bluuebunny/crossref_metadata_2025_split huggingface dataset:
Latent TGF‐β1 activation by platelets
Authors: Blakytny Robert , Ludlow Anna , Martin Gail E.M. , Ireland Grenham , Lund Leif R. , Ferguson Mark W.J. , Brunner Georg 
Published: February 2004

AbstractPlatelets are a major source of transforming growth factor‐β1 (TGF‐β1) in the circulation as they release latent growth factor in response to activation. We report here that human platelets, when stimulated with thrombin, activated a significant proportion of the latent TGF‐β released. Latent TGF‐β activation was independent of cytokine release, since activation was delayed compared to platelet degranulation. Activation occured in releasates and did not require the continuous presence of platelets. Classical mechanisms of latent TGF‐β activation were not involved, since activation was not affected by gene deletion and/or inhibitors of the known TGF‐β activators/co‐factors, thrombospondin‐1 (TSP‐1), mannose 6‐phosphate/insulin‐like growth factor‐II receptor (M6P/IGF‐IIR), plasminogen/plasmin, or several other candidate proteases. In contrast, latent TGF‐β activation was significantly inhibited by the furin inhibitors, decanoyl‐Arg‐Val‐Lys‐Arg‐chloromethyl ketone and L‐hexaarginine. We show that platelets contain a furin‐like enzyme which is released upon platelet activation. We conclude that, following activation, platelets release and activate latent TGF‐β1 via mechanisms involving the release and activity of a furin‐like proprotein convertase. This novel mechanism of latent TGF‐β activation might represent an important mediator and therapeutic target of platelet TGF‐β1 functions, for example, in early wound repair, fibrosis, or arteriosclerosis. J. Cell. Physiol. 199: 67–76, 2004© 2003 Wiley‐Liss, Inc.
Phosphorylation of focal adhesion kinase tyrosine 397 critically mediates gastrin‐releasing peptide's morphogenic properties
Authors: Glover Sarah , Delaney Melissa , Dematte Cecile , Kornberg Lori , Frasco Melissa , Tran‐Son‐Tay Roger , Benya Richard V. 
Published: February 2004

AbstractWe have proposed that gastrin‐releasing peptide (GRP) and its receptor (GRP‐R) are morphogens that when aberrantly re‐expressed in colon cancer promote tumor cell differentiation and retard metastasis. Because circumstantial evidence suggested that these properties were mediated via focal adhesion kinase (FAK), the purpose of this study was to elucidate the role of GRP‐induced activation of this enzyme on properties fundamental to metastasis including cell attachment, motility, and deformability. To do this, we studied 293 cells, a non‐malignant epithelial cell line that we show expresses GRP and GRPR. To dissect out the role of FAK, 293 cells were modified to inducibly express the dominant negative enzyme FAK‐related non‐kinase (FRNK) under control of a Tet‐On (i.e., doxycycline‐sensitive) promoter. Under serum‐free conditions, GRP acting in an autocrine manner caused FAK to be phosphorylated at Y397; and this could be completely inhibited either by incubating with the specific GRP‐R antagonist D‐Phe6(bombesin) methyl ester, or by upregulating FRNK using doxycycline. To measure cell attachment, we designed a cone‐plate viscometer that recorded the shear stress required to detach cells from their underlying matrix. To assess motility, confluent cells were wounded and behavior assessed by time‐lapse photography. To measure deformability, we recorded the ability of cells to be completely drawn into a micropipette <50% the size of the non‐deformed cell. Control 293 cells adhered more avidly to their underlying matrix, rapidly remodeled wounded tissues without any increase in overall proliferation, and were less distensible than cells treated with antagonist or doxycycline. Thus, these findings suggest that expression of GRP/GRPR in cancer inhibits metastasis by enhancing cell attachment to the matrix, regulating motility in the context of remodeling, and decreasing deformability. J. Cell. Physiol. 199: 77–88, 2004© 2003 Wiley‐Liss, Inc.
MEKK2 regulates the coordinate activation of ERK5 and JNK in response to FGF‐2 in fibroblasts
Authors: Kesavan Kamala , Lobel‐Rice Katherine , Sun Weiyong , Lapadat Razvan , Webb Saiphone , Johnson Gary L. , Garrington Timothy P. 
Published: February 2004

AbstractMitogen‐activated protein kinases (MAPKs) are regulated by MAPK kinases (MKKs), which are in turn regulated by MKK kinases (MKKKs). While a single MKKK can regulate several different MAPK family members, and several MKKKs can often activate the same MAPK, emerging evidence indicates a unique role for individual MKKKs in acting as signaling nodes to coordinately activate different subsets of MAPKs in response to specific cellular stimuli. Thus, while there is much apparent overlap in MAPK regulation by different MKKKs, each MKKK serves a specific purpose in regulation of unique cellular functions. The purpose of this study was to define the specific role of MEKK2, an MKKK, in MAPK regulation and cell function. MEKK2 coordinately activates the ERK5 and JNK pathways. Targeted disruption of MEKK2 expression causes loss of ERK5 and JNK activation in response to FGF‐2 in mouse embryonic fibroblasts (MEFs). FGF‐2 receptor signaling requires MEKK2 for induction of mRNA for c‐Jun, Fra‐1, and Fra‐2, components of the AP‐1 transcription complex. In FGF‐2‐stimulated MEKK2−/− fibroblasts, c‐Jun phosphorylation is inhibited, consistent with a loss of JNK activation. Thus, MEKK2 regulates AP‐1 activity at two levels, by regulating both expression of AP‐1 components and c‐Jun N‐terminal phosphorylation. One function of the AP‐1 transcription complex is to regulate cytokine gene expression. Expression of IL‐1α, IL‐1β, IL‐6, and TNFα is inhibited in MEKK2−/− fibroblasts. Bacterial lipopolysaccharide (LPS) and TNFα neither activate ERK5 nor require MEKK2 for JNK activation, demonstrating specificity of MEKK2 in FGF‐2 receptor signaling and control of cytokine gene expression. J. Cell. Physiol. 199: 140–148, 2004© 2003 Wiley‐Liss, Inc.
Novel biphasic traffic of endocytosed EGF to recycling and degradative compartments in lacrimal gland acinar cells
Authors: Xie Jiansong , Qian Limin , Wang Yanru , Rose Chadron M. , Yang Tao , Nakamura Tamako , Hamm‐Alvarez Sarah F. , Mircheff Austin K. 
Published: February 2004

AbstractThe purpose of this study was to delineate the traffic patterns of EGF and EGF receptors (EGFR) in primary cultured acinar epithelial cells from rabbit lacrimal glands. Uptake of [125I]‐EGF exhibited saturable and non‐saturable, temperature‐dependent components, suggesting both receptor‐mediated and fluid phase endocytosis. Accumulation of [125I] was time‐dependent over a 120‐min period, but the content of intact [125I]‐EGF decreased after reaching a maximum at 20 min. Analytical fractionation by sorbitol density gradient centrifugation and phase partitioning indicated that within 20 min at 37°C [125I] reached an early endosome, basal–lateral recycling endosome, pre‐lysosome, and lysosome. Small components of the label also appeared to reach the Golgi complex and trans‐Golgi network. Intact [125I]‐EGF initially accumulated in the recycling endosome; the content in the recycling endosome subsequently decreased, and by 120 min increased amounts of [125I]‐labeled degradation products appeared in the pre‐lysosomes and lysosomes. Confocal microscopy imaging of FITC‐EGF and LysoTrackerRed revealed FITC enriched in a dispersed system of non‐acidic compartments at 20 min and in acidic compartments at 120 min. Both confocal immunofluorescence microscopy and analytical fractionation indicated that the intracellular EGFR pool was much larger than the plasma membrane‐expressed pool at all times. Cells loaded with [125I]‐EGF released a mixture of intact EGF and [125I]‐labeled degradation products. The observations indicate that in lacrimal acinar cells, EGFR and EGF–EGFR complexes continually traffic between the plasma membranes and a system of endomembrane compartments; EGF‐stimulation generates time‐dependent signals that initially decrease, then increase, EGF–EGFR traffic to degradative compartments. J. Cell. Physiol. 199: 108–125, 2004© 2003 Wiley‐Liss, Inc.
8‐prenylnaringenin, a novel phytoestrogen, inhibits angiogenesis in vitro and in vivo
Authors: Pepper Michael S. , Hazel Susan J. , Hümpel Michael , Schleuning Wolf‐Dieter 
Published: February 2004

Abstract8‐Prenylnaringenin is a recently discovered phytoestrogen. Using an in vitro model of angiogenesis in which endothelial cells can be induced to invade a three‐dimensional collagen gel within which they form capillary‐like tubes, we demonstrate that 8‐prenylnaringenin inhibits angiogenesis induced by basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), or the synergistic effect of the two cytokines in combination, with an IC50 of between 3 and 10 μM. This effect was seen with bovine microvascular endothelial cells derived from the adrenal cortex (BME cells) and with endothelial cells from the bovine thoracic aorta (BAE cells). The inhibitory effects of 8‐prenylnaringenin were found to be roughly equipotent to those of genistein that has previously been shown to inhibit angiogenesis in vitro. Early chorioallantoic membrane (CAM) assay results showed reductions in both vessel lengths and vein diameters, with similar potency in the 8‐prenylnaringenin and genistein groups. Similar effects on the CAM vessels were seen when the two substances were co‐added. These findings suggest that 8‐prenylnaringenin has potential therapeutic applications for diseases in which angiogenesis is an important component. J. Cell. Physiol. 199: 98–107, 2004© 2003 Wiley‐Liss, Inc.
Effects of inorganic anions on photoactivity of various photocatalysts under different conditions
Authors: Hu Chun , Yuchao Tang , Lanyu Lin , Zhengping Hao , Yizhong Wang , Hongxiao Tang 
Published: February 2004

AbstractThe effects of inorganic anions (SO42−, H2PO4−, HCO3−, F−) on the photoactivity of surface bond‐conjugated TiO2/SiO2 and Fe–TiO2/SiO2 for the photodegradation of Acid Red B were investigated. The introduction of iron changed the chemical environment of lattice titanium and the surface charge properties of TiO2/SiO2. Fe–TiO2/SiO2 inhibited the negative role of the selected inorganic anions. The effects of different light sources and dyes of various structure, with a sulfonate group, on the role of F− in decolorization of Acid Red B were examined. F− has the same negative influence on the photoactivity of TiO2/SiO2 with the blacklight lamp and solar irradiation, but shows no influence upon irradiation with the 254 nm lamp. The tested inorganic anions affected the photodegradation of dyes by controlling their adsorption onto the surface of the catalyst and by trapping h+ and •OH. Copyright © 2004 Society of Chemical Industry
The use of 3,3′,4′,5‐tetrachlorosalicylanilide as a chemical uncoupler to reduce activated sludge yield
Authors: Chen Ying Xu , Ye Fen Xia , Feng Xiao Shan 
Published: February 2004

AbstractTo determine whether chemical additions can be used to reduce sludge production in biological wastewater treatment, 3,3′,4′,5‐tetrachlorosalicylanilide (TCS) was added to activated sludge cultures as a metabolic uncoupler. Batch tests confirmed that TCS is an effective chemical uncoupler in reducing the sludge yield at concentrations greater than 1.0 mg dm−3; a TCS concentration of 1.0 mg dm−3 reduced sludge yield by approximately 50%. Substrate removal capability and effluent nitrogen concentration were not affected adversely by the presence of TCS when dosed every other day in a range of 2.0–3.6 mg dm−3 during the 40‐day operation of activated sludge batch cultures. Such sludge growth reduction was associated with the enhancement of microbial activities in terms of the specific oxygen uptake rate and dehydrogenase activity. Sludge settleability of the treated and control samples was qualitatively comparable and not significantly different. Filamentous bacteria continued to grow in sludge flocs only in the control reactor at the end of the 40‐day trial. These results suggest that TCS treatment of activated sludge systems may reduce excess sludge yield. Copyright © 2003 Society of Chemical Industry
Phenol degradation in a fixed‐bed bioreactor using micro‐cellular polymer‐immobilized Pseudomonas syringae
Authors: Erhan E , Yer E , Akay G , Keskinler B , Keskinler D 
Published: February 2004

AbstractHighly porous (85% void volume) polymer beads with interconnecting micro‐pores were prepared for the immobilization of Pseudomonas syringae for the degradation of phenol in a fixed‐bed column bioreactor. The internal architecture of this support material (also known as PolyHIPE Polymer) could be controlled through processing before the polymerization stage. The transient and steady state phenol utilization rates were measured as a function of substrate solution flow rate and initial substrate concentration. The spatial concentration of the bacteria on the micro‐porous support particles as well as within them was studied using scanning electron microscopy at various time intervals during the continuous operation of the bioreactor. It was found that although bacterial penetration into the porous support was present after 20 days, bacterial viability however, was compromised after 120 days as a result of the formation of a biofilm on the support particles. The steady state phenol utilization at an initial phenol concentration of 200 mg cm−3 was 100% provided that the flow rate was less than 7 cm3 min−1. Substrate inhibition at a constant flow rate of 4.5 cm3 min−1 was found to begin at 720 mg dm−3. The critical dilution rate for bacteria washout was high as a result of the highly hydrophobic nature of the support and the reduction of pore interconnect size due to bacterial growth within the pores in the vicinity of the surface of the support. Copyright © 2004 Society of Chemical Industry
Fed‐batch culture of hybridoma cells in serum‐free medium using an optimized feeding strategy
Authors: Zhang Li , Shen Hong , Zhang Yuanxing 
Published: February 2004

AbstractThe achievement of high cell density and monoclonal antibody concentration depends on understanding cell metabolism and the control of cell culture. A model of cell metabolism and monoclonal antibody production in hybridoma cell culture is presented. Fed‐batch culture in serum‐free medium was conducted in a bioreactor with an optimized feeding strategy according to the model. In the process, nutrient concentrations, especially glucose and glutamine, were maintained at relatively constant and low levels. The formation of toxic byproducts, such as ammonia and lactate, was greatly reduced in comparison with that in non‐optimized batch culture. The concentration of monoclonal antibody reached 350 mg dm−3, which was seven times greater than in non‐optimized batch culture. Copyright © 2003 Society of Chemical Industry
Advanced oxidation processes for destruction of cyanide from thermoelectric power station waste waters
Authors: Monteagudo José M , Rodríguez Lourdes , Villaseñor José 
Published: February 2004

AbstractSeveral advanced oxidation processes for the destruction of cyanide contained in waste waters from thermoelectric power stations of combined‐cycle were studied. Thus, oxidation processes involving ozonation at basic pH, ozone/hydrogen peroxide, ozone/ultraviolet radiation and ozone/hydrogen peroxide/ultraviolet radiation have been carried out in a semi‐batch reactor. All these methods showed that total cyanide can be successfully degraded but with different reaction rates, and the decrease in the total cyanide concentration can be described by pseudo‐first order kinetics. The influence of pH and initial concentration of hydrogen peroxide was studied to find the optimal conditions of the oxidation process. Experimental results of the single ozone treatment indicated that total cyanide is destroyed more rapidly at higher pH (12), while ozonation combined with H2O2 and/or UV is faster at pH 9.5. The optimum concentration of H2O2 was 20.58 × 10−2 M because an excess of peroxide decreases the reaction rate, acting as a radical scavenger. The total cyanide degradation rate in the O3/H2O2(20.58 × 10−2 M) treatment was the highest among all the combinations studied. However, COD reduction, in the processes using UV radiation such as O3/UV or O3/H2O2/UV was about 75%, while in the processes with H2O2 and/or O3/H2O2 was lower than 57% and was insignificant, when using ozone alone. Copyright © 2003 Society of Chemical Industry
Effect of floc concentration on the rheology of a ferric floc
Authors: McMinn Wendy AM , Keown James , Allen Stephen J , Burnett Michael G 
Published: February 2004

AbstractThe primary interest of this work is to determine the effect of floc concentration on ferric floc particle interactions and hence, rheology. In accordance with established theory, ferric floc viscosity exhibits a non‐linear increase with solids content, with the viscosity increasing sharply above a concentration of 12 000 ppm. Shear effectively breaks down floc structure, and thus reduces viscosity, the extent of which is independent of solids content. The effect of shear is also observed to diminish over time and can be adequately characterised by a power law model. Addition of aluminium nitrate to ferric floc increases the quantity of water bound within the floc, and thus produces suspensions which are more viscous in nature. Copyright © 2003 Society of Chemical Industry
Partial thiosulfate oxidation by steady‐state continuous culture in a bioreactor‐settler system
Authors: Velasco Antonio , Alcántara Sergio , Razo‐Flores Elías , Revah Sergio 
Published: February 2004

AbstractThe design, characterization, and performance of a bioreactor‐settler system that allows the partial biological oxidation of reduced sulfur compounds is described. The design incorporates the physical separation of the aeration from the bioreactor. The reactor has a dynamic flow zone and a static zone. Steady state thiosulfate‐oxidizing cultures were established at different O2/S2O32− molar ratios. At O2/S2O32− molar ratios > 1.0, sulfate was the main product of the biological oxidation of thiosulfate, while below O2/S2O32− molar ratios of about 1.0, formation of elemental sulfur was observed. The maximum sulfur formation (60%) was obtained at a molar ratio of 0.98. The elemental sulfur settled in the bottom of the bioreactor and was removed daily from the system. A recovery efficiency of 70% was obtained. The settled sulfur–biomass particles consisted of 90% sulfur and 6% biomass and had an average size of 150 µ m and a sedimentation rate of 7.50 m h−1. The hydraulic retention time (HRT of 2 min) of the medium in the aerator vessel showed an influence over the system performance due to the oxidation of thiosulfate and intermediates under the high oxygen concentration found in this vessel. Copyright © 2003 Society of Chemical Industry
Liquid membrane transport and separation of Zn2+ and Cd2+ from sulfate media using organophosphorus acids as mobile carriers
Authors: Juang Ruey‐Shin , Kao Hsiang‐Chien , Wu Wen‐Hsin 
Published: February 2004

AbstractThe transport and separation of Zn2+ and Cd2+ from binary sulfate solutions in a supported liquid membrane using di(2‐ethylhexyl)phosphoric acid (D2EHPA) and 2‐ethylhexylphosphonic acid mono‐2‐ethylhexyl ester (PC88A) as mobile carriers was studied. Batch solvent extraction experiments were conducted to obtain the reaction stoichiometries. Experiments were performed at different metal concentrations (1.4–14.5 mol m−3), metal concentration ratios (0.4–9.2), pH (2–5), and carrier concentrations (0.1–0.6 mol dm−3). A mass transfer model was proposed that considers diffusion in the aqueous feed and strip stagnant layers, and within the membrane. The interfacial reactions were assumed to approach equilibrium instantaneously. It was shown that the proposed model was applicable for binary Zn2+/Cd2+ systems (standard deviation, 5%). The larger separation factors of Zn2+ over Cd2+ with PC88A than D2EHPA under equilibrium (batch solvent extraction) and non‐equilibrium (liquid membrane) conditions were also evaluated and discussed. Copyright © 2003 Society of Chemical Industry
Vegetable oil degumming with polyimide and polyvinylidenefluoride ultrafiltration membranes
Authors: Pagliero Cecilia , Ochoa Nelio , Marchese José , Mattea Miguel 
Published: February 2004

AbstractThe removal of phospholipids (‘degumming’) is the first step in the process of refining crude vegetable oil. Membrane separation has been often proposed as an alternative to the conventional procedure (water degumming). Until now, the instability of polymeric membranes in organic solvents has been the major obstacle in applying this technique. In this work, a local synthesized polyvinylidenefluoride (PVDF) and a commercial polyimide (PI) membrane were evaluated for their flux and rejection properties during degumming of soybean oil in a laboratory‐scale cross‐flow ultrafiltration cell. Degumming experiments were done at different temperatures and feed flows, keeping constant both the feed concentration and the transmembrane pressure. PVDF and PI membranes gave selectivity values and permeate color that did not differ significantly from each other. Retention coefficients larger than 98% were obtained in all cases. In every experiment, a decline in permeate flux with time occurred at the beginning of the degumming process. By increasing the feed rate, a higher permeate flux was obtained. The results show that the PVDF membrane had a higher productivity than the PI one. Copyright © 2003 Society of Chemical Industry
An integrated process of oxidative coupling of methane and pyrolysis of naphtha in a scaled‐up unit
Authors: Czechowicz Dymitr , Skutil Krzysztof , Tórz Artur , Taniewski Marian 
Published: February 2004

AbstractA heat‐effective ‘integrated’ process of C2H4 production, incorporating exothermic oxidative coupling of methane (OCM) carried out in the catalytic section of a flow tubular reactor, and endothermic pyrolysis of naphtha carried out in the postcatalytic section of the same reactor, studied earlier in a small silica reactor, was examined now in a scaled‐up unit with a stainless‐steel (1H18N9T) reactor (volume 400 cm3, Li/MgO catalyst bed 165 cm3). It was demonstrated that depending on the operating conditions, such an integrated process could be realized over a wide range of the relative contribution of the two component processes, leading always to an increase in the C2H4 yield, as compared with OCM or pyrolysis alone. A high degree of additivity of the yields of all products was observed in all cases, independently of the relative contribution of OCM and pyrolysis. Such results indicated that in the scaled‐up unit with a stainless‐steel reactor, the interactions between the component processes and products were only negligible under experimental conditions. The overall balance of CH4, being consumed in OCM and formed in pyrolysis, was negative, equal to zero, or positive, depending on the relative contribution of the component processes. The integrated process could be based, therefore, either on CH4 and naphtha as raw materials or exclusively on naphtha, with the recirculation of the excess of CH4 to the OCM section. Copyright © 2004 Society of Chemical Industry
Stripping of Rh–Sn–Cl‐loaded alkylated 8‐hydroxyquiniline with Na2SO3–HCl
Authors: Benguerel Elyse , Demopoulos George P 
Published: February 2004

AbstractAcidic rhodium(III) chloride solutions pretreated with SnCl2 at a ratio Sn(II) : Rh(III) = 3 are contacted with an alkylated 8‐hydroxyquinoline (Kelex 100) to prepare loaded organics which subsequently are subjected to stripping with Na2SO3–HCl solutions. Rh(III) was found to be stripped selectively involving the following reaction:

where H2Q is the protonated form of kelex 100. Direct characterization of the stripped complex and slope analysis confirmed this stripping reaction. Equilibrium was reached within 20 min. A kinetic analysis found the stripping process to be irreversible and to be controlled most probably by the slow release of SnCl3− ligand from the intermediate Rh–Q–SO3–SnCl3 organic complex. Copyright © 2004 Society of Chemical Industry