bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Amphiphilic Glycopolymers Based on a Polycaprolactone‐maleic anhydride Copolymer Backbone: Characterization by 15N NMR and Application to Colloidal Stabilization of Nanoparticles
Authors: Otman Otman , Boullanger Paul , Lafont Dominique , Hamaide Thierry 
Published: November 2008

Abstract8‐Amino‐3,6‐dioxaoctyl α‐D‐mannopyranoside and 8‐amino‐3,6‐dioxaoctyl β‐D‐galactopyranoside were prepared for coupling with a copolymer made from PCL macromonomers and MA. The new glycosyl compounds as well as PCL macromonomers were synthesized by appropriate techniques and fully characterized. The grafting of the latter with the functionalized copolymer was ascertained by 15N NMR experiments. The glycopolymers thus obtained were used in conjunction with Pluronic® F‐68 for the stabilization of PCL nanoparticles prepared by the emulsification‐diffusion technique. The stabilization of these nanoparticles upon storage and after centrifugation was investigated as well.magnified image
Segregated Networks of Carbon Black in Poly(vinyl acetate) Latex: Influence of Clay on the Electrical and Mechanical Behavior
Authors: Miriyala Sethu M. , Kim Yeon Seok , Liu Lei , Grunlan Jaime C. 
Published: November 2008

AbstractFilms were prepared from mixtures of PVAc latex, CB, and natural sodium montmorillonite clay. In the absence of clay, these composites exhibit a percolation threshold of 1.2 vol.‐% CB, which is nearly an order of magnitude lower than that observed for composites prepared using PVAc solution. SEM images reveal a segregated CB network that is the result of excluded volume created by the much larger polymer particles in the latex. With the addition of 0.2 wt.‐% clay, the percolation threshold is reduced to 0.9 vol.‐% carbon black due to clay‐induced networking. The storage modulus is also enhanced by the presence of clay, although higher clay concentration appears to adversely affect electrical and mechanical behavior of these composites.magnified image
Anisotropic Electronic Conductivity in Layer‐By‐Layer Composite Film Composed of Water‐Soluble Conjugated Polymers and SWNTs
Authors: Adachi Naoya , Fukawa Tadashi , Tatewaki Yoko , Shirai Hirofusa , Kimura Mutsumi 
Published: November 2008

AbstractThis paper reports the anisotropic electrical properties of a layer‐by‐layer (LBL) film composed of water‐soluble conjugated polymers and single‐walled carbon nanotubes (SWNTs). The water‐soluble poly (p‐phenylene ethynylene)s (PPEs) are capable of a strong π‐π interaction with the sidewall of SWNTs and results in a very stable PPE‐SO3/SWNTs composite in aqueous solution. Aligned LBL films were prepared by self‐assembly using the anionic PPE/SWNTs and cationic PPE on various substrates. The polarized Raman spectra exhibited the cos2α polarization dependence of the G‐band intensity between the polarization direction and the SWNTs alignment direction. The electric conductivity within the LBL films can be controlled by the deposition direction in the LBL formation.magnified image
Asymptotic regularity of solutions to Hartree–Fock equations with Coulomb potential
Authors: Flad Heinz‐Jürgen , Schneider Reinhold , Schulze Bert‐Wolfgang 
Published: November 2008

AbstractWe study the asymptotic regularity of solutions to Hartree–Fock (HF) equations for Coulomb systems. To deal with singular Coulomb potentials, Fock operators are discussed within the calculus of pseudo‐differential operators on conical manifolds. First, the non‐self‐consistent‐field case is considered, which means that the functions that enter into the nonlinear terms are not the eigenfunctions of the Fock operator itself. We introduce asymptotic regularity conditions on the functions that build up the Fock operator, which guarantee ellipticity for the local part of the Fock operator on the open stretched cone ℝ+ × S2. This proves the existence of a parametrix with a corresponding smoothing remainder from which it follows, via a bootstrap argument, that the eigenfunctions of the Fock operator again satisfy asymptotic regularity conditions. Using a fixed‐point approach based on Cancès and Le Bris analysis of the level‐shifting algorithm, we show via another bootstrap argument that the corresponding self‐consistent‐field solutions to the HF equation have the same type of asymptotic regularity. Copyright © 2008 John Wiley & Sons, Ltd.
Evidence of reduced glutamate in the frontal lobe of HIV‐seropositive patients
Authors: Sailasuta Napapon , Shriner Kimberly , Ross Brian 
Published: November 2008

AbstractNeurological complications associated with the acquired immunodeficiency syndrome, in particular, HIV‐associated dementia, continue to plague those infected. We report our finding that the concentration of brain Glu is reduced in the frontal white matter region in this condition. In addition, our data appear to absolve highly active retroviral therapy (HAART) from blame, as drug‐naïve patients were equally affected. Our findings suggest that Glu neurotransmission is abnormal and may be a key target for early interventions to reduce the later incidence of neurocognitive impairment and dementia among HIV‐seropositive patients. Copyright © 2008 John Wiley & Sons, Ltd.
Switching of vascular phenotypes within a murine breast cancer model induced by angiopoietin‐2
Authors: Reiss Yvonne , Knedla Anette , Tal Andrea O , Schmidt Mirko HH , Jugold Manfred , Kiessling Fabian , Burger Angelika M , Wolburg Hartwig , Deutsch Urban , Plate Karl H 
Published: November 2008

AbstractSustained growth of solid tumours can rely on both the formation of new and the co‐option of existing blood vessels. Current models suggest that binding of angiopoietin‐2 (Ang‐2) to its endothelial Tie2 receptor prevents receptor phosphorylation, destabilizes blood vessels, and promotes vascular permeability. In contrast, binding of angiopoietin‐1 (Ang‐1) induces Tie2 receptor activation and supports the formation of mature blood vessels covered by pericytes. Despite the intense research to decipher the role of angiopoietins during physiological neovascularization and tumour angiogenesis, a mechanistic understanding of angiopoietin function on vascular integrity and remodelling is still incomplete. We therefore assessed the vascular morphology of two mouse mammary carcinoma xenotransplants (M6378 and M6363) which differ in their natural angiopoietin expression. M6378 displayed Ang‐1 in tumour cells but no Ang‐2 in tumour endothelial cells in vivo. In contrast, M6363 tumours expressed Ang‐2 in the tumour vasculature, whereas no Ang‐1 expression was present in tumour cells. We stably transfected M6378 mouse mammary carcinoma cells with human Ang‐1 or Ang‐2 and investigated the consequences on the host vasculature, including ultrastructural morphology. Interestingly, M6378/Ang‐2 and M6363 tumours displayed a similar vascular morphology, with intratumoural haemorrhage and non‐functional and abnormal blood vessels. Pericyte loss was prominent in these tumours and was accompanied by increased endothelial cell apoptosis. Thus, overexpression of Ang‐2 converted the vascular phenotype of M6378 tumours into a phenotype similar to M6363 tumours. Our results support the hypothesis that Ang‐1/Tie2 signalling is essential for vessel stabilization and endothelial cell/pericyte interaction, and suggest that Ang‐2 is able to induce a switch of vascular phenotypes within tumours. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The interaction of cell‐penetrating peptides with lipid model systems and subsequent lipid reorganization: thermodynamic and structural characterization
Authors: Alves Isabel D. , Correia Isabelle , Jiao Chen Yu , Sachon Emmanuelle , Sagan Sandrine , Lavielle Solange , Tollin Gordon , Chassaing Gérard 
Published: November 2008

AbstractCell‐penetrating peptides (CPPs) are cationic peptides that are able to induce cellular uptake and delivery of large and hydrophilic molecules, that otherwise do not cross the plasma membrane of eukaryotic cells. Despite their potential use for gene transfer and drug delivery, the mode of action of CPPs is still mysterious. Nonetheless, the interaction with phospholipid bilayers constitutes the first step in the process. The interaction of two CPPs with distinct charge distribution, penetratin (nonamphipathic) and RL16 (a secondary amphipathic peptide with antimicrobial properties) with lipid membranes was investigated. For this purpose, we employed three independent techniques, comprising 31P‐nuclear magnetic resonance, differential scanning calorimetry (DSC), and plasmon waveguide resonance (PWR) spectroscopy. In view of the cationic nature of the peptides, their interaction and affinity for zwitterionic versus anionic lipids was investigated. Although a strong affinity was observed when negative charged lipids were present, the peptides' thermodynamic behavior on binding to zwitterionic versus anionic lipids and the induced supramolecular structure organization in those lipids was quite different. The study suggests that the amphipathic profile and charge distribution of CPPs strongly influences the perturbation mechanism of the peptide on the bilayer establishing the frontier between a pure CPP and a CPP with antimicrobial properties. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Solid phase synthesis and RNA‐binding studies of a serum‐resistant nucleo‐ε‐peptide
Authors: Roviello G. N. , Musumeci D. , Castiglione M. , Bucci E. M. , Pedone C. , Benedetti E. 
Published: November 2008

AbstractIn the present work we report the synthesis of a new Fmoc‐protected L‐lysine‐based nucleo‐amino acid suitable for the solid phase assembly and its oligomerisation to the corresponding nucleo‐ε‐peptide that we called ε‐lysPNA. The ability to bind complementary RNA and the stability in serum of this synthetic nucleo‐ε‐peptide were studied to explore its possible use in antisense or diagnostic applications. Our interest to the presented oligonucleotide analogue was also supported by the importance of ε‐peptides and other ε‐amino acid‐containing compounds in natural products with biological activity such as the poly‐ε‐lysines produced by Streptomyces albulus that possess a highly selective antimicrobial activity. Another aspect we intended to evaluate by this work is the possible prebiotic implication of these nucleopeptides, since ε‐peptides, and not α‐peptides, were mainly obtained among the other thermal prebiotic polypeptides in pyrocondensation of lysine, a diamino acid also detected in Mighei meteorite. Besides this intriguing question, all the remarkable properties emerged from the present investigation on ε‐lysPNAs encourage, without doubts, interest in the therapeutic and diagnostic potential of these bioinspired nucleopeptides. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Quantitative Structure–Activity Relationship Analysis of Some Thiourea Derivatives with Activities Against HIV‐1 (IIIB)
Authors: Li Zu‐Guang , Chen Ke‐Xian , Xie Hai‐Ying , Gao Jian‐Rong 
Published: November 2008

AbstractTwo‐dimensional (2D) and Three‐dimensional (3D) Quantitative Structure–Activity Relationship (QSAR) studies have been carried out on a series of 42 recently synthesized thiourea derivatives to find out the structural requirements of their protection of MT‐4 cells against Human Immunodeficiency Virus (HIV)‐1 (IIIB). The statistically significant 2D‐QSAR model (r2=0.897) was developed by Genetic Function Approximation (GFA) when the number of descriptors in equation was set to four, indicating descriptors of S_aaCH, Shadow_XYfrac, Lowest Unoccupied Molecular Orbital (LUMO), and Hydrogen‐Bond Acceptors (Hbond Acceptor) mainly control the bioactivity. The validation of the model was done by the full cross‐validation tests, randomization tests, and external test set prediction. Molecular Field Analysis (MFA) investigated the substitutional requirements for the favorable receptor–drug interaction and constructed the best 3D‐QSAR model using Genetic Partial Least Squares (G/PLS) method, showing that the electrostatic fields contribute significantly toward bioactivity. The results obtained by combining both methodologies give insight into the key features for designing more potent analogs against HIV‐1(IIIB).
A derivatisation and liquid chromatography/electrospray ionisation multistage mass spectrometry method for the characterisation of naphthenic acids
Authors: Smith B. E. , Rowland S. J. 
Published: November 2008

AbstractNaphthenic acids (NAs) are partially uncharacterised complex mixtures of carboxylic acids, resulting from the microbial oxidation of petroleum hydrocarbons. They are associated with the fouling of pipelines and process equipment in oil production and with corrosion in oil refineries. As by‐products of the rapidly expanding oil (tar) sands industries, NAs are also pollutants and have proved to be toxic to a range of organisms. They also have important beneficial uses as fungicides, tyre additives and, paradoxically, also in the manufacture of corrosion inhibitors. These features make the characterisation of NAs an important goal for analytical chemists. Here we describe the synthesis of amide derivatives of NAs for characterisation by liquid chromatography/electrospray ionisation multistage mass spectrometry (LC/ESI‐MSn). The method was applied to commercially available carboxylic acids, novel synthetic NAs, commercial NAs refined from crude oils, crude oil NAs and Athabasca oil sands NAs. In addition to confirming the number of alicyclic rings and length of alkyl side chain substituents (confirming information from existing methods), the MSn results provided further structural information. Most important of these was the finding that bi‐ to polycyclic acids containing ethanoate side chains, in addition to alkyl substituents, were widespread amongst the oil and oil sands NAs. The latter NAs are known end members of the β‐oxidation of NAs with even carbon number alkanoate chains. Since such NA mixtures are toxic, they should be targets for bioremediation. Bioremediation of NAs can also be monitored better by application of the methods described herein. Copyright © 2008 John Wiley & Sons, Ltd.
Mapping student understanding in chemistry: The Perspectives of Chemists
Authors: Claesgens Jennifer , Scalise Kathleen , Wilson Mark , Stacy Angelica 
Published: November 2008

AbstractPreliminary pilot studies and a field study show how a generalizable conceptual framework calibrated with item response modeling can be used to describe the development of student conceptual understanding in chemistry. ChemQuery is an assessment system that uses a framework of the key ideas in the discipline, called the Perspectives of Chemists, and criterion‐referenced analysis using item response models (item response theory (IRT)) to map student progress. It includes assessment questions, a scoring rubric, item exemplars, and a framework to describe the paths of student understanding that emerge. Integral to criterion‐referenced measurement is a focus on what is being measured: the intention of the assessment, its purpose, and the context in which it is going to be used. The Perspectives framework allows us to begin to narrate the development of understanding that occurs as students “learn'' over the course of instruction, helping to form a crosswalk among educational science standards and underscore the importance of scientific reasoning with domain knowledge. Here, we explain a framework we have investigated in chemistry and present evidence on measures of student understanding to describe the development of conceptual understanding at the high school and university levels. © 2008 Wiley Periodicals, Inc. Sci Ed 93:56–85, 2009
Gandhi's technoscience: sustainability and technology as themes of politics
Authors: Ninan Anup Sam 
Published: November 2008

AbstractBased on an in‐depth examination of the original writings of Mohandas Gandhi, spanning over 98 volumes, and the compendium of works by his associates J. C. Kumarappa and Vinoba Bhave, this article explores the technoscientific notions of the Gandhian school of thought to broaden the technology–sustainability discussions. Premised on the idea of nature, the varying nature–human definitions were crucial for Gandhians in pursuing their political activities. Positing nature methodologically as an unproblematic abstract category, Gandhians formulated, redefined and appropriated technoscientific spaces; thereby facilitating their technological choices and artefacts to embody the values of sustainability, decentralized autonomy and labour‐intensiveness. They engaged science and technology as a contextually contingent social process and integrated it into a mass political movement by identifying technoscience as a site of political action. This article adds to the STS discussions on democratization of technology, and the socially embedded nature of scientific ingenuity and multivalency of technological choices. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
Is air transport an effective tool for sustainable development?
Authors: Daley Ben 
Published: November 2008

AbstractSeveral authoritative studies indicate that air transport makes a strong, positive contribution to economic development – a contribution that far outweighs the environmental and social costs of aviation. This article investigates this benign view, analysing the assumptions upon which it is based and arguing that the relationship between air transport and economic benefits may be more complex than is commonly held. In particular, the benefits of air transport services may be highly unevenly distributed, with particular groups benefiting from air transport provision to a far greater extent than others. Hence this article poses the question of whether air transport is an effective tool for sustainable development, or whether it simply reinforces existing patterns of economic interest and political hegemony. Based on analysis of a range of key documents, some criteria are presented that could potentially be used to indicate how air transport may most effectively be used to promote sustainable development. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
Influence of electrolyte temperature on pure titanium modified by electrochemical treatment for implant
Authors: Lee Im Gi , Kim Yu Kyoung , Park Il Song , Park Ju Mi , Lee Min Ho , Bae Tae Sung , Park Charn Woon 
Published: November 2008

AbstractThis study examined the effect of electrolyte temperature on the surface characteristics of anodized pure titanium in DL‐α‐glycerophosphate (DL‐α‐GP) and calcium acetate (CA). The anodic oxide films contained a large proportion of anatase with some rutile. The relative intensity of the anatase peaks and the surface roughness increased with increasing electrolyte temperature. As the electrolyte temperature was increased, the pore size increased to 1–4 µm, and the apatite crystals became coarser and denser. The amount of calcium and phosphate adsorbed increased with increasing electrolyte temperature. The anodizing voltage reached the onset of constant voltage mode faster with decreasing electrolyte temperature. A higher voltage is essential for the electrolyte at lower temperature to reach the constant voltage mode during this initial period. Copyright © 2008 John Wiley & Sons, Ltd.
Committed carbon—upgrading existing buildings
Authors: Partridge Lester E. , Loughnane Eoin J. 
Published: November 2008

AbstractMany new buildings are designed to incorporate low carbon emission features which enhance a building's environmental performance. However, new buildings only represent a small percentage of the entire building stock. Upgrading existing buildings to meet lower carbon emission performance targets presents a huge opportunity for building owners, designers and contractors. This article outlines the methodology and strategies for reducing carbon emissions in existing buildings, and provides an example of the strategies and design processes undertaken for refurbishing a 30‐storey building in Sydney's CBD. A scope of works was developed for the example building in 2006 with the aim of reducing the base building system's annual greenhouse gas emissions from 141 to 87 kg CO2/m2. Copyright © 2008 John Wiley & Sons, Ltd.
Nanostructured Hypoeutectic Fe-B Alloy Prepared by a Self-propagating High Temperature Synthesis Combining a Rapid Cooling Technique
Authors: Fu Licai , Yang Jun , Bi Qinling , Liu Weimin 
Published: November 2008

Abstract
We have successfully synthesized bulk nanostructured Fe94.3B5.7 alloy using the one-step approach of a self-propagating high temperature synthesis (SHS) combining a rapid cooling technique. This method is convenient, low in cost, and capable of being scaled up for processing the bulk nanostructured materials. The solidification microstructure is composed of a relatively coarse, uniformly distributed dendriteto a nanostructured eutectic matrix with α-Fe(B) and t-Fe2B phases. The fine eutectic structure is disorganized, and the precipitation Fe2B is found in the α-Fe(B) phase of the eutectic. The dendrite phase has the t-Fe2B structure rather than α-Fe(B) in the Fe94.3B5.7 alloy, because the growth velocity of t-Fe2B is faster than that of the α-Fe with the deeply super-cooling degree. The coercivity (Hc) and saturation magnetization (Ms) values of the Fe94.3B5.7 alloy are 11 A/m and 1.74T, respectively. Moreover, the Fe94.3B5.7 alloy yields at 1430 MPa and fractures at 1710 MPa with a large ductility of 19.8% at compressive test.
Directly observed interaction within adolescent romantic relationships: What have we learned?
Authors: Welsh Deborah P. , Shulman Shmuel 
Published: November 2008

ABSTRACTReview and conceptual analysis of the papers in this special issue calls attention to several important methodological and conceptual issues surrounding the direct observation of adolescent romantic couples. It also provides an important new foundation of knowledge about the nature of adolescents’ romantic relationships. Connections with previous family relationships, new understandings of the distinctive nature of adolescent romantic relationships, and gender issues are clarified by this body of papers. Together, these papers move the scholarly field forward and generate new lines of questions for future investigators.
On the origin of sensory impairment and altered pain perception in Prader–Willi syndrome: A neurophysiological study
Authors: Priano Lorenzo , Miscio Giacinta , Grugni Graziano , Milano Eva , Baudo Silvia , Sellitti Luigi , Picconi Roberto , Mauro Alessandro 
Published: November 2008

ABSTRACTIntroduction: High pain threshold is a supportive diagnosis criterion for Prader–Willi syndrome (PWS), but its pathogenesis is poorly understood. In this study we investigate sensory pathways in PWS, in order to evaluate peripheral or central involvement in altered sensory perception.Methods: 14 adult PWS patients, 10 obese non‐diabetic people and 10 age‐matched controls underwent: (a) motor/sensory nerve conduction velocities at the upper and lower limbs; (b) palmar/plantar sympathetic skin response; (c) somatosensory evoked potentials from upper/lower limbs; (d) quantitative sensory testing to measure sensory threshold for vibration, warm and cold sensation, heat and cold‐induced pain and (e) blood sample analysis to evaluate glucose and insulin levels and to calculate the quantitative insulin‐sensitivity check index (QUICKI).Results: Electroneurographic examination, sympathetic skin response and somatosensory evoked potentials were all within normal ranges. In the PWS group, thermal and pain thresholds but not vibratory were significantly higher than in healthy and obese people (p<0.05). Sensory threshold did not correlate with BMI nor with QUICKI.Conclusions: Our data suggest that altered perception in PWS does not seem attributable to a peripheral nerve derangement due to metabolic factors or obesity. Impairment of the small nociceptive neurons of dorsal root ganglia or involvement of hypothalamic region may not be excluded.