Factors Affecting Coronary Flow in Children

Factors Affecting Coronary Flow in Children Elhadi H. Aburawi, MD, MSc, FRCPI, FRCPCH Division of Paediatric Cardiology, Department of Paediatrics, Lund University, Sweden Abstract Background: A number of inborn and exogenous factors influence the flow and function of the coronary arteries with possible consequences on the cardiovascular risk. The regulation of the coronary flow is partly dependent on the functional integrity of coronary endothelial cells, coronary perfusion pressure, and myocardial function. Objectives: To investigate the effects of some of the previously suggested cardiovascular risk factors on coronary flow and function in children. Methods: Blood lipid pattern and concentration of acute phase proteins and their relation to prior infections were studied. The effect of preceding airway infections on the endothelium-dependent vasomotor function of the brachial artery in healthy and type 1 diabetes mellitus children was assessed. Coronary flow was measured with transthoracic Doppler echocardiography before and after non-surgical and surgical treatment of congenital heart defects. Results: Pro-atherogenic changes consisting of decreased circulating levels of high density lipoprotein and albumin were observed in children with past infections. The brachial artery's endothelial vasomotor function was impaired in children with type 1 diabetes, being further affected by preceding mild infections in the upper airways. Compared to controls, coronary flow was increased in patients with left-to-right shunt and coarctation of aorta, and increased further after open heart surgery. In contrast, coronary flow decreased, even if not to normal, after coarctectomy and device closure of atrial septal defect. Cardiac output decreased after open heart surgery but improved after device closure. The coronary flow velocity and velocity time integral decreased with increasing CRP after open heart surgery in particular in those with prolonged aortic cross clamping. Conclusions: Residual pro-atherogenic disturbances in vascular endothelial function, lipid and albumin metabolism may be observed in children with past infections, especially in those with chronic cardiovascular risk factors such as diabetes mellitus. Cardiac malformations and open heart surgery affect negatively the coronary blood flow and cardiac output. LIST OF PUBLICATIONS This thesis is based on the following papers, which will be referred to by the Arabic numerals: 1. Aburawi EH, Grubb A, Raitakari O, Viikari J, Pesonen E. Lowered levels of serum albumin and HDL-cholesterol in children with a recent mild infection. Annals of Medicine. 2006;38:154-160. 2. Aburawi EH, Liuba P, Pesonen E, Yla-Herttuala S, Sjoblad S. Acute respiratory viral infections aggravate arterial endothelial dysfunction in children with type 1 diabetes. Diabetes Care. 2004;27:2733-5. 3. Aburawi EH, Berg A, Liuba P, Pesonen E. Effects of cardio-pulmonary bypass surgery on coronary flow in children assessed with transthoracic Doppler echocardiography. Am J Physiol Heart Circ physiol. 2007 May 4, (Epub ahead of print) 4. Aburawi EH, Berg A, Pesonen E. Coronary blood flow in patients with atrial septal defect before and after surgical versus device closure A transthoracic Doppler echocardiography study. (Submitted to Circulation). 5. Aburawi EH, Liuba P, Berg A, Pesonen E. C-reactive protein and coronary microcirculation in children after open heart surgery A transtoracic Doppler echocardiography study. Cardiology in the Young (in press)

Analysis of non-performing loans in the Libyan state-owned commercial banks: perception analysis of the reasons and potential methods for treatment.

Granting loans and credit facilities is considered as the main function of commercial banks in terms of providing liquidity to their clients on one hand, and achieving a sufficient profit for themselves on the other. In the credit facilities offered by the banks, when clients fail to pay their obligations, banks are exposed to non-performing loans. Similar to any other financial system, Libyan financial the questionnaires' respondents system is also faced with non-performing loans in particular in the Libyan state-owned commercial banking sector. This study, hence, aims to identify the non-performing loans in the Libyan stated owned commercial banking but also aims to determine the main types of loans and the reasons which led to non-performing loans in the Libyan state-owned commercial banks. In addition, this study aims to locate the appropriate ways which may be used to treat non-performing loans in the Libyan state-owned commercial banks. These aims are fulfilled through the perceptions and opinions of staff working in various levels in Libyan state-owned commercial banks.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Effects Of Aging, Temperature, Moist Aggregates And Filler Type On Performance Of Warm Mix Asphalt Incorporating Rh-Wma Additive

Conventional Hot Mix Asphalt (HMA) has been the primary material used in pavement in past decades. Recently, compared to conventional HMA, Warm Mix Asphalt (WMA) has shown great potential and offers benefits not given by HMA, since the WMA can be produced at lower temperatures without affecting pavement performance. Since WMA additives can reduce the binder viscosity, the production and compaction temperatures can be lowered, compared to conventional HMA. One of the additives used to produce WMA is a type of wax named RH-WMA. In this thesis, the rheological properties of a conventional a virgin PG64 asphalt binder with and without RH-WMA at different aging conditions were investigated. The overall rheological binder tests results indicated that RH-WMA content had significant effects on the rheological parameters of asphalt binders in terms of viscosity, G*/sin δ and G*sin δ. Image analysis technique was used to classify the adhesive failure by using impact test. The impact test was conducted on a newly fabricated mould and the effects of aging conditions and test temperatures of asphalt binder incorporating RH-WMA were investigated. The analysis results showed that short-term aging and long-term aging of asphalt binder increased the percentage of adhesion failure. The construction temperature (mixing and compaction) was reduced by the addition of RH-WMA additive due to viscosity reduction. However, the reduction of mixing temperatures may prevent moisture from being completely evaporated from the aggregate and thus, effect the asphalt binder bond, making the mixture more susceptible to stripping. Two anti-stripping additives, namely hydrated lime and Pavement Modifier (PMD) were used to reduce the destructive effects of moisture. Effects of RH-WMA content, production and testing temperatures on mixture performance were investigated in terms of indirect tensile strength, resilient modulus and creep stiffness. The result indicates that both ITS and MR decreased as the RH-WMA content increased at the respective test and mixing temperatures. The effects of incomplete drying of aggregates on the mechanical properties of asphalt mixtures were clearly evident in this thesis. Therefore, the use of fully dried aggregates was important in ensuring satisfactory mix performance. Mixes prepared with 3% RH-WMA and compacted at 125°C° exhibit the best performance compare with HMA. Specimen incorporating PMD filler improved resistance to stripping compared to mixes with hydrated lime filler regardless of compaction temperature. The test results also indicated that aging improved the moisture resistance of WMA

The Burden of Congenital Heart Disease in Libya

Congenital Heart Disease (CHD) is defined as a gross structural abnormality of the heart or intrathoracic great vessels that is actually or potentially of functional significance. It is the most common congenital problem that account for up to 25% of all congenital malformations that present in the neonatal period [1]. The cause of CHD is multifactorial. Early diagnosis and proper and early medical or surgical intervention for most of the CHD could provide anatomical correction and normal life expectancy. Patients born with severe forms of CHD are at approximately 12 times higher risk of mortality in the first year of life, particularly if they are missed in the neonatal period. Mortality in the first year of life was 18% for all CHD that are diagnosed in infancy [2]. Cardiac surgery with poor setup could have a higher mortality than leaving them alone

Evaluation of Faculty : Are medical students and faculty on the same page?

Objectives: Student evaluation of individual teachers is important in the quality improvement cycle. The aim of this study was to explore medical student and faculty perceptions of teacher evaluation in the light of dwindling participation in online evaluations. Methods: This study was conducted at the United Arab Emirates University College of Medicine & Health Sciences between September 2010 and June 2011. A 21-item questionnaire was used to investigate learner and faculty perceptions of teacher evaluation in terms of purpose, etiquette, confidentiality and outcome on a five-point Likert scale. Results: The questionnaire was completed by 54% of faculty and 23% of students. Faculty and students generally concurred that teachers should be evaluated by students but believed that the purpose of the evaluation should be explained. Despite acknowledging the confidentiality of online evaluation, faculty members were less sure that they would not recognise individual comments. While students perceived that the culture allowed objective evaluation, faculty members were less convinced. Although teachers claimed to take evaluation seriously, with Medical Sciences faculty members in particular indicating that they changed their teaching as a result of feedback, students were unsure whether teachers responded to feedback. Conclusion: Despite agreement on the value of evaluation, differences between faculty and student perceptions emerged in terms of confidentiality and whether evaluation led to improved practice. Educating both teachers and learners regarding the purpose of evaluation as a transparent process for quality improvement is imperative

Genotoxic effect induced by hydrogen peroxide in human hepatoma cells using comet assay

Background: Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is a common reactive oxygen intermediate generated by various forms of oxidative stress. Aim: The aim of this study was to investigate the DNA damage capacity of H<sub>2</sub>O<sub>2</sub> in HepG2 cells. Methods: Cells were treated with H<sub>2</sub>O<sub>2</sub> at concentrations of 25 mM or 50 mM for 5 min, 30 min, 40 min, 1 h, or 24 h in parallel. The extent of DNA damage was assessed by the comet assay. Results: Compared to the control, DNA damage by 25 and 50 mM H<sub>2</sub>O<sub>2</sub> increased significantly with increasing incubation time up to 1 h, but it was not increased at 24 h. Conclusions: Our findings confirm that H<sub>2</sub>O<sub>2</sub> is a typical DNA damage-inducing agent and thus is a good model system to study the effects of oxidative stress. DNA damage in HepG2 cells increased significantly with H<sub>2</sub>O<sub>2</sub> concentration and time of incubation but later decreased likely due to DNA repair mechanisms and antioxidant enzymes.Keywords: DNA damage; hydrogen peroxide; HepG2 cells; comet assa

Development of Arnold's Humanistic Thinking

Englis

System dynamics modelling for human resource planning.

The research undertaken in this thesis concerns the application of system dynamics to the field of Human Resource Planning (HRP). Human resource planning has been defined as the process whereby a company develops and deploys the right staff at the right places, at the right times to fulfil both organization and individual objectives. In this process staff are recruited and trained before they can contribute to an organisation's goals. Recruitment and training of new staff needs to be carefully planned to prevent staff shortages or staff surpluses. Such planning, in turn, very often makes use of models, and the aim of this research is to show that the application of system dynamics can be used to produce effective models for use in human resource planning. The models developed build on the Inventory and Order Based Production Control Systems (IOBPCS) work of Towill (1982) and extend the work of Hafeez (2000), who applied these IOBPCS ideas to skill pool modelling in human resource management. The models developed in this thesis provide companies with the means of producing optimum HRP strategies. In total four new models are developed: SKPM (basic Skill Pool Model), APSKPM (Automated Pipeline Skill Pool Model), APSKPM+(P+I), (Automated Pipeline Skill Pool Model plus Proportional and Integral controller), and a PPSKPM (Progression and Promotion Skill Pool Model). In each case the models are developed in terms of control parameters that relate to aspects of the human resource planning process that can be controlled by the human resource manager or decision maker. Using computer simulation the dynamic behaviour of the human resource systems represented by the models is determined over time for any given set of control parameters. By varying the parameters in a systematic way optimal models are produced to aid the decision maker. Any set of parameters represents an HRP strategy and, by using simulation, system dynamics can be seen to furnish optimal human resource planning policies for the decision maker. In the thesis the models are systematically tested with real data relating to the Libyan petrochemical industry. Data from two case companies are used in this testing. The case-company testing demonstrates that system dynamics can be used to create effective models for use in human resource planning and shows also the same relationship between control parameters that was found in the work of Towill and Hafeez