Numerical study on effect of constant and variable axial loads on RC column subjected to blast load.

Explosion is an instant release of potential energy, heat, temperature and sound producing a pressure wave that travels away from the source radially on which the resulting force the blast wave is a blast load. Besides this, column especially external column as a main load bearing compressive structural component in buildings is the most critical structural element vulnerable to explosion and require an in-depth investigation on its performance against blast loads. Despite this, currently there is perceived gap and meagre of researches regarding numerical investigation on effect of presence of constant and variable axial loads on reinforced concrete column when subjected to blast load. In this study, the responses of reinforced concrete column under different scaled distance blast load scenarios accompanied by constant and axial loads were investigated. The finite element method of structural analysis was employed accompanied by nonlinear explicit time integration software LS-DYNA. The numerical analysis result revealed that RC columns subjected to large axial loads accompanied by small scaled distance blast scenario made the reinforced concrete column to suffer severe damages including crushing of concrete especially direct shear failures and breaking of reinforcing steel bars. In addition to this, comparing the nature and behaviour of variable axial loads with constant axial loads, the former loading case revealed larger nodal displacement values along height of column, and a higher displacement-time history curve was traced. On the other hand, the damage propagation nature of RC columns loaded with variable axial load was slow and progressive and different with RC columns with constant axial loads accompanied by small scaled blast scenario which was rendered to have a severely crushed concrete element without bending actions leaving the entire column inadequate for service.

Evaluation of quality and antimicrobial efficacy of locally manufactured alcohol-based hand sanitizers marketed in Addis Ababa, Ethiopia in the era of COVID-19.

BACKGROUND: The coronavirus disease 2019 (COVID-19) has been rapidly spreading across the globe since the World Health Organization (WHO) has declared the disease outbreak as a global pandemic on March 11, 2020. Hand hygiene, via either regular handwashing with soap and water or using hand sanitizers, is among the various measures that need to be followed to control the outbreak of the disease. Alcohol-based hand sanitizers (ABHS) are the "gold standard" for hand disinfection because of their broad antimicrobial spectrum of activity, easy availability, better safety profile, and general acceptability to users. This study aimed at evaluating the physicochemical quality and antimicrobial efficacy of the locally manufactured ABHS marketed in Addis Ababa, Ethiopia. METHODS: A cross-sectional survey was used to collect ABHS from Addis Ababa marketplaces. A total of 25 sample products were randomly selected from different categories of hand sanitizer manufacturers. The physicochemical evaluation of the products was carried out as per the United States Pharmacopoeia and WHO standards. Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella spp., and Shigella spp clinical isolates were used for the antimicrobial efficacy test. RESULTS: The Fourier Transform Infrared result confirmed that all the test products met the identification test for ethanol. The majority (68%) of ABHS complied with the test for ethanol content (75-85% v/v). However, only 3 products fulfilled the hydrogen peroxide content (0.112-0.137% v/v). LPC307 showed the maximum zone of inhibition of 12 mm against Escherichia coli whereas MPC204 exhibited only 3 mm. LPC101 was found to be more sensitive to Shigella and Klebsiella Spp with minimum inhibitory concentration values of 20% and 10%, respectively. The sample product LPC101 showed a minimum bactericidal concentration of 20% against Escherichia coli, Pseudomonas aeruginosa, and Klebsiella spp. CONCLUSION: One-third of the tested ABHS did not comply with the WHO ethanol content limit and the majority of the products failed to meet the label claim for hydrogen peroxide content. Besides, nearly all products proved that they have activity against all the tested pathogenic microorganisms at a minimum concentration from 10 to 80%; though, they did not show 99.9% bacteriostatic or bactericidal activities as claimed. The study findings suggested regular monitoring of the quality of marketed ABHS considering the current wide use of these products.

Seroconfirmed Typhoid Fever and Knowledge, Attitude, and Practices among Febrile Patients Attending at Injibara General Hospital, Northwest Ethiopia.

INTRODUCTION: Typhoid fever (TF) is a febrile global health problem caused by Salmonella enterica serovar Typhi (S. Typhi) with relatively high prevalence in low- and middle-income countries including Ethiopia. Identifying local prevalence and gaps in knowledge, attitude, and practice (KAP) towards TF is recommended by the World Health Organization to implement preventive measures. Therefore, this study determined the prevalence of S. Typhi and KAP of febrile patients towards TF in Injibara General Hospital, Northwest Ethiopia. METHODS: Hospital-based cross-sectional study was conducted from January to March 2020. A total of 237 patients were included conveniently. Data on KAP and demographic variables were collected using a structured questionnaire by face-to-face interview. After the interview, 5 ml venous blood was collected and processed using the Widal test following the manufacturer's instruction. Mean scores and percentages were used to determine the level of KAP. Multivariable analysis was done to correlate KAPs with TF. P value < 0.05 was considered statistically significant. RESULTS: The overall prevalence of S. Typhi was 25.7%. The highest seroprevalence was observed among the age group of 30-34 years (33.3%) and patients with no education. The majority of participants know the major ways of TF transmission (59.1-90.7%) and prevention (81.4%) methods. However, the misconception on the route of TF transmission was observed in 13.5-36.7% of participants. About 65.4% and 67.5% of study participants were considered knowledgeable and had good preventive practice towards TF, respectively. Being a student (AOR = 0.227, CI = 0.053 - 0.965) and considering mosquito bite as transmission routes (AOR = 2.618, CI = 1.097 - 6.248) were significantly associated with TF. CONCLUSION: High S. Typhi prevalence was observed in the study area. Moreover, the misconception on the transmission of typhoid fever and educational level was a risk factor for TF. Thus, health facilities should incorporate topics on typhoid fever as part of their health education system within health facilities and in the community.