bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of p16INK4A variants in senescent human fibroblasts independent of protein phosphorylation
Authors: Weebadda Wineeta K.C. , Jackson Tonya J. , Lin Athena W. 
Published: January 2005

AbstractUpregulation of the p16 tumor suppressor is a hallmark of senescence in human fibroblasts. In this study, we investigated potential protein modification of p16 in senescent human fibroblasts using 2D SDS–PAGE analysis. Three distinct p16 variants with isoelectric points of 5.2, 5.4, and 5.6, were consistently detected in normal human IMR90 fibroblasts that had undergone senescence due to forced expression of oncogenic H‐ras or culture passage. Moreover, in contrast to short‐term serum starvation, which induces quiescence, IMR90 fibroblasts cultured in low serum for a prolonged period exhibited senescent phenotypes and expression of the three p16 variants. All three p16 variants are unlikely phosphoproteins since they failed to react with antibodies against phospho‐serine, and were resistant to the treatment with phosphatases. Functionally, co‐immunoprecipitation assays using antibodies against cdk4 and/or cdk6 revealed that only the two most acidic p16 variants associated with cdk4/6. Moreover, senescence induced by the forced expression of p16 in early passage IMR90 fibroblasts or osteosarcoma U2OS cells was accompanied by expression of the two most acidic p16 variants, which also associated with cdk4/6. In summary, we report that prolonged serum starvation‐induced senescence may provide an additional model for studying biochemical changes in senescence, including p16 regulation. Furthermore, induction of endogenous p16 in senescent human fibroblasts correlates with the expression of three distinct p16 variants independent of protein phosphorylation. Lastly, expression of the two cdk‐bound variants is sufficient to induce senescence in human cells. © 2004 Wiley‐Liss, Inc.
Passive osmotic properties of in situ human articular chondrocytes within non‐degenerate and degenerate cartilage
Authors: Bush Peter G. , Hall Andrew C. 
Published: January 2005

AbstractOsteoarthritis is characterized by many factors, including proteoglycan loss, decreased collagen stiffness, and increased cartilage hydration. Chondrocyte swelling also occurs, and correlates with the degree of osteoarthritis, however, the cause is unknown but might be related to alterations to their passive osmotic properties. We have used two‐photon confocal laser scanning microscopy to measure the passive osmotic characteristics of in situ chondrocytes within relatively non‐degenerate and degenerate human tibial plateau cartilage, and in chondrocytes isolated from relatively non‐degenerate cartilage. Explants with bone attached were taken from a total of 42 patients undergoing arthroplasty and graded macroscopically and microscopically into two groups, grade 0 + 1 and grade 2 + 3. There was a significant increase in cartilage hydration between these two groups (P < 0.05), however, there was no change when medium osmolarity was varied over ∼0–480 mOsm. The passive osmotic behavior of in situ chondrocytes (at 4°C) was identical over a range of culture medium osmolarities (∼0–515 mOsm), however, the maximum swelling of cells within degenerate cartilage and isolated chondrocytes was greater compared to those in non‐degenerate cartilage. The swelling in the majority of in situ chondrocytes was accounted for by the reduced interstitial osmolarity occurring with cartilage degeneration. There was, however, a small population of in situ chondrocytes whose volume was in excess (≥2,500 μm3) of that predicted from the decreased interstitial osmotic pressure. These results show that for the majority of cells studied, the differences in passive chondrocyte volume between relatively non‐degenerate, degenerate, and isolated cells were entirely accounted for by changes to the extracellular osmolarity (180–515 mOsm). © 2005 Wiley‐Liss, Inc.
Nitric oxide stimulated vascular smooth muscle cells undergo apoptosis induced in part by arachidonic acid derived eicosanoids
Authors: Pilane Cyril M. , LaBelle Edward F. 
Published: January 2005

AbstractThe role of eicosanoids in atherogenesis has not been thouroughly explained. This is partly due to the numerous eicosanoids and the variable effects that each has on different systems. Apoptosis of vascular smooth muscle cells has been shown to play a role in the atherosclerotic disease leading to lesion formation and further destabilization of the formed lesion. In this study, we have investigated the role of arachidonic acid derived eicosanoids in nitric oxide (NO)‐stimulated vascular smooth muscle cells. We have shown previously that the nitric oxide (NO)‐induced apoptosis of vascular smooth muscle cells was accompanied by arachidonic acid release via cytoplasmic phospholipase A2 (cPLA2) activation. Also, arachidonic acid, but not oleic acid, induced apoptosis of these cells at low concentrations (5–10 μM). Our results revealed that the cPLA2 specific inhibitor, arachidonyl trifluoromethyl ketone (AACOCF3), blocked NO‐induced eicosanoid production, while the presence of arachidonic acid enhanced the ability of the cells to make prostaglandin E2 (PGE2). Also, inhibitors of the cyclo‐oxygenase (Cox) enzymes, such as N‐[2‐cyclohexyloxy)‐4‐nitrophenyl]‐methanesulfonamide (NS‐398), a specific Cox‐2 inhibitor, or indomethacin, a non‐specific Cox inhibitor, blocked NO‐induced PGE2 production and apoptosis of vascular smooth muscle cells to the same extent, indicating that apoptosis might be induced by a Cox‐2 metabolic product. In addition to these observations, the eicosanoids investigated, namely, PGE2, PGI2 LTB4, and PGJ2, showed different effects on vascular smooth muscle cells. Both PGJ2 and LTB4 decreased the percentage of viable cells and induced apoptosis of vascular smooth muscle cells, while PGE2 and PGI2 had no effect on cell viability and failed to induce apoptosis. These data suggest that eicosanoids, such as PGJ2, but not PGE2 or PGI2, are involved in NO‐induced apoptosis of vascular smooth muscle cells and that the eicosanoid synthesis pathways might be utilized for vascular therapeutic strategies. © 2005 Wiley‐Liss, Inc.
Captopril and its synthesis from chiral intermediates
Authors: Chirumamilla R R , Marchant R , Nigam P 
Published: January 2005

AbstractCaptopril is an antihypertensive agent that inhibits the angiotensin‐converting enzyme of the renin–angiotensin system. Chiral intermediates are used in the synthesis of the drug. These intermediates are obtained by resolution of racemic compounds or by chemical, biocatalytic methods and or by asymmetric synthesis by biocatalytic process. This article reviews the various chemical and biochemical processes involved in the synthesis of the chiral drug, including the pharmacological action of captopril.© 2001 Society of Chemical Industry
Some catalytic properties of silica‐supported base and metal porphyrins for hydrocarbon cracking and hydrogenation
Authors: Caga I T , Carnell I D , Winterbottom J M 
Published: January 2005

AbstractA base porphyrin, etioporphyrin (EPI), has been synthesised and a number of metal–etioporphyrin compounds have been derived from EPI by metal insertion, these being nickel, vanadyl, palladium and platinum. The metal–etioporphyrins were supported on silica gel with loadings of 0.5–5.0% (w/w) to be employed as catalysts for hydrocarbon cracking and to a minor extent for hydrogenation. The porphyrins themselves were characterised using temperature programmed decomposition (TPD), temperature programmed reduction (TPR), mass spectroscopy (MS) and infra‐red (IR) spectroscopy. TPD studies up to 550 °C indicated complete stability and TPR studies (20–500 °C) showed interaction with hydrogen, nickel–EPI and Pd–EPI especially showing strong interaction. MS studies showed that metal insertion had occurred for VO–EPI and Ni–EPI and Pd insertion was demonstrated to have occurred using an analytical method. IR spectroscopy carried out on VO–EPI and Ni–EPI showed an absence of NH linkages, again confirming metal insertion. The behaviour of the catalysts for hydrocarbon cracking was studied using 2,2‐dimethylbutane (2,2‐DMB) as the model reactant in the temperature range 440–550 °C and thermally in the temperature range 440–600 °C and at 1 at, m (101.3 kPa) pressure. All porphyrins, even the base porphyrin, exhibited cracking activity and the catalysed reaction had an energy of activation, depending on the porphyrin, in the range 78–113 kJ/mol−1, compared with a value of 210 kJ mol−1 for the thermal reaction. The product distribution was dominated by C1 and C2 hydrocarbons and is typical of a free radical reaction, the thermal reaction giving a similar product distribution, so that the porphyrin catalyst acts as a free radical initiator. Hydrogenation studies using hex‐1‐ene at 150 °C and at 1 atm. pressure showed that Pd–EPI/SiO2 was an active and possibly stable hydrogenation catalyst, whereas Ni–EPI/SiO2 while of only slightly lower activity initially, lost that activity so that the Pd–EPI catalyst was over 16 times more active at the end of a 2 h period.© 2001 Society of Chemical Industry
Low energy steam explosion treatment of plant biomass
Authors: Sawada Tatsuro , Nakamura Yoshitoshi 
Published: January 2005

AbstractThe rational operational condition for maximizing the pretreatment effect on plant biomass while minimizing heat required was investigated. Eucalyptus globulus chips were used to evaluate the operational method for the most efficient conversion of plant biomass into useful materials by steam explosion. The energy consumption required to carry out the steam explosion was calculated by considering the mass balances of the water, the wood component, and the heat balance in the steam explosion apparatus. The energy consumption increased significantly with the increase of steam pressure and steaming time, and decreased rapidly with increase of the thickness of the heat‐insulating material in the steam explosion apparatus. The amount of methanol‐soluble lignin, a low molecular weight lignin, was measured experimentally under various operational conditions such as steam pressure and steaming time. The steam explosion at the steam pressure of 3.9 MPa and steaming time of 1.1 min was the most effective method for maximizing the delignification with low energy consumption.© 2001 Society of Chemical Industry
The preparation of D‐glucaric acid by oxidation of molasses in packed beds
Authors: Pamuk Vecihi , Yılmaz Murat , Alıcılar Ahmet 
Published: January 2005

AbstractAn attempt has been made to prepare glucaric acid by oxidation of sugar beet molasses in packed beds. In the first part, a suitable oxidizing medium was sought. Experiments were performed in a cylindrical Pyrex‐glass reactor with air–molasses cocurrent downflow. Spherical glass and cylindrical vanadium pentoxide particles were used as an inert packing and catalyst respectively. The addition of catalyst, sodium nitrite, nitric and sulfuric acids to the medium resulted in an improvement in glucaric acid yield. The presence of nitric acid in the oxidizing medium and the use of vanadium pentoxide catalyst were the most effective factors as regards the yield. In the second part, the effects of temperature, molasses concentration, amount of catalyst and air flow rate on the yield were studied; each of these variables increased the yield. The use of a longer catalyst bed, however, resulted in a decrease in the yield. The highest rate of conversion of glucose to glucaric acid was 63.9% at optimum conditions.© 2001 Society of Chemical Industry
Adsorption behaviour of metal ions on imprinted chitosan resin
Authors: Tianwei Tan , Xiaojing He , Weixia Du 
Published: January 2005

AbstractA new method for preparation of metal ion imprinted chitosan resin, which can considerably enhance the adsorption capacity and selectivity of the metal ion is presented in this paper. The conditions influencing the preparation of chitosan imprinted resin such as the cross‐linking agent, epichlororohydrin and ethylene glycol diglycidyl ether, and metal ion concentration are optimized. The chemical and the physical stability are also discussed and the imprinted chitosan resin can be used many times without losing adsorption capacity. The adsorption isotherms were studied and a new model was suggested to correlate the relationship of adsorption with pH and metal ion concentration.© 2001 Society of Chemical Industry
Oxidation of benzothiazole, 2‐mercaptobenzothiazole and 2‐hydroxybenzothiazole in aqueous solution by means of H2O2/UV or photoassisted Fenton systems
Authors: Andreozzi R , Caprio V , Marotta R 
Published: January 2005

AbstractOxidative treatments of benzothiazole and benzothiazole derivatives (2‐mercaptobenzothiazole, 2‐hydroxybenzothiazole) in aqueous solution have been studied by using H2O2/UV and iron(III) photoassisted Fenton techniques. Experimental runs have been carried out in the pH range 3.0 –8.0 by means of annular reactors and proper UV lamps. The effect of pH, the initial concentration of hydrogen peroxide, the substrate, and the iron(III) concentrations have been investigated. A suitable model has been developed and used for the best estimation of kinetic constants for HO radical attack on the target molecules with the H2O2/UV system. The values obtained with this model are consistent with those reported in the literature for other heterocyclic compounds.© 2001 Society of Chemical Industry
Growth‐promoting properties of yeast extracts produced at different pH values, with different autolysis promoters and bacterial populations
Authors: Barrette Julie , Champagne Claude P , Goulet Jacques 
Published: January 2005

AbstractThe effect of the autolysis conditions of bakers' yeast on the growth‐promoting properties of the resulting yeast extracts (YE) were examined on cultures of Lactococcus lactis ssp lactis D25 and of Lactococcus lactis ssp cremoris R2. The various YE were produced by conducting autolysis at four pH levels (pH 4.0, 5.5, 7.0 or 8.5) and with or without the autolysis promoters (AP) ethyl acetate or chitosan. To determine if the presence of contaminating bacteria during autolysis affected the YE characteristics, one series of YE was also prepared with the bakers' yeast cell suspension contaminated with 108 CFU/cm−3 of typical yeast plant bacteria (mostly of the Bacillus genus) at the beginning of autolysis. The growth curves of the lactococci in media supplemented with the various YE were analyzed to determine the maximum optical density (ODmax), the maximum growth rate (µmax) and the fermentation time (F‐time) at which ODmax was reached. The addition of bacterial contaminants (at 108 CFUcm−3) did not significantly influence the growth‐promoting properties of YE. The lactococci had higher ODmax and µmax values when the media contained YE produced at pH 4.0 or 5.5, and these YE contained 40% more total nitrogen than those obtained at pH 7.0 or 8.5. There was no major effect of AP on the biological value of the resulting YE, but a significant interaction between pH and AP was found for L lactis D25. Thus the ODmax of YE produced at pH 7.0 and 8.5 were highest when ethyl acetate was used as autolysis promoter, as compared with control and chitosan at pH 7.0–8.5, while the opposite was obtained with products produced at pH 4.0 and 5.5. This study shows that parameters used to produce YE influence their biological value with respect to the growth‐promoting properties of lactococci.© 2001 Society of Chemical Industry
The effect of fermentation parameters on the production of Mucor miehei acid protease in a chemically defined medium
Authors: Ayhan F , Çelebi Serdar S , Tanyolaç A 
Published: January 2005

AbstractBatch shake flask experiments were carried out with a fungal strain of Mucor miehei ATCC 3420 to study the effects of five fermentation parameters; initial D‐glucose concentration, temperature, initial pH, agitation rate and inoculum ratio, on the production of rennin in a chemically defined medium. A statistical design was used to assign the experimental levels of five fermentation parameters for the determination of optimum conditions. The highest concentration of milk‐clotting activity (MCA) obtained was 2286 SU cm−3 (without concentration of the broth) at 29.6 g dm−3 initial D‐glucose concentration, 6.8 initial pH, 37.6 °C temperature, 81 stroke per min agitation rate and 5.2% (v/v) inoculum ratio. Although enzyme secretion was a function of all the operational parameters investigated, the pH range (4.6–5.2) reached at the time of enzyme production had a profound effect on milk‐clotting activity levels. In the fermentation sample at maximum milk‐clotting activity the R factor, the ratio of milk‐clotting activity to proteolytic activity, was determined as 1 SU PU−1, denoting similar characteristics to a commercial animal rennet.© 2001 Society of Chemical Industry
Electrochemical removal of cadmium using a batch undivided reactor with a rotating cylinder electrode
Authors: Grau Javier M , Bisang José M 
Published: January 2005

AbstractThe performance of an undivided electrochemical batch reactor with a rotating cylinder electrode under potentiostatic control is examined for the removal of cadmium from a sodium sulfate solution containing 500 ppm Cd(II) at pH ≅ 7. The effect of hydrogen evolution as a side cathodic reaction on the figures of merit of the reactor is analysed. The best results were obtained for a cathode potential of −0.9 V against the saturated calomel electrode. With an angular velocity of 1500 rpm the space time yield and the normalized space velocity were 0.66 mol m−3 s−1 and 3.9 h−1 respectively, while the fractional conversion was 67.3% with a current efficiency of 66.7%. The surface morphology of the deposits as a function of the applied potential is also reported.© 2001 Society of Chemical Industry
Study of alternatives for the design of a mobile unit for wastewater treatment by supercritical water oxidation
Authors: Cocero M José , Sanz M Teresa , Fernández‐Polanco Fernando 
Published: January 2005

AbstractSupercritical water oxidation (SCWO) has been shown to be an appropriate technology for the treatment of water containing toxic and hazardous substances, because it provides high destruction efficiencies. This paper reports a study of alternatives, and optimisation of various parameters and conditions, which are applied to the design of a mobile treatment unit. Phenol was selected as a model organic compound present in the feed stream and NaCl was selected as a model polar compound for solid separation. Pilot plant results show that efficiencies above 99.9% in phenol destruction are reached, at an operation temperature of about 650 °C, with stoichiometric amounts of air. Feed streams with a wide range of heating values (lower limit 530 and upper limit 930 kJ kg−1) can be handled, because these values allow both thermal and mechanical energy recoveries, which are the key factor for economic feasibility. The unit is capable of handling wastewater containing toxic, recalcitrant or non‐biodegradable compounds that cannot be treated with global streams at the wastewater treatment plant of a factory. It is specifically proposed for use in industries in which wastewater contains solvent mixtures of fine chemicals and pharmaceuticals.© 2001 Society of Chemical Industry
Dynamic enzymatic resolution of Naproxen methyl ester in a membrane bioreactor
Authors: Xin Jia‐ying , Li Shu‐ben , Xu Yi , Chui Jun‐ru , Xia Chun‐gu 
Published: January 2005

AbstractA lipase‐catalyzed enantioselective continuous hydrolysis process under in situ racemization of substrate using sodium hydroxide as catalyst was developed for the production of (S)‐Naproxen from racemic Naproxen methyl ester in an aqueous–organic biphase system. Use of a tubular silicone rubber membrane in the stirred tank reactor to separate the chemical catalytic racemization and biocatalytic resolution processes, served to avoid the key problem associated with conventional dynamic resolution, viz the incompatibility of in situ chemical racemization with the presence of a biocatalyst. To overcome product inhibition and to facilitate product recovery from the aqueous–organic emulsion containing substrate and lipase, a hydrophilic porous semipermeable membrane was used in the stirred tank reactor. Greater than 60% conversion of the racemate with an enantiomeric excess of product (eep) greater than 96% was obtained. In addition, transformation of Candida rugosa lipase (CRL) isoenzymes was observed in the reaction process.© 2001 Society of Chemical Industry
Adsorption of selected toxic metals by modified peanut shells
Authors: Chamarthy Srinath , Seo Chung W , Marshall Wayne E 
Published: January 2005

AbstractThe objective of this study was to modify peanut shells to enhance their adsorptive properties toward the metal ions cadmium (Cd2+), copper (Cu2+), nickel (Ni2+), lead (Pb2+) and zinc (Zn2+). Milled peanut shells were initially washed with water or 0.1 N NaOH or left unwashed. Following these treatments or lack of treatment, the shells were either left unmodified or modified by a heat treatment in the presence of either 1.0 M phosphoric acid or 0.6 M citric acid. Modified peanut shells were evaluated either for adsorption efficiency or for adsorption capacity using the five metal ions listed above. Adsorption efficiencies and capacities were compared with efficiencies and/or capacities for the commercial chelating or cation exchange resins Amberlite 200, Amberlite IRC‐718, Duolite GT‐73, and carboxymethylcellulose. For the adsorption efficiencies of individual metal ions, modified peanut shells met or exceeded the adsorption values for cadmium, copper, nickel or zinc ions compared with the commercial resins Duolite GT‐73 and carboxymethylcellulose. In a solution containing all five metal ions, modified peanut shells met or exceeded the adsorption efficiencies for cadmium, copper and lead ions compared with Duolite GT‐73, Amberlite IRC‐718 and carboxymethylcellulose. Adsorption capacities of modified peanut shells met or exceeded the adsorption capacity of Duolite GT‐73 for lead ions only. Citric or phosphoric acid‐modified peanut shells showed a preference for Cu2+ and Pb2+ and appear promising as potentially inexpensive adsorbents for selected metal ions.© 2001 Society of Chemical Industry
The effect of recycle ratio on nitrogen removal in the combined pre‐denitrification/nitrification biofilter system
Authors: Chiou Ren‐Jie , Ouyang Chaio‐Fuei 
Published: January 2005

AbstractPrevious research has shown that nitrogen in municipal wastewater could be eliminated by a biofilter system. This study investigates the effect of the recycle ratio on total nitrogen removal and the nitrogen component in the effluent. In this study, a system combining pre‐denitrification/nitrification biofilters was set up. The experiments which varied the recycle ratio of the nitrifying solution to the influent were carried out in order to determine the amount of the total nitrogen removal and the form of nitrogen in the effluent. These experimental results show that total nitrogen removal might be dependent on nitrification but not on denitrification. Although the operation at a low recycle ratio would result in a lower value of total nitrogen removal, the NH3‐N content of the effluent would be lower and the flow condition would be more stable. In comparison, operation at a higher recycle ratio would result in a lower NO3−‐N content in the effluent, while the NH3‐N content in the effluent would be higher. At a recycle ratio of 2.5, the total nitrogen removal is at its maximum. The relationship between specific nitrification rate and recycle ratio is also discussed.© 2001 Society of Chemical Industry