bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of ionic liquids for biocatalytic synthesis of sugar derivatives
Authors: Galonde Nadine , Nott Katherine , Debuigne Antoine , Deleu Magali , Jerôme Christine , Paquot Michel , Wathelet Jean‐Paul 
Published: February 2012

AbstractSugar‐based compounds are widely used in pharmaceuticals, cosmetics, detergents and food. They are mainly produced by chemical methods, but the use of enzymes as ‘a greener alternative’ to organic synthesis has been investigated for more than 20 years. Due to the low polar substrate solubility in organic solvents compatible with enzymes, research has focused on the application of substitutes for biocatalysis, especially ionic liquids (ILs). After introducing the main properties of ILs and especially their ability to solubilize sugars, this review focuses on one of their applications, the biocatalytic synthesis of carbohydrate derivatives. In this context, they can be used in pure IL systems, in IL/IL systems or in IL/organic solvent systems. Finally, this review provides an update on the environmental fate of ILs. Their exploitation in ‘green’ processes is still limited due to their low degradability but research is currently under way to design new more ‘eco‐friendly’ ILs. Copyright © 2012 Society of Chemical Industry
Early entry and deformation of macropinosomes correlates with high efficiency of decaarginine‐polyethylene glycol‐lipid‐mediated gene delivery
Authors: Kobayashi Shouhei , Hattori Yoshiyuki , Osakada Hiroko , Toma Kazunori , Maitani Yoshie , Hiraoka Yasushi , Haraguchi Tokuko 
Published: February 2012

AbstractBackgroundDecaarginine‐polyethylene glycol‐conjugated 3,5‐bis(dodecyloxy)benzamide/plasmid DNA [Arg10‐polyethylene glycol (PEG)‐lipid/plasmid DNA (pDNA)] complexes (designated R10B/DNA complexes) are efficient nonviral carriers for pDNA delivery into human cervical carcinoma HeLa cells. Previous reports indicated that these complexes formed at a relatively low R10B/DNA ratio and showed high transgene expression efficiency. However, the intracellular behaviour of the two different nanostructures, which leads to differences in gene delivery, remains to be elucidated.MethodsR10B/DNA complexes prepared at a N/P ratio of 8.5/1 or 42.5/1, corresponding to 5 µm or 25 µm R10B, respectively, were added to HeLa cells, and their uptake and subsequent intracellular fate were examined by cell imaging using electron microscopy (EM) and correlative light‐electron microscopy (CLEM).ResultsEM and CLEM analyses revealed that R10B/DNA complexes formed at the lower N/P ratio were mainly taken up by the cells through macropinocytosis, whereas R10B/DNA complexes formed at the higher N/P ratio bound to protruding membrane structures or permeated into the cells by a different pathway. In cells expressing the transgene, R10B/DNA complexes were observed both in macropinosomes and in the cytoplasm. In addition, these cells had macropinosomes with disrupted membranes. These results suggest that cellular uptake through macropinocytosis and subsequent disruption of the macropinosome membrane may be a critical step for R10B‐mediated gene delivery.ConclusionsWe have shown that the existence of R10B/DNA complexes in macropinosomes at the early stages of gene delivery correlates with high efficiency R10B‐mediated gene delivery. This finding will provide valuable insights for the engineering of more efficient gene delivery systems based on oligoarginine‐mediated carriers. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis and Characterization of [2.2]Paracyclophane‐Containing Conjugated Microporous Polymers
Authors: Morisaki Yasuhiro , Gon Masayuki , Tsuji Yuichi , Kajiwara Yuichi , Chujo Yoshiki 
Published: February 2012

AbstractConjugated microporous polymers (CMPs) are prepared from disubstituted and tetrasubstituted [2.2]paracyclophane monomers by a Sonogashira–Hagihara coupling. The polymers obtained exhibit a type I nitrogen gas adsorption profile and H4‐like hysteresis loops, indicating that the [2.2]paracyclophane‐containing CMPs possess slit‐like mesopores. Their Brunauer–Emmett–Teller surface areas are estimated to be above 500 m2 g−1. The step and stacked structure of the [2.2]paracyclophane unit affects the morphology of the polymers because of the contribution of two‐dimensional expansion of the polymer network.
Investigation of Thermoresponsive Nano‐Confined Polymer Brushes by AFM‐Based Force Spectroscopy
Authors: Radji Sadia , Alem Halima , Demoustier‐Champagne Sophie , Jonas Alain M. , Cuenot Stéphane 
Published: February 2012

AbstractPNIPAM polymer brushes are synthesized in nanopores of track‐etched membranes. The internal structure of these nano‐confined brushes is studied by AFM force spectroscopy experiments as a function of the synthesis conditions. The approach force vs. distance profiles are fitted using the Alexander‐de Gennes model to determine the grafting density, and the worm‐like chain model is used to estimate the chain length from the retract profiles. The grafting density for brushes synthesized within 80 nm pores is ten times lower than that obtained in 330 nm pores. For the same polymerization time, the chain lengths are much lower if the synthesis is carried out in small pores. The elastic properties of the brushes are also directly related to the confinement conditions.
Wavelength conversion using rare earth doped oxides in polyolefin based nanocomposite films
Authors: Jadhav Abhijit , Pawar Amol , Hwang Tae Ryong , Lee Jae Wook , Choi Min Wook , Kyu Kim Byung , Kang Young Soo 
Published: February 2012

AbstractNanocomposites are a new class of polymeric materials which include organic or inorganic nano‐phase materials. These nanocomposite films can show interesting properties which have many applications for wavelength conversion and energy saving. In this paper, we present polyolefin based nanocomposite films prepared using wavelength‐converting red ‘phosphors’ such as Y2O3: Eu3+ and LiAl5O8:Fe3+ and blue ‘phosphor’ CaMgSi2O6: Eu2+. The durability of the polymer chain is unaffected by incorporation of inorganic nanoparticles as there is no direct interaction between them. The addition of surfactant in the nanocomposite film helps to improve the dispersion ability of the nanoparticles and increase the flexibility of the polymer film. Wavelength‐converting ‘nanophosphors’ incorporated in a polymer matrix help to increase the tensile strength of the film. The films show excellent wavelength conversion ability of UV light into the visible and near IR range. These nanocomposite films have great application in energy saving devices. Copyright © 2012 Society of Chemical Industry
Computational investigation of the HIV‐1 Rev multimerization using molecular dynamics simulations and binding free energy calculations
Authors: Venken Tom , Daelemans Dirk , De Maeyer Marc , Voet Arnout 
Published: February 2012

AbstractThe HIV Rev protein mediates the nuclear export of viral mRNA, and is thereby essential for the production of late viral proteins in the replication cycle. Rev forms a large organized multimeric protein‐protein complex for proper functioning. Recently, the three‐dimensional structures of a Rev dimer and tetramer have been resolved and provide the basis for a thorough structural analysis of the binding interaction. Here, molecular dynamics (MD) and binding free energy calculations were performed to elucidate the forces thriving dimerization and higher order multimerization of the Rev protein. It is found that despite the structural differences between each crystal structure, both display a similar behavior according to our calculations. Our analysis based on a molecular mechanics‐generalized Born surface area (MM/GBSA) and a configurational entropy approach demonstrates that the higher order multimerization site is much weaker than the dimerization site. In addition, a quantitative hot spot analysis combined with a mutational analysis reveals the most contributing amino acid residues for protein interactions in agreement with experimental results. Additional residues were found in each interface, which are important for the protein interaction. The investigation of the thermodynamics of the Rev multimerization interactions performed here could be a further step in the development of novel antiretrovirals using structure based drug design. Moreover, the variability of the angle between each Rev monomer as measured during the MD simulations suggests a role of the Rev protein in allowing flexibility of the arginine rich domain (ARM) to accommodate RNA binding. Proteins 2012; © 2012 Wiley Periodicals, Inc.
Evolutionary information hidden in a single protein structure
Authors: Shih Chien‐Hua , Chang Chih‐Min , Lin Yeong‐Shin , Lo Wei‐Cheng , Hwang Jenn‐Kang 
Published: February 2012

AbstractThe knowledge of conserved sequences in proteins is valuable in identifying functionally or structurally important residues. Generating the conservation profile of a sequence requires aligning families of homologous sequences and having knowledge of their evolutionary relationships. Here, we report that the conservation profile at the residue level can be quantitatively derived from a single protein structure with only backbone information. We found that the reciprocal packing density profiles of protein structures closely resemble their sequence conservation profiles. For a set of 554 nonhomologous enzymes, 74% (408/554) of the proteins have a correlation coefficient > 0.5 between these two profiles. Our results indicate that the three‐dimensional structure, instead of being a mere scaffold for positioning amino acid residues, exerts such strong evolutionary constraints on the residues of the protein that its profile of sequence conservation essentially reflects that of its structural characteristics. Proteins 2012;. © 2012 Wiley Periodicals, Inc.
Quality‐factor enhancement of optical modes mediated by strong coupling in micron‐size semiconductor disks
Authors: Benyoucef M. , Shim J.‐B. , Wiersig J. , Schmidt O. G. 
Published: February 2012

AbstractWe investigate whispering gallery modes (WGMs) in coupled microdisks both experimentally and theoretically. In order to compensate small fluctuations in the mode energies, we controllably increase the refractive index of a microdisk by local laser heating leading to a red‐shift of the confined modes. The maximum red‐shift and a nearly unchanged Q‐factor are achievable only if the laser beam is located at the center of the disk, while linewidth broadening is observed when the laser beam is focused far from the disk center. When WGM frequencies of two or even three disks are brought into resonance, clear anticrossings are observed, which witness the strong coupling between the resonators. The Q‐factors in strongly coupled resonators are investigated experimentally and theoretically. The Q‐factors of the same order WGMs show a splitting behavior leading to the formation of high‐quality and low‐quality supermodes. magnified image
Epitaxial growth of lateral quantum dot molecules
Authors: Zallo Eugenio , Atkinson Paola , Wang Lijuan , Rastelli Armando , Schmidt Oliver G. 
Published: February 2012

AbstractWe present an overview and a comparison between three different methods of creating low density lateral In(Ga)As quantum dot molecules (QDMs) embedded in a GaAs matrix. Each of them is based on the use of nanoholes to control the dot nucleation site and generate the QDMs. The three methods used to create suitable nanoholes are: (1) In situ excess gallium droplet etching, where the nanohole shape is modified by overgrowth of a thin GaAs buffer to give QDM nucleation. (2) Ex situ electron‐beam lithographic patterning and wet‐etching, where the patterned nanohole size is critical for formation of QDMs. (3) In situ strain‐selective etching of buried InAs quantum dots by AsBr3. The mechanisms of QDM formation, dependence on growth parameters, advantages and disadvantages of each technique and future challenges are discussed.
Anticancer Activity of Morinda citrifolia (Noni) Fruit: A Review
Authors: Brown Amy C. 
Published: February 2012

This review investigated the relationship of noni juice, or its extract (fruit, leaves or root), to anticancer and/or immunostimulant properties. A Medline search was conducted using the key search words ‘Morinda citrifolia’ and ‘Morinda citrifolia and cancer’ (1964 to October, 2011) along with cross‐referencing. Botanical and chemical indexes were not included. A total of 304 and 29 (10%) articles, respectively, were found under these key terms. Of the 19 studies actually related to cancer, seven publications were in vitro cancer studies, nine were in vivo animal cancer studies, and three were in vivo human cancer studies. Among the in vitro studies, a ‘concentrated component’ in noni juice and not pure noni juice may (1) stimulate the immune system to ‘possibly’ assist the body fight the cancer, and (2) kill a small percentage (0–36%) of cancer cells depending on the type. The nine animal studies suggest that a concentrated component in noni juice may stimulate the immune system; but only slightly increases the number (about 1/3; 25–45%) of surviving mice. Other than two case studies, only two human clinical studies existed. The first consisted of testing freeze‐dried noni fruit, which reduced pain perception, but did not reverse advanced cancer. The second was on smokers ingesting an unknown concentration of noni juice who experienced decreased aromatic DNA adducts, and decreased levels of plasma superoxide anion radicals and lipid hydroperoxide.Factors to consider in the future are clearly defining the substance being tested, and whether or not the juice is pasteurized. Some reports of hepatotoxicity exist, although there were confounding factors in most of the case reports. More importantly, noni juice is high in potassium and needs to be monitored by patients with kidney, liver or heart problems. In conclusion, a few in vitro and in vivo animal studies suggest a possible unidentified substance in unpasteurized noni fruit juice that may have a small degree of anticancer activity. The isolation of the active component warrants further research. Copyright © 2012 John Wiley & Sons, Ltd.
Chemical Vapor Deposition of Graphene on Copper from Methane, Ethane and Propane: Evidence for Bilayer Selectivity
Authors: Wassei Jonathan K. , Mecklenburg Matthew , Torres Jaime A. , Fowler Jesse D. , Regan B. C. , Kaner Richard B. , Weiller Bruce H. 
Published: February 2012

AbstractTo study the effects of hydrocarbon precursor gases, graphene is grown by chemical vapor deposition from methane, ethane, and propane on copper foils. The larger molecules are found to more readily produce bilayer and multilayer graphene, due to a higher carbon concentration and different decomposition processes. Single‐ and bilayer graphene can be grown with good selectivity in a simple, single‐precursor process by varying the pressure of ethane from 250 to 1000 mTorr. The bilayer graphene is AB‐stacked as shown by selected area electron diffraction analysis. Additionally propane is found to only produce a combination of single‐ to few‐layer and turbostratic graphene. The percent coverage is investgated using Raman spectroscopy and optical, scanning electron, and transmission electron microscopies. The data are used to discuss a possible mechanism for the second‐layer growth of graphene involving the different cracking pathways of the hydrocarbons.
Improving software security with static automated code analysis in an industry setting
Authors: Baca Dejan , Carlsson Bengt , Petersen Kai , Lundberg Lars 
Published: February 2012

SUMMARYSoftware security can be improved by identifying and correcting vulnerabilities. In order to reduce the cost of rework, vulnerabilities should be detected as early and efficiently as possible. Static automated code analysis is an approach for early detection. So far, only few empirical studies have been conducted in an industrial context to evaluate static automated code analysis. A case study was conducted to evaluate static code analysis in industry focusing on defect detection capability, deployment, and usage of static automated code analysis with a focus on software security. We identified that the tool was capable of detecting memory related vulnerabilities, but few vulnerabilities of other types. The deployment of the tool played an important role in its success as an early vulnerability detector, but also the developers perception of the tools merit. Classifying the warnings from the tool was harder for the developers than to correct them. The correction of false positives in some cases created new vulnerabilities in previously safe code. With regard to defect detection ability, we conclude that static code analysis is able to identify vulnerabilities in different categories. In terms of deployment, we conclude that the tool should be integrated with bug reporting systems, and developers need to share the responsibility for classifying and reporting warnings. With regard to tool usage by developers, we propose to use multiple persons (at least two) in classifying a warning. The same goes for making the decision of how to act based on the warning. Copyright © 2012 John Wiley & Sons, Ltd.
A Heterogeneous Catalyst for Transesterification of Argemone mexicana Oil
Authors: Sharma Meeta , Khan Arif Ali , Dohhen Khem C. , Christopher J. , Puri Suresh K. , Tuli Deepak K. , Sarin Rakesh 
Published: February 2012

AbstractA novel CaO based catalyst, CaO–Ca12Al14O33 binary complex has been synthesized for the production of biodiesel from vegetable oils. The catalyst has been prepared on the basis of integration of CaO, as solid reactant, with a composite metal oxide, Ca12Al14O33. A non‐traditional oilseed, Argemone mexicana was examined in detail as a reliable and economical bioresource for biodiesel production. The oil was extracted from the seeds and was transesterified with methanol, using a CaO–Ca12Al14O33 catalyst vis‐à‐vis with a conventional homogeneous sodium methoxide catalyst. In addition to providing a trouble free work‐up of the reaction mixture, the novel catalyst could also be reused up to five cycles, without any major loss of its catalytic activity. Good catalytic activity of the developed catalyst has also been found in transesterification of two others non‐edible oils viz. Jatropha curcas and Guizotia abyssinica. The fuel properties of the synthesized methyl ester of A. mexicana oil have been studied and found to meet the ASTM D‐6751 specification of biodiesel, except for the oxidation stability and Conradson Carbon Residue properties.
b-Coloring graphs with large girth
Authors: Campos Victor , de Farias Victor A. E. , Silva Ana 
Published: February 2012

Abstract
A b-coloring of a graph is a coloring of its vertices such that every color class contains a vertex that has a neighbor in all other classes. The b-chromatic number of a graph is the largest integer k such that the graph has a b-coloring with k colors. We show how to compute in polynomial time the b-chromatic number of a graph of girth at least 9. This improves the seminal result of Irving and Manlove on trees.
Maternal models of risk: Links between substance use and risky sexual behavior in African American female caregivers and daughters
Authors: Brakefield Tiffany , Wilson Helen , Donenberg Geri 
Published: February 2012

ABSTRACTAfrican American (AA) adolescent girls are at heightened risk for HIV and sexually transmitted infections (STIs), and thus knowledge of factors related to risky sexual behavior in this population is crucial. Using Social Learning Theory (Bandura, 1977), this paper examines pathways from female caregivers’ risky sexual behavior and substance use to adolescent girls’ risky sexual behavior and substance use in a sample of 214 low‐income, urban AA female caregivers and daughters recruited from outpatient mental health clinics in Chicago. Structural equation modeling (SEM) revealed that sexual risk reported by female caregivers was associated with adolescent sexual risk, and illicit drug use reported by female caregivers was related to adolescent‐reported substance use, which was in turn associated with adolescent‐reported sexual risk behavior. These findings suggest that female caregivers’ sexual behavior and substance use both relate to girls’ sexual risk. Thus, results emphasize the role of female caregivers in transmitting risk.
A novel SRD5A2 mutation in a Taiwanese newborn with ambiguous genitalia
Authors: Tsai Meng‐Che , Chou Yen‐Yin , Lin Shio‐Jean , Tsai Li‐Ping 
Published: February 2012

AbstractThe 5α‐reductase type 2 deficiency is a rare autosomal recessive 46,XY disorder of sex development caused by the mutated 5α‐reductase type 2 (SRD5A2) gene. In this disease, defective conversion of testosterone to dihydrotestosterone leads to variable presentations of male ambiguous genitalia during fetal development. The most crucial clinical decision for the affected individual is proper gender assignment; therefore, a prompt and correct diagnosis is important. In this present study, we report a normal male karyotype manifesting microphallus, bifid scrotum/labia majora with bilateral palpable gonads, and a blind‐ended pseudovagina. The mutation analysis of the SRD5A2 gene revealed one novel C to T transition changing glutamine to a stop codon at codon 71 (p.Q71X) in exon 1 and one known G to A transition changing arginine to glutamine at codon 227 (p.R227Q) in exon 4. The p.Q71X mutation presumably results in a truncated protein, while the p.R227Q mutation is conceived to impair enzyme function and has been reported in patients of East Asian descent. This report demonstrates the essential role of hormonal and molecular studies for genetic counseling and gender assignment in males with pseudovaginal disorder of sex development, and our report helps identify a novel SRD5A2 gene mutation in the Taiwanese population.
Quantification of Plasmodium falciparum malaria from complex infections in the Peruvian Amazon using quantitative PCR of the merozoite surface protein 1, block 2 (PfMSP1-B2): in vitro dynamics reveal density-dependent interactions
Authors: ZERVOS THOMAS M. , HERNANDEZ JEAN N. , SUTTON PATRICK L. , BRANCH ORALEE H. 
Published: February 2012

SUMMARYThe majority of Plasmodium falciparum field isolates are defined as complex infections because they contain multiple genetically distinct clones. Studying interactions between clones in complex infections in vivo and in vitro could elucidate important phenomena in malaria infection, transmission and treatment. Using quantitative PCR (qPCR) of the P. falciparum merozoite surface protein 1, block 2 (PfMSP1-B2), we provide a sensitive and efficient genotyping method. This is important for epidemiological studies because it makes it possible to study genotype-specific growth dynamics. We compared 3 PfMSP1-B2 genotyping methods by analysing 79 field isolates from the Peruvian Amazon. In vivo observations from other studies using these techniques led to the hypothesis that clones within complex infections interact. By co-culturing clones with different PfMSP1-B2 genotypes, and measuring parasitaemia using qPCR, we found that suppression of clonal expansion was a factor of the collective density of all clones present in a culture. PfMSP1-B2 qPCR enabled us to find in vitro evidence for parasite-parasite interactions and could facilitate future investigations of growth trends in naturally occurring complex infections.