مهدی بخشی زاده

Membrane separation processes are interesting compared with the traditional processes such as distillation, extraction, absorption, etc. due to their superior advantages. Development and simulation of a precise mathematical model for description of phenomena occurred during permeation and transfer of components through membrane could enable one to improve their design, application and operation. In this research a two-dimensional model was used for simulation of CO2 and H2S removal from their mixture with CH4 (as a representative of natural gas sweetening) by absorption on MDEA aqueous solution in polypropylene hollow fiber membrane contactors. The model was solved and simulated using computational fluid dynamic (CFD) in COMSOL software by finite element method. Validation of the simulated CO2 fluxes (0.4 - 2.5 × 10-3 mol/m2.s) through the membrane vs. liquid phase velocity vs. experimental data reveled minimum, average, and maximum errors of 3.45, 9.56, and 17.45 % and those for the gas phase velocity were 2.64, 4.31, and 5.59 %, respectively. The results showed that the gas and liquid absorbent phases’ velocities are the most important affecting factors on the acid gas removal. Also, the liquid phase mass transfer resistance was found determining. With increase in membrane porosity, absorbent concentration and gas phase temperature, the gas outlet’s CO2 concentration were reduced by 45, 68, and 17.5 %, respectively. Increment in the gas and absorbent velocities, reduced and increased the CO2 absorption flux by 15 % and 4.5-fold, respectively. Simultaneous removal of H2S and CO2 reduces the only CO2 removal efficiency by~8 %.

Vitiligo is a chronic skin disease. Considering that this disease affects a person's appearance, psychological symptoms, such as depression, isolation, and low self-confidence, are very common in these patients. The present study aimed to determine the effectiveness of Acceptance and Commitment Therapy (ACT) on psychological symptoms of patients with vitiligo disease.

The present study employed a quasi-experimental design featuring a pre-test, post-test, and unequal control group. The statistical population of the research comprised soldiers and other military personnel with vitiligo who were serving in military centers of the armed forces in Tehran in 2020. The experimental group (n=11) received ACT, and the control group (n=13) did not receive any intervention. The subjects completed the questionnaires before and after the intervention. The analysis of covariance was used to analyze the data.

The results indicated that ACT improved depression, quality of life, and acceptance, and reduced experiential avoidance in vitiligo patients. No significant difference was observed in anxiety or mindfulness between the two groups. The effect size indicated that the differences between the groups were moderate.

ACT is an evidence-based treatment for vitiligo patients, and psychologists can use this treatment to improve the quality of life and reduce the psychological symptoms of these patients.

Urinary tract infections are one of the most commonly reported nosocomial infections caused by colonization of E. coli in the mucosal epithelium and in the formation of microbial biofilms, which damage the host tissue. The aim of this study was to determine the amount of biofilm formation of uropathogenic E. coli based on urinary tract stones of people with urinary tract infection.

In this study, 380 patients with positive urine culture with Escherichia coli bacteria were studied. Of these, 34 patients had urinary stone and urinary tract infection with E. coli at the same time. These rocks were sent to the laboratory in accordance with sterile conditions. To maintain and maintain a long-term bacteria to collect and perform other tests in such a way that the bacteria themselves are not harmed, they are stored in a glycerol stock state. To determine the biofilm formation capacity, this bacterium was investigated by Microtiter Plate method.

The results showed that a total of 34 stone samples were examined using conventional methods containing uropathogenic E. coli. These microorganisms showed a low biofilm strength of 18%, very low power, 20% moderate power and 59% high power.

In this study, the presence of infection with urinary stones as a suitable bed and surface for the uropathogenic E. coli and, as a result of biofilm formation of this bacterium on the surface of the stone, causes more urinary tract infection and also resistance an antibiotic in the strains that causes the urinary tract infection.