Modelling and Fuzzy-Decision-Making of Batch Cultivation of Saccharomyces cerevisiae using Different Mixing Systems

This study is focussed on the modelling and fuzzy-decision-making of impulse mixing and vibromixing for a Saccharomyces cerevisiae batch cultivation. Different substrate inhibition models (Monod, Aiba, Andrews, Haldane, Luong, Edward, and Han-Levenspiel) have been considered in order to explain the cell growth kinetics. The results obtained (correlation coefficient, Fisher coefficient, relative error and statistics l) show that all growth rate models are adequate and can be used for modelling. The investigations have shown that the most suitable for both mixing systems (according to the best statistical indicators) is the Luong growth rate model, which will be used for the process modelling. A fuzzy-decision-making procedure is developed with the initial conditions (maximal rotation speed for the impulse mixing and maximal amplitude for the vibromixing systems). The developed optimisation and results obtained have shown that the impulse mixing systems have better productiveness and better glucose assimilation. In addition, it is easier to realize this system

INFLUENCE OF COLCHICINE ON THROMBOCYTOPOIESIS AND PLASMA THROMBOCYTOPOIЕТIN ACTIVITY IN RATS

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A Combined Algorithm for Multi-objective Fuzzy Optimization of Whey Fermentation

In this paper, multi-objective fuzzy optimization is applied to finding an optimal policy of a fed-batch fermentation process for lactose oxidation from a natural substratum by a strain Kluyveromyces marxianus var. lactis MC 5. The optimal policy consisted of feed flow rate, feed concentration of the substrate and initial concentration of the substrate. The multi-objective problem corresponds to the process productiveness, and the cost of the substrate. A simple combined algorithm guidelines the finding of a satisfactory solution to the general multi-objective optimization problem. The combined algorithm includes a method for random search for finding an initial point and a method based on fuzzy sets theory, combined in order to find the best solution of the optimization problem. The obtained optimal control results have shown an increase of process productiveness and a decrease of the remaining objective functions

Pharmacological inhibition of Bcl-xL sensitizes osteosarcoma to doxorubicin

High-grade conventional osteosarcoma is the most common primary bone tumor. Prognosis for osteosarcoma patients is poor and resistance to chemotherapy is common. We performed an siRNA screen targeting members of the Bcl-2 family in human osteosarcoma cell lines to identify critical regulators of osteosarcoma cell survival. Silencing the anti-apoptotic family member Bcl-xL but also the pro-apoptotic member Bak using a SMARTpool of siRNAs as well as 4/4 individual siRNAs caused loss of viability. Loss of Bak impaired cell cycle progression and triggered autophagy. Instead, silencing Bcl-xL induced apoptotic cell death. Bcl-xL was expressed in clinical osteosarcoma samples but mRNA or protein levels did not significantly correlate with therapy response or survival. Nevertheless, pharmacological inhibition of a range of Bcl-2 family members showed that inhibitors targeting Bcl-xL synergistically enhanced the response to the chemotherapeutic agent, doxorubicin. Indeed, in osteosarcoma cells strongly expressing Bcl-xL, the Bcl-xL-selective BH3 mimetic, WEHI-539 potently enhanced apoptosis in the presence of low doses of doxorubicin. Our results identify Bcl-xL as a candidate drug target for sensitization to chemotherapy in patients with osteosarcoma

Fuzzy-Decision-Making Problem of L-Lysine Production

A fuzzy-decision-making procedure is applied to find the optimal feed policy of a fed-batch fermentation process for L-lysine production in a stirred tank bioreactor from Brevibacterium flavum 22LD. The policy consists of a feed flow rate, feed concentration of glucose and threonine, and fermentation time. In this paper the fermentation process is formulated as a general multiple objective optimization problem. By using an assigned membership function for each of the objectives, the general multiple objective optimization problem can be converted into a maximizing decision problem. In order to obtain a global solution, a method of fuzzy sets theory is introduced to solve the maximizing decision problem. This method allows direct determination of the optimization problem solution. The applied multiple objective optimization of the process has shown a vast increase of its productivity and decrease of the glucose and threonine concentration at the end of the process

Higher blood pressure in normoalbuminuric type 1 diabetic patients with a familial history of type 2 diabetes

Background: To adress whether type 1 diabetic patients with type 2 diabetic first degree relatives are different from others in terms of cardiovascular risk factors, insulin resistance and daily insulin dosage

Effect of oxidative stress on glutathione pathway in red blood cells from patients with insulin-dependent diabetes mellitus

Recently, increased oxidative stress and impaired antioxidant defense have been suggested as a contributory factor for initiation and progression of complications in diabetes. Although glutathione (GSH) and the enzymes included by glutathione redox cycle have an important role for protection of cells against free radical-mediated damage, they may be susceptible to oxidation themselves. We examined the susceptibility of the GSH pathway to oxidation and inactivation in subjects with well-controlled and poorly controlled insulin-dependent diabetes mellitus (IDDM) versus controls and the effect of glycemic control on this susceptibility. Red blood cells (RBCs) were isolated, RBC level of GSH, activity of glutathione peroxidase (G-Px), and glutathione reductase (G-Red) were measured at the baseline and after a 2-hour incubation with hydrogen peroxide. Significant decreases were observed in the GSH level and in the activity of GSH peroxidase and GSH reductase in all the groups after the incubation with hydrogen peroxide. Maximum decrease was observed in the poorly controlled diabetic group for all parameters. This result indicates that the GSH pathway is susceptible to oxidation; and this susceptibility increases in poorly controlled diabetics. Therefore, insufficient antioxidant defense by the GSH pathway may be one of the factors responsible for development of complications in patients with IDDM. Copyright 2002, Elsevier Science (USA). All rights reserved

Susceptibility of glutatione and glutathione-related antioxidant activity to hydrogen peroxide in patients with type 2 diabetes: effect of glycemic control

Objectives: The aim of the present study was to examine the susceptibility of glutathione (GSH) and glutathione related antioxidant enzymes to oxidation in type 2 diabetic patients with and without glycemic control

O-6-methylguanine DNA methyltransferase activity in diabetic patients

In the present study, we evaluated O-6-methylguanine-DNA methyltransferase (MGMT) activity in diabetic patients. The study was performed on 27 patients with Type 1 diabetes, and 42 with Type 2 diabetes. Patients with complications were excluded from the study. 36 non-diabetic volunteers, non-smokers who do not consume alcoholic beverage, were chosen from the medical staff as control subjects. MGMT activity was measured by the transfer of radiolabeled methyl groups from a prepared methylguanine-DNA substrate to the enzyme fraction of leukocyte extract. Leukocyte MGMT activity was significantly reduced in both Type 1 and Type 2 diabetes patients as compared with control subjects (P < 0.001). The present study demonstrates decreased MGMT activity in leukocytes from patients with Type 1 and Type 2 diabetes. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved