bluuebunny/crossref_metadata_2025 huggingface dataset:
Titanacalixarenes in Homogeneous Catalysis: Synthesis, Conformation and Catalytic Activity in Ethylene Polymerisation
Authors: Espinas Jeff , Darbost Ulrich , Pelletier Jeremie , Jeanneau Erwan , Duchamp Christian , Bayard François , Boyron Olivier , Broyer Jean‐Pierre , Thivolle‐Cazat Jean , Basset Jean‐Marie , Taoufik Mostafa , Bonnamour Isabelle
Published: February 2010

Variously substituted titanacalixarenes were synthesised and tested for their performance as catalysts in ethylene polymerisation: p‐tert‐butylcalix[4]arene was derivatised to afford distal diether p‐tert‐butylcalix[4]arenes L1–L4, distal dihydroxy‐depleted L5, proximal dihydroxy‐depleted L6, proximal diether p‐tert‐butylcalix[4]arene L7, proximal intrabridged disiloxane L8 and proximal monoether L9. (Dichlorotitana)‐p‐tert‐butylcalix[4]arenes 1–8 and (monochlorotitana)‐p‐tertbutylcalix[4]arene 9 have been successfully synthesised by reacting L1–L4 with TiCl4·2THF or L5–L9 with TiCl4. The structural conformation of complexes 1–9 in solution were determined by 1H NMR, 13C NMR, NOESY and COSY spectroscopic studies. Compounds 2, 3 and 4 have been structurally characterised by single‐crystal X‐ray diffraction. Upon activation with methylaluminoxane, compounds 1–8 revealed low to moderate activities for the production of high‐density polyethylene (HDPE) to ultra‐high‐molecular‐weight polyethylene (UHMWPE). 6/MAO gave the best activity at 770 kgPE (mol Ti)–1 h–1.
Palladium‐Catalyzed Intramolecular Aryl Amination Reaction: An Expeditious Approach to the Synthesis of Chiral Benzodiazocine Derivatives
Authors: Adhikary Nirmal Das , Chattopadhyay Partha
Published: February 2010

A palladium‐catalyzed method for intramolecular amination of aryl bromides and iodides has been developed employing different bulky biaryl phosphanes as ligands and toluene as solvent. A variety of electron‐rich aryl halide substrates have been aminated by the intramolecular pathway in good yield using different sugar‐derived amines as well as benzylamine. The method is capable of furnishing benzodiazocines in chiral form besides dibenzodiazocine derivatives of potential biological interest.
Simultaneous Determination of Hydroquinone and Catechol at an Activated Glassy Carbon Electrode
Authors: Ahammad A. J. Saleh , Sarker Subrata , Rahman Md Aminur , Lee Jae‐Joon
Published: February 2010

A selective and very simple electrochemical method, based on anodization of a glassy carbon electrode (GCE), was developed for the simultaneous detection of hydroquinone (HQ) and catechol (CT). It was found that the activated GCE showed an excellent catalytic behavior and enhanced reversibility towards the oxidation of both HQ and CT. The redox responses from the mixture of HQ and CT were easily resolved at an activated GCE. The detection limits for HQ and CT were calculated to be 0.16 and 0.11 μM, respectively. The activated GCE was successfully examined for real sample analysis with tap water and it showed a stable and reliable recovery data.
Determination of the Apparent Michaelis Constant of Glucose Oxidase Immobilized on a Microelectrode with Respect to Oxygen
Authors: Yasukawa Tomoyuki , Goto Keisuke , Mizutani Fumio
Published: February 2010

We report determination of the apparent Michaelis constant of glucose oxidase (GOx) immobilized on a microelectrode with respect to oxygen. We used a GOx‐modified microelectrode as a probe for scanning electrochemical microscopy. We detected hydrogen peroxide generated by the enzyme reaction at the microelectrode under controlling the oxygen concentration using water electrolysis at an interdigitated array (IDA) electrode. The response depends on the oxygen concentration, which is regulated by the microelectrode position and the potential applied to the IDA electrode. We estimated the apparent Michaelis constant with respect to oxygen in this experimental condition to be about 0.28 mM.
Achiral and chiral separations using MEKC, polyelectrolyte multilayer coatings, and mixed mode separation techniques with molecular micelles
Authors: Luces Candace A. , Warner Isiah M.
Published: February 2010

Mixed mode (MM) separation using a combination of MEKC and polyelectrolyte multilayer (PEM) coatings is herein reported for the separation of achiral and chiral analytes. Many analytes are difficult to separate by MEKC and PEM coatings alone. Therefore, the implementation of a MM separation provides several advantages for overcoming the limitations of these well‐established methods. In this study, it was observed that achiral separations using MEKC and PEM coatings individually resulted in partial resolution of eight very similar aryl ketones when the molecular micelle (sodium poly(N‐undecanoyl‐L‐glycinate)) concentration was varied from 0.25 to 1.00% w/v and the bilayer number varied from 2 to 4. However, when MM separation was introduced, baseline resolution was achieved for all eight analytes. In the case of chiral separations, temazepam, aminoglutethimide, benzoin, benzoin methyl ether, and coumachlor were separated using the three separation techniques. For chiral separations, the chiral molecular micelle, sodium poly(N‐undecanoyl‐L‐leucylvalinate), was employed at concentrations of 0.25–1.50% w/v for both MEKC and PEM coatings. Overall, the results revealed partial separation with MEKC and PEM coatings individually. However, MM separation enabled baseline separation of each chiral mixture. The separation of achiral and chiral compounds from different compound classes demonstrates the versatility of this MM approach.
Analysis of phenolic xenoestrogens by pressurized CEC with amperometric detection
Authors: Wu Weimin , Yuan Xiaomei , Wu Xiaoping , Lin Xucong , Xie Zenghong
Published: February 2010

A new method, pressurized CEC with end‐column amperometric detection using carbon paste electrode, has been developed for the separation and determination of five phenolic xenoestrogens in chicken eggs and milk powder samples. Efficient separation of five analytes was performed by pressurized CEC using a mobile phase consisting of 60% v/v ACN and 40% v/v Tris buffer (5 mmol/L, pH 8.0), +6 kV of applied voltage and 7.0 MPa of supplementary pressure. Detection limits of 50, 5, 2, 10 and 20 ng/mL for pentachlorophenol, bisphenol‐A, 2,4‐dichlorophenol, 4‐tert‐octylphenol and 4‐nonylphenol, respectively, were achieved using carbon paste electrode as working electrode and +0.8 V as detection potential. Matrix solid phase dispersion extraction method had been employed during sample preparation procedure, and mean recoveries ranged from 79.2 to 102.6% at different concentrations of phenolic xenoestrogens for spiked egg and milk powder samples were obtained.
Some examples of the communication of risk and uncertainty
Authors: Brillinger David R.
Published: February 2010

Definitions are set down and results of analyses of communication of risk and uncertainty are presented for the fields of wildfires, earthquakes and space debris. These are all fields of some societal importance. Also there is discussion of methods of evaluating and displaying estimates of risk estimates' uncertainty. Copyright © 2010 John Wiley & Sons, Ltd.
Relevance of octanol–water distribution measurements to the potential ecological uptake of multi-walled carbon nanotubes
Authors: Petersen Elijah J. , Huang Qingguo , Weber Walter J.
Published: February 2010

Many potential applications of carbon nanotubes (CNTs) require various physicochemical modifications prior to use, suggesting that nanotubes having varied properties may pose risks in ecosystems. A means for estimating bioaccumulation potentials of variously modified CNTs for incorporation in predictive fate models would be highly valuable. An approach commonly used for sparingly soluble organic contaminants, and previously suggested for use as well with carbonaceous nanomaterials, involves measurement of their octanol–water partitioning coefficient (KOW) values. To test the applicability of this approach, a methodology was developed to measure apparent octanol–water distribution behaviors for purified multi-walled carbon nanotubes and those acid treated. Substantial differences in apparent distribution coefficients between the two types of CNTs were observed, but these differences did not influence accumulation by either earthworms (Eisenia foetida) or oligochaetes (Lumbriculus variegatus), both of which showed minimal nanotube uptake for both types of nanotubes. The results suggest that traditional distribution behavior-based KOW approaches are likely not appropriate for predicting CNT bioaccumulation. Environ. Toxicol. Chem. 2010;29:1106–1112. © 2010 SETAC
Schwann cell migration is integrin‐dependent and inhibited by astrocyte‐produced aggrecan
Authors: Afshari Fardad T. , Kwok Jessica C. , White Linda , Fawcett James W.
Published: February 2010

Schwann cells transplantation has considerable promise in spinal cord trauma to bridge the site of injury and for remyelination in demyelinating conditions. They support axonal regeneration and sprouting by secreting growth factors and providing a permissive surface and matrix molecules while shielding axons from the inhibitory environment of the central nervous system. However, following transplantation Schwann cells show limited migratory ability and they are unable to intermingle with the host astrocytes. This in turn leads to formation of a sharp boundary and an abrupt transition between the Schwann cell graft and the host tissue astrocytes, therefore preventing regenerating axons from exiting the graft. The objective of this study was to identify inhibitory elements on astrocytes involved in restricting Schwann cell migration. Using in vitro assays of cell migration, we show that aggrecan produced by astrocytes is involved in the inhibition of Schwann cell motility on astrocytic monolayers. Knockdown of this proteoglycan in astrocytes using RNAi or digestion of glycosaminglycan chains on aggrecan improves Schwann cell migration. We further show aggrecan mediates its effect by disruption of integrin function in Schwann cells, and that the inhibitory effects of aggrecan can overcome by activation of Schwann cell integrins. © 2010 Wiley‐Liss, Inc.
Triptolide promotes spinal cord repair by inhibiting astrogliosis and inflammation
Authors: Su Zhida , Yuan Yimin , Cao Li , Zhu Yanling , Gao Liang , Qiu Yang , He Cheng
Published: February 2010

Spinal cord injury (SCI) is a cause of major neurological disability, and no satisfactory treatment is currently available. Traumatic SCI directly damages the cell bodies and/or processes of neurons and triggers a series of endogenous processes, including neuroinflammatory response and reactive astrogliosis. In this study, we found that triptolide, one of the major active components of the traditional Chinese herb Tripterygium wilfordii Hook F, inhibited astrogliosis and inflammation and promoted spinal cord repair. Triptolide was shown to prevent astrocytes from reactive activation by blocking the JAK2/STAT3 pathway in vitro and in vivo. Furthermore, astrocytic gliosis and glial scar were greatly reduced in injured spinal cord treated with triptolide. Triptolide treatment was also shown to decrease the ED‐1 or CD11b‐positive inflammatory cells at the lesion site. Using neurofilament staining and anterograde tracing, a significantly greater number of regenerative axons were observed in the triptolide‐treated rats. Importantly, behavioral tests revealed that injured rats receiving triptolide had improved functional recovery as assessed by the Basso, Beattie, and Bresnahan open‐field scoring, grid‐walk, and foot‐print analysis. These results suggested that triptolide promoted axon regeneration and locomotor recovery by attenuating glial scaring and inflammation, and shed light on the potential therapeutic benefit for SCI. © 2010 Wiley‐Liss, Inc.
Genetic ablation of steroid receptor coactivator‐3 promotes PPAR‐β‐mediated alternative activation of microglia in experimental autoimmune encephalomyelitis
Authors: Xiao Yichuan , Xu Jingwei , Wang Shu , Mao Chaoming , Jin Min , Ning Guang , Xu Jianming , Zhang Yanyun
Published: February 2010

Steroid receptor coactivator‐3 (SRC‐3) has been demonstrated to regulate lipid metabolism by inhibiting adipocyte differentiation. In this study, the potential role of SRC‐3 in experimental autoimmune encephalomyelitis (EAE), which characterized by inflammatory demyelination in central nervous system (CNS), was examined by analyzing disease progression in SRC‐3‐deficient (SRC‐3−/−) mice. We found that SRC‐3 deficiency significantly attenuated the disease severity of EAE along with decreased inflammatory infiltration and demyelination. However, these effects are not caused by inhibition of peripheral T cell response, but by upregulated expression of peroxisome proliferator‐activated receptor (PPAR)‐β in CNS, which induced an alternative activation state of microglia in SRC‐3−/− mice. These alternatively activated microglia inhibited CNS inflammation through inhibition of proinflammatory cytokines and chemokines, such as TNF‐α, IFN‐γ, CCL2, CCL3, CCL5, and CXCL10, as well as upregulation of anti‐inflammatory cytokine IL‐10 and opsonins, such as C1qa and C1qb. Moreover, microglia alternative activation promoted myelin regeneration through increased accumulation of oligodendrocyte precursors in white matter and elevated expression of myelin genes in the spinal cords of SRC‐3−/− mice. Our results build up a link between lipid metabolic regulation and immune functions, and the modulation of the expression of SRC‐3 or PPAR‐β may hopefully has therapeutic modality in MS and possibly other neurodegenerative diseases. © 2010 Wiley‐Liss, Inc.
An Fgfr3‐iCreERT2 transgenic mouse line for studies of neural stem cells and astrocytes
Authors: Young Kaylene M. , Mitsumori Tomoyuki , Pringle Nigel , Grist Matthew , Kessaris Nicoletta , Richardson William D.
Published: February 2010

The lack of markers for astrocytes, particularly gray matter astrocytes, significantly hinders research into their development and physiological properties. We previously reported that fibroblast growth factor receptor 3 (Fgfr3) is expressed by radial precursors in the ventricular zone of the embryonic neural tube and subsequently by differentiated astrocytes in gray and white matter. Here, we describe an Fgfr3‐iCreERT2 phage artificial chromosome transgenic mouse line that allows efficient tamoxifen‐induced Cre recombination in Fgfr3‐expressing cells, including radial glial cells in the embryonic neural tube and both fibrous and protoplasmic astrocytes in the mature central nervous system. This mouse strain will therefore be useful for studies of normal astrocyte biology and their responses to CNS injury or disease. In addition, Fgfr3‐iCreERT2 drives Cre recombination in all neurosphere‐forming stem cells in the adult spinal cord and at least 90% of those in the adult forebrain subventricular zone. We made use of this to show that there is continuous accumulation of all major interneuron subtypes in the olfactory bulb (OB) from postnatal day 50 (P50) until at least P230 (∼8 months of age). It therefore seems likely that adult‐born interneurons integrate into existing circuitry and perform long‐term functions in the adult OB. © 2010 Wiley‐Liss, Inc.
Vav‐1 expression correlates with NFκB activation and CD40‐mediated cell death in diffuse large B‐cell lymphoma cell lines
Authors: Hollmann Annette , Aloyz Raquel , Baker Kristi , Dirnhofer Stephan , Owens Trevor , Sladek Robert , Tzankov Alexandar
Published: February 2010

Diffuse large B‐cell lymphoma (DLBCL) is an aggressive malignancy with a variable response to therapy. We have previously shown that DLBCL cell lines differ in their susceptibility to CD40‐mediated cell death, and that resistance to CD40‐targeted antibodies correlated with increased expression of markers of immature B‐cell and absence of Vav‐1 mRNA. We used gene expression profiling to investigate the mechanism of CD40 resistance in these cell lines, and found that resistance correlated with lack of Vav‐1 and inability to activate NFκB upon CD40 ligation. Analysis of tissue microarrays of 213 DLBCL cases revealed that Vav‐1 expression correlated with a higher proliferative index and the presence of the post‐germinal centre marker Irf‐4. Our results suggest that Vav‐1 expression may be associated with activated B‐cell DLBCL origin and higher proliferative activity, and indicate Vav‐1 as a potential marker to identify tumours likely to respond to CD40‐targeted therapies. Copyright © 2010 John Wiley & Sons, Ltd.
Leaf Quality of Some Tropical and Temperate Tree Species as Food Resource for Stream Shredders
Authors: Graça Manuel A. S. , Cressa Claudia
Published: February 2010

We tested the hypotheses that (1) plant defenses against consumers increase in the tropics, and that these differences in quality are perceived by detritivores; and (2) microbial conditioning of leaf litter is important for the feeding ecology of shredders from both geographical regions. We compared quality parameters of 8 tree species from Portugal and 8 from Venezuela. The tropical leaves were tougher, but did not differ from temperate leaves in terms of N, C: N, and polyphenols. In multiple‐choice experiments, shredders from Portugal (Sericostoma vittatum and Chaetopteryx lusitanica) and from Venezuela (Nectopsyche argentata and Phylloicus priapulus) discriminated among conditioned leaves, preferentially consuming softer leaves. In another set of experiments, all shredders preferentially fed on conditioned rather than unconditioned leaves, grew faster when fed conditioned than unconditioned leaves and fed more on temperate than tropical leaves. We conclude that leaf litter from the tropics is a low‐quality resource compared to leaves in temperate systems, because of differences in toughness, and that tropical shredders benefit from microbial colonization, as previously demonstrated for temperate systems. We suggest that leaf toughness could be one explanation for the reported paucity of shredders in some tropical streams. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Zn, Fe and Mn on Leaf Litter Breakdown by Aquatic Fungi: a Microcosm Study
Authors: Medeiros Adriana , Duarte Sofia , Pascoal Cláudia , Cássio Fernanda , Graça Manuel
Published: February 2010

We investigated the effects of heavy metals on leaf litter decomposition in streams. Leaves were immersed (10 days) at a reference (R) and a metal‐impacted (I) site and exposed in microcosms with increased Zn, Mn or Fe content, and to stream water from site R or I. Fungal biomass was higher in microcosms with leaves colonized at I and water from R. Fungal sporulation was higher in microcosms with leaves and water from R. Concentrations of 4.9, 9.6 and 5 ppm of Zn, Mn and Fe decrease fungal sporulation. The number of fungal species (spore counts and DGGE fingerprints) was lower in leaves colonized at site I. Cluster analyses of DGGE showed that Fe was the metal that most altered the structure of fungal community. Our results suggest that metal pollution affect leaf‐associated fungi depending on metal identity and concentration, and effects appear to be less pronounced in metal‐adapted communities. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Involvement of Src‐suppressed C kinase substrate in experimental autoimmune encephalomyelitis: A link between release of astrocyte proinflammatory factor and oligodendrocyte apoptosis
Authors: Li Xiaohong , Yan Meijuan , Hu Ling , Sun Linlin , Zhang Fupeng , Ji Huoyan , Jiang Jing , Wang Ping , Liu Haiou , Gao Ying , Tao Tao , He Xingxin , Cheng Chun , Shen Aiguo
Published: February 2010

Src‐suppressed C kinase substrate (SSeCKS) is involved in inflammation in the central nervous system (CNS), and plays a role in control of cell signaling and cytoskeletal arrangement. However, the expression and function of SSeCKS and its function in multiple sclerosis (MS) and its common animal model, experimental autoimmune encephalomyelitis (EAE) remained to be elucidated. In the present study, we first reported that SSeCKS was remarkably increased in astrocytes of EAE rats in vivo. TNF‐α and NO were significantly induced in astrocytes stimulated with LPS/IFN‐γ in vitro, which was blocked in astrocytes transfected with SSeCKS siRNA. These results indicated that SSeCKS played a role in the production of TNF‐α and NO in astrocytes with inflammatory stimulation. As excessive release of TNF‐α and NO were major mediators in autoimmune diseases and correlated with oligodendrocyte cell death, we further investigated whether SSeCKS participated in oligodendrocyte apoptosis. Conditioned media (CM) from astrocytes treated with LPS/IFN‐γ decreased oligodendrocyte cell viability, while siRNA targeted to SSeCKS in astrocytes inhibited oligodendrocyte cell death. The results from antibody neutralization and NO inhibition suggested that the oligodendrocyte apoptosis may be due to the production of astrocyte‐derived proinflammatory factors (TNF‐α and NO). These findings revealed that there was a pathogenic interaction between SSeCKS expression in astrocytes and oligodendrocyte apoptosis. Understanding the mechanism of SSeCKS in the pathogenesis of EAE may contribute to the development of new therapeutic strategies against EAE and MS. © 2010 Wiley‐Liss, Inc.
Regulation of cholesterol efflux by amyloid β secretion
Authors: Umeda Tomohiro , Mori Hiroshi , Zheng Hui , Tomiyama Takami
Published: February 2010

Amyloid β (Aβ) is a key molecule in the pathogenesis of Alzheimer's disease, but its physiological function remains unclear. Aβ is produced from amyloid precursor protein (APP) by β‐ and γ‐secretases, which is enhanced by high levels of cellular cholesterol, so cholesterol is a risk factor for Alzheimer's disease. This linkage led us to hypothesize that Aβ is produced to regulate cellular cholesterol levels in response to high‐cholesterol stimulation. Here we show that Aβ production caused a reduction of cellular cholesterol levels in transfected HEK293 cells and neuronal IMR‐32 and Neuro2a cells, which was accompanied by an increase in efflux of cholesterol from cells. Fractionation of the culture media by ultracentrifugation and subsequent immunoelectron microscopic observation revealed that Aβ assembled high‐density lipoprotein‐like particles with cellular cholesterol during its secretion. This assembly was mediated by the ATP‐binding cassette transporter A1. APP transgenic and knockout mice exhibited lower and higher levels of cellular cholesterol in their brains, suggesting that Aβ‐mediated regulation of cellular cholesterol is physiological. Furthermore, we found that, when injected into mouse cerebral ventricle, reconstituted lipoproteins with Aβ were excreted into the peripheral tissues more efficiently than those without Aβ. This result suggests that Aβ mediates cholesterol transport from the brain to the circulation. We propose, based on these findings, a novel, apolipoprotein‐like function for Aβ that is involved in maintenance of cellular and cerebral cholesterol homeostasis. © 2010 Wiley‐Liss, Inc.
Chronic foot‐shock stress potentiates the influx of bone marrow‐derived microglia into hippocampus
Authors: Brevet Marie , Kojima Hideto , Asakawa Akihiro , Atsuchi Kaori , Ushikai Miharu , Ataka Koji , Inui Akio , Kimura Hiroshi , Sevestre Henri , Fujimiya Mineko
Published: February 2010

For several years, a new population of microglia derived from bone marrow has been described in multiple settings such as infection, trauma, and neurodegenerative disease. The aim of this study was to investigate the migration of bone marrow‐derived cells to the brain parenchyma after stress exposure. Stress exposure was performed in mice that had received bone marrow transplantation from GFP mice, allowing identification of blood‐derived elements within the brain. Electric foot‐shock exposure was chosen because of its ability to serve as fundamental and physical stress in mice. Bone marrow‐derived GFP+ cells migrated to the ventral part of the hippocampus and acquired a ramified microglia‐like morphology. Microglia marker Iba1 was expressed by 100% of the ramified cells, whereas ramified cells were negative for the astrocyte marker GFAP. Compared with the case in the control group, ramified cells significantly increased after chronic exposure to stress (5 days). One month after 5 days of stress exposure, ramified cells significantly decreased in ventral hippocampus compared with the group examined immediately after the last stress exposure. We report for the first time the migration of bone marrow‐derived cells to the ventral hippocampus after stress exposure. These cells have the characteristics of microglia. Mechanisms responsible for this migration and their roles in the brain remain to be determined. © 2010 Wiley‐Liss, Inc.
Elevation of heme oxygenase‐1 by proteasome inhibition affords dopaminergic neuroprotection
Authors: Yamamoto Noriyuki , Izumi Yasuhiko , Matsuo Takaaki , Wakita Seiko , Kume Toshiaki , Takada‐Takatori Yuki , Sawada Hideyuki , Akaike Akinori
Published: February 2010

Postmortem studies have shown that heme oxygenase‐1 (HO‐1) immunoreactivity is increased in patients with Parkinson disease. HO‐1 expression is highly upregulated by a variety of stress. Since the proteasome activity is decreased in patients with Parkinson disease, we investigated whether proteasome activity regulates HO‐1 content. MG‐132, a proteasome inhibitor, increased the amount of HO‐1 protein mainly in astrocytes of primary mesencephalic cultures. Quantitative RT‐PCR analysis revealed that lactacystin upregulated HO‐1 mRNA expression. Proteasome inhibition with MG132 also increased the cytomegalovirus promoter‐driven expression of Flag‐HO‐1 protein and resulted in an accumulation of ubiquitinated Flag‐HO‐1 in Flag‐HO‐1‐overexpressing PC12 cells. In addition, a cycloheximide chase assay demonstrated that the degradation of Flag‐HO‐1 protein was slowed by MG‐132. Next, the function of HO‐1 which was upregulated by proteasome inhibitors was examined. Proteasome inhibitors protected dopaminergic neurons from 6‐hydroxydopamine (6‐OHDA)‐induced toxicity and this neuroprotection was abrogated by co‐treatment with zinc protoporphyrin IX, a HO‐1 inhibitor. Furthermore, 6‐OHDA‐induced toxicity was blocked by bilirubin and carbon monoxide, products of the HO‐1‐catalyzed degradation of heme. These results suggest that mesencephalic HO‐1 protein level is regulated by proteasome activity and the elevation by proteasome inhibition affords neuroprotection. © 2010 Wiley‐Liss, Inc.
Tieg1/Klf10 is upregulated by NGF and attenuates cell cycle progression in the pheochromocytoma cell line PC12
Authors: Spittau Gabriele , Happel Nicole , Behrendt Maik , Chao T. Ivo , Krieglstein Kerstin , Spittau Björn
Published: February 2010

The transcription factor Tieg1/Klf10 belongs to a family of Sp1/Klf proteins that have been shown to play important roles during development and maintenance of various tissues and cell types. Upregulation of Tieg1/Klf10 has been reported for TGF‐β, BMP2, BMP4, ActivinA and GDNF as members of the TGF‐β superfamily. Moreover, estrogen, the cytostatic drugs homoharringtonine and velcade as well as nitric oxide are also able to trigger Tieg1/Klf10 transcription. Recent studies suggest a role for members of the neurotrophin family in regulating Tieg1/Klf10 transcriptional upregulation. Using semi‐quantitative RT‐PCR and immunoblotting, we present data describing that nerve growth factor (NGF) regulates the expression of Tieg1/Klf10 in the pheochromocytoma cell line PC12 in a TrkA‐dependent manner. Moreover, we provide evidence for the existence of NGF‐responsive elements in the 5′‐regulatory region of Tieg1/Klf10 that contain binding sites for the transcription factors Sp1 and CREB. After treatment with NGF PC12 cells exit the cell cycle and start to differentiate towards a neuron‐like phenotype indicated by neurite outgrowth. Using flow cytometry and differentiation assays we demonstrate that Tieg1/Klf10 reduces cell cycle progression in PC12 cells but fails to promote their terminal differentiation. Together, our results identify Tieg1/Klf10 as a new NGF target gene and substantiate its anti‐proliferative function in the NGF signaling pathway in PC12 cells. © 2010 Wiley‐Liss, Inc.
Inflammation‐induced preterm birth alters neuronal morphology in the mouse fetal brain
Authors: Burd Irina , Bentz Amy I. , Chai Jinghua , Gonzalez Juan , Monnerie Hubert , Le Roux Peter D. , Cohen Akiva S. , Yudkoff Marc , Elovitz Michal A.
Published: February 2010

Adverse neurological outcome is a major cause of long‐term morbidity in ex‐preterm children. To investigate the effect of parturition and inflammation on the fetal brain, we utilized two in vivo mouse models of preterm birth. To mimic the most common human scenario of preterm birth, we used a mouse model of intrauterine inflammation by intrauterine infusion of lipopolysaccharide (LPS). To investigate the effect of parturition on the immature fetal brain, in the absence of inflammation, we used a non‐infectious model of preterm birth by administering RU486. Pro‐inflammatory cytokines (IL‐10, IL‐1β, IL‐6 and TNF‐α) in amniotic fluid and inflammatory biomarkers in maternal serum and amniotic fluid were compared between the two models using ELISA. Pro‐inflammatory cytokine expression was evaluated in the whole fetal brains from the two models. Primary neuronal cultures from the fetal cortex were established from the different models and controls in order to compare the neuronal morphology. Only the intrauterine inflammation model resulted in an elevation of inflammatory biomarkers in the maternal serum and amniotic fluid. Exposure to inflammation‐induced preterm birth, but not non‐infectious preterm birth, also resulted in an increase in cytokine mRNA in whole fetal brain and in disrupted fetal neuronal morphology. In particular, Microtubule‐associated protein 2 (MAP2) staining was decreased and the number of dendrites was reduced (P < 0.001, ANOVA between groups). These results suggest that inflammation‐induced preterm birth and not the process of preterm birth may result in neuroinflammation and alter fetal neuronal morphology. © 2010 Wiley‐Liss, Inc.
RP‐thin layer chromatographic method for the quantification of three gingerol homologs of ultrasonic‐assisted fresh rhizome extracts of Zingiber officinale collected from North Western Himalayas
Authors: Khan Imran , Pandotra Pankaj , Gupta Ajai Prakash , Sharma Rajni , Gupta Bishan Das , Dhar Jagdish Kumar , Ram Gandhi , Bedi Yashbir Singh , Gupta Suphla
Published: February 2010

A rapid and sensitive RP high‐performance thin‐layer chromatographic (RP‐HPTLC) methodology was developed and validated for the quantitative estimation of gingerols in methanolic extract of fresh ginger rhizome. The samples were chromatographed on RP‐TLC glass plates pre‐coated with RP‐18 60F254 as the stationary phase. Linear ascending development was carried out in twin trough glass chamber saturated with ternary‐solvent system consisting of acetonitrile–water–formic acid (7:2:1 v/v/v) at room temperature (25±2°C) and plates were scanned at 500 nm. The system was found to give compact spots for gingerols (Rf values of 6‐gingerol 0.73±0.04, 8‐gingerol 0.59±0.08 and 10‐gingerol 0.36±0.05). Linearity was found to be in the range of 140–840 ng/spot for 6‐gingerol, 168–1008 ng/spot for 8‐gingerol and 136–816 ng/spot for 10‐gingerol with significantly high value of correlation coefficient. The linear regression analysis data for the calibration plots showed linear relationship (r2) and ranged from 0.9992 to 0.9937 for 6‐, 8‐ and 10‐gingerol. The method was used for routine analyses and to obtain relative amounts of the gingerols in the fresh rhizomes of the ginger cultivated in different locations of Uttarakhand and Himachal Pradesh of North Western Himalayas (India).
Comparison of HPLC and CZE methods for analysis of DOTA‐like esters – reaction intermediates in synthesis of magnetic resonance contrast agents
Authors: Hamplová Anna , Křížek Tomáš , Kubíček Vojtěch , Bosáková Zuzana , Coufal Pavel
Published: February 2010

RP‐HPLC and non‐aqueous CZE methods were evaluated for qualitative and quantitative analysis of esterified macrocyclic compounds of the DOTA family (DOTA=1,4,7,10‐tetraazacyclododecan‐1,4,7,10‐tetraacetic acid). This group of compounds represents important reaction intermediates in synthesis of magnetic resonance contrast agents. Calibration curves in the concentration range from 1.0×10−5 to 1.0×10−3 mol/L were plotted and the experimental data were critically compared in terms of their repeatability, linearity, LOD and LOQ. The optimized methods were successfully applied to the analysis of a real reaction mixture without any further pretreatment.
Focusing of anionic micelles using sample‐induced transient isotachophoresis: Computer simulation and experimental verification in MEKC
Authors: Foteeva Lidia S. , Huang Zhuo , Timerbaev Andrei R. , Hirokawa Takeshi
Published: February 2010

The specific phenomenon of high‐salt micelle focusing used as a preconcentration method for uncharged solutes in MEKC has been interpreted in terms of complementary transient isotachophoresis (tITP) process. High matrix chloride can focus anionic SDS micelles not only due to a field‐enhanced effect but also by creating the tITP state in which chloride acts as a leading ion. The latter micelle‐enrichment event was simulated by SIMUL software in order to understand tITP conditions under which micelle stacking can be expected to occur. Specifically, effects of chloride matrix concentration and the nature of BGE co‐ion, performing a role of terminating ion, were explored. A greater extent of micelle stacking was observed at a higher chloride concentration in borate than in phosphate buffer system. This proof‐of‐principle simulation result was confirmed in real experiments using metal‐based chemotherapeutic drugs. It was concluded that analyte enrichment requires prolonged interaction with the micelle, which is feasible at a proper ratio between sample matrix and BGE co‐ion concentrations.
The relationship between tourism receipts, real effective exchange rate and economic growth in Tunisia
Authors: Belloumi Mounir
Published: February 2010

The objective of this paper is to analyse the role of tourism in the Tunisian economic growth. We used a trivariate model of real gross domestic product (GDP), real international tourism receipts and real effective exchange rate to discuss the relationship between tourism and economic growth. By using annual data for Tunisia for the period of 1970–2007, our results reveal that there is a cointegrating relationship between tourism and economic growth. In addition, our results for the Granger causality test indicate that tourism has a positive impact on GDP growth unidirectionally. Copyright © 2010 John Wiley & Sons, Ltd.
Electronic Properties and Photovoltaic Performances of a Series of Oligothiophene Copolymers Incorporating Both Thieno[3,2‐b]thiophene and 2,1,3‐Benzothiadiazole Moieties
Authors: Biniek Laure , Chochos Christos L. , Hadziioannou Georges , Leclerc Nicolas , Lévêque Patrick , Heiser Thomas
Published: February 2010

A series of donor‐acceptor alternated conjugated copolymers, composed of thiophene, bithiophene, thieno[3,2‐b]thiophene, and 2,1,3‐benzothiadiazole units and differing from each other by the nature and the number of 3‐alkylthiophene in the backbone, have been synthesized by Stille cross‐coupling polymerization. The material's optical and electrochemical properties, in solution and in thin films, have been investigated using UV‐Visible absorption and cyclic voltammetry. Bulk heterojunction solar cells using blends of the newly synthesized copolymers, as electron donor, and C60‐PCBM or C70‐PCBM, as electron transporting material, have been elaborated. A maximum power conversion efficiency of 1.8% is achieved with a 1:4 PPBzT2‐C12:C70‐PCBM weight ratio.

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Modular Synthesis and Electronic and Hole‐Transport Properties of Monodisperse Oligophenothiazines
Authors: Müller Thomas J. J. , Franz Adam W. , Barkschat (née Krämer) Christa S. , Sailer Markus , Meerholz Klaus , Müller David , Colsmann Alexander , Lemmer Uli
Published: February 2010

Summary: Monodisperse oligophenothiazines are rapidly synthesized in good yields by use of Suzuki arylation. These well defined oligomers reveal both highly fluorescence and low oxidation potentials. As a consequence of intense electronic coupling as supported by cyclic voltammetry a selected trimer shows hole‐transport properties in a hole‐conductor‐only set‐up of a diode with relatively low on‐set voltage.
Intelligent Hydrogels Via Gamma‐Ray Induced Polymerization of Micellar Monomer Solutions and Microemulsions
Authors: Friedrich Tatjana , Tieke Bernd
Published: February 2010

Summary: Intelligent hydrogels were prepared upon polymerization of micellar aqueous comonomer solutions and microemulsions containing the cationic surfactant monomer 11‐acryloyloxyundecyltrimethylammonium bromide (AUTMAB) and N‐isopropylacrylamide (NIPAM). A chemically and physically cross‐linked network structure is formed consisting of blocks of P‐NIPAM and P‐AUTMAB. The P‐AUTMAB blocks act as physical cross‐linking units improving the mechanical stability of the gel. While pure P‐NIPAM hydrogels are disrupted under low compression, gels polymerized from micellar solution or microemulsion can be reversibly compressed. The presence of AUTMAB in the gel increases the swelling up to a factor of 30 compared with the pure P‐NIPAM gel. Rapid and reversible swelling is observed for hydrogels with an AUTMAB content up to 2.5 wt.‐%.
Ion‐selective Membranes Prepared Upon Layer‐by‐Layer Assembly of Azamacrocycles and Polyelectrolytes
Authors: Hoffmann Kristina , El‐Hashani Ashraf , Tieke Bernd
Published: February 2010

Summary: Recent studies on ion transport across multilayered membranes of azamacrocycles and polyelectrolytes are reviewed. Membranes were built up on porous PAN/PET supports using electrostatic layer‐by‐layer assembly. Two types of separation membranes were prepared, type I consisting of protonated hexaazacyclooctadecane and polyvinylsulfate, and type II of hexaazacyclo‐octadecane hexaacetic acid and protonated polyvinylamine. Ion transport was studied under dialysis, nanofiltration and reverse osmosis conditions. Type I membranes were suitable for efficient separation of mono‐ and divalent anions, whereas type II membranes were suited for separation of mono‐ from di‐ and trivalent cations.
Water‐Soluble Polymers and Their Polymer‐Metal Ion‐Complexes as Antibacterial Agents
Authors: Rivas Bernabé L. , Maureira N. Antonio , Guzmán S. Catherine
Published: February 2010

Summary: Natural and synthetic polymers with heteroatom, such as oxygen, nitrogen, sulfur or phosphorous, potentially can efficiently remove metal ions from aqueous solutions. The ability of synthetic polymers derived from imino diacetic acid, acrylamido glycolic copolymer, and the natural polymer alginic acid to remove metal ions from dilute solution in conjunction with ultrafiltration membranes was studied. The maximum retention capacity was determined and its polymer‐metal ion‐complexes were studied as possible antibacterial agents.
Ultrasound‐Triggered Release of Ibuprofen from a Chitosan‐Mesoporous Silica Composite‐ a Novel Approach for Controlled Drug Release
Authors: Depan Dilip , Saikia Lakshi , Singh Raj Pal
Published: February 2010

Summary: In this work, an attempt was made to synthesize a novel Chitosan‐Mesoporous silica (CS‐MS) hybrid composite to design a drug delivery system based on ultrasound triggered stimuli‐responsive smart release. The in‐vitro drug release properties of both the Mesoporous Silica (MS) and Chitosan (CS) hybrids were investigated. Ibuprofen (Ibu) was used as a model drug. The results from powder X‐Ray diffraction (XRD) patterns, and BET N2 adsorption isotherms exhibited that MS can accommodate drug molecules into the lumen of the channels and pores. Drug release, stimulated by temperature and pH of the release media was also investigated. We studied the Ultrasound (US) triggered release of Ibu in a simulated body fluid (pH 7.4). The results exhibited that US can be used as a non‐invasive technique for drug release from polymeric materials. The enhancing effect of ultrasound on drug release is due to the Cavitation effect, without causing any significant destruction on the polymer morphology.
Isolation of a Dosage Dependent Lethal Mutation in Ubiquitin Gene of Saccharomyces Cerevisiae
Authors: Prabha C. Ratna , Mishra Pradeep , Shahukar Mitali
Published: February 2010

Summary: Ubiquitin is a small protein with a highly conserved sequence, playing a pivotal role in ubiquitin proteasome system (UPS). Considering the central role UPS has in cellular homeostasis, several drugs have been developed to target UPS to remove cells responsible for cancer and other neurodegenerative diseases. As an alternative to the above approach, in the present study we have isolated dose dependent lethal form of ubiquitin gene by in vitro evolution. In vitro evolution is a powerful tool for developing proteins with novel and desirable properties. The ubiquitin gene of Saccharomyces cerevisiae was subjected to in vitro evolution and lethal mutations were selected. The ubiquitin of S. cerevisiae differs only by three residues from human ubiquitin. The mutants were selected by expressing the protein in temperature sensitive ubi4 deletion mutants of ubiquitin. Most of the mutations in ubiquitin gene failed to complement UBI4 phenotype under heat shock. Only one of the mutants caused cell lysis, even at permissive temperature. Interestingly, expression of the same protein in wild type S. cerevisiae cells left them unaffected, establishing the mutant protein as a competitive inhibitor for UPS. Sequencing of the mutant gene showed four completely novel amino acid substitutions. They are namely, Ser20 to Phe, Ala46 to Ser, Leu50 to Pro and Ile61 to Thr. Construction of the mutant ubiquitin gene and characterization of the mutant phenotype along with the nature and location of the mutations are presented.
Aging of Polyimides in High Temperature Environments
Authors: Wieneke Jan U. , Staudt Claudia
Published: February 2010

Summary: Membranes made of high permeable fluorinated aromatic polyimide synthesized from 6FDA (4,4'‐hexafluoroisopropylidene diphthalic anhydride) and 4MPD (2,3,5,6‐tetramethyl‐1,4‐phenylene diamine) have been thermally treated to examine their aging behaviour at high temperature. The aging process was investigated by means of gas permeation tests, IR spectroscopy and thermogravimetric analysis combined with mass spectral analysis of the gaseous decomposition products. Up to around 400 °C thin films of the material show no major degradation but changes in color, flexibility and separation characteristics for O2/N2 were observed.
Crystallization and Physical Ageing of Poly (2‐vinyl pyridine)‐b‐poly(ethylene oxide) Diblock Copolymers
Authors: Córdova Miguel , Lorenzo Arnaldo T. , Müller Alejandro J. , Fragouli Panagiota , Iatrou Hermis , Hadjichristidis Nikos
Published: February 2010

Summary:A set of melt miscible Poly(2‐vinyl pyridine)‐b‐Poly(ethylene oxide) (P2VP‐b‐PEO) block copolymers of different compositions were studied. Transmission electron microscopy shows phase separation in the materials during the crystallization process of the PEO block as crystalline lamellae are observed for all compositions evaluated. The isothermal crystallization kinetics of PEO is progressively retarded as the P2VP content in the copolymer increases, since P2VP hinders molecular mobility in the miscible amorphous phase. Polarized light optical microscopy demonstrated that the glassy P2VP block has a negative effect on the secondary nucleation of the PEO. Finally, physical ageing experiments performed in the glassy state of the amorphous mixed phase, at different ageing times, demonstrated that a nucleating effect can be induced in the glassy state as a consequence of the reorganization of the amorphous regions. This nucleating effect significantly alters the cold crystallization rate upon subsequent heating above the glass transition temperature.
Influence of the Operative Conditions on the Characteristics of Poly(D,L‐lactide‐co‐glycolide) Synthesized in Supercritical Carbon Dioxide
Authors: Mazarro R. , de Lucas A. , Cabezas L. I. , Gracia I. , Rodríguez J. F.
Published: February 2010

Summary: The co‐polymerizations of D,L‐lactide and glycolide in supercritical carbon dioxide (scCO2) using zinc (II) ethylhexanoate (ZnOct2) as catalyst and methanol as initiator have been investigated. The influence of stirring rate (N), temperature (T), and mass carbon dioxide (mCO2) on molecular weight distribution (MWD); co‐polymer composition; and conversion has been studied by means an experimental factorial design. The stirring rate has the greatest influence on conversion. Due to the heterogeneous nature of the process the mass transfer enhancement, that the grater turbulence produces, favors greatly the incorporation of monomers into the polymer phase. An important decrease of molecular weight is observed independently of reaction conditions for high conversion values because some thermal degradation or rearrangement reactions are taking place. The influence of the initiator, methanol, on the molecular weight has been also studied. Methanol acts as an effective chain transfer agent initiating more growing chains than expected, what also contributes to get low molecular weights.
Novel Functional Mesoporous Materials Obtained from Nanostructured Diblock Copolymers
Authors: Gorzolnik Blazej , Davidson Patrick , Beurroies Isabelle , Denoyel Renaud , Grande Daniel
Published: February 2010

Summary: Novel carboxy (COOH)‐functionalized mesoporous polystyrene membranes were prepared from polystyrene‐block‐poly(D,L‐lactide) (PS‐b‐PLA) diblock copolymers through the selective degradation of the PLA block. The combination of atom transfer radical polymerization (ATRP) and ring‐opening polymerization (ROP) techniques enabled the synthesis of nanostructured diblock copolymers possessing carboxylic acid functionality at the junction between both blocks. Such copolymers were subjected to shear flow through the use of a channel die to align their nanodomains. Under mild alkaline conditions, the quantitative hydrolysis of the polyester nanodomains afforded mesoporous materials with COOH‐coated pore walls. The PS‐b‐PLA precursors as well as the resulting porous systems were carefully analyzed by size exclusion chromatography (SEC), 1H NMR, scanning electron microscopy (SEM), and two‐dimensional small‐angle X‐ray scattering (2‐D SAXS). Moreover, the specific surface area and pore size distribution were determined by nitrogen sorption porosimetry.
CVD Growth of Carbon Nanotubes and Nanofibers: Big Length and Constant Diameter
Authors: Toubestani D. Hanifeh , Ghoranneviss M. , Mahmoodi A. , Zareh M. Rahbar
Published: February 2010

Summary: We report mass production of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) with relatively high length and aspect ratio. We synthesized carbon nanomaterials by chemical vapor deposition (CVD) of methane as the feeding gas on Fe/Mo nanoparticles that use alumina‐aerogel support. Alumina‐aerogel‐supported Fe/Mo catalyst was prepared using sol‐gel. Drying step performed using rotary evaporation and freeze‐drying. CVD was performed using a quartz tube furnace. Samples were analyzed using scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Raman spectroscopy.