bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculating Energy Flux in Internal Solitary Waves with an Application to Reflectance
Authors: Lamb Kevin G. , Nguyen Van T. 
Published: August 2008

Abstract
The energetics of internal solitary waves (ISWs) in continuous, quasi-two-layer stratifications are explored using fully nonlinear, nonhydrostatic numerical simulations. The kinetic energy of an internal solitary wave is always greater than the available potential energy, by as much as 30% for the stratifications considered. Because of different spatial distributions of the kinetic and available potential energy densities, however, the fluxes are quite different. The available potential energy flux is found to always exceed the kinetic energy flux, by as much as a factor of 5. The sizes of the various fluxes in the wave pseudoenergy (kinetic plus available potential energy) equation are compared, showing that, while the linear flux term (velocity–pressure perturbation) dominates the fluxes, the fluxes of available potential and kinetic energy are significant for large ISWs. Past work on estimating the reflectance (ratio of reflected to incident pseudoenergy flux) associated with internal solitary waves incident on a linearly sloping bottom in laboratory experiments and numerical simulations has incorrectly assumed that the available potential energy flux was equal to the kinetic energy flux. Hence, the sensitivity of reflectance estimates to the way the flux is calculated is investigated. For these low Reynolds number situations, it is found that a correct account of the available potential energy flux reduces the reflectance by as much as 0.1 when the pycnocline is close to the surface.
Nonlinear Advection Algorithms Applied to Interrelated Tracers: Errors and Implications for Modeling Aerosol–Cloud Interactions
Authors: Ovtchinnikov Mikhail , Easter Richard C. 
Published: August 2008

Abstract
Monotonicity constraints and gradient-preserving flux corrections employed by many advection algorithms used in atmospheric models make these algorithms nonlinear. Consequently, any relations among model variables transported separately are not necessarily preserved in such models. These errors cannot be revealed by traditional algorithm testing based on advection of a single tracer. New types of tests are developed and conducted to evaluate the monotonicity of a sum of several number mixing ratios advected independently of each other—as is the case, for example, in models using bin or sectional representations of aerosol or cloud particle size distributions. The tests show that when three tracers with an initially constant sum are advected separately in one-dimensional constant velocity flow, local errors in their sum can be on the order of 10%. When cloudlike interactions are allowed among the tracers in the idealized “cloud base” test, errors in the sum of three mixing ratios can reach 30%. Several approaches to eliminate the error are suggested, all based on advecting the sum as a separate variable and then using it to normalize the sum of the individual tracers’ mixing ratios or fluxes. A simple scalar normalization ensures the monotonicity of the total number mixing ratio and positive definiteness of the variables, but the monotonicity of individual tracers is no longer maintained. More involved flux normalization procedures are developed for the flux-based advection algorithms to maintain the monotonicity for individual scalars and their sum.
Mononuclear myeloid-derived “suppressor” cells express RAE-1 and activate natural killer cells
Authors: Nausch Norman , Galani Ioanna E. , Schlecker Eva , Cerwenka Adelheid 
Published: August 2008

AbstractMyeloid-derived suppressor cells (MDSCs) accumulate in cancer patients and tumor-bearing mice and potently suppress T-cell activation. In this study, we investigated whether MDSCs regu-late natural killer (NK)–cell function. We discovered that mononuclear Gr-1+CD11b+F4/80+ MDSCs isolated from RMA-S tumor-bearing mice do not suppress, but activate NK cells to produce high amounts of IFN-γ. Gr-1+CD11b+F4/80+ MDSCs isolated from tumor-bearing mice, but not myeloid cells from naive mice, expressed the ligand for the activating receptor NKG2D, RAE-1. NK-cell activation by MDSCs depended partially on the interaction of NKG2D on NK cells with RAE-1 on MDSCs. NK cells eliminated Gr-1+CD11b+F4/80+ MDSCs in vitro and upon adoptive transfer in vivo. Finally, depletion of Gr-1+ cells that comprise MDSCs confirmed their protective role against the NK-sensitive RMA-S lymphoma in vivo. Our study reveals that MDSCs do not suppress all aspects of antitumor immune responses and defines a novel, unexpected activating role of MDSCs on NK cells. Thus, our results have great impact on the design of immune therapies against cancer aiming at the manipulation of MDSCs.
Effect of roflumilast on inflammatory cells in the lungs of cigarette smoke-exposed mice
Authors: Martorana Piero A , Lunghi Benedetta , Lucattelli Monica , De Cunto Giovanna , Beume Rolf , Lungarella Giuseppe 
Published: August 2008

Abstract

Background
We reported that roflumilast, a phosphodiesterase 4 inhibitor, given orally at 5 mg/kg to mice prevented the development of emphysema in a chronic model of cigarette smoke exposure, while at 1 mg/kg was ineffective. Here we investigated the effects of roflumilast on the volume density (VV) of the inflammatory cells present in the lungs after chronic cigarette smoke exposure.

Methods
Slides were obtained from blocks of the previous study and VV was assessed immunohistochemically and by point counting using a grid with 48 points, a 20× objective and a computer screen for a final magnification of 580×. Neutrophils were marked with myeloperoxidase antibody, macrophages with Mac-3, dendritic cells with fascin, B-lymphocytes with B220, CD4+ T-cells with CD4+ antibody, and CD8+T-cells with CD8-α. The significance of the differences was calculated using one-way analysis of variance.

Results
Chronic smoke exposure increased neutrophil VV by 97%, macrophage by 107%, dendritic cell by 217%, B-lymphocyte by 436%, CD4+ by 524%, and CD8+ by 417%. The higher dose of roflumilast prevented the increase in neutrophil VV by 78%, macrophage by 82%, dendritic cell by 48%, B-lymphocyte by 100%, CD4+ by 98% and CD8+ VV by 88%. The lower dose of roflumilast did not prevent the increase in neutrophil, macrophage and B-cell VV but prevented dendritic cells by 42%, CD4+ by 55%, and CD8+ by 91%.

Conclusion
These results indicate (i) chronic exposure to cigarette smoke in mice results in a significant recruitment into the lung of inflammatory cells of both the innate and adaptive immune system; (ii) roflumilast at the higher dose exerts a protective effect against the recruitment of all these cells and at the lower dose against the recruitment of dendritic cells and T-lymphocytes; (iii) these findings underline the role of innate immunity in the development of pulmonary emphysema and (iiii) support previous results indicating that the inflammatory cells of the adaptive immune system do not play a central role in the development of cigarette smoke induced emphysema in mice.
Role of neutrophil proteinase 3 and mast cell chymase in chemerin proteolytic regulation
Authors: Guillabert Aude , Wittamer Valérie , Bondue Benjamin , Godot Véronique , Imbault Virginie , Parmentier Marc , Communi David 
Published: August 2008

AbstractChemerin is a potent chemotactic factor that was identified recently as the ligand of ChemR23, a G protein-coupled receptor expressed by mononuclear phagocytes, dendritic cells (DCs), and NK cells. Chemerin is synthesized as a secreted precursor, prochemerin, which is poorly active on ChemR23. However, prochemerin can be converted rapidly into a full ChemR23 agonist by proteolytic removal of a carboxy-terminal peptide. This maturation step is mediated by the neutrophil-derived serine proteases elastase and cathepsin G. In the present work, we have investigated proteolytic events that negatively control chemerin activity. We demonstrate here that neutrophil-derived proteinase 3 (PR3) and mast cell (MC) chymase are involved in the generation of specific chemerin variants, which are inactive, as they do not induce calcium release or DC chemotaxis. Mass spectrometry analysis showed that PR3 specifically converts prochemerin into a chemerin form, lacking the last eight carboxy-terminal amino acids, and is inactive on ChemR23. Whereas PR3 had no effect on bioactive chemerin, MC chymase was shown to abolish chemerin activity by the removal of additional amino acids from its C-terminus. This effect was shown to be specific to bioactive chemerin (chemerin-157 and to a lesser extent, chemerin-156), as MC chymase does not use prochemerin as a substrate. These mechanisms, leading to the production of inactive variants of chemerin, starting from the precursor or the active variants, highlight the complex interplay of proteases regulating the bioactivity of this novel mediator during early innate immune responses.
A risk‐neutral default for chemical risk management
Authors: Hansson Sven Ove , Rudén Christina 
Published: August 2008

AbstractIn many risk management decisions concerning industrial chemicals, including decisions on classification and labeling, lack of toxicity data is interpreted as (or has the same implications as) absence of toxicity. In other words, if the toxicity of a chemical is unknown, it is treated as having no or low toxicity. This practice is difficult to defend from a decision‐theoretical point of view. We apply standard decision theory to toxicity data and investigate an alternative approach in which substances with unknown properties are treated as if they had the average toxicity among tested substances in the group to which they belong. An index of acute toxicity is proposed and then used to define a risk‐neutral hazard default that can be applied to industrial chemicals for which no specific information on acute toxicity is available. It is proposed that such a risk‐neutral approach is preferable to the current practice of treating substances with unknown acute toxicity in the same manner as substances that can reasonably be assumed to have no such harmful properties. The risk‐neutral approach could be generalized to other toxicological endpoints. Am. J. Ind. Med. 51:964–967, 2008. © 2008 Wiley‐Liss, Inc.
Delay‐dependant robust stability and stabilization conditions for a class of Lur'e singular time‐delay systems
Authors: Lu Renquan , Dai Xiaozhen , Su Hongye , Chu Jian , Xue Anke 
Published: August 2008

AbstractThe problem of the delay‐dependant robust stability and stabilization is dealt with for a class of Lur'e singular system with state time‐delays in this paper. The new concept of generalized robust quadratic stability and generalized robust quadratic stabilization is presented. Furthermore, the sufficient condition of the robust stability and stabilization is also proposed based on linear matrix inequalities. The synthesis problem addressed is to design a memoryless state feedback control law such that the resulting closed‐loop system is regular, impulse free and asymptotically stable for all admissible uncertainties. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Intramolecular π‐Stacking in Isostructural Conformational Probes Depends Strongly on Charge Separation, a Proton NMR Study
Authors: Poudel Pramod Prasad , Chen Jing , Cammers Arthur 
Published: August 2008

AbstractOur solution state conformational methods used previously to study a dicationic molecular template for intramolecular aromatic association were applied to a neutral hydrocarbon analogue to probe the effect of charge on conformation. Conformational analysis of the hydrocarbon revealed modest solvent dependence in largely unfolded molecules. Conformations found in the solid state were unfolded also corroborating the findings of the solution‐state study. This study also adds solid‐state evidence for three competing solution‐state conformers previously predicted by calculations. In the absence of charge, the molecular template does not favor intramolecular association of aromatic substituents. These results agree with the chemical literature and previous reports of neutral hydrocarbon intramolecular association in the solution state.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
PKC‐mediated secretion of death factors in LNCaP prostate cancer cells is regulated by androgens
Authors: Xiao Liqing , Gonzalez‐Guerrico Anatilde , Kazanietz Marcelo G. 
Published: August 2008

AbstractActivation of PKCδ in androgen‐dependent LNCaP prostate cancer cells leads to apoptosis via the activation of p38 MAPK and JNK cascades. We have recently shown that treatment of LNCaP cells with phorbol 12‐myristate 13‐acetate (PMA) leads to a PKCδ‐mediated autocrine release of death factors, including the cytokines TNFα and TRAIL, and that conditioned medium (CM) collected from PMA‐treated LNCaP cells promotes the activation of the extrinsic apoptotic cascade. Interfering with this autocrine loop either at the level of factor release or death receptor activation/signaling markedly impaired the PMA apoptotic response. In the present study we show that this PKCδ‐dependent autocrine mechanism is greatly influenced by androgens. Indeed, upon androgen depletion, which down‐regulates PKCδ expression, TNFα and TRAIL mRNA induction and release by PMA are significantly diminished, resulting in a reduced apoptogenic activity of the CM and an impaired ability of the CM to activate p38 MAPK and JNK. These effects can be rescued by addition of the synthetic androgen R1881. Furthermore, RNAi depletion of the androgen‐receptor (AR) from LNCaP cells equally impaired PMA responses, suggesting that PKC‐mediated induction of death factor secretion and apoptosis in LNCaP prostate cancer cells are highly sensitive to hormonal control. © 2008 Wiley‐Liss, Inc.
Coulomb effects in single‐walled carbon nanotubes
Authors: Malić Ermin , Hirtschulz Matthias , Milde Frank , Richter Marten , Maultzsch Janina , Reich Stephanie , Knorr Andreas 
Published: August 2008

AbstractWe present microscopic calculations of the excitonic absorption coefficient for single‐wall carbon nanotubes. Our approach combines the density matrix formalism including the Coulomb and electron‐light interaction with the tight‐binding approximation. It allows the investigation of excitons in carbon nanotubes of arbitrary chiral index over a wide range of energy. We take all intra‐ and intersubband contributions into account and study the behavior of the Coulomb matrix elements for all relevant processes. The Coulomb interaction is found to decrease strongly with increasing momentum transfer perpendicular to the nanotube axis. Furthermore, we show that the band gap renormalization arising from the electronelectron interaction leads to a partial lifting of degeneracy in the spectra of zig‐zag tubes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and selected properties of a composite of the C60‐Pd conducting polymer and single‐wall carbon nanotubes
Authors: Pieta Piotr , Grodzka Emilia , Winkler Krzysztof , Venukadasula Ganesh M. , D'Souza Francis , Kutner Wlodzimierz 
Published: August 2008

AbstractA thin film of a new composite consisting of the redox conductive fullerene‐palladium polymer (C60‐Pd) and single‐wall carbon nanotubes, non‐covalently functionalized with 1‐pyrenebutiric acid (pyr‐SWCNTs), was electrochemically prepared in the acetonitrile: toluene (1: 4, v: v) solution containing C60, pyr‐SWCNTs, and palladium acetate, Pd(ac)2, under multi‐scan cyclic voltammetry (cv) conditions. A tetra(n‐butyl)ammonium salt, vis. 0.1 M (TBA)ClO4 or (TBA)PF6, was used as the supporting electrolyte. Electrochemical and visco‐elastic properties of the composite film were investigated by simultaneous cv and piezoelectric microgravimetry (pm) measurements. The Raman spectra indicated that pyr‐SWCNTs were incorporated in the film during preparation of the composite by electropolymerization. Mass of the deposited composite film was determined by pm using an electrochemical quartz crystal microbalance (EQCM). The EQCM also allowed us for simultaneous recording, in different potential ranges, the current, resonant frequency changes, and dynamic resistance changes vs. potential, of a quartz crystal resonator with its electrode coated by the composite film. The performed EQCM experiments revealed that both films were electrochemically active at potentials more negative than ca. –0.5 V. However, the presence of pyr‐SWCNTs in the film increased the electrode capacitance, as manifested by the increase of both the cv cathodic and anodic current. Moreover, the presence of pyr‐SWCNTs in the C60‐Pd polymer improved its visco‐elastic properties for the potentials more negative than –0.9 V vs. Ag/AgCl by making the C60‐Pd/pyr‐SWCNTs film more rigid than the pristine C60‐Pd film. From the highest slopes of the rising portions of the cathodic currents in the range ca. –0.4 to –0.6 V the redox conductivity values were determined. This conductivity for the C60‐Pd/pyr‐SWCNTs composite film was higher than that for the genuine C60‐Pd film. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Spin Gap Transition around 180 K Observed in a New Molecular Magnet based on the [Ni(mnt)2]– Monoanion and Substituted Benzylpyridinium
Authors: Zuo Hongrong , Huang Qian , Hou Yong , Ni Chunlin , Hu Xuelei 
Published: August 2008

AbstractA new molecular magnet, [NO2BrBzPyCH3][Ni(mnt)2] (1) ([NO2BrBzPyCH3]+ = 1‐(2′‐bromo‐4′‐nitrobenzyl)‐2‐methylpyridinium, and mnt2– = maleonitriledithiolate), has been prepared and characterized by single crystal X‐ray diffraction and magnetic measurements. The Ni(III) ions of 1 form a quasi‐one‐dimensional alternating zig‐zag magnetic chain within a Ni(mnt)2– column by intermolecular Ni···S, Ni···Ni or π···π interactions, and the [NO2BrBzPyCH3]+ cations stack into a column via weak Br···O interaction, p···π stacking interactions and C‐H···O hydrogen bonds between the cations. Magnetic susceptibility measurements in the temperature range 1.8‐300 K show that 1 exhibits a spin‐gap transition around 180 K, and an antiferromagnetic interaction in the high‐temperature phase (HT) and spin gap behavior in the low‐temperature phase (LT). The transition for 1 is a second‐order phase transition as determined by DSC analyses.
Electrochemical and Chemical Syntheses of Trifluoromethylating Reagents and Trifluoromethyl Substituted Compounds
Authors: Grobe Joseph , Hegge Joachim 
Published: August 2008

AbstractThe electroreduction of the halofluoromethanes CF3Br, CF2Br2 and CF2BrCl has been studied in high‐pressure stainless steel autoclaves at different cathodes [Pt, steel (V2A, V4A), glassy carbon (GC)] and in various solvent‐supporting electrolyte systems (SSE), e.g. DMF/[Bu4N]Br, NMP/[Bu4N]BF4 etc. The reduction potentials for CF3Br increase from Pt (–1.6 V) < V2A (–1.8 V) < GC (–2.1 V) and are lower for CF2Br2 and CF2BrCl suggesting a reductive cleavage of C‐X bonds as the first step. CF2Br2 and CF2BrCl show a two‐step reduction in accord with the C–X bond energies (C–F > C–Cl > C–Br) and the “Perfluoro‐effect”. The electrolysis of CF3Br in different SSE‐systems with sacrificial zinc or cadmium anodes has been reinvestigated with our experimental set‐up to elucidate the influence of the experimental conditions on the type and ratio of the products. The observed products CF3MBr·42L and (CF3)2M·42L (M = Zn, Cd; L = DMF or AN) are the same as in the previous investigations, but are obtained in different ratios, as a rule caused by a parallel chemical corrosion of the respective anodes. By using aluminium as sacrificial anode no CF3Al compounds are formed. The CF3 species generated by electroreduction of CF3Br react with the solvents via hydrogen abstraction and formation of CF3H. The current yield with respect to the dissolution of the Al anode reaches 120 % indicating a considerable chemical corrosion in addition to the anodic oxidation. This result enabled a one‐pot trifluoromethylation reaction of NMP as organic carbonyl substrate and solvent with CF3Br and aluminium powder (ratio 3 : 2) at higher temperatures (> 70 °C). The complete reaction of CF3Br to give CF3H and 1‐methyl‐2‐trifluoromethyl‐4,5‐dihydropyrrol allowed the isolation of the latter by vacuum condensation and distillation in 45 % yield, rel. to the CF3Br used. Gallium and indium were also applied as sacrificial anodes in combination with CF3Br as substrate. In both cases, anodic current yields of about 280 % indicated an extreme chemical corrosion together with cathodic metal depositions corresponding to the cathodic current yield. These deposits – in contrast to those of Zn and Cd – do not react with CF3Br in Grignard‐type conversions to CF3Ga and CF3In compounds. So, the observed products (CF3)nMBr3–n·L (M = Ga, In; n 1‐3; L = DMF, NMP) are obviously formed by chemical corrosion of the electro‐activated anodes. Finally, electrochemical and chemical trifluoromethylations were successfully carried out, using R3SiCl (R = Me, Vi, Ph), Me3M′Cl (M′ = Ge, Sn) and aluminium anodes or Al‐powder. The products were characterized either after isolation or in the product solutions by NMR‐spectroscopic investigations.
Synthesis and Crystal Structure of >Bis(tetrapropylammonium) Hexabromotellurate(IV)‐bis{dibromoselenate(II)}, [NnPr4]2[TeBr6(SeBr2)2], the Salt of a Mixed‐valence Bromotellurate(IV)‐Selenate(II) Anion
Authors: Janickis Vitalijus , Necas Marek 
Published: August 2008

AbstractDark brown crystals of [NnPr4]2[TeBr6(SeBr2)2] (1) were obtained when selenium and bromine (1:1) were allowed to react in acetonitrile solution in the presence of tellurium(IV) bromide and tetrapropylammonium bromide. The salt 1 crystallizes in the monoclinic space group P21/n with the cell dimensions a = 14.7870(3) Å, b = 9.5523(3) Å, c = 16.7325(3) Å, β = 110.56(10)° (at 123(2) K). In the solid state the [TeBr6(SeBr2)2]2– anion contains a nearly regular [TeBr6] octahedron in which the four equatorial bromo ligands have developed bonds to SeII atoms of the SeBr2 molecules. The contacts between the bridging bromo and the SeII atoms of the SeBr2 molecules are 3.0000(4) and 3.0561(4) Å, and can be interpreted as bonds of the donor‐acceptor type with the bridging bromo ligands as donors and the SeBr2 molecules as acceptors. The TeIV–Br distances are in the range 2.6816(3)–2.7131(3) Å and the SeII–Br bond lengths in the coordinated SeBr2 molecules are 2.3548(4) and 2.3725(4) Å.
Synthesis, Characterization, X‐ray Structures, and Solution Studies of Nickel(II) Complexes of an Aza‐Crown Macrocycle with a Hydroxyl Pendant‐Armed
Authors: Hosseini‐Yazdi Seyed Abolfazl , Khandar Ali Akbar , Azizi Hashem , Aref Amir Reza 
Published: August 2008

AbstractThe 18‐membered mixed‐donor macrocycle 6,7,8,9,10,11,12,13,20,21‐decahydro‐5H, 19H‐dibenzo[b,m][1,15,5,8,11]dioxatriazacyclooctadecin‐20‐ol (L), which contains N3O3 donor set, was synthesized. Also two nickel(II) complexes of L have been synthesized and characterized by X‐ray crystallography, FT‐IR, UV‐Vis absorption spectroscopy and elemental analysis. The structure of complexes shows an unexpected anion dependence. Reaction of Ni(ClO4)2·6H2O with L afforded [NiL](ClO4)2·CH2Cl2 complex in which L uses all donor atoms and acts as a hexadentate ligand so forming a mononuclear nickel(II) complex in distorted octahedral geometry. Contrasting with this, when NiCl2·6H20 is used, the product complex [{NiLCl}2(μ‐Cl)2] is dimeric and consists of two NiLCl units bridged by two chloride ions. The coordination geometry of each nickel atom is a distorted octahedral. In this complex L is exo‐coordinated via only three nitrogen atoms to a nickel ion, which is bound to two cis bridging chloride and one non‐bridging chloride too. Also complexing properties of L towards Ni(ClO4)2·6H2O and NiCl2·6H20 have been determined by UV‐Vis titration in methanol. The computer treatment of the data confirmed the 1:1 metal to ligand stoichiometry for two complexes in solution and gave reliable values for corresponding stability constants (logK = 3.00 ± 0.02 with Ni(ClO4)2·6H2O and logK = 3.29 ± 0.06 with NiCl2·6H20).