bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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

Several 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

The 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

The 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

The 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

The 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

A 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

Acidic 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
Treatment of gully pot effluent containing nickel and copper with constructed wetlands in a cold climate
Authors: Scholz Miklas
Published: February 2004

The aim of this study was to assess the treatment efficiencies for gully pot effluent of experimental vertical‐flow constructed wetland filters containing macrophytes and granular media of different adsorption capacities in a cold climate. For approximately 6 months, nickel nitrate and copper nitrate were added to sieved gully pot effluent in order to simulate contaminated primary treated stormwater runoff. The inflow concentrations for nickel, copper and nitrate were approximately 1.0, 1.0 and 3.7 mg dm−3, respectively. For those filters receiving metals, an obvious breakthrough of nickel was recorded after road gritting (containing salt). Reductions of nickel, copper, biochemical oxygen demand and suspended solids were frequently insufficient compared with international secondary wastewater treatment standards (eg suspended solids <30 mg dm−3). A further treatment step should be considered. Outflow conductivity and nickel concentrations were high due to the effect of road salting. Microbial activity was likely to be responsible for the overall filtration performance. Copyright © 2003 Society of Chemical Industry
Biological oxidation of ferrous iron: study of bioreactor efficiency
Authors: Mesa MM , Andrades JA , Macías M , Cantero D
Published: February 2004

The bio‐oxidation of ferrous iron is a potential industrial process for the regeneration of ferric iron in the removal of H2S. In the first stage, H2S is selectively oxidized to elemental sulfur using ferric sulfate. The ferrous sulfate produced is oxidized to ferric sulfate using Thiobacillus ferrooxidans for recycle and reuse in the process. The aim of the work described here was to investigate continuous oxidation of ferrous iron by immobilized T ferrooxidans and the factors which can directly affect the oxidation rate in order to assess the feasibility of this technique on an industrial scale. An analysis of the evolution of bioreactor performance with time (125 days) was performed in order to assess the feasibility of this technique on an industrial scale. A good oxidation rate was obtained despite the transport problems encountered due to occlusion of the porous support. On the other hand, the toxic effects due to absorption in the ferric solution of one or more compounds from the gas digester were studied using a ferric iron solution from the absorption process. The results indicate the feasibility of the biological system for the regeneration of the ferric‐absorbing solution. Finally, a previous study for the design of an industrial bioreactor to regenerate ferric sulfate solutions, used to remove H2S from biogas in a wastewater‐treatment plant (Jerez de la Frontera, Spain), is introduced. Good biological oxidation performances have been obtained using a pilot plant bioreactor of 500 dm3. Copyright © 2003 Society of Chemical Industry
Effects of cationic polymer on start‐up and granulation in upflow anaerobic sludge blanket reactors
Authors: Wang Ying , Show Kuan‐Yeow , Tay Joo‐Hwa , Sim Kwee‐Hock
Published: February 2004

The upflow anaerobic sludge blanket (UASB) has been used successfully to treat a variety of industrial wastewaters. It offers a high degree of organics removal, low sludge production and low energy consumption, along with energy production in the form of biogas. However, two major drawbacks are its long start‐up period and deficiency of active biogranules for proper functioning of the process. In this study, the influence of a coagulant polymer on start‐up, sludge granulation and the associated reactor performance was evaluated in four laboratory‐scale UASB reactors. A control reactor (R1) was operated without added polymer, while the other three reactors, designated R2, R3 and R4, were operated with polymer concentrations of 5 mg dm−3, 10 mg dm−3 and 20 mg dm−3, respectively. Adding the polymer at a concentration of 20 mg dm−3 markedly reduced the start‐up time. The time required to reach stable treatment at an organic loading rate (OLR) of 4.8 g COD dm−3 d−1 was reduced by more than 36% (R4) as compared with both R1 and R3, and by 46% as compared with R2. R4 was able to handle an OLR of 16 g COD dm−3 d−1 after 93 days of operation, while R1, R2 and R3 achieved the same loading rate only after 116, 116 and 109 days respectively. Compared with the control reactor, the start‐up time of R4 was shortened by about 20% at this OLR. Granule characterization indicated that the granules developed in R4 with 20 mg dm−3 polymer exhibited the best settleability and methanogenic activity at all OLRs. The organic loading capacities of the reactors were also increased by the addition of polymer. The maximum organic loading of the control reactor (R1) without added polymer was 19.2 g COD dm−3 d−1, while the three polymer‐assisted reactors attained a marked increase in organic loading of 25.6 g COD dm−3 d−1. Adding the cationic polymer could result in shortening of start‐up time and enhancement of granulation, which may in turn lead to improvement in the efficiency of organics removal and loading capacity of the UASB system. Copyright © 2004 Society of Chemical Industry
Diffusion of glutamic acid in relation to growth of Geotrichum candidum and Penicillium camembertii at the surface of a solid medium
Authors: Stephan Johan , Couriol Catherine , Fourcade Florence , Amrane Abdeltif , Prigent Yves
Published: February 2004

Growth of pure cultures of Geotrichum candidum or Penicillium camembertii at the surface of a solid medium was studied. Consumption of nutrients by the microorganisms growing at the surface of the gel induced their diffusion from the core to the rind. Particular attention was paid to the diffusion of glutamic acid, the nitrogen source, in relation to the growth of the microorganism at the surface. The growth kinetic has been described using the Verlhust model. The diffusion coefficient of glutamic acid in sterile culture medium was measured and found to be 0.55 cm2 day−1. With this coefficient and assuming that the glutamic acid consumption was partially linked to growth, the experimental diffusion gradients have been fitted. Good agreement was found between experimental data and the diffusion/reaction model. The glutamic acid diffusion cannot be assumed to limit growth, since noticeable amounts of this substrate always remained at the upper surface of the gel. Copyright © 2004 Society of Chemical Industry
Production of fructooligosaccharides by β‐fructofuranosidase from Aspergillus sp 27H
Authors: Fernández Rubén Cuervo , Maresma Beatriz Guilarte , Juárez Antonio , Martínez Josefina
Published: February 2004

β‐fructofuranosidase (EC 3.2.1.26) from Aspergillus sp 27H isolated from soil was investigated for production of fructooligosaccharides (FOS) using whole cells. It possesses hydrolytic and transfructosylating activities that can be altered by modifying the reaction conditions. The optimal conditions for the transfructosylating activity occur in the pH range 5.5–6.0 and at 60 °C, while hydrolytic activity was highest at pH 4.0 and 55 °C. At low sucrose concentration (10 g dm−3) there was rapid conversion of sucrose to glucose and fructose and very low concentrations of FOS were obtained. However, at sucrose concentrations higher than 216 g dm−3 the concentrations of hydrolysis products were reduced. Under the following conditions: pH 5.5, temperature 40 °C, sucrose concentration 615 g dm−3 and enzyme concentration 20β‐fructofuranosidase units g−1 of sucrose, the FOS concentration reached a maximum value of 376 g dm−3 (234 g dm−3 1‐kestose and 142 g dm−3 nystose) and the proportion of FOS in the solids in the reaction mixture was 600–620 g kg−1 at 6 h. These results suggest that β‐fructofuranosidase from Aspergillus sp 27H could be an appropriate enzyme for the commercial production of FOS. Copyright © 2004 Society of Chemical Industry
The membrane emulsification process—a review
Authors: Charcosset C , Limayem I , Fessi H
Published: February 2004

Membrane emulsification has received increasing attention over the last 10 years, with potential applications in many fields. In the membrane emulsification process, a liquid phase is pressed through the membrane pores to form droplets at the permeate side of a membrane; the droplets are then carried away by a continuous phase flowing across the membrane surface. Under specific conditions, monodispersed emulsions can be produced using this technique. The purpose of the present paper is to provide a review on the membrane emulsification process including: principles of membrane emulsification, influence of process parameters and industrial applications. Small‐scale applications such as drug delivery systems, food emulsions, and the production of monodispersed microspheres are also included. Compared with conventional techniques for emulsification, membrane processes offer advantages such as control of average droplet diameter by average membrane pore size and lower energy input. Copyright © 2004 Society of Chemical Industry
Combined fermentation and evaporation processes for treatment of washwaters from Spanish‐style green olive processing
Authors: Brenes Manuel , Romero Concepción , de Castro Antonio
Published: February 2004

Washwaters from Spanish‐style green olive processing were fermented on a pilot plant scale (500 dm3) and evaporated under vacuum. Simultaneous or sequential inoculation in alkaline conditions with Enterococcus casseliflavus cc45 and Lactobacillus pentosus LP99 did not prevent malodorous spoilage. By contrast, appropriate fermentation was achieved when the washwaters were acidified with HCl, to pH 5, followed by inoculation with L pentosus, or acidified up to pH 3.4 with no subsequent inoculation. The type of fermentation influenced, to a large extent, the chemical oxygen demand (COD) of the distillate streams obtained when the washwaters were evaporated under vacuum. The high amount of ethanol formed in the washwaters, fermented only by yeasts, gave rise to distillates containing c 30% of the COD originally present in the washwaters, whereas this figure was 10% for washwaters fermented by lactobacilli. This work also disclosed the presence of large amounts of valuable substances, such as lactic acid and hydroxytyrosol in the concentrates, the latter compound being considered a very strong antioxidant with beneficial properties for human health. Copyright © 2004 Society of Chemical Industry
Influence of top‐section design and draft‐tube height on the performance of airlift bioreactors containing water‐in‐oil microemulsion
Authors: Mehrnia Mohammad Reza , Towfighi Jafar , Bonakdarpour Babak , Akbarnegad Mohammad Mehdi
Published: February 2004

The mixing and mass transfer characteristics of draft‐tube airlift bioreactors (DTAB) for a water‐in‐kerosene microemulsion, as a cold model of petroleum biodesulfurization, were studied. Incomplete gas disengagement at the top‐section of the DTAB and hence high gas recirculation were obtained with the microemulsion system for all the top‐section configurations employed in the present study especially at the high airflow rates. The ratio (S) of the volumes of the riser and the downcomer to the top‐section together with the gas disengagement abilities of the gas separator were both found to affect the mixing performance of the DTAB employed for the microemulsion system. Increase in the draft‐tube height resulted in significant increase in the mixing time (tm) and a slight increase in the overall volumetric oxygen transfer coefficient (kLa). Increase in the diameter of the top‐section and the height of the liquid above the draft‐tube led to a decrease in kLa, the latter effect being less prominent. New correlations were developed that predicted the mixing time and oxygen transfer coefficients obtained in the present work with reasonable accuracy. Copyright © 2004 Society of Chemical Industry
Enzymatic kinetics for lipase‐catalyzed hydrolysis of water‐insoluble substrate in AOT reverse micelles, involving native and activated lipases
Authors: Talukder MMR , Zaman MM , Hayashi Y , Wu JC , Kawanishi T , Ogino C , Shimizu N
Published: February 2004

The addition of short chain polyethylene glycols (PEGs) activated Chromobacterium viscosum lipase in AOT reverse micelles. In this study, it was assumed that when AOT reverse micelles contained PEG molecules, native and activated lipases contributed to the reaction according to their weight fraction in the system. The fractions of individual lipases and their specific activities were estimated by using kinetics parameters determined by previous kinetic models. The maximum specific activity of PEG‐activated lipase appeared to be 2.7 times higher than that of native lipase. The predicted weighted‐average activity agreed well with experimental data. The results showed that the previous kinetic models could be used to estimate the fraction of lipase activated by PEG molecules and their specific activity. Copyright © 2004 Society of Chemical Industry
Screening of supports for the immobilization of pectinmethylesterase from acerola (Malpighia glabra L)
Authors: de Assis Sandra Aparecida , Fernandes Pedro , Ferreira Bruno Sommer , Cabral Joaquim MS , Faria Oliveira Olga Maria Mascarenhas
Published: February 2004

A partially purified extract of pectinmethylesterase (PME) from acerola fruit was immobilized on various supports: glass, celite, chrysotile, agarose, concanavalin A Sepharose 4B, egg shell, polyacrylamide and gelatin. In addition, reticulation with glutaraldehyde was assessed, as well as the use of gelatin in the presence of celite, glass and silica. The highest immobilization yields were obtained when the pectinmethylesterase was immobilized in concanavalin A Sepharose 4B (81.7%) and in gelatin‐water (78.0%). Copyright © 2004 Society of Chemical Industry
Glucose production by hydrolysis of starch under hydrothermal conditions
Authors: Nagamori Makiko , Funazukuri Toshitaka
Published: February 2004

Starch was converted into glucose by hydrolysis with water under hydrothermal conditions at 453–513 K in a small batch reactor. The major product was glucose; oligomers having various degrees of polymerization, maltose, fructose, 5‐hydroxymethylfurfural and furfural were also produced. The maximum yield of glucose obtained was 630 g kg−1 on the carbon basis at 473 K and 30 min, where the quantity of carbon unrecovered was about 50 g kg−1, and the production of char and gaseous products was negligible. Copyright © 2004 Society of Chemical Industry
Removal of sodium dodecyl benzene sulfonate and phenol from water by a combined PAC adsorption and cross‐flow microfiltration process
Authors: Juang Ruey‐Shin , Lee Wen‐Cheng , Chen Ching‐Liang
Published: February 2004

The removal of sodium dodecyl benzene sulfonate (SDBS) and phenol from water by a combined process of PAC (powdered activated carbon) adsorption and cross‐flow microfiltration (PAC–MF) was investigated. Batch PAC adsorption studies were made to obtain the isotherm data. The PAC–MF experiments were performed as a function of PAC dose (0.2–1.0 g dm−3), solution pH (2.5–11.2), transmembrane pressure (10–30 psi), and cross‐flow velocity (4.7–8.3 mm s−1). A compromise between removal efficiency of the organics and the permeate flux in the PAC–MF process was needed to select a suitable PAC dose. The role of pH in the PAC–MF process mainly depended on the acid–base nature of the organics being removed. A comparison of PAC–MF and fixed bed processes was also made, and the application potential of this PAC–MF process for continuous removal of relatively high‐molar‐mass organics such as SDBS from waste effluents was demonstrated. Copyright © 2004 Society of Chemical Industry
Electrolytic removal of ammonia from brine wastewater: scale‐up, operation and pilot‐scale evaluation
Authors: Alfafara Catalino G , Kawamori Takayuki , Nomura Nakao , Kiuchi Masayuki , Matsumura Masatoshi
Published: February 2004

Brine wastewater with a high ammonia content from an iodine processing plant (commonly called kansui in Japan) was treated by electrolysis. The system, which can be considered as an indirect electrolytic treatment process, generates chlorine at the anodes and initiates the formation of mixed oxidants like hypochlorous acid. The oxidants then act as agents for ammonia destruction. Laboratory‐scale experiments showed that high ammonia concentrations (as much as 200 mg dm−3) could be completely removed within a few minutes, and could be considered a good alternative for efficient ammonia removal from saline wastewaters. From laboratory‐scale experiments in the batch and continuous modes, the charge dose was analyzed and used as the operating and scale‐up factor. The value of the charge dose was not severely affected by changes in operating conditions such as electrode spacing and temperature. The charge dose from batch and continuous runs was found to be in the range of 23 C (mg NH4‐N removed)−1 to 29 C (mg NH4‐N removed)−1. Using the charge dose obtained from laboratory‐scale continuous electrolysis experiments as the scale‐up factor, a pilot‐scale reactor was designed, and the operating conditions were calculated. In the pilot‐scale reactor tests at different flow rates, the effluent ammonia concentrations were reasonably close to the calculated values predicted from the charge dose equation. Copyright © 2004 Society of Chemical Industry
Copper(II) extraction by 4‐chloro‐N‐8‐quinolinylbenzenesulfonamide dissolved in toluene
Authors: Almela Ana , Huebra Marta , Elizalde María P , Menoyo Begoña
Published: February 2004

4‐Chloro‐N‐8‐quinolinylbenzenesulfonamide (HL) was synthesised and characterised by elemental analysis, IR and FT‐Raman spectroscopy. The synthesised reagent dissolved in toluene was used for copper(II) extraction from 1.0 mol dm−3 KNO3. The experimental extraction data have been treated graphically and numerically and the complexes CuL2 and Cu(NO3)L have been proposed as being responsible for the metal extraction. Values of the corresponding stoichiometric extraction constants have been determined. Copyright © 2004 Society of Chemical Industry
Improved extraction of penicillin G using hydrocarbon sulfoxides
Authors: Lei Wen , Li Zhou
Published: February 2004

Extraction of penicillin G with sulfoxide extractants, petroleum sulfoxide (PSO) and di‐isooctyl sulfoxide (DISO) was researched systematically. Based on research of the extraction equilibrium of penicillin G, the suitable extraction and re‐extraction conditions were determined, and then extraction cascade and bench‐scale experiments were carried out. The performance of extraction systems composed of PSO and DISO, with sulfonated kerosene as the diluent, is superior to that of n‐butyl acetate owing to the low solubility of these new extractants in water. Their consumption during the extraction process was lower, and the recovery step of extractants from aqueous raffinate was eliminated. Copyright © 2004 Society of Chemical Industry
Solvent extraction of silver by LIX® 79: experimental equilibrium study
Authors: Sastre Ana María , Kumar Anil , Alguacil Francisco José
Published: February 2004

The extraction of silver(I) from argentocyanide aqueous cyanide solutions using LIX® 79 has been studied. Different variables that could affect the extraction system were evaluated: equilibration time, aqueous pH, metal and extractant concentrations, and organic phase diluent. The extraction of the Ag(CN)2− complex with respect to other metal‐cyano complexes has also been studied on both synthetic and real leach solutions. Experimental data relating to silver have been analysed numerically to determine the stoichiometry of the extracted species and its equilibrium constant. It was found that silver(I) was extracted into the organic phase by the formation of the species RHAg(CN)2 (LIX 79 = R). Copyright © 2004 Society of Chemical Industry
Synthesis of Mo–W carbide via propane carburization of the precursor sulfide: Kinetic analysis
Authors: Nguyen Tuan‐Huy , Adesina Adesoji A , Yue Ernest MT , Lee Yong‐Joon , Khodakov Andrei , Brungs Michael P
Published: February 2004

Thermogravimetric analysis (TGA) has been used to investigate the carburization kinetics of Mo–W sulfide using an H2:C3H8 feed mixture. The effect of heating rate over the range 1–10 K min−1 showed that up to four different carburized products may be formed but the critical (peak) temperature for formation of these species and the amount (peak height) of each species formed are highly dependent on the heating rate employed. The critical temperature increased linearly with heating rate for each of the four products. The four TGA peaks corresponding to the four phase transformation species are consistent with XRD identifiable species, namely; α‐Mo2C, β‐Mo2C, W and MoC1−x. Isothermal conversion–time data at three different temperatures are described by a reaction‐controlled shrinking core model implicating a first‐order dependency on the H2:C3H8 ratio. The reaction exhibited fractional order dependence on the metal sulfide concentration, the associated global activation energy estimated as 227 kJ mol−1 is representative of a non‐catalytic gas–solid reaction. Copyright © 2004 Society of Chemical Industry
Non‐physiological overexpression of the low density lipoprotein receptor (LDLr) gene in the liver induces pathological intracellular lipid and cholesterol storage
Authors: Cichon Guenter , Willnow Thomas , Herwig Susanne , Uckert Wolfgang , Löser Peter , Schmidt Hartmut H. , Benhidjeb Tahar , Schlag Peter M. , Schnieders Frank , Niedzielska Dagmara , Heeren Joerg
Published: February 2004

Background

Gene therapy of familial hypercholesterolemia (FH) requires successful transfer and lifelong expression of a functional low density lipoprotein receptor (LDLr) gene in the liver. Most of the vector systems currently employed for gene therapy use promoter elements which do not modulate transgene expression in a physiological manner.

Methods

To study the in vivo effects of constitutive LDLr gene expression in the absence of interfering immunological reactions we established a new mouse model which combines homozygous LDLr deficiency and severe combined immune deficiency (SCID).

Results

Adenovirus‐mediated transfer and expression of the LDLr gene under the control of a commonly used virus‐derived promoter (minimal CMV promoter) leads to prolonged reduction of serum cholesterol levels in LDLr‐deficient SCID mice. During the first 10 days after gene therapy serum cholesterol drops to about 10% of pretherapeutic values. Serum cholesterol persists on this level for 2 weeks and then slowly starts to rise again. Four months after vector application serum levels have reached about 40% of pretherapeutic values. However, as early as 5 days after gene transfer, the histological analysis of liver sections revealed the formation of crystalline lipid/cholesterol deposits in the cytosol of hepatocytes. During the following 8 weeks the amount of crystals increased in size and density. The intracellular storage of lipid and cholesterol reduced cell viability and induced an accelerated loss of therapeutic DNA from mice livers as was shown in a comparative expression study employing a transgene with a different metabolic function (human alpha 1‐antitrypsin).

Conclusions

The non‐physiological constitutive overexpression of an LDL receptor gene induces an imbalance between the speed of LDL uptake and metabolism which leads to pathological accumulation of lipids and cholesterol in hepatocytes. To protect cells from negative effects of LDLr overexpression, future vector design should consider the use of physiologically controlled expression elements. Copyright © 2004 John Wiley & Sons, Ltd.
Cardiomyocyte hyperplasia after plasmid‐mediated vascular endothelial growth factor gene transfer in pigs with chronic myocardial ischemia
Authors: Laguens Rubén , Cabeza Meckert Patricia , Vera Janavel Gustavo , De Lorenzi Andrea , Lascano Elena , Negroni Jorge , del Valle Héctor , Cuniberti Luis , Martínez Verónica , Dulbecco Eduardo , Melo Carlos , Fernández Nahuel , Criscuolo Marcelo , Crottogini Alberto
Published: February 2004

Background

For over 40 years it has been proposed that cardiomyocyte hyperplasia may occur in hypertrophic human hearts. While this implies that heart myocytes can undergo cytokinesis, evidence of conventional cell division has been exceptionally reported. Recently, we found that gene transfer of vascular endothelial growth factor (VEGF) displays a mitogenic effect on adult cardiomyocytes. In the present study we searched for cardiomyocyte hyperplasia as evidence of VEGF‐induced cardiomyocyte cytokinesis.

Methods

Three weeks after implanting an Ameroid constrictor at the origin of the left circumflex artery, 16 pigs were randomized to receive 10 direct intramyocardial injections of 3.8 mg of plasmid encoding for VEGF (pVEGF) or empty plasmid. Five weeks later, hearts were weighed, myocyte diameter was measured in tissue sections, and myocyte length and nuclei number were studied in isolated myocytes. A resting echocardiogram was performed immediately before reoperation and before sacrifice to evaluate global and regional left ventricular function. Investigators were blinded to the study groups and nature of the injectate until the end of data analysis.

Results

No heart weight differences existed between groups. However, in the ischemic myocardium, pVEGF‐treated hearts had 22% more cardiomyocytes per unit volume and exhibited significantly more oligonucleated (1 or 2 nuclei) cardiomyocytes than hearts receiving empty plasmid.

Conclusions

In pigs with chronic myocardial ischemia, VEGF gene transfer induced cardiomyocyte cytokinesis, as revealed by cardiomyocyte hyperplasia. Our finding extends the previously reported mitogenic effect of VEGF on adult cardiomyocytes and supports the hypothesis that VEGF may have a therapeutic role in diseases characterized by myocardial cell loss. Copyright © 2004 John Wiley & Sons, Ltd.
Reducing mobilization of simian immunodeficiency virus based vectors by primer complementation
Authors: Grunwald Thomas , Pedersen Finn Skou , Wagner Ralf , Überla Klaus
Published: February 2004

Background

Human gene therapy vectors based on primate lentiviruses harbour in contrast to oncoretroviruses the risk of vector mobilization by human immunodeficiency viruses (HIV). Infection of cells transduced with a lentiviral vector by HIV could lead to packaging of the lentiviral vector RNA into HIV particles and transfer of the vector.

Methods

A new approach based on primer complementation was developed to reduce the risk of vector mobilization. The primer binding site (PBS) of an SIV‐based vector was mutated abolishing tRNA primer binding and thus blocking reverse transcription. This block was efficiently by‐passed during vector production by providing an artificial tRNA matching the mutated PBS with titers reaching 106 infectious units/ml.

Results

Primer‐complemented SIV vectors were mobilized from transduced cells by HIV‐1 >150‐fold less efficiently than vectors with wild‐type PBS. Mobilization of the primer‐complemented SIV vector by SIV was inhibited to a lesser extent indicating reduced efficacy of the primer complementation approach for preventing mobilization of lentiviral vectors by homologous virus. The analysis of the PBS of the vector DNA in target cells transduced with vectors containing mutated PBS in the absence of a matched tRNA suggests that formation of heterozygous particles followed by priming on the helper RNA and strand switch during reverse transcription can lead to mobilization of the primer‐complemented vector by SIV, but not HIV‐1. Although self‐inactivating vectors were more efficient in preventing vector mobilization by HIV‐1 than primer‐complemented vectors, mobilization remained undectable only if both approaches were combined.

Conclusions

The primer complementation approach should further reduce the risk of mobilization of self‐inactivating SIV‐based vectors by HIV‐1 and thus increase their safety. Copyright © 2004 John Wiley & Sons, Ltd.
Ex vivo gene transfer to mature skeletal muscle by using adenovirus helper cells
Authors: Kimura Shigemi , Ikezawa Makoto , Cao Baohong , Kanda Yasunari , Pruchnic Ryan , Cummins James , Huard Johnny , Miike Teruhisa , Suzuki Satoru
Published: February 2004

Background

Adenoviral gene transfer to adult skeletal muscle is hindered by several major limitations, including host immune responses and maturation‐dependent loss of myofiber infectivity. Ex vivo gene delivery is more efficient than direct viral injection in surmounting maturation‐dependent adenoviral transduction. Here we investigated the use of helper cells to improve the efficiency of ex vivo gene transfer to adult mouse skeletal muscle.

Methods

New producer cells carrying the E1 gene of adenovirus type 5 (E32 cells) were developed using primary myoblasts from mdx mice. The E32 cells and 293 cells were infected with an E1‐deleted first‐generation adenovirus carrying the LacZ gene. These transduced helper cells were injected into the skeletal muscle of adult mdx and SCID mice.

Results

LacZ‐positive mature myofibers were detected in the skeletal muscle of adult mice sacrificed 5 days post‐injection. The gene transfer efficiency using 293 cells and E32 cells was 6.2 and 3.6 times higher than myoblast‐mediated gene transfer, respectively. Ex vivo gene transfer of these cell types led to a better outcome than did direct adenoviral injection.

Conclusions

We achieved more efficient adenoviral gene transduction by using 293 and E32 helper cells than by myoblast‐mediated gene transfer and direct viral injection. These helper cells also enabled adenoviral gene transfer to mature myofibers. The mechanisms by which this method facilitated adenoviral gene transfer to mature myofibers remains unclear; however, we hypothesize that the in vivo occurrence of cytopathic effects (CPE) in the transduced 293 and E32 helper cell populations facilitated the improved adenoviral transduction of myofibers. Copyright © 2004 John Wiley & Sons, Ltd.
In vitro and in vivo delivery of intact BAC DNA – comparison of different methods
Authors: Magin‐Lachmann C. , Kotzamanis G. , D'Aiuto L. , Cooke H. , Huxley C. , Wagner E.
Published: February 2004

Background

The ability to deliver large (>100 kb) fragments of DNA to mammalian cells in vitro and in vivo is becoming increasingly important with the availability of BAC and PAC constructs for gene expression. Here we investigate in vitro and in vivo delivery of BACs up to 157 kb.

Methods

Different types of polyethylenimine (PEI) and Lipofectamine were used to deliver 150‐kb BAC (bacterial artificial chromosome) DNA to mouse and human cell lines in tissue culture and the level of EGFP expression compared. To assess the intactness of the DNA delivered, a BAC carrying oriP/EBNA‐1 was used to make stably transfected cell lines. Episomal DNA was then rescued into E. coli followed by analysis on a pulsed‐field gel. Three different methods of in vivo delivery were also assessed for delivery of BAC DNA; intravenous injection of DNA/PEI particles, intramuscular injection with electroporation and high‐volume injection into the tail vein.

Results

PEI22 (linear polymer form, 22 kDa) was found to be the most efficient method for delivery of 150‐kb BAC DNA to both cell lines in tissue culture. However, Lipofectamine 2000 was found to give a higher proportion of intact DNA than PEI22 in stably transformed colonies and almost all the DNA delivered by Lipofectamine 2000 was intact. Intravenous injection of DNA/PEI particles was found to be inefficient for delivery of BAC DNA. Intramuscular injection with electroporation of pure BAC DNA was very efficient and expression was maintained for 105 days. High‐volume injection of BAC DNA gave excellent expression in the liver and intact BAC DNA could be rescued 7 days after injection.

Conclusions

These results demonstrate efficient delivery of intact, large (up to 157 kb) DNA constructs for in vitro gene expression and in vivo gene therapy applications. Copyright © 2004 John Wiley & Sons, Ltd.
A synthetic peptide vector system for optimal gene delivery to corneal endothelium
Authors: Collins Louise , Fabre John W.
Published: February 2004

Background

Efficient and non‐toxic gene delivery, preferably with non‐viral DNA vectors readily transferable to clinical practice, is generally regarded as a major limitation for gene therapy.

Methods

A 31 amino acid, integrin‐targeted bifunctional synthetic peptide (polylysine‐molossin), and two (Lys)16‐containing control peptides, were assessed for ex vivo gene delivery to the rabbit cornea. Critical physical properties of polylysine‐molossin/DNA complexes were evaluated and both chloroquine and a 20 amino acid fusogenic peptide were used to promote endocytic exit.

Results

Polylysine‐molossin/DNA complexes and (Lys)16/DNA complexes at 10 µg/ml of DNA were much smaller and much more positively charged in non‐ionic isotonic medium (5% dextrose or 5% dextrose buffered to pH 7.4 in 10 mM Tris) when compared with culture medium or phosphate‐buffered saline (PBS). Addition of the fusogenic peptide (net charge −5) reversed the positive charge of complexes in PBS, and reduced the strong positive charge of polylysine‐molossin/DNA complexes in dextrose. Polylysine‐molossin/DNA complexes in 5% dextrose were much more effective for gene delivery to the cornea when compared with complexes in culture medium, and the fusogenic peptide was much more effective than chloroquine for promoting gene delivery. The optimal DNA/polylysine‐molossin/fusogenic peptide w/w ratio was 1 : 3 : 2 at 10 µg/ml of DNA. Essentially 100% of corneal endothelial cells were transfected under these optimal conditions, without any evidence of toxicity. Integrin‐targeting did not contribute significantly to gene delivery in this system.

Conclusions

This DNA vector system, consisting entirely of synthetic peptides, is ideally suited for clinical applications of gene therapy of the corneal endothelium. Copyright © 2004 John Wiley & Sons, Ltd.
Efficient transfection of non‐proliferating human airway epithelial cells with a synthetic vector system
Authors: Meng Qing‐Hai , Robinson Danielle , Jenkins R. Gisli , McAnulty Robin J. , Hart Stephen L.
Published: February 2004

Background

The poor transfection efficiency of most synthetic vectors in non‐dividing, airway epithelial cells is limiting the development of gene therapy for respiratory diseases such as cystic fibrosis.

Methods

Cultured airway epithelial cells, quiescent or replicating, were transfected with a lipid/peptide synthetic vector system and transfection efficiency assessed by luciferase assays or flow cytometry for green fluorescent protein expression. Tight junctions were disrupted by treatment with ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA). Cell division was inhibited by aphidicolin and assessed by 5‐bromo‐2′‐deoxyuridine (BrdU) incorporation and assay by fluorescence microscopy or flow cytometry. In vivo transfection was performed by intratracheal instillation.

Results

Initial studies showed that this synthetic vector transfected 8% of non‐dividing epithelial cells in culture compared with 45% of subconfluent, dividing cells. However, formulation of the vector with EGTA, which disrupts cellular tight junctions, induced a four‐fold increase in the transfection efficiency of confluent, non‐mitotic cells. The EGTA enhancement of transfection also correlated with a four‐fold increase in vector binding to the cells, presumably via exposed basolateral receptors. Flow cytometry and double immunofluorescent staining for reporter gene expression and BrdU incorporation indicated efficient transfection of non‐proliferating cells in a confluent monolayer by this vector. Furthermore, in vivo transfection of murine lung by intratracheal administration showed a six‐fold enhancement of luciferase expression when lungs were pre‐treated with EGTA.

Conclusions

This study confirms the hypothesis that a lipid/peptide vector transfects non‐dividing cells with high efficiency which contributes to its previously reported efficiency in transfecting bronchial epithelium, making it a good choice for gene transfer studies in the lung. Copyright © 2004 John Wiley & Sons, Ltd.