118 research outputs found
Effect of propolis consumption on hepatotoxicity and brain damage in male rats exposed to chlorpyrifos
This study was undertaken to determine the protective effect of propolis against the hepatotoxicity and brain damage of chlorpyrifos (CPF) in male rats. Animals were assigned to one of four groups. The first group was used as control. Groups 2, 3 and 4 were treated with 6.8 mg CPF /kg BW (1/20 LD50); 50 mg propolis/kg BW; CPF (6.8 mg CPF/kg BW) plus propolis (50 mg propolis/kg BW). Rats were orally administered their respective doses daily for 28 days. Serum transaminases, glucose, lactate dehydrogenase, total proteins, albumin, reduced glutathione, thiobarbituric acid-reactive substances, superoxide dismutase and catalase were assessed. Also, total lipid, cholesterol, triglyceride and LDL-c were assayed. Oral treatment with CPF was found to elicit significant deterioration in all the tested parameters confirming its toxicity. The injury of liver tissues after CPF-treatment was confirmed by the histological changes. Also, CPF caused significant decrease in the activity of serum and brain cholinesterase but increased glial fibrillary acidic protein-expression and cause some histological changes in the brain tissues. While, oral treatment with propolis plus CPF could antagonize CPFtoxicity. These results suggest that propolis may become a promising tool for wide use in reducing the liver and brain damage during CPF-exposure.Keywords: Chlorpyrifos, propolis, rats, lipid peroxidation, antioxidant enzymes, biochemical parametersAfrican Journal of Biotechnology Vol. 12(33), pp. 5232-524
Increased expression of T-helper cell activation markers in peripheral blood of children with atopic asthma
Background: Activated T-helper (CD4) cells have been implicated to contribute to the pathogenesis of bronchial asthma. However, the profile of circulating CD4 subsets in relation to disease activity and asthma severity is unclear.Objective: To study the dynamic changes in peripheral blood CD4 cells expressing the activation markers naïve/memory (CD45RA/CD45RO) and interleukin–2 light chain receptor (CD25) in asthmatic children during and after resolution of acute asthma attacks and to determine whether the expression of these activation markers would be of value in monitoring asthma severity and the response to glucocorticoid inhalation.Methods: Peripheral blood samples were obtained from 20 asthmatic children aged between 0.5 and 9 years (mean±SD: 4.37±2.37 years) with acute asthma attacks, 10 children with lower respiratory tract infection and 20 healthy, age-matched subjects. CD4 cells expressing CD45RA, CD45RO, CD45RA+RO+ and CD25 were analyzed by dual flow cytometry and serum IgE was measured by ELISA. In asthmatic children, the measurements were repeated after the resolution of acute attacks.Results: During acute asthma attacks, the percentages of CD45RA, CD45RO, CD45RA+RO+ and CD25 were significantly increased as compared to the control group (p<0.05 for CD45RA and <0.0001 for the other 3 subsets). After resolution of asthma attacks, a significant reduction of all subsets was noticed and the percentages of CD45RA and CD45RO decreased to normal values while those of CD45RA+RO+ and CD25 remained significantly higher than the controls (p<0.05 for each marker). Unlike healthy children and patients with acute lower respiratory infections, asthmatic children showed increased CD45RO/CD45RA ratio (>1) and a significant increase of the percentage of CD45RA+RO+. During acute asthma attacks, patients with severe persistent asthma showed the highest percentages of all T- helper subsets when compared to those with moderate or mild persistent asthma. Positive correlations were found between serum IgE levels and both CD45RO and CD25 (r = 0.962, p<0.001 and 0.882, p<0.05 respectively) during acute asthma attacks and these correlations remained significant in remission (r = 0.632, p<0.05 and 0.589, p<0.05 respectively). Glucocorticoid inhalation therapy induced a significant reduction in the percentage of CD45RO, CD45RA+RO+ and CD25.Conclusion: Peripheral blood T-helper cell activation markers are reliable indicators for monitoring disease activity and severity of asthma. The reversed ratio of memory/ naïve T-helper cells together with the presence of a clone of cells co-expressing both naive and memory surface markers feature atopic asthma from acute lower respiratory infections. Glucocorticoid inhalation therapy induces a significant inhibition of peripheral blood T-helper cell activation markers.Key words: Children, atopic asthma, T-helper cell subsets, glucocorticoid inhalation, lower respiratory infections, CD45RO, CD45RA, CD25
AN INVESTIGATION OF SHORT RANGE ELECTROMAGNETIC WAVE COMMUNICATION FOR UNDERWATER ENVIRONMENTAL MONITORING UTILISING A SENSOR NETWORK PLATFORM
Current state of the art water communications systems rely on optical and acoustic propagation. But these have underperformed in many applications. Wireless Sensor Network (WSN) using radio communication underwater is state of the art. The frequency of operation and the antenna are the big challenges that if unlocked, will present many advantages. The aim of this research is to investigate short range electromagnetic wave communication for underwater environmental monitoring utilising a sensor network platform. Theoretical study and preliminary experiments have confirmed that ISM (industrial, scientific and medical) band at 433MHz was suitable for potable and freshwater communication. Traditional antennas have been constructed, tested and modelled in a High Frequency Simulator Structure (HFSS) but were found unsuitable for use underwater. A 433MHz bowtie antenna was modelled in HFSS and shown to perform well in both air and potable water without any matching circuit. The antenna was prototyped on a printed circuit board, waterproofed and tested successfully in a tank. Furthermore to eliminate RF crosstalk, a battery powered wireless transmitter that generated a carrier signal at 433MHz, was used successfully in the laboratory tank, and during experiments that were repeated in freshwater in Liverpool Stanley Canal. This range, in excess of 5m, was large enough to combine the bowtie antenna with off the shelf, low power transceivers operating at the 433MHz, and specific sensors to form a WSN for potable and freshwater applications. The contribution to knowledge is the experimental demonstration of reliable communication at 433MHz using a broadband antenna which unlocks the potential of underwater WSN applications, including applications in water quality measurement, using radio communication
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The impact of oil and global markets on Saudi stock market predictability: A machine learning approach
Data availability:
Data available on request from the authors.JEL classification: C45; D53; G15.This study investigates the predictability power of oil prices and six international stock markets namely, China, France, UK, Germany, Japan, and the USA, on the Saudi stock market using five Machine Learning (ML) techniques and the Generalized Method of Moments (GMM). Our analysis reveals that prior to the 2006 collapse, oil exerted the least influence on the Saudi market, while the UK and Japan were the most influential stock markets. However, after the collapse, oil became the most influential factor, highlighting the strong dependence of Saudi Arabia's economic structure on oil production. This finding is particularly noteworthy given Saudi Arabia's efforts to reduce its reliance on oil through Vision 2030. We further demonstrate that China's influence on the Saudi market increased significantly after the 2006 collapse, surpassing that of the UK. This is attributable to the substantial trade between China, Japan, and Saudi Arabia, as well as the rise in Saudi foreign direct investment in China, and the decline in such investment in the UK post-collapse. Our results carry important implications for stock market investors and policymakers alike. We suggest that policymakers in Saudi Arabia should continue to diversify their economy away from oil and strengthen economic ties with emerging markets, particularly China, to reduce their vulnerability to oil price fluctuations and ensure sustainable economic growth.The authors received no financial support for the research, authorship, and/or publication of this article
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Volatility contagion between cryptocurrencies, gold and stock markets pre-and-during COVID-19: evidence using DCC-GARCH and cascade-correlation network
JEL Classification: C45; D53; E42; G10Availability of data and materials:
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.The rapid rise of Bitcoin and its increasing global adoption has raised concerns about its impact on traditional markets, particularly in periods of economic turmoil and uncertainty such as the COVID-19 pandemic. This study examines the extent of the volatility contagion from the Bitcoin market to traditional markets, focusing on gold and six major stock markets (Japan, USA, UK, China, Germany, and France) using daily data from January 2, 2011, to June 2, 2022, with 2958 daily observations. We employ DCC-GARCH, wavelet coherence, and cascade-correlation network models to analyze the relationship between Bitcoin and those markets. Our results indicate long-term volatility contagion between Bitcoin and gold and short-term contagion during periods of market turmoil and uncertainty. We also find evidence of long-term contagion between Bitcoin and the six stock markets, with short-term contagion observed in Chinese and Japanese markets during COVID-19. These results suggest a risk of uncontrollable threats from Bitcoin volatility and highlight the need for measures to prevent infection transmission to local stock markets. Hedge funds, mutual funds, and individual and institutional investors can benefit from using our findings in their risk management strategies. Our research confirms the utility of the cascade-correlation network model as an innovative method to investigate intermarket contagion across diverse conditions. It holds significant implications for stock market investors and policymakers, providing evidence for potentially using cryptocurrencies for hedging, for diversification, or as a safe haven.Brunel Research Initiative and Enterprise Fund to FD
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Technical efficiency in banks: a review of methods, recent innovations and future research agenda
JEL Classification: G21 · D20Copyright © The Author(s) 2023. Technical efficiency in banking is a critical aspect of the financial industry and has been widely studied using various measurement techniques. This systematic literature review offers a comprehensive examination of 305 studies on the application of technical efficiency measurement techniques in both Islamic and conventional banking sectors from 1989 to 2019. Our comprehensive analysis not only provides a broad view of the efficiency measurement literature but also outlines a future research agenda. Despite the extensive research in this field, several issues remain unresolved, including input–output selection, a comparison of efficiency between Islamic and conventional banks, limited cross-country studies, and a lack of exploration into the impact of regulation and Shariah principles. To address these gaps, this review highlights the most commonly used methods, variables, and findings and provides three key recommendations for future research. Three key themes emerge from our examination. First, there is a need to better understand and the application of new frontier techniques other than the traditional methods, which currently dominate the existing literature. Second, the intermediation approach is the most frequently used in variable selection, thus more studies with comparative findings with applications of production and value-added approaches are suggested. Third, the most frequently used input variables are ‘labor’, ‘deposits’ and ‘capital’, whilst ‘loans’ and ‘other earning assets’ are the most popular output variables. We recommend three vital directions for future research: (i) non-interest expenses to be included amongst the inputs, while non-interest income should be added to the list of outputs, especially when estimating efficiency scores of Islamic banks. (ii) The impact of environmental variables such as, inter alia, Shariah principles, country-specific factors, and management quality is suggested to be considered simultaneously in models measuring and comparing the efficiency of Islamic and conventional banks. (iii) The selection of performance metrics employed should be expanded to include both the standard efficiency scores and the Malmquist Total Factor Productivity Index (TFP). The paper concludes with research needs and suggests directions for future research
Haptoglobin and Sickle Cell Polymorphisms and Risk of Active Trachoma in Gambian Children
BACKGROUND: Susceptibility and resistance to trachoma, the leading infectious cause of blindness, have been associated with a range of host genetic factors. In vitro studies of the causative organism, Chlamydia trachomatis, demonstrate that iron availability regulates its growth, suggesting that host genes involved in regulating iron status and/or availability may modulate the risk of trachoma. The objective was to investigate whether haptoglobin (Hp) haplotypes constructed from the functional polymorphism (Hp1/Hp2) plus the functional promoter SNPs -61A-C (rs5471) and -101C-G (rs5470), or sickle cell trait (HbAS, rs334) were associated with risk of active trachoma when stratified by age and sex, in rural Gambian children. METHODOLOGY AND PRINCIPAL FINDINGS: In two cross sectional surveys of children aged 6-78 months (n = 836), the prevalence of the clinical signs of active trachoma was 21.4%. Within boys, haplotype E (-101G, -61A, Hp1), containing the variant allele of the -101C-G promoter SNP, was associated with a two-fold increased risk of active trachoma (OR = 2.0 [1.17-3.44]). Within girls, an opposite association was non-significant (OR = 0.58 [0.32-1.04]; P = 0.07) and the interaction by sex was statistically significant (P = 0.001). There was no association between trachoma and HbAS. CONCLUSIONS: These data indicate that genetic variation in Hp may affect susceptibility to active trachoma differentially by sex in The Gambia
GWAS of Follicular Lymphoma Reveals Allelic Heterogeneity at 6p21.32 and Suggests Shared Genetic Susceptibility with Diffuse Large B-cell Lymphoma
Non-Hodgkin lymphoma (NHL) represents a diverse group of hematological
malignancies, of which follicular lymphoma (FL) is a prevalent subtype. A
previous genome-wide association study has established a marker, rs10484561 in
the human leukocyte antigen (HLA) class II region on 6p21.32 associated with
increased FL risk. Here, in a three-stage genome-wide association study,
starting with a genome-wide scan of 379 FL cases and 791 controls followed by
validation in 1,049 cases and 5,790 controls, we identified a second independent
FL–associated locus on 6p21.32, rs2647012
(ORcombined = 0.64,
Pcombined = 2×10−21)
located 962 bp away from rs10484561 (r2<0.1 in controls). After
mutual adjustment, the associations at the two SNPs remained genome-wide
significant (rs2647012:ORadjusted = 0.70,
Padjusted = 4×10−12;
rs10484561:ORadjusted = 1.64,
Padjusted = 5×10−15).
Haplotype and coalescence analyses indicated that rs2647012 arose on an
evolutionarily distinct haplotype from that of rs10484561 and tags a novel
allele with an opposite (protective) effect on FL risk. Moreover, in a follow-up
analysis of the top 6 FL–associated SNPs in 4,449 cases of other NHL
subtypes, rs10484561 was associated with risk of diffuse large B-cell lymphoma
(ORcombined = 1.36,
Pcombined = 1.4×10−7).
Our results reveal the presence of allelic heterogeneity within the HLA class II
region influencing FL susceptibility and indicate a possible shared genetic
etiology with diffuse large B-cell lymphoma. These findings suggest that the HLA
class II region plays a complex yet important role in NHL
Pseudoneoplastic lesions of the testis and paratesticular structures
Pseudotumors or tumor-like proliferations (non-neoplastic masses) and benign mimickers (non-neoplastic cellular proliferations) are rare in the testis and paratesticular structures. Clinically, these lesions (cysts, ectopic tissues, and vascular, inflammatory, or hyperplastic lesions) are of great interest for the reason that, because of the topography, they may be relevant as differential diagnoses. The purpose of this paper is to present an overview of the pseudoneoplasic entities arising in the testis and paratesticular structures; emphasis is placed on how the practicing pathologist may distinguish benign mimickers and pseudotumors from true neoplasia. These lesions can be classified as macroscopic or microscopic mimickers of neoplasia
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