Search results for: Adel Omar Ashour

Authors: Omar bin Mihat

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The number of sudden deaths is increasing over the past years. These deaths occur not during physical activities but upon cessation. Post-mortem confirms these deaths as cardiac arrest non-specifically. Congenital heart disease is a condition undiagnosed whereby only surface upon physical exertion leading to sudden death is unavoidable. Channelopathy, a condition that refers to any disease from the defect in iron-channel function, particularly the sodium-potassium pump, during the cessation of the exercise can be controlled. The derivation of heart rate return (HRrtn) is a procedure of a control cooling down process according to the heart rate (HR). Empirically, potassium rises linearly with intensity and falls sharply upon abrupt cessation of exertion, resulting in fatal arrhythmia due to hypokalaemia. It is vital that the flux of potassium should be maintained within the normal range during physical activities. To achieve this, the dosage of physical exertion (exercise) should be identified. Various percentages of the intensity of maximum heart rate (MHR) will precipitate different adaptations and remodeling of various organs. 70% of MHR will surface physiological adaptations, including enhancement of endurance, fitness level, and general health, and there was no significant rise of serum potassium (K+) during the entire phase of the treadmill brisk walk at a different rate of perceived exertion (RPE) from the subject of various fitness background. There was also no significant rise in blood pressure (BP) during the entire phase of the treadmill brisk walk, substantiating 70% MHR is the safe dosage across different parameters of health and fitness level.

Keywords: potassium, maximal heart rate, exercise dosage, fitness level

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Authors: Adel Salem Bahakeem, Ahmad Jamal, Mir Md. Maruf Morshed, Elwaleed Awad Khidir

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Direct Current (DC) servo motors, or simply DC motors, play an important role in many industrial applications such as manufacturing of plastics, precise positioning of the equipment, and operating computer-controlled systems where speed of feed control, maintaining the position, and ensuring to have a constantly desired output is very critical. These parameters can be controlled with the help of control systems such as the Proportional Integral Derivative (PID) controller. The aim of the current work is to investigate the effects of Proportional (P) and Integral (I) controllers on the steady state and transient response of the DC motor. The controller gains are varied to observe their effects on the error, damping, and stability of the steady and transient motor response. The current investigation is conducted experimentally on a servo trainer CE 110 using analog PI controller CE 120 and theoretically using Simulink in MATLAB. Both experimental and theoretical work involves varying integral controller gain to obtain the response to a steady-state input, varying, individually, the proportional and integral controller gains to obtain the response to a step input function at a certain frequency, and theoretically obtaining the proportional and integral controller gains for desired values of damping ratio and response frequency. Results reveal that a proportional controller helps reduce the steady-state and transient error between the input signal and output response and makes the system more stable. In addition, it also speeds up the response of the system. On the other hand, the integral controller eliminates the error but tends to make the system unstable with induced oscillations and slow response to eliminate the error. From the current work, it is desired to achieve a stable response of the servo motor in terms of its angular velocity subjected to steady-state and transient input signals by utilizing the strengths of both P and I controllers.

Keywords: DC servo motor, proportional controller, integral controller, controller gain optimization, Simulink

Procedia PDF Downloads 87

Authors: Adel Alblihy, Reem Ali, Mashael Algethami, Ahmed Shoqafi, Michael S. Toss, Juliette Brownlie, Natalie J. Tatum, Ian Hickson, Paloma Ordonez Moran, Anna Grabowska, Jennie N. Jeyapalan, Nigel P. Mongan, Emad A. Rakha, Srinivasan Madhusudan

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Platinum resistance is a clinical challenge in ovarian cancer. Platinating agents induce DNA damage which activate Mre11 nuclease directed DNA damage signalling and response (DDR). Upregulation of DDR may promote chemotherapy resistance. Here we have comprehensively evaluated Mre11 in epithelial ovarian cancers. In clinical cohort that received platinum- based chemotherapy (n=331), Mre11 protein overexpression was associated with aggressive phenotype and poor progression free survival (PFS) (p=0.002). In the ovarian cancer genome atlas (TCGA) cohort (n=498), Mre11 gene amplification was observed in a subset of serous tumours (5%) which correlated highly with Mre11 mRNA levels (p<0.0001). Altered Mre11 levels was linked with genome wide alterations that can influence platinum sensitivity. At the transcriptomic level (n=1259), Mre11 overexpression was associated with poor PFS (p=0.003). ROC analysis showed an area under the curve (AUC) of 0.642 for response to platinum-based chemotherapy. Pre-clinically, Mre11 depletion by gene knock down or blockade by small molecule inhibitor (Mirin) reversed platinum resistance in ovarian cancer cells and in 3D spheroid models. Importantly, Mre11 inhibition was synthetically lethal in platinum sensitive XRCC1 deficient ovarian cancer cells and 3D-spheroids. Selective cytotoxicity was associated with DNA double strand break (DSB) accumulation, S-phase cell cycle arrest and increased apoptosis. We conclude that pharmaceutical development of Mre11 inhibitors is a viable clinical strategy for platinum sensitization and synthetic lethality in ovarian cancer.

Keywords: MRE11; XRCC1, ovarian cancer, platinum sensitization, synthetic lethality

Procedia PDF Downloads 104

Authors: Nor Azlina Ab.Rahman, Salwana Hassan, Zuraeda Ibrahim, Normah Omar, Jamaliah Said

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Revolution in the business environment has crucial growing changes on most globalized markets. Numerous of organizations are necessitating towards producing more proactive entrepreneurs with a dynamic teams, who can run and steer their business to victory. Revolutionizing on business strategy and entrepreneurial skills, also implementing innovation and practices to enhance its performance is necessary for these organizations to be more cost-efficient and increase their efficiency. The study aims to clarify issues of whether measurement has a positive effect on different aspects of innovation and best practices. The study contributes to the current understanding in three ways; first by presenting the important aspects of organizational innovation and best practices. Second by showing the importance of measurement in promoting different aspects of innovation and best practices. Third is to examine the link between innovation, best practices and sustainability in microfinance. The study has been executed by conducting a qualitative study toward the microfinance industry. A representative of management and employees in each company was selected through an invitation to participate in getting information for data collection purpose in the study. The study contains a comprehensive description of the impacts of measurement on different aspects of innovation and best practices towards sustainability in both microfinance industries and SMEs. Findings from this study shows that performance measurement has positive effects on issues related to innovation and best practices. The measurement for several aspects of innovation and best practices is good potential in microfinance industries. Additionally, measurement on innovation and best practices shows a positively related with each other to enhance organization performance. The study suggests that both academics and practitioners should focus on the development of new methods and practices to describe and scrutinize further understanding for measuring issues which is related to innovation and best practices, in order to better develop innovation and best practices towards sustainability. This effort would not only contribute to firm’s success, but also toward the development of the nation in the developing countries.

Keywords: best practices, innovation, microfinance, sustainability

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Authors: Raghad Alhusari, Farag Omar, Moustafa Fadel

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A traditional greenhouse is a metal frame agricultural building used for cultivation plants in a controlled environment isolated from external climatic changes. Using greenhouses in agriculture is an efficient way to reduce the water consumption, where agriculture field is considered the biggest water consumer world widely. Controlling greenhouse environment yields better productivity of plants but demands an increase of electric power. Although various control approaches have been used towards greenhouse automation, most of them are applied to traditional greenhouses with ventilation fans and/or evaporation cooling system. Such approaches are still demanding high energy and water consumption. The aim of this research is to develop a fuzzy control system that minimizes water and energy consumption by utilizing outside weather conditions and underground heat exchanger to maintain the optimum climate of the greenhouse. The proposed control system is implemented on an experimental model of thermally isolated greenhouse structure with dimensions of 6x5x2.8 meters. It uses fans for extracting heat from the ground heat exchanger system, motors for automatic open/close of the greenhouse windows and LED as lighting system. The controller is integrated also with environmental condition sensors. It was found that using the air-to-air horizontal ground heat exchanger with 90 mm diameter and 2 mm thickness placed 2.5 m below the ground surface results in decreasing the greenhouse temperature of 3.28 ˚C which saves around 3 kW of consumed energy. It also eliminated the water consumption needed in evaporation cooling systems which are traditionally used for cooling the greenhouse environment.

Keywords: automation, earth-to-air heat exchangers, fuzzy control, greenhouse, sustainable buildings

Procedia PDF Downloads 110

Authors: Omar Alsetoohy, Mohamed Ezzat, Mahmoud Abou Kamar

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The success of a restaurant or hotel depends very much on the quality and quantity of its human resources. Thus, establishing a competitive edge through human assets requires careful attention to the practices that best leverage these assets. Usually, hotel or restaurant employees recognize customer defection as an unfavorable or unpleasant occurrence associated with failure. These failures could be in handling, communication, learning, or encouragement. Besides, employees could be afraid of blame from their colleagues and managers, which prevents them from freely discussing these mistakes with them. Such behaviors, in turn, would push employees to withdraw from the workplace. However, we have a good knowledge of the leadership outcomes, but less is known about how and why these effects occur. Accordingly, mindful leaders usually analyze the causes and underlying mechanisms of failures for work improvement. However, despite the excessive literature in the field of leadership and employee behaviors, to date, no research studies had investigated the impact of a failure-tolerant restaurant culture on the employees’ withdrawal behaviors considering the moderating role of psychological empowerment and mindful leadership. Thus, this study seeks to investigate the impact of a failure-tolerant culture on the employees’ withdrawal behaviors in fast-food restaurants in Egypt considering the moderating effects of employee empowerment and mindful leaders. This study may contribute to the existing literature by filling the gap between failure-tolerant cultures and employee withdrawal behaviors in the hospitality literature. The study may also identify the best practices for restaurant operators and managers to deal with employees' failures as an improvement tool for their performance.

Keywords: failure-tolerant culture, employees’ withdrawal behaviors psychological empowerment, mindful leadership, restaurants

Procedia PDF Downloads 89

Authors: Omar Concepcion, Osvaldo De Melo, Arturo Escobosa

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Topological insulator (TI) materials are insulating in the bulk and conducting in the surface. The unique electronic properties associated with these surface states make them strong candidates for exploring innovative quantum phenomena and as practical applications for quantum computing, spintronic and nanodevices. Many materials, including Bi₂Te₃, have been proposed as TIs and, in some cases, it has been demonstrated experimentally by angle-resolved photoemission spectroscopy (ARPES), scanning tunneling spectroscopy (STM) and/or magnetotransport measurements. A clean surface is necessary in order to make any of this measurements. Several techniques have been used to produce films and different kinds of nanostructures. Growth and characterization in situ is usually the best option although cleaving the films can be an alternative to have a suitable surface. In the present work, we report a comparison of Bi₂Te₃ grown by physical vapor transport (PVT) and molecular beam epitaxy (MBE). The samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and ARPES. The Bi₂Te₃ samples grown by PVT, were cleaved in the ultra-high vacuum in order to obtain a surface free of contaminants. In both cases, the XRD shows a c-axis orientation and the pole diagrams proved the epitaxial relationship between film and substrate. The ARPES image shows the linear dispersion characteristic of the surface states of the TI materials. The samples grown by PVT, a relatively simple and cost-effective technique shows the same high quality and TI properties than the grown by MBE.

Keywords: Bismuth telluride, molecular beam epitaxy, physical vapor transport, topological insulator

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Authors: Adel Ahmed Aly Elhabab, Ibrahim Adsani

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The present study deals with detailed geochemical and mineralogical studies of the coastal plain sediments formed along the shoreline of the Arabian Gulf area, Kuwait. These deposits are mainly fluviomarine and beach sands. The coastal plain deposits of the central Kuwait shoreline zone were found to consist of average medium-grained sand. The sand composed, on average of about 90% sand, and about 10% or less is mud, and has a unimodal distribution with a mode of medium sand (1-2 ф). The sediments consist mainly quartz, Feldspar, clay minerals with carbonate minerals (detritus calcite and dolomite) and rock fragments (chert). The mineralogy of the clay fractions of the sediments is dominated by illite, palygorskite, mixed layer illite-montmorillonite with minor amounts of chlorite and Kaolinite Heavy minerals are concentrated in the very fine sand fraction and are dominated by opaque minerals, and non opaque minerals which represented by amphiboles, pyroxenes, epidotes, dolomite, zircon, tourmaline, rutile, garnet and other which represented by Staurolite, Kyanite, Andalusite and Sillimenite as a trace amounts. The chemical analysis for the detrital amphibole grains from sandstone of coastal plain sediments shows the following features; the grains which have (Na+K) <0.50 its composition ranges from actino hornblende to magnesio hornblende, but the grains which have (Na+K) >0.50 its composition have wide variation and on the (Na+K)-AlIV diagram can be characterized two association: Association 1 which characterized by low amount of AlIV and low amount of (Na+K), by comparing the chemical composition of this association and the chemical composition of amphibole grains from older basement rock, can be say, these association may be derived from metamorphic source rocks and association 2 which characterized by high amount of AlIV and low amount of (Na+K), may be derived from volcanic source rocks.

Keywords: chemical composition, clay minerals, coastal area, electro probe micro analyzer (EPMA), fluviomarine sediments, heavy minerals

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Authors: Omar Ali, Adesh Ramsubhag, Jayaraj Jayaraman

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Seaweed extracts have been reported as plant biostimulants which could be a safer, organic alternative to harsh pesticides. The incentive to use seaweed-based biostimulants is becoming paramount in sustainable agriculture. The current study, therefore, screened a commercial extract of A. nodosum in tomatoes, cultivated in Trinidad to showcase the multiple beneficial effects. Foliar treatment with an A. nodosum commercial extract led to significant increases in fruit yield and a significant reduction of incidence of bacterial spots and early blight diseases under both greenhouse and field conditions. Investigations were carried out to reveal the possible mechanisms of action of this biostimulant through defense enzyme assays and transcriptome profiling via RNA sequencing of tomato. Studies into disease control mechanisms by A. nodosum showed that the extract stimulated the activity of enzymes such as peroxidase, phenylalanine ammonia-lyase, chitinase, polyphenol oxidase, and β-1,3-glucanase. Additionally, the transcriptome survey revealed the upregulation and enrichment of genes responsible for the biosynthesis of growth hormones, defense enzymes, PR proteins and defense-related secondary metabolites, as well as genes involved in the nutrient mobilization, photosynthesis and primary and secondary metabolic pathways. The results of the transcriptome study also demonstrated the cross-talks between growth and defense responses, confirming the bioelicitor and biostimulant value of seaweed extracts in plants. These effects could potentially implicate the benefits of seaweed extract and validate its usage in sustainable crop production.

Keywords: A. nodosum, biostimulants, elicitor, enzymes, growth responses, seaweeds, tomato, transcriptome analysis

Procedia PDF Downloads 142

Authors: Omar Bouledroua, Djamel Zelmati, Zahreddine Hafsi, Milos B. Djukic

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Transporting hydrogen gas through the existing natural gas pipeline network offers an efficient solution for energy storage and conveyance. Hydrogen generated from excess renewable electricity can be conveyed through the API 5L steel-made pipelines that already exist. In recent years, there has been a growing demand for the transportation of hydrogen through existing gas pipelines. Therefore, numerical and experimental tests are required to verify and ensure the mechanical integrity of the API 5L steel pipelines that will be used for pressurized hydrogen transportation. Internal pressure loading is likely to accelerate hydrogen diffusion through the internal pipe wall and consequently accentuate the hydrogen embrittlement of steel pipelines. Furthermore, pre-cracked pipelines are susceptible to quick failure, mainly under a time-dependent cyclic pressure loading that drives fatigue crack propagation. Meanwhile, after several loading cycles, the initial cracks will propagate to a critical size. At this point, the remaining service life of the pipeline can be estimated, and inspection intervals can be determined. This paper focuses on the hydrogen embrittlement of API 5L steel-made pipeline under cyclic pressure loading. Pressurized hydrogen gas is transported through a network of pipelines where demands at consumption nodes vary periodically. The resulting pressure profile over time is considered a cyclic loading on the internal wall of a pre-cracked pipeline made of API 5L steel-grade material. Numerical modeling has allowed the prediction of fatigue crack evolution and estimation of the remaining service life of the pipeline. The developed methodology in this paper is based on the ASME B31.12 standard, which outlines the guidelines for hydrogen pipelines.

Keywords: hydrogen embrittlement, pipelines, transient flow, cyclic pressure, fatigue crack growth

Procedia PDF Downloads 65

Authors: Zoaib Mirza

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Half of the Muslim countries in the world have declared Islam the state religion in their constitutions. Yet, none of these countries have implemented authentic Islamic laws in line with the Quran (Holy Book), practices of Prophet Mohammad (P.B.U.H) called the Sunnah, and his four successors known as the Rightly Guided - Khalifa. Since their independence, these countries have adopted different government systems like Democracy, Dictatorship, Republic, Communism, and Monarchy. Instead of benefiting the people, these government systems have put these countries into political, social, and economic crises. These Islamic countries do not have equal representation and membership in worldwide political forums. Western countries lead these forums. Therefore, it is now imperative for the Muslim leaders of all these countries to collaborate, reset, and implement the original Islamic form of government, which led to the prosperity and success of people, including non-Muslims, 1400 years ago. They should unite as one nation under Khalifat, which means establishing the authority of Allah (SWT) and following the divine commandments related to the social, political, and economic systems. As they have declared Islam in their constitution, they should work together to apply the divine framework of the governance revealed by Allah (SWT) and implemented by Prophet Mohammad (P.B.U.H) and his four successors called Khalifas. This paper provides an overview of the downfall and the end of the Khalifat system by 1924, the ways in which the West caused political, social, and economic crises in the Muslim countries, and finally, a summary of the social, political, and economic systems implemented by the Prophet Mohammad (P.B.U.H) and his successors, Khalifas, called the Rightly Guided – Hazrat Abu Bakr (RA), Hazrat Omar (RA), Hazrat Usman (RA), and Hazrat Ali (RA).

Keywords: khalifat, khilafat-e-Rashida, the rightly guided, colonization, capitalism, neocolonization, government systems

Procedia PDF Downloads 96

Authors: Rofida Gamal, Mostafa Mohammed, Mariam Adel, Marwa Gamal, Marwa kamal, Ayat Saber, Maha Mamdouh, Amira Emad, Mai Ramadan

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Lynch Syndrome is an inherited genetic condition associated with an increased risk of colorectal and other cancers. Detecting Lynch Syndrome in individuals is crucial for early intervention and preventive measures. This study proposes a computational pipeline for Lynch Syndrome detection by integrating alignment, variant calling, and annotation. The pipeline leverages popular tools such as FastQC, Trimmomatic, BWA, bcftools, and ANNOVAR to process the input FASTQ file, perform quality trimming, align reads to the reference genome, call variants, and annotate them. It is believed that the computational pipeline was applied to a dataset of Lynch Syndrome cases, and its performance was evaluated. It is believed that the quality check step ensured the integrity of the sequencing data, while the trimming process is thought to have removed low-quality bases and adaptors. In the alignment step, it is believed that the reads were accurately mapped to the reference genome, and the subsequent variant calling step is believed to have identified potential genetic variants. The annotation step is believed to have provided functional insights into the detected variants, including their effects on known Lynch Syndrome-associated genes. The results obtained from the pipeline revealed Lynch Syndrome-related positions in the genome, providing valuable information for further investigation and clinical decision-making. The pipeline's effectiveness was demonstrated through its ability to streamline the analysis workflow and identify potential genetic markers associated with Lynch Syndrome. It is believed that the computational pipeline presents a comprehensive and efficient approach to Lynch Syndrome detection, contributing to early diagnosis and intervention. The modularity and flexibility of the pipeline are believed to enable customization and adaptation to various datasets and research settings. Further optimization and validation are believed to be necessary to enhance performance and applicability across diverse populations.

Keywords: Lynch Syndrome, computational pipeline, alignment, variant calling, annotation, genetic markers

Procedia PDF Downloads 51

Authors: F. Alaa Ali, S. A. Sherein Abdelgayed, S. Osama. EL-Tawil, M. Adel Bakeer

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Tartrazine is an organic azo dyes food additive widely used in foods, drugs, and cosmetics. The present study aimed to investigate the toxic effects of tartrazine on kidneys and liver biomarkers in addition to the investigation of oxidative stress and change of histopathological structure of liver and kidneys in 30 male rats. Tartrazine was orally administrated daily at dose 200 mg/ kg bw (1/ 10 LD₅₀) for sixty days. Serum and tissue samples were collected at the end of the experiment to investigate the underlying mechanism of tartrazine through assessment oxidative stress (Glutathione (GSH), Superoxide dismutase (SOD) and malondialdehyde (MDA) and biochemical markers (alanine aminotransferase (ALT), aspartate aminotransferase (AST), Total protein and Urea). Liver and kidneys tissue were collected and preserved in 10% formalin for histopathological examination. The obtained values were statistically analyzed by one way analysis of variance (ANOVA) followed by multiple comparison test. Biochemical analysis revealed that tartrazine induced significant increase in serum ALT, AST, total protein, urea level compared to control group. Tartrazine showed significant decrease in liver GSH and SOD where their values when compared to control group. Tartrazine induced increase in liver MDA compared to control group. Histopathology of the liver showed diffuse vacuolar degeneration in hepatic parenchyma, the portal area showed sever changes sever in hepatoportal blood vessels and in the bile ducts. The kidneys showed degenerated tubules at the cortex together with mononuclear leucocytes inflammatory cells infiltration. There is perivascular edema with inflammatory cell infiltration surrounding the congested and hyalinized vascular wall of blood vessel. The present study indicates that the subchronic effects of tartrazine have a toxic effect on the liver and kidneys together with induction of oxidative stress by formation of free radicals. Therefore, people should avoid the hazards of consuming tartrazine.

Keywords: albino rats, tartrazine, toxicity, pathology

Procedia PDF Downloads 335

Authors: Hager E. Amer, Hany El Saftawy, Laila Rashed, Ahmed M. Ata, Fatma Metwally, Hesham Mettawei, Hossam E. Sayed, Tamer Adel, Kareem M. El Sawah

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Aim: The purpose of this study is to regenerate the damaged photoreceptor cells as a result of argon laser as a model of Retinitis Pigmentosa in rabbits' retina by using adult stem cells from rabbits' bone marrow. Background: Retinitis pigmentosa (RP) is a group of inherited disorders that primarily affect photoreceptor and pigment epithelium function. RP leads to loss of the rod outer segment and shorten the photoreceptor layer and expose the photoreceptor cell body to high-pressure levels in oxygen (oxidative stress) leads to apoptosis to the rod and cone cells. In particular, there is no specific treatment for retinitis pigmentosa. Materials and Methods: Forty Two Giant (Rex) rabbits were used in this experiment divided into 3 groups: Group 1: Control (6 rabbits), Group 2: Argon laser radiated as a model of retinitis pigmentosa (12 rabbits), Group 3: Laser radiated and treated by 6 million stem cells (12 rabbits). The last two groups are divided each into two subgroups each subgroup contains 6 rabbits, the ophthalmological examination was performed on rabbits, blood samples and retina samples were taken after 25 days and after 36 days from the laser radiation (10 days and 21 days after stem cells insertion in group 3) to perform the biochemical analysis. Results: Compared to control Group, a decrease of ERG wave amplitude and antioxidant substances (Glutathione) in blood and retina in group 2, and an increase of oxidative stress substances (Nitric oxide, Malonaldehyde, and carponyl protein) and apoptotic substances (Advanced glycation end product and M-metalloproteinase) in blood and retina. Compared to group 2, mostly increases of antioxidant substances and ERG wave amplitude in group 3, and mostly decreases in oxidative stress substances and apoptotic substances. Conclusion: Insertion of 6 million stem cells intravitreous gives good results in regeneration of the damaged photoreceptor cells after 21 days.

Keywords: retinitis pigmentosa, stem cells, argon laser, oxidative stress, apoptosis

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Authors: Amany Haridy, Ahmed Elseragy, Fahd Omar

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The issue of temperature increase in the urban microclimate has been at the center of attention recently, especially in dense urban areas, such as the City of Alexandria in Egypt, where building surfaces have become the dominant element (more than green areas and streets). Temperatures have been rising during daytime as well as nighttime, however, the research focused on the rise of air temperature at night, a phenomenon known as the urban heat island. This phenomenon has many effects on ecological life, as well as human health. This study provided evidence of the possibility of reducing the urban heat island by using a green building envelope (green wall and green roof) in Alexandria, Egypt. This City has witnessed a boom in growth in its urban fabric and population. A simulation analysis using the Envi-met software to find the ratio of air temperature reduction was performed. The simulation depended on the orientation of the green areas and their density, which was defined through a process of climatic analysis made by the Diva plugin using the Grasshopper software. Results showed that the reduction in air temperature varies from 0.8–2.0 °C, increasing with the increasing density of green areas. Many systems of green wall and green roof can be found in the local market. However, treating an existing building requires a careful choice of system to fit the building construction load and the surrounding nature. Among the systems of choice, there was the ‘geometric system’ of vertical greening that can be fixed on a light aluminum structure for walls and the extensive green system for roofs. Finally, native plants were the best choice in the long term because they fare well in the local climate.

Keywords: envi-met, green building envelope, urban heat island, urban microclimate

Procedia PDF Downloads 179

Authors: Sarah El-Gamal, Passent Hossam, Ahmed Abd El Aziz, Rojina Mahmoud, Ahmed Hassan, Dalia Hilal, Eman Ayman, Hana Haytham, Omar Khamis

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Several concerns fall upon the supply chain, especially the cold supply chain. According to the literature, the main challenges in the cold supply chain are the distribution and storage phases. In this research, researchers focused on the storage area, which contains several activities such as the picking activity that faces a lot of obstacles and challenges The implementation of IoT solutions enables businesses to monitor the temperature of food items, which is perhaps the most critical parameter in cold chains. Therefore, researchers proposed a practical solution that would help in eliminating the problems related to ineffective picking for products, especially fish and seafood products, by using IoT technology, most notably LiFi technology. Thus, guaranteeing sufficient picking, reducing waste, and consequently lowering costs. A prototype was specially designed and examined. This research is a single case study research. Two methods of data collection were used; observation and semi-structured interviews. Semi-structured interviews were conducted with managers and decision maker at Carrefour Alexandria to validate the problem and the proposed practical solution using IoTandLiFi technology. A total of three interviews were conducted. As a result, a SWOT analysis was achieved in order to highlight all the strengths and weaknesses of using the recommended Lifi solution in the picking process. According to the investigations, it was found that the use of IoT and LiFi technology is cost effective, efficient, and reduces human errors, minimize the percentage of product waste and thus save money and cost. Thus, increasing customer satisfaction and profits gained.

Keywords: cold supply chain, picking process, temperature control, IOT, warehousing, LIFI

Procedia PDF Downloads 163

Authors: Quin Emparan, Razif Harun, Dayang R. A. Biak, Rozita Omar, Michael K. Danquah

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Cultivation of immobilized microalgae cells is on the rise for biotechnological applications. In this study, cultivation of Chlorella vulgaris was carried out in the form of suspended free-cell and immobilized cells system. NaCS-PDMDAAC capsules were used to immobilize C. vulgaris. Initially, the synthesized NaCS with C. vulgaris culture were prepared at various concentration of 5- 20% (w/v) using a 6% hardening solution (PDMDAAC) to investigate the capsules' gel stability and suitability for microalgae cells growth. Then, the capsules produced from 15% NaCS with C. vulgaris culture were furthered investigated using 5%, 10%, and 15% (w/v) of PDMDAAC solution. The capsules' gel stability was evaluated through dissolution time and loss of uniform spherical shape of capsules, while suitability for microalgae cells growth was evaluated through the optical density of microalgae. In this study, the 15% NaCS-10% PDMDAAC capsules were found to be the most suitable to sustain the capsules' gel stability and microalgae cells growth in MLA. For that reason, the C. vulgaris immobilized in the 15% NaCS-10% PDMDAAC capsules were further characterized using physicochemical analysis in terms of morphological, carbon (C), hydrogen (H) and nitrogen (N), Fourier transform-infrared (FT-IR), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), zeta potential and Brunauer-Emmet-Teller (BET) analyses. The results revealed that the presence of sulfonates in the synthesized NaCS and NaCS-PDMDAAC capsules without and with C. vulgaris proves that cellulose alcohol group was successfully bonded by sulfo group. Besides that, immobilized microalgae cells have a smaller cell size of 6.29 ± 1.09 µm and zeta potential of -11.93 ± 0.91 mV than suspended free-cells microalgae culture. It can be summarized that immobilization of C. vulgaris in the 15% NaCS-10% PDMDAAC capsules are relevant as a bioremediator for wastewater treatment purposes due to its suitable size of pore and capsules as well as structural and compositional properties.

Keywords: biological capsules, immobilized cultivation, microalgae, physico-chemical analysis

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Authors: Karem H. Alzoubi, Ahmad S. Alkofahi, Omar F. Khabour, Nizar M. Mhaidat

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Herbal medicinal products represent a major focus for drug development and industry and it holds a significant share in drug-market all over the globe. In here, selected medicinal plant extracts from Jordan with high antioxidative capacity were tested for their protective effect against oxidative DNA damage using in vitro 8-hydroxydeoxyguanisine and sister chromatid exchanges (SCEs) assays in cultured human lymphocytes. The following plant extracts were tested Cupressus sempervirens L., Psidium guajava (L.) Gaerth., Silybum marianum L., Malva sylvestris L., Varthemia iphionoides Boiss., Eminium spiculatum L. Blume, Pistachia palaestina Boiss., Artemisia herba-alba Asso, Ficus carica L., Morus alba Linn , Cucumis sativus L., Eucalyptus camaldulensis Dehnh., Salvia triloba L., Zizyphus spina-christi L. Desf., and Laurus nobilis L. A fractionation scheme for the active plant extracts of the above was followed. Plants extract fractions with best protective properties against DNA damage included hexane fraction of S. marianum L. (aerial parts), chloroform fractions of P. palaestina Boiss. (Fruits), ethanolic fractions of E. camaldulensis Dehnh (leaves), S. triloba L. (leaves), and ethanolic fractions of Z. spina-christi L. Desf. (Fruits/leaves). On the other hand, the ethanolic extracts of V. iphionoides Boiss was found to increase oxidative DNA damage. Results of the SCEs are undergoing. In conclusion, plant extracts with antioxidative DNA damage properties might have clinical applications in cancer prevention.

Keywords: medicinal plants extract, fractionation, oxidative DNA damage, 8-hydroxydeoxyguanisine, SCEs, Jordan

Procedia PDF Downloads 277

Authors: Salma A. El-Marasy, Reham M. Abd-Elsalam, Omar A. Ahmed-Farid

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Dementia is characterized by impairments in memory and other cognitive abilities. This study aims to elucidate the possible ameliorative effect of silymarin on scopolamine-induced dementia using the object recognition test (ORT). The study was extended to demonstrate the role of cholinergic activity, oxidative stress, neuroinflammation, brain neurotransmitters and histopathological changes in the anti-amnestic effect of silymarin in demented rats. Wistar rats were pretreated with silymarin (200, 400, 800 mg/kg) or donepezil (10 mg/kg) orally for 14 consecutive days. Dementia was induced after the last drug administration by a single intraperitoneal dose of scopolamine (16 mg/kg). Then behavioral, biochemical, histopathological, and immunohistochemical analyses were then performed. Rats pretreated with silymarin counteracted scopolamine-induced non-spatial working memory impairment in the ORT and decreased acetylcholinesterase (AChE) activity, reduced malondialdehyde (MDA), elevated reduced glutathione (GSH), restored gamma-aminobutyric acid (GABA) and dopamine (DA) contents in the cortical and hippocampal brain homogenates. Silymarin dose-dependently reversed scopolamine-induced histopathological changes. Immunohistochemical analysis showed that silymarin dose-dependently mitigated protein expression of a glial fibrillary acidic protein (GFAP) and nuclear factor kappa-B (NF-κB) in the brain cortex and hippocampus. All these effects of silymarin were similar to that of the standard anti-amnestic drug, donepezil. This study reveals that the ameliorative effect of silymarin on scopolamine-induced dementia in rats using the ORT maybe in part mediated by, enhancement of cholinergic activity, anti-oxidant and anti-inflammatory activities as well as mitigation in brain neurotransmitters and histopathological changes.

Keywords: dementia, donepezil, object recognition test, rats, silymarin, scopolamine

Procedia PDF Downloads 115

Authors: Hussam Ashwi, Magbool Oraiby, Ali Muyidi, Hamad Al-Oufi, Mohammed Al-Oufi, Adel Al-Juhani, Salman Al-Zemaa, Saeed Al-Shahrani, Amal Abuallah, Wedad Sherwani, Mohammed Alattas, Ibraheem Attafi

Abstract:

Ethanol must be accurately identified and quantified to establish their use and contribution in criminal cases and forensic medicine. In some situations, it may be necessary to reanalyze an old specimen; therefore, it is essential to comprehend the effect of storage conditions and how long the result of a reanalyzed specimen can be reliable and reproducible. Additionally, ethanol can be produced via multiple in vivo and in vitro processes, particularly in diabetic patients, and the results can be affected by storage conditions and time. In order to distinguish between in vivo and in vitro alcohol generation in diabetes patient urine samples, various factors should be considered. This study identifies and quantifies ethanol and EtG in diabetic patients' urine samples stored in two different settings over time. Ethanol levels were determined using gas chromatography-headspace (GC-HS), and ethyl glucuronide (EtG) levels were determined using the immunoassay (RANDOX) technique. Ten urine specimens were collected and placed in a standard container. Each specimen was separated into two containers. The specimens were divided into two groups: those kept at room temperature (25 °C) and those kept cold (2-8 °C). Ethanol and EtG levels were determined serially over a two-week period. Initial results showed that none of the specimens tested positive for ethanol or EtG. At room temperature (15-25 °C), 7 and 14 days after the sample was taken, the average concentration of ethanol increased from 1.7 mg/dL to 2 mg/dL, and the average concentration of EtG increased from 108 ng/mL to 186 ng/mL. At 2–8 °C, the average ethanol concentration was 0.4 and 0.5 mg/dL, and the average EtG concentration was 138 and 124 ng/mL seven and fourteen days after the sample was collected, respectively. When ethanol and EtG levels were determined 14 days post collection, they were considerably lower than when stored at room temperature. A considerable increase in EtG concentrations (14-day range 0–186 ng/mL) is produced during room-temperature storage, although negative initial results for all specimens. Because EtG might be produced after a sampling collection, it is not a reliable indicator of recent alcohol consumption. Given the possibility of misleading EtG results due to in vitro EtG production in the urine of diabetic patients.

Keywords: ethyl glucuronide, ethanol, forensic toxicology, diabetic

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Authors: Mohamed Korany, Azza Gazy, Essam Khamis, Marwa Adel, Miranda Fawzy

Abstract:

Background: Two new, simple and specific methods; First, a Zero-crossing first-derivative technique and second, a chemometric-assisted spectrophotometric artificial neural network (ANN) were developed and validated in accordance with ICH guidelines. Both methods were used for the simultaneous estimation of the two closely related antioxidant nutraceuticals ; Coenzyme Q10 (Q) ; also known as Ubidecarenone or Ubiquinone-10, and Vitamin E (E); alpha-tocopherol acetate, in their pharmaceutical binary mixture. Results: For first method: By applying the first derivative, both Q and E were alternatively determined; each at the zero-crossing of the other. The D1 amplitudes of Q and E, at 285 nm and 235 nm respectively, were recorded and correlated to their concentrations. The calibration curve is linear over the concentration range of 10-60 and 5.6-70 μg mL-1 for Q and E, respectively. For second method: ANN (as a multivariate calibration method) was developed and applied for the simultaneous determination of both analytes. A training set (or a concentration set) of 90 different synthetic mixtures containing Q and E, in wide concentration ranges between 0-100 µg/mL and 0-556 µg/mL respectively, were prepared in ethanol. The absorption spectra of the training sets were recorded in the spectral region of 230–300 nm. A Gradient Descend Back Propagation ANN chemometric calibration was computed by relating the concentration sets (x-block) to their corresponding absorption data (y-block). Another set of 45 synthetic mixtures of the two drugs, in defined range, was used to validate the proposed network. Neither chemical separation, preparation stage nor mathematical graphical treatment were required. Conclusions: The proposed methods were successfully applied for the assay of Q and E in laboratory prepared mixtures and combined pharmaceutical tablet with excellent recoveries. The ANN method was superior over the derivative technique as the former determined both drugs in the non-linear experimental conditions. It also offers rapidity, high accuracy, effort and money saving. Moreover, no need for an analyst for its application. Although the ANN technique needed a large training set, it is the method of choice in the routine analysis of Q and E tablet. No interference was observed from common pharmaceutical additives. The results of the two methods were compared together

Keywords: coenzyme Q10, vitamin E, chemometry, quantitative analysis, first derivative spectrophotometry, artificial neural network

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Authors: A. Aboubakr, E. Fehling, S. A. Mourad, M. Omar

Abstract:

Wind energy is one of the most effective renewable sources especially offshore wind energy although offshore wind technology is more costly to produce. It is well known that offshore wind energy can potentially be very cheap once infrastructure and researches improve. Laterally, the trend is to construct offshore wind energy to generate the electricity form wind. This leads to intensive research in order to improve the infrastructures. Offshore wind energy is the construction of wind farms in bodies of water to generate electricity from wind. The most important part in offshore wind turbine structure is the foundation and its connection with the wind tower. This is the main difference between onshore and offshore structures. Grouted connection between the foundation and the wind tower is the most important part of the building process when constructing wind offshore turbines. Most attention should be paid to the actual grout connection as this transfers the loads safely from tower to foundations and the soil also. In this paper, finite element analyses have been carried out for studying the behaviour of offshore grouted connection for wind turbine structures. ATENA program have been used for non-linear analysis simulation of the real structural behavior thus demonstrating the crushing, cracking, contact between the two materials and steel yielding. A calibration of the material used in the simulation has been carried out assuring an accurate model of the used material by ATENA program. This calibration was performed by comparing the results from the ATENA program with experimental results to validate the material properties used in ATENA program. Three simple patch test models with different properties have been performed. The research is concluded with a result that the calibration showing a good agreement between the ATENA program material behaviors and the experimental results.

Keywords: grouted connection, 3D modeling, finite element analysis, offshore wind energy turbines, stresses

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Authors: Amalia Ardeljan, Lexi Frankel, Divesh Manjani, Gabriela Santizo, Maximillian Guerra, Omar Rashid

Abstract:

Introduction: Cytomegalovirus (CMV) infection is a widespread infection affecting between 60-70% of people in industrialized countries. CMV has been previously correlated with a higher incidence of Hodgkin Lymphoma compared to noninfected persons. Research regarding prior CMV infection and subsequent lymphoma development is still controversial. With limited evidence, further research is needed in order to understand the relationship between previous CMV infection and subsequent lymphoma development. This study assessed the effect of CMV infection and the incidence of lymphoma afterward. Methods: A retrospective cohort study (2010-2019) was conducted through a Health Insurance Portability and Accountability Act (HIPAA) compliant national database and conducted using International Classification of Disease (ICD) 9th,10th codes, and Current Procedural Terminology (CPT) codes. These were used to identify lymphoma diagnosis in a previously CMV infected population. Patients were matched for age range and Charlson Comorbidity Index (CCI). A chi-squared test was used to assess statistical significance. Results: A total number of 14,303 patients was obtained in the CMV infected group as well as in the control population (matched by age range and CCI score). Subsequent lymphoma development was seen at a rate of 11.44% (1,637) in the CMV group and 5.74% (822) in the control group, respectively. The difference was statistically significant by p= 2.2x10-16, odds ratio = 2.696 (95% CI 2.483- 2.927). In an attempt to stratify the population by antiviral medication exposure, the outcomes were limited by the decreased number of members exposed to antiviral medication in the control population. Conclusion: This study shows a statistically significant correlation between prior CMV infection and an increased incidence of lymphoma afterward. Further exploration is needed to identify the potential carcinogenic mechanism of CMV and whether the results are attributed to a confounding bias.

Keywords: cytomegalovirus, lymphoma, cancer, microbiology

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Authors: Othmane Essahili, Mohamed Ilsouk, Carine Duhayon, Omar Moudam

Abstract:

Due to their excellent and promising properties, a great deal of attention has recently been devoted to luminescent materials, particularly those utilizing rare earth elements. These materials play an essential role in low-cost energy conversion technology applications, such as luminescent solar concentrators (LSCs). They also have potential applications in Agri-PV systems and smart building windows. Luminescent materials based on europium (III) complexes are known for their high luminescence efficiency, long fluorescence lifetimes, and sharp emission bands. However, they present certain drawbacks related to their limited absorption capacity due to the forbidden 4f-4f electronic transitions. To address these drawbacks, using β-diketonate ligands as sensitizers appears as a promising solution to enhance luminescence intensity through the antenna effect, where the ligand's excited energy is transferred to the europium ions. In this study, we synthesized β-diketonate-based europium complexes with phenanthroline derivatives, modified with various methyl groups, to examine their effects on the complexes' stability in poly(methyl methacrylate) (PMMA) films. Our findings reveal that these complexes exhibit remarkable red emission and high photoluminescence quantum yield. Stability tests under different conditions for 1200 hours showed that complexes with a higher number of methyl substitutions offer improved photoluminescent stability and resistance to degradation, particularly in outdoor settings. This research underscores the potential of chemically tuned phenanthroline ligands in developing stable, efficient luminescent materials for future optoelectronic devices, including efficient and durable LSCs.

Keywords: luminescent materials, photochemistry, luminescent solar concentrators, β-diketonate-based europium complexes

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Authors: Elsayed A. M. Shokr, A. Alhazemi, T. Naser, Talal A. Zuhair, Adel A. Zuhair, Ahmed N. Alshamary, Thamer A. Alanazi, Hosam A. Alanazi

Abstract:

The main threats to human health from heavy metals are associated with exposure to Pb, Cd, Cu, Mo, Zn, Ni, Mn Co and Cr. is mainly via intake of drinking water being the most important source in most populations. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years. Although several adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues, and is even increasing in some parts of the world, in particular in less developed countries, though emissions have declined in most developed countries over the last 100 years. A strong relationship between contaminated drinking water with heavy metals from some of the stations of water shopping in Hail, KSA and chronic diseases such as renal failure, liver cirrhosis, and chronic anemia has been identified in this study. These diseases are apparently related to contaminant drinking water with heavy metals such as Pb, Cd, Cu, Mo, Zn, Ni, Mn Co and Cr. Renal failure is related to contaminate drinking water with lead and cadmium, liver cirrhosis to copper and molybdenum, and chronic anemia to copper and cadmium. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage but possibly also bone effects and fractures. The general population is primarily exposed to mercury via drinking water being a major source of methyl mercury exposure, and dental amalgam. During the last century lead, cadmium, zinc, iron and arsenic is mainly via intake of drinking water being the most important source in most populations. Long-term exposure to lead, cadmium, zinc, iron and arsenic in drinking-water is mainly related to primarily in the form of kidney damage. Studies of these diseases suggest that abnormal incidence in specific areas is related to toxic materials in the groundwater and thereby led to the contamination of drinking water in these areas.

Keywords: heavy metals, liver functions, kidney functions and chronic renal failure, hail, renal, water

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Authors: Muhammad Akmal Putera, Noriyuki Yasufuku, Adel Alowaisy, Ahmad Rifai

Abstract:

Indonesia’s government has planned a project for a high-speed railway connecting the capital cities, Jakarta and Surabaya, about 700 km. Based on that location, it has been planning construction above the lowland soil region. The lowland soil region comprises cohesive soil with high water content and high compressibility index, which in fact, led to a settlement problem. Among the variety of railway track structures, the adoption of the ballastless track was used effectively to reduce the settlement; it provided a lightweight structure and minimized workspace. Contradictorily, deploying this thin layer structure above the lowland area was compensated with several problems, such as lack of bearing capacity and deflection behavior during traffic loading. It is necessary to combine with ground improvement to assure a settlement behavior on the clayey soil. Reflecting on the assurance of strength increment and working period, those were convinced by adopting methods such as cement-treated soil as the substructure of railway track. Particularly, evaluating mechanical properties in the field has been well known by using the plate load test and cone penetration test. However, observing an increment of mechanical properties has uncertainty, especially for evaluating cement-treated soil on the substructure. The current quality control of cement-treated soils was established by laboratory tests. Moreover, using small strain devices measurement in the laboratory can predict more reliable results that are identical to field measurement tests. Aims of this research are to show an intercorrelation of confining pressure with the initial condition of the Young modulus (E_o), Poisson ratio (υ_o) and Shear modulus (G_o) within small strain ranges. Furthermore, discrepancies between those parameters were also investigated. Based on the experimental result confirmed the intercorrelation between cement content and confining pressure with a power function. In addition, higher cement ratios have discrepancies, conversely with low mixing ratios.

Keywords: amount of cement, elastic zone, high-speed railway, lightweight structure

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Authors: Sonda Jallouli, Sameh Ghroubi, Salma Sakka, Abdelmoneem Yahia, Mohamed Habib Elleuch, Imen Ben Dhia, Chokri Mhiri, Omar Hammouda

Abstract:

The pathophysiology, prevalence, and progression of MS are gender dependent. Indeed, the inflammation is more pronounced in women, but the neurodegeneration is more important in men. In addition, women have more sleep disorders while men suffer more from cognitive decline. These non-physical disorders can negatively affect postural balance and fall risk. However, no study has examined the difference between men and women in those physical parameters in MS. Our objective was to determine the effect gender difference on postural balance and fall risk in MS persons. Methods: Eight men and twelve women with relapsing remitting-MS participated in this study. The assessment includes a posturographic examination to assess static (with eyes opened (EO) and eyes closed (EC)) and dynamic (with EO) postural balance. Unipedal balance and fall risk were assessed by a clinical unipedal balance test and the Four Square Step Test, respectively. Sleep quality was assessed using Spiegel's questionnaire, and cognitive assessment was performed using the Montreal Cognitive Assessment (MoCA) and the Simple Reaction Time Test. Results: Compared to men, women showed an increase in CdPVm in static bipedal condition with EC (p=0.037; d=0.71) and a decrease in MoCA scores (p=0.028; d=1.06). No gender differences were found in the other tests. Discussion: Static postural balance was more impaired in women compared to men. This result could be explained by the more pronounced cognitive decline observed in women compared to men. Indeed, cognitive disorders have been shown to be predictive factors of postural balance impairment. Conclusion: women were less stable than men in the static condition, possibly due to their lower cognitive performance. This gender difference could be taken into account by therapists in training programs.

Keywords: multiple sclerosis, bipedal postural balance, fall risk, sleep disturbance, cognitive deficiency

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Authors: Dzul Fahmi Md. Nordin, Rosmini Omar

Abstract:

This conceptual paper aims to explore the concept of National Talent Retention for a nation by extending the works on Talent Retention in organizations to the scope of nations. The objective of this paper is to explore the relationship of National Talent Retention as the dependent variable with the three explored value propositions namely Firm Value Proposition, Higher Education and Training Value Proposition and National Attractiveness Value Proposition as the independent variables. Life Satisfaction is introduced in this study as a moderating variable to explore possibilities of Life Satisfaction as a mediator for the relationship between National Value Proposition and National Talent Retention. Theories such as Migration, Value Propositions, Life Satisfaction, Human Resource Management and Resource Based View are referred to in order to understand and explore the concept of National Talent Retention. Malaysia is chosen as the background of this study since Malaysia represents a developing nation with progressive economic, education and national policy which presents an interesting background for this exploratory paper. Surprisingly, Malaysia is still facing the phenomenon of Brain Drain which if not handled properly will hinder its Vision 2020 to progress a fully developed nation by year 2020. Mixed methodology analysis is proposed in this paper to include both qualitative face-to-face interview as well as quantitative survey questionnaire to study on the value proposition factors explored. Target respondents are strictly confined to Malaysia’s local high skilled talents either residing in Malaysia or migrated abroad since this paper is mainly interested to study on the concept of National Talent Retention and how successful Malaysia is projecting its value propositions from the perception of high skilled talent Malaysians. It is hoped that this paper could contribute towards understanding National Talent Retention concept where, the model could be replicated to identify influential factors specific to other nations.

Keywords: national talent retention, national value proposition, life satisfaction, high skilled talents

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Authors: Makhlouf Mourad, Messabih Sidi Mohamed, Bouchher Omar, Houali Farida, Benrachedi Khaled

Abstract:

Mesoporous materials are very commonly used as adsorbent materials for removing phenolic compounds. However, the adsorption mechanism of these compounds is still poorly controlled. However, understanding the interactions mesoporous materials/adsorbed molecules is very important in order to optimize the processes of liquid phase adsorption. The difficulty of synthesis is to keep an orderly and cubic pore structure and achieve a homogeneous surface modification. The grafting of Si(CH₃)₃ was chosen, to transform hydrophilic surfaces hydrophobic surfaces. The aim of this work is to study the kinetics and thermodynamics of two volatile organic compounds VOC phenol (PhOH) and P hydroxy benzoic acid (4AHB) on a mesoporous material of type MCM-48 grafted with an organosilane of the Trimethylchlorosilane (TMCS) type, the material thus grafted or functionalized (hereinafter referred to as MCM-48-G). In a first step, the kinetic and thermodynamic study of the adsorption isotherms of each of the VOCs in mono-solution was carried out. In a second step, a similar study was carried out on a mixture of these two compounds. Kinetic models (pseudo-first order, pseudo-second order) were used to determine kinetic adsorption parameters. The thermodynamic parameters of the adsorption isotherms were determined by the adsorption models (Langmuir, Freundlich). The comparative study of adsorption of PhOH and 4AHB proved that MCM-48-G had a high adsorption capacity for PhOH and 4AHB; this may be related to the hydrophobicity created by the organic function of TMCS in MCM-48-G. The adsorption results for the two compounds using the Freundlich and Langmuir models show that the adsorption of 4AHB was higher than PhOH. The values ​​obtained by the adsorption thermodynamics show that the adsorption interactions for our sample with the phenol and 4AHB are of a physical nature. The adsorption of our VOCs on the MCM-48 (G) is a spontaneous and exothermic process.

Keywords: adsorption, kinetics, isotherm, mesoporous materials, Phenol, P-hydroxy benzoique acid

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Authors: Adel A. Ghobbar, Varun Raman

Abstract:

The Corrective maintenance of components and systems is a problem plaguing almost every industry in the world today. Train operators’ and the maintenance repair and overhaul subsidiary of the Dutch railway company is also facing this problem. A considerable portion of the maintenance activities carried out by the company are unscheduled. This, in turn, severely stresses and stretches the workforce and resources available. One possible solution is to have a robust preventive maintenance plan. The other possible solution is to plan maintenance based on real-time data obtained from sensor-based ‘Health and Usage Monitoring Systems.’ The former has been investigated in this paper. The preventive maintenance model developed for train operator will subsequently be extended, to tackle the unscheduled maintenance problem also affecting the aerospace industry. The extension of the model to the aerospace sector will be dealt with in the second part of the research, and it would, in turn, validate the soundness of the model developed. Thus, there are distinct areas that will be addressed in this paper, including the mathematical modelling of preventive maintenance and optimization based on cost and system availability. The results of this research will help an organization to choose the right maintenance strategy, allowing it to save considerable sums of money as opposed to overspending under the guise of maintaining high asset availability. The concept of delay time modelling was used to address the practical problem of unscheduled maintenance in this paper. The delay time modelling can be used to help with support planning for a given asset. The model was run using MATLAB, and the results are shown that the ideal inspection intervals computed using the extended from a minimal cost perspective were 29 days, and from a minimum downtime, perspective was 14 days. Risk matrix integration was constructed to represent the risk in terms of the probability of a fault leading to breakdown maintenance and its consequences in terms of maintenance cost. Thus, the choice of an optimal inspection interval of 29 days, resulted in a cost of approximately 50 Euros and the corresponding value of b(T) was 0.011. These values ensure that the risk associated with component X being maintained at an inspection interval of 29 days is more than acceptable. Thus, a switch in maintenance frequency from 90 days to 29 days would be optimal from the point of view of cost, downtime and risk.

Keywords: delay time modelling, unscheduled maintenance, reliability, maintainability, availability

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