bluuebunny/crossref_metadata_2025 huggingface dataset:
Combination of microwave‐assisted micellar extraction with liquid chromatography tandem mass spectrometry for the determination of fluoroquinolone antibiotics in coastal marine sediments and sewage sludges samples
Authors: Montesdeoca‐Esponda Sarah , Sosa‐Ferrera Zoraida , Santana‐Rodríguez José Juan
Published: March 2011

In this work, a method for the analysis of fluoroquinolone antibiotics using microwave‐assisted micellar extraction combined with liquid chromatography–mass spectrometry detection has been developed. Different surfactants were tested for use as extractants in the isolation of the analytes from solid samples, and several experimental designs were evaluated for the determination and optimization of the variables that affect recovery from the matrix. Under optimal conditions, we obtained recoveries greater than 73% with relative standard deviations below 8%. Compounds were detected by liquid chromatography–electrospray ionization tandem mass spectrometry with detection limits between 0.15 and 0.55 ng g−1 and quantification limits between 0.49 and 1.85 ng g−1. Finally, the optimized method was applied in the determination of antibiotics in real solid samples. Four fluoroquinolones (levofloxacin, norfloxacin, ciprofloxacin and enrofloxacin) were found in coastal marine sediments taken close to a marine outfall and in sewage sludge samples from a wastewater treatment plant. Concentrations ranged between 0.81 and 34.3 ng g−1 in the sediments and 3.43 and 206.1 ng g−1 in the sludge. Copyright © 2011 John Wiley & Sons, Ltd.
Unusual Transglycosylation Activity of Flavobacterium meningosepticum Endoglycosidases Enables Convergent Chemoenzymatic Synthesis of Core Fucosylated Complex N‐Glycopeptides
Authors: Huang Wei , Li Jie , Wang Lai‐Xi
Published: March 2011

Structurally well defined, homogeneous glycopeptides and glycoproteins are indispensable tools for functional glycomics studies. By screening of various endo‐β‐N‐acetylglucosaminidases through the use of appropriate synthetic donor and acceptor substrates, we have found that the Flavobacterium meningosepticum endo‐β‐N‐acetyl‐glucosaminidases (GH family 18), including Endo‐F2 and Endo‐F3, were able to glycosylate α‐1,6‐fucosylated GlcNAc derivative to provide natural, corefucosylated complex‐type N‐glycopeptides. The Endo‐F2 and Endo‐F3 were efficient for transferring both sialylated and asialylated glycans and were highly specific for an α‐1,6‐fucosylated GlcNAc‐peptide as acceptor for transglycosylation, showing only marginal activity with non‐fucosylated GlcNAc‐peptides. In contrast, we found that the commonly used endoglycosidases such as Endo‐A and Endo‐M, which belong to GH family 85, were unable to take α‐1,6‐fucosyl‐GlcNAc derivative as acceptors for transglycosylation. The novel activity of Endo‐F2 and Endo‐F3 was successfully applied for a highly convergent chemoenzymatic synthesis of a full‐sized CD52 glycopeptide antigen carrying both terminal sialic acid and core fucose. This is the first report on endoglycosidases that are able to glycosylate α‐1,6‐fucosylated GlcNAc derivatives to form natural core‐fucosylated glycopeptides.
The Cooperative Effect in Ion‐Pair Recognition by a Ditopic Hemicryptophane Host
Authors: Perraud Olivier , Robert Vincent , Martinez Alexandre , Dutasta Jean‐Pierre
Published: March 2011

The heteroditopic hemicryptophane 1, which bears a tripodal anion binding site and a cation recognition site in the molecular cavity, proved to be an efficient ion‐pair receptor. The hemicryptophane host binds anions selectively depending on shape and hydrogen‐bond‐accepting ability. It forms an inclusion complex with the Me4N+ ion, which can simultaneously bind anionic species to provide anion@[1⋅Me4N+] complexes. The increased affinity of [1⋅Me4N+] for anionic species is attributed to a strong cooperative effect that arises from the properly positioned binding sites in the hemicryptophane cavity, thus allowing the formation of the contact ion pair. Density functional theory calculations were performed to analyze the Coulomb interactions of the ion pairs, which compete with the ion‐dipole ones, that originate in the ion–hemicryptophane contacts.
Switching Micellization of Pluronics in Water by CO2
Authors: Zhang Jianling , Han Buxing , Zhao Yueju , Li Jianshen , Yang Guanying
Published: March 2011

The micellization of amphiphilic molecules is an interesting topic from both theoretical and practical points of view. Herein we have studied the effects of compressed CO2 on the micellization of Pluronics in water by means of fluorescence, UV/Vis spectra, and small‐angle X‐ray scattering. It was found that CO2 can induce the micellization of Pluronics in water, and the micelle can return to the initial state of molecular dispersion after depressurization. Therefore, the micellization of Pluronics in water can be switched through the easy control of pressure. Different from the common micelles with hydrophobic cores, interestingly, this CO2‐induced micelle has an amphiphilic core, in which hydrophobic and hydrophilic domains coexist. On account of the ability to dissolve both polar and nonpolar components in the micellar core, the CO2‐induced micelles can improve the reagent compatibilities frequently encountered in various applications. In an attempt to address this advantage, this micelle was utilized as template to the one‐step synthesis of Au/silica core–shell composite nanoparticles. Furthermore, the underlying mechanism for the CO2‐induced micellization of Pluronics in water was investigated by a series of experiments.
Homoleptic Organometallic Anions of Ti, Zr, Hf, and Nb
Authors: El‐Kurdi Said , Seppelt Konrad
Published: March 2011

Reactions of C6H5Li and 4‐CH3C6H4Li with halides of Ti, Ir, Hf, and Nb lead to the formation of homoleptic organometallic anions of these metals. Owing to their thermal instability and their sensitivity towards H2O and O2, these compounds are characterized by single‐crystal structure determinations at low temperature, whereas other physical data could only be obtained occasionally. Three pentacoordinate complex anions [Ti(C6H5)5]−, [Ti(4‐CH3C6H4)5]−, and [Zr(C6H5)5]− have square‐pyramidal structures that display only slight deviations from the ideal geometry, in contrast to the already known structures of [Ti(CH5)5]−. The hexacoordinate complex anions [Zr(C6H5)6]2−, [Zr(4‐CH3C6H4)6]2−, [Nb(C6H5)6]2−, and [Nb(4‐CH3C6H4)6]2− all have trigonal‐prismatic structures, in accord with the known hexamethyl complex dianions. In contrast, the hexacoordinate complex anion [Hf(C6H5)6]2− has an octahedral or close to octahedral structure, in contrast to the known trigonal‐prismatic structures of [Ta(C6H5)6]− and [Ta(4‐CH3C6H4)6]−. A qualitative explanation for this structural variability is given.
Scale‐up and Detailed Process Analysis of a Membrane Assisted Esterification Reaction
Authors: Roth Tim , Hoffmann Achim , Kreis Peter , Lauterbach Sebastian
Published: March 2011

Die Kombination zwischen Reaktion und Pervaporation am Beispiel der Veresterung zu Propylpropionat wird untersucht. Eine Validierung des Prozessmodells erfolgt mit experimentellen Untersuchungen und es wird ein Scale‐up in den Technikumsmaßstab durchgeführt. Ausgehend von einer detaillierten Prozessanalyse werden optimale Bereiche für die Betriebs‐ und Strukturvariablen festgelegt und zwei mögliche Produktaufreinigungssequenzen vorgeschlagen.
Slip flow in doubly connected ducts
Authors: Wang C. Y.
Published: March 2011

The slip flows in a polygonal duct with a circular core and in an eccentric annular duct are studied by eigenfunction expansion and point match. It is found that the velocity distributions are quite different from those of no‐slip flow. The resistance (Poisueille number) decreases dramatically with increased slip.

On a étudié, par expansion de la fonction propre et par corrélation par points, les écoulements glissants dans une tuyère polygonale avec un cœur circulaire et dans une tuyère à anneaux excentriques. Les résultats montrent que la distribution des vitesses est différente par rapport aux écoulements non glissants. La résistance (en poiseuille) diminue considérablement avec un glissement accru. © 2011 Canadian Society for Chemical Engineering
Discovery and Biological Activity of 6BrCaQ as an Inhibitor of the Hsp90 Protein Folding Machinery
Authors: Audisio Davide , Messaoudi Samir , Cegielkowski Lukasz , Peyrat Jean‐François , Brion Jean‐Daniel , Methy‐Gonnot Délphine , Radanyi Christine , Renoir Jack‐Michel , Alami Mouâd
Published: March 2011

Heat shock protein 90 (Hsp90) is a significant target in the development of rational cancer therapy, due to its role at the crossroads of multiple signaling pathways associated with cell proliferation and viability. Here, a novel series of Hsp90 inhibitors containing a quinolein‐2‐one scaffold was synthesized and evaluated in cell proliferation assays. Results from these structure–activity relationships studies enabled identification of the simplified 3‐aminoquinolein‐2‐one analogue 2 b (6BrCaQ), which manifests micromolar activity against a panel of cancer cell lines. The molecular signature of Hsp90 inhibition was assessed by depletion of standard known Hsp90 client proteins. Finally, processing and activation of caspases 7, 8, and 9, and the subsequent cleavage of PARP by 6BrCaQ, suggest stimulation of apoptosis through both extrinsic and intrinsic pathways.
Oxidatively Activated DNA‐Modifying Agents for Selective Cytotoxicity
Authors: Li Guorui , Bell Tiffany , Merino Edward J.
Published: March 2011

DNA‐modifying agents are stalwarts of chemotherapeutic cancer treatments, but require significant design improvements to improve selectivity, minimize side effects, and for their widespread use to continue. Herein we present a novel design strategy in which DNA‐modifying agents contain an oxidizable leaving group and a nitrogen mustard. The agents form strong electrophiles specifically when oxidized. Activation, measured by hydrolysis, illustrates that oxidants increase reactivity 1700‐fold. Reaction in the presence of 2′‐deoxyguanosine leads to the formation of lesions. Cytotoxicity measured in HeLa cells showed that low IC50 values require an oxidizable hydroquinone and a nitrogen mustard fragment. Cytotoxicity measurements in 15 cancer cell lines demonstrates that oxidatively activated DNA‐modifying agents are highly selective, as the analogue tested has IC50 values less than 10 μM for only three of the 15 cell lines; in contrast, cisplatin is highly toxic to 13 of the 15 cell lines. The selective cytotoxicity of oxidatively activated DNA‐damaging agents could be useful against kidney cancer cells, as the 786‐O cell line model assay resulted in an IC50 value of 5 μM.
Parallel isosurface extraction for 3D data analysis workflows in distributed environments
Authors: D'Agostino D. , Clematis A. , Gianuzzi V.
Published: March 2011

In this paper we discuss the issues related to the development of efficient parallel implementations of the Marching Cubes algorithm, one of the most used methods for isosurface extraction, which is a fundamental operation for 3D data analysis and visualization. We present three possible parallelization strategies and we outline the pros and cons of each of them, considering isosurface extraction as stand‐alone operation or as part of a dynamic workflow. Our analysis shows that none of these implementations represents the most efficient solution for arbitrary situations. This is a major issue, because in many cases the quality of the service provided by a workflow depends on the possibility of selecting dynamically the operations to perform and, consequently, the more efficient basic building block for each stage. In this paper we present a set of guidelines that permits to achieve the highest performance for the extraction of isosurface in the most common situations, considering the characteristics of the data to process and of the workflow. These guidelines represent a suitable example to support the efficient configurations of workflows for 3D data processing in a dynamic and complex computing environment. Copyright © 2011 John Wiley & Sons, Ltd.
Detailed Characterization of the Dynamics of Ibuprofen in the Solid State by a Multi‐Technique NMR Approach
Authors: Carignani Elisa , Borsacchi Silvia , Geppi Marco
Published: March 2011

The internal rotations and interconformational jumps of ibuprofen in the solid state are fully characterized by the simultaneous analysis of a variety of low‐ and high‐resolution NMR experiments for the measurement of several 13C and 1H spectral and relaxation properties, performed at different temperatures and, in some cases, frequencies. The results are first qualitatively analyzed to identify the motions of the different molecular fragments and to assign them to specific frequency ranges (slow, <103 Hz; intermediate, 103–106 Hz; and fast, >106 Hz). In a second step, a simultaneous fit of the experimental data sets most sensitive to each frequency range is performed by means of suitable motional models to obtain, for each motion, values of correlation times and activation energies. The rotations of the three methyl groups around their ternary symmetry axes, which occur in the fast regime, are characterized by slightly different activation energies. Thanks to the simultaneous analysis of 1H and 13C data, the π‐flip of the dimeric structure made by the acidic groups is also identified and seen to occur in the fast regime. On the contrary, the π‐flip of the phenyl ring is found to occur in the slow motional regime, while the rotations of the isobutyl and propionic groups are frozen. The approach used appears to be of general applicability for studying the dynamics of small organic molecules.
Synthesis and tribological properties of NbSe3 nanofibers and NbSe2 microsheets
Authors: Tang Hua , Li Changsheng , Yang Xiaofei , Mo Chaochao , Cao Kesheng , Yan Fengyuan
Published: March 2011

NbSe3 nanofibers and NbSe2 sheets were prepared by solid state reaction. The as‐prepared products are characterized by powder X‐ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that the obtained NbSe3 nanofibers have a diameter in the range of 100–300 nm and length about 10 μm, while the NbSe2 sheets have a hexagon structure. The tribological properties of the as‐prepared NbSex powders as additives in HVI500 base oil were investigated on UMT‐2 multispecimen tribo‐tester. The wear scars were measured by VEECO WYKO NT1100 non‐contact optical profile testing instrument. It is found that the addition of both NbSex nanofibers/sheets improves the tribological properties of base oil. Furthermore, NbSe2 sheets exhibit better friction reduction and wear resistance properties than NbSe3 nanofibers in HVI500 base oil. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Basal cell adenoma: A diagnostic dilemma on fine needle aspiration cytology
Authors: Gupta Nalini , Bal Amanjit , Gupta Ashok Kumar , Rajwanshi Arvind
Published: March 2011

Basal cell adenoma (BCA) is a rare neoplasm which is one of the basaloid tumors of salivary gland. Basaloid tumors are the most difficult problem in salivary gland fine needle aspiration cytology (FNAC). There are various benign and malignant tumors such as; cellular pleomorphic adenoma, basal cell adenocarcinoma, adenoid cystic carcinoma, metastatic basal cell carcinoma, metastatic basaloid squamous carcinoma and small cell carcinoma in differential diagnosis. We present a case of BCA, membranous type in a 39‐year‐old female with right submandibular swelling misinterpreted as adenoid cystic carcinoma (ACC) on FNAC. Diagn. Cytopathol. 2011. © 2011 Wiley Periodicals, Inc.
Synthesis, Molecular Structure, and Physical Properties of the Complexes [{PhB(pz)2(CH2SMe)}2M] (M = MnII, FeII; pz = pyrazol‐1‐yl) Containing a Novel [N,N,S]‐Heteroscorpionate Ligand
Authors: Reus Christian , Ruth Kai , Tüllmann Sandor , Bolte Michael , Lerner Hans‐Wolfram , Weber Birgit , Holthausen Max C. , Wagner Matthias
Published: March 2011

Two transition metal complexes [L2M] {M = FeII (2), MnII (3)} of the novel [N,N,S] scorpionate ligand L = [PhB(pz)2(CH2SMe)]– have been synthesized and characterized by X‐ray crystallography, magnetic measurements, cyclic voltammetry, and various spectroscopic techniques. In the solid state, both complexes 2 and 3 possess a distorted octahedral ligand sphere, but adopt different configurations (2: cis; 3: trans). According to X‐ray diffraction data, Mössbauer spectroscopy, and SQUID measurements, compound 2 exists as low‐spin complex in the solid state at temperatures T ≤ 20 °C (μeff ≈ 0.5 μB). Upon heating, the magnetic moment μeff increases continuously to a value of 1.8 μB at 90 °C, which indicates a temperature dependent high‐spin ↔ low‐spin transition above room temp. Solutions of 2 in CDCl3 showed paramagnetic behavior at 25 °C (μeff = 3.1 μB; Evans NMR method). Cyclic voltammetry (CH2Cl2, [Bu4N][PF6]; vs. FcH/FcH+) on 2 reveals a reversible FeII/FeIII redox transition at E1/2 = –0.16 V. Density functional theory (B3LYP‐D/def2‐TZVPP//B3LYP‐D/SVP level) has been used to evaluate relative energies of the cis and trans isomers of 2 in their high‐spin and low‐spin states. Theoretical and experimental investigations have been extended to the related literature‐known homoleptic FeII complexes [{PhB(pz)3}2Fe], [{PhB(pz)(CH2SMe)2}2Fe], and [{PhB(CH2SMe)3}2Fe]. The following order of ligand‐field strengths has been established: [PhB(CH2SMe)3]– < [PhB(pz)(CH2SMe)2]– < [PhB(pz)2(CH2SMe)]– < [PhB(pz)3]–. The only significant deviation from this systematic behavior became evident for the unexpectedly low solution magnetic moment of [{PhB(CH2SMe)3}2Fe], which finds no parallel in the solid state. Computed spin‐state splittings for the entire series of complexes, however, confirm the trend in solution magnetic moments and we relate the disaccording experimental observations to the presence of a second stereoisomer in crystals of [{PhB(CH2SMe)3}2Fe] which increases the paramagnetism of solid‐state samples of this complex.
Selective Chemical Oxidation of Risperidone: A Straightforward and Cost‐Effective Synthesis of Paliperidone
Authors: Riva Renata , Banfi Luca , Castaldi Graziano , Ghislieri Diego , Malpezzi Luciana , Musumeci Francesca , Tufaro Roberto , Rasparini Marcello
Published: March 2011

A very short and cost‐effective synthesis of the commercial drug paliperidone has been achieved starting from its parent compound risperidone, through a thoroughly optimized oxidation with air under basic conditions.
Copper‐Catalyzed Direct Synthesis of 3‐Arylindoles
Authors: Murru Siva , Gallo August A. , Srivastava Radhey S.
Published: March 2011

A direct method for the preparation of various 3‐arylindoles from their corresponding nitrosoarenes has been developed. Various substituted nitrosoarenes and alkynes were employed to obtain substituted indoles by using a CuII–Cu0 catalytic system. This is a two‐step method that involves annulation of the nitrosoarene and alkyne followed by deoxygenation to give 3‐arylindoles.
High yield and cost‐effective production of poly(γ‐glutamic acid) with Bacillus subtilis
Authors: Huang Jin , Du Yinming , Xu Guohua , Zhang Huili , Zhu Fan , Huang Lei , Xu Zhinan
Published: March 2011

Poly(γ‐glutamic acid) (γ‐PGA) is a promising biopolymer with many potential industrial and pharmaceutical applications. To reduce the production costs, the effects of yeast extract and L‐glutamate in the substrate for γ‐PGA production were investigated systematically at shake flask scale. The results showed that lower concentrations of yeast extract (40 g/L) and L‐glutamate (30 g/L) were beneficial for the cost‐effective production of γ‐PGA in the formulated medium. By maintaining the glucose concentration in the range of 3–10 g/L via a fed‐batch strategy in a 10‐L fermentor, the production of γ‐PGA was greatly improved with the highest γ‐PGA concentration of 101.1 g/L, a productivity of 2.19 g/L·h and a yield of 0.57 g/g total substrate, which is about 1.4‐ to 3.2‐fold higher than those in the batch fermentation. Finally, this high‐density fermentation process was successfully scaled up in a 100‐L fermentor. The present work provides a powerful approach to produce this biopolymer as a bulk chemical in large scale.
The human carcinogen aristolochic acid i is activated to form DNA adducts by human NAD(P)H:quinone oxidoreductase without the contribution of acetyltransferases or sulfotransferases
Authors: Stiborová Marie , Mareîs Jaroslav , Frei Eva , Arlt Volker M. , Martínek Václav , Schmeiser Heinz H.
Published: March 2011

Ingestion of aristolochic acid (AA) is associated with development of urothelial tumors linked with AA nephropathy and is implicated in the development of Balkan endemic nephropathy‐associated urothelial tumors. We investigated the efficiency of human NAD(P)H:quinone oxidoreductase (NQO1) to activate aristolochic acid I (AAI) and used in silico docking, using soft–soft (flexible) docking procedure, to study the interactions of AAI with the active site of human NQO1. AAI binds to the active site of NQO1 indicating that the binding orientation allows for direct hydride transfer (i.e., two electron reductions) to the nitro group of AAI. NQO1 activated AAI, generating DNA adduct patterns reproducing those found in urothelial tissues from humans exposed to AA. Because reduced aromatic nitro‐compounds are often further activated by sulfotransferases (SULTs) or N,O‐acetlytransferases (NATs), their roles in AAI activation were investigated. Our results indicate that phase II reactions do not play a major role in AAI bioactivation; neither native enzymes present in human hepatic or renal cytosols nor human SULT1A1, ‐1A2, ‐1A3, ‐1E, or ‐2A nor NAT1 or NAT2 further enhanced DNA adduct formation by AAI. Instead under the in vitro conditions used, DNA adducts arise by enzymatic reduction of AAI through the formation of a cyclic hydroxamic acid (N‐hydroxyaristolactam I) favored by the carboxy group in peri position to the nitro group without additional conjugation. These results emphasize the major importance of NQO1 in the metabolic activation of AAI and provide the first evidence that initial nitroreduction is the rate limiting step in AAI activation. Environ. Mol. Mutagen., 2011. © 2011 Wiley‐Liss, Inc.
Role of DNA polymerase beta in the genotoxicity of arsenic
Authors: Lai Yanhao , Zhao Wei , Chen Chen , Wu Mei , Zhang Zunzhen
Published: March 2011

Arsenic, an important hazard in the environment, is associated with human cancer and other degenerative diseases. However, the mechanisms underlying arsenic hazardous effects remain unclear. It has been reported arsenic exposure can result in increased cellular reactive oxygen species and oxidative DNA damage. This suggests DNA base excision repair (BER), the major pathway for repairing oxidative DNA damage, may be involved in combating arsenic hazardous effects. As a critical repair enzyme in BER, DNA polymerase beta (Pol β) might play an essential role in reducing arsenic toxicity. To test this hypothesis, we evaluated arsenic‐induced cytotoxic and genotoxic effects under Pol β deficiency. Our results demonstrated that the viability of Pol β‐deficient mouse embryonic fibroblasts was much lower than that of Pol β wild‐type cells after treatment with arsenite (As3+). An increased level of DNA damage and significantly delayed arsenite‐induced DNA damage repair in Pol β‐deficient cells indicated reduced repair of DNA lesions under Pol β deficiency. This was consistent with the increase in the frequency of micronuclei (MN), an indicator of chromosomal breakage, which was also observed in Pol β‐deficient cells treated with arsenite. In contrast, cells harboring overexpressed Pol β resulted in a lower level of DNA damage and MN than Pol β wild‐type cells, indicating overexpression of the enzyme can combat arsenic‐induced genotoxic effects. In conclusion, our results indicate an important role for Pol β in repairing arsenite‐induced DNA damage and maintaining chromosomal integrity and further suggest deficiency of BER may be involved in arsenic genotoxicity and carcinogenicity. Environ. Mol. Mutagen., 2011. © 2011 Wiley‐Liss, Inc.
Comparison of mercury concentrations in landlocked, resident, and sea-run fish (Salvelinus spp.) from Nunavut, Canada
Authors: Swanson Heidi , Gantner Nikolaus , Kidd Karen A , Muir D.C.G , Reist James D
Published: March 2011

Mercury concentrations ([Hg]) in Arctic food fish often exceed guidelines for human subsistence consumption. Previous research on two food fish species, Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush), indicates that anadromous fish have lower [Hg] than nonanadromous fish, but there have been no intraregional comparisons. Also, no comparisons of [Hg] among anadromous (sea-run), resident (marine access but do not migrate), and landlocked (no marine access) life history types of Arctic char and lake trout have been published. Using intraregional data from 10 lakes in the West Kitikmeot area of Nunavut, Canada, we found that [Hg] varied significantly among species and life history types. Differences among species–life history types were best explained by age-at-size and C:N ratios (indicator of lipid); [Hg] was significantly and negatively related to both. At a standardized fork length of 500 mm, lake trout had significantly higher [Hg] (mean 0.17 µg/g wet wt) than Arctic char (0.09 µg/g). Anadromous and resident Arctic char had significantly lower [Hg] (each 0.04 µg/g) than landlocked Arctic char (0.19 µg/g). Anadromous lake trout had significantly lower [Hg] (0.12 µg/g) than resident lake trout (0.18 µg/g), but no significant difference in [Hg] was seen between landlocked lake trout (0.21 µg/g) and other life history types. Our results are relevant to human health assessments and consumption guidance and will inform models of Hg accumulation in Arctic fish. Environ. Toxicol. Chem. 2011; 30:1459–1467. © 2011 SETAC
TCP flow aware adaptive path switching in diffserv enabled MPLS networks
Authors: Alparslan Onur , Akar Nail , Karasan Ezhan
Published: March 2011

We propose an adaptive flow‐level multi‐path routing‐based traffic engineering solution for an IP backbone network carrying TCP/IP traffic. Incoming TCP flows are switched between two explicitly routed paths, namely the primary and secondary paths (PP and SP), for resilience and potential goodput improvement at the TCP layer. In the proposed architecture, PPs receive a preferential treatment over SPs using differentiated services mechanisms. The reason for this choice is not for service differentiation but for coping with the detrimental knock‐on effect stemming from the use of longer SP that is well known for conventional network load balancing algorithms. Moreover, both paths are congestion‐controlled using Explicit Congestion Notification marking at the core and Additive Increase Multiplicative Decrease rate adjustment at the ingress nodes. The delay difference between PP and SP is estimated using two per‐egress rate‐controlling buffers maintained at the ingress nodes for each path, and this delay difference is used to determine the path over which a new TCP flow will be routed. We perform extensive simulations using ns‐2 in order to demonstrate the viability of the proposed distributed adaptive multi‐path routing method in terms of per‐flow TCP goodput. The proposed solution consistently outperforms the single‐path routing policy and provides substantial per‐flow goodput gains under poor PP conditions. Moreover, highest goodput improvements under the proposed scheme are achieved by flows that receive the lowest goodputs with single‐path routing, while the performance of the flows with high goodputs with single‐path routing does not deteriorate with the proposed path switching technique. Copyright © 2011 John Wiley & Sons, Ltd.
Stabilized finite element method based on local preconditioning for unsteady compressible flows in deformable domains with emphasis on the low Mach number limit application
Authors: López Ezequiel J. , Nigro Norberto M. , Sarraf Sofía S. , Damián Santiago Márquez
Published: March 2011

Flows with low Mach numbers represent a limit situation in the solution of compressible flows. The preconditioning of flow equations is one of the classical approaches proposed to capture the solution in the low Mach number limit. In this method, the time derivatives are premultiplied by a suitable preconditioning matrix in order to achieve a well‐conditioned system by means of the scaling of the system eigenvalues. Hence, the modified equations have only steady‐state solutions in common with the original system. For the application of these methods to unsteady problems, the dual time‐stepping technique has emerged, where the physical time derivative terms are treated as source and/or reactive terms. The use of a preconditioning matrix defined to compute steady‐state solutions may not be a good choice for unsteady problems, as showed by Vigneronit et al. (European Conference on Computational Fluid Dynamics, 2006). However, such matrices can be adapted to perform the computation of transient flows by means of the appropriate redefinition of some coefficients. The application of a ‘steady‐state’ preconditioning matrix to unsteady problems with an ALE (Arbitrary Lagrangian Eulerian) approach is presented. The equations are discretized in space using a stabilized Finite Element method and in time using finite differences. The preconditioning of the governing equations is not applied in the numerical scheme but is used, through the eigenvalues of the preconditioned system, to design appropriately the stabilization term. Several test cases are solved, including incompressible flows and the in‐cylinder flow in a motored opposed‐piston engine. Copyright © 2011 John Wiley & Sons, Ltd.
Highly Sulphonated Multiblock‐co‐polymers for Direct Methanol Fuel Cells
Authors: Krajinovic K. , Kaz T. , Haering T. , Gogel V. , Kerres J.
Published: March 2011

Multiblock‐co‐polymers with different ion exchange capacities were synthesised by nucleophilic aromatic step‐growth polycondensation of hydrophilic and hydrophobic oligomers. The main focus of this work was to investigate the dependence of oligomer reactivity on molecular weight and how the reaction conditions need to be changed to obtain high‐molecular multiblock‐co‐polymers, consisting of long block segments. Multiblock‐co‐polymers composed of short oligomers could be synthesised under mild reaction conditions. The coupling of longer oligomers required more basic reaction conditions, because the reactive functional end‐groups were shielded by the long oligomeric main chain. The membranes were investigated further in terms of their properties relevant for use as polymer electrolyte membrane in direct methanol fuel cells (DMFCs). The mechanical stability of the acidic polymers was improved through ionical crosslinking with basic polybenzimidazole. A series of membranes was tested in a self‐ and in an air‐breathing DMFC.
The relationship between currency carry trades and U.S. stocks
Authors: Tse Yiuman , Zhao Lin
Published: March 2011

The article examines the relationship between daily returns of currency carry trades and U.S. stocks from January 1995 through September 2010. Carry trade and stock returns are highly correlated with no Granger‐causality in either direction. An EGARCH model shows that significant volatility spillovers flow from the stock market to the carry‐trade market, but not vice versa. The markets are more correlated in periods of high volatility. Volatilities in both markets also increase more with negative innovations than positive innovations. A sectoral analysis of the index suggests that volatilities of cyclical stocks have more impact than noncyclical stocks on carry trades.
Change in stress and social support as predictors of cognitive decline in older adults with and without depression
Authors: Dickinson Whitney J. , Potter Guy G. , Hybels Celia F. , McQuoid Douglas R. , Steffens David C.
Published: March 2011

Objective

The relationship between stress, social support, and cognition in geriatric depression is complex. In this study, we sought to examine whether an increase in stressful life events or a decrease in social support would lead to subsequent cognitive decline among older adults with and without depression.

Methods

The sample consisted of 112 depressed and 101 non‐depressed older adults who enrolled in the Neurocognitive Outcomes of Depression in the Elderly (NCODE) study. Participants were assessed clinically, agreed to interviews focusing on stressful life events and social support, and underwent a battery of neuropsychological tests annually. Our global measure of cognition was the Consortium to Establish a Registry in Alzheimer's disease Total Score (CERAD TS).

Results

We found that a decline in the total number of stressors was associated with a subsequent improvement on CERAD TS. In terms of social support, decreased social interaction, and instrumental social support predicted decline in cognitive performance. These relationships were significant even after controlling for depression status, age, education, and sex.

Conclusions

These findings extend prior research on the importance of social factors in aging and depression which have largely focused on mood‐related outcomes. Future confirmatory studies are needed. In addition, biological and other studies should be conducted to further our understanding of the relationship between stress, social support and cognition in older adults with and without depression. Copyright © 2011 John Wiley & Sons, Ltd.
Interleukin-32: A new proinflammatory cytokine involved in hepatitis C virus-related liver inflammation and fibrosis
Authors: Moschen Alexander R. , Fritz Teresa , Clouston Andrew D. , Rebhan Ilka , Bauhofer Oliver , Barrie Helen D. , Powell Elizabeth E. , Kim Soo-Hyun , Dinarello Charles A. , Bartenschlager Ralf , Jonsson Julie R. , Tilg Herbert
Published: March 2011

Interleukin 32 (IL-32) is a recently described proinflammatory cytokine that activates p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB), thereby inducing proinflammatory cytokines such as IL-1β and tumor necrosis factor alpha (TNF-α). We investigated the role of IL-32 in patients with chronic hepatitis C virus (HCV) infection. Steady-state hepatic messenger RNA (mRNA) levels of IL-32 were determined in a cohort of 90 subjects; anti-IL-32 staining was used in a second cohort of 132 consecutive untreated chronic HCV patients. Correlations with histological features of steatosis, inflammation, and fibrosis were made. In vitro, endogenous IL-32 in monocytes and in the human hepatoma cell line Huh-7.5 were examined. The effects of IL-32-overexpression and IL-32-silencing on HCV replication were studied using HCV luciferase reporter viruses. There were highly significant positive associations between hepatic IL-32 mRNA expression and liver steatosis, inflammation, fibrosis, smooth muscle actin (SMA) area, and serum alanine aminotransferase (ALT) levels. IL-32 protein expression was positively associated with portal inflammation, SMA area, and ALT. In vitro, IL-1β and TNF-α significantly induced IL-32 expression in human Huh-7.5 cells. Alone, stimulation with interferon alpha (IFN-α) did not induce IL-32 expression in Huh-7.5. However, IFN-α exerted a significant additive effect on TNF-α-induced but not IL-1β-induced IL-32 expression, particularly in CD14+ monocytes. This effect was dependent both on NF-κB and Jak/STAT signaling. Viral infection of Huh-7.5 cells resulted in a significant (11-fold) induction of IL-32 mRNA expression. However, modulation of IL-32 in Huh-7.5 cells by overexpression or silencing did not influence HCV virus replication as determined by luciferase assays. Conclusion: IL-32 is a novel proinflammatory cytokine involved in HCV-associated liver inflammation/fibrosis. IL-32 is expressed by human hepatocytes and hepatoma cells and its expression is regulated by proinflammatory stimuli. (HEPATOLOGY 2011;)
Biomechanical and histologic evaluation of tissue engineered ligaments using chitosan and hyaluronan hybrid polymer fibers: A rabbit medial collateral ligament reconstruction model
Authors: Irie Toru , Majima Tokifumi , Sawaguchi Naohiro , Funakoshi Tadanao , Nishimura Shin‐ichiro , Minami Akio
Published: March 2011

In this study, we used a rabbit medial collateral ligament reconstruction model to evaluate a novel chitosan‐based hyaluronan hybrid polymer fiber scaffold for ligament tissue engineering and to examine whether mechanical forces exerted in an in vivo model increased extracellular matrix production by seeded fibroblasts. Scaffolds were used 2 weeks after incubation with fibroblasts obtained from the same rabbit in a cell‐seeded scaffold (CSS) group and without cells in a noncell‐seeded scaffold (NCSS) group. At 3, 6, and 12 weeks after surgery, the failure loads of the engineered ligaments in the CSS groups were significantly greater than those in the NCSS groups. At 6 weeks after surgery, the reconstructed tissue of the CSS group was positive for type I collagen, whereas that in the NCSS group was negative for type I collagen. At 12 weeks after surgery, the reconstructed tissue stained positive for type I collagen in the CSS group, but negative in the NCSS group. Our results indicate that the scaffold material enhanced the production of type I collagen and led to improved mechanical strength in the engineered ligament in vivo. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Controlling cell growth on titanium by surface functionalization of heptylamine using a novel combined plasma polymerization mode
Authors: Zhao Jing H. , Michalski Wojtek P. , Williams Catherine , Li Li , Xu Hong‐Sheng , Lamb Peter R. , Jones Scott , Zhou Yan M. , Dai Xiujuan J.
Published: March 2011

A novel bio‐interface, produced by a combined plasma polymerization mode on a titanium (Ti) surface, was shown to enhance osteoblast growth and reduce fibroblast cell growth. This new method can securely attach a tailored interface to difficult materials such as Ti or ceramics. Here a more stable and higher density of NH2 functional groups is able to withstand sterilization in ethanol. The biocompatibility, in terms of cell attachment and actin cytoskeleton development, was markedly improved in vitro, compared with untreated Ti surfaces and samples treated by other plasma modes. It gave a boosted (approximately six times higher) cellular response of osteoblasts in their initial adhesion stage. These factors should increase the formation of new bone around implants (reducing healing time), promoting osseointegration and thereby increasing implantation success rates. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Development of chitosan–vancomycin antimicrobial coatings on titanium implants
Authors: Swanson T. E. , Cheng X. , Friedrich C.
Published: March 2011

Techniques for titanium surface modification have been studied for applications in orthopedic implants specifically for local drug delivery. The extensive research in surface modification is driving the development of devices that integrate infection prevention, osseointegration, and functionality in a structural role. In this study, vancomycin was applied to modified titanium surfaces to determine the effect of surface morphology on drug loading and release profiles. The antimicrobial effectiveness of the released vancomycin was evaluated and found to have a similar effect as the standard vancomycin. The engineered surfaces included sandblasted, sandblasted acid etched, electrochemically etched, and sandblasted electrochemically etched. The antibiotic release was observed to be independent of the measured surface parameters of the engineered surfaces. The development of an implantable device in which the surface morphology can be tailored for an application with no effect on the total drug released would be beneficial to more precisely control the biological response while maintaining local drug delivery for infection prevention. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Influence of a 3-year exercise intervention program on fracture risk, bone mass, and bone size in prepubertal children
Authors: Löfgren Bjarne , Detter Fredrik , Dencker Magnus , Stenevi-Lundgren Susanna , Nilsson Jan-Åke , Karlsson Magnus K
Published: March 2011

Published prospective pediatric exercise intervention studies are short term and use skeletal traits as surrogate endpoints for fractures, whereas other reports infer exercise to be associated with more trauma and fractures. This prospective, controlled exercise intervention study therefore followed both skeletal traits and fracture risk for 36 months. Fractures were registered in children aged 7 to 9 years; there were 446 boys and 362 girls in the intervention group (2129 person-years) and 807 boys and 780 girls in the control group (4430 person-years). The intervention included school physical education of 40 minutes per day for 3 years. The control children achieved the Swedish standard of 60 minutes per week. In a subsample of 76 boys and 48 girls in the intervention group and 55 boys and 44 girls in the control group, bone mineral content (BMC, g) and bone width (cm) were followed in the lumbar spine and hip by dual-energy X-ray absorptiometry (DXA). The rate ratio (RR) for fractures was 1.08 (0.71, 1.62) [mean (95% confidence interval)]. In the DXA-measured children, there were no group differences at baseline in age, anthropometrics, or bone traits. The mean annual gain in the intervention group in lumbar spine BMC was 0.9 SD higher in girls and 0.8 SD higher in boys (both p < .001) and in third lumbar vertebra width 0.4 SD higher in girls and 0.3 SD higher in boys (both p < .05) than in control children. It is concluded that a moderately intense 3-year exercise program in 7- to 9-year-old children increases bone mass and possibly also bone size without increasing fracture risk. © 2011 American Society for Bone and Mineral Research
HSP75 protects against cardiac hypertrophy and fibrosis
Authors: Zhang Yan , Jiang Ding‐Sheng , Yan Ling , Cheng Kuo‐Ju , Bian Zhou‐Yan , Lin Guo‐Sheng
Published: March 2011

Cardiac hypertrophy, a major determinant of heart failure, is associated with heat shock proteins (HSPs). HSP75 has been reported to protect against environmental stresses; however, its roles in cardiac hypertrophy remain unclear. Here, we generated cardiac‐specific inducible HSP75 transgenic mice (TG) and cardiac hypertrophy was developed at 4 weeks after aortic banding in TG mice and wild‐type littermates. The results revealed that overexpression of HSP75 prevented cardiac hypertrophy and fibrosis as assessed by heart weight/body weight ratio, heart weight/tibia length ratio, echocardiographic and hemodynamic parameters, cardiomyocyte width, left ventricular collagen volume, and gene expression of hypertrophic markers. Further studies showed that overexpression of HSP75 inhibited the activation of TAK/P38, JNK, and AKT signaling pathways. Thus, HSP75 likely reduces the hypertrophy and fibrosis induced by pressure overload through blocking TAK/P38, JNK, and AKT signaling pathways. J. Cell. Biochem. 112: 1787–1794, 2011. © 2011 Wiley‐Liss, Inc.
C/EBPβ regulates dexamethasone‐induced muscle cell atrophy and expression of atrogin‐1 and MuRF1
Authors: Gonnella Patricia , Alamdari Nima , Tizio Steven , Aversa Zaira , Petkova Victoria , Hasselgren Per‐Olof
Published: March 2011

Muscle wasting in catabolic patients is in part mediated by glucocorticoids and is associated with increased expression and activity of the transcription factor C/EBPβ. It is not known, however, if C/EBPβ is causally linked to glucocorticoid‐induced muscle atrophy. We used dexamethasone‐treated L6 myoblasts and myotubes to test the role of C/EBPβ in glucocorticoid‐induced expression of the muscle‐specific ubiquitin ligases atrogin‐1 and MuRF1, protein degradation, and muscle atrophy by transfecting cells with C/EBPβ siRNA. In myoblasts, silencing C/EBPβ expression with siRNA inhibited dexamethasone‐induced increase in protein degradation, atrogin‐1 and MuRF1 expression, and muscle cell atrophy. Similar effects of C/EBPβ siRNA were seen in myotubes except that the dexamethasone‐induced increase in MuRF1 expression was not affected by C/EBPβ siRNA in myotubes. In additional experiments, overexpressing C/EBPβ did not influence atrogin‐1 or MuRF1 expression in myoblasts or myotubes. Taken together, our observations suggest that glucocorticoid‐induced muscle wasting is at least in part regulated by C/EBPβ. Increased C/EBPβ expression alone, however, is not sufficient to upregulate atrogin‐1 and MuRF1 expression. J. Cell. Biochem. 112: 1737–1748, 2011. © 2011 Wiley‐Liss, Inc.
EGFR signaling suppresses osteoblast differentiation and inhibits expression of master osteoblastic transcription factors Runx2 and osterix
Authors: Zhu Ji , Shimizu Emi , Zhang Xianrong , Partridge Nicola C. , Qin Ling
Published: March 2011

The epidermal growth factor receptor (EGFR) and its ligands regulate key processes of cell biology, such as proliferation, survival, differentiation, migration, and tumorigenesis. We previously showed that, EGFR signaling pathway is an important bone regulator and it primarily plays an anabolic role in bone metabolism. In this study, we demonstrated that EGF‐like ligands strongly inhibited osteoblast differentiation and mineralization in several lines of osteoblastic cells. Real‐time RT‐PCR and promoter reporter assays revealed that EGF‐like ligands suppressed the expression of both early and late bone marker genes at the transcriptional level in the differentiating osteoblasts via an EGFR‐dependent manner. This inhibitory effect of EGFR signaling was not dependent on its mitogenic activity. Furthermore, we demonstrated that EGFR signaling reduced the expression of two major osteoblastic transcription factors Runx2 (type II) and Osterix in osteoblast differentiating cells. EGFR‐induced decrease in Runx2 transcriptional activity was confirmed by Runx2 reporter and chromatin immunoprecipitation assays. EGFR signaling increased the protein amounts of transcription co‐repressors HDAC4 and 6 and over‐expression of HDAC4 decreased Runx2 amount in differentiating osteoblasts, implying that HDACs contribute to the down‐regulation of Runx2 by EGFR. Moreover, activation of EGFR in undifferentiated osteoprogenitors attenuated the expression of early bone markers and Osterix and decreased Runx2 protein amounts. Together with our previous data, that EGFR stimulates osteoprogenitor proliferation and that blocking EGFR activity in osteoblast lineage cells results in fewer osteoprogenitors and an osteopenic phenotype, we conclude that EGFR signaling is important for maintaining osteoprogenitor population at an undifferentiated stage. J. Cell. Biochem. 112: 1749–1760, 2011. © 2011 Wiley‐Liss, Inc.