bluuebunny/crossref_metadata_2025 huggingface dataset:
Quasiclassical trajectory study of the rotational distribution for the O+NO(v = 0) fundamental vibrational excitation
Authors: Galvão B. R. L. , Corzo‐Espinoza J. A. , Caridade P. J. S. B. , Varandas A. J. C.
Published: April 2011

Quasiclassical trajectories have been run to study the fundamental one‐quantum vibrational transition formed from collisions of ground‐state nitric oxide with atomic oxygen at temperatures of 500, 750, and 1000 K. Two adiabatic potential energy surfaces of different symmetry (2A′ and 2A″ of NO2) have been utilized. The rate constant for the title process is given along with the rotational distributions, and the results shown to corroborate previous atmospheric models that describe the nascent state by a Maxwell–Boltzmann distribution at the local temperature. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 345–352, 2011
Phenolysis and aminolysis of 4‐nitrophenyl and 2,4‐dinitrophenyl S‐methyl thiocarbonates in aqueous ethanol
Authors: Castro Enrique A. , Aliaga Margarita E. , Cepeda Marjorie , Santos José G.
Published: April 2011

The reactions of S‐methyl O‐(4‐nitrophenyl) thiocarbonate (1) and S‐methyl O‐(2,4‐dinitrophenyl) thiocarbonate (2) with a series of secondary alicyclic (SA) amines and phenols are subjected to a kinetic investigation. Under nucleophile excess, pseudo‐first‐order rate coefficients (kobs) are obtained. Plots of kobs against the free nucleophile concentration at constant pH are linear with slopes kN. The Brønsted plots (log kN vs. nucleophile pKa) for the reactions are linear with slope (β) values in the 0.5–0.7 range, in accordance with concerted mechanisms. Comparison of the SA aminolysis of 1 with the same one carried out in water shows that the change of solvent from water to aqueous ethanol destabilizes the zwitterionic tetrahedral intermediate, changing the mechanism from stepwise to concerted. This destabilization is greater than that due to the change from SA amines to quinuclidines. For the phenolysis reactions, the kN values in aqueous ethanol are smaller than those for the same reactions in water. Considering that the nucleophile is an anion, this result is unexpected because the anion should be more stabilized in the more polar solvent. This result is explained by the facts that the phenoxide reactant has a negative charge that is delocalized in the aromatic ring and the transition state is highly polar. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 353–358, 2011
Applications of mass spectrometry to metabolomics and metabonomics: Detection of biomarkers of aging and of age‐related diseases
Authors: Mishur Robert J. , Rea Shane L.
Published: April 2011

Every 5 years or so new technologies, or new combinations of old ones, seemingly burst onto the science scene and are then sought after until they reach the point of becoming commonplace. Advances in mass spectrometry instrumentation, coupled with the establishment of standardized chemical fragmentation libraries, increased computing power, novel data‐analysis algorithms, new scientific applications, and commercial prospects have made mass spectrometry‐based metabolomics the latest sought‐after technology. This methodology affords the ability to dynamically catalogue and quantify, in parallel, femtomole quantities of cellular metabolites. The study of aging, and the diseases that accompany it, has accelerated significantly in the last decade. Mutant genes that alter the rate of aging have been found that increase lifespan by up to 10‐fold in some model organisms, and substantial progress has been made in understanding fundamental alterations that occur at both the mRNA and protein level in tissues of aging organisms. The application of metabolomics to aging research is still relatively new, but has already added significant insight into the aging process. In this review we summarize these findings. We have targeted our manuscript to two audiences: mass spectrometrists interested in applying their technical knowledge to unanswered questions in the aging field, and gerontologists interested in expanding their knowledge of both mass spectrometry and the most recent advances in aging‐related metabolomics. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 31:70–95, 2012
Vertical response of pile raft foundations subjected to tunneling‐induced ground movements in layered soil
Authors: Huang Maosong , Mu Linlong
Published: April 2011

A simplified analysis method has been developed to estimate the vertical movement and load distribution of pile raft foundations subjected to ground movements induced by tunneling based on a two‐stage method. In this method, the Loganathan–Polous analytical solution is used to estimate the free soil movement induced by tunneling in the first stage. In the second stage, composing the soil movement to the pile, the governing equilibrium equations of piles are solved by the finite difference method. The interactions between structural members (such as pile–soil, pile–raft, raft–soil, and pile–pile) are modeled based on the elastic theory method of a layered half‐space. The validity of the proposed method is verified through comparisons with some published solutions for single piles, pile groups, and pile rafts subjected to ground movements induced by tunneling. Good agreements between these solutions are demonstrated. The method is also used for a parametric study to develop a better understanding of the behavior of pile rafts influenced by tunneling operation in layered soil foundations. Copyright © 2011 John Wiley & Sons, Ltd.
Patient‐perceived outcomes of the AdVance sling up to 40 months post procedure
Authors: Suskind Anne M. , Bernstein Bruce , Murphy‐Setzko Marlene
Published: April 2011

Aims

The objective of this study was to determine patient‐perceived outcomes of the AdVance sling over 40 months and to determine if results were durable over time.

Methods

This study represents a retrospective chart review of a single‐surgeon's experience with the AdVance sling paired with a follow‐up 5 question telephone survey performed in April 2010. The telephone survey consisted of 2 validated questions pertaining to patient satisfaction (the PGI‐I and the PGI‐S) along with 3 additional questions pertaining to number of pads per day (PPD) used, additional therapies tried, and whether or not the patient would recommend the procedure to a friend. Ordinal and non‐normally distributed variables were analyzed via rank order correlation (Spearman's rho) and the association between the number of pads per day used at the time of telephone survey and progressing time since sling procedure was plotted with linear regression analysis.

Results

The surgeon performed a total of 44 AdVance sling procedures from 2006 to April 2011. 42 charts were available for review and 36 (85.7%) patients were reached via telephone. Average patient age was 63.64 years and average time in months since sling procedure was 18.76. Average number of PPD used was 2.11 preoperatively, 0.38 at the one month post‐operative visit, and 1.67 at time of the telephone survey. Additionally, advancing time since sling operation correlated with higher numbers of PPD. 34/36 patients would recommend the procedure to a friend.

Conclusion

Despite patient satisfaction with the sling procedure, our data show that patients were using an increasing number of PPD as time from sling procedure advanced. This is important information for patients and physicians to consider when choosing this procedure. Neurourol. Urodynam. 30:1267–1270, 2011. © 2011 Wiley‐Liss, Inc.
Reproducibility of urodynamic filling sensation at weekly interval in healthy volunteers and in women with detrusor overactivity
Authors: Van Meel Tom David , Wyndaele Jean‐Jacques
Published: April 2011

Aims

To evaluate the reproducibility of bladder sensation during standardized filling cystometry in female volunteers and overactive bladder (OAB) patients, repeated with weekly interval.

Methods

We recruited 13 female nulliparous volunteers (age 21–47) and 17 female patients with OAB between (age 18–72). They participated in three investigation periods, each separated by 7 days to assess reproducibility of sensation related to standardized cystometry. Subjects were asked to report all sensations they felt during bladder filling.

Results

The previously described pattern of sensation was reported during bladder filling in all. Consecutive sensations corresponded to statistically higher bladder volumes. Volumes, at which different sensations of bladder filling were reported, were significantly higher in controls than in OAB patients [first sensation of filling (FSF) P = 0.003, first desire to void (FDV) P < 0.0001, and strong desire to void (SDV) P < 0.0001]. The sensation/volume ratios were significantly higher in patients with OAB than in the healthy volunteers: FSF occurred at mean 46% and FDV at mean 73% of SDV in OAB patients, compared to 36% and 64% in healthy volunteers. Sensations proved highly reproducible when determined with weekly interval.

Conclusions

Our data demonstrate that cystometric filling sensation determined in a standardized way with weekly interval is highly reproducible in healthy and in OAB patients. This finding has, in our opinion, clinical importance as it shows that the technique is reliable both for a sensory evaluation of the LUT as to study influence of treatment aimed at changing this sensation. Neurourol. Urodynam. Neurourol. Urodynam. 30: 1586–1590, 2011. © 2011 Wiley Periodicals, Inc.
MR‐visible lipids and the tumor microenvironment
Authors: Delikatny E. James , Chawla Sanjeev , Leung Daniel‐Joseph , Poptani Harish
Published: April 2011

MR‐visible lipids or mobile lipids are defined as lipids that are observable using proton MRS in cells and tissues. These MR‐visible lipids are composed of triglycerides and cholesterol esters that accumulate in neutral lipid droplets, where their MR visibility is conferred as a result of the increased molecular motion available in this unique physical environment. This review discusses the factors that lead to the biogenesis of MR‐visible lipids in cancer cells and in other cell types, such as immune cells and fibroblasts. We focus on the accumulations of mobile lipids that are inducible in cultured cells by a number of stresses, including culture conditions, and in response to activating stimuli or apoptotic cell death induced by anticancer drugs. This is compared with animal tumor models, where increases in mobile lipids are observed in response to chemo‐ and radiotherapy, and to human tumors, where mobile lipids are observed predominantly in high‐grade brain tumors and in regions of necrosis. Conducive conditions for mobile lipid formation in the tumor microenvironment are discussed, including low pH, oxygen availability and the presence of inflammatory cells. It is concluded that MR‐visible lipids appear in cancer cells and human tumors as a stress response. Mobile lipids stored as neutral lipid droplets may play a role in the detoxification of the cell or act as an alternative energy source, especially in cancer cells, which often grow in ischemic/hypoxic environments. The role of MR‐visible lipids in cancer diagnosis and the assessment of the treatment response in both animal models of cancer and human brain tumors is also discussed. Although technical limitations exist in the accurate detection of intratumoral mobile lipids, early increases in mobile lipids after therapeutic interventions may be useful as a potential biomarker for the assessment of treatment response in cancer. Copyright © 2011 John Wiley & Sons, Ltd.
Quantitative assessment of central nervous system disorder induced by prenatal X‐ray exposure using diffusion and manganese‐enhanced MRI
Authors: Saito Shigeyoshi , Aoki Ichio , Sawada Kazuhiko , Suhara Tetsuya
Published: April 2011

Prenatal radiation exposure induces various central nervous system (CNS) disorders depending on the dose, affected region and gestation period. The goal of this study was to assess noninvasively a CNS development disorder induced by prenatal X‐ray exposure using quantitative manganese‐enhanced MRI (MEMRI) as well as apparent diffusion coefficient (ADC) and transverse relaxation time (T2) maps in comparison with immunohistological staining. The changes in ΔR1 (increase in the longitudinal relaxation rate (R1) from before and after MnCl2 administration.) induced by the Mn2+ contrast agent were evaluated in the CNS of normal and prenatally irradiated rats. ADC and T2 were also compared with the histological results obtained using hematoxylin and eosin (to estimate cell density), activated caspase‐3 (apoptotic cells) and glial fibrillary acidic protein (proliferation of astrocytes/astroglia). We found the following: (i) the decreased Mn2+ uptake (indicated by a smaller ΔR1) for radiation‐exposed rats was predominantly correlated with a decrease in cell viability (apoptotic cytopathogenicity) and CNS cell density after prenatal radiation exposure; (ii) the longer T2 and ADC were associated with a decrease in CNS cell density and apoptotic alteration after radiation exposure. In addition to the slight proliferation of astroglia (+58%), there was a substantial decrease in cell density (−78%) and an excessive increase in apoptotic cells (+613%) in our prenatal radiation exposure model. The results suggest that MEMRI in the prenatal X‐ray exposure model predominantly reflected the decrease in cell density and viability rather than the proliferation of astroglia. In conclusion, quantitative MEMRI with ADC/T2 mapping provides objective information for the in vivo assessment of cellular level alterations by prenatal radiation exposure, and has the potential to be used as a standard approach for the evaluation of the cellular damage of radiotherapy. Copyright © 2011 John Wiley & Sons, Ltd.
Parahydrogen‐induced polarization (PHIP) hyperpolarized MR receptor imaging in vivo: a pilot study of 13C imaging of atheroma in mice
Authors: Bhattacharya Pratip , Chekmenev Eduard Y. , Reynolds Wanda F. , Wagner Shawn , Zacharias Niki , Chan Henry R. , Bünger Rolf , Ross Brian D.
Published: April 2011

MR techniques using hyperpolarized 13C have successfully produced examples of angiography and intermediary metabolic imaging, but, to date, no receptor imaging has been attempted. The goal of this study was to synthesize and evaluate a novel hyperpolarizable molecule, 2,2,3,3‐tetrafluoropropyl 1‐13C‐propionate‐d2,3,3 (TFPP), for the detection of atheromatous plaques in vivo. TFPP binds to lipid bilayers and its use in hyperpolarized MR could prove to be a major step towards receptor imaging. The precursor, 2,2,3,3‐tetrafluoropropyl 1‐13C‐acrylate‐d2,3,3 (TFPA), binds to 1,2‐dimyristoylphosphatidylcholine lipid bilayers with a 1.6‐ppm chemical shift in the 19F MR spectrum. This molecule was designed to be hyperpolarized through the addition of parahydrogen to the 13C‐acrylate moiety by parahydrogen‐induced polarization. TFPA was hyperpolarized to TFPP to an extent similar to that of the hydroxyethylacrylate to hydroxyethylpropionate transition: 17 ± 4% for TFPP versus 20% for hydroxyethylpropionate; T1 relaxation times (45 ± 2 s versus 55 ± 2 s) were comparable and the hyperpolarized properties of TFPP were characterized. Hydroxyethylacrylate, like TFPA, has a chemical structure with an acrylate moiety, but does not contain the lipid‐binding tetrafluoropropyl functional group. Hyperpolarized TFPP binds to the lipid bilayer, appearing as a second, chemically shifted 13C hyperpolarized MR signal with a further reduction in the longitudinal relaxation time (T1 = 21 ± 1 s). In aortas harvested from low‐density lipoprotein receptor knock‐out mice fed with a high‐fat diet for 9 months, and in which atheroma is deposited in the aorta and heart, TFPP showed greater binding to lipid on the intimal surface than in control mice fed a normal diet. When TFPP was hyperpolarized and administered in vivo to atheromatous mice in a pilot study, increased binding was observed on the endocardial surface of the intact heart compared with normally fed controls. Hyperpolarized TFPP has bio‐sensing specificity for lipid, coupled with a 42 000‐fold sensitivity gain in the MR signal at 4.7 T. Binding of TFPP with lipids results in the formation of a characteristic second peak in MRS. TFPP therefore has the potential to act as an in vivo molecular probe for atheromatous plaque imaging and may serve as a model of receptor‐targeted bio‐imaging with enhanced MR sensitivity. Copyright © 2011 John Wiley & Sons, Ltd.
Neumann‐Neumann methods for a DG discretization on geometrically nonconforming substructures
Authors: Dryja Maksymilian , Galvis Juan , Sarkis Marcus
Published: April 2011

A discontinuous Galerkin discretization for second order elliptic equations with discontinuous coefficients in 2D is considered. The domain of interest Ω is assumed to be a union of polygonal substructures Ωi of size O(Hi). We allow this substructure decomposition to be geometrically nonconforming. Inside each substructure Ωi, a conforming finite element space associated to a triangulation
\documentclass{article} \usepackage{mathrsfs} \usepackage{amsmath} \pagestyle{empty} \begin{document} \begin{align*} {\mathcal{T}}_{h_i}(\Omega_i)\end{align*}\end{document}
is introduced. To handle the nonmatching meshes across ∂Ωi, a discontinuous Galerkin discretization is considered. In this article, additive and hybrid Neumann‐Neumann Schwarz methods are designed and analyzed. Under natural assumptions on the coefficients and on the mesh sizes across ∂Ωi, a condition number estimate
\documentclass{article} \usepackage{mathrsfs} \usepackage{amsmath} \pagestyle{empty} \begin{document} \begin{align*} C(1 + \max_i\log \frac{H_i}{h_i})^2\end{align*}\end{document}
is established with C independent of hi, Hi, hi/hj, and the jumps of the coefficients. The method is well suited for parallel computations and can be straightforwardly extended to three dimensional problems. Numerical results are included. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2012
Preparing iPP/HDPE/CB functionally gradient materials: influence factors of components and processing
Authors: Gao Yong‐Juan , Liu Zheng‐Ying , Yin Chao‐Lu , Huang Shi‐Lin , Yang Ming‐Bo
Published: April 2011

In this work, gradient materials with low electrical resistivity were prepared by compounding isotactic polypropylene (iPP)/high density polyethylene (HDPE) blends with carbon black (CB) through extruding and injection molding. Contact angle measurements and morphology measurements showed that the CB particles were selectively located in HDPE phase and the final composites had a gradient structure that the HDPE/CB phase exhibited different morphologies in the skin layer and core layer of the composites under different processing procedures. The main factors influencing the formation of the functional gradient materials (FGM), including screw speed during extruding, iPP types and CB contents were discussed. They affect the phase morphology by shear stress, the restoration of HDPE phase, and the viscosity ratio of polymer blends, respectively. In conclusion, iPP/HDPE/CB FGM could be formed easily in the composites blending with the iPP type with narrow molecular weight distribution (MWD) and higher CB content extruded at higher screw speed. The electrical properties of iPP/HDPE/CB composites were studied and the results showed that screw speed in extrusion significantly influenced the percolation curve and electrical property of the final composites. Copyright © 2011 John Wiley & Sons, Ltd.
Copolymer of star poly(epsilon‐caprolactone) and polyglycidols as potential carriers for hydrophobic drugs
Authors: Mou Liang , Chen Niancao , Zhu Kun , Chen Yuanwei , Luo Xianglin
Published: April 2011

Amphiphilic star shape poly(ε‐caprolactone)‐b‐hyperbranched polyglycidol (sPCL‐HPG) were synthesized and used to investigate micell formation and to encapsulate hydrophobic drugs. The synthesis of sPCL‐HPG copolymers was carried out by using sPCL as macroinitiator for the ensuing of hypergrafting reaction with glycidols. 1H‐NMR and FTIR were used to characterize sPCL‐b‐HPG structures. The self‐assembled structure of the sPCL‐HPG was characterized by scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The size and size dispersities of micelles were measured by dynamic light scattering DLS. Critical micelle concentration (CMC) was determined using pyrene as fluorescent probe. Hydrophobic methyl red was encapsulated in sPCL‐HPG micelles to illustrate hydrophobic drug loading. The copolymer micelles were used to enhance paclitaxel solubility. The results showed that hydrophobic drugs could be encapsulated in the sPCL‐HPG micelles. The paclitaxel solubility in the micelles of 5 wt% of sPCL23‐HPG170 got to 168 µg/ml. sPCL‐HPG, which have biodegrability and hydrophobicity at PCL part and smaller size of HPG fragments while maintaining the total repeating units of glycidols, provide an alternative choice of carriers for poorly soluble drugs. Copyright © 2011 John Wiley & Sons, Ltd.
Film formation of poly (methyl methacrylate) latex with pyrene functional poly (divinylbenzene) microspheres prepared by click chemistry
Authors: Uğur Şaziye , Yargı Önder , Durmaz Yasemin Yüksel , Karagöz Bünyamin , Bıçak Niyazi , Yağcı Yusuf , Pekcan Önder
Published: April 2011

This work reports on the application of steady state fluorescence (SSF) technique for studying film formation from poly(methyl methacrylate) (PMMA) latex and poly(divinylbenzene) (PDVB) microsphere composites. Pyrene (P) functionalized PDVB cross‐linked spherical microspheres with diameters of 2.5 μm were synthesized by using precipitation polymerization technique followed by click coupling reaction. The diameter of the PMMA particles prepared by emulsion polymerization were in the range of 0.5–0.7 μm. PMMA/PDVB composite films were then prepared by physically blending of PMMA latex with PDVB microspheres at various composition (0, 1, 3, 5, 10, 20, 40, and 60 wt%). After drying, films were annealed at elevated temperatures above Tg of PMMA ranging from 100 to 270°C for 10 min time intervals. Evolution of transparency of the composite films was monitored by using photon transmission intensity, Itr. Monomer (IP) and excimer (IE) fluorescence intensities from P were measured after each annealing step. The possibility of using the excimer‐to‐monomer intensity ratio (IE/IP) from PDVB microparticles as a measure of PMMA latex coalescence was demonstrated. Diffusion of the PMMA chains across the particle–particle interfaces dilutes the dyes, increasing their separation. The film formation stages of PMMA latexes were modeled by monitoring the IE/IP ratios and related activation energies were determined. There was no observable change in activation energies confirming that film formation behavior is not affected by varying the PDVB composition in the studied range. SEM images of PMMA/PDVB composites confirmed that the PMMA particles undergo complete coalescence forming a continuous phase in where PDVB microspheres are dispersed. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Experimental study of flexible injection to manufacture parts of strong curvature
Authors: Causse Philippe , Ruiz Edu , Trochu François
Published: April 2011

Flexible injection (FI) is a new process for the manufacture of high performance composites, which consists of injecting a thermosetting resin through a fibrous reinforcement contained in the lower chamber of a double cavity mold. Resin is injected in the lower cavity, which is sealed by a membrane, and then a compaction fluid is injected in the upper chamber to compress the reinforcement. This new composite manufacturing technique, which allows a limited and controlled deformation of the flexible membrane during processing, was shown to be very effective in reducing filling times in the case of planar or slightly curved geometries. In the present study, flexible injection is applied to strongly curved parts, namely here a composite rectangular panel with two 90° corners. After setting up an experimental procedure to produce the stair‐shaped components out of fiberglass and vinylester resin, longitudinal cross‐sections of the parts are analyzed to assess the quality of the final product in both the flat and curved zones. This characterization method allows detecting manufacturing defects such as thickness gradients or resin‐rich zones. Such defects are likely to induce geometrical deformations of the component and may decrease its mechanical performance. Therefore they ought to be minimized to improve the overall quality of the part. Modifications of the manufacturing procedure are proposed in this article to decrease the importance of process‐induced defaults and improve the performance of the flexible injection. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Elastic buckling of circular annular plate reinforced with carbon nanotubes
Authors: Jam J. E. , Kia S. M. , Pour A. G. , Emdadi M.
Published: April 2011

The buckling analysis of circular annular plate reinforced by carbon nanotubes (CNTs) subjected to compressive and torsional loads with various axially symmetric boundary conditions are studied in this paper. The developed model is based on the classical laminated plate theory (CLPT). The Mori‐Tanaka method is employed to calculate the effective elastic modulus of composites having aligned oriented straight CNTs. The eigenvalues of the problem are obtained by means of an analytical approach based on the optimized Rayleigh‐Ritz method. The effects of CNTs orientation angles, edge conditions, geometric ratio of plate and agglomeration of the randomly oriented straight CNTs are investigated on the critical buckling loads. Extensive studies validity of the results based on available data have been carried out prior to the presentation of salient results of this analysis. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Modeling the effective properties and thermomechanical behavior of SMA‐SMP multifunctional composite laminates
Authors: Jarali Chetan S. , Raja S. , Kiefer Björn
Published: April 2011

The research work presents the modeling of effective properties and thermo‐mechanical behavior of shape memory fiber (SMF) and shape memory polymer (SMP) composite laminates using micromechanical approaches based on the method of mixtures (MOM) and method of cells (MOC). The fiber is made of a nickel‐titanium (Ni‐Ti) shape memory alloy (SMA), while the matrix consists of a shape memory thermoset epoxy polymer (SMP). The use of an SMP matrix provides large strain compatibility with the SMA fiber, while being active at high temperatures without losing its elastic properties. Additionally, the SMP matrix is also able to produce similar pseudoelastic and shape memory effects, which are noticed in SMAs. In the analysis, a two step homogenization scheme is followed. In the first step the effective properties of each layer are determined via a micromechanics approach with iso‐strain conditions. In the second step the effective properties of the SMF‐SMP composite are computed making a thin plate theory assumption, which takes into account the transverse shear deformations. The possible elastic couplings for SMF‐SMP laminates are discussed, and the laminate force and moment resultants are computed for various laminate configurations. The analysis takes into account the effects of phase transformations and the resulting change in the fiber–matrix modulus. The results have been compared by considering different fiber volume fractions, temperatures, fiber orientations, and lamina stacking sequences. The results show that adaptive SMA‐SMP composites laminates can be developed that provide shape controllability via tunable laminate stiffnesses leading to optimal response. Furthermore, the work presents the necessary framework for a reliable and efficient analysis of SMA‐SMP laminates for practical applications. The theory can be directly used in established plate and shell formulations of finite element analysis. Finally, the variations in force and moment resultants with respect to fiber orientations and stacking sequences are presented, which are useful to study the bending and buckling characteristics of active composites for shape control of adaptive structures. The work concludes that efficient adaptive laminate development for high performance composite applications, exhibiting large shape adaptivity, high stresses, and increased stiffness, are feasible as compared to SMA composites without active matrix. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Studies on drying and swelling of PAAm‐NIPA composites in various compositions
Authors: Akın Evingür Gülşen , Pekcan Önder
Published: April 2011

The steady‐state fluorescence technique was introduced for studying the drying and swelling of disc‐shaped PAAm‐NIPA composites. Disc‐shaped gels were formed with various acrylamides (AAm) and N‐isopropylacrylamides (NIPA) by free radical crosslinking copolymerization in water. Composites were prepared with pyranine (Py) doped as a fluorescence probe. Scattered light, Isc, and fluorescence intensities, I, were monitored during drying of these gels. The fluorescence intensity of pyranine increased and decreased as drying and swelling time increased respectively for all samples. The Stern‐Volmer equation combined with moving boundary and Li‐Tanaka models were used to explain the behavior of I during drying and swelling, respectively. It was found that the desorption coefficient, D, increased as NIPA contents were increased for a given temperature during drying. However, the cooperative diffusion coefficient, D0, increased as NIPA contents were decreased during swelling at a given temperature. Supporting gravimetrical and volumetric experiments were also carried out during drying and swelling of PAAm‐NIPA composites. It was observed that NIPA contents affect the drying and swelling process. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Classification and identification of damage mechanisms in polyethylene self‐reinforced laminates by acoustic emission technique
Authors: Wang Xu , Zhang Hui‐Ping , Yan Xiong
Published: April 2011

The objective of present study is to classify and identify damage mechanisms in polyethylene(PE) self‐reinforced composites by acoustic emission (AE) technique. Model specimens including LDPE resin, [90°]laminate, single fiber composite, fiber bundle composite, and [±45°] laminates are fabricated to obtain expected damage mechanisms during tensile testing. First, mechanical behaviors and corresponding AE response of model specimens are studied to validate damage mechanisms in UHMWPE/LDPE laminates. Second, relationship among AE descriptors is investigated by hierarchical cluster analysis, and AE signals are classified by k‐means cluster analysis. Correlations between damage mechanisms and AE are established in terms of amplitude, duration, and peak frequency of AE signals. Finally, an artificial neural network is created and trained by various optimal algorithms to identify damage mechanisms. The results reveal that typical damage mechanisms in PE self‐reinforced composite can be classified in terms of the similarity between AE signals and identified by trained artificial neural network. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Exposure to CYP3A4‐inducing and CYP3A4‐non‐inducing antiepileptic agents and the risk of fractures
Authors: Schelleman Hedi , Pollard John R. , Newcomb Craig , Markowitz Clyde E. , Bilker Warren B. , Leonard Mary B. , Hennessy Sean
Published: April 2011

Purpose

To evaluate whether exposure to Cytochrome P450, family 3, subfamily A, polypeptide 4 (CYP3A4)‐inducing antiepileptics increases fracture risk compared to CYP3A4‐non‐inducing antiepileptics.

Methods

We performed a retrospective cohort study of initiators of antiepileptic agents using a UK medical record database (The Health Improvement Network) from 1995 to 2007. We considered an antiepileptic user an initiator if he or she had not received a prescription for an antiepileptic agent within the first year after entry in the database. Proportional hazards regression was used to calculate hazard ratios for fracture during long‐term (≥6 months) exposure to CYP3A4 inducing versus CYP3A4 non‐inducing antiepileptics.

Results

We identified 4077 initiators of CYP3A4‐inducing antiepileptics and 6433 initiators of CYP3A4‐non‐inducing antiepileptics with at least 6 months of antiepileptic exposure. During 6006 person‐years exposed to CYP3A4‐inducing antiepileptics, 118 fractures were identified for an incidence rate of 1.96 (95% confidence interval (CI): 1.63–2.35) fractures per 100 person‐years. During 7184 person‐years exposed to CYP3A4‐non‐inducing antiepileptics, 127 fractures were identified, for an incidence rate of 1.77 (95% CI: 1.47–2.10) fractures per 100 person‐years. The adjusted hazard ratio for CYP3A4‐inducing antiepileptic versus CYP3A4‐non‐inducing antiepileptic was 1.21 (95% CI: 0.93–1.56). No duration–response relationship was evident.

Conclusions

Our results do not support the hypothesis that CYP3A4 induction by antiepileptic agents increases the fracture risk. Further research will be needed to evaluate whether mechanisms other than CYP3A4 induction might explain some of the elevated risk of fractures associated with long‐term use of antiepileptic agents. Copyright © 2011 John Wiley & Sons, Ltd.
Variation in initiating secondary prevention after myocardial infarction by hospitals and physicians, 1997 through 2004
Authors: Margulis Andrea V. , Choudhry Niteesh K. , Dormuth Colin R. , Schneeweiss Sebastian
Published: April 2011

Purpose

Myocardial infarction (MI) survivors benefit from receiving secondary prevention, including beta‐blockers, angiotensin‐blocking agents, and statins, as recommended by guidelines. Compliance with these guidelines is suboptimal. We sought to describe the initiation of secondary prevention in MI survivors, and to describe the variation in initiation by discharging the hospital, the physician, and the physician “responsible” for secondary prevention prescribing decisions in British Columbia in 1997–2004.

Methods

We assembled a cohort of 28 613 patients discharged alive from the hospital after their first MI and were not readmitted within 30 days. Physicians responsible for prescribing post‐MI secondary prevention medications were identified as the physicians prescribing the greatest number of cardiac medications (post‐discharge cardiac prescribers). We used multilevel logistic regression to assess the variation in drug initiation at discharging hospital, discharging physician, and post‐discharge cardiac prescriber levels, which were adjusted for patient and provider characteristics during the study period.

Results

Beta‐blockers initiation increased from 56 to 71% over the 8‐year study period; angiotensin‐converting enzyme/angiotensin II receptor blocker initiation increased from 37 to 70%, and statin initiation increased from 22 to 66% (0–28% for high‐potency statins). The probability for initiating an average patient with the study drugs varied widely in age–sex‐adjusted models at the hospital and physician levels. Further adjustment did not meaningfully change findings. The variation was largest for statins. The maximum between‐provider variance was found for high‐potency statins in 2003–2004 at the post‐discharge cardiac prescriber level.

Conclusions

Study‐drug initiation is increasing among MI survivors, but the variation in initiation is wide between discharging hospitals and physicians. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of amphiphilic ABC triblock copolymers by single electron transfer nitroxide radical coupling reaction in tetrahydrofuran
Authors: Lin Wencheng , Jing Rongkuan , Wang Guowei , Huang Junlian
Published: April 2011

A series of ABC triblock copolymers, that is, polyisoprene‐block‐polystyrene‐block‐poly(ethylene oxide) (PI‐PS‐PEO), PI‐block‐poly(tert‐butyl acrylate)‐block‐PEO (PI‐PtBA‐PEO), and PI‐block‐poly(acrylic acide)‐block‐PEO (PI‐PAA‐PEO) were obtained by combination of anionic technique, atom transfer radical polymerization (ATRP), and single electron transfer nitroxide coupling (SETNRC) reaction. Anionic polymerization of isoprene followed by end capping with ethylene oxide yielded hydroxyl‐terminated PI. After esterification, PI with Br end group was used as a macroinitiator to initiate the polymerization of styrene and tBA by ATRP that was then trapped by 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) group in PEO by SETNRC reaction rapidly with high efficiency in tetrahydrofuran at room temperature. The effect of reaction time and polymer chain length on SETNRC reaction was discussed in detail. In the presence of Cu0/tris[2‐(dimethylamino)ethyl]amine, SETNRC between PI‐PS‐Br and PEO‐TEMPO was carried out with the efficiency of up to 91.6% in 2 h. With the increase in polymer chain length, the efficiency decreased fleetly. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of H‐shaped A3BA3 copolymer by methyl‐2‐nitrosopropane induced single electron transfer nitroxide radical coupling
Authors: Zhang Zhongning , Wang Guowei , Huang Junlian
Published: April 2011

Amphiphilic H‐shaped [poly(ethylene oxide)]3‐polystyrene‐[poly(ethylene oxide)]3(PEO3‐PS‐PEO3) copolymer was synthesized by 2‐methyl‐2‐nitrosopropane (MNP) induced single electron transfer nitroxide radical coupling (SETNRC) using PEO3‐(PS‐Br) as a single precursor. First, the A3B star‐shaped precursor PEO3‐(PS‐Br) was synthesized by atom transfer radical polymerization (ATRP) using three‐arm star‐shaped PEO3‐Br as macro‐initiator. Then, in the presence of Cu(I)Br/Me6TREN, the bromide group at PS end was sequentially transferred into carbon‐centered radical by single electron transfer and then nitroxide radical by reacting with MNP in mixed solvents of dimethyl sulfoxide (DMSO)/tetrahydrofuran (THF), and in situ generated nitroxide radical could again capture another carbon‐centered radical by fast SETNRC to form target PEO3‐PS‐PEO3 copolymer. The MNP induced SETNRC could reach to a high efficiency of 90% within 60 min. After the product PEO3‐PS‐PEO3 was cleaved by ascorbic acid, the SEC results showed that there was about 30% fraction of product formed by single electron transfer radical coupling (SETRC) between carbon‐centered radicals. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Various brush polymers through ring opening metathesis polymerization and nitroxide radical coupling reaction
Authors: Cerit Nese , Cakir Nese , Dag Aydan , Sirkecioglu Okan , Durmaz Hakan , Hizal Gurkan , Tunca Umit
Published: April 2011

A 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO)‐terminated poly(ethylene glycol) (PEG) or ‐poly(ε‐caprolactone) (PCL) (PEG11‐TEMPO or PCL23‐TEMPO) is grafted as a side chain onto a ROMP‐generated polyoxanorbornene (PONB) main backbone with bromide pendant groups (PONB20‐Br) using the NRC click reaction to yield related the brush copolymers, PONB20‐g‐PEG11 or PONB20‐g‐PCL23 catalyzed by Cu(I), Cu(0), and N,N,N′,N″,N″‐pentamethyldiethylenetriamine in N,N‐dimethylformamide at room temperature. Additionally, a ROMP‐generated brush copolymer PONB9‐g‐poly(methyl methacrylate)24 (PMMA)24‐Cl was reacted with a PEG11‐TEMPO or a PCL23‐TEMPO precursor via the NRC click reaction to yield a corresponding brush terpolymer, PONB9‐g‐(PMMA24‐b‐PEG11) or PONB9‐g‐(PMMA24‐b‐PCL23) under a similar reaction condition described above. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Segmented polyurethanes derived from novel siloxane–carbonate soft segments for biomedical applications
Authors: Choi Taeyi , Masser Kevin A. , Moore Erica , Weksler Jadwiga , Padsalgikar Ajay , Runt James
Published: April 2011

A novel macrodiol based on mixed silicone and carbonate chemistries was synthesized and used as a soft segment precursor in the synthesis of two series of segmented polyurethane (PU) copolymers varying in hard segment content and soft segment molecular weight. The hard segments in these copolymers were derived from 4,4‐methylene diphenyl diisocyanate and 1,4‐butane diol. The phase transitions, microphase separation behavior, and mechanical properties of the copolymers were investigated using a variety of experimental methods. When compared with segmented PU copolymers having predominately poly(dimethyl siloxane) soft segments, these siloxane–carbonate soft segment copolymers exhibit enhanced intersegment mixing, and consequently relatively low mechanical modulus. With relatively low modulus and siloxane units in the soft phase, the siloxane–carbonate PUs have potential for use in cardiac and orthopedic biomedical applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
A new FcεRI receptor‐mimetic peptide (PepE) that blocks IgE binding to its high affinity receptor and prevents mediator release from RBL 2H3 cells
Authors: Sandomenico Annamaria , Monti Simona M. , Palumbo Rosanna , Ruvo Menotti
Published: April 2011

We have recently reported on a class of IgE‐binding peptides designed based on the crystallographic structure of the high affinity FcεRI. Peptides contain receptor key residues located within the two distinct binding sites for IgE and selectively bind IgE with an affinity ranging between 6 and 60 µM. We have here designed and characterized a new molecule containing the receptor loops C′–E and B–C and an optimized linker for joining them made of a Lys side chain and a β‐Ala. This new peptide shows an increased affinity (around 30 times) compared to the parent loop C′–E + B–C previously described, while retaining the same two‐site mechanism of binding and the same selectivity. It also blocks the binding of IgE to the cell‐anchored receptor and efficiently prevents histamine release from mast cells. These properties make the peptide a useful scaffold for the development of new anti‐allergic drugs. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
A defensin‐like antimicrobial peptide from the venoms of spider, Ornithoctonus hainana
Authors: Zhao Hongwen , Kong Yi , Wang Hanjin , Yan Tianhua , Feng Feifei , Bian Jianmin , Yang Yan , Yu Haining
Published: April 2011

The defensin‐like antimicrobial peptides have been characterized from various other arthropods including insects, scorpions, and ticks. But no natural spider defensin‐like antimicrobial peptides have ever been isolated from spiders, except couple of cDNA and DNA sequences of five spider species revealed by previous genomic study. In this work, a defensin‐like antimicrobial peptide named Oh‐defensin was purified and characterized from the venoms of the spider, Ornithoctonus hainana. Oh‐defensin is composed of 52 amino acid (aa) residues including six Cys residues that possibly form three disulfide bridges. Its aa sequence is MLCKLSMFGAVLGV PACAIDCLPMGKTGGSCEGGVCGCRKLTFKILWDKKFG. By BLAST search, Oh‐defensin showed significant sequence similarity to other arthropod antimicrobial peptides of the defensin family. Oh‐defensin exerted potent antimicrobial activities against tested microorganisms including Gram‐positive bacteria, Gram‐negative bacteria, and fungi. The cDNA encoding Oh‐defensin precursor was also cloned from the cDNA library of O. hainana. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Molecular modeling study of the opioid receptor interactions with series of cyclic deltorphin analogues
Authors: Ślusarz Magdalena J.
Published: April 2011

In this study, ten tetra‐ and heptapeptide analogues of deltorphin containing the urea bridges between residues 2 and 4 have been docked into the δ‐ and µ‐opioid receptors to explain their different biological activities. The important factors explaining particular ligand activity such as free energy of binding, conformation of the ligand, its location inside the binding pocket as well as the number and strength of the receptor–ligand interactions have been discussed. Several different binding modes for investigated ligands have been proposed. It appears that the binding site is not identical even for very similar ligands. Results of this study help to explain the differences in biological activity of the deltorphin analogues, their interaction with the opioid receptors at the molecular level and support designing a new generation of potent opioid drugs with improved selectivity. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Tanshinone IIa Alleviates the Biochemical Changes Associated with Hypoxic Ischemic Brain Damage in a Rat Model
Authors: Hei Mingyan , Luo Yali , Zhang Xiaochun , Liu Furong
Published: April 2011

This study aimed to investigate the effects of Tanshinone IIa (TanIIa) on the biochemical changes associated with hypoxic ischemic brain damage (HIBD) in a rat model. Neonatal SD rats were randomized into normal control, HIBD and TanIIa + HIBD groups. At different time points after HIBD, TanIIa was given at 1 µg/g. The intracellular free calcium concentration and the expression of phospho‐NR1 S897 was determined. The intracellular free calcium concentration in the HIBD group was significantly increased. The induction of intracellular free calcium concentration in the TanIIa + HIBD group was less than that in the HIBD group. Large amounts of phospho‐NR1 S897 positive cells were distributed in the cortex in the normal control group; the number of phospho‐NR1 S897 positive cells in the ipsilateral cortex was dramatically decreased at 24 h after HIBD. Both the number of phospho‐NR1 S897 positive cells and the FITC fluorescent density in the HIBD + TanIIa group were less than those in the normal control group at every time point after HIBD, but more than those in the HIBD group. TanIIa alleviated the down‐regulation of phospho‐NR1 S897 and the elevated intracellular free calcium concentration in the cerebral cortex in the HIBD model. TanIIa could exert a neuroprotective effect through affecting NMDA receptor expression, inhibiting calcium transportation and decreasing the intracellular free calcium concentration. Copyright © 2011 John Wiley & Sons, Ltd.
When is R2 appropriate for comparing customer and supplier measurement systems?
Authors: Nachtsheim Christopher J. , Becker Kevin E.
Published: April 2011

Linear regression analysis is often used to compare paired supplier and customer measurements of a given quantitative product characteristic in a shipment of products. Specifically, the coefficient of determination, R2, is then used to determine if the supplier's and the buyer's measurement systems are in conformity, with sufficiently high values implying agreement. In this article, we show that R2 istextitnever an appropriate statistic for making this determination. Examples are provided and an appropriate methodology for comparing two measurement systems is delineated. Copyright © 2011 John Wiley & Sons, Ltd.
Active role of hydrogen bond and ambient water in Meyer–Schuster rearrangements in high‐temperature water
Authors: Wang Zhizhong , Chang Yongjuan , Gong Xinxin , Dai Liyi
Published: April 2011

Meyer–Schuster rearrangements of 2‐phenyl‐3‐butyn‐2‐ol with H3O+ and (H2O)6 model in high‐temperature water (HTW) have been investigated by the use of density functional theory calculations. In the substrate 2‐phenyl‐3‐butyn‐2‐ol catalyzed by H3O+ and (H2O)6, the Meyer–Schuster rearrangements were predicted by the frontier molecular orbital theory. The results show that the rearrangement does not involve the carbonium ion intermediates, but the first transition state is carboniumion like. Dehydration and hydration may occur via the intermolecular proton relay along the hydrogen‐bond chains and the second step of reaction path is a total acid–base catalytic process. Based on the results, a model considered both HTW ambient and water molecules are proposed to represent mechanisms of other reactions in HTW. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011