Green synthesis of zinc oxide nanostructures and investigation of their photocatalytic and bactericidal applications

We report a facile one-pot green synthesis of zinc oxide (ZnO) nanostructures using aqueous leaf extract of Dolichos Lablab L. as the reducing and capping agent. The optical properties, structure and morphology of the as-synthesized ZnO nanostructures have been characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) supported with energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). TEM analysis revealed that the as-synthesized ZnO nanostructures have an average particle diameter of 29 nm. XRD patterns confirmed the formation of phase-pure ZnO nanostructures with a hexagonal wurtzite structure. The synthesized ZnO nanostructures were used as a catalyst in the photodegradation of methylene blue (MB), rhodamine B (RhB) and orange II (OII) under visible and near-UV irradiation. The results showed the highest efficiency of photodegradation of ZnO nanostructures for MB (80%), RhB (95%) and OII (66%) at pH values of 11, 9 and 5, respectively, in a 210 min time interval. In addition, the antimicrobial activity of the ZnO nanostructures using the agar well diffusion method against Bacillus pumilus and Sphingomonas paucimobilis showed the highest zones of inhibition of 18 mm and 20 mm, respectively. Hence, ZnO nanostructures have the potential to be used as a photocatalyst and bactericidal component.

We report a facile one-pot green synthesis of zinc oxide (ZnO) nanostructures using aqueous leaf extract of Dolichos Lablab L. as the reducing and capping agent.     

Green syntheses of silver nanoparticle decorated reduced graphene oxide using l-methionine as a reducing and stabilizing agent for enhanced catalytic hydrogenation of 4-nitrophenol and antibacterial activity

Herein, we have reported a facile and green synthesis approach of Ag NP decorated reduced graphene oxide (RGO) through an in situ self-assembly method in the presence of l-methionine (l-Met) as reducing and stabilizing agent. The electronic properties, crystal structure, and morphology of the as-synthesized RGO–Ag nanocomposite were investigated by UV-Visible (UV-Vis) spectroscopy, Fourier transform-infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. UV-Vis and FTIR show the effective reduction of GO and the formation of Ag NPs using l-Met. FESEM, TEM, and XRD analysis show the successful impregnation of Ag NPs into RGO with a 23 nm average crystallite size. The RGO–Ag nanocomposite with NaBH₄ shows a fast-catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AMP). The enhanced catalytic activity of RGO–Ag nanocomposites can be attributed to the synergistic effect of improved adsorption capacity and the absence of agglomeration of Ag nanoparticles. Moreover, RGO–Ag showed strong antibacterial activity against B. subtilis and E. coli.

Herein, we have reported a facile and green synthesis approach of Ag NP decorated reduced graphene oxide (RGO) through an in situ self-assembly method in the presence of l-methionine (l-Met) as reducing and stabilizing agent.     

Relapsing fever in children--demographic, social and clinical features.

Louse-borne relapsing fever (LBRF) is an acute febrile illness endemic Ethiopia. To date reports of childhood LBRF are few. The demographic, social and clinical features of eighty children with LBRF admitted to Ethio-Swedish Children's Hospital, Addis Abeba between 1989 and 1991 is presented. The mean age of patients was 8.8 years (range 4 months to 15 years). The male to female ratio was 1.2:1. Seventy-seven (97%) patients came from Addis Abeba. They came from poor families living in overcrowded homes. Fever, headache, right upper quadrant pain, chills and rigors were common symptoms. Fever and hepatosplenomegaly were common signs. Three drug regimens were used in the treatment of patients. A combination of penicillin and tetracycline, chloramphenicol alone and erythromycin alone, all given for 3 days. There was only one death. The literature on LBRF in adults is reviewed and the results are compared (1).     

The invitro assessment of antibacterial effect of papaya seed extract against bacterial pathogens isolated from urine, wound and stool

BACKGROUND: Carica papaya family Caricaceacae is one of the herbal remedies, which has recently become a subject of research focus. It is used in traditional medicine for variety of purposes in treating infectious and noninfectious diseases. OBJECTIVE: The objective of this study was to assess the antibacterial effect of papaya seed extract against bacterial pathogens isolated from wound, urine and stool. METHODS: This analytical experimental study was conducted in Jimma University, School of Medical Laboratory Technology, Microbiology laboratory between February to March 2005. The antibacterial activity of methanol extract of papaya seed was investigated against specific pathogenic bacteria isolated from wound, urine and stool by an agar dilution technique and the crude preparation was assessed by an agar diffusion technique. The growth or inhibition of control strains of Escherichia coli, Staphylococcus aureus, Salmonella typhi, and Pseudomonas aeruginosa as well as the clinical isolates of these bacteria were determined in growth media. RESULTS: Results obtained in this study indicate that the minimum inhibitory concentration of papaya seed extract for 50% of the test bacteria was 18.38mg/ml and for S. typhi the MIC was at 11.8 mg/ml of extract. However, the growth inhibitory effect of papaya seed extract was not observed for P. aeruginosa up to 26.25 mg /ml of extract. Even though, the minimum bactericidal concentration is higher than the minimum inhibitory concentration of papaya seed extract (13.13 mg/ml, 11.8 mg/ml respectively) against S. typhi control and clinical isolates, the minimum bactericidal concentration for 50% of the tested bacteria was found to be similar with the minimum inhibitory concentration of the test bacteria, CONCLUSION: Papaya seed could be used as an effective antibacterial agent for the tested organisms. Nevertheless, preclinical studies including invivo animal models and clinical trial on the effect of the seed are essential before advocating large-scale therapy.     

Prevalence and associated factors of treatment failure among HIV/AIDS patients on HAART attending University of Gondar Referral Hospital Northwest Ethiopia

Background

The initiation of highly active antiretroviral therapy (HAART) plays a significant role in the clinical management of HIV infected people by preventing morbidity and mortality. This benefit becomes, the most terrible when treatment failure develops. Thus, this research aims to assess the prevalence and associated factors of treatment failure among HIV/AIDS patients on HAART attending University of Gondar Referral Hospital Northwest Ethiopia.

Results

Patients on ART with a minimum of 6?months and up to 12?years of treatment were being enrolled. The prevalence of treatment failure, immunological failure and virological failure among people living with HIV/AIDS attending University of Gondar referral hospital were 20.3, 13.2, and 14.7%, respectively. Patients who had no formal education (Adjusted odds ratio (AOR): 3.8; 95% CI, 1.05–13.77), primary level education (AOR: 4.2; 95% CI, 1.16–15.01) and duration on ART <?6?years (AOR: 2.1; 95%CI, 1.12–3.81) were a significant risk factor. However, initial adult regimen D4T?+? 3TC+ EFV (AOR: 0.025; 95% CI, 0.002–0.36), AZT +3TC?+?NVP (AOR: 0.07; 95% CI, 0.01–0.71), AZT?+? 3TC?+?EFV (AOR: 0.046; 95% CI, 0.004–0.57) andTDF+3TC?+?EFV (AOR: 0.04; 95% CI, 0.004–0.46) were significantly protective for treatment failure.

Conclusions

Timely and early identification of associated factors and monitoring antiretroviral therapy treatment failure should be done to enhance the benefit and to prevent further complication of the patients. It is preferable to initiate ART using any one of the following ART regimens: AZT +3TC?+?NVP, AZT?+?3TC?+?EFV and TDF?+?3TC?+?EFV to prevent treatment failure. Since the prevalence of this treatment failure and its associated factor may be different from other ART centers and community in Ethiopia, further national representative institutional based cross-sectional researches are needed across all ART centers of Ethiopia in order to determine the prevalence of treatment failure and its associated factors.

     

Insights into SARS-CoV-2 in Angola during the COVID-19 peak: Molecular epidemiology and genome surveillance

Background

In Angola, COVID-19 cases have been reported in all provinces, resulting in >105,000 cases and >1900 deaths. However, no detailed genomic surveillance into the introduction and spread of the SARS-CoV-2 virus has been conducted in Angola. We aimed to investigate the emergence and epidemic progression during the peak of the COVID-19 pandemic in Angola.

Methods

We generated 1210 whole-genome SARS-CoV-2 sequences, contributing West African data to the global context, that were phylogenetically compared against global strains. Virus movement events were inferred using ancestral state reconstruction.

Results

The epidemic in Angola was marked by four distinct waves of infection, dominated by 12 virus lineages, including VOCs, VOIs, and the VUM C.16, which was unique to South-Western Africa and circulated for an extended period within the region. Virus exchanges occurred between Angola and its neighboring countries, and strong links with Brazil and Portugal reflected the historical and cultural ties shared between these countries. The first case likely originated from southern Africa.

Conclusion

A lack of a robust genome surveillance network and strong dependence on out-of-country sequencing limit real-time data generation to achieve timely disease outbreak responses, which remains of the utmost importance to mitigate future disease outbreaks in Angola.     

Prevention and treatment of cardiovascular disease in Ethiopia: a cost-effectiveness analysis

Background

The coverage of prevention and treatment strategies for ischemic heart disease and stroke is very low in Ethiopia. In view of Ethiopia’s meager healthcare budget, it is important to identify the most cost-effective interventions for further scale-up. This paper’s objective is to assess cost-effectiveness of prevention and treatment of ischemic heart disease (IHD) and stroke in an Ethiopian setting.

Methods

Fifteen single interventions and sixteen intervention packages were assessed from a healthcare provider perspective. The World Health Organization’s Choosing Interventions that are Cost-Effective model for cardiovascular disease was updated with available country-specific inputs, including demography, mortality and price of traded and non-traded goods. Costs and health benefits were discounted at 3 % per year. Incremental cost-effectiveness ratios are reported in US$ per disability adjusted life year (DALY) averted. Sensitivity analysis was undertaken to assess robustness of our results.

Results

Combination drug treatment for individuals having >35 % absolute risk of a CVD event in the next 10 years is the most cost-effective intervention. This intervention costs US$67 per DALY averted and about US$7 million annually. Treatment of acute myocardial infarction (AMI) (costing US$1000–US$7530 per DALY averted) and secondary prevention of IHD and stroke (costing US$1060–US$10,340 per DALY averted) become more efficient when delivered in integrated packages. At an annual willingness-to-pay (WTP) level of about US$3 million, a package consisting of aspirin, streptokinase, ACE-inhibitor and beta-blocker for AMI has the highest probability of being most cost-effective, whereas as WTP increases to > US$7 million, combination drug treatment to individuals having >35 % absolute risk stands out as the most cost-effective strategy. Cost-effectiveness ratios were relatively more sensitive to halving the effectiveness estimates as compared with doubling the price of drugs and laboratory tests.

Conclusions

In Ethiopia, the escalating burden of CVD and its risk factors warrants timely action. We have demonstrated that selected CVD intervention packages could be scaled up at a modest budget increase. The level of willingness-to-pay has important implications for interventions’ probability of being cost-effective. The study provides valuable evidence for setting priorities in an essential healthcare package for CVD in Ethiopia.

     

Trends,causes, and risk factors of mortality among children under 5 in Ethiopia, 1990–2013: findings from the Global Burden of Disease Study 2013

Background

Ethiopia has made remarkable progress in reducing child mortality over the last two decades. However, the under-5 mortality rate in Ethiopia is still higher than the under-5 mortality rates of several low- and middle-income countries (LMIC). On the other hand, the patterns and causes of child mortality have not been well investigated in Ethiopia. The objective of this study was to investigate the mortality trend, causes of death, and risk factors among children under 5 in Ethiopia during 1990–2013.

Methods

We used Global Burden of Disease (GBD) 2013 data. Spatiotemporal Gaussian Process Regression (GPR) was applied to generate best estimates of child mortality with 95% uncertainty intervals (UI). Causes of death by age groups, sex, and year were measured using Cause of Death Ensemble modeling (CODEm). For estimation of HIV/AIDS mortality rate, the modified UNAIDS EPP-SPECTRUM suite model was used.

Results

Between 1990 and 2013 the under-5 mortality rate declined from 203.9 deaths/1000 live births to 74.4 deaths/1000 live births with an annual rate of change of 4.6%, yielding a total reduction of 64%. Similarly, child (1–4 years), post-neonatal, and neonatal mortality rates declined by 75%, 64%, and 52%, respectively, between 1990 and 2013. Lower respiratory tract infection (LRI), diarrheal diseases, and neonatal syndromes (preterm birth complications, neonatal encephalopathy, neonatal sepsis, and other neonatal disorders) accounted for 54% of the total under-5 deaths in 2013. Under-5 mortality rates due to measles, diarrhea, malaria, protein-energy malnutrition, and iron-deficiency anemia declined by more than two-thirds between 1990 and 2013. Among the causes of under-5 deaths, neonatal syndromes such as sepsis, preterm birth complications, and birth asphyxia ranked third to fifth in 2013.Of all risk-attributable deaths in 1990, 25% of the total under-5 deaths (112,288/435,962) and 48% (112,288/232,199) of the deaths due to diarrhea, LRI, and other common infections were attributable to childhood wasting. Similarly, 19% (43,759/229,333) of the total under-5 deaths and 45% (43,759/97,963) of the deaths due to diarrhea and LRI were attributable to wasting in 2013. Of the total diarrheal disease- and LRI-related deaths (n?=?97,963) in 2013, 59% (57,923/97,963) of them were attributable to unsafe water supply, unsafe sanitation, household air pollution, and no handwashing with soap.

Conclusions

LRI, diarrheal diseases, and neonatal syndromes remain the major causes of under-5 deaths in Ethiopia. These findings call for better-integrated newborn and child survival interventions focusing on the main risk factors.