190 research outputs found

    Green Synthetic Methods for a Schiff Base from 2-Aminopyridine and 4-Ethoxybenzaldehyde

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    The novel Schiff base was acquired from the reaction between 2-aminopyridine and 4-ethoxybenzaldehyde using three (3) techniques; refluxing in ethanol for 2 hours, stirring in ethanol and an ethanol-water (1:1) mixture at room temperature for an hour. The synthesis of the 2-aminopyridine-4-ethoxybenzaldehyde Schiff base produced dark yellow crystals with melting point range of 95-97oC. The reaction in ethanol under reflux produced the highest yield of 88.2% while the reaction in ethanol and ethanol-water (1:1 v/v) mixture at room temperature gave 69.2% and 43.5% yield of the compound respectively. The IR spectrum showed the following bands; 1681cm-1 (C=N), 1595cm-1 (aromatic C=C stretch), 2981cm-1 (aromatic C-H stretch), 1509cm-1 (aromatic C=N stretch), 1155cm-1 (aliphatic C-C stretch), 1036 (aromatic C-O stretch), 2825 (aliphatic C-H stretch). The 13C NMR spectrum showed the following chemical shifts (δppm); 158.48 (C=N, imino), 154.98 and 150.18 (C-N of aromatic pyridine moiety), 121.44 – 137.53 (aromatic carbons), 158.68 (aromatic C-O), 63.88 (aliphatic C-O), 15.22 (aliphatic C). The 1H NMR spectral data (δppm) for the compound gave the following results; 7.06-7.91, m (8H) (Ar-H), 9.71, s (1H) (HC=N-), 4.10, q (2H) and 1.32, t (3H) (OCH2CH3). The spectral data was in agreement to the predicted structure of the Schiff base

    Diameter distribution of Nauclea diderrichii (D Wild) Merr. Plantations in a restricted tropical rainforest of Nigeria

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    Distribution of tree diameter in a specific stand provides basic information for forest management. Little attention is given to the use of probability distribution functions in characterising the stem diameters of most Nigeria indigenous species. This study used Three-parameters lognormal and Weibull probability distribution functions in characterising the diameter of Nauclea diderrichii plantations within a restricted tropical rainforest of Nigeria for sustainable management. Thirty temporary sample plots of dimensions 20 m × 20 m were randomly laid in three age strata (42, 43 and 46 years). Stem diameters of all living Nauclea diderrichii trees with diameter at breast height ≥10.0 cm in all the sampled plots were enumerated. The performance and suitability result revealed that lognormal distribution gave superior description of the stem diameter for the Nauclea diderrichii species in the study area, with least values of Bias (0.00001), Mean absolute error (0.1214), Mean square error (0.7421), Kolmogorov-Smirnov (0.02781) and Anderson Darling (0.49562) statistics. Hence, three-parameter lognormal using maximum likelihood method was recommended for distributing stem diameter of Nauclea diderrichii in the study area.Keywords: Indigenous species; Lognormal; Maximum likelihood; Probability distribution function; Weibul

    Seed banks as conservation tool for endangered wild plant species in ecozones of Nigeria

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    Seed banks have played the largest role in the conservation of endangered wild plant species in the world. The potential role of seed in the regeneration of plant species is threatened by a rapid decline in the longevity and viability of the seeds in their natural habitats. This study addresses the key role of seed banks in the conservation of floristic diversity. The increasing popularity of the seed bank as a tool in the conservation of wild plant species can be attributed to different significance, including; provision of immediate access to plant samples, allowing researchers and conservation biologists to evaluate them for properties such as new sources of medicines, nutrition, and genes. Also, wild plant seeds conserved in seed banks are immune to habitat destruction, diseases, and predators. The stored seeds can be used to reinstate species into existing, suitable habitats where they were once present, or to augment the diversity of small, genetically depleted populations. Conservation efforts, as sources for population reintroduction and restoration, have been cited as an important justification for seed banks. Thus, it is recommended that seed banks with state-of-the-art storage facilities should be established at the national and local levels; and all of such banks should be networked so that materials, knowledge, and expertise on particular wild plant species is available on a global scale.Key words: Conservation, Endangered, Floristic diversity, Plant species, Seeds bank, Storag

    Moringa oleifera Lam extract attenuates gastric ulcerations in high salt loaded rats

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    Moringa oleifera Lam is a plant used extensively both in traditional and orthodox medicine to treat myriad ailments, including gastrointestinal disorders. This study was carried out to investigate the effect of leaf extract of M. oleifera some gastrointestinal function parameters in high salt loaded rats. Acute toxicity study was done using 70 male white mice (18-20 g) were used for the study. They were randomly selected and assigned to 7 cages of 10 animals per cage. Percentage mortalities were converted to probits and plotted against the log10 of the dose of the extract from which the LD50 value was calculated. Fresh leaf extract of M. oleifera was Soxhlet extracted. 24 albino Wistar rats were randomly assigned into 4 main groups of 6 rats each. Fed on normal rat chow, high salt (8% NaCl) diet + 1% NaCl drinking water and/or M. oleifera extract (600 mg/kg bw). The feeding regimens lasted for 42 days. Results obtained revealed that the extract had an LD50 value of 1,872.22 mg/kg from which a test dose of 600 mg/kg was derived for the feeding regimen. The salt fed rats had significantly (p<005) raised basal gastric acid output (9.03 ± 0.17 mmol/L/hr) compared with control (7.27 ± 0.17 mmol/L/hr), but had blunted response to administered histamine and cimetidine, while treatment with the extract enhanced the sensitivity of histamine in high salt loaded rats. Gastric mucus concentration was significantly (p<0.05) higher in the salt untreated group (0.25 ± 0.004 g) compared with other groups. The salt fed untreated group also had significantly (p<0.05) raised gastric ulcers (10.83 ± 0.70) compared with other groups, these were reversed following Moringa treatment. In conclusion, Moringa oleifera extract reverses gastric ulcers and blunted histaminergic receptors in high salt fed rats. The mechanism by which high salt increases gastric secretion is independent of the histaminergic mechanism

    Protective Effect of Ethanol Extract of Annona Muricata Leaves on Hematological Profile, Histology and Oxidative Stress in 1,2-Dimethylhydrazine-induced Colorectal Carcinogenesis in Rats

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    Cancer starts when cells in the body start to grow out of control (malignant growth). Colorectal cancer starts in the colon or the rectum. Annona Muricata is a medicinal plant and is considered as a basis for health preservation and care worldwide. Colorectal cancer has reached epidemic proportions and is considered as a serious health problem, therefore treatment and cure of this disease is of great clinical importance. 1,2 dimethylhydrazine (DMH) is a potent carcinogen for colon cancer in rats. In this study, rats were randomly allocated into six groups: control, extract alone, DMH, extract and DMH together, extract before DMH, DMH before extract. DMH was injected subcutaneously at 25mg/1000g body weight once a week for 16 weeks, while the ethanol extract of Annona muricata leaves (EEAML) were administered to rats orally at 120mg/1000g. After sacrifice, colon and liver sections were dissected out for histological and some biochemical analysis. Blood was also collected in EDTA bottles for hematological assays. The group injected with DMH (subcutaneously) and orally administered leaves extract of A. Muricata simultaneously showed similar results with the rats fed with normal feed, as there was absence of polyps in the rats’ colon when compared with those injected with DMH alone for 16 weeks. Malondialdehyde level of rats injected with DMH were significantly increased (p ˂ 0.05) compared to the control. Hematology indices and caspase 3 activity show the protective effects of EEAML against DMH.

    Folate levels in children with sickle cell anaemia on folic acid supplementation in steady state and crises at a tertiary hospital in Enugu, Nigeria: a prospective, comparative study

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    IntroductionFolic acid supplementation is an integral aspect of the management of children with sickle cell anaemia (SCA) especially in Africa. In spite of this, there have been concerns about lower folate levels, especially during crisis. AimTo determine red cell folate levels of children with sickle cell anaemia in steady state and during crisis and compare with those with haemoglobin AA genotype. MethodThis study was prospective, hospital based, and comparative. Fifty children with sickle cell anaemia were recruited during crises and followed up until they met the criteria for attaining steady state. The controls were fifty children matched with those with SCA for age and gender and had haemoglobin AA genotype. Red cell folate estimation was done with the Electrochemiluminescence Immunoassay (ECLIA) method using the automated Roche Cobas e411 equipment. ResultsThe median (IQR) red cell folate level in children during sickle cell crisis was 265.95 (134.50) ng/ml, which was significantly lower than the median (IQR) of 376.30 (206.85) ng/ml obtained during steady state. Most children with SCA (41 out of 50) had significantly higher folate levels during steady state (T=1081, Z-score= -4.660, p &lt; 0.001). Median level of red cell folate was lower during anaemic crisis compared to vaso-occlusive crisis, though not significantly so (N(50), U = 214.00, Z-score= -1.077, p = 0.305). The median red cell folate level of normal controls was 343.55 (92.90) ng/ml, which was significantly lower than the 376.30 (206.85) ng/ml obtained during steady state (N(50), U= 209.00, Z-score= -7.177, p &lt;0.001). Conclusion Median red cell folate levels of the study participants were within normal limits, though most children with SCA had significantly higher levels during steady state compared to crisis. Normal controls had significantly lower red cell folate levels than the children with SCA during steady state

    Histological staining properties of Khaya senegalensis wood dust extracts: a preliminary study

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    Crude aqueous and methanol extracts of Khaya senegalensis wood dust were employed as histological stains for the demonstration of general tissue architecture. Preliminary phytochemical screening of the extracts was conducted. Mixtures of the extracts of K. senegalensis in acidic, alkaline and neutral solutions were used to stain tissue sections. Preliminary phytochemical screening revealed that K. senegalensis extracts contains flavonoids, saponins, tannins, glycosides and reducing sugars. Optimum staining time was 15 minutes for both extracts and they stained the tissues in different shades of red and brown in the various media used. The best and worst stain uptake of tissues was observed with both extracts in alkaline and neutral media respectively. Mordant preparation of the extracts produced no significant staining difference from the non-mordant preparations. Staining solutions of the extracts have better affinity for the cellular cytoplasm and hence gave a good contrast when compared with Hematoxylin and Eosin control sections. In conclusion, Khaya senegalensis wood extract is a promising histological stain for the demonstration of general tissue architecture.Keywords: Khaya senegalensis, wood dust, stain, histology, mordan

    Exposure of African ape sites to climate change impacts

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    Large gaps remain in our understanding of the vulnerability of specific animal taxa and regions to climate change, especially regarding extreme climate impact events. Here, we assess African apes, flagship and highly important umbrella species for sympatric biodiversity. We estimated past (1981–2010) and future exposure to climate change impacts across 363 sites in Africa for RCP2.6 and RCP6.0 for near term (2021–2050) and long term (2071–2099). We used fully harmonized climate data and data on extreme climate impact events from the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP). Historic data show that 171 sites had positive temperature anomalies for at least nine of the past ten years with the strongest anomalies (up to 0.56°C) estimated for eastern chimpanzees. Climate projections suggest that temperatures will increase across all sites, while precipitation changes are more heterogeneous. We estimated a future increase in heavy precipitation events for 288 sites, and an increase in the number of consecutive dry days by up to 20 days per year (maximum increase estimated for eastern gorillas). All sites will be frequently exposed to wildfires and crop failures in the future, and the latter could impact apes indirectly through increased deforestation. 84% of sites are projected to be exposed to heatwaves and 78% of sites to river floods. Tropical cyclones and droughts were only projected for individual sites in western and central Africa. We further compiled available evidence on how climate change impacts could affect apes, for example, through heat stress and dehydration, a reduction in water sources and fruit trees, and reduced physiological performance, body condition, fertility, and survival. To support necessary research on the sensitivity and adaptability of African apes to climate change impacts, and the planning and implementation of conservation measures, we provide detailed results for each ape site on the open-access platform A.P.E.S. Wiki

    Corrigendum to “Counting adolescents in: the development of an adolescent health indicator framework for population-based settings”

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    The authors were recently made aware of an oversight such that parts of the text in the Introduction and Methods sections, which describe shortcomings in the existing literature and the methods in this work to identify frameworks and indicators, were missing attribution to published work cited elsewhere in the manuscript. To clarify, we adjust the relevant sections to fully attribute the prior work in three areas, as described below. Underlined text is additional to the original: While both school- and community-based modalities can provide nationally representative data among eligible adolescents, several shortcomings in adolescent health measurement in LMICs were noted by the GAMA Advisory Group (Reference 13 as in the original paper). First, these measurements do not equally cover all adolescent subgroups, with evidence gaps being largest for males, younger adolescents aged 10–14 years, adolescents of diverse genders, ethnicities, and religions, as well as those out of school and migrants. Second, age-disaggregated data are often lacking—due in part to incomplete age coverage—limiting their use for program planning. Third, several aspects of adolescent health are inadequately covered including mental health, substance use, injury, sexual and reproductive health among unmarried adolescents, and positive aspects of adolescent health and well-being. Fourth, the definitions and assessment methods used across adolescent health indicator frameworks are inconsistent. For example, adolescent overweight and obesity—a major cause of non-communicable diseases and a public health risk for future and intergeneration health—is inconsistently captured across indicator frameworks and strikingly absent from the SDGs (Reference 13 as in the original paper). Additional shortcomings include, current adolescent health data systems often lack intersectoral coordination beyond health (e.g., with education, water and sanitation, and social protection systems) and suffer from irregularities in coverage and timing (Reference 6 as in the original paper). Broadly, these indicator frameworks and strategy documents captured disease burden, health risks, and prominent social determinants of health during adolescence. To be congruent with the existing global recommendations and guidelines (References 3–7 as in the original paper) and global measurement efforts (References 10 and 16 as in the original paper), the indicator framework documents had to meet three inclusion criteria, as laid out by the GAMA Advisory Group (Reference 14 as in the original paper): (1) provide recommendations about the measurement of adolescents' health and well-being; (2) include indicators for “adolescents” covering the adolescent age range (10–19 years) in the whole or part; and (3) be global or regional in scope. Using the GAMA's approach (Reference 13 as in the original paper), the recommendations of Lancet Adolescent Health Commission (Reference 6 as in the original paper), and several other guidelines (References 7, 9, 12, 17–19 as in the original paper), we selected adolescent health and well-being domains based on four key aspects of adolescents in LMICs: a) population trends; b) disease burden; c) drivers of health inequality; and d) opportunity for interventions

    Counting adolescents in: the development of an adolescent health indicator framework for population-based settings

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    Changing realities in low- and middle-income countries (LMICs) in terms of inequalities, urbanization, globalization, migration, and economic adversity shape adolescent development and health, as well as successful transitions between adolescence and young adulthood. It is estimated that 90% of adolescents live in LMICs in 2019, but inadequate data exist to inform evidence-based and concerted policies and programs tailored to address the distinctive developmental and health needs of adolescents. Population-based data surveillance such as Health and Demographic Surveillance Systems (HDSS) and school-based surveys provide access to a well-defined population and provide cost-effective opportunities to fill in data gaps about adolescent health and well-being by collecting population-representative longitudinal data. The Africa Research Implementation Science and Education (ARISE) Network, therefore, systematically developed adolescent health and well-being indicators and a questionnaire for measuring these indicators that can be used in population-based LMIC settings. We conducted a multistage collaborative and iterative process led by network members alongside consultation with health-domain and adolescent health experts globally. Seven key domains emerged from this process: socio-demographics, health awareness and behaviors; nutrition; mental health; sexual and reproductive health; substance use; and healthcare utilization. For each domain, we generated a clear definition; rationale for inclusion; sub-domain descriptions, and a set of questions for measurement. The ARISE Network will implement the questionnaire longitudinally (i.e., at two time-points one year apart) at ten sites in seven countries in sub-Saharan Africa and two countries in Asia. Integrating the questionnaire within established population-based data collection platforms such as HDSS and school settings can provide measured experiences of young people to inform policy and program planning and evaluation in LMICs and improve adolescent health and well-being
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