bluuebunny/crossref_metadata_2025 huggingface dataset:
The η2 Complex of Nickel Bis(diphenylphosphanyl)propane with Fullerene: {Ni(dppp)(η2‐C60)}·(Solvent) Obtained by Reduction
Authors: Konarev Dmitri V. , Khasanov Salavat S. , Yudanova Evgeniya I. , Lyubovskaya Rimma N.
Published: January 2011

The η2 complex of nickel bis(diphenylphosphanyl)propane with fullerene, {Ni(dppp)(η2‐C60)}·(C6H14)0.84·(C6H4Cl2)0.16 (1) (C6H14: hexane, C6H4Cl2: o‐dichlorobenzene), has been obtained by reduction of the Ni(dppp)Cl2 and C60 mixture with sodium fluorenone in o‐dichlorobenzene and slow precipitation of the single crystals by diffusion of hexane. Nickel coordinates to the 6–6 bond of C60 by η2‐coordination to form Ni–C(C60) bonds with a length of 1.948–1.951(2) Å, which are the shortest M–C bonds among known η2 complexes of fullerenes. The 6–6 bond length [1.488(3) Å] where the Ni atom is coordinated is noticeably longer than the average length of other 6–6 bonds in C60 [1.388(2) Å]. Coordination of nickel to C60 results in the splitting of two bands for two IR‐active modes of C60 into three bands, because of the lower symmetry of C60, and a noticeable shift in the F1u(4) mode of C60 to lower frequencies, as a result of π back‐donation. The dark green complex manifests two absorption bands at 664 and 890 nm in the visible range. The complex is EPR silent since only a weak narrow signal with g = 2.0000 and ΔH = 0.17 mT was found in the EPR spectrum of 1 at room temperature, which originates from about 0.1 % of spins of the total amount of C60.
Unraveling the Electronic Properties of the Photoinduced States of the H‐Cluster in the [FeFe] Hydrogenase from D. desulfuricans
Authors: Silakov Alexey , Reijerse Edward J. , Lubitz Wolfgang
Published: January 2011

[FeFe] hydrogenases belong to a class of enzymes that catalyze the reversible heterolytic splitting of molecular hydrogen. The structure of their active site is rather unusual consisting of a CN– and CO‐coordinated [2Fe] subcluster connected to a ferredoxin‐like [4Fe4S] subcluster through one of the Cys‐S ligands. The iron, distal to the “cubane” has an open coordination site that is believed to be the substrate binding site. In the active forms of the H‐cluster, this site can be inhibited by carbon monoxide, which results in an EPR‐active state, called Hox‐CO. At temperatures below 100 K, illumination in the visible range causes conversion of this state into two other EPR‐active states. One of these is the Hox state, i.e. the catalytically active form, characterized by a vacant external coordination site. The other state (HLI) is probably characterized by dissociation of the bridging CO ligand. The photodissociation of the Hox‐CO state provides a convenient way to study changes in the electronic structure caused by dissociation of various CO ligands. In this article, we show results of an advanced EPR study of the light‐induced species of the active site, in particular, HLI. On the basis of the resolved hyperfine signals of the 1H, 14N, 13C, and 57Fe nuclei, we obtained a detailed picture of the electronic structure of the H‐cluster. It turned out that dissociation of the bridging CO ligand causes a major rearrangement of the structure of the H‐cluster and large changes in the distribution of the unpaired spin. Moreover, it appears that the extent of spin delocalization in the 2Fe subcluster in the case of HLI is intermediate between that of Hox and Hox‐CO.
Relaxometric Study of a Series of Monoaqua GdIIIComplexes of Rigidified EGTA‐Like Chelators and Their Noncovalent Interaction with Human Serum Albumin
Authors: Botta Mauro , Avedano Stefano , Giovenzana Giovanni Battista , Lombardi Alberto , Longo Dario , Cassino Claudio , Tei Lorenzo , Aime Silvio
Published: January 2011

The lanthanide(III) complexes of five EGTA [ethyleneglycol‐bis(2‐aminoethyl) ether‐N,N,N′,N′‐tetraacetic acid] derivatives fused with aromatic (benzene:L1; naphthalene:L2) and functionalized aromatic (L3–L5) moieties on the oxyethylene bridge were investigated in aqueous solution.1H and13C NMR spectra of the LaIIIand LuIIIcomplexes ofL1andL2indicate that the structural differences across the Ln series found for the [Ln(EGTA)]–complexes is maintained in the new derivatives. The presence of the aromatic moiety favours an increased stereochemical rigidity, as assessed by VT13C NMR spectra. Temperature‐dependent17O NMR spectroscopic data and 1/T11H NMRD profiles of the GdIIIcomplexes ofL1–L3were measured and globally analyzed to obtain the parameters influencing the water exchange rate,kex, and rotational dynamics. Thekexvalues are ca. twice as high as the corresponding value of [Gd(EGTA)]–and very close to optimal. The lipophilic complexes [GdL4]–and [GdL5]–form micellar aggregates whose NMRD profiles were measured and analyzed in terms of a model that allows separation of global motion and local rotation. The noncovalent binding interaction of the complexes to human serum albumin and the relaxivity of the macromolecular conjugates were investigated with relaxometric techniques at 20 MHz and 298 K, and the importance of a restricted local motion of the complex at the binding site for attaining large relaxivity enhancement outlined. Theoretical docking simulations and relaxometric competition experiments provided insights into the binding modes of the complexes.
Carbasugar Analogues of Galactofuranosides: Pseudodisaccharide Mimics of Fragments of Mycobacterial Arabino­galactan
Authors: Frigell Jens , Pearcey Jean A. , Lowary Todd L. , Cumpstey Ian
Published: January 2011

A partially protected carbasugar analogue of β‐galactofuranose was converted into an α‐galacto‐configured 1,2‐epoxide, which was opened by alcohols under Lewis acid catalysis with regioselective attack at C‐1 to give β‐galacto‐configured C‐1 ethers. Using OH‐5 and OH‐6 carbagalactofuranose derivatives as nucleophiles, we synthesised pseudodisaccharide analogues of substructures of the arabinogalactan from M. tuberculosis. The dicarba analogue of the disaccharide Galf(β1→5)Galf was found to moderately inhibit the action of GlfT2 galactofuranosyl transferase from M. tuberculosis.
A Highly Efficient, Large‐Scale, Asymmetric Direct Aldol Reaction Employing Simple Threonine Derivatives as Recoverable Organocatalysts in the Presence of Water
Authors: Wu Chuanlong , Fu Xiangkai , Li Shi
Published: January 2011

A one‐step O‐acylation of threonine resulted in a simple and readily available threonine‐surfactant organocatalyst that could efficiently catalyze the direct asymmetric aldol reactions of cyclic and acyclic ketones with a series of aromatic aldehydes in the presence of water at room temperature with good yields (up to 99 %), diastereoselectivities (up to 99:1), and enantiomeric excesses (>99 %). The catalyst can beeasily recovered and reused with no decrease of enantioselectivity after six cycles. This novel catalyst can be efficiently used in large‐scale reactions, with the enantioselectivity being maintained at the same level, which offers great possibilities for application in industry.
Phospha‐Michael‐Type Reactions between 1,2‐Diaza‐1,3‐dienes and Bidentate Nucleophiles: Formation of New Mono‐ and Diylides and their Elaboration to Heterocycles
Authors: Boga Carla , Zanna Nicola , Attanasi Orazio A. , Baccolini Graziano , De Crescentini Lucia , Forlani Luciano , Mantellini Fabio , Nicolini Simona , Micheletti Gabriele , Tozzi Silvia
Published: January 2011

Phospha‐Michael additions of a series of methylene‐bridged phosphorus bidentate nucleophiles to 1,2‐diaza‐1,3‐dienes gave monoadducts and bisadducts in high yields under mild conditions. In particular, a series of new ylides and symmetrical diylides have been obtained from bis(diphenyl)phosphanes. The use of diphenylphosphanylamino derivatives gave, through phospha‐Michael addition, ylide intermediates that underwent spontaneous intramolecular attack by the amino group belonging to the Michael donor reagent moiety, thus giving access to new heterocycles.
Nanocomposite Carbon‐PDMS Material for Chip‐Based Electrochemical Detection
Authors: Brun Mathieu , Chateaux Jean‐François , Deman Anne‐Laure , Pittet Patrick , Ferrigno Rosaria
Published: January 2011

This paper presents an alternative approach to create low‐cost and patternable carbon electrodes suitable for microfluidic devices. The fabrication and the electrochemical performances of electrodes made of Polydimethylsiloxane doped with commercially available carbon black (C‐PDMS) are described. Conductivity and electrochemical measurements performed on various carbon to PDMS ratios showed that electrodes with suitable electrochemical properties were obtained with a ratio of 25 %.
Electrochemical Glutathione Sensor Based on Electrochemically Deposited Poly‐m‐aminophenol
Authors: Oztekin Yasemin , Ramanaviciene Almira , Ramanavicius Arunas
Published: January 2011

Preparation and characterization of electrodes suitable for determination of glutathione is reported in this study. For this poly‐m‐aminophenol (PmAP), poly‐o‐aminophenol, and poly‐p‐aminophenol were electrochemically deposited from aqueous solution on the surface of glassy carbon (GC) electrode by potential cycling in the range of +0.2–+1.0 V. The modified GC electrodes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy, contact angle measurement and ellipsometry. It was found that poly‐m‐aminophenol modified GC electrode (PmAP/GC‐electrode) is most suitable for electroanalytical determination of glutathione. An electroanalytical system for the determination of glutathione based on the PmAP/GC‐electrode was developed. The analytical system was characterized by low limit of detection, good stability, high sensitivity and wide linear detection range.
Optimizing the Electrocatalytic Activity of Surface Confined Co Macrocyclics for the Electrooxidation of Thiocyanate at pH 4
Authors: Sancy Mamie , Pavez Jorge , Gulppi Miguel A. , de Mattos Ivanildo Luiz , Arratia‐Perez Ramiro , Linares‐Flores Cristian , Paez Maritza , Nyokong Tebello , Zagal José H.
Published: January 2011

We have studied the trends in catalytic activity of several Co macrocyclics confined on the surface graphite electrodes for the oxidation of thiocyanate. A plot of log i (at constant E) versus the formal potential of the catalyst gives a volcano correlation, indicating that the Co(II/I) redox potential needs to be tuned, in order to achieve maximum reactivity. Graphite electrodes modified with Co phthalocyanine at pH 4 exhibit linear amperometric response for thiocyanate concentration in the range 10−7 and 10−3 M. Theoretical calculations show that electrocatalytic activity (as log i at constant E) plotted versus the energy of the LUMO of the Co complex also gives a volcano correlation.
Development of a new rubber seismic isolator: ‘Ball Rubber Bearing (BRB)’
Authors: Ozkaya C. , Akyuz U. , Caner A. , Dicleli M. , Pınarbası S.
Published: January 2011

This paper presents an experimental research aimed at developing a new rubber‐based seismic isolator called ‘Ball Rubber Bearing (BRB)’. The BRB is composed of a conventional steel‐reinforced multi‐layered rubber bearing with its central hole filled with small diameter steel balls that are used to provide energy dissipation capacity through friction. A large set of BRBs with different geometrical and material properties are manufactured and tested under reversed cyclic horizontal loading at different vertical compressive load levels. Extensive test results indicate that steel balls do not only increase the energy dissipation capacity of the elastomeric bearing (EB), but also increase its horizontal and vertical stiffness. It is also observed that the energy dissipation capacity of a BRB does not degrade as the number of loading cycles increases. Copyright © 2011 John Wiley & Sons, Ltd.
Melting heat transfer in the stagnation‐point flow of an upper‐convected Maxwell (UCM) fluid past a stretching sheet
Authors: Hayat T. , Mustafa M. , Shehzad S. A. , Obaidat S.
Published: January 2011

The steady laminar boundary layer flow and heat transfer past a stretching sheet arre considered. Upper‐convected Maxwell (UCM) fluid is treated as a rheological model. The resulting nonlinear differential system is solved by homotopy analysis method (HAM). The influence of melting parameter (M), Prandtl number (Pr), Deborah number (β) and stretching ratio (A = a/c) on the velocity and temperature profiles is thoroughly examined. It is noticed that fields are effected appreciably with the variation of parameters. Furthermore, it is seen that the local Nusselt number is a decreasing function of melting parameter. Copyright © 2011 John Wiley & Sons, Ltd.
An efficient approach for calculation of pitching moment in nonlinear reduced frequency method at low Mach number transonic flows
Authors: Koopaee M. Kharati , Emdad H. , Alishahi M. M.
Published: January 2011

In this research, an efficient methodology for calculation of pitching moment coefficient at low Mach number transonic flows by using the perturbed nonlinear reduced frequency approach is presented. The proposed approach uses the perturbation technique in the nonlinear frequency domain (NLFD) method to estimate the solution at high harmonics. In this approach, the density and velocity fields at high harmonics are perturbed about those at low harmonics. Perturbing the density and velocity fields, the semi‐linear form of the governing equations is obtained. The resulting solution vector and spatial operator are then approximated by discrete form of Fourier transformation and governing equations are solved by using the pseudo‐spectral approach. Numerical results show that the proposed approach predicts good pitching moment coefficient at low Mach number transonic flows with up to 50% savings in computational time. Copyright © 2011 John Wiley & Sons, Ltd.
Efficient identification of uncertain parameters in a large‐scale tidal model of the European continental shelf by proper orthogonal decomposition
Authors: Altaf M. U. , Verlaan M. , Heemink A. W.
Published: January 2011

The adjoint method can be used to identify uncertain parameters in large‐scale shallow water flow models. This requires the implementation of the adjoint model, which is a large programming effort. The work presented here is inverse modeling based on model reduction using proper orthogonal decomposition (POD). An ensemble of forward model simulations is used to determine the approximation of the covariance matrix of the model variability and the dominant eigenvectors of this matrix are used to define a model subspace. An approximate linear reduced model is obtained by projecting the original model onto this reduced subspace. Compared with the classical variational method, the adjoint of the tangent linear model is replaced by the adjoint of a linear reduced forward model. The minimization process is carried out in reduced subspace and hence reduces the computational costs. In this study, the POD‐based calibration approach has been implemented for the estimation of the depth values and the bottom friction coefficient in a large‐scale shallow sea model of the entire European continental shelf with approximately 106 operational grid points. A number of calibration experiments is performed. The effectiveness of the algorithm is evaluated in terms of the accuracy of the final results as well as the computational costs required to produce these results. The results demonstrate that the POD calibration method with little computational effort and without the implementation of the adjoint code can be used to solve large‐scale inverse shallow water flow problems. Copyright © 2011 John Wiley & Sons, Ltd.
Mixed convection unsteady stagnation point flow over a stretching sheet with heat transfer in the presence of variable free stream
Authors: Hayat T. , Shehzad S. A. , Rafique Ansa , Malik M. Y.
Published: January 2011

An analysis is performed for the unsteady mixed convection flow of an incompressible viscous fluid about a stagnation point on a stretching sheet in the presence of a variable free stream. The equations of motion and energy are transformed into the ordinary differential equations by using similarity transformations. Homotopy analysis method is used for the solution of the governing problem. The results have been discussed by plots. The present values of the function are shown very close to the previous limiting solutions. Copyright © 2011 John Wiley & Sons, Ltd.
Option happiness and liquidity: Is the dynamics of the volatility smirk affected by relative option liquidity?
Authors: Nordén Lars , Xu Caihong
Published: January 2011

This study investigates the dynamic relationship between option happiness (the steepness of the volatility smirk) and relative index option liquidity. We find that, on a daily basis, option happiness is significantly dependent on the relative liquidity between option series with different moneyness. In particular, deterioration (improvement) in liquidity of an out‐of‐the‐money put option relative to a concurrent at‐the‐money call option would lead to higher (lower) option happiness. This relationship is robust to relative option liquidity measures based on bid–ask spreads, option price impacts, and option order book imbalances. The results also show a significant maturity effect in option happiness, consistent with the notion that options are “dying smiling.” © 2011 Wiley Periodicals, Inc. Jrl Fut Mark
Hepatocellular adenomas: Accuracy of magnetic resonance imaging and liver biopsy in subtype classification
Authors: Ronot Maxime , Bahrami Stephane , Calderaro Julien , Valla Dominique-Charles , Bedossa Pierre , Belghti Jacques , Vilgrain Valérie , Paradis Valérie
Published: January 2011

Hepatocellular adenomas (HCAs) are divided into genotype/phenotype subgroups associated with different evolutive profiles. Therefore, recognition of subtype is of clinical importance in patient management. Magnetic resonance imaging (MRI) is considered the most informative imaging modality and liver biopsy a key diagnostic tool whose role in HCA subtyping has never been extensively studied. The purpose of our study was to evaluate the diagnostic performance of MRI and liver biopsy with and without immunohistochemistry and to assess the interobserver agreement for MR classification in a consecutive series of resected HCAs. Forty-seven HCAs with preoperative MRI and biopsy were retrospectively included. MRI data were reviewed independently by two abdominal radiologists blind to the pathological results and classification. Subtyping of HCAs on liver biopsy was made blindly to clinical, biological, and imaging data and to final classification. Routine histological analysis was based on morphological criteria and immunohistochemistry was systematically performed when enough tissue was available. Final subtyping of HCA was based on the examination of the surgical specimen. Radiologists correctly classified HCAs in 85%. The interobserver kappa correlation coefficient was 0.86. Routine histological analysis led to 76.6% of correct classification and 81.6% when immunophenotypical characteristics were available. The additional value of immunophenotypical markers is best in HCAs containing steatosis. Agreement between MRI findings and routine histological analysis was observed in 74.5%, leading to a likelihood ratio of subtype diagnosis higher than 20.

Conclusion:

MRI and biopsy analysis are two efficient methods in subtyping HCAs and their association increases the diagnosis confidence. Interobserver variability in MRI criteria is very low. (HEPATOLOGY 2011;)
Transcription coactivator mediator subunit MED1 Is required for the development of fatty liver in the mouse
Authors: Bai Liang , Jia Yuzhi , Viswakarma Navin , Huang Jiansheng , Vluggens Aurore , Wolins Nathan E. , Jafari Nadereh , Rao Sambasiva M. , Borensztajn Jayme , Yang Gongshe , Reddy Janardan K.
Published: January 2011

Peroxisome proliferator-activated receptor-γ (PPARγ), a nuclear receptor, when overexpressed in liver stimulates the induction of adipocyte-specific and lipogenesis-related genes and causes hepatic steatosis. We report here that Mediator 1 (MED1; also known as PBP or TRAP220), a key subunit of the Mediator complex, is required for high-fat diet-induced hepatic steatosis as well as PPARγ-stimulated adipogenic hepatic steatosis. Mediator forms the bridge between transcriptional activators and RNA polymerase II. MED1 interacts with nuclear receptors such as PPARγ and other transcriptional activators. Liver-specific MED1 knockout (MED1δLiv) mice, when fed a high-fat (60% kcal fat) diet for up to 4 months failed to develop fatty liver. Similarly, MED1δLiv mice injected with adenovirus-PPARγ (Ad/PPARγ) by tail vein also did not develop fatty liver, whereas mice with MED1 (MED1fl/fl) fed a high-fat diet or injected with Ad/PPARγ developed severe hepatic steatosis. Gene expression profiling and northern blot analyses of Ad/PPARγ-injected mouse livers showed impaired induction in MED1δLiv mouse liver of adipogenic markers, such as aP2, adipsin, adiponectin, and lipid droplet-associated genes, including caveolin-1, CideA, S3-12, and others. These adipocyte-specific and lipogenesis-related genes are strongly induced in MED1fl/fl mouse liver in response to Ad/PPARγ. Re-expression of MED1 using adenovirally-driven MED1 (Ad/MED1) in MED1δLiv mouse liver restored PPARγ-stimulated hepatic adipogenic response. These studies also demonstrate that disruption of genes encoding other coactivators such as SRC-1, PRIC285, PRIP, and PIMT had no effect on hepatic adipogenesis induced by PPARγ overexpression.

Conclusion:

We conclude that transcription coactivator MED1 is required for high-fat diet-induced and PPARγ-stimulated fatty liver development, which suggests that MED1 may be considered a potential therapeutic target for hepatic steatosis. (HEPATOLOGY 2011;)
Human Hepatic Stem Cell and Maturational Liver Lineage Biology Δ
Authors: Turner Rachael , Lozoya Oswaldo , Wang Yunfang , Cardinale Vincenzo , Gaudio Eugenio , Alpini Gianfranco , Mendel Gemma , Wauthier Eliane , Barbier Claire , Alvaro Domenico , Reid Lola M.
Published: January 2011

Livers are comprised of maturational lineages of cells beginning extrahepatically in the hepato-pancreatic common duct near the duodenum and intrahepatically in zone 1 by the portal triads. The extrahepatic stem cell niches are the peribiliary glands deep within the walls of the bile ducts; those intrahepatically are the canals of Hering in postnatal livers and that derive from ductal plates in fetal livers. Intrahepatically, there are at least eight maturational lineage stages from the stem cells in zone 1 (periportal), through the midacinar region (zone 2), to the most mature cells and apoptotic cells found pericentrally in zone 3. Those found in the biliary tree are still being defined. Parenchymal cells are closely associated with lineages of mesenchymal cells, and their maturation is coordinated. Each lineage stage consists of parenchymal and mesenchymal cell partners distinguishable by their morphology, ploidy, antigens, biochemical traits, gene expression, and ability to divide. They are governed by changes in chromatin (e.g., methylation), gradients of paracrine signals (soluble factors and insoluble extracellular matrix components), mechanical forces, and feedback loop signals derived from late lineage cells. Feedback loop signals, secreted by late lineage stage cells into bile, flow back to the periportal area and regulate the stem cells and other early lineage stage cells in mechanisms dictating the size of the liver mass. Recognition of maturational lineage biology and its regulation by these multiple mechanisms offers new understandings of liver biology, pathologies, and strategies for regenerative medicine and treatment of liver cancers. (Hepatology 2011;)
Evidence for distinct pathways of hepcidin regulation by acute and chronic iron loading in mice
Authors: Ramos Emilio , Kautz Léon , Rodriguez Richard , Hansen Michael , Gabayan Victoria , Ginzburg Yelena , Roth Marie-Paule , Nemeth Elizabeta , Ganz Tomas
Published: January 2011

In response to iron loading, hepcidin synthesis is homeostatically increased to limit further absorption of dietary iron and its release from stores. Mutations in HFE, transferrin receptor 2 (Tfr2), hemojuvelin (HJV), or bone morphogenetic protein 6 (BMP6) prevent appropriate hepcidin response to iron, allowing increased absorption of dietary iron, and eventually iron overload. To understand the role each of these proteins plays in hepcidin regulation by iron, we analyzed hepcidin messenger RNA (mRNA) responsiveness to short and long-term iron challenge in iron-depleted

Hfe

,

Tfr2

,

Hjv

, and

Bmp6

mutant mice. After 1-day (acute) iron challenge,

Hfe-/-

mice showed a smaller hepcidin increase than their wild-type strain-matched controls,

Bmp6-/-

mice showed nearly no increase, and

Tfr2

and

Hjv

mutant mice showed no increase in hepcidin expression, indicating that all four proteins participate in hepcidin regulation by acute iron changes. After a 21-day (chronic) iron challenge,

Hfe

and

Tfr2

mutant mice increased hepcidin expression to nearly wild-type levels, but a blunted increase of hepcidin was seen in

Bmp6-/-

and

Hjv-/-

mice. BMP6, whose expression is also regulated by iron, may mediate hepcidin regulation by iron stores. None of the mutant strains (except Bmp6-/- mice) had impaired BMP6 mRNA response to chronic iron loading.

Conclusion:

TfR2, HJV, BMP6, and, to a lesser extent, HFE are required for the hepcidin response to acute iron loading, but are partially redundant for hepcidin regulation during chronic iron loading and are not involved in the regulation of BMP6 expression. Our findings support a model in which acute increases in holotransferrin concentrations transmitted through HFE, TfR2, and HJV augment BMP receptor sensitivity to BMPs. A distinct regulatory mechanism that senses hepatic iron may modulate hepcidin response to chronic iron loading. (HEPATOLOGY 2011;)
Suppression of innate immunity (natural killer cell/interferon-γ) in the advanced stages of liver fibrosis in mice
Authors: Jeong Won-Il , Park Ogyi , Suh Yang-Gun , Byun Jin-Seok , Park So-Young , Choi Earl , Kim Ja-Kyung , Ko Hyojin , Wang Hua , Miller Andrew M. , Gao Bin
Published: January 2011

Activation of innate immunity (natural killer [NK] cell/interferon-γ [IFN-γ]) has been shown to play an important role in antiviral and antitumor defenses as well as antifibrogenesis. However, little is known about the regulation of innate immunity during chronic liver injury. Here, we compared the functions of NK cells in early and advanced liver fibrosis induced by a 2-week or a 10-week carbon tetrachloride (CCl4) challenge, respectively. Injection of polyinosinic-polycytidylic acid (poly I:C) or IFN-γ induced NK cell activation and NK cell killing of hepatic stellate cells (HSCs) in the 2-week CCl4 model. Such activation was diminished in the 10-week CCl4 model. Consistent with these findings, the inhibitory effect of poly I:C and IFN-γ on liver fibrosis was markedly reduced in the 10-week versus the 2-week CCl4 model.

In vitro

coculture experiments demonstrated that 4-day cultured (early activated) HSCs induce NK cell activation via an NK group 2 member D/retinoic acid-induced early gene 1-dependent mechanism. Such activation was reduced when cocultured with 8-day cultured (intermediately activated) HSCs due to the production of transforming growth factor-β (TGF-β) by HSCs. Moreover, early activated HSCs were sensitive, whereas intermediately activated HSCs were resistant to IFN-γ-mediated inhibition of cell proliferation, likely due to elevated expression of suppressor of cytokine signaling 1 (SOCS1). Disruption of the SOCS1 gene restored the IFN-γ inhibition of cell proliferation in intermediately activated HSCs. Production of retinol metabolites by HSCs contributed to SOCS1 induction and subsequently inhibited IFN-γ signaling and functioning, whereas production of TGF-β by HSCs inhibited NK cell function and cytotoxicity against HSCs.

Conclusion:

The antifibrogenic effects of NK cell/IFN-γ are suppressed during advanced liver injury, which is likely due to increased production of TGF-β and expression of SOCS1 in intermediately activated HSCs. (HEPATOLOGY 2011;)
Correction of TRMM 3B43 monthly precipitation data over the mountainous areas of Peru during the period 1998–2007
Authors: Condom Thomas , Rau Pedro , Espinoza Jhan Carlo
Published: January 2011

In an attempt to estimate the spatial and temporal behaviour of rainfall over the mountainous areas of the Peruvian Andes, a new in situ monthly rainfall dataset has been collected (1998–2007) and compared with Tropical Rainfall Measuring Mission (TRMM) 3B43 monthly precipitation data for regions located above 3000 m. The reliability of the TRMM 3B43 data varies depending on the root mean squared error ratio (%RMSE) and correlation coefficient. Because of the discrepancy between the two datasets, the use of additive and multiplicative correction models is proposed for the TRMM 3B43 data. In the Peruvian mountain ranges, these correction models better approximate TRMM rainfall monthly values, as already verified for annual values. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of cumulative stress on fish health near freshwater outlet sluices into the sea: A case study (1988–2005) with evidence for a contributing role of chemical contaminants
Authors: Vethaak A Dick , Jol Johan G , Martínez-Gómez Concepción
Published: January 2011

Epizootic skin diseases in euryhaline flounder (Platichthys flesus) in the Dutch Wadden Sea were first reported in 1988. Particularly high prevalences of skin ulcers (up to one-third of individual fish being affected) were encountered in the vicinity of sluices draining freshwater from IJsselmeer Lake, in contrast with much lower levels in the freshwater bodies behind the sluices and open sea areas (<2%). It was proposed that salinity stress, high bacterial loads, nutritional deficiencies, and obstruction to fish migration by the sluices could all be involved in disease causation. Results of follow-up surveys at these outlet sluices from 1994 to 2005 further substantiate our preliminary findings. The follow-up data also show a general reduction in disease and improved condition factor during this period, which can be explained by improved habitat conditions for the flounder, partly due to effective sluice gate management. Furthermore, statistical correlations (p < 0.05) were demonstrated between flounder ulcer occurrence and chemical contaminant concentrations in liver (Hg, Cd, Cu, Zn) and bile (the metabolite 1-OH pyrene as an indicator of chronic polycyclic aromatic hydrocarbon exposure), and histological liver lesions generally indicative of contaminant exposure (hydropic vacuolization of biliary duct epithelial cells). The findings suggest that a combination of osmotic and contaminant-induced stress also contributed to the observed disease patterns. Integr Environ Assess Manag 2011;7:445–458. © 2011 SETAC
Spatially explicit ecological exposure models: A rationale for and path toward their increased acceptance and use
Authors: Wickwire Theodore , Johnson Mark S , Hope Bruce K , Greenberg Marc S
Published: January 2011

Spatially explicit wildlife exposure models have been developed to integrate chemical concentrations dispersed in space and time, heterogeneous habitats of varying qualities, and foraging behaviors of wildlife to give more realistic wildlife exposure estimates for ecological risk assessments. These models not only improve the realism of wildlife exposure estimates, but also increase the efficiency of remedial planning. However, despite being widely available, these models are rarely used in baseline (definitive) ecological risk assessments. A lack of precedent for their use, misperceptions about models in general and spatial models in particular, non-specific or no enabling regulations, poor communication, and uncertainties regarding inputs are all impediments to greater use of such models. An expert workshop was convened as part of an Environmental Security Technology Certification Program Project to evaluate current applications for spatially explicit models and consider ways such models could bring increased realism to ecological exposure assessments. Specific actions (e.g., greater accessibility and innovation in model design, increased communication with and training opportunities for decision makers and regulators, explicit consideration during assessment planning and problem formulation) were discussed as mechanisms to increase the use of these valuable and innovative modeling tools. The intent of this workshop synopsis is to highlight for the ecological risk assessment community both the value and availability of a wide range of spatial models and to recommend specific actions that may help to increase their acceptance and use by ecological risk assessment practitioners. Integr Environ Assess Manag 2011;7:158–168. © 2011 SETAC
Babies open our minds to their minds: How “listening” to infant signs complements and extends our knowledge of infants and their development
Authors: Vallotton Claire
Published: January 2011

Preverbal children are capable of explicitly communicating their own desires, emotions, and thoughts through infant signs (i.e., symbolic gestures) that they have invented or learned from caregivers. In this article, I describe seven lines of child development research and show how attending to infants' use of signs can complement and extend this knowledge of development for both scientists and caregivers. The areas of developmental research include object permanence, categorization, shared meaning, mental state understanding and absent reference, emotion knowledge, identity, and self‐regulation. I present qualitative data on infants' signing gathered through videos of caregiver–child interaction, student caregivers' systematic participant observations, my own observations in an infant classroom, and volunteered sign stories from parents who use signs with their infants. I also present quotes from interviews with parents and caregivers of signing children to show how infants' signing affects adults' perceptions of and feelings toward children. With infant signs, infants reveal their thoughts, feelings, interests, and personalities in their own contexts through everyday interactions. By “listening” to infant signs, parents, practitioners, and scientists gain insight into individual infants and respect for the often underestimated capacities of preverbal children.
Artefact reduction for cell migration visualization using spectral domain optical coherence tomography
Authors: Hofer Bernd , Povazˇay Boris , Hermann Boris , Rey Sara M. , Kajić Vedran , Tumlinson Alexandre , Powell Kate , Matz Gerald , Drexler Wolfgang
Published: January 2011

Visualization of cell migration during chemotaxis using spectral domain optical coherence tomography (OCT) requires non‐standard processing techniques. Stripe artefacts and camera noise floor present in OCT data prevent detailed computer‐assisted reconstruction and quantification of cell locomotion. Furthermore, imaging artefacts lead to unreliable results in automated texture based cell analysis.

Here we characterize three pronounced artefacts that become visible when imaging sample structures with high dynamic range, e.g. cultured cells: (i) time‐varying fixed‐pattern noise; (ii) stripe artefacts generated by background estimation using tomogram averaging; (iii) image modulations due to spectral shaping. We evaluate techniques to minimize the above mentioned artefacts using an 800 nm optical coherence microscope. Effect of artefact reduction is shown exemplarily on two cell cultures, i.e. Dictyostelium on nitrocellulose substrate, and retinal ganglion cells (RGC‐5) cultured on a glass coverslip. Retinal imaging also profits from the proposed processing techniques. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cochlear implantation in a patient with paget's disease
Authors: Wolfovitz Amit , Shihada Rabia , Shpak Talma , Braun Jacob , Luntz Michal
Published: January 2011

Hearing loss in Paget's disease, a metabolic bone disease, has been reported in as many as 60% of cases, and is presumably related to changes in mineral density of the otic capsule. We describe a 59‐year‐old man with Paget's disease who had severe to profound hearing loss and was referred to us for cochlear implantation. Preoperative evaluation revealed poor communication skills despite significant residual hearing, raising concerns about postimplantation outcome. Nevertheless, implantation was successful. As our literature search yielded only one report of cochlear implantation in Paget's disease, we record our clinical experience and discuss the hearing rehabilitation dilemmas in this case.
Altered expression of middle and inner ear cytokines in mouse otitis media
Authors: MacArthur Carol J. , Pillers De‐Ann M. , Pang Jiaqing , Kempton J. Beth , Trune Dennis R.
Published: January 2011

Objectives/Hypothesis:

The inner ear is at risk for sensorineural hearing loss in both acute and chronic otitis media (OM), but the mechanisms underlying sensorineural hearing loss are unknown. Previous gene expression array studies have shown that cytokine genes might be upregulated in the cochleas of mice with acute and chronic OM. This finding implies that the inner ear could manifest a direct inflammatory response to OM that may cause sensorineural damage. Therefore, to better understand inner ear cytokine gene expression during OM, quantitative real‐time polymerase chain reaction and immunohistochemistry were used in mouse models to evaluate middle and inner ear inflammatory and remodeling cytokines.

Study Design:

Basic science experiment.

Methods:

An acute OM model was created in Balb/c mice by a transtympanic injection of Streptococcus
pneumoniae in one ear; the other ear was used as a control. C3H/HeJ mice were screened for unilateral chronic OM, with the noninfected ear serving as a control.

Results:

Both acute and chronic OM caused both the middle ear and inner tissues in these two mouse models to overexpress numerous cytokine genes related to tissue remodeling (tumor necrosis factor‐α, bone morphogenetic proteins, fibroblast growth factors) and angiogenesis (vascular endothelial growth factor), as well as inflammatory cell proliferation (interleukin [IL]‐1α,β, IL‐2, IL‐6). Immunohistochemistry confirmed that both the middle ear and inner ear tissues expressed these cytokines.

Conclusions:

Cochlear tissues are capable of expressing cytokine mRNA that contributes to the inflammation and remodeling that occur in association with middle ear disease. This provides a potential molecular basis for the transient and permanent sensorineural hearing loss often reported with acute and chronic OM.
Endoscopic approach to the orbital apex and periorbital skull base
Authors: Murchison Ann P. , Rosen Marc R. , Evans James J. , Bilyk Jurij R.
Published: January 2011

Objectives/Hypothesis:

To review cases of endoscopic orbital apex and periorbital skull base surgery and stratify the pathology and lesion location. Variations in surgical technique and the outcomes are reviewed. We report the results of all cases of endoscopic orbital apex surgery over a 40‐month period. Eighteen cases with a variety of pathology, location in the orbital apex, and surgical technique are reviewed.

Study Design:

Retrospective chart review.

Methods:

All cases of endoscopic orbital apex and periorbital skull base surgery over a 40‐month period were reviewed. Lesion location, surgical approach, pathology, and postoperative complications are summarized. The details of the technique as well as limitations and advantages of this approach are summarized.

Results:

Eighteen patients who underwent endoscopic orbital apex surgery were identified. Eleven (61%) of the patients were men, and the average age was 51 years. The majority of lesions, 12 (67%), were located in the medial orbit and/or optic canal, two (11%) in the cavernous sinus and/or superior orbital fissure, and four (22%) in the inferior orbit and/or pterygopalatine fossa. The etiologies were diverse, including benign (44%), malignant (28%), infectious (11%), and inflammatory (17%). The majority of cases, 67%, were approached by the transnasal endoscopic technique followed by 28% with a combined transnasal and transcaruncular approach, and 6% by the sublabial approach. Complications occurred in 22% of cases.

Conclusions:

Conventional orbitotomy techniques and craniotomy are frequently used to access lesions in the orbital apex. The more recently described endoscopic technique with intraoperative image guidance can provide access to a subset orbital apical and periorbital skull base lesions. In carefully selected cases, this technique provides excellent visualization and access to the orbital apex and avoids larger craniofacial surgeries. Laryngoscope, 2011
Submucosal nerve hypertrophy in congenital laryngomalacia
Authors: Munson Patrick D. , Saad Ali G. , El‐Jamal Siraj M. , Dai Yuemeng , Bower Charles M. , Richter Gresham T.
Published: January 2011

Objectives/Hypothesis:

To determine the neuropathologic findings in tissue obtained from children with laryngomalacia at a tertiary‐care pediatric hospital.

Study Design:

Retrospective review of consecutive cohort compared with a control group.

Methods:

We reviewed supra‐arytenoid pathology specimens from 43 children with severe laryngomalacia and 13 age‐matched pediatric autopsy controls. Histopathologic comparison was made of nerve hypertrophy (including nerve perimeter and surface area) among experimental and control pathologic specimens.

Results:

There exists a statistically significant increase in nerve perimeter (P = .001) and nerve surface area (P = .02) in supra‐arytenoid specimens in patients with severe laryngomalacia compared with age‐matched autopsy supra‐arytenoid tissue.

Conclusions:

The pathologic finding of nerve hypertrophy in children with laryngomalacia provides new evidence to support neurologic dysfunction as the etiologic theory of laryngomalacia. Laryngoscope, 2011
Diagnosis and treatment of 32 cases with aortoesophageal fistula due to esophageal foreign body
Authors: Zhang Xiaoli , Liu Jiajia , Li Jingjia , Hu Jianguo , Yu Fenglei , Li Shunnong , Yang Xinming
Published: January 2011

Objectives/Hypothesis:

Aortoesophageal fistula is a rare but life‐threatening complication of foreign body ingestion. In spite of several strategies for treatment, there is little consensus regarding the optimal management of the entity. In this article, we present our experience in the diagnosis and treatment of patients with aortoesophageal fistula.

Study Design:

Retrospective study.

Methods:

A total of 3,209 admissions due to esophageal foreign body impaction were recorded in Second Xiangya Hospital between 1963 and 2010. Of these, 32 cases were complicated with aortoesophageal fistula. In these 32 patients, 19 were treated by open surgery and 13 were managed with nonsurgical measures. We compared different treatments of the patients and their clinical outcomes.

Results:

Foreign body and aortoesophageal fistula were found in all of these 32 cases in imaging examination and/or surgery. Three patients were completely cured and 16 patients died of fatal hemorrhage from the group of patients with surgical management. All 13 nonsurgically treated cases died.

Conclusions:

Early diagnosis and an aggressive surgical treatment without delay is the only form of effective therapy for the condition of aortoesophageal fistula. Imaging examination is helpful in diagnosis. In particular, three‐dimensional computerized tomography is a safe, simple, and noninvasive examination method that has high sensitivity and specificity for the early diagnosis of aortoesophageal fistula.
Corrosion of stainless steels in simulated diesel exhaust environment with urea
Authors: Nockert J. , Nyborg L. , Norell M.
Published: January 2011

Laboratory exposures have been performed simulating a selective catalytic reduction (SCR) system with urea injection for NOx reduction in diesel exhaust after‐treatment. The corrosion behaviour of three ferritic and one austenitic stainless steel was examined using X‐ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Continuous exposure to condensate did not cause any corrosion. Results show that cyclic interaction between high temperature and condensation aggravates the corrosion compared to isothermal exposure at 450 °C. All ferritic alloys exhibited more or less the same behaviour, while the austenitic steel performed better. In fact, the presence of urea decreased the corrosion compared to the environment without urea. The cyclic samples exposed with urea displayed iron sulphate on the surface. The sulphate appeared to decrease the oxide thickness. A sulphur enrichment in the form of sulphide also occurred in the inner chromium‐rich oxides of all cyclically exposed samples, both with and without urea. Thus, sulphidation is presumed to be involved in the corrosion process.
Experiences with high temperature corrosion at straw‐firing power plants in Denmark
Authors: Montgomery M. , Jensen S. A. , Borg U. , Biede O. , Vilhelmsen T.
Published: January 2011

By the end of 2009, there will be eight biomass and five biomass co‐firing plants in Denmark. Due to the steep increase of corrosion rate with respect to temperature in biomass plants, it is not viable to have similar steam data as fossil fuel plants. Thus for the newer plants, Maribo Sakskøbing, Avedøre 2 biomass boiler, Fyn 8 and Amager 1 (Fyn 8 and Amager 1 are under commissioning), the steam temperature of the final superheaters are approximately 540 °C and the steel type used is an 18–10 stainless steel, (TP347H). However there is still a need to monitor corrosion rates, and to collate data to enable better lifetime prediction of vulnerable components in straw‐firing plants since the corrosion rates are so much faster than in coal firing plants. Therefore, there are continued investigations in recently commissioned plants with test tubes installed into actual superheaters. In addition temperature is measured on the specific tube loops where there are test tube sections. Thus a corrosion rate can be coupled to a temperature histogram. This is important since although a superheater has a defined steam outlet temperature, there is variation in the tube bundle due to variations of heat flux from the flue gas. This paper will describe the corrosion investigations for tube sections removed from Maribo Sakskøbing and Avedøre 2 biomass boiler which have been exposed for up to 30 000 h. In addition to monitoring the corrosion rates of actual components, there is a need to measure corrosion rates at higher temperatures to assess if there is a possibility to increase the outlet temperature of the plant, thus making the plant more cost effective. For this purpose Avedøre 2 biomass boiler has a test superheater loop fabricated in TP347H FG (the same material as the final superheaters). Some results from this test superheater will also be described. Effects of flue gas temperature and flue gas direction on corrosion rates are also discussed.
Temperature and gas composition dependence of internal oxidation kinetics of an Fe10%Cr alloy in water vapour containing environments
Authors: Zurek J. , Meier G. H. , Wessel E. , Singheiser L. , Quadakkers W. J.
Published: January 2011

Recently it was proposed, that the hampered formation of external protective chromia scales on FeCr‐alloys in water vapour containing, low‐pO2 gases is correlated with enhanced internal oxidation of chromium. In the present study the internal oxidation kinetics of Fe10Cr (in mass%) during isothermal oxidation in ArH2H2O mixtures at temperatures in the range 800–1050 °C has been investigated. It was found that the tendency for Cr to become internally oxidized decreased with decreasing temperature. At the higher test temperatures the internal oxide precipitates consisted of Fe/Cr‐spinel. With decreasing temperature the precipitates near the oxidation front gradually exhibited increasing amounts of chromia. At 900 °C the oxidation morphology in the ArH2 base gas mixture changed from exclusive internal oxidation of Cr at a water vapour content of 2% towards a combined internal Cr oxidation and external Fe‐oxide formation at higher water vapour partial pressures.