bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of encapsulation process parameters of calcium alginate beads on Vitamin B12 drug release kinetics
Authors: Abubakr Nada , Jayemanne Amanthi , Audrey Niken , Lin Sean Xuqi , Chen Xiao Dong
Published: October 2009

Calcium alginate beads were prepared by ionotropic gelation of droplet of an alginate solution containing Vitamin B12, followed by oven air drying at 70° C. The beads were characterized by a light microscope and in vitro drug release in phosphate buffer saline (PBS) solution (pH 7.4) maintained at 37° C in order to simulate intestinal fluid conditions. The effect of drug configuration within a bead, various process factors on the bead morphology and drug release properties was investigated. The experimental results indicated that altering the polymer to drug loading ratio, alginate, Vitamin B12 concentration and flow rates affected the Vitamin B12 release rates. The addition of chitosan to the polymer matrix was found to have a significant impact on the rate of release, as it slowed down the release of Vitamin B12. It has also been found that some combinations of the parameters mentioned above, thermal effects in particular, were able to create the clear wall‐core structures, and it is envisaged that one can apply those combinations or at least adopt the overall trend in a more advanced equipment to achieve controlled releasing drug micro‐capsules. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Synthesis, characterization, and thermal degradation kinetics of the copolymer poly(4‐methoxybenzyl methacrylate‐co‐isobornyl methacrylate)
Authors: Kurt Adnan , Kaya Esin
Published: October 2009

A copolymer of 4‐methoxybenzyl methacrylate and isobornyl methacrylate was synthesized by atom transfer radical polymerization. The structure of poly(4‐methoxybenzyl methacrylate‐co‐isobornyl methacrylate) was confirmed by means of Fourier transform infrared, 1H‐NMR, and 13C‐NMR techniques. The molecular weight distribution values of the copolymer were determined with gel permeation chromatography. The number‐average molecular weight and polydispersity index values of poly(4‐methoxybenzyl methacrylate‐co‐isobornyl methacrylate) were found to be 12,500 and 1.5, respectively. The kinetics of the thermal degradation of the copolymer was investigated with thermogravimetric analysis at different heating rates. The activation energy values obtained with the Kissinger, Flynn–Wall–Ozawa, and Tang methods were determined to be 166.38, 167.54, and 167.47 kJ/mol, respectively. Different integral and differential methods were used, and the results were compared with these values. Doyle approximation was also used for comparing the experimental results to master plots. An analysis of the experimental results suggested that the reaction mechanism was an R1 deceleration type in the conversion range studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and flocculation behavior of cationic konjac glucomannan containing quaternary ammonium substituents
Authors: Tian Dating , Wu Xiong , Liu Chengmei , Xie Hong‐Quan
Published: October 2009

A quaternary ammonium derivative of konjac glucomannan (KGM) was prepared by a dry process from KGM and 2,3‐epoxypropyl trimethylammonium chloride. We determined the optimization of the experimental conditions by studying on the effects of the water amount, alkaline catalyst amount, reaction temperature, and reaction time on the degree of substitution. In addition, the flocculation characteristics of the cationic derivative of KGM were evaluated in a 1.0% kaolin suspension with spectrophotometry via investigation of the influence of the flocculant amount, pH, salt concentration, temperature, and settling time on the flocculation. The results show that the synthesized cationic KGM could potentially be used as a high‐performance flocculating agent. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of the rubber crosslinking density of a core–shell structure modifier on the properties of toughened poly(methyl methacrylate)
Authors: Gui Y. , Sun S. L. , Han Y. , Zhang H. X. , Zhang B. Y.
Published: October 2009

Four kinds of core–shell structure acrylic impact modifiers (AIMs) with different rubber crosslinking densities were synthesized. The effects of the rubber crosslinking density of the AIMs on the crack initiation and propagation resistance and the mechanical properties of the AIM/poly(methyl methacrylate) (PMMA) blends were investigated, and we found that the maximum stress intensity factor, crack propagation energy, and Izod impact strength reached maximums when the appropriate rubber crosslinking density of AIM, 2.51 × 1025 crosslinks/m3, was adopted. Transmission electron microscopy photographs of the AIM/PMMA blends showed that the AIMs dispersed uniformly in the PMMA matrix. Meanwhile, through the analysis of optical photos and scanning electron microscopy of the impact fracture surface, we found that the deformation mechanism of the AIM/PMMA blends was local matrix shear yielding initiated by rubber particle cavitation of the AIM. The rubber of the AIM, whose crosslinking density was 2.51 × 1025 crosslinks/m3, was beneficial to the formation of intensive voids and initiated the local shear yielding of nearby modifiers of the PMMA matrix effectively in impact tests, which led to higher Izod impact strengths. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Partial replacement of NR by GTR in thermoplastic elastomer based on LLDPE/NR through using reactive blending: Its effects on morphology, rheological, and mechanical properties
Authors: Rezaei Abadchi Majid , Jalali Arani Azam , Nazockdast Hossien
Published: October 2009

Attempts have been made to use different amount of ground tire rubber (GTR) powder as a partial substitute for natural rubber (NR) in thermoplastic elastomer based on linear low‐density polyethylene (LLDPE, 60 wt%) and NR (40wt%). Maleic anhydride (MA) and dicumyl peroxide (DCP) were used, during melt mixing of the compound, to modify GTR and vulcanize the rubber phases of the blends. Morphology of the blends was studied by scanning electron microscopy and rheological behavior investigated through rheomechanical spectroscopy. Mechanical properties of the blends were also measured, and the effect of GTR concentration on properties was evaluated. Obtained results showed that modification of GTR with MA and using DCP in the blends containing GTR improves the bonding between GTR and matrix. This leads to a distinctive rheological behavior and enhances tensile strength and elongation at break compared to its corresponding simple blend. It can be said that using of MA and DCP during melt mixing of thermoplastic elastomers based on LLDPE/NR containing GTR, concludes to a better dispersion of GTR and formation of morphology similar to that of a dynamic vulcanized thermoplastic elastomer, which improves interfacial bonding between phases and causes a dramatically increase in mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Anticonvulsant profile and teratogenic evaluation of potent new analogues of a valproic acid urea derivative in NMRI mice
Authors: Okada Akinobu , Noyori Hiroko , Yagen Boris , Shimshoni Jakob Avi , Bialer Meir , Fujiwara Michio
Published: October 2009

BACKGROUND: Valproic acid (VPA) is used to treat epilepsy and bipolar disorders, as well as for migraine prophylaxis. However, its clinical use is limited by two life‐threatening side effects: hepatotoxicity and teratogenicity. To develop a more potent and safer second‐generation VPA drug, the urea derivatives of four VPA analogs (2‐ethyl‐3‐methylpentanoyl urea, 2‐ethylhexanoyl urea, 2‐ethyl‐4‐methylpentanoyl urea, and 2‐methylbutanoyl urea) were synthesized. METHODS: Four CNS‐active analogs of a VPA urea derivative testedthe anticonvulsant activity in the maximal electroshock seizure test (MES) and subcutaneous metrazol seizure threshold test (scMet). Teratogenic effects of these compounds were evaluated in NMRI mice susceptible to VPA‐induced teratogenicity by comparison with VPA. RESULTS: All four VPA analogs showed superior anticonvulsant activity over VPA. Compared with VPA, which induced neural tube defects (NTDs) in fetuses at 1.8 and 3.6 mmol/kg, the analog derivatives induced no NTDs at any concentration up to 4.8 mmol/kg (except for a single abnormality at 3.6 mmol/kg with 2‐ethyl‐3‐methylpentanoyl urea). Skeletal examination also revealed that the acylurea derivatives induced vertebral and rib abnormalities in fetuses markedly less frequently than VPA. Our results confirmed that the analogue derivatives are significantly less teratogenic than VPA in NMRI mice. CONCLUSIONS: The CNS‐active VPA analogs containing a urea moiety, which have better anticonvulsant potency and lack teratogenicity, are good potential candidates as second‐generation VPA antiepileptic drugs. Birth Defects Res (Part B) 86:394–401, 2009. © 2009 Wiley‐Liss, Inc.
Determination of rutin by flow injection chemiluminescence method using the reaction of luminol and potassium hexacyanoferrate(III) with the aid of response surface methodology
Authors: Yang Dan , Li Haiyun , Li Ziyuan , Hao Zaibin , Li Jianping
Published: October 2009

A novel flow injection chemiluminescence (CL) method for the determination of rutin was reported. The proposed method was based on the enhanced effect of rutin on the chemiluminescence intensity of luminol and potassium hexacyanoferrate(III) reaction in NaOH medium. The variables of reaction system, such as luminol concentration, potassium hexacyanoferrate(III) concentration and NaOH concentration, were optimized with the aid of response surface methodology. For the responses prediction, a second‐order polynomial model (SOPM) was applied. The optimal conditions for determination of rutin estimated by the model equation were as follows: NaOH concentration of 0.13 mol/L luminol concentration of 0.94 × 10−6 mol/L, and K3Fe(CN)6 concentration of 1.09 × 10−4 mol/L. The theoretical increased ratio of CL intensity (IRI) predicted and actual IRI for 0.05 mg/L rutin under the above conditions were 99.40 and 99.74%, respectively. The SOPM model proved to be powerful for navigating the design space. Under the above optimum conditions, the increased IRI was linearly related to the concentration of rutin in the range from 0.008 to 0.100 mg/L with the regression equation IRI = 1948.20c + 5.24 (r = 0.9994) and in the range from 0.100 to 1.000 mg/L with the regression equation IRI = 1362.50 c + 61.94 (r = 0.9996). The detection limit (3σ) was of 1.95 × 10−3 mg/L. The sampling frequency of this method was 72/h. The method was used directly to determine rutin in tablets. Copyright © 2009 John Wiley & Sons, Ltd.
Practical application of synthetic biology principles
Authors: Marner Wesley D.
Published: October 2009

Synthetic biology can be defined as the “repurposing and redesign of biological systems for novel purposes or applications, ” and the field lies at the interface of several biological research areas. This broad definition can be taken to include a variety of investigative endeavors, and successful design of new biological paradigms requires integration of many scientific disciplines including (but not limited to) protein engineering, metabolic engineering, genomics, structural biology, chemical biology, systems biology, and bioinformatics. This review focuses on recent applications of synthetic biology principles in three areas: (i) the construction of artificial biomolecules and biomaterials; (ii) the synthesis of both fine and bulk chemicals (including biofuels); and (iii) the construction of “smart” biological systems that respond to the surrounding environment.
Initial loss but later excess of GABAergic synapses with dentate granule cells in a rat model of temporal lobe epilepsy
Authors: Thind Khushdev K. , Yamawaki Ruth , Phanwar Ibanri , Zhang Guofeng , Wen Xiling , Buckmaster Paul S.
Published: October 2009

Many patients with temporal lobe epilepsy display neuron loss in the dentate gyrus. One potential epileptogenic mechanism is loss of GABAergic interneurons and inhibitory synapses with granule cells. Stereological techniques were used to estimate numbers of gephyrin‐positive punctae in the dentate gyrus, which were reduced short‐term (5 days after pilocarpine‐induced status epilepticus) but later rebounded beyond controls in epileptic rats. Stereological techniques were used to estimate numbers of synapses in electron micrographs of serial sections processed for postembedding GABA‐immunoreactivity. Adjacent sections were used to estimate numbers of granule cells and glutamic acid decarboxylase‐positive neurons per dentate gyrus. GABAergic neurons were reduced to 70% of control levels short‐term, where they remained in epileptic rats. Integrating synapse and cell counts yielded average numbers of GABAergic synapses per granule cell, which decreased short‐term and rebounded in epileptic animals beyond control levels. Axo‐shaft and axo‐spinous GABAergic synapse numbers in the outer molecular layer changed most. These findings suggest interneuron loss initially reduces numbers of GABAergic synapses with granule cells, but later, synaptogenesis by surviving interneurons overshoots control levels. In contrast, the average number of excitatory synapses per granule cell decreased short‐term but recovered only toward control levels, although in epileptic rats excitatory synapses in the inner molecular layer were larger than in controls. These findings reveal a relative excess of GABAergic synapses and suggest that reports of reduced functional inhibitory synaptic input to granule cells in epilepsy might be attributable not to fewer but instead to abundant but dysfunctional GABAergic synapses. J. Comp. Neurol. 518:647–667, 2010. © 2009 Wiley‐Liss, Inc.
A novel model of retinal ablation demonstrates that the extent of rod cell death regulates the origin of the regenerated zebrafish rod photoreceptors
Authors: Montgomery Jacob E. , Parsons Michael J. , Hyde David R.
Published: October 2009

The adult zebrafish retina continuously produces rod photoreceptors from infrequent Müller glial cell division, yielding neuronal progenitor cells that migrate to the outer nuclear layer and become rod precursor cells that are committed to differentiate into rods. Retinal damage models suggested that rod cell death induces regeneration from rod precursor cells, whereas loss of any other retinal neurons activates Müller glia proliferation to produce pluripotent neuronal progenitors that can generate any other neuronal cell type in the retina. We tested this hypothesis by creating two transgenic lines that expressed the E. coli nitroreductase enzyme fused to EGFP (NTR‐EGFP) in only rods. Treating transgenic adults with metronidazole resulted in two rod cell death models. First, killing all rods throughout the Tg(zop:nfsB‐EGFP)nt19 retina induced robust Müller glial proliferation, which yielded clusters of neuronal progenitor cells. In contrast, ablating only a subset of rods across the Tg(zop:nfsB‐EGFP)nt20 retina led to rod precursor, but not Müller glial, cell proliferation. We propose that two different criteria determine whether rod cell death will induce a regenerative response from the Müller glia rather than from the resident rod precursor cells in the ONL. First, there must be a large amount of rod cell death to initiate Müller glia proliferation. Second, the rod cell death must be acute, rather than chronic, to stimulate regeneration from the Müller glia. This suggests that the zebrafish retina possesses mechanisms to quantify the amount and timing of rod cell death. J. Comp. Neurol. 518:800–814, 2010. © 2009 Wiley‐Liss, Inc.
The cortistatin gene PSS2 rather than the somatostatin gene PSS1 is strongly expressed in developing avian autonomic neurons
Authors: Nishi Rae , Stubbusch Jutta , Hulce Jonathan J. , Hruska Martin , Pappas Anthony , Bravo Maria‐Christina , Huber Leslie P. , Bakondi Benjamin , Soltys John , Rohrer Hermann
Published: October 2009

Somatostatin and cortistatin are neuromodulators with divergent expression patterns and biological roles. Whereas expression and function of genes encoding somatostatin (PSS1) and the related peptide cortistatin (PSS2) have been studied in detail for the central nervous system (CNS) and immune system, relatively little is known about their expression patterns in the peripheral nervous system (PNS). We compare the expression patterns of PSS1 and PSS2 in chicken embryos. At E14, PSS1 is higher in the CNS versus PNS, whereas PSS2 is higher in the PNS. During early development, PSS1 is transiently expressed in lumbar sympathetic ganglia and is detectable at low levels throughout the development of dorsal root and ciliary ganglia. In contrast, PSS2 expression increases as development progresses in sympathetic and dorsal root ganglia, whereas levels in ciliary ganglia by E8 are more than 100‐fold higher than in sympathetic ganglia. Activin, which induces somatostatin‐like immunoreactivity in ciliary ganglion neurons in vivo and in vitro, controls PSS2 expression by stabilizing PSS2 but not PSS1 mRNA. We conclude that much of the somatostatin‐like immunoreactivity in the developing avian peripheral nervous system is actually cortistatin, the PSS2 product, as opposed to true somatostatin, which is the PSS1 product. The identification of PSS2 as the predominantly expressed somatostatin gene family member in avian autonomic neurons provides a molecular basis for further functional and pharmacological studies. J. Comp. Neurol. 518:839–850, 2010. © 2009 Wiley‐Liss, Inc.
Adsorption Mechanism of Polypeptides and Their Location at Hydrophobic Interfaces
Authors: Pirzer Tobias , Hugel Thorsten
Published: October 2009

The adhesion of polypeptides and proteins at interfaces is important for a wide variety of systems—from the adhesion onto vessels during their production process over functional coatings to protein–membrane interactions in single cells. Herein, we apply an atomic‐force‐microscopy‐based single‐molecule method and poly‐D‐tyrosine to determine the adhesion strength and location of polypeptides at interfaces. Surprisingly, the support (solid, liquid or gas) hardly influences the adhesion in an aqueous environment, while the addition of ethanol to the solvent cuts the adhesion in half. These findings allow us to propose that the adsorbed polypeptide spans over both the depletion layer and the hydrophobic hydration layer to facilitate a compensation mechanism between dispersive and hydration forces.
Phase‐Transition‐ and Dissipation‐Driven Budding in Lipid Vesicles
Authors: Franke Thomas , Leirer Christian T. , Wixforth Achim , Dan Nily , Schneider Matthias F.
Published: October 2009

Membrane budding has been extensively studied as an equilibrium process attributed to the formation of coexisting domains or changes in the vesicle area‐to‐volume ratio (reduced volume). In contrast, non‐equilibrium budding remains experimentally widely unexplored, especially when timescales fall well below the characteristic diffusion time of lipids, ${\tau }$. We show that localized mechanical perturbations, initiated by driving giant unilamellar vesicles (GUVs) through their lipid main phase transition from the gel to the fluid phase, lead to the immediate formation of rapidly growing, localized, non‐equilibrium buds when the transition takes place at short timescales (<${\tau }$). We show that these buds arise from small fluidlike perturbations and grow as spherical caps in the third dimension, since in‐plane spreading is obstructed by the continuous rigid gel‐like matrix. Accounting for membrane and bulk viscosity, we demonstrate that dissipation favors the formation of multiple buds which decrease in size with increasing bulk viscosity. Above a certain critical rate of area change, which we experimentally control by the change in temperature, the dissipative contribution to the total energy of the system exceeds the elastic contributions and multiple budding is expected. This rate depends on membrane and media viscosity and is correctly predicted, in order of magnitude, by our theoretical description.
Theoretical analysis of iterative signal reconstruction for impulsive noise mitigation in OFDM systems
Authors: Rozic Nikola , Radic Josko
Published: October 2009

In this paper a theoretical analysis of the iterative signal reconstruction algorithm for impulsive noise mitigation in orthogonal frequency‐division multiplexing (OFDM) systems is developed. The following main results are developed: first, analytical model for the total noise in the frequency domain, and second the model for the total noise probability density function (pdf) in the frequency domain, both defined for each step of the iterative reconstruction process. Finally, based on the pdf of the total noise, explicit expressions for BER inkth iteration are defined as well. The main intention of the paper is to present the approach to theoretical analysis of the iterative impulsive noise mitigation algorithm that has not yet been appeared in the literature, because the theoretical analysis of the noise pdf during iterations has been considered as too complex a problem. Analyses and analytical results presented in the paper are given for scenario with a fixed number of noise impulses per frame. However, this is not a handicap of the proposed approach, since all presented models can be used as building blocks for scenarios with other impulsive noise distributions including Bernoulli–Gaussian and Middleton's Class A. Copyright © 2009 John Wiley & Sons, Ltd.
Utility‐based resource allocation in uplink of OFDMA‐based cognitive radio networks
Authors: Lu Qianxi , Peng Tao , Wang Wei , Wang Wenbo , Hu Chao
Published: October 2009

Cognitive radio makes it possible for an unlicensed user to access a spectrum opportunistically on the basis of non‐interfering to licensed users. This paper addresses the problem of resource allocation for multiaccess channel (MAC) of OFDMA‐based cognitive radio networks. The objective is to maximize the system utility, which is used as an approach to balance the efficiency and fairness of wireless resource allocation. First, a theoretical framework is provided, where necessary and sufficient conditions for utility‐based optimal subcarrier assignment and power allocation are presented under certain constraints. Second, based on the theoretical framework, effective algorithms are devised for more practical conditions, including ellipsoid method for Lagrangian multipliers iteration and Frank–Wolfe method for marginal utilities iteration. Third, it is shown that the proposed scheme does not have to track the instantaneous channel state via an outage‐probability‐based solution. In the end, numerical results have confirmed that the utility‐based resource allocation can achieve the optimal system performance and guarantee fairness. Copyright © 2009 John Wiley & Sons, Ltd.
Generation of aggrecan‐CreERT2 knockin mice for inducible Cre activity in adult cartilage
Authors: Henry Stephen P. , Jang Chuan‐Wei , Deng Jian Min , Zhang Zhaoping , Behringer Richard R. , de Crombrugghe Benoit
Published: October 2009

The function of cartilage in the adult is dependent on a host of regulatory molecules such as growth factors, extracellular matrix, enzymes, signaling molecules, and transcription factors. However, germline mutations in some genes that are expressed in adult cartilage lead to embryonic or perinatal lethality. To examine the function of these and other genes postnatally, we have generated a targeted mouse by homologous recombination that “knocks in” the inducible Cre recombinase construct, CreERT2, in the 3′ untranslated region of the endogenous mouse aggrecan gene (Agc1tm(IRES‐creERT2)). The properties and efficiency of the inducible cre recombinase were tested by examining X‐gal staining of tissues from embryos as well as growing and adult Agc1tm(IRES‐creERT2)/+;Rosa 26R mice. These mice were injected with the inducer, tamoxifen, at different time points during embryonic development and postnatally up to 6 months of age. Strong X‐gal staining was observed in growth plate and articular cartilage as well as the fibrocartilage of meniscus, trachea, and intervertebral discs reproducing the pattern of endogenous aggrecan gene expression. In conclusion, we have generated a mouse model in which genes implicated in cartilage degenerative diseases can be inactivated in a spatial and temporal fashion in postnatal and adult mice. genesis 47:805–814, 2009. © 2009 Wiley‐Liss, Inc.
Cre activity in fetal albCre mouse hepatocytes: Utility for developmental studies
Authors: Weisend Carla M. , Kundert Jean A. , Suvorova Elena S. , Prigge Justin R. , Schmidt Edward E.
Published: October 2009

The albCre transgene, having Cre recombinase driven by the serum albumin (alb) gene promoter, is commonly used to generate adult mice having reliable hepatocyte‐specific recombination of loxP‐flanked (“floxed”) alleles. Based on previous studies, it has been unclear whether albCre transgenes are also reliable in fetal and juvenile mice. Perinatal liver undergoes a dynamic transition from being predominantly hematopoietic to predominantly hepatic. We evaluated Cre activity during this transition in albCre mice using a sensitive two‐color fluorescent reporter system. From fetal through adult stages, in situ patterns of Cre‐dependent recombination of the reporter closely matched expression of endogenous Alb mRNA or protein, indicating most or all hepatocytes, including those in fetal and juvenile livers, had expressed Cre and recombined the reporter. Our results indicate the albCre transgene is effective in converting simple floxed alleles in fetal and neonatal mice and is an appropriate tool for studies on hepatocyte development. genesis 47:789–792, 2009. © 2009 Wiley‐Liss, Inc.
Developmental regulation of the composite CAG promoter activity in the murine T lymphocyte cell lineage
Authors: Baup Delphine , Moser Muriel , Schurmans Stéphane , Leo Oberdan
Published: October 2009

Promoter selection is of utmost importance for the study of in vivo gene function using transgenic models. In the present study, we have analyzed the expression of the GFP marker under the control of the composite CAG promoter in the lymphoid compartment of several transgenic mouse strains. Despite the ability of the CAG promoter to drive gene expression in almost all tissues examined to date, its activity appears to be developmentally regulated within the T lymphocyte cell lineage. In particular, CD4 and CD8‐expressing, thymic immature T cells displayed lower levels of the GFP marker when compared with both bone marrow precursors and mature circulating T cells, suggesting a transient downregulation of CAG activity during T cell development. Alternative promoters may therefore be preferred for the study of T cell development in vivo using a transgenic approach. genesis 47:799–804, 2009. © 2009 Wiley‐Liss, Inc.
Degradation of ZnO varistors as estimated by aging tests
Authors: Tada Toshiharu
Published: October 2009

Application of voltage during aging tests caused interstitial zinc ions to migrate in the depletion layer and to accumulate on the Schottky barrier, while oxygen ions were evaporated from the layer. Electrons were trapped on the Schottky barrier by the evaporation of the ions, keeping the electric charge neutral in the layer. During no‐voltage periods, interstitial zinc ions that had accumulated were returned to the layer, and oxygen ions were absorbed and returned to it. Trapped electrons were removed by absorption. Thus, the Schottky barrier was changed by the application of a voltage and was restored by removal of the applied voltage, resulting in a change in the resistive leakage current. The evaporated ions were among the released ions, which included oxygen ions dissociated by the continuous operating voltage. The Arrhenius plots used to estimate varistor life crossed each other because the concentrations of interstitial zinc ions and dissociated oxygen ions were lower in the more highly degraded varistors. Thus, it was inferred that cracks occurred in the layer, because ions cannot migrate very well. As a consequence, the resistive leakage current in the more highly degraded varistors was increased because the ZnO grain interfaces were spread by cracks, thus lowering the Schottky barrier. Cracks were caused by dissociated ions which made the Schottky barrier higher and increased stresses, because in the presence of these ions, electrons trapped by evaporation produced a stronger electric field, and oxygen vacancies resulted in a greater positive charge. To prevent cracks, methods based on stress mitigation and reducing oxygen ion migration are suggested. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(2): 1–18, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20934
A role for endobrevin/VAMP8 in CTL lytic granule exocytosis
Authors: Loo Li Shen , Hwang Le‐Ann , Ong Yao Min , Tay Hock Soon , Wang Cheng‐Chun , Hong Wanjin
Published: October 2009

CTL clear virus‐infected cells and tumorigenic cells by releasing potent cytotoxic enzymes stored in preformed lytic granules. The exocytosis process includes polarization of lytic granules toward the immunological synapse, tethering of lytic granules to the plasma membrane and finally fusion of lytic granules with the plasma membrane to release cytotoxic enzymes. Although much is known about the molecular machineries necessary for the earlier steps in lytic granule exocytosis, the molecular machinery governing the final step in the fusion process has not been identified. Here, we show using control and VAMP8 KO mice that VAMP8 is localized to the CTL lytic granules. While the immunological synapse and granule polarization appears normal in both VAMP8 KO and control CTL, CTL‐mediated killing was reduced for the Vamp8–/– CTL. Analysis of lytic enzyme secretion demonstrated that granzyme A and granzyme B secretion is significantly compromised in VAMP8–/– CTL, while the levels of the lytic enzymes in the cells are unaffected. Our results clearly show that VAMP8 is one of the v‐SNARE that regulate the lytic ability of CTL by influencing the ability of the lytic granules to fuse with the plasma membrane and release its contents.
LKB1 is essential for the proliferation of T‐cell progenitors and mature peripheral T cells
Authors: Tamás Peter , Macintyre Andrew , Finlay David , Clarke Rosemary , Feijoo‐Carnero Carmen , Ashworth Alan , Cantrell Doreen
Published: October 2009

The serine/threonine kinase LKB1 has a conserved role in Drosophila and nematodes to co‐ordinate cell metabolism. During T lymphocyte development in the thymus, progenitors need to synchronize increased metabolism with the onset of proliferation and differentiation to ensure that they can meet the energy requirements for development. The present study explores the role of LKB1 in this process and shows that loss of LKB1 prevents thymocyte differentiation and the production of peripheral T lymphocytes. We find that LKB1 is required for several key metabolic processes in T‐cell progenitors. For example, LKB1 controls expression of CD98, a key subunit of the L‐system aa transporter and is also required for the pre‐TCR to induce and sustain the regulated phosphorylation of the ribosomal S6 subunit, a key regulator of protein synthesis. In the absence of LKB1 TCR‐β‐selected thymocytes failed to proliferate and did not survive. LBK1 was also required for survival and proliferation of peripheral T cells. These data thus reveal a conserved and essential role for LKB1 in the proliferative responses of both thymocytes and mature T cells.
Clever‐1/Stabilin‐1 regulates lymphocyte migration within lymphatics and leukocyte entrance to sites of inflammation
Authors: Karikoski Marika , Irjala Heikki , Maksimow Mikael , Miiluniemi Mari , Granfors Kaisa , Hernesniemi Sari , Elima Kati , Moldenhauer Gerhard , Schledzewski Kai , Kzhyshkowska Julia , Goerdt Sergij , Salmi Marko , Jalkanen Sirpa
Published: October 2009

Clever‐1/Stabilin‐1 is a scavenger receptor present on lymphatic and sinusoidal endothelium as well as on a subset of type II macrophages. It is also induced on vasculature at sites of inflammation. However, its in vivo function has remained practically unknown and this work addresses those unknown aspects. We demonstrate using in vivo models that Clever‐1/Stabilin‐1 mediates migration of T and B lymphocytes to the draining lymph nodes in vivo and identify the adhesive epitope of the Clever‐1/Stabilin‐1 molecule responsible for the interaction between lymphocytes and lymphatic endothelium. Moreover, we demonstrate that Ab blocking of Clever‐1/Stabilin‐1 efficiently inhibits peritonitis in mice by decreasing the entrance of granulocytes by 50%, while migration of monocytes and lymphocytes into the inflamed peritoneum is prevented almost completely. Despite efficient anti‐inflammatory activity the Ab therapy does not dramatically dampen immune responses against the bacterial and foreign protein Ag tested and bacterial clearance. These results indicate that anti‐Clever‐1/Stabilin‐1 treatment can target two different arms of the vasculature – traffic via lymphatics and inflamed blood vessels.
Synthesis and Photophysical Properties of 3,8‐Disubstituted 1,10‐Phenanthrolines and Their Ruthenium(II) Complexes
Authors: Karnahl Michael , Krieck Sven , Görls Helmar , Tschierlei Stefanie , Schmitt Michael , Popp Jürgen , Chartrand Daniel , Hanan Garry S. , Groarke Robert , Vos Johannes G. , Rau Sven
Published: October 2009

The palladium‐catalysed cross‐coupling reaction between 3,8‐dibromo‐1,10‐phenanthroline with phenylacetylene or 3,5‐bis(trifluoromethyl)phenylboronic acid gives good yields of the 3,8‐disubstituted products. These 1,10‐phenanthroline derivatives are used for the formation of novel ruthenium complexes of the type [(tbbpy)2Ru(phenR2)]2+ [where tbbpy = 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine, phen = 1,10‐phenanthroline, R represents the substituents at the 3,8 positions with bromine, phenylacetylene or 3,5‐bis(trifluoromethyl)phenyl]. All compounds are completely characterised by NMR and UV/Vis spectroscopy, MS, electrochemical measurements and Raman and resonance Raman spectroscopy. The photophysical properties indicate a strong influence of the substitution of the phenanthroline ligand on the absorption, emission and Raman properties. With resonance Raman spectroscopy the localisation of the singlet metal‐to‐ligand charge‐transfer (1MLCT) excited state is determined. Thesolid‐state structures of 3,8‐dibromo‐1,10‐phenanthroline (phenBr2) and the corresponding ruthenium complex [(tbbpy)2Ru(phenBr2)]2+ and a structural motif of [(tbbpy)2Ru{phen‐3,8‐bis[3,5‐bis(trifluoromethyl)phenyl]}]2+ are also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Mechanofluorochromism of a Series of Benzofuro[2,3‐c]oxazolo[4,5‐a]carbazole‐Type Fluorescent Dyes (Eur. J. Org. Chem. 31/2009)
Authors: Ooyama Yousuke , Kagawa Yusuke , Fukuoka Hiroshi , Ito Genta , Harima Yutaka
Published: October 2009

The cover picture shows “mechanofluorochromism” of a new class of donor‐π‐acceptor‐type fluorescent dyes; a series of benzofuro[2,3‐coxazolo[4,5‐a]carbazole‐type fluorophores show fluorescent color change with a remarkable enhancement in fluorescence quantum yield caused by mechanical stress and reversion to the original fluorescent color by heating or exposure to solvent vapor. Details are discussed in the article by Y. Harima et al. on p. 5321 ff. The background shows the Hiroshima Castle, called the “Carp Castle” in Hiroshima, Japan, which was the castle of the daimyo (feudal lord) of the Hiroshima han (feudal clan), constructed in 1589–1599.
ABTS‐Multiwalled Carbon Nanotubes Nanocomposite/Bi Film Electrode for Sensitive Determination of Cd and Pb by Differential Pulse Stripping Voltammetry
Authors: Deng Wenfang , Tan Yueming , Fang Zhengfa , Xie Qingji , Li Yunyong , Liang Xiaoling , Yao Shouzhuo
Published: October 2009

A 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) diammonium salt (ABTS)‐multiwalled carbon nanotubes (MWCNTs) nanocomposite/Bi film modified glassy carbon (GC) electrode was constructed for the differential pulse stripping voltammetric determination of trace Pb2+ and Cd2+. This electrode was more sensitive than ABTS‐free Bi/GC and Bi/MWCNTs/GC electrodes. Linear responses were obtained in the range from 0.5 to 35 μg L−1 for Cd2+ and 0.2 to 50 μg L−1 Pb(II), with detection limits of 0.2 μg L−1 for Cd2+ and 0.1 μg L−1 for Pb2+, respectively. This sensor was applied to the simultaneous detection of Cd2+ and Pb2+ in water samples with satisfactory recovery.
Preparation of Polypyrrole/Nuclear Fast Red Films on Gold Electrode and Its Application on the Electrocatalytic Determination of Methyl‐dopa and Ascorbic Acid
Authors: Gholivand Mohammad Bagher , Amiri Masoud
Published: October 2009

A novel voltammetric method using the Ppyox/NFR/Au (poly pyrrole – nuclear fast red – gold) modified electrode was developed for simultaneous measurement of various combinations of ascorbic acid (AA) and methyldopa (MDA). Polypyrrole film was prepared by incorporation of nuclear fast red (NFR) as doping anion, during the electropolymerization of pyrrole onto a gold (Au) electrode in aqueous solution using cyclic voltammetric (CV) method, and then it was overoxidized at constant potential. Differential pulse voltammetry was utilized for the measurement of both analytes using modified electrode. Well‐separated voltammetric peaks were observed for ascorbic acid (AA) and methyldopa at the Ppyox/NFR/Au modified electrodes with peak separation of 0.210 V. It has been found that under optimum condition (pH 3.0), the oxidation of AA and MDA at the surface of the electrode occurs at a potential about 260 and 50 mV less positive than unmodified Au electrode respectively. The current catalytic oxidation peaks showed a linear dependent on the concentration of AA and MDA in the range of 9.0×10−6 to 1.0×10−3 and 1.0×10−7 to 2.0×10−5 mol L−1 respectively. The detection limit of 5.8×10−6 and 5.0×10−8 mol L−1 (S/N=3) were obtained for AA and MDA respectively. The modified electrode was used for determination of AA and MDA in some real samples such as human serum and tablet.
Protection of seismic structures using semi‐active friction TMD
Authors: Lin Chi‐Chang , Lin Ging‐Long , Wang Jer‐Fu
Published: October 2009

Although the design and applications of linear tuned mass damper (TMD) systems are well developed, nonlinear TMD systems are still in the developing stage. Energy dissipation via friction mechanisms is an effective means for mitigating the vibration of seismic structures. A friction‐type TMD, i.e. a nonlinear TMD, has the advantages of energy dissipation via a friction mechanism without requiring additional damping devices. However, a passive‐friction TMD (PF‐TMD) has such disadvantages as a fixed and pre‐determined slip load and may lose its tuning and energy dissipation abilities when it is in the stick state. A novel semi‐active‐friction TMD (SAF‐TMD) is used to overcome these disadvantages. The proposed SAF‐TMD has the following features. (1) The frictional force of the SAF‐TMD can be regulated in accordance with system responses. (2) The frictional force can be amplified via a braking mechanism. (3) A large TMD stroke can be utilized to enhance control performance. A non‐sticking friction control law, which can keep the SAF‐TMD activated throughout an earthquake with an arbitrary intensity, was applied. The performance of the PF‐TMD and SAF‐TMD systems in protecting seismic structures was investigated numerically. The results demonstrate that the SAF‐TMD performs better than the PF‐TMD and can prevent a residual stroke that may occur in a PF‐TMD system. Copyright © 2009 John Wiley & Sons, Ltd.
Fast performance uncertainty estimation via pushover and approximate IDA
Authors: Fragiadakis Michalis , Vamvatsikos Dimitrios
Published: October 2009

Approximate methods based on the static pushover are introduced to estimate the seismic performance uncertainty of structures having non‐deterministic modeling parameters. At their basis lies the use of static pushover analysis to approximate Incremental Dynamic Analysis (IDA) and estimate the demand and capacity epistemic uncertainty. As a testbed we use a nine‐storey steel frame having beam hinges with uncertain moment–rotation relationships. Their properties are fully described by six, randomly distributed, parameters. Using Monte Carlo simulation with Latin hypercube sampling, a characteristic ensemble of structures is created. The Static Pushover to IDA (SPO2IDA) software is used to approximate the IDA capacity curve from the appropriately post‐processed results of the static pushover. The approximate IDAs allow the evaluation of the seismic demand and capacity for the full range of limit‐states, even close to global dynamic instability. Moment‐estimating techniques such as Rosenblueth's point estimating method and the first‐order, second‐moment (FOSM) method are adopted as simple alternatives to obtain performance statistics with only a few simulations. The pushover is shown to be a tool that combined with SPO2IDA and moment‐estimating techniques can supply the uncertainty in the seismic performance of first‐mode‐dominated buildings for the full range of limit‐states, thus replacing semi‐empirical or code‐tabulated values (e.g. FEMA‐350), often adopted in performance‐based earthquake engineering. Copyright © 2009 John Wiley & Sons, Ltd.
How does overeaters anonymous help its members? A qualitative analysis
Authors: Russell‐Mayhew Shelly , von Ranson Kristin M. , Masson Philip C.
Published: October 2009

Overeaters Anonymous (OA) is a 12‐step, self‐help group for individuals who perceive themselves to have problems with compulsive overeating. Despite the popularity of OA and the frequent use of addictions‐based treatments for eating disorders, little is known about how OA is helpful. The purpose of this qualitative study was to explore members' experiences with and perceptions of OA. We conducted three focus groups with self‐selected members of OA (N = 20). We present three primary themes that emerged from the analysis of the focus groups' discussions, which emphasize why individuals entered OA, OA's ‘tools’, and how individuals perceived OA to ‘work’. Overall, although participants agreed OA was helpful to them, there was no consensus regarding how OA ‘works’. Copyright © 2009 John Wiley & Sons, Ltd and Eating Disorders Association.
STrengthening the REporting of Genetic Association Studies (STREGA)—an extension of the STROBE statement
Authors: Little Julian , Higgins Julian P. T. , Ioannidis John P. A. , Moher David , Gagnon France , von Elm Erik , Khoury Muin J. , Cohen Barbara , Davey‐Smith George , Grimshaw Jeremy , Scheet Paul , Gwinn Marta , Williamson Robin E. , Zou Guang Yong , Hutchings Kim , Johnson Candice Y. , Tait Valerie , Wiens Miriam , Golding Jean , van Duijn Cornelia , McLaughlin John , Paterson Andrew , Wells George , Fortier Isabel , Freedman Matthew , Zecevic Maja , King Richard , Infante‐Rivard Claire , Stewart, Alex , Birkett Nick
Published: October 2009

Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the STrengthening the Reporting of OBservational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy‐Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis. Genet. Epidemiol. 33:581–598, 2009. © 2009 Wiley‐Liss, Inc.
Specific somatotopic organization of functional connections of the primary motor network during resting state
Authors: van den Heuvel Martijn P. , Hulshoff Pol Hilleke E.
Published: October 2009

Regions of the primary motor network are known to show a high level of spontaneous functional connectivity during rest. Resting‐state functional magnetic resonance imaging (fMRI) studies have reported the left and right motor cortex to form a single resting‐state network, without examining the specific organization of the functional connections between subregions of the primary motor network. The primary motor cortex has a somatotopic organization, clearly separating regions that control our feet from regions that control our fingers and other body parts. In this study, 3 T resting‐state fMRI time‐series of 46 healthy subjects were acquired; and for all subregions along the precentral gyrus, the location of the maximum level of functional connectivity within the contralateral primary motor cortex was computed, together with whole brain functional connectivity maps, to examine a possible somatotopic organization of the functional connections of the motor network. Subregions of the primary motor cortex were found to be most strongly functionally linked to regions in the contralateral hemisphere with a similar spatial location along the contralateral primary motor cortex as the selected seed regions. On the basis of the knowledge of a somatopic organization of the primary motor network, these findings suggest that functional subregions of the motor network are one‐on‐one linked to their functional homolog in the contralateral hemisphere and organized in a somatotopic fashion. Examining the specific organization of the functional connections within the primary motor network could enhance our overall understanding of the organization of resting‐state functional communication within the brain. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Inhibition of invasion and migration of salivary gland adenocarcinoma cells by 5′‐nitro‐indirubinoxime (5′‐NIO)
Authors: Yoon Ji‐Hye , Kim Soo‐A , Kim Jae‐Il , Park Jong‐Hwan , Ahn Sang‐Gun , Yoon Jung‐Hoon
Published: October 2009

Background.

5′‐Nitro‐indirubinoxime (5′‐NIO) is a derivative of the bis‐indole indirubin that exhibits anticancer activities. The present study investigated the anti‐invasive action of 5′‐NIO in salivary gland ductal adenocarcinoma, SGT cells.

Methods.

The wound‐scratch, migration, and invasion assays were applied to determine the effect of 5′‐NIO on the migration capacity and invasiveness of SGT cells. Reverse‐transcriptase–polymerase chain reaction (RT‐PCR) and Western blot were performed to evaluate the impacts of 5′‐NIO on the expression of β1 integrin and matrix metalloproteinases MMP‐2 (gelatinase‐A) and MMP‐9 (gelatinase‐B).

Results.

The viability of SGT cells was decreased by 5′‐NIO in a dose‐dependent manner, but not significant at the concentrations of 0.5 and 1 μM. Under the concentrations showing little cytotoxic effect, 5′‐NIO exhibited a dose‐dependent inhibitory effect on the invasion and migration of SGT cells. Furthermore, 5′‐NIO suppressed the mRNA and protein expression of β1 integrin and MMP‐2 and MMP‐9.

Conclusion.

Taken together, these results suggest that 5′‐NIO, even at low concentrations, may effectively inhibit the invasion and migration of SGT cells by suppressing β1 integrin–mediated signaling. © 2009 Wiley Periodicals, Inc. Head Neck, 2010