Dynamic analysis and buckling of variable thickness laminated composite beams using conventional and advanced finite element formulations

The behavior of variable thickness laminated composite beams has not so far been fully understood. In the present thesis, a finite element formulation is established for uniform and variable thickness composite beams (externally and mid-plane tapered composite beams). First the conventional formulation is used to establish the stiffness, geometric stiffness (for constant axial load, uniformly distributed axial load, and non-uniformly distributed axial load), and mass matrices. Second a new formulation (advanced formulation) is established, which considers not only the geometric boundary conditions, but also the natural boundary conditions. This means that at each node there will be four degrees of freedom, that are deflection, slope, bending moment, and shear force, such that all physical parameters that can be encountered in any practical situation can be included in the element formulation. The new stiffness, geometric stiffness, and mass matrices corresponding to the new formulation are set up. These matrices are provided into the MATLAB ® environment to obtain the natural frequencies and the critical buckling load

Biochemical effects of Resveratrol and Curcumin combination on obese diabetic rats

Abstract Obesity is a global health problem associated with various metabolic disorders as type-2 diabetes, cardiovascular diseases, and oxidative stress. Therefore, utilization of nontoxic natural products represents a logical preventive and/or therapeutic approach for it. The aim of the present article is to evaluate anti-obesity and antioxidant effects of curcumin (50 mg/kg.b.w) and resveratrol (25 mg/kg.b.w) and their combinatorial formulation in obese diabetic rats feed high fat diet (HFD) for 8 consecutive weeks prior. The results of this study also showed that curcumin and resveratrol, both individually and in combination showed antioxidant and anti-obesity actions in experimental diabetic rats for 8 consecutive weeks prior. Indeed, them combination was significantly prevented the increase in the levels of body weight gain, blood glucose, triacylglycerols, total cholesterol, LDL-C, HDL-C, free fatty acids, atherogenic index, thiobarbituric acid reactive substances (TBARS) in the liver tissue and improved the insulin resistance index, reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD) when compared to the high fat diet (HFD) control than either agent alone. The results clearly suggest that the combination of dietary curcumin and resveratrol produced a higher anti-obesity, anti-atherogenic, anti-diabetic and antioxidant activities on experimental obese diabetic rats than their individual influences

Workplace Psychosocial Factors and Mental Health among a Sample of Expatriates and the Country’s Nationals Who Working at King Khalid University, Saudi Arabia

Worplace stress is the harmful physical and emotional response that occurs when there is a poor match between job demands and the capabilities, resources, or needs of the worker. Mental health is an important issue in the workplace, particularly in developing countries. This study was aimed to explore the workplace psychosocial factors and mental health among expatriates and the country’s nationals; examine the relationship between workplace psychosocial factors and mental health. . The sample was composed of 518 country's nationals and 554 expatriates teaching staff on job at King Khalid University. Two tools were used for data collection: Socio-demographic data sheet, and Copenhagen Psychosocial Questionnaire (COPSOQ). The study results indicated that Poor mental health had a strongly statistically significant positive correlation with “quantitative  demands”,” Work-family conflict”, and “Emotional demands “ in total country’s nationals and expatriates   (p<0.01). While it was a strongly statistically significant negative  correlation with “Work pace”, “Influence at work”, “Social support from colleague”, “Social support from supervisors”, “Meaning of work”, “Commitment to the workplace” “Predictability”, and  “Recognition” (p<0.01). It was concluded that country's nationals experience worse mental health than expatriates and  this  to some extent caused by exposure to psychosocial factors at work. It has indicated the importance of taking action to reduce psychosocial factors, as this would benefit both country’s nationals and expatriate workers. Key words: Expatriates , country's nationals , workplace psychosocial factors, mental health

STUDY OF THE ANTI-HYPERLIPIDEMIC EFFECT OF THE COMBINED ADMINISTRATION OF THREE NATURAL EXTRACTS IN A POLOXAMER-407 HYPERLIPIDEMIC MODEL AND THEIR LC-ESI-MS/MS2 AND HPLC PROFILING

Objective: Dyslipidaemia is considered a high-risk factor for inducing atherosclerosis and cardiovascular diseases (CVDs). This study aims to investigate the anti-hyperlipidemic effect of the co-administration of the ethanol extracts of both ginger (root and rhizome) and leek (leaves and bulbs) in addition to the aqueous extract of gum arabic.  Methods: Rats were divided into eight groups: Hyperlipidaemia was induced in rats by a single intraperitoneal injection of Poloxamer 407 (P-407) [1 g/kg], negative control [saline injected], hyperlipidemic control [P-407 injected], positive control [Atorvastatin 70 mg/kg], groups four, five and six received ginger extract (400 mg/kg), leek extract (500 mg/kg) and gum arabic aqueous extract (7.5 g/kg) respectively and groups seven and eight received a co-administration of ginger, leek and gum arabic extracts at doses A and B respectively. Lipid profile was monitored. The profiling of all the tested extracts was performed by LC-ESI/MS and HPLC. Results: A significant anti-hyperlipidemic activity (P<0.05) was seen for group eight among all the tested groups producing ≈54%, 72%, 50% and 72% decrease in the measured parameters total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) respectively. An overall of 56 and 45 compounds were tentatively identified in the ethanol extracts of ginger and leek, respectively. Galactose and arabinose sugars were found to be the major saccharides in gum arabic and glucuronic acid was the major polyuronide part. Conclusion: the co-administration of a group of natural extracts in the given concentration proved to be more effective than the use of synthetic drugs or the use of a single component.&nbsp

EFFECT OF RUMINAL BACTERIA (ZAD) ON CHEMICAL COMPOSITION OF ROUGHAGES

Four common Egyptian Agricultural by products used for ruminant feeding were treated with different concentrations of Probiotic (ZAD) to study the effect of treatment on chemical composition of roughages. Roughages used were rice straw (RS), wheat straw (WS), corn stover (CS) and sugar cane bagasse (SCB). Concentrations of ZAD tested in this study were 0.05, 1.0, 1.5 and 2 ml/Kg of roughage. Roughages were mixed with ZAD solution and incubated anaerobically for 4 weeks. Results indicated that treatments decreased crude fiber (CF) contents of all roughages by 17 % in CS to 30% in SCB and increased EE by multiplication of 1.45 times in WS to 4.9 times in SCB. Statistical analysis showed no significant interaction between roughage source and ZAD concentration on chemical composition of roughages except for crude protein where interaction was significant (P<.05). Results also indicated that ZAD concentration over 0 ml/kg affected CF & CP contents, it was also noticed that CP of RS showed the highest response for treatment followed by SCB and CS, respectively. Crude protein of WS was not affected by different ZAD concentration. It was concluded that ZAD concentration of 1 ml/ 1 Kg of roughage is recommended for treatment to improve roughage chemical analysis

Recent Development in Antioxidant of Milk and Its Products

Free radicals are produced in humans through natural metabolism or the external environment, such as diet. These free radicals are neutralized by the antioxidant system, whereas enzymes, for example, catalase, superoxide dismutase, and glutathione peroxidase, play an important role in preventing excessive free radicals. Food antioxidants give a good hand in enhancing the human antioxidant system; high consumption of a diet rich in natural antioxidants protects against the risk of diseases such as cardiovascular, cancer, diabetes, and obesity. Milk and its products are popular for a wide range of consumers. Milk contains casein, whey protein, lactoferrin, milk lipid and phospholipids, vitamins, and microelements, for example, selenium (Se), which have antioxidant properties. Furthermore, probiotication of milk either sweet or fermented could enhance the antioxidant capacity of milk. This chapter focuses on presenting recent review data on milk components with antioxidant activity and their health benefits, probiotics as antioxidant agents, and methods for enhancing the antioxidant capacity of dairy products. The key aim of this chapter is to focus on major strategies for enhancing the antioxidant capacity of milk and its products

BJS commission on surgery and perioperative care post-COVID-19

Background: Coronavirus disease 2019 (COVID-19) was declared a pandemic by the WHO on 11 March 2020 and global surgical practice was compromised. This Commission aimed to document and reflect on the changes seen in the surgical environment during the pandemic, by reviewing colleagues' experiences and published evidence. Methods: In late 2020, BJS contacted colleagues across the global surgical community and asked them to describe how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had affected their practice. In addition to this, the Commission undertook a literature review on the impact of COVID-19 on surgery and perioperative care. A thematic analysis was performed to identify the issues most frequently encountered by the correspondents, as well as the solutions and ideas suggested to address them. Results: BJS received communications for this Commission from leading clinicians and academics across a variety of surgical specialties in every inhabited continent. The responses from all over the world provided insights into multiple facets of surgical practice from a governmental level to individual clinical practice and training. Conclusion: The COVID-19 pandemic has uncovered a variety of problems in healthcare systems, including negative impacts on surgical practice. Global surgical multidisciplinary teams are working collaboratively to address research questions about the future of surgery in the post-COVID-19 era. The COVID-19 pandemic is severely damaging surgical training. The establishment of a multidisciplinary ethics committee should be encouraged at all surgical oncology centres. Innovative leadership and collaboration is vital in the post-COVID-19 era

Hormonal and inflammatory modulatory effects of hesperidin in hyperthyroidism-modeled rats

The goal of the current study was to investigate the hormonal modulatory efficiency of hesperidin, through its regulatory potential of immunological, inflammatory, and/or antioxidant changes in on hyperthyroidism modeled adult female albino rats. Both normal and hyperthyroidism modeled rats (140-160g) were randomly divided into four groups (10 animals each) as follows: 1) healthy animals were daily ingested with saline for six weeks, and served as control group, 2) healthy animals were intraperitoneally injected with hesperidin (50 mg/kg/day) for a similar period, 3) hyperthyroidism-modeled animals without any treatment acted as positive control, and 4) hyperthyroidism-modeled animals were treated intraperitoneally with hesperidin for a similar period. The findings showed that hesperidin significantly modulated hyperthyroidism deteriorations, this was evidenced by a remarkable decline in serum T4, FT4, T3, FT3, TNF-α, IL1β-, IL4-, IL-6, and IL-10 levels, with a minor increase in TSH and significant raise in CD4+ level. Similarly, valuable improvement was observed in the oxidative status; serum SOD, GPx, CAT, and GSH levels were dramatically enhanced, associated with remarkable drop in MDA and NO levels. Also, hesperidin demonstrated nephro-hepatoprotective and anti-atherogenic potential, this was achieved from the notable reduction in ALAT and ASAT activities as well as urea, creatinine, cholesterol, and triglyceride close to the corresponding values of healthy group. These findings were supported by histological and immunohistochemical ones that showed a notable decrease in the expression of the calcitonin antibody. In conclusion, hesperidin possesses anti-hyperthyroidism, immunoinflammatory regulatory, and antioxidant activities that evidenced from the improvement of physio-architecture of the thyroid gland, reduction of inflammation and restoration of the impaired oxidative stress. This effect might be mechanized through immunological, inflammatory, apoptotic, and/or antioxidant modulatory pathways

Inhibitive action of gramine towards corrosion of mild steel in deaerated 1.0 M hydrochloric acid solutions

The effect of addition of gramine on mild steel dissolution in deaerated 1.0 M hydrochloric acid was studied through potentiodynamic polarisation curves, electrochemical impedance spectroscopy and gravimetric measurements in the temperature range from 25 °C to 55 °C. Gramine was found to shift the corrosion potentials towards less noble values and decrease both dissolution of mild steel and hydrogen evolution reaction. Gramine did not affect the corrosion reaction mechanism (blocking effect). Results obtained from the several measurement techniques were in good agreement and revealed good inhibition efficiencies in the concentration range (0.75 mM ÷ 7.5 mM) particularly at higher concentrations