Engineering Characterisation of Aggregates from Some Selected Areas in Kumasi, Ghana

The increase in engineering projects translates to an increase in demand for construction materials, for example, aggregates which are a major component in concrete works. There are many quarries in the Kumasi area which produce aggregates for use in construction works. However, there is no readily available information on the geological and geotechnical properties of these aggregates for use by engineers during the planning, design and construction of projects. This project therefore sought to characterise the aggregate from selected areas (close to some major quarries) in Kumasi based on their geological and engineering properties for construction purposes. Results of the study indicate that Aggregates from sampling locations KP and CS passed the FI test with those from CS being the only ones to pass for EI, making them the best aggregates in terms of Flakiness and Elongation Indices. The aggregates from all the sampling locations passed for the Specific Gravity and Water Absorption tests with CS aggregates giving the best results indicating high strength and good rate of water absorption. Aggregate from sampling location NM gave the best result for the Aggregate Impact Value test indicating high resistance to sudden impacts and shocks. With the Ten Percent Fines Value and the Aggregate Crushing Value Tests, CS yet again produced the aggregates with the best results. The aggregate gave a very high result even under the wet/soaked condition when all the others were giving very low results. Aggregates from this sampling locations can withstand loading gradual compression better than the rest. Finally, the KP aggregates gave the best results for the Los Angeles Abrasion Value which suggests such materials to be the hardest and toughest to resist crushing, degradation and disintegration. Aggregates from the CS, however gave the second best results. From the study, it was concluded that the most suitable location to obtain good quality aggregates is around CS as its aggregates gave the best results in almost all the tests

Paradoxical reactions in Buruli ulcer after initiation of antibiotic therapy: Relationship to bacterial load.

BACKGROUND: We investigated the relationship between bacterial load in Buruli ulcer (BU) lesions and the development of paradoxical reaction following initiation of antibiotic treatment. METHODS: This was a longitudinal study involving BU patients from June 2013 to June 2017. Fine needle aspirates (FNA) and swab samples were obtained to establish the diagnosis of BU by PCR. Additional samples were obtained at baseline, during and after treatment (if the lesion had not healed) for microscopy, culture and combined 16S rRNA reverse transcriptase/ IS2404 qPCR assay. Patients were followed up at regular intervals until complete healing. RESULTS: Forty-seven of 354 patients (13%) with PCR confirmed BU had a PR, occurring between 2 and 42 (median 6) weeks after treatment initiation. The bacterial load, the proportion of patients with positive M. ulcerans culture (15/34 (44%) vs 29/119 (24%), p = 0.025) and the proportion with positive microscopy results (19/31 (61%) vs 28/90 (31%), p = 0.003) before initiation of treatment were significantly higher in the PR compared to the no PR group. Plaques (OR 5.12; 95% CI 2.26-11.61; p<0.001), oedematous (OR 4.23; 95% CI 1.43-12.5; p = 0.009) and category II lesions (OR 2.26; 95% CI 1.14-4.48; p = 0.02) were strongly associated with the occurrence of PR. The median time to complete healing (28 vs 13 weeks, p <0.001) was significantly longer in the PR group. CONCLUSIONS: Buruli ulcer patients who develop PR are characterized by high bacterial load in lesion samples taken at baseline and a higher rate of positive M. ulcerans culture. Occurrence of a PR was associated with delayed healing. TRIAL REGISTRATION: ClinicalTrials.gov NCT02153034

Providing insight into the incubation period of Mycobacterium ulcerans disease: two case reports.

BACKGROUND: Buruli ulcer caused by Mycobacterium ulcerans is endemic in parts of West Africa and is most prevalent among the 5-15 years age group; Buruli ulcer is uncommon among neonates. The mode of transmission and incubation period of Buruli ulcer are unknown. We report two cases of confirmed Buruli ulcer in human immunodeficiency virus-unexposed, vaginally delivered term neonates in Ghana. CASE PRESENTATION: Patient 1: Two weeks after hospital delivery, a baby born to natives of the Ashanti ethnic group of Ghana was noticed by her mother to have a papule with associated edema on the right anterior chest wall and neck that later ulcerated. There was no restriction of neck movements. The diagnosis of Buruli ulcer was confirmed on the basis of a swab sample that had a positive polymerase chain reaction result for the IS2404 repeat sequence of M. ulcerans. Patient 2: This patient, from the Ashanti ethnic group in Ghana, had the mother noticing a swelling in the baby's left gluteal region 4 days after birth. The lesion progressively increased in size to involve almost the entire left gluteal region. Around the same time, the mother noticed a second, smaller lesion on the forehead and left side of neck. The diagnosis of Buruli ulcer was confirmed by polymerase chain reaction when the child was aged 4 weeks. Both patients 1 and 2 were treated with oral rifampicin and clarithromycin at recommended doses for 8 weeks in addition to appropriate daily wound dressing, leading to complete healing. Our report details two cases of polymerase chain reaction-confirmed Buruli ulcer in children whose lesions appeared at ages 14 and 4 days, respectively. The mode of transmission of M. ulcerans infection is unknown, so the incubation period is difficult to estimate and is probably dependent on the infective dose and the age of exposure. In our study, lesions appeared 4 days after birth in patient 2. Unless the infection was acquired in utero, this would be the shortest incubation period ever recorded. CONCLUSIONS: Buruli ulcer should be included in the differential diagnosis of neonates who present with characteristic lesions. The incubation period of Buruli ulcer in neonates is probably shorter than is reported for adults

Sustainable deltas in the Anthropocene

What are the possible trajectories of delta development over the coming decades? Trajectories will be determined by the interactions of biophysical trends such as changing sediment supplies, subsidence due to compaction of sediment and climate change, along with key socio-economic trends of migration and urbanisation, agricultural intensification, demographic transition, economic growth and structural change of the economy. Knowledge and understanding of plausible trajectories can inform management choices for deltas in the Anthropocene, including new policy perspectives and innovative adaptation. The emergence of visionary delta management plans in some large deltas, such as the Bangladesh Delta Plan 2100, is an important and necessary component. This chapter synthesises the state of knowledge and highlights key elements of science that will inform decisions on future management of deltas.<br/

“It was touching”: Experiences and views of students in the June 3 flood and fire disaster relief response volunteerism in Accra, Ghana

Evidence from Africa on the motivations and experiences of student volunteers in community disaster relief response programs are rare. This study explores the experiences and views of the students who volunteered at the emergency mental health relief response site after the June 3, 2015, flood and fire disaster in Accra, and the implications for future professional response work in Ghana. Thematic analysis of 15 qualitative in-depth interviews showed that, overall, the student volunteers were both self-oriented and other-oriented. The students viewed work at the emergency response site as a touching experience and a call of duty. The response work provided the students with practical pathways to linking their clinical and community learning experiences. This study recommends that, rather than an ad hoc response team, the Ghana Psychological Association should consider setting up a standing disaster relief response network to provide mental health relief and recovery response in community emergency situations in Ghana

Antibiotic, Heavy Metal, and Biocide Concentrations in a Wastewater Treatment Plant and Its Receiving Water Body Exceed PNEC Limits:Potential for Antimicrobial Resistance Selective Pressure

Although the rise in antimicrobial resistance has been attributed mainly to the extensive and indiscriminate use of antimicrobials such as antibiotics and biocides in humans, animals and on plants, studies investigating the impact of this use on water environments in Africa are minimal. This study quantified selected antibiotics, heavy metals, and biocides in an urban wastewater treatment plant (WWTP) and its receiving water body in Kwazulu-Natal, South Africa, in the context of the predicted no-effect concentrations (PNEC) for the selection of antimicrobial resistance (AMR). Water samples were collected from the WWTP effluent discharge point and upstream and downstream from this point. Heavy metals were identified and quantified using the United States Environmental Protection Agency (US EPA) method 200.7. Biocides and antibiotic residues were determined using validated ultra-high-performance liquid chromatography with tandem mass spectrometry-based methods. The overall highest mean antibiotic, metal and biocide concentrations were observed for sulfamethoxazole (286.180 &micro;g/L), neodymium (Nd; 27.734 mg/L), and benzalkonium chloride (BAC 12) (7.805 &micro;g/L), respectively. In decreasing order per sampling site, the pollutant concentrations were effluent &gt; downstream &gt; upstream. This implies that the WWTP significantly contributed to the observed pollution in the receiving water. Furthermore, most of the pollutants measured recorded values exceeding the recommended predicted no-effect concentration (PNEC) values, suggesting that the microbes in such water environments were at risk of developing resistance due to the selection pressure exerted by these antimicrobials. Further studies are required to establish such a relationship

Anthroponotic transmission of Cryptosporidium parvum predominates in countries with poorer sanitation - a systematic review and meta-analysis

Background: Globally cryptosporidiosis is one of the commonest causes of mortality in children under 24 months old and may be associated with important longterm health effects. Whilst most strains of Cryptosporidium parvum are zoonotic, C. parvum IIc is almost certainly anthroponotic. The global distribution of this potentially important emerging infection is not clear. Methods: We conducted a systematic review of papers identifying the subtype distribution of C. parvum infections globally. We searched PubMed and Scopus using the following key terms Cryptospor* AND parvum AND (genotyp* OR subtyp* OR gp60). Studies were eligible for inclusion if they had found C. parvum within their human study population and had subtyped some or all of these samples using standard gp60 subtyping. Pooled analyses of the proportion of strains being of the IIc subtype were determined using StatsDirect. Meta-regression analyses were run to determine any association between the relative prevalence of IIc and Gross Domestic Product, proportion of the population with access to improved drinking water and improved sanitation. Results: From an initial 843 studies, 85 were included in further analysis. Cryptosporidium parvum IIc was found in 43 of these 85 studies. Across all studies the pooled estimate of relative prevalence of IIc was 19.0% (95% CI: 12.9–25.9%), but there was substantial heterogeneity. In a meta-regression analysis, the relative proportion of all C. parvum infections being IIc decreased as the percentage of the population with access to improved sanitation increased and was some 3.4 times higher in those studies focussing on HIV-positive indivduals. Conclusions: The anthroponotic C. parvum IIc predominates primarily in lower-income countries with poor sanitation and in HIV-positive individuals. Given the apparent enhanced post-infectious virulence of the other main anthroponotic species of Cryptosporidium (C. hominis), it is important to learn about the impact of this subtype on human health

Anthroponotic transmission of Cryptosporidium parvum predominates in countries with poorer sanitation - a systematic review and meta-analysis

Background: Globally cryptosporidiosis is one of the commonest causes of mortality in children under 24 months old and may be associated with important longterm health effects. Whilst most strains of Cryptosporidium parvum are zoonotic, C. parvum IIc is almost certainly anthroponotic. The global distribution of this potentially important emerging infection is not clear. Methods: We conducted a systematic review of papers identifying the subtype distribution of C. parvum infections globally. We searched PubMed and Scopus using the following key terms Cryptospor* AND parvum AND (genotyp* OR subtyp* OR gp60). Studies were eligible for inclusion if they had found C. parvum within their human study population and had subtyped some or all of these samples using standard gp60 subtyping. Pooled analyses of the proportion of strains being of the IIc subtype were determined using StatsDirect. Meta-regression analyses were run to determine any association between the relative prevalence of IIc and Gross Domestic Product, proportion of the population with access to improved drinking water and improved sanitation. Results: From an initial 843 studies, 85 were included in further analysis. Cryptosporidium parvum IIc was found in 43 of these 85 studies. Across all studies the pooled estimate of relative prevalence of IIc was 19.0% (95% CI: 12.9–25.9%), but there was substantial heterogeneity. In a meta-regression analysis, the relative proportion of all C. parvum infections being IIc decreased as the percentage of the population with access to improved sanitation increased and was some 3.4 times higher in those studies focussing on HIV-positive indivduals. Conclusions: The anthroponotic C. parvum IIc predominates primarily in lower-income countries with poor sanitation and in HIV-positive individuals. Given the apparent enhanced post-infectious virulence of the other main anthroponotic species of Cryptosporidium (C. hominis), it is important to learn about the impact of this subtype on human health

Thermomechanical Characterization of Carbon Black Reinforced Rubbers During Rapid Adiabatic Straining

The thermo-mechanical properties of carbon black reinforced natural and styrene butadiene rubbers are investigated under rapid adiabatic conditions. Eleven carbon black grades with varying surface area and structure properties at 40 parts per hundred (phr) loading are studied and the unreinforced equivalents are included for reference. The results show a strong correlation of the modulus, mechanical hysteresis, temperature rise and calculated crystallinity of the rubbers measured in tensile extension with strain amplification factors. This highlights the influence of matrix overstraining on microstructural deformations of the rubber upon extension. The strain amplification factors are calculated via the Guth-Gold equation directly from carbon black type and loading, allowing a correlation of the fundamental morphological properties of carbon black with thermal and mechanical properties of rubbers upon extension. Analysis of the thermal measurements of the rubber compounds upon extension and retraction and contrasting between crystallizing and non-crystallizing rubbers reveals that a substantial irreversible heat generation is present upon extension of the rubber compounds. These irreversible effects most likely originate from microstructural damage mechanisms which have been proposed to account for the Mullins Effect in particle reinforced rubbers

Fabrication and In vivo Thrombogenecity Testing of Nitric Oxide Generating Artificial Lungs

Hollow fiber artificial lungs are increasingly being used for long-term applications. However, clot formation limits their use to 1–2 weeks. This study investigated the effect of nitric oxide generating (NOgen) hollow fibers on artificial lung thrombogenicity. Silicone hollow fibers were fabricated to incorporate 50 nm copper particles as a catalyst for NO generation from the blood. Fibers with and without (control) these particles were incorporated into artificial lungs with a 0.1 m2 surface area and inserted in circuits coated tip-to-tip with the NOgen material. Circuits (N = 5/each) were attached to rabbits in a pumpless, arterio-venous configuration and run for 4 h at an activated clotting time of 350–400 s. Three control circuits clotted completely, while none of the NOgen circuits failed. Accordingly, blood flows were significantly higher in the NOgen group (95.9 ± 11.7, p \u3c 0.01) compared to the controls (35.2 ± 19.7; mL/min), and resistance was significantly higher in the control group after 4 h (15.38 ± 9.65, p \u3c 0.001) than in NOgen (0.09 ± 0.03; mmHg/mL/min). On the other hand, platelet counts and plasma fibrinogen concentration expressed as percent of baseline in control group (63.7 ± 5.7%, 77.2 ± 5.6%; p \u3c 0.05) were greater than those in the NOgen group (60.4 ± 5.1%, 63.2 ± 3.7%). Plasma copper levels in the NOgen group were 2.8 times baseline at 4 h (132.8 ± 4.5 μg/dL) and unchanged in the controls. This study demonstrates that NO generating gas exchange fibers could be a potentially effective way to control coagulation inside artificial lungs