348 research outputs found

    In vivo anti-malarial potentials of some plants extracts on ICR-mice, Mus musculus

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    Five medicinal plants, Acacia nilotica (Fabaceae), Citrus aurantifolia (Rutaceae), Mangifera indica (Anacardiaceae) Carica papaya (Caricaceae), and Psidium guajava (Myrtaceae) used for the treatment of malaria/ fever by the Hausa people of Kano-Nigeria were selected based on their traditional claims. These were extracted using ethanol. The in vitro antiplasmodial activities of these extracts against laboratory adapted chloroquine susceptible strain of Plasmodium falciparum (3D7) were earlier reported (Dabo et al. 2013). This study was conducted to evaluate the in vivo antiplasmodial activity of four of these extracts using icr mice in the 4-day suppressive test against P. berghei. The extracts evaluated were: Acacia nilotica (Fabaceae) stem extract coded as ANSF1; Citrus aurantifolia (Rutaceae) leaf extract coded as CALF1; Mangifera indica (Anacardiaceae) leaf extract coded as MILF1 and combination of C. aurantifolia, Carica papaya (Caricaceae), M. indica and Psidium guajava (Myrtaceae) leaves extract coded as CBLF1. CALF1, ANSF1 and CBLF1 (combination) exhibited appreciable degree of suppression of 31.06%, 25.16 and %16.35% respectively. MILF1 did not exhibit any suppression against the P. berghei parasite in vivo at all. With the exception of haemoglobin content (P<0.0363), haematological analysis of the various blood parameters of mice in the control and treated mice indicated no statistical difference (P>0.05). Thus it can be concluded that, the apparent absence of changes in haematological profile alongside activities exhibited by CALF1 (Rutaceae), CBLF1 (a combination) and ANSF1 (Fabaceae),) suggest the bio-availability and antiplasmodial activities of the active substances in the plants evaluated.Keywords: Antimalaria; In vivo, Plants Extracts; Mus musculus; Plasmodium berghei

    Generating temperature cycle profile from in-situ climatic condition for accurate prediction of thermo-mechanical degradation of c-Si photovoltaic module

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    The use of climate specific temperature-cycling profile is critical to precisely quantifying the degradation rate and accurately determining the service fatigue life of crystalline silicon photovoltaic (c-Si PV) module operating in various climates. A reliable in-situ outdoor weathering database is pivotal to generating the required climate specific temperature cycle profile. This research utilizes high-resolution data obtained at five minutes interval from installed c-Si PV modules to generate a temperature cycle profile that is representative of a test site in sub-Saharan Africa climate. The study collected a three-year data from 2012 to 2014 on weathering of c-Si PV module located at College of Engineering, KNUST Ghana. The data site is on latitude 6° 40″ N and longitude 1° 37″ W at an elevation of 250 m above sea level. Analysis of the data on temperature variation and thermally induced stresses demonstrates that the region has a profile with a ramp rate of 8.996 °C/h, a hot dwell time of 228 min, cold dwell time of 369 min. Maximum and minimum module temperatures of 58.9 °C and 23.7 °C, respectively; and a cycle time of 86400 s. Comparison with the IEC 61215 standards for terrestrial PV modules qualification reveals percentage changes of – 91%, 2180%, 3590%, 747% for the ramp rate, dwell (hot and cold) and cycle times, respectively. The generated in-situ temperature cycle profile predicts to qualify accurately, c-Si PV modules operating in the sub-Saharan African test site. The systematic technique employed in this study to generate the in-situ temperature cycle profile would be useful to the thermo-mechanical reliability research community. In addition, photovoltaic design and manufacturing engineers may harness the information to create climate specific robust c-Si PV module. Keywords: Temperature cycling, Ramp rates, Temperature gradient, Accelerated Thermal Cycling (ATC), Co-efficient of Thermal Expansion (CTE), Rainflow counting, In-situ data generatio

    Generating temperature cycle profiles of different solar photovoltaic module technologies from in-situ conditions for accurate prediction of thermomechanical degradation

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    The IEC61215 TC200 is a rigorous approval thermal cycling test process that assesses the reliability of solar photovoltaic modules and offers a 25-year lifetime guarantee. However, previous research has shown that installed solar photovoltaic modules experience different rates of degradation depending on the location and climate with most research focused on crystalline silicon. In this study, outdoor weathering data obtained from a rig set up in Kumasi, Ghana for the year 2014, is used to generate thermal cycles for 5 different technologies including monocrystalline, polycrystalline, and amorphous silicon, Copper Indium Gallium Selenide (CIGS) and Heterojunction-With-Intrinsic-Thin-Layer (HIT). From the results, the highest yearly average of the maximum and minimum temperatures, and ramp rates of 54.8oC, 26.1oC, and 6.05oC/h respectively are recorded in CIGS. Polycrystalline recorded the least temperatures of 45.2°C and 23.9°C while HIT recorded the least ramp rate of 4.45°C /h. A comparison between the 2014 and the IEC61215 thermal cycles show extremely wide differences which could explain the higher degradation rates and shorter life of installed solar photovoltaic modules. The procedure adopted in this research can be repeated at different locations to obtain technology-specific thermal cycling profiles to evaluate the thermomechanical damage and predict the life of different solar photovoltaic modules

    Comparative Judgement Modeling to Map Forced Marriage at Local Levels

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    Forcing someone into marriage against their will is a violation of their human rights. In 2021, the county of Nottinghamshire, UK, launched a strategy to tackle forced marriage and violence against women and girls. However, accessing information about where victims are located in the county could compromise their safety, so it is not possible to develop interventions for different areas of the county. Comparative judgement studies offer a way to map the risk of human rights abuses without collecting data that could compromise victim safety. Current methods require studies to have a large number of participants, so we develop a comparative judgement model that provides a more flexible spatial modelling structure and a mechanism to schedule comparisons more effectively. The methods reduce the data collection burden on participants and make a comparative judgement study feasible with a small number of participants. Underpinning these methods is a latent variable representation that improves on the scalability of previous comparative judgement models. We use these methods to map the risk of forced marriage across Nottinghamshire thereby supporting the county's strategy for tackling violence against women and girls.Comment: Submitted. 31 pages, 8 figure

    Assessment of knowledge and treatment practices of hepatitis B infection in children among health professionals in Krachi districts in Ghana:a cross-sectional study

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    Background. Hepatitis B virus (HBV) infection remains one of the neglected infectious diseases. Children infected with HBV are at higher risk of becoming chronic carriers. Barriers to measures against HBV in children are attributed to inadequate knowledge by some health professionals. This study assessed knowledge and treatment practices of HBV in children among health professionals. Materials and Methods. A cross-sectional survey was conducted among health professionals (185) in three districts in Krachi using a structured questionnaire. Stata version 15 was used to analyze participants’ responses on awareness, knowledge, and treatment practices. Pearson’s product-moment correlation was used to determine the relationship between knowledge and treatment practices. Multivariate regression analysis assessed the relationships between variables at P&lt;0.05 and 95% confidence interval. Results. 20% were not aware of HBV in children and 85% had only fair knowledge about HBV in children. Only 29% indicated good knowledge and treatment practices of HBV in children. A unit increase in knowledge of HBV in children leads to a 1.42 unit increase in awareness (P&lt;0.01), and a 1.3 unit increase in treatment practice (P&lt;0.01) of HBV in children. Conclusions. Participants demonstrated only fair knowledge about HBV in children. Seminars and workshops on HBV in children for health professionals must intensify.</p

    Early diagnosis of prostate cancer in the Western Cape

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    Background. Early stage prostate cancer does not cause symptoms, and even metastatic disease may exist for years without causing symptoms or signs. Whereas early stage prostate cancer can be cured with radical prostatectomy or radiotherapy, the prognosis of patients with locally advanced or metastatic cancer is significantly poorer.Objectives. ln view of the high incidence of advanced and therefore incurable prostate cancer seen at the oncology clinic of the Department of Urology, Tygerberg Hospital, we started a prostate clinic with the aim of detecting early stage prostate cancer which is potentially curable. A secondary objective was to investigate the question whether there is a higher incidence of prostate cancer among black African men.Patients and methods. Men aged 50 - 70 years were invited by means of media communications (newspaper and radio) to attend our prostate clinic for a free physical examination, including a digital rectal examination (DRE) and serum prostate specific antigen (PSA) assay. If the DRE was clinically suspicious of malignancy and/ or the serum PSA was &gt; 4 ng/ ml, the patient was appropriately counselled and referred for transrectal ultrasound (TRUS)-guided sextant prostate biopsy.Results. In the period June 1997- September 1999 a total of 1056 men attended the prostate clinic. Biopsies were indicated in 160 cases, and were obtained in 114 (71.3%, i.e. 10.8% of the entire cohort). Prostate cancer was detected on first biopsy in 3.5% of the entire group of men (in 35.9% of those with a clinically abnormal DRE, in 41.3% of those with a serum PSA &gt; 4 ng/ ml and in 88.6% of those with an abnormal DRE and serum PSA &gt; 4 ng/ ml. In the 37 men with prostate cancer, the clinical tumour stage was T1 - 2 in 83.8% and T3- 4 in 16.2%. ln the group of patients with clinical stage T1 - 2 tumours, the treatment was watchful waiting in 62.5% of cases, radiotherapy in 20.8% and radical prostatectomy in 16.7%. Analysis of the data according to race showed that in the group of 47 black men there was a higher percentage of clinically abnormal DRE, PSA &gt; 4 .0 ng/ ml and biopsies showing malignancy, and a higher overall prostate cancer detection rate (8.5%).Conclusions. Our prostate cancer detection rate of 3.5% is slightly lower than that reported in larger studies (4.7%), which may be due to the fact that prostate biopsy was performed in only 71% of those who had an indication for biopsy. ln the men diagnosed with clinically localised prostate cancer, potentially curative treatment was given in only 37.5% of cases. This compares unfavourably with the historical cohort of men seen at our oncology clinic, where 53% received potentially curative treatment, and a large European study where potentially curative treatment was given in 89% of cases. Our finding that black men had a higher percentage of clinically abnormal DRE, PSA &gt; 4.0 ng/ ml and biopsies showing malignancy and a higher overall detection rate of prostate cancer should be interpreted with caution, since black men comprised only 4.5% of our overall study cohort.

    Long-term continuous administration of a hydro-ethanolic extract of Synedrella nodiflora (L) Gaertn in male Sprague-Dawley rats: biochemical, haematological and histopathological changes

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    Background: Conflicting reports about the toxicity of Synedrella nodiflora (L) Gaertn (family Asteraceae), a plant traditionally used in Ghana for the management of epilepsy, abound in literature. The present study evaluates the effect of a 90-day continuous oral administration of a hydro-ethanolic whole plant extract of Synedrella nodiflora (SNE) in male Sprague-Dawley rats.Methods: The toxicological evaluation of the extract (100, 300 and 1000 mgkg-1) was focused on haematological, serum biochemical parameters and histopathological changes of some isolated organs.Results: The extract produced no mortality in the rats treated during the study period. Only SNE 100 mgkg-1 produced significant decrease in white blood cell and neutrophil counts and an increase in albumin, globulin, total bilirubin, total protein and potassium levels. The higher doses (SNE 300 and 1000 mgkg-1) had no significant effect on all the haematological and biochemical parameters measured. Histopathological assessment of the liver, kidney and heart revealed no abnormalities in rats treated with the extracts. Only the SNE 1000 mgkg-1 produced distortions of the branching arrangements of the myocardial fibres and a congested vessel which indicates a healed infarction.Conclusions: The findings suggest hydro-ethanolic extract of Synedrella nodiflora (L) Gaertn generally has a low toxicity profile following a 90-day continuous oral administration in male Sprague-Dawley rats under the present laboratory conditions. However patients with renal or cardiac problems should use the plant with caution.Funding: Jointly supported by the International Foundation for Science, Stockholm, Sweden, through a grant (# F/5191-1) to Dr. Patrick Amoateng and the Office of Research, Innovation and Development (ORID), University of Ghana, Accra, Ghana, grant awarded to Dr. Patrick Amoateng (reference number: URF/6/ILG-002/2012-2013)Keywords: : Synedrella nodiflora, Sprague-Dawley rats, histopathological, haematologica

    Assessment of Heavy Metal Contamination and Distribution in Surface Soils and Plants along the West Coast of Ghana

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    Onshore oil drilling activity is ongoing at Jubilee oil fields, Ghana. This activity could lead to heavy metal exposure with consequential adverse effects on public health in nearby coastal communities. Therefore, we assessed heavy metal levels and spatial distribution in soils and plants from the west coast of Ghana to obtain baseline values for monitoring heavy metal exposure. Surface soils were collected from six coastal communities, and analyzed for arsenic, cadmium, copper, mercury, lead, selenium and zinc using atomic absorption spectrophotometer. Mean heavy metal concentrations in soil samples were 2.06, 6.55, 0.016, 21.59, 0.18 and 39.49mg/kg for arsenic, copper, mercury, lead, selenium and zinc, respectively. Mean heavy metal concentrations in plants were 2.70, 17.47, 3.17, 91.74, 1.51 and 9.88mg/kg for arsenic, cadmium, copper, lead, selenium and zinc, respectively. Concentrations of arsenic, cadmium and lead in plants exceeded WHO/FAO permissible limits. Enrichment factor for arsenic was significant and extremely high for selenium, while geoaccumulation index showed moderate pollution for selenium. Soil contamination factors for arsenic, lead, and selenium indicated considerable contamination. In view of these findings remediation methods must be adopted to safeguard the communities. The data will be useful for future monitoring of heavy metal exposure in the communities and to assess the impact of the ongoing crude oil drilling activity on the environment

    Measuring Strategic Uncertainty in Coordination Games

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    Lecture on the first SFB/TR 15 meeting, Gummersbach, July, 18 - 20, 2004This paper explores predictability of behavior in coordination games with multiple equilibria. In a laboratory experiment we measure subjects' certainty equivalents for three coordination games and one lottery. Attitudes towards strategic uncertainty in coordination games are related to risk aversion, experience seeking, gender and age. From the distribution of certainty equivalents among participating students we estimate probabilities for successful coordination in a wide range of coordination games. For many games success of coordination is predictable with a reasonable error rate. The best response of a risk neutral player is close to the global-game solution. Comparing choices in coordination games with revealed risk aversion, we estimate subjective probabilities for successful coordination. In games with a low coordination requirement, most subjects underestimate the probability of success. In games with a high coordination requirement, most subjects overestimate this probability. Data indicate that subjects have probabilistic beliefs about success or failure of coordination rather than beliefs about individual behavior of other players

    Molecular diagnosis for the novel coronavirus SARS-CoV-2: lessons learnt from the Ghana experience

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    Background: A novel coronavirus, SARS-CoV-2 is currently causing a worldwide pandemic. The first cases of SARS-CoV-2 infection were recorded in Ghana on March 12, 2020. Since then, the country has been combatting countrywide community spread. This report describes how the Virology Department, Noguchi Memorial Institute for Medical Research (NMIMR) is supporting the Ghana Health Service (GHS) to diagnose infections with this virus in Ghana.Methods: The National Influenza Centre (NIC) in the Virology Department of the NMIMR, adopted real-time Polymerase Chain Reaction (rRT-PCR) assays for the diagnosis of the SARS-CoV-2 in January 2020. Samples from suspected cases and contact tracing across Ghana were received and processed for SARS-CoV-2. Samples were ‘pooled’ to enable simultaneous batch testing of samples without reduced sensitivity.Outcomes: From February 3 to August 21, the NMIMR processed 283 946 (10%) samples. Highest number of cases were reported in June when the GHS embarked on targeted contact tracing which led to an increase in number of samples processed daily, peaking at over 7,000 samples daily. There were several issues to overcome including rapid consumption of reagents and consumables. Testing however continued successfully due to revised procedures, additional equipment and improved pipeline of laboratory supplies. Test results are now provided within 24 to 48 hours of sample submission enabling more effective response and containment.Conclusion: Following the identification of the first cases of SARS-CoV-2infection by the NMIMR, the Institute has trained other centres and supported the ramping up of molecular testing capacity in Ghana. This provides a blueprint to enable Ghana to mitigate further epidemics and pandemics
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