bluuebunny/crossref_metadata_2025 huggingface dataset:
SOIL ORGANIC CARBON STOCK AND FRACTIONS IN RELATION TO LAND USE AND SOIL DEPTH IN THE DEGRADED SHIWALIKS HILLS OF LOWER HIMALAYAS
Authors: Debasish‐Saha  , Kukal S.S. , Bawa S.S.
Published: April 2012

The proportional differences in soil organic carbon (SOC) and its fractions under different land uses are of significance for understanding the process of aggregation and soil carbon sequestration mechanisms. A study was conducted in a mixed vegetation cover watershed with forest, grass, cultivated and eroded lands in the degraded Shiwaliks of the lower Himalayas to assess land‐use effects on profile SOC distribution and storage and to quantify the SOC fractions in water‐stable aggregates (WSA) and bulk soils. The soil samples were collected from eroded, cultivated, forest and grassland soils for the analysis of SOC fractions and aggregate stability. The SOC in eroded surface soils was lower than in less disturbed grassland, cultivated and forest soils. The surface and subsurface soils of grassland and forest lands differentially contributed to the total profile carbon stock. The SOC stock in the 1.05‐m soil profile was highest (83.5 Mg ha−1) under forest and lowest (55.6 Mg ha−1) in eroded lands. The SOC stock in the surface (0–15 cm) soil constituted 6.95, 27.6, 27 and 42.4 per cent of the total stock in the 1.05‐m profile of eroded, cultivated, forest and grassland soils, respectively. The forest soils were found to sequester 22.4 Mg ha−1 more SOC than the cultivated soils as measured in the 1.05‐m soil profiles. The differences in aggregate SOC content among the land uses were more conspicuous in bigger water‐stable macro‐aggregates (WSA > 2 mm) than in water‐stable micro‐aggregates (WSA < 0.25 mm). The SOC in micro‐aggregates (WSA < 0.25 mm) was found to be less vulnerable to changes in land use. The hot water soluble and labile carbon fractions were higher in the bulk soils of grasslands than in the individual aggregates, whereas particulate organic carbon was higher in the aggregates than in bulk soils. Copyright © 2012 John Wiley & Sons, Ltd.
Facile Fabrication of Thermo‐Responsive and Reduction‐Sensitive Polymeric Micelles for Anticancer Drug Delivery
Authors: Jiang Xulin , Li Lihua , Liu Jia , Hennink Wim E. , Zhuo Renxi
Published: April 2012

The development of thermo‐responsive and reduction‐sensitive polymeric micelles based on an amphiphilic block copolymer poly[(PEG‐MEMA)‐co‐(Boc‐Cyst‐MMAm)]‐block‐PEG (denoted PEG‐P‐SS‐HP) for the intracellular delivery of anticancer drugs is reported. PTX, as model drug, was loaded into the PEG‐P‐SS‐HP micelles with an encapsulation efficiency >90%, resulting in a high drug loading content (up to 35 wt%). The PTX‐loaded PEG‐P‐SS‐HP micelles show slow drug release in PBS and rapid release after incubation with DTT. The PTX‐loaded micelles display a better cytotoxic effect than the free drug, whereas empty micelles are found to be non‐toxic. The thermo‐responsive and reduction‐sensitive polymeric micelles described may serve as promising carriers for cytostatic drugs.

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Fine Tuning of Vesicle Assembly and Properties Using Dual Hydrophilic Triblock Copolypeptides
Authors: Rodriguez April R. , Choe Uh‐Joo , Kamei Daniel T. , Deming Timothy J.
Published: April 2012

The design, synthesis, and self‐assembly of the first dual hydrophilic triblock copolypeptide vesicles, ${\rm R}_{m}^{{\rm H}} {\rm E}_{n} {\rm L}_{o} $ and ${\rm K}_{m}^{{\rm P}} {\rm R}_{n}^{{\rm H}} {\rm L}_{o} $, is reported. Variation of the two distinct hydrophilic domains is used to tune cellular interactions without disrupting the self‐assembled structure. The aqueous self‐assemblies of these triblock copolypeptides in water are characterized using microscopy and DLS. Cell culture studies are used to evaluate cytotoxicity as well as intracellular uptake of the vesicles. The ability of polypeptides to incorporate ordered chain conformations that direct self‐assembly, combined with the facile preparation of functional, multiblock copolypeptide sequences of defined lengths, allow the design of vesicles attractive for development as drug carriers.

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An approximate Herbrand’s theorem and definable functions in metric structures
Authors: Goldbring Isaac
Published: April 2012

We develop a version of Herbrand's theorem for continuous logic and use it to prove that definable functions in infinite‐dimensional Hilbert spaces are piecewise approximable by affine functions. We obtain similar results for definable functions in Hilbert spaces expanded by a group of generic unitary operators and Hilbert spaces expanded by a generic subspace. We also show how Herbrand's theorem can be used to characterize definable functions in absolutely ubiquitous structures from classical logic.
Weak convergence of spectral shift functions for one‐dimensional Schrödinger operators
Authors: Gesztesy Fritz , Nichols Roger
Published: April 2012

We study the manner in which spectral shift functions associated with self‐adjoint one‐dimensional Schrödinger operators on the finite interval (0, R) converge in the infinite volume limit R → ∞ to the half‐line spectral shift function. Relying on a Fredholm determinant approach combined with certain measure theoretic facts, we show that prior vague convergence results in the literature in the special case of Dirichlet boundary conditions extend to the notion of weak convergence and arbitrary separated self‐adjoint boundary conditions at x = 0 and x = R.
Truncated Hamburger moment problem for an operator measure with compact support
Authors: Arlinskiĭ Yury
Published: April 2012

Given bounded selfadjoint operators \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$F_1=I_{\mathfrak N}$\end{document}, F2, …, F2n + 1 in a separable Hilbert space \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathfrak N$\end{document}, we consider the operator truncated Hamburger moment problem of finding a Herglotz‐Nevanlinna operator‐valued function M holomorphic in the neighborhood of infinity and having the form

Criteria of the solvability and uniqueness of the solution are established and a description of all solutions is obtained. Our approach is based on the Schur transformation, the Schur parameters, and the special block operator Jacobi matrices.
Are Consumer and Brand Personalities the Same?
Authors: Huang Hazel H. , Mitchell Vincent‐Wayne , Rosenaum‐Elliott Richard
Published: April 2012

Current discussions of brand personality refer to a personified brand image, that is, a brand image that can possess any attributes of consumers, rather than brand personality. From a conceptual and methodological critique of the literature, this paper applies the definition of personality to brand personality, and tests the idea using a peer‐rating methodology that focuses on each individual's perception of a brand (the brand × subject structure). The results reveal that consumers reflect their personalities by the brands they use, but the relationship between brand choice and symbolic dimensions (i.e., extraversion, agreeableness, neuroticism, and openness to experience) is much stronger than the relationship with functional dimensions (i.e., conscientiousness). Moreover, the pattern of this relationship remains consistent across symbolic and utilitarian products, which implies that consumers choose brands with similar personalities to theirs across various products. The study concludes that an abridged personality scale, based on the Big Five, can be applied to both brands and consumers. © 2012 Wiley Periodicals, Inc.
The Moderating Influence of Broad‐Scope Trust on Customer–Seller Relationships
Authors: Hansen Torben
Published: April 2012

Trust relates not only to customer trust in individual companies (i.e., narrow‐scope trust) but also to the broader business context in which customer–seller relationships may develop (i.e., broad‐scope trust [BST]). Based on two surveys comprising 1155 bank consumers and 817 insurance consumers, respectively, this study investigates the moderating influence of BST on relationships between satisfaction, narrow‐scope trust, and loyalty and also examines the direct influence of BST on these variables. The results indicate that whereas BST negatively moderates relationships between satisfaction and narrow‐scope trust and between narrow‐scope trust and loyalty, BST positively moderates the relationship between satisfaction and loyalty. In addition, it is demonstrated that BST positively influences customer satisfaction and narrow‐scope trust. © 2012 Wiley Periodicals, Inc.
Interpersonal Relationship, Service Quality, Seller Expertise: How Important Are They to Adolescent Consumers?
Authors: Wan Wendy W. N. , Luk Chung‐Leung , Fam Kim‐Shyan , Wu Peiguan , Chow Cheris W. C.
Published: April 2012

Drawing upon social capital theory and psychosocial development theory, this paper argues that a true buyer–seller relationship is a key determinant of favorable consumer behaviors for adolescent consumers of hairstylist services. Other important determinants include quality of the service delivery process (i.e., service quality as measured by the five SERVQUAL factors) and quality of the core service (in this case, the hairstylist's expertise). A survey of 350 adolescent consumers confirms these predictions. It shows that a true interpersonal relationship negatively moderates the positive effects of service quality on consumer satisfaction with, and overall assessment of the hairstylist. This negative moderating effect is labeled resource substitution benefit and the argument made that this is the fourth social capital benefit. The theoretical and practical implications of these findings are discussed. © 2012 Wiley Periodicals, Inc.
Revisiting Perceived Risk in the Context of Online Shopping: An Alternative Perspective of Decision‐Making Styles
Authors: Chang Man‐Ling , Wu Wann‐Yih
Published: April 2012

This study attempts to elaborate the consequences of perceived risk by taking the moderating effects of decision‐making style (i.e., involvement vs. heuristics) into account in the context of online shopping. The integrated model is tested repeatedly in diverse purchasing situations with different Web presentation styles and product categories. The findings indicate that perceived risk toward the Web site/product influences purchasing intention through cognition‐ and affect‐based attitudes. Moreover, the moderating effects of decision‐making style on the relationship between perceived risk and its consequences are conditional. Since perceived risk appears very crucial for promoting online shopping, the results of this study may provide an influential reference for academicians and practitioners when considering the role of perceived risk in Web site marketing. © 2012 Wiley Periodicals, Inc.
Solidified Liquid Layer Model Expands the Application Fields of Quartz Crystal Microbalance
Authors: Fu Long , Chen Yanyan , Ma Hongwei
Published: April 2012

The application of a quartz crystal microbalance (QCM) in liquid is hindered by the complexity of data analysis. Recently, a “solidified liquid layer” (SLL) model has been proposed to simplify the data analysis. Here, missing evidence to support the SLL model is provided: 1) the SLL model is responsive to the density change of the liquid environment, 2) thickness values from the SLL model (TSLL) are in agreement with values measured by ellipsometry. The SLL model predicts that a 0.18 nm change of TSLL will lead to a 1 Hz signal, which is the resolution that most commercial QCMs could easily achieve. Using the SLL model, Au–S bond breakage has been successful. Biosensor applications are also being designed according to the SLL model. It is believed that with these results, the SLL model will bring QCM back to the radar screen of scientists.
Formation of a Polypseudorotaxane via Self‐Assembly of γ‐Cyclodextrin with Poly(N‐isopropylacrylamide)
Authors: Wang Jin , Li Shuo , Ye Lin , Zhang Ai‐Ying , Feng Zeng‐Guo
Published: April 2012

A polypseudorotaxane (PPR) comprising γ‐cyclodextrin (γ‐CD) as host molecules and poly(N‐isopropylacrylamide) (PNIPAM) as a guest polymer is prepared via self‐assembly in aqueous solution. Due to the bulky pendant isopropylamide group, PNIPAM exhibits size‐selectivity toward self‐assembly with α‐, β‐, and γ‐CDs. It can fit into the cavity of γ‐CD to give rise to a PPR, but cannot pass through α‐CD and β‐CD under the same conditions. The ratio of the number of γ‐CD molecules to entrapped NIPAM repeat units is kept at 1:2.2 or 1:2.4, determined by 1H NMR spectroscopy and TGA analysis, respectively, indicating that there are more than 2 but less than 3 NIPAM repeat units included by one γ‐CD molecule. This finding opens new avenues to PPR‐based supramolecular polymers to be used as solid, stimuli‐responsive materials.
Impact of Polymer Network Inhomogeneities on the Volume Phase Transition of Thermoresponsive Microgels
Authors: Seiffert Sebastian
Published: April 2012

Thermoresponsive polymer gels exhibit pronounced swelling and deswelling upon changes in temperature, rendering them attractive for various applications. This transition has been studied extensively, but only little is known about how it is affected by nano‐ and micrometer‐scale inhomogeneities in the polymer gel network. In this work, droplet microfluidics is used to fabricate microgel particles of strongly varying inner homogeneity to study their volume phase behavior. These particles exhibit very similar equilibrium swelling and deswelling independent of their inner inhomogeneity, but the kinetics of their volume phase transition is markedly different: while gels with pronounced micrometer‐scale inhomogeneity show fast and affine deswelling, homogeneous gels shrink slowly and in multiple steps.
Pleiotropic effects of the sirtuin inhibitor sirtinol involves concentration‐dependent modulation of multiple nuclear receptor‐mediated pathways in androgen‐responsive prostate cancer cell LNCaP
Authors: Wang Thomas T.Y. , Schoene Norberta W. , Kim Eun‐Kyung , Kim Young S.
Published: April 2012

Sirtinol is a purported specific inhibitor of the nicotinamide adenine dinucleotide (NAD)‐dependent type III histone deacetylase (also known as sirtuin). Sirtinol has been used extensively to identify chemopreventive/chemotherapeutic agents that modulate the sirtuins. However, the molecular effect of sirtinol other than serving as sirtuin inhibitor in cells is less clear. The present study addressed this deficiency in the literature. Based on structural similarity with plant‐derived cancer preventive/therapeutic compounds such as 3', 3'‐diindolylmethane, resveratrol, and genistein, we hypothesized that sirtinol may act on pathways similar to that affected by these compounds in the human prostate cancer cell LNCaP. We found that treatment of LNCaP cells with sirtinol led to concentration‐dependent effects on multiple pathways. Sirtinol inhibited LNCaP cell cycle and growth that was correlated with up‐regulation of cyclin‐dependent kinase inhibitor 1A mRNA and protein levels. This effect of sirtinol may due in part to modulation of androgen, estrogen, and insulin‐like growth factor‐1 mediated pathways as sirtinol treatment led to inhibition of mRNA and protein expression of marker genes involved in these pathways. We also found sirtinol activates aryl hydrocarbon‐dependent pathways in LNCaP cells. The effects of sirtinol were observed at 25 µM, a concentration lower than Ki (38 µM) for sirtuin activity. Based on these results we reasoned that sirtinol exerts pleiotropic effects in cells and that biological effects of sirtinol may not be due solely to inhibition of sirtuin. © 2012 Wiley Periodicals, Inc.
Association of genetic variants of human telomerase with colorectal polyps and colorectal cancer risk
Authors: Hofer Philipp , Baierl Andreas , Bernhart Kathrin , Leeb Gernot , Mach Karl , Micksche Michael , Gsur Andrea
Published: April 2012

Human telomerase reverse transcriptase (TERT) gene encodes the catalytic subunit of telomerase and is located on chromosome 5p15, a genomic region which was found to be associated with multiple cancer types. But no associations with colorectal cancer (CRC) have been reported until recently. Therefore, the purpose of this study was to investigate the influence of seven single‐nucleotide polymorphisms (SNPs) of TERT on susceptibility to colorectal polyps and CRC. The study population of our ongoing colorectal cancer study of Austria (CORSA) comprised 3,842 Caucasian participants. A total of 3,264 participants was genotyped including 142 CRC cases, 492 high‐risk polyps, 837 low‐risk polyps, and 1,793 polyp‐free controls verified by colonoscopy. Genotyping was performed by TaqMan assay using genomic DNA. The impact of each SNP was estimated by multiple logistic regression analyses performed with R Version 2.11.1. None of the investigated TERT SNPs (rs2736122, rs2853676, rs2735940, rs2736098, rs2075786, rs2736100, rs4975605) were found to be associated with risk of CRC nor colonic polyps. However, the haplotype CGTATGG was associated with a significantly increased risk of high‐risk polyps (OR = 1.48, 95% CI 1.01–2.17, P = 0.043). In accordance with other studies our results suggest no major influence of the investigated TERT SNPs on CRC and colorectal polyp risk. However, relevance of telomerase in tumorigenesis of multiple malignancies demands further investigations of the 5p15 locus concerning CRC susceptibility. © 2012 Wiley Periodicals, Inc.
Functional studies of a novel Germline p53 splicing mutation identified in a patient with Li–Fraumeni‐Like syndrome
Authors: Piao Jinhua , Sakurai Naoto , Iwamoto Shotaro , Nishioka Junji , Nakatani Kaname , Komada Yoshihiro , Mizutani Shuki , Takagi Masatoshi
Published: April 2012

Most p53 mutations identified in Li–Fraumeni syndrome (LFS) are missense mutations; splicing mutations have rarely been reported. A novel splicing p53 mutation was identified in a patient with Li–Fraumeni‐like syndrome (LFL). Usually, p53 missense mutants identified in LFS and cancer cells function as dominant negative mutations interfering with wild‐type p53 function. However, the mechanism by which p53 haploinsufficiency causes carcinogenesis is not well characterized. In this study, we describe a novel splicing mutation that results in the loss‐of‐function of p53. These findings suggest a linkage between the loss‐of‐function type p53 mutation and a LFL phenotype. © 2012 Wiley Periodicals, Inc.
Civilian Response Corps Force Review: The Application of Multi‐Criteria Decision Analysis to Prioritize Skills Required for Future Diplomatic Missions
Authors: Linkov Igor , Rosoff Heather , Valverde L James , Bates Matthew E. , Trump Benjamin , Friedman Daniel , Evans Jessie , Keisler Jeffrey
Published: April 2012

Created by the State Department's Office of the Coordinator for Reconstruction and Stabilization, the Civilian Response Corps (CRC) contains a diverse pool of qualified and ready‐to‐deploy civilian professionals that support conflict prevention and response efforts in countries or regions that are at risk of, are currently in, or are transitioning from conflict or civil strife. As such, it is vital to optimize the CRC's skill groupings to maximize adaptability and responsiveness to highly uncertain and trying political conditions and crises across the globe. The nature of the CRC value proposition is such that determining which skill set compositions deliver the greatest benefit requires a multi‐faceted perspective that looks at a number of attributes and factors, both tangible and intangible. To meet these needs, an organizational decision‐making approach utilizing multi‐criteria decision analysis (MCDA) was applied to ensure that skill‐grouping allocations were determined in a logical and robust manner. The MCDA analysis allowed for a wide range of worldviews and perspectives, drawn from select members of academia and partner agencies of the CRC who provided their expert opinions on the expected demand for skill groupings commonly identified as most necessary in a civilian ‘surge’ capacity. These skills were assessed with reference to a values hierarchy of representative country scenarios, missions and sub‐missions identified by the Office of the Coordinator for Reconstruction and Stabilization. Of particular interest was the use of the MCDA method to prioritize CRC skill groupings and to help inform the Department of State's understanding of the ‘ideal’ proportion and types of civilian skills for inclusion in the CRC. Copyright © 2012 John Wiley & Sons, Ltd.
Probabilistic entropy in homogenization of the periodic fiber‐reinforced composites with random elastic parameters
Authors: Kamiński Marcin
Published: April 2012

The purpose of this elaboration is to develop an efficient method for a determination of the probabilistic entropy loss in the homogenization process of the periodic composites with random material characteristics. A definition of this entropy convenient for the Gaussian continuous distribution is adopted and implemented into the computer algebra system MAPLE. Homogenization of the fiber‐reinforced composite with randomly defined Young's moduli of the constituents is carried out in the FEM and homogenization‐oriented code based on the four‐noded plane strain elements. Probabilistic procedure has triple character and is alternatively based on the Monte Carlo simulation, on the generalized stochastic perturbation‐based analysis, and on the recently developed semi‐analytical determination of homogenized tensor using the response function method. Because of this triple usage of the probabilistic methods, it is possible to make a detailed comparison of all those techniques, especially in view of the entropy variation during the homogenization. This procedure may be linked with other homogenization techniques, also for various constitutive models and/or for the upper and lower bounds on the effective tensor components. Copyright © 2012 John Wiley & Sons, Ltd.
Cell‐based volume integration for boundary integral analysis
Authors: Koehler Matthew , Yang Ruoke , Gray L.J.
Published: April 2012

The evaluation of volume integrals that arise in boundary integral formulations for non‐homogeneous problems was considered. Using the “Galerkin vector” to represent the Green's function, the volume integral was decomposed into a boundary integral, together with a volume integral wherein the source function was everywhere zero on the boundary. This new volume integral can be evaluated using a regular grid of cells covering the domain, with all cell integrals, including partial cells at the boundary, evaluated by simple linear interpolation of vertex values. For grid vertices that lie close to the boundary, the near‐singular integrals were handled by partial analytic integration. The method employed a Galerkin approximation and was presented in terms of the three‐dimensional Poisson problem. An axisymmetric formulation was also presented, and in this setting, the solution of a nonlinear problem was considered. Copyright © 2012 John Wiley & Sons, Ltd.
Efficacy of five‐element gymnastics in glucose and lipid control in taiwanese patients with type 2 diabetes
Authors: Huang Chiu‐Ling , Tai Yen‐Kuang , Yang Yi‐Hsin , Wang Ruey‐Hsia
Published: April 2012

The purpose of this quasi‐experimental study was to determine the efficacy of Five‐Element Gymnastics (FEG) in controlling glycosylated hemoglobin (HbA1C), total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), low‐density lipoprotein cholesterol (LDL‐C), and triglycerides (TG) at the 8th and the 16th weeks of intervention for patients with type 2 diabetes in Taiwan. FEG consolidates several traditional Chinese exercises including Qigong, Xiang Gong, and martial arts with gymnastics. The experimental group (n = 31) practiced FEG at home for 16 weeks. The control group (n = 35) maintained usual activities. FEG was associated with decrease of HbA1C, TG, and LDL‐C levels at the 8th week and continuous decrease of HbA1C through the 16th week. FEG could be an exercise choice for patients with type 2 diabetes. © 2012 Wiley Periodicals, Inc. Res Nurs Health 35:419–429, 2012
Environmental Justice and Green‐Technology Adoption
Authors: Ong Paul
Published: April 2012

This paper presents an analysis of an environmental justice (EJ) program adopted by the South Coast Air Quality Management District (SCAQMD) as a part of its regulation to phase out a toxic chemical used by dry cleaners. SCAQMD provided financial incentives to switch early and gave establishments in EJ neighborhoods priority in applying for grants. Despite this pro‐EJ policy, available data show that dry cleaners in low‐income, predominantly minority, and EJ‐designated areas were less likely to be an early adopter of green technologies, and this finding holds even after accounting for firm and market characteristics. Dry cleaners in disadvantaged neighborhoods were also less likely to receive a grant to switch technology despite the district's effort to set aside half of the funding for applicants from EJ areas.
An alternative method for processing high viscosity polymers. I. Development and feasibility study
Authors: Rochman Arif , Frick Achim , Martin Peter
Published: April 2012

Ultrahigh molecular weight polymers generally exhibit very high melt viscosities. They are therefore very difficult to process and require heavy‐duty processing equipment. In some cases they cannot be processed at all using conventional melt processing techniques. In this study, a novel processing method called Thermoflow Forming (TFF) has been developed for manufacturing parts made from high viscosity polymers. The TFF process is based on the flow of polymer material in its thermoelastic state, between its glass transition and melting temperatures, by compressive flow thermoforming. The processing equipment consists of an upper and lower mold tool, which may be driven together, while its temperature is controlled through either induction heating or air cooling. Parts with both constant and varying wall thicknesses were successfully manufactured from ultrahigh molecular weight polyethylene and polytetrafluoroethylene (PTFE). Despite the significantly different wall thicknesses molded, the parts showed minimal warpage and no voids. Those made from PTFE exhibited a fibrillated morphological structure whose size and orientation depended on the material flow direction. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Varying the wetting properties of polycarbonate substrate by varying the nanomolding temperature
Authors: Huang Long‐Biao , Xu Yan , Yung Kai‐Leung , Chen Wei , Xie Yunchuan , Kong Jie
Published: April 2012

Polycarbonate (PC) nanofibers were produced using anodized aluminum oxide (AAO) template assisted nanomolding. The effects of temperature on the nanoflow were investigated. It was found that higher temperature apparently enhanced the polycarbonate nanoflow and resulted in longer nanofibers in the same duration. The surface wettabilities of the polycarbonate nanofiber coated substrates showed apparent dependency on the morphology of the surface. It was found that larger honeycomb patterns would result in higher hydrophobicity than smaller honeycomb patterns. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Investigation of the effect of ZnO nanoparticles on the thermomechanical and microbial properties of hyperbranched polyurethane‐urea hybrid composites
Authors: Jena Kishore K , Narayan Ramanuj , Raju Kothapalli V S N
Published: April 2012

Hybrid coatings of hyperbranched polyurethane‐urea (HBPUU) containing ZnO nanoparticles were prepared by mixing the hyperbranched polyurethane with the nanoparticles. The films were stored at room temperature and laboratory humidity conditions for one week to yield completely cured hybrid films. The ZnO nanoparticles were found to be well dispersed in the polymer up to 3 wt%. The structure–property relationship of various HBPUU–ZnO hybrid coatings was analysed using a Fourier transform infrared peak deconvolution technique with a Gaussian curve‐fitting procedure, while their viscoelastic, thermomechanical and surface morphology were studied using X‐ray diffraction, dynamic mechanical thermal analysis, thermogravimetric analysis, a universal testing machine, scanning electron microscopy, atomic force microscopy and contact angle instruments. The thermal stability and mechanical properties of the hybrid composite films improved with increasing ZnO content, which was believed to be due to thermal insulation in the presence of nanoparticles. Water contact angle data suggested that the hydrophobic character of the hybrid composites increased with increasing nanoparticle concentration. The antimicrobial property of the HBPUU–ZnO hybrid coatings was studied using the disc diffusion method. HBPUU–ZnO hybrid coatings showed good antimicrobial properties compared to HBPUU. Copyright © 2012 Society of Chemical Industry
Facile synthesis of 5,8‐linked quinoline‐based copolymers
Authors: Tomar Manisha , Lucas Nigel T , Kim Hun , Laquai Frédéric , Müllen Klaus , Jacob Josemon
Published: April 2012

Coupling quinoline at its 5,8‐positions provides a facile way to copolymerize quinoline with other conjugated moieties without breaking conjugation. Model compounds containing quinoline units, either at the periphery or in the core, were synthesized and one of them was characterized by X‐ray diffraction. Copolymers of quinoline and 9,9‐dialkylfluorene (R = n‐octyl or 2‐ethylhexyl) were synthesized in good yield by palladium‐catalysed Suzuki cross‐coupling. The copolymers are highly soluble in common organic solvents and gel permeation chromatography measurements against polystyrene standards showed the number‐average molecular weight to be in the range (1.02–2.06) × 104 g mol−1. Both copolymers emit in the blue region with an emission maximum centred at 435 nm. Copyright © 2012 Society of Chemical Industry
Glass transition and cooperative rearranging regions in amorphous thermoplastic nanocomposites
Authors: Greco Antonio , Gennaro Riccardo , Rizzo Michele
Published: April 2012

The aim of this work was to study the effect of nanofillers on the structural relaxation phenomena occurring in amorphous poly(ethylene‐terephthalate)/poly(cyclohexane‐dimethanol terephthalate) copolymer (PET/PCHDMT) nanocomposites in correspondence with the glass transition temperature. PET/PCHDMT nanocomposites were prepared by melt mixing with an organic modified montmorillonite at different processing temperatures. Differential scanning calorimetry analysis revealed that addition of the organic modifier alone causes a decrease of the glass transition temperature and an increase of the specific heat discontinuity. Nanocomposites showed a higher glass transition temperature and a lower specific heat discontinuity compared with samples obtained by adding organic modifier to PET/PCHDMT. Both effects were more relevant for samples processed at lower temperatures. Therefore, the glass transition temperature was studied by introducing the concept of fictive temperature and relaxation time. It was found that nanocomposites have a higher apparent activation energy and an increased size of cooperatively rearranging regions compared with neat PET/PCHDMT. Both effects are more relevant for nanocomposites processed at lower temperatures. All the discussed effects are explained by considering the enhanced confinement of PET/PCHDMT macromolecules, due to the presence of intercalated lamellae of organofiller. The efficiency of intercalation is increased by decreased processing temperature, which involves an increase of the nano‐confinement area of the polymer. Copyright © 2012 Society of Chemical Industry
Morphology and mechanical property changes in compatibilized high density polyethylene/polyamide 6 nanocomposites induced by carbon nanotubes
Authors: Xiang Fangming , Wang Yonghong , Shi Yunyun , Huang Ting , Chen Chen , Peng Ya , Wang Yong
Published: April 2012

Addition of carbon nanotubes to immiscible polymer blends with co‐continuous morphology features to improve the electrical conductivity has attracted much attention in recent years; however, less attention has been paid to the effect of carbon nanotubes on the morphology and corresponding physical properties of immiscible polymer blends with typical sea‐island morphology. In this work, therefore, functionalized multiwalled carbon nanotubes (FMWCNTs) were introduced into an immiscible high density polyethylene/polyamide 6 (HDPE/PA6) blend which was compatibilized by maleic anhydride grafted HDPE (HDPE‐MA). The distribution of FMWCNTs and the phase morphologies of the nanocomposites were characterized using scanning electron microscopy and transmission electron microscopy. The crystallization and melting behaviors of the components were analyzed by differential scanning calorimetry, which is thought to be favorable for an understanding of the distribution of FMWCNTs. It is interesting to observe that the morphology of PA6 particles is very dependent on the method of preparation of the nanocomposites. Correspondingly, FMWCNTs exhibit an apparent reinforcement effect and/or an excellent toughening effect for the compatibilized HDPE/PA6 blend, depending upon their distribution state and the variation of PA6 morphology. This work proves that FMWCNTs have a potential application in further improving the mechanical properties of compatibilized immiscible polymer blends. Copyright © 2012 Society of Chemical Industry
Synthesis and optical properties of a crosslinkable polymer system containing tricyanofuran‐based chromophores with excellent electro‐optic activity and thermal stability
Authors: Chen Zhuo , Bo Shuhui , Qiu Ling , Zhen Zhen , Liu Xinhou
Published: April 2012

Crosslinkable polymers with side‐chain systems were investigated in order to increase the content of nonlinear optical chromophores and improve the stability of oriented chromophores. A series of crosslinkable copolymers having varying concentrations of chromophores with tricyanofuran as an acceptor were successfully synthesized and characterized. The crosslinked electro‐optic (EO) polymers revealed the highest EO coefficient (r33) of 47.0 pm V−1 at 1310 nm, which was similar to r33 of uncrosslinked systems. Compared to the uncrosslinked EO polymer systems, the crosslinked ones exhibited significantly enhanced temporal stability. The results of the EO coefficients and thermal properties indicated that the crosslinking effectively improved the stability and did not influence the r33 values. Copyright © 2012 Society of Chemical Industry
Poly(arylene ether)s carrying pendant (3‐sulfonated) phenylsulfonyl groups
Authors: Kern Kimberly E , Abdellatif Mohamed , Fossum Eric
Published: April 2012

A series of poly(arylene ether)s with biphenyl units and pendant sulfonated phenylsulfonyl groups was prepared via nucleophilic aromatic substitution reactions of varying ratios of 3,5‐difluoro‐3′‐sulfonated diphenylsulfone and 4,4′‐difluorodiphenylsulfone with 4,4′‐biphenol. As such, the sulfonic acid moieties reside in the meta position of a pendant, electron‐poor phenylsulfonyl group. Mechanically robust proton‐exchange membranes with ion‐exchange capacities (IEC) ranging from 0.91 to 2.05 meq g−1 were cast from dimethylacetamide. The thermal stability of the membranes was evaluated via thermogravimetric analysis and the 5% weight losses were found to be in excess of 330 °C in air. The glass transition temperatures were determined, via differential scanning calorimetry, to range from a low of 148 to a high of 209 °C at IEC values of 0.91 and 1.79 meq g−1, respectively. The copolymer membranes reached proton conductivities as high as 142 mS cm−1 under 100% relative humidity, with relatively low water uptake values (8–32 wt%). Copyright © 2012 Society of Chemical Industry
Conducting Plasma Polymerized Polypyrrole Thin Films as Carbon Dioxide Gas Sensors
Authors: Yagüe Jose Luis , Borrós Salvador
Published: April 2012

This paper describes the production of conducting polypyrrole (PPy) thin films by plasma‐enhanced chemical vapor deposition (PECVD) and its posterior use for sensing applications of carbon dioxide (CO2). Since PECVD yields the non‐conducting form of PPy, a doping process consisting of exposure to iodine vapor is required to obtain electrically conducting samples. Differences in the chemical state and topography between the doped and undoped systems are studied and characterized to demonstrate the doping effect on the polymer. Furthermore, changes in conductivity after exposure to CO2 gas are measured to evaluate the use of these thin films as chemical sensors. The results suggest that plasma polymerized films show a good sensitivity and reproducibility in the analyte detection.

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Decontamination of Prions by the Flowing Afterglow of a Reduced‐pressure N2O2 Cold‐plasma
Authors: Elmoualij Benaïssa , Thellin Olivier , Gofflot Stéphanie , Heinen Ernst , Levif Pierre , Séguin Jacynthe , Moisan Michel , Leduc Annie , Barbeau Jean , Zorzi Willy
Published: April 2012

Transmissible spongiform encephalopathies, also called prion diseases, represent a family of neurodegenerative disorders that affect various animal species. Since the infectious forms of prions are transmissible and highly resistant to chemical and physical decontamination methods routinely used in healthcare, they represent a challenge for science, medicine, and public health/food systems. Suitable decontamination procedures have been proposed, but they are generally incompatible with the materials from which medical devices are made. In this study, we evaluate a cold gaseous‐plasma treatment, based on the outflow from a N2O2 microwave discharge, as an alternative decontamination tool against both the non‐infectious (PrPC) and infectious (PrPSc) forms of prion proteins. The efficiency of the plasma treatment on these proteins is assessed using an in vitro assay as well as an in vivo bioassay. We showed by Enzyme‐Linked Immuno‐Sorbent Assay (ELISA) that the N2O2 discharge afterglow reduces the immunoreactivity of both non‐infectious recombinant and pathogenic prion proteins deposited on polystyrene substrates. Tests done in vivo demonstrate that exposure to the cold‐plasma flowing afterglow achieves significant decontamination of stainless steel sutures inoculated with infectious forms of prions to be implanted in mice.

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Clearance of initial mucoid Pseudomonas aeruginosa in patients with cystic fibrosis
Authors: Troxler Robert Bradley , Hoover Wynton C. , Britton LaCrecia J. , Gerwin Andrea M. , Rowe Steven M.
Published: April 2012

Background

Accelerated lung function decline in cystic fibrosis (CF) is associated with mucoid Pseudomonas aeruginosa infection. Recent data suggest that mucoid P. aeruginosa may amenable to elimination from the airway. We aim to determine whether the initiation of an aggressive antibiotic eradication regimen upon initial discovery of mucoid P. aeruginosa in the CF airway could be successful in clearing the organism from the CF lung.

Methods

We performed a retrospective analysis of patients with CF who demonstrated new growth of mucoid P. aeruginosa in an airway culture between January 2003 and December 2008. The primary endpoint was clearance of mucoid P. aeruginosa, based upon the Leeds criteria, with no further growth of mucoid P. aeruginosa cultures within 12 months of the initial discovery and treatment. Factors associated with successful clearance were also evaluated.

Results

Forty‐eight of 355 patients with CF had a new diagnosis of mucoid P. aeruginosa during the study period; 15 patients underwent an eradication attempt, while 33 patients received no increase in therapy. We observed clearance of mucoid P. aeruginosa in 73.3% of patients undergoing an eradication attempt, whereas 36.6% of those that did not undergo attempted eradication cleared the organism at 1 year (P < 0.05). Prolonged mucoid P. aeruginosa airway clearance (>24 months) for mucoid P. aeruginosa was seen in 60.0% in subjects undergoing eradication compared to 21.2% (P = 0.02) in control patients. At the study conclusion, lung function was greater in subjects who underwent an eradication attempt than in patients who did not undergo an eradication attempt (FEV1%: 91.7% vs. 75.0%, P = 0.04).

Conclusions

Clearance of initial mucoid P. aeruginosa from the airways of select patients with CF is possible with current antibiotic regimens, and the attempt may be associated with improved lung function. Pediatr Pulmonol. 2012. 47:1113–1122. © 2012 Wiley Periodicals, Inc.
Theoretical study on the deglycosylation mechanism of rice BGlu1 β‐glucosidase
Authors: Wang Jinhu , Hou Qianqian , Sheng Xiang , Gao Jun , Liu Yongjun , Liu Chengbu
Published: April 2012

It is proposed that the catalysis of GH1 enzymes follows a double‐displacement mechanism involving a glycosylation and a deglycosylation steps. In this article, the deglycosylation step was studied using quantum mechanical/molecular mechanical (QM/MM) approach. The calculation results reveal that the nucleophilic water (Wat1) attacks to the anomeric C1, and the deglycosylation step experiences a barrier of 21.4 kcal/mol from the glycosyl‐enzyme intermediate to the hydrolysis product, in which an oxocarbenium cation‐like transition state (TS) is formed. At the TS, the covalent glycosyl‐enzyme bond is almost broken (distance of 2.45 Å), and the new covalent bond between the attacking oxygen of the water molecule and C1 is basically established (length of 2.14 Å). In addition, a short hydrogen bridge is observed between the nucleophilic E386 and the C2OH of sugar ring (distance of 1.94 Å) at the TS, which facilitates the ring changing from a chair form to half‐chair form, and stabilizes the oxocarbenium cation‐like TS. © 2013 Wiley Periodicals, Inc.
Supervised Bayesian latent class models for high‐dimensional data
Authors: Desantis Stacia M. , Andrés Houseman E. , Coull Brent A. , Nutt Catherine L. , Betensky Rebecca A.
Published: April 2012

High‐grade gliomas are the most common primary brain tumors in adults and are typically diagnosed using histopathology. However, these diagnostic categories are highly heterogeneous and do not always correlate well with survival. In an attempt to refine these diagnoses, we make several immunohistochemical measurements of YKL‐40, a gene previously shown to be differentially expressed between diagnostic groups. We propose two latent class models for classification and variable selection in the presence of high‐dimensional binary data, fit by using Bayesian Markov chain Monte Carlo techniques. Penalization and model selection are incorporated in this setting via prior distributions on the unknown parameters. The methods provide valid parameter estimates under conditions in which standard supervised latent class models do not, and outperform two‐stage approaches to variable selection and parameter estimation in a variety of settings. We study the properties of these methods in simulations, and apply these methodologies to the glioma study for which identifiable three‐class parameter estimates cannot be obtained without penalization. With penalization, the resulting latent classes correlate well with clinical tumor grade and offer additional information on survival prognosis that is not captured by clinical diagnosis alone. The inclusion of YKL‐40 features also increases the precision of survival estimates. Fitting models with and without YKL‐40 highlights a subgroup of patients who have glioblastoma (GBM) diagnosis but appear to have better prognosis than the typical GBM patient. Copyright © 2012 John Wiley & Sons, Ltd.
A simulation study of finite‐sample properties of marginal structural Cox proportional hazards models
Authors: Westreich Daniel , Cole Stephen R. , Schisterman Enrique F. , Platt Robert W.
Published: April 2012

Motivated by a previously published study of HIV treatment, we simulated data subject to time‐varying confounding affected by prior treatment to examine some finite‐sample properties of marginal structural Cox proportional hazards models. We compared (a) unadjusted, (b) regression‐adjusted, (c) unstabilized, and (d) stabilized marginal structural (inverse probability‐of‐treatment [IPT] weighted) model estimators of effect in terms of bias, standard error, root mean squared error (MSE), and 95% confidence limit coverage over a range of research scenarios, including relatively small sample sizes and 10 study assessments. In the base‐case scenario resembling the motivating example, where the true hazard ratio was 0.5, both IPT‐weighted analyses were unbiased, whereas crude and adjusted analyses showed substantial bias towards and across the null. Stabilized IPT‐weighted analyses remained unbiased across a range of scenarios, including relatively small sample size; however, the standard error was generally smaller in crude and adjusted models. In many cases, unstabilized weighted analysis showed a substantial increase in standard error compared with other approaches. Root MSE was smallest in the IPT‐weighted analyses for the base‐case scenario. In situations where time‐varying confounding affected by prior treatment was absent, IPT‐weighted analyses were less precise and therefore had greater root MSE compared with adjusted analyses. The 95% confidence limit coverage was close to nominal for all stabilized IPT‐weighted but poor in crude, adjusted, and unstabilized IPT‐weighted analysis. Under realistic scenarios, marginal structural Cox proportional hazards models performed according to expectations based on large‐sample theory and provided accurate estimates of the hazard ratio. Copyright © 2012 John Wiley & Sons, Ltd.
A novel Phase I/IIa design for early phase oncology studies and its application in the evaluation of MK‐0752 in pancreatic cancer
Authors: Whitehead John , Thygesen Helene , Jaki Thomas , Davies Scot , Halford Sarah , Turner Helen , Cook Natalie , Jodrell Duncan
Published: April 2012

The Cancer Research UK study CR0720‐11 is a trial to determine the tolerability and effect on survival of using two agents in combination in patients with advanced pancreatic cancer. In particular, the trial is designed first to identify the most suitable combination of doses of the two agents in terms of the incidence of dose‐limiting toxicities. Then, the survival of all patients who have received that dose combination in the study so far, together with additional patients assigned to that dose combination to ensure that the total number is sufficient, will be analysed. If the survival outcomes show promise, then a definitive randomised study of that dose combination will be recommended. The first two patients in the trial will be treated with the lowest doses of each agent in combination. An adaptive Bayesian procedure based only on monotonicity constraints concerning the risks of toxicity at different dose levels will then be used to suggest dose combinations for subsequent patients. The survival analysis will concern only patients who received the chosen dose combination, and will compare observed mortality with that expected from an exponential model based on the known survival rates associated with current treatment. In this paper, the Bayesian dose‐finding procedure is described and illustrated, and its properties are evaluated through simulation. Computation of the appropriate sample size for the survival investigation is also discussed. Copyright © 2012 John Wiley & Sons, Ltd.