Intima-Media Thickness and Pulse Wave Velocity in Hypertensive Adolescents

Increased intima-media thickness (IMT) and pulse wave velocity (PWV) are noninvasive markers of early arterial wall alteration and are more widely used in adult clinical research. We investigated whether IMT and PWV are useful predictors of cardiovascular risk in hypertensive adolescents. Fifteen hypertensive adolescents (13-18 yr old, systolic BP ≥140 mmHg, diastolic BP ≥90 mmHg) and seventeen normotensive subjects were included. Height, weight, obesity index, body mass index (BMI), and fat distribution were obtained from each group. Serum lipid, insulin, vitamine B12, folate, renin, aldosterone, angiotensin-converting enzyme (ACE), and homocysteine levels were compared. The carotid IMT and PWV were measured. Arterial wall compliance and distensibility were calculated with the equation. High systolic blood pressure significantly correlated with height, weight, BMI, obesity index, arm circumference, fat mass, and fat distribution. Hypertensive adolescents had significantly greater cIMT (carotid intima-media thickness) and lower elastic properties such as cross-sectional compliance and distensibility of the carotid artery. The carotid IMT significantly correlated with brachial-ankle PWV. In conclusion, the measurement of carotid IMT and brachial-ankle PWV might be useful to predict the development of atherosclerosis in hypertensive adolescents

Aneurysmal disease is associated with lower carotid intima-media thickness than occlusive arterial disease

Objective: Patients with aneurysmal and occlusive arterial disease have overlapping cardiovascular risk profiles. The question remains how atherosclerosis is related to the formation of aortic aneurysms. Common carotid artery intima-media thickness (CIMT) is an easily accessible and objective marker of early atherosclerosis. The aim of the current study was to investigate whether there is a difference in atherosclerotic burden as measured by CIMT between patients with aneurysmal and those with occlusive arterial disease. Methods: From 2004 to 2011, the CIMT was measured using B-mode ultrasound scanning in patients undergoing vascular surgery for aortic aneurysmal or occlusive arterial disease at the Erasmus University Medical Center. Cardiovascular risk factors, comorbidities, and medication were recorded. Patients treated for combined aneurysmal and occlusive arterial disease and patients diagnosed with a genetic aneurysm syndrome were excluded. Univariable and multivariable analyses wer

Cardiac and vascular structure and function parameters do not improve with alternate nightly home hemodialysis: An interventional cohort study

Background: Nightly extended hours hemodialysis may improve left ventricular hypertrophy and function and endothelial function but presents problems of sustainability and increased cost. The effect of alternate nightly home hemodialysis (NHD) on cardiovascular structure and function is not known

Kesikli zaman-maliyet ödünleşim problemlerinde pareto eğrisinin melez kuş sürüsü optimizasyon algoritması ile oluşturulması.

In pursuance of decreasing costs, both the client and the contractor would strive to speed up the construction project. However, accelerating the project schedule will impose additional cost and might be profitable up to a certain limit. Paramount for construction management, analyses of this trade-off between duration and cost is hailed as the time-cost trade-off (TCT) optimization. Inadequacies of existing commercial software packages for such analyses tied with eminence of discretization, motivated development of different paradigms of particle swarm optimizers (PSO) for three extensions of discrete TCT problems (DTCTPs). A sole-PSO algorithm for concomitant minimization of time and cost is proposed which involves minimal adjustments to shift focus to the completion deadline problem. A hybrid model is also developed to unravel the time-cost curve extension of DCTCPs. Engaging novel principles for evaluation of cost-slopes, and pbest/gbest positions, the hybrid SAM-PSO model combines complementary strengths of overhauled versions of the Siemens Approximation Method (SAM) and the PSO algorithm. Effectiveness and efficiency of the proposed algorithms are validated employing instances derived from the literature. Throughout computational experiments, mixed integer programming technique is implemented to introduce the optimal non-dominated fronts of two specific benchmark problems for the very first time in the literature. Another chief contribution of this thesis can be depicted as potency of SAM-PSO model in locating the entire Pareto fronts of the practiced instances, within acceptable time-frames with reasonable deviations from the optima. Possible further improvements and applications of SAM-PSO model are suggested in the conclusion.M.S. - Master of Scienc

Improvement of performance propertİes of bİtumen and bİtumİneous mİxtures by addİng sugar beet molasses

Birçok ülkede de Türkiye gibi esnek üstyapılar en çok tercih edilen üstyapı türüdür. Esnek üstyapılarda kullanılan malzemelerin özelliğinden dolayı yapım ve onarım maliyeti oldukça pahalıdır. Maliyetlerin yüksek ve çok önem taşıdığından, bir diğer taraftan araç trafiğinin her gecen gün artmasından dolayı esnek üstyapı uygulama doğrultusunda muazzam yatırımlar yapılması gerekmektedir. Barizdir ki atık olarak elde edilen çeşitli ürünlerin doğaya terk edilmesi çevre kirliliği gibi büyük sorunlar getirmektedir. Günümüzde, çeşitli ürünlerin üretimi sırasında elde edilen yan ürün veya atıkların değerlendirilmesi üzerine çeşitli çalışmalar yapılmaktadır. Atıklar, yeni ürünlerin elde edilmesinde veya mevcut ürünlerde katkı maddesi olarak kullanılabilmektedir. Atık malzeme ve yan ürünlerin değerlendirilmesi çok kısıtlı olan doğal malzemelerin kullanımını azaltarak doğanın tahrip edilmesini önler ve diğer yandan malzemelerin atılmak üzere depolanmasını önleyerek çevrede oluşacak problemleri en aza indirilmesini sağlar. Son yıllarda, endüstriyel atıkların karayolu tabakalarında değerlendirerek ortadan kaldırılmaları için yapılan çalışmalar yaygınlaşmıştır. Şeker fabrikalarında şeker pancarı veya şeker kamışından şeker elde edilirken oluşan koyu, zor akıcı, suda çözülebilen ve karbonhidrat bakımından zengin şeker sanayi yan ürünü olan melas, katkı maddesi olarak bitüme ilave edilmesiyle bitümün reolojik özelliklerinin geliştirilmesi amacıyla kullanılabilmektedir. Aynı doğrultuda, bu çalışmanın asıl amacı şeker pancarı melası ve melasa boroksiti ilave ederek (MEBSA) iki farklı katkı maddesi elde edildikten sonra bitümle karışımında, karışımın performansının artmasını sağlamaktır. Bu çalışmada melas ve boroksitle melasın karışımı, MEBSAyı adım adım % 1, 2, 3, 5, 7,5 ve 10 oranlarında bitümle karıştırılarak katkılı numuneler üretilmiştir. Bitümün reolojik özelliklerinin belirlenmesi için orjinal ve modifiye edilen bitüm örneklerine Brookfield viskozimetre cihazıyla viskozite deneyi yapılmış ve optimum viskozite değerleri belirlenerek, elde edilen modifiye bitüm ve katkısız saf bitüm örneklerine penetrasyon, yumuşama noktası ve bitümlü karışımların performanslarıyla ilgili Marshall stabilitesi ve soyulma deneyleri uygulanmıştır. Bunların yanı sıra, katkı maddeleri bitümlü sıcak karışımların üretim ve uygulama süreçlerinde enerji tasarrufuna yol açması, bitümün kısa dönem yaşlanmasının azalması ve işlenebilirliğin artması gibi faktörler göz önüne alınarak incelenmiştir. Son olarak maliyet açısından melas ve melas esaslı boroksit içeren katkı maddeleri, polimer kökenli Stiren Butadien Stiren'le kıyaslanarak, bitümlü sıcak karışımların fiyat/ton üzerindeki etkileri analiz edilmiştir.As in Turkey, in many other countries the most prevalent and preferred type of superstructure is observed to be the flexible pavements. Due to the special properties of materials used in the flexible pavements, costs pertinent to both construction and maintenance are quite exorbitant. Owing to important, yet, costly investments, besides, because of the incessant growth in traffic volume, implementation of flexible pavements necessitates substantial funding. It is obvious that disposal of various waste products in the nature would yield major problems including environmental pollution. Thus, numerous studies in several different contexts have hitherto been conducted to address application of by-products or waste products that are produced during or as a result of diverse manufacturing processes. Wastes are being used to produce novel products or are applied as additives to the existing ones. Treatment of by-products and waste products not only reduces application of scarce natural resources, but also prevents accumulation of materials intended to dump, which in turn impedes environmental destruction. In recent years, for the sake of waste elimination, a tendency toward utilization of industrial waste in preparation of road layers has emerged. Being a by-product of sugar mills, molasses is a dark, viscous, water-soluble, and carbohydrate-rich substance obtained from either sugar beets or cane sugar. This by-product is being added to bitumen as an additive in order to improve its rheological properties. In the same direction, the ultimate resolution of this study is to enhance performance of bitumen and bituminous mixtures by adding two different additives of sugar beet molasses and mixture of molasses and boric-oxide (hailed as MEBSA). In the course of this study, different samples containing varied percentages of additives were prepared. For both molasses and MEBSA, samples were prepared by gradually increasing the percentage of additives in the bitumen as 1, 2, 3, 5, 7.5 and 10 percent. Experimentations on efficacy evaluation of the aforestated additives on the rheology of the bitumen were initiated by conducting viscosity tests, carried out by the Brookfield Viscometer. Ensuing identification of the optimum viscosity ratios, comparisons among the original bitumen and bituminous mixtures were carried out through exertion of penetration tests, softening point tests, ductility tests and performance related tests such as Marshall Stability and stripping resistance tests. Furthermore, efficiency of the noted additives throughout both preparation and application processes of bituminous hot mixtures have been investigated with regard to some additional criteria, viz., energy saving, short-term aging of bitumen, and their workability. Ultimately, cost analyses were carried out to compare unit-prices of both the molasses and MEBSA additives to that of Styrene Butadiene Styrene, and to assess their impact on price per ton of asphalt mixtures

Pareto oriented optimization of discrete time cost trade off problem using particle swarm optimization

In project scheduling, it is feasible to reduce the duration of a project by allocating additional resources to its activities. However, crashing the project schedule will impose additional costs. Numerous research has focused on optimizing the trade-off between time and cost to achieve a set of non-dominated solutions. However, the majority of the research on time-cost trade-off problem developed methods for relatively simple problems including up to eighteen activities, which are not representing the complexity of real-life construction projects. In this work a Particle Swarm Optimization (PSO) technique is presented for Pareto oriented optimization of the complex discrete time-cost trade-off problems. The proposed PSO engages novel principles for representation and position-updating of the particles. The performance of the PSO is compared to the existing methods using a well-known 18-activity benchmark problem. A 63-activity problem is also included in computational experiments to validate the efficiency and effectiveness of the proposed PSO for a more complex problem. The results indicate that the proposed method provides a powerful alternative for the Pareto front optimization of DTCTPs

Discrete particle swarm optimization method for the large-scale discrete time-cost trade-off problem

Despite many research studies have concentrated on designing heuristic and meta-heuristic methods for the discrete time-cost trade-off problem (DTCTP), very little success has been achieved in solving large-scale instances. This paper presents a discrete particle swarm optimization (DPSO) to achieve an effective method for the large-scale DTCTP. The proposed DPSO is based on the novel principles for representation, initialization and position-updating of the particles, and brings several benefits for solving the DTCTP, such as an adequate representation of the discrete search space, and enhanced optimization capabilities due to improved quality of the initial swarm. The computational experiment results reveal that the new method outperforms the state-of-the-art methods, both in terms of the solution quality and computation time, especially for medium and large-scale problems. High quality solutions with minor deviations from the global optima are achieved within seconds, for the first time for instances including up to 630 activities. The main contribution of the proposed particle swarm optimization method is that it provides high quality solutions for the time-cost optimization of large size projects within seconds, and enables optimal planning of real-life-size projects

Pareto Front Particle Swarm Optimizer for Discrete Time-Cost Trade-Off Problem

Intensive heuristic and metaheuristic research efforts have focused on the Pareto front optimization of discrete time-cost trade-off problem (DTCTP). However, very little success has been achieved in solving the problem for medium and large-scale projects. This paper presents a new particle swarm optimization method to achieve an advancement in the Pareto front optimization of medium and large-scale construction projects. The proposed Pareto front particle swarm optimizer (PFPSO) is based on a multiobjective optimization environment with novel particle representation, initialization, and position-updating principles that are specifically designed for simultaneous time-cost optimization of large-scale projects. PFPSO brings several benefits for the discrete time-cost optimization, such as an adequate representation of the discrete search space, fast convergence properties, and improved Pareto front optimization capabilities. The computational experiment results reveal that the new particle swarm optimization method outperforms the state-of-the-art methods, both in terms of the number of Pareto front solutions and computation time, especially for medium and large-scale problems. A large number of nondominated solutions are achieved within seconds for the first time, for a problem including 720 activities. The proposed Pareto front particle swarm optimizer provides a fast and effective method for optimal scheduling of construction projects. (C) 2016 American Society of Civil Engineers