bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lactide Polymerisation with Air‐Stable and Highly Active Zinc Complexes with Guanidine–Pyridine Hybrid Ligands
Authors: Börner Janna , Flörke Ulrich , Huber Klaus , Döring Artjom , Kuckling Dirk , Herres‐Pawlis Sonja 
Published: January 2009

AbstractNew class of air‐stable catalystsfor lactide polymerisation: Guanidine–pyridine hybrid ligands (picture, left) were used to prepare a series of zinc complexes (e.g., depicted cation [ZnL2(CF3SO3)]+, where L is the quinoline‐containing ligand with R1=R2=R3=R4=Me), in which the ligand binds through two different N‐donor atoms. The zinc complexes show high activity in ring‐opening polymerisation ofd,l‐lactide (right), giving polylactide with molecular masses up to 176 000 g mol−1and in high yield.magnified imageThe synthesis of zinc complexes of guanidine–pyridine hybrid ligands [Zn(DMEGpy)Cl2] (C1), [Zn(TMGpy)Cl2] (C2), [Zn(DMEGqu)Cl2] (C3), [Zn(TMGqu)Cl2] (C4), [Zn(DMEGpy)(CH3COO)2] (C5), [Zn(TMGpy)(CH3COO)2] (C6), [Zn(DMEGqu)(CH3COO)2] (C7), [Zn(TMGqu)(CH3COO)2] (C8), [Zn(DMEGqu)2(CF3SO3)][CF3SO3] (C9) and [Zn(TMGqu)2(CF3SO3)][CF3SO3] (C10) is reported. These zinc complexes were completely characterised and screened regarding their activity in the ring‐opening polymerisation ofd,l‐lactide. They proved to be active initiators in lactide bulk polymerisation, and polylactides with molecular weights (Mw) up to 176 000 g mol−1could be obtained. They combine high activity with robustness towards moisture and air. The influence of reaction temperature and of the anionic component of the zinc salt on the activity of the catalyst, as well as the occurrence of undesired side reactions, was investigated. By correlating these findings with the structural study on the zinc complexes we could deduce a structure–reactivity relationship for the zinc catalysts. This study was accompanied by DFT calculations. The bis‐chelate triflate complexesC9andC10, supported by quinoline–guanidine ligandsL3andL4, exhibit by far the highest reactivity. Systematic comparison of these complexes with their mono‐chelate counterparts and their bis‐guanidine analogues allows the attributes that promote polymerisation by neutral guanidine ligand systems to be elucidated: accessibility to the zinc centre and Lewis acidity.
Electrothermal stability of uniform arrays of one‐port elements
Authors: Storti‐Gajani Giancarlo , Premoli Amedeo , Brambilla Angelo 
Published: January 2009

AbstractPower electronic elements are often built employing arrays of devices designed to evenly share high currents over a large number of single devices. In some situations, mismatch in current sharing can occur causing temperature differences between elements of the array. These differences can trigger electrothermal instability phenomena and even device destruction. In this paper, we consider the electrothermal dynamic behavior of arrays composed of identical one‐port elements. We first introduce a simplified model of the thermal paths and of the elements composing the array that allows the analysis of the behavior of the electrothermal system. Then, we investigate from a mathematical standpoint dynamic effects governing current sharing and possible situations causing hot spots with consequent device destruction. These results are compared with simulations of detailed non‐linear models confirming predictions given by the simplified model. Copyright © 2008 John Wiley & Sons, Ltd.
A terminal‐controlled vertical handover decision scheme in IEEE 802.21‐enabled heterogeneous wireless networks
Authors: Wu Jung‐Shyr , Yang Shun‐Fang , Hwang Bor‐Jiunn 
Published: January 2009

AbstractThe seamless internetworking among heterogeneous networks is in great demand to provide ‘always‐on’ connectivity services with quality of service (QoS) provision, anywhere at anytime. The integration of wireless‐fidelity (Wi‐Fi) and wireless metropolitan area networks (WiMAX) networks can combine their best features to provide ubiquitous access, while mediating the weakness of both networks. While it is challenging to obtain optimized handover decision‐based dynamic QoS information, users can improve their perceived QoS by using the terminal‐controlled handover decision in a single device equipped with multiple radio interfaces. The IEEE 802.21 aims at providing a framework that defines media‐independent handover (MIH) mechanism that supports seamless handover across heterogeneous networks. In this paper, an multiple attributes decision making‐based terminal‐controlled vertical handover decision scheme using MIH services is proposed in the integrated Wi‐Fi and WiMAX networks to provide ‘always‐on’ connectivity QoS services. The simulation results show that the proposed scheme provides smaller handover times and lower dropping rate than the RSS‐based and cost function‐based vertical handover schemes. Copyright © 2009 John Wiley & Sons, Ltd.
Characterization of dendritic spines in the Drosophila central nervous system
Authors: Leiss Florian , Koper Ewa , Hein Irina , Fouquet Wernher , Lindner Jana , Sigrist Stephan , Tavosanis Gaia 
Published: January 2009

AbstractDendritic spines are a characteristic feature of a number of neurons in the vertebrate nervous system and have been implicated in processes that include learning and memory. In spite of this, there has been no comprehensive analysis of the presence of spines in a classical genetic system, such as Drosophila, so far. Here, we demonstrate that a subset of processes along the dendrites of visual system interneurons in the adult fly central nervous system, called LPTCs, closely resemble vertebrate spines, based on a number of criteria. First, the morphology, size, and density of these processes are very similar to those of vertebrate spines. Second, they are enriched in actin and devoid of tubulin. Third, they are sites of synaptic connections based on confocal and electron microscopy. Importantly, they represent a preferential site of localization of an acetylcholine receptor subunit, suggesting that they are sites of excitatory synaptic input. Finally, their number is modulated by the level of the small GTPase dRac1. Our results provide a basis to dissect the genetics of dendritic spine formation and maintenance and the functional role of spines. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009
Large‐scale rainfall simulation over shallow caves on karst shrublands
Authors: Gregory Lucas , Wilcox Bradford P. , Shade Bev , Munster Clyde , Owens Keith , Veni George 
Published: January 2009

AbstractWithin semi‐arid landscapes, karst areas are among the most productive in terms of water supply—largely because of the high rates of groundwater recharge compared with those of other semi‐arid areas. Recharge rates in karst regions may be affected by the type of vegetation cover. Understanding the interactions between recharge and vegetation is important at many levels, but the complex nature of karst hydrology makes this endeavour challenging. This paper presents the results of a set of hillslope‐scale rainfall simulation experiments conducted within a juniper–oak woodland and over a shallow karst cave that was instrumented for drip‐rate monitoring. The variables measured during these experiments include the amounts and timing of cave recharge, surface runoff, stemflow, and throughfall. The findings of this study provide insights into the importance of canopy interception during runoff‐producing events, the nature and relative magnitude of rapid recharge, and the interplay between recharge and surface runoff. Key findings of the study were (1) for simulated rainstorms of around 50 mm, between 0 and 23% of the water applied was intercepted (depending on cloud conditions), and 4–9% of the water reaching the ground surface came from stemflow (which was highest under the wettest conditions); (2) surface runoff accounted for approximately 3% of the water applied; and (3) recharge accounted for between 8 and 17% of the water applied and typically reached its maximum level within 20 min of rainfall cessation, declining rapidly thereafter. Copyright © 2009 John Wiley & Sons, Ltd.
Direct Aza‐Diels–Alder Reaction in Water Catalyzed by Layered α‐Zirconium Hydrogen Phosphate and Sodium Dodecyl Sulfate
Authors: Costantino Umberto , Fringuelli Francesco , Orrù Mara , Nocchetti Morena , Piermatti Oriana , Pizzo Ferdinando 
Published: January 2009

AbstractThe direct aza‐Diels–Alder reaction between 2‐cyclohexen‐1‐one (1) and benzaldimines 2 in water is reported for the first time. The reaction occurs at 30 °C, is catalyzed by layered α‐zirconium hydrogen phosphate (α‐ZrP) and requires the presence of sodium dodecyl sulfate (SDS). The reaction yield is excellent, the reaction is faster and the exo diastereoselectivity is higher than when organic solvent is used. The one‐pot, three‐component version of the reaction and the recycling of both the catalyst and the aqueous mother liquor in toto (water, α‐ZrP and SDS) have also been investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Symbolic threat and social dominance among liberals and conservatives: SDO reflects conformity to political values
Authors: Morrison Kimberly Rios , Ybarra Oscar 
Published: January 2009

AbstractThree studies tested the effects of symbolic threat to group values and strength of ingroup (political party) identification on social dominance orientation (SDO), a measure of tolerance for social hierarchies. In Studies 1 and 3, conservative participants were made to feel as though their group's values were either threatened or not threatened by liberals prior to completing the SDO measure. In Studies 2 and 3, liberal participants were made to feel as though their group's values were either threatened or not threatened by conservatives prior to completing the SDO measure. Results demonstrated that high ingroup (political party) identification was associated with high SDO scores for threatened conservatives, and with low SDO for threatened liberals. These findings suggest that in response to symbolic threat, SDO can shift in directions consistent with protecting the ingroup's identity. Copyright © 2009 John Wiley & Sons, Ltd.
Interference from Trace Copper in Electrochemical Investigations Employing Carboxylic Acid Terminated Thiol Modified Gold Electrodes
Authors: Qu Xiaohu , Bond Alan M. , Martin Lisandra L. 
Published: January 2009

AbstractUnexpectedly, electrochemistry at variable chain length carboxylic acid terminated alkylthiol self‐assembled monolayers (SAMs) on gold electrodes gives rise to a Faradaic process in buffered aqueous electrolyte solution. In particular, the three‐carbon chain length, 3‐mercaptopropionic acid (MPA), exhibits a chemically reversible process with a mid‐point potential of 175 mV vs. Ag/AgCl under conditions of cyclic voltammetry. This process is associated with the presence of trace (parts per billion) amounts of copper(II) ions present in the chemical reagents used to prepare the aqueous electrolyte and also from the gold electrode itself. The carboxylic acid moiety on the SAM concentrates Cu2+ ions by coordination and this surface confined layer is then reduced. Methods to minimize the interference of Cu2+ ions at carboxylic acid terminated SAM are discussed and caution with respect to the interpretation of protein electrochemistry is recommended when using carboxylic acid functionalized SAMs to provide biocompatible electrochemical transduction surfaces, unless a metal free environment can be obtained.
Psychiatric disorder as a first manifestation of cancer: A 10‐year population‐based study
Authors: Benros Michael E. , Laursen Thomas M. , Dalton Susanne O. , Mortensen Preben B. 
Published: January 2009

AbstractTo investigate the possibility that psychiatric symptoms could be caused by a yet undetected cancer or be part of a paraneoplastic syndrome, nationwide population‐based registers were linked including the Danish Psychiatric Central Register and the Danish Cancer Registry. Data were analysed as a cohort study using survival analysis techniques and incidence rate ratios (IRRs) were used as measures of relative risk. A total of 4,320,623 persons were followed in the 10‐year period 1994–2003, resulting in 37,581,600 person‐years at risk, 202,144 persons with a first‐time psychiatric contact, and 208,995 persons diagnosed with cancer. During the first month after a first‐time psychiatric contact, the incidence of all forms of cancer was elevated; IRR: 2.61 (95% CI, 2.31–2.95). Particularly the incidence of brain tumours was elevated; IRR: 18.85 (95% CI, 14.52–24.48), but also the incidence of lung cancer; IRR: 2.98 (95% CI, 2.16–4.12), and especially small‐cell lung cancer; IRR: 6.13 (95% CI, 3.39–11.07) was elevated. The elevated IRR for most cancers decreased towards unity within the first 3 months, except for brain tumours, for which the IRR remained significantly elevated during the first 9 months. One of every 63 patients above 50 years of age was diagnosed with malignant cancer within 1 year of first‐time psychiatric contact. These results indicate an increased incidence of cancer, especially for brain tumours and small‐cell lung cancer, in the first months after a first‐time contact to a psychiatric hospital. Clinicians should be aware that first‐onset psychiatric symptoms could be a sign of a yet undetected cancer. © 2009 UICC
Localization of nuclear cathepsin L and its association with disease progression and poor outcome in colorectal cancer
Authors: Sullivan Shane , Tosetto Miriam , Kevans David , Coss Alan , Wang Laimun , O'Donoghue Diarmuid , Hyland John , Sheahan Kieran , Mulcahy Hugh , O'Sullivan Jacintha 
Published: January 2009

AbstractPrevious in vitro studies have identified a nuclear isoform of Cathepsin L. The aim of this study was to examine if nuclear Cathepsin L exists in vivo and examine its association with clinical, pathological and patient outcome data. Cellular localization (nuclear and cytoplasmic) and expression levels v of Cathespin L in 186 colorectal cancer cases using immunohistochemistry. The molecular weight and activity of nuclear and cytoplasmic Cathepsin L in vivo and in vitro were assessed by Western blotting and ELISA, respectively. Epithelial nuclear staining percentage (p = 0.04) and intensity (p = 0.006) increased with advancing tumor stage, whereas stromal cytoplasmic staining decreased (p = 0.02). Using multivariate statistical analysis, survival was inversely associated with staining intensity in the epithelial cytoplasm (p = 0.01) and stromal nuclei (p = 0.007). In different colorectal cell lines and in vivo tumors, pro‐ and active Cathepsin L isoforms were present in both the cytoplasm and nuclear samples, with pro‐Cathepsin L at 50 kDa and active Cathepsin L at 25 kDa. Purified nuclear and cytoplasmic fractions from cell lines and tumors showed active Cathepsin L activity. The identification of nuclear Cathepsin L may play an important prognostic role in colorectal disease progression and patient outcome. Moreover, these findings suggest that altering active nuclear Cathepsin L may significantly influence disease progression. © 2009 UICC
Management of familial hypertriglyceridemia during pregnancy with plasma exchange
Authors: Sivakumaran Praveen , Tabak Steven W. , Gregory Kimberly , Pepkowitz Samuel H. , Klapper Ellen B. 
Published: January 2009

AbstractHypertriglyceridemia‐induced pancreatitis is a serious complication of familial dyslipidemias. Hormonal influences during pregnancy can compromise otherwise controlled lipid levels in women with familial hypertriglyceridemia and predispose to pancreatitis leading to increased morbidity in both mother and fetus. We report the successful use of therapeutic plasma exchange (TPE) in the management of hypertriglyceridemia during pregnancy resulting in avoidance of pancreatitis and delivery of a healthy term infant. Thirteen TPEs were performed from 19 to 36 weeks gestation to maintain tight control of triglyceride levels. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc.
Kaempferol induces apoptosis in two different cell lines via Akt inactivation, Bax and SIRT3 activation, and mitochondrial dysfunction
Authors: Marfe Gabriella , Tafani Marco , Indelicato Manuela , Sinibaldi‐Salimei Paola , Reali Valentina , Pucci Bruna , Fini Massimo , Russo Matteo Antonio 
Published: January 2009

AbstractKaempferol (3,4′,5,7‐tetrahydroxyflavone) is a flavonoid with anti‐ and pro‐oxidant activity present in various natural sources. Kaempferol has been shown to posses anticancer properties through the induction of the apoptotic program. Here we report that treatment of the chronic myelogenous leukemia cell line K562 and promyelocitic human leukemia U937 with 50 µM kaempferol resulted in an increase of the antioxidant enzymes Mn and Cu/Zn superoxide dismutase (SOD). Kaempferol treatment induced apoptosis by decreasing the expression of Bcl‐2 and increasing the expressions of Bax. There were also induction of mitochondrial release of cytochrome c into cytosol and significant activation of caspase‐3, and ‐9 with PARP cleavage. Kaempferol treatment increased the expression and the mitochondria localization of the NAD‐dependent deacetylase SIRT3. K562 cells stably overexpressing SIRT3 were more sensitive to kaempferol, whereas SIRT3 silencing did not increase the resistance of K562 cells to kaempferol. Inhibition of PI3K and de‐phosphorylation of Akt at Ser473 and Thr308 was also observed after treating both K562 and U937 cells with kaempferol. In conclusion our study shows that the oxidative stress induced by kaempferol in K562 and U937 cell lines causes the inactivation of Akt and the activation of the mitochondrial phase of the apoptotic program with an increase of Bax and SIRT3, decrease of Bcl‐2, release of cytochrome c, caspase‐3 activation, and cell death. J. Cell. Biochem. 106: 643–650, 2009. © 2009 Wiley‐Liss, Inc.
Inactivation of 14‐3‐3 σ by promoter methylation correlates with metastasis in nasopharyngeal carcinoma
Authors: Yi Bin , Tan Shuang‐Xiang , Tang Can‐E , Huang Wei‐Guo , Cheng Ai‐Lan , Li Cui , Zhang Peng‐Fei , Li Mao‐Yu , Li Jian‐Ling , Yi Hong , Peng Fang , Chen Zhu‐Chu , Xiao Zhi‐Qiang 
Published: January 2009

Abstract14‐3‐3 σ, the downstream target of p53, is a negative regulator of cell cycle G2‐M phase checkpoint in response to DNA damage. Our previous comparative proteomics study showed that 14‐3‐3 σ was downregulated or lost in nasopharyngeal carcinoma (NPC) tissue compared with non‐cancerous nasopharyngeal epithelial tissue (NNET). In this study, we further investigated for the epigenetic mechanism of 14‐3‐3 σ inactivation. Methylation‐specific PCR showed 14‐3‐3 σ promoter methylation in 100% of analyzed NPC cell lines (4/4) but not in immortalized human nasopharyngeal epithelial cell line NP69. Treatment of the four NPC cell lines with the methyltransferase inhibitor 5‐aza‐2′‐dC resulted in the demethylation and upregulation of 14‐3‐3 σ. In tissues, 14‐3‐3 σ promoter methylation occurred at a higher frequency in NPC, 63/75 (84%), compared to adjacent NNET, 7/25 (28%), and fully methylated 14‐3‐3 σ promoter was detected in NPC but not in any of adjacent NNET. RT‐PCR, Western blotting, and immunohistochemistry showed that 14‐3‐3 σ expression was downregulated or lost in NPC with methylation, and there was a negative correlation between the expression levels and methylation statuses of 14‐3‐3 σ gene. In addition, the patients with methylated 14‐3‐3 σ presented a higher frequency of lymph node and distant metastasis, and an advanced clinical stage, and overexpression of 14‐3‐3 σ in NPC cell line 5‐8F with high metastatic potential was able to inhibit its in vitro invasive ability. Our data are the first to show that 14‐3‐3 σ is frequently inactivated by promoter methylation in NPC and this aberrant methylation correlates with lymph node and distant metastasis. J. Cell. Biochem. 106: 858–866, 2009. © 2009 Wiley‐Liss, Inc.
Differential expression of nuclear matrix proteins during the differentiation of human neuroblastoma SK‐N‐SH cells induced by retinoic acid
Authors: Liang Ying , Li Qi‐Fu , Zhang Xiu‐Yan , Shi Song‐Lin , Jing Guang‐Jun 
Published: January 2009

AbstractTo investigate the alteration of nuclear matrix proteins (NMPs) during the differentiation of neuroblastoma SK‐N‐SH cells induced by retinoic acid (RA), differentiation markers were detected by immunocytochemistry and NMPs were selectively extracted and subjected to two‐dimensional gel electrophoresis analysis. Immunocytochemical observation demonstrated that the expression of neuronal markers was up‐regulated in SK‐N‐SH cells following RA treatment. Meanwhile, 52 NMPs (41 of which were identified) changed significantly during SK‐N‐SH differentiation; four of these NMPs were further confirmed by immunoblotting. This study suggests that the differentiation of neuroblastoma cells was accompanied by the altered expression of neuronal markers and NMPs. The presence of some differentially expressed NMPs was related to the proliferation and differentiation of neuroblastomas. Our results may help to reveal the relationship between NMPs and neuroblastoma carcinogenesis and reversion, as well as elucidate the regulatory principals driving neural cell proliferation and differentiation. J. Cell. Biochem. 106: 849–857, 2009. © 2009 Wiley‐Liss, Inc.
Expression profiles of SV40‐immortalization‐associated genes upregulated in various human cancers
Authors: Jung Hyun Min , Choi Seong‐Jun , Kim Jin Kyeoung 
Published: January 2009

AbstractImmortalization is an early and essential step of human carcinogenesis which is associated with alterations in gene expression and regulation. Suppression subtractive hybridization (SSH) was successfully performed to identify immortalization‐associated genes upregulated in SV40‐immortalized lung fibroblasts. We identified 116 known genes which were related to diverse functions, with 32.8% relevant for cell cycle or proliferation indicating the potential involvement of these genes in immortalization. We chose eight known genes located on the overrepresented chromosomes of non‐small‐cell lung cancers (NSCLCs). ASPM, RFC4, C3orf26, BXDC2, C15orf44, AURKA, C20orf77, and RBMX were upregulated in immortalized cells, cancer cells, and non‐small‐cell lung cancer (NSCLC) tissues. We additionally cloned two novel genes (CHA‐V‐97 and CHA‐V‐165) which showed similar upregulated expression patterns in cells and tissues examined. Identification and further characterization of these genes may provide insights of novel players for immortalization and human carcinogenesis. J. Cell. Biochem. 106: 703–713, 2009. © 2009 Wiley‐Liss, Inc.
Hypoxia or in situ normoxia: The stem cell paradigm
Authors: Ivanovic Zoran 
Published: January 2009

AbstractAlthough O2 concentrations are considerably lowered in vivo, depending on the tissue and cell population in question (some cells need almost anoxic environment for their maintenance) the cell and tissue cultures are usually performed at atmospheric O2 concentration (20–21%). As an instructive example, the relationship between stem cells and micro‐environmental/culture oxygenation has been recapitulated. The basic principle of stem cell biology, “the generation‐age hypothesis,” and hypoxic metabolic properties of stem cells are considered in the context of the oxygen‐dependent evolution of life and its transposition to ontogenesis and development. A hypothesis relating the self‐renewal with the anaerobic and hypoxic metabolic properties of stem cells and the actual O2 availability is elaborated (“oxygen stem cell paradigm”). Many examples demonstrated that the cellular response is substantially different at atmospheric O2 concentration when compared to lower O2 concentrations which better approximate the physiologic situation. These lower O2 concentrations, traditionally called “hypoxia” represent, in fact, an in situ normoxia, and should be used in experimentation to get an insight of the real cell/cytokine physiology. The revision of our knowledge on cell/cytokine physiology, which has been acquired ex vivo at non physiological atmospheric (20–21%) O2 concentrations representing a hyperoxic state for most primate cells, has thus become imperious. J. Cell. Physiol. 219: 271–275, 2009. © 2009 Wiley‐Liss, Inc.