bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractAttempts 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

AbstractBACKGROUND: 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

AbstractA 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

AbstractSynthetic 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

AbstractMany 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

AbstractThe 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

AbstractSomatostatin 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

AbstractThe 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

AbstractMembrane 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

AbstractIn 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

AbstractCognitive 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

AbstractThe 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

AbstractThe 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

AbstractPromoter 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

AbstractApplication 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