bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of SDS on human hair: Study on the molecular structure and morphology
Authors: Singh Bhawana , Umapathy Siva
Published: September 2010

This paper presents a model study to understand the effect of surfactants on the physicochemical properties of human hair. FT‐IR ATR spectroscopy has been employed to understand the chemical changes induced by sodium dodecyl sulfate (SDS) on human scalp hair. In particular, the SDS induced changes in the secondary structure of protein present in the outer protective layer of hair, i.e. cuticle, have been investigated. Conformational changes in the secondary structure of protein were studied by curve fitting of the amide I band after every phase of SDS treatment. It has been found that SDS brings rearrangements in the protein backbone conformations by transformingβ‐sheet structure to random coil andβ‐turn. Additionally, AFM and SEM studies were carried out to understand the morphological changes induced on the hair surface. SEM and AFM images demonstrated the rupture and partial erosion of cuticle sublayers. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Trends in Incidence of Subtrochanteric Fragility Fractures and Bisphosphonate Use Among the US Elderly, 1996–2007
Authors: Wang Zhong , Bhattacharyya Timothy
Published: September 2010

Increasing numbers of atypical hip fractures have been reported among patients with bisphosphonate use. However, the nature and extent of the problem are unknown despite recent investigations. To analyze national trends in hip fractures and medication use in the elderly US population, we respectively used the Nationwide Inpatient Sample (NIS) and the Medical Expenditure Panel Survey (MEPS) from 1996 to 2007. In NIS, subtrochanteric fragility fractures were compared with typical hip fractures in femoral neck and intertrochanteric regions. Between 1996 and 2007, age-adjusted rates for typical hip fractures decreased by 31.6% among women (from 1020.5 to 697.4 per 100,000 population) and 20.5% among men (from 424.9 to 337.6 per 100,000 population). In contrast, overall trends in age-adjusted rates for subtrochanteric fragility fractures remained unchanged among men (p = .34) but increased 20.4% among women from 28.4 (95% confidence interval [CI] 27.7–29.1) in 1999 to 34.2 (95% CI 33.4–34.9) per 100,000 population in 2007. The annual percentage increase was 2.1% (95% CI 1.3–2.8, p < .001) based on joinpoint regression analysis. In MEPS, bisphosphonate use increased predominantly in women (from 3.5% in 1996 to 16.6% in 2007) compared with men (2.3% in 2007). In the context of declining typical hip fractures among the US elderly, we observed small but significant increases in the incidence of subtrochanteric fragility fractures from 1999 among postmenopausal women. Using age-adjusted rates, we estimated that for every 100 or so reduction in typical femoral neck or intertrochanteric fractures, there was an increase of one subtrochanteric fragility fracture. © 2011 American Society for Bone and Mineral Research.
Maslinic acid suppresses osteoclastogenesis and prevents ovariectomy-induced bone loss by regulating RANKL-mediated NF-κB and MAPK signaling pathways
Authors: Li Chenghai , Yang Zhengfeng , Li Zhenxi , Ma Yu , Zhang Lipeng , Zheng Chunbing , Qiu Wenwei , Wu Xian , Wang Xiu , Li Hui , Tang Jie , Qian Min , Li Dali , Wang Ping , Luo Jian , Liu Mingyao
Published: September 2010

Activation of NF-κB and MAPK/activator protein 1 (AP-1) signaling pathways by receptor activator NF-κB ligand (RANKL) is essential for osteoclast activity. Targeting NF-κB and MAPK/AP-1 signaling to modulate osteoclast activity has been a promising strategy for osteoclast-related diseases. In this study we examined the effects of maslinic acid (MA), a pentacyclic triterpene acid that is widely present in dietary plants, on RANKL-induced osteoclastogenesis, osteoclast function, and signaling pathways by in vitro and in vivo assay systems. In mouse bone marrow monocytes (BMMs) and RAW264.7 cells, MA inhibited RANKL-induced osteoclastogenesis in a dose-dependent manner within nongrowth inhibitory concentration, and MA decreased osteoclastogenesis-related marker gene expression, including TRACP, MMP9, c-Src, CTR, and cathepsin K. Specifically, MA suppressed osteoclastogenesis and actin ring formation at early stage. In ovariectomized mice, administration of MA prevented ovariectomy-induced bone loss by inhibiting osteoclast activity. At molecular levels, MA abrogated the phosphorylation of MAPKs and AP-1 activity, inhibited the IκBα phosphorylation and degradation, blocked NF-κB/p65 phosphorylation, nuclear translocation, and DNA-binding activity by downregulating RANK expression and blocking RANK interaction with TRAF6. Together our data demonstrate that MA suppresses RANKL-induced osteoclastogenesis through NF-κB and MAPK/AP-1 signaling pathways and that MA is a promising agent in the treatment of osteoclast-related diseases such as osteoporosis. © 2011 American Society for Bone and Mineral Research.
Eco‐friendly and facile one‐pot multicomponent synthesis of acridinediones in water under microwave
Authors: Singh Satish Kumar , Singh Krishna Nand
Published: September 2010

A rapid, improved, and environmentally benign synthesis of 4‐arylacridinediones is reported via one‐pot multicomponent reaction of aromatic aldehydes, dimedone, and ammonium acetate in water without any catalyst under microwave irradiation. Excellent yields, shortest reaction time, and easy work‐up are attractive features of this green protocol. J. Heterocyclic Chem., 2011..
Simultaneous HPLC‐DAD‐MS (ESI+) determination of structural and geometrical isomers of carotenoids in mature grapes
Authors: Crupi Pasquale , Milella Rosa Anna , Antonacci Donato
Published: September 2010

Carotenoids are uniquely functional polyene pigments ubiquitous in nature; aside from being responsible for the color of a wide variety of vegetables, interest is being focused on food carotenoids due to their likely health benefits. From analytical point of view, it is important to unequivocally identify individual carotenoid compounds in many food stuffs. Therefore, isolation of standards from natural sources must be encouraged for accurate identifications. Like many fruits, mature grape berries contain numerous carotenoid compounds, mostly found in the skin at levels two to three times higher than in the pulp. Carotenoid compounds in a typical wine grape variety (Negroamaro) grown in Apulian region were investigated by reversed‐phase C30 (RP‐30) HPLC‐DAD‐MS (ESI+) analysis. As a consequence of an unusual ionization process of carotenoids, their mass spectra registered in the positive ion mode comprised both protonated molecules and molecular ion radicals with little fragmentation. Additionally, selective collision‐induced dissociation (CID) experiments, together with fine structures of the UV–vis spectra, were used to differentiate structural and geometrical isomers. This technique allowed the simultaneous determination of regio‐ and cis‐isomers of lutein (zeaxanthin, 9Z and 9′Z‐lutein) and a cis‐isomer of β‐carotene (9Z‐ β‐carotene), 5,6‐epoxy xanthophylls (violaxanthin, (9′Z)‐neoxanthin, lutein‐5,6‐epoxide) and 5,8‐epoxy xanthophylls diasteroisomers (neochrome, auroxanthin, luteoxanthin, flavoxanthin, chrysanthemaxanthin). Copyright © 2010 John Wiley & Sons, Ltd.
Trace detection of the chlorohydrins of epoxidized soybean oil in foodstuffs by UPLC–ESI–MS/MS
Authors: Suman Michele , De Dominicis Emiliano , Commissati Italo
Published: September 2010

Epoxidized soybean oil (ESBO) is used as an authorized plasticizer and a stabilizer for plastic polymers such as poly(vinyl chloride) (PVC). Recently, however, there has been a concrete effort devoted to its substitution for other plasticizers such as polyadipates. ESBO is exploited particularly in food closure gaskets for metal lids used to seal glass jars and bottles. The closure gaskets form an airtight seal necessary to prevent microbiological contamination. Thus, there are potential uses for food sterilization and storage. Additionally, the main pathway of PVC degradation involves the elimination of HCl, which can react with the epoxy groups of ESBO to give mono‐, polychlorohydrins and/or other cyclic derivatives. The European Food Safety Authority noted that not enough analytical and toxicological data exist to express a formal opinion on the significance for the health effects of such derivatives. At present in the scientific literature, there are only a few indicative results of direct measurements of ESBO derivatives and there are no official analytical methods available for the determination of chlorohydrins directly from foodstuffs. This study presents the first example of the analysis of commercial food sauces for the detection of ESBO‐chlorohydrins (as methyl esters). The results are obtained by a dedicated development of an ultraperformance liquid chromatography–electrospray ionization–tandem mass spectrometry (UPLC–ESI–MS/MS) method. Sample preparation was based on the following main steps: organic extraction, transesterification and solid‐phase extraction clean up. In particular, four isomers for 18‐E‐OHCl chlorohydrin and eight isomers for 18‐2OHCl chlorohydrin were separated and identified. Different food sauces samples closed in glass jars with twist‐off caps were subjected to qualitative determination, which yielded positive results for 18‐E‐OHCl, whereas no traces of 18‐2OHCl were found. Copyright © 2010 John Wiley & Sons, Ltd.
Sorafenib induces growth inhibition and apoptosis of human chondrosarcoma cells by blocking the RAF/ERK/MEK pathway
Authors: Lu Xinchang , Tang Xiaodong , Guo Wei , Ren Tingting , Zhao Hui
Published: September 2010

Background

Chondrosarcoma represents the second most common primary malignant bone tumor causing significant morbidity due to local recurrence and limited treatment options. Conventional cytotoxic chemotherapy has been proven to be largely ineffective to this sarcoma. Here we report that sorafenib is effective in growth inhibition of chondrosarcoma cell lines in vitro.

Methods

Chondrosarcoma cell lines (SW1353 and CRL7891) were treated with sorafenib. Flow cytometry, DAPI assay, and Western blotting were employed to determine the effects of sorafenib in inhibitory proliferation and induce apoptosis in chondrosarcoma cells in vitro.

Results

The results showed that sorafenib effectively inhibited cell growth and induced apoptosis in chondrosarcoma cells, which was concurrent with inhibition of the expression of phospho‐MEK and phospho‐ERK. Further more the expression levels of cyclin D1, Rb and anti‐apoptotic proteins Bcl‐xl and Mcl‐1 significantly reduced, but no changes in Bcl‐2 and Bax. We although detected the expression of Akt, JNK, p38 and their respective phosphoprotein, but did not found meaningful changes.

Conclusions

Our findings demonstrate that sorafenib inhibited the Ras/Raf/MAPK pathway in a time‐ and dose‐dependent fashion in chondrosarcoma cell lines SW1353 and CRL7891 and suggest that sorafenib may be a new therapeutic option for patients with chondrosarcoma. J. Surg. Oncol. 2010;102:821–826. © 2010 Wiley‐Liss, Inc.
Clinical value of plasma hepatocyte growth factor measurement for the diagnosis of periampullary cancer and prognosis after pancreaticoduodenectomy
Authors: Barakat Omar , Rodriguez Gabriela C. , Raijman Isaac , Allison Paul M. , Nieto Javier , Ozaki Claire F. , Wood Robert P. , Engler David A.
Published: September 2010

Background

Previous studies suggest that serum hepatocyte growth factor (HGF) level may be a useful diagnostic and prognostic biomarker for various tumors. We investigated the utility of plasma HGF level measurements in diagnosing periampullary cancer (PAC).

Methods

Of the patients enrolled in this pilot study (n = 118), 57 had PAC, 21 had benign pancreatic tumor (BPT), 20 had chronic pancreatitis (CP), and 20 were healthy controls. Plasma HGF was measured with ELISA kits. It was measured again at 10 days and 1, 2, 3, 6, and 12 months after pancreaticoduodenectomy (PD).

Results

Plasma HGF levels were significantly higher in PAC patients than in BPT patients, CP patients, or healthy controls. When a cutoff value of 1,120 pg/ml was used, 48/57 (84%) patients with PAC were positive for elevated HGF, but only 6/20 (30%) of patients with CP and none of the controls or patients with BPT were positive for elevated HGF. After PD, HGF levels were significantly elevated at day 10.

Conclusions

Plasma HGF level discriminates well between PAC and other, benign diseases. Therefore, HGF measurement could be a useful addition to the existing array of diagnostic tools for PAC pancreatic cancer. The higher postoperative value may reflect the stress of surgery. J. Surg. Oncol. 2010;102:816–820. © 2010 Wiley‐Liss, Inc.
Measurement of intervertebral disc pressure with T1ρ MRI
Authors: Wang Chenyang , Witschey Walter , Elliott Mark A. , Borthakur Arijitt , Reddy Ravinder
Published: September 2010

The aim of this study is to demonstrate T1ρ MRI's capability for measuring intervertebral disc osmotic pressure. Self‐coregistered sodium and T1ρ‐weighted MR images were acquired on ex vivo bovine intervertebral discs (N = 12) on a 3 T clinical MRI scanner. The sodium MR images were used to calculate effective nucleus pulposus fixed‐charge‐density (mean = 138.2 ± 27.6 mM) and subsequently osmotic pressure (mean = 0.53 ± 0.18 atm), whereas the T1ρ‐weighted images were used to compute T1ρ relaxation maps. A significant linear correlation (R = 0.56, P < 0.01) between nucleus pulposus fixed‐charge‐density and T1ρ relaxation time constant was observed. More importantly, a significant power correlation (R = 0.72, P < 0.01) between nucleus pulposus osmotic pressure as predicted by sodium MRI and T1ρ relaxation time constant was also observed. The current clinical method for assessing disc pressure is discography, which is an invasive procedure that has been shown to have negative effects on disc biomechanical and biochemical properties. In contrast, T1ρ MRI is noninvasive and can be easily implemented in a clinical setting due to its superior signal‐to‐noise ratio compared with sodium MRI. Therefore, T1ρ MRI may serve as a noninvasive clinical tool for the longitudinal evaluation of disc osmotic pressure. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Thin shell analysis from scattered points with maximum‐entropy approximants
Authors: Millán D. , Rosolen A. , Arroyo M.
Published: September 2010

We present a method to process embedded smooth manifolds using sets of points alone. This method avoids any global parameterization and hence is applicable to surfaces of any genus. It combines three ingredients: (1) the automatic detection of the local geometric structure of the manifold by statistical learning methods; (2) the local parameterization of the surface using smooth meshfree (here maximum‐entropy) approximants; and (3) patching together the local representations by means of a partition of unity. Mesh‐based methods can deal with surfaces of complex topology, since they rely on the element‐level parameterizations, but cannot handle high‐dimensional manifolds, whereas previous meshfree methods for thin shells consider a global parametric domain, which seriously limits the kinds of surfaces that can be treated. We present the implementation of the method in the context of Kirchhoff–Love shells, but it is applicable to other calculations on manifolds in any dimension. With the smooth approximants, this fourth‐order partial differential equation is treated directly. We show the good performance of the method on the basis of the classical obstacle course. Additional calculations exemplify the flexibility of the proposed approach in treating surfaces of complex topology and geometry. Copyright © 2010 John Wiley & Sons, Ltd.
Proteomic and PROTEOMEX profiling of mammary cancer progression in a HER‐2/neu oncogene‐driven animal model system
Authors: Croci Stefania , Recktenwald Christian V. , Lichtenfels Rudolf , Nicoletti Giordano , Dressler Sven P. , De Giovanni Carla , Astolfi Annalisa , Palladini Arianna , Shin‐ya Kazuo , Landuzzi Lorena , Nanni Patrizia , Lollini Pier‐Luigi , Seliger Barbara
Published: September 2010

The prevention of mammary carcinoma by immunological strategies targeting the HER‐2/neu receptor has proved to be effective in preclinical models. Thus, a well‐characterized HER‐2/neu oncogene‐driven mammary carcinogenesis model was analysed by various profiling strategies following “triplex” vaccination to identify new candidate targets for breast cancer immunoprevention. 2‐DE‐based proteomic profiling of preneoplastic and tumour lesions versus normal and aged mammary tissue demonstrated that tumour progression was associated with an up‐regulation of molecular chaperones including glucose‐regulated protein (GRP)78 and of proteins favouring cell motility, which was in line with the corresponding transcriptomic profiling data. Furthermore, PROTEOMEX analyses suggested that naturally induced autoantibody responses occur during early phases of mammary cancer progression. Most of the cancer progression‐induced antibodies targeted proteins of normal and preneoplastic mammary glands. However, three proteins were only recognized by sera obtained from vaccinated mice, including 2 isoforms of annexin A6. The distinct expression patterns for annexin A6 and GRP78 during tumour progression were further verified by western blot and/or immunoprecipitation. In addition, an inhibitor‐mediated blockade of GRP78 expression in a model cell line caused a reduced cell growth. Thus, the proteome‐based approaches applied in the murine BALB‐NeuT model might indeed provide candidates for immunoprevention strategies in breast cancer.
Pseudo‐neutral‐loss scan for selective detection of phosphopeptides and N‐glycopeptides using liquid chromatography coupled with a hybrid linear ion‐trap/orbitrap mass spectrometer
Authors: Hsiao He‐Hsuan , Urlaub Henning
Published: September 2010

We describe a novel method, termed “pseudo‐neutral‐loss scan” MS, for selectively probing phosphopeptides and glycopeptides on a LTQ‐Orbitrap mass spectrometer. The instrument has been programmed such that an in‐source CID energy is applied to all species that eluted from LC column and were subsequently ionised in the electrospray ion source. Ion pairs that differ in the mass of a neutral loss of phosphoric acid or monosaccharide residues are automatically selected for CID MS/MS and further for multi‐stage‐activation MS3. Our method should prove useful for a highly selective and sensitive approach to identify phosphopeptides and glycopeptides from purified protein digestion without any further enrichment, and could potentially be of use in more complex mixture.
Proteomic characterization of Her2/neu‐overexpressing breast cancer cells
Authors: Chen Hexin , Pimienta Genaro , Gu Yiben , Sun Xu , Hu Jianjun , Kim Min‐Sik , Chaerkady Raghothama , Gucek Marjan , Cole Robert N. , Sukumar Saraswati , Pandey Akhilesh
Published: September 2010

The receptor tyrosine kinase HER2 is an oncogene amplified in invasive breast cancer and its overexpression in mammary epithelial cell lines is a strong determinant of a tumorigenic phenotype. Accordingly, HER2‐overexpressing mammary tumors are commonly indicative of a poor prognosis in patients. Several quantitative proteomic studies have employed two‐dimensional gel electrophoresis in combination with MS/MS, which provides only limited information about the molecular mechanisms underlying HER2/neu signaling. In the present study, we used a SILAC‐based approach to compare the proteomic profile of normal breast epithelial cells with that of Her2/neu‐overexpressing mammary epithelial cells, isolated from primary mammary tumors arising in mouse mammary tumor virus‐Her2/neu transgenic mice. We identified 23 proteins with relevant annotated functions in breast cancer, showing a substantial differential expression. This included overexpression of creatine kinase, retinol‐binding protein 1, thymosin 4 and tumor protein D52, which correlated with the tumorigenic phenotype of Her2‐overexpressing cells. The differential expression pattern of two genes, gelsolin and retinol binding protein 1, was further validated in normal and tumor tissues. Finally, an in silico analysis of published cancer microarray data sets revealed a 23‐gene signature, which can be used to predict the probability of metastasis‐free survival in breast cancer patients.
Covalent bonded polymer–graphene nanocomposites
Authors: Pramoda K. P. , Hussain H. , Koh H.M. , Tan H. R. , He C. B.
Published: September 2010

This report describes a new route to covalently bonded polymer–graphene nanocomposites and the subsequent enhancement in thermal and mechanical properties of the resultant nanocomposites. At first, the graphite is oxidized by the modified Hummers method followed by functionalization with Octadecylamine (ODA). The ODA functionalized graphite oxides are reacted with methacryloyl chloride to incorporate polymerizable CC functionality at the nanographene platelet surfaces, which were subsequently employed in in situ polymerization of methylmethacrylate to obtain covalently bonded poly(methyl methacrylate) (PMMA)–graphene nanocomposites. The obtained nanocomposites show significant enhancement in thermal and mechanical properties compared with neat PMMA. Thus, even with 0.5 wt % graphene nanosheets, the Tg increased from 119 °C for neat PMMA to 131 °C for PMMA–graphene nanocomposite, and the respective storage modulus increased from 1.29 to 2 GPa. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4262–4267, 2010
Hard nanocomposite comprising stereoregular syndiotactic polypropylene with chemically bonded gold nanoparticles
Authors: Yeh Jie‐Ru , Tseng Fu‐Yuan , Yeh Je‐Yuan , Tsai Jing‐Cherng , Tsiang Raymond Chien‐Chao
Published: September 2010

An effective method to synthesize directly a hard composite material containing uniformly dispersed nanogold particles chemically bonded with a stereospecific, crystalline polymer matrix has been developed. Syndiotactic polypropylene was synthesized and functionalized to have a hydroxyl terminal group (sPPOH) via a metallocene catalysis with a selective chain transfer. Next, sPPOH was activated to react with ethylene sulfide forming the thiol‐terminated polymer, sPPSH. sPPSH was then chemically bonded to gold nanoparticles (AuNPs) formed in situ via a reduction of HAuCl4. The bonding between thiol and AuNP stabilized the AuNPs and led to the formation of sPPAuNPs composite containing uniformly‐dispersed AuNPs of a 19–40 nm size without noticeable aggregation. Furthermore, the chemical bonding of AuNPs has afforded sPPAuNPs a thermal degradation temperature (TD) 49.4 °C higher than the pristine sPP or sPPOH and 25.7 °C higher than sPPSH without any adverse effect on the crystalline temperature and melting temperature. In addition, the characteristic UV‐Vis absorption wavelength of sPPAuNPs remains the same at various temperatures, thus indicating the independence of optical property on temperature as well as the good thermal stability of the sPPAuNPs composite. 1H NMR, 13C NMR, FESEM, STEM, XPS, TGA and DSC were used to investigate the molecular structure, morphology and thermal properties of the resulting sPPAuNPs nanocomposite. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
The influence of solution‐state conditions and stirring rate on the assembly of poly(acrylic acid)‐containing amphiphilic triblock copolymers with multi‐amines
Authors: Sorrells Jennifer L. , Tsai Ying‐Hsin , Wooley Karen L.
Published: September 2010

In the effort towards making nanoscale objects and assemblies feasible for use as functional materials, it is imperative to obtain control over the fundamental architectures and essential to understand what experimental conditions cause the manifestation of specific morphologies. A number of factors are known to influence the shape during the self‐assembly of amphiphilic block copolymers in solution, including solvent composition, polymer length, hydrophobicity versus hydrophilicity, as well as the addition of additives that can interact with segments of the block copolymers. This research, focused on developing an understanding of the micellar architectures accessed by the amphiphilic triblock copolymer of acrylic acid, methyl acrylate, and styrene, PAA85‐b‐PMA40‐b‐PS35, as a function of the stirring rate, together with other factors, when undergoing coassembly with ethylenediamine or diethylenetriamine in water/tetrahydrofuran solutions. The work demonstrates that the rate at which the polymer solution was stirred impacts the shape of the solution‐state assemblies formed by the triblock copolymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Designed organo‐layered silicates as nanoreactors for 1,3‐butadiene stereospecific polymerization toward rubber nanocomposites synthesis
Authors: Leone Giuseppe , Boglia Aldo , Bertini Fabio , Canetti Maurizio , Ricci Giovanni
Published: September 2010

Organo‐modified layered silicates were synthesized and used as inorganic carriers for CoCl2(PtBu2Me)2‐MAO catalyst in the polymerization of 1,3‐butadiene, yielding cis‐1,4‐enriched polybutadiene. The organoclays were prepared by: (i) intercalation of (ar‐vinyl‐benzyl)trimethyl ammonium chloride salt through an ion exchange reaction, and (ii) the edge‐surface grafting by trimethylchlorosilane. The ammonium modifier acts as “spacer” increasing the layer d‐spacing and as “filler” favoring the silylation of the edge‐surface clay hydroxyls. The grafted silane prevents the MAO cocatalyst from reacting with the edge‐OHs, by forcing it to react within the interlayer clay region. MAO lead to methylation of the cobalt complex and carbanion abstraction to give a cobalt‐methyl cation that is stabilized by the MAO anion. The nanoconfined cationic alkylated species insert the butadiene on the Co‐Me bond affording the growth of the polymer chains within the clay layers. The growing of the macromolecular chains fills the interlayer silicate region giving an intercalated polybutadiene rubber nanocomposite. The role of the silicate organo modification on the heterogeneous catalyst structural features, the polymerization behavior and the nanocomposite structures are discussed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Facile, one‐pot synthesis of aromatic diamine‐based phosphinated benzoxazines and their flame‐retardant thermosets
Authors: Lin Ching Hsuan , Lin Hung Tse , Sie Jhao Wei , Hwang Kuen Yuan , Tu An Pang
Published: September 2010

Three aromatic diamine‐based, phosphinated benzoxazines (7–9) were prepared from three typical aromatic diamines—4,4′‐diamino diphenyl methane (1), 4,4′‐diamino diphenyl sulfone (2), and 4,4′‐diamino diphenyl ether (3) by a one‐pot procedure. To clarify the reaction mechanism, a two‐pot procedure was applied, in which the reaction intermediates (4–6) were isolated for characterization. The structures of intermediates and benzoxazines were confirmed by high resolution mass, IR, and 1D and 2D‐NMR spectra. In addition to self‐polymerization, (7–9) were copolymerized with cresol novolac epoxy (CNE). After curing, the homopolymers of P(7–9) are brittle while the copolymers of (7–9)/CNE are tough. Dynamic mechanical analysis shows the Tgs of (7–9)/CNE copolymers are 187, 190, and 171 °C, respectively. Thermal mechanical analysis shows the CTEs of (7–9)/CNE copolymers are 46, 38, and 46 ppm, respectively. All the (7–9)/CNE copolymers belong to an UL‐94 V‐0 grade, demonstrating good flame retardancy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Self‐emulsification and surface modification effect of fluorinated amphiphilic acrylate graft copolymers
Authors: Cha Mi Sun , Kim Jae Won , Ha Jong‐Wook , Park In Jun , Lee Soo‐Bok , Yang Tingting , Cheng Shiyuan
Published: September 2010

We report on self‐emulsification and surface modification effect of novel fluorinated amphiphilic graft copolymers prepared with perfluoroalkyl acrylate and 2‐dimethylaminoethyl methacrylate using simple macromonomer technique and radical copolymerization. The interfacial properties of amphiphilic graft copolymers were characterized with light scattering, contact angle measurement, and X‐ray photoelectron spectroscopy. The preparation of fluorinated amphiphilic graft copolymer was verified using nuclear magnetic resonance and Fourier transform infrared spectroscopy. It was observed that the fluorinated amphiphilic graft copolymer has both strong hydrophobic and hydrophilic properties and shows self‐emulsification ability without addition of external surfactants. The graft copolymer shows very low surface energy even though the copolymer has low content of hydrophobic segment and better performance than random copolymer for low‐energy surface modification. The addition of small amount of the graft copolymer (0.1 wt %) into the base poly(methyl methacrylate) was sufficient to lower the surface energy less than that of poly(tetrafluoroethylene). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Fundamental study of crystallization, orientation, and electrical conductivity of electrospun PET/carbon nanotube nanofibers
Authors: Mazinani Saeedeh , Ajji Abdellah , Dubois Charles
Published: September 2010

The morphology, structure, and properties of polyethylene terephthalate (PET)/Carbon Nanotubes (CNT) conductive nanoweb were studied in this article. Nanocomposite nanofibers were obtained through electrospinning of PET solutions in trifluoroacetic acid (TFA)/dichloromethane (DCM) containing different concentrations and types of CNTs. Electrical conductivity measurements on nanofiber mats showed an electrical percolation threshold around 2 wt % multi‐wall carbon nanotubes (MWCNT). The morphological analysis results showed smoother nanofibers with less bead structures development when using a rotating drum collector especially at high concentrations of CNTs. From crystallographic measurements, a higher degree of crystallinity was observed with increasing CNT concentrations above electrical percolation. Spectroscopy results showed that both PET and CNT orientation increased with the level of alignment of the nanofibers when the nanotube concentration was below the electrical percolation threshold; while the orientation factor was reduced for aligned nanofibers with higher content in CNT. Considerable enhancement in mechanical properties, especially tensile modulus, was found in aligned nanofibers; at least six times higher than the modulus of random nanofibers at concentrations below percolation. The effect of alignment on the mechanical properties was less important at higher concentrations of CNTs, above the percolation threshold. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2052–2064, 2010
Density functional study on the effect of substituent group for the monomer of donor‐acceptor copolymer
Authors: Sun Lei , Bai Fu‐Quan , Zhao Zeng‐Xia , Yang Bao‐Zhu , Zhang Hong‐Xing
Published: September 2010

The effect of the substituent groups (alkyl or aryl) on the structure, electronic, optical properties, ionization potentials (IPs), electron affinities (EAs), and reorganization energy of the donor–acceptor monomers 5,8‐di‐2‐thienyl‐quinoxaline (T[Q]T), 4,9‐di‐2‐thienylpyrazine[2,3‐g]quinoxaline (T[PQ]T) were studied theoretically. The lowest‐lying absorption in assigned to π→π* transition, and the fluorescence can be described as originating from the 1[ππ*] excited state. The lowest‐lying absorption and emission spectrum of T[Q]T and T[PQ]T with alkyl groups exhibit blue‐shifted, while T[Q]T and T[PQ]T with aryl groups exhibit the opposite result. The extra absorption bond at 400 nm of T[Q]T‐Bph is contributed by the π‐π* transitions between the biphenyl and acceptor fragment. Orbital compositions transfer coefficient (χ) of the donor in LUMOs is reduced with the aryl groups on the acceptor, which illuminates that the aryl contributes to intramolecular charge transfer, and the result is in accord with the analysis of reorganization energy. IPs is brought down by both of the alkyl and aryl groups, but EAs is raised only by aryl, therefore, aryl is conductive to forming excitons for D‐A‐D molecule. Consequently, T[Q]T and T[PQ]T with aryl groups are more reasonable monomers of donor–acceptor copolymers as a solar cell materials comparing with the alkyl‐introduced ones. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
Dynamic light scattering studies of ionic and nonionic polymer gels with continuous and discontinuous volume transitions
Authors: Mccoy J. L. , Muthukumar M.
Published: September 2010

We have performed dynamic light scattering experiments on poly(acrylamide)‐poly(acrylic acid) copolymer gels with controlled crosslink density and copolymer composition, by varying the temperature, amount and valency of added salt, pH, and solvent quality. Our systematic study provides several insights. The correlation length for the monomer density fluctuations, as inferred from the measured diffusion coefficient, is too small to be identified as the mesh size of the gel. The correlation length in an ionic gel, which is found to be smaller than that for an equivalent gel without ionization. Comparison of swelling ratio with the diffusion coefficient shows that these quantities are not simply geometrically related to each other. When a discontinuous volume phase transition is induced by gradually varying the solvent quality, the diffusion coefficient exhibits a pretransitional reduction by two orders of magnitude even before the gel collapse. These findings provoke a need for new theoretical approaches for describing the elastic modes of polyelectrolyte gels. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
Effect of PBT molecular weight and reactive compatibilization on the dispersed‐phase coalescence of PBT/SAN blends
Authors: Larocca Nelson M. , Ito Edson N. , Rios Carlos Triveño , Pessan Luiz A. , Bretas Rosario E. S. , Hage Elias
Published: September 2010

Poly(butylene terephthalate) (PBT)/styrene‐acrylonitrile copolymer (SAN) blends were investigated with respect to their phase morphology. The SAN component was kept as dispersed phase and PBT as matrix phase and the PBT/SAN viscosity ratio was changed by using different PBT molecular weights. PBT/SAN blends were also compatibilized by adding methyl methacrylate‐co‐glycidyl methacrylate‐co‐ethyl acrylate terpolymer, MGE, which is an in situ reactive compatibilizer for melt blending. In noncompatibilized blends, the dispersed phase particle size increased with SAN concentration due to coalescence effects. Static coalescence experiments showed evidence of greater coalescence in blends with higher viscosity ratios. For noncompatibilized PBT/SAN/MGE blends with high molecular weight PBT as matrix phase, the average particle size of SAN phase does not depend on the SAN concentration in the blends. However noncompatibilized blends with low molecular weight PBT showed a significant increase in SAN particle size with the SAN concentration. The effect of MGE epoxy content and MGE molecular weight on the morphology of the PBT/SAN blend was also investigated. As the MGE epoxy content increased, the average particle size of SAN initially decreased with both high and low molecular weight PBT phase, thereafter leveling off with a critical content of epoxy groups in the blend. This critical content was higher in the blends containing low molecular weight PBT than in those with high molecular weight PBT. At a fixed MGE epoxy content, a decrease in MGE molecular weight yielded PBT/SAN blends with dispersed nanoparticles with an average size of about 40 nm. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
The crystal–crystal transition in hydrogenated ring‐opened polynorbornenes: Tacticity, crystal thickening, and alignment
Authors: Bishop John P. , Register Richard A.
Published: September 2010

At a temperature Tcc well below its melting point Tm, hydrogenated ring‐opened polynorbornene (hPN) is known to exhibit a crystal–crystal transition; above Tcc, the hPN chains are rotationally disordered. This transition is examined in a series of hPNs polymerized with different Mo‐ and Ru‐based catalysts, each of which imparts a slightly different tacticity to the polymer. Tcc is found to correlate well with the ratio of meso to racemo dyads (m:r); small changes in m:r (from 0.8 to 1.1) are sufficient to raise Tcc by nearly 20 °C. For the homogeneous Mo‐based “Schrock‐type” catalyst examined, such a change in m:r is easily achieved by simply adding the reversibly binding ligand trimethylphosphine during polymerization. Tcc approaches Tm with increasing m:r, indicating that r dyads stabilize the rotationally disordered structure. When heated above Tcc, hPN crystals thicken at a rate much greater than conventional three‐dimensionally ordered crystals, but below the rates shown by the two‐dimensional hexagonal (columnar) phase formed by some polymers, reflecting the intermediate level of order and chain mobility present in the high‐temperature hPN crystal phase. Solid‐state processing of hPN between Tcc and Tm yields highly aligned macroscopic specimens. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
Solvent‐induced lid opening in lipases: A molecular dynamics study
Authors: Rehm Sascha , Trodler Peter , Pleiss Jürgen
Published: September 2010

In most lipases, a mobile lid covers the substrate binding site. In this closed structure, the lipase is assumed to be inactive. Upon activation of the lipase by contact with a hydrophobic solvent or at a hydrophobic interface, the lid opens. In its open structure, the substrate binding site is accessible and the lipase is active. The molecular mechanism of this interfacial activation was studied for three lipases (from Candida rugosa, Rhizomucor miehei, and Thermomyces lanuginosa) by multiple molecular dynamics simulations for 25 ns without applying restraints or external forces. As initial structures of the simulations, the closed and open structures of the lipases were used. Both the closed and the open structure were simulated in water and in an organic solvent, toluene. In simulations of the closed lipases in water, no conformational transition was observed. However, in three independent simulations of the closed lipases in toluene the lid gradually opened. Thus, pathways of the conformational transitions were investigated and possible kinetic bottlenecks were suggested. The open structures in toluene were stable, but in water the lid of all three lipases moved towards the closed structure and partially unfolded. Thus, in all three lipases opening and closing was driven by the solvent and independent of a bound substrate molecule.
Towards establishing good practice in the use of computer prediction
Authors: Judson Philip Neville
Published: September 2010

Recent developments in national and international legislation encourage the submission of computer predictions to support chemical registration, in order to reduce dependency on animal experiments. The Organisation for Economic Cooperation and Development (OECD) has issued guidelines for describing and evaluating such prediction models. This paper suggests that operating procedures and guidelines are needed for good practice in their development and application. Illustrative examples are provided of the sorts of issues that need to be considered and the possible rules that might be drawn up. Copyright © 2010 John Wiley & Sons, Ltd.
Mass spectrometric characterization of gelsolin isoforms
Authors: Pottiez G. , Haverland N. , Ciborowski P.
Published: September 2010

Gelsolin is the most widely expressed member of the actin capping and severing family of proteins. There are two isoforms of gelsolin: isoform 1, a secretory (plasma) protein that is 51 amino acids longer than isoform 2, a cytosolic protein, at the N‐terminus; the first 27 amino acids is a signal sequence. Both isoforms are coded by a single gene and differ as a result of alternative initiation site/splicing. The level of gelsolin in the blood and cerebrospinal fluid (CSF) is altered in many diseases including amyloidoses and other neurodegenerative disorders. Although quantitative analysis of gelsolin has been reported, lack of suitable antibodies makes it impossible to differentiate these two isoforms by immunodetection techniques and no other technique is available. Therefore, ambiguity exists whether gelsolin present in circulation is isoform 1 or also isoform 2 released from lysed cells. We report in this communication a mass spectrometric approach to identify isoform 1 of gelsolin immunopurified from human plasma and CSF. Recombinant isoform 1 was used as reference. Copyright © 2010 John Wiley & Sons, Ltd.
Finite element modelling of maxillofacial surgery and facial expressions—a preliminary study
Authors: Beldie Liliana , Walker Brian , Lu Yongtao , Richmond Stephen , Middleton John
Published: September 2010

Background

Recent advances in diagnostic imaging and associated software have enabled the transformation of anatomical structures into finite element (FE) models facilitating computerized facial modelling. The work presented employs personalized imaging data of facial anatomical structures for use in planning and predicting the outcome of maxillofacial surgery. The current process relies on either freehand planning and/or commercial two‐dimensional (2D) and three‐dimensional (3D) surgical planning software packages, but the validity of these software packages has been questioned. In this paper, the finite element technique was used to predict the outcome of maxillofacial surgery.

Methods

A finite element facial model was created, based on patient specific bone and skin image data, combined with generic muscle data. The model was used for two distinct purposes: simulation of the maxillofacial surgery and simulation of facial expressions pre‐ and post‐surgery. This combination allowed for an improved prediction of surgery outcome. Commercial software was used for creating the FE facial model from the original image data, and LS‐DYNA® was the analysis code used for the purpose of the FE simulation.

Results

The results from the simulation of maxillofacial surgery showed an overall agreement of 85% with the patient data at 6 months post‐surgery and the error was generally contained within a ± 2 mm threshold.

Conclusions

The results show that the approach of using commercial FE software tools to create a detailed and anatomically accurate patient specific model for simulation of maxillofacial surgery, as well as facial expressions, can be applied in facial surgery planning. As the study was based on data collected from one patient, further work is needed in which additional subjects can be assessed. Copyright © 2010 John Wiley & Sons, Ltd.
Domestic mindsets and early international performance: The moderating effect of global industry conditions
Authors: Nadkarni Sucheta , Herrmann Pol , Perez Pedro David
Published: September 2010

We develop and test a sensemaking model of early internationalization that ties domestic mindsets to international industry conditions and early international performance. Our central contention is that the fit between international industry conditions and domestic mindsets will lead to superior early international performance. We test this contention with a sample of 178 large and established domestic firms from 20 industries. Our results highlight the role of domestic mindsets in the early phases of internationalization and prescribe the types of domestic mindsets needed to maximize early international performance in global, multi‐domestic, and transnational industry conditions. Our results also provide valuable insights to top managers of large and established firms on how to reduce the risk of failure and how to successfully prepare for and cope with international environments by matching their domestic mindsets with international industry environments. Copyright © 2010 John Wiley & Sons, Ltd.
Anatase Mesoporous TiO2 Nanofibers with High Surface Area for Solid‐State Dye‐Sensitized Solar Cells
Authors: Zhang Wei , Zhu Rui , Ke Lin , Liu Xizhe , Liu Bin , Ramakrishna Seeram
Published: September 2010

Mesoporous nanofibers (NFs) with a high surface area of 112 m2/g have been prepared by electrospinning technique. The structures of mesoporous NFs and regular NFs are characterized and compared through scanning electron microscope (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD) and selected area electron diffraction (SAED) studies. Using mesoporous TiO2 NFs as the photoelectrode, solid‐state dye‐sensitized solar cells (SDSCs) have been fabricated employing D131 as the sensitizer and P3HT as the hole transporting material to yield an energy conversion efficiency (η) of 1.82%. A Jsc of 3.979 mA cm−2 is obtained for mesoporous NF‐based devices, which is 3‐fold higher than that (0.973 mA cm−2) for regular NF‐based devices fabricated under the same condition (η = 0.42%). Incident photon‐to‐current conversion efficiency (IPCE) and dye‐desorption test demonstrate that the increase in Jsc is mainly due to greatly improved dye adsorption for mesoporous NFs as compared to that for regular NFs. In addition, intensity modulated photocurrent spectroscopy (IMPS) and intensity modulated photovoltage spectroscopy (IMVS) measurements indicate that the mesopores on NF surface have very minor effects on charge transport and collection. Initial aging test proves good stability of the fabricated devices, which indicates the promise of mesoporous NFs as photoelectrode for low‐cost SDSCs.
Magnetic Luminescent Porous Silicon Microparticles for Localized Delivery of Molecular Drug Payloads
Authors: Gu Luo , Park Ji‐Ho , Duong Kim H. , Ruoslahti Erkki , Sailor Michael J.
Published: September 2010

Magnetic manipulation, fluorescent tracking, and localized delivery of a drug payload to cancer cells in vitro is demonstrated, using nanostructured porous silicon microparticles as a carrier. The multifunctional microparticles are prepared by electrochemical porosification of a silicon wafer in a hydrofluoric acid‐containing electrolyte, followed by removal and fracture of the porous layer into particles using ultrasound. The intrinsically luminescent particles are loaded with superparamagnetic iron oxide nanoparticles and the anti‐cancer drug doxorubicin. The drug‐containing particles are delivered to human cervical cancer (HeLa) cells in vitro, under the guidance of a magnetic field. The high concentration of particles in the proximity of the magnetic field results in a high concentration of drug being released in that region of the Petri dish, and localized cell death is confirmed by cellular viability assay (Calcein AM).
Likelihood ratio‐based quality control for nuchal translucency measurements at 11–14 weeks of gestation
Authors: Salomon L. J. , Porcher R. , Stirnemann J. J. , Bernard J. P. , Ville Y.
Published: September 2010

Objective

To develop a quantitative quality control process of nuchal translucency (NT) measurement at 11–14 weeks of gestation based on the mixture model, characterized by analysis of the corresponding distribution of the likelihood ratio (LR).

Methods

Based on the published mixture model for NT measurement in the first trimester, we simulated the expected distribution of NT and the corresponding LR. This approach was then tested for the quality control of 15 048 NT measurements performed by four operators trained and certified by The Fetal Medicine Foundation. The new quality control approach based on LR was compared with existing processes based on NT plots, multiples of the median (MoMs) and analysis of the 95th centile.

Results

Each operator contributed 2176–4730 examinations. Median, 5th and 95th centile of NT values ranged from 1.4 to 1.6, 1.0 to 1.0 and 2.2 to 2.6 mm, respectively. Median of NT‐MoM values ranged from 0.83 to 0.95. Analysis of the distribution of NT measurements confirmed departure from the assumptions of the delta‐NT and NT‐MoM models. Analysis of LR distributions demonstrated a significant difference between observed and expected distributions for all operators (P < 10−4).

Conclusion

An LR‐based quality control process is feasible at 11–14 weeks of gestation. Because it is more sensitive to measurement bias around the critical area of the 95th centile, its use should be encouraged. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.