bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of insulin‐like growth factor binding protein‐3 (IGFBP‐3) in the differentiation of primary human adult skeletal myoblasts
Authors: Foulstone Emily J. , Savage Paul B. , Crown Anna L. , Holly Jeff M.P. , Stewart Claire E.H.
Published: February 2003

Although muscle satellite cells were identified almost 40 years ago, little is known about the induction of their proliferation and differentiation in response to physiological/pathological stimuli or to growth factors/cytokines. In order to investigate the role of the insulin‐like growth factor (IGF)/IGF binding protein (IGFBP) system in adult human myoblast differentiation we have developed a primary human skeletal muscle cell model. We show that under low serum media (LSM) differentiating conditions, the cells secrete IGF binding proteins‐2, ‐3, ‐4 and ‐5. Intact IGFBP‐5 was detected at days 1 and 2 but by day 7 in LSM it was removed by proteolysis. IGFBP‐4 levels were also decreased at day 7 in the presence of IGF‐I, potentially by proteolysis. In contrast, we observed that IGFBP‐3 initially decreased on transfer of cells into LSM but then increased with myotube formation. Treatment with 20 ng/ml tumour necrosis factor‐alpha (TNFα), which inhibits myoblast differentiation, blocked IGFBP‐3 production and secretion whereas 30 ng/ml IGF‐I, which stimulates myoblast differentiation, increased IGFBP‐3 secretion. The TNFα‐induced decrease in IGFBP‐3 production and inhibition of differentiation could not be rescued by addition of IGF‐I. LongR3IGF‐I, which does not bind to the IGFBPs, had a similar effect on differentiation and IGFBP‐3 secretion as IGF‐I, both with and without TNFα, confirming that increased IGFBP‐3 is not purely due to increased stability conferred by binding to IGF‐I. Furthermore reduction of IGFBP‐3 secretion using antisense oligonucleotides led to an inhibition of differentiation. Taken together these data indicate that IGFBP‐3 supports myoblast differentiation. © 2003 Wiley‐Liss, Inc.
Lamellipodial motility in wounded endothelial cells exposed to physiologic flow is associated with different patterns of β1‐integrin and vinculin localization
Authors: Albuquerque Maria Luiza C. , Flozak Annette S.
Published: February 2003

Integrins‐ and cytoskeletal‐associated focal adhesion proteins may participate in the process of endothelial wound closure, but their relationship in these wounds and in the presence of shear forces has not been defined. The goal in this study was to test the hypotheses that (1) modulation of β1‐integrin in human coronary artery endothelial cells (HCAEC) would alter endothelial wound closure under shear stress, and (2) β1‐integrin association with vinculin would be necessary for mediating this closure. HCAEC monolayers were pre‐conditioned to attain alignment by shearing at 12 dynes/cm2 for 18 h in a parallel‐plate flow chamber. Subsequently, they were divided into three groups: (a) control, (b) treated with anti‐β1‐integrin adhesion blocking antibody, or (c) treated with anti‐β1‐integrin adhesion promoting antibody. Next, the monolayers were wounded with a metal spatula, and re‐sheared at 20 dynes/cm2 or left static. Time‐lapse imaging and deconvolution microscopy were then performed for 3 h. Immunocytochemistry for β1‐integrin expression and vinculin was performed on all wounded monolayers. Under shear stress, vinculin localized to the ends of stress fibers, while β1‐integrin took on an intracellular macroaggregate appearance. Treatment with anti‐β1‐integrin adhesion blocking antibody enhanced wound closure, left the vinculin staining at the lamellipodial tips unchanged, but was associated with β1‐integrin staining at the lateral cell edges. Treatment with the anti‐β1‐integrin adhesion promoting antibody retarded wound closure, increased vinculin staining at cell‐cell junctions, and was associated with a fibrillar pattern of β1‐integrin staining. Modulation of β1‐integrin and changes in β1‐integrin and vinculin localization may further our understanding of laminar shear stress‐induced endothelial repair in the coronary circulation. © 2003 Wiley‐Liss, Inc.
CD31 (PECAM‐1)‐bright cells derived from AC133‐positive cells in human peripheral blood as endothelial‐precursor cells
Authors: Kanayasu‐Toyoda Toshie , Yamaguchi Teruhide , Oshizawa Tadashi , Hayakawa Takao
Published: February 2003

To clarify the process of endothelial differentiation, we isolated AC133+ cells and induced the in vitro differentiation of these cells into endothelial cells. AC133+ cells efficiently differentiated into endothelial cells when the cells were cultured on fibronectin‐coated dishes in the presence of vascular endothelial growth factor. Time‐course analysis of the alteration of endothelial markers on cultured AC133+ cells revealed that the expression of CD31 (PECAM‐1) on AC133+ cells was the earliest marker among all of the tested markers. Based on the hypothesis that CD31 is an early indicator during the endothelial differentiation, we examined the relationship between CD31 expression and the ability to differentiate into endothelial cells in cells derived from AC133+ cells. CD31‐bright cells, which were sorted from cultured AC133+ cells, differentiated more efficiently into endothelial cells than had CD31‐positive or CD31‐negative cells, suggesting that CD31‐bright cells may be precursor cells for endothelial cells. In the present study, we identified CD31+ cells derived from cultured AC133+ cells that are able to differentiate to endothelial cells as precursor cells. © 2003 Wiley‐Liss, Inc.
Epidermal growth factor induces an increase in cell adhesion and an arrangement of actin skeleton in stress fibres in pituitary cultured cells from infantile rats but not adult rats
Authors: Toral Claudia , Solano‐Agama M. Carmen , Luna José , Romano Marta C. , Mendoza‐Garrido M. Eugenia
Published: February 2003

The rat anterior pituitary gland undergoes changes in its cyto‐architecture during the second and third weeks of postnatal life. However, little is known about the factors that regulate these tissue conformational changes. The epidermal growth factor (EGF) is one of the growth factors that are synthesized by the pituitary gland, and almost all of the pituitary cells have EGF receptors (EGFR). In addition to the effects of the EGF on mitosis and differentiation, this growth factor can modulate cell adhesion, cell migration, and cytoskeletal organization. In this study we focussed our attention in examining the effects of EGF on the adhesion of cells to the extracellular matrix and on the actin cytoskeletal arrangement of pituitary cells from infantile and adult rats. Our results show that in infantile cells the EGF induces cell adhesion with increase in cell surface area. The arrangement of actin‐F in infantile EGF‐treated cells was in stress fibers and vinculin acquired a striped shape at the membrane border, suggesting the assembly of focal adhesion contacts. In contrast, in adult pituitary cells EGF does not induce any change in cell adhesion, and the cells maintain a rounded shape with an arrangement of actin‐F in thin cortical bands even though, immuno‐localization of the EGFR was observed in adult cells cultured in defined medium. We also looked for the EGFR in membrane preparations from infantile and adult pituitaries, and a marked difference in membrane EGFR was observed between them, the infantile pituitaries showing a significantly higher amount. Our results suggest that in infantile cells EGF induces the assembly of focal adhesion contacts, and that in adult cells the receptor of this growth factor is uncoupled of the signaling pathway by which a rearrangement of actin cytoskeleton occurs. © 2003 Wiley‐Liss, Inc.
Vanadium‐induced apoptosis and pulmonary inflammation in mice: Role of reactive oxygen species
Authors: Wang Liying , Medan Djordje , Mercer Robert , Overmiller Dean , Leornard Stephen , Castranova Vincent , Shi Xianglin , Ding Min , Huang Chuanshu , Rojanasakul Yon
Published: February 2003

Pulmonary exposure to metals and metal‐containing compounds is associated with pulmonary inflammation, cell death, and tissue injury. The present study uses a mouse model to investigate vanadium‐induced apoptosis and lung inflammation, and the role of reactive oxygen species (ROS) in this process. Aspiration of the pentavalent form of vanadium, V (V), caused a rapid influx of polymorphonuclear leukocytes into the pulmonary airspace with a peak inflammatory response at 6 h post‐exposure and resolution by 72 h. During this period, the number of apoptotic lung cells which were predominantly neutrophils increased considerably with a peak response at 24 h accompanied by no or minimum necrosis. After 24 h when the V (V)‐induced inflammation was in the resolution phase, an increased influx of macrophages and engulfment of apoptotic bodies by these phagocytes was observed, supporting the role of macrophages in apoptotic cell clearance and resolution of V (V)‐induced lung inflammation. Electron spin resonance (ESR) studies using lavaged alveolar macrophages showed the formation of ROS, including O2·−, H2O2, and ·OH radicals which were confirmed by inhibition with free radical scavengers. The mechanism of ROS generation induced by V (V) involved the activation of an NADPH oxidase complex and the mitochondrial electron transport chain. The ROS scavenger, catalase (H2O2 scavenger), effectively inhibited both lung cell apoptosis and the inflammatory response, whereas superoxide dismutase (SOD) (O2·− scavenger) and the metal chelator, deferoxamine (inhibitor of ·OH generation by Fenton‐like reactions) had lesser effects. These results indicate that multiple oxidative species are involved in V (V)‐induced lung inflammation and apoptosis, and that H2O2 plays a major role in this process. Published 2003 Wiley‐Liss, Inc.
Lipid factor (bVLF) from bovine vitreous body evokes in EGFR‐T17 cells a Ca2+‐dependent K+ current associated with inositol 1,4,5‐trisphosphate‐independent Ca2+ mobilization
Authors: Camiña Jesus P. , Diaz‐Rodriguez Esther , Harks Erik G.A. , Theuvenet Alexander P.R. , Ypey Dirk L. , Casanueva Felipe F.
Published: February 2003

Bovine vitreous lipid factor (bVLF) is a complex phospholipid isolated from bovine vitreous body with strong Ca2+‐mobilizing activity. In this study, the effects of bVLF on membrane potential were investigated in EGFR‐T17 fibroblasts with the whole‐cell patch clamp technique on monolayer cells, as well as with the fluorescent dye bis‐oxonol as membrane potential‐sensitive probe on monolayer and suspension cells. bVLF induced a transient hyperpolarization characterized by an initial peak and subsequent return to resting membrane potential levels within 1–2 min. The increase of [Ca2+]i was concomitant with an outward current responsible for the hyperpolarizing response. Results with: (a) high [K+]o media; (b) the monovalent cation ionophore gramicidin; and (c) substitution of K+ with Cs+ in the intracellular solution were consistent with the involvement of K+ channels. The bVLF‐induced hyperpolarization was blocked by the K+ channel blockers, quinine and tetraethylamonium chloride, and partially affected by 4‐aminopyridine. The calcium ionophore ionomycin caused a similar hyperpolarization as bVLF. When intracellular calcium was buffered by adding BAPTA to the pipette solution, bVLF‐activated outward current was prevented. Moreover, the hyperpolarization response was strongly reduced at low doses (3 nM) of specific Ca2+‐activated K+ channel blockers, charybdotoxin and iberiotoxin. Based on these observations we conclude that bVLF hyperpolarizes the cells via the activation of a Ca2+‐dependent K+ current. In addition, it was observed that bVLF did not have a significant effect on intercellular communication measured by a single patch‐electrode technique. Thus, membrane potential changes appeared to belong to the earliest cellular responses triggered by bVLF, and are closely associated with phosphatidic acid‐dependent [Ca2+]i mobilization. © 2003 Wiley‐Liss, Inc.
Mast cell‐mediated apoptosis of endothelial cells in vitro: A paracrine mechanism involving TNF‐α‐mediated down‐regulation of bcl‐2 expression
Authors: Lätti Soili , Leskinen Markus , Shiota Naotaka , Wang Yenfeng , Kovanen Petri T. , Lindstedt Ken A.
Published: February 2003

Degranulated mast cells are present in the subendothelial space of eroded (de‐endothelialized) coronary atheromas. Upon degranulation, mast cells secrete into the surrounding tissue an array of preformed and newly synthesized mediators, including proapoptotic molecules, such as chymase and TNF‐α. In a co‐culture system involving rat serosal mast cells and rat cardiac (microvascular) endothelial cells, we could show, by means of competitive RT‐PCR, immunoblotting, immunocytochemistry, annexin staining, flow cytometry, and DNA‐laddering, that stimulation of mast cells with ensuing degranulation rapidly (within 30 min) down‐regulated the expression of both bcl‐2 mRNA and protein, with subsequent induction of apoptosis in the endothelial cells. The major effect of bcl‐2 down‐regulation resided in the exocytosed granule remnants, a minor effect also being present in the granule remnant‐free supernatant. No significant changes were observed in the expression levels of the pro‐apoptotic protein, bax. The mast cell‐mediated apoptotic effect was partially (70%) dependent on the presence of TNF‐α and involved the translocation of cytochrome C from mitochondria into cytoplasm. These results are the first to show that one of the cell types present in the atherosclerotic plaques, namely the mast cell, by releasing both granule‐remnant‐bound and soluble TNF‐α, may contribute to the erosion of atherosclerotic plaques by inducing apoptosis in adjacent endothelial cells. Published 2003 Wiley‐Liss, Inc.
Critical role of both p27KIP1and p21CIP1/WAF1 in the antiproliferative effect of ZD1839 (‘Iressa’), an epidermal growth factor receptor tyrosine kinase inhibitor, in head and neck squamous carcinoma cells
Authors: Di Gennaro Elena , Barbarino Marcella , Bruzzese Francesca , De Lorenzo Sonya , Caraglia Michele , Abbruzzese Alberto , Avallone Antonio , Comella Pasquale , Caponigro Francesco , Pepe Stefano , Budillon Alfredo
Published: February 2003

High expression of the epidermal growth factor receptor (EGFR) has been implicated in the development of squamous‐cell carcinomas of head and neck (SCCHN). ZD1839 (‘Iressa’) is an orally active, selective EGFR‐TKI (EGFR‐tyrosine kinase inhibitor) that blocks signal transduction pathways implicated in proliferation and survival of cancer cells, and other host‐dependent processes promoting cancer growth. We have demonstrated that ZD1839 induces growth arrest in SCCHN cell lines by inhibiting EGFR‐mediated signaling. Cell cycle kinetic analysis demonstrated that ZD1839 induces a delay in cell cycle progression and a G1 arrest together with a partial G2/M block; this was associated with increased expression of both p27KIP1 and p21CIP1/WAF1 cyclin‐dependent kinase (CDK) inhibitors. The activity of CDK2, the main target of CIP/KIP CDK inhibitors, was reduced in a dose‐dependent fashion after 24 h of ZD1839 treatment and this effect correlated to the increased amount of p27KIP1 and p21CIP1/WAF1 proteins associated with CDK2‐cyclin‐E and CDK2‐cyclin‐A complexes. In addition, ZD1839‐induced growth inhibition was significantly reduced in cell transfectants expressing p27KIP1 or p21CIP1/WAF1 antisense constructs. Overall, these results as well as the timing of the effect of ZD1839 on G1 arrest and p27KIP1 and p21CIP1/WAF1 upregulation, suggest a mechanistic connection between these events. © 2003 Wiley‐Liss, Inc.
Induction of globin mRNA expression by interleukin‐3 in a stem cell factor‐dependent SV‐40 T‐antigen‐immortalized multipotent hematopoietic cell line
Authors: Cairns Linda , Cirò Marco , Minuzzo Mario , Morlé François , Starck Joëlle , Ottolenghi Sergio , Ronchi Antonella
Published: February 2003

Erythropoiesis requires the stepwise action on immature progenitors of several growth factors, including stem cell factor (SCF), interleukin 3 (IL‐3), and erythropoietin (Epo). Epo is required to sustain proliferation and survival of committed progenitors and might further modulate the level of expression of several erythroid genes, including globin genes. Here we report a new SCF‐dependent immortalized mouse progenitor cell line (GATA‐1 ts SCF) that can also grow in either Epo or IL‐3 as the sole growth factor. When grown in SCF, these cells show an “open” chromatin structure of the β‐globin LCR, but do not significantly express globin. However, Epo or IL‐3 induce globin expression and are required for its maintainance. This effect of IL‐3 is unexpected as IL‐3 was previously reported either to be unable to induce hemoglobinization, or even to antagonize it. This suggests that GATA‐1 ts SCF cells may have progressed to a stage in which globin genes are already poised for expression and only require signal(s) that can be elicited by either Epo or IL‐3. Through the use of inhibitors, we suggest that p38 may be one of the molecules modulating induction and maintenance of globin expression. © 2003 Wiley‐Liss, Inc.
Non‐selective membranes for separations
Authors: Cussler Edward L
Published: February 2003

Membranes which give high fluxes without selectivities provide a large interfacial area between fluid phases which is independent of the normal constraints of loading and flooding. These membranes offer a largely unexplored route to separation process intensification. Three examples are given in the paper. First, studies of hollow fiber blood oxygenators show that flows which are only a few percent from uniform can reduce overall mass transfer by an order of magnitude. Second, flat sheet membrane evaporators promise the performance of a centrifugal evaporator at a fraction of that unit's cost. Third, distillation in hollow fibers means that the height of the transfer units can be smaller than 0.1 cm, indeed as small as desired.

© 2003 Society of Chemical Industry
New internals for urea production reactors
Authors: Bozzano G , Dente M , Zardi F
Published: February 2003

Fluid dynamics and its influence on heat and mass transport rates in gas–liquid reactors is, in general, an important starting point for development of a process design. Improvements in the understanding of these aspects can be particularly fruitful in the case of urea reactors where the fluid‐dynamic patterns are complicated by the co‐current flow of two phases and the bubbling mode of the vapors. The analysis of such systems highlighted the non‐optimal design of existing reactors and led to the conception of new reactor internals. Several industrial applications demonstrate the ability of the new configuration to improve reactor efficiency. Both energy‐saving and production increases were obtained. This is a further demonstration that even mature technologies can be improved, leading not only to economic advantages, but also to a reduction in their environmental impact.

© 2003 Society of Chemical Industry
Gas–liquid mass transfer in a 15 cm diameter reciprocating plate column
Authors: Rama Rao N V , Baird M H I
Published: February 2003

Data are reported on the absorption of oxygen by water under countercurrent flow conditions, in a 15 cm diameter reciprocating plate bubble column. Amplitude (half stroke) is set at 12.7 mm and reciprocation frequencies up to 5 Hz have been employed. Five different types of plate have been compared; two of the types are multiperforated and three of the types are ‘donut’ plates with a single central hole. When the comparison is made in terms of the volumetric mass transfer coefficient (kla) and power input per unit mass, the best of the five types of plate is a multiperforated plate with small holes of diameter 6.35 mm.

© 2003 Society of Chemical Industry
Ozone oxidation in a rotating packed bed
Authors: Lin Chia‐Chang , Liu Wen‐Tzong
Published: February 2003

The feasibility of applying a novel rotating packed bed to the ozone oxidation process is investigated. Ozone oxidation experiments were conducted to examine how various operating variables affect the decolorization of dyes in aqueous solutions system. Rotor speeds ranged from 380 to 1748 rpm, providing 10∼202 equivalent gravitational force. Experimental results indicate that the centrifugal force positively affects the decolorization efficiency. Furthermore, it is shown that owing to its low ozone mass transfer resistance, a rotating packed bed can be used to increase the efficiency of the ozone oxidation process. Our results further demonstrate that the decolorization efficiency increases with either an decreasing initial dye concentration or liquid flow rate.

© 2003 Society of Chemical Industry
Intensification of random packing via CFD simulation, PIV measurement and traditional experiments
Authors: Fei W Y , Wang Y D , Song X Y , Yin Y D , Sun L Y
Published: February 2003

It is shown from CFD simulation and particle image velocimetry (PIV) measurements that the flow field around ring packing is impacted by their height/diameter ratio and inclination. The results indicate that it is better to decrease the height/diameter ratio of ring packing to intensify the separation processes in the packing bed. Based on a systematic study, a new Plum Flower Mini Ring (PFMR) was developed to meet the demands of separation column intensification.A comparison of the PFMR, Pall Ring and Intalox Saddle in a 600 mm diameter column with an air–oxygen–water system over a wide range of liquid loads is presented. It was shown from the experiments that the PFMR had a much lower pressure drop, much larger throughput and better mass transfer efficiency than Pall Rings and Intalox Saddles.

© 2003 Society of Chemical Industry
Physical modelling for airlift loop tanks
Authors: Trilleros J A , Díaz R , Redondo P
Published: February 2003

Airlift loop tanks (ALT) are used in a many industrial applications where close contact among the different phases is essential. We can find such examples in the chemical, petrochemical, biochemical and minerals processing industries. The ALT principle is based on creating a zone within the tank through which gas rises. In this way a difference in density is obtained between the gas–liquid–solid riser zone and the liquid–solid downcomer zone; this density difference induces circulation of the liquid and solid phases through both zones. When the gas velocity is increased, gas bubbles inside the liquid phase are also transported into the downcomer. This circulation creates a good mixture of all three phases and efficient suspension of solid in the liquid. A main parameter that characterizes ALT operation is the circulation velocity, which can be quantified by the riser superficial liquid velocity. This parameter is a function of the operational adjustable variables such as gas flow‐rate, liquid and solid densities, fractional holdup, solid size and tank geometry. The following variables were determined by experimental work: pressure losses in ALT, superficial solid velocity in riser and downcomer, superficial liquid velocity in riser and solid holup in riser. Finally the relationship between these variables was established.

© 2003 Society of Chemical Industry
Modelling of film flow over a spinning disk
Authors: Sisoev Grigori M , Matar Omar K , Lawrence Christopher J
Published: February 2003

Film flows over a spinning disk are applied to intensify heat and mass transfer processes, which need large contact surfaces between a liquid and surrounding gas. An inherent property of this flow is the formation of waves, whose amplitude may have the same scale as the film thickness. Experimental observations indicate a strong dependence of heat and mass transfer processes on these surface structures, especially in the case of large amplitude waves. This paper reports mathematical modelling of this flow.

© 2003 Society of Chemical Industry
Generating innovative process designs using limited data
Authors: Sharratt Paul N , Wall Kevin , Borland John N
Published: February 2003

Key constraints in process innovation are the time and cost spent obtaining data to identify and verify novel processes. Businesses are under increasing pressure to deliver products in shorter times; pressure which restricts and often prevents access to innovative and intensive processing options. The Britest project has identified key decisions in process design and the associated minimum data requirements. These involve identification and manipulation of the relevant rate processes and consideration of the phases of matter that are (or could be) present. By use of qualitative and semi‐quantitative reasoning it is possible to produce a range of possible process options very early in design. This is particularly useful in the low‐tonnage chemicals sectors (fine and effect chemicals) where process design is primarily an empirical activity. It also helps to deal rationally with the complex chemistry prevalent in those industries. The early identification of options allows timely development of experimental programmes to evaluate the options. An illustrative example based on a diazotisation and the associated decomposition reaction is presented.

© 2003 Society of Chemical Industry
Study of the preparation and composition of the metallic function for the selective hydrogenation of CO2 to gasoline over bifunctional catalysts
Authors: Ereña Javier , Arandes José M , Garoña Raúl , Gayubo Ana G , Bilbao Javier
Published: February 2003

Bifunctional catalysts for the transformation of carbon dioxide and hydrogen into gasoline have been prepared by conventional and novel processes and characterized by measurement of BET surface area and volume and distribution of pores, and by X‐ray diffraction, FTIR spectroscopy and X‐ray fluorescence. The effects of the preparation conditions and of the atomic ratios between the metals on the structure and on the properties of the catalysts were studied.

© 2003 Society of Chemical Industry
Combustion of chlorinated hydrocarbons in catalyst‐coated sintered metal fleece reactors
Authors: Everaert K , Mathieu M , Baeyens J , Vansant E
Published: February 2003

Incinerators emit chlorinated hydrocarbons, such as polychlorinated benzenes (PCBz) and phenols (PCPh), polychlorinated biphenyls (PCB) and polychlorinated dibenzodioxins and furans (PCDD/F), as very dilute streams. High temperatures (>1000 °C) are required in traditional oxidizers. From an energy‐saving perspective and to avoid de novo synthesis of PCDD/F, exhaust gas clean‐up must be performed at low temperatures (250–350 °C). Catalytic combustion can be applied in this temperature range and different reactor layouts are used (eg monoliths, honeycomb). The present investigation uses a novel catalyst‐coated sintered metal fleece. Thin metal fibers are sintered (non‐woven) to fleece of various thickness, structure and porosity. V–Ti–W catalysts are examined. The paper will briefly review the catalyst coating method suitable to provide a structured fleece reactor with adequate characteristics. Experiments were carried out in the temperature range of 260–340 °C with various hydrocarbons injected in a carrier air stream. The experimental investigations demonstrated: (i) that the conversion of the hydrocarbons (volatile organic compounds, VOC) is independent of the oxygen concentration, corresponding to a zero‐order dependence of the reaction rate; (ii) that the conversion of the hydrocarbons is a first‐order reaction in the VOC; (iii) that the oxidation of the VOC proceeds to a greater extent with increasing temperature, with chlorine substitution enhancing the reactivity, and (iv) that the reaction rate constant follows an Arrhenius‐dependence with activation energies between 37.3 and 58.4 kJ mol−1. An assessment of the results leads to a model expression with kinetic reaction control. This model can be used in a scale‐up strategy.

© 2003 Society of Chemical Industry
A novel separation technique – gas carrying evaporation: theory and application
Authors: Ma Feng , Yu Zhijia , Wang Jun , Ding Jie , Xu Weiqin , Shen Ziqiu
Published: February 2003

To avoid or mitigate scaling or thermal deterioration in the process of evaporation a novel process – Gas Carrying Evaporation (GCE) has been developed with the concept of an ‘interfacial vaporization heat sink’. In the GCE process, an inert gas was introduced at the bottom of vertical heating tubes. Due to the effect of the ‘heat sink’, the temperature of the heating wall is lowered, nucleate boiling on the heating wall is suppressed, and solvent vaporization mainly takes place at the gas–liquid interface in the two‐phase flow bulk. Therefore, both thermal deterioration and scaling on the heating wall are avoided or mitigated, and the heat transfer is greatly enhanced. The process of GCE has been used in several industries for the evaporation of thermally sensitive and easily depositing solutions. In this paper, the development of GCE, the theory of heat transfer augmentation by the interfacial vaporization heat sink, and the characteristics and applications of GCE are described and discussed.

© 2003 Society of Chemical Industry
Modeling of electrostatic spray in a venturi scrubber
Authors: Yang H T , Viswanathan S , Balachandran W , Ray M B
Published: February 2003

This paper summarizes the results of an investigation into the distribution of the droplets produced by electrostatic nozzles inside a Pease–Anthony venturi scrubber. The model simulates the flux distribution of charged droplets injected from an electrostatic nozzle in the scrubber under the combined influence of hydrodynamic and electric fields. The effects of operating parameters, such as gas velocity, diameter of the scrubbing droplets, charge‐to‐mass ratio and liquid‐to‐gas ratio, on the flux distribution of the water droplets in the throat of the scrubber are also investigated. The model takes into account initial liquid momentum, electric, hydrodynamic and gravitational forces, and eddy diffusion. The flux distribution of the scrubbing liquid in the presence of an electric field is much improved over a conventional scrubber, and the effect increases with the increase in charge‐to‐mass ratio. However, the effect of an electric field on the droplet flow pattern for small drops in a strong hydrodynamic field is negligible. Simulated results are in good agreement with the experimental data obtained in the laboratory.

© 2003 Society of Chemical Industry
Segregation of binary mixture of particles in a bladed mixer
Authors: Zhou Y C , Yu A B , Bridgwater J
Published: February 2003

This paper presents a numerical study of the flow and segregation of particles over flat blades in a vertical cylindrical mixer by means of a modified discrete element method. Simulations are conducted using a binary mixture of spheres, where the blade's rotating speed, particle size, volume fraction and particle density are the variables considered. Similar flow features are found for all the cases considered: particles rise to form a heap in front of a blade and then either flow downward on the bed surface over the blade or to the base of the heap to rejoin the flow toward the blade, and there is a recirculating zone in front of the blade. However, different types of mixing behaviour can be observed. Particles with large size or light density are mainly in the top layer of the mixing bed, while small and heavy particles remain in the bottom of the mixing bed and in front of the blades. The segregation pattern resulting from size difference is not the same as that resulting from density difference. The force evolution in these two binary systems also differs, although at the initial stage large/light particles always receive a relatively larger vertical force than small/heavy particles, leading to segregation that can be maintained at the later stage. Decreasing the size or density difference promotes the mixing performance. Changing the blade speed affects the mixing kinetics but not the mixing quality.

© 2003 Society of Chemical Industry
Modelling the kinetics of lipase‐catalysed oil hydrolysis in an electrically enhanced liquid–liquid system
Authors: Jones E , Weatherley L R
Published: February 2003

This study focussed on the use of high voltage electrostatic fields to spray solutions of the non‐specific lipase Candida rugosa into high oleate sunflower oil and to determine rates of hydrolysis. Significant increases in reaction rate are reported. The kinetics were analysed using a modified reaction model for enzymatic reactions at free liquid interfaces. Similar data for hydrolysis rate within dispersions formed by mechanical agitation in a recycle reactor were similarly measured and interpreted. In both cases good agreement was obtained between the experimental measurements and the predicted results.

© 2003 Society of Chemical Industry
A new process for toxic metal uptake by a kraft lignin
Authors: Crist DeLanson R , Crist Ray H , Martin J Robert
Published: February 2003

A new approach toward removing toxic metals from industrial process water has been investigated using kraft lignin, a by‐product of paper production. A detailed study on a kraft pine lignin powder (Indulin AT from MeadWestvaco), which has acid functions that can act as ion‐exchange sites, has shown that uptake of divalent toxic metals is accompanied by a release of protons or existing metals from the lignin. Equilibrium constants for displacement of protons decreased with pH, and equilibrium constants for metal–metal exchange showed that binding strengths follow the order (highest to lowest): Pb, Cu, Zn, Cd, Ca, Sr. A demonstrated stoichiometry of one mole Ca displaced for one mole of metal (Sr or Cd) sorbed is fully consistent with a chemical reaction of ion exchange and difficult to explain by frequently used adsorption models (Langmuir adsorption isotherm and biotic ligand model). Since the powder after metal uptake is hard to separate from purified water on a large scale, a novel formulation has been investigated for toxic metal removal.

© 2003 Society of Chemical Industry
Non‐traditional three‐phase reactor setup for simultaneous acoustic irradiation and hydrogenation
Authors: Mikkola Jyri‐Pekka , Kubicka David , Kuusisto Jyrki , Granholm Nina , Salmi Tapio , Holmbom Bjarne
Published: February 2003

A tailor‐made autoclave setup for simultaneous acoustic irradiation and hydrogenation was used in the hydrogenation of fatty acids and carbohydrates. The aim was not to perform actual sonochemistry but to retard deactivation of the catalyst by means of acoustic irradiation. The catalyst used was a Raney nickel one that tends to deactivate quite rapidly from batch to batch. The results indicated that in the case of the aqueous system (xylose hydrogenation to xylitol) the effect is clear. In the case of the fatty acids one actually observed an enhancement of the reaction rate: with recycled catalyst the second and third batch proceeded somewhat faster than the first one.

© 2003 Society of Chemical Industry
Gluconic acid production under varying fermentation conditions by Aspergillus niger
Authors: Singh Om V , Jain Rakesh K , Singh Rajesh P
Published: February 2003

The production of gluconic acid with respect to varying substrate concentrations in submerged (SmF), semisolid‐state (SmSF), surface (SF), and solid‐state surface (SSF) fermentations was analyzed. Under the various fermentation conditions the biomass and specific growth rate varied with different concentrations of glucose. The highest level of gluconic acid (106.5 g dm−3) with 94.7% yield was obtained under SSF conditions. In all cases the maximum degree of gluconic acid conversion was observed at on initial substrate concentration of 120 g dm−3. The rate of glucose uptake increased on increasing the initial glucose concentration and glucose utilization was observed to be highest (89–94%) in the SmSF process and was comparable with the SSF and SF processes. The maximum rate of cell growth was obtained in all processes at an initial glucose concentration of 120 g dm−3. The gluconic acid production and change in pH were analyzed at varying time intervals and it was observed that the SmF and SmSF processes were completed within 6 days of incubation whereas the highest yield was observed after 12 days of incubation and continued thereafter in the SSF process.

© 2003 Society of Chemical Industry
Adsorption of dioxins and furans from flue gases in an entrained flow or fixed/moving bed reactor
Authors: Everaert Kim , Baeyens Jan , Creemers Claude
Published: February 2003

Under certain operating conditions, polychlorinated dioxins and furans occur in the flue gases of thermal processing plants. Current EU Directives limit the concentration of these emissions to less than 0.1 ng toxicity equivalents (TEQ) per standard cubic metre of dry gas at 11 vol% O2. These Directives have been included in the emission regulations of most of the EU countries. Dioxins and furans are not particular to incinerators; they can also originate from metallurgical and other thermal processes when these are operated under unfavourable conditions. Adsorption methods employing non‐flammable carbonaceous adsorbents (activated carbon, lignite) are particularly well suited for removing PCDD/Fs. For adsorption, which requires the sorbent to be brought in contact with the gas to be cleaned, various processes are currently available, ie classical adsorption in moving/fixed bed filters or the technique of adsorption in an entrained dust cloud with a downstream fabric filter or electrostatic precipitator to remove the spent sorbent from the waste gas (entrained process). The paper will firstly assess both adsorption concepts; it will then use results obtained from operational tests in incineration plants for municipal and industrial waste to describe the efficiency of the dioxin‐sorption in an entrained bed (pneumatic transport of pulverized adsorbent) and a fixed/moving bed (granular adsorbent). Variations in the dosing rate and the use of different adsorbents, as well as the operating temperature, identify the selection criteria for determining the process‐engineering optimum for flue gas cleaning. The paper will demonstrate that the PCDD/F emissions can be reduced to below 0.1 ng TEQ Nm−3 and will identify the operating conditions required to achieve this standard.

© 2003 Society of Chemical Industry
A study of velocity and residence time of single bubbles in a gassed oscillatory baffled column: effect of oscillation amplitude
Authors: Oliveira Mónica S N , Fitch Andrew W , Ni Xiong‐Wei
Published: February 2003

In this paper, the experimental evaluation of velocity and residence time of single bubbles of different sizes in a gassed oscillatory baffled column (OBC) using a high‐speed imaging technique is reported. This work is particularly concentrated on the effect of oscillatory amplitude. The results show that the instantaneous axial bubble velocities vary up to four times with respect to the mean value at an oscillatory amplitude greater than 2 mm. The ratio of the radial to axial bubble velocity increases beyond unity for the highest oscillation amplitude investigated. The direct measurement of residence time of the bubbles within a baffled cell is also reported.

© 2003 Society of Chemical Industry
A review on combustion synthesis of novel materials: recent experimental and modeling results
Authors: Cincotti Alberto , Licheri Roberta , Locci Antonio Mario , Orrù Roberto , Cao Giacomo
Published: February 2003

Solid–solid and gas–solid self‐propagating high temperature reactions are exploited for interesting and relatively new technological applications in the field of combustion synthesis. This paper describes the characteristics of this technique by focusing on the synthesis of some reacting systems recently investigated by Cao and coworkers, such as Ti3Al, TiAl, and ZrO2/SiC. Experimental as well as modeling issues are tackled by pointing out the need of a proper comparison between the corresponding results related to their dynamic behavior, in the framework of a structural dynamics approach. This methodological procedure seems to be able to determine a reliable set of model parameters necessary for successful scaling up and industrial applicability of combustion synthesis‐based technology.

© 2003 Society of Chemical Industry
Modelling of mixing in a Taylor‐Couette reactor with axial flow
Authors: Syed Amjad , Früh Wolf‐Gerrit
Published: February 2003

Taylor–Couette flow with superimposed axial flow is becoming increasingly accepted as a novel reactor type offering a wide range of mixing regimes within a single reactor vessel, depending on the operating conditions of the reactor. To exploit the potential of such a reactor fully, the mixing processes in the reactor have to be well understood. A variant of an established model to simulate flow in a Taylor–Couette reactor with axial flow is presented. The model, which is based on the description of the flow as a linked network of stirred tanks, attempts to develop a parameterisation of the mass exchange processes between Taylor vortices and the by‐pass stream on a rational basis. Some numerical results are presented and compared with results from the literature.

© 2003 Society of Chemical Industry
TNO's work on intensification: practical examples
Authors: Walpot Jan I
Published: February 2003

TNO, a Dutch organisation for contract research, is and has been involved in numerous process intensification projects in close collaboration with national and international process industries. TNO has different facilities available to fulfil the demands of intensification projects. Depending on the focus of a project, a multidisciplinary team conducts experimental research, feasibility studies, process modelling, process design, pilot research and/or E‐evaluations (economics, environment, energy). In this conference paper practical cases are described concerning novel processing techniques as well as novel reactors.

© 2003 Society of Chemical Industry
Internal heat integration – the key to an energy‐conserving distillation column
Authors: Olujic Z , Fakhri F , de Rijke A , de Graauw J , Jansens P J
Published: February 2003

This paper illustrates the thermal energy conservation potential of the so‐called heat integrated distillation column (HIDiC), which combines advantages of direct vapour recompression and diabatic operation at half of the normal column height. In a typical close boiling mixture separation, compared with a column utilising the usual vapour recompression scheme, HIDiC halved the consumption of exergy at approximately the same capital cost, indicating a strikingly short pay‐off time. The complexities of integrating the heat transfer equipment in the stripping section with proven gas/liquid contacting devices, which may work adversely to practical implementation of HIDiC concept, are also addressed.

© 2003 Society of Chemical Industry
Simplified protein purification using engineered self‐cleaving affinity tags
Authors: Wood David W
Published: February 2003

The biological revolution, spurred on by the completion of the human genome project, will increase the demand for inexpensive and reliable methods for protein expression and purification. Over the past 20 years, several technologies have been developed where target proteins or expression systems are manipulated at the genetic level to increase productivity. The use of genetically‐fused affinity tags has been particularly successful, and this technique has become ubiquitous in research. However, the high cost of this approach, along with some regulatory issues, have prevented it from becoming more widely adopted at large scale. Recently, self‐cleaving protein elements have been developed that can effectively make affinity tags self‐cleaving, allowing the release of the product directly from the affinity column under extremely mild conditions. The low cost of this approach, combined with the power of an affinity separation, promise to make this an exciting new purification technology for future research and manufacturing applications.

© 2003 Society of Chemical Industry
Enhancement of ultrafiltration using gas sparging: a comparison of different membrane modules
Authors: Cui Zhanfeng , Taha Taha
Published: February 2003

Ultrafiltration is widely used in the chemical, pharmaceutical, food and water industries. Practical difficulties arise in designing and operating the process due to concentration polarisation and membrane fouling. Enhancement of ultrafiltration is highly desirable to achieve a higher permeate flux at a fixed energy input, or a reduced energy input whilst maintaining the level of permeate flux, or an improved selectivity of the membrane. One effective, simple, and economic technique used to enhance ultrafiltration is the use of gas bubbles, ie injecting gas into the feed stream to create a gas–liquid two‐phase cross‐flow operation. In this paper, an attempt is made to compare the effect of ‘bubbling’ on the ultrafiltration performance, using different membrane modules (in particular, tubular and hollow fibre membrane modules). The difference in performance can be related to the feature of two‐phase flow hydrodynamics and its respective effect on mass transfer. The advantages and drawbacks of using this technique to enhance ultrafiltration are discussed.

© 2003 Society of Chemical Industry
Using process intensification in the actinide processing industry
Authors: Yarbro Stephen L , Schreiber Stephen B
Published: February 2003

All industrially significant actinides have hazards associated with their storage and handling. All are radioactive and potentially fissile which limits the amount of material that can be processed in a given unit operation to prevent a criticality accident. To protect workers from the radiation and direct exposure to these toxic elements, processing is done in remote‐handling facilities or within engineered barriers like glove boxes. Such facilities are expensive to build, operate, and maintain. Actinides also have high waste handling, storage and disposal costs due to their radioactivity and toxicity. These processing constraints make actinide processing an excellent candidate for process intensification as they are separated from undesirable fission products or purified to usable product. Using specially designed equipment that enhances the mixing and mass transfer or combining several unit operations in single unit are typical of process intensification. Annular centrifugal contactors are an excellent example of applying Taylor–Couette type flow to mix two immiscible fluids and then separating them centrifugally. Hence, two operations are combined in one unit.

© 2003 Society of Chemical Industry
Production of pullulan using an oscillatory baffled bioreactor
Authors: Gaidhani Hemraj K , McNeil B , Ni Xiong‐Wei
Published: February 2003

Pullulan is a well‐known extracellular polysaccharide produced by the aerobically growing yeast‐like fungus Aureobasidium pullulans (A pullulans). Pullulan has a wide range of commercial and industrial applications, eg it is used in adhesives, in laminates or nylon‐like fibres and fabrics, and in various foods as a low calorie ingredient. Pullulan itself is produced and deposited on the outside of the fungal cells, and because of the low oxygen permeability of the pullulan, this layer acts as a barrier for the transfer of oxygen from the medium to the fungus. This could be detrimental to the survival of the cells and, in turn, restrict the cultivation of the pullulan. In pullulan fermentation it is therefore desirable to break up and remove this layer of pullulan adherent to the cells. The conventional impeller‐driven vessels often exhibit a gradient in mixing capabilities, with high intensities at and near the impeller but low intensities in peripheral regions. Such gradients increase significantly with the scale. The existence of the mixing gradient in a given vessel can potentially inhibit the process of pullulan generation in regions distant from the impeller, leading to reduced productivity. The oscillatory baffled bioreactor (OBB) offers enhanced and uniform mixing at very low shear rate compared with conventional mixing vessels; this would provide better control over the cultivation of pullulan. In this paper, the production of pullulan in the OBB is reported and compared with the fermentation process carried out in a conventional stirred tank fermenter.

© 2003 Society of Chemical Industry