bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on crystallization behavior and hydrophilicity of poly(vinylidene fluoride)/poly(methyl methacrylate)/poly(vinyl pyrrolidone) ternary blends by solution casting
Authors: Cheng Jing , Zhang Jun , Wang Xiaolin
Published: May 2012

Ternary blends composed of matrix polymer poly(vinylidene fluoride) (PVDF) with different proportions of poly(methyl methacrylate) (PMMA)/poly(vinyl pyrrolidone) (PVP) blends were prepared by solution casting. The crystallization behavior and hydrophilicity of ternary blends were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), wide angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and contact angle test. According to morphological analysis, the surface was full of typical spherulitic structure of PVDF and the average diameter was in the order of 3 μm. The samples presented predominantly β phase of PVDF by solution casting. It indicated that the size of surface spherulites and crystalline phase had little change with the PMMA or PVP addition. Moreover, FTIR demonstrated special interactions among the ternary polymers, which led to the shift of the carbonyl stretching absorption band of PVP. On the other hand, the melting, crystallization temperature, and crystallinity of the blends had a little change compared with the neat PVDF in the first heating process. Except for the content of PVP containing 30 wt %, the crystallinity of PVDF decreased remarkably from 64% to 33% and the value of t1/2 was not obtained. Besides, the hydrophilicity of PVDF was remarkably improved by blending with PMMA/PVP, especially when the content of PVP reached 30 wt %, the water contact angle displayed the lowest value which decreased from 98.8° to 51.0°. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Poly(glycerol–sebacate) bioelastomers—kinetics of step‐growth reactions using Fourier Transform (FT)‐Raman spectroscopy
Authors: Maliger Raju , Halley Peter J. , Cooper‐White Justin J.
Published: May 2012

Kinetic studies of the esterification of glycerol (G) and sebacic acid (SA) at three molar ratios (0.6, 0.8, 1.0) and at three temperatures (120, 130, 140°C) to form poly(glycerol–sebacate) were performed and assessed using FT‐Raman spectroscopy. The quantitative changes in the concentrations of carboxylic acid and ester groups within the forming bioelastomer were measured and the chemical rate constants (k) determined from the kinetic scheme were first‐order, with respect to sebacic acid concentration. Increasing the reaction temperature by 20°C is noted to increase the chemical rate constant (k) by a factor of up to 4.5 and the total extent of conversion at early times for the molar ratios investigated. The activation energy (Ea) and the pre‐exponential factor (A0) for these three stoichiometric ratios were calculated, which varied in accordance with the average functionality of the system. Under isothermal conditions, the chemical rate constant remained unchanged with an increase in the extent of the reaction (α) until a spontaneous transition resulted in the shift in the mechanism from kinetics to diffusion controlled. The Young's moduli of the PGS polymers were found to depend primarily on the average functionality of the system and the curing period. This investigation confirms the reaction mechanism for PGS polymer synthesis and shows the flexibility afforded to PGS properties and reaction times through varying the stoichiometric ratios of glycerol to sebacic acid. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Design of lubricating grease formulations using recycled polypropylene from postconsumer films as thickener agent
Authors: Martín‐Alfonso J. E. , Valencia C. , Arteaga J. F. , Díaz M. J. , Franco J. M.
Published: May 2012

This work deals with the design of lubricating greases formulations based on blends of mineral oil and recycled polypropylene from postconsumer waste, coming from films with inks. In particular, the influence of polymer concentration on the rheological, mechanical, and thermal properties of recycled polymer/oil blends was characterized. From the experimental results obtained, it can be deduced that the evolution of recycled polymer/mineral oil formulations on linear viscoelasticity functions with frequency is quite similar to that found for traditional lithium greases. It is observed that these blends form systems with enhanced “plateau” modulus, G, with respect to industrial standard lubricating greases, which could be represent an important advantage, from an economic and environmental point of view. However, the influence of temperature on linear viscoelasticity functions is more pronounced than that found for traditional greases. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Stimuli‐responsive recognition of BSA‐imprinted poly vinyl acetate grafted calcium alginate core‐shell hydrogel microspheres
Authors: Ying Xiaoguang , Qi Liangliang , Li Xiao , Zhang Weiying , Cheng Guoxiang
Published: May 2012

Poly vinyl acetate grafted calcium alginate hydrogel microspheres were prepared with bovine serum albumin (BSA) as molecular template. The microspheres exhibited homogeneous and core‐shell structure according to different preparation strategy. The rebinding and swelling property of microspheres showed responsiveness toward ionic strength, temperature, and pH. It was found the highest separation factor of 1.85 and imprinting efficiency of 1.75 when the Ca2+ ionic strength was 1.25 and 0.34 mol/kg, respectively. The separation factor was found decreased as temperature grew from 29 to 45°C while the imprinting efficiency reached a peak value at about 37°C. Separation factor of BSA imprinted microspheres at different pH was also recorded and two peaks were found, which were considered to be caused by the similar swollen state due to ionic and covalent crosslinking structure of modified microspheres. The recognition responsiveness is suggested to be influenced by environmental effects due to the changing in imprints' configuration at different swollen states. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Influence of the structure of the onium iodide salts on the properties of modified montmorillonite
Authors: Livi Sébastien , Dufour Christian , Gaumont Annie‐Claude , Levillain Jocelyne , Pham Thi‐Nhàn
Published: May 2012

Dialkyl imidazoline, alkyl pyridine and alkyl quinoline containing salts have been synthesized and used as new surfactants for cationic exchange of layered silicates, such as montmorillonite (MMT) in order to evaluate their role in the formation of intercalated MMT clays. The new salts have been characterized by FTIR, 1H, 13C‐NMR spectra. These compounds have been intercalated into the layers of MMT via a solution dispersion technique and the extent of the interlayer space expansion was confirmed by using wide angle X‐ray diffraction and FTIR spectra. Thermogravimetry analysis shows that these salts can be used in place of ammonium salts to produce organophilic clays with higher thermal stability than commercial alkyl ammonium‐treated MMT. Moreover, the results also show that the imidazolium‐modified clays have a greater thermal stability compared to the quinolinium and the pyridinium‐modified clay. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Equal‐channel multiple angular extrusion of polyethylene
Authors: Beloshenko Victor A. , Voznyak Andrei V. , V. Voznyak Yuri , Dudarenko Galina V.
Published: May 2012

The effect of accumulated deformation and deformation routes in the course of equal‐channel multiple angular extrusion (ECMAE) on physical and mechanical properties of polyethylene (PE) differed in molecular mass (MM) has been studied. As deformation routes, route C (shear planes are parallel, and the simple shear direction of every deformation zone is changed through 180°) and route E (shear planes are turned through ±45° around the extrusion axis and the normal to the axis, and simple shear direction is changed through 180° or ±90° with respect to the deformation zone) were selected. It has been shown that ECMAE provides the increase of microhardness H, modulus of elasticity E, and tensile strength σT up to 4.5 times with strain at break εb staying practically at the level of εb of the initial material. The value of the effects achieved depends on MM, accumulated deformation and the selected deformation route. The best set of physical and mechanical characteristics was observed in the case of route E. The observed effects are related to the formation of a special orientation order and increased degree of crystallinity of extrudates. According to SEM data, route C results in mostly uniaxial orientation of macrofibrils at an angle of 35° to the direction of extrusion, and formation of a part of tie fibrils and macrofibrils oriented perpendicularly to the main orientation. The route E produces biaxial orientation of macrofibrils. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Differential inhibitory effects of proton pump inhibitors on the metabolism and antiplatelet activities of clopidogrel and prasugrel
Authors: Chen Chia‐Hao , Yang Jyh‐Chin , Uang Yow‐Shieng , Lin Chun‐Jung
Published: May 2012

The interaction between proton pump inhibitors (PPIs) and clopidogrel/prasugrel was investigated. The IC50 values of omeprazole, esomeprazole, lansoprazole, pantoprazole and rabeprazole on the metabolic ratios of 2‐oxo‐clopidogrel/clopidogrel, H4 (the active metabolite of clopidogrel)/2‐oxo‐clopidogrel and R‐138727 (the active metabolite of prasugrel)/prasugrel thiolactone in human liver microsomes were determined. The antiplatelet activities of clopidogrel and prasugrel were measured with or without PPIs. As a result, most PPIs (except for pantoprazole) inhibited the formation of 2‐oxo‐clopidogrel with IC50 values of 20–32 μm and inhibited the formation of H4 with IC50 values of 6–20 μm. PPIs inhibited the formation of R‐138727 with IC50 values of 9–25 μm. Among the tested PPIs, omeprazole exhibited the highest inhibitory potency on the formation of H4. Omeprazole, esomeprazole and rabeprazole exhibited the highest inhibitory potencies on the formation of R‐138727. For platelet aggregation, omeprazole and lansoprazole show higher inhibitory effects on the antiplatelet activity of clopidogrel. On the other hand, omeprazole, esomeprazole and rabeprazole significantly decreased the antiplatelet activity of prasugrel thiolactone. These data indicate that PPIs differ in their effects of inhibiting the metabolism and antiplatelet activities of clopidogrel and prasugrel. Copyright © 2012 John Wiley & Sons, Ltd.
About the structural role of disulfide bridges in serum albumins: Evidence from protein simulated unfolding
Authors: Paris Guillaume , Kraszewski Sebastian , Ramseyer Christophe , Enescu Mironel
Published: May 2012

The role of the 17 disulfide (SS) bridges in preserving the native conformation of human serum albumin (HSA) is investigated by performing classical molecular dynamics (MD) simulations on protein structures with intact and, respectively, reduced SS bridges. The thermal unfolding simulations predict a clear destabilization of the protein secondary structure upon reduction of the SS bridges as well as a significant distortion of the tertiary structure that is revealed by the changes in the protein native contacts fraction. The effect of the SS bridges reduction on the protein compactness was tested by calculating Gibbs free energy profiles with respect to the protein gyration radius. The theoretical results obtained using the OPLS‐AA and the AMBER ff03 force fields are in agreement with the available experimental data. Beyond the validation of the simulation method, the results here reported provide new insights into the mechanism of the protein reductive/oxidative unfolding/folding processes. It is predicted that in the native conformation of the protein, the thiol (SH) groups belonging to the same reduced SS bridge are located in potential wells that maintain them in contact. The SH pairs can be dispatched by specific conformational transitions of the peptide chain located in the neighborhood of the cysteine residues. © 2012 Wiley Periodicals, Inc. Biopolymers 97:889–898, 2012.
High‐titer n‐butanol production by clostridium acetobutylicum JB200 in fed‐batch fermentation with intermittent gas stripping
Authors: Xue Chuang , Zhao Jingbo , Lu Congcong , Yang Shang‐Tian , Bai Fengwu , Tang I.‐Ching
Published: May 2012

Acetone–butanol–ethanol (ABE) fermentation with a hyper‐butanol producing Clostridium acetobutylicum JB200 was studied for its potential to produce a high titer of butanol that can be readily recovered with gas stripping. In batch fermentation without gas stripping, a final butanol concentration of 19.1 g/L was produced from 86.4 g/L glucose consumed in 78 h, and butanol productivity and yield were 0.24 g/L h and 0.21 g/g, respectively. In contrast, when gas stripping was applied intermittently in fed‐batch fermentation, 172 g/L ABE (113.3 g/L butanol, 49.2 g/L acetone, 9.7 g/L ethanol) were produced from 474.9 g/L glucose in six feeding cycles over 326 h. The overall productivity and yield were 0.53 g/L h and 0.36 g/g for ABE and 0.35 g/L h and 0.24 g/g for butanol, respectively. The higher productivity was attributed to the reduced butanol concentration in the fermentation broth by gas stripping that alleviated butanol inhibition, whereas the increased butanol yield could be attributed to the reduced acids accumulation as most acids produced in acidogenesis were reassimilated by cells for ABE production. The intermittent gas stripping produced a highly concentrated condensate containing 195.9 g/L ABE or 150.5 g/L butanol that far exceeded butanol solubility in water. After liquid–liquid demixing or phase separation, a final product containing ∼610 g/L butanol, ∼40 g/L acetone, ∼10 g/L ethanol, and no acids was obtained. Compared to conventional ABE fermentation, the fed‐batch fermentation with intermittent gas stripping has the potential to reduce at least 90% of energy consumption and water usage in n‐butanol production from glucose. Biotechnol. Bioeng. 2012; 109: 2746–2756. © 2012 Wiley Periodicals, Inc.
Systematic review and meta-analysis of outcomes after intraoperative pancreatic duct stent placement during pancreaticoduodenectomy
Authors: Xiong J J , Altaf K , Mukherjee R , Huang W , Hu W M , Li A , Ke N W , Liu X B
Published: May 2012

Background

Postoperative pancreatic leakage after pancreaticoduodenectomy is often serious. Although some studies have suggested that stenting the anastomosis can reduce the incidence of this complication, the value of stenting in the setting of pancreaticoduodenectomy remains unclear.

Methods

Studies comparing outcomes of stent versus no stent, and internal versus external stent placement for pancreaticoduodenectomy were eligible for inclusion. Pooled odds ratios (ORs) with 95 per cent confidence intervals were calculated using fixed- or random-effects models.

Results

From a search of the literature published between January 1973 and September 2011, five randomized clinical trials (RCTs) and 11 non-randomized observational clinical studies (OCS) involving 1726 patients were selected for inclusion in this review. Meta-analysis of RCTs revealed that placing a stent in the pancreatic duct did not reduce the incidence of postoperative pancreatic fistula. External stents had no advantage over internal stents in terms of clinical outcome. Subgroup analyses revealed that use of an external stent significantly reduced the incidence of pancreatic fistula (RCTs: OR 0·42, 0·24 to 0·76, P = 0·004; OCS: OR 0·43, 0·27 to 0·68, P < 0·001), delayed gastric emptying (RCTs: OR 0·41, 0·19 to 0·87, P = 0·02) and postoperative morbidity (RCTs: OR 0·55, 0·34 to 0·89, P = 0·02) compared with no stent.

Conclusion

Pancreatic duct stenting did not reduce the incidence of pancreatic fistula and other complications in pancreaticoduodenectomy compared with no stenting. Although no difference was found between external and internal stents in terms of efficacy, external stents seemed to reduce the incidence of pancreatic fistula compared with control.
Real-time monitoring of liver damage during experimental ischaemia–reperfusion using a nitric oxide sensor
Authors: Nakagawa A , Yokoyama Y , Suzuki H , Shoji K , Watanabe Y , Imamura A , Kokuryo T , Nagino M
Published: May 2012

Background

Hepatic ischaemia–reperfusion (IR) injury may lead to liver damage during liver surgery, and intrahepatic nitric oxide (NO) levels may play a role in this context. The aim of this study was to demonstrate real-time changes in intrahepatic NO concentration during IR and to correlate potential hepatic NO production with liver damage using a selective NO sensor.

Methods

Wistar rats were exposed to 15 min of hepatic ischaemia followed by reperfusion, after which changes in intrahepatic NO levels were measured using an NO sensor. Additionally, rats were exposed to five successive periods of IR, each consisting of 15 min ischaemia followed by 5 or 15 min reperfusion, and hepatic damage was evaluated by blood tests and histological examination. Hepatic expression of Akt, phosphorylated Akt, endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS was examined at different time points during and after IR by western blot and immunohistochemical analysis.

Results

During ischaemia, intrahepatic NO levels increased and reached a plateau at approximately 10 min. Repeated 15 min ischaemia–5 min reperfusion cycles reduced the maximum amount of NO produced during ischaemia gradually, and almost no NO production was observed during the fifth period of ischaemia. NO production following repeated ischaemia was proportional to the degree of hepatic viability. Phosphorylated eNOS was upregulated and correlated with the level of NO production during hepatic ischaemia.

Conclusion

Intrahepatic NO levels decrease during repeated IR in rats. Real-time monitoring of intrahepatic NO levels is useful for the prediction of IR-related liver injury during experimental liver surgery.
Development and validation of a liquid chromatography–tandem mass spectrometry method for the determination of febuxostat in human plasma
Authors: Wang Haidong , Deng Pan , Chen Xiaoyan , Guo Lixia , Zhong Dafang
Published: May 2012

A rapid and sensitive analytical method based on liquid chromatography coupled to tandem mass spectrometry detection with positive ion electrospray ionization was developed for the determination of febuxostat in human plasma using d7‐febuxostat as the internal standard (IS). A simple protein precipitation was performed using acetonitrile. The analyte and IS were subjected to chromatographic analysis on a Capcell PAK C18 column (4.6 × 100 mm, 5 µm) using acetonitrile–5 mm ammonium acetate–formic acid (85:15:0.015, v/v/v) as the mobile phase at a flow rate of 0.6 mL/min. An Agilent 6460 electrospray tandem mass spectrometer was operated in the multiple reaction monitoring mode. The precursor‐to‐product ion transitions m/z 317 → m/z 261 (febuxsotat) and m/z 324 → m/z (261 + 262) (d7‐febuxostat, IS) were used for quantitation. The results were linear over the studied range (10.0–5000 ng/mL), and the total analysis time for each chromatograph was 3 min. The intra‐ and inter‐day precisions were less than 7.9 and 7.2%, respectively, and the accuracy was within ±4.2%. No evidence of analyte instability in human plasma was observed storage at −20°C for 31 days. This method was successfully applied in the determination of febuxostat concentrations in plasma samples from healthy Chinese volunteers. Copyright © 2012 John Wiley & Sons, Ltd.
Validation and application of a liquid chromatography‐tandem mass spectrometric method for the determination of GDC‐0152 in human plasma using solid‐phase extraction
Authors: Shin Young G. , Jones Steve A. , Murakami Stan C. , Budha Nageshwar , Ware Joseph , Wong Harvey , Buonarati Michael H. , Dean Brian , Hop Cornelis E. C. A.
Published: May 2012

A liquid chromatography–tandem mass spectrometric (LC‐MS/MS) method was developed and validated for the determination of GDC‐0152 in human plasma to support clinical development. The method consisted of a solid‐phase extraction for sample preparation and LC‐MS/MS analysis in the positive ion mode using TurboIonSprayTM for analysis. d7‐GDC‐0152 was used as the internal standard. A linear regression (weighted 1/concentration2) was used to fit calibration curves over the concentration range of 0.02–10.0 ng/mL for GDC‐0152. There were no endogenous interference components in the blank human plasma tested. The accuracy at the lower limit of quantitation was 99.3% with a precision (%CV) of 13.9%. For quality control samples at 0.0600, 2.00 and 8.00 ng/mL, the between‐run %CV was ≤8.64. Between‐run percentage accuracy ranged from 98.2 to 99.6%. GDC‐0152 was stable in human plasma for 363 days at −20°C and for 659 days at −70°C storage. GDC‐0152 was stable in human plasma at room temperature for up to 25 h and through three freeze–thaw cycles. In whole blood, GDC‐0152 was stable for 12 h at 4°C and at ambient temperature. This validated LC‐MS/MS method for determination of GDC‐0152 was used to support clinical studies. Copyright © 2012 John Wiley & Sons, Ltd.
Development and validation of LC‐MS/MS method for the estimation of β‐hydroxy‐β‐methylbutyrate in rat plasma and its application to pharmacokinetic studies
Authors: Deshpande Parag , Jie Zhang , Subbarayan Ramesh , Mamidi Vijay Kumar , Chunduri Raja Haranadha Babu , Das Tapas , Shreeram Sathyavageeswaran
Published: May 2012

A simple, sensitive and specific high‐performance liquid chromatography mass spectrometry (LC‐MS/MS) method was developed and validated for the quantification of β‐hydroxy‐β‐methyl butyrate (HMB) in small volumes of rat plasma using warfarin as an internal standard (IS). The API‐4000 LC‐MS/MS was operated under the multiple reaction‐monitoring mode using the electrospray ionization technique. A simple liquid–liquid extraction process was used to extract HMB and IS from rat plasma. The total run time was 3 min and the elution of HMB and IS occurred at 1.48 and 1.75 min respectively; this was achieved with a mobile phase consisting of 0.1% formic acid in a water–acetonitrile mixture (15:85, v/v) at a flow rate of 1.0 mL/min on a Agilent Eclipse XDB C8 (150 × 4.6, 5 µm) column. The developed method was validated in rat plasma with a lower limit of quantitation of 30.0 ng/mL for HMB. A linear response function was established for the range of concentrations 30–4600 ng/mL (r > 0.998) for HMB. The intra‐ and inter‐day precision values for HMB were acceptable as per Food and Drug Administration guidelines. HMB was stable in the battery of stability studies, viz. bench‐top, autosampler freeze–thaw cycles and long‐term stability for 30 days in plasma. The developed assay method was applied to a bioavailability study in rats. Copyright © 2012 John Wiley & Sons, Ltd.
A universal surrogate peptide to enable LC‐MS/MS bioanalysis of a diversity of human monoclonal antibody and human Fc‐fusion protein drug candidates in pre‐clinical animal studies
Authors: Furlong Michael T. , Ouyang Zheng , Wu Steven , Tamura James , Olah Timothy , Tymiak Adrienne , Jemal Mohammed
Published: May 2012

For the development of human antibody Fc (fraction crystallizable) region‐containing therapeutic protein candidates, which can be either monoclonal antibodies (mAbs) or pharmacologically active proteins/peptides fused to the Fc region of human Immunoglobulin G (IgG), reliable quantification of these proteins in animal pharmacokinetic study plasma samples is critical. LC‐MS/MS has emerged as a promising assay platform for this purpose. LC‐MS/MS assays used for bioanalysis of human antibody Fc region‐containing therapeutic protein candidates frequently rely upon quantification of a ‘signature’ surrogate peptide whose sequence is unique to the protein analyte of interest. One drawback of the signature peptide approach is that a new LC‐MS/MS assay must be developed for each new human Fc region‐containing therapeutic protein. To address this issue, we propose an alternative ‘universal surrogate peptide’ approach for the quantification of human antibody Fc region‐containing therapeutic protein candidates in plasma samples from all nonclinical species. A single surrogate tryptic peptide was identified in the Fc region of most human antibody Fc‐containing therapeutic protein candidates. An LC‐MS‐MS method based upon this peptide was shown to be capable of supporting bioanalysis of a diversity of human Fc region‐containing therapeutic protein candidates in plasma samples of all commonly used animal species. Copyright © 2012 John Wiley & Sons, Ltd.
A unified structure for crowd simulation
Authors: Jund Thomas , Kraemer Pierre , Cazier David
Published: May 2012

Realistic simulation of crowds is an important issue for the production of virtual worlds for games, entertainment or architectural and urban planning. Difficult issues need to be addressed such as collision avoidance and the handling of dynamic environments. In this paper, we present a unified structure for the simulation of crowds in complex urban environments. We propose a topological multiresolution model supporting different levels of details, allowing efficient proximity querying and compatible with real‐time rendering and hierarchical path planning. A fine exploitation of the multiscale aspect of the underlying model allows to achieve the same efficiency as the fastest existing methods. The generality of the approach allows the simulation to be executed on any two manifold, and the unified approach eases the handling of dynamic environments. Copyright © 2012 John Wiley & Sons, Ltd.
Perceptually plausible formations for virtual conversers
Authors: Ennis Cathy , O'Sullivan Carol
Published: May 2012

Recent progress in real‐time simulations has led to a higher demand for believability from virtual characters. Background characters are becoming a more integral part of games, with emphasis being placed in particular on interactions between them. Conversing groups can play a significant role in adding plausibility, or a sense of presence, to a real‐time simulation. However, it is not obvious how best to generate and vary these kinds of groups. In this paper, using anthropological standards for interacting distances and formations, we conduct a series of experiments to examine how these parameters inherent in human conversation are perceived for virtual characters. Our results show that, although participants were sensitive to both distance and orientation changes between talkers and listeners in a virtual conversation, they were not as sensitive to anomalous gesturing behaviours across different distances. Copyright © 2012 John Wiley & Sons, Ltd.
Silver‐coated copper nanowires with improved anti‐oxidation property as conductive fillers in low‐density polyethylene
Authors: Luo Xiaoxiong , Gelves Genaro A. , Sundararaj Uttandaraman , Luo Jing‐Li
Published: May 2012

Silver‐coated copper nanowires (AgCuNWs) are prepared by chemical plating method with copper nanowires (CuNWs) and Ag‐amine reagent. The prepared AgCuNWs with silver content of 66.52 wt.%, diameter 28–33 nm exhibited improved anti‐oxidation behaviour. The silver coating on AgCuNWs can effectively reduce the formation of copper oxide under room temperature. The temperature at which nanowires begin to gain weight can be improved from 85 to 230°C and the maximum weight gain can be decreased from 20.3% to 3.2% by applying silver coating. The volume electrical resistivity of the AgCuNWs filled low‐density polyethylene nanocomposites is lower than that of the CuNWs filled low‐density polyethylene nanocomposites with same volume percentage of fillers because the silver content in the AgCuNWs is not oxidised during compression moulding. © 2012 Canadian Society for Chemical Engineering
The Role of octopamine and tyramine in Drosophila larval locomotion
Authors: Selcho Mareike , Pauls Dennis , el Jundi Basil , Stocker Reinhard F. , Thum Andreas S.
Published: May 2012

The characteristic crawling behavior of Drosophila larvae consists of a series of rhythmic waves of peristalsis and episodes of head swinging and turning. The two biogenic amines octopamine and tyramine have recently been shown to modulate various parameters of locomotion, such as muscle contraction, the time spent in pausing or forward locomotion, and the initiation and maintenance of rhythmic motor patterns. By using mutants having altered octopamine and tyramine levels and by genetic interference with both systems we confirm that signaling of these two amines is necessary for larval locomotion. We show that a small set of about 40 octopaminergic/tyraminergic neurons within the ventral nerve cord is sufficient to trigger proper larval locomotion. Using single‐cell clones, we describe the morphology of these neurons individually. Given various potential roles of octopamine and tyramine in the larval brain, such as locomotion, learning and memory, stress‐induced behaviors or the regulation of the energy state, functions that are often not easy to discriminate, we dissect here for the first time a subset of this complex circuit that modulates specifically larval locomotion. Thus, these data will help to understand—for a given neuronal modulator—how specific behavioral functions are executed within distinct subcircuits of a complex neuronal network. J. Comp. Neurol. 520:3764–3785, 2012. © 2012 Wiley Periodicals, Inc.
Electromagnetism‐like method tuned constant modulus algorithm for blind detector in multicarrier CDMA system
Authors: Hung Ho‐Lung
Published: May 2012

This paper presents an efficient meta‐heuristic algorithm based on electromagnetism‐like method, which has been successfully implemented in multiuser detection problems. The contribution revisits blind multiuser detection for multicarrier code division multiple access systems using a novel combined adaptive step‐size constant modulus algorithm (CMA) and electromagnetism‐like method scheme. To work around potentially computational intractability and improved the capability of suppressing multiple access interference (MAI) for Multicarrier CDMA System, the proposed scheme exploits heuristics in consideration of both global and local exploration of the step size of the CMA. Simulation results obtained confirm that faster convergence and desirable BER performance with low computational complexity can be achieved with electromagnetism‐like method based CMA scheme, compared with the previous step‐size CMA scheme, genetic algorithm, and particle swarm optimization with CMA scheme. Copyright © 2012 John Wiley & Sons, Ltd.
Urine cytomorphology of micropapillary urothelial carcinoma
Authors: Zhu Bing , Rohan Stephen M. , Lin Xiaoqi
Published: May 2012

Micropapillary urothelial carcinoma (MPUC) is a rare subtype of urothelial carcinoma (UC) with an aggressive clinical course. The cytomorphologic features of MPUC in urine cytology have not been well described. In this study, 23 urine specimens (11 voided urines and 12 bladder washings) from 23 patients with MPUC on follow‐up surgical material and 28 specimens (14voided urines and 14 bladder washings) from 28 patients with high‐grade UCs (HGUC) were retrieved. Cytologic features (nuclear grade, cytoplasmic characteristics), architectural features (single cell pattern, true papillary structures, flat sheets/nests, three dimensional clusters, micropapillary (inside‐out, acinar‐like, or cauliflower with nuclei located peripherally)), and necrosis were evaluated. Clinical follow‐up was obtained by chart review. Two findings, micropapillae and cytoplasmic vacuoles, were seen more frequently in MPUC compared to HGUC, 81.0% vs. 14.3%, and 57.1% vs. 14.3%, respectively. The combination of these two findings had a sensitivity of 78%, a specificity of 86%, a positive predictive value of 82%, and a negative predictive value of 83% for the diagnosis of MPUC on subsequent biopsy. MPUC and HGUC can both exhibit a single cell pattern, papillary structures, flat sheets/nests, three dimensional clusters, high‐nuclear grade, and necrosis, thus these findings are not useful in distinguishing these entities. Chart review revealed that patients with MPUC had a higher rate of metastasis to lymph nodes and distant organs than HGUC, 57% vs. 4%. Therefore, the findings of cytoplasmic vacuoles and micropapillary structures in UC from a urine cytology specimen are associated with MPUC on subsequent biopsy. Diagn. Cytopathol. 2013. © 2012 Wiley Periodicals, Inc.
Endoscopic ultrasound‐guided fine‐needle aspiration diagnosis of large cell neuroendocrine carcinoma of the gallbladder and common bile duct: Report of a case
Authors: Samad Arbaz , Kaplan Alesia , Arain Mustafa , Attam Rajeev , Jessurun Jose , Manivel J. Carlos , Pambuccian Stefan E.
Published: May 2012

Endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA) allows a reliable and accurate diagnosis of neoplasms of the gallbladder and bile ducts. We report the cytopathologic findings of a case of large cell neuroendocrine carcinoma (LCNEC) of the gallbladder and extrahepatic bile ducts in a 67‐year‐old woman who presented with progressive abdominal pain and jaundice. EUS‐FNA of the mass involving the common bile duct and of a porta hepatis lymph node showed abundant cellularity with tumor cells arranged singly and occasionally in tight and loose clusters and rosette‐like structures in a background showing extensive necrotic debris. The tumor cells were predominantly plasmacytoid, showed a moderate amount of focally vacuolated cytoplasm and large round to oval hyperchromatic nuclei with prominent nucleoli, numerous mitoses, and apoptotic bodies. The differential diagnosis included poorly differentiated adenocarcinoma, lymphoma, melanoma, and poorly differentiated neuroendocrine carcinoma (NEC), large cell type. The tumor cells were strongly and diffusely positive for cytokeratin AE1/AE3, CD56, synaptophysin, and chromogranin and showed a very high proliferative fraction on Ki67 staining, supporting the diagnosis of a high‐grade NEC. Due to the large size of the neoplastic cells, moderate amounts of cytoplasm and prominent nucleoli, a diagnosis of LCNEC was made on the EUS‐FNA sample. Despite the prompt institution of chemotherapy, the patient died shortly thereafter and the diagnosis was confirmed at autopsy. This is to our knowledge the first case of LCNEC of the gallbladder and bile ducts diagnosed by EUS‐FNA. Diagn. Cytopathol. 2013;41:1091–1095. © 2012 Wiley Periodicals, Inc.
Experimental evaluation of rectangular reinforced concrete column behaviour under biaxial cyclic loading
Authors: Rodrigues Hugo , Arêde António , Varum Humberto , Costa Aníbal G.
Published: May 2012

The cyclic behaviour of reinforced concrete columns has been the subject of many experimental studies in recent years. However, most of these studies have focused on the unidirectional loading of columns with square cross‐sections under constant axial loading conditions. In the present study, four types of full‐scale quadrangular building columns were tested under different types of loading, including uniaxial and biaxial loading conditions. The first two specimens of each column type were independently cyclically tested in the strong and weak directions. Bidirectional tests using different loading paths were performed on the other column specimens. All columns were tested under constant axial loading conditions. In this paper, the experimental results are presented, and the global behaviour of tested columns is discussed, particularly focusing on the stiffness and strength degradation because of the increasing cyclic demand. Finally, the deformation‐based performance limits proposed in Part 3 of Eurocode 8 were calculated and compared with the experimental results. Copyright © 2012 John Wiley & Sons, Ltd.
Damping identification of a full‐scale passively controlled five‐story steel building structure
Authors: Ji Xiaodong , Hikino Tsuyoshi , Kasai Kazuhiko , Nakashima Masayoshi
Published: May 2012

A series of large‐scale dynamic tests was conducted on a passively controlled five‐story steel building on the E‐Defense shaking table facility in Japan to accumulate knowledge of realistic seismic behavior of passively controlled structures. The specimen was tested by repeatedly inserting and replacing each of four damper types, that is, the buckling restrained braces, viscous dampers, oil dampers, and viscoelastic dampers. Finally, the bare steel moment frame was tested after removing all dampers. A variety of excitations was applied to the specimen, including white noise, various levels of seismic motion, and shaker excitation. System identification was implemented to extract dynamic properties of the specimen from the recorded floor acceleration data. Damping characteristics of the specimen were identified. In addition, simplified estimations of the supplemental damping ratios provided by added dampers were presented to provide insight into understanding the damping characteristics of the specimen. It is shown that damping ratios for the specimen equipped with velocity‐dependent dampers decreased obviously with the increasing order of modes, exhibiting frequency dependency. Damping ratios for the specimen equipped with oil and viscoelastic dampers remained constant regardless of vibration amplitudes, whereas those for the specimen equipped with viscous dampers increased obviously with an increase in vibration amplitudes because of the viscosity nonlinearity of the dampers. In very small‐amplitude vibrations, viscous and oil dampers provided much lower supplemental damping than the standard, whereas viscoelastic dampers could be very efficient. Copyright © 2012 John Wiley & Sons, Ltd.
A formally second‐order cell centred scheme for convection–diffusion equations on general grids
Authors: Piar L. , Babik F. , Herbin R. , Latché J.‐C.
Published: May 2012

We propose, in this paper, a finite volume scheme to compute the solution of the convection–diffusion equation on unstructured and possibly non‐conforming grids. The diffusive fluxes are approximated using the recently published SUSHI scheme in its cell centred version, that reaches a second‐order spatial convergence rate for the Laplace equation on any unstructured two‐dimensional/three‐dimensional grids. As in the MUSCL method, the numerical convective fluxes are built with a prediction‐limitation process, which ensures that the discrete maximum principle is satisfied for pure convection problems. The limitation does not involve any geometrical reconstruction, thus allowing the use of completely general grids, in any space dimension. Copyright © 2012 John Wiley & Sons, Ltd.
Spatial interpolation of sub‐daily air temperatures for snow and hydrologic applications in mesoscale Alpine catchments
Authors: Jabot E. , Zin I. , Lebel T. , Gautheron A. , Obled C.
Published: May 2012

Air temperature represents a key parameter for snow hydrology, as it controls the precipitation phase, as well as snow accumulation and snowmelt. Hydrological modelling in mountain regions like the Alps needs high‐resolution temperature fields as input, preferably at sub‐daily time steps. The estimation of such temperature fields is challenging due to the spatio‐temporal variability of environmental lapse rates (i.e. the decreasing of temperature with altitude) associated to complex topography. In this study, 10 years (2000–2009) of data from about 200 temperature stations were interpolated at 0, 6, 12 and 18 h Universal Time Coordinated (UTC) over a 1‐km resolution grid covering a window of 71 500 km2in the Northern French Alps. Three different kriging methods were tested. Kriging with elevation as external drift gave the best results in terms of mean absolute error, root mean square error and kriging standard deviation. Adding potential solar radiation as an additional external variable did not improve significantly the interpolation results. Prediction errors showed dependence on elevation and season, as well as on the time of interpolation, with globally better results in summer and daytime than in winter and night‐time. Despite some shortcomings that are discussed in the paper, the interpolated temperature fields look promising for further snowmelt and snow cover dynamics modelling studies. Copyright © 2012 John Wiley & Sons, Ltd.
Variants at chromosome 20 (ASIP locus) and melanoma risk
Authors: Maccioni Livia , Rachakonda P. Sivaramakrishna , Scherer Dominique , Bermejo Justo Lorenzo , Planelles Dolores , Requena Celia , Hemminki Kari , Nagore Eduardo , Kumar Rajiv
Published: May 2012

Agouti signaling protein (ASIP) locus on chromosome 20q11 is implicated, as shown by genome‐wide association studies, in phenotype variation and melanoma risk. We genotyped 837 melanoma cases and 1,154 controls for 21 single nucleotide polymorphisms (SNPs) informative for 495 polymorphisms at the locus. Our data showed an increased risk of melanoma (odds ratio [OR] 1.27, 95% confidence interval [95% CI] 1.03–1.57) in carriers of the rs4911414 variant, located 120 kb upstream of ASIP. The main effect of rs4911414, as reported previously, was in tandem with a 10 kb adjacent polymorphism rs1015362; two constituted risk‐associated haplotype/diplotype. Except for rs1015363, none of the 12 tagging SNPs, genotyped to cover 239.9 kb region with polymorphisms linked to rs4911414 and rs1015362, were associated with melanoma. Our data confirmed a previous association of melanoma risk (OR 1.82, 95% CI 1.37–2.41) with rs4911442, located in intron 5 of the nuclear receptor coactivator 6 (NCOA6) gene. The rs910871, one of the six variants, genotyped to cover NCOA6, showed an association with melanoma risk (OR 1.33, 95% CI 1.04–1.70). Both, rs4911442 and rs910871 were in moderate linkage with a, previously reported, risk‐associated rs910873 polymorphism. A haplotype from the variants within NCOA6 showed an association with risk of melanoma (OR 1.49, 95% CI 1.17–1.88). Interaction between risk‐associated polymorphisms and previously genotyped melanocortin receptor 1 (MC1R) variants, in our study, was not statistically significant. Nevertheless, the carriers of the variant alleles over the background of MC1R variants were at a higher risk than the carriers not enriched for MC1R variants. Our data confirmed the association of different variants at chromosome 20q11 with melanoma risk.
Chemometric evaluation of physicochemical properties of carbonated‐apatitic preparations by Fourier transform infrared spectroscopy
Authors: Otsuka Makoto , Papangkorn Kongnara , Baig Arif A. , Higuchi William I.
Published: May 2012

The purpose of this study was to develop a simple and quick method of evaluating the physicochemical properties of carbonated apatite preparations (CAP) as an index of the bioaffinity of implantable materials based on Fourier‐transformed‐infrared (IR) spectra by chemometrics. The wet‐synthesized CAPs contained various levels of carbonate content (CO3), and were analyzed microstrain parameter (MS), crystallite size parameter (CP), specific surface area (Sw), CO3, and solubility parameter (pKHAP) using by X‐ray powder diffraction, nitrogen gas adsorption, IR, and UV absorption. The IR spectral results of CAPs suggested that the peak intensities of CAP reflected the physicochemical properties of the samples. The IR data sets were calculated to obtain calibration models evaluating the physicochemical properties of CAPs by a partial least squares regression analysis (PLS). As validation of the calibration model, physicochemical properties of CAP could be evaluated based on validation IR data sets of independent samples, and those values had sufficient accuracy. The regression vector of each calibration model suggested that the physicochemical properties of CAP, such as CO3, Sw, MS, CP, and pKHAP, were affected by phosphate, hydroxyl, and carbonate groups. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Degradable amorphous scaffolds with enhanced mechanical properties and homogeneous cell distribution produced by a three‐dimensional fiber deposition method
Authors: Sun Yang , Finne‐Wistrand Anna , Albertsson Ann‐Christine , Xing Zhe , Mustafa Kamal , Hendrikson Wim J. , Grijpma Dirk W. , Moroni Lorenzo
Published: May 2012

The mechanical properties of amorphous, degradable, and highly porous poly(lactide‐co‐caprolactone) structures have been improved by using a 3D fiber deposition (3DF) method. Two designs of 3DF scaffolds, with 45° and 90° layer rotation, were printed and compared with scaffolds produced by a salt‐leaching method. The scaffolds had a porosity range from 64% to 82% and a high interconnectivity, measured by micro‐computer tomography. The 3DF scaffolds had 8–9 times higher compressive stiffness and 3–5 times higher tensile stiffness than the salt‐leached scaffolds. There was a distinct decrease in the molecular weight during printing as a consequence of the high temperature. The chain microstructure was, however, not affected; the glass transition temperature and the decomposition temperature were constant. Human OsteoBlast‐like cells were cultured in vitro and the cell morphology and distribution were observed by scanning electron microscopy and fluorescence microscopy. The cell distribution on the 3DF scaffolds was more homogeneous than the salt‐leached scaffolds, suggesting that 3DF scaffolds are more suitable as porous biomaterials for tissue engineering. These results show that it is possible to design and optimize the properties of amorphous polymer scaffolds. The 3DF method produce amorphous degradable poly(lactide‐co‐caprolactone) that are strong and particularly suitable for cell proliferation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:2739–2749, 2012.
Experimental and computational analysis of cellular interactions with nylon‐3‐bearing substrates
Authors: Liu Runhui , Vang Kang Z. , Kreeger Pamela K. , Gellman Samuel H. , Masters Kristyn S.
Published: May 2012

The ability to design biomaterials that interact with biological environments in a predictable manner necessitates an improved understanding of how surface chemistry influences events such as protein adsorption and cell adhesion. In this work, we examined mechanisms governing the interactions between 3T3 fibroblasts and nylon‐3 polymers, which have a protein‐like polyamide backbone and are highly amenable to tuning of chemical and physical properties. Protein adsorption and cell adhesion to a library of nylon‐3 polymers were characterized and analyzed by partial least squares regression. This analysis revealed that specific chemical features of the nylon‐3 polymers correlated with the extent of protein adsorption, which, in turn, correlated with cell adhesion in a serum‐containing environment. In contrast, in a serum‐free environment, cell adhesion could be predicted solely from chemical properties. Enzymatic treatments of 3T3 cells before plating indicated that proteins bound to the cell surface mediated cell‐nylon‐3 polymer interactions under serum‐free conditions, with additional analysis suggesting that cell‐associated fibronectin played a dominant role in adhesion in the absence of serum. The mechanistic insight gained from these studies can be used to inform the design of new polymer structures in addition to providing a basis for continued development of nylon‐3 copolymers for tissue engineering applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:2750–2759, 2012.