48 research outputs found

    Insecticide resistance and the future of malaria control in Zambia.

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    BACKGROUND: In line with the Global trend to improve malaria control efforts a major campaign of insecticide treated net distribution was initiated in 1999 and indoor residual spraying with DDT or pyrethroids was reintroduced in 2000 in Zambia. In 2006, these efforts were strengthened by the President's Malaria Initiative. This manuscript reports on the monitoring and evaluation of these activities and the potential impact of emerging insecticide resistance on disease transmission. METHODS: Mosquitoes were captured daily through a series of 108 window exit traps located at 18 sentinel sites. Specimens were identified to species and analyzed for sporozoites. Adult Anopheles mosquitoes were collected resting indoors and larva collected in breeding sites were reared to F1 and F0 generations in the lab and tested for insecticide resistance following the standard WHO susceptibility assay protocol. Annual cross sectional household parasite surveys were carried out to monitor the impact of the control programme on prevalence of Plasmodium falciparum in children aged 1 to 14 years. RESULTS: A total of 619 Anopheles gambiae s.l. and 228 Anopheles funestus s.l. were captured from window exit traps throughout the period, of which 203 were An. gambiae malaria vectors and 14 An. funestus s.s.. In 2010 resistance to DDT and the pyrethroids deltamethrin, lambda-cyhalothrin and permethrin was detected in both An. gambiae s.s. and An. funestus s.s.. No sporozoites were detected in either species. Prevalence of P. falciparum in the sentinel sites remained below 10% throughout the study period. CONCLUSION: Both An. gambiae s.s. and An. funestus s.s. were controlled effectively with the ITN and IRS programme in Zambia, maintaining a reduced disease transmission and burden. However, the discovery of DDT and pyrethroid resistance in the country threatens the sustainability of the vector control programme

    Drivers of Change or Cut-Throat Competitors? Challenging Cultures of Innovation of Chinese and Nigerian Migrant Entrepreneurs in West Africa

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    L'afflux remarquable des entrepreneurs migrants chinois dans différents pays d'Afrique occidentale au cours des dernières années a été heurtée à une résistance de plus en plus farouche par des entrepreneurs locaux établis. Que le premiers ont un avantage concurrentiel sur ce dernier en raison de traits socio-culturels distinctifs, ou si l'efficacité supposée chinoise est juste une caractéristique de toutes les diasporas mercantiles, est ouvert à la question. Cette étude exploratoire des migrants entrepreneuriales chinois et nigérians au Ghana et au Bénin tente de répondre à cette question. Apparemment, les forces culturels des agents du changement migrants ne sont pas limités à des systèmes de valeurs héritées ou religions, comme une éthique protestante ou le confucianisme, mais ils sont adaptés en permanence et ont inventé de nouveau par des réseaux transnationaux de la migration dans un monde globalisé. Il n'y a aucune preuve d'une prétendue supériorité de la culture d’innovation chinois par rapport aux cultures d’innovation africains des migrants entrepreneuriales. Plutôt, il existe une capacité accrue d'innovation d'une diaspora mercantile en général vis à vis des entrepreneurs locaux, indépendamment de l'origine de la culture nationale dans lequel il est intégré. En outre, la rivalité des entrepreneurs migrants chinois et nigérians dans les marchés africains ne conduit pas nécessairement à la concurrence coupe-gorge souvent suspectée sous l'impact de la mondialisation. Souvent, les deux groupes agissent plutôt complémentaires. Cela contribue, sous certaines conditions, même à la réduction de la pauvreté dans le pays d'accueil

    First candidates for γ vibrational bands built on the [505] 11/2− neutron orbital in odd-A Dy isotopes:

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    Rotational structures have been measured using the Jurogam II and GAMMASPHERE arrays at low spin following the 155Gd(α,2n)157Dy and 148Nd(12C,5n)155Dy reactions at 25 and 65 MeV, respectively. We report high-K bands, which are conjectured to be the first candidates of a Kπ=2+γ vibrational band, built on the [505]11/2− neutron orbital, in both odd-A155,157Dy isotopes. The coupling of the first excited K=0+ states or the so-called β vibrational bands at 661 and 676 keV in 154Dy and 156Dy to the [505]11/2− orbital, to produce a Kπ=11/2− band, was not observed in both 155Dy and 157Dy, respectively. The implication of these findings on the interpretation of the first excited 0+ states in the core nuclei 154Dy and 156Dy are also discussed

    p17 from HIV induces brain endothelial cell angiogenesis through EGFR-1-mediated cell signalling activation

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    © 2018, United States & Canadian Academy of Pathology. HIV-associated neurocognitive disorder in HIV patients substantially reduces their quality of life. We previously showed that the HIV matrix protein, p17 could stimulate lymph-angiogenesis in vitro potentially contributing to lymphoma tumour growth and in addition is associated with vascular activation in neuro-degenerating brain tissue; here, therefore, we have investigated the detailed molecular mechanisms of this action. We performed in vitro cell culture, angiogenesis experiments, phospho-protein microarrays and Western blotting to identify cellular signalling induced by p17 within human brain endothelial cells (HbMEC), and inhibitor studies to block p17-induced vascular growth. We also characterised the effects of hippocampal CA1 injection of p17 on epidermal growth factor receptor-1 (EGFR1) expression linked to our murine model of dementia. p17 strongly induced angiogenesis of HbMEC (migration, tube formation and spheroid growth). p17 concomitantly increased phosphorylation of EGFR1 as well as down-stream intermediates ERK1/2, FAK, PLC-γ and PKC-β whilst an inhibitor peptide of EGFR, blocked cell signalling and angiogenesis. Finally, Mice that showed reduced cognitive function and behavioural deficiencies after p17 injection, demonstrated that p17 localised in cortical microvessels and also neurones many of which stained positive for p-EGFR1 by histology/IHC. This work provides strong support that p17 may be involved in initiating and/or perpetuating vascular tissue pathophysiology associated with comorbidity in HIV patients

    Aid on Demand: African Leaders and the Geography of China's Foreign Assistance

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    Characterization of ultra low frequency (ULF) pulsations and the investigation of their possible source

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    In this paper we present the results from the observation of ultra low frequency (ULF) pulsations in the Doppler velocity data from SuperDARN HF radar located at Goose Bay (61.94° N, 23.02° E, geomagnetic). Fourier spectral techniques were used to determine the spectral content of the data and the results show Pc 5 ULF pulsations (with a frequency range of 1 to 4 mHz) where the magnetic field lines were oscillating at discrete frequencies of about 1.3 and 1.9 mHz. These pulsations are classified as field lines resonance (FLR) since the 1.9 mHz component exhibited an enhancement in amplitude with an associated phase change of approximately 180° across a resonance latitude of 71.3°. The spatial and temporal structure of the ULF pulsations was examined by investigating their instantaneous amplitude which was calculated as the amplitude of the analytic signal. The results presented a full field of view which exhibit pulsations activity simultaneously from all beams. This representation shows that the peak amplitude of the 1.9 mHz component was observed over the longitudinal range of 13°. The temporal structure of the pulsations was investigated from the evolution of the 1.9 mHz component and the results showed that the ULF pulsations had a duration of about 1 h. Wavelet analysis was used to investigate solar wind as a probable source of the observed ULF pulsations. The time delay compared well with the solar wind travel time estimates and the results suggest a possible link between the solar wind and the observed pulsations. The sudden change in dynamic pressure also proved to be a possible source of the observed ULF pulsations

    Detrimental Effects of Lipid Peroxidation in Type 2 Diabetes: Exploring the Neutralizing Influence of Antioxidants

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    Lipid peroxidation, including its prominent byproducts such as malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE), has long been linked with worsened metabolic health in patients with type 2 diabetes (T2D). In fact, patients with T2D already display increased levels of lipids in circulation, including low-density lipoprotein-cholesterol and triglycerides, which are easily attacked by reactive oxygen molecules to give rise to lipid peroxidation. This process severely depletes intracellular antioxidants to cause excess generation of oxidative stress. This consequence mainly drives poor glycemic control and metabolic complications that are implicated in the development of cardiovascular disease. The current review explores the pathological relevance of elevated lipid peroxidation products in T2D, especially highlighting their potential role as biomarkers and therapeutic targets in disease severity. In addition, we briefly explain the implication of some prominent antioxidant enzymes/factors involved in the blockade of lipid peroxidation, including termination reactions that involve the effect of antioxidants, such as catalase, coenzyme Q10, glutathione peroxidase, and superoxide dismutase, as well as vitamins C and E

    Proportional crosstalk for the iThemba LABS clover detector

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    CITATION: Noncolela, S.P. et al. 2017. Proportional crosstalk for the iThemba LABS clover detector. Acta Physica Polonica B, 48(3):347-350, doi:10.5506/APhysPolB.48.347.The original publication is available at http://www.actaphys.uj.edu.pl/Measurements of the proportional crosstalk were performed for the iThemba LABS segmented clover detector. More than 1000 crosstalk parameters were determined and a crosstalk correction algorithm was implemented successfully.Publishers versio
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