This paper deals with the problem of bypass surgery. It examines the basic mechanical and physiological problems of the heart and lung. The paper reveals that the cardio pulmonary bypass is a technique by which the pumping action of the heart and the gas exchange functions of the lung are temporally replaced by a mechanical device, the pump oxygenator attached to the vascular system of the patients. Studies have been carried out on over 250 patients on open heart operations and clinical perfusion of the cardio pulmonary bypass. The contributions of this paper are based on the results obtained from successful patient’s operations models of pre-operative and post operative procedures. The paper revealed that patients with angina pectoris stenosis complications in heart attack and young individuals with heart diseases need CPB. The result indicates that the CPB is relatively safe, in the sense that many patients got relieved from the intra-cardiac and excruciating pains. The new trend is that the study identified by passes surgery as one of the greatest contributions grouped in line with the discovery of antibiotics and insulin with regards to the health care system.\nThe method is useful in the sense that it has prevented many early deaths and has helped innumerable patients to live normal lives. The limitation is that only certain persons can benefit from these procedures.

This work examines how friction coefficient and wear rate are affected by normal load and sliding velocity. Variations of friction coefficient and wear rate with the variation of normal load are experimentally investigated. Experiments are also conducted to study the effect of sliding velocity on friction and wear. The effects of duration of rubbing on friction for different materials under different operating conditions are also investigated in this research work. Experiments are carried out by sliding a stainless steel pin on different types of material such as gun metal and brake shoe material (asbestos fiber). To do so a pin on disc apparatus is used. \nExperiments are carried out for normal load ranging from 10.0 to 20.0 N and sliding velocity ranging from 1 to 3 m/s. In each experiment, the duration of rubbing is maintained for 30 minutes. During study, the original commercially available roughness of gun metal (0.50 - 0.60 ) and brake shoe material (5.00 – 6.00 ) are maintained.\nStudies have shown that the values of friction coefficient and wear rate depend on normal load and sliding velocity. It is observed that the friction coefficient and wear rate of brake shoe material are increased with the increase of sliding velocity and normal load. Experimental results also reveal that the friction coefficient decreases and wear rate increases with the increase of sliding velocity and normal load for gun metal. The rates of increment are different for different types of material. It is also found that friction coefficient varies with the duration of rubbing and this variation is different for different materials. The experimental results are compared with those available in the literature.

Water measurements play a pivotal role in hydraulic and environmental management. The structures used for flow measurements should be accurate, economical and easy to use (installation, operation and maintenance). There are different types of structures available for flow measurements such as weirs, orifice, flumes, sluice gates etc. Due to effective limitations of simple sharp crested weirs, recently compound sharp crested weirs have attracted great attention of civil engineers. By this type of weirs, flow discharge is measured with a reasonable sensitivity over a wide range of flow rates. The aim of this research is numerical investigation of flow characters on compound arched rectangular sharp crested weir using FLUENT software in three-dimensional environment. For multiphase flow simulation, Volume of Fluid method is used and for simulation of turbulent flow, RNG k-ɛ turbulence model is used and the result of numerical model is compared with experimental data. The results of this study indicate that; FLUENT software simulate flow on compound arched rectangular sharp crested weir with high accuracy and the relative error of water depth in upstream of the weir for numerical models, was less than 3.07%.

Alveoli are hollow cavitites within the human body. In the present study, alveoli of\nhuman lungs are considered which are healthy and also when affected by emphysema −\nloss of elasticity resulting in breathing difficulties. It is interesting to apply graph theory\nwith a view to test and predict the status of alveoli in both healthy lungs and when\naffected. The model developed can be used for further advancement in the medical\nfield for any diagnosis with respect to the lung diseases. In the current paper, the\nauthors have attempted to use double graphs by considering the alveoli as a connected\ngraph. Topological indices are determined for healthy and ruptured alveoli by using\ngraph operator called double graphs.

Background\nThe use of stem cells in regenerative medicine has major therapeutic potential. Recent clinical trials using cells derived from human stem cells are showing encouraging results, although these should be assessed with the necessary caution. \nDiscussion\nSome media have reported the results of these trials without due care, perhaps creating expectations that do not match the reality of the facts. This paper describes some of the recent advances in the use of human stem cells, particularly those made in the area of ophthalmology, and more specifically, in Stargardt\'s disease and age-related macular degeneration (AMD).\nWe also present promising studies with induced pluripotent stem (iPS) cells, aimed at obtaining retinal pigmented epithelium and light-sensitive retinal rods in the aforementioned ocular diseases, with encouraging preclinical and clinical results.

In this research, the relationships between corporate governance, systematic risk and firm’s performance in Tehran Stock Exchange are investigated. Research data for 2004 to 2012 is compiled using RahavardNowin software and TSE database. Systematic risk is calculated through beta factor of Capital Asset Pricing Model (CAPM). Corporate governance proxies in this study are board’s member number, outside board of director, board’s duality, audit quality and institutional ownership. In addition, four measures of Tobin’s Q, equity price to cash flow, equity price to revenue and equity price to sale are used to measure firm’s performance. Fife control variables of financial leverage, firm’s size, profitability and firm’s life cycle are considered in this research. The results of hypotheses test indicate that there is not a significant relationship between corporate governance and systematic risk and also between systematic risk and firm’s performance.