bluuebunny/crossref_metadata_2025 huggingface dataset:
Expansion and characterization of adipose tissue‐derived stromal cells cultured with low serum medium
Authors: Hattori Hidemi , Nogami Yashiro , Tanaka Tomohiro , Amano Yoshiko , Fukuda Koichi , Kishimoto Satoko , Kanatani Yasuhiro , Nakamura Shingo , Takase Bonpei , Ishihara Masayuki
Published: May 2008

Adipose tissue contains a population of cells that have extensive self‐renewal capacity and the ability to differentiate along multiple lineages. In addition, adipose tissue‐derived stromal cells (ATSCs) are able to differentiate into various cell types that may be useful for autologous cell transplantation for defects of bone, cartilage, adipose, and tendon, etc. Most protocols for in vitro cultures of ATSCs include fetal bovine serum (FBS) as a nutritional supplement. However, in some cell cultures, it involves multiple doses of FBS, which raises a concern over possible infections as well as immunological reactions that are caused by medium‐derived FBS proteins, sialic acid, etc. In this study, we were able to expand mouse ATSCs using low mouse serum media containing collagen type I, heparin‐carrying polystyrene, and fibroblast growth factor (FGF)‐2. These expanded mouse ATSCs maintained their multilineage potential for differentiation into adipocytes, osteoblasts, and chondrocytes. Therefore, this method, which uses autologous cells and low serum media, may be able to be utilized for clinical cell therapies. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
IFN‐γ regulation of vacuolar pH, cathepsin D processing and autophagy in mammary epithelial cells
Authors: Khalkhali‐Ellis Zhila , Abbott Daniel E. , Bailey Caleb M. , Goossens William , Margaryan Naira V. , Gluck Stephen L. , Reuveni Moshe , Hendrix Mary J.C.
Published: May 2008

In this study we examined the ability of interferon‐γ (IFN‐γ) to regulate mammary epithelial cell growth and gene expression, with particular emphasis on two genes: Maspin (a member of serine protease inhibitor superfamily), and the lysosomal aspartyl endopeptidase cathepsin D (CatD). The protein products of these genes are critically involved in regulation of multitude of biological functions in different stages of mammary tissue development and remodeling. In addition, the expression of Maspin is down‐regulated in primary breast cancer and is lost in metastatic disease, while CatD is excessively produced and aberrantly secreted by breast cancer cells. We report that IFN‐γ receptors are expressed in mammary epithelial cells, and receptor engagement by IFN‐γ transduces the IFN‐γ signal via Stat‐1 resulting in decreased vacuolar pH. This change in vacuolar pH alters CatD protein processing and secretion concurrent with increased Maspin secretion. In addition, IFN‐γ exerts a suppressive effect on cell growth and proliferation, and induces morphological changes in mammary epithelial cells. Our studies also reveal that breast cancer cells, which are devoid of Maspin, are refractory to IFN‐γ with respect to changes in vacuolar pH and CatD. However, Maspin transfection of breast cancer cells partially sensitizes the cells to IFN‐γ's effect, thus providing new therapeutic implications. J. Cell. Biochem. 105: 208–218, 2008. © 2008 Wiley‐Liss, Inc.
Hydrodynamic modeling of diffusion tensor properties of flexible molecules
Authors: Barone Vincenzo , Zerbetto Mirco , Polimeno Antonino
Published: May 2008

We present a computationally efficient implementation of hydrodynamic modeling for the evaluation of diffusion tensors of molecules with internal degrees of freedom, adapted to take into account information from linear scaling computations of solvent accessible surfaces implemented in the framework of last generation continuum solvent models. Torsional angles are taken also explicitly into account, while retaining correct hydrodynamic interactions. A comparison with literature data is presented to prove the effectiveness of the approach for a wide range of molecular dimensions and solvent environments. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
HIV‐1 protease cleavage site prediction based on amino acid property
Authors: Niu Bing , Lu Lin , Liu Liang , Gu Tian Hong , Feng Kai‐Yan , Lu Wen‐Cong , Cai Yu‐Dong
Published: May 2008

Knowledge of the polyprotein cleavage sites by HIV protease will refine our understanding of its specificity, and the information thus acquired is useful for designing specific and efficient HIV protease inhibitors. Recently, several works have approached the HIV‐1 protease specificity problem by applying a number of classifier creation and combination methods. The pace in searching for the proper inhibitors of HIV protease will be greatly expedited if one can find an accurate, robust, and rapid method for predicting the cleavage sites in proteins by HIV protease. In this article, we selected HIV‐1 protease as the subject of the study. 299 oligopeptides were chosen for the training set, while the other 63 oligopeptides were taken as a test set. The peptides are represented by features constructed by AAIndex (Kawashima et al., Nucleic Acids Res 1999, 27, 368; Kawashima and Kanehisa, Nucleic Acids Res 2000, 28, 374). The mRMR method (Maximum Relevance, Minimum Redundancy; Ding and Peng, Proc Second IEEE Comput Syst Bioinformatics Conf 2003, 523; Peng et al., IEEE Trans Pattern Anal Mach Intell 2005, 27, 1226) combining with incremental feature selection (IFS) and feature forward search (FFS) are applied to find the two important cleavage sites and to select 364 important biochemistry features by jackknife test. Using KNN (K‐nearest neighbors) to combine the selected features, the prediction model obtains high accuracy rate of 91.3% for Jackknife cross‐validation test and 87.3% for independent‐set test. It is expected that our feature selection scheme can be referred to as a useful assistant technique for finding effective inhibitors of HIV protease, especially for the scientists in this field. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009
A conscious‐authentic leadership approach in the workplace: Leading from within
Authors: Hofman Robert E.
Published: May 2008

This study combines components of the relatively nascent concepts of conscious leadership and authentic leadership. It is a synopsis of a recent empirical study comparing two groups of companies and their respective CEOs. Each group is comprised of three companies. Group I is led by CEOs who use a conscious‐authentic leadership approach in the workplace. They infuse their personal values, beliefs, and relational leadership behavior into the policies, practices, and employee programs within their respective organizations to achieve specific organizational outcomes. Group II CEOs do not use this leadership approach. The companies selected for study were categorized by disinterested third parties in the business community. This study explores the perceptions of the employees of both groups and the impact of the conscious‐authentic leadership model on organizational behavior and specific organizational outcomes in the workplace. The organizational outcomes tested in this study are voluntary employee‐withdrawal behavior and absenteeism during the period 2003–2005. An employee questionnaire was administered to the employees of both groups to measure organizational behavior. The same questionnaire was administered to the CEOs to determine their level of self‐awareness and their sense of the reality of the human condition within their respective organization. A separate leadership questionnaire was administered to the CEOs for a self‐assessment of personal attributes and leadership style. The findings provide a working definition of conscious‐authentic leadership behavior and a working model of the components of this approach as implemented by Group I CEOs in the workplace.
Information processing and leadership styles: Constructive thinking and transformational leadership
Authors: Cerni Tom , Curtis Guy J. , Colmar Susan H.
Published: May 2008

Transformational leaders increase job satisfaction and well‐being among workers. According to the cognitive‐experiential self‐theory (CEST), all behavior is guided by two information‐processing systems: a rational and an experiential system. Study 1 examined the relationship between information processing and transformational leadership among experienced school leaders (N= 183). The rational system had a strong positive correlation with transformational leadership, whereas the experiential system was weakly correlated. Study 2 (N= 126) examined constructive thinking and transformational leadership. Global constructive thinking, emotional coping, and behavioral coping all had strong positive correlations with transformational leadership. These results suggest that improving leaders' awareness of their own information‐processing and thinking systems might encourage more productive transformational‐leadership techniques.
Ontogeny of sexual development in the roach (Rutilus rutilus) and its interrelationships with growth and age
Authors: Paull G.C. , Lange A. , Henshaw A.C. , Tyler C.R.
Published: May 2008

The roach (Rutilus rutilus) has become a sentinel species for the study of sexual disruption in wild fish populations as a consequence of exposure to endocrine disrupting chemicals (EDCs). Little is known, however, about the normal ontogeny of sexual development in this species. Here, we analyzed the ontogeny of sexual development in captive‐bred roach and assessed how growth rate and fish size affected the timing of both sexual differentiation and sexual development over a 2‐year period. Ovarian differentiation was first recorded at 68 days post‐fertilization (dpf) and this preceded testicular differentiation (first recorded at 98 dpf). In contrast, sexual maturation occurred at an earlier age in males (300 dpf) compared with females (728 dpf). No differences in body size (length or weight) were recorded between male and female roach until the fish were 415 dpf. Studies on three populations of roach which grew at different rates showed that the timing of sexual differentiation was highly variable and more related to fish size than to fish age. Time to sexual maturation was also variable among populations but, subsequent to their first year of life, gonadal status was less well associated with fish size. Interestingly, the sex ratio of the population was biased towards females in populations that grew more rapidly during early life. The findings presented here provide a valuable foundation of work to support both field‐ and laboratory‐based assessments on the effects of EDCs, and other stressors, on sexual differentiation and development in the roach. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
Online optimization of surface plasmon resonance‐based biosensor experiments for improved throughput and confidence
Authors: De Crescenzo Gregory , Woodward Lyne , Srinivasan Bala
Published: May 2008

The emergence of surface plasmon resonance‐based optical biosensors has facilitated the identification of kinetic parameters for various macromolecular interactions. Normally, these parameters are determined from experiments with arbitrarily chosen periods of macromolecule and buffer injections, and varying macromolecule concentrations. Since the choice of these variables is arbitrary, such experiments may not provide the required confidence in identified kinetic parameters expressed in terms of standard errors. In this work, an iterative optimization approach is used to determine the above‐mentioned variables so as to reduce the experimentation time, while treating the required standard errors as constraints. It is shown using multiple experimental and simulated data that the desired confidence can be reached with much shorter experiments than those generally performed by biosensor users. Copyright © 2008 John Wiley & Sons, Ltd.
Macromol. Mater. Eng. 5/2008
Authors: Rietveld Ivo B. , Suganuma Naotoshi , Kobayashi Kei , Yamada Hirofumi , Matsushige Kazumi
Published: May 2008

Cover: The cover picture represents the assembly of multilayered thin films. Photoresist is deposited with electrospray on a pentacene thin film, which in turn has been deposited on a gold film on top of SiO2. Electrospray deposition is used as a low impact deposition method, which allows construction of patterned layers on fragile thin films. Further details can be found in the article by I. B. Rietveld,* N. Suganuma, K. Kobayashi, H. Yamada, and K. Matsushige on page 387.
Biodegradable Polymer Nanocylinders Fabricated by Transverse Fragmentation of Electrospun Nanofibers through Aminolysis
Authors: Kim Taek Gyoung , Park Tae Gwan
Published: May 2008

Biodegradable polymeric nanocylinders were fabricated by segmental degradation of electrospun nanofibers. Poly(L‐lactic acid) (PLA) was electrospun to produce non‐crystalline nanofibers that were immediately treated with amino group‐containing strong bases to fabricate semi‐crystalline PLA nanocylinders with tunable aspect ratio. The formation of PLA nanocylinders was attributed to two concurrent events occurring during the aminolysis reaction: (i) development of stacked lamellae and (ii) transversely oriented degradation and fragmentation of the amorphous gaps between lamellae, both responsible for the fragmentation of PLA nanofibers into uniformly shaped nanocylinders. The aspect ratio of PLA nanocylinders was tunable by varying aminolysis time and controlling nanofiber diameter.

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Monte Carlo Simulation of Emulsion Polymerization Kinetics and the Evolution of Latex Particle Morphology and Polymer Chain Architecture
Authors: Stubbs Jeffrey , Carrier Robert , Sundberg Donald C.
Published: May 2008

Monte Carlo methods were applied to the reaction kinetics and polymer diffusion at play during the dynamics of creating structured latex particles. Reaction kinetic events in both the water phase and the particles are combined with diffusion of polymer radicals in the particles to allow the prediction of the overall polymerization kinetics, including the Trommsdorf gel effect, chain transfer reactions to monomer, chain transfer agents (e.g., thiols) and polymer chains, and chain length dependent termination reactions. This allowed the calculation of latex particle morphology, as well as the polymer molecular weight, gel content and graft level, when applicable. A number of examples are used to provide experimental data with which to compare the Monte Carlo predictions.

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Self‐Assembly of Cylinder‐Forming ABA Triblock Copolymers under Cylindrical Confinement
Authors: Wang Zheng , Li Baohui , Jin Qinghua , Ding Datong , Shi An‐Chang
Published: May 2008

The self‐assembly of two types of linear ABA triblock copolymers confined in cylindrical nanopores is studied using simulated annealing. The effects of pore size and block copolymer chain architecture on morphology, chain conformations and bridging fraction are investigated. For the bulk cylinder‐forming copolymers, novel structures such as helices and stacked toroids form, which depend sensitively on the pore size. Several significant differences between the two types of copolymers are predicted and explained based on the differences in their chain conformations and chain architectures. A simple model is proposed to explain the mean square radius of gyration for the bridge and loop chains.

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Internal doses of acrylamide and glycidamide in mice fed diets with low acrylamide contents
Authors: Vikström Anna C. , Eriksson Sune , Paulsson Birgit , Karlsson Patrik , Athanassiadis Ioannis , Törnqvist Margareta
Published: May 2008

The formation of acrylamide during heating of certain foodstuffs constitutes a potential health hazard. The health risk assessment should be based on knowledge about the relation between dietary exposure to acrylamide and internal doses of acrylamide and its genotoxic metabolite glycidamide. The primary aim of this study in mice was to measure these relationships at low levels of acrylamide intake through the diet. A secondary aim was to clarify which extraction method should be used when analyzing acrylamide in food in order to obtain a correct measure of the acrylamide that is available for absorption. In the analysis procedure, alkaline extraction has earlier shown much higher measured acrylamide levels in certain foods compared to water extraction. In this subcronic study the administered diets were composed to give five levels of acrylamide intakes between 3 and 50 μg/kg body weight per day (calculated on figures obtained after water extraction). Internal doses of acrylamide and glycidamide were measured through hemoglobin (Hb)‐adducts. The results showed linear relationships between the exposure of acrylamide and Hb‐adduct levels from both acrylamide and glycidamide at these low exposure levels. The study also showed that the “extra” acrylamide measured with alkaline extraction does not correspond to bioavailable acrylamide.
Protective effects of lupeol against benzo[a]pyrene induced clastogenicity in mouse bone marrow cells
Authors: Prasad Sahdeo , Kumar Yadav Vinay , Srivastava Smita , Shukla Yogeshwer
Published: May 2008

Fruits and vegetables contain a variety of ingredients that exhibit chemopreventive effects against an array of xenobiotics. In the present study, the antigenotoxic potential of lupeol, a triterpene, and mango pulp extract (MPE) was evaluated in Swiss albino mice. Benzo[a]pyrene (B[a]P), a well‐known mutagen, was given at a single dose of 100 mg/kg body weight intraperitoneally. Pretreatment with lupeol (1 mg/animal) and MPE (1 mL, 20%) was given through oral intubation for 7 days prior to B[a]P administration. Animals from all the groups were killed at sampling time of 24 h and their bone marrow tissue was analyzed for chromosomal damage and micronuclei induction. In B[a]P‐treated animals a significant induction of chromosomal aberration and micronuclei was recorded, with a decrease in mitotic index. In lupeol‐ or MPE‐supplemented groups, a significant decrease in B[a]P‐induced clastogenicity was recorded. The incidence of aberrant cells and micronuclei was found to be reduced by both lupeol and MPE when compared to the B[a]P‐treated group. The anti‐cytotoxic effects of lupeol or MPE were also evident, as observed by significant increase in mitotic index. Thus, results of the present investigation revealed that lupeol and MPE have protective effects against B[a]P‐induced clastogenic changes in Swiss albino mice.
Epigallocatechin gallate (EGCG) attenuates high glucose‐induced insulin signaling blockade in human hepG2 hepatoma cells
Authors: Lin Chih‐Li , Lin Jen‐Kun
Published: May 2008

Insulin resistance is the primary characteristic of type 2 diabetes which as a result of insulin signaling defects. It has been suggested that the tea polyphenol (–)‐epigallocatechin‐3‐gallate (EGCG) displays some antidiabetic effects, but the mechanism for EGCG insulin‐enhancing effects is incompletely understood. In the present study, the investigations of EGCG on insulin signaling are performed in insulin‐responsive human HepG2 cells cotreated with high glucose. We found that the high glucose condition causes significant increasing Ser307 phosphorylation of insulin receptor substrate‐1 (IRS‐1), leading to reduce insulin‐stimulated phosphorylation of Akt. As the results, the insulin metabolic effects of glycogen synthesis and glucose uptake are inhibited by high glucose. However, the treatment of EGCG improves insulin‐stimulated downsignaling by reducing IRS‐1 Ser307 phosphorylation. Furthermore, we also demonstrated these EGCG effects are essential depends on the 5′‐AMP‐activated protein kinase (AMPK) activation. Together, our data suggest a putative link between high glucose and insulin resistance in HepG2 cells, and the EGCG treatment attenuates insulin signaling blockade by reducing IRS‐1 Ser307 phosphorylation through the AMPK activation pathway.
Modification of porous PVC particles with PS and P(St‐co‐MMA) using a surfactant‐free aqueous dispersion polymerization technique
Authors: Hammer S. , Tchoudakov R. , Mechrez G. , Cohen Y. , Narkis M.
Published: May 2008

The modification of suspension‐type porous polyvinyl chloride (PVC) particles by an in situ stabilizer‐free polymerization/crosslinking of a monomer solution absorbed within the PVC particles is presented. The modifying polymers are polystyrene (PS) and poly(styrene‐co‐methyl methacrylate) (P(St‐co‐MMA)) crosslinked with divinyl benzene (DVB). The effect of the unique blending procedure on the physical and mechanical properties of PVC has been investigated. The modified PVC characterization includes polymerization yield, transparency, fracture surface morphology, thermal stability, dynamic mechanical properties, tensile properties, and impact resistance. The polymer chains formed are dispersed as a separate phase observed by scanning electron microscopy (SEM), typical of immiscible polymer blends. Various morphologies induced by injection molding were observed including ellipsoid, bead‐and‐string, and thin threads morphologies, which depend on the characteristics of the components as well as the processing conditions. Thermal stability was generally increased by the incorporation of PS or P(St‐co‐MMA) in PVC. Mechanical properties of PVC/P(St‐co‐MMA) blend reveal a substantial increase in elongation at break; PVC/PS blends, however, exhibit a brittle failure. Rigidity and tensile strength of the PVC‐based blends were maintained. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of the surface modification of alumina nanoparticles on the thermal stability and fire reaction of PMMA composites
Authors: Cinausero Nicolas , Azema Nathalie , Cochez Marianne , Ferriol Michel , Essahli Mohamed , Ganachaud François , Lopez‐Cuesta José‐Marie
Published: May 2008

Nanometric aluminum oxide particles were modified by phosphonic acid‐based oligomers of aromatic polyester, polyether, or polydimethylsiloxane (PDMS). The grafting process was characterized by FTIR spectroscopy and thermogravimetric analysis (TGA) showing that covalent bonds must have formed between the oxide and oligomers. The highest yield of grafting was achieved in dichloromethane (CH2Cl2) solvent. Then, nanocomposites were prepared by melt‐blending in a poly(methyl methacrylate) (PMMA) matrix. The best results in terms of thermal stability and flammability were obtained with the bis‐phosphonicpolydimethylsiloxane‐based formulation. With this latter, the peak of heat released rate (pHRR) decreased during the combustion, whereas PyGC/MS experiments led to the conclusion that PDMS‐covered nanoparticles played a role in the composition of the gaseous phase as well. Copyright © 2008 John Wiley & Sons, Ltd.
A novel intumescent flame‐retardant LDPE system and its thermo‐oxidative degradation and flame‐retardant mechanisms
Authors: Liu Yun , Wang De‐Yi , Wang Jun‐Sheng , Song Yan‐Peng , Wang Yu‐Zhong
Published: May 2008

A carbonization agent, 3,9‐di (2‐hydroxyisopropyl)‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro‐[5,5]‐undecane (SPEPO), was synthesized from pentaerythritol (PER), phosphorus trichloride, formic acid, and acetone as raw materials. The structure of SPEPO was characterized by FTIR and 1H‐NMR. As a carbonization agent and an acid source, SPEPO can form a novel intumescent flame‐retardant (IFR) system for low density polyethylene (LDPE) together with ammonium polyphosphate (APP) and melamine phosphate (MP). The flame retardancy and thermal behavior of the IFR system for LDPE were investigated by limiting oxygen index (LOI), UL‐94 test, and thermogravimetric analysis (TGA). When the weight ratio of SPEPO, APP, and MP is 7:7:1 and their total loading level is 30%, the IFR‐LDPE presents the optimal flame retardancy (LOI value of 27.6 and UL‐94 V‐0 rating). However, SPEPO, APP, or MP can only show a very poor flame‐retardant performance when used alone. This indicates that there is a synergistic effect among SPEPO, APP, and MP. TGA results obtained in air demonstrate that SPEPO has an ability of char formation itself, and the char residue of SPEPO can reach 24 wt% at 700°C. The IFR can change the thermal degradation behavior of LDPE, enhance Tmax of the decomposition peak of LDPE, and promote LDPE to form char based on the calculated and the experimental data of residues. According to the results of Py‐GC/MS in combination with FTIR of the char residues at different temperatures, a possible flame‐retardant mechanism has been proposed. Copyright © 2008 John Wiley & Sons, Ltd.
Failure analysis of fiber‐reinforced composites under multiaxial cyclic stress
Authors: Qi Dongtao , Cheng Guangxu
Published: May 2008

A preliminary study on the fatigue failure of continuous fiber reinforced composites under multiaxial stress has been presented. A model used to predict the direction of the critical plane of composite laminae under multiaxial cyclic stress is developed. First, two types of planes in the unidirectional lamina are defined in order to discriminate the different failure mechanisms, i.e. fibre failure and inter‐fibre failure. Based on planes of different types, the concept of effective stress is proposed to determine the direction of the critical plane. Second, fatigue experiments of filament wound composites under biaxial loading are carried out and the failure planes are described. Results show that the fracture planes in reality are close to the critical planes predicted by the model. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Impact strength of recycled thermoplastic composites subjected to corrosive environment
Authors: Papanicolaou G.C. , Karagiannis D. , Bofilios D.A. , van Lochem J.H. , Henriksen C. , Lund H.H.
Published: May 2008

The objective of the present study is to investigate the effect of hygrothermal aging on the impact strength of virgin and recycled commercial polyphenylenesulfide (PPS) matrix composites reinforced with 40% by weight of short glass fibres after water absorption at different pH and temperature environments. This study is part of a long‐term strategy for developing a sound methodology for reusing short fiber‐reinforced thermoplastic materials. Hygrothermal aging has been conducted so as to represent actual service conditions identified for the components made from these recycled materials. Taking into account the corrosive nature of the service environment in which the aforementioned components are required to operate, a study of the recycled material impact strength as a function of the environmental conditions to which they are subjected, is deemed indispensable before using them for the manufacturing of new products. The results of the present study showed a great effect of the various parameters studied such as, water temperature, alkaline or acidic nature of the environment, andtype of the coupling agent used on the impact behavior of the PPS‐glass fiber composites investigated. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Transmission of ultraviolet light through reinforcement fabrics and its effect on ultraviolet curing of composite laminates
Authors: Endruweit Andreas , Ruijter Wout , Johnson Michael S. , Long Andrew C.
Published: May 2008

The ultraviolet transmission of various reinforcement textiles was quantified experimentally for the case of incidence of light normal on the fabric plane, and correlated with the curing behavior of laminates incorporating these fabrics. For glass fiber fabrics wetted with polyester resin, light is transmitted through the voids between the fiber bundles and through the fiber bundles. Multiscale modeling of the fabric geometry allows the local transmission to be estimated and the average total transmission to be quantified. The results of curing experiments suggest that the degree of through‐cure achieved after a given cure time is correlated to the fabric transmission. Both are determined by the laminate thickness, the fabric architecture and the fiber volume fraction, i.e., the fiber packing density. While the transmission is reduced by the presence of the reinforcement fabrics, the total resin volume is reduced when compared with that of a resin only sample of the same thickness. A lower radiation dose is sufficient for curing, which partially compensates for the effect of reduced transmission. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
High velocity impact behavior of GRP panels containing coarse‐sized sand filler
Authors: Sabet A.R. , Beheshty M.H. , Rahimi H.
Published: May 2008

Ballistic performance of glass reinforced plastic (GRP) composite plates containing coarse sized sand filler was investigated as an attempt towards developing a low cost armored system. In all, 10 different types of plates from 4 to 12 layers of E‐glass chopped strand mat reinforced polyester resin containing 0, 10, and 20% of 600‐ to 700‐μm sized sand filler were tested. A smooth barrel gas gun was used to conduct high velocity tests in the range of 70–185 m/s. Results indicated higher ballistic performance for GRP plates with sand filler in terms of higher ballistic limits (velocity at which at least 50% of samples were partially or fully penetrated the target plates with zero residual velocity), particularly for plates with highest sand filler loadings. Energy absorption associated with these specimens also showed higher performance. Delamination was identified as dominant failure mode, in particular for thicker specimens with highest sand filler loading. Specific energy absorption per weight per unit area for the composite plates indicated diminishing effectiveness with increase in sand filler loading, thereby limiting its possible application to armored system for stationary objects only. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Preparation and properties of novel natural rubber/organo‐vermiculite nanocomposites
Authors: Zhang Yao , Liu Wei , Han Wei , Guo Weihong , Wu Chifei
Published: May 2008

Polymer‐layered silicate nanocomposites have an attracting increasing attention over recent years because of their unique mechanical, thermal, and other properties. In this article, a new kind of natural rubber (NR)/organo‐vermiculite (OVMT) nanocomposites were investigated. The vermiculite (VMT) was intercalated by cetyltrimethylammonium bromide with ball mill method. The intercalation led to an increase of the d(001) of VMT from 1.46 nm to 4.51 nm. NR/OVMT nanocomposites were prepared via a melt process in a HAAKE mixer and were analyzed by X‐ray diffraction and scanning electron microscope observations. The mechanical properties of the vulcanized nanocomposites were tested. It was found that the tensile strength and the elongation at the breaking point of the NR/OVMT nanocomposites loading 15 phr of the OVMT reached 28.4 MPa and 623.2%, respectively. The 300% modulus, tear strength, and hardness (Shore A) of the nanocomposites increased with the increase of the OVMT loading. The thermal properties of the nanocomposites were investigated by dynamic mechanical analysis, and the results showed that the storage modulus and the glass transition temperature of the nanocomposites were increased. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Synthesis and characterization of chlorinated soy oil based epoxy resin/glass fiber composites
Authors: Thulasiraman V. , Rakesh S. , Sarojadevi M.
Published: May 2008

Composites with good toughness properties were prepared from chemically modified soy epoxy resin and glass fiber without additional petroleum based toughening agent. Chlorinated soy epoxy (CSE) resin was prepared from soybean oil. The CSE was characterised by spectral, and titration method. The prepared CSE was blended with commercial epoxy resin in different ratios and cured at 85°C for 3 h, and post cured at 225°C for 2 h using m‐phenylene diamine (MPDA) as curing agent. The cure temperatures of epoxy/CSE/MPDA with different compositions were found to be in the range of (151.2–187.5°C). The composite laminates were fabricated using epoxy /CSE/MPDA‐glass fiber at different compositions. The mechanical properties such as tensile strength (248–299 MPa), tensile modulus (2.4–3.4 GPa), flexural strength (346–379 MPa), flexural modulus (6.3–7.8 GPa) and impact strength (29.7–34.2) were determined. The impact strength increased with the increase in the CSE content. The interlaminor fracture toughness (GIC) values also increased from 0.6953 KJ/m2 for neat epoxy resin to 0.9514 KJ/m2 for 15%CSE epoxy‐modified system. Thermogravimetric studies reveal that the thermal stability of the neat epoxy resin was decreased by incorporation of CSE. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Polyaniline–organoclay nanocomposites as curing agent for epoxy: Preparation and characterization
Authors: Ayad M.M. , Salahuddin N. , Ali M.
Published: May 2008

Polyaniline (PANI)–organoclay/Epoxy (EP) nanocomposites were prepared. PANI–organoclay nanocomposites were used as curing agent for EP. Organoclay was prepared by an ion exchange process between sodium cations in MMT and NH3+ groups in polyoxypropylene (D230). PANI–organoclay nanocomposite was synthesized by in situ polymerization of aniline in (14 wt%) organoclay. Infrared spectra and differential scanning calorimetry confirm the curing of EP. The absence of d001 diffraction band of organoclay in the nanocomposites was observed by X‐ray diffraction. The structure argument was further supported by scanning electron microscopy and transmission electron microscopy. Electrical conductivity of the nanocomposites within the range 2.1 × 10−7–3.2 × 10−7 S/cm depending on the concentration of the PANI/D230‐MMT. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Sandwich structures with composite inserts: Experimental studies
Authors: Naik N.K. , Rao G. Nageswara , Agarwal Ullas , Raju K.A. , Pottigar Shrinivas A. , Suresh V.
Published: May 2008

Experimental studies are presented on the performance of insert assemblies of the sandwich structures under localized through‐the‐thickness compressive loading. Through‐the‐thickness and partially inserted fully potted inserts are studied. Insert materials considered are: aluminum and 3D woven composite. Experimental results are compared with the analytical predictions. It is observed that the specific strength of 3D woven composite inserts is more than that of aluminum inserts. Further, it is observed that the specific strength of through‐the‐thickness inserts is more than that of partially inserted fully potted inserts. Delamination between upper face plate and core material and sliding of attachment/insert within the core are the main modes of failure initiation. Quantitative results are presented for typical cases. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Do general nucleophilicity scales exist?
Authors: Mayr Herbert , Ofial Armin R.
Published: May 2008

Comprehensive nucleophilicity scales including π‐, n‐ and σ‐nucleophiles have been constructed using benzhydrylium ions and structurally related quinone methides as reference electrophiles. It is shown how the correlation (Eqn (1)) log k20°C = s(E + N), where s and N are nucleophile‐specific parameters and E is an electrophile‐specific parameter, has recently been employed to characterize further classes of nucleophiles (phosphines, amines, isonitriles, trifluoromethanesulfonyl‐substituted carbanions) and electrophiles (2‐benzylideneindan‐1,3‐diones and benzylidenebarbituric acids). Practical applications of the reactivity parameters E, N and s for developing Friedel–Crafts alkylations in neutral alcoholic or aqueous solution and for characterizing nucleophilic organocatalysts will be discussed. Eventually, a new correlation equation will be presented, which includes Eqn (1), the Ritchie equation (nucleophilic additions to stabilized carbocations), and the Swain–Scott equation (nucleophilic substitutions of methyl halides) as special cases. Copyright © 2008 John Wiley & Sons, Ltd.
A chemical understanding for the enhanced hydrogen tunnelling in hydroperoxidation of linoleic acid catalysed by soybean lipoxygenase‐1
Authors: Barroso Monica , Arnaut Luis G. , Formosinho Sebastião J.
Published: May 2008

The reaction path of the Interacting‐State Model (ISM) is used with the Transition‐State Theory (TST) and the semiclassical correction for tunnelling (ISM/scTST) to calculate the rates of H‐atom abstraction from C(11) of linoleic acid catalysed by soybean lipoxygenase‐1 (SLO), as well as of an analogous uncatalysed reaction in solution. The calculated hydrogen‐atom transfer rates, their temperature dependency and kinetic isotope effect (KIE) are in good agreement with the experimental data. ISM/scTST calculations reveal the hypersensitivity of the rate to protein dynamics when the hydrogen bonding to a carbon atom is present in the reaction coordinate. Copyright © 2008 John Wiley & Sons, Ltd.
Oriented crystallization of poly(L‐lactic acid) in uniaxially oriented blends with poly(vinylidene fluoride)
Authors: Kaito Akira , Iwakura Yuko , Li Yongjin , Shimizu Hiroshi
Published: May 2008

This article describes the oriented crystallization of poly(L‐lactic acid) (PLLA) in uniaxially oriented blends with poly(vinylidene fluoride) (PVDF). Uniaxially drawn films of PLLA/PVDF blend with fixed ends were heat‐treated in two ways to crystallize PLLA in oriented blend films. The crystal orientation of PLLA depended upon the heat‐treatment process. The crystal c‐axis of the α form crystal of PLLA was highly oriented in the drawing direction in a sample cold‐crystallized at Tc = 120 °C, whereas the tilt‐orientation of the [200]/ [110] axes of PLLA was induced in the sample crystallized at Tc = 120 °C after preheating at Tp = 164.5–168.5 °C. Detailed analysis of the wide‐angle X‐ray diffraction (WAXD) indicated that the [020]/ [310] crystal axes were oriented parallel to the drawing direction, which causes the tilt‐orientation of the [200]/ [110] axes and other crystal axes. Scanning electron microscopy (SEM) suggested that oriented crystallization occurs in the stretched domains of PLLA with diameters of 0.5–2.0 μm in the uniaxially drawn films of PVDF/PLLA = 90/10 blend. Although the mechanism for the oriented crystallization of PLLA was not clear, a possibility was heteroepitaxy of the [200]/[110] axes of the α form crystal of PLLA along the [201]/[111] axes of the β form crystal of PVDF that is induced by lattice matching of d100(PLLA) ≈ 5d201(PVDF). © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1376–1389, 2008
Medication at discharge: is enough information provided?
Authors: Wilcock Michael , Lawrence Joanna
Published: May 2008

Hospitalisation frequently results in changes to the patient's medication. The authors describe the results of an audit to assess the accuracy of discharge information provided to GPs regarding medication changes. Copyright © 2008 Wiley Interface Ltd
Effects of surface states on hydrogen sensing performance of Pt‐GaN Schottky diodes
Authors: Irokawa Y. , Sakuma Y. , Sekiguchi T.
Published: May 2008

Effects of surface states on hydrogen sensing performance of Pt‐GaN Schottky diodes were investigated. First, hydrogen sensing characteristics of Pt‐GaN Schottky diodes fabricated on as‐grown and annealed GaN surfaces are studied in order to investigate the correlation between the surface defects of GaN and hydrogen sensing performance. As a result, significant differences of the sensitivity among the devices were not observed, indicating that surface defects of GaN do not play a critical role in hydrogen sensing characteristics of Pt‐GaN Schottky diodes. Second, influence of dielectrics between Pt and GaN surface was studied. In consequence, Pt‐GaN diodes with 10nm SiO2 dielectric between Pt and GaN surface, deposited by RF sputtering, show the dramatic improvement of the hydrogen detection sensitivity, which is twice higher than for conventional Pt‐GaN Schottky diodes. By sharp contrast, Pt‐GaN diodes with 10nm SixNy dielectric, deposited by RF sputtering, do not show any response to hydrogen. These results suggest that dielectrics between metal and semiconductor are much more important than surface defects in hydrogen sensing performance. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal precipitation of self‐organized PbTe quantum dots in CdTe host matrix
Authors: Koike K. , Itakura T. , Hotei T. , Yano M. , Groiss H. , Hesser G. , Schäffler F.
Published: May 2008

This paper describes a selective growth of PbTe/CdTe quantum wells (QWs) and quantum dots (QDs) in CdTe host matrix by molecular beam epitaxy. These two tellurides possess almost identical lattice constants, but differ fundamentally in their lattice structure. Owing to a strong phase separation by the lattice‐type mismatch, insertion of a PbTe thin layer in CdTe matrix at higher temperatures than 280 °C was resulted in a self‐organized growth of coherent and three‐dimensionally isotropic QDs. The same growth procedure at lower temperatures, on the other hand, yielded a conventional QW structure with sharp heterointerface. This QW structure, however, was found to precipitate well‐ordered QD‐array by a postgrowth annealing, indicating that the QD formation is induced by the minimization of interface energy between the inmiscible two tellurides. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heteroepitaxial InSb films grown via Si(111)‐√7×√3‐In surface reconstruction
Authors: Mori M. , Saito M. , Nagashima K. , Ueda K. , Yamashita Y. , Tatsuyama C. , Tambo T. , Maezawa K.
Published: May 2008

The In‐Sb bi‐layer (Si(111)‐2×2‐InSb surface reconstruction) was able to be prepared by 1 monolayer Sb adsorption onto Si(111)‐√7×√3‐In surface reconstruction, as well as results with 2×2‐In and √3×√3‐In. By using the √7×√3‐In surface reconstruction with higher In coverage, the area covered in the In‐Sb bi‐layer increased, and the area covered by 2×1‐Sb surface phase which caused by desorption of In atoms from In‐Sb bi‐layer decreased. The heteroepitaxial growth of InSb films on a Si(111)substrate via the In‐Sb bi‐layer was carried out by using two‐step growth procedure. The grown InSb films rotated by 30° with respect to Si substrate. Due to the decrease of the area covered by the 2×1‐Sb surface phase, the InSb crystals without rotation, which has poor crystal quality and electric properties, disappeared. Consequently, the electric properties of the films improved than those of the sample grown via 2×2‐In. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlGaN/GaN/InGaN/GaN DH‐HEMTs structure with an AlN interlayer grown by MOCVD
Authors: Tang Jian , Wang Xiaoliang , Xiao Hongling , Ran Junxue , Wang Cuimei , Wang Xiaoyan , Hu Guoxin , Li Jinmin
Published: May 2008

A novel AlGaN/GaN/InGaN/GaN double heterojunction high electron mobility transistors (DH‐HEMTs) structure with an AlN interlayer on sapphire substrate has been grown by MOCVD. The structure featuered a 6‐10 nm In0.1Ga0.9N layer inserted between the GaN channel and GaN buffer. And we also inserted one ultrathin AlN interlayer into the AlGaN/GaN interface, which significantly enhanced the mobility of two‐dimensional electron gas (2DEG) existed in the GaN channel. AFM result of this structure shows a good surface morphology and a low dislocation density, with the root‐mean‐square roughness (RMS) of 0.196 nm for a scan area of 5 μm× 5 μm. Temperature dependent Hall measurement was performed on this sample, and a mobility as high as 1950 cm2/Vs at room temperature (RT) was obtained. The sheet carrier density was 9.89×1012cm–2, and average sheet resistance of 327 Ω/sq was achieved. The mobility obtained in this paper is about 50% higher than other results of similar structures which have been reported. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The electronic structure of Ga‐vacancy in Mn‐doped GaN
Authors: Kang J. , Chang K. J.
Published: May 2008

Using first‐principles theoretical calculations, we find that Ga‐vacancies (VGa) strongly interact with the Mn ions in GaN and thereby significantly affect the electronic and magnetic properties. When Ga‐vacancies are present in the neighbourhood of the Mn ions, a charge transfer occurs from the Mn d band to the acceptor level of VGa. Due to the depopulation of the Mn d band, the Fermi level is generally lowered, and ferromagnetic exchange interactions between the Mn ions are weakened, reducing the Curie temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Helicon‐wave‐excited plasma sputtering deposition of CuAlO2 thin films
Authors: Takahata Satoru , Imao Takashi , Nakanishi Hisayuki , Sugiyama Mutsumi , Chichibu Shigefusa F.
Published: May 2008

Helicon‐wave‐excited plasma sputtering (HWPS) method was used to deposit CuAlO2 films on (0001) Al2O3 substrates at 700–800 °C for the first time. For the films deposited at 700 °C, the best full‐width at half‐maximum (FWHM) value of the (006) CuAlO2 X‐ray diffraction peak was 0.19 degrees, which was smaller than those reported previously using other deposition methods. The HWPS method was shown to have technical importance in developing p ‐type TCO films, as it seldom damage the film surface. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of ZnO:Ga thin films by helicon‐wave‐excited plasma sputtering
Authors: Masaki Shingo , Nakanishi Hisayuki , Sugiyama Mutsumi , Chichibu Shigefusa F.
Published: May 2008

Gallium doped zinc oxide (ZnO:Ga) transparent conducting oxide (TCO) films were prepared by the helicon‐wave‐excited plasma sputtering (HWPS) method. The films deposited at higher than 150 °C showed a preferential {0001}‐oriented growth. A high optical transmittance greater than 80% was obtained in the wavelength range between 400 and 1600 nm, because the HWPS method essentially does not damage the surface of the films. The results indicate that ZnO:Ga films deposited by the HWPS method can be used as a TCO film. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐Study: An Effective Method for Bioterrorism Training in the OR
Authors: Thomas Janet (Janie) Roberta
Published: May 2008

DURING A BIOTERRORIST ATTACK, health care professionals must be prepared to respond appropriately, but many perioperative nurses do not receive adequate education about bioterrorism.

ONE PERIOPERATIVE NURSE led a survey project to determine how prepared perioperative nurses were to respond during a bioterrorist attack and whether a self‐study module would help increase participants' self‐rated levels of preparedness.

THE RESULTS SHOWED that perioperative nurses generally felt unprepared to respond to a bioterrorist event. After reading the self‐study module, nurses from facilities that both did and did not provide education on bioterrorism reported increases in self‐rated levels of preparedness. AORN J 87 (May 2008) 915–924. © AORN, Inc, 2008.
Evaluation of the Antimicrobial Properties of an Alcohol‐free 2% Chlorhexidine Gluconate Solution
Authors: DeBaun Barbara
Published: May 2008

SURGICAL SITE INFECTIONS (SSIs) contribute to morbidity and mortality and increase the costs of patient care. Effective skin decontamination is recommended to reduce the risk of SSI and the transmission of antibiotic‐resistant pathogens.

A MACRODILUTION BROTH METHOD and an in vitro time‐kill method were used to determine the antimicrobial properties of an alcohol‐free 2% chlorhexidine gluconate (CHG) solution against seven bacterial strains, including clinically derived strains of Acinetobacter baumannii and methicillin‐resistant Staphylococcus aureus (MRSA).

THE CHG SOLUTION REDUCED bacterial counts of drug‐resistant Acinetobacter baumannii and community‐associated MRSA by 99.9% within three minutes of exposure, and effectiveness was maintained with significant dilutions of the CHG solution. AORN J 87 (May 2008) 925–933. © AORN, Inc, 2008.
Surgical Treatment of Charcot Neuroarthropathy
Authors: Zgonis Thomas , Stapleton John J. , Jeffries Luke C. , Girard‐Powell Valerie A. , Foster Lynanne J.
Published: May 2008

CHARCOT NEUROARTHROPATHY, a chronic progressive destruction of joint integrity, is believed to result from a disturbance in pain and proprioceptive sensation. It is most commonly treated in patients with uncontrolled diabetes mellitus and dense peripheral neuropathy.

PREVENTION, EARLY DIAGNOSIS, and early treatment are key to a patient's successful outcome. Educating the patient is paramount to avoid further complications and subsequent amputations.

THIS ARTICLE DESCRIBES the pathophysiology, staging, surgical treatment, and natural course of Charcot neuroarthropathy. AORN J 87 (May 2008) 971‐986. © AORN, Inc, 2008.