Antifungal compounds, GC-MS analysis and toxicity assessment of methanolic extracts of Trichoderma species in an animal model

Fungi of the genus Trichoderma have been marketed for the management of diseases of crops. However, some Trichoderma species may produce toxic secondary metabolites and it should receive due attention to ensure human safety. In this study, we investigated the in vitro antagonistic potential of T. asperellum AU131 and T. longibrachiatum AU158 as microbial biocontrol agents (MBCAs) against Fusarium xylarioides and the associated antagonistic mechanism with bioactive substances. Swiss albino mice were used to evaluate the in vivo toxicity and pathogenicity of T. asperellum AU131 and T. longibrachiatum AU158 methanolic extracts and spore suspensions, respectively, in a preliminary safety assessment for use as biofungicides. Gas Chromatography-Mass Spectrometry (GC-MS) was used to profile volatile organic metabolites (VOCs) present in the methanolic extracts. The agar diffusion assay of the methanolic extracts from both T. asperellum AU131 and T. longibrachiatum AU158 were effective at a concentration of 200 mu g/mL (1x10(7) spores/mL), causing 62.5%, and 74.3% inhibition, respectively. A GC-MS analysis of methanolic extracts from both bioagents identified 23 VOCs which classified as alcohols, acids, sesquiterpenes, ketones and aromatic compounds. The oral administration of methanolic extracts and spore suspensions of each Trichoderma species to female Swiss albino mice over 14 days did not show any significant signs of toxicity, mortality or changes to body weight. It can be concluded that the tested spore suspensions and methanolic extracts were not pathogenic or toxic, respectively, when administered to Swiss albino mice at various doses

Indoor air bacterial load and antibiotic susceptibility pattern of isolates at Adare General Hospital in Hawassa, Ethiopia

BackgroundAir is the agent of pathogenic microbes that cause significant problems in the hospital environment. Multidrug resistance poses a major therapeutic challenge to these airborne microorganisms in hospital indoor environments.Method and materialsThis study was conducted at Adare General Hospital in Hawassa City, Sidama, Ethiopia. A cross-sectional study was conducted. The proportional allocation method was used to select the sampled 50 rooms from the total available rooms in each category of wards and staff offices. A total of 100 indoor air samples were collected using settle plates in all units twice a day, morning (9:00–4:00 a.m.) and afternoon (3:00–4:00 p.m.). The types and number of colonies were determined in the laboratory, and the pathogenic bacteria were isolated by appropriate bacteriological techniques. Antimicrobial susceptibility testing was performed on Mueller-Hinton agar for each potentially pathogenic bacterium isolated. For each bacterium, a total of 12 antibiotics were tested using the Kirby-Bauer disk diffusion method. The test organism was adjusted to McFarland turbidity standards of 0.5. Data were entered and analyzed using the SPSS version 25 window. Descriptive analysis and one-way analysis of variance were performed.ResultsThe indoor air bacterial load of Adare General Hospital was found in the range between 210 and 3,224 CFU/m3. The highest indoor air bacterial load was identified from the gynecology ward with a mean of 2,542.5CFU/m3 at p < 0.05. From 100 indoor air samples, a total of 116 bacterial pathogen isolates were obtained. Gram-positive isolates predominated at 72.4%, of which 37.1% were Staphylococcus aureus, 26.7% were coagulase-negative Staphylococci, and the rest 8.6% were Streptococcus pyogenes. The isolation of pathogenic bacteria Staphylococcus aureus and coagulase-negative Staphylococci showed a high level of resistance to ampicillin.ConclusionA high bacterial load was found in the study area as compared to different indoor air biological standards. Staphylococcus aureus and coagulase-negative Staphylococci were the isolated predominant bacteria. Attention should be given to preventing and minimizing those environmental factors that favor the multiplication of bacteria in the indoor environment of a hospital for the safe health of patients, visitors, and staff

Modeling Thermomechanical Stress with H13 Tool Steel Material Response for Rolling Die under Hot Milling

For the extreme pressure and temperature arising in the hot rolling process, thermomechanical (TM) models are used to predict the residual stresses on the surface of the die because a quantification of the TM stresses allows a prediction of the life span of the rolling die. As the accuracy and consistency of models developed in this area show a large variation due to the considered parameters, conditions, and assumptions, the capability of the developed models needs to be verified for a particular set of circumstances. In this study, new constitutive equations are proposed and a model consisting of five sub-models that computes temperature distribution, thermal stresses, mechanical stresses, and thermomechanical stress for the rolling die under continuous casting application has been developed and presented in this paper. The first sub-model describes the temperature distribution on the rolling die surface by accounting for the effects of different process parameters such as the initial temperature of the slab, reduction ratio, and the rolling speed, while the second and the third sub-models describe the thermal cyclic stress and the elasticity deformation of mechanical stress, respectively. Furthermore, the fourth sub-model describes the TM stress generation through inheriting numerical approaches, and the last sub-model is developed for the H13 tool material response at a high temperature. To verify the developed analytical models, a finite element simulation and the experimental data are considered. The analytical models are computed using Python, and the ABAQUS software has been used for the finite element simulations. The results show a good agreement with the finite element simulation and experimental data.publishedVersio

Numerical Modeling Rolling Contact Problem and Elasticity Deformation of Rolling Die under Hot Milling

In metalworking, rolling is a metal-forming process in which slab is passed through one or more pairs of the rolling dies to reduce the thickness and to make the thickness uniform. Modeling of rolling die contact with the slab primarily needs to describe the Tribology of contact phenomena. The central concern of numerical modeling is used in this work to indicate a set of equations, derived from the contact principle, that transfer the physical event into the mathematical equations. Continuum rolling contact phenomena is considered to explain how a contact region is formed between rolling die and slab and how the tangential force is distributed over the contact area with coefficient of friction. At the end, elasticity stress behavior of rolling die contact with the slab for a number of cyclic loads is modeled. The model includes new proposed constitutive equations for discontinuity of the velocity–pressure distribution in rolling contact from the entry side to exit side of the neutral point. To verify the model, finite element simulation and experimental data from the literature are considered. The results show good agreement with finite element simulation and experimental data

Investigation of Soil Physicochemical Effects on the Corrosion of Buried Iron Pipes

Soil corrosivity was an active problem of water pipeline damaged by corrosion that affects the performance of pipe manufacturers. In Addis ababa, groundwater pipelines were facing breakage and like due to corrosion damage of the pipes. The population of nearly four million were facing a shortage of clean and continuous water supply. Maintenace and replacing old pipes with new ones increased additional cost and delay of water supply for the city. For this investigation of corrosion, causes were conducted which soil property is the one factor. Investigation of soil corrosivity for a given specific location before installation is important to design robust pipes that can serve for long life. Soil physicochemical behaviors of the soil parameters were pH, moisture content, and electrical resistivity for any type of soil. In addition, soil bulk density, total nitrogen, soil texture, and electrical conductivity were also the main factors to be studied. The laboratory result indicated that pH of 6.98-7.04, moisture content of 23.7-37.5%, and electrical conductivity of 0.105-313 ds/m were observed. Total nitrogen was small as 0.06-0.10 for a type of soil were class and loam soils. From the analysis of eight soil samples taken from different cities. The results show that the corrosivity behavior of buried iron pipes in the capital city of Ethiopia was moderately corrosive. As confirmed from various soil samples tested from corroded pipes at different depths of 40, 80, and 120 cm. The influence of soil corrosiveness factors initiates pits formation and propagates its width and depth on the surface of pipes

Altering of the sprayed wall after indoor residual spraying and associated factors among households in Boricha district, Sidama regional state, Ethiopia, 2019: community-based cross-sectional study

Abstract Background Indoor residual spraying (IRS) has been the main tool used to control malaria. Reducing the life span and the density of the vector mosquitoes are direct effects of IRS towards restricting malaria transmission. Residents must not wash or re-plaster walls after the spray application for at least 6 months to fight against malaria with IRS. This study sought to assess the alteration of the sprayed wall after the IRS operation and associated factors among households in the Boricha district. Methods Community-based cross-sectional study was conducted among 608 households selected using multi-stage sampling. A structured interviewer-administered questionnaire was used to collect data. Data were analysed by SPSS version 25. Both bivariable and multivariable logistic regression analysis was done. Finally, the strength of the association was measured based on AOR with 95% CI and statistical significance was declared at a p-value less than 0.05. Result From the total of 608 sprayed houses included in the study, 37.3% (95% CI: 33.41% – 41.15%) were found to have altered sprayed walls. The highest class of wealth index category (AOR = 2.50; 95% CI: 1.19, 5.16), low level of comprehensive knowledge about IRS (AOR = 6.08; 95% CI: 3.37, 10.94), did not get information within 2 weeks before spray (AOR = 2.09; 95% CI: 1.43, 3.05), absence of supervision after the spray operation (AOR = 1.77; 95% CI: 1.27, 2.73) and walking distance to nearest health facility (AOR = 2.39; 95% CI: 1.63, 3.35) remained significant factors of altering of the sprayed wall after IRS. Conclusion The prevalence of alteration was relatively high. The highest socio-economic status, poor knowledge about indoor residual spraying, lack of information about IRS within two weeks before spray, absence of supervision after IRS, and walking distance of more than 30 min to reach the nearest health post were the factors affecting the alteration status of the sprayed wall. Future efforts to focus on successive awareness creation activities should be done before and after IRS operation to the community by concerned bodies

Utilization of Insecticide-Treated Nets in Households for Under-5 Children and Associated Factors in East Mesekan District, Gurage Zone, Southern Ethiopia

Introduction: Insecticide-treated nets (ITNs) are widely used tools that have been proven effective in preventing and controlling malaria. However, usage varies among households and can greatly affect the benefits of ITNs. Thus, this study aimed to assess the household utilization of insecticide-treated nets and its associated factors for under-5 children. Methods: A cross-sectional study was conducted in March-April 2020 in the East Mesekan district. A total of 591 households with under-5 children were chosen by using a systematic random sampling approach for the interviews. The data was collected using a pretested questionnaire. Epi-Data version 3.1 was used to enter data and SPSS version 21 for analysis. A P -value of .05 was considered statistically significant. Results: In this study, 58.2% (95% CI: [54.1%-62.2%]) of household participants used ITN for children under 5 years of age while sleeping the night before the survey. The study participants’ overall knowledge and practice of malaria prevention were 27.1% and 23.9%, respectively. Having a family size of less than 5 (AOR = 0.60, 95% CI: [0.37-0.98]) and complaints of skin irritation (AOR = 0.43, 95% CI: [0.29-0.63]) significantly decreased ITN utilization. However, having 1 ITN (AOR = 2.15, 95% CI: [1.15-4.02]) or 2 ITNs (AOR = 2.58, 95% CI: [1.51-4.39]), as well as low (AOR = 2.07, 95% CI: [1.33-3.20]) and medium (AOR = 1.83, 95% CI: [1.11-3.02]) knowledge of ITN importance, increased ITN utilization significantly. Conclusions: The households’ use of ITNs for children under the age of 5 was inadequate. It was significantly associated with having a family size of less than 5, complaints of skin irritation, owning 1 or 2 ITNs, and having low and medium knowledge of its importance. It is recommended that continuous and progressive health awareness about the consistent use of ITN for malaria prevention in the study area be promoted

Effect of temperature and pH on <i>Trichoderma</i> species growth.

Different alphabets depicted in superscript indicate mean treatments that are significantly different according to Tukey’s HSD posthoc test at p ≤ 0.05 each value is an average of 3 replicate samples ± standard error.</p

Volatile organic compounds of <i>T</i>. <i>asperellum</i> AU131 and <i>T</i>. <i>longibrachiatum</i> AU158 identified by GC-MS.

Volatile organic compounds of T. asperellum AU131 and T. longibrachiatum AU158 identified by GC-MS.</p

Fig 3 -

Chromatograms of the volatile organic compounds identified from T. asperellum AU131 (A) and T. longibrachiatum AU158 (B) crude extracts.</p