Kapaciteti posmične sile spojeva namještaja H-tipa izrađenoga od različitih toplinski tretiranih vrsta drva

The aim of this study was to investigate the effect of wood species, heat treatment, adhesive type and joint technique on shear force capacity of H-type furniture joints. For this purpose, an experimental design that consisted of 3 wood species, 2 treatment processes (untreated, heat-treated), 2 adhesive types (polyurethane (PUR), polyvinyl acetate (PVAc)) and 2 joint techniques (dowel, mortise-tenon (MT)) and 5 replications for each group were prepared, and accordingly, a total of 120 specimens were tested under static shear loads. Siberian pine (Pinus sibirica), Iroko (Chlorophora excelsa), and common ash (Fraxinus excelsior), which are commonly used in furniture constructions, were used as wood species. In general, iroko showed the highest shear force capacity between the wood species. The specimens constructed of heat-treated wood species showed lower shear force capacity by approximately 15 % in comparison to the same untreated specimens. MT joints showed better performance than dowel joints higher by approximately 21 %. PVAc adhesive gave higher values than PU adhesive by around 5 %. According to the results of four-way interactions, highest shear force capacities of H-type joints were obtained from “Common ash-PVAc-MT” combination in groups of untreated specimens and from “Iroko-PU-MT” combination in groups of heat-treated specimens.Cilj ovog istraživanja bio je ispitati utjecaj vrste drva, njegove toplinske obrade, vrste ljepila i tehnike spajanja na kapacitet posmične sile spojeva namještaja H-tipa. Za tu je namjenu pripremljen eksperiment s ovim parametrima: tri vrste drva, dvije obrade (netretirani i toplinski tretiran namještaj), dvije vrste ljepila (poliuretan – PUR, polivinilacetat – PVAc) i dvije tehnike spajanja (moždanikom te čepom i rupom – MT). Za svaki sustav pripremljeno je pet uzoraka te je pri statičkom posmičnom opterećenju ispitano ukupno 120 uzoraka. Odabrane su vrste drva koje se često upotrebljavaju u konstrukcijama namještaja: sibirski bor (Pinus sibirica), iroko (Chlorophora excelsa) i jasen (Fraxinus excelsior). Prema rezultatima istraživanja, drvo iroka pokazalo je najveći kapacitet posmične sile od svih ostalih vrsta drva obuhvaćenih eksperimentom. Uzorci izrađeni od toplinski obrađenog drva imali su oko 15 % manje vrijednosti kapaciteta posmične sile od netretiranih uzoraka. MT spojevi pokazali su za oko 21 % veće vrijednosti od spojeva s moždanicima. Uz upotrebu PVAc ljepila vrijednosti su bile za oko 5 % veće od vrijednosti s PUR ljepilom. Prema rezultatima četverosmjernih interakcija, najveći kapaciteti posmične sile spojeva H-tipa dobiveni su za kombinaciju jasenovina – PVAc – MT u netretiranim uzorcima i za kombinaciju drvo iroka – PUR – MT u toplinski tretiranim uzorcima

Genotoxic, Cytotoxic, and Apoptotic Effects of Hypogymnia physodes (L.) Nyl. on Breast Cancer Cells

The aim of this study is to determine the chemical composition, and evaluate the genotoxic, and anti-growth potency of the methanol extracts of lichen species Hypogymnia physodes (L.) Nyl. (HPE). Anti-growth effect was tested in two different human breast cancer cell lines (MCF-7 and MDA-MB-231) by the MTT and ATP viability assays and apoptosis was assayed by the caspase-cleaved cytokeratin 18 (M30-antigen). Genotoxic activity of HPE was studied using chromosome aberration and micronuclei tests in human lymphocytes culture in vitro. The chemical composition of H. physodes was analyzed by using direct thermal desorption method coupled with comprehensive gas chromatography-time of flight mass spectrometry (GCXGC-TOF/MS). Our results indicate that HPE has an anti-growth effect at relatively lower concentrations, while relatively higher concentrations are required for genotoxic activity. HPE, therefore, seems to represent a therapeutic potential and poses new challenges for medicinal chemistry. (C) 2012 Wiley Periodicals, Inc