Fluid shear stress modulation of hepatocyte like cell function

Freshly isolated human adult hepatocytes are considered to be the gold standard tool for in vitro studies. However, primary hepatocyte scarcity, cell cycle arrest and the rapid loss of cell phenotype limit their widespread deployment. Human embryonic stem cells and induced pluripotent stem cells provide renewable sources of hepatocyte-like cells (HLCs). Despite the use of various differentiation methodologies, HLCs like primary human hepatocytes exhibit unstable phenotype in culture. It has been shown that the functional capacity can be improved by adding back elements of human physiology, such as cell co-culture or through the use of natural and/or synthetic surfaces. In this study, the effect of fluid shear stress on HLC performance was investigated. We studied two important liver functions, cytochrome P450 drug metabolism and serum protein secretion, in static cultures and those exposed to fluid shear stress. Our study demonstrates that fluid shear stress improved Cyp1A2 activity by approximately fivefold. This was paralleled by an approximate ninefold increase in sensitivity to a drug, primarily metabolised by Cyp2D6. In addition to metabolic capacity, fluid shear stress also improved hepatocyte phenotype with an approximate fourfold reduction in the secretion of a foetal marker, alpha-fetoprotein. We believe these studies highlight the importance of introducing physiologic cues in cell-based models to improve somatic cell phenotype

Healthcare finance in the Kingdom of Saudi Arabia:a qualitative study of householders’ attitudes

Background: The public sector healthcare system in Saudi Arabia, essentially financed by oil revenues and ‘free at the point of delivery’, is coming under increasing strain due to escalating expenditure and an increasingly volatile oil market and is likely to be unsustainable in the medium to long term. Objectives: This study examines how satisfied the Saudi people are with their public sector healthcare services and assesses their willingness to contribute to financing the system through a national health insurance scheme. The study also examines public preferences and expectations of a future national health insurance system. Methods: A total of 36 heads of households participated in face-to-face audio-recorded semi-structured interviews. The participants were purposefully selected based on different socio-economic and socio-demographic factors from urban and rural areas to represent the geographical diversity that would presumably influence individual views, expectations, preferences and healthcare experiences. Results: The evidence showed some dissatisfaction with the provision and quality of current public sector healthcare services, including the availability of appointments, waiting times and the availability of drugs. The households indicated a willingness to contribute to a national insurance scheme, conditional upon improvements in the quality of public sector healthcare services. The results also revealed a variety of preferences and expectations regarding the proposed national health insurance scheme. Conclusions: Quality improvement is a key factor that could motivate the Saudi people to contribute to financing the healthcare system. A new authority, consisting of a partnership between the public and private sectors under government supervision, could represent an acceptable option for addressing the variation in public preferences

Investigating the Willingness to Pay for a Contributory National Health Insurance Scheme in Saudi Arabia:A Cross-sectional Stated Preference Approach

Background: The Saudi Healthcare System is universal, financed entirely from government revenue principally derived from oil, and is ‘free at the point of delivery’ (non-contributory). However, this system is unlikely to be sustainable in the medium to long term. This study investigates the feasibility and acceptability of healthcare financing reform by examining households’ willingness to pay (WTP) for a contributory national health insurance scheme. Methods: Using the contingent valuation method, a pre-tested interviewer-administered questionnaire was used to collect data from 1187 heads of household in Jeddah province over a 5-month period. Multi-stage sampling was employed to select the study sample. Using a double-bounded dichotomous choice with the follow-up elicitation method, respondents were asked to state their WTP for a hypothetical contributory national health insurance scheme. Tobit regression analysis was used to examine the factors associated with WTP and assess the construct validity of elicited WTP. Results: Over two-thirds (69.6%) indicated that they were willing to participate in and pay for a contributory national health insurance scheme. The mean WTP was 50 Saudi Riyal (US$13.33) per household member per month. Tobit regression analysis showed that household size, satisfaction with the quality of public healthcare services, perceptions about financing healthcare, education and income were the main determinants of WTP. Conclusions: This study demonstrates a theoretically valid WTP for a contributory national health insurance scheme by Saudi people. The research shows that willingness to participate in and pay for a contributory national health insurance scheme depends on participant characteristics. Identifying and understanding the main influencing factors associated with WTP are important to help facilitate establishing and implementing the national health insurance scheme. The results could assist policy-makers to develop and set insurance premiums, thus providing an additional source of healthcare financing

Mechanical characterization of aged AA2026-AA2026 overcast joints fabricated by squeeze casting

Squeeze overcasting has emerged as an attractive option for casting of Al alloys in terms of mechanical properties. The attainment of the desired magnitude of these properties is challenging in overcasting due to the involvement of a number of process parameters. In this study, the effects of insert preheat temperature (TI) along with pouring temperature (TP), and squeeze pressure (PS) on the mechanical properties of squeeze overcast AA2026-AA2026 joint were investigated. Experimental results revealed that the squeeze pressure is the most prominent factor affecting the ultimate tensile strength (UTS) while micro-hardness (MH) is significantly influenced by the pouring temperature. Maximum values of UTS (315 MPa) and MH (130 HV) were achieved at a PS of 120 MPa, TP of 780 °C, and TI of 250 °C. Energy dispersive X-ray (EDX) analysis witnessed that TI has also a significant role in determining the quality of bond between the substrate and the melt. Scanning electron microscopy (SEM) depicts that the morphology of the fractured surface has a sound influence on both selected responses. Both the strength and hardness are noticed better if the fractured surface possesses the flat-faced morphology. Furthermore, an empirical regression model was developed using response surface methodology (RSM) design and validated through eight confirmatory experiments. RSM integrated multi-objective optimization genetic algorithm (MO-GA) was deployed to optimize the UTS and MH. The comparative results obtained from RSM and MO-GA demonstrated that the deviation in experimental and predicted values is less than 5%