bluuebunny/crossref_metadata_2025_split huggingface dataset:
New anion exchanger organic–inorganic hybrid materials and membranes from a copolymerof glycidylmethacrylate and γ‐methacryloxypropyl trimethoxy silane
Authors: Wu Yonghui , Wu Cuiming , Gong Ming , Xu Tongwen 
Published: August 2006

AbstractOrganic–inorganic hybrid materials and mem branes were prepared through coating on Teflon plate or dip‐coating on microporous alumina substrates with the solution of glycidylmethacrylate (GMA) and γ‐methacryloxypropyl trimethoxy silane (γ‐MPS) copolymer, followed by ring‐opening of the GMA moiety with trimethylamine hydrochloric and sol–gel reaction of the γ‐MPS moiety. Composition of the GMA and γ‐MPS copolymer was varied by changing the feed ratio of GMA to γ‐MPS during the copolymerization. So the thermal stability, hydrophilicity, electrical properties, etc. of the hybrid materials and membranes were varied. Results showed that as the γ‐MPS amount increased in the copolymer, Td (the temperature on thermogram at 5% weight loss) value of the hybrid materials and water contact angle of the hybrid membrane generally increased, while the anion exchange capacity, water uptake (WR) and pure water flux decreased. The charge transition point of the hybrid membranes deduced from their streaming potential behavior decreased from pH > 12 to pH = 7–8 as the γ‐MPS amount increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3580–3589, 2006
Optimal combinational quota‐share and excess‐of‐loss reinsurance policies in a dynamic setting
Authors: Zhang Xin , Zhou Ming , Guo Junyi 
Published: August 2006

AbstractIn this paper, we describe a large insurance company's surplus by a Brownian motion with positive drift, which is the approximation of a classical risk process. The problem of minimizing the probability of ruin by controlling the combinational quota‐share and excess‐of‐loss reinsurance strategy is considered. We show that the optimal combinational reinsurance strategy must be the pure excess‐of‐loss reinsurance strategy. Moreover, we give an explicit solution for the optimal reinsurance strategy. Copyright © 2006 John Wiley & Sons, Ltd.
20S proteasomes and protein degradation “by default”
Authors: Asher Gad , Reuven Nina , Shaul Yosef 
Published: August 2006

AbstractThe degradation of the majority of cellular proteins is mediated by the proteasomes. Ubiquitin‐dependent proteasomal protein degradation is executed by a number of enzymes that interact to modify the substrates prior to their engagement with the 26S proteasomes. Alternatively, certain proteins are inherently unstable and undergo “default” degradation by the 20S proteasomes. Puzzlingly, proteins are by large subjected to both degradation pathways. Proteins with unstructured regions have been found to be substrates of the 20S proteasomes in vitro and, therefore, unstructured regions may serve as signals for protein degradation “by default” in the cell. The literature is loaded with examples where engagement of a protein into larger complexes increases protein stability, possibly by escaping degradation “by default”. Our model suggests that formation of protein complexes masks the unstructured regions, making them inaccessible to the 20S proteasomes. This model not only provides molecular explanations for a recent theoretical “cooperative stability” principle, but also provokes new predictions and explanations in the field of protein regulation and functionality. BioEssays 28: 844–849, 2006. © 2006 Wiley Periodicals, Inc.
Shugoshin and PP2A, shared duties at the centromere
Authors: Rivera Teresa , Losada Ana 
Published: August 2006

AbstractSister chromatid cohesion mediated by the ring‐shaped cohesin complex is essential for faithful chromosome segregation. A tight spatial and temporal control of cohesin release is observed in mitosis and meiosis, and a family of proteins known as shugoshins play a major role in this process. Shugoshin (Sgo) protects centromeric cohesin from dissociation in early mitosis and from cleavage by separase in meiosis I. Three exciting new reports indicate that this is accomplished by recruiting the serine/threonine protein phosphatase 2A (PP2A) to centromeres.(1–3) The proposed targets of PP2A activity include cohesin and Sgo, both of which would otherwise dissociate from chromosomes upon phosphorylation by Polo kinase. Thus, a balance of kinase and phosphatase activities seems to be the key to the conserved mechanism that regulates the stepwise release of cohesin from mitotic and meiotic chromosomes. Additional evidence, however, suggests that this is only part of the story, and that Sgo has also a role independent of PP2A. BioEssays 28: 775–779, 2006. © 2006 Wiley Periodicals, Inc.
Film‐forming process and biocide assessment of high‐molecular‐weight chitosan as determined by combined ATR‐FTIR spectroscopy and antimicrobial assays
Authors: Fernandez‐Saiz P. , Ocio M. J. , Lagaron J. M. 
Published: August 2006

AbstractThis pioneering study reported about the film‐forming properties of high‐molecular‐weight chitosan as followed in situ by attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy, and has implications in fields such as biomedical, pharmaceutical, packaging, and coating applications. From the results, it was observed that immediately after dissolution in an acetic acid aqueous solution and subsequent casting over the ATR crystal, the formed carboxylate antimicrobial (NH−OOCH) species are not stable in the film formulation and become reduced over time; further assays confirmed previous research, which suggested that the presence and stability of these groups is strongly dependent, among other factors, on storage conditions. As‐received chitosan and chitosan neutralized in NaOH films did not exhibit biocide performance towards Staphylococcus aureus. The antimicrobial tests were also found to strongly relate the presence of a sufficient quantity of these carboxylate groups to the chitosan activity as a biocide agent. Moreover, a novel methodology based on the use of a normalized infrared band centered at 1405 cm−1 is proposed which can be correlated with the antimicrobial character of the biopolymer. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 577–583, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Methylenetetrahydrofolate reductase C677T polymorphism in patients with gastric and colorectal cancer
Authors: Zeybek Umit , Yaylim İlhan , Yilmaz Hulya , Ağaçhan Bedia , Ergen Arzu , Arikan Soykan , Bayrak Savaş , İsbir Turgay 
Published: August 2006

AbstractThis study was designed to investigate, in the Turkish population, an association of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of gastric and colorectal cancer. Our study was carried out in 35 patients with gastric cancer (20 men, 15 women) and 144 controls (75 men, 69 women) and 52 colorectal cancer (31 men, 21 women). MTHFR C677T genotypes were determined by polymerase chain reaction, restriction fragment length polymorphism techniques. No differences were observed in the distribution of MTHFR genotypes or allele frequencies in cases versus controls. The homozygous mutation (T/T) in the MTHFR gene was identified in 14.3% of gastric cancer versus 10.4% of controls. MTHFR C677T frequencies of the CC, CT and TT genotypes among colorectal cancer patients were 34.6%, 51.9% and 13.5%, respectively. MTHFR C677T polymorphism may not be important in an individual's susceptibility to gastric and colorectal cancer in Turkey and may not be a useful marker for identifying patients at high risk of developing gastric and colorectal cancer. Copyright © 2006 John Wiley & Sons, Ltd.
The potential antioxidant effect of raloxifene treatment: a study on heart, liver and brain cortex of ovariectomized female rats
Authors: Konyalioglu Sibel , Durmaz Guliz , Yalcin Ayfer 
Published: August 2006

AbstractThe antioxidant activity of some compounds buffer the free radicals generated either endogenously or exogenously, thus decreasing the potential damage mediated by oxidation. Recent studies documented that raloxifene has antioxidant propertiesin vitro. However, there are limited animal studies available to show raloxifene's antioxidant properties. We aimed to investigate the effects of raloxifene on antioxidant enzymes such as SOD, CAT and GPX, TrxR and the levels of GSH and MDA in heart, liver and brain cortex of ovariectomized female rats. Female Sprague Dawley rats weighing 300–350 g (n = 24) were divided into three groups: (I) Eight non‐ovariectomized rats were used as naive controls without any treatment (non‐ovariectomized group,n = 8). Five weeks after ovariectomy, (II) Ovariectomized placebo group (n = 8) was given physiological saline, and (III) Raloxifene group (n = 8) was given raloxifene 1 mg/kg sc. daily for 12 days. Ovariectomy induced significant increases on SOD, GPX, CAT activity and MDA levels in brain, heart and liver tissues compared to non‐ovariectomized rats ( p < 0.05). Raloxifene treatment led to decreased levels of SOD activity in heart, GPX activity in brain and CAT activity in liver tissue when compared to ovariectomized group ( p < 0.05) but there was no change in activity of TrxR in all groups. The levels of MDA in brain, heart and liver tissues increased in ovariectomized group when compared to non‐overiectomized rats ( p < 0.05). Raloxifene had a significant attenuating effect on the levels of MDA in brain and heart tissues. Our results also indicate that the levels of GSH in brain, heart and liver tissue decreased when compared to non‐ovariectomized rats. Raloxifene treatment was observed to significantly increase the levels of GSH in brain and heart tissues ( p < 0.05). However, there were insignificant differences for the GSH levels in liver tissues of ovariectomized placebo or raloxifene groups. In conclusion, our results demonstrate that raloxifene may be more effective against oxidative stress in heart and brain than in liver tissue. Copyright © 2006 John Wiley & Sons, Ltd.
Efficacy of piperine, an alkaloidal constituent from Piper nigrum on erythrocyte antioxidant status in high fat diet and antithyroid drug induced hyperlipidemic rats
Authors: Vijayakumar Ramasamy Subramaniam , Nalini Namasivayam 
Published: August 2006

AbstractThe main aim of this study was to investigate the effect of piperine on erythrocyte antioxidant status in high fat diet (HFD) and antithyroid drug induced hyperlipidemic rats. Male Wistar rats were divided into eight groups. The first four groups were fed a control diet and in addition were given respectively 1% carboxymethyl cellulose (CMC); 10 mg/kg body weight carbimazole (CM); 10 mg CM + 40 mg/kg body weight piperine and 10 mg CM + 2 mg/kg body weight atorvastatin (ATV). A similar pattern was followed for the next four groups except that they were all fed HFD instead of the control diet. Erythrocyte osmotic fragility, total cholesterol, phospholipids, lipid peroxidation products, enzymic and non‐enzymic antioxidant status were studied in all experimental groups. Significantly increased osmotic fragility, total cholesterol/phospholipid ratio, thiobarbituric acid reactive substances and lipid hydroperoxides were observed in the plasma and erythrocytes of HFD fed and CM treated rats compared to the control. Superoxide dismutase, catalase, glutathione peroxidase, vitamin E and reduced glutathione in erythrocytes and vitamin C in the plasma were also significantly lowered in HFD fed, antithyroid drug treated rats compared to control animals. Concurrent piperine supplementation along with HFD and antithyroid drug administration normalized erythrocyte osmotic fragility, reduced lipid peroxidation, and improved the enzymic and non‐enzymic antioxidant status compared to those rats that did not receive piperine. Thus, our results indicate that piperine supplementation markedly protects erythrocytes from oxidative stress by improving the antioxidant status in HFD fed antithyroid drug treated rats. Copyright © 2006 John Wiley & Sons, Ltd.
Expression and activity of mTOR and its substrates in different cell cycle phases and in oral squamous cell carcinomas of different malignant grade
Authors: Liu Yi , Hidayat Sujuta , Su Wen‐hui , Deng Xin , Yu Da‐hai , Yu Bing‐zhi 
Published: August 2006

AbstractIn order to study the relationship between mTOR (mammalian target of rapamycin) and tumorigenesis, we investigated the expression and activity of mTOR, and its substrates, α1, α2, β1 and β2 isoforms of p70S6 kinase (p70S6K) and eukaryotic initiation factor 4E binding protein‐1 (4EBP‐1) in oral squamous carcinoma and Hela cells using RT‐PCR, immunohistochemistry, statistical analysis and Western blotting. The result of Western blots showed that in poorly differentiated oral squamous carcinoma, the expression level of mTOR and p70S6k increased in M phase, while that of 4EBP‐1 decreased. The results of RT‐PCR and immunohisteochemistry assay are the same as that of Western blot. In Hela cells, the RT‐PCR results showed that the level of mTOR mRNA did not change during the cell cycle. In M phase, the expression of α1, α2, β1 and β2 isoforms of p70S6K increased noticeably, while the expression of 4EBP‐1 decreased. The immunoblot results in Hela cells were consistent with the RT‐PCR results. Furthermore, the activity assays in Hela cells suggested that,in phase G2 and M, the activity of mTOR was maintained at a higher level than in any other phase, while 4EBP‐1 decreased in phase M. These results may help in further investigations of the important role of mTOR in cell cycle and tumorigenesis. Copyright © 2006 John Wiley & Sons, Ltd.
On the differential lipolytic capabilities of rat spleen and cardiac muscle. An in vitro incubation in conjunction with chromatographic and densitometric analysis
Authors: Helmy Fatma M 
Published: August 2006

AbstractThe phospholipid profiles of newborn, young adult and aged rat heart and spleen and their in vitro response to endogenous phospholipases at pH 7.4 and 38°C for 60 min were analysed by thin layer chromatography (TLC) technology and densitometry measurement. The noticeable high level of cardiolipin (CL) and its preferential deacylation, as detected by the formation of monolysocardiolipin (MLCL) and concurrent reduction of CL level were the most prevalent lipolytic events of rat cardiac muscle (newborn, young adult and aged) but the least prevalent in rat spleen. The level of ethanolamine plasmalogen (PE) was high in both the rat spleen and cardiac muscle (newborn, young adult and aged). Following in vitro incubation, the reduction in the level of PE and the high level of lyso alkenyl PE produced were most conspicuous in rat spleen (newborn, young adult and aged) and noticeably less in rat cardiac muscle. These data clearly illustrate the differential response of the endogenous substrates (phospholipids) to the endogenous phospholipases of these two tissues, and probably are related to their physiological activities in vivo. Copyright © 2006 John Wiley & Sons, Ltd.
The apoptosis modulator and tumour suppressor protein RBM5 is a phosphoprotein
Authors: Shu Yanjun , Rintala‐Maki Nina D. , Wall Vanessa E. , Wang Ke , Goard Carolyn A. , Langdon Colleen E. , Sutherland Leslie C. 
Published: August 2006

AbstractRBM5/LUCA‐15/H37 is a nuclear SR‐related RNA binding protein with the ability to modulate both apoptosis and the cell cycle, and retard tumour formation. How RBM5 functions to carry out these, potentially interrelated, biological activities is unknown. Since reversible phosphorylation has been shown to play an important role in the regulation of SR protein function, apoptosis and cell cycle control, in an attempt to elucidate the underlying mechanisms regulating RBM5 function, the phosphorylation status of RBM5 was investigated. Whole cell lysate from growing cell cultures was treated with the broad phosphatase spectrum of CIP, resulting in a decrease in the molecular mass of RBM5. A similar decrease in molecular mass, of a subset of RBM5 proteins, was observed during growth factor deprivation, in a manner consistent with partial dephosphorylation of RBM5. Molecular mass increased upon growth factor addition, demonstrating that this apoptosis‐associated alteration in molecular mass was a reversible process. Immunoprecipitation and mutagenesis experiments strongly suggested that phosphotyrosines are not present in RBM5 under normal growth conditions, and that serine 69 is phosphorylated, but not by Akt kinase. Taken together, these results suggest that reversible phosphorylation of RBM5 is a mechanism capable of regulating RBM5 participation in modulating apoptosis, and perhaps tumour suppression. Copyright © 2006 John Wiley & Sons, Ltd.
Blocking BE301622 gene expression by RNAi initiates differentiation of neural stem cells in rat
Authors: Wen Tieqiao , Bao Kuiyi , Li Hailong 
Published: August 2006

AbstractNeural stem cells (NSCs) are capable of differentiating into neurons, astrocytes and oligodendrocytes. However, the molecular mechanisms regulating NSCs differentiation are not well understood. Our previous research by microarray analysis certified that a lot of genes are differentially expressed in the course of NSC differentiation. In this study we report the function of one of these genes, BE301622, by RNAi techniques. To silence the BE301622 gene, a long, double‐stranded RNA (dsRNA) was synthesized by using a kit (Ambion T7 MegaScript) and transformed into NSCs. Expression of mRNA was tested through RT‐PCR. The result showed the expression of BE301622 gene was specificially suppressed. This finding effectively validated that BE301622 is involved in the differentiation of NSCs. Copyright © 2006 John Wiley & Sons, Ltd.
Hexylene‐ and Octylene‐Bridged Polysilsesquioxane Hybrid Crystals Self‐Assembled by Dimeric Building Blocks with Ring Structures
Authors: Zhou Xufeng , Yang Sui , Yu Chengzhong , Li Zhenhua , Yan Xiaoxia , Cao Yong , Zhao Dongyuan 
Published: August 2006

AbstractWe report the synthesis of novel polysilsesquioxane hybrid crystals prepared from two precursors with hexylene‐ and octylene‐bridged groups. Both crystals are composed of bimolecular rings (18‐ and 22‐membered, respectively) formed by one‐step condensation of two hydrolyzed monomers. The hydrogen bonds between silanol groups and the weak van der Waal's interactions between alkyl chains link the large rings as building blocks together into self‐assembled, three‐dimensional molecular crystalline structures. The precise control of the sol–gel process is considered to be the crucial factor in fabricating flexible long alkyl chains into an ordered stacking. These contributions extend the understanding of the sol–gel chemistry of polysilsesquioxanes.
1,3,5‐Triazepan‐2,6‐diones as Structurally Diverse and Conformationally Constrained Dipeptide Mimetics: Identification of Malaria Liver Stage Inhibitors from a Small Pilot Library
Authors: Lena Gersande , Lallemand Eliette , Gruner Anne Charlotte , Boeglin Joel , Roussel Solveig , Schaffner Arnaud‐Pierre , Aubry André , Franetich Jean‐François , Mazier Dominique , Landau Irène , Briand Jean‐Paul , Didierjean Claude , Rénia Laurent , Guichard Gilles 
Published: August 2006

AbstractThe development of the 1,3,5‐triazepan‐2,6‐dione system as a novel, conformationally restricted, and readily accessible class of dipeptidomimetics is reported. The synthesis of the densely functionalized 1,3,5‐triazepan‐2,6‐dione skeleton was achieved in only four steps from a variety of simple linear dipeptide precursors. To extend the practical value of 1,3,5‐triazepane‐2,6‐diones, a general polymer‐assisted solution‐phase synthesis approach amenable to library production in a multiparallel format was developed. The conformational preferences of the 1,3,5‐triazepan‐2,6‐dione skeleton were investigated in detail by NMR spectroscopy and X‐ray diffraction. The ring exhibits a characteristic folded conformation which was compared to that of related dipeptide‐derived scaffolds including the more planar 2,5‐diketopiperazine (DKP). Molecular and structural diversity was increased further through post‐cyclization appending operations at urea nitrogens. Preliminary biological screens of a small collection of 1,3,5‐triazepan‐2,6‐diones revealed inhibitors of the underexplored malaria liver stage and suggest strong potential for this dipeptide‐derived scaffold to interfere with and to modulate biological pathways.
Extended Applications of Di‐tert‐butylsilylene‐Directed α‐Predominant Galactosylation Compatible with C2‐Participating Groups toward the Assembly of Various Glycosides
Authors: Imamura Akihiro , Kimura Akiyoshi , Ando Hiromune , Ishida Hideharu , Kiso Makoto 
Published: August 2006

AbstractThe high versatility of di‐tert‐butylsilylene(DTBS)‐directed α‐predominant galactosylation have been extended to the construction of difficult glycan sequences. First, to investigate the compatibility of the α‐predominant reaction with various glycosylation systems a variety of 4,6‐O‐DTBS‐tethered galactosaminyl or galactosyl donors were synthesized efficiently, which have C2‐participating groups with a wide variety of leaving groups such as alkylsulfenyl, halide, trichloroacetimidate groups. The results of the detailed examination of the glycosylation reaction using the glycosyl donors showed the wide scope of the 4,6‐DTBS‐directed α‐galactosylation. In the next step, the stereoselective construction of α‐GalN‐Ser/Thr sequences was examined by employing the DTBS‐directed glycosylation. As a result, various types of serine and threonine derivatives were glycosylated α‐selectively, producing α‐GalN‐Ser/Thr sequences in high yields. Moreover, the DTBS‐directed galactosylation was successfully applied for the synthesis of α‐tetrasaccharyl‐Ser segment of glycophorin A.
One‐Step Hetarylation of Steroids: Regioselective Synthesis of New Estrone Derivatives.
Authors: Chupakhin Oleg N. , Beresnev Dmitry G. , Itsikson Nadezhda A. 
Published: August 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Stereospecific Ester Activation in Nitrite‐Mediated Carbohydrate Epimerization.
Authors: Dong Hai , Pei Zhichao , Ramstroem Olof 
Published: August 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
An Approach to the Total Synthesis of the Cylindricine B (I) Pyridoquinoline Subclass of Tricyclic Marine Ascidian Alkaloids.
Authors: Chao Wenchun , Mahajan Yogesh R. , Weinreb Steven M. 
Published: August 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of Tricyclic Pyrano[2,3‐e]isoindolin‐3‐ones as the Core Structure of Stachybotrin A, B, and C.
Authors: Inoue Seiichi , Kim Riyoung , Hoshino Yujiro , Honda Kiyoshi 
Published: August 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis and Transformations of Ethyl 3‐Formyl‐1H‐indole‐2‐carboxylate. Preparation of Aplysinopsin and β‐Carboline Thiohydantoin Analogues.
Authors: Jakse Renata , Bevk David , Golobic Amalija , Svete Jurij , Stanovnik Branko 
Published: August 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.