SINET: Ethiopian Journal of Science

Levels of some trace heavy metals and fat content in commercially available milk brands in Addis Ababa, Ethiopia

2025-01-25T11:11:08+00:00

The present study analyzed six pasteurized milk brands for their trace heavy metal concentrations and fat contents. The concentrations of Zn, Cu, Cr, Cd, Pb, and Ni were determined by flame atomic absorption spectrometry. The acid digestion method was employed and its validity was checked by recovery test and a good percentage recovery was obtained. Zinc in the different milk brands studied was found to be 1.93 - 3.31 µg/g. The trace metals Cu, Cr, Cd, Pb, and Ni were too low to be detected in all the milk samples. A statistical analysis of variance (ANOVA) at 95% confidence level (p > 0.05) showed that there is no significant difference in the mean concentrations of zinc among the milk brands. The results were also compared with international maximum permissible limits and the concentrations were within the safe limits for human consumption. The fat content of each milk brand was determined and found to be 2.4 - 3.0%. ANOVA at 95% confidence level (p > 0.05) indicated that there is no significant difference observed in the mean fat content among all the milk brands. The fat contents determined were also comparable with the reported values in the literature.

Effects of thiourea concentrations on the structural, morphological and optical properties of lead sulphied thin films prepared by solution growth method

2025-01-25T11:31:05+00:00

Chemical bath deposition (CBD) route employed to deposit lead sulphied (PbS) thin films at a bath temperature of 60 ⁰C for 40 minutes. The influence of applying different amount of thiourea concentration on the optical, morphological, structural properties of the deposited PbS films were studied. The prepared thin films were uniform, smooth and well adherent. The synthesized films were preferentially orientation along the (111) plane with face centered cubic crystal structure. The XRD studies showed that the lattice strain and dislocation densities of the synthesized PbS films decreased with increasing thiourea concentrations. The surface morphology study confirmed that as the thiourea molar concentrations increased the grains became enhanced. The EDS maps of PbS thin films revealed that the Pb and S elements were homogenously distributed on the surface of the thin films. The FTIR analysis of PbS nanocrystals revealed the presence of Pb-S vibration of Pb-S bonds observed around 613 cm^-1. The optical band gap estimated from UV-Vis analyses was found in the range of 0.82 eV to 0.98 eV.

A Comparison of Training Method Effects on Strength and Power Development of Young Ethiopian Soccer Players

2025-01-31T12:49:31+00:00

ABSTRACT: This study aimed to assess the effects of three different training methods on the development of explosive power and strength of young Ethiopian soccer players: resistance training, plyometric training alone, and mixed training, combining both plyometric exercise and resistance training. Participants in the study were 36 male U20 soccer players enrolled in Bahir Dar University Sports Academy's youth soccer training program. The authors used a "randomized block design," with a player's playing position serving as the stratum, to assign research participants to one of the three training programs (12 players in each of the plyometric, resistance, and mixed groups). These trainings were carried out with each group in accordance with the suggested exercises and training program for about four weeks in succession. The pre-test result showed that the dependent variables did not significantly differ between the groups. A post hoc MANOVA was employed to assess group differences, and partial eta-squared (ηp2) was utilized to compute the effect sizes. The result showed that there were significant main effects of the training method on ballistic strength F(2, 33) = 5.13, p = .012, ηp2 = 0.24 and explosive power, F(2, 32) = 12.10, p< .001, ηp2 = 0.44, but not on static strength, with the study participants in the plyometric training performing significantly better than those in the other two groups. Thus, it was concluded that plyometric training is better than resistance training and mixed training, which combined resistance training and plyometric training.

Anti-inflammatory Activities of the Leaves Extracts and Compounds Isolated from Boscia coriacea Graells, Uvaria leptocladon Oliv and In vitro Antibacterial Activity Test of the Isolated Compounds

2025-01-25T12:33:22+00:00

Anti-inflammatory drugs that have been used for the treatment of diseases are associated with numerous adverse effects. Antibacterial drugs resistance has become one of the major challenges of controlling infectious diseases. Therefore, it is necessary to search for safe and effective anti-inflammatory and antibacterial drugs. The objective of this study was to evaluate anti-inflammatory activities of the leaves extracts and compounds isolated from Boscia coriacea Graells, Uvaria leptocladon Oliv and antibacterial effects of the isolated compounds. Fresh leaves of B. coriacea and U. leptocladon were collected in April 2021 from Alie and Konso, Southern Ethiopia. The powdered leaves of B. coriacea and U. leptocladon were extracted using 80% MeOH by maceration extraction method. Compound isolation was performed using column chromatography and structural elucidation of the isolated compounds was done using nuclear magnetic resonance spectrometry (¹H NMR and ¹³C NMR). Carrageenan induced paw-edema model, cotton pellet induced granuloma method and protein denaturation assay were used to test the anti-inflammatory activities of the leaves extracts of the plants. Agar well diffusion assay was used to evaluate antimicrobial activity of the compounds isolated from the leaves of B. coriacea and U. leptocladon. Analysis of the difference between antibacterial and anti-inflammatory activities of the different groups was performed using one-way analysis of variance with post hoc comparison (Tukey’s test). β-sitosterol and lucidine-type compounds were isolated from B. coriacea.1-tiacontanol, Beta-sitosterol, Beta-sitosterol glucoside, whereas alpha-humulene were isolated from U. leptocladon. All compounds except 1-tricontanol showed anti-inflammatory and antibacterial activities. The leaves extracts of B. coriacea and U. leptocladon contain compounds, which have potent anti-inflammatory and antibacterial activities. Further study is needed to elucidate the mechanisms underlying the anti-inflammatory and antibacterial actions of βeta-sitosterol, βeta-sitosterol glucoside, alpha-humulene and lucidine type compound.

The density estimates of carnivore and economic impacts of livestock predations in the rehabilitated Bilema Community Conservation Area, East Gojam Zone, Ethiopia

2025-01-25T12:58:24+00:00

Bilema Community Conserved Area (BCCA) has been under rehabilitation for the last three decades by the surrounding community, and carnivores could reoccupy it. Thus, this study aimed to assess the density estimate of carnivores and their livestock predation in and around BCCA. The call-up method was applied to estimate carnivore densities, and questionnaire surveys were conducted to estimate livestock predation in three villages surrounding BCCA. Spotted hyenas (Crocuta Crocuta) and black-backed jackals (Lupulella mesomelas) are livestock predators in BCCA. A density of 1.6 spotted hyenas and 0.36 black-backed jackals were recorded per one ha. Spotted hyenas attacked cattle, sheep, goats, and donkeys, while black-backed jackals predated sheep, goats, and poultry. About 5.4% of livestock owned by the respondents were predated by both carnivores from 2021–2023, and responsible for 36,796 USD in economic loss. Higher spotted hyenas’ predation was recorded from the enclosure during the wet season, while black-backed jackals attacked mainly from the inside of BCCA during the dry season. In total, livestock predation strongly affects local communities’ livelihoods around BCCA. Hence, for the sustainable coexistence of carnivores and local communities living around BCCA, proper compensation of the economic loss and appropriate conflict mitigation practices should be promoted and implemented.

ALMOST ANALYTIC EXTENSIONS AND ULTRADIFFERENTIABLE FUNCTIONS

2025-01-25T13:58:55+00:00

The notion of almost analytic extension has found numerous applications in various fields. This paper provides a comprehensive characterization
of ultradifferentiable functions by examining the existence of almost analytic
extensions.

FUZZY POINTS IN FUZZY GEOMETRY REDEFINED

2025-01-28T07:08:24+00:00

In this paper, we introduce a new approach to study several notions of fuzzy geometry. This approach
uses a modied denition of fuzzy points using connected and simply connected instead of convexity
on the study of fuzzy geometry. We have shown that the center of a fuzzy circle is a fuzzy point.

Review on Epigenetic Modification Mechanisms and their Application for the Genetic Improvement of Plants

2025-01-31T12:55:17+00:00

The study of epigenetics is concerned with the changes in gene expression that occur without altering DNA sequences. DNA methylation, histone modification, and RNA interference are the major epigenetic mechanisms that play a transgenerational role in organism development. These modifications are dynamic and reversible, which makes them significant to regulating gene expression, growth, and development in plants. DNA methylation emerges as one of the most important molecular mechanism and it has a complex process through the involvement of DNA methyl transferases and ten-eleven translocations (TET). It has a great role in plant stress responses and crop improvement. Histone modification is the second regulatory mechanisms that modulate the chromatin structure and thereby affect various processes, such as gene transcription, DNA replication, DNA recombination, and DNA repair in cells. It is involved in different plant responses to biotic and abiotic stresses. The exploration of non-coding RNAs brings attention to their roles in post-transcriptional gene regulation. Small RNA-mediated epigenetic modification is a potential in understanding and manipulating plant gene expression. By understanding these epigenetic mechanisms, researchers can develop innovative strategies to improve crop yield, quality, and stress tolerance. This review aims to provide a comprehensive overview of epigenetic mechanisms in plants and their potential applications in agriculture. By exploring the intricate interplay between genetic and epigenetic factors, we can unlock the full potential of plants to meet the growing global food demand and adapt to changing environmental conditions.