bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiac and Renal Function are Progressively Impaired with Aging in Zucker Diabetic Fatty Type II Diabetic Rats
Authors: Baynes John , Murray David B.
Published: August 2010

This study investigated the temporal relationship between cardiomyopathy and renal pathology in the type II diabetic Zucker diabetic fatty (ZDF) rat. We hypothesized that changes in renal function will precede the development of cardiac dysfunction in the ZDF rat. Animals (10 weeks old) were divided into four experimental groups: Lean Control (fa/?) LC (n = 7), untreated ZDF rats (n = 7) sacrificed at 16 weeks of age, and LC (n = 7) untreated ZDF rats (n = 9) sacrificed at 36 weeks of age. LV structural/functional parameters were assessed via Millar conductance catheter. Renal function was evaluated via markers of proteinuria and evidence of hydronephrosis. LV mass was significantly less in the ZDF groups at both time points compared to age‐matched LC. End diastolic volume was increased by 16% at 16 weeks and by 37% at 36 weeks of age (p < 0.05 vs. LC). End diastolic pressure and end systolic volume were significantly increased (42% and 27% respectively) at 36 weeks of age in the ZDF compared to LC. Kidney weights were significantly increased at both 16 and 36 week in ZDF animals (p < 0.05 vs. LC). Increased urinary albumin and decreased urinary creatinine were paralleled by a marked progression in the severity of hydronephrosis from 16 to 36 weeks of age in the ZDF group. In summary, there is evidence of progressive structural and functional changes in both the heart and kidney, starting as early as 16 weeks, without evidence that one pathology precedes or causes the other in the ZDF model of type II diabetes.
New Strategies for Alzheimer Disease and Cognitive Impairment
Authors: Maiese Kenneth , Chong Zhao Zhong , Hou Jinling , Shang Yan Chen
Published: August 2010

Approximately five million people suffer with Alzheimer disease (AD) and more than twenty‐four million people are diagnosed with AD, pre‐senile dementia, and other disorders of cognitive loss worldwide. Furthermore, the annual cost per patient with AD can approach $200,000 with an annual population aggregate cost of $100 billion. Yet, complete therapeutic prevention or reversal of neurovascular injury during AD and cognitive loss is not achievable despite the current understanding of the cellular pathways that modulate nervous system injury during these disorders. As a result, identification of novel therapeutic targets for the treatment of neurovascular injury would be extremely beneficial to reduce or eliminate disability from diseases that lead to cognitive loss or impairment. Here we describe the capacity of intrinsic cellular mechanisms for the novel pathways of erythropoietin and forkhead transcription factors that may offer not only new strategies for disorders such as AD and cognitive loss, but also function as biomarkers for disease onset and progression.
Transient Glutathione Depletion Determines Terminal Differentiation in HL‐60 Cells
Authors: Krance Suzanne M. , Keng Peter C. , Palis James , Ballatori Nazzareno
Published: August 2010

To better define the role of glutathione (GSH) in cell differentiation, the present study measured GSH concentrations during terminal HL‐60 cell differentiation, in the presence and absence of differentiation‐inducing agents, and in the presence and absence of GSH altering agents. Interestingly, there was a small transient increase in intracellular GSH levels during dimethyl sulfoxide (DMSO) or 1α,25‐dihydroxyvitamin D3 (VD3) induced differentiation. This increase coincided with an increase in nitroblue tetrazolium (NBT) reduction capacity, a measure of superoxide anion production, but there was no apparent change in the GSH/glutathione disulfide (GSSG) ratio. Surprisingly, treatment of cells with low doses of 1‐chloro‐2,4‐dinitrobenzene (CDNB; 5 µM) or diethylmaleate (DEM; 0.5 mM), which transiently deplete GSH levels to about 40% of control levels, resulted in enhanced differentiation of HL‐60 cells exposed to VD3 or all‐trans‐retinoic acid (ATRA), as well as under un‐induced conditions (i.e., spontaneous differentiation). Enhanced differentiation occurred when cells were treated with the GSH‐depleting agents 4 hours after treatment with differentiation inducers. These findings indicate that intracellular GSH levels are regulated in a complex fashion during HL‐60 cell differentiation, and that transient GSH depletion using low doses of CDNB and DEM enhances the differentiation process.
Markers of Oxidative Stress in Erythrocytes and Plasma During Aging in Humans
Authors: Pandey Kanti Bhooshan , Rizvi Syed Ibrahim
Published: August 2010

Aging is an inevitable universal biological process, which can be characterized by a general decline in physiological function with the accumulation of diverse adverse changes and increased probability of death. Among several theories, oxidative stress/free radical theory offers the best mechanistic elucidation of the aging process and other age‐related phenomenon. In the present paper, we discuss the aging process and have focused on the importance of some reliable markers of oxidative stress which may be used as biomarkers of the aging process.
Antineoplastic Activities of MT81 and Its Structural Analogue in Ehrlich Ascites Carcinoma‐Bearing Swiss Albino Mice
Authors: Choudhury Sujata Maiti , Gupta Malaya , Majumder Upal Kanti
Published: August 2010

Many fungal toxins exhibit in vitro and in vivo antineoplastic effects on various cancer cell types. Luteoskyrin, a hydroxyanthraquinone has been proved to be a potent inhibitor against Ehrlich ascites tumor cells. The comparative antitumor activity and antioxidant status of MT81 and its structural analogue [Acetic acid‐MT81 (Aa‐MT81)] having polyhydroxyanthraquinone structure were assessed against Ehrlich ascites carcinoma (EAC ) tumor in mice. The in vitro cytotoxicity was measured by the viability of EAC cells after direct treatment of the said compounds. In in vivo study, MT81 and its structural analogue were administered (i.p.) at the two different doses (5, 7 mg MT81; 8.93, 11.48 mg Aa‐MT81/kg body weight) for 7 days after 24 hrs. of tumor inoculation. The activities were assessed using mean survival time (MST), increased life span (ILS), tumor volume, viable tumor cell count, peritoneal cell count, protein percentage and hematological parameters. Antioxidant status was determined by malondialdehyde (MDA) and reduced glutathione (GSH ) content, and by the activity of superoxide dismutase (SOD) and catalase (CA T). MT81 and its structural analogues increased the mean survival time, normal peritoneal cell count. They decreased the tumor volume, viable tumor cell count, hemoglobin percentage and packed cell volume. Differential counts of WBC, total counts of RBC & WBC that altered by EAC inoculation, were restored in a dose‐dependent manner. Increased MDA and decreased GSH content and reduced activity of SOD, and catalase in EAC bearing mice were returned towards normal after the treatment of MT81 and its structural analogue. Being less toxic than parent toxin MT81, the structural analogue showed more prominent antineoplastic activities against EAC cells compared to MT81. At the same time, both compounds exhibit to some extent antioxidant potential for the EAC‐bearing mice.
Reactive Oxygen Species and Age‐Related Genes p66Shc, Sirtuin, FoxO3 and Klotho in Senescence
Authors: Afanas′ev Igor
Published: August 2010

Reactive oxygen species (ROS) superoxide and hydrogen peroxide perform important signaling functions in many physiological and pathophysiological processes. Cell senescence and organismal age are not exemptions. Aging‐regulating genes p66shc, Sirtuin, FOXO3a and Klotho are new important factors which are stimulated by ROS signaling. It has been shown that ROS participate in initiation and prolongation of gene‐dependent aging development. ROS also participate in the activation of protein kinases Akt/PKB and extracellular signal‐regulated kinase ERK, which by themselves or through gene activation stimulates or retards cell senescence. Different retarding/stimulating effects of ROS might depend on the nature of signaling species—superoxide or hydrogen peroxide. Importance of radical anion superoxide as a signaling molecule with “super‐nucleophilic” properties points to the possibility of the use of superoxide scavengers (SOD mimetics, ubiquinones and flavonoids) for retarding the development of aging.
Multifaceted Approach to Resveratrol Bioactivity: Focus on Antioxidant Action, Cell Signaling and Safety
Authors: Kovacic Peter , Somanathan Ratnasamy
Published: August 2010

Resveratrol (RVT) is a naturally occurring trihydroxy stilbene that displays a wide spectrum of physiological activity. Its ability to behave therapeutically as a component of red wine has attracted wide attention. The phenol acts as a protective agent involving various body constituents. Most attention has been given to beneficial effects in insults involving cancer, aging, cardiovascular system, inflammation and the central nervous system. One of the principal modes of action appears to be as antioxidant. Other mechanistic pathways entail cell signaling, apoptosis and gene expression. There is an intriguing dichotomy in relation to pro‐oxidant property. Also discussed are metabolism, receptor binding, rationale for safety and suggestions for future work. This is the first comprehensive review of RVT based on a broad, unifying mechanism.
Advanced Glycation end Products, Oxidative Stress and Diabetic Nephropathy
Authors: Yamagishi Sho-ichi , Matsui Takanori
Published: August 2010

About 246 million people worldwide had diabetes in 2007. The global figure of people with diabetes is projected to increase to 370 million in 2030. As the prevalence of diabetes has risen to epidemic proportions worldwide, diabetic nephropathy has become one of the most challenging health problems. Therapeutic options such as strict blood glucose and blood pressure controls are effective for preventing diabetic nephropathy, but are far from satisfactory, and the number of diabetic patients on end‐stage renal disease is still increasing. Therefore, a novel therapeutic strategy that could halt the progression of diabetic nephropathy should be developed. There is accumulating evidence that advanced glycation end products (AGEs), senescent macroprotein derivatives formed at an accelerated rate under diabetes, play a role in diabetic nephropathy via oxidative stress generation. In this paper, we review the pathophysiological role of AGEs and their receptor (RAGE)‐oxidative stress system in diabetic nephropathy.
Release of B Cell‐Activating Factor of the TNF Family in Bronchoalveolar Lavage from Behçet Disease with Pulmonary Involvement
Authors: Hamzaoui Agnès , Chelbi Hanene , Hai Sassi Fayçal , Hamzaoui Kamel
Published: August 2010

Pulmonary artery aneurysms, arterial and venous thrombosis, pulmonary infarction, recurrent pneumonia, bronchiolitis obliterans organized pneumonia, and pleurisy are the main features of pulmonary involvement in Behçet disease. The objective of this study was to investigate the production of B‐cell‐activating factor of the TNF family (BAFF), an important regulator of B‐cell survival and immunoglobulin class‐switch recombination, in bronchoalveolar lavage (BAL) fluid from BD patients having pulmonary manifestation. Bronchoalveolar lavage (BAL) was performed in 15 BD patients with pulmonary manifestation and 18 BAL from healthy controls. Concentrations of B‐cell‐active cytokines, including BAFF, IL‐6 and IL‐13, were measured by using specific ELISA and cytometric bead array assays. Levels of BAFF protein were significantly increased in BAL fluid from active BD (109 ± 21.78 pg/mL) compared with those oh healthy controls (4.83 ± 1.75 pg/mL; p < 0.0001). In the BAL fluid, BAFF levels were significantly correlated with absolute numbers of total cells (r = 0.823; p < 0.0001), lymphocytes (r = 0.709; p < 0.0001), neutrophils (r = 0.809; p < 0.0001) and macrophages (r = 0.742; p < 0.0001). Normalization to albumin indicated that BAFF production occurred locally in the airways. BAFF levels were also significantly correlated with the other B‐cell‐activating cytokines IL‐6 (r = 0.882, p < 0.001) and IL‐13 (r = 0.659, p < 0.001). The antigen‐induced production of BAFF in the lung of active BD with pulmonary manifestations might contribute to immunoglobulin synthesis by B‐cells. The cells residing in the lung might affect each other through BAFF.
A Novel Dietary Supplement Containing Multiple Phytochemicals and Vitamins Elevates Hepatorenal and Cardiac Antioxidant Enzymes in the Absence of Significant Serum Chemistry and Genomic Changes
Authors: Bulku Elida , Zinkovsky Daniel , Patel Payal , Javia Vishal , Lahoti Tejas , Khodos Inna , Stohs Sidney J. , Ray Sidhartha D.
Published: August 2010

A novel dietary supplement composed of three well‐known phytochemicals, namely, Salvia officinalis (sage) extract, Camellia sinensis (oolong tea) extract, and Paullinia cupana (guarana) extract, and two prominent vitamins (thiamine and niacin) was designed to provide nutritional support by enhancing metabolism and maintaining healthy weight and energy. The present study evaluated the safety of this dietary supplement (STG; S, sage; T, tea; G, guarana) and assessed changes in target organ antioxidant enzymes (liver, kidneys and heart), serum chemistry profiles and organ histopathology in Fisher 344 rats. Adult male and female Fisher 344 rats were fed control (no STG) or STG containing (1X and 7X, 1X = daily human dose) diets and sacrificed after 2 and 4 months. Serum chemistry analysis and histopathological examination of three vital target organs disclosed no adverse influence on protein, lipid and carbohydrate profiles, genomic integrity of the liver and/or the tissue architecture. However, analysis of the most important antioxidant components in the liver, kidney and heart homogenates revealed a dramatic increase in total glutathione concentrations, glutathione peroxidase and superoxide dismutase enzyme activities. Concomitantly, oxidative stress levels (malondialdehyde accumulation) in these three organs were less than control. Organ specific serum markers (ALT/AST for the liver; CPK/AST/LDH for the heart; BUN/creatinine for kidneys) and the genomic integrity disclosed no STG‐induced alteration. Some of the serum components (lipid and protein) showed insignificant changes. Overall, STG‐exposed rats were more active, and the results suggest that STG exposure produces normal serum chemistry coupled with elevated antioxidant capacity in rats fed up to seven times the normal human dose and does not adversely influence any of the vital target organs. Additionally, this study reiterates the potential benefits of exposure to a pharmacologically relevant combination of phytochemicals compared to a single phytochemical entity.
Wnt1 Neuroprotection Translates into Improved Neurological Function during Oxidant Stress and Cerebral Ischemia Through AKT1 and Mitochondrial Apoptotic Pathways
Authors: Chong Zhao Zhong , Shang Yan Chen , Hou Jinling , Maiese Kenneth
Published: August 2010

Although essential for the development of the nervous system, Wnt1 also has been associated with neurodegenerative disease and cognitive loss during periods of oxidative stress. Here we show that endogenous expression of Wnt1 is suppressed during oxidative stress in both in vitro and in vivo experimental models. Loss of endogenous Wnt1 signaling directly correlates with neuronal demise and increased functional deficit, illustrating that endogenous neuronal Wnt1 offers a vital level of intrinsic cellular protection against oxidative stress. Furthermore, transient overexpression of Wnt1 or application of exogenous Wnt1 recombinant protein is necessary to preserve neurological function and rescue neurons from apoptotic membrane phosphatidylserine externalization and genomic DNA degradation, since blockade of Wnt1 signaling with a Wnt1 antibody or dickkopf related protein 1 abrogates neuronal protection by Wnt1. Wnt1 ultimately relies upon the activation of Akt1, the modulation of mitochondrial membrane permeability, and the release of cytochrome c to control the apoptotic cascade, since inhibition of Wnt1 signaling, the phosphatidylinositol 3‐kinase pathway, or Akt1 activity abrogates the ability of Wnt1 to block these apoptotic components. Our work identifies Wnt1 and its downstream signaling as cellular targets with high clinical potential for novel treatment strategies for multiple disorders precipitated by oxidative stress.
Oxidative Stress in Fetal Distress: Potential Prospects for Diagnosis
Authors: Raičević Saša , Čubrilo Dejan , Arsenijević Slobodan , Vukčevic Gordana , Živković Vladimir , Vuletić Milena , Barudžić Nevena , Andjelković Nebojša , Antonović Olga , Jakovljević Vladimir
Published: August 2010

Our aim was to investigate the relation between fetal distress and oxidative stress. Fetal distress was associated with increased concentration of superoxide in the fetal blood and with significant increase of the level of H2O2 in both maternal and fetal blood. The activity of superoxide dismutase was increased roughly sixfold (p < 0.01) in the maternal [7330 ± 2240 U/g of hemoglobin in controls (C) and 36811 ± 16862 U/g in fetal distress (FD)] and fetal blood (C: 5930 ± 2641 U/g; FD: 41912 ± 17133 U/g). In contrast, fetal distress was related to a considerable decrease of catalase activity in both maternal (C: 26011 ± 8811 U/g; FD: 7212 ± 1270 U/g) and fetal blood (C: 37194 ± 9191 U/g; FD: 6173 ± 1965 U/g). From this we concluded that in fetal distress, the maternal and fetal bloods are exposed to superoxide‐ and H2O2‐mediated oxidative stress, which could be initiated by hypoxic conditions in the fetal blood and placenta. A tremendous increase/decrease of the activities of superoxide dismutase/catalase in the blood of women bearing a distressed fetus in comparison to healthy subjects implies that the assessment of superoxide dismutase/catalase activity could be of use for establishing a timely and accurate ante‐ or intrapartum diagnosis of fetal distress.
Acetaldehyde Adducts in Alcoholic Liver Disease
Authors: Setshedi Mashiko , Wands Jack R. , de la Monte Suzanne M.
Published: August 2010

Chronic alcohol abuse causes liver disease that progresses from simple steatosis through stages of steatohepatitis, fibrosis, cirrhosis, and eventually hepatic failure. In addition, chronic alcoholic liver disease (ALD), with or without cirrhosis, increases risk for hepatocellular carcinoma (HCC). Acetaldehyde, a major toxic metabolite, is one of the principal culprits mediating fibrogenic and mutagenic effects of alcohol in the liver. Mechanistically, acetaldehyde promotes adduct formation, leading to functional impairments of key proteins, including enzymes, as well as DNA damage, which promotes mutagenesis. Why certain individuals who heavily abuse alcohol, develop HCC (7.2–15%) versus cirrhosis (15–20%) is not known, but genetics and co‐existing viral infection are considered pathogenic factors. Moreover, adverse effects of acetaldehyde on the cardiovascular and hematologic systems leading to ischemia, heart failure, and coagulation disorders, can exacerbate hepatic injury and increase risk for liver failure. Herein, we review the role of acetaldehyde adducts in the pathogenesis of chronic ALD and HCC.
Forever Young: Mechanisms of Natural Anoxia Tolerance and Potential Links to Longevity
Authors: Krivoruchko Anastasia , Storey Kenneth B.
Published: August 2010

While mammals cannot survive oxygen deprivation for more than a few minutes without sustaining severe organ damage, some animals have mastered anaerobic life. Freshwater turtles belonging to the Trachemys and Chrysemys genera are the champion facultative anaerobes of the vertebrate world, often surviving without oxygen for many weeks at a time. The physiological and biochemical mechanisms that underlie anoxia tolerance in turtles include profound metabolic rate depression, post‐translational modification of proteins, strong antioxidant defenses, activation of specific stress‐responsive transcription factors, and enhanced expression of cyto‐protective proteins. Turtles are also known for their incredible longevity and display characteristics of “negligible senescence.” We propose that the robust stress‐tolerance mechanisms that permit long term anaerobiosis by turtles may also support the longevity of these animals. Many of the mechanisms involved in natural anoxia tolerance, such as hypometabolism or the induction of various protective proteins/pathways, have been shown to play important roles in mammalian oxygen‐related diseases and improved understanding of how cells survive without oxygen could aid in the understanding and treatment of various pathological conditions that involve hypoxia or oxidative stress. In the present review we discuss the recent advances made in understanding the molecular nature of anoxia tolerance in turtles and the potential links between this tolerance and longevity.
Evidence for the effectiveness of the Montreal Protocol to protect the ozone layer
Authors: Mäder J. A. , Staehelin J. , Peter T. , Brunner D. , Rieder H. E. , Stahel W. A.
Published: August 2010

Abstract. The release of man-made ozone depleting substances (ODS, including chlorofluorocarbons and halons) into the atmosphere has lead to a near-linear increase in stratospheric halogen loading since the early 1970s, which started to level off after the mid-1990s and then to decline, in response to the ban of many ODSs by the Montreal Protocol (1987). We developed a multiple linear regression model to test whether this has already a measurable effect on total ozone values observed by the global network of ground-based instruments. The model includes explanatory variables describing the influence of various modes of dynamical variability and of volcanic eruptions. In order to describe the anthropogenic influence a first version of the model contains a linear trend (LT) term, whereas a second version contains a term describing the evolution of equivalent effective stratospheric chlorine (EESC). By comparing the explained variance of these two models we evaluated which of the two terms better describes the observed ozone evolution. For a significant majority of the stations, the EESC proxy fits the long term ozone evolution better than the linear trend term. Therefore, we conclude that the Montreal Protocol has started to show measurable effects on the ozone layer about twenty years after it became legally binding.
Artificial Intelligence Approach to Energy Management and Control in the HVAC Process: An Evaluation, Development and Discussion
Authors: Zhou Hong , Rao Ming , Chuang Karl T.
Published: August 2010

Computer control technology in heating, ventilating and air conditioning (HVAC) systems has evolved in two technical phases: central control and direct digital control (DDC) with central monitoring function. Many control strategies have been developed for energy conservation in HVAC energy management and control systems (EMCS) and these are reported in the literature. An artificial intelligence approach to the EMCS in HVAC process is proposed in this paper. Two real time expert systems for energy‐saving operation and indoor setting are developed and integrated with an adaptive control strategy. Further, a configuration of an integrated intelligent system for intelligent building management is proposed, in which building management functions are coordinated by a meta‐system. The applications of artificial intelligence (AI) techniques in a HVAC process give a new avenue for the development of EMCS in the HVAC industry.
Kinetics of Synthesizing Dibutanoxymethane at Very High Alkaline Concentration by Phase Transfer Catalysis
Authors: Wang M.‐L. , Chang S.‐W.
Published: August 2010

The reaction of dibromomethane and 1‐butanol to synthesize dibutanoxymethane in a very high alkaline concentration of KOH (i.e. large amount of solid KOH/organic solvent) by phase transfer catalysis was studied. Only one unique final product with two butanoxide substituents was observed in the organic phase, thus indicating a very fast rate for the second reaction. The reaction rate was significantly enhanced by adding a small amount of quaternary ammonium salt. Only a pseudo‐first‐order rate law can be applied to describe the reaction at a very high concentration of KOH. This peculiar phenomenon was explained by the limitation of the chemical reaction equilibrium in the aqueous phase as the controlling step at a low KOH concentration, and the reaction in the organic phase as the controlling step at a high KOH concentration. The experimental results indicate that the mass‐transfer resistance of the active catalyst ((C4H9)4N+ ‐OC4H9; QOR) is negligible, compared with the reactions in the two phases. When using TBAB as the catalyst, the only way to increase the product yield is by the use of a solvent with appropriate polarity and a small amount of water at a very high alkaline KOH content.
Bioflocculation of Hematite Suspensions with Products from Yeast Cell Rupture
Authors: Schneider I.A.H. , Misra M. , Smith R. W.
Published: August 2010

The flocculation of −38 m̈m hematite aqueous suspensions by the yeast Candida parapsilosis, and by products derived from the ultrasonic rupture of this microorganism was studied. Results obtained are compared to the flocculation of comparable suspensions by cooked corn starch and a polyacrylamide (average molecular weight 106.
Development of Correlations for Mass Transfer Coefficient in Ultrafiltration Systems
Authors: De S. , Bhattacharjee S. , Bhattacharya P. K.
Published: August 2010

Correlations for the determination of the mass transfer coefficient in ultrafiltration systems are developed. This was done by the inclusion of a new dimensionless number relevant for ultrafiltrative systems; namely, the Peclet number based on the test cell experimental flux. The incorporation of this group altered the estimate of the mass transfer coefficient significantly. The development of the present correlations was done by regression analysis over the experimental data obtained in our laboratory as well as those reported in the literature for both laminar and turbulent regimes. Experimental estimates of mass transfer coefficients in a number of UF devices using various feed solutions were used to develop the correlations. Detailed statistical analyses were carried out to test the adequacy of the developed correlations and the model parameters. Correlations are also developed for an industrial effluent (black liquor) for different flow configurations and regimes. Values of mass transfer coefficients obtained from the developed correlations were also compared with those obtained from the standard correlations and velocity variation technique. Developed correlations should be useful for ultrafiltration system design.
Composite Membrane Systems for High‐Temperature Chemical Catalytic Processing
Authors: Gobina E. , Hou K.
Published: August 2010

A study has been carried out to assess the relative performance characteristics of dense and porous composite membranes for high‐temperature alkane dehydrogenation. Rigorous two‐dimensional mathematical models have been developed and applied to describe the various processes of transport and chemical reaction taking place in these complex novel reactor systems. The orthogonal collocation technique has been used to simulate the industrially important dehydrogenation of ethylbenzene to styrene as the model reaction. The results have clearly demonstrated superior performance of dense composite membranes below a thickness of 50 μm. However, above this thickness porous composite systems are preferable in terms of conversion enhancement, but all the systems depict identical performance at a separation layer thickness of 150 μm. The performance of the systems is also studied by obtaining the conversion level as a function of the contact time parameter using various feed compositions. These findings have demonstrated that exclusive hydrogen permeability is important, provided the separation layer thickness is not too great.
Diffusional Analysis during Air Drying of a Starch Food System
Authors: Mcminn W. A. M. , Macgee T. R. A.
Published: August 2010

Starch, as a major component of several food products of plant origin, was used as a simulant for investigation of the basic physical and engineering properties of particulate and porous foods. An experimental tunnel dryer was used to investigate the drying‐rate and temperature profiles developed within potato starch gel cylinders during convective drying. The experimental diffusional data were characterised using Fick's second law and an empirical model was developed to predict the effective moisture diffusivity as a function of air temperature, air velocity and sample radius. The experimental and predicted results were in good agreement. The temperature distribution developed within the sample were measured and presented as a function of both drying time and dimensionless distance.
Limitations on the Applications of Advanced Process Control in Mineral Processing Operations
Authors: Tade M. O. , To L. C. , Ray M. S.
Published: August 2010

The development of advanced control theory has received considerable attention in academia over the past two decades, and extensive applications can be found in the literature for systems other than industrial process control, for example, vehicle control, robot control, electrical machines and systems control. Applications in the process industry are gradually increasing, see for example [I]. However, relatively few industrial examples of advanced control applications have been reported for the mineral processing industry. A review of the current status of modern control as applied to mineral processing operations (MPO) is given in this paper. The limitations of these techniques which have caused reluctance in their acceptance by the industry are discussed. Two case studies of our experiences in applying modern control techniques in alumina refineries are presented. Insights are also provided on how to bridge the gap between academia and industrial practice of process control in this area.
Technical and Economic Considerations of Solid Oxide Fuel Cell Systems
Authors: McCahey S , McMullan J. T. , Williams B. C.
Published: August 2010

The ECLIPSE process simulator has successfully evaluated the technical and economic performance of a number of systems based on a natural gas fed Solid Oxide Fuel Cell (SOFC). These systems differ in their approach to reforming of the natural gas feedstock and in their use of anode gas recycle. The most efficient system is the direct internal reforming SOFC with an efficiency of 48.0% giving C02emissions of 420 g/kWh. The indirect internal reforming and the external reforming SOFC have efficiencies about 3.5 to 4 percentage points lower. The total energy efficiencies vary between 87.2% and 91.0% and if the useful, high grade heat could be converted into electricity via steam turbines then the electrical efficiency increases by about 10 % points. The effect of anode gas recycle is to improve the electrical efficiency by on average 7.5 % points and to reduce C02emissions by 15%.

Compared to conventional power generation technologies, the efficiency of, and C02emissions from, a direct internal reforming SOFC are vastly superior to the small scale gas turbine and gas engine systems and slightly better than the large scale gas turbine combined cycle systems. However, from the point of view of cost of electricity, for the SOFC to compete with the small scale systems the SOFC capital cost must be reduced to less than either 500/kWe with a lifetime of greater than 15 years or 600/kWe with a lifetime of greater than 20 years. For SOFC systems to compete with large scale gas turbine combined cycle systems they must be used in a combined heat and power configuration with a similar capital cost as above. Current estimates for SOFC costs are around 1000/kWe with an uncertain lifetime. Therefore, at this stage, the economic viability of SOFC power generation systems depends on cost reduction and lifetime enhancement, probably via materials development and operating temperature reduction.
The Development and Characterisation of Sorbents from Irish Sphagnum Moss Peat
Authors: Whitten L. J. , Allen S. J.
Published: August 2010

A range of carbon chars was produced from sphagnum moss peat by heating in a furnace with a reduced oxygen atmosphere. A series of heating times and temperatures were selected for the preparation of the chars. Comparative porosity and surface area studies, based on nitrogen sorption isotherms and mercury porosimetry data, were carried out to characterise the chars. Further characterisation studies were condućted by electron microscopy techniques. Optimum charring conditions, yielding maximum surface area for N2 adsorption, were observed at a charring temperature of 800°C and charring time 30 minutes. Using the optimum charring conditions, a further series of chars was produced. Prior to charring the raw peat was chemically pre‐treated with a range of metal salt solutions of varying percentage concentration. The resulting chars were characterised as above. The adsorptive capacity of these chars for N2 was investigated on the Sorptomatic 1900 (Fisons Instruments). The adsorption isotherms were compared to the standard isotherms of Langmuir. Adsorbate uptake was seen to vary with surface area availability, pore volume, pore type and the nature of the adsorbate.
A Revised Analysis of the Effect of Surfactants on Two‐Phase Phenomena in Horizontal Air‐Water Pipe Flow
Authors: Spedding P. L. , Hand N. P.
Published: August 2010

Flow regimes, hold‐up and pressure loss measurements in two‐phase air‐water co‐current horizontal flow have shown that the effect of surfactant was to: a. suppress the formation of ripples or gravity waves; b. progressively extend the range of the smooth stratified pattern at the expense of the ripple flow regime, as the gas rate was increased; c. increase the liquid hold‐up above that for water alone over the wavy regimes from the top end of the smooth stratified pattern to the onset of film‐plus‐droplet flow, and there was a corresponding reduction in pressure loss. The mechanism responsible for the suppression of waves resulted in a reduction in the ability of the gas to scour out the liquid. The fundamental cause for these effects was linked to local variations in surface tension as the surface film on the liquid was alternatively expanded and compressed by the ripples. Additional effects of surfactant at other flow conditions were that: d. drag reductions occurred in the slug and plug regimes with the surfactant affecting the liquid slug nose regions; e. drag reduction also occurred in the annular regime at high gas and liquid flow rates, caused by the damping of waves at the base of the annular film. These results help explain a number of apparent anomalies presented in the literature.
Recent Developments in Photocatalysis
Authors: Howe R. F.
Published: August 2010

This article reviews some recent developments in the area of photocatalysis. These include the development of methods for preparing nanocrystalline (Q‐sized) TiO2, the doping and promotion of titania to improve its photoreactivity, recent studies of reaction mechanisms, the introduction of other oxide photocatalysts, and recent advances in the design of reactors for photocatalysis. It is concluded that practical implementation of photocatalysis, particularly in environmental applications, is now close to reality.
Modeling of Fluidized Bed Reactors for the Polymerization Reaction of Ethylene and Propylene
Authors: Abasaeed A. E. , Al‐Zahrani S. M.
Published: August 2010

Polyethylene and polypropylene are used worldwide due to their versatile physical and chemical properties. A simplified dynamic model is developed to describe the polymerization reactions in a fluidized bed reactor. The effect of two important operating parameters, i.e. catalyst injection rate and superficial velocity, on the performance of the unit are investigated. Qualitatively as well as quantitatively different bifurcation diagrams are obtained for each case. However, in both cases, operation of the reactor is confined to the stable low monomer conversion region due to polymer softening temperature limitation.
Removal of Lead(II) by Mordenites
Authors: Dai S. , Kato Y. , Guang D. , Amal R.
Published: August 2010

Batch studies were conducted to investigate the removal of Pb2+ using mordenite. Effects of lead concentration, solution pH, particle size and dosage of mordenite on the removal kinetics and the removal capacity of lead were investigated. It was found that the main removal mechanism was ion exchange, with Na, Ca, and K as major exchange cations. The exchange kinetics and the exchange capacity of lead with the cations in mordenite increased as the lead concentration increased. The solution pH affected the exchange rate but not the lead exchange capacity. The reaction rate at pH 5 was faster than that at pH 3. As the particle size of mordenite decreased, the reaction rate increased. The exchange rate of lead also increased as the mordenite dosage increased. A significant removal of lead by mordenite was observed. For a lead concentration of 3 ppm, 99% of the lead was removed, and for a high lead concentration (200ppm), 70% lead removal can still be achieved. It can be concluded that mordenite has a great potential to remove lead from wastewaters.
Partial Oxidation of Propylene Over Hydrophobic Catalysts in a Slurry Reactor
Authors: Liang W. , Chuang K. T. , Zhou B.
Published: August 2010

Propylene partial oxidation over hydrophobic catalysts was studied in a slurry reactor. Due to the hydrophobicity of the catalyst, a direct reaction mechanism between the gas phase reactants and the catalyst was proposed for the reaction. The experimental results and the predictions based on this model are consistent, indicating that the proposed mechanism is reasonable for propylene oxidation over the hydrophobic catalyst. Also, due to the hydrophobicity and the low density of the catalyst, it is observed that there is non‐uniform catalyst particle distribution in the reactor. The effect of the catalyst particle non‐uniformity on the reaction is discussed and predictions are made based on the model. The effect of different operating conditions for the slurry reactor on propylene conversion, selectivity to CO2, and acrylic acid yield have been studied. A comparison between results obtained using the hydrophobic and hydrophilic catalysts shows the advantage of using the hydrophobic rather than hydrophilic catalysts for propylene partial oxidation in the slurry reactor, which is attributable to the direct reaction mechanism over the hydrophobic catalysts.
The Production and Characterisation of Activated Carbons: A Review
Authors: Allen S. J. , Whitten L. , Mckay G.
Published: August 2010

The uses of active carbons and carbon chars for liquid and gas phase applications has been presented. Their application for decolourising, water treatment, solvent recovery, military uses, nuclear industry, air purification, domestic uses, precious metal recovery and catalysis, have been outlined. A detailed review of the production and manufacture of activated carbons from a wide range of carbonaceous sources is given. Methods of activation are discussed based on a range of chemicals and how these chemicals influence surface activity, pore size and pore distribution. The techniques for characterising activated carbons are reviewed in detail and include porosimetry, sorptometry, topography, pore size distribution, isotherms and surface area measurements. The specific results of some active carbons derived from lignocellulosic materials (peat and lignite) are also presented.
In‐situ Regeneration of Phenol‐Saturated Activated Carbon Using Ethanol
Authors: Matheickal J. T. , Yu Q. , Linden J.
Published: August 2010

In‐situ regeneration of spent activated carbon can be a more cost effective alternative than the thermal regeneration method. This paper studies the suitability of ethanol for the regeneration of a granular activated carbon (Filtrasorb‐400), that was saturated with phenol from wastewater. Ethanol is less hazardous, completely miscible with water and offers convenient solvent recovery. The adsorption capacity of fresh activated carbon for phenol was found to be 208 mg g−1. The recovery of phenol adsorption capacity of the carbon, operated cyclically using a sequence of phenol adsorption, desorption with ethanol, and rinsing with water, was determined in both batch and fixed‐bed processes. The kinetics of the regeneration process were also studied. In the fixed‐bed process, the regeneration efficiency by using ethanol was 98% after the first regeneration cycle and 94% after the third regeneration cycle. The corresponding values for batch operations were 89% and 85%, respectively. The kinetics of regeneration in batch processes were fast, and 90% of the total regeneration was complete within 30 minutes. The results from this study indicate that ethanol could be used to regenerate granular activated carbon in‐situ with only marginal loss of adsorption capacity.
Dissolution of Phosphate Rock by Mixtures of Sulfuric and Phosphoric Acid
Authors: Jamialahmadi M. , Emam S. H. , Müller‐Steinhagen H.
Published: August 2010

The dihydrate process for the production of phosphoric acid is increasingly important as the basis for phosphate fertilizer plants. The process involves dissolution of phosphate rock in an aqueous mixture of phosphoric and sulfuric acid and subsequent crystallization of calcium sulfate dihydrate from the product phosphoric acid solution. In this study the mechanisms of dissolution of phosphate rock are studied using reagent grade and plant acids. The effects of various operating parameters such as temperature, particle size and excess sulfuric acid concentration on the rate of dissolution of rock are investigated. The results show that the dissolution of the rock occurs in two stages of different rates. Initially, the dissolution process is fast and is controlled by chemical reaction between rock and acid. In the second stage, when the particles are coated by calcium sulfate dihydrate the dissolution process is slow and controlled by mass transfer of acid through the coating layer.
Vertical Two Phase Flow
Authors: Woods G. S. , Spedding P. L. , Watterson J. K. , Raghunathan R. S.
Published: August 2010

Data are presented on flow regimes, holdup and pressure drop for vertical co‐current two phase flow in a 0.026 m i.d. pipe. A universal flow regime map was not possible but flow regime transitional equations were developed for the slug to churn, churn to semi‐annular, semi‐annular to annular and annular to annular ripple boundaries. Holdup was shown to be predicted by the Nicklin [15] relation for intermittent regimes and the Spedding‐Chen [16] relation for annular flows. Pressure drop in the slug regime was shown to be subjected to an uplifting effect due to liquid being held in the wake of the rising gas bubble. Pressure loss prediction was possible for bubble, slug and annular regimes only.
Reaction Hysteresis: A New Cause of Output Multiplicity in Reactive Distillation
Authors: Sneesby M. G. , Tadé M. O. , Smith T. N.
Published: August 2010

Jacobsen and Skogestad (1991) described two causes of multiple steady states in binary distillation via an analysis of the fundamental equations of the equilibrium stage model for distillation processes. Later, Bekiaris and Morari (1993) described multiple steady states in azeotropic distillation using a geometric analysis based on the conditions of perfect fractionation (infinite number of stages and infinite reflux ratio). Commercial process simulators (Pro/IITM and Speed UpTM) were used to investigate multiple steady states in reactive distillation via the construction of bifurcation diagrams (the locus of solutions obtained by varying a single continuation parameter). These results indicate that the mechanisms described by Jacobsen and Skogestad (1991) and Bekiaris and Morari (1993) are each pertinent to reactive distillation processes. However, some examples of multiple steady states cannot be adequately explained with the available explanations and a fourth cause of output multiplicity, applicable only to hybrid reactive distillation, was proposed. Supplementary simulation studies indicate that the proposed explanation is sound.
The Use of Metallocene Catalysed Polyethylene as a Blend Material in Blown Film Extrusion
Authors: Beagan C. M. , Mcnally G. M. , Murphy W. R.
Published: August 2010

Metallocene catalysed polyethylenes are the latest addition to the polyethylene family and are reported to have superior mechanical properties over conventional polyethylenes. This paper sought to investigate the effect of blending these materials with conventional low density polyethylene for use in thin films, suitable as packaging materials and produced by the blown film process. Two grades of Metallocene catalysed polyethylene were used in the study. Films containing increasing percentages of these resins were produced at various processing conditions and their mechanical properties considered. These films were then characterised using Differential Scanning Calorimetry and Dynamic Mechanical Thermal Analysis techniques. This work showed that increasing the percentage of metallocene catalysed polyethylene in a low‐density polyethylene film improved the mechanical properties of the resultant film.
The Relevance of Predictive Techniques to Industrial Combustion and Heat Transfer Problems
Authors: Mullinger P. J.
Published: August 2010

Control of fire is the very foundation of our industrialised society, and whilst most processes will continue to rely on fossil fuel combustion for the foreseeable future, a wide range of organic wastes is being used, and more can potentially be used, to supplement fossil fuels. Landfilling waste liquids such as cleaning solvent, used lubricating oil and hydrocarbon wastes from various manufacturing processes potentially pollute the soil, water courses and the air (by evaporation). By comparison the use of waste liquids as fuel can result in significant environmental benefits and provide cost savings for the plant. Burning these liquids eliminates these sources of pollution and recovers heat for the process ‐ hence saving fossil fuels, such as coal, natural gas and fuel oil, for the future. An effective and low cost technique is to burn wastes directly in suitable process plants. To utilise these resources effectively however requires a good understanding of the combustion and heat transfer processes in the plant to ensure production capacity and emissions are not adversely affected. Successful application of wastes as supplementary fuel requires careful analysis of the effect on plant operation and the environmental impact well ahead of permit applications, or a trial burn. The complexity of the combustion and heat transfer processes make such an analysis technically difficult, but no less essential.
Large‐Scale Structure in Turbulent Diffusion Flames ‐ Evidence, Implications, Origins
Authors: Mungal M. G.
Published: August 2010

This work reviews some evidence for the existence of large‐scale structures in turbulent diffusion flames, at low and high Reynolds numbers, for free jets and jets in crossflow over a range of buoyancy conditions. The striking differences between the velocity field and the scalar field will be highlighted and implications for mixing and reaction are explored. The origins of these differences are discussed by analogy to simple large‐scale wave motions in the velocity field leading to complex mixing patterns in the scalar field.