The relationship between urinary organophosphate pesticide residues and reproductive development among boys living in the rural Western Cape

Background: Many contemporary agricultural pesticides are hormonally active, but few previous studies have investigated their effect on the reproductive health and growth of pubertal boys. A previous analysis found significant differences in serum reproductive hormone levels and lower anthropometric measurements as well as non-significant lower sexual maturity ratings and testicular sizes in farm boys compared to non-farm boys from the rural Western Cape in South Africa. Methodology: This analysis included 183 out of 269 school boys residing on farms and neighbouring nonfarming areas who provided urine samples in a cross-sectional study. Measurements included a questionnaire, clinical assessment of sexual maturity development (SMD), anthropometric measurements (height, weight and body mass index (BMI)), serum reproductive hormones (including luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and oestradiol (E2)) and urinary levels of 3 dialkyl phosphates (organophosphate pesticide metabolites) including di-ethyl, di-methyl and di-methyl triphosphate (DEP, DMP and DMTP). Results: The median (interquartile range) of age and sum dialkyl phosphates of the school boys was 12 years (9-13 years) and 68.3 ng/mL (27.9-129.5 ng/mL) respectively. There were consistent, mostly non-significant associations with some dose response relationships between urinary levels of dialkyl phosphates and adverse effects on outcomes including SMD, serum reproductive hormones and anthropometric development. The strongest results included a strong positive association and dose response found between serum oestradiol > the 50th percentile and quartiles DMTP (odd ratio and confidence interval for highest and lowest quartile: 7.4; 1.7-32.4) and between BMI <50th percentile and quartiles of DMTP (odd ratio and confidence interval for highest and lowest quartile: 3.2; 1.2-9.0). Conclusion: The results provide some preliminary evidence that organophosphate pesticides exposure could alter the reproductive hormone levels and adversely affect the body size of school boys. There was also lack of evidence of other adverse effects on reproductive development. These findings require further investigation in a larger longitudinal study with seasonal bio-monitoring for pesticides

Infinite families of finite string rewriting systems and their confluence

International audienceWe introduce parameterized rewrite systems for describing infinite families of finite string rewrite systems depending upon non-negative integer pa- rameters, as well as ways to reason uniformly over these families. Unlike previous work, the vocabulary on which a rewrite system in the family is built depends it- self on the integer parameters. Rewriting makes use of a toolkit for parameterized words which allows to describe a rewrite step made independently by all systems in an infinite family by a single, effective parameterized rewrite step. The main result is a confluence test for all systems in a family at once, based on a critical pair lemma classically based on computing finitely many overlaps between left- hand sides of parameterized rules and then checking for their joinability (which decidability is not garanteed)

Evaluating pixel and object based image classification techniques for mapping plant invasions from UAV derived aerial imagery : Harrisia pomanensis as a case study

Invasive alien plants (IAPs) not only pose a serious threat to biodiversity and water resources but also have impacts on human and animal wellbeing. To support decision making in IAPs monitoring, semi-automated image classifiers which are capable of extracting valuable information in remotely sensed data are vital. This study evaluated the mapping accuracies of supervised and unsupervised image classifiers for mapping Harrisia pomanensis (a cactus plant commonly known as the Midnight Lady) using two interlinked evaluation strategies i.e. point and area based accuracy assessment. Results of the point-based accuracy assessment show that with reference to 219 ground control points, the supervised image classifiers (i.e. Maxver and Bhattacharya) mapped H. pomanensis better than the unsupervised image classifiers (i.e. K-mediuns, Euclidian Length and Isoseg). In this regard, user and producer accuracies were 82.4% and 84% respectively for the Maxver classifier. The user and producer accuracies for the Bhattacharya classifier were 90% and 95.7%, respectively. Though the Maxver produced a higher overall accuracy and Kappa estimate than the Bhattacharya classifier, the Maxver Kappa estimate of 0.8305 is not significantly (statistically) greater than the Bhattacharya Kappa estimate of 0.8088 at a 95% confidence interval. The area based accuracy assessment results show that the Bhattacharya classifier estimated the spatial extent of H. pomanensis with an average mapping accuracy of 86.1% whereas the Maxver classifier only gave an average mapping accuracy of 65.2%. Based on these results, the Bhattacharya classifier is therefore recommended for mapping H. pomanensis. These findings will aid in the algorithm choice making for the development of a semi-automated image classification system for mapping IAPs.The South African National Department of Environment Affairs through its funding of the South African National Biodiversity Institute Invasive Species Programme, project number P038.http://www.elsevier.com/ locate/ isprsjprs2018-07-30hj2018Geography, Geoinformatics and Meteorolog

Verification of the folkloric and anecdotal antidiabetic effects of Hypoxis hemerocallidea (Fisch., CA Mey. & Ave-Lall) and isolated, beta-sitosterol using early-stage type II spontaneous diabetic mutant BKS-Lepr(db) mice

BACKGROUND : Previous studies in our laboratory in ex vivo assays have demonstrated H. hemerocallidea extract as potential antidiabetic agent through increased insulin release from pancreatic beta cells. Thus, for this study the early stage type II spontaneous diabetic mutant mice model was used to evaluate and determine the degree of the antidiabetic efficacy of H. hemerocallidea. METHODS : Eight-weeks-old type II spontaneous pre-diabetic mutant BKS-Leprdb mice were fed with feed supplemented with either H. hemerocallidea extract, isolated compound (β-sitosterol) or chlorpropamide (positive control) for 4 weeks. The haematological parameters, clinical chemistry, glucose tolerance, feed intake, faecal output and body weights were measured. RESULTS : The blood glucose concentrations of all the animals treated with plant extract, β-sitosterol compound and non-treated pre-diabetic animals did not return to baseline levels. Only the β-sitosterol treatment and positive control groups resulted in a respective small decrease of 5.8 and 5.2% in the mouse weights over the study period, with no significant changes (p > 0.05) in food intake. However, there was a general trend for decrease in faecal output for all the groups. Albumin, triglycerides, and total cholesterol levels in β-sitosterol and chlorpropamide-treated animals were lower, relative to untreated-animals. Animals fed with plant extract showed large amounts of internal fat. There were no significant changes (p > 0.05) in total serum protein, globulin, alanine aminotransferase, alkaline phosphatase, urea nitrogen and creatinine attributed to administration of treatments. In all groups, some animals showed lesions associated with cardiac puncture. Few animals except animals treated with plant extract, showed presence of a leftventricular hypertrophic cardiomyopathy. The liver and kidneys for all groups appeared macroscopically normal and the thymuses were small (±2 mg). There were pathological signs in some of the animals particularly in myocardial fibres, renal tubular, glomerular, hepatocyte granularity and pancreas islets. However, there was no significance trend between the groups. CONCLUSION : Based on the results, none of the treatments could be considered highly effective for the management of type II pre-diabetes as sole therapeutic intervention.The Department of Higher Education and training (DHET) Research Development Grant (RDG) and Faculty of Veterinary Science University of Pretoria.https://bmccomplementmedtherapies.biomedcentral.comam2023Paraclinical Science

Security Testing: A Survey

Identifying vulnerabilities and ensuring security functionality by security testing is a widely applied measure to evaluate and improve the security of software. Due to the openness of modern software-based systems, applying appropriate security testing techniques is of growing importance and essential to perform effective and efficient security testing. Therefore, an overview of actual security testing techniques is of high value both for researchers to evaluate and refine the techniques and for practitioners to apply and disseminate them. This chapter fulfills this need and provides an overview of recent security testing techniques. For this purpose, it first summarize the required background of testing and security engineering. Then, basics and recent developments of security testing techniques applied during the secure software development lifecycle, i.e., model-based security testing, code-based testing and static analysis, penetration testing and dynamic analysis, as well as security regression testing are discussed. Finally, the security testing techniques are illustrated by adopting them for an example three-tiered web-based business application

Anti-diabetic activity of extracts and a bioactive compound isolated from Hypoxis hemerocallidea (Hypoxidaceae) in a murine model of spontaneous diabetes

A previous study investigated and demonstrated that Hypoxis hemerocallidea (Fisch and Mey) (Hypoxidaceae) corm extracts used traditionally, stimulated insulin secretion from pancreatic _ cells maintained under ex vivo conditions. The effect was also related to the antioxidant activity of extracts. In order to find leads with unique chemical structures which may exert a hitherto unexploited mode of action, phytochemical investigation on extracts of the plant was carried out. This involved the following steps: authentication and extraction of the plant material, separation and isolation of the constituents of interest, characterization of the isolated compounds and quantitative evaluation. Furthermore, the following study also followed the normal sequence of principles of replacement, in that all necessary non-animal and ex vivo animal models were first to optimise evaluation of the product, before testing using a mouse model. With H. hemerocallidea being traditionally used as wild bulbs, we firstly ascertained the risk of this tradional use with specific focus on heavy metals. This is important as certain soil minerals are known to increase antioxidant capacity in plants, and associated extracts, as a stress response to soil heavy metal content. However, the use of these wild plants may pose a safety concern to the person consuming the plant as a result of their potential heavy metal content. Corms collected from the wild from five different geographical regions of South Africa, were evaluated for their concentration of metal concentrations and associated antioxidant activity. Among the trace metals investigated, iron was the highest, for the corm collected from Ga-rankuwa. No link was found between the corm’s antioxidant activity and environmental conditions. We further investigated the corm from Ga-rankuwa, since it had the highest antioxidant activity for its anti-diabetic activity. Assays included glucose uptake in C2C12 myocytes, 3T3-L1 preadipocytes and insulin secretion in rat insulinoma RiNm5F cells in total five different fractions and three compounds isolated. Only the methanol crude extract, fraction III & V and isolated _-sitosterol significantly increased insulin release and lowered blood glucose levels both in C2C12 myocytes and 3T3-L1 preadipocytes to a degree. All the crude extracts, fractions and tested compounds had relatively low cytotoxicity against all the diabetic cell lines used. In the final study we determined the effect of H. hemerocallidea and its isolated compound, _-sitosterol in a murine mouse model of spotaneous diabetes. The _-sitosterol induced slight weight loss in the mice and stabilised blood glucose concentration after the 4 weeks treatment course. No changes in the haematology were evident while clinical chemistry evaluations showed slight treatment-related changes in triglycerides and total cholesterol. The study concludes that H. Hemerocallidae was not a suitable as a sole treatment agent in the management of diabetes. However it holds promise as an add-on treatment to lifestyle intervention for the management of type-II diabetes.Thesis (PhD)--University of Pretoria, 2019.Paraclinical SciencesPhDUnrestricte

Propriétés uniformes de familles de systèmes de réécriture de mots paramétrées par des entiers

Dans cette thèse nous proposons un formalisme étendant la notion de réécriture contrainte sur les mots : la réécriture paramétrée. Cette dernière permet de décrire de façon uniforme des familles, éventuellement infinies, de systèmes de réécriture de mots qui dépendent de paramètres entiers. Ce formalisme permet l'étude des propriétés uniformes des familles de structures algébriques présentées par de tels systèmes. Par exemple, nous traitons le cas de la famille composée des groupes de permutations d'ordre N, où N est un paramètre prenant ses valeurs dans les entiers naturels. Nous donnons des algorithmes permettant de faire des preuves équationelles qui sont correctes, dites preuves uniformes, pour toutes les valeurs des paramètres. Ensuite nous étudions les preuves par réécriture et montrons un lemme des paires critiques analogue à celui présent en réécriture standard. Nous en déduisons un algorithme de complétion pour les systèmes de réécriture paramétrés. Enfin nous proposons un algorithme permettant le calcul du cardinal de l'ensemble des formes normales des algèbres paramétrées. Au fil du manuscrit, nous présentons une syntaxe pour la réécriture paramétrée qui est très proche de celle utilisée en mathématique pour présenter équationellement des structures dénombrablement engendrées. Nous indiçons les lettres par des expression arithmétiques, puis nous définissons les notions de mots avec exposants entiers et les mots contenant des produits finis. Par l'étude de nombreux exemples issus de la littérature mathématique, nous montrons que notre formalisme permet de représenter et d'étudier automatiquement des familles de structures qui auparavant nécessitaient de longs raisonnements mathématiques fastidieux.In this thesis, we introduce a formalism extending the string contrained rewriting : the parameterized string rewriting. It enables one to describe uniformly infinite families of string rewriting systems which depend on integers parameters. With this formalism, one can study uniform properties of algebraic structures families presented by such systems. For example, we study the family composed of the groups of permutations of order N, where N is a parameter with values in the non negative integers. We give algorithms to build equational proofs that are correct for each value of the parameters. Thereafter we study rewriting proofs and prove a critical pair lemma for parameterized rewriting, which is very similar to the one in classical rewriting. We give a completion algorithm for parameterized rewriting. Finally we propose an algorithm which computes the cardinal of the set of normal forms in parameterized algebras. The syntax that we introduce in the document is very close to the syntax used in mathematics to give equational presentations of denumerable generated structures. We use letters indexed by arithmetic expressions, words with integers exponents and finite products. Through several examples, coming from mathematical literature, we show our formalism in action, studying automatically infinite families of structures which would be studied with long and tedious mathematical proofs.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF