Oxygen-Free Propane Oxidative Dehydrogenation Over Vanadium Oxide Catalysts: Reactivity and Kinetic Modelling

Propane conversion to propylene has been the subject of intensive researches. This is due to the increasing demand for propylene. Current propylene production processes suffer from several limitations. Oxidative dehydrogenation (ODH) is a promising alternative technology for propylene production overcoming the drawbacks of current processes. However, selectivity control in ODH is still a challenge preventing it from an industrial application. This is due to the formation of undesired carbon oxides. Thus, the development of a selective catalyst is crucial for the commercialization of ODH. Vanadium oxide catalysts have been proposed as the most active and selective catalyst for propane ODH. Moreover, new reactor concepts such as fluidized-bed might also help to make the ODH a feasible alternative for olefins productionas, offering some outstanding advantages in comparison to conventional reactors. This dissertation provides fundamental understanding of structure-reactivity relationship of vanadium oxide catalyst for propane ODH in a fluidized-bed reactor using the lattice oxygen of vanadium oxide catalysts in the absence of gas-phase oxygen. Supported vanadium oxide catalysts with different vanadium loadings (5-10 wt %) supported on γ-Al2O3 is used. The prepared catalysts are characterized using several techniques such as BET surface area, H2-TPR, NH3-TPD, O2 Chemisorption, Laser Raman Spectroscopy, Pyridine FTIR and XRD. Characterization of the catalysts reveals that monomeric VOx species are predominant at low vanadium loadings while polymeric VOx species increase with higher loadings until monolayer surface coverage is reached. Moreover, the catalysts display moderated acidity compared to that of the bare alumina due to the relative increase in the number of Brønsted acid sites. Successive-injections propane ODH experiments in the CREC Riser Simulator over partially reduced catalyst show good propane conversions (12%-15%) and promising propylene selectivity (68-86%) at 475-550 0C. Product selectivities are found to augment with the catalyst’s degree of reduction suggesting that a certain degree of catalyst reduction is required for better propylene selectivity. Compared to average propylene yields of 5% and 15% obtained in FCC and steam cracking technologies, respectively, promising value of 7% was obtained in the present propane ODH study over vanadium oxide catalyst and under oxygen free conditions. Such result would encourage further investigation of propane ODH in the absence of molecular gas oxygen as promising alternative/supplementary technology for the production of propylene. A kinetic model relating reaction rate to the catalyst’s degree of oxidation is proposed. Non- linear regression leads to model parameters with low confidence intervals, suggesting the adequacy of the proposed model in predicting the ODH reaction under the selected reaction conditions

Prevalence of overweight and obesity based on the body mass index; a cross-sectional study in Alkharj, Saudi Arabia

Background: Obesity and overweight are accompanied with several different chronic diseases. Overweight and obesity can be measured by using body mass index (BMI) and is also used widely as an index of relative adiposity among any population. The aim of the study is to evaluate the prevalence of overweight and obesity among general population in Al-Kharj, Saudi Arabia.Methods: Cross-sectional analysis was undertaken from a representative sample (N = 1019) of the Al Kharj population. Anthropometric measurements including the waist circumference (in centimeters), height (in meters), and weight (in kilograms) of the subjects were undertaken by means of standard apparatus. SPSS 24.0 was utilized for statistical analysis of the data.Results: Majority of respondents in this study were overweight and obese (54.3%) compared with 45.7% being non-obese. A linear positive association of increasing BMI with older age groups was present in males and females. Men had larger waist circumference, weight and height measures as compared with their female counterparts. Regression analysis showed increasing age, being married and high serum cholesterol to be the significant predictors of overweight and obesity while gender, education level, job status, and having diabetes were not.Conclusions: The obesity-overweight prevalence in the Saudi population is high mainly across both genders. However, the associated factors are potentially preventable and modifiable. The regional barriers to lifestyle modifications and interventions to encourage active lifestyles, especially among adolescents to limit the occurrence of obesity and ultimately promote health and wellbeing, are warranted. Furthermore, prospective studies are needed in future to confirm the aetiological nature of such associations

Prevalence and correlates of diastolic dysfunction in patients with hypertension: a cross-sectional study from in The Kingdom of Saudi Arabia

Introduction: diastolic dysfunction refers to impaired ventricular relaxation or filling regardless of ejection fraction and symptoms. It accounts for 8% and 25% in the hospitalized and general population, respectively. The present study was conducted to determine the prevalence and correlates of diastolic dysfunction in hypertensive patients living in Saudi Arabia. Methods: a multicentric, cross-sectional study was conducted from February 2019 to February 2020 at King Khalid Hospital and Prince Sultan Center for Health Services, Prince Sattam Bin Abdulaziz University hospital in Al Kharj, and Al Kharj Military Industries Corporation hospital, KSA. All patients with hypertension who underwent an echocardiography were included in the study. Logistic regression analysis was performed to determine factors associated with left ventricular diastolic dysfunction (LVDD). Results: the study included a total of 104 participants, where 51.9% were females andthe mean age of the patients was 48.01±12.81 years.Most patients had an abnormal echocardiography finding (64.4%, n = 67). The most common abnormalities were left ventricular (LV) hypertrophy (44.2%, n = 46), and diastolic dysfunction, (35.6%, n = 37). The study revealed that age (aOR: 6.1, 95% CI 1.17-31.3; p = 0.032) and dyslipidemia (aOR: 3.45, 95% CI 1.16-10.24; p = 0.026) have significant association with LVDD in the patients with hypertension. Conclusion: in conclusion, diastolic dysfunction is prevalent among older hypertensive patients and those with dyslipidaemia. Age and dyslipidaemia were non-modifiable and modifiable factors associated with LVDD in hypertensive patients, respectively

Prevalence of prediabetes, diabetes and Its predictors among females in alkharj, saudi arabia: A cross-sectional study.

BACKGROUND/OBJECTIVE: The prevalence of prediabetes and diabetes is reaching epidemic proportions across the globe. Therefore, this study aims to determine the prevalence of prediabetes and diabetes, together with its accompanying risk factors, among young females. METHODS: An exploratory cross-sectional survey was conducted with 638 Saudi females in Alkharj, Saudi Arabia. Statistical analysis was carried out using STATA version 14. Odds ratios for the risk of diabetes and associated factors were calculated using log-binomial and multinomial logistic regression. Standardized prevalence and strata-specific prevalence of diabetes and prediabetes for different risk factors were also calculated. FINDINGS: The study revealed that nondiabetics and prediabetics were more prevalent between the ages of 18 and 24 years, while diabetic patients were consistently between 25 to 44 years of age. The average value for HbA1c in females was 5.44. Regression analysis shows that being older, married, obese, a smoker or less educated significantly increases the risk for both prediabetes and diabetes. Mutivariable analysis revealed obesity had a significant association with both prediabetes and diabetes. Prediabetics were 2.35 times more likely to be obese as compared to nondiabetics, with 95% CI (1.38-3.99). Similarly, diabetics were 6.67 times more likely to be obese compared to nondiabetics 95% CI (1.68-26.42). CONCLUSION: Our study shows the prevalence of diabetes and prediabetes among females from Al Kharj was 3.8% and 18.8%, respectively. The diabetic and prediabetic female participants had higher mean BMI and waist circumference, were older in age, were married, and smoked as compared to nondiabetics. In the context of the findings of our study, and keeping in view the the burden of this disease globally and in our population, it has now become extremely important to understand these factors and encourage health-promoting behaviors to construct effective interventions

Prevalence of prediabetes, diabetes, and Its associated risk factors among males in Saudi Arabia: A population-based survey

Objectives: The study aims at determining the prevalence of prediabetes and diabetes and at ascertaining some concomitant risk factorsamong males in Saudi Arabia.Methods: A population-based cross-sectional study including 381 Saudi adult males from different institutions was recruited. Odds ratios for diabetes risk and risk factors were calculated using log-binomial and multinomial logistic regression, using STATA version 12.Results: The participants included 381 diabetic males with a median age of 45 years, average body mass index of 25 ± 40 kg/m2, whereas waist circumferences ranged from 66 to 180 cm in the male study population. In addition, 27.82% had normal BMI, 32.28% were overweight, and 36.22% were obese. Around 36% had higher waist circumference, that is, \u3e102 cm. Age, BMI, marital status, and educational attainment were statistically significant predictors for prediabetes and diabetes.Conclusion: This study found that the prevalence of diabetes and prediabetes was 9.2% and 27.6%, respectively, for male Al-Kharj study population. The factors that increase the risk of diabetes and prediabetes include older age, obesity and overweight, being married, smoker, and having a civilian job and less education. All these factors were found statistically significant except smoking status and job type. In order to evaluate the causal relationship of these factors, prospective studies are required in future

Ameliorative inhibition of sirtuin 6 by imidazole derivative triggers oxidative stress-mediated apoptosis associated with Nrf2/Keap1 signaling in non-small cell lung cancer cell lines

Background: Redox homeostasis is the vital regulatory system with respect to antioxidative response and detoxification. The imbalance of redox homeostasis causes oxidative stress. Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2, also called Nfe2l2)/Kelchlike ECH-associated protein 1 (Keap1) signaling is the major regulator of redox homeostasis. Nrf2/Keap1 signaling is reported to be involved in cancer cell growth and survival. A high level of Nrf2 in cancers is associated with poor prognosis, resistance to therapeutics, and rapid proliferation, framing Nrf2 as an interesting target in cancer biology. Sirtuins (SIRT1-7) are class III histone deacetylases with NAD + dependent deacetylase activity that have a remarkable impact on antioxidant and redox signaling (ARS) linked with Nrf2 deacetylation thereby increasing its transcription by epigenetic modifications which has been identified as a crucial event in cancer progression under the influence of oxidative stress in various transformed cells. SIRT6 plays an important role in the cytoprotective effect of multiple diseases, including cancer. This study aimed to inhibit SIRT6 using an imidazole derivative, Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate, to assess its impact on Nrf2/Keap1 signaling in A549 and NCI-H460 cell lines.Method: Half maximal inhibitory concentration (IC50) of Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate was fixed by cell viability assay. The changes in the gene expression of important regulators involved in this study were examined using quantitative real-time PCR (qRT-PCR) and protein expression changes were confirmed by Western blotting. The changes in the antioxidant molecules are determined by biochemical assays. Further, morphological studies were performed to observe the generation of reactive oxygen species, mitochondrial damage, and apoptosis.Results: We inhibited SIRT6 using Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate and demonstrated that SIRT6 inhibition impacts the modulation of antioxidant and redox signaling. The level of antioxidant enzymes and percentage of reactive oxygen species scavenging activity were depleted. The morphological studies showed ROS generation, mitochondrial damage, nuclear damage, and apoptosis. The molecular examination of apoptotic factors confirmed apoptotic cell death. Further, molecular studies confirmed the changes in Nrf2 and Keap1 expression during SIRT6 inhibition.Conclusion: The overall study suggests that SIRT6 inhibition by imidazole derivative disrupts Nrf2/Keap1 signaling leading to oxidative stress and apoptosis induction

The association between olive oil consumption and primary prevention of cardiovascular diseases

Introduction: American Heart Association and many other recommend Mediterranean diet for patients with cardiovascular risk. This systematic review and meta-analysis are conducted to review the effects of Mediterranean diet on the cardiovascular events as reported in randomized controlled trials (RCTs). Methods: A systematic research is conducted on MEDLINE via Ovid, Embase, PubMed, Google Scholar, Web of Science, and Informit. Databases of studies conducted between 2000 and 2017 were included in the analysis. All the collected studies were screened, and at the end, seven RCTs met the inclusion criteria. All the characteristics of trails such as study design, interventions, follow-up duration, and primary and secondary outcomes were recorded. RevMan was used to evaluate risk reduction in each trial individual using forest plot and fixed effects. Results: Four studies were included in the review, having a total of 25,195 participants. The effects of Mediterranean diet were found in cardiovascular events (627), coronary events (251), and all-cause death (887). The analysis revealed that there is a statistically significant relationship between Mediterranean diet and reduction in cardiovascular events at P = 0.02. However, other parameters did not show any statistically significant results that need further investigation. Conclusion: The individual RCT provides evidence of protective effects of the Mediterranean diet on cardiovascular events. However, the quality and quantity of data available in those trails are not reliable and limited. Therefore, the results of those trails must be cautiously interpreted

Popularity and impact of using smart devices in medicine: experiences in Saudi Arabia

Abstract Background The present study aimed to investigate smart device medical apps currently preferred by physicians in Saudi Arabia and the perceived impact of the apps on patient care. Methods Questionnaires for this cross-sectional study on smart device medical apps were randomly emailed to 384 physicians registered in the Saudi Commission of Health Specialists database. A total of 300 physicians returned completed questionnaires, with a response rate of 78.5%. Physician demographics and their perceptions of medical apps were assessed, including questions on the purpose, impact, and types of medical apps used. Questions were answered using a Likert scale (1 = strongly disagree, 2 = disagree, 3 = not sure, 4 = agree, and 5 = strongly agree). Results Study subjects had a median age of 39 years (57.7% male). Most respondents (88.3%) had smart devices, and 86.3% had at least one medical app installed. Just over half used an app at least once a day (53.0%). Medical apps were positively perceived, with physicians reporting increased dependency on the apps (Likert score: 4.7 ± 0.5). Conclusion Medical apps were perceived to positively impact education, physician efficiency, and patient care

Update on Middle East respiratory syndrome coronavirus epidemiology, diagnosis and management

In the mid of 2012, Middle East respiratory syndrome otherwise termed as, coronavirus (MERS-CoV) emerged among the leading serious infection within the peninsula region with chances of transmission to the most parts of the world. The greatest infection was first confirmed in the Northern part of Saudi Arabia where 50 deaths were experienced and 80 ceases of illness were reported. Apart from the reported cases, possible laboratory reports confirmed that such a compulsory sequence of infection is mainly transmitted through Carmel and bats. While there is no specific cure for coronavirus (MERS-CoV), International health governing authorities such as world health organization and the Pan American Health organization (PAHO) have placed recommendations to healthcare institutions of different countries to provide relevant information with regard to preventive measures of the disease.Such has been brought amid skepticism that the disease has no cure. Therefore, regulating prevalence rate of MERS-CoV through means such; as environmental engineering controls, administrative measures and immediate isolation of the infected patients, plays best to curb the rate of infection

The association between watching television and obesity in children of school-age in Saudi Arabia

Background: There is little information on the association between watching Television (TV) and obesity in the Arabian Peninsula. Aim of the Study: The aim of this study was to explore the association between the watching of television and obesity in Saudi children of school-age. Materials and Methods: A case-controlled study was conducted with students between the ages of 9 and 14 years who attended the school health clinic in King Abdulaziz Housing for National Guard (Iskan), Riyadh, Saudi Arabia, during the study period (February to April 2012). During each clinic, children were selected by simple random sampling (five obese and five non-obese). For data collection, two trained physicians interviewed the participants using a 20-item Arabic questionnaire. Well-trained nurses collected the anthropometric measurements of weight and height. Results: The study included 397 students. Higher (body mass index) BMI was associated with a higher number of televisions at home (P < 0.001), watching TV for more than three hours per day at the weekend (P = 0.047), eating more than three snacks per day (P = 0.005), watching TV at night (P = 0.026), and siblings′ decisions on how much TV to watch (P = 0.025). The prevalence of childhood obesity was significantly lower among those whose mothers determined how much TV they could watch (P = 0.03). In logistic regression analysis, the increase in the child′s age, the presence of more than one TV at home, having his or her own TV, and an increase in the number of hours of watching TV over the weekend were significantly associated with an increased risk of childhood obesity. Personal computers and the Internet were not significantly associated with an increased risk of childhood obesity. Conclusion: The present investigation revealed that watching TV represents an important risk factor for obesity in children of school-age