Image based approach for early assessment of heart failure.

In diagnosing heart diseases, the estimation of cardiac performance indices requires accurate segmentation of the left ventricle (LV) wall from cine cardiac magnetic resonance (CMR) images. MR imaging is noninvasive and generates clear images; however, it is impractical to manually process the huge number of images generated to calculate the performance indices. In this dissertation, we introduce a novel, fast, robust, bi-directional coupled parametric deformable models that are capable of segmenting the LV wall borders using first- and second-order visual appearance features. These features are embedded in a new stochastic external force that preserves the topology of the LV wall to track the evolution of the parametric deformable models control points. We tested the proposed segmentation approach on 15 data sets in 6 infarction patients using the Dice similarity coefficient (DSC) and the average distance (AD) between the ground truth and automated segmentation contours. Our approach achieves a mean DSC value of 0.926±0.022 and mean AD value of 2.16±0.60 mm compared to two other level set methods that achieve mean DSC values of 0.904±0.033 and 0.885±0.02; and mean AD values of 2.86±1.35 mm and 5.72±4.70 mm, respectively. Also, a novel framework for assessing both 3D functional strain and wall thickening from 4D cine cardiac magnetic resonance imaging (CCMR) is introduced. The introduced approach is primarily based on using geometrical features to track the LV wall during the cardiac cycle. The 4D tracking approach consists of the following two main steps: (i) Initially, the surface points on the LV wall are tracked by solving a 3D Laplace equation between two subsequent LV surfaces; and (ii) Secondly, the locations of the tracked LV surface points are iteratively adjusted through an energy minimization cost function using a generalized Gauss-Markov random field (GGMRF) image model in order to remove inconsistencies and preserve the anatomy of the heart wall during the tracking process. Then the circumferential strains are straight forward calculated from the location of the tracked LV surface points. In addition, myocardial wall thickening is estimated by co-allocation of the corresponding points, or matches between the endocardium and epicardium surfaces of the LV wall using the solution of the 3D laplace equation. Experimental results on in vivo data confirm the accuracy and robustness of our method. Moreover, the comparison results demonstrate that our approach outperforms 2D wall thickening estimation approaches

The dividend payout policy - a study on Malaysian financial institutions

The purpose of this study is to identify the determinants of dividend policy in Malaysian financial institutions. Panel data set were constructed from 33 financial institutions in Malaysia for a period of 10 years (2001-2010). The results show a statistically significant positive relationship between dividend policy and profitability, which implies that Malaysian financial institutions distribute higher dividends when they record higher profitability. Lagged dividend also shows a positive significant relationship with dividend policy, which implies that financial institutions in Malaysia follow a stable dividend policy that maintains regularity of dividend payments with gradual adjustments of dividend payments towards the target payout. On the other hand, leverage shows a significant negative relationship with dividend policy, which means that a riskier financial institution pays out lower dividends. In conclusion, profitability, lagged dividend and leverage are found to be the major determinants of dividend policy in relation to Malaysian financial institutions. The results support the agency cost theory, signaling theory and the free cash flow hypothesis

Advanced plasmonic interfaces for optimized light trapping in photovoltaics

Plasmonic interfaces are integrated to photovoltaic devices to enhance light trapping and improve efficiency. The optimum thickness of the spacer layer used to passivate the absorber layer and adjust its distance from the metal nanoparticles remains unclear. We integrate plasmonic interfaces consisting of Ag nanoparticles and silicon nitride spacers of different thicknesses to the back of a-Si:H absorber to investigate the optimum thickness of the spacer layer and use the photocurrent in a-Si:H to indicate the enhancement in light-trapping. For integration to the back or front of the device, the localized surface plasmon resonance (LSPR) is shifted and broadened into the red with increased spacer layer thickness and the effect is more pronounced for integration to the back. An appreciable enhancement of photocurrent in a-Si:H is consistent with this broadening of LSPR and has a critical dependence on spacer layer thickness

The Extended Log-Logistic Distribution: Properties, Inference, and Applications in Medicine and Geology

In this paper, a new flexible extension of the log-logistic model called the extended odd Weibull log-logistic (EOWLL) distribution is studied. The EOWLL density can be expressed as a mixture of Dagum densities. The EOWLL distribution provides decreasing, increasing, upside-down bathtub, and reversed-J-shaped hazard rates, and right-skewed, symmetrical, and left-skewed densities. Its mathematical properties are derived. The EOWLL parameters are estimated via eight classical methods of estimation. Additionally, extensive simulations are obtained to explore the performance of the proposed methods for small and large samples. Two real-life sets of data from medicine and geology are analyzed, showing the flexibility of the EOWLL distribution as compared to other log-logistic extensions. The results show that the EOWLL distribution is more appropriate as compared to the Kumaraswamy transmuted log-logistic, alpha-power transformed log-logistic, and additive Weibull log-logistic distributions, among others

Decay resistance of acetic, propionic and butyric anhydrides modified rubberwood against white rot (Trametes versicolor)

The effectiveness of rubberwood modified with acetic, propionic and butyric anhydrides against white rot Trametes versicolor was investigated. Specimens measuring 5 mm × 20 mm × 20 mm (l × w × t) underwent a Soxhlet extraction with toluene/methanol/acetone (4:1:1 by volume) for 8 h, and then oven-dried at 103 °C for 24 h. The specimens were vacuum-impregnated with anhydrides for durations ranging from 0.25 to 24 h at 120 °C. The weight percent gain (WPG) was calculated and the chemical bonding was analysed with Fourier transform infra-red (FTIR). The specimens were leached in deionised water according to EN 84 (1997) and exposed to white rot in an incubation room at 22 °C for 16 weeks. The study found that the acetic, propionic and butyric anhydrides reduced the rate of decay but did not totally protect rubberwood from T. versicolor. All the modified rubberwoods were classified as durability class 1 comparable to Scots pine and European beech. The final moisture content had a positive correlation with weight loss following decay. Scanning electron microscopy showed that hyphae penetrated cells in both untreated and modified rubberwood

Smartphone-based Wireless Operated Milliliter-scale Bioreactor

This paper presents the development of a smartphone-based wireless operated milliliter scale bioreactor. The bioreactor has a working volume of 18 mL and is made of poly (methylmethacrylate) (PMMA) and poly (dimethylsiloxane) (PDMS) polymers using a laser engraving methodology. Temperature and reactor stirring speed are the controlled variables and wireless communication is achieved through a wireless transceiver embedded in a low-cost controller platform. The results attained are very promising as the controller is able to control the desired reactor variables precisely through wireless communications

Accuracy and quickness criterion-based driving skill metric for human adaptive mechatronics system

Previous studies on driving skill algorithm have combined tracking error and time related variables into algorithm formulation. This method however does not include a car orientation and lateral speed information as an integral part of the algorithm. Two new variables are introduced into the algorithm structure, namely, orientation angle and lateral speed. Nine participants were carefully recruited for a driving test to validate the algorithm. A simulated driving environment was specifically devised for this experiment. A driving track used in this experiment was segmented into five different severities for data analysis. Two fundamental goals have led to the collection and subsequent analysis of the data. The first is analysing the variables in relation to the driving task. The second involves data analysis being further extended into analysing the algorithm performance over estimating the driving skill index. The results reveal that the proposed variables are well correlated with the driving task, and improvement in algorithm performance is found to be almost double compared to the previous algorithm

Exploring university students’ nutrition literacy in Saudi Arabia: a cross-sectional survey

IntroductionImproving individuals’ nutrition literacy can be one way to promote healthy dietary behaviors, which lowers the incidence of non-communicable diseases. In Saudi Arabia, there is a limited information regarding nutrition literacy among students. Therefore, the purposes of this study was to investigate university students’ nutrition literacy and identify its predictors in Saudi Arabia. Another objective was to assess how nutrition literacy is associated with eating habits among this sample.MethodsThis cross-sectional study was carried out among students attending the University of Jeddah and King Abdulaziz University (Jeddah City) in Saudi Arabia from June 2023 to September 2023. Using a convenience sampling approach, 570 students were enrolled in this study. An online-based structured survey tool including demographic details, a food frequency questionnaire, and a nutrition literacy scale was used to collect the data. Descriptive and multiple binary logistic regression analysis were performed.ResultsApproximately 40.4% of the participants exhibited poor nutrition literacy. Female students were less likely than male students to have poor nutrition literacy (adjusted odds ratio, AOR = 0.62; 95% confidence interval, CI = 0.42, 0.92). Underweight (AOR = 1.73; 95%CI = 1.22, 4.56) and overweight participants (AOR = 3.1; 95%CI = 2.77, 7.23) were at higher risk of having poor level of nutrition literacy as compared to those who had normal weight. Students who did not take any nutrition-related courses had a 1.3 times higher probability of having a poor level of nutrition literacy compared to their counterparts (AOR = 1.3; 95%CI = 1.05, 3.74). Moreover, poor nutrition literacy was associated with higher weekly consumption frequencies of red meat, processed foods, funk foods and sugar-sweetened beverages.ConclusionA higher percentage of university students had poor nutrition literacy, which was associated with gender, self-reported BMI status, nutrition-related courses and unhealthy eating habits. These findings can assist university administrators and policymakers in implementing effective measures to enhance students’ nutrition literacy rates in Saudi Arabia

Distributed t-way test suite execution with code coverage on multiple machines

This paper present a distributed test suite execution in term of code coverage analysis for testing a t-way test suite data using tuple space technology with Map and Reduce mechanism. The generated t-way test suite data and software under test (SUT) source code are preloaded into their respective partition using hash based routing algorithm. Each partition parsed each test case within the test suite into actual test data file. The code coverage of SUT source code is tested with each test case in actual test data and produces a test coverage result at their respective partition in term of class, method, block and line coverage. A case study of CGPA calculator as SUT is done to measure the test suite execution performance in term of test coverage with varying interaction strength on single and multiple machine environments. The scalability analysis of distributed test suite execution is also done in term of speedup gained while running on a multiple machine environments. An encouraging result is obtained on test coverage and speedup for multiple machine environments as compared to single machine environment. Higher test coverage and more speedup is obtained in higher machine environments

The elastic properties of unidirectional bamboo fibre reinforced epoxy composites

Natural fibres such as kenaf, jute, bamboo, flax and wood have been the subject of intensive researches in the area of fibre reinforced composite due to their environmental advantages of being renewable, biodegradable and sustainable. Bamboo fibre can be a good choice of natural fibre reinforcement for structural applications due to its excellent strength to weight ratio that is comparable to that of mild steel. In this study, mechanical properties of both continuous and short bamboo fibre reinforced composites are predicted using micromechanical approaches. The finite element method was used where three-dimensional micromechanical representative volume element with square and hexagonal packing geometry was implemented. The results were then compared with the findings from analytical approach that includes the rule of mixture and the Halpin-Tsai model. It was found that for all properties, the FEM and analytical methods give comparable trends of property on volume fraction plots. Furthermore, the longitudinal modulus given by all models are in excellent agreement as it increases linearly with the increase in bamboo fibre volume fraction