bluuebunny/crossref_metadata_2025 huggingface dataset:
The Investigation on Optimum Corrosion Protection Potential of STS 316L in Seawater
Authors: Han Min Su , Park Jae Cheul , Jang Seok Ki , Kim Seong Jong
Published: April 2010

Austenitic stainless steels have problem such as pitting, intergranular corrosion and stress corrosion cracking, which causes severe damage of structure in spite of high toughness and mechanical strength. To minimize these disadvantages in offshore structures demand of STS 316L which has small amount of C and has Mo is increasing. In this paper, the electrochemical experiments are executed to evaluate the durability at various protection potentials on stress corrosion cracking and hydrogen embrittlement of STS 316L in natural sea water environment. The polarization trend for STS 316L shows the effects of concentration polarization due to dissolved oxygen reduction reaction and activation polarization due to hydrogen gas generation. The turning point of two reactions in the polarization curve presented -0.92 V (vs. Ag/AgCl). The lowest current densities in the potentostatic test and non-correded surface condition of specimens by SEM analysis presented at potentials of 0 ~ -0.9 V and 0.4 ~ -0.9 V, respectively. Synthetically, the optimum corrosion protection range without stress corrosion cracking and hydrogen embrittlement is concluded with the potential range of -0.56 V ~ -0.92 V.
Phase Formation in FeOx-SiO2-Cu2O-ZnO-FeS System during Melts Crystallization
Authors: Selivanov Evgeny N. , Gulyaeva R.I. , Selmenskich N.I.
Published: April 2010

The phase formation in oxide-sulphidic systems was studied with the use of X-ray diffraction, mineralography, combined thermogravimetry and calorimetry, in addition to Х-ray spectral microanalysis. The purpose of this work was to estimate the effect of cooling rate of melts in FeOx-SiO2-Cu2O-ZnO-FeS systems on structure and content of the resulting phases. Test subjects were two samples having following compositions (wt. %): I - 40.5 Fe, 2.41 S, 0.87 Cu, 3.87 Zn, 32.1 SiO2 and II - 40.7 Fe, 3.05 S, 8.55 Cu, 4.1 Zn and 19.5 SiO2. Cooling rate of the melts was changed from 0.3 up to 900оС/s.
Heat Treatment Analysis of Large Al-Cu-Mg-Si Alloy Extrusion
Authors: Gariboldi E. , Ripamonti D. , Vedani Maurizio
Published: April 2010

Heat treatable aluminium alloys show their best properties when properly heat treated. Most of the high-strength alloys are usually serviced in the so-called T6 temper consisting of ageing at moderate temperature after a solution treatment and a subsequent quenching. A large extrusion was investigated in this paper. The part was solution annealed at 505°C, water quenched and aged at 160°C for 16 hours. Each stage of the heat treatment is analyzed in this paper in the light of the properties achieved, by experimental investigations and several kinds of numerical simulations. In particular, a thermodynamic calculation (Pandat® software) provides solidification temperatures and equilibrium phases, in order to check whether the solution temperature is adequate. A finite element analysis (performed with COMSOL Multiphysics® software) supplies a simulation of the temperature field during water quenching. The cooling curves obtained are drawn on CCT (Continuous Cooling Transformation) curves, calculated by means of JMatPro® software, to verify if any undesired high temperature precipitation could occur during quenching. Finally, calculated TTT (Time Temperature Transformation) curves can be related to the ageing treatment.Thermal analyses, microstructural investigations and microhardness profile measurements on extrusion sections are also performed to validate calculated results.
Anti-Sticking Properties of PVD CrWNx, CrOx and ZrOx Coatings on Medical Electrode Application
Authors: Hsu Y.L. , Lee C.H. , Chiu S.M. , Sung Y.C. , Yang K.Y. , Chu C.W.
Published: April 2010

The side effect of electrosurgery includes tissue charring, smoke generation and the adhesion of tissue to electrodes. These effects prolong surgery and interfere with effective coagulation. In this paper, CrWNx, CrOx and ZrOx coating were prepared by an unbalanced magnetron sputtering. The microstructure of films was characterized using XRD, XPS, TEM and AFM. The hydrophobicity and surface energy of coatings were calculated by contact angle measurement and Wu harmonic mean approach. Anti-sticking in vitro test was performed by monopolar electrosurgery using pork liver tissue. The hardness of CrWNx , ZrOx and CrOx coatings were 44 GPa, 26.3 GPa and 20.7 GPa, respectively. The CrOx coating had the lowest surface energy 33.5 mN/m and the highest contact angle of water as high as 103°. The high surface O-H bonds density of CrOx coating and N-H bonds density of CrWNx coating could explain about their lower polar component of surface energy. All the three PVD coatings remarkably reduced the quantity of tissue adhesion on the electrode from about 2 times (ZrOx and CrWNx coatings) to 4.88 times (CrOx coating) than uncoated SUS304 electrode.
Finite Volume Methods with Multi-Point Flux Approximation with Unstructured Grids for Diffusion Problems
Authors: Ambrus Jaime , Maliska C.R. , Hurtado F.S.V. , da Silva A.F.C.
Published: April 2010

This paper addresses the key issue of calculating fluxes at the control-volume interfaces when finite-volumes are employed for the solution of partial differential equations. This calculation becomes even more significant when unstructured grids are used, since the flux approximation involving only two grid points is no longer correct. Two finite volume methods with the ability in dealing with unstructured grids, the EbFVM-Element-based Finite Volume Method and the MPFA-Multi-Point Flux Approximation are presented, pointing out the way the fluxes are numerically evaluated. The methods are applied to a porous media flow with full permeability tensors and non-orthogonal grids and the results are compared with analytical solutions. The results can be extended to any diffusion operator, like heat and mass diffusion, in anisotropic media.
Pre-Aging and Maturing Effects on the Precipitation Hardening of an Al-Mg-Si Alloy
Authors: Abid Tahar , Boubertakh A. , Hamamda S.
Published: April 2010

The effect of pre-aging and maturing at room temperature on the hardening response of an Al-Mg-Si alloy is investigated using differential scanning calorimetry (DSC), hardness measurements (Hv) and scanning electron microscopy (SEM).Two experimental conditions are examined. First, natural aging for different times (3 weeks and 1 month) followed by artificial aging at 180°C as a function of time. Second, pre-aging at temperatures in the range 75-100°C followed by artificial aging at 180°C after natural aging for the same periods. The present results indicate that the effect of the pre-aging just after the heating and quenching is used in order to correct the undesirable effect of aging at room temperature. However, during the artificial aging, the alloy hardening becomes faster. Aged samples which have already undergone pre-aging and maturing reveal the precipitation of ''phase. This later phase has the highest hardness value.
Effects of the Microstructure on the Hydrogen Diffusivity in Ni-Based Superalloy 718
Authors: Rosa T.S.A. , Ribeiro A.F. , de Almeida Luiz Henrique , dos Santos Dílson Silva
Published: April 2010

In some applications involving aggressive environments, common in oil and gas industries, superalloys 718 may suffer hydrogen embrittlement, resulting in degradation of mechanical properties. The aim of this work is to study the interaction of hydrogen with different microstructures in a 1 mm thick plate, annealed and age hardened superalloy 718. In this way, the effects of hydrogen interaction on microstructure were studied via thermal programmed desorption (TPD), tensile tests and scanning electron microscopy (SEM). Samples were studied in as-received, artificially aged and overaged conditions. Hydrogenated samples submitted to tensile tests presented ductility loss when compared to hydrogen free samples, showing the hydrogen embrittlement sensitivity of this alloy. The influence of  phase precipitation on hydrogen diffusivity, as a result of aging treatment, was also discussed in this work.
A Study of Photocatalyst of the TiO2 Thin Film with Acid Dispersed CNT for Dye-Sensitized Solar Cell
Authors: Kim Yong Woo , Cho Eun Nara , Choi Soo Chang , Lee Deug Woo
Published: April 2010

M-CNTs (Multiwall Carbon Nano Tubes) can be used as an electrode, transferring electrons and heat very easily. This property helps transfer electrons created in TiO2 layer of DSSC (Dye-sensitized Solar Cell). CNTs layer with TiO2 utilized for the photocatalyst is expected to contribute to improve the efficiency of the solar cell. The Photocatalyst of TiO2 thin film was manufactured from titanium isopropoxide, ethanol, and HCl by a sol-gel process. To determine the property of TiO2 thin film with CNT, we performed to mix acid dispersed CNT in TiO2 Sol-gel and make coating membranes using sol-gel with different densities of CNT. It was found that the crystal structure changed from the anatase phase to the rutile phase having higher efficiency by XRD measure after treatment of high temperature sintering. To demonstrate the property of each sample, the transmittance of the TiO2 thin film was measured by a spectrometer and dispersion of CNT of the thin film was measured by SEM. In conclusion, the capacitance as the parameter which can affect performance of DSSC was investigated.
Diffusion in Al-Ni and Al-NiCr Interfaces at Moderate Temperatures
Authors: Čelko Ladislav , Klakurková Lenka , Švejcar Jiří
Published: April 2010

The diffusion couples for experimental study were prepared by HVOF spraying of nickel and nickel with 20 wt.% of chromium powders onto an aluminium sheet surface. The interfaces with sharp gradients of chemical concentration of these elements were prepared. Annealing at temperatures of 600°C and 630°C, close to the Al + Al3Ni eutectic melting point (639.9°C), with different dwell times were used. During annealing, the reactants diffuse and form layers of Al3Ni2 and Al3Ni intermediate phase compositions. Moreover, nickel without the assistance of chromium diffuses preferably along the grain boundaries into aluminium substrate and produces the strengthening of the substrate by stable Al3Ni and metastable Al9Ni2 particles. The microstructures were obtained by scanning electron microscopy. Layer thickness measurements were realized by means of image analyses. Chemical composition was estimated by energy dispersive microanalysis measurements. According to the results of the analyses performed the average chemical interdiffusion coefficients and Wagner’s integral interdiffusion coefficients were calculated.
Study of the Reactive Diffusion in the Presence of Dissolution of Copper in the Solder Melts
Authors: Drápala Jaromír , Kubíček Petr
Published: April 2010

In this work we give heed especially to the dominating process which is the solid metal A dissolving in the melt B. During the dissolving, the melt B saturates with the metal A and the process is influenced by convections which are characteristic for the given experimental configuration. A theoretical description of the kinetics of the solid phase dissolving in melt will be presented for the case of planar and cylindrical dissolving. The aim is to derive a relation for the interface boundary (t) movement in dependence on time and a time course of growth of the element A concentration in the melt B. There are problems with an accurate determination of the interface boundary movement after certain heating times of specimens, when it is observed experimentally, since intermetallic phases create in the original A metal at both the diffusion and cooling and some phases segregate at the solidifying melt cooling. The rate constant is a fundamental parameter characterizing the dissolving rate at a certain configuration. We present a theoretical description of dissolving of a long metallic cylinder submerged into a melt column and relations for the rate constant determination from the time of the whole metallic cylinder dissolution are derived. In our experiments were performed in which Cu was dissolving in the Sn melt for a Cu cylinder (wire) diameters 0.8÷2.5 mm and the rate constant K (T = 350°C) was determined. Relationships between the solid phase dissolving rate, i.e. the solid phase interface boundary movement (t) in the melt and rates of growth of intermetallic phases in the metal A will be observed. This procedure enables to create surface and subsurface layers of regulated thickness in metallic materials by means of reactive diffusion.
Investigation of the Interfacial Reaction between Optical Glasses and Various Protective Films and Mold Materials
Authors: Chao Choung Lii , Huo Cheng Bang , Chou Wen Chen , Wu Tzung Shian , Ma Kung Jeng , Kuo Chien Huang , Chen Ying Tung , Chao Chung Woei
Published: April 2010

The glass molding process (GMP) is regarded as a very promising technique for mass producing high precision optical components such as spherical/ aspheric glass lenses and free-form optics. However, only a handful of materials can sustain the chemical reaction, mechanical stress and temperature involved in the glass molding process. Besides, almost all of these mold materials are classified as hard-to-machine materials. This makes the machining of these materials to sub-micrometer form accuracy and nanometer surface finish a rather tough and expensive task. As a result, making mold life longer has become extremely critical in the GMP industry. The interfacial chemical reaction between optical glass and mold is normally the main reason for pre-matured mold failure. This research aimed to investigate the interfacial chemical reaction between various optical glasses, different anti-stick coating designs and several mold materials. The results showed that glass composition, coating design (composition, microstructure, thickness), environment (vacuum, air or in protective gas), reaction temperature and time could all have profound effects on the interfacial chemical reaction. Based on the results, a design developed specially for certain glasses is more likely to be the viable way of optimizing the effect of the protective coating.
Theoretical Investigation of the Relation between the Output of a Methane Internal Reforming SOFC and the Composition of the Feedstream
Authors: Vakouftsi E. , Athanasiou C. , Marnellos G. , Coutelieris Frank A.
Published: April 2010

It is a common point for the current fuel cell research to correlate the composition of the feedstream to the output of a Solid Oxide Fuel Cell (SOFC). In this direction, the detailed steady-state transport processes (i.e. the flow regime, the heat transfer, the mass and the charge transport) are mathematically described here. A new mesoscopic mathematical model has been developed through the relative differential equations along with the appropriate boundary conditions, which have been numerically integrated by using the commercially available software CFD-ACE+, in order to calculate the electricity produced by the fuel cell. It is found that the produced current density increases with CH4 percentage in the feeding mixture.
Microstructure and Hydrogenation Property of Mg-6.7 mol% Ni Alloy
Authors: Saitoh Hideyuki , Nakamura H.
Published: April 2010

The relation of the microstructure and hydrogenation property of a hypoeutectic Mg-6.7 mol%Ni alloy consisted of primary Mg crystal and Mg2Ni phase has been investigated. In the case that the specimen has a very fine structure, hydrogen is hardly absorbed into the specimen. The growth of both the primary Mg crystal and Mg2Ni phase allow easy hydrogen penetration, but the growth of the primary Mg crystal is more effective. The highest hydrogenation rate and absorption amount of 5 mass% are obtained when the Mg2Ni phase has a rounded shape.
Depth Resolved XRF and XAS for Enrichment and Oxidation of Mn on Surface of Annealed Fe-Mn Alloys
Authors: Shinoda Kozo , Sato S. , Suzuki Shigeru , Toyokawa Hidenori , Tanida Hajime , Takagaki M. , Terada Yasuko , Uruga Tomoya
Published: April 2010

Alloying elements added to steel for improving surface properties such as corrosion resistance are often enriched to the surface of the alloys during annealing at high temperatures. Their behavior depends on difference in their chemical characters and the condition of annealing. In this study, nondestructive depth-resolved analysis of amount distribution and chemical state of alloying element by using X-ray fluorescence analysis (XRF) technique in combination with X-ray absorption spectroscopy (XAS) in order to characterize the enrichment and oxidation of manganese on the surface layers of an Fe-Mn alloy annealed under low oxygen partial pressure. The experiments were carried out using a two-dimensional detector with geometrical arrangement of grazing exit in detection of fluorescence X-ray emitted from sample surface. The results showed that manganese was enriched to surface layers of the Fe-Mn alloys during annealing at high temperatures and formed as manganese oxide. The preferential oxidation of manganese by annealing under low oxygen partial pressure is considered the driving force for their enrichment on the alloy surface.
Effect of Heat Treatments on the Structural and Mechanical Properties of Ti Thin Films Deposited on Steel Substrates by PVD Method
Authors: Gheriani R. , Halimi Rachid
Published: April 2010

Titanium carbides are well known materials with great scientific and technological interest. The applications of these materials take advantage of the fact that they are very hard, refractory and that they have metallic properties. In this work, we have studied the influence of the heat treatment temperatures (400-1000°C) on the interaction between the titanium thin films and steel substrates. Steel substrates, 100C6 type (AFNOR norms) containing approximately 1 wt % of carbon were coated at 200°C with titanium thin films by magnetron sputtering. The samples were characterized by X-ray diffraction (XRD) and Auger electron spectroscopy (AES). Vikers micro-hardness measurements carried out on the annealed samples showed that the micro-hardness increases with annealing temperature, reaches a maximum (3500 kg/mm2), then decreases progressively. The growth of micro-hardness is due to the diffusion of the carbon, and to the formation of titanium carbide. However, the decrease of micro-hardness is associated with the diffusion of iron and the formation of iron oxide (Fe2O3). At higher temperatures, we note the formation of titanium dioxide (TiO2).
Presentation of a New Method for Determination of Diffusion Coefficients of Gaseous Pollutants in Cladding Wall Materials Indoors
Authors: Gonçalves José J. , Santos Armando S. , Silva Gabriela V. , Fernandes Eduardo O.
Published: April 2010

Diffusion and partition coefficients are two key parameters of importance for the characterization of building materials as sources and sinks of air pollutants indoors. The number of coefficients for each pair ‘chemical compound – material surface’ available in the literature are still scarce and with a high discrepancy in the results obtained by different methods, even for the same method [1]. The objectives of this study were (1) to develop a simple and rapid experimental method for directly measuring the diffusion coefficient (D), and (2) to perform determinations with both the new and the cup method comparing the results obtained. The new method is based on two existent methodologies, the passive sampling on Tenax TA and the dry cup method, proposed by Haghighat et al. [1] and also developed by this research team [2]. The experiments were carried for three different building materials (cork based material, gypsum board and PVC) and three different compounds (cyclohexane, n-octane and m-xylene). The discussion of the results obtained for D by the two methods is presented in this paper. Observed differences were not of the same order of magnitude for the pairs compound/material studied, varying from the order of 101 in the case of PVC to 102 in the gypsum and in the cork. However some facts were the same: the gypsum board presents the higher values of D and PVC the lower values of D for the three compounds studied in both methods. One of the causes of these marked differences could be high difference of the concentration of the compound in the air between the methods, saturation value in cup method (dozens g/m3) and low values typical from indoor environments (few mg/m3) in the proposed method.
Macroporous Silicon Electrochemical Etching for Gas Diffusion Layers Applications: Effect of Processing Temperature
Authors: Kouassi Sebastien , Gautier Gaёl , Desplobain Sebastien , Coudron Loic , Ventura Laurent
Published: April 2010

MEMS technology requires low cost techniques to permit large scale fabrication for production. Porous silicon (PS) can be used in different manner to replace standard expensive etching techniques like DRIE (Deep Reactive Ion Etching). To perform same process quality as the latter, one need to understand how different parameters can influence porous silicon properties. We investigate here local formation of macroporous silicon on 2D and 3D silicon substrates.
The blank substrate is a low doped (26–33 Ω cm) n type 6 inches silicon wafer. Then, an in situ phosphorus-doped polycrystalline silicon (N+ Poly-Si) is deposited on a thermal oxide layer to delimit the regions to be etched. Porous silicon is obtained afterwards using electrochemical anodization in a hydrofluoric acid (HF) solution. The effect of the temperature process on Si-HF electrochemical system voltamperometric curves, macropores morphology and electrochemical etch rates is more specifically studied. Moreover, permeation of porous substrates to hydrogen is studied after various anodization post-treatments such as KOH and HF wet etching or after a thin gold layer deposition used as current collector in micro fuel cells.
Simultaneous Measurements of Lattice and Grain Boundary Diffusion Coefficients via 2-Dimensional Simulations
Authors: Blum Ivan , Portavoce Alain , Mangelinck Dominique , Bernardini Jean , Hoummada Khalid , Daineche Rachid , Lábár János L. , Carron Véronique
Published: April 2010

A method is presented to measure lattice and grain boundary diffusion coefficients using secondary ion mass spectroscopy and 2-dimensional diffusion simulations. SIMS is used to measure concentration profiles of implanted species before and after annealing. The as-implanted concentration profile is used as the initial condition for 2-dimensional diffusion simulations using the finite element method. The geometry of the simulation is based on the microstructure of the sample observed by transmission electron microscopy. Both lattice and grain boundary diffusion are simulated. The final 2-dimensional concentration distribution is projected on the depth axis to obtain a simulated depth profile. The diffusion coefficients are adjusted to fit the profiles measured after annealing. We find that this method allows to determine simultaneously and independently the lattice and grain boundary diffusion coefficients from the same profiles. This method is used to measure the diffusion coefficients of As in polycrystalline Ni2Si thin films. The simulations are found to fit the measured profiles with accuracy. The coefficients are measured between 550 and 700°C. An activation energy ratio Qgb/Qv is found greater than one. This result is corroborated by existing data in silicides and is compared to results in other materials for discussion.
Endothelial Cells Augment the Suppressive Function of CD4+CD25+Foxp3+ Regulatory T Cells: Involvement of Programmed Death-1 and IL-10
Authors: Bedke Tanja , Pretsch Leah , Karakhanova Svetlana , Enk Alexander H. , Mahnke Karsten
Published: April 2010

Blood endothelial cells (ECs) act as gatekeepers to coordinate the extravasation of different T cell subpopulations. ECs express defined panels of adhesion molecules, facilitating interaction with blood circulating T cells. In addition to the mere adhesion, this cellular interaction between ECs and transmigrating T cells may also provide signals that affect the phenotype and function of the T cells. To test the effects of ECs on regulatory T cells (Treg) we set up cocultures of freshly isolated murine Treg and primary ECs and assessed the phenotype and function of the Treg. We show that Treg upregulate programmed death-1 (PD-1) receptor expression, as well IL-10 and TGF-β secretion after contact to ECs. These changes in phenotype were accompanied by an increased suppressive capacity of the Treg. Blockade of the PD-1 and/or the IL-10 secretion in the in vitro suppression assays abrogated the enhanced suppressive capacity, indicating relevance of these molecules for the enhanced suppressive activity of Treg. In aggregate, our data show, that ECs increase the immunosuppressive potential of activated Treg by upregulation of PD-1 and stimulation of the production of high levels of IL-10 and TGF-β. Therefore, one can speculate that Treg during transendothelial transmigration become “armed” for their suppressive function(s) to be carried out in peripheral tissues sites.
Depletion of Dendritic Cells Enhances Susceptibility to Cell-Free Infection of Human T Cell Leukemia Virus Type 1 in CD11c-Diphtheria Toxin Receptor Transgenic Mice
Authors: Rahman Saifur , Manuel Sharrón L. , Khan Zafar K. , Wigdahl Brian , Acheampong Edward , Tangy Frederic , Jain Pooja
Published: April 2010

Human T cell leukemia virus type 1 (HTLV-1) is associated with two immunologically distinct diseases: HTLV-1–associated myelopathy/tropical spastic paraparesis and adult T cell leukemia. The genesis of these diseases is believed to be associated with the route (mucosa versus blood) and mode (cell-free versus cell-associated) of primary infection as well as the modulation of dendritic cell (DC) functions. To explore the role of DCs during early HTLV-1 infection in vivo, we used a chimeric HTLV-1 with a replaced envelope gene from Moloney murine leukemia virus to allow HTLV-1 to fuse with murine cells, which are generally not susceptible to infection with human retroviruses. We also used a CD11c-diphtheria toxin receptor transgenic mouse model system that permits conditional transient depletion of CD11c+ DCs. We infected these transgenic mice with HTLV-1 using both cell-free and cell-associated infection routes in the absence and presence of DCs. The ablation of DCs led to an enhanced susceptibility to infection with cell-free but not cell-associated HTLV-1 in both CD4 and non-CD4 fractions, as measured by the proviral load. Infection with cell-free virus in the absence of DCs was also found to have increased levels of Tax mRNA in the non-CD4 fraction. Moreover, depletion of DCs significantly dampened the cellular immune response (IFN-γ+CD8+ T cells) against both cell-free and cell-associated virus. These results uniquely differentiate the involvement of DCs in early cell-free versus late cell-associated infection of HTLV-1 and highlight a significant aspect of viral immunopathogenesis related to the progression of adult T cell leukemia and HTLV-1–associated myelopathy/tropical spastic paraparesis after the initial infection.
Ethanol Upregulates Glucocorticoid-Induced Leucine Zipper Expression and Modulates Cellular Inflammatory Responses in Lung Epithelial Cells
Authors: Gomez Marla , Raju Sammeta V. , Viswanathan Anand , Painter Richard G. , Bonvillain Ryan , Byrne Patrick , Nguyen Doan H. , Bagby Gregory J. , Kolls Jay K. , Nelson Steve , Wang Guoshun
Published: April 2010

Alcohol abuse is associated with immunosuppressive and infectious sequelae. Particularly, alcoholics are more susceptible to pulmonary infections. In this report, gene transcriptional profiles of primary human airway epithelial cells exposed to varying doses of alcohol (0, 50, and 100 mM) were obtained. Comparison of gene transcription levels in 0 mM alcohol treatments with those in 50 mM alcohol treatments resulted in 2 genes being upregulated and 16 genes downregulated by at least 2-fold. Moreover, 0 mM and 100 mM alcohol exposure led to the upregulation of 14 genes and downregulation of 157 genes. Among the upregulated genes, glucocorticoid-induced leucine zipper (GILZ) responded to alcohol in a dose-dependent manner. Moreover, GILZ protein levels also correlated with this transcriptional pattern. Lentiviral expression of GILZ small interfering RNA in human airway epithelial cells diminished the alcohol-induced upregulation, confirming that GILZ is indeed an alcohol-responsive gene. Gene silencing of GILZ in A549 cells resulted in secretion of significantly higher amounts of inflammatory cytokines in response to IL-1β stimulation. The GILZ-silenced cells were more resistant to alcohol-mediated suppression of cytokine secretion. Further data demonstrated that the glucocorticoid receptor is involved in the regulation of GILZ by alcohol. Because GILZ is a key glucocorticoid-responsive factor mediating the anti-inflammatory and immunosuppressive actions of steroids, we propose that similar signaling pathways may play a role in the anti-inflammatory and immunosuppressive effects of alcohol.
Tumor-Primed, In Vitro-Activated CD4+ Effector T Cells Establish Long-Term Memory without Exogenous Cytokine Support or Ongoing Antigen Exposure
Authors: Wang Li-Xin , Plautz Gregory E.
Published: April 2010

Tumor-reactive T cells can be primed in vivo, then activated in vitro to provide numerical expansion and uniform acquisiton of effector phenotype and function. Adoptive transfer of effector T cells mediates complete regression of established tumors in animal models. Some experimental models indicate that extensive in vitro proliferation of T cells inhibits efficacy and that central memory T cells (TCM) provide greater activity than effector memory T cells (TEM). Clinical studies also demonstrate that persistence of adoptively transferred T cells is associated with therapeutic response, thus identifying that conditions to maximize effector cell numbers yet retain memory function are important. In this article, we demonstrate that adoptive transfer of in vitro activated effector CD4+ T cells into tumor-free congenic mice mediates rejection of tumor challenge 9 mo later, at which time T cells re-express activation markers and undergo rapid proliferation at tumor sites. Analysis of the phenotype of memory cells in lymphoid tissues following adoptive transfer shows high CD44 expression with heterogeneous expression of CD62L, indicating a mixture of TEM and TCM phenotypes. Memory cells were sorted into two subsets based on CD62L expression levels and then activated in vitro. Although TEM cells proliferated more rapidly, TEM and TCM cells acquired effector phenotype and function. These data indicate that controlled in vitro expansion of tumor-reactive T cells for adoptive immunotherapy also provides a competent memory response.
High-Throughput Screening for TLR3–IFN Regulatory Factor 3 Signaling Pathway Modulators Identifies Several Antipsychotic Drugs as TLR Inhibitors
Authors: Zhu Jianzhong , Smith Kevin , Hsieh Paishiun N. , Mburu Yvonne K. , Chattopadhyay Saurabh , Sen Ganes C. , Sarkar Saumendra N.
Published: April 2010

TLR3 is one of the major innate immune sensors of dsRNA. The signal transduction pathway activated by TLR3, upon binding to dsRNA, leads to the activation of two major transcription factors: NF-κB and IFN regulatory factor (IRF) 3. In an effort to identify specific chemical modulators of TLR3–IRF3 signal transduction pathway, we developed a cell-based readout system. Using the IFN-stimulated gene 56 promoter-driven firefly luciferase gene stably integrated in a TLR3-expressing HEK293 cell line, we were able to generate a cell line where treatment with dsRNA resulted in a dose-dependent induction of luciferase activity. A screen of two pharmacologically active compound libraries using this system identified a number of TLR3–IRF3 signaling pathway modulators. Among them we focused on a subset of inhibitors and characterized their mode of action. Several antipsychotic drugs, such as sertraline, trifluoperazine, and fluphenazine, were found to be direct inhibitors of the innate immune signaling pathway. These inhibitors also showed the ability to inhibit IFN-stimulated gene 56 induction mediated by TLR4 and TLR7/8 pathways. Interestingly, they did not show significant effects on TLR3-, TLR7-, and TLR8-mediated NF-κB activation. Detailed analysis of the signaling pathway indicated that these drugs might be exerting their inhibitory effects on IRF3 via PI3K signaling pathway. The data presented in this study provide mechanistic explanation of possible anti-inflammatory roles of some antipsychotic drugs.
Particle transport in lakes: Models and measurements
Authors: Weilenmann Ulrich , O'Melia Charles R. , Stumm Werner
Published: April 2010

Results of experimental measurements and mathematical modeling demonstrate that coagulation in lakes can be sufficiently rapid and extensive to affect suspended particle concentrations and sedimenting fluxes significantly. The process dominates particle removal in Lake Zürich and substantially influences particle concentrations in the water column of Lake Sempach.

Natural coagulation in lakes is a process that is strongly influenced by solution chemistry. Calcium ions act as destabilizing agents and enhance natural coagulation while dissolved natural organic matter stabilizes particles and retards coagulation. Since solution chemistry varies widely among lakes, natural coagulation rates are expected to differ among lacustrine systems. Field observations of Lakes Zürich and Sempach support this view. Although primary productivity in Lake Zürich is considerably lower than in Lake Sempach, higher sedimenting fluxes are observed in Lake Zürich. The waters of Lake Zürich are low in dissolved organic carbon, permitting rapid coagulation in the epilimnion of the lake and producing correspondingly rapid sedimentation rates. Colloidal stability can be a factor in eutrophication.
Tomales Bay, California: A case for carbon‐controlled nitrogen cycling
Authors: Smith S. V. , Hollibaugh J. T. , Dollar S. J. , Vink S.
Published: April 2010

Data collected over the summer–autumn dry season in Tomales Bay, California, demonstrate that system to be exporting dissolved P and importing dissolved fixed N. A simple explanation for the observed pattern is net system heterotrophy by about 8%, with <2% of the system primary production of organic C being oxidized by denitrification. The loss of fixed N to denitrification consumes the dissolved inorganic N (DIN) liberated through the 8% excess organic oxidation over organic production. There is a small hydrographic loss of dissolved organic N (DON). The DIN deficit for primary production is therefore caused by the system C metabolism. Thus, C metabolism has profound effect on the N cycle, even though this denitrification rate is trivial to the C cycle. We believe that this pattern of C#x2010;controlled N cycling has wide general application.
Marine humic and fulvic acids: Their effects on remote sensing of ocean chlorophyll
Authors: Carder Kendall L. , Steward Robert G. , Harvey George R. , Ortner Peter B.
Published: April 2010

Marine humic and fulvic acids were concentrated from about 1,400 liters of seawater from the Gulf of Mexico, and specific absorption coefficients were measured for each from 240 to 675 nm. Spectral absorption coefficients were then calculated for Gulf of Mexico stations where earlier data on humic and fulvic acid concentrations were available. Marine humic and fulvic acid values have low molecular weights consistent with extrapolations from soil#x2010;derived curves of their specific absorption coefficients vs. molecular weight. Marine fulvic and humic acids appear to account for most if not all water color or Gelbstoff in the offshore regions of the Gulf of Mexico. Based on a remote#x2010;sensing reflectance model, it appears that the increase in the Gelbstoff: chlorophyll ratio for waters adjacent to and downstream from regions of high primary productivity accounts for much of the deviation found for such waters from the global chlorophyll algorithm of the Coastal Zone Color Scanner.
Estimated near‐surface mesoplanktonic bioluminescence in the western North Atlantic during July 1986
Authors: Batchelder Harold P. , Swift Elijah
Published: April 2010

Mesoplankton samples (retained by 202#x2010;µm mesh) were collected with oblique net hauls from 150 m to the surface along 62°W from 30°N (Sargasso Sea) to 44°30′N (Nova Scotia shelf) in July 1986. The amount of bioluminescence produced by mechanically stimulating individual bioluminescent organisms (ostracods, copepods, cuphausiids) to exhaustion (TMSL) was measured with a shipboard photometry system. The TMSL values combined with individual organism abundances from the net tows provided an estimate of total near#x2010;surface bioluminescent potential. It was greater (11.4 × 1014 photons m−2) in the Sargasso Sea than in the Slope Water north of the Gulf Stream (3.0 × 1014 photons m−2). In the Sargasso Sea, Pyrocystis noctiluca was the major light producer south of 39°N, but became less important between 39°N and 42°N. In Slope Water, north of 42°N, the copepod Metridia lucens was responsible for 90% of the potential near#x2010;surface bioluminescence produced by mesoplankton.
Optimal foraging theory as a predictor of chemically mediated food selection by suspension‐feeding copepods
Authors: DeMott William R.
Published: April 2010

Chemically mediated food selection was studied by offering copepods pairs of particles which differed in nutritional quality or size. Eudiaptomus spp. fed in varying concentrations of algae and polystyrene spheres, high#x2010;quality algae of different sizes, toxic and nontoxic algae, digestible and digestion#x2010;resistant algae, live and dead algae, and dead algae with and without attached bacteria.

Experiments with polystyrene spheres showed that the rejection of nonfood particles did not interfere with feeding on relatively scarce algae. Particle selection in mixtures of algae exhibited good agreement with predictions of optimal foraging theory. Selectivity did not change with food concentration for mixtures of high#x2010;quality algae or mixtures of toxic and nontoxic algae. Copepods showed a weak but consistent preference for the larger of a pair of high#x2010;quality algae, whereas a toxic blue#x2010;green bacterium was eaten at a very low rate whether offered alone or in combination with an edible alga. Selection against low#x2010;quality nontoxic particles (e.g. digestion#x2010;resistant algae), however, was sensitive to food concentration. Discrimination against low#x2010;quality particles was strong when high#x2010;quality food was abundant and weak when high#x2010;quality food was scarce. In agreement with theory, diet selection by Eudiaptomus spp. is strongly influenced by both particle quality and the abundance of alternative foods.
Phagotrophic sustenance of a metalimnetic phytoplankton peak
Authors: Bird D. F. , Kalff J.
Published: April 2010

Evidence is provided for the importance of phagocytosis to mixotrophic chrysophycean algae and to the phytoplankton community as a whole. First, we confirmed the major assumption of past work that the constituents of ingested particles are incorporated efficiently into algal tissue. Cells of the phagotrophic chrysomonad Dinobryon sertularia collected from Lac Gilbert, Quebec, incorporated carbon from radiolabeled bacterial prey with 54% efficiency (95% C.L. = 40–79%) over a 5#x2010;h period. When removed from labeled bacteria, the loss of previously incorporated label from Dinobryon was undetectable over a 4#x2010;h period. We conclude that this alga’s quantitative utilization of prey tissue is indistinguishable from that of purely heterotrophic organisms. Second, simultaneous measurements were made of phagotrophic feeding and photosynthesis within a highly concentrated layer of chrysomonads (Dinobryon and Ochromonas) in the metalimnion of Lac Gilbert on 3–4 July 1986. Chrysomonad abundance ranged from 300 cells ml−1 at 6 m, to 9,000 at 7 m, and back to <100 at 9 m. At the 7#x2010;m peak, phagotrophy accounted for 79% of algal community carbon assimilation on this overcast day.
Protozoans in two southeastern blackwater rivers and their importance to trophic transfer
Authors: Carlough Leslie A. , Meyer Judy L.
Published: April 2010

Protozoan population densities in the sixth#x2010;order Ogeechee River and fourth#x2010;order Black Creek ranged from 6 × 104 to 11 × 106 flagellates liter−1 and 0 to 1.5 × 105 ciliates liter−1 over a 12#x2010;month period. These numbers approximate those reported for various marine and freshwater habitats. A microcosm study with Ogeechee River water showed a density increase from 4 × 105 to 9 × 106 flagellates liter−1 and 7 × 103 to 4 × 105 ciliates liter−1 in 2 d, representing an estimated net protozoan production of 600 µg C liter−1 d−1. This production was mainly attributed to bacterial growth on DOC and subsequent grazing by the protozoans. Although problems always accompany container studies, this indicates an immense potential for protozoan production in the river. Daily transport of protozoan carbon ranged from 1.08 to 1,360 g, and annual estimated transport downstream was 60 t of protozoan carbon in the Ogeechee River. Densities of filter#x2010;feeding macroinvertebrates are very high in this river. Many of the filter#x2010;feeding species are known to feed primarily on amorphous material in the seston, within which protozoans consitute about 4% by carbon content. Since protozoans can be assimilated at relatively high efficiency (∼50%), they appear to be a trophic link between the metazoans and otherwise unavailable carbon sources in blackwater rivers.
The spatial distribution of larvalfishes about the Mississippi River plume
Authors: Govoni John J. , Hoss Donald E. , Colby David R.
Published: April 2010

The distribution of larval fishes is shaped by the Mississippi River plume at both coarse (kilometers) and fine (tens to hundreds of meters) spatial scales. Density estimates of larval fishes (No. m−3), based upon ichthyoplankton samples collected about the Mississippi River plume in February 1982, December 1982, and November 1983, were often greater by a factor of 10, and sometimes by several orders of magnitude, at the plume front than they were inside (within) or outside of the plume. Greater densities at the plume front were most apparent for larval Brevoortia patronus (a clupeid) and unidentified clupeid larvae. Frontal convergence apparently affects the accumulation of larval fishes at the frontal interface, but high densities were not evident everywhere along the front. An index of potential convergent velocity indicates maximal velocities of the order of 0.10–0.30 m s−1, but this index does not explain variation in the accumulation of larval fishes. Frontal convergence may be localized and affected by secondary circulations.
Computation of aquatic primary production: Extended formalism to include effect of angular and spectral distribution of light
Authors: Sathyendranath Shubha , Platt Trevor
Published: April 2010

With a new spectral model of the underwater light field and an extended formalism for the light#x2010;saturation curve, it is shown that the angular distribution of underwater light has to be considered to account correctly for light absorption and utilization by algal cells. Neglecting the effect of angular distribution on the light absorbed by phytoplankton can lead to underestimation of primary production. For the stations studied as examples, the minimum correction required is 5–13% for daily, column#x2010;integrated production. For instantaneous primary production, the error is greater when the solar zenith angle is larger (higher latitudes, early morning, and late afternoon). In the extended formalism, models of photosynthesis based on light absorbed are shown to have a more rigorous foundation than those based on light available.
[Methyl‐3H]thymidine macromolecular incorporation and lipid labeling: Their significance to DNA labeling during measurements of aquatic bacterial growth rate
Authors: Robarts Richard D. , Wicks Richard J.
Published: April 2010

It is essential during measurements of aquatic bacterial production with [methyl#x2010;3H]thymidine (Tdr) that only labeled DNA is measured. We found in 12 freshwater and marine systems that DNA labeling represented a variable proportion of total macromolecular labeling. Up to 87% of label appearing in precipitated labeled macromolecules from acid#x2010;base hydrolysis treatments was soluble in ethanol. Reverse#x2010;phase, high#x2010;pressure liquid chromatography showed that the composition of labeled molecules in the ethanol was 78–88% [3H]Tdr. The rate of labeling of the ethanol#x2010;soluble fraction was significantly correlated with the rate of total macromolecular labeling (r = 0.88, n = 40, P < 0.001) and less strongly with the DNA labeling rate (r = 0.49, n = 28, P = 0.005). Experiments in which bacterial cells were labeled with [3H]Tdr or32PO43− showed that above a total macromolecular labeling rate of ∼1 pmol Tdr liter−1 h−1, bacterial cells bind Tdr but do not incorporate it into phospholipids in the cell envelope.
Short‐term changes in the erodibility of intertidal cohesive sediments related to the migratory behavior of epipelic diatoms
Authors: Paterson David M.
Published: April 2010

The surface stability of intertidal cohesive sediments maintained in a laboratory tidal ecosystem was examined in relation to the migratory behavior of epipelic diatoms. Stability was measured by a new portable device—a cohesive strength meter. Diatom#x2010;inhabited sediments increased significantly in surface stability over 7.3#x2010;h tidal exposure as compared with consolidated and unconsolidated control sediments. Low#x2010;temperature scanning electron microscopy showed an extensive extracellular matrix throughout the surface of diatom#x2010;inhabited sediments. This matrix was considered to consist mainly of mucopolysaccharides produced by diatoms as part of their locomotive mechanism. A matrix of very fine strands (possibly of bacterial origin) was found on the consolidated control sediment but had little effect on stability. Surface stability imparted by the mucilage produced by epipelic diatoms decayed after the return of the tide, but when dense populations of diatoms were present (106 diatoms cm−2) some residual stability remained after a full tidal inundation.
A positive relationship between groundwater velocity and submersed macrophyte biomass in Sparkling Lake Wisconsin
Authors: Lodge David M. , Krabbenhoft David P. , Striegl Robert G.
Published: April 2010

We measured groundwater velocity and submersed macrophyte biomass at 52 shallow (0.4–6.6 m) sites in mesotrophic Sparkling Lake, Vilas County, Wisconsin, during May–August 1985. Seventeen percent of variation in macrophyte biomass was explained by a significant (P < 0.005) relation with depth [log(biomass + 1) = 0.49 depth − 0.08 (depth)2 + 0.12]. Some of the remaining variation in macrophyte biomass was explained by a significant rank correlation of biomass#x2010;on#x2010;depth residuals with groundwater (rs = 0.46, P < 0.01). These results suggest that water movement through the sediment#x2010;water interface may be a determinant of macrophyte abundance and distribution.
Temperature dependence of Cu(II) carbonate complexation in natural seawater
Authors: Soli Alan L. , Byrne Robert H.
Published: April 2010

Cu(II) carbonate complexation was examined in natural seawater between 5° and 35°C. The reaction enthalpy for the equilibrium Cu2 + CO32− ⇌ CuCO30, expressed in terms of total carbonate ion concentration, is ∼2.5 kcal mol−1. The formation constant swβ1 = [CuCO30] [Cu2+]−1CO32−]T−1, expressed in terms of total carbonate ion concentration in seawater, thus decreases by about 25% between 25° and 5°C.