Corrosion susceptibilities of Al-Cu/TiC MMCs fabricated by conventional hot pressing

303-308The effect of TiC particle volume fraction on the electrochemical behaviours of metal matrix composites (MMCs), which is Al-Cu based reinforced with TiCp has been investigated in both aerated and deaerated 1.0 N H₂₄SO₄ aqueous solutions. Composites reinforced with TiC particles at volume fractions of 20, 30 and 40% have been produced by conventional hot pressing method and then, artificially aged (T6). The corrosion susceptibilities of the composites have been analyzed by using the cyclic potentiodynamic polarization technique. The surface morphology of the composites has been determined by scanning electron microscopy (SEM). The results show that the corrosion susceptibilities of the composites increase with increased TiC particle content but decreases with T6 heat treatment performed on the composites

An EPQ model with imperfect items using interval grey numbers

The classic economic production quantity (EPQ) model has been widely used to determine the optimal production quantity. However, the analysis for finding an EPQ model has many weaknesses which lead many researchers and practitioners to make extensions in several aspects on the original EPQ model. The basic assumption of EPQ model is that 100% of manufactured products are non-defective that is not valid for many production processes generally. The purpose of this paper is to develop an EPQ model with grey demand rate and cost values with maximum backorder level allowed with the good quality items in units under an imperfect production process. The imperfect items are considered to be low quality items which are sold to a particular purchaser at a lower price and, the others are reworked and scrapped. A mathematical model is developed and then an industrial example is presented on the wooden chipboard production process for illustration of the proposed model

Triterpene glycosides from Astragalus icmadophilus

Six cycloartane-type triterpene glycosides were isolated from Astragalus icmadophilus along with two known cycloartane-type glycosides, five known oleanane-type triterpene glycosides and one known flavonol glycoside. The structures of the six compounds were established as 3-O-[alpha-L-arabinopyranosyl-(1 -> 2)-O-3-acetoxy-alpha-L-arabinopyranosyl]-6-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta,24(S),25-pentahydroxy-cycloartane, 3-O-[alpha-L-rhamnopyranosyl-(1 -> 2)-O-alpha-L-arabinopyranosyl-(1 -> 2)-O-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta,24(S),25-pentahydroxy cycloartane, 3-O-[alpha-L-arabinopyranosyl-(1 -> 2)-O-3,4-diacetoxy-alpha-L-arabinopyranosyl]-6-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta,24(S),25-pentahydroxy cycloartane, 3-O-[alpha-L-arabinopyranosyl-(1 -> 2)-O-3-acetoxy-alpha-L-arabinopyranosyl]-6-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta,25-tetrahydroxy-20(R),24(S)-epoxycycloartane, 3-O-[alpha-L-arabinopyranosyl-(1 -> 2)-O-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta,24 alpha-tetrahydroxy-20(R),25-epoxycycloartane, 3-O-[alpha-L-rhamnopyranosyl-(1 -> 2)-O-alpha-L-arabinopyranosyl-(1 -> 2)-O-beta-D-xylopyranosyl]-6-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta,24 alpha-tetrahydroxy-20(R),25-epoxycycloartane by the extensive use of 1D- and 2D-NMR experiments along with ESIMS and HRMS analysis. The first four compounds are cyclocanthogenin and cycloastragenol glycosides, whereas the last two are based on cyclocephalogenin as aglycone, more unusual in the plant kingdom, so far reported only from Astragalus spp

Saponins from Astragalus hareftae (NAB.) SIRJ.

WOS: 000311260100017PubMed ID: 22925830Four cycloartane- (hareftosides A-D) and oleanane-type triterpenoids (hareftoside E) were isolated from Astragalus hareftae along with fifteen known compounds. Structures of the compounds were established as 3,6-di-O-beta-D-xylopyranosyl-3 beta,6 alpha, 16 beta,24(S),25-pentahydroxycycloartane (1), 3,6,24-tri-O-beta-D-xylopyranosyl-3 beta,6 alpha,16 beta,24(S),25-pentahydroxycycloartane (2), 3-O-beta-D-xylopyranosyl-3 beta,6 alpha,16 beta,25-tetrahydroxy-20(R),25(S)-epoxycycloartane (3), 16-O-beta-D-glucopyranosyl-3 beta,6 alpha,16 beta,25-tetrahydroxy-20(R), 24(S)-epoxycycloartane (4), 3-O-[beta-D-xylopyranosyl-(1 -> 2)-O-beta-D-glucopyranosyl-(1 -> 2)-O-beta-D-glucuronopyranosyl]-soyasapogenol B (5) by the extensive use of 1D- and 2D-NMR experiments along with ESI-MS and HR-MS analyses. (c) 2012 Elsevier Ltd. All rights reserved.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [109T425]; EBILTEMEge University [2010/BIL/008]; Ege University Research FoundationEge University [2009 Fen 090]The authors are grateful to TUBITAK (109T425), EBILTEM (2010/BIL/008) and also Ege University Research Foundation (2009 Fen 090) for financial support

Cycloartane glycosides from Astragalus aureus

WOS: 000290505500011PubMed ID: 21377702Eight cycloartane-type triterpene glycosides (1-8) were isolated from Astragalus aureus Willd along with ten known cycloartane-type glycosides (9-18). Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. Compounds 1-5 are cyclocanthogenin glycosides, whereas compounds 6-8 are based on cyclocephalogenin as aglycon, more unusual in the plant kingdom, so far reported only from Astragalus spp. Moreover, for the first time monoglycosides of cyclocanthogenin (5) and cyclocephalogenin (7, 8) are reported. All of the compounds tested for their cytotoxic activities against a number of cancer cell lines. Among the compounds, only 8 exhibited activity versus human breast cancer (MCF7) at 45 mu M concentration. (C) 2011 Elsevier Ltd. All rights reserved.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [109T425]; Ege University Research FoundationEge University [2009 Fen 045]; EBILTEMEge University [2010/BIL/008]This project was supported by TUBITAK (109T425), Ege University Research Foundation (2009 Fen 045) and EBILTEM (2010/BIL/008)

Secondary Metabolites from Astragalus lycius and Their Cytotoxic Activities

WOS: 000390975600018PubMed ID: 30508348Eight known secondary metabolites were isolated from the methanolic extract of the whole plant of Astragalus lycius Boiss. They were identified as 5,5'-dihydroxy-3'-methoxy-isoflavone-7-O-beta-D-glucoside (1), genistin (2), sissotrin (3), 5,4'-dimethoxy-isoflavone-7-O-beta-D-glucopyranoside (4), (7S,8R)-5-methoxydehydrodiconiferyl alcohol-4-O-beta-D-glucopyranoside (5), 4-O-lariciresinol-glucoside (6), 2-phenylethyl-beta-D-glucopyranoside (7) and beta-isitosterol-3-O-beta-D-glucopyranoside (8) by spectroscopic methods including H-1- and C-13-NMR and HR-MS experiments, and by comparison with literature values. Compounds 1-7 are reported for the first time from Astragalus taxa. All of the compounds were tested for their cytotoxic activities against a number of cancer cell lines. Among them, only 6 exhibited significant activity against human colon carcinoma (HT-29) at 2.69 mu M concentration.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [109T425]; Ege University Research FoundationEge University [2009 Fen 090]; EBILTEMEge University [2010/BIL/008]The authors are grateful to TUBITAK (109T425), Ege University Research Foundation (2009 Fen 090) and EBILTEM (2010/BIL/008) for the financial support, and also we are grateful to Dr. Kemal S. Korkmaz for letting us to carry out the cytotoxicity assays in his laboratory (KK Cancer Biology Lab)

Secondary metabolites from astragalus lycius and their cytotoxic activities

Eight known secondary metabolites were isolated from the methanolic extract of the whole plant of Astragalus lycius Boiss. They were identified as 5,5'-dihydroxy-3'-methoxy-isoflavone-7-O-β-D-glucoside (1), genistin (2), sissotrin (3), 5,4'-dimethoxy-isoflavone-7-O-β-D-glucopyranoside (4), (7S,8R)-5-methoxydehydrodiconiferyl alcohol-4-O-β-D-glucopyranoside (5), 4-O-lariciresinol-glucoside (6), 2-phenylethyl-β-D-glucopyranoside (7) and β-sitosterol-3-O-β-D-glucopyranoside (8) by spectroscopic methods including 1H- and 13C-NMR and HR-MS experiments, and by comparison with literature values. Compounds 1-7 are reported for the first time from Astragalus taxa. All of the compounds were tested for their cytotoxic activities against a number of cancer cell lines. Among them, only 6 exhibited significant activity against human colon carcinoma (HT-29) at 2.69 μM concentration.TUBITAK (109T425); Ege University Research Foundation (2009 Fen 090); EBILTEM (2010/BIL/008