GARDINERIN, A BIOLOGICALLY ACTIVE ACETOGENIN FROM THE SRI LANKAN GONIOTHALAMUS GARDINERI HOOK. F. AND THOMSON

Objective: The study was undertaken to isolate biologically active compounds from Goniothalamus gardineri, a plant endemic to Sri Lanka. Methods: Roots and flowers of Goniothalamus gardineri were extracted into dichloromethane and methanol. A new acetogenin, gardinerin isolated by column chromatography of the dichloromethane extract was structurally characterized using NMR and Mass spectroscopies. It was found to be mosquito larvicidal (against 2nd instar larvae of Aedes aegypti), cytotoxic (in the brine shrimp assay) and antioxidant (DPPH assay). Results: Gardinerin exhibited potent mosquitolarvicidal activity (LC50 = 0.0744±0.37 ppm.), cytotoxicity (LC50 = 1.5±0.37 ppm) and antioxidant activity (IC50 =10.02±0.01 ppm). The same extract furnished (5R)-goniothalamin. The hexane extract of the flowers of G. gardineri yielded poriferesterol and stigmast-4, 22-dien-3-one.Conclusion: The endemic plant G. gardineri has yielded an acetogenin possessing highly potent antioxidant, cytotoxic and mosquitolarvicidal activity. Â

Web Crippling Behaviour of Cold-Formed Carbon Steel, Stainless Steel, and Aluminium Lipped Channel Sections with Web Openings

This paper reviews the research advancements and design practices related to the structural web crippling response of lipped Cold-Formed (CF) carbon steel, stainless steel, and aluminium channels with web perforations. The web crippling response differs among each material based on the non-linear stress-strain characteristics and degree of strain hardening. Therefore, the reduction in the web crippling strength of web-perforated CF channel sections made of different materials may not be equivalent. The research activities surrounding the web crippling response of CF channels with and without web openings were reviewed initially. Despite the limited design provisions given in the international specifications for the web crippling design of lipped CF channels with web openings, web crippling studies conducted across the world have developed suitable design equations in the form of reduction factors. Past research studies have substantially captured the web crippling response of carbon steel channels with web openings while that of stainless steel and aluminium are limited, as identified in this paper. Lastly, numerical models were developed for simulating the web crippling behaviour of lipped CF carbon steel, stainless steel, and aluminium channels with web opening and validated with past experimental data, with a view for developing unified design guidelines

Genetic, familial and environmental correlates of asthma among early adolescents in Sri Lanka: a case control study

Background Despite advances in management, the mortality and morbidity due to asthma are increasing globally. Identification of specific correlates in the local context is useful in disease management. The objective of this study was to estimate the prevalence and to describe selected correlates of asthma among12-14 year old school children in a district in Sri Lanka.Method A school based cross-sectional study was conducted using a self administered questionnaire. Multi-staged stratified cluster sampling was used to select 42 classes in grades 7, 8 and 9. “Current asthma” (CA)(case) was defined as ‘having Physician Diagnosed Asthma (PDA) and having had wheezing during the previous 12 months’. For each case, two healthy controls were selected from the same class to assess correlates. Information on correlates was collected by trained field midwives during home visits. Backward stepwise logistic regression model was used for analysis of correlates. Skin Prick Testing was carried out among asthmatics together with their healthy siblings using standard extracts of House Dust Mite (HDM), cockroach and Blomia. Ethical clearance was obtained from Ethical Review Committee, Faculty of Medicine, Colombo.Results Out of 1483 subjects participated, 753 were females (50.8%). The prevalence rates for current wheezing (CW), ever wheezing (EW), current asthma (CA), and physician diagnosed asthma (PDA) were 16.7%, 19.4%, 10.7% and 14.5% respectively. A total of 158 CA cases were identified. Information on correlates of asthma was collected for 145 CA cases (97.9%) and for 285 controls (96.6%). The unconfounded predictors of having CA among adolescents in the present sample were; only child in the family (OR = 4.2, 95% CI: 1.7-9.9); first born of the family (OR = 2.6 95% CI: 1.3-5.2); presence of allergic rhinitis (OR = 2.7, 95% CI: 1.6-4.6); family history of asthma (OR = 1.8, 95% CI: 1.1-3.2); family history of allergic rhinitis (OR = 1.9, 95% CI: 1.1-3.2); family history of eczema (OR = 1.8, 95% CI: 1.0-3.2). Higher risk of sensitization to cockroach, HDM and Blomia was seen among asthmatics compared to healthy siblings.Conclusion A significant proportion of students reported to have asthma. Atopy and other genetic and environmental correlates should be considered as important correlates in asthma management among early adolescents in Sri Lanka. Keywords: Asthma, Atopy, Adolescents, Sri Lanka, Skin prick tes