Browsing by Subject "Biochemistry"

Now showing 1 - 3 of 3

Open Access
Chromium(VI) biosorption and bioaccumulation by Live and acid-modified biomass of a novel morganella morganii isolate
(Taylor and Francis, 2014) Ergul-Ulger, Z.; Ozkan A.D.; Tunca E.; Atasagun, S.; Tekinay, T.
Conventional methods of chromium removal are often insufficient for the remediation of chromium-contaminated natural environments, necessitating the development of alternative strategies. In this paper, we report the isolation of a novel Morganella morganii strain capable of reducing hexavalent chromium to its less-toxic and less-soluble trivalent form. Cr(VI) reduction by this strain was evaluated in both acidic environments and conditions reflecting natural freshwater sources. The isolate achieved equilibrium within 3 h and displayed a specific uptake rate of 24.30 ± 1.67 mg Cr(VI)/g biomass following HCl treatment. Without acid treatment, a reduction of over 90% was recorded within 72 h for an initial Cr(VI) concentration 20 mg/L, corresponding to a Cr(VI) removal capacity of 19.36 ± 1.89 mg/g. Absorption data of acid-treated STB5 biomass most closely followed the Toth and Langmuir models. FTIR results indicate that hydroxyl groups and extracellular or cell membrane polysaccharides may be potential adsorption sites for hexavalent chromium. Our results suggest that the isolate may be used in situ for treatment of polluted freshwater environments. Copyright © Taylor & Francis Group, LLC.
Open Access
Differences in the accumulation and distribution profile of heavy metals and metalloid between male and female crayfish (Astacus leptodactylus)
(2013) Tunca, E.; Ucuncu, E.; Ozkan, A.D.; Ulger, Z.E.; Cansizoǧlu, A.E.; Tekinay, T.
Concentrations of selected heavy metals and a metalloid were measured by ICP-MS in crayfish (Astacus leptodactylus) collected from Lake Hirfanli, Turkey. Aluminum (Al), chromium (52Cr, 53Cr), copper ( 63Cu, 65Cu), manganese (Mn), nickel (Ni) and arsenic (As) were measured in the exoskeleton, gills, hepatopancreas and abdominal muscle tissues of 60 crayfish of both genders. With the exception of Al, differences were determined between male and female cohorts for the accumulation trends of the above-mentioned elements in the four tissues. It was also noted that the accumulation rates of Ni and As were significantly lower in gill tissue of females compared to males and no significant difference was observed for Cu isotopes in female crayfish. Cluster Analysis (CA) recovered similar results for both genders, with links between accumulations of Ni and As being notable. Accumulation models were described separately for male and female crayfish using regression analysis, and are presented for models where R2 > 0.85. © 2013 Springer Science+Business Media New York.
Open Access
An exploration of organizational factors in new product development success
(Emerald Publishing, 2006) Kandemir, D.; Calantone, R.; Garcia, R.
Purpose - This study surveys a broad spectrum of new product development (NPD) projects from the biochemistry industry in the USA, Canada, Germany, the UK, and Belgium with the purpose of exploring the role of the organizational activity factors in the NPD success. Design/methodology/approach - Drawing on the resource-based view of the firm, the authors present a set of hypotheses concerning the relationship between the people resources, development resources, testing resources, and launch resources committed to NPD projects and their financial success. In addition, the effect of the firm's international market involvement on the NPD project success is considered. In this study, testing of the hypothesized relationship is accomplished through linear probability model, binary probit model, and binary logit model. Findings - Empirical results generally support the predictions from the theory. Specifically, the findings of this study show that: the involvement of a strong champion, use of a multi-disciplinary team, and focus of a dedicated team are key factors for NPD project success among the people resources; the detailed market research has a significant impact on the project success in the development phase of the NPD process; the allocation of resources to the testing of the product with the final customer, market testing, and production start-up positively influences the NPD project success; advertising quality plays a key role in the NPD project success during its launch; and the NPD project success is positively associated with the degree of a firm's diversification into international markets. Originality/value - This study provides several guidelines for product managers seeking to launch new products. It offers critical insights into the identification of firm resources that influence the NPD project success. This study also has important implications for firms that consider diversifying or have already diversified into international markets. Understanding the role of market diversification in the NPD project success advances the ability of managers to direct their efforts in international market involvement.