reduction in threading dislocation density as shown by TEM and X‐ray diffraction. The critical thickness of AlN before cracking was significantly increased in comparison to unpatterned growth. The resulting AlN template is a promising ultraviolet transparent template for LED. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Concise Review: Mesenchymal Stem Cells for Acute Lung Injury: Role of Paracrine Soluble Factors
Authors: Lee Jae W. , Fang Xiaohui , Krasnodembskaya Anna , Howard James P. , Matthay Michael A. 
Published: April 2011

AbstractMorbidity and mortality have declined only modestly in patients with clinical acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), despite extensive research into the pathophysiology. Current treatment remains primarily supportive with lung-protective ventilation and a fluid conservative strategy. Pharmacologic therapies that reduce the severity of lung injury in preclinical models have not yet been translated to effective clinical treatment options. Consequently, further research in translational therapies is needed. Cell-based therapy with mesenchymal stem cells (MSCs) is one attractive new therapeutic approach. MSCs have the capacity to secrete multiple paracrine factors that can regulate endothelial and epithelial permeability, decrease inflammation, enhance tissue repair, and inhibit bacterial growth. This review will focus on recent studies, which support the potential therapeutic use of MSCs in ALI/ARDS, with an emphasis on the role of paracrine soluble factors.
Site‐selective versus promiscuous A‐to‐I editing
Authors: Wahlstedt Helene , f#x2013;hman Marie 
Published: April 2011

AbstractRNA editing by adenosine deamination is acting on polymerase II derived transcripts in all metazoans. Adenosine‐to‐inosine (A‐to‐I) editing is mediated by the adenosine deaminase that acts on RNA (ADAR) enzymes. Two types of adenosine to inosine (A‐to‐I) RNA editing have been defined: site selective and hyper‐editing. Typically, in site selectively edited substrates, one or a few A‐to‐I sites are edited in double‐stranded RNA structures, frequently interrupted by single‐stranded bulges and loops. Hyper‐editing occurs in long stretches of duplex RNA where multiple adenosines are subjected to deamination. In this review, recent findings on editing within noncoding RNA as well as examples of site selective editing within coding regions are presented. We discuss how these two editing events have evolved and the structural differences between a site selective and hyper‐edited substrate. WIREs RNA 2011 2 761–771 DOI: 10.1002/wrna.89This article is categorized under:

RNA Processing > RNA Editing and Modification
Obesity and Knee Osteoarthritis Are Not Associated With Impaired Quadriceps Specific Strength in Adults
Authors: Segal Neil A. , Zimmerman M. Bridget , Brubaker Morgan , Torner James C. 
Published: April 2011

ObjectiveTo assess whether adults, aged 50‐59 years, who are obese or moderately to severely obese have impaired quadriceps strength and muscle quality in comparison with adults who are not obese, both groups with and without knee osteoarthritis (OA).DesignCross‐sectional observational study.SettingRural community acquired sample.SubjectsSeventy‐seven men and 84 women, aged 50‐59 years.MethodsComparisons by using mixed models for clustered data (2 lower limbs per participant) between groups defined by body mass index (BMI) (<30 kg/m2, 30‐35 kg/m2, and ≥35 kg/m2), with and without knee OAMain Outcome MeasurementThe slope of the relationship between quadriceps muscle cross‐sectional area (CSA) and isokinetic knee extensor strength (dynamometer) in each BMI and OA group.ResultsThere were 113 limbs (48.7% women), 101 limbs (38.6% women), and 89 limbs (73.0% women) in the <30 kg/m2, 30‐35 kg/m2, and ≥35 kg/m2 BMI groups, respectively; knee OA was present in 10.6%, 28.7%, and 58.4% of the limbs in each of these respective groups. Quadriceps CSA did not significantly differ among BMI groups in either gender or between subjects with and without knee OA. Peak quadriceps strength also did not significantly differ by BMI group or by the presence of knee OA. Multivariable analyses also demonstrated that peak quadriceps strength did not differ by BMI group, even after adjusting for (a) gender, (b) OA status, (c) intramuscular fat, or (d) quadriceps attenuation. The slopes for the relationships between quadriceps strength and CSA did not differ by BMI group, OA status, or their interaction.ConclusionsIndividuals who were obese and at risk for knee OA did not appear to have altered muscle strength or muscle quality compared with adults who were not obese and were aged 50‐59 years. The absence of a difference in the relationship between peak quadriceps strength and CSA provided further evidence that there was not an impairment in quadriceps muscle quality in this cohort, which suggests that factors other than strength might mediate the association between obesity and knee OA.
Four thousand years of environmental change and human activity in the Cochabamba Basin, Bolivia
Authors: Williams Joseph J. , Gosling William D. , Coe Angela L. , Brooks Stephen J. , Gulliver Pauline 
Published: April 2011

AbstractThe Cochabamba Basin (Bolivia) is on the ancient road network connecting Andean and lowland areas. Little is known about the longevity of this trade route or how people responded to past environmental changes. The eastern end of the Cochabamba valley system constricts at the Vacas Lake District, constraining the road network and providing an ideal location in which to examine past human–environmental interactions. Multiproxy analysis of sediment from Lake Challacaba has allowed a c. 4000 year environmental history to be reconstructed. Fluctuations in drought tolerant pollen taxa and calcium carbonate indicate two periods of reduced moisture availability (c. 4000–3370 and c. 2190–1020 cal yr BP) compared to adjacent wetter episodes (c. 3370–2190 and c. 1020 cal yr BP–present). The moisture fluctuations broadly correlate to El Niño/Southern Oscillation variations reported elsewhere. High charcoal abundance from c. 4000 to 2000 yr ago indicates continuous use of the ancient road network. A decline in charcoal and an increase in dung fungus (Sporormiella) c. 1340–1210 cal yr BP, suggests that cultural changes were a major factor in shaping the modern landscape. Despite undisputable impacts of human populations on the Polylepis woodlands today, we see no evidence of woodland clearance in the Challacaba record.