121 research outputs found
Dynamic Simulation, Parameter Optimization, and Control of a Reactive Distillation Column for Production of Isopropanol via Propylene Hydration
In this study, a reactive distillation column for production of isopropanol was investigated. Firstly, a dynamic model was developed for the process. The model of the process was then programmed, and the process simulated using a base case obtained from the literature. Results showed that distillate contained more than 58 mol% propylene-free isopropanol. In the next step, optimization of some operating variables was performed to maximize concentration of isopropanol in distillate with condenser temperature as constraint, which was considered to be above the freezing point of water. Several simulations were performed by changing operating parameters, and finally optimum isopropanol content in distillate was obtained above 58 mol%. Results of using classic controllers showed that PID controller had the best performance for both condenser temperature set-point tracking and disturbance rejection.
This work is licensed under a Creative Commons Attribution 4.0 International License
Caring burden and quality of life of family caregivers in patients undergoing hemodialysis: A descriptive-analytic study
Background: Caring role, especially in chronic diseases, has a negative impact on the health of family caregivers and can affect their quality of life.Therefore, this study aimed to investigate the care burden and quality of life in family caregivers of hemodialysis patients and their relationship with some characteristics of caregivers and patients.Methods: This study was conducted as a descriptive-analytic study in Isfahan from January to February 2017.Sampling was done using census.The number of participants was 254.The data gathering tools consisted of a three-part questionnaire including demographic characteristics, the Zarit questionnaire for caring burden, and SF-36 quality of life questionnaire.Data were analyzed using descriptive statistics, Pearson correlation coefficient test, Spearman�s coefficient, ANOVA, and univariate general linear regression.A significant level of 5 was considered.Results: The mean scores of the quality of life and caring burden were 30.4±9.9 and 44.8±6.2, respectively in caregivers.The age of the patient under care (P<0.01), cost of medications (P=0.08), and hours of care in 24 hours (P<0.01) had a significant relationship with care givers� quality of life.Also, univariate general linear regression revealed that care burden had a significant relationship with the quality of life (P=0.03).Conclusion: Family caregivers who experienced more caring burden had a low quality of life.The researchers suggest that supportive and educational programs should be designed and implemented for this group of patients and their caregivers. © 2019, Shriaz University of Medical Sciences. All rights reserved
Removal of Acid Brown 354 from wastewater by aminized cellulose acetate nanofibers: experimental and theoretical study of the effect of different parameters on adsorption efficiency
Wastewater effluents usually involve dyes that are dangerous for aquatic life and other environments. Many of these dyes are toxic, carcinogenic, and can cause skin and eye irritation. In this study, firstly aminized cellulose acetate was prepared from cellulose acetate and applied for the adsorption of Acid Brown 354 from aqueous solutions. The effects of different parameters including adsorbent dosage, pH, temperature, and initial concentration of dye on adsorption capacity were examined. Results showed that removal efficiency of dye declined by increasing values of all parameters. Finally, maximum removal of dye was achieved in the presence of 0.1 g adsorbent, pH of 2, and 10 mg/L of initial dye concentration at a temperature of 25 °C. Also, different adsorption isotherms were investigated including Langmuir, Temkin, and Freundlich models and results demonstrated that the adsorption isotherm of dye followed the Freundlich model with a correlation coefficient of 0.988 revealing that the bond between the dye and the adsorbent is strong. Finally, kinetic study indicated that the adsorption of dye is exactly governed by pseudo-second-order kinetics explaining that the adsorption process is chemical and the adsorbent can not be reused. © 2021 The Author
The effects of probiotics, prebiotics and synbiotics on the reduction of IBD complications, a periodic review during 2009–2020
Aims: To perform a systematic review on randomized controlled trials to examine the efficacy of probiotics, prebiotics and synbiotics in the treatment of IBD. Methods and Results: PubMed, Web of science, Scopus and Google Scholar were systematically searched from January 2009 to January 2020 using the following keywords: ‘Inflammatory Bowel Disease’, ‘Probiotics’ and ‘Clinical trial’. The statistical analysis was performed using SPSS software version 24.0. A total of 1832 articles were found during the initial search and 21 clinical trials were eligible. Studies comparing the effects of probiotics and placebo among patients with active ulcerative colitis (UC) showed a significant difference in clinical outcomes. Moreover, probiotics improved the overall induction of remission rates among patients with Crohn’s disease (CD). Probiotics significantly decreased the IL-1β, TNF-α and IL-8 levels. Also, the need for systemic steroids, hospitalization, surgery, as well as histological score and disease activity index significantly decreased in patients who used probiotic or pro-/synbiotics. Conclusions: The use of probiotics, as food supplements, can induce anti-inflammatory reactions, balance the intestinal homeostasis and induce remission in IBD. The efficacy of probiotics on remission induction is more reported in UC rather than CD. Larger well-designed clinical trials are needed to further determine whether probiotics are of clear benefits for remission in IBD. © 2020 The Society for Applied Microbiolog
Bovine Leukemia virus (BLV) and risk of breast cancer: A systematic review and meta-analysis of case-control studies
Background: Breast cancer is reported as one of the most common cancers among females worldwide. Infectious agents especially viruses have been considered as role players in the development of breast cancer. Although some investigations suggest an association between bovine leukemia virus (BLV) and breast cancer, the involvement of this virus as a risk factor remains controversial. The present study aimed to find out any possible association between BLV and breast cancer through conducting a systematic review and meta-analysis. Methods: Systematic literature search was performed by finding related case-control articles from the PubMed, Google Scholar, Web of Science, Scopus, and EMBASE databases. The heterogeneity and the multivariable-adjusted OR and corresponding 95 CI were applied by meta-analysis and forest plot across studies. All statistical analyses were performed using Stata 14.1. Result: Based on a comprehensive literature search, 9 case-control studies were included for meta-analysis. The combination of all included studies showed that BLV infection is associated with an increased risk of breast cancer summary OR (95% CI) 2.57 (1.45, 4.56). Conclusion: This is the first meta-analysis to analyze a potential association between BLV infection and the risk of breast cancer. Control of the infection in cattle herds and screening of the milk and dairy products may help to reduce the transmission of the virus to humans. © 2020 The Author(s)
The effects of probiotics, prebiotics and synbiotics on the reduction of IBD complications, a periodic review during 2009�2020
Aims: To perform a systematic review on randomized controlled trials to examine the efficacy of probiotics, prebiotics and synbiotics in the treatment of IBD. Methods and Results: PubMed, Web of science, Scopus and Google Scholar were systematically searched from January 2009 to January 2020 using the following keywords: �Inflammatory Bowel Disease�, �Probiotics� and �Clinical trial�. The statistical analysis was performed using SPSS software version 24.0. A total of 1832 articles were found during the initial search and 21 clinical trials were eligible. Studies comparing the effects of probiotics and placebo among patients with active ulcerative colitis (UC) showed a significant difference in clinical outcomes. Moreover, probiotics improved the overall induction of remission rates among patients with Crohn�s disease (CD). Probiotics significantly decreased the IL-1β, TNF-α and IL-8 levels. Also, the need for systemic steroids, hospitalization, surgery, as well as histological score and disease activity index significantly decreased in patients who used probiotic or pro-/synbiotics. Conclusions: The use of probiotics, as food supplements, can induce anti-inflammatory reactions, balance the intestinal homeostasis and induce remission in IBD. The efficacy of probiotics on remission induction is more reported in UC rather than CD. Larger well-designed clinical trials are needed to further determine whether probiotics are of clear benefits for remission in IBD. © 2020 The Society for Applied Microbiolog
Comparison of confirmed COVID-19 with SARS and MERS cases - Clinical characteristics, laboratory findings, radiographic signs and outcomes: A systematic review and meta-analysis
Introduction: Within this large-scale study, we compared clinical symptoms, laboratory findings, radiographic signs, and outcomes of COVID-19, SARS, and MERS to find unique features. Method: We searched all relevant literature published up to February 28, 2020. Depending on the heterogeneity test, we used either random or fixed-effect models to analyze the appropriateness of the pooled results. Study has been registered in the PROSPERO database (ID 176106). Result: Overall 114 articles included in this study; 52 251 COVID-19 confirmed patients (20 studies), 10 037 SARS (51 studies), and 8139 MERS patients (43 studies) were included. The most common symptom was fever; COVID-19 (85.6, P <.001), SARS (96, P <.001), and MERS (74, P <.001), respectively. Analysis showed that 84 of Covid-19 patients, 86 of SARS patients, and 74.7 of MERS patients had an abnormal chest X-ray. The mortality rate in COVID-19 (5.6, P <.001) was lower than SARS (13, P <.001) and MERS (35, P <.001) between all confirmed patients. Conclusions: At the time of submission, the mortality rate in COVID-19 confirmed cases is lower than in SARS- and MERS-infected patients. Clinical outcomes and findings would be biased by reporting only confirmed cases, and this should be considered when interpreting the data. © 2020 John Wiley & Sons, Lt
Measuring cardiomyocyte cellular characteristics in cardiac hypertrophy using diffusion‐weighted MRI
Purpose:
This paper presents a hierarchical modeling approach for estimating cardiomyocyte major and minor diameters and intracellular volume fraction (ICV) using diffusion-weighted MRI (DWI) data in ex vivo mouse hearts.
Methods:
DWI data were acquired on two healthy controls and two hearts 3 weeks post transverse aortic constriction (TAC) using a bespoke diffusion scheme with multiple diffusion times (
), q-shells and diffusion encoding directions. Firstly, a bi-exponential tensor model was fitted separately at each diffusion time to disentangle the dependence on diffusion times from diffusion weightings, that is, b-values. The slow-diffusing component was attributed to the restricted diffusion inside cardiomyocytes. ICV was then extrapolated at
using linear regression. Secondly, given the secondary and the tertiary diffusion eigenvalue measurements for the slow-diffusing component obtained at different diffusion times, major and minor diameters were estimated assuming a cylinder model with an elliptical cross-section (ECS). High-resolution three-dimensional synchrotron X-ray imaging (SRI) data from the same specimen was utilized to evaluate the biophysical parameters.
Results:
Estimated parameters using DWI data were (control 1/control 2 vs. TAC 1/TAC 2): major diameter—17.4
m/18.0
m versus 19.2
m/19.0
m; minor diameter—10.2
m/9.4
m versus 12.8
m/13.4
m; and ICV—62%/62% versus 68%/47%. These findings were consistent with SRI measurements.
Conclusion:
The proposed method allowed for accurate estimation of biophysical parameters suggesting cardiomyocyte diameters as sensitive biomarkers of hypertrophy in the heart
Measuring cardiomyocyte cellular characteristics in cardiac hypertrophy using diffusion‐weighted MRI
Purpose: This paper presents a hierarchical modeling approach for estimating cardiomyocyte major and minor diameters and intracellular volume fraction (ICV) using diffusion‐weighted MRI (DWI) data in ex vivo mouse hearts. Methods: DWI data were acquired on two healthy controls and two hearts 3 weeks post transverse aortic constriction (TAC) using a bespoke diffusion scheme with multiple diffusion times ( Δ ), q‐shells and diffusion encoding directions. Firstly, a bi‐exponential tensor model was fitted separately at each diffusion time to disentangle the dependence on diffusion times from diffusion weightings, that is, b‐values. The slow‐diffusing component was attributed to the restricted diffusion inside cardiomyocytes. ICV was then extrapolated at Δ = 0 using linear regression. Secondly, given the secondary and the tertiary diffusion eigenvalue measurements for the slow‐diffusing component obtained at different diffusion times, major and minor diameters were estimated assuming a cylinder model with an elliptical cross‐section (ECS). High‐resolution three‐dimensional synchrotron X‐ray imaging (SRI) data from the same specimen was utilized to evaluate the biophysical parameters. Results: Estimated parameters using DWI data were (control 1/control 2 vs. TAC 1/TAC 2): major diameter—17.4 μ m/18.0 μ m versus 19.2 μ m/19.0 μ m; minor diameter—10.2 μ m/9.4 μ m versus 12.8 μ m/13.4 μ m; and ICV—62%/62% versus 68%/47%. These findings were consistent with SRI measurements. Conclusion: The proposed method allowed for accurate estimation of biophysical parameters suggesting cardiomyocyte diameters as sensitive biomarkers of hypertrophy in the heart
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