bluuebunny/crossref_metadata_2025 huggingface dataset:
Cigarette smoke extract regulates cytosolic phospholipase A2expression via NADPH oxidase/MAPKs/AP‐1 and p300 in human tracheal smooth muscle cells
Authors: Cheng Shin‐Ei , Lin Chih‐Chung , Lee I‐Ta , Hsu Chih‐Kai , Kou Yu Ru , Yang Chuen‐Mao
Published: November 2010

Up‐regulation of cytosolic phospholipase A2(cPLA2) by cigarette smoke extract (CSE) may play a critical role in airway inflammatory diseases. However, the mechanisms underlying CSE‐induced cPLA2expression in human tracheal smooth muscle cells (HTSMCs) were not completely understood. Here, we demonstrated that CSE‐induced cPLA2protein and mRNA expression was inhibited by pretreatment with the inhibitors of AP‐1 (tanshinone IIA) and p300 (garcinol) or transfection with siRNAs of c‐Jun, c‐Fos, and p300. Moreover, CSE also induced c‐Jun and c‐Fos expression, which were inhibited by pretreatment with the inhibitors of NADPH oxidase (diphenyleneiodonium chloride and apocynin) and the ROS scavenger (N‐acetyl‐L‐cysteine) or transfection with siRNAs of p47phoxand NADPH oxidase (NOX)2. CSE‐induced c‐Fos expression was inhibited by pretreatment with the inhibitors of MEK1 (U0126) and p38 MAPK (SB202190) or transfection with siRNAs of p42 and p38. CSE‐induced c‐Jun expression and phosphorylation were inhibited by pretreatment with the inhibitor of JNK1/2 (SP600125) or transfection with JNK2 siRNA. CSE‐stimulated p300 phosphorylation was inhibited by pretreatment with the inhibitors of NADPH oxidase and JNK1/2. Furthermore, CSE‐induced p300 and c‐Jun complex formation was inhibited by pretreatment with diphenyleneiodonium chloride, apocynin, N‐acetyl‐L‐cysteine or SP600125. These results demonstrated that CSE‐induced cPLA2expression was mediated through NOX2‐dependent p42/p44 MAPK and p38 MAPK/c‐Fos and JNK1/2/c‐Jun/p300 pathways in HTSMCs. J. Cell. Biochem. 112: 589–599, 2011. © 2010 Wiley‐Liss, Inc.
Rho GTPase‐mediated cytoskeletal organization in Schlemm's canal cells play a critical role in the regulation of aqueous humor outflow facility
Authors: Kumar Janardan , Epstein David L.
Published: November 2010

The increased intraocular pressure (IOP) has been considered to be an increased resistance of the aqueous humor outflow through the inner wall of Schlemm's canal (SC) and/or the juxtacanalicular tissue (JCT). The Rho GTPase‐regulated actomyosin organization appears to be an important mechanistic determinant of aqueous humor outflow facility. Therefore, in this study, we have evaluated the effects of modulating Rho GTPase activity on actomyosin cytoskeletal organization, monolayer permeability/barrier function of human SC cells, and aqueous humor outflow facility in enucleated porcine eyes ex vivo. Human SC cells, isolated from cadaver eyes, were treated with either Rho GTPase activators such as thrombin and lysophosphatidic acid (LPA), or a specific inhibitor (C3‐exoenzyme) of Rho GTPases. Treatment of SC cells with thrombin and LPA led to increased formation of stress fibers, focal adhesion, and increased myosin light chain phosphorylation, whereas treatment with C3‐exoenzyme showed the opposite effects like H‐7 and ECA, known for increasing the outflow facility in porcine eyes. The findings presented here suggest that LPA and thrombin, presumably through activation of Rho GTPase‐mediated actomyosin cytoskeletal reorganization in SC cells, cause a decrease in monolayer permeability of SC cells as well as a decrease in outflow facility of porcine eyes in ex vivo. Our results suggest that decrease in aqueous humor outflow may be correlated better with the changes in cytoskeletal organizations of SC, which could be the prime locus of the outflow resistance. J. Cell. Biochem. 112: 600–606, 2011. © 2010 Wiley‐Liss, Inc.
Changes in matrix protein gene expression associated with mineralization in the differentiating chick limb‐bud micromass culture system
Authors: Teixeira Cristina C. , Xiang Jenny , Roy Rani , Kudrashov Valery , Binderman Itzhak , Mayer‐Kuckuk Philipp , Boskey Adele L.
Published: November 2010

Chick limb‐bud mesenchymal stem cells plated in high density culture in the presence of 4 mM inorganic phosphate and vitamin C differentiate and form a mineralizable matrix, resembling that of the chick growth plate. To further elucidate the mechanism that allows these cultures to form physiologic hydroxyapatite deposits, and how the process can be manipulated to gain insight into mineralization mechanisms, we compared gene expression in mineralizing (with 4 mM inorganic phosphate) and non‐mineralizing cultures (containing only 1 mM inorganic phosphate) at the start of mineralization (day 11) and after mineralization reached a plateau (day 17) using a chick specific microarray. Based on replicate microarray experiments and K‐cluster analysis, several genes associated with the mineralization process were identified, and their expression patterns confirmed throughout the culture period by quantitative RT‐PCR. The functions of bone morphogenetic protein 1, BMP1, dentin matrix protein 1, DMP1, the sodium phosphate co‐transporter, NaPi IIb, matrix metalloprotease 13. MMP‐13, and alkaline phosphatase, along with matrix protein genes (type X collagen, bone sialoprotein, and osteopontin) usually associated with initiation of mineralization are discussed. J. Cell. Biochem. 112: 607–613, 2011. © 2010 Wiley‐Liss, Inc.
Stem cell property epithelial‐to‐mesenchymal transition is a core transcriptional network for predicting cetuximab (Erbitux™) efficacy in KRAS wild‐type tumor cells
Authors: Oliveras‐Ferraros Cristina , Vazquez‐Martin Alejandro , Cufí Sílvia , Queralt Bernardo , Báez Luciana , Guardeño Raquel , Hernández‐Yagüe Xavier , Martin‐Castillo Begoña , Brunet Joan , Menendez Javier A.
Published: November 2010

Beyond a well‐recognized effect of KRAS mutations in determining de novo inefficacy of cetuximab (CTX) in metastatic colorectal cancer, we urgently need a biomarker signature for predicting CTX efficacy in KRAS wild‐type (WT) tumors. CTX‐adapted EGFR gene‐amplified KRAS WT tumor cell populations were induced by stepwise‐chronic exposure of A431 epidermoid cancer cells to CTX. Genome‐wide analyses of 44K Agilent's whole human arrays were bioinformatically evaluated by Gene Set Enrichment Analysis (GSEA)‐based screening of the KEGG pathway database. Molecular functioning of CTX was found to depend on: (i) The occurrence of a positive feedback loop on Epidermal Growth Factor Receptor (EGFR) activation driven by genes coding for EGFR ligands (e.g., amphiregulin); (ii) the lack of a negative feedback on mitogen‐activated protein kinase (MAPK) activation regulated by dual‐specificity phosphatases (e.g., DUSP6) and; (iii) the transcriptional status of gene pathways controlling the epithelial‐to‐mesenchymal transition (EMT) and its reversal (MET) program (actin cytoskeleton and cell–cell communication—e.g., keratins—focal adhesion signaling—e.g., integrins—and EMT‐inducing cytokines – e.g., transforming growth factor‐β). Quantitative real‐time PCR, high‐content immunostaining, and flow‐cytometry analyses confirmed that CTX efficacy depends on its ability to promote: (i) Stronger cell–cell contacts by up‐regulating the expression of the epithelial markers E‐cadherin and occludin; (ii) down‐regulation of the epithelial transcriptional repressors Zeb, Snail, and Slug accompanied by restoration of cortical F‐actin; and (iii) complete prevention of the CD44pos/CD24neg/low mesenchymal immunophenotype. The impact of EGFR ligands/MAPK phosphatases gene transcripts in predicting CTX efficacy in KRAS WT tumors may be tightly linked with the ability of CTX to concurrently reverse the EMT status, a pivotal property of migrating cancer stem cells. J. Cell. Biochem. 112: 10–29, 2011. © 2010 Wiley‐Liss, Inc.
Role of endogenous TGF‐β family in myogenic differentiation of C2C12 cells
Authors: Furutani Yuuma , Umemoto Takenao , Murakami Masaru , Matsui Tohru , Funaba Masayuki
Published: November 2010

The present study evaluated endogenous activities and the role of BMP and transforming growth factor‐β (TGF‐β), representative members of the TGF‐β family, during myotube differentiation in C2C12 cells. Smad phosphorylation at the C‐terminal serines was monitored, since TGF‐β family members signal via the phosphorylation of Smads in a ligand‐dependent manner. Expression of phosphorylated Smad1/5/8, which is an indicator of BMP activity, was higher before differentiation, and rapidly decreased after differentiation stimulation. Differentiation‐related changes were consistent with those in the expression of Ids, well‐known BMP‐responsive genes. Treatment with inhibitors of BMP type I receptors or noggin in C2C12 myoblasts down‐regulated the expression of myogenic regulatory factors, such as Myf5 and MyoD, leading to impaired myotube formation. Addition of BMP‐2 during the myoblast phase also inhibited myotube differentiation through the down‐regulation of Myf5 and MyoD. In contrast to endogenous BMP activity, the phosphorylation of Smad2, a TGF‐β‐responsive Smad, was higher 8–16 days after differentiation stimulation. A‐83‐01, an inhibitor of TGF‐β type I receptor, increased the expression of Myf5 and MyoD, and enhanced myotube formation. The present results reveal that endogenous activities of the TGF‐β family are changed during myogenesis in a pathway‐specific manner, and that the activities are required for myogenesis. J. Cell. Biochem. 112: 614–624, 2011. © 2010 Wiley‐Liss, Inc.
Hypoxia‐mediated biological control
Authors: Cassavaugh Jessica , Lounsbury Karen M.
Published: November 2010

When oxygen demand is greater than oxygen supply, cells need to rapidly adjust their metabolism in order for the tissue to survive. Oxygen sensing by an organism influences a host of processes including growth, development, metabolism, pH homeostasis, and angiogenesis. Hypoxia also contributes to a wide number of human diseases including vascular disease, inflammatory conditions and cancer. Recently, major advances have been made in understanding the response of cells and tissues to hypoxia with the goal of providing mechanistic insight and novel therapeutic targets. In this article we review both the normal biological effects of hypoxia as well as the alterations that occur in specific disease conditions with an emphasis on the cell signaling and gene transcription mechanisms that underlie the changes associated with chronic hypoxia. Comparisons of studies in the fields of cardiac ischemia and tumor angiogenesis reveal the complexities within the microenvironment that control responses to hypoxia. It is clear that more interaction between researchers in these fields will improve the development of therapies that either promote or prevent hypoxic responses. J. Cell. Biochem. 112: 735–744, 2011. © 2010 Wiley‐Liss, Inc.
Per‐1 is a specific clock gene regulated by parathyroid hormone (PTH) signaling in osteoblasts and is functional for the transcriptional events induced by PTH
Authors: Hanyu Ryo , Hayata Tadayoshi , Nagao Masashi , Saita Yoshitomo , Hemmi Hiroaki , Notomi Takuya , Nakamoto Tetsuya , Schipani Ernestina , Knonenbery Henry , Kaneko Kazuo , Kurosawa Hisashi , Ezura Yoichi , Noda Masaki
Published: November 2010

Per‐1 is one of the clock genes and is known to regulate various biological events including bone mass determination. Parathyroid hormone is anabolic to bone while the mechanism of its action is not fully understood. Here, we examined the role of PTH on Per‐1 gene expression under osteoblast specific PTH signaling. Constitutively active PTH receptor (caPPR) expressed specifically in osteoblasts in transgenic mice activates Per‐1 gene expression in bone. This is specific as expression of other clock gene Bmal‐1 is not affected by caPPR over‐expression. Per‐1 is also expressed in osteoblastic cell line. Interestingly, Per‐1 expression is required for PTH signaling‐induced CRE dependent transcription. This is forming a positive feed back loop in the anabolic action of PTH signaling and Per‐1 in bone. These data indicate that PTH singling in osteoblasts activates Per‐1 gene expression in vivo in association with its anabolic action in bone at least in part through the regulation of transcriptional events. J. Cell. Biochem. 112: 433–438, 2011. © 2010 Wiley‐Liss, Inc.
Neuronal chromatin dynamics of imprinting in development and disease
Authors: Leung Karen N. , Chamberlain Stormy J. , Lalande Marc , LaSalle Janine M.
Published: November 2010

Epigenetic mechanisms play essential roles in mammalian neurodevelopment and genetic mutations or chromosomal deletions or duplications of epigenetically regulated loci or pathways result in several important human neurodevelopmental disorders. Postnatal mammalian neurons have among the most structured and dynamic nuclear organization of any cell type. Human chromosome 15q11‐13 is an imprinted locus required for normal neurodevelopment and is regulated by a plethora of epigenetic mechanisms in neurons, including multiple noncoding RNAs, parentally imprinted transcription and histone modifications, large‐scale chromatin decondensation, and homologous pairing in mature neurons of the mammalian brain. Here, we describe the multiple epigenetic layers regulating 15q11‐13 gene expression and chromatin dynamics in neurons and propose a model of how noncoding RNAs may influence the unusual neuronal chromatin structure and dynamics at this locus. We also discuss the need for improved neuronal cell culture systems that model human 15q11‐13 and other neurodevelopmental disorders with epigenetic bases in order to test the mechanisms of chromatin dynamics and nuclear organization in neurons. Induced pluripotent stem cells and other stem cell technologies hold promise for improved understanding of and therapeutic interventions for multiple human neurodevelopmental disorders. J. Cell. Biochem. 112: 365–373, 2011. © 2010 Wiley‐Liss, Inc.
The effects of estrogen receptors α‐ and β‐specific agonists and antagonists on cell proliferation and energy metabolism in human bone cell line
Authors: Somjen D. , Katzburg S. , Sharon O. , Grafi‐Cohen M. , Knoll E. , Stern N.
Published: November 2010

In cultured human osteoblasts estradiol‐17β (E2) modulated DNA synthesis, the specific activity of creatine kinase BB (CK), 12 and 15 lipoxygenase (LO) mRNA expression and formation of 12‐ and 15‐hydroxyeicosatetraenoic acid (HETE). We now investigate the response of human bone cell line (SaOS2) to phytoestrogens and estrogen receptors (ER)‐specific agonists and antagonists. Treatment of SaSO2 with E2, 2,3‐bis (4‐hydroxyphenyl)‐propionitrile (DPN; ERβ‐specific agonist), 4,4′,4″‐[4‐propyl‐(1H)‐pyrazol‐1,3,5‐triyl] tris‐phenol (PPT; ERα‐specific agonist), biochainin A (BA), daidzein (D), genistein (G) and raloxifene (Ral) showed increased DNA synthesis and CK. Ral inhibited completely all stimulations except DPN and to some extent D. The ERα‐specific antagonist methyl‐piperidino‐pyrazole (MPP) and the ERβ‐specific antagonist 4‐[2‐phenyl‐5,7‐bis (tri‐fluoro‐methyl) pyrazolo [1,5‐a]pyrimidin‐3‐yl] phenol (PTHPP) inhibited DNA synthesis, CK and reactive oxygen species (ROS) formation induced by estrogens according to their receptors affinity. The LO inhibitor baicaleine inhibited only E2, DPN and G's effects. E2 and Ral unlike all other compounds had no effect on ERα mRNA expression, while ERβ mRNA expression was stimulated by all compounds. All compounds modulated the expression of 12LO and 15LO mRNA, except E2, PPT and Ral for 12LO, and 12‐ and 15‐HETE productions and stimulated ROS formation which was inhibited by NADPH oxidase inhibitors diphenyleneiodonium chloride (DPI) and N‐acetyl cysteine and the estrogen inhibitor ICI. DPI did not affect hormonal‐induced DNA and CK. In conclusion, we provide evidence for the separation of mediation via ERα and ERβ pathways in the effects of estrogenic compounds on osteoblasts, but the role of LO/HETE/ROS is unclear. J. Cell. Biochem. 112: 625–632, 2011. © 2010 Wiley‐Liss, Inc.
Differential roles of hypoxia inducible factor subunits in multipotential stromal cells under hypoxic condition
Authors: Tamama Kenichi , Kawasaki Haruhisa , Kerpedjieva Svetoslava S. , Guan Jianjun , Ganju Ramesh K. , Sen Chandan K.
Published: November 2010

Cell therapy with bone marrow multipotential stromal cells (MSCs) represents a promising approach to promote wound healing and tissue regeneration. MSCs expanded in vitro lose early progenitors with differentiation and therapeutic potentials under normoxic condition, whereas hypoxic condition promotes MSC self‐renewal through preserving colony forming early progenitors and maintaining undifferentiated phenotypes. Hypoxia inducible factor (HIF) pathway is a crucial signaling pathway activated in hypoxic condition. We evaluated the roles of HIFs in MSC differentiation, colony formation, and paracrine activity under hypoxic condition. Hypoxic condition reversibly decreased osteogenic and adipogenic differentiation. Decrease of osteogenic differentiation depended on HIF pathway; whereas decrease of adipogenic differentiation depended on the activation of unfolded protein response (UPR), but not HIFs. Hypoxia‐mediated increase of MSC colony formation was not HIF‐dependent also. Hypoxic exposure increased secretion of VEGF, HGF, and basic FGF in a HIF‐dependent manner. These findings suggest that HIF has a limited, but pivotal role in enhancing MSC self‐renewal and growth factor secretions under hypoxic condition. J. Cell. Biochem. 112: 804–817, 2011. © 2010 Wiley‐Liss, Inc.
Combined activin A/LiCl/Noggin treatment improves production of mouse embryonic stem cell‐derived definitive endoderm cells
Authors: Li Fuming , He Zhiying , Li Yangfang , Liu Pingyu , Chen Fei , Wang Minjun , Zhu Haiying , Ding Xiaoyan , Wangensteen Kirk J. , Hu Yiping , Wang Xin
Published: November 2010

Induction of definitive endoderm (DE) cells is a prerequisite for the whole process of embryonic stem (ES) cells differentiating into hepatic or pancreatic progenitor cells. We have established an efficient method to induce mouse ES cell‐derived DE cells in suspension embryonic body (EB) culture. Similar to previous studies, mouse ES cell‐derived DE cells, which were defined as Cxcr4+c‐Kit+, Cxcr4+E‐cadherin+ cells or Cxcr4+PDGFRa− cells, could be induced in the serum‐free EBs at Day 4 of induction. The activations of Wnt, Nodal, and FGF signaling pathways in differentiating EBs promoted DE cell differentiation, while activation of BMP4 signaling inhibited the process. In the present study, we found that chemical activation of canonical Wnt signaling pathway by LiCl could synergize with Activin A‐mediated Nodal signaling pathway to promote induction of DE cells, and inhibition of Bmp4 signaling by Noggin along with Activin A/LiCl further improved the efficiency of DE cell differentiation. The derived DE cells were proved for their capacities to become hepatic progenitor cells or pancreatic progenitor cells. In conclusion, we significantly improved the efficiency of generating mouse ES cell‐derived DE cells by combined Activin A/LiCl/Noggin treatment. Our work will be greatly helpful to generate ES cell‐derived hepatic cells and ES cell‐derived pancreatic cells for future regenerative medicine. J. Cell. Biochem. 112: 1022–1034, 2011. © 2010 Wiley‐Liss, Inc.
Bayesian model selection for meta‐analysis of diagnostic test accuracy data: Application to Ddimer for deep vein thrombosis
Authors: Novielli Nicola , Cooper Nicola J. , Sutton Alexander J. , Abrams Keith R.
Published: November 2010

A number of statistical models have been developed for meta‐analysis (MA) of diagnostic test (DT) accuracy data. Here we consider these alternative MA models, explore the relationships between them, and consider the use of the deviance information criteria (DIC) to decide which is the most appropriate model for a given dataset. A Bayesian statistical approach is adopted throughout. The alternative MA models are applied to a dataset of 198 assays of Ddimer to diagnose deep vein thrombosis. In this example, based on the DIC, a bivariate random effects model for sensitivity and specificity fitted the data best. When considering the inclusion of study level covariates, allowing sensitivity to vary by study setting further improved the fit of the model. The model fitting approach is then repeated for a subset of the data, which highlights the less decisive results obtained when using the DIC with a more limited dataset. Formal approaches to model selection are often overlooked in an MA context; however, they offer sensible rationale to the analysis, particularly for complex models such as those proposed for DT accuracy. Specifically, the use of the DIC statistic appears to be well suited for deciding between potentially complex mixed‐effect MA models, possibly including covariates. Copyright © 2010 John Wiley & Sons, Ltd.
Family functioning and posttraumatic stress symptoms in youth and their parents after unintentional pediatric injury
Authors: Coakley Rachael M. , Forbes Peter W. , Kelley Susan Douglas , LeBovidge Jennifer , Beasley Pamela , DeMaso David R. , Waber Deborah P.
Published: November 2010

This study examined the association between family functioning and the development of posttraumatic stress symptoms (PTSS) in youth and parents following an unintentional traumatic injury of a child. Fifty‐one parent–child dyads completed questionnaires and a structured interview assessing PTSS and family functioning. Multiple regression analyses were applied to evaluate the contribution of family functioning to the development of PTSS after controlling for demographic characteristics and known predictors. Family functioning had both direct and moderating influences on the development of PTSS in parents. We were unable to demonstrate a systematic impact of family functioning on the development of PTSS in children from the same families.
The dynamics of relational and contractual governance mechanisms in knowledge sharing of collaborative R&D projects
Authors: Olander Heidi , Hurmelinna‐Laukkanen Pia , Blomqvist Kirsimarja , Ritala Paavo
Published: November 2010

The purpose of this paper is to explore the dynamics of relational and contractual governance mechanisms in vertical buyer–supplier R&D projects requiring both knowledge sharing and protection. Prior literature has recognised the mutual impact of relational and contractual governance on knowledge sharing, but treats the linkages in a rather static way. This research introduces a more explicit process perspective, and combines four concepts: trust, relational norms, contracts and intellectual property rights (IPRs). The paper concentrates on the roles and interplay of both types of mechanisms in the different project phases. We collected qualitative interview data from four buyer–supplier R&D collaboration projects, each pair serving as a unit of analysis. Our findings indicate that both contractual and relational governance mechanisms play a role in buyer–supplier R&D collaboration but their relative importance varies according to the collaboration phase. Whereas in the exploration phase trust may even substitute contractual governance, both mechanisms support each other in the development phase. Contractual mechanisms are emphasised in the finalisation phase, although relational mechanisms also play a role. The lesson for management understanding is that both types of mechanisms should be considered simultaneously throughout the collaboration process. Copyright © 2010 John Wiley & Sons, Ltd.
Glycopolymer‐Grafted Polystyrene Nanospheres
Authors: Pfaff André , Shinde Vaishali S. , Lu Yan , Wittemann Alexander , Ballauff Matthias , Müller Axel H. E.
Published: November 2010

The synthesis and characterization of spherical sugar‐containing polymer brushes consisting of PS cores onto which chains of sugar‐containing polymers have been grafted via two different techniques are described. Photopolymerization in aqueous dispersion using the functional monomer MAGlc and crosslinked or non‐crosslinked PS particles covered with a thin layer of photo‐initiator yielded homogeneous glycopolymer brushes attached to spherical PS cores. As an alternative, ATRP was used to graft poly‐(N‐acetylglucosamine) arms from crosslinked PS cores. Deprotection of the grafted brushes led to water‐soluble particles that act as carriers for catalytically active gold nanoparticles. These glycopolymer chains show a high affinity to adsorb WGA whereas no binding to BSA or PNA could be detected.

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Folate‐Decorated Succinylchitosan Nanoparticles Conjugated with Doxorubicin for Targeted Drug Delivery
Authors: Sahu Sumanta Kumar , Maiti Swatilekha , Maiti Tapas Kumar , Ghosh Sudip K. , Pramanik Panchanan
Published: November 2010

Amphiphilic biodegradable succinylchitosan nanoparticles modified with folic acid are described that act as an emulsifier to form nanoparticles. Their molecular structures and physicochemical as well as self‐assembly properties are characterized by means of FT‐IR,1H NMR, FESEM, DLS, and TEM. The nanoparticles are 60–80 nm in size and are not toxic in vitro. They are immobilized with the cytostatic drug doxorubicin. Specific transport of doxorubicin by the nanoparticles into the folate‐receptor‐overexpressing cancer cells and its biological activity as well as in vitro release are demonstrated. It is shown that under acidic condition more drug is released. The nanoparticles can thus not only specifically deliver doxorubicin to its target, but also release the drug depending on the pH.

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Poly(ester urethane) Guides for Peripheral Nerve Regeneration
Authors: Chiono Valeria , Sartori Susanna , Rechichi Alfonsina , Tonda‐Turo Chiara , Vozzi Giovanni , Vozzi Federico , D'Acunto Mario , Salvadori Claudia , Dini Francesca , Barsotti Giovanni , Carlucci Fabio , Burchielli Silvia , Nicolino Silvia , Audisio Chiara , Perroteau Isabelle , Giusti Paolo , Ciardelli Gianluca
Published: November 2010

A biocompatible and elastomeric PU was synthesized from low‐molecular‐weight PCL as macrodiol, CMD as chain extender and HDI as chain linker for applications in the field of peripheral nerve repair. PU cast films supported in vitro attachment and proliferation of NOBEC. The in vitro adhesion and proliferation of S5Y5 neuroblastoma cells on the inner surface of uncoated, gelatin‐ and PL‐coated PU guides were compared. Due to their superior in vitro performance, PL‐coated PU guides were tested in vivo for the repair of 1.8 cm‐long defects in rat sciatic nerves. The progressive regeneration was confirmed by EMG and histological analysis showing the presence of regenerating fibers in the distal stumps.

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1H,1H,2H,2H‐Perfluorodecyl‐Acrylate‐Containing Block Copolymers from ARGET ATRP
Authors: Schreiber Ulrike , Hosemann Benjamin , Beuermann Sabine
Published: November 2010

Block copolymers of 1H,1H,2H,2H‐perfluorodecyl acrylate (AC8) were obtained from ARGET ATRP. To obtain block copolymers of low dispersity the PAC8 block was synthesized in anisole with a CuBr2/PMDETA catalyst in the presence of tin(II) 2‐ethylhexanoate as a reducing agent. The PAC8 block was subsequently used as macroinitiator for copolymerization with butyl andtert‐butyl acrylate carried out in scCO2. To achieve catalyst solubility in CO2two fluorinated ligands were employed. The formation of block copolymers was confirmed by size exclusion chromatography and DSC.

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Preparation and Recycling of Plasticized PLA
Authors: Scaffaro Roberto , Morreale Marco , Mirabella Filippo , La Mantia Francesco Paolo
Published: November 2010

PLA is one of the most interesting new polymeric materials, mainly because of its favorable environmental features. On the other hand, one of its drawbacks is represented by its brittleness and low impact resistance. A possible solution may be the use of proper impact modifiers. Furthermore, limited knowledge exists on the behavior of PLA upon recycling. In this paper, a detailed investigation has been carried out on the behavior of PLA systems upon adding small amounts of commercial impact modifiers, and the effects of multiple recycling steps have been studied. The use of impact modifiers can effectively improve mechanical properties. Recycling led to a significant reduction in the impact strength; however a relatively high fraction of the other mechanical properties was still retained.

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Sharp Hydrophilicity Switching and Conformality on Nanostructured Surfaces Prepared via Initiated Chemical Vapor Deposition (iCVD) of a Novel Thermally Responsive Copolymer
Authors: Alf Mahriah E. , Godfrin Paul D. , Hatton T. Alan , Gleason Karen K.
Published: November 2010

A novel thermally responsive copolymer p(NIPAAm‐co‐DEGDVE) is synthesized using the substrate independent method of iCVD and exhibits a sharp lower critical solution temperature (LCST) transition centered at ≈28.5 ± 0.3 °C determined via quartz crystal microbalance measurements with dissipation monitoring (QCM‐D). Swelling with water below the LCST produces a reversible change of ≈3× in film thickness. The layer is conformal on nanostructured surfaces including MWCNT forests and electrospun nanofiber mats. Modified planar substrates exhibit ≈30°change in static contact angle over the LCST, while through conformal coating on nanostructured substrates changes in static contact angle up to 135° are achieved. Additionally, coated surfaces exhibit temperature sensitive BSA adsorption measured by QCM‐D and is reversible as shown through fluorescence imaging of a coated electrospun nanofiber mat.

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Synthesis and Function of Double‐Stranded Helical Polymers and Oligomers
Authors: Furusho Yoshio , Yashima Eiji
Published: November 2010

The design and synthesis of artificial helical polymers and oligomers has attracted much interest, in connection with fascinating biological helices and their sophisticated functions as well as possible applications in novel chiral materials. The last half‐century has seen a significant advancement in the synthesis of single‐stranded helical polymers and oligomers, since the discovery of the helical structure of isotactic polypropylene. In contrast, the chemistry of double‐stranded helical counterparts is still premature. This paper highlights our recent achievements in the synthesis, structures, and functions of double‐stranded helical polymers and oligomers, stressing an important role of supramolecular chemistry in the design and synthesis of double helices with a controlled helical sense.

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Supported Neodymium Catalysts for Isoprene and rac‐β‐Butyrolactone Polymerization: Modulation of Reactivity by Controlled Grafting
Authors: Terrier Michael , Brulé Emilie , Vitorino Marta J. , Ajellal Noureddine , Robert Carine , Gauvin Régis M. , Thomas Christophe M.
Published: November 2010

A series of hybrid materials, bearing neodymium silylamide initiating groups, have been shown to mediate isoprene polymerization when combined with alkyl aluminum activators [methylaluminoxane, AlEt2Cl, Al(iBu)3]. The surface species nature and relative distribution were correlated with isoprene polymerization activity and selectivity. This approach to stereocontrol modulation has been extended to racemic β‐butyrolactone isoselective ring opening polymerization.

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The use of mass spectrometry to study amyloid‐β peptides
Authors: Grasso Giuseppe
Published: November 2010

Amyloid‐β peptide (Aβ) varies in size from 39 to 43 amino acids and arises from sequential β‐ and γ‐secretase processing of the amyloid precursor protein. Whereas the non‐pathological role for Aβ is yet to be established, there is no disputing that Aβ is now widely regarded as central to the development of Alzheimer's disease (AD). The so named “amyloid cascade hypothesis” states that disease progression is the result of an increased Aβ burden in affected areas of the brain. To elucidate the Aβ role in AD, many analytical approaches have been proposed as suitable tools to investigate not only the total Aβ load but also many other issues that are considered crucial for AD, such as: (i) the aggregation state in which Aβ is present; (ii) its interaction with other species or metals; (iii) its ability to induce oxidative stress; and (iv) its degradative pathways. This review provides an insight into the use of mass spectrometry (MS) in the field of Aβ investigation aimed to assess its role in AD. In particular, the different MS‐based approaches appliedin vitroandin vivothat can provide detailed information on the above‐mentioned issues are reviewed. Moreover, the advantages offered by the MS methods over all the other techniques are highlighted, together with the recent developments and uses of combined analytical approaches to detect and characterize Aβ. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:347–365, 2011
Structure elucidation of native N‐ and O‐linked glycans by tandem mass spectrometry (tutorial)
Authors: An Hyun Joo , Lebrilla Carlito B.
Published: November 2010

Oligosaccharides play important roles in many biological processes. However, the structural elucidation of oligosaccharides remains a major challenge due to the complexities of their structures. Mass spectrometry provides a powerful method for determining oligosaccharide composition. Tandem mass spectrometry (MS) provides structural information with high sensitivity. Oligosaccharide structures differ from other polymers such as peptides because of the large number of linkage combinations and branching. This complexity makes the analysis of oligosaccharide unique from that of peptides. This tutorial addresses the issue of spectral interpretation of tandem MS under conditions of collision‐induced dissociation (CID) and infrared multiphoton dissociation (IRMPD). The proper interpretation of tandem MS data can provide important structural information on different types of oligosaccharides including O‐ and N‐linked. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:560–578, 2011
Sample preparation methods for MALDI‐MS profiling of bacteria
Authors: Šedo Ondrej , Sedláček Ivo , Zdráhal Zbyněk
Published: November 2010

Direct matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) bacterial cell or lysate analysis appears to meet all the criteria required for a rapid and reliable analytical microorganism identification and taxonomical classification tool. Few‐minute analytical procedure providing information extending up to sub‐species level underlines the potential of the MALDI‐MS profiling in comparison with other methods employed in the field. However, the quality of MALDI‐MS profiles and consequently the performance of the method are influenced by numerous factors, which involve particular steps of the sample preparation procedure. This review is aimed at advances in development and optimization of the MALDI‐MS profiling methodology. Approaches improving the quality of the MALDI‐MS profiles and universal feasibility of the method are discussed. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:417–434, 2011
AM‐PM Conversion in a W‐band frequency quadrupler
Authors: Campos‐Roca Y.
Published: November 2010

The noise conversion properties of a W‐band PHEMT‐based frequency quadrupler have been investigated. The study includes the experimental evaluation of the quadrupler amplitude‐modulated to phase‐modulated (AM‐PM) conversion coefficient and its implications in the phase noise degradation. The results show that this effect must be taken into account at offset frequencies where the input PM/AM noise ratio is poor. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:47–51, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25621
A thin multi‐slotted dual patch UHF‐band metal‐mountable RFID tag antenna
Authors: Koskinen Tomi V. , Rajagopalan Harish , Rahmat‐Samii Yahya
Published: November 2010

This article presents an RFID (Radio Frequency Identification) tag antenna, which works in the 902–928 MHz band. The multi‐slotted dual patch tag antenna is designed for a 1.6‐mm‐thick substrate, and it can be mounted on metal without degradation in performance. Due to a low‐profile and simple structure, this antenna has more potential for mass production compared to earlier antenna designs. It is shown by simulations how the bandwidth can be increased by incorporating multiple slots in the radiating patch elements of the antenna. Design curves showing the effect of different tuning parameters on the tag performance are presented. The performance of the tag is evaluated both in free‐space and on metal plate and the simulated input impedance, power reflection and radiation patterns are presented. A prototype of this multi‐slotted dual patch tag antenna has been constructed and impedance measurements are performed for the proposed tag in free‐space and on metal plate. Finally, maximum readable distances for the tag are calculated. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:40–47, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25622
Calculating the noise performance of a Ge‐on‐Si schottky photodetector
Authors: Dutta Himadri Sekhar , Das N. R.
Published: November 2010

We present here a study on the noise performance of a Ge‐on‐Si resonant‐cavity‐enhanced schottky photodetector (PD). The present model for noise includes the effect of confinement of carriers at the Si/Ge heterointerface. Noise equivalent bandwidth, dark current, and minimum detectable power are computed. The results show that suitable choice of device dimensions and bias can be used to improve the noise performance of the PD in presence of heterointerface confinement. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:5–10, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25623
The method of lines and cylindrical waveguides with constant arbitrary cross sections
Authors: Hooshyar M. A.
Published: November 2010

A modified method of lines is developed for propagation of TM waves in waveguides with constant arbitrary cross sections. The proposed method finds the eigenmodes and associated wave functions in a very practical manner. Numerical performance and accuracy of the proposed method are examined for waveguides with well known characteristics and are found to be very satisfactory. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1–5, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25624
Read range reduction in UHF RFID due to antenna detuning and gain penalty
Authors: Lorenzo J. , Girbau D. , Lázaro A. , Villarino R.
Published: November 2010

This article proposes an analytical study of the link budget in UHF RFID which takes into account the effects of materials where the tags are adhered, and which permits to analyze the impact of detuning and gain penalty on the read range. The analysis is performed for two typical tag antenna topologies: a dipole antenna and a slot antenna. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:144–148, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25625
Third‐order dual‐band filter with dual‐band admittance inverter
Authors: Liu Wei‐Ping , Tung Yu‐Wei
Published: November 2010

In this article, stepped impedance resonator with dual‐band admittance inverter is proposed to design the dual‐band microstrip filter to operate at (2.4, 5.2) GHz and at (0.9, 2.3) GHz, respectively. The proposed dual‐band microstrip filter consists of stepped‐impedance resonators (SIRs) in shunt cascaded by dual‐band inverter. The half‐wavelength SIR is constructed to simultaneously excite the dual resonances at those specified frequencies. The dual‐band admittance inverter used is composed of two open stubs and one transmission line to make the contribution of the performance of the J‐admittance. The transmission zeros of the admittance inverter can also enhance that of SIRs. The enhanced transmission zeros can be designed on the basis of the required J value and characteristic impedances of the inverter. The study has indicated that the proposed structure and method can achieve the design goals of dual‐band filter. Experimental filters are fabricated and measured to confirm the design. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:140–143, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25626
Compact dualband bandpass filter with two transmission zeros using dual‐mode microstrip resonator and tapped‐line geometry
Authors: Yun Tae‐Soon , Noh Sun‐Kuk , Kim Hyung‐Jong , Oh Euy‐Kyo , Son Hong‐Min , Lee Jong‐Chul
Published: November 2010

In this article, the dualband bandpass filters (BPFs) using dual‐mode resonator are designed and implemented. Also, the J‐inverter is investigated as function of the impedance and the electrical length of the open‐stub in the dual‐mode λg/2 microstrip resonator. Especially, the dualband BPFs using dual‐mode resonator are realized by the stepped impedance resonator (SIR) structure and have good out‐of‐band performance as the inverter is alternating by the coupling structure and tapped‐line geometry. The first transmission zero of the dualband BPFs is made by the dual‐mode resonator and the second transmission zero is defined by the open‐stub of the tapped‐line geometry as a function of J‐inverter. The dualband BPF using dual‐mode resonator with two transmission zeros shows the insertion losses of 1.92 and 1.71 dB at the center frequency of 2.42 and 5.65 GHz, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:108–111, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25627
A hybrid star‐ring‐bus architecture for WDM metropolitan‐regional access networks
Authors: Kuo Shu‐Tsung , Kao Ming‐Seng , Peng Peng‐Chun
Published: November 2010

This work proposes a highly reliable, hybrid star‐ring‐bus architecture (SRBA) for broadband wavelength‐division multiplexed (WDM) regional access networks.A delta‐star network on the top level acts as high‐capacity trunk infrastructure, whose weakness in reliability is overcome by the self‐healing function of the concatenated ring network on the lower level. The ring network is divided into several delta regions, where the traffic load inside each region is unified to minimize the backup resources required in the network. On the bottom level, considerable bus subnets are constructed to serve end users. The idea of λ‐bands is introduced to efficiently manage wavelength carriers used in the network. Moreover, by means of the automatic protection switching (APS) systems in all the optical network units (ONUs), a minimum‐hop rerouting protection scheme against fiber failure(s) is designed. Specifically, we carry out an experimental network to demonstrate the feasibility and survivability of the proposed architecture. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:102–108, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25628
Printed PIFA with a T‐shaped coupling feed for quad‐band thin‐profile mobile phone application
Authors: Xi Dan , Yin Yingzeng , Wang Yan , Wen Lehu , Mo Yuannan
Published: November 2010

A quad‐band printed planar inverted‐F antenna with two meander strips is proposed, designed, and tested. Its geometry is mainly comprised of an inverted meandered U‐shaped shorting strip and a tunable T‐shaped shorting strip for providing two operating bands at center frequency about 900 MHz and 1940 MHz to cover four bands: GSM, DCS, PCS, and UMTS with a small area of 15 × 33 mm2. The antenna can be easily fed by a 50‐Ω feed‐line without any external matching circuit or lumped circuit elements for size reduction or bandwidth enhancement. It is easy to fabricate at low cost and especially fit for thin‐profile mobile phone application. Good impedance and radiation performances are obtained. Details of the proposed antenna and the obtained results are also presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:68–72, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25629
Application of the cut‐off resonator for microwave monitoring of transformer oil
Authors: Kapilevich Boris , Lipsky Anatoly , Litvak Boris
Published: November 2010

This paper describes a cut‐off resonator designed for testing transformer oil is proposed.The two kinds of transformer oil have been compared—“fresh” (unused) and “old” (used) for a long period in real‐world conditions. The experimental setup has been designed and assembled on the basis of the cut‐off resonator with plastic tube containing the tested oil. There was observed the shift of resonance curves of the measured insertion losses between the “old” and the “fresh” samples. Also, the “old” oil has higher insertion loss that is caused by increasing its loss tangent compared with the “fresh” oil. These parameters can be used for estimating quality of the transformer oils. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:66–68, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25630
A wideband low‐profile monopolar patch antenna
Authors: Zheng Shu‐Feng , Yin Ying‐Zeng , Ren Xue‐Shi , Liu Zhen‐Yang , Kang Le
Published: November 2010

A wideband low‐profile monopolar patch antenna is presented in this article. The proposed antenna consists of a circular‐ring patch shorted to the ground plane by four shorting posts and a coupling patch connected with a feeding probe for bandwidth improvement. This designed antenna can provide a wide operating band (68.5% for VSWR < 2) while keeping a low profile (about 7% of the free‐space wavelength at the lowest operating frequency) and it also offers stable monopole‐like radiation patterns over the operating band. An antenna prototype is fabricated for testing, and the measured results agree well with the simulated ones. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:28–32, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25631
Wideband‐modified bow‐tie slot antenna with a U‐shaped tuning stub
Authors: Yoon JoongHan
Published: November 2010

In this article, a novel design for a modified bow‐tie slot antenna with a U‐shaped tuning stub for broadband applications is presented.The prototype consists of a modified bow‐tie slot and a U‐shaped tuning stub for feeding. The simulation results show that the impedance matching of the proposed modified bow‐tie slot antenna was greatly affected by the feed gap between the modified bow‐tie slot and the tuning stub and by the size of the U‐shaped tuning stub. The experiment results indicated that the impedance bandwidth (Return Loss −10 dB definition) of the proposed modified bow‐tie slot antenna was about 2.73 GHz. Also, the radiation patterns and gains in the experiment results are presented and discussed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:23–28, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25632
Robust optimization of microwave structures using cosimulation‐based surrogate models
Authors: Koziel Slawomir
Published: November 2010

A robust and computationally efficient technique for design optimization of microwave structures is proposed.We exploit cosimulation‐based surrogate models with the essential couplings evaluated using electromagnetic (EM) solver and most of the designable parameters modeled by distributed circuit elements with physical dimensions corresponding to those of the structure being optimized. Good prediction capability of the surrogate model is ensured by the space mapping‐based alignment process. It is demonstrated that the proposed methodology is able to yield a satisfactory design at the computational cost corresponding to two or three EM simulations of the optimized structure. The design of two microstrip filters is presented for the sake of illustration. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:130–135, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25637