bluuebunny/crossref_metadata_2025 huggingface dataset:
Titanium surfaces with nanotopography modulate cytokine production in cultured human gingival fibroblasts
Authors: Schwartz‐Filho Humberto Osvaldo , Morandini Ana Carolina Faria , Ramos‐Junior Erivan Schnaider , Jimbo Ryo , Santos Carlos Ferreira , Marcantonio Elcio , Wennerberg Ann , Marcantonio Rosemary Adriana Chiérici
Published: May 2012

Implant topography is an important factor that influences many cell types. To understand the role of topography in the inflammatory events, we evaluated the response of human gingival fibroblasts (HGFs) by the release pattern of cytokines. HGFs were cultured on Ti discs for 24 and 48 h. Four different surface treatments were used: machining method (turned), blasting followed by an acid‐etching method (BAE), oxidative nanopatterning (ON) method, and an association of blasting followed by an acid‐etching plus oxidative nanopatterning (BAE+ON) method. Extracellular levels of IL‐6, IL‐8, transforming growth factor beta (TGF‐β), IL‐4, and IL‐10 were measured by enzyme‐linked immunosorbant assay. Increased levels of IL‐6 and IL‐8 were observed in all surfaces after 24 h which decreased after 48 h. BAE, ON, and BAE+ON surfaces showed a reduction in IL‐6 levels compared with the turned after 48 h (p < 0.05). On one hand, IL‐8 production was lower in BAE+ON in comparison to the turned surface (p < 0.05). On the other hand, IL‐4 showed increased levels with 48 h, which were significantly different between turned, BAE, and ON surfaces, but not with BAE+ON. Additionally, TGF‐β and IL‐10 production were not detected. This study indicates that nanotopography might be important in the modulation of the inflammatory response in cultured HGFs. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:2629–2636, 2012.
Optimizing siRNA efficacy through alteration in the target cell‐adhesion substrate interaction
Authors: Khormaee Sariah , Ali Omar A. , Chodosh James , Mooney David J.
Published: May 2012

The clinical potential of short interfering RNA (siRNA) based therapeutics remains hindered by the challenge of delivering enough siRNA into the cytoplasm to yield a clinically relevant effect. Although much research has focused on optimizing delivery vehicles for this class of molecules, considerably less is known about the microenvironmental influences on the response of target cells to siRNA. The substrate to which cells adhere is one component of the microenvironment that can modulate cellular behavior. Here, we tested the hypothesis that modulating the properties of cellular adhesion substrates can alter siRNA efficacy. Specifically, cationic lipid complexed siRNA particles were applied to U251 cells seeded on alginate hydrogel surfaces with systematic variation in elastic modulus and integrin ligand arginine‐glycine‐aspartate (RGD) peptide density. These experiments revealed no change in siRNA‐mediated eGFP knockdown over the elastic modulus range tested (53–133 kPa). However, an eightfold increase in RGD content of the alginate growth substrate resulted in an increase in siRNA knockdown efficacy from 25 ± 12% to 52 ± 10%, a more than twofold increase in silencing. Our results identify control of the cell‐adhesion substrate interaction as a modulator of siRNA protein silencing efficacy. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:2637–2643, 2012.
Progesterone and calcitriol attenuate inflammatory cytokines CXCL1 and CXCL2 in ovarian and endometrial cancer cells
Authors: Kavandi Leyla , Collier Michael A. , Nguyen Huyen , Syed Viqar
Published: May 2012

Cytokines/chemokines are key players in cancer‐related inflammation. Increasing evidence suggests that chemokines produced by tumor cells are the mediators of metastasis. Thus, agents that can downregulate chemokines expression have potential against cancer metastasis. We have previously shown inhibition of ovarian and endometrial cancer cell growth with progesterone and calcitriol. In the present study, we evaluated the effect of these two agents on the expression of inflammatory genes. Using a RT‐PCR array of inflammatory cytokines/chemokines and their receptors, we found a marked attenuation of CXCL1 and CXCL2 (GRO‐α and ‐β) in cancer cells by both treatments. Knockdown of NFκB resulted in a reduced expression of CXCL1 and CXCL2 and the inhibitory effect of progesterone and calcitriol on the expression of chemokines was abrogated in NFκB‐silenced cancer cells. Silencing of IκBα increased the expression of CXCL1 and CXCL2 in cancer cells, which can be attributed to the increased activation of NFκB‐p65, caused by the lack of its inhibitor. Progesterone and calcitriol‐induced inhibition was abolished in IκBα‐knockdown cells. Our results demonstrate that suppression of IκBα phosphorylation by progesterone and calcitriol contributes to the reduced expression of CXCL1 and CXCL2. Downregulation of CXCL1 and CXCL2 was associated with a marked inhibition of metastasis‐promoting genes. Overall, our results indicate that progesterone and calcitriol inhibit IκBα phosphorylation, NFκB activation, and the expression of NFκB regulated metastasis promoting genes. These results provide attractive data for the possible use of progesterone and calcitriol in the management of endometrial and ovarian tumors. J. Cell. Biochem. 113: 3143–3152, 2012. © 2012 Wiley Periodicals, Inc.
Comparative cellular and molecular analyses of pooled bone marrow multipotent mesenchymal stromal cells during continuous passaging and after successive cryopreservation
Authors: Mamidi Murali Krishna , Nathan Kavitha Ganesan , Singh Gurbind , Thrichelvam Saratha Thevi , Mohd Yusof Nurul Ain Nasim , Fakharuzi Noor Atiqah , Zakaria Zubaidah , Bhonde Ramesh , Das Anjan Kumar , Majumdar Anish Sen
Published: May 2012

The clinical application of human bone marrow derived multipotent mesenchymal stromal cells (MSC) requires expansion, cryopreservation, and transportation from the laboratory to the site of cell implantation. The cryopreservation and thawing process of MSCs may have important effects on the viability, growth characteristics and functionality of these cells both in vitro and in vivo. More importantly, MSCs after two rounds of cryopreservation have not been as well characterized as fresh MSCs from the transplantation perspective. The objective of this study was to determine if the effect of successive cryopreservation of pooled MSCs during the exponential growth phase could impair their morphology, phenotype, gene expression, and differentiation capabilities. MSCs cryopreserved at passage 3 (cell bank) were thawed and expanded up to passage 4 and cryopreserved for the second time. These cells (passive) were then thawed and cultured up to passage 6, and, at each passage MSCs were characterized. As control, pooled passage 3 cells (active) after one round of cryopreservation were taken all the way to passage 6 without cryopreservation. We determined the growth rate of MSCs for both culture conditions in terms of population doubling number (PDN) and population doubling time (PDT). Gene expression profiles for pluripotency markers and tissue specific markers corresponding to neuroectoderm, mesoderm and endoderm lineages were also analyzed for active and passive cultures of MSC. The results show that in both culture conditions, MSCs exhibited similar growth properties, phenotypes and gene expression patterns as well as similar differentiation potential to osteo‐, chondro‐, and adipo‐lineages in vitro. To conclude, it appears that successive or multiple rounds of cryopreservation of MSCs did not alter the fundamental characteristics of these cells and may be used for clinical therapy. J. Cell. Biochem. 113: 3153–3164, 2012. © 2012 Wiley Periodicals, Inc.
Nestin protects mouse podocytes against high glucose‐induced apoptosis by a Cdk5‐dependent mechanism
Authors: Liu Wei , Zhang Yue , Hao Jun , Liu Shuxia , Liu Qingjuan , Zhao Song , Shi Yonghong , Duan Huijun
Published: May 2012

Podocyte apoptosis contributes to the pathogenesis of diabetic nephropathy (DN). However, the mechanisms that mediate hyperglycemia‐induced podocyte apoptosis remain poorly understood. Recent findings indicate that the disruption of the cytoskeleton is related to the podocyte apoptosis. In the present study, we investigated the involvement of nestin, an important cytoskeleton‐associated class VI intermediate filament (IF) protein, in the high glucose (HG)‐induced podocyte apoptosis. Our data showed that HG decreased the expression level of nestin, either mRNA or protein, in a time‐dependent manner in cultured podocytes. Also, through knockdown of nestin expression by miRNA interference, the HG‐induced podocyte apoptotic rate was significantly increased. The expression of cleaved caspase‐3 was also markedly elevated. Considering that nestin is a substrate of cyclin‐dependent kinase 5 (Cdk5), we further assessed the expression of Cdk5 in HG‐treated podocytes. The results showed that HG stimulation increased the protein and mRNA expression of Cdk5 in a time‐dependent manner in cultured mouse podocytes. The protein activator of Cdk5, p35, was also increased in a time‐dependent manner by HG stimulation, and downregulation of Cdk5 by miRNA interference attenuated the nestin reduction in HG‐treated podocytes; the HG‐induced podocyte apoptosis, the increased cleaved caspase‐3 expression and the Bax/Bcl‐2 ratio were all effectively attenuated. These data suggested that nestin, which is dependent on Cdk5 regulation, plays a cytoprotective role in HG‐induced podocyte apoptosis. J. Cell. Biochem. 113: 3186–3196, 2012. © 2012 Wiley Periodicals, Inc.
Silicate modulates the cross‐talk between osteoblasts (SaOS‐2) and osteoclasts (RAW 264.7 cells): Inhibition of osteoclast growth and differentiation
Authors: Schröder H.C. , Wang X.H. , Wiens M. , Diehl‐Seifert B. , Kropf K. , Schloßmacher U. , Müller W.E.G.
Published: May 2012

It has been shown that inorganic monomeric and polymeric silica/silicate, in the presence of the biomineralization cocktail, increases the expression of osteoprotegerin (OPG) in osteogenic SaOS‐2 sarcoma cells in vitro. In contrast, silicate does not affect the steady‐state gene expression level of the osteoclastogenic ligand receptor activator of NF‐κB ligand (RANKL). In turn it can be expected that the concentration ratio of the mediators OPG/RANKL increases in the presence of silicate. In addition, silicate enhances the growth potential of SaOS‐2 cells in vitro, while it causes no effect on RAW 264.7 cells within a concentration range of 10–100 µM. Applying a co‐cultivation assay system, using SaOS‐2 cells and RAW 264.7 cells, it is shown that in the presence of 10 µM silicate the number of RAW 264.7 cells in general, and the number of TRAP+ RAW 264.7 cells in particular markedly decreases. The SaOS‐2 cells retain their capacity of differential gene expression of OPG and RANKL in favor of OPG after exposure to silicate. It is concluded that after exposure of the cells to silicate a factor(s) is released from SaOS‐2 cells that causes a significant inhibition of osteoclastogenesis of RAW 264.7 cells. It is assumed that it is an increased secretion of the cytokine OPG that is primarily involved in the reduction of the osteoclastogenesis of the RAW 264.7 cells. It is proposed that silicate might have the potential to stimulate osteogenesis in vivo and perhaps to ameliorate osteoporotic disorders. J. Cell. Biochem. 113: 3197–3206, 2012. © 2012 Wiley Periodicals, Inc.
Rationalization of the behavior of M2(CH3CS2)4I (M = Ni, Pt) chains at room temperature from periodic density functional theory and ab initio cluster calculations
Authors: Tabookht Zahra , López Xavier , de Graaf Coen , Guihéry Nathalie , Suaud Nicolas , Benamor Nadia
Published: May 2012

The electrical conductivities and plausible charge‐ordering states in the room temperature (r.t.) phase for MMX chains [Ni2(dta)4I]∞ and [Pt2(dta)4I]∞ (dta = CH3CS) have been analyzed with periodic density functional theory (DFT) and correlated ab initio calculations combined with the effective Hamiltonian theory. Periodic DFT calculations show a more delocalized nature of the ground state in [Pt2(dta)4I]∞ compared to [Ni2(dta)4I]∞, which features a rather large energy gap between the occupied and empty bands, and charge polarized dimer units. A larger electrical conductivity for the Pt chain can be expected, especially because the Fermi level lies within a band with contributions from Pt and I orbitals. Electronic structure parameters extracted from ab initio cluster calculations show that the large difference between the observed conductivities at 300 K for Ni and Pt compounds, of 3 orders of magnitude, cannot be explained from the parameters extracted from an embedded M2(dta)4I2 dimer fragment alone. When tetramer fragments are considered, we observe that the interdimer transfer integral (t) between neighboring M2 units connected by an iodine atom at correlated level is comparable in both chains. On the other hand, the energy to transfer an electron from a dimer to the neighboring one (Coulomb repulsion U) is three times larger in the Ni compound with respect to the Pt chain, in line with the poor conductivity of the former. The electronic structure of the M4(dta)8I3 fragment points to an alternate charge‐polarization state for Ni and an average valence state for Pt when the r.t. X‐ray structure is considered. © 2012 Wiley Periodicals, Inc.
Computational investigations on covalent dimerization/oligomerization of polyacenes: Is it relevant to soot formation?
Authors: Koley D. , Arunan E. , Ramakrishnan S.
Published: May 2012

We have postulated a novel pathway that could assist in the nucleation of soot particles through covalent dimerization and oligomerizations of a variety of PAHs. DFT calculations were performed with the objective of obtaining the relative thermal stabilities and formation probabilities of oligomeric species that exploit the facile dimerization that is known to occur in linear oligoacenes. We propose that the presence of small stretches of linear oligoacence (tetracene or longer) in extended PAH, either embedded or tethered, would be adequate for enabling the formation of such dimeric and oligomeric adducts; these could then serve as nuclei for the growth of soot particles. Our studies also reveal the importance of π‐stacking interactions between extended aromatic frameworks in governing the relative stabilities of the oligomeric species that are formed. © 2012 Wiley Periodicals, Inc.
Gill‐arch musculature of the quillback carpiodes cyprinus (cypriniformes: catostomidae) with a comparison to cyprinids
Authors: Grey Ericka A. , Mabee Paula M.
Published: May 2012

Although the gill‐arch osteology of Cypriniformes has been well studied, comparable works on gill‐arch musculature are scarce. The focus of previous studies has been on Cyprinidae while other families have received little or no attention. Consequently, generalizations for Cypriniformes have been made from the musculature of cyprinid gill‐arches. This study describes the gill‐arch musculature of a catostomid, the quillback Carpiodes cyprinus, and demonstrates that there are striking differences in the overall gill‐arch musculature of catostomids in comparison to cyprinids, especially in the dorsal gill‐arch region. Of the 23 muscles found in the dorsal gill‐arch region of cyprinids, only 13 were present in C. cyprinus. Muscles that are absent include adductores 1–5, levator internus 4, levator ceratobranchialis 5 accessorius, retractor ceratobranchialis 5 externus, retractor ceratobranchialis 5 internus, and the retractor ceratobranchialis 5 transversus. In the ventral gill‐arch region, the rectus communis is absent. The derived scrolling shape of the dorsal gill‐arch skeleton associated with food processing is likely related to the change in musculature. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.
Low‐resolution Raman spectroscopy over a wide spectral range with a single‐diffraction order arrayed‐waveguide grating
Authors: Baclig A. C. , Ismail N. , de Ridder R. M. , Pollnau M. , Caspers P. J. , Puppels G. J.
Published: May 2012

An integrated arrayed‐waveguide grating (AWG) fabricated in silicon oxynitride (SiON) technology is used as the wavelength separation and selection element for Raman spectroscopy. With a spectral resolution of 5.5 nm and a free spectral range of 215 nm, the AWG enables wavelength separation of the full Raman fingerprint region in a single diffraction order without order overlap. It is demonstrated that Raman signal detection of cyclohexane with the AWG is feasible and that the information on position and relative intensities of the Raman bands of cyclohexane are preserved. A detailed description of the signal processing methodology to obtain AWG‐based Raman measurements corrected for instrument response is presented. The Raman measurement based on the integrated intensity output of the device corresponds well to the expected relative intensity channel output of the AWG. Raman information based on band intensity ratios from the AWG channels is also preserved compared with the spectral integration of bands, with a maximum relative error of 9% attributed to some light that might have leaked from the channels to the device substrate. These results are a step towards the realization of a technology suitable for dedicated, low‐cost, miniaturized Raman devices. Copyright © 2012 John Wiley & Sons, Ltd.
The dependency of private entrepreneurs on the Chinese state
Authors: Yang Keming
Published: May 2012

Despite the introduction of market mechanisms and the rapid growth of the private sector, in some ways important to the entrepreneurial process, private entrepreneurs in China remain dependent on the Chinese state.
The internationalization process of Chinese SMEs: does globalizing wholesale markets play a role?
Authors: Wang Jinmin , Ngoasong Michael Z.
Published: May 2012

The globalization of the wholesale market is likely to accelerate the pace of export‐oriented internationalization of labor‐intensive SMEs in East China.
Performing Culture at the Formosan Aboriginal Culture Village in Taiwan: Exploring Performers' Subjectivities Using Q Method
Authors: Hunter William Cannon
Published: May 2012

In less than two decades, Taiwan indigenous culture has moved from obscurity to a central feature of the national image. Culture performances have become a popular attraction in the country, especially at culture parks. This paper explores how culture performers at the Formosan Aboriginal Culture Village in Taiwan view their work. A demonstration of Q method is used with a P set of 30 respondents and a Q set of 42 statements. Respondents express their subjectivity toward culture performance. It was found that respondents believe that performing indigenous culture is a cultural experience rather than provision of a service commodity. Copyright © 2012 John Wiley & Sons, Ltd.
“Nothing really matters”: Emotional numbing as a link between trauma exposure and callousness in delinquent youth
Authors: Kerig Patricia K. , Bennett Diana C. , Thompson Mamie , Becker Stephen P.
Published: May 2012

This study investigated the interrelations among trauma exposure, emotional numbing, and callous–unemotional traits in a sample of 276 youth (68 girls and 208 boys) recruited from 2 juvenile detention centers. Youth completed interview measures of trauma exposure and betrayal trauma, as well as self‐report measures of emotional numbing and callous–unemotional traits. Results of path analyses using nonparametric bootstrapping procedures indicated findings consistent with the hypothesis that the association between trauma exposure and callous–unemotional traits was mediated by the general numbing of emotions, R2 = .40, and also specifically by numbing of sadness, R2 = .27. In addition, further analyses indicated that numbing of fear, R2 = .18, and sadness, R2 = .26, statistically mediated the relations to callous–unemotional traits only for those traumatic experiences involving betrayal. Gender was not found to moderate these effects.
Evaluating the ability of regional models to predict local avian abundance
Authors: LeBrun Jaymi J. , Thogmartin Wayne E. , Miller James R.
Published: May 2012

Spatial modeling over broad scales can potentially direct conservation efforts to areas with high species‐specific abundances. We examined the performance of regional models for predicting bird abundance at spatial scales typically addressed in conservation planning. Specifically, we used point count data on wood thrush (Hylocichla mustelina) and blue‐winged warbler (Vermivora cyanoptera) from 2 time periods (1995–1998 and 2006–2007) to evaluate the ability of regional models derived via Bayesian hierarchical techniques to predict bird abundance. We developed models for each species within Bird Conservation Region (BCR) 23 in the upper midwestern United States at 800‐ha, 8,000‐ha, and approximately 80,000‐ha scales. We obtained count data from the Breeding Bird Survey and land cover data from the National Land Cover Dataset (1992). We evaluated predictions from the best models, as defined by an information‐theoretic criterion, using point count data collected within an ecological subregion of BCR 23 at 131 count stations in the 1990s and again in 2006–2007. Competing (Deviance Information Criteria <5) blue‐winged warbler models accounted for 67% of the variability and suggested positive associations with forest edge and proportion of forest at the 8,000‐ha scale, and negative associations with forest patch area (800 ha) and wetness (800 ha and 80,000 ha). The regional model performed best for blue‐winged warbler predicted abundances from point counts conducted in Iowa during 1995–1996 (rs = 0.57; P = 0.14), the survey period that most closely aligned with the time period of data used for regional model construction. Wood thrush models exhibited positive correlations with point count data for all survey areas and years combined (rs = 0.58, P ≤ 0.001). In comparison, blue‐winged warbler models performed worse as time increased between the point count surveys and vintage of the model building data (rs = 0.03, P = 0.92 for Iowa and rs = 0.13, P = 0.51 for all areas, 2006–2007), likely related to the ephemeral nature of their preferred early successional habitat. Species abundance and sensitivity to changing habitat conditions seems to be an important factor in determining the predictive ability of regional models. Hierarchical models can be a useful tool for concentrating efforts at the scale of management units and should be one of many tools used by land managers, but we caution that the utility of such models may decrease over time for species preferring relatively ephemeral habitats if model inputs are not updated accordingly. © 2012 The Wildlife Society.
Habitat associations of California ground squirrels and Botta's pocket gophers on levees in California
Authors: Ordeñana Miguel A. , Van Vuren Dirk H. , Draper John P.
Published: May 2012

Vegetation management on levees, especially removal of trees and shrubs, might affect burrowing mammals that are considered threats to levee integrity. We evaluated habitat associations of California ground squirrels (Otospermophilus beecheyi) and Botta's pocket gophers (Thomomys bottae) on levees in the Sacramento Valley to assess the effects of levee vegetation management on these species. Using burrows as an indirect measure of mammal presence, we found that the presence of trees had a negative effect on the occurrence and abundance of ground squirrels on levees, and on the location of their burrowing activities on the levee slope, potentially because visual occlusion caused by tall woody vegetation impedes detection of predators. Similarly, trees had a negative effect on the abundance of pocket gophers on levees and on the location of their burrowing activities on the levee slope, probably because of the effect of tree cover on food availability. The conversion of woodland habitats to grasslands on levees most likely will result in increased occurrence, abundance, or both of ground squirrels and pocket gophers, and thereby increase the potential threat that their burrowing activities pose to levee integrity. © 2012 The Wildlife Society.
Analyzing Employee Agreement on Maturity Assessment Tools for Organizations
Authors: Willems Jurgen , den Bergh Joachim Van , Deschoolmeester Dirk
Published: May 2012

The objective of this paper is to investigate the impact that individual raters have on maturity assessments of organizations in the particular context of business process management (BPM). The hypotheses tested relate to the extent of the impact of individuals on maturity score variances and with the enforcing effect of organizational size on the disagreement among employees within organizations. Eight multilevel random‐effects analyses for eight separate maturity dimensions clarify the intra‐class correlation (agreement) within organizations. The analyses are based on a data set with a strictly hierarchical two‐level data structure of employees (1755) nested within organizations (61). Results show that variance within organizations is significantly larger than zero and is even more important than variance between organizations. We conclude that a large individual background effect exists when rating an organization's business process maturity. In addition, we find that the larger the organizations are, the more disagreement within organizations is visible. Copyright © 2012 John Wiley & Sons, Ltd.
Applicability of ring‐on‐disc and pin‐on‐plate test methods for Cu–steel and Al–steel systems for large area conformal contacts
Authors: Pondicherry Kartik S. , Grün Florian , Gódor István , Bertram Rich , Offenbecher Martin
Published: May 2012

This study compares two methods for model scale testing of ferrous/non‐ferrous tribocouples under large area conformal contact condition, the kind existing in engine components such as journal bearings. Results show that the ring‐on‐disc method is better suited to visualise the performance of such tribosystems compared with the pin‐on‐plate method. The former offers greater sensitivity to minor changes in coefficient of friction and contact potential and is able to determine the thermal stability of the tribosystem under given conditions. Post‐test surface characterisation revealed protective phosphorus‐rich tribofilms on the surface of the steel counterparts from both test methods. Copyright © 2012 John Wiley & Sons, Ltd.
Fluorescence Micropatterning by the Photo‐Anilide Rearrangement of Polymer Bearing Anilide Groups
Authors: Chae Kyu Ho , Baek Sun Jung
Published: May 2012

A fluorescent micropattern in a thin polymer film is fabricated via a photo‐anilide rearrangement of anilide groups in the polymer. Polymer bearing anilide groups are prepared by polymerization of N‐phenyl methacrylamide (PMA) and methyl methacrylate. The photo‐anilide rearrangement of the prepared polymer and the reaction of the produced amino groups with fluorescamine, are studied by using UV and IR absorption spectroscopy. The fluorescence spectrum of the fluorescamine‐treated irradiated polymer film shows a strong fluorescence in the range of ≈420–620 nm with a fluorescence maximum at 496 nm. The patterns exhibited very distinct fluorescence images in the colors of dark blue, sky blue, green, yellow, and red depending on the observed wavelength ranges.
Size‐Tunable Polymeric Nanoreactors for One‐Pot Synthesis and Encapsulation of Quantum Dots
Authors: Qian Guannan , Zhu Benchuan , Wang Youfu , Deng Sheng , Hu Aiguo
Published: May 2012

Hydrophilic polymeric nanoparticles are synthesized through a Bergman cyclization‐ mediated intramolecular chain collapse of structurally well‐defined linear polymers, and then used as size‐tunable nanoreactors to fabricate and encapsulate quantum dots in a one‐pot reaction. Crystalline quantum dots are formed in all of these nanoreactors and visualized by transmission electron microscopy. Smaller nanoreactors produce one quantum dot each while larger nanoreactors form a number, resulting in fluorescence quenching. By controlling the molecular weight of the linear polymer precursor, a variable number of nanocrystals are fabricated and assembled in a single nanoreactor.
Liraglutide withdrawal rates: ‘real world’ practice
Authors: Balasanthiran A , Munro N , Watters K , Poots AJ , Morganstein D , Feher MD
Published: May 2012

Important side effects and potential clinical hazards have emerged from long‐term follow up in some drug classes used in type 2 diabetes treatment. Systematic phase 4 post‐marketing data in early use of newer diabetes drugs may have a role in informing drug choice in practice and assist in pharmacoeconomic assessments of these drug choices.

We carried out a comparison of the prevalence of drug withdrawals derived from both liraglutide registration trial data, and a systematic, prospective case‐note review of all new liraglutide prescriptions (n=176) from a specialist diabetes clinic over the first 12 months of drug introduction.

Trial data used for the marketing authorisation application for liraglutide reported 7.0% withdrawal due to adverse events. Equal numbers of patients experienced mild, moderate and severe side effects. By contrast, data derived from a ‘real world’ clinical group describe 14.8% withdrawal due to adverse events, with withdrawal typically occurring early, by three months. Adverse events were more frequently responsible for treatment withdrawal at lower, compared to higher, doses of liraglutide therapy.

Systematic observations of withdrawals in early use of new drugs in current clinical practice are higher than reported in registration trial data. These data highlight that post‐marketing surveillance should inform guideline recommendations and pharmacoeconomic evaluations. Copyright © 2012 John Wiley & Sons.
Biodegradable aromatic copolyesters made from bicyclic acetalized galactaric acid
Authors: Lavilla C. , Alla A. , Martínez de Ilarduya A. , Benito E. , García‐Martín M.G. , Galbis J.A. , Muñoz‐Guerra S.
Published: May 2012

Random poly(hexamethylene terephthalate‐co‐galactarate)s and poly(dodecamethylene terephthalate‐co‐galactarate)s copolyesters covering the whole range of compositions were obtained with weight‐average molecular weights of ∼30,000–50,000 g mol−1 by melt polycondensation. They were thermally stable above 300 °C, and displayed Tg in the +20 to −20 °C range with values steadily decreasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 50 and 150 °C and those made from dodecanediol were able to crystallize from the melt at a crystallization rate depending on composition. Copolyesters containing up to 50% of galactaric units retained the crystal structure of their respective polyterephthalate homopolyesters, whereas they adopted the structure of the respective polygalactarates when the content in Galx units reached 70%. Stress‐strain essays revealed decay in the mechanical parameters as the aromatic units were replaced by Galx. Incubation in aqueous buffer revealed that hydrolysis of the polyesters were largely enhanced by copolymerization and evidenced the capacity of the Galx unit for making aromatic polyesters susceptible to biodegradation. A detailed NMR analysis complemented by SEM observations indicated that hydrolysis took place by preferred splitting of galactarate ester bonds with releasing of alkanediol and Galx‐diacid. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of novel oligoester‐block‐polyacrylate‐block‐oligoester ABA triblock copolymers by coupling methods
Authors: Liénafa Livie , Monge Sophie , Robin Jean‐Jacques
Published: May 2012

An original approach based on coupling methodology was used to prepare novel well‐defined ABA triblock copolymers, made of polyester‐type chain ends (A) associated with a polyacrylate midblock (B). Poly(ethylene terephthalate)‐block‐poly(lauryl acrylate)‐block‐poly(ethylene terephthalate) (PET‐b‐PLAc‐b‐PET) copolymers were achieved from poly(ethylene terephthalate)‐b‐poly(lauryl acrylate) (PET‐b‐PLAc) diblock ones. The first step consisted in the synthesis of diblock copolymers by atom transfer radical polymerization of lauryl acrylate starting from PET segment as a macroinitiator. In the second step, the coupling of diblock copolymers was achieved using four different methods, which were evaluated and compared: atom transfer radical coupling, “click” chemistry using the Huisgen's reaction, and coupling via a dithiol reagent or a diisocyanate molecule. Coupling using the Huisgen's reaction or a diisocyanate spacer proved to be the most efficient techniques. Even if these methods showed limitation and were only adapted for copolymers with low molecular weights, we managed to successfully prepare ABA triblock copolymers involving a polyester segment as end blocks and a polyacrylate moiety as midblock. To our knowledge, such kind of chemical structure has never been reported before and would be useful, possibly affording physical networks leading to rheological modification, for instance. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Surface nanostructuring of kevlar fibers by atmospheric pressure plasma‐induced graft polymerization for multifunctional protective clothing
Authors: Widodo Mohamad , El‐Shafei Ahmed , Hauser Peter J.
Published: May 2012

Atmospheric plasma‐induced graft polymerization was employed successfully to generate free radical on the surface of Kevlar® (poly‐(p‐phenylene terephthalamide or PPTA), and to initiate and control graft polymerization of cationic antimicrobial precursors diallyldimethylammonium chloride (DADMAC) or 3‐(trimethoxysilyl)propyl‐dimethyloctadecyl ammonium chloride (TMS) onto the fabric surface, which eliminates the need for separate processes that may involve thermal energy or UV irradiation. It was demonstrated that when the radiofrequency of the plasma power was 400 W, the radical density generated on the surface was 1015 to 1016 radicals cm−2, which were enough to generate a poly‐DADMAC or poly‐TMS with surface charge of at least 2 × 1017 N+/cm2, which is the minimum threshold for an effective cationic biocidal surface. In both cases, the grafted polymers were characterized and confirmed using SEM, FTIR, and XPS. The antimicrobial activity was measured using the AATCC Test Method 100, which showed that at least 3‐log reduction of bacteria colonies was achieved in the case of grafted poly‐DADMAC or grafted poly‐TMS on Kevlar®. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Carrier dynamics and efficiency droop in AlGaN epilayers with different Al content
Authors: Tamulaitis Gintautas , Mickevičius Jūras , Dobrovolskas Darius , Kuokštis Edmundas , Shur Michael S. , Shatalov Max , Yang Jinwei , Gaska Remis
Published: May 2012

Carrier dynamics and emission efficiency droop in AlGaN epilayers containing different Al content were studied under pulsed (30 ps) and quasi‐steady‐state photoexcitation. Samples with Al content ranging from 17% to 50% but having similar carrier lifetimes (50‐80 ps) were selected for the study. Considerable heating of nonequilibrium carriers at room temperature was observed. Carrier redistribution down to deeper localized states is demonstrated. It is shown that the temperature decay is faster than the decay of localized carriers, which determine the photoluminescence decay kinetics at later stages of the decay. The efficiency droop onsets at lower excitation power densities in the samples with higher Al content presumably having higher density of nonradiative recombination centers and higher density of localized states. The results are in favour of the assumption that the droop in these epilayers is caused by saturation of the localized states and hopping of less localized carriers to the centers of nonradiative recombination. The effect might be enhanced by carrier heating (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure and optical anisotropy of InGaAs quantum rods studied by photoreflectance and photoluminescence
Authors: Nedzinskas Ramūnas , Čechavičius Bronislovas , Česnauskas Audrius , Kavaliauskas Julius , Karpus Vytautas , Valušis Gintaras , Li Lianhe , Khanna Suraj P. , Linfield Edmund H.
Published: May 2012

Self‐assembling nanostructures comprising InGaAs quantum rods (QRs) immersed into 2‐dimensional InGaAs layer (QW) were examined by photoreflectance (PR) and photoluminescence (PL) spectroscopy techniques. Spectral features associated with interband op‐ tical transitions occurring in the QR and the surrounding QW regions have been identified. The polarized PR and PL studies revealed a high in‐plane optical anisotropy of ≈60% for QR‐related optical transitions.

We have clearly observed that both the QR‐ and the QW‐related transition energies, and PL intensities are sensitive to the As source (As2 or As4) used in molecular beam epitaxy growth of the nanostructures. The changes in optical response are mainly attributed to carrier confinement effects caused by variation in indium content within the QR and QW regions. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant optical reflection by periodic systems of the GaAs/AlGaAs quantum well excitons
Authors: Chaldyshev V. V. , Kundelev E. V. , Chen Yuechao , Poddubny A. N. , Vasil'ev A. P. , Liu Zhiheng
Published: May 2012

A periodic multiple quantum well GaAs/AlGaAs structure was designed, grown and characterized in order to reveal resonant features in optical spectra when the Bragg resonance was tuned to the first or second quantum state of the heavy‐hole exciton‐polaritons in the quantum wells. We observed a super‐radiant optical mode formed by the quantum well excitons under double resonance condition, i.e. when the exciton‐polariton and Bragg resonances are met at the same frequency. It is manifested in a strong and wide reflection and electroreflection band (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Repulsive Casimir force between silicon dioxide and superconductor
Authors: Phan Anh D. , Viet N. A.
Published: May 2012

We present a detailed investigation of the Casimir interaction between the superconductor Bi2Sr2CaCu2O8+δ (BSCCO) and silicon dioxide with bromobenzene present in between. We found that the dispersion force is repulsive and the magnitude of the force can be changed by varying the thickness of the object and the temperature. The repulsive force would provide a method to deal with stiction problems and provide much significant from the practical point of view. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radiation coupling with two‐dimensional electron systems in the low limit of the microwave band: magnetoresistance response
Authors: Iñarrea Jesús
Published: May 2012

We report on a theoretical study of radiation‐induced resistance oscillations and zero‐resistance states in two‐dimensional electron systems when the irradiation frequency is very low. In this situation the photon energy is much smaller than the spacing between the Landau levels and therefore interlevel transitions are excluded. Experiments show that when these frequencies are used, resistance oscillations disappear and, instead, a strong suppression of magnetoresistance response is obtained. We apply the radiation‐driven electron orbit model concluding that the resistance suppression is a manifestation of an oscillation of very large wavelength. Under this regime we study the connection with larger frequencies and the dependence on radiation power and temperature. For high enough radiation intensity, we predict that a regime of zero‐resistance states can be reached at these low frequencies, too. The calculated results are in good agreement with experiments. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Supplementation with Curcuminoids on Dyslipidemia in Obese Patients: A Randomized Crossover Trial
Authors: Mohammadi Akram , Sahebkar Amirhossein , Iranshahi Mehrdad , Amini Maral , Khojasteh Roshanak , Ghayour‐Mobarhan Majid , Ferns Gordon A.
Published: May 2012

Dyslipidemia is a leading risk factor for cardiovascular disease and is also a common feature of obesity. Curcumin is a bioactive phytochemical with well‐known antioxidant, anti‐inflammatory, and cardioprotective properties. The present study investigated the hypolipidemic activity of curcumin in obese individuals. Participants (n = 30) were treated with curcuminoids (1 g/day), or placebo in a randomized, double‐blind, placebo‐controlled, crossover trial. Serum concentrations of total cholesterol, triglycerides, low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol, together with anthropometric parameters and high‐sensitivity C‐reactive protein were measured before and after each treatment period. Anthropometric parameters including weight, BMI, waist circumference, hip circumference, arm circumference, and body fat remained statistically unchanged by the end of trial (p > 0.05). As for the lipid profile parameters, serum triglycerides were significantly reduced following curcumin supplementation (p = 0.009). However, curcuminoids were not found to affect serum levels of total cholesterol, low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, and high‐sensitivity C‐reactive protein (p > 0.05). In summary, the findings of the present study indicated that curcuminoid supplementation (1 g/day for 30 days) leads to a significant reduction in serum triglycerides concentrations but do not have a significant influence on other lipid profile parameters as well as body mass index and body fat. Copyright © 2012 John Wiley & Sons, Ltd.
Antipyretic and Anticonvulsant Activity of Polygonatum verticillatum: Comparison of Rhizomes and Aerial Parts
Authors: Khan Haroon , Saeed Muhammad , Gilani Anwarul Hassan , Muhammad Naveed , Haq Ikram‐ul , Ashraf Nadeem , Rehman Najeeb‐ur , Haleemi Ashhad
Published: May 2012

The current study was undertaken to explore the antipyretic and anticonvulsant profile of the Polygonatum verticillatum in established pharmacological paradigms. The crude methanol extract of rhizomes (PR) and aerial parts (PA) of the plant were tested in Brewer's‐yeast‐induced pyrexia and pentylenetetrazole‐induced convulsion test. PR and PA both evoked prominent antipyretic activity (p < 0.01) in a dose‐dependent manner during all assessment times at the dose of 50, 100, and 200 mg/kg intraperitoneally. The protection elicited by PR (82.20%) at 200 mg/kg was comparable with aspirin (88.48%) as a standard drug at 100 mg/kg. However, PA was less potent, and maximum protection was 64% at 200 mg/kg. Both PR and PA were devoid of any anticonvulsant activity. Our results demonstrated prominent evidence of antipyretic activity of P. verticillatum that is consistent with the folk uses of the plant. In addition from a biodiversity point of view, PA of the plant can also be used as an alternate of PR. Copyright © 2012 John Wiley & Sons, Ltd.
Modeling epidemic data diffusion for wireless mobile networks
Authors: Islam Mohammad Towhidul , Akon Mursalin , Abdrabou Atef , Shen Xuemin (Sherman)
Published: May 2012

Data/content dissemination among the mobile devices is the fundamental building block for all the applications in wireless mobile collaborative computing, known as mobile peer‐to‐peer. Different parameters such as node density, scheduling among neighboring nodes, mobility pattern, and node speed have a tremendous impact on data diffusion in a mobile peer‐to‐peer environment. In this paper, we develop analytical models for object diffusion time/delay in a wireless mobile network to apprehend the complex interrelationship among these different parameters. In the analysis, we calculate the probabilities of transmitting a single object from one node to multiple nodes using the epidemic model of spread of disease. We also incorporate the impact of node mobility, radio range, and node density in the networks into the analysis. Utilizing these transition probabilities, we estimate the expected delay for diffusing an object to the entire network both for single object and multiple object scenarios. We then calculate the transmission probabilities of multiple objects among the nodes in the wireless mobile network considering network dynamics. Through extensive simulations, we demonstrate that the proposed scheme is efficient for data diffusion in the wireless mobile network. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis, Characterization and Conductivity of Quaternary Nitrogen Surfactants Modified by the Addition of a Hydroxymethyl Substructure on the Head Group
Authors: Jordan Deborah , Tan Eng , Hegh Dylan
Published: May 2012

Two novel series of hydroxymethyl group‐appended quaternary nitrogen surfactants (QNSs) based on the aliphatic N‐alkyl‐trimethylammonium and aromatic N‐alkylpyridinium head groups were synthesized from the appropriate nitrogen head group precursor and 1‐bromoalkane. The QNSs were characterized using 1H and 13C nuclear magnetic resonance and infrared spectroscopy, and their purity confirmed using elemental analysis. The solution behavior of the QNSs was investigated by conductivity, assessing both the aggregation concentration as well as the amount of counter‐ion dissociation. The results showed a general decrease in the aggregation concentration for the compounds with the hydroxymethyl addition, where the pyridinium compounds were more affected than the ammonium QNSs. In contrast, the extent of counter‐ion dissociation (α) from the aggregate was slightly increased for the ammonium compounds but that of the pyridinium compounds was not generally affected by the structural modification.
Formulation of Canola‐Diesel Microemulsion Fuels and Their Selective Diesel Engine Performance
Authors: Nguyen Thu , Abraham Jacob , Ramallo Melisa , Wagner David , McLennan John
Published: May 2012

Vegetable oils have been considered as an alternative to diesel fuel due to their comparable properties and performance. However, the high viscosity of vegetable oil causes engine durability problems with long‐term usage. Vegetable oil viscosity can be reduced by blending with diesel fuel in thermodynamically stable mixtures using microemulsion fuel formulation techniques. This work focuses on the formulation of microemulsion fuels comprising diesel fuel and canola oil as the oil phase with ethanol and sec‐butanol as viscosity reducers as well as 1‐octanol and oleyl amine as surfactant/cosurfactant. Selective tests on an instrumented diesel engine were performed for formulated microemulsion fuels and No. 2 diesel fuel for comparison. The results show that formulated microemulsion fuels have fuel properties that meet the ASTM requirements for viscosity, cloud point, and pour point for biodiesel. Even more important, they have phase stability over a wide range of temperatures (−10 to 70 °C). Although all of the microemulsion fuels showed higher fuel consumption than diesel fuel, some of the microemulsion fuels had significantly reduced CO and NOx emissions as well as reduced particulates when compared to baseline diesel fuel. The research demonstrates the potential of these microemulsion fuels as alternative to neat diesel fuel.