bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental stress cracking: A review
Authors: Robeson Lloyd M.
Published: August 2012

Environmental stress failure of polymers (specifically glassy thermoplastics) is a major failure mode in application end use. The environmental stress failure discussion will primarily be limited to non‐reactive environments. Crystalline polymers and even lightly crosslinked polymers can exhibit similar failure to glassy polymers but often require a much higher external applied stress. The mechanisms of environmental stress cracking proposed in the literature will be discussed in detail along with testing methods commonly employed. Approaches to resolve environmental stress failure have limited discussion in the open literature although a significant number of references can be found in the patent literature. Polymer blend approaches, fiberglass reinforcement, and impact modification are areas where industry has solved the environmental stress failure problems. An additional unique mode of failure with water exposure in glassy engineering polymers yielding microcavity formation will also be discussed. Environmental stress failure is an area of considerable concern to the utilization of polymers in a myriad of applications and the unsolved problems existing in the area will be detailed suggesting the need for additional research attention. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
The tensile force oscillation of polycarbonate at elevated temperatures
Authors: Chiang Donyau , Tsai Meng‐Leung , Lee Sanboh
Published: August 2012

Tensile testing of polycarbonate (PC) with and without gamma‐ray irradiation at elevated temperatures was investigated. Two deformation mechanisms, the shear bands at low temperatures and the craze formation at high temperatures accompanied with force oscillation, were responsible for the deformation. The tensile force oscillation was observed during the tensile testing in air, but not in water or oil. This difference is attributed to the periodic variation in the elastic modulus of PC, caused by local temperature change during the deformation process. Note that air is a poor medium for heat conduction, whereas water and oil are good conductors. In addition to the test environment, the effect of the crosshead speed on the force oscillation was also investigated. The oscillation was preferably observed at lower crosshead speeds within the testing range, and was more pronounced for the irradiated specimens. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
On the thermodynamics of solid solutions of polymer and salt
Authors: Chan Chin Han , Kammer Hans‐Werner , Sim Lai Har , Nasir N.H. Abdul , Winie Tan
Published: August 2012

Solid solutions of poly(ethylene oxide) of different molecular masses (Mη from 6 × 105 to 4 × 106 g mol−1) and lithium perchlorate (LiClO4) were prepared by solution casting method. Salt concentrations of solutions vary between around 2 and 13 wt%. Thermodynamic properties of these solutions are reported in the range of low salt content. The solutions represent two‐phase systems mostly not in equilibrium at room temperature. They consist of neat crystalline PEO and an amorphous mixture of salt and polymer. Crystallinity of PEO in salt solutions stays constant with increasing salt content and is independent of molecular mass. Crystallinities serve determining share and composition of the amorphous phase. Glass transition temperature increases linearly with salt content in the amorphous phase. Depression of equilibrium melting points by addition of salt provides activity coefficients in solutions and allows for estimation of degrees of dissociation. Rate of crystallization of poly(ethylene oxide) depends exponentially on inverse undercooling. In that way, it is also coined by equilibrium melting point depression. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Molecular simulations of poly(2,5‐benzimidazole): Effect of water concentration, phosphoric acid doping, and temperature on hydrogen bonding and vehicular diffusion
Authors: Li Shuo , Fried J.R. , Colebrook John
Published: August 2012

Results of atomistic simulations of neat, hydrated, and phosphoric acid (PA)‐doped poly(2,5‐benzimidazole) (ABPBI) are reported in this article, with an emphasis on the effect of water concentration, PA‐doping level, and temperature on the hydrogen bond network and vehicular diffusion. Analysis of radial distribution functions indicates that varying water concentrations and PA‐doping levels does not have a significant effect on hydrogen bond lengths; however, high temperature causes hydrogen bond lengths to increase reflecting lower bond strength. Calculations of the number of hydrogen bonds indicate those involving PA increase with PA‐doping level, decrease with increasing temperature, and increase with decreasing water content. Sorption calculations using Grand Canonical Monte Carlo indicate the number of water molecules absorbed per 100 ABPBI repeat units is 141.5 at 298 K, in agreement with the experimental value. Vehicular diffusion coefficients in PA‐doped ABPBI decrease in the order: water > PA > ABPBI. Specifically, the vehicular diffusion of PA increases with PA‐doping level, temperature, and water content. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Preparation and release of avermectin‐loaded cellulose acetate ultrafinefibers
Authors: Zhao Dongmei , Zhang Yanhong , Lv Lili , Li Jian
Published: August 2012

In this study, avermectin (AVM) was successfully dispersed in a cellulose acetate (CA) solution. CA/AVM composite fibers were fabricated by electrospinning the blending solution containing different amounts of AVM. Further investigation indicated that the composite fibers showed continuously changed morphologies with the concentration of AVM increasing. The electrospun fibers were characterized by field emission scanning electron microscope, X‐ray diffraction, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. The release behavior of the composite fibers was studied at pH = 7.4 and buffer media at 27°C and the amounts of AVM at different release steps were determined by high performance liquid chromatography analysis. Furthermore, AVM release from the CA/AVM samples showed two stages‐initial fast and later slow release. The two stages supplied a continuous release to achieve the effective utilization of AVM. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Influence of nanoclay‐carbon black hybrid fillers on cure and properties of natural rubber compounds
Authors: Sapkota Janak , Poikelispää Minna , Das Amit , Dierkes Wilma , Vuorinen Jyrki
Published: August 2012

The influence of organically modified nanoclay‐carbon black (CB) hybrid filler on the curing behavior of natural rubber (NR) was explored in this investigation. Here an effort was paid to understand the curing kinetics of organomodified nanoclay filled rubber compounds. On the basis of two different types of modified clay, NR nanocomposites were prepared and cured by a conventional vulcanization system. A faster curing rate and lower torque values were found when the modification was done by quaternary ammonium compounds. The activation energy of the rubber curing process decreased with the incorporation of nanoclay. In addition, it was revealed that the quaternary ammonium compounds used as modifier in the clay show a plasticization effect. Additionally, X‐ray diffraction studies indicated, that the basal spacing of the clay minerals was increased in both cases after incorporation in the rubber matrix. The dynamic mechanical analysis using a strain sweep mode showed that the Payne effect decreases because of an improved dispersion of CB induced by the presence of nanoclay. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Flow and thermally induced birefringence in gas‐assisted tubular injection moldings: Simulation and experiment
Authors: Carrillo Antonio J. , Isayev A.I.
Published: August 2012

Various components of birefringence in polystyrene (PS) and polycarbonate (PC) tubular moldings, obtained by gas‐assisted injection molding (GAIM), are measured and simulated considering both flow‐ and thermally induced stresses. The flow‐ and thermally induced stresses are calculated using nonlinear and linear viscoelastic theories, respectively, based on the flow and temperature histories that the polymer experiences during the GAIM cycle. Flow‐induced birefringence components are calculated from flow stresses using the stress optical rule, while thermally induced birefringence components are calculated from thermal stresses using a photoviscoelastic model. The simulated total residual birefringence takes into account the contributions of both flow‐ and thermally induced birefringence generated during the melt injection, gas injection, and cooling stages of GAIM. The simulated results are in better agreement with the measured birefringence in PS moldings than in PC moldings. Considering both thermal and flow birefringence, simulations provides a better description of the experimental results indicating that, in GAIM moldings, the birefringence near the mold was caused mainly by flow stresses while that located towards the polymer/gas interface was caused mainly by thermal stresses. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
‘It's all bad news’: the first 3 months following a diagnosis of malignant pleural mesothelioma
Authors: Arber Anne , Spencer Lesley
Published: August 2012

Objective

This study explores patient's experience during the first 3 months following a diagnosis of malignant pleural mesothelioma.

Methods

This study uses a grounded theory approach with semi‐structured, face‐to‐face interviews with 10 patients during the first 3 months following diagnosis.

Results

The key concept that emerged from the data was this: Uncertainty and lack of control leading to emotional, physical and psychosocial distress. Three themes informed the key concept: ‘ it's all bad news’, ‘good and bad days’ and strategies of amelioration. Patients worked with a short‐term perspective on their illness but worried about the long‐term outcome and the speed of their deterioration.

Conclusions

Patients receive insufficient psychosocial support during the first 3 months following diagnosis. An early palliative care referral would improve support and referral strategies during the first 3 months of the disease. Copyright © 2012 John Wiley & Sons, Ltd.
Effects of Oligomeric Grape Seed Proanthocyanidins on Heart, Aorta, Kidney in DOCA‐Salt Mice: Role of Oxidative Stress
Authors: Wang Xing‐hui , Huang Ling‐ling , Yu Ting‐ting , Zhu Jin‐hang , Shen Bing , Zhang Ye , Wang Hong‐zhi , Gao Shan
Published: August 2012

Growing experimental and clinical data highlights the important roles of increased reactive oxygen species production in cardiovascular remodeling (CR). Oligomeric grape seed proanthocyanidins (GSPs) have been shown to be potent antioxidants and free radical scavengers. Mice were treated with DOCA‐salt to induce CR and were given distilled water or oligomeric GSPs for 4 weeks. The heart weight (HW) index and kidney weight (KW) index were expressed as heart weight/body weight (HW/BW) and kidney weight/body weight (KW/BW); the histological changes were investigated by hematoxylin and eosin and Van Gieson staining.The endothelial‐dependent vasodilation function induced by acetylcholine was investigated in isolated thoracic aorta ring. Colorimetric analysis was used to assay superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and nitric oxide (NO) content in serum and hydroxyproline content in cardiac tissue. Administration of GSPs markedly alleviated the elevation of HW/BW ratio, KW/BW ratio and cross‐sectional area of cardiomyocytes, decreased collagen deposition in heart and attenuated histopathology injury, and improves endothelial‐dependent aorta ring relaxation in vitro accompany by increasing of NO content in serum. Meanwhile, treatment with GSPs significantly ameliorated oxidative stress via increasing SOD activities and decreasing MDA formation. These findings suggest that administration of GSPs has the potential to attenuate DOCA‐salt induced CR and KH and preserve NO activity and endothelial function, which mechanism may contribute to its antioxidant characteristic, at least in part. Copyright © 2012 John Wiley & Sons, Ltd.
Central Nervous System Activities of Hypericum origanifolium Extract via GABAergic and Opioidergic Mechanisms
Authors: Yaşar Şahin Nuri , Can Özgür Devrim , Öztürk Nilgün , Sagratini Gianni , Ricciutelli Massimo , Vittori Sauro , Maggi Filippo
Published: August 2012

Pharmacological effects of hydroalcoholic extract prepared from Hypericum origanifolium Willd. (Guttiferae) on behavioral parameters and pain perceptions of mice were investigated in this study. Depression, anxiety, spontaneous locomotor activity, and motor coordination parameters of mice were assessed by modified forced swimming, hole board, activity cage, and rota‐rod tests, respectively. In addition, antinociceptive effect was evaluated by performing hot‐plate, tail‐clip, and formalin tests. Reboxetine (20 mg/kg), diazepam (1 mg/kg), and morphine (10 mg/kg) were used as reference antidepressant, anxiolytic, and analgesic drugs, respectively. Phytochemical analyses exhibited that chlorogenic acid (2317.12 ppm) and rutin (2108.79 ppm) were the main phenolic compounds in the H. origanifolium extract. The extract (50, 100, and 250 mg/kg) induced significant antidepressant, anxiolytic, and antinociceptive activities following the acute administrations. Anxiolytic effect was antagonized by flumazenil (a benzodiazepine receptor antagonist, 2.5 mg/kg, i.p.) pre‐treatment, which indicated the participation of GABA(A)‐benzodiazepine receptor complex in the activity. Moreover, centrally and peripherally mediated antinociception reversed by naloxone (a non‐selective opioid receptor antagonist, 5 mg/kg, i.p.) pre‐treatment, indicating the involvement of opioid system in the pharmacological action. These findings are the first to indicate the pharmacological effects of the H. origanifolium extract on the emotional state and pain perceptions of mice. Copyright © 2012 John Wiley & Sons, Ltd.
Pseudolaric Acid B Induces Caspase‐Dependent Apoptosis and Autophagic Cell Death in Prostate Cancer Cells
Authors: Tong Jing , Yin Shutao , Dong Yinhui , Guo Xiao , Fan Lihong , Ye Min , Hu Hongbo
Published: August 2012

Previous studies have shown that Pseudolaric acid B (PAB), a medicinal plant‐derived terpenoid, is a promising chemopreventive or therapeutic agent against various types of cancer. However, less is known regarding its activity against prostate cancer. The objective of the current study is designed to determine the anti‐prostate cancer effects of PAB. We demonstrated here that PAB was highly effective against both androgen‐dependent (LNCaP) and androgen‐independent prostate cancer cells (PC‐3 and DU145) through the mechanisms involved in induction of G2/M cell cycle arrest, caspase‐dependent apoptosis and autophagic cell death. Furthermore, PAB can greatly sensitize these two aggressive androgen‐independent prostate cancer cells to ABT‐737‐induced cytotoxicity. Our findings suggest that PAB holds excellent potential as either novel chemopreventive agent or enhancer of therapeutic drug against prostate cancer. Copyright © 2012 John Wiley & Sons, Ltd.
Cinnamophilin Isolated from Cinnamomum philippinense Protects against Collagen Degradation in Human Chondrocytes
Authors: Lu Yung‐Chang , Hsiao George , Lin Kuan‐Hung , Hsieh Ming‐Shium , Jayakumar Thanasekaran , Wu Tian‐Shung , Sheu Joen‐Rong
Published: August 2012

To investigate the therapeutic potential of naturally occurring cinnamophilin against cartilage degradation and its action mechanisms, its effects on matrix metalloproteinase (MMP)‐1 and −13 induction were examined in the human SW1353 chondrocytic cell line. Human chondrocytes (SW1353) were stimulated with interleukin (IL)‐1β, and then mitogen‐activated protein kinase (MAPK) and c‐Jun activations, inhibitory κB‐α (IκB‐α) degradation, and MMP‐1, and 13 expressions were assayed by a Western blot analysis. Cinnamophilin strongly inhibited MMP‐1 and −13 induction in IL‐1β‐treated (30 ng/mL) SW1353 cells in a concentration‐dependent manner, and it also reduced MAPK family members including extracellular signal‐regulated kinase (ERK), p38 MAPKs, and c‐Jun N‐terminal kinase. Moreover, nuclear factor (NF)‐κB signaling activation through IκB‐α degradation, IκB kinase (IKK)‐α/β, and p‐65 phosphorylation was restored by cinnamophilin upon IL‐1β stimulation. Importantly, results showed that IL‐1β‐induced activation of phosphorylated (p)‐c‐Jun in chondrocytes was significantly inhibited by cinnamophilin. These results indicate that cinnamophilin inhibited MMP‐1 and −13 expressions in IL‐1β‐treated chondrocytes through either NF‐κB or ERK/p38 MAPK downregulation and/or suppressing p‐c‐Jun pathways. Furthermore, these findings suggest that cinnamophilin may have the potential for chondroprotection against collagen matrix breakdown in cartilage of diseased tissues such as those found in arthritic disorders. Copyright © 2012 John Wiley & Sons, Ltd.
Effects of Penta‐O‐galloyl‐β‐D‐glucose on Human Neutrophil Function: significant Down‐Regulation of L‐selectin Expression
Authors: Kiss Anna K. , Filipek Agnieszka , Żyżyńska‐Granica Barbara , Naruszewicz Marek
Published: August 2012

Penta‐O‐galloyl‐β‐D‐glucose (PGG) occurrs in high concentrations in medicinal herbs such as Rhus chinensis, Paeonia suffruticosa, Acer truncatum and Terminalia chebula, which demonstrate anti‐inflammatory activity. We investigated the effect of PGG on stimulated and non‐stimulated neutrophils in processes which included reactive oxygen species generation (ROS), metalloproteinase‐9 and interleukin‐8 secretion (IL‐8), β2 integrin (CD11b) and L‐selectin (CD62L) expression and apoptosis. In concentrations of 5 μM–20 μM, PGG demonstrated statistically significant inhibition of ROS generation, IL‐8 secretion and β2 integrin expression in stimulated neutrophils. The inhibition of L‐selectin expression by PGG resulted in prevention in neutrophils’ endothelial attachment. The result obtained may explain the anti‐inflammatory activity of this compound and underline the contribution of PGG in the activity of PGG rich plant extracts. Copyright © 2012 John Wiley & Sons, Ltd.
Irregular Shaped, Assumably Semi‐Crystalline Calciumphosphate Platelet Deposition at the Mineralization Front of Rabbit Femur Osteotomy: A HR‐TEM Study
Authors: Grüner Daniel , Lips Katrin S. , Heiss Christian , Schnettler Reinhard , Kollmann Theresa , Simon Paul , Kniep Rüdiger
Published: August 2012

Although bone minerals have been widely studied by various techniques in previous studies, crystal structures, morphology of bone minerals and its building pathway remained still controversy. In this work, the ultrastructure of the mineralization front of rabbit femur has been studied by conventional and high‐resolution (HR) transmission electron microscopy (TEM). In order to induce a healing and demineralization process the animals were subjected to a standardized osteotomy stabilized with titan screws and sonic pins. After 84 days follow‐up time the newly build bone was investigated. The mineralization front of rabbit femur osteotomy contains partly mineralized collagen fibrils with a pronounced striped pattern together with a large number of agglomerated apatite platelets. The striation is caused by mineralization in the hole zones of the collagen fibrils, corresponding to the early stage of mineralization. In the TEM micrographs, the mineralization zone appears denser and compact when compared with fully mineralized bone, although most of the collagen fibrils are completely mineralized in the latter (higher concentration of interfibrillar apatite platelets within the mineralization zone). In bone some partly mineralized collagen fibrils are also observed, revealing the same arrangement, regular shape, and size of apatite platelets as collagen fibrils in the mineralization zone. Apatite platelets with irregular shapes are observed at the vortex‐shaped outer boundary of the mineralization zone, i.e. at the interfaces with nonmineralized collagen or osteoblasts. HR TEM micrographs reveal that the platelets are assumably semicrystalline and that within the platelet nanocrystalline domains of apatite are embedded in an amorphous calciumphosphate matrix. SCANNING 35: 169‐182, 2013. © 2012 Wiley Periodicals, Inc.
Detection of micro‐ and nano‐particles in animal cells by ToF‐SIMS 3D analysis
Authors: Hagenhoff Birgit , Breitenstein Daniel , Tallarek Elke , Möllers Rudolf , Niehuis Ewald , Sperber Michaela , Goricnik Barbara , Wegener Joachim
Published: August 2012

The present study describes the detection and localization of silica particles with diameters between 2 µm and 150 nm within the cytoplasm of mammalian cells by means of ToF‐SIMS 3D analysis. The particles were selected as model objects for non‐luminescent, unlabeled particles that are hard to localize by other experimental approaches. ToF‐SIMS analysis proved the uptake of the particles into the cell body, provided images of their distribution around the cell nucleus and indications that the cell membranes are undulated by the µm‐sized particles beneath the membrane. Two ion sources (Cs+ and O2+) were applied for sputtering the organic material and expose deeper sections of the cells. The resulting images are presented and compared. Copyright © 2012 John Wiley & Sons, Ltd.
Improving the reporting of randomised trials: the CONSORT Statement and beyond
Authors: Altman Douglas G. , Moher David , Schulz Kenneth F.
Published: August 2012

An extensive and growing number of reviews of the published literature demonstrate that health research publications have frequent deficiencies. Of particular concern are poor reports of randomised trials, which make it difficult or impossible for readers to assess how the research was conducted, to evaluate the reliability of the findings, or to place them in the context of existing research evidence. As a result, published reports of trials often cannot be used by clinicians to inform patient care or to inform public health policy, and the data cannot be included in systematic reviews. Reporting guidelines are designed to identify the key information that researchers should include in a report of their research. We describe the history of reporting guidelines for randomised trials culminating in the CONSORT Statement in 1996. We detail the subsequent development and extension of CONSORT and consider related initiatives aimed at improving the reliability of the medical research literature. Copyright © 2012 John Wiley & Sons, Ltd.
Dynamic semiparametric Bayesian models for genetic mapping of complex trait with irregular longitudinal data
Authors: Das Kiranmoy , Li Jiahan , Fu Guifang , Wang Zhong , Li Runze , Wu Rongling
Published: August 2012

Many phenomena of fundamental importance to biology and biomedicine arise as a dynamic curve, such as organ growth and HIV dynamics. The genetic mapping of these traits is challenged by longitudinal variables measured at irregular and possibly subject‐specific time points, in which case nonnegative definiteness of the estimated covariance matrix needs to be guaranteed. We present a semiparametric approach for genetic mapping within the mixture‐model setting by jointly modeling mean and covariance structures for irregular longitudinal data. Penalized spline is used to model the mean functions of individual quantitative trait locus (QTL) genotypes as latent variables, whereas an extended generalized linear model is used to approximate the covariance matrix. The parameters for modeling the mean–covariances are estimated by MCMC, using the Gibbs sampler and the Metropolis–Hastings algorithm. We derive the full conditional distributions for the mean and covariance parameters and compute Bayes factors to test the hypothesis about the existence of significant QTLs. We used the model to screen the existence of specific QTLs for age‐specific change of body mass index with a sparse longitudinal data set. The new model provides powerful means for broadening the application of genetic mapping to reveal the genetic control of dynamic traits. Copyright © 2012 John Wiley & Sons, Ltd.
Superchain procedures in clinical trials with multiple objectives
Authors: Kordzakhia George , Dmitrienko Alex
Published: August 2012

This paper introduces a new class of multiple testing procedures for addressing multiplicity problems arising in clinical trials with multiple objectives grouped into families. The families may correspond to equally important sets of objectives (co‐primary endpoints) or ordered sets of objectives (primary and secondary endpoints). The procedures, termed superchain procedures, serve as an extension of several classes of other multiple testing procedures, including chain procedures and parallel gatekeeping procedures. Superchain procedures exhibit several desirable features, including flexible decision rules that can be tailored to a broad class of win criteria in confirmatory clinical trials. Additionally, superchain procedures enable the trial's sponsor to efficiently incorporate available distributional information to improve overall power. Finally, superchain procedures rely on straightforward testing algorithms, which facilitates their development. We illustrate the new methodology by using clinical trial examples with two and three families of objectives. Copyright © 2012 John Wiley & Sons, Ltd.
Local influence measure of zero‐inflated generalized Poisson mixture regression models
Authors: Chen Xue‐Dong , Fu Ying‐Zi , Wang Xue‐Ren
Published: August 2012

In many practical applications, count data often exhibit greater or less variability than allowed by the equality of mean and variance, referred to as overdispersion/underdispersion, and there are several reasons that may lead to the overdispersion/underdispersion such as zero inflation and mixture. Moreover, if the count data are distributed as a generalized Poisson or a negative binomial distribution that accommodates extra variation not explained by a simple Poisson or a binomial model, then the dispersion occurs too. In this paper, we deal with a class of two‐component zero‐inflated generalized Poisson mixture regression models to fit such data and propose a local influence measure procedure for model comparison and statistical diagnostics. At first, we formally develop a general model framework that unifies zero inflation, mixture as well as overdispersion/underdispersion simultaneously, and then we mainly investigate two types of perturbation schemes, the global and individual perturbation schemes, for perturbing various model assumptions and detecting influential observations. Also, we obtain the corresponding local influence measures. Our method is novel for count data analysis and can be used to explore these essential issues such as zero inflation, mixture, and dispersion related to zero‐inflated generalized Poisson mixture models. On the basis of the results of model comparison, we could further conduct the sensitivity analysis of perturbation as well as hypothesis test with more accuracy. Finally, we employ here a simulation study and a real example to illustrate the proposed local influence measures. Copyright © 2012 John Wiley & Sons, Ltd.
Comparability of critical quality attributes for establishing biosimilarity
Authors: Liao Jason J.Z. , Darken Patrick F.
Published: August 2012

To develop a biosimilar product, it is essential to demonstrate the biosimilarity between the proposed biosimilar product and the reference product first in terms of quality in a stepwise approach that can then help inform the extent of safety and efficacy data that will be required to establish biosimilarity. These comparability studies should have direct side‐by‐side comparisons of the test and the reference products. In this paper, we develop a statistical method for unpaired head‐to‐head quality attribute comparisons. The method uses a plausibility interval derived from comparing the reference against the reference itself as the goalpost for claiming comparability. The idea behind this is that any observed difference between the reference and the reference itself should be considered as the random noise and as a part of the variability. We illustrate the performance of the proposed method by using simulation and real data sets. Copyright © 2012 John Wiley & Sons, Ltd.
Comments on the FDA draft guidance on biosimilar products
Authors: Chow Shein‐Chung , Endrenyi Laszlo , Lachenbruch Peter A.
Published: August 2012

The Food and Drug Administration issued on February 9, 2012, drafts of three new guidance documents about the demonstration of biosimilarity. One of these deals with scientific considerations. It suggests, among others, that demonstration of biosimilarity be developed by a stepwise (step‐by‐step) approach and that it be assessed by considering the totality of the evidence. This communication provides comments on some scientific factors and issues that still remain unanswered or unsolved. They include the question ‘how similar is considered to be highly similar?’ considerations of criteria for and the degree of biosimilarity; alternatives of study design and sample size requirements; statistical methods for achieving the totality of the evidence needed for biosimilarity; and methods needed for the assessment of drug interchangeability. It is anticipated that the comments will assist the revision of the guidance documents. Copyright © 2012 John Wiley & Sons, Ltd.
A semiparametric recurrent events model with time‐varying coefficients
Authors: Yu Zhangsheng , Liu Lei , Bravata Dawn M. , Williams Linda S. , Tepper Robert S.
Published: August 2012

We consider a recurrent events model with time‐varying coefficients motivated by two clinical applications. We use a random effects (Gaussian frailty) model to describe the intensity of recurrent events. The model can accommodate both time‐varying and time‐constant coefficients. We use the penalized spline method to estimate the time‐varying coefficients. We use Laplace approximation to evaluate the penalized likelihood without a closed form. We estimate the smoothing parameters in a similar way to variance components. We conduct simulations to evaluate the performance of the estimates for both time‐varying and time‐independent coefficients. We apply this method to analyze two data sets: a stroke study and a child wheeze study. Copyright © 2012 John Wiley & Sons, Ltd.
A mechanistic breast cancer survival modelling through the axillary lymph node chain
Authors: Cobre Juliana , Castro Perdoná Gleici S. , Peria Fernanda M. , Louzada Francisco
Published: August 2012

In this paper, we proposed a mechanistic breast cancer survival model based on the axillary lymph node chain structure, considering lymph nodes as a potential dissemination arrangement. We assume a naive breast cancer treatment protocol consisting of exposing patients first to a chemotherapy treatment on r intervals at k‐cycles separated by equal time intervals, and then they proceed to surgery. Our model, different from former ones, accommodates a quantity of contaminated lymph nodes, which is observed during surgery. We assume a generalised negative binomial survival distribution for the unknown number of contaminated lymph nodes after surgery, which, during an unknown period, may potentially propagate the disease. Estimation is based on a maximum likelihood approach. A simulation study assesses the coverage probability of asymptotic confidence intervals when small or moderate samples are considered. A Brazilian breast cancer data illustrate the applicability of our modelling. Copyright © 2012 John Wiley & Sons, Ltd.
Design of a 5‐kW advanced fuel cell polygeneration system
Authors: Samavati Mahrokh , Raza Rizwan , Zhu Bin
Published: August 2012

In this article, a planar, low‐temperature, solid‐oxide fuel cell based on nanocomposite materials is developed by cost‐effective tape casting and hot‐pressing methods. First, a single cell with active area of 6 × 6 cm2 was manufactured and tested to determine the cell performance. The power density of 0.4 and 0.7 W cm−2 were achieved at stable open‐circuit voltages at operating temperature of 550°C using the syngas and hydrogen, respectively. Based on these experimental results, a 5‐kW low‐temperature, solid‐oxide fuel cell polygeneration system is designed and analyzed. This system can provide electrical power and heating concurrently from a single source of fuel. The system design and the energy and mass balance are presented and a simulation based on syngas is performed. Finally, effects of fuel utilization factor, fuel cell operating temperature, and air temperature at cathode inlet on performance of polygeneration system is investigated.

This article is categorized under:

Fuel Cells and Hydrogen > Science and Materials

Energy Efficiency > Science and Materials
Anatomy of maximal stop mixing in the MSSM
Authors: Brümmer Felix , Kraml Sabine , Kulkarni Suchita
Published: August 2012

Abstract

A Standard Model-like Higgs near 125 GeV in the MSSM requires multi-TeV stop masses, or a near-maximal contribution to its mass from stop mixing. We investigate the maximal mixing scenario, and in particular its prospects for being realized it in potentially realistic GUT models. We work out constraints on the possible GUT-scale soft terms, which we compare with what can be obtained from some well-known mechanisms of SUSY breaking mediation. Finally, we analyze two promising scenarios in detail, namely gaugino mediation and gravity mediation with non-universal Higgs masses.
Future prospects for the determination of the Wilson coefficient $ C_{{^{{7\gamma }}}}^{\prime } $
Authors: Bečirević D. , Kou E. , Le Yaouanc A. , Tayduganov A.
Published: August 2012

Abstract

We discuss the possibilities of assessing a non-zero
$ C_{{^{{7\gamma }}}}^{\prime } $
from the direct and the indirect measurements of the photon polarization in the exclusive b → sγ(*) decays. We focus on three methods and explore the following three decay modes: B → K

*
(→ K

S

π
0)γ, B → K
1(→ Kππ)γ, and B → K

*
(→ Kπ)ℓ
+
ℓ
−. By studying different New Physics scenarios we show that the future measurement of conveniently defined observables in these decays could provide us with the full determination of C
7γ
and
$ C_{{^{{7\gamma }}}}^{\prime } $
.
Supersymmetric constraints from B

s
→ μ
+
μ
− and B → K

*

μ
+
μ
− observables
Authors: Mahmoudi F. , Neshatpour S. , Orloff J.
Published: August 2012

Abstract

We study the implications of the recent LHCb limit and results on B

s
→ μ
+
μ
− and B → K

*

μ
+
μ
− observables in the constrained SUSY scenarios. After discussing the Standard Model predictions and carefully estimating the theoretical errors, we show the constraining power of these observables in CMSSM and NUHM. The latest limit on BR(B

s
→ μ
+
μ
−), being very close to the SM prediction, constrains strongly the large tan β regime and we show that the various angular observables from B → K

*

μ
+
μ
− decay can provide complementary information in particular for intermediate tan β values.
FocusDET, A New Toolbox for SISCOM Analysis. Evaluation of the Registration Accuracy Using Monte Carlo Simulation
Authors: Martí Fuster Berta , Esteban Oscar , Planes Xavier , Aguiar Pablo , Crespo Cristina , Falcon Carles , Wollny Gert , Rubí Sureda Sebastià , Setoain Xavier , Frangi Alejandro F. , Ledesma Maria J. , Santos Andrés , Pavía Javier , Ros Domènec
Published: August 2012

Subtraction of Ictal SPECT Co-registered to MRI (SISCOM) is an imaging technique used to localize the epileptogenic focus in patients with intractable partial epilepsy. The aim of this study was to determine the accuracy of registration algorithms involved in SISCOM analysis using FocusDET, a new user-friendly application. To this end, Monte Carlo simulation was employed to generate realistic SPECT studies. Simulated sinograms were reconstructed by using the Filtered BackProjection (FBP) algorithm and an Ordered Subsets Expectation Maximization (OSEM) reconstruction method that included compensation for all degradations. Registration errors in SPECT-SPECT and SPECT-MRI registration were evaluated by comparing the theoretical and actual transforms. Patient studies with well-localized epilepsy were also included in the registration assessment. Global registration errors including SPECT-SPECT and SPECT-MRI registration errors were less than 1.2 mm on average, exceeding the voxel size (3.32 mm) of SPECT studies in no case. Although images reconstructed using OSEM led to lower registration errors than images reconstructed with FBP, differences after using OSEM or FBP in reconstruction were less than 0.2 mm on average. This indicates that correction for degradations does not play a major role in the SISCOM process, thereby facilitating the application of the methodology in centers where OSEM is not implemented with correction of all degradations. These findings together with those obtained by clinicians from patients via MRI, interictal and ictal SPECT and video-EEG, show that FocusDET is a robust application for performing SISCOM analysis in clinical practice.
Post‐vaccination anti‐human papillomavirus antibody seroprevalence among Czech teenaged girls and women
Authors: Petráš Marek , Sýkora Tomáš , Andrýs Ctirad , Drahošová Marcela
Published: August 2012

Objective

To evaluate seroprevalence among Czech girls and women previously vaccinated against human papillomavirus (HPV).

Methods

A commercial enzyme‐linked immunosorbent assay was used to determine the level of antibodies and seropositivity, with no genotype specification.

Results

A group of 356 teenaged girls and women with a mean age of 19.5 years (95% confidence interval [CI], 18.9–20.1 years) was found to have 94.1% HPV seropositivity (95% CI, 91.1%–96.3%) up to 3.5 years after vaccination. The vaccine‐specific total seropositivity rates were 98.0% and 85.0% among quadrivalent vaccinees (Gardasil; Merck, Whitehouse Station, NJ, USA) and bivalent vaccinees (Cervarix; GlaxoSmithKline, Brentford, UK), respectively. Adjusting for age and post‐vaccination time period, an expected 2:1 (quadrivalent:bivalent) ratio of the geometric mean concentrations of total HPV‐specific antibodies induced by the vaccines was observed. The antibody avidity remained almost unchanged up to 3.5 years later. Nevertheless, the mean avidity index was significantly higher among quadrivalent vaccinees (2.50 M GuHCl/mL; 95% CI, 2.42–2.58 M GuHCl/mL) than bivalent vaccinees (2.09 M GuHCl/mL; 95% CI, 2.01–2.17 M GuHCl/mL).

Conclusion

High anti‐HPV seroprevalence at a level related to the valency of vaccine used was achieved among Czech teenaged girls and women up to 3.5 years after vaccination.
Atrioventricular reentrant tachycardia with a 2:1 right bundle branch block
Authors: Kim Jun , Su Kim Jeong , Hyun Park Yong , Nam Gi‐Byoung
Published: August 2012

The phenomenon of a 2:1 bundle branch block is reported during atrioventricular (AV) nodal reentrant tachycardia, sinus tachycardia, atrial fibrillation, and atrial flutter. A 2:1 bundle branch block is attributed to first‐ and second‐degree bundle branch block, linking, electrical alternans, aberrancy, or supernormal conduction. However, the same phenomenon has not been reported in AV reentrant tachycardia. Herein, we report the case of a 52‐year‐old man presenting with orthodromic atrioventricular reentrant tachycardia with a 2:1 right bundle branch block.
Clinical characteristics, pathogens implicated and therapeutic outcomes of mixed infection in adult bacterial meningitis
Authors: Tsai Wan‐Chen , Chen Shu‐Fang , Chang Wen‐Neng , Lu Cheng‐Hsien , Chuang Yao‐Chung , Tsai Nai‐Wen , Chang Chiung‐Chih , Chien Chun‐Chih , Huang Chi‐Ren
Published: August 2012

We reviewed retrospectively the data for adult patients with bacterial meningitis over a period of 10.5 years in our hospital. The clinical characteristics and laboratory data of the 21 cases (52 strains) of mixed infection were analyzed. Two hundred and fifteen cases of single pathogen adult bacterial meningitis (ABM) were also included for comparison. Post‐neurosurgical type of ABM was presented in 86% of the mixed infection group. Brain abscess was found in three patients. Fourteen patients survived and seven cases died. The analysis showed a statistical significance for the mixed infection group having a higher rate of nosocomially‐acquired, post‐neurosurgical condition, hydrocephalus, and lower level of cerebrospinal fluid white cell count, protein and lactate than the single pathogen group. Logistic regression analysis showed the independent factor of “hydrocephalus” (p = 0.002). Presence of hydrocephalus is a significant neuroimaging feature when compared with the single pathogen group. As compared with the previous study results of mixed infection in ABM, the present study showed a change of pathogens implicated of increasingPseudomonasspp. andAcinetobacterspp. infections, and an emergence of anaerobic pathogens. All these changes deserve special attention because of the need for an appropriate choice of empirical antibiotics and choice of culture method.
Conclusion: Nowhere nation or better life? Ukraine’s past and future
Authors: D’Anieri Paul
Published: August 2012

All the authors in this collection of essays on Ukrainian politics stress the lack of improvement in the political situation in recent years. The authors identify a range of reasons including pre-Soviet history, the Soviet legacy, national identity, and political gridlock. While the authors disagree slightly on the extent to which change is impossible or merely difficulty, none is hopeful. The challenge for scholars is to avoid moving from objective analysis to assigning political blame. Some authors identify specific political actors on whom they fix blame, while others focus on less personal structural factors. The relative weight of structure-based and agent-based explanations is important in assessing the prospects for change in the future, and the possible paths to it.
Self-perception but not peer reputation of bullying victimization is associated with non-clinical psychotic experiences in adolescents
Authors: Gromann P. M. , Goossens F. A. , Olthof T. , Pronk J. , Krabbendam L.
Published: August 2012

Background

Bullying victimization may be linked to psychosis but only self-report measures of victimization have been used so far. This study aimed (a) to investigate the differential associations of peer-nominated versus self-reported victim status with non-clinical psychotic experiences in a sample of young adolescents, and (b) to examine whether different types of self-reported victimization predict non-clinical psychotic experiences in these adolescents.

Method

A combination of standard self-report and peer nomination procedures was used to assess victimization. The sample (n = 724) was divided into four groups (exclusively self-reported victims, self- and peer-reported victims, exclusively peer-reported victims, and non-victims) to test for a group effect on non-clinical psychotic experiences. The relationship between types of victimization and non-clinical psychotic experiences was examined by a regression analysis.

Results

Self-reported victims, along with self- and peer-reported victims, scored higher than peer-reported victims and non-victims on non-clinical psychotic experiences. Self-reports of direct relational, indirect relational and physical victimization significantly improved the prediction of non-clinical psychotic experiences whereas verbal and possession-directed victimization had no significant predictive value.

Conclusions

The relationship between victimization and non-clinical psychotic experiences is only present for self-reported victimization, possibly indicative of an interpretation bias. The observed discrepancy between self-report and peer-report highlights the importance of implementing a combination of both measures for future research.
Monosodium glutamate is not associated with overweight in Vietnamese adults
Authors: Thu Hien Vu Thi , Thi Lam Nguyen , Cong Khan Nguyen , Wakita Andrea , Yamamoto Shigeru
Published: August 2012

Objective

To determine the prevalence of and associated factors for overweight, especially to determine the relationship between the intake of monosodium glutamate (MSG) as a seasoning and overweight in Vietnam.

Design

A cross-sectional survey was conducted of Vietnamese adults aged ≥20 years in 2008. Dietary intake was assessed by the 24 h recall method for 3 d. MSG intake was evaluated by the weighing method on three consecutive days. Physical activity was assessed based on the Global Physical Activity Questionnaire recommended by the WHO. Overweight was defined as BMI ≥ 23·0 kg/m2. Other characteristics such as age and lifelong occupation were determined by a structured questionnaire.

Setting

Some rural and urban areas of Hanoi, Thua Thien Hue Province and Ho Chi Minh City, Vietnam.

Subjects

A total of 1528 adults living in surveyed areas were randomly selected by the multistage cluster sampling method.

Results

The prevalence of overweight was 27·9 %, and 81·0 % of participants were MSG users. Average MSG intake was 2·2 (sd 1·8) g/d. Multiple logistic regression analysis revealed that factors associated with overweight were age, region of residence, lifelong occupation, physical activity and intakes of energy, carbohydrates, saturated fat and animal protein. There was no significant association between MSG intake and overweight.

Conclusions

The study demonstrated that overweight was not associated with MSG intake in Vietnamese adults. Further longitudinal studies should be done in different populations to determine the relationship between MSG and overweight.
Choosing between subsidized or unsubsidized private pension schemes: evidence from German panel data
Authors: PFARR CHRISTIAN , SCHNEIDER UDO
Published: August 2012

Since 2002, the German government has been attempting to increase private old-age provisions by introducing incentives such as supplementary subsidies and tax credits. Since then, the so-called ‘Riester pension’ has grown in popularity. Apart from subsidized pension plans, unsubsidized private pension insurances have – already in the past – been a very important instrument among old-age provision schemes. With data of the German SAVE study for the years 2005–2009, we analyze whether the decision for a ‘Riester pension’ is independent of the decision for unsubsidized private pension insurance using methods for simultaneous equations. Our estimates indicate that decisions on ‘Riester’ and private pensions are not independent and the proposed random parameters bivariate probit model results in efficiency gains compared to separate probit estimations. Regarding governmental subsidies, we find positive incentive effects of child subsidies, whereas low income earners are not seen to increase their old-age provisions. Further, there is strong evidence for a ‘crowding-in’ among alternative assets, i.e., that individuals holding various assets make additional investments in ‘Riester pensions’ or private pension insurances. Finally, when subsidies are given, these subsidies are a clearly stronger saving motive than the aim to make provisions for old age, a result confirmed by the additional fixed-effects estimations.