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Design Considerations for Long Travel Z-Axis Ultra-Precision Positioning Stage
Tarek Mohammad,Shaun Salisbury 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
Considering the recent technological advances in precision engineering and the concurrent progresses in biomedical research including numerous surgical operations, the development of precision positioning systems capable of executing large travel in vertical direction with nanometer scale resolution or simply Z nano-positioner has become inevitable. The motion in Z-axis is typically achieved by mounting a planner stage on an L-bracket which often has low force capacity and lacks compactness. In many applications, compactness is desired, yet long travel ranges are highly demanded. The actuator must provide enough output force to lift a mass mounted on it along with positioning platform weight against the effect of gravity. Therefore, design criteria and features for a novel compact positioner capable of lifting mass with long stroke and nanometer accuracy have been presented and discussed. In the designs, two major challenges have been faced and solved: proper installation of the actuator within the stage and perfect alignment of the actuator to the stage. An embedded actuator can provide the benefits to the structure of being realistically compact and the friction surfaces not being exposed to dust or any other contamination.
Client Communication: A Major Issue in Agile Development
Tarek El-Najar,Imtiaz Ahmad,Mohammad Alkandari 보안공학연구지원센터 2016 International Journal of Software Engineering and Vol.10 No.12
Agile development model solved a lot of its predecessor the waterfall model problems like time, cost, resources and high risk of failure due to incomplete or inaccurate requirements. However, agile model introduced the client communication problem; due to the structure and nature of agile methodologies, it depends heavily on communicating with client. With four layers of communication that get repeated in almost every agile iteration, failing to handle client communication is one of the main reasons behind failure of agile based projects. In this paper, we survey the existing methods of communication which are classified into two main categories: physical meetings/workshops and software communication tools. Each category is assessed and compared based on certain attributes such as availability, productivity, cost, reliability, trust and project coverage. In addition, the available solutions to address the communication problem, which include enhanced physical meetings/workshops and software tools like requirement engineering tools, agile management tools and social media sites and applications, are analyzed and assessed based on attributes such as usability, formality and project coverage. The study revealed that the available solutions did not address all the aspects of the communication problem. Therefore, it is desirable to develop an integrated solution which utilized communication software tool using social media frameworks as its backbone and physical meetings to benefit from human interaction and relationships to solve the communication problem in agile environment.
Leisure Time Physical Activity in Saudi Arabia: Prevalence, Pattern and Determining Factors
Amin, Tarek Tawfik,Al Khoudair, Ali Salah,Al Harbi, Mohammad Abdulwahab,Al Ali, Ahmed Radi Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.1
Background: Identification of reliable predictors of leisure time physical activity (LTPA) will enable healthcare providers to intervene and change the patterns of LTPA in the population to improve community health. Objectives: The objectives of this study were to determine prevalence and pattern of LTPA among adult Saudis aged 18-65 years, and to define the socio-demographic determinants that correlate with LTPA in Al-Hassa, Saudi Arabia. Subjects and Methods: A cross-sectional study of 2176 adult Saudis attending urban and rural primary health care centers were selected using a multistage proportionate sampling method. Participants were personally interviewed to gather information regarding socio-demographics, physical activity pattern using the Global Physical Activity Questionnaire (GPAQ). Physical activity (PA) in each domain was expressed in metabolic equivalents (METs). Results: The median total METs minutes/week for LTPA for both genders was 256, higher for men (636 METs minutes/week) compared to women (249METs minutes/week). Overall, only 19.8% of the total PA was derived from LTPA. Of the sampled population 50.0% reported doing no leisure activity. Using the cut off of 600 METs-minutes/day or 150 minutes of moderate intensity over 5 or more days/week, only 21.0% of the included sample were considered as being sufficiently active and 10.4% were in the high active category with beneficial health effects. Multivariate regression analysis showed that male, younger age (<35 years), absence of chronic disease conditions and moderate level of total PA were significant predictors for being active in the LTPA domain. Conclusion: The prevalence and intensity of LTPA among the included sample demonstrated low levels. Nearly 80% of the included sample population did not achieve the recommended LTPA level with beneficial health effects. Female gender, urban residence and associated chronic diseases correlated with a low LTPA.
Maha Raafat Abd El Fadeel,Ashraf Taha El-Dakhly,Ahmad Mohammad Allam,Tarek Korany Farag,Alaa Abdel-Moneim El-kholy 대한백신학회 2020 Clinical and Experimental Vaccine Research Vol.9 No.2
Purpose: Bovine respiratory disease is a worldwide health concern in the feedlot cattle causing morbidity and mortality in young with major economic losses to the producer. Programs of vaccination are integral parts of preventive health programs. We aim to prepare and evaluate lyophilized combined inactivated viruses (bovine viral diarrhea virus [BVDV] genotypes 1 and 2, bovine herpes virus type 1.1 [BoHV-1.1], bovine parainfluenza-3 virus [BPI-3V], and bovine respiratory syncytial virus [BRSV]) vaccine using saponin as a solvent and adjuvant in cattle. Materials and Methods: Lyophilized Pneumo-5 vaccine was formulated to include the inactivated BVDV genotypes 1 and 2, BoHV-1.1, BPI-3V, and BRSV. The saponin solution was used as an adjuvant and solvent. The prepared vaccines were adjusted to contain 1- and 1.5-mg saponin/dose. It was evaluated for its sterility, safety, and potency in mice and calves. The antibody titers in vaccinated calves were measured by virus neutralization test and enzyme-linked immunosorbent assay (ELISA). Results: The Pneumo-5 vaccine was found to be free from any contaminants and safe in mice. Meanwhile, the vaccine showed safety in calves which inoculated intramuscularly with the double dose of the vaccines. The overall immune response reached its peak in the 2nd-month post-vaccination. The vaccine contained saponin 1.5 mg/dose reached its antibodies peak in the 4th-week post-vaccination. All groups of vaccinated calves with both concentrations of the saponin did not show statistical significance in antibody titers measured by serum neutralization test and/or ELISA. Conclusion: The prepared vaccine, namely Pneumo-5, and adjuvanted with either 1 or 1.5 mg/dose saponin was proved safe and potent for effectual protection of calves against BVDV genotypes 1 and 2, BoHV-1.1, BPI-3V, and BRSV.
( Safaa A. S. Al-qaysi ),( Halah Al-haideri ),( Sana M. Al-shimmary ),( Jasim M. Abdulhameed ),( Othman I. Alajrawy ),( Mohammad M. Al-halbosiy ),( Tarek A. A. Moussa ),( Mohamed G. Farahat ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.5
Levan is an industrially important, functional biopolymer with considerable applications in the food and pharmaceutical fields owing to its safety and biocompatibility. Here, levan-type exopolysaccharide produced by Pantoea agglomerans ZMR7 was purified by cold ethanol precipitation and characterized using TLC, FTIR, <sup>1</sup>H, and <sup>13</sup>C NMR spectroscopy. The maximum production of levan (28.4 g/l) was achieved when sucrose and ammonium chloride were used as carbon and nitrogen sources, respectively, at 35°C and an initial pH of 8.0. Some biomedical applications of levan like antitumor, antiparasitic, and antioxidant activities were investigated in vitro. The results revealed the ability of levan at different concentrations to decrease the viability of rhabdomyosarcoma and breast cancer cells compared with untreated cancer cells. Levan appeared also to have high antiparasitic activity against the promastigote of Leishmania tropica. Furthermore, levan had strong DPPH radical scavenging (antioxidant) activity. These findings suggest that levan produced by P. agglomerans ZMR7 can serve as a natural biopolymer candidate for the pharmaceutical and medical fields.