bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal Coordination Architectures of 2,3‐Bis(triazol‐1‐ylmethyl)quinoxaline: Effect of Metal Ion and Counterion on Complex Structures
Authors: Du Jian‐Long , Hu Tong‐Liang , Li Jian‐Rong , Zhang Shu‐Ming , Bu Xian‐He
Published: January 2008

A series of complexes, [ZnLCl2]2 (1), [ZnL2(NO3)2]∞ (2), [MnL2(NO3)2]∞ (3), {[ZnL2(H2O)2](ClO4)2(CH3COCH3)2}∞ (4), {[MnL2(H2O)2](ClO4)2(CH3COCH3)2}∞ (5), {[CdL2(H2O)2]‐(ClO4)2(H2O)6}∞ (6), and {[AgL](ClO4)(H2O)1.5}∞ (7), based on the flexible ligand 2,3‐bis(triazol‐1‐ylmethyl)quinoxaline (L) were synthesized and characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, and single‐crystal X‐ray diffraction. Complex 1 is a dinuclear macrocyclic molecular, which is further linked into a 1D supramolecular chain by intermolecular C–H···Cl weak interactions. The metal centers in 2 and 3 coordinate two NO3– anions, and the flexible ligand bridges M(NO3)2 [M = ZnII or MnII] units to form 1D chain structures. Complexes 4, 5, and 6 show a 2D network structure with (4,4) topology. As expected, complex 7 has a 1D strand chain structure that is different than other MII complexes (4, 5, and 6) with the same ligand. These chains are further extended into a 2D supramolecular network by O···Ag···O weak interactions. In all these complexes, the ligand bridges in a similar mode; however, the complexes have different structures ranging from a dinuclear structure to a 2D network mainly due to the differences in the coordination geometries of the metal centers and counterions. These results reveal that the coordination geometry of metal ions and the coordinating abilities of the counterions play important roles in defining the overall structure of metal–organic frameworks. In addition, the fluorescent properties of complexes 1, 2, 4, 6, 7, and ligand L and the EPR spectra of complex 5 were also investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Brave New World: The Heteroatom Chemistry of 1,3,2,4‐Benzodithiadiazines and Related Compounds
Authors: Blockhuys Frank , Gritsan Nina P. , Makarov Alexander Yu. , Tersago Karla , Zibarev Andrey V.
Published: January 2008

This review highlights the most important advances in the heteroatom chemistry of 1,3,2,4‐benzodithiadiazines (π‐excessive and formally antiaromatic heterocycles), covering methods for synthesis, nontrivial features of the molecular and π‐electronic structure, spectral properties, and reactivity, in particular the transformations into persistent π‐radicals. The chemistry of 1,3,2,4‐benzodithiadiazines is compared to that of related chalcogen–nitrogen compounds, both cyclic and acyclic.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Small Molecule‐Controlled Spontaneous Growth of Rose‐Like Se Crystals at Room Temperature
Authors: Deng Da‐Wei , Yu Jun‐Sheng , Pan Yi
Published: January 2008

The spontaneous growth of rose‐like Se crystals in aqueous solutions at room temperature is reported. The formation of rose‐like Se crystals is based on the oxidation of Na2Se in the presence of thioglycerol solution at pH = 11 in a dark ambient atmosphere. In alkaline solutions, the growth evolution of rose‐like Se crystals with aging time was followed by scanning electron microscopy (SEM), and an interesting formation process from initial Se monomers to amorphous Se (a‐Se) spheres, and to the final rose‐like complex structures of Se crystals was observed. Seven kinds of small molecules with different structures, including 1‐thioglycerol (TG), mercaptamine (MA), L‐cysteine (L‐cys), 3‐mercaptopropionic acid (MPA), thioglycolic acid (TGA), glycerol (GLY), and L‐serine (L‐ser), were used to manipulate the growth of Se crystals. The experimental results show that the structures of the small molecules play a key role in the growth of the Se crystals. The presence of thiols in the structure of the small molecules is favorable for the formation of the aggregates of Se crystals, and other termini, such as –NH2, –OH, or –COO–, will determine whether the aggregates of Se crystals are made up of Se slices or Se prisms. These observations suggest that the ligand molecules have a crucial effect on the nucleation, monomers, and growth of nanocrystals. The selection of ligands can be extended to other important materials for further preparation of nanocrystals with desired shapes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Syntheses, Crystal Structures, and Magnetic Properties of Copper(II) and Manganese(II) Compounds Constructed from 5‐Sulfoisophthalic Acid (H3SIP) and 2,2′‐Bipyridine (bpy) Ligands
Authors: Liu Qing‐Yan , Wang Yu‐Ling , Zhao Jun , Xu Li
Published: January 2008

The compounds [Cu2(SIP‐O)(bpy)2(H2O)2]·7H2O (1) and [Mn(HSIP)(bpy)]n (2) were synthesized by the hydrothermal reactions of Cu(OH)2 or MnCl2, 5‐sulfoisophthalic acid monosodium salt (NaH2SIP), and 2,2′‐bipyridine (bpy). Single‐crystal X‐ray diffraction reveals that the unprecedented hydroxylation of SIP3– catalyzed by Cu2+ occurs and produces the discrete SIP‐O4–‐bridged dicopper(II) compound 1. The hydrogen‐bonding association of the seven lattice water molecules of 1 leads to the formation of an unusual 2D‐layered water consisting of fused four‐ and sixteen‐membered water rings and a discrete water octamer consisting of a cyclic tetramer and four dangling water molecules. Compound 2 is a 3D coordination polymer and has two kinds of topologically equivalent 4‐connected nodes based on Mn2+ and HSIP2– with a rare (4.65) topology.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and Characterization of Atrop­isomers Arising from 1,3‐Cyclohexanediones by Intermolecular Tandem‐Michael/Michael Additions
Authors: Luna Liliana E. , Seoane Gustavo , Cravero Raquel M.
Published: January 2008

Intermolecular tandem‐Michael/Michael addition reactions of alkyne acceptors and CH‐acidic compounds such as 1,3‐cyclohexanedione (2a) and dimedone (2b) under L‐proline catalysis furnished four new products 1a–d with C2 axial chirality. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Benzoxepine Esters as Precursors of the Wound‐Activated Chemical Defence of Mycena galopus
Authors: Peters Silke , Jaeger Robert J. R. , Spiteller Peter
Published: January 2008

The native precursors E/Z‐1a to E/Z‐1e and 2a–2e of the antifungally active benzoxepines E/Z‐1 and 2 have been isolated from intact fruiting bodies of Mycena galopus. These precursors turned out to be fatty acid esters of the benzoxepines (pterulones) E/Z‐1 and 2. Metabolic profiling of ethyl acetate extracts from intact fruiting bodies, from the latex and from mechanically wounded fruiting bodies revealed that the known antifungally active benzoxepines E/Z‐1 and the previously unknown benzoxepines 2 are only present in injured fruiting bodies. Intact fruiting bodies and the latex, however, exclusively contain the corresponding ester derivatives E/Z‐1a to E/Z‐1e and 2a–2e. Unlike the antifungally active benzoxepines E/Z‐1 and 2, the esters E/Z‐1a to E/Z‐1e present in intact fruiting bodies turned out to be inactive. Upon injury the inactive esters E/Z‐1a to E/Z‐1e are cleaved by a putative esterase, and the bioactive benzoxepines E/Z‐1 and 2 are released, suggesting a wound‐activated defence mechanism of M. galopus against yeasts and parasitic fungi. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Model for Light‐Triggered Porphyrin Anticancer Prodrugs Based on an o‐Nitrobenzyl Photolabile Group
Authors: Lin Weiying , Peng Daiwei , Wang Bin , Long Lingliang , Guo Cancheng , Yuan Jinbin
Published: January 2008

A model for light‐triggered porphyrin anticancer prodrug 1 was designed and synthesized. Upon photolysis, prodrug 1 can efficiently liberate the anticancer drug tegafur. The MTT assay demonstrates that prodrug 1 is significantly less toxic than its parent drug tegafur, and 1 can release tegafur upon photoactivation in vitro. The light‐triggered porphyrin anticancer prodrug technique developed herein may find useful applications in chemotherapy to minimize the side effects of anticancer drugs because of the tumor affinity property of porphyrin and the light‐controllable anticancer drug dosing. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Modulation of gene methylation by genistein or lycopene in breast cancer cells
Authors: King‐Batoon Audrey , Leszczynska Joanna M. , Klein Catherine B.
Published: January 2008

Dietary agents with chemopreventive potential, including soy‐derived genistein and tomato‐derived lycopene, have been shown to alter gene expression in ways that can either promote or potentially inhibit the carcinogenic processes. To begin to explore the mechanisms by which these agents may be acting we have examined the DNA methylation modulating capacity of genistein or lycopene for several genes relevant to breast cancer in the breast cancer cell lines MCF‐7 and MDA‐MB‐468, as well as in immortalized but noncancer fibrocystic MCF10A breast cells. We find using methylation specific PCR (MSP) that a low, nontoxic concentration of genistein (3.125 μM, resupplemented every 48 hr for 1 week) or a single dose of lycopene (2 μM) partially demethylates the promoter of the GSTP1 tumor suppressor gene in MDA‐MB‐468 cells. RT‐PCR studies confirm a lack of GSTP1 expression in untreated MDA‐MB‐468, with restoration of GSTP1 expression after genistein or lycopene treatment. The RARβ2 gene however, was not demethylated by genistein or lycopene in either of these breast cancer cell lines. But, lycopene (2 μM, once per week for 2 weeks) did induce demethylation of RARβ2 and the HIN‐1 genes in the noncancer MCF10A fibrocystic breast cells. These data show for the first time that the tomato carotenoid lycopene has direct DNA demethylating activity. In summary, both genistein and lycopene, at very low, dietarily relevant concentrations can potentially mitigate tumorigenic processes via promoter methylation modulation of gene expression. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
A finite volume‐based high‐order, Cartesian cut‐cell method for wave propagation
Authors: Popescu Mihaela , Vedder Rick , Shyy Wei
Published: January 2008

Computational aeroacoustics requires numerical techniques capable of yielding low artificial dispersion and dissipation to preserve the amplitude and the frequency characteristics of the physical processes. Furthermore, for engineering applications, the techniques need to handle irregular geometries associated with realistic configurations. We address these issues by developing an optimized prefactored compact finite volume (OPC‐fv) scheme along with a Cartesian cut‐cell technique. The OPC‐fv scheme seeks to minimize numerical dispersion and dissipation while satisfying the conservation laws. The cut‐cell approach treats irregularly shaped boundaries using divide‐and‐merge procedures for the Cartesian cells while maintaining a desirable level of accuracy. We assess these techniques using several canonical test problems, involving different levels of physical and geometric complexities. Richardson extrapolation is an effective tool for evaluating solutions of no high gradients or discontinuities, and is used to evaluate the performance of the solution technique. It is demonstrated that while the cut‐cell method has a modest effect on the order of accuracy, it is a robust method. The combined OPC‐fv scheme and the Cartesian cut‐cell technique offer good accuracy as well as geometric flexibility. Copyright © 2008 John Wiley & Sons, Ltd.
A second‐order semi‐implicit hybrid scheme for one‐dimensional Boussinesq‐type waves in rectangular channels
Authors: Soares‐Frazão Sandra , Guinot Vincent
Published: January 2008

A numerical procedure is proposed for the solution of the Boussinesq equations in rectangular channels over a horizontal bed. The Boussinesq equations account for non‐hydrostatic effects in free‐surface flows. The proposed approach is a predictor–corrector procedure where the hyperbolic part of the equations is treated using a higher‐order estimate of the variable slope of the Godunov‐type, MUSCL scheme. The proposed slope estimate is third‐order accurate on irregular grids and fourth‐order accurate on regular grids. The dispersive, non‐hydrostatic terms are treated using a semi‐implicit discretization. A stability analysis of the proposed predictor–corrector procedure shows that optimal accuracy is achieved when the implicitation parameter is set equal to 0.5. This analysis is confirmed by numerical experiments, whereby the propagation of a solitary wave and the development of an undular bore are reproduced and compared successfully with the available analytical solutions. The proposed method is shown to be of a good level of accuracy without being too sensitive to the numerical parameters. Its applicability in practical problems is illustrated by a comparison with laboratory experiments. Copyright © 2008 John Wiley & Sons, Ltd.
Modified propagators of parareal in time algorithm and application to Princeton Ocean model
Authors: Liu Yueming , Hu Jianwei
Published: January 2008

In this paper, two modified propagators of parareal in time algorithm are presented and applied to the Princeton Ocean model (POM). The parareal algorithm was pioneered by Lions et al. (C. R. Acad. Sci. Paris Sér. I Math. 2001; 332:661–668) and later improved in a paper by Bal and Maday (Proceedings of the Workshop on Domain Decomposition, Zurich, Switzerland, Lecture Notes in Computer Science and Engineering Series, vol. 23. Springer: Berlin, 2002). Alternative formulations have also been presented, where the parallel in time algorithm proposed by Farhat and Chandesris (Int. J. Numer. Methods Eng. 2003; 58:1397–1434) is the most important one. This algorithm enables parallel computation using a decomposition of the interval of time integration. Solutions are obtained sequentially on the coarse time grid and on the fine time grid in parallel. A practical problem for the Bohai Sea is calculated on the supercomputer cluster Nankai Stars. The properties of the modified propagators are analyzed in this paper. Copyright © 2008 John Wiley & Sons, Ltd.
A stable pressure‐correction scheme for variable density flows involving non‐premixed combustion
Authors: Rauwoens P. , Vierendeels J. , Merci B.
Published: January 2008

An efficient time‐accurate algorithm is presented for numerical simulations of low‐Mach number variable density flows in the context of non‐premixed flames. The algorithm is based on a segregated solution formalism in the class of pressure‐correction methods. It shows good conservation properties and returns stable results, regardless of the difference in density between neighboring cells. A simplified Burke–Schumann flame model is used to describe the heat release due to mixing of fuel and oxidizer. The convergence rate of the method is discussed for a 1D channel flow, containing fuel and oxidizer. Copyright © 2008 John Wiley & Sons, Ltd.
Ovca1, a candidate gene of the genetic modifier of Tp53, Mop2, affects mouse embryonic lethality
Authors: Liang Min , Ayanga Bernard , Du Shuhua , Godwin Andrew K. , Hartsock Jennifer K. , Evans Susan C.
Published: January 2008

In this study, we show genetic modifier genes of Tp53 that can exacerbate embryonic abnormalities. Using a mouse model in which CE/J mice were crossed with the Tp53‐null 129/Sv (129‐Trp53tm1 Tyj) mice, a subset of Tp53+/− and −/− male and female embryos died during gestation. Our hypothesis, based on the genotypes of survivors, is that two genetic modifiers and a Tp53 null allele lead to an increase in embryonic lethality. We previously identified a recessive modifier (Mop1) from CE/J mice on chromosome 11 centromeric to Tp53. We have uncovered a dominant modifier (Mop2) from 129/Sv mice telomeric to Tp53. We discovered a polymorphic change (321P→321S) of Ovca1 within the Mop2 locus of CE/J mice. This polymorphism increased both mRNA and protein levels of OVCA1 in various tissues. CE/J primary cells cultured from different tissues proliferated more rapidly than 129/Sv cells. In addition, CE/J cells cycled while 129/Sv cells had a higher arrest in the G1 phase. Transfection of Ovca1 containing the 321P polymorphism into CE/J cells caused a higher G1 arrest. The pattern of OVCA1 expression also changed from being diffuse throughout the cytoplasm in 129/Sv cells to being punctuate in the cytoplasm of CE/J cells. Tp53+/− abnormal embryos had more proliferating cells than normal embryos, but no obvious difference in differentiated neuronal cells. Tp53−/− small embryos had less differentiated neuronal cells and proliferating cells than normal embryos. Thus, a polymorphism of Ovca1, combined with Mop1, genetically modifies embryonic lethality in Tp53 deficient mice. © 2008 Wiley‐Liss, Inc.
Toddlers' use of cues in a search task
Authors: Keen Rachel , Berthier Neil , Sylvia Monica R. , Butler Samantha , Prunty Patricia K. , Baker Rachel K.
Published: January 2008

Search for a ball that has undergone hidden motion rapidly improves during the second year of life (Dev. Psychol., 2000; 36:394–401). In three experiments we investigated whether the poor performance of younger toddlers was due to attentional failure by highlighting the major cue for the hidden object. We observed only slight improvement in search behaviour. We performed two other experiments that tested the depth of understanding of 3‐year‐olds in this task and found that their performance was robust to changes in the apparatus and experimental procedures. Overall, the results point to a rapidly developing ability in the second year of life to either reason about space or select the correct motor response in search tasks. Copyright © 2008 John Wiley & Sons, Ltd.
Simple mathematical model for optimisation of rainwater storage reservoirs in the Cholistan desert
Authors: Kahlown Muhammad Akram , Majeed Abdul
Published: January 2008

The cost of constructing storage reservoirs in Cholistan was studied using a mathematical model. The variables studied were reservoir side slope and depth, seepage, evaporation and capacity of the reservoir. After computing the reservoir dimensions to store the required 15 140 m3, a full reservoir was assumed starting from 1 August of the year. The depth and quantity of water stored were then depleted by use, evaporation and seepage by the month. In this manner, the length of time that water would be available was computed. The study showed that under general conditions a 3 m deep reservoir would be depleted by December or January, a 4.6 m deep reservoir would be depleted by March or April and a 6 m deep reservoir would be depleted by April or May. Only a 7.6 or 9 m deep reservoir would contain water for a whole year provided that both seepage and evaporation are controlled. The recommended reservoir dimensions are 6 m deep with 1 : 2 or 1 : 3 side slopes, as these give minimum cost plus better water availability. The cost with the recommended optimal dimension was US$6 per m3 with good seepage and evaporation control. Copyright © 2008 John Wiley & Sons, Ltd.
In vitro cytotoxicity, hemolysis assay, and biodegradation behavior of biodegradable poly(3‐hydroxybutyrate)–poly(ethylene glycol)–poly(3‐hydroxybutyrate) nanoparticles as potential drug carriers
Authors: Chen Cheng , Cheng Yin Chung , Yu Chung Him , Chan Shun Wan , Cheung Man Ken , Yu Peter H. F.
Published: January 2008

Nanoparticles based on amorphous poly(3‐hydroxybutyrate)–poly(ethylene glycol)–poly(3‐hydroxybutyrate) (PHB‐PEG‐PHB) are potential drug delivery vehicles, and so their cytotoxicity and hemolysis assay were investigated in vitro using two kinds of animal cells. The PHB‐PEG‐PHB nanoparticles showed excellent biocompatibility and had no cytotoxicity on animal cells, even when the concentrations of the PHB‐PEG‐PHB nanoparticle dispersions were increased to 120 μg/mL. Moreover, no hemolysis was detected with the PHB‐PEG‐PHB nanoparticles, suggesting that the PHB‐PEG‐PHB nanoparticles were obviously much hemocompatible for drug delivery applications. In the presence of intracellular enzyme esterase, the biocompatible PHB‐PEG‐PHB nanoparticles might be hydrolyzed, and their biodegradable behavior was monitored by the fluorescence spectrum and the pH meter. The initial biodegradation rate of the PHB‐PEG‐PHB nanoparticles was closely related to the enzymatic amount and the PHB block length. Compared with that obtained from the fluorescence determination, the initial biodegradation rate from pH measurement was faster. The biodegraded products mainly consisted of 3HB monomer and dimer, which were the metabolites present in the body. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 87A: 290–298, 2008
Heparin dopant increases the electrical stability, cell adhesion, and growth of conducting polypyrrole/poly(L,L‐lactide) composites
Authors: Meng Shiyun , Rouabhia Mahmoud , Shi Guixin , Zhang Ze
Published: January 2008

Polypyrrole (PPy) is a promising conductive polymer for tissue engineering and bioelectrical applications. However, its electrical conductivity deteriorates easily in aqueous conditions. Cell adhesion to PPy is also relatively poor. The goal of this study was to simultaneously improve the electrical stability of and cell adhesion to PPy by using heparin (HE) as dopant, for HE is both a polyanion and an important glycosaminoglycan in cell membranes and extracellular matrix. PPy particles doped with HE were synthesized through emulsion polymerization using Fenton's reagent as an oxidant. X‐ray photoelectron spectroscopy (XPS), infrared and scanning electron microscopy (SEM) were used to investigate the PPy particles. Conductive biodegradable membranes of 102 to 103 Ω/square were prepared from 5% (w) PPy with various amounts of HE and 95% (w) poly(L,L‐lactide) (PPy/PLLA). Azure A staining was employed to quantify the HE exposed on the surface of the PPy particles and PPy/PLLA membranes. The distribution of HE on membranes was demonstrated by DAPI staining. Results showed that HE was incorporated into the PPy particles as counterions and presented on particle surface. A unique “filament”‐like morphology of the PPy preparation was observed at high‐HE content. The electrical stability of the PPy/PLLA membranes was tested in saline at 37°C for 500 h. Human skin fibroblasts were used to test the cell adhesion capacity. The conductive membranes containing HE‐doped PPy particles recorded significantly increased electrical stability, cell adhesion, and growth. The electrically more stable and cell adhesive conductive biodegradable membrane may act as a platform for various biomedical applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Orthotopic bone formation by implantation of apatite‐coated poly(lactide‐co‐glycolide)/hydroxyapatite composite particulates and bone morphogenetic protein‐2
Authors: Kim Sang‐Soo , Gwak So‐Jung , Kim Byung‐Soo
Published: January 2008

Bone morphogenetic proteins (BMPs) are the most potent osteoinductive growth factors. However, a delivery system is essential to take advantage of the osteoinductive effect of BMPs. In the present study, we tested the suitability of apatite‐coated poly(D,L‐lactide‐co‐glycolide)/nanohydroxyapatite (PLGA/HA) particulates as carriers for the controlled release of BMP‐2. The release of BMP‐2 from apatite‐coated PLGA/HA particulates was sustained for at least 4 weeks in vitro. A delivery system of apatite‐coated PLGA/HA particulates suspended in fibrin gel further slowed the BMP‐2 release rate. In vivo implantation of either Fibrin gel + BMP‐2 or Fibrin gel + apatite‐coated PLGA/HA particulates showed enhanced new bone formation in critical‐sized calvarial defects of rats 8 weeks after implantation, compared to implantation of fibrin gel only. Importantly, new bone formation was much higher in the defects treated with BMP‐2 delivery using apatite‐coated PLGA/HA particulates in fibrin gel (Fibrin gel + PLGA/HA + BMP‐2 group) than in the defects treated either with apatite‐coated PLGA/HA particulates in fibrin gel (Fibrin gel + BMP‐2 group) or with BMP‐2 delivery using fibrin gel alone (Fibrin gel + BMP‐2 group). BMP‐2 and osteoinductive HA had an additive effect on orthotopic bone formation. In conclusion, the apatite‐coated PLGA/HA particulates showed good results as carriers for BMP‐2. The BMP‐2 delivery system showed high osteogenic capability in a rat calvarial bone defect model. The local and sustained delivery system for BMP‐2 developed in this study may be useful as a carrier for BMP‐2 and would enhance bone regeneration efficacy for the treatment of large bone defects. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Overcoming muscle atrophy in a hibernating mammal despite prolonged disuse in dormancy: Proteomic and molecular assessment
Authors: Lee Kisoo , Park Joo Young , Yoo Woojae , Gwag Taesik , Lee Ju‐Woon , Byun Myung‐Woo , Choi Inho
Published: January 2008

Prolonged disuse of skeletal muscle causes significant loss of myofibrillar contents, muscle tension, and locomotory capacity. However, hibernating mammals like bats appear to deviate from this trend. Although low functional demands during winter dormancy has been implicated as a factor contributing to reduced muscle loss, the precise mechanism that actively prevents muscle atrophy remains unclear. We explored proteomic and molecular assessments of bat muscle to test a hypothesis that expression levels of major myofibrillar proteins are retained during hibernation, with periodic arousals utilized as a potential mechanism to prevent disuse atrophy. We examined changes in myofibrillar contents and contractile properties of the pectoral or biceps brachii muscles of the batMurina leucogasterin summer active (SA), hibernation (HB) and early phase of arousal (AR) states. We found the bat muscles did not show any sign of atrophy or tension reduction over the 3‐month winter dormancy. Levels of most sarcomeric and metabolic proteins examined were maintained through hibernation, with some proteins (e.g., actin and voltage dependent anion channel 1) 1.6‐ to 1.8‐fold upregulated in HB and AR compared to SA. Moreover, expression levels of six heat shock proteins (HSPs) including glucose‐regulated protein 75 precursor were similar among groups, while the level of HSP70 was even 1.7‐fold higher in HB and AR than in SA. Thus, considering the nature of arousal with strenuous muscle shivering and heat stress, upregulation or at least balanced regulation of the chaperones (HSPs) would contribute to retaining muscle properties during prolonged disuse of the bat. J. Cell. Biochem. 104: 642–656, 2008. © 2008 Wiley‐Liss, Inc.
Regucalcin increases Ca2+‐ATPase activity in the mitochondria of brain tissues of normal and transgenic rats
Authors: Yamaguchi Masayoshi , Takakura Yusei , Nakagawa Taeko
Published: January 2008

The role of regucalcin, which is a regulatory protein in intracellular signaling, in the regulation of Ca2+‐ATPase activity in the mitochondria of brain tissues was investigated. The addition of regucalcin (10−10 to 10−8 M), which is a physiologic concentration in rat brain tissues, into the enzyme reaction mixture containing 25 µM calcium chloride caused a significant increase in Ca2+‐ATPase activity, while it did not significantly change in Mg2+‐ATPase activity. The effect of regucalcin (10−9 M) in increasing mitochondrial Ca2+‐ATPase activity was completely inhibited in the presence of ruthenium red (10−7 M) or lanthanum chloride (10−7 M), both of which are inhibitors of mitochondrial uniporter activity. Whether the effect of regucalcin is modulated in the presence of calmodulin or dibutyryl cyclic AMP (DcAMP) was examined. The effect of regucalcin (10−9 M) in increasing Ca2+‐ATPase activity was not significantly enhanced in the presence of calmodulin (2.5 µg/ml) which significantly increased the enzyme activity. DcAMP (10−6 to 10−4 M) did not have a significant effect on Ca2+‐ATPase activity. The effect of regucalcin (10−9 M) in increasing Ca2+‐ATPase activity was not seen in the presence of DcAMP (10−4 M). Regucalcin levels were significantly increased in the brain tissues or the mitochondria obtained from regucalcin transgenic (RC TG) rats. The mitochondrial Ca2+‐ATPase activity was significantly increased in RC TG rats as compared with that of wild‐type rats. This study demonstrates that regucalcin has a role in the regulation of Ca2+‐ATPase activity in the brain mitochondria of rats. J. Cell. Biochem. 104: 795–804, 2008. © 2008 Wiley‐Liss, Inc.
Ab initio determination of the flexibility of 2′‐aminoribonucleosides and 2′‐aminoarabinonucleosides inserted in duplexes
Authors: Barbe Sophie , Le Bret Marc
Published: January 2008

The sugar puckering of adenosine and uridine nucleosides with an amino group at 2′ in the ribo or arabino orientations are determined using high‐level quantum mechanical calculations Only the conformations that have dihedrals compatible with their insertion into a duplex are retained. The amino group has always been found to be pyramidal and its orientation governs the conformation of the sugar. The energetically most favorable conformation of the 2′‐aminoribonucleosides has the south puckering but must be discarded. For another orientation of the 2′‐amino group, the conformation is energetically less favorable but has the north puckering. Calculations performed in the presence of a water molecule give similar results but with a smaller energy gap. The model then explains why the insertion of a 2′‐aminoribonucleotide destabilizes double‐stranded RNAs and also double‐stranded DNAs. In the arabino orientation, an NH2 substituent at 2′ favors north puckering. In contrast to 2′‐aminoribonucleosides, deoxynucleosides inserted into a duplex remain in the most energetically favorable conformation compatible with the canonical values of the torsion angles. The whole relaxed potential map, in the amplitude/pseudorotation space, shows that for natural deoxyadenosine there is only one valley in the east running from south to north puckering. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
Soft energy function and generic evolutionary method for discriminating native from nonnative protein conformations
Authors: Chiu Yi‐yuan , Hwang Jenn‐kang , Yang Jinn‐moon
Published: January 2008

We have developed a soft energy function, termed GEMSCORE, for the protein structure prediction, which is one of emergent issues in the computational biology. The GEMSORE consists of the van der Waals, the hydrogen‐bonding potential and the solvent potential with 12 parameters which are optimized by using a generic evolutionary method. The GEMSCORE is able to successfully identify 86 native proteins among 96 target proteins on six decoy sets from more 70,000 near‐native structures. For these six benchmark datasets, the predictive performance of the GEMSCORE, based on native structure ranking andZ‐scores, was superior to eight other energy functions. Our method is based solely on a simple and linear function and thus is considerably faster than other methods that rely on the additional complex calculations. In addition, the GEMSCORE recognized 17 and 2 native structures as the first and the second rank, respectively, among 21 targets in CASP6 (Critical Assessment of Techniques for Protein Structure Prediction). These results suggest that the GEMSCORE is fast and performs well to discriminate between native and nonnative structures from thousands of protein structure candidates. We believe that GEMSCORE is robust and should be a useful energy function for the protein structure prediction. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
Latin squares with no small odd plexes
Authors: Egan Judith , Wanless Ian M.
Published: January 2008

Ak‐plex in a Latin square of ordernis a selection ofknentries in which each row, column, and symbol is represented preciselyktimes. A transversal of a Latin square corresponds to the casek = 1. We show that for all evenn > 2 there exists a Latin square of ordernwhich has nok‐plex for any odd$k < \lfloor {n\over 4} \rfloor$but does have ak‐plex for every other$k \le {1\over 2} n$. © 2008 Wiley Periodicals, Inc. J Combin Designs 16: 477–492, 2008
Suppression of human tumor cell proliferation by Smurf2‐induced senescence
Authors: Zhang Hong , Teng Yuchin , Kong Yahui , Kowalski Paul E. , Cohen Stanley N.
Published: January 2008

The limitation of proliferative potential in human somatic cells imposed by replicative senescence has been proposed as a mechanism of tumor suppression. The E3 ubiquitin ligase Smurf2 is up‐regulated during replicative senescence in response to telomere shortening, and induces senescence when expressed adventitiously in early passage or telomerase‐immortalized human fibroblasts. To investigate the generality of Smurf2's control of cell proliferation, we have studied the effects of Smurf2 up‐regulation on cell proliferation in early passage human mammary epithelial cells which normally do not show elevated expression of Smurf2 during senescence, and in 16 human cancer cell lines derived from both sarcomas and carcinomas. Here we report that Smurf2 up‐regulation induced senescence in a wide variety of human cell types, including highly neoplastic cell lines. Consistent with our previous findings, the ability of Smurf2 to arrest cell proliferation did not require its ubiquitin ligase activity. Furthermore, expression of the cyclin‐dependent kinase inhibitor p21 was increased in tumor cells undergoing Smurf2‐induced senescence, and such increase occurred independently of the transactivation function of p53. Our results, which reveal a previously unsuspected tumor suppression function for Smurf2‐induced senescence, suggest that modulation of Smurf2 action may be a useful strategy for inhibition of cancer cell growth. J. Cell. Physiol. 215: 613–620, 2008. © 2008 Wiley‐Liss, Inc.
Cytochrome P450 (CYP) 2J2 gene transfection attenuates MMP‐9 via inhibition of NF‐κβ in hyperhomocysteinemia
Authors: Moshal Karni S. , Zeldin Darryl C. , Sithu Srinivas D. , Sen Utpal , Tyagi Neetu , Kumar Munish , Hughes William M. , Metreveli Naira , Rosenberger Dorothea S.E. , Singh Mahavir , Vacek Thomas P. , Rodriguez Walter E. , Ayotunde Adeagbo , Tyagi Suresh C.
Published: January 2008

Hyperhomocysteinemia (HHcy) is associated with atherosclerotic events involving the modulation of arachidonic acid (AA) metabolism and the activation of matrix metalloproteinase‐9 (MMP‐9). Cytochrome P450 (CYP) epoxygenase‐2J2 (CYP2J2) is abundant in the heart endothelium, and its AA metabolites epoxyeicosatrienoic acids (EETs) mitigates inflammation through NF‐κβ. However, the underlying molecular mechanisms for MMP‐9 regulation by CYP2J2 in HHcy remain obscure. We sought to determine the molecular mechanisms by which P450 epoxygenase gene transfection or EETs supplementation attenuate homocysteine (Hcy)‐induced MMP‐9 activation. CYP2J2 was over‐expressed in mouse aortic endothelial cells (MAECs) by transfection with the pcDNA3.1/CYP2J2 vector. The effects of P450 epoxygenase transfection or exogenous supplementation of EETs on NF‐κβ‐mediated MMP‐9 regulation were evaluated using Western blot, in‐gel gelatin zymography, electromobility shift assay, immunocytochemistry. The result suggested that Hcy downregulated CYP2J2 protein expression and dephosphorylated PI3K‐dependent AKT signal. Hcy induced the nuclear translocation of NF‐κβ via downregulation of IKβα (endogenous cytoplasmic inhibitor of NF‐κβ). Hcy induced MMP‐9 activation by increasing NF‐κβ–DNA binding. Moreover, P450 epoxygenase transfection or exogenous addition of 8,9‐EET phosphorylated the AKT and attenuated Hcy‐induced MMP‐9 activation. This occurred, in part, by the inhibition of NF‐κβ nuclear translocation, NF‐κβ–DNA binding and activation of IKβα. The study unequivocally suggested the pivotal role of EETs in the modulation of Hcy/MMP‐9 signal. J. Cell. Physiol. 215: 771–781, 2008. © 2008 Wiley‐Liss, Inc.
Adenosine A1 and A2A receptor regulation of protein phosphatase 2A in the murine heart
Authors: Tikh Eugene I. , Fenton Richard A. , Chen Jiang‐Fan , Schwarzschild Michael A. , Dobson James G.
Published: January 2008

Adenosine plays a role in regulating the contractile function of the heart. This includes a positive ionotropic action via the adenosine A2A receptor (A2AR) and an inhibition of β1‐adrenergic receptor‐induced ionotropy (antiadrenergic action) via the adenosine A1 receptor (A1R). Phosphatase activity has also been shown to influence contractile function by affecting the level of protein phosphorylation. Protein phosphatase 2A (PP2A) plays a significant role in mediating the A1R antiadrenergic effect. The purpose of this study was to investigate the effects of A2AR and A1R on the activities of PP2A in hearts obtained from wild‐type (WT) and A2AR knockout (A2AR‐KO) mice. PP2A activities were examined in myocardial particulate and cytoplasmic extract fractions. Treatment of wild‐type hearts with the A1R agonist CCPA increased the total PP2A activity and increased the particulate:cytoplasmic PP2A activity ratio. Treatment with the A2AR agonist CGS‐21680 (CGS) decreased the total PP2A activity and decreased the particulate:cytoplasmic PP2A activity ratio. This indicated a movement of PP2A activity between cell fractions. The effect of CCPA was inhibited by CGS. In A2AR‐KO hearts the response to A1R activation was markedly enhanced whereas the response to A2AR activation was absent. These data show that A2AR and A1R regulate PP2A activity, thus suggesting an important mechanism for modulating myocardial contractility. J. Cell. Physiol. 216: 83–90, 2008. © 2008 Wiley‐Liss, Inc.
Purification of α‐toxin from Clostridium perfringens type A in PEG‐phosphate aqueous two‐phase systems: a factorial study
Authors: Cavalcanti Maria TH , Porto Tatiana S , Neto Benicio B , Lima‐Filho José L , Porto Ana L F , Pessoa Adalberto
Published: January 2008

BACKGROUND: Purification of α‐toxin produced by Clostridium perfringens type A in aqueous two‐phase systems (ATPS) was studied with a full two‐level factorial design on two factors (concentrations of 8000 g mol−1 PEG and phosphate salt at pH 8.0), to estimate the influence of these factors on the purification results.

RESULTS: The partition coefficient (K), purification factor (PF) and activity yield (Y) were strongly influenced by the PEG and phosphate concentrations. Raising the levels of the two factors increased these responses. The highest purification factor (5.7) was obtained with PEG and phosphate concentrations of 17.5% and 15%, respectively.

CONCLUSION: These results support the proposal that polymer excluded volume and hydrophobic interactions are the factors that drive the α‐toxin in PEG/phosphate aqueous two‐phase systems. Copyright © 2008 Society of Chemical Industry
Colloid deposition experiments as a diagnostic tool for biomass attachment onto bioproduct adsorbent surfaces
Authors: Tari Canan , Vennapusa RamiReddy , Cabrera Rosa B , Fernández‐Lahore Marcelo
Published: January 2008

BACKGROUND: Detrimental processing conditions can be expected in any downstream operation where direct contacting between a crude feedstock and a reactive solid phase is supposed to occur. In this paper we have investigated the factors influencing intact yeast cells deposition onto anion and cation exchangers currently utilized for expanded‐bed adsorption of biotechnological products. The aim of this study was twofold: (a) to confirm previous findings relating biomass deposition with surface energetics according to the extended Derjaguin, Landau, Verwey and Overbeek theory (XDLVO) theory; and (b) to provide a simple experimental tool to evaluate biomass deposition onto process surfaces.

RESULTS:Biomass deposition experiments were performed on an automated workstation utilizing a packed‐bed format. Two commercial ion exchangers intended for the direct capture of bioproducts in the presence of suspended biological particles were employed. Intact yeast cells in the late exponential phase of growth were selected as model bio‐colloids. Cell deposition was systematically evaluated as a function of fluid‐phase conductivity and quantitatively expressed as a biomass deposition parameter (α).

CONCLUSION: α ≤0.15 was established as a criterion to reflect negligible biomass adhesion to the process support(s). Biomass deposition experiments further confirmed predictions made on the basis of free interfacial energy calculations as per the extended DLVO approach. Copyright © 2008 Society of Chemical Industry
Some remarks about factors of graphs
Authors: Correa José R. , Matamala Martín
Published: January 2008

A (g, f)‐factor of a graph is a subset F of E such that for all $v \in V$, $g(v)\le {\rm deg}_{F}(v)\le f(v)$. Lovasz gave a necessary and sufficient condition for the existence of a (g, f)‐factor. We extend, to the case of edge‐weighted graphs, a result of Kano and Saito who showed that if $g(v)< \lambda {\rm deg}_{E}(v) < f (v)$ for any $\lambda\in [0,1]$, then a (g, f)‐factor always exist. In addition, we use results of Anstee to provide new necessary and sufficient conditions for the existence of a (g, f)‐factor. © 2008 Wiley Periodicals, Inc. J Graph Theory 57: 265–274, 2008
Quality of life in the long‐term survivors after total gastrectomy for gastric carcinoma
Authors: Tyrväinen Tuula , Sand Juhani , Sintonen Harri , Nordback Isto
Published: January 2008

Background and Objectives

Several studies report the health‐related quality of life (HRQoL) after total gastrectomy in short term but long‐term results have been less published.

Methods

One hundred and seventy two patients underwent total gastrectomy between years 1987–1999 for gastric carcinoma. In 2005, 30% of them were still alive. The final study population consisted of 25 patients less than 80 years of age, for whom validated control population data were available. The SF‐36 and 15D questionnaires were used as QoL instruments. The median follow‐up time from surgery was 9.

Results

The study group did not differ significantly in any of the SF‐36 sub scores from the normal population controls. There was no significant difference in the total score in 15D but the patients did statistically significantly worse than the normal population controls in sleeping, elimination and distress. There was significant weight loss during the follow up, but this was not associated with any of HRQoL changes.

Conclusions

This study shows that patients who survived for long‐term after total gastrectomy for gastric carcinoma do generally as well as the normal population controls, but depending on the QoL instrument used, may have lower QoL in some sub dimensions. J. Surg. Oncol. 2008;97:121–124. © 2008 Wiley‐Liss, Inc.
Thermohydrodynamic analysis of infinitely wide cycloidal profiled pad thrust bearing with rough surface and a comparison to plane profiled pad
Authors: Sharma R. K. , Pandey R. K.
Published: January 2008

This work reports the thermal analysis of hydrodynamically lubricated cycloidal profiled pad thrust bearing (CPPTB) using an efficient numerical method based on Lobatto quadrature technique. The performance parameters with smooth and rough surfaces of cycloidal and plane profiled pads are presented for various operating inputs. Significant increase in magnitude of pressure and substantial reduction in coefficient of friction are observed in the presence of relatively large amplitude of roughness over the surface of stationary pads. Comparisons are made for performance parameters achieved with plane profiled pad thrust bearing (PPPTB) and CPPTB. The load carrying capacity of CPPTB is found significantly high than the PPPTB for the provided set of operating parameters. Copyright © 2008 John Wiley & Sons, Ltd.
In Situ Polymerization of Olefins with Nanoparticles by Metallocene‐Catalysis
Authors: Kaminsky Walter , Funck Andreas
Published: January 2008

Exceptionally strong materials could be synthesized by filled polyolefins with nanosized, regid particles or fibers. Metallocene catalysts are excellent tools in the production of tailored microstructures as well as tacticities of polypropylenes. They are soluble in hydrocarbons and therefore can cover perfectly the surface of nano particles. Here multi‐walled carbon nanotubes (MWCNT) (diameter 15–25 nm, length up to 50 µm) were used as fillers. Before polymerization, the fillers were separated by ultra sound and then treated with methylaluminoxane (MAO). MAO reacts partially with defects and functional groups of oxidized MWCNT. Catalytically active centers are formed after adding the zirconocenes or other transition metal complexes directly on the CNT surface. The thickness of the polymer layer can be controlled by the monomer pressure and polymerization time. We obtained coatings of 5 to 100 nm. By this method carbon nanotubes can be covered also with isotactic or syndiotactic polypropylene, but also with polyethylene with any molecular mass. The nanocomposites obtained were especially investigated in regard to their crystallization behavior, which depended significantly on the matrix used.
Macromolecular Non‐Releasing Additives for Commercial Polyolefins
Authors: Sacchi Maria Carmela , Cogliati Clelia , Losio Simona , Costa Giovanna , Stagnaro Paola , Menichetti Stefano , Viglianisi Caterina
Published: January 2008

Four comonomers bearing a highly efficient phenolic antioxidant unit and different distance between the antioxidant moiety and the double bond have been prepared and tested in co‐polymerization with ethylene by means of three selected metallocene based catalysts. The possibility to obtain a masterbach suitable for melt blending with commercial polyolefins has been evaluated by modifying: i) the structure of the functionalized comonomer, ii) the kind of catalyst, iii) the polymerization conditions. The pair rac‐[Me2Si‐(2‐Me‐4,5‐BenzInd)2]ZrCl2 catalyst and comonomer with the longest spacer (8 methylene units) allowed the highest comonomer incorporation, while with rac‐(EBTHI)ZrCl2 catalyst the highest polymerization activity was observed. TGA analysis has been carried out on some of the copolymers in order to investigate the influence of type and amount of the comonomer on their thermal stability and to test the efficiency of the antioxidant group both in nitrogen and oxygen atmosphere.
Ethylene/Norbornene Copolymerization with iPr(Cp)(Flu)ZrCl2 Catalyst: Effect of MAO Cocatalyst and 3rd Monomer
Authors: Yoon Keun‐byoung , Choi Yeon Seok , Noh Seok Kyun , Lee Dong‐ho
Published: January 2008

The copolymerization of ethylene and norbornene (N) was carried out with iPr(Cp)(Flu)ZrCl2 catalyst and modified methylaluminoxane (MMAO) cocatalyst. The catalytic activity was dependent on the structure of MMAO, i.e., MMAO‐4 exhibited higher catalyst activity than MMAO‐3A containing more i‐butyl groups. The glass transition temperature (Tg) and the composition of the produced copolymer were not affected by MMAO type. With styrene derivatives as 3rd monomer, Tg of copolymer increased while the catalytic activity decreased. With the addition of 3rd monomer, not only the content of 3rd monomer but also the content of N increased.
One‐pot Synthesis of Long Chain Branch PP (LCBPP) Using Ziegler‐Natta Catalyst and Branching Reagents
Authors: Langston Justin A. , Colby Ralph H. , Shimizu Fumihiko , Suzuki Toru , Aoki Masaru , Chung T. C. Mike
Published: January 2008

A new class of long chain branched isotactic polypropylene (LCBPP) polymers with high molecular weights and well‐controlled structures are prepared via a combination of rac‐Me2Si(2‐Me‐4‐Ph‐Ind)ZrCl2/MAO catalyst and a T‐reagent, such as p‐(3‐butenyl)styrene. The T‐reagent can simultaneously serve two functions (comonomer and chain transfer agent) during metallocene‐mediated propylene polymerization in the presence of a small amount of hydrogen. 1H NMR and SEC equipped with triple detectors revealed most of polymer chain containing LCB structure. LCBPPs displayed a systematic increase in zero‐shear viscosity and Arrhenius flow activation energy as branch density increased. LCBPPs with high branch point density displayed thermorheologically complex behavior, and strain hardening was observed in extensional flow.