54 research outputs found

    A Six-Step Continuous Multistep Method For The Solution Of General Fourth Order Initial Value Problems Of Ordinary Differential Equations

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    In this paper, continuous Linear Multistep Method (LMM) for the direct solution of fourth order initial value problems in ordinary differential equation is derived. The study provides the use of both collocation and interpolation techniques to obtain the schemes. Direct form of power series is used as basis function for approximation. An order six symmetric and zero-stable method is obtained. To implement our method, predictors of the same order of accuracy as the main method were developed using Taylor’s series algorithm.  This implementation strategy is found to be efficient and more accurate as the result has shown in the numerical experiments. The result obtained confirmed the superiority of our method over existing schemes Keywords: Direct method; Fourth order; interpolation; collocation multistep methods,;power series; approximate solutions

    Syncytiotrophoblast Extracellular Vesicles from Late-Onset Preeclampsia Placentae suppress Pro-Inflammatory immune response in THP-1 Macrophages

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    © 2021 Awoyemi, Motta-Mejia, Zhang, Kouser, White, Kandzija, Alhamlan, Cribbs, Tannetta, Mazey, Redman, Kishore and Vatish. Syncytiotrophoblast derived Extracellular Vesicles (STBEV) from normal pregnancy (NP) have previously been shown to interact with circulating monocytes and B cells, and induce pro-inflammatory cytokine release. Early-onset preeclampsia (EOPE) is associated with an exacerbated inflammatory response, yet there is little data regarding late-onset PE (LOPE) and immune function. Here, using a macrophage/monocyte cell line THP-1, we investigated the inflammatory potential of STBEV, comprising medium/large-STBEV (>200nm) and small-STBEV (<200nm), isolated from LOPE (n=6) and normal (NP) (n=6) placentae via dual-lobe ex-vivo placental perfusion and differential centrifugation. THP-1 cells bound and internalised STBEV isolated from NP and LOPE placentae, as revealed by flow cytometry, confocal microscopy and ELISA. STBEV-treated THP-1 cells were examined for cytokine gene expression by RT-qPCR and the cell culture media examined for secreted cytokines/chemokines. As has been previously reported, NP medium/large-STBEV significantly upregulated the transcriptional expression of TNF-α, IL-10, IL-6, IL-12, IL-8 and TGF-β compared to PE medium/large-STBEV, however, there was no significant difference in the small STBEV population between the two groups though in general, NP small STBEVs slightly upregulated the same cytokines. In contrast, LOPE STBEV (medium and large) did not induce pro-inflammatory responses by differentiated THP-1 macrophages. This decreased effect of LOPE STBEV was echoed in cytokine/chemokine release. Our results appear to suggest that STBEV from LOPE placentae do not have a major immune-modulatory effect on macrophages. In contrast, NP STBEV caused THP-1 cells to release pro-inflammatory cytokines. Thus, syncytiotrophoblast extracellular vesicles from LOPE dampen immune functions of THP-1 macrophages, suggesting an alternative mechanism leading to the pro-inflammatory environment observed in LOPE

    Prevalence and Predictors of Tuberculosis Coinfection among HIV-Seropositive Patients Attending the Aminu Kano Teaching Hospital, Northern Nigeria

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    Background: The HIV/AIDS epidemic has been accompanied by a severe epidemic of tuberculosis (TB), although the prevalence of coinfection is largely unknown, especially in developing countries, including Nigeria. The aim of this study was to determine the prevalence and predictors of TB coinfection among HIV-seropositive Nigerians. Methods: The case files of HIV/AIDS patients attending Aminu Kano Teaching Hospital, Nigeria from January to December 2006 were reviewed. Results: A total of 1320 HIV/AIDS patients had complete records and were reviewed, among which 138 (10.5%) were coinfected with TB (95% CI, 8.9% to 12.2%). Pulmonary TB was diagnosed in 103 (74.6%) patients, among whom only 18 (17.5%) were sputum-positive. Fifty (36.2%) coinfected patients had some type of extrapulmonary TB (EPTB); 15 had both pulmonary TB and EPTB. Among the 35 patients with EPTB only, 20 (57.1%) had abdominal TB, 5 (14.3%) had TB adenitis, 5 (14.3%) had spinal TB, 3 (8.6%) were being monitored for tuberculous meningitis, and 1 (2.9%) each had renal TB and tuberculous adrenalitis. The highest prevalence of TB, 13.7% (n = 28), was seen among patients aged 41–50 years. TB coinfection was significantly associated with marital status, WHO clinical stage, and CD4 count. Marital status (OR, 2.1; 95% CI, 1.28–3.59; P = 0.04), WHO clinical stage at presentation (4.81; 1.42–8.34; P = 0.001), and baseline CD4 count (2.71; 1.51–6.21; P = 0.02) remained significant predictors after adjustment for confounding. Conclusions: The moderately high prevalence of TB among HIV-seropositive patients underscores the urgent need for strategies that lead to rapid identification and treatment of coinfection with active or latent TB

    Effects of preboiling on the acidity and strength properties of heat-treated wood

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    Heat treatment is an alternative to the chemical treatment in wood preservation, which has been used to some extent in improving timber quality. However, reduction in strength properties has been one of the major limitations in the use of this technique and therefore investigations on the use of various pre-treatment methods are highly essential. Wood samples from Scots pine were immersed in already boiling water (100°C) for 20 min followed by 2 h of heat treatment at 160 and 200°C. The acidity and strength properties were determined by measurement of pH and static bending test, respectively. There were no significant changes in pH due to preboiling in both heat-treated and untreated wood. Similarly, preboiling did not result in any appreciable differences in strength both before heat treatment and during heat treatment at 160°C. However, for 200°C heat treatment preboiling reduced significantly the degree of strength loss as indicated by 19.4% reduction in modulus of rupture in preboiled wood compared to 26.6% reduction in unpreboiled wood. From the results of this study it is evident that preboiling has a buffering effect on wood during heat treatment and the higher the intensity of heat treatment the higher the significance of the buffering effect of pre-boiling

    International Journal of Physical Sciences

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    A four-point fully implicit method for the numerical integration of third-order ordinary differential equation

    Exposure to pesticides and zoonoses during procurement, trade, and consumption of vulture parts: an unexplored threat to human health.

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    Background: Examination into the origin of SARS-CoV-2 has shed further light on opportunities for broader zoonotic pathogen transmission stemming from the trade in living wildlife and animal parts, and in associated practices. In certain parts of the world (e.g., Africa), various bird species are illegally captured for both subsistence and non-subsistence purposes such as for belief-based use. The latter practice includes rare and declining vulture species and arises from the (relatively recent) belief that directly ingesting certain vulture body parts may impart powers of clairvoyance or bring good fortune. Among a variety of capture methods used by hunters, pesticide-poisoned or nicotine-laced baits are prevalent. In 2020, a mass mortality incident in Guinea Bissau involving over 2000 Critically Endangered Hooded Vultures was linked to belief-based practices, and to the use of a carbamate pesticide. This was to date the highest reported number of vultures killed by pesticide poisoning within a single event. Such deliberate, indiscriminate poisoning is now widely acknowledged within conservation sectors as posing evident threats to vulture species and populations. However, the potential human health repercussions arising from the possibility for zoonotic pathogen transmission (e.g., anthrax, avian H5N1 influenza), and for secondary exposure to the range of toxic substances used to capture and prepare individual birds – whether to hunters, procurers and traders of vulture parts or to consumers – have remained unexplored.Objectives: Our aims are to 1) generate awareness of these practice within human health risk assessment sectors; and 2) generate interest within the human health sector in examining the potential for zoonotic pathogen transmission and toxicity or poisoning risks to people that may stem from these practices.Discussion: We briefly describe human behaviours associated with this belief-driven practice as they relate to potential exposure, and issue a plea for examination of the associated health risks, in collaboration with ongoing conservation and wildlife forensics efforts
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