Browsing by Author "Endris Mohammed"

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    Electrical Properties of two Hours Treated 4T1 Breast Cancer Cells and Effect of Magnetic Beads on Ionization of BT20 Breast Cancer Cells Using Optical Twezeers
    (Addis Ababa University, 2024-09) Guta Korsa; Endris Mohammed
    Study was undertaken to introduce the novel optical tweezers method for exploring the electrical charge developed and trap coefficient of pre-ionized 2 hour treated 4T1 breast cancer cells and to assess how magnetic beads affect the ionization properties of BT20 breast cancer cells. Specifically, the research focused on 4T1 breast cancer cells, which had been treated with the chemotherapy drug DMDD extracted from Averrhoa carambola L., and BT20 breast cancer cells mixed with 3.1 μm diameter polymer-coated magnetic beads. The trapping was achieved using an infrared diode-pumped Nd:YVO4 laser with a wavelength of 1064 nm, maximum output power of 8W, beam diameter of 4 mm, and a highly focused, linearly polarized beam. In experiments with the pre-ionized 2 hour treated 4T1 breast cancer cells, we recorded the following average values; the charge generated on cells in Z-numbers of 432.60±688.77, angular frequency of 72.12±30.12 rad ⁄s and trap coefficient of 8.32±4.55 un/m. As the cells approached to the center of the trap, their motion was influenced by the opposing of the drag force and the electrostatic force generated by the induced electric field, that resulted in their deceleration. When magnetic beads inserted in BT20 breast cancer cells they affected their ionization characteristics as the cells stayed in the trap.
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    Teachers , Motivation and Job Satisfaction in Secondary Schools of Assosa Zone, Benishangul Gumuz Regional State
    (Addis Ababa University, 2017-09) Endris Mohammed
    Motivation is one of the most important tools of human resource management. Organizations design motivation systems to encourage employees to perform in the most effective way but also to attract potential candidates. The key to create the efficient motivation system is an answer to the question what really motivate employees. The main objective of this study is to assess the teachers work motivation and job satisfaction to identify the variables which are the most predictor of teachers’ work motivation and satisfaction in secondary schools of Assosa Zone. To accomplish this purpose, the study employed a descriptive survey research design. The study was carried out in randomly selected nine secondary schools of Assosa Zone. A total of 166 individuals participated in the study. Among them, 149 teachers were included as samples through random sampling technique. Additionally, 9 secondary school principals, 4 cluster supervisors and 4 Woreda education office coordinators were included through available sampling technique. Questionnaire and interview were the main instruments of data collection. The analysis of the quantitative data was carried out by using mean and standard deviations. The findings revealed that the school practices on the independent variables that influence teachers’ work motivation and job satisfaction are insufficient as most of the practices on independent variables scored below two, when it serves as the average of the likert scales. As a result teachers are not encouraged to disseminate their knowledge to students through effective teaching-learning method, to achieve schools objective as well as to stay in the profession. Due to this teachers are not successful to improve the students’ academic achievement as well as school goals. In general, the findings revealed that, secondary schools in Assosa Zone had not worked effectively on improving the motivation level of teachers and their job satisfaction which forced teachers to leave the profession. Based on the findings, it is recommended that secondary schools, Woreda and Zone education offices need to give necessary rewards, recognition, empower teachers , professional development, strength staff relationship and furnishing the working conditions with refreshment facilities