bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of an LED backlight thermal module
Authors: Su Ay , Chen S.Y. , Lin Y.C.
Published: September 2010

The present study uses a heat sink plate to conduct natural convection in order to examine different areas of the heat sink and the effects of mounting different quantities of LEDs on the same surface on the thermal mechanism performance. Based on the experimental results, when a heat sink plate is arranged vertically, the channel flow between the fins is parallel to gravity. The LED substrate plate temperature is different from that at the end of the fin, and rises with the increase of total power. The thermal resistance rises slowly and then declines with the increase of LED electric power. As for temperature change of the LED substrate and at the end of the fin, when the temperature difference is increased, it also increases the natural convection thrust. For thermal resistance, the environmental thermal resistance at the bottom of the heat sink plate is lower than at the middle and top sections. These LED power emissions will be changed synchronously.

Regarding the LED quantity control, the rate of increase is the highest for the heat sink plate with 30 pcs LED, and the temperature is very high for the heat sink plate with 45 and 60 pcs LEDs when the power approaches 1 W. Moreover, the rising rate is the lowest for the heat sink plate with 60 pcs LEDs. Depending on the brightness requirement, the illuminant is provided by 60 pcs LEDs to obtain a lower temperature so that the system can reduce the thermal protective design. Evidence shows that a high conductivity heat pipe embedded in the channel can provide a more uniform temperature distribution. The present study provides a further understanding on the influence of different illuminant densities on the heat sink structure and the temperature difference in an LED heat transfer device, in order to provide a reference for heat sink design of a backlight module and LED illuminant module evaluation. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/htj.20321
A study on the integration of micro‐reformer and high‐ temperature PEM fuel cell
Authors: Su Ay , Liu Ying‐Chieh , Lin Wei‐Chieh , Cheng Chih‐Kai , Hsieh Chung‐You
Published: September 2010

This study presented an integration platform for a methanol reformer and high‐temperature proton exchange membrane fuel cell (PEMFC). The methanol micro‐reformer was combined with the catalytic reaction section and reforming section, whereas the catalytic reaction section with Pt catalysis maintained the constant temperature environment for a reforming process. SRM reforming results showed that 74 to 74.9% hydrogen and 23.5 to 25.7% of carbon dioxide in the mixture product, and less than 2% of carbon monoxide, was produced. Using the reforming product of low carbon monoxide concentration and the highest methanol conversion rate, a micro reformer link with a fuel cell integration experiment was performed. Results showed a high temperature PEMFC with 3 to 4 W power output under methanol flow rates of 15 ml/hr. Due to the lower hydrogen pressure supplied from the micro reformer, the fuel cell power output may become unstable. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/htj.20322
Biologic markers of sun exposure and melanoma risk in women: Pooled case–control analysis
Authors: Olsen Catherine M. , Zens Michael S. , Green Adele C. , Stukel Therese A. , Holman C. D'Arcy J. , Mack Thomas , Elwood J. Mark , Holly Elizabeth A. , Sacerdote Carlotta , Gallagher Richard , Swerdlow Anthony J. , Armstrong Bruce K. , Rosso Stefano , Kirkpatrick Connie , Zanetti Roberto , Bishop Julia Newton , Bataille Veronique , Chang Yu‐Mei , Mackie Rona , Østerlind Anne , Berwick Marianne , Karagas Margaret R. , Whiteman David C.
Published: September 2010

A model has been proposed whereby melanomas arise through two distinct pathways dependent on the relative influence of host susceptibility and sun exposure. Such pathways may explain site‐specific patterns of melanoma occurrence. To explore this model, we investigated the relationship between melanoma risk and general markers of acute (recalled sunburns) and chronic (prevalent solar keratoses) sun exposure, stratified by anatomic site and host phenotype. Our working hypothesis was that head and neck melanomas have stronger associations with solar keratoses and weaker associations with sunburn than trunk melanomas. We conducted a collaborative analysis using original data from women subjects of 11 case–control studies of melanoma (2,575 cases, 3,241 controls). We adjusted for potential confounding effects of sunlamp use and sunbathing. The magnitude of sunburn associations did not differ significantly by melanoma site, nevus count or histologic subtype of melanoma. Across all sites, relative risk of melanoma increased with an increasing number of reported lifetime “painful” sunburns, lifetime “severe” sunburns and “severe” sunburns in youth (ptrend < 0.001), with pooled odds ratios (pORs) for the highest category of sunburns versus no sunburns of 3.22 [95% confidence interval (CI) 2.04–5.09] for lifetime “painful” sunburns, 2.10 (95%CI 1.30–3.38) for lifetime “severe” sunburns and 2.43 (95%CI 1.61–3.65) for “severe” sunburns in youth. Solar keratoses strongly increased the risk of head and neck melanoma (pOR 4.91, 95%CI 2.10–11.46), but data were insufficient to assess risk for other sites. Reported sunburn is strongly associated with melanoma on all major body sites.
Decomposing complete equipartite graphs into odd square‐length cycles: number of parts odd
Authors: Smith Benjamin R.
Published: September 2010

In this article, we introduce a new technique for obtaining cycle
decompositions of complete equipartite graphs from cycle decompositions of related multigraphs. We use this technique to prove that if n, m and λ are positive integers with n ≥ 3, λ≥ 3 and n and λ both odd, then the complete equipartite graph having n parts of size m admits a
decomposition into cycles of length λ2 whenever nm ≥ λ2 and λ divides m. As a corollary, we obtain necessary and sufficient conditions for the decomposition of any complete equipartite graph into cycles of length p2, where p is prime. © 2010 Wiley Periodicals, Inc. J Combin Designs 18:401‐414, 2010
pH control mechanisms of tumor survival and growth
Authors: Parks Scott K. , Chiche Johanna , Pouyssegur Jacques
Published: September 2010

A distinguishing phenotype of solid tumors is the presence of an alkaline cellular feature despite the surrounding acidic microenvironment. This phenotypic characteristic of tumors, originally described by Otto Warburg, arises due to alterations in metabolism of solid tumors. Hypoxic regions of solid tumors develop due to poor vascularization and in turn regulate the expression of numerous genes via the transcription factor HIF‐1. Ultimately, the tumor microenvironment directs the development of tumor cells adapted to survive in an acidic surrounding where normal cells perish. The provision of unique pH characteristics in tumor cells provides a defining trait that has led to the pursuit of treatments that target metabolism, hypoxia, and pH‐related mechanisms to selectively kill cancer cells. Numerous studies over the past decade involving the cancer‐specific carbonic anhydrase IX have re‐kindled an interest in pH disruption‐based therapies. Although an acidification of the intracellular compartment is established as a means to induce normal cell death, the defining role of acid–base disturbances in tumor physiology and survival remains unclear. The aim of this review is to summarize recent data relating to the specific role of pH regulation in tumor cell survival. We focus on membrane transport and enzyme studies in an attempt to elucidate their respective functions regarding tumor cell pH regulation. These data are discussed in the context of future directions for the field of tumor cell acid–base‐related research. J. Cell. Physiol. 226: 299–308, 2011. © 2010 Wiley‐Liss, Inc.
Characterization of mesenchymal stem cells from human normal and hyperplastic gingiva
Authors: Tang Liang , Li Nan , Xie Han , Jin Yan
Published: September 2010

Human gingiva plays an important role in the maintenance of oral health and shows unique fetal‐like scarless healing process after wounding. Here we isolate and characterize mesenchymal stem cells from human normal and hyperplastic gingival tissues (N‐GMSC and H‐GMSC, respectively). Immunocytochemical staining indicated that gingival lamina propria contained Stro‐1 and SSEA‐4 positive cells, implying existence of putative gingival MSC. Under attachment‐based isolating and culturing condition, gingival MSC displayed highly clonogenic and long‐term proliferative capability. By using single colony isolation and expansion approaches, we found both N‐GMSC and H‐GMSC possessed self‐renewal and multipotent differentiation properties. N‐GMSC and H‐GMSC showed distinct immunoregulatory functions in a murine skin allograft setting via up‐regulation of putative systemic regulatory T cells (Tregs). N‐GMSC and H‐GMSC were capable of regenerating collagenous tissue following in vivo transplantation, in which H‐GMSC exhibited more robust regenerative capability. These findings suggest that gingival tissue contains tissue‐specific mesenchymal stem cell population and is an ideal resource for immunoregulatory therapy due to its substantial availability and accessibility. In addition, gingival MSC over‐activation may contribute to gingival hyperplastic phenotype. J. Cell. Physiol. 226: 832–842, 2011. © 2010 Wiley‐Liss, Inc.
Dual regulation of hepatocyte apoptosis by reactive oxygen species: Increases in transcriptional expression and decreases in proteasomal degradation of BimEL
Authors: Ishihara Yasuhiro , Takeuchi Kenji , Ito Fumiaki , Shimamoto Norio
Published: September 2010

Reactive oxygen species (ROS) have a fundamental role in intracellular signaling transduction. We show here that time‐dependent extracellular signal‐regulated kinase (ERK) activation due to inactivation of protein tyrosine phosphatases was closely linked to hepatocyte apoptosis under sustained exposure to ROS, which is produced through inhibition of ROS‐scavenging enzymes. We found, for the first time, that active ERK transcriptionally increased BimEL expression among seven proteins of the Bcl‐2 family. Transfection of Bim siRNA inhibited BimEL expression and hepatocyte apoptosis. Although ERK activation also elicited BimEL phosphorylation and subsequent ubiquitination, exposure to ROS for 9 h decreased proteasome activity. Collectively, the amount of BimEL was elevated by its increased expression and decreased degradation, leading to apoptosis. Exposure to ROS for 6 h caused neither reduction of proteasome activity nor hepatocyte apoptosis. These results indicate that the duration of exposure to ROS determines the fate of cells, that is, survival or death, in addition to the species, amounts, and generation sites of ROS. J. Cell. Physiol. 226: 1007–1016, 2011. © 2010 Wiley‐Liss, Inc.
RARγ is required for correct deposition and removal of Suz12 and H2A.Z in embryonic stem cells
Authors: Amat Ramon , Gudas Lorraine J.
Published: September 2010

Retinoic acid (RA) induces embryonic stem cell differentiation. The effects of RA are mediated by retinoic acid receptors (RARs) that promote epigenetic changes controlling gene transcription. We show here that RARγ, in the absence of the ligand RA, is required for deposition of the histone variant H2A.Z and the polycomb group protein Suz12 at RA target genes, and that in embryonic stem cells both RARγ and Suz12 exist in a multi‐protein complex in the absence of ligand. Addition of RA causes removal of H2A.Z and Suz12 from RARγ target genes when the genes are transcriptionally activated. J. Cell. Physiol. 226: 293–298, 2011. © 2010 Wiley‐Liss, Inc.
Protein kinase D1 promotes anchorage‐independent growth, invasion, and angiogenesis by human pancreatic cancer cells
Authors: Ochi Nobuo , Tanasanvimon Suebpong , Matsuo Yoichi , Tong Zhimin , Sung Bokyung , Aggarwal Bharat B. , Sinnett‐Smith James , Rozengurt Enrique , Guha Sushovan
Published: September 2010

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal diseases. Novel molecularly targeted therapies are urgently needed. Here, we extended our studies on the role of protein kinase D1 (PKD1) in PDAC cell lines. Given that Panc‐1 express moderate levels of PKD1, we used retroviral‐mediated gene transfer to create a Panc‐1 derivative that stably over‐expresses PKD1 (Panc‐1‐PKD1). Reciprocally, we used shRNA targeting PKD1 in Panc‐28 to produce a PKD1 under‐expressing Panc‐28 derivative (Panc‐28‐shPKD1). Our results demonstrate that Panc‐1‐PKD1 cells exhibit significantly increased anchorage‐independent growth in soft agar and increased in vitro invasion compared with Panc‐1‐mock. Reciprocally, Panc‐28‐shPKD1 cells show a significant decrease in anchorage‐independent growth and invasiveness, as compared with Panc‐28‐mock cells. The selective PKD family inhibitor CRT0066101 markedly decreased colony‐forming ability and invasiveness by either Panc‐1‐PKD1 or Panc‐28‐mock cells. Secretion of the pro‐angiogenic factors vascular endothelial growth factor (VEGF) and CXC chemokines (CXCL8) was significantly elevated by PKD1 over‐expression in Panc‐1 cells and reduced either by depletion of PKD1 via shRNA in Panc‐28 cells or by addition of CRT0066101 to either Panc‐1‐PKD1 or Panc‐28‐mock cells. Furthermore, human umbilical vein endothelial cell (HUVEC) tube formation was significantly enhanced by co‐culture with Panc‐1‐PKD1 compared with Panc‐1‐mock in an angiogenesis assay in vitro. Conversely, PKD1 depletion in Panc‐28 cells decreased their ability to induce endotube formation by HUVECs. PDAC‐induced angiogenesis in vitro and in vivo was markedly inhibited by CRT0066101. Our results lend further support to the hypothesis that PKD family members provide a novel target for PDAC therapy. J. Cell. Physiol. 226: 1074–1085, 2011. © 2010 Wiley‐Liss, Inc.
3D imaging of telomeres and nuclear architecture: An emerging tool of 3D nano‐morphology‐based diagnosis
Authors: Knecht Hans , Mai Sabine
Published: September 2010

Patient samples are evaluated by experienced pathologists whose diagnosis guides treating physicians. Pathological diagnoses are complex and often assisted by the application of specific tissue markers. However, cases still exist where pathologists cannot distinguish between closely related entities or determine the aggressiveness of the disease they identify under the microscope. This is due to the absence of reliable markers that define diagnostic subgroups in several cancers. Three‐dimensional (3D) imaging of nuclear telomere signatures is emerging as a new tool that may change this situation offering new opportunities to the patients. This article will review current and future avenues in the assessment of diagnostic patient samples. J. Cell. Physiol. 226: 859–867, 2011. © 2010 Wiley‐Liss, Inc.
Blockade of TNFR1 signaling: A role of oscillatory fluid shear stress in osteoblasts
Authors: Wang Haifang , Young Suzanne R. , Gerard‐O'Riley Rita , Hum Julia M. , Yang Zhouqi , Bidwell Joseph P. , Pavalko Fredrick M.
Published: September 2010

Fluid shear stress protects cells from TNF‐α‐induced apoptosis. Oscillatory fluid shear stress (OFSS) is generally perceived as physiologically relevant biophysical signal for bone cells. Here we identify several cellular mechanisms responsible for mediating the protective effects of OFSS against TNF‐α‐induced apoptosis in vitro. We found that exposure of MC3T3‐E1 osteoblast‐like cells to as little as 5 min of OFSS suppressed TNF‐α‐induced activation of caspase‐3, cleavage of PARP and phosphorylation of histone. In contrast, H2O2‐induced apoptosis was not inhibited by OFSS suggesting that OFSS might not be protecting cells from TNF‐α‐induced apoptosis via stimulation of global pro‐survival signaling pathways. In support of this speculation, OFSS inhibition of TNF‐α‐induced apoptosis was unaffected by inhibitors of several pro‐survival signaling pathways including pI3‐kinase (LY294002), MAPK/ERK kinase (PD98059 or U0126), intracellular Ca2+ release (U73122), NO production (L‐NAME), or protein synthesis (cycloheximide) that were applied to cells during exposure to OFSS and during TNF‐α treatment. However, TNF‐α‐induced phosphorylation and degradation of IκBα was blocked by pre‐exposure of cells to OFSS suggesting a more specific effect of OFSS on TNF‐α signaling. We therefore focused on the mechanism of OFSS regulation of TNF‐receptor 1 (TNFR1) signaling and found that OFSS (1) reduced the amount of receptor on the cell surface, (2) prevented the association of ubiquitinated RIP in TNFR1 complexes with TRADD and TRAF2, and (3) reduced TNF‐α‐induced IL‐8 promoter activity in the nucleus. We conclude that the anti‐apoptotic effect of OFSS is not mediated by activation of universal pro‐survival signaling pathways. Rather, OFSS inhibits TNF‐α‐induced pro‐apoptotic signaling which can be explained by the down‐regulation of TNFR1 on the cell surface and blockade of TNFR1 downstream signaling by OFSS. J. Cell. Physiol. 226: 1044–1051, 2011. © 2010 Wiley‐Liss, Inc.
KIT receptor activation by autocrine and paracrine stem cell factor stimulates growth of merkel cell carcinoma in vitro
Authors: Krasagakis Konstantin , Fragiadaki Irene , Metaxari Maria , Krüger‐Krasagakis Sabine , Tzanakakis George N. , Stathopoulos Efstathios N. , Eberle Jürgen , Tavernarakis Nektarios , Tosca Androniki D.
Published: September 2010

The co‐expression of KIT receptor and its ligand stem cell factor (SCF) has been reported in biopsy specimens of Merkel cell carcinoma (MCC). However, the functional role of SCF/KIT in the pathogenesis of this aggressive tumor has not been elucidated. The present study reports expression and effects of SCF and KIT in the Merkel cell carcinoma cell line MCC‐1 in vitro. SCF and KIT were endogenously co‐expressed in MCC‐1 cells. Exogenous soluble SCF modulated KIT receptor mRNA and protein expression, stimulated growth of MCC‐1 cells, upregulated endogenous activation of KIT, AKT, and of extracellular signal‐regulated kinase (ERK) 1/2 signaling pathway. On the contrary, an inhibitory antibody that neutralized the KIT ligand binding site, reduced growth of MCC‐1 cells, as did high doses of the KIT kinase inhibitors imatinib and nilotinib. Also, inhibitors of KIT downstream effectors, U0126 that blocks MEK1/2 as well as wortmannin and LY294002 that inhibit phosphatidylinositol 3‐kinase‐dependent AKT phosphorylation, inhibited the proliferation of MCC‐1 cells. These data support the hypothesis that KIT is activatable by paracrine or autocrine tumor cell‐derived SCF and stimulates growth of Merkel cell carcinoma in vitro. Blockade of KIT and the downstream signaling cascade at various levels results in inhibition of Merkel cell carcinoma growth in vitro, suggesting targets for therapy of this cancer. J. Cell. Physiol. 226: 1099–1109, 2011. © 2010 Wiley‐Liss, Inc.
NAD(P)H oxidase participates in the palmitate‐induced superoxide production and insulin secretion by rat pancreatic islets
Authors: Graciano Maria Fernanda R. , Santos Laila R.B. , Curi Rui , Carpinelli Angelo R.
Published: September 2010

Nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase complex has been shown to be involved in the process of glucose‐stimulated insulin secretion (GSIS). In this study, we examined the effect of palmitic acid on superoxide production and insulin secretion by rat pancreatic islets and the mechanism involved. Rat pancreatic islets were incubated during 1 h with 1 mM palmitate, 1% fatty acid free‐albumin, 5.6 or 10 mM glucose and in the presence of inhibitors of NAD(P)H oxidase (DPI—diphenyleneiodonium), PKC (calphostin C) and carnitine palmitoyl transferase‐I (CPT‐I) (etomoxir). Superoxide content was determined by hydroethidine assays. Palmitate increased superoxide production in the presence of 5.6 and 10 mM glucose. This effect was dependent on activation of PKC and NAD(P)H oxidase. Palmitic acid oxidation was demonstrated to contribute for the fatty acid induction of superoxide production in the presence of 5.6 mM glucose. In fact, palmitate caused p47PHOXtranslocation to plasma membrane, as shown by immunohistochemistry. Exposure to palmitate for 1 h up‐regulated the protein content of p47PHOXand the mRNA levels of p22PHOX, gp91PHOX, p47PHOX, proinsulin and the G protein‐coupled receptor 40 (GPR40). Fatty acid stimulation of insulin secretion in the presence of high glucose concentration was reduced by inhibition of NAD(P)H oxidase activity. In conclusion, NAD(P)H oxidase is an important source of superoxide in pancreatic islets and the activity of NAD(P)H oxidase is involved in the control of insulin secretion by palmitate. J. Cell. Physiol. 226: 1110–1117, 2011. © 2010 Wiley‐Liss, Inc.
Monitoring of herbal mixtures potentially containing synthetic cannabinoids as psychoactive compounds
Authors: Dresen Sebastian , Ferreirós Nerea , Pütz Michael , Westphal Folker , Zimmermann Ralf , Auwärter Volker
Published: September 2010

Herbal mixtures like ‘Spice’ with potentially bioactive ingredients were available in many European countries since 2004 and are still widely used as a substitute for cannabis, although merchandized as ‘herbal incense’. After gaining a high degree of popularity in 2008, big quantities of these drugs were sold. In December 2008, synthetic cannabinoids were identified in the mixtures which were not declared as ingredients: the C8homolog of the non‐classical cannabinoid CP‐47,497 (CP‐47,497‐C8) and a cannabimimetic aminoalkylindole called JWH‐018. In February 2009, a few weeks after the German legislation put these compounds and further pharmacologically active homologs of CP‐47,497 under control, another cannabinoid appeared in ‘incense’ products: the aminoalkylindole JWH‐073.

In this paper, the results of monitoring of commercially available ‘incense’ products from June 2008 to September 2009 are presented. In this period of time, more than 140 samples of herbal mixtures were analyzed for bioactive ingredients and synthetic cannabimimetic substances in particular. The results show that the composition of many products changed repeatedly over time as a reaction to prohibition and prosecution of resellers. Therefore neither the reseller nor the consumer of these mixtures can predict the actual content of the ‘incense’ products. As long as there is no possibility of generic definitions in the controlled substances legislation, further designer cannabinoids will appear on the market as soon as the next legal step has been taken. This is affirmed by the recent identification of the aminoalkylindoles JWH‐250 and JWH‐398. As further cannabinoids can be expected to occur in the near future, a continuous monitoring of these herbal mixtures is required.

The identification of the synthetic opioidO‐desmethyltramadol in a herbal mixture declared to contain ‘kratom’ proves that the concept of selling apparently natural products spiked with potentially dangerous synthetic chemicals/pharmaceuticals is a continuing trend on the market of ‘legal highs’. Copyright © 2010 John Wiley & Sons, Ltd.
A pitfall of using 2‐[(2E)‐3‐(4‐tert‐butylphenyl)‐2‐methylprop‐2‐enylidene]malononitrile as a matrix in MALDI TOF MS: chemical adduction of matrix to analyte amino groups
Authors: Lou Xianwen , de Waal Bas F. M. , van Dongen Joost L. J. , Vekemans Jef A. J. M. , Meijer E. W.
Published: September 2010

2‐[(2E)‐3‐(4‐tert‐Butylphenyl)‐2‐methylprop‐2‐enylidene]malononitrile (DCTB) has been considered as an excellent matrix for matrix‐assisted laser desorption/ionization (MALDI) of many types of synthetic compounds. However, it might provide troublesome results for compounds containing aliphatic primary or secondary amino groups. For these compounds, strong extra ion peaks with a mass difference of 184.1 Da were usually observed, which might falsely indicate the presence of some unknown impurities that were not detected by other matrices. On the basis of the possible mechanisms proposed, these extra ions are the products of nucleophilic reactions between analyte amino groups and DCTB molecules or radical cations. In these reactions, an amino group replaces the dicyanomethylene group of DCTB forming a matrix adduct via a CN‐bond. An aliphatic primary amine could react easily with DCTB and the reaction could start once they are mixed in a MALDI solution. For an aliphatic secondary amine, on the other hand, the reaction most likely occurs in the gas phase. Protonation of amino groups by adding acid seems to be a useful way to stop DCTB adduction for compounds with one single amino group, but not for compounds with multiple amino groups. Unlike aliphatic primary or secondary amines, aliphatic tertiary amines and aromatic amines do not yield DCTB adducts. This is because tertiary amines do not have the required transferrable H‐(N) atom to form an extra CN‐bond, while aromatic amines are not sufficiently nucleophilic to attack DCTB. In view of the possible matrix adduction, care should be taken in MALDI time‐of‐flight mass spectrometry (TOF MS) when DCTB is used as the matrix for compounds containing amino group(s). Copyright © 2010 John Wiley & Sons, Ltd.
How factors secreted from astrocytes impact myelin repair
Authors: Moore Craig S. , Abdullah Shahana L. , Brown Andrew , Arulpragasam Amanda , Crocker Stephen J.
Published: September 2010

Over a century ago, hypertrophy of astrocytes was noted as a pathology of multiple sclerosis (MS) and was hypothesized to play an important role in this disease, yet the contribution of astrocytes has been largely underemphasized in the pathophysiology of CNS demyelination. Astrocytes perform many homeostatic functions within the developing and adult CNS, including enhancing formation and maintenance of the blood–brain barrier, moderating neuronal connections through the tripartite synapse, and perhaps evenoffering intercellular communication independently of neurons. Although there is a significant body of literature characterizing different types of MS lesions, the inflammatory demyelination in an active MS lesion is accompanied by the presence of macrophages, lymphocytes, and large reactive astrocytes. The astrocyte has long been viewed as a cell that promotes inflammation and demyelination, while also forming the glial scar, thus hindering remyelination and axon growth. Renewed interest in the astrocyte has been brought about by recent studies demonstrating that astrocytes can also function as cellular mediators of CNS myelination by promoting oligodendrocyte progenitor migration, proliferation, and differentiation. Thus, refining our knowledge of astrocytic functions in the regulation of CNS myelination may help us to better understand why remyelination fails in MS. © 2010 Wiley‐Liss, Inc.
Reduced expression and activation of voltage‐gated sodium channels contributes to blunted baroreflex sensitivity in heart failure rats
Authors: Tu Huiyin , Zhang Libin , Tran Thai P. , Muelleman Robert L. , Li Yu‐Long
Published: September 2010

Voltage‐gated sodium (Nav) channels are responsible for initiation and propagation of action potential in the neurons. To explore the mechanisms of chronic heart failure (CHF)‐induced baroreflex dysfunction, we measured the expression and current density of Nav channel subunits (Nav1.7, Nav1.8, and Nav1.9) in the aortic baroreceptor neurons and investigated the role of Nav channels in aortic baroreceptor neuron excitability and baroreflex sensitivity in sham and CHF rats. CHF was induced by left coronary artery ligation. The development of CHF (6–8 weeks after the coronary ligation) was confirmed by hemodynamic and morphological characteristics. Immunofluorescent data indicated that Nav1.7 was expressed in A‐type (myelinated) and C‐type (unmyelinated) nodose neurons, but Nav1.8 and Nav1.9 were expressed only in C‐type nodose neurons. Real‐time RT‐PCR and Western blot data showed that CHF reduced mRNA and protein expression levels of Nav channels in nodose neurons. In addition, using the whole‐cell patch‐clamp technique, we found that Nav current density and cell excitability of the aortic baroreceptor neurons were lower in CHF rats than that in sham rats. Aortic baroreflex sensitivity was blunted in anesthetized CHF rats, compared with that in sham rats. Furthermore, Nav channel activator (rATX II, 100 nM) significantly enhanced Nav current density and cell excitability of aortic baroreceptor neurons and improved aortic baroreflex sensitivity in CHF rats. These results suggest that reduced expression and activation of the Nav channels are involved in the attenuation of baroreceptor neuron excitability, which subsequently contributes to the impairment of baroreflex in CHF state. © 2010 Wiley‐Liss, Inc.
Simvastatin interferes with process outgrowth and branching of oligodendrocytes
Authors: Smolders Inge , Smets Ilse , Maier Olaf , vandeVen Martin , Steels Paul , Ameloot Marcel
Published: September 2010

Statins have attracted interest as a treatment option for multiple sclerosis (MS) because of their pleiotropic antiinflammatory and immunomodulatory effects. However, contradictory results have been described when they are applied to oligodendrocytes (OLGs), the cell type predominantly affected in MS. In this study we focus on the in vitro effect of statins on process outgrowth in OLN‐93 cells, a well‐characterized OLG‐derived cell line, and primary cultures of neonatal rat OLGs. Application of the lipophilic simvastatin, as low as 0.1–1 μM, disturbs process formation of both cell types, leading to less ramified cells. We show that both protein isoprenylation and cholesterol synthesis are required for the normal differentiation of OLGs. It is further demonstrated that the expression of 2′,3′‐cyclic‐nucleotide‐3′ phosphodiesterase (CNP) and tubulin is lowered, concomitant with a reduction of membrane‐bound CNP as well as tubulin. Therefore, we propose that lack of isoprenylation of CNP could help to explain the altered morphological and biochemical differentiation state of treated OLGs. Moreover, expression of specific myelin markers, such as myelin basic protein, myelin‐associated glycoprotein, and myelin oligodendrocyte glycoprotein, was compromised after treatment. We conclude that simvastatin treatment has detrimental effects on OLG process outgrowth, the prior step in (re)myelination, thereby mortgaging long‐term healing of MS lesions. © 2010 Wiley‐Liss, Inc.
Glial cell line‐derived neurotrophic factor enhances in vitro differentiation of mid‐/hindbrain neural progenitor cells to dopaminergic‐like neurons
Authors: Young Amber , Assey Kristin S. , Sturkie Carla D. , West Franklin D. , Machacek David W. , Stice Steven L.
Published: September 2010

Parkinson's disease (PD) affects the motor system through the degeneration of the dopaminergic neurons of the substantia nigra. The use of human embryonic stem cell (hESC)‐derived human neural progenitor (hNP) cells provides a potential cell source for cell therapies and drug screens for future treatments. Glial cell line‐derived neurotrophic factor (GDNF) is a known dopaminergic neuroprotectant agent; however, its potential role in neural differentiation remains largely unknown. Addition of 25 ng/ml GDNF to hNP cell differentiation media, over a 21‐day period, induced a significantly (P < 0.05) greater portion of hNP cells to differentiate into dopaminergic neurons than non‐GDNF cultures, 50% compared with 2.9% of cells expressing tyrosine hydroxylase (TH), respectively. The hNP cells exposed to GDNF selectively expressed dopamine receptors 1, 4, and 5 and were evoked to release dopamine with KCl. This is the first report of GDNF and leukemia inhibitory factor enriching hESC‐derived hNP cells toward dopaminergic‐like neurons. © 2010 Wiley‐Liss, Inc.
Post‐Plasma Grafting of AEMA as a Versatile Tool to Biofunctionalise Polyesters for Tissue Engineering
Authors: Desmet Tim , Billiet T. , Berneel Elke , Cornelissen Ria , Schaubroeck David , Schacht Etienne , Dubruel Peter
Published: September 2010

In the last decade, substantial research in the field of post‐plasma grafting surface modification has focussed on the introduction of carboxylic acids on surfaces by grafting acrylic acid (AAc). In the present work, we report on an alternative approach for biomaterial surface functionalisation. Thin poly‐ε‐caprolactone (PCL) films were subjected to a dielectric barrier discharge Ar‐plasma followed by the grafting of 2‐aminoethyl methacrylate (AEMA) under UV‐irradiation. X‐ray photoelectron spectroscopy (XPS) confirmed the presence of nitrogen. The ninhydrin assay demonstrated, both quantitatively and qualitatively, the presence of free amines on the surface. Confocal fluorescence microscopy (CFM), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to visualise the grafted surfaces, indicating the presence of pAEMA. Static contact angle (SCA) measurements indicated a permanent increase in hydrophilicity. Furthermore, the AEMA grafted surfaces were applied for comparing the physisorption and covalent immobilisation of gelatin. CFM demonstrated that only the covalent immobilisation lead to a complete coverage of the surface. Those gelatin‐coated surfaces obtained were further coated using fibronectin. Osteosarcoma cells demonstrated better cell‐adhesion and cell‐viability on the modified surfaces, compared to the pure PCL films.

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Calculation of Grafting and Property Characterization in Polyurethane‐Acrylic Hybrid Materials Prepared by Emulsion Process
Authors: Jiang Xubao , Kong Xiang‐Zheng , Zhu Xiaoli , Zhang Zhao , Zhang Zhi‐Guo
Published: September 2010

Polyurethane‐acrylics (PU‐AC) hybrid latexes were prepared using isophorone diisocyanate and polypropylene oxides as main monomers for the PU component, butyl acrylate and methyl methacrylate as AC monomers, and hydroxyethyl acrylate (HEA) as coupling agent to build up chemical bonds between PU prepolymers and AC polymers (PAC). A simple method to determine the PU grafted to PAC chains at one end and at both ends was established, which showed that PU grafted to PAC at both terminals was obviously increasing with HEA, and soon became predominant over that grafted by one end when the HEA/NCO molar ratio reached 0.67. With HEA/NCO < 1, PU grafting, particle size of the hybrid latex and film tensile strength increased with the HEA amount; while with HEA/NCO > 1, these properties remained relatively stable.

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BMO and Injectivity of Space Quasiregular Mappings
Authors: Martio Olli , Ryazanov Vladimir , Vuorinen Matti
Published: September 2010

It is shown that if the dilatation tensor G f of a space quasi regular mapping f belongs to the space VMO (vanishing mean oscillation), then f is a local homeomorphism. The same is true If the BMO‐norm of G f is small or if Gf is only close to the VMO space in the BMO‐norm.
Continuity of Edge and Corner Pseudodifferential Operators
Authors: Seiler Jorg
Published: September 2010

A theorem of Calderón‐Vaillancourt type is obtained for a class of pseudodifferential sparators with operator‐valued symbols, and strongly continuous (in general non‐smooth) groups If isomorphisms involved in the symbol estimates.
Remarks on Interpolation Properties of the Measure of Weak Non ‐‐ Compactness and Ideal Variations
Authors: Cobos Fernando , Martínez Antón
Published: September 2010

We estimate the ideal measure of certain interpolated operators in terms of the measure of their restrictions to the intersection. The dual situation is also studied. Special attention is paid to the ideal of weakly compact operators.
The Essential Spectrum of a System of Singular Ordinary Differential Operators of Mixed Order. Part I: The General Problem and an Almost Regular Case
Authors: Faierman Melvin , Mennicken Reinhard , Möller Manfred
Published: September 2010

A system of ordinary differential operators of mixed order on an interval (0,τ0), ro0 > 0, is considered, where the coefficients may be singular at 0. A special case has been dealt with by Kako where the essential spectrum of an operator associated with a linearized magnetohydrodynamic equation was explicitly calculated. In the present first part of the paper we study an almost regular special case which can be treated by the operator theoretical methods developed by Atkinson, Langer, Mennicken and Shkalikov. A closed linear operator is associated with the given system of differential operators and its essential spectrum is explicitly characterized in terms of the coefficients of these differential operators.
Real‐Time IR Study of Ultra‐Thin Film Photopolymerization of Liquid Porphyrin Monomer
Authors: Lintinen Kalle , Granqvist Niko , Efimov Alexander , Lemmetyinen Helge
Published: September 2010

By using an advanced polarization modulation infrared reflection adsorption spectroscopy (PM‐IRRAS) device it is possible to study the photopolymerization of an ultrathin layer of a porphyrin monomer in real time. The method can be compared with the indirect UV/Vis method previously introduced by our group. With PM‐IRRAS it is possible to analyze polymerization kinetics of photopolymerization at various temperatures to determine the activation energy of the reaction.

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Revisiting Chain Transfer to Polymer and Branching in Controlled Radical Polymerization of Butyl Acrylate
Authors: Reyes Yuri , Asua José M.
Published: September 2010

Acrylic monomers undergo chain transfer to polymer during polymerization leading to branched and even gelled polymers. It has been experimentally demonstrated that the extent of branching is higher for conventional free radical polymerization than for controlled radical polymerization (ATRP, RAFT, NMP) and this has been qualitatively explained in terms of the differences in the concentrations of highly reactive short‐chain radicals between controlled and conventional radical polymerizations. Contrary to this explanation, in this work, it is quantitatively demonstrated that the short transient lifetime of the radicals, i.e., the time between activation and deactivation of the radical in controlled radical polymerization, is the cause for the low level of branching in these polymerizations.

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Modeling Controlled/Living Radical Polymerization Kinetics: Bulk and Miniemulsion
Authors: Tobita Hidetaka
Published: September 2010

A first‐principle model for the controlled/living radical polymerization (CLRP) is discussed. The polymerization rate of CLRP is conveniently represented by a simple relationship, Rp ∝ [Intermediate]/[Trapping Agent], which highlights the important characteristics of various types of CLRPs. In stable free radical polymerization and atom‐transfer radical polymerization, the relationship, [Trap] ≪ [Interm] holds, and the polymerization rate is controlled by [Trap]. When the polymerization is conducted in nanosized particles, even a single trapping agent in a particle may lead to a larger [Trap] than for bulk polymerization. This single‐molecule‐concentration (SMC) effect theory leads to determine the particle diameter, Dp,SMC below which Rp starts to decrease significantly compared with the corresponding bulk polymerization, and $R_{{\rm p}} \,{\propto} \,D_{{\rm p}}^{3} $ for Dp < Dp,SMC. For the particle sizes somewhat larger than Dp,SMC, the statistical variation in the number of trapping agents can make Rp larger. A simple equation to estimate the Dp,Fluct‐value, below which the acceleration due to the fluctuation effect is predicted to occur, is presented. In conjunction with the SMC effect, an acceleration window, in which Rp is larger than for bulk polymerization, may be observed for Dp,SMC < Dp < Dp,Fluct. On the other hand, many reversible‐addition‐fragmentation chain transfer polymerizations conform to the condition [Interm] ≪ [Trap], and Rp is controlled by [Interm]. If [Interm] in a particle under the zero‐one condition is larger than for bulk polymerization, Rp can be increased significantly by reducing the particle size due to the zero‐one intermediate molecule (ZIM) effect. The ZIM effect theory leads to determine the particle diameter, Dp,ZIM below which Rp increases significantly compared with the bulk polymerization, and $R_{{\rm p}} \,{\propto} \,D_{{\rm p}}^{{-} 3} $ for Dp < Dp,ZIM.

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Compatibility of superparamagnetic iron oxide nanoparticle labeling for 1H MRI cell tracking with 31P MRS for bioenergetic measurements
Authors: Zhang Zhuoli , Hancock Brynne , Leen Stephanie , Ramaswamy Sharan , Sollott Steven J. , Boheler Kenneth R. , Juhaszova Magdalena , Lakatta Edward G. , Spencer Richard G. , Fishbein Kenneth W.
Published: September 2010

Labeling of cells with superparamagnetic iron oxide nanoparticles permits cell tracking by 1H MRI while 31P MRS allows non‐invasive evaluation of cellular bioenergetics. We evaluated the compatibility of these two techniques by obtaining 31P NMR spectra of iron‐labeled and unlabeled immobilized C2C12 myoblast cells in vitro. Broadened but usable 31P spectra were obtained and peak area ratios of resonances corresponding to intracellular metabolites showed no significant differences between labeled and unlabeled cell populations. We conclude that 31P NMR spectra can be obtained from cells labeled with sufficient iron to permit visualization by 1H imaging protocols and that these spectra have sufficient quality to be used to assess metabolic status. This result introduces the possibility of using localized 31P MRS to evaluate the viability of iron‐labeled therapeutic cells as well as surrounding host tissue in vivo. Published in 2010 by John Wiley & Sons, Ltd.
Molecular orientation behavior of mesomorphic isotactic polypropylene under uniaxial and biaxial deformation
Authors: Yoshida Shingo , Ishii Kazuomi , Kawamura Takanobu , Nitta Koh‐Hei
Published: September 2010

The molecular orientation behavior of mesomorphic isotactic polypropylene films under biaxial extension was investigated at room temperature. The birefringence was measured not only for drawn films but also simultaneously with biaxial stresses. It was found that there exists a yield point at which the neck is initiated on the biaxial deformed films and necking occurred and propagated in only one stretching direction, resulting in mosaic structures consisting of necked blocks. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Silane grafting and moisture crosslinking of polypropylene
Authors: Chaudhary Bharat Indu , Sengupta Saurav S. , Cogen Jeffrey M. , Curto Michael
Published: September 2010

Different approaches for free‐radical initiated grafting of functional monomers to polypropylene (PP) have been investigated with a view to enabling crosslinking of the polymer upon subsequent exposure to moisture, resulting in gel contents as high as 50–60 wt%. The first approach involved grafting a co‐agent such as triallyl trimellitate (TATM) to the polymer using peroxide initiator to add carbon–carbon double bond functionality to the polymer, followed by peroxide‐initiated grafting of mercaptopropyltrimethoxysilane (MPTMS) to the PP‐TATM adduct. The second approach was the more traditional peroxide‐mediated grafting of vinyltrimethoxysilane (VTMS) to polypropylene, and was most effective at increasing melt state dynamic storage modulus. In the third approach, peroxide‐mediated grafting of VTMS was followed by peroxide‐initiated grafting of MPTMS. This process took advantage of the unsaturation created via chain scission in the first step to provide graft sites for the MPTMS in the second step. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Sulfonated poly(bis‐A)‐sulfones as proton exchange membranes for direct methanol fuel cell application
Authors: He Shoulin , Yu Jianjia , Li Cuihua , Fang Jianhua , Xu Jing , Guan Rong
Published: September 2010

Sulfonated poly(bis‐A)‐sulfone (SPSF) samples were prepared by a mild postsulfonation method using trimethylsilyl chlorosulfonate as sulfonation agent, and their thermal and mechanical properties were evaluated. The serials of SPSF membranes are thermally stable up to 450°C in air. When compared with the poly(bis‐A)‐sulfone membrane, the hydrophilicity and water uptake of the SPSF membranes are enhanced. A microphase‐separated structure comprised of hydrophilic and hydrophobic polymer backbone was observed from atomic force microscopy phase images. The hydrophilic ionic clusters become continuous to form channels when ion exchange capacity (IEC) reached 1.47 mequiv/g. Moreover, the membranes showed very good proton conductivities (20°C, 0.01–0.11 S/cm) and low‐methanol permeability (0.09–3.06 × 10−6 cm2/s), and the methanol diffusion coefficients were lower than that of Nafion112 (1.35 × 10−6 cm2/s) with IEC values from 0.70 to 1.47 mequiv/g. However, the Fenton's reagent test revealed that the membranes exhibited very poor oxidation stability, which is the main defect limiting the application of SPSF for proton exchange membranes. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Interpenetrating polymer network of blocked polyurethane and phenolic resin. I. Synthesis, morphology, and mechanical properties
Authors: Sun Yun‐Yun , Chen Chin‐Hsing
Published: September 2010

Interpenetrating polymer networks (IPNs) based on blocked polyurethane (BPU)/phenolic (PF) were prepared using simultaneous polymerization method. The IPN was prepared from BPU prepolymer with m‐xylylenediamine as the chain extender and PF prepolymer using p‐toluene sulfonic acid as a catalyst. From Fourier transform infrared spectra analysis, it was found that the major reactions in the BPU/PF IPN system are the polymerization of BPU/MXDA and the self‐polymerization of PF. It was confirmed from scanning electron micrography that the BPU/PF IPN compatibility of the networks was improved, and the system was heterogeneous and more than one phase existed in the IPN. The tensile properties, flexural properties, impact, and hardness of the prepared IPN were studied. To obtain the best mechanical properties of IPN materials, the filler added in IPN materials has to be investigated. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
One‐step preparation of black polystyrene particles via in situ suspension polymerization
Authors: Yan Juntao , Miao Xiaojie , Zhang Qiaoyun , Cui Xuejun , Li Junfeng , Wang Hongyan
Published: September 2010

A facile one‐step technique of preparing black polystyrene (PS) was developed by in situ suspension polymerization in which polymerization of styrene was conducted in the presence of modified carbon black (CB). A series of uniform black PS particles had been synthesized with this method. Morphology and dispersion stability of the various CBs were investigated by both scanning electron microscopy and spectrophotometric analysis. The results of thermogravimetric analysis indicated that the thermal stability of PS was significantly enhanced by introducing modified CB. In addition, the PS synthesized in the absence or presence of modified CB possessed a narrow molecular distribution, as was characterized by gel permeation chromatography. Compared with the conventional mechanical blending technique of PS and CB, our present technique could not only avoid the drawback of poor miscibility between the CB and PS, but also simplify the synthesis technique. Scanning electron microscopy micrographs of the resulting black PS demonstrated that modified CB was well dispersed in the PS matrix. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers