99 research outputs found
Managed flood storage option for selected levees along the lower Illinois River for enhancing flood protection, agriculture, wetlands, and recreation: Second report, validation of the UNET model for the lower Illinois River
"March 1997.""A division of the Illinois Department of Natural Resources.
Rain Induced Cross Polarization on Satellite Communication in Nigeria
Microwave systems performance on satellite communication link operating above 10 GHz
is increasingly degraded by rain when designing telecommunication systems. Cross polarization
is one of the major source of signal degradation that affectthe frequency reuse when employed to
boost capacity of the channel. The effect of cross-polarization in thirty-seven (37) stations in Nigeria
were carried out using 10 years data obtained from Nigeria Meteorological Agency (NIMET) at the
look angle from Nigeria Communication Satellite (NigComSat). International Telecommunication
Union-Recommendation (ITU-R) model was used to for this study. The stations were grouped
into six geopolitical zones in Nigeria which are Southwest (SW), Southeast (SE), South-south (SS),
Northcentral (NC), Northwest (NW) and Northeast (NE). The results reveal that cross-polarization
discrimination (XPD) become very poor as frequency (at Ku-band, Ka-band, V-band) increases
especially at lower percentage of time (such as 0.001%, and 0.01%) unavailability. Hence XPD,
at all frequencies is poorer in the southern part of Nigeria SE, SS and SW due to high rainfall rate.
The results also show that only Northern part of the country will experience no interference at 0.01%
as XPD is over 30 dB ITU-R base line for Ku-band transmission. However, for Ka-band and V-band
at 0.001% and 0.01% unavailability of time interference will occur in all stations in Nigeria, but at
0.1% and 1% XPD is over 30 dB for all stations. This study will help in the adequate planning and
designing of satellite telecommunication expansion in all the six geopolitical zones in Nigeria
Bt maize for small scale farmers: A case study
The role of biotechnology in small holder agricultural systems has been the subject of much debate in South Africa and the Southern African Development Community (SADC) region as a whole. The debate has centered on the suitability of biotechnology crops in small holder agricultural systems. In South Africa, genetically modified (GM) white maize was approved for commercial production in 1998. To educate and inform small-scale farmers and to give them the opportunity to evaluate GM white maize for themselves, six demonstration plots were planted at strategic locations. This communications presents the results obtained from these six demonstration plots. In all plots it was found that GM maize gave higher yields and had less stalk borer damage than the comparable non GM variety. GM white maize can be beneficial to small scale farmers located in areas where maize stalk borer is a majorproduction factor. However, it is important that the authorities provide an effective extension service and financial support in order that the full potential of GM white maize can be experienced
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Factors Associated With Pulmonary Tuberculosis-HIV Co-Infection in Treatment-Naive Adults in Jos, North Central Nigeria
Background: Co-infection with tuberculosis and human immunodeficiency virus (TB-HIV) remains a major global health problem, with about 1.1 million new cases of TB in HIV-positive persons reported in 2011; 79% of the reported cases were amongst patients living in Africa. Advanced immune suppression remains the most important risk factor for tuberculosis in those with HIV, but epidemiological and clinical factors have also been identified. We sought to determine the prevalence and factors associated with pulmonary tuberculosis (PTB) in antiretroviral therapy (ART)- naive HIV-infected patients seeking HIV care services at a tertiary health facility in North Central Nigeria. Methods: We compared clinical and laboratory data for 218 HIV-1 positive adults with and without a diagnosis of pulmonary tuberculosis. Results from univariate analyses informed the selection of predictors to conduct multivariate analysis to determine which factors were associated with presence of PTB-HIV co-infection. Results: The prevalence of PTB-HIV co-infection in the evaluated cohort was 9.6%. Lower CD4+ cell count and the presence of oropharyngeal candidiasis were independently associated with PTB-HIV co-infection. CD4+ cell count was strongly associated with PTB-HIV co-infection (p=0.002) with the odds of co-infection reduced by 85% in those with a CD4+ cell count >100 cells/mm3 compared to those with <100 cells/ mm3. There was a strong association between oropharyngeal candidiasis and PTB-HIV co-infection, where the odds of co-infection are about 4.5 times higher in those with oropharyngeal candidiasis than those without candidiasis (p=0.008). Conclusion: PTB was prevalent among HIV patients seeking care in our setting. Severe immune suppression and oropharyngeal candidiasis were associated with PTB-HIV co-infection in our patients at presentation. Potential implications for severe immune suppression and advanced HIV disease are a poor clinical outcome and further spread of PTB. Strategies to encourage the early diagnosis of both HIV and TB should be considere
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Genetic Determinants of Drug-Resistant Tuberculosis among HIV-Infected Patients in Nigeria
Tuberculosis (TB) is the most common opportunistic infection in human immunodeficiency virus (HIV)-infected patients and the emergence of drug-resistant tuberculosis (DR-TB) is a growing problem in resource-limited settings. Adequate infrastructure for testing drug sensitivity and sufficient evidence of first-line resistance are currently unavailable in Nigeria. We collected sputum samples from HIV-infected patients enrolled in the Harvard PEPFAR/APIN Plus program over 12 months at two PEPFAR antiretroviral therapy (ART) clinics in the southwest and north central regions in Nigeria. Smear-positive sputum samples were submitted for GenoType MTBDRplus testing (n = 415); mutations were confirmed through sequencing. Our results show high rates of DR-TB in Nigerian HIV-infected individuals (7.0% for rifampin [RIF] and 9.3% for RIF or isoniazid [INH]). Total RIF resistance indicative of MDR-TB in treatment-naive patients was 5.52%, far exceeding the World Health Organization predictions (0 to 4.3%). RIF resistance was found in 6/213 (2.8%) cases, INH resistance was found in 3/215 (1.4%) cases, and MDR-TB was found in 8/223 (3.6%) cases. We found significantly different amounts of DR-TB by location (18.18% in the south of the country versus 3.91% in the north central region [P < 0.01]). Furthermore, RIF resistance was genetically distinct, suggesting possible location-specific strains are responsible for the transmission of drug resistance (P < 0.04). Finally, GenoType MTBDRplus correctly identified the drug-resistant samples compared to sequencing in 96.8% of cases. We found that total DR-TB in HIV-infection is high and that transmission of drug-resistant TB in HIV-infected patients in Nigeria is higher than predicted
Intermittent preventive treatment with sulphadoxine-pyrimethamine is effective in preventing maternal and placental malaria in Ibadan, south-western Nigeria
<p>Abstract</p> <p>Background</p> <p>Intermittent preventive treatment with sulphadoxine-pyrimethamine (IPT-SP) is currently the recommended regimen for prevention of malaria in pregnancy in endemic areas. This study sets out to evaluate the effectiveness of IPT-SP in the prevention of maternal and placental malaria in parturient mothers in Ibadan, Nigeria, where the risk of malaria is present all year round.</p> <p>Method</p> <p>During a larger study evaluating the epidemiology of congenital malaria, the effect of malaria prophylaxis was examined in 983 parturient mothers. Five hundred and ninety eight mothers (60.8%) received IPT-SP, 214 (21.8%) received pyrimethamine (PYR) and 171 (17.4%) did not take any chemoprophylactic agent (NC).</p> <p>Results</p> <p>The prevalence of maternal parasitaemia in the IPT-SP, PYR and NC groups was 10.4%, 15.9% and 17% respectively (p = 0.021). The prevalence of placental parasitaemia was 10.5% in the IPT-SP, 16.8% PYR and 17% NC groups, respectively (p = 0.015). The prevalence of maternal anaemia (haematocrit <30%) was 5.7% vs. 8.9% vs. 13.4% among the IPT-SP, PYR and NC groups respectively (p < 0.0001) while that of pre-term delivery (GA <37 weeks) was 10.5%, 19.2% and 25.3% among IPT-SP, PYR and NC groups respectively (p < 0.0001). Babies born to mothers in the IPT-SP, PYR and NC groups had mean birth weights of 3204 ± 487.16, 3075 ± 513.24 and 3074 ± 505.92 respectively (Ï < 0.0001). There was a trend towards a lower proportion of low birth weight babies in the IPT-SP group (p = 0.095).</p> <p>Conclusion</p> <p>IPT-SP is effective in preventing maternal and placental malaria as well as improving pregnancy outcomes among parturient women in Ibadan, Nigeria. The implementation of the recently adopted IPT-SP strategy should be pursued with vigour as it holds great promise for reducing the burden of malaria in pregnancy in Nigeria.</p
Enzyme immobilisation on amino-functionalised multi-walled carbon nanotubes : structural and biocatalytic characterisation
BACKGROUND: The aim of this work is to investigate the structure and function of enzymes immobilised on nanomaterials. This work will allow better understanding of enzyme-nanomaterial interactions, as well as designing functional protein-nanomaterial conjugates. METHODOLOGY/PRINCIPAL FINDINGS: Multiwalled carbon nanotubes (MWNTs) were functionalised with amino groups to improve solubility and biocompatibility. The pristine and functionalised forms of MWNTs were characterised with Fourier-transform infrared spectroscopy. Thermogravimetric analysis was done to examine the degree of the functionalisation process. An immobilised biocatalyst was prepared on functionalised nanomaterial by covalent binding. Thermomyces lanuginosus lipase was used as a model enzyme. The structural change of the immobilised and free lipases were characterised with transmission electron Microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy and Circular dichroism spectroscopy. Biochemical characterisation of immobilised enzyme showed broader pH and thermal optima compared to soluble form. Reusability of the immobilised enzyme for hydrolysis of long chain esters was demonstrated up to ten cycles. CONCLUSION/SIGNIFICANCE: Lipase immobilised on MWNTs has exhibited significantly improved thermal stability. The exploration of advanced nanomaterial for enzyme immobilisation support using sophisticated techniques makes nanobiocatalyst of potential interest for biosensor applications
Differential induction of malaria liver pathology in mice infected with Plasmodium chabaudi AS or Plasmodium berghei NK65
Efficacy of Major Plant Extracts/Molecules on Field Insect Pests
Insect pests are considered the major hurdle in enhancing the production and productivity of any farming system. The use of conventional synthetic pesticides has led to the emergence of pesticide-resistant insects, environmental pollution, and negative effects on natural enemies, which have caused an ecological imbalance of the predator-prey ratio and human health hazards; therefore, eco-friendly alternative strategies are required. The plant kingdom, a rich repertoire of secondary metabolites, can be tapped as an alternative for insect pest management strategies. A number of plants have been documented to have insecticidal properties against various orders of insects in vitro by acting as antifeedants, repellents, sterilant and oviposition deterrents, etc. However, only a few plant compounds are applicable at the field level or presently commercialised. Here, we have provided an overview of the broad-spectrum insecticidal activity of plant compounds from neem, Annona, Pongamia, and Jatropha. Additionally, the impact of medicinal plants, herbs, spices, and essential oils has been reviewed briefl
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