Fermentation Kinetics for the Production of Ethanol by Immobilized Yeast Cells (Biomass).

Using immobilized microorganisms for ethanol fermentation from biomass has attracted much interest in recent years. Such a system offers unique advantages over traditional fermentation processes, e.g. higher productivities, higher ethanol tolerance, and continuous operation. The goals of this research were as follows: (1) to study the growth behavior of immobilized yeast cells and diffusion characteristics of the support, (2) to develop immobilization technology and improve the physical properties of the support, (3) to develop a generally applicable parameter estimation method for the complex reaction kinetics of immobilized biocatalysts, and (4) to determine ethanol fermentation kinetics using immobilized yeast cells. In intial studies on the immobilization of yeast cells on agar, the formation of an active layer on and near the surface of the support was observed. The thickness of this layer was found to be constant regardless of the size or shape of the support. It was also independent of substrate concentration. Both the growth of cells and the production of carbon dioxide reduced the diffusional resistance of the gel, an indication that the gel network underwent significant structural changes. A new method was developed for treating agar or carrageenan gel with polyacrylamide to form a more rigid support. The size and shape of the gel beads were unaffected by this treatment, but the physical strength was much improved. The productivities achieved for ethanol production were as high as or higher than those reported in the literature. A method was also developed for estimating intrinsic kinetic parameters for reaction systems of immobilized cells and enzymes under the influence of internal and external diffusion resistances. The technique was found generally applicable to any reaction system which follows either Michaelis-Menten kinetics with product and/or substrate inhibition, or any exponential reaction rate expression. The method employs orthogonal collocation into which Powell\u27s nonliner least square minimization algorithm is incorporated. Finally, the above method for kinetic parameter estimation was successfully applied to ethanol fermentation. Statistical analysis showed that Monod\u27s model, both with substrate and product inhibition, and with product inhibition alone, fitted the experimental data

Effect of relative humidity and temperature on moisture sorption and stability of sodium bicarbonate powder

Abstract The effects of relative humidity and temperature on moisture sorption rate and stability profile of sodium bicarbonate powder exposed to various storage conditions were investigated using gravimetrical and acid-titration methods. In the study, samples were placed in desiccators, which contained various saturated salt solutions to generate desired levels of relative humidity, denoted as RH, ranging from 30 -93% RH. The weight of each sample was determined periodically. The results show that both the temperature and relative humidity are key factors in moisture sorption isotherm and decomposition kinetics. The threshold relative humidity RH th is defined as the relative humidity above which sodium bicarbonate powder starts to rapidly gain weight. The critical relative humidity RH c is defined as the relative humidity above which sodium bicarbonate powder either starts to rapidly gain weight or starts to rapidly hydrolyze (resulting in losing weight). The moisture sorption isotherm shows an unusual phenomenon at high RH, where the weight of the sodium bicarbonate powder either increases or decreases with time, depending on the storage temperature. When the powder is exposed to a lower temperature and high humidity level (e.g. at 25°C and 93% RH), the weight increases rapidly, due to the fact that the relative humidity exceeds the RH th at this temperature. On the other hand, when the powder is exposed to higher temperature and high humidity levels (e.g. at 40°C, 89% RH and at 55 o C, 82% RH), the weight of the powder decreases with time since the relative humidity is below the RH th at these temperature levels and the decomposition rate is higher than the moisture sorption rate. The decomposition of sodium bicarbonate results in the release of carbon dioxide. The values of RH c at 25 and 40°C were determined to be between 76 and 88% RH and between 48 and 75% RH, respectively. The accurate moisture content and the stability profiles of sodium bicarbonate were determined using a titration-drying-titration procedure. The results of determination show that sodium bicarbonate powder is stable below 76% RH at 25°C and below 48% RH at 40°C, respectively

Deranged Bioenergetics and Defective Redox Capacity in T Lymphocytes and Neutrophils Are Related to Cellular Dysfunction and Increased Oxidative Stress in Patients with Active Systemic Lupus Erythematosus

Urinary excretion of N-benzoyl-glycyl-Nε-(hexanonyl)lysine, a biomarker of oxidative stress, was higher in 26 patients with active systemic lupus erythematosus (SLE) than in 11 non-SLE patients with connective tissue diseases and in 14 healthy volunteers. We hypothesized that increased oxidative stress in active SLE might be attributable to deranged bioenergetics, defective reduction-oxidation (redox) capacity, or other factors. We demonstrated that, compared to normal cells, T lymphocytes (T) and polymorphonuclear neutrophils (PMN) of active SLE showed defective expression of facilitative glucose transporters GLUT-3 and GLUT-6, which led to increased intracellular basal lactate and decreased ATP production. In addition, the redox capacity, including intracellular GSH levels and the enzyme activity of glutathione peroxidase (GSH-Px) and γ-glutamyl-transpeptidase (GGT), was decreased in SLE-T. Compared to normal cells, SLE-PMN showed decreased intracellular GSH levels, and GGT enzyme activity was found in SLE-PMN and enhanced expression of CD53, a coprecipitating molecule for GGT. We conclude that deranged cellular bioenergetics and defective redox capacity in T and PMN are responsible for cellular immune dysfunction and are related to increased oxidative stress in active SLE patients

Urinary Neutrophil Gelatinase-Associated Lipocalin Is a Potential Biomarker for Renal Damage in Patients with Systemic Lupus Erythematosus

Neutrophil gelatinase-associated lipocalin (NGAL) has been demonstrated to be a novel biomarker in acute and chronic kidney disease. We hypothesized that 24-hour urinary NGAL excretion may be a predictor for renal damage in patients with systemic lupus erythematosus (SLE). Thirty-four SLE patients with renal involvement (SLE-renal group), 8 SLE patients without renal involvement (SLE-nonrenal group), 14 patients with non-SLE autoimmune diseases (disease control or DC group), and 12 healthy volunteers (normal control or NC group) were compared for 24-hour urinary excretion of NGAL and different cytokines. We found that the 24-hour urinary NGAL excretion in the SLE-renal group was higher than that in the SLE-non-renal, DC, and NC groups. However, the excretion of interleukin-10, transforming growth factor-β1, and tumor necrosis factor-α was not different between the SLE-renal and SLE-non-renal groups. Furthermore, NGAL excretion in the SLE-renal group was correlated with serum creatinine levels and creatinine clearance, but not with the SLE Disease Activity Index score. Multivariate logistic regression analysis and receiver operating characteristic curve analysis revealed that 24-hour urinary NGAL excretion is a potential biomarker for renal damage in SLE patients, with higher sensitivity and specificity than anti-dsDNA antibody titers

Neurobiological correlates in Internet Gaming Disorder: a systematic literature review

Internet Gaming Disorder (IGD) is a potential mental disorder currently included in the third section of the latest (fifth) edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-5) as a condition that requires additional research to be included in the main manual. Although research efforts in the area have increased, there is a continuing debate about the respective criteria to use as well as the status of the condition as mental health concern. Rather than using diagnostic criteria which are based on subjective symptom experience, the National Institute of Mental Health advocates the use of Research Domain Criteria (RDoC) which may support classifying mental disorders based on dimensions of observable behavior and neurobiological measures because mental disorders are viewed as biological disorders that involve brain circuits that implicate specific domains of cognition, emotion, and behavior. Consequently, IGD should be classified on its underlying neurobiology, as well as its subjective symptom experience. Therefore, the aim of this paper is to review the neurobiological correlates involved in IGD based on the current literature base. Altogether, 853 studies on the neurobiological correlates were identified on ProQuest (in the following scholarly databases: ProQuest Psychology Journals, PsycARTICLES, PsycINFO, Applied Social Sciences Index and Abstracts, and ERIC) and on MEDLINE, with the application of the exclusion criteria resulting in reviewing a total of 27 studies, using fMRI, rsfMRI, VBM, PET, and EEG methods. The results indicate there are significant neurobiological differences between healthy controls and individuals with IGD. The included studies suggest that compared to healthy controls, gaming addicts have poorer response-inhibition and emotion regulation, impaired prefrontal cortex (PFC) functioning and cognitive control, poorer working memory and decision-making capabilities, decreased visual and auditory functioning, and a deficiency in their neuronal reward system, similar to those found in individuals with substance-related addictions. This suggests both substance-related addictions and behavioral addictions share common predisposing factors and may be part of an addiction syndrome. Future research should focus on replicating the reported findings in different cultural contexts, in support of a neurobiological basis of classifying IGD and related disorders

Economic disturbances and exchange market intervention policy

This dissertation derives the different effects that non-sterilized direct intervention, sterilized direct intervention, and indirect intervention can have in a small open economy, and evaluates the appropriate intervention policy under different circumstances. In a dynamic model with the sticky price of domestic goods, exchange market intervention affects the short-run fluctuations of the economy and the speed of adjustment to the long-run equilibrium. When the substitutability of domestic and foreign bonds is finite, the effectiveness of each type of foreign exchange market intervention depends on the source of economic disturbances and the magnitude of the parameters. An appropriate intervention policy may be evaluated in terms of modifying the short-run impacts of a disturbance and changing the speed of adjustment of the economy. Any intervention policy can reduce a depreciation of the spot real exchange rate if the long-run real exchange rate is not higher than the depreciation spot rate. But in terms of dynamic adjustments to the long-run equilibrium, indirect intervention speeds up the adjustment and sterilized direct intervention slows down the adjustment. Non-sterilized direct intervention has an ambiguous effect, depending on the values of parameters. Therefore, in most cases considered, the dominant policy is indirect intervention as large as possible, because that minimizes the impact effect and speeds up the adjustment of the economy. When the same degree of intervention is used, non-sterilized direct intervention eliminates the impact effect the most. Therefore, if non-sterilized direct intervention speeds up the adjustment of the economy, and the purpose of the government is first to minimize the impact effect and second to speed up the adjustment of the economy, non-sterilized direct intervention is preferred. Also, in the case of increased domestic demand for domestic goods, sterilized direct intervention with $\mu$ $\u3c$ 0 may speed up the adjustment of the economy and eliminate the impact effect, depending the magnitude of parameters, while other intervention policies enlarge the impact effect. Thus, the choice of an appropriate intervention policy depends on the source of economic disturbances, the values of parameters, and the priority of the government

Les Métamorphoses d'Alcofribas dans l'œuvre de Rabelais : l'image du conteur et son rapport avec le texte

Ho-Youh Seuk. Les Métamorphoses d'Alcofribas dans l'œuvre de Rabelais : l'image du conteur et son rapport avec le texte . In: Bulletin de l'Association d'étude sur l'humanisme, la réforme et la renaissance, n°17, 1983. pp. 55-59

Les Métamorphoses d'Alcofribas dans l'œuvre de Rabelais : l'image du conteur et son rapport avec le texte

Ho-Youh Seuk. Les Métamorphoses d'Alcofribas dans l'œuvre de Rabelais : l'image du conteur et son rapport avec le texte . In: Bulletin de l'Association d'étude sur l'humanisme, la réforme et la renaissance, n°17, 1983. pp. 55-59