bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of EGF receptor transactivation in phosphoinositide 3‐kinase‐dependent activation of MAP kinase by GPCRs
Authors: Shah Bukhtiar H. , Neithardt Adrienne , Chu David B. , Shah Farzana B. , Catt Kevin J. 
Published: May 2005

AbstractMany G protein coupled receptors (GPCRs) cause phosphorylation of MAP kinases through transactivation of the epidermal growth factor receptor (EGF‐R), leading to increased cell survival and growth, motility, and migration. Phosphoinositide 3‐kinase (PI3K) is one of the important cell survival signaling molecules activated by EGF‐R stimulation. However, the extent to which EGF‐R transactivation is essential for GPCR agonist‐stimulated PI3K activation is not known. Here we examined the mechanism of PI3K activation that elicits GPCR‐mediated ERK1/2 activation by pathways dependent and/or independent of EGF‐R transactivation in specific cell types. Immortalized hypothalamic neurons (GT1‐7 cells) express endogenous gonadotropin‐releasing hormone receptors (GnRH‐R) and their stimulation causes marked phosphorylation of ERK1/2 and Akt (Ser 473) through transactivation of the EGF‐R and recruitment of PI3K. In C9 hepatocytes, agonist activation of AT1 angiotensin II (AT1‐R), lysophosphatidic acid (LPA), and EGF receptors caused phosphorylation of Akt through activation of the EGF‐R in a PI3K‐dependent manner. However, ERK1/2 activation by these agonists in these cells was independent of PI3K activation. In contrast, agonist stimulation of HEK 293 cells stably expressing AT1‐R caused ERK1/2 phosphorylation that was independent of EGF‐R transactivation but required PI3K activation. LPA signaling in these cells showed partial and complete dependence on EGF‐R and PI3K, respectively. These data indicate that GPCR‐induced ERK1/2 phosphorylation is dependent or independent of PI3K in specific cell types, and that the involvement of PI3K during ERK1/2 activation is not dependent solely on agonist‐induced transactivation of the EGF‐R. Published 2005 Wiley‐Liss, Inc.
Involvement of axonal guidance proteins and their signaling partners in the developing mouse mammary gland
Authors: Morris Joanna S. , Stein Torsten , Pringle Marie‐Anne , Davies Claire R. , Weber‐Hall Stephen , Ferrier Roderick K. , Bell Alexandra K. , Heath Victoria J. , Gusterson Barry A. 
Published: May 2005

AbstractMammary morphogenesis in the mouse is driven by specialized structures at the ends of the developing ducts, the terminal end buds (TEB). The mechanisms controlling the precise branching and spacing of the ducts are, as yet, unknown. To identify genes that are associated with migration of TEB and differentiation of the subtending ducts, we developed a novel method of isolating TEB and ducts free of stroma, and compared the gene expression profiles of these two isolates using oligonucleotide microarrays. Ninety one genes were upregulated in TEB compared to ducts. Three of these genes,Sprr1A,Sema3B, andBASP1, are associated with axonal growth and guidance. Two additional members of the Sprr family, Sprr2A and 2B, not previously associated with axonal growth, were also highly expressed in TEB. Expression of these genes was confirmed by RT‐PCR and Western blotting, and the cellular distribution of Sprr1A and BASP1 was demonstrated by immunohistochemistry. Other semaphorins, including Sema3C, 4A, 4F and the cancer invasion associated Sema 4D were also expressed in the mouse mammary gland along with the semaphorin receptors, Plexins A2, A3, B2, and D1, and Neuropilins 1 and 2. These results are discussed in the context of other proteins expressed in the developing gland that are known to be downstream effectors of these signaling molecules. We suggest that these genes may influence ductal growth and morphogenesis in the developing mammary gland. © 2005 Wiley‐Liss, Inc.
Changes in secreted and cell associated proteoglycan synthesis during conversion of myoblasts to osteoblasts in response to bone morphogenetic protein‐2: Role of decorin in cell response to BMP‐2
Authors: Gutierrez Jaime , Osses Nelson , Brandan Enrique 
Published: May 2005

AbstractProteoglycans have been identified within the extracellular matrices (ECM) of bone and are known to play a role in ECM assembly, mineralization, and bone formation. Bone morphogenetic protein‐2 (BMP‐2) specifically converts the differentiation pathway of C2C12 myoblasts into that of osteoblast lineage cells. Microarray analyses of the mouse myoblast cell line C2C12 and its differentiation into osteoblastic cells in response to BMP‐2 have suggested the up‐regulation of several proteoglycan species, although there is a lack of biochemical evidence for this response. In this study we have biochemically analyzed and characterized the proteoglycan populations that are induced in C2C12 cells upon osteoblastic differentiation produced by BMP‐2. An important and specific increase in the synthesis of secreted decorin was observed in BMP‐2‐treated cells, as compared to untreated myoblasts and myoblasts induced to differentiate into myotubes. Decorin was seen to contain larger glycosaminoglycan (GAG) chains in induced than in non‐induced cells. BMP‐2 also produced an augment in the synthesis of different heparan sulfate proteoglycans such syndecan‐2, ‐ 3, glypican, and perlecan in detergent‐soluble and non‐soluble cellular fractions. We also examined whether the evident changes induced by BMP‐2 in secreted decorin could have a functional role. BMP‐2 signaling dependent as well as induction of alkaline phosphatase (ALP) activity was diminished in decorin null myoblasts compared to wild type myoblats although cell surface level of BPM‐2 receptors was unchanged. These results are the first biochemical evidence and analysis for the effect of BMP‐2 on the synthesis of proteoglycan during osteogenic conversion of myoblasts and suggest a role for decorin in cell response to BMP‐2. © 2005 Wiley‐Liss, Inc.
Loss of shear stress induces leukocyte‐mediated cytokine release and blood–brain barrier failure in dynamic in vitro blood–brain barrier model
Authors: Krizanac‐Bengez Ljiljana , Mayberg Marc R. , Cunningham Edwin , Hossain Mohammed , Ponnampalam Stephen , Parkinson Fiona E. , Janigro Damir 
Published: May 2005

AbstractBrain ischemia is associated with an acute release of pro‐inflammatory cytokines, notably TNF‐α and IL‐6 and failure of the blood–brain barrier. Shear stress, hypoxia‐hypoglycemia, and blood leukocytes play a significant role in blood–brain barrier failure during transient or permanent ischemia. However, these mechanisms have not been studied as independent variables for in vitro ischemia. The present study, using a dynamic in vitro blood–brain barrier model, showed that flow cessation/reperfusion under normoxia–normoglycemia or hypoxia–hypoglycemia without blood leukocytes in the luminal perfusate had a modest, transient effect on cytokine release and blood–brain barrier permeability. By contrast, exposure to normoxic–normoglycemic flow cessation/reperfusion with blood leukocytes in the luminal perfusate led to a significant increase in TNF‐α and IL‐6, accompanied by biphasic blood–brain barrier opening. Enhanced permeability was partially prevented with an anti‐TNF‐α antibody. In leukocyte‐free cartridges, the same levels of IL‐6 had no effect, while TNF‐α caused a moderate increase in blood–brain barrier permeability, suggesting that blood leukocytes are the prerequisite for cytokine release and blood–brain barrier failure during reduction or cessation of flow. These cells induce release of TNF‐α early after ischemia/reperfusion; TNF‐α triggers release of IL‐6, since blockade of TNF‐α prevents IL‐6 release, whereas blockade of IL‐6 induces TNF‐α release. Pre‐treatment of blood leukocytes with the cyclooxygenase (COX) inhibitor, ibuprofen, inhibited cytokine release and completely preserved blood–brain barrier permeability during the reperfusion period. In conclusion, loss of flow (flow cessation/reperfusion) independent of hypoxia–hypoglycemia plays a significant role in blood–brain barrier failure by stimulating leukocyte‐mediated inflammatory mechanisms. © 2005 Wiley‐Liss, Inc.
EEDA: A protein associated with an early stage of stratified epithelial differentiation
Authors: Sun Lijie , Ryan David G. , Zhou Mingyuan , Sun Tung‐Tien , Lavker Robert M. 
Published: May 2005

AbstractUsing suppressive subtractive hybridization, we have identified a novel gene, which we named early epithelial differentiation associated (EEDA), which is uniquely associated with an early stage of stratified epithelial differentiation. In epidermis, esophageal epithelium, and tongue epithelium, EEDA mRNA, and antigen was abundant in suprabasal cells, but was barely detectable in more differentiated cells. Consistent with the limbal location of corneal epithelial stem cells, EEDA was expressed in basal corneal epithelial cells that are out of the stem cell compartment, as well as the suprabasal corneal epithelial cells. The strongest EEDA expression occurred in suprabasal precortical cells of mouse, bovine, and human anagen follicles. Developmental studies showed that the appearance of EEDA in embryonic mouse epidermis (E 15.5) coincided with morphological keratinization. Interestingly, EEDA expression is turned off when epithelia were perturbed by wounding and by cultivation under both low and high Ca2+ conditions. Our results indicate that EEDA is involved in the early stages of normal epithelial differentiation, and that EEDA is important for the “normal” differentiation pathway in a wide range of stratified epithelia. © 2005 Wiley‐Liss, Inc.
Undesired components in the transformation of biomass pyrolysis oil into hydrocarbons on an HZSM‐5 zeolite catalyst
Authors: Gayubo Ana G , Aguayo Andrés T , Atutxa Alaitz , Valle Beatriz , Bilbao Javier 
Published: May 2005

AbstractThe results of the catalytic transformation on HZSM‐5 zeolite of mixtures of components of biomass pyrolysis oil in the 673–723 K temperature range are evidence of the need for previously separating certain components (aldehydes, oxyphenols and furfural) that undergo severe thermal degradation by forming carbonaceous deposits at the reactor inlet ducts and on the catalyst itself. The deactivation of the catalyst is a consequence of the deposition of two different types of coke: one of catalytic origin (similar to that generated in the transformation of methanol and bioethanol) and the other of thermal origin, which is produced by the aforementioned degradation. The remaining oxygenate components react to each other with synergistic effect, which means that their reactivity is higher than that of the pure components. The results show that the aqueous fraction of biomass pyrolysis oil may be transformed into hydrocarbons on acid catalysts similarly to the more familiar transformation of methanol and bioethanol. Copyright © 2005 Society of Chemical Industry
Optimization of volatile fatty acid compositions for hydrogen production by Rhodopseudomonas capsulata
Authors: Shi Xian‐Yang , Yu Han‐Qing 
Published: May 2005

AbstractThe effects of volatile fatty acid (VFA) compositions on the cell growth, H2 production rate and H2 yield have been investigated using mathematical models. The results show that a modified logistic model indicates that the maximum cell growth of 0.03 h−1 was obtained at acetate fraction of 0.571, propionate 0.143 and butyrate 0.286 in the total amount of VFA. The response surface methodology appears to be a useful approach to select appropriate substrate compositions for H2 production. Under the conditions in this work, the fractions of 0.551–0.566 for acetate, 0.204–0.211 for propionate, and 0.230–0.238 for butyrate were optimal for H2 production by Rhodopseudomonas capsulata. Copyright © 2005 Society of Chemical Industry
An attempt to compare the performance of bioscrubbers and biotrickling filters for degradation of ethyl acetate in gas streams
Authors: Koutinas Michalis , Peeva Ludmila G , Livingston Andrew G 
Published: May 2005

AbstractThis study presents a comparison of the efficiency of a bioscrubber and a biotrickling filter (BTF) for the removal of ethyl acetate (EA) vapour from a waste gas stream, under the same operating conditions. The maximum EA elimination capacity achieved in the bioscrubber was 550 g m−3 h−1 with removal efficiency higher than 96%. For higher EA loadings the bioscrubber was oxygen limited, which caused incomplete EA biodegradation. When pure oxygen was fed to the bioscrubber at a rate of 0.02 L min−1, the bioscrubber recovered and could treat higher EA loadings without any oxygen limitation. The BTF achieved EA elimination capacity of 600 g m−3 h−1 with removal efficiency higher than 97% and the dissolved oxygen concentration remained substantially higher than in the bioscrubber. However, severe channelling and blockage of the spray nozzle occurred due to the excessive biomass growth. Overall, the bioscrubber system was easier to operate and control than the BTF, while an enhancement of the oxygen mass transfer in the bioscrubber could potentially increase its performance by up to three times. Copyright © 2005 Society of Chemical Industry
Model‐based specific growth rate control for Pichia pastoris to improve recombinant protein production
Authors: Ren Haitao , Yuan Jingqi 
Published: May 2005

AbstractConstant specific growth rate control in the methanol growth phase was investigated for the fed‐batch cultivation of Pichia pastoris expressing recombinant human serum albumin (rHSA). The methanol feeding strategy was determined based on an earlier proposed macrokinetic model to maintain the specific growth rate at preset levels. The experimental results demonstrate that the control strategy of constant specific growth rate is more effective than that of constant feeding rate to maximize production. Furthermore, the most productive setpoint of the specific growth rate is found between 0.005 and 0.006 h−1, which yields protein concentrations higher than 5 g l−1 at 160 h. In addition, a setpoint of 0.008 h−1 is suggested as the upper limit for specific growth rate control for the given expression system. Copyright © 2005 Society of Chemical Industry
Expansion characteristics of an anaerobic fluidized bed reactor with internal biogas production
Authors: Wu Chun‐Sheng , Huang Ju‐Sheng , Gou Hong‐You 
Published: May 2005

AbstractMore realistic dynamic bed‐expansion experiments using a three‐phase anaerobic fluidized bed reactor (AFBR) with and without internal biogas production were conducted for the establishment of correlation equations for the mean volume ratio of wakes to bubbles (k). A predictive model was also developed for the expansion characteristics of the three‐phase AFBR with internal biogas production. The predicted bed‐expansion heights (HGLS) deviated by only ±10% from the experimental measurements for the three‐phase AFBR. According to the modeling results, if a three‐phase AFBR is loaded into a carrier with low specific gravity (dry density of carrier, ρmd = 1.37 g cm−3; wet density of carrier, ρmw = 1.57 g cm−3) and operated at a high superficial liquid velocity (ul = 4.0 cm s−1), the ratio of HGLS to HLS at a high superficial gas velocity (ug = 1.5 cm s−1) can reach as high as 271%. A higher fluidized‐bed height has a greater effect on the bed‐expansion behavior because of the decrease in liquid pressure (surrounding gas bubbles) along the fluidized‐bed height. From parametric sensitivity analyses, HGLS is most sensitive to the parameter reactor width (X), especially within a small ΔX/X0 range of ±10%; sensitive to ρmw, diameter of the carrier, ρmd and total mass of carrier and least sensitive to ul, biofilm thickness and ug. Copyright © 2005 Society of Chemical Industry
A review of catalytic approaches to waste minimization: case study—liquid‐phase catalytic treatment of chlorophenols
Authors: Keane Mark A 
Published: May 2005

AbstractEffective waste management must address waste reduction, reuse, recovery/recycle and, as the least progressive option, waste treatment. Catalysis can serve as an integral green processing tool, ensuring lower operating pressures/temperatures with a reduction in energy requirements while providing alternative cleaner synthesis routes and facilitating waste conversion to reusable material. The case study chosen to illustrate the role that catalysis has to play in waste minimization deals with the conversion of toxic chlorophenols in wastewater. The presence of chloro‐organic emissions is of increasing concern with mounting evidence of adverse ecological and public health impacts. A critical overview of the existing treatment technologies is provided with an analysis of the available literature on catalytic dechlorination. The efficacy of Pd/Al2O3 to promote the hydrogen‐mediated dechlorination of mono‐ and dichlorophenols is demonstrated, taking account of both the physical and chemical contributions in this three‐phase (solid catalyst and liquid/gaseous reactants) system. Hydrodechlorination activity and selectivity trends are discussed in terms of chloro‐isomer structure, the influence of temperature is discussed, the role of base (NaOH) addition is examined and the feasibility of catalyst reuse is addressed. Copyright © 2005 Society of Chemical Industry
Acid hydrolysis of commercial chitosans
Authors: Knill CJ , Kennedy JF , Mistry J , Miraftab M , Smart G , Groocock MR , Williams HJ 
Published: May 2005

AbstractCommercial chitosans were subjected to controlled acid hydrolysis and their degrees of deacetylation (DD), molecular size and rheological flow profiles determined (pre‐ and post‐hydrolysis) by 1H‐NMR spectroscopy, high‐performance size‐exclusion chromatography and rheometry, respectively. Hydrolysis resulted in DD increases between 4 and 11%. Unhydrolysed chitosans had Mw and Mn values in the ranges 700–1200 and 130–210 kDa, respectively. Chitosan with the smallest initial molecular size averages had the smallest averages after hydrolysis; however, a chitosan with an intermediate initial molecular size proved to be most resistant to hydrolysis. Molecular size trends were paralleled by zero shear viscosity (η0) measurements determined by application of the Williamson model to rheological flow profile data. Viscosity is obviously related to molecular size, but does not necessarily reflect relative ease of hydrolysis, since specific hydrolysis conditions affect structurally similar polysaccharides in different ways (in terms of rate of depolymerisation and de‐N‐acetylation, etc), which are not simply due to differences in molecular size profiles pre‐hydrolysis. Copyright © 2005 Society of Chemical Industry
The interaction between Cu, Pb, Zn and Ni in their biosorption onto polyurethane‐immobilised Sphagnum moss
Authors: Zhang Yue , Banks Charles 
Published: May 2005

AbstractThe uptake of Cu(II), Pb(II), Zn(II) and Ni(II) was investigated both individually and from mixed metal ion solutions using Sphagnum moss biomass immobilised in a polyurethane support. The data were evaluated using the Langmuir isotherm equation, and sorption capacities were calculated for different concentration ranges. It was concluded that care must be taken in presentation and interpretation of results when this modelling approach is applied at low concentrations. Repeated metal loading cycles also gave lower values for sorption capacity compared with the maximum potential value, due to equilibrium effects. The uptake capacity for the different metals on a weight basis was in the order lead > copper > zinc > nickel, but on a molar basis this changed to copper > lead > nickel > zinc. Sorption from a multi‐component metal system showed that lead and copper competed equally for binding sites and much more effectively than zinc and nickel. Equations were derived to predict the percentage effect on a given metal ion of other metals in a multi‐metal system based their behaviour in the relevant single and binary systems. Copyright © 2005 Society of Chemical Industry
Storage of biodegradable polymers by an enriched microbial community in a sequencing batch reactor operated at high organic load rate
Authors: Dionisi Davide , Beccari Mario , Di Gregorio Simona , Majone Mauro , Papini Marco Petrangeli , Vallini Giovanni 
Published: May 2005

AbstractThe production of polyhydroxyalkanoates (PHAs) from organic acids by mixed bacterial cultures using a process based on aerobic enrichment of activated sludge, that selects for mixed microbial cultures able to store PHAs at high rates and yields, is described. Enrichment resulted from the selective pressure established by periodic feeding the carbon source in a sequencing batch reactor (SBR); a mixture of acetic, lactic and propionic acids was fed at high frequency (2 hourly), high dilution rate (1 d−1), and at high organic load rate (12.75 g chemical oxygen demand (COD) L−1 d−1). The performance of the SBR was assessed by microbial biomass and PHA production as well as the composition and polymer content of the biomass. A final batch stage was used to increase the polymer concentration of the excess sludge produced in the SBR and in which the behaviour of the biomass was investigated by determining PHA production rates and yields. The microbial biomass selected in the SBR produced PHAs at high rate [278 mg PHAs (as COD) g biomass (as COD)−1 h−1, with a yield of 0.39 mg PHAs (as COD) mg removed substrates (as COD)−1], reaching a polymer content higher than 50% (on a COD basis). The stored polymer was the copolymer poly(3‐hydroxybutyrate/3‐hydroxyvalerate) [P(HB/HV)], with an HV fraction of 18% mol mol−1. The microbial community selected in the SBR was analysed by DGGE (denaturing gradient gel electrophoresis). The operating conditions of the SBR were shown to select for a restricted microbial population which appeared quite different in terms of composition with respect to the initial microbial cenosis in the activated sludge used as inoculum. On the basis of the sequencing of the major bands in the DGGE profiles, four main genera were identified: a Methylobacteriaceae bacterium, Flavobacterium sp, Candidatus Meganema perideroedes, and Thauera sp. The effects of nitrogen depletion (ie absence of growth) and pH variation were also investigated in the batch stage and compared with the SBR operative mode. Absence of growth did not stimulate higher PHA production, so indicating that the periodic feed regime fully exploited the storage potential of the enriched culture. Polymer production rates remained high between pH 6.5 and 9.5, whereas the HV content in the stored polymer strongly increased as the pH value increased. This study shows that polymer composition in the final batch stage can readily be controlled independently from the feed composition in the SBR. Copyright © 2005 Society of Chemical Industry
Use of ionic liquids as ‘green’ solvents for extractions
Authors: Zhao Hua , Xia Shuqian , Ma Peisheng 
Published: May 2005

AbstractThis review summarizes recent applications of ionic liquids (ILs) as ‘green’ solvents in extractions of a variety of substances, including metal ions, organic and bio‐molecules, organosulfur from fuels, and gases. ILs could also be used along with another ‘green’ technology, supercritical fluid extraction (SFE), for a more effective separation of products from ILs. In addition to their environmentally‐benign feature, ILs have other favorable properties over organic solvents used for extraction, such as adjustable hydrophobicity, polarity and selectivity. Copyright © 2005 Society of Chemical Industry
Evaluation of graphitized glass capillary columns
Authors: Goretti G. , Liberti A. , Pili G. 
Published: May 2005

AbstractThe performance of graphitized glass capillary columns obtained by precoating the inner glass walls with graphitized carbon black has been evaluated. It has been shown that according to the amount of stationary phase coated such columns can operate in gas–liquid‐solid chromatography and in gas–liquid chromatography so that tailor‐made columns for specific separations can be prepared. The versatility of these columns is shown in the separation of various mixtures (terpenes, pesticides, isomeric species and others) of analytical importance.