Titanium Ions Release from an Innovative Titanium-Magnesium Composite: an in Vitro Study

Svrha: U ovom radu istraživala su se korozijska svojstva inovativnog titanij-magnezijeva (Ti-Mg) kompozita proizvedenog metodom metalurgije praha (P/M). Materijal i metode: Ispitivane su dvije grupe eksperimentalnog materijala – s 1 masenim udjelom (mass% Ti-1Mg) i 2 masena udjela (mass% Ti-2Mg) magnezija u titanijskoj osnovi te su uspoređene s komercijalno čistim titanijem (CP Ti). Test uranjanja i kemijska analiza četiriju otopina: umjetne sline, umjetne sline pH 4, umjetne sline s dodatkom fluora i Hankove otopine, provedeni su nakon 42 dana uranjanja metodom masene spektrometrije induktivno spregnutom plazmom (ICP – MS) kako bi se ustanovila količina otpuštenih iona titanija (Ti). Za određivanje svojstava površine korištene su analize SEM i EDS. Rezultati: Razlika u rezultatima između različitih ispitivanih otopina procjenjivana je ANOVA-om i Newman-Keulsovim testom na razini značajnosti od p < 0,05. Utjecaj prediktorskih varijabli utvrđivan je multiplom regresijskom analizom. Rezultati ovog istraživanja pokazuju nisku stopu korozije titanija u ispitivanoj skupini Ti-Mg. Uočeno je do 46 puta, odnosno 23 puta manje otapanje iona titanija iz Ti-1Mg i Ti-2Mg u usporedbi s kontrolnom skupinom. Između ispitivanih otopina, umjetna slina s dodatkom fluora pokazala je najveći korozijski učinak među svim ispitivanim uzorcima. SEM-analiza pokazala je sačuvanu dvofaznu strukturu površine, a EDS-analiza upozorila je na moguća bioaktivna svojstva površine. Zaključak: Ti-Mg kompozit proizveden metodom P/M-a sugerira se kao materijal boljih korozijskih svojstava u usporedbi s čistim titanijem (CP Ti).The innovative titanium-magnesium composite (Ti-Mg) was produced by powder metallurgy (P/M) method and is characterized in terms of corrosion behavior. Material and methods: Two groups of experimental material, 1 mass% (Ti-1Mg) and 2 mass% (Ti-2Mg) of magnesium in titanium matrix, were tested and compared to commercially pure titanium (CP Ti). Immersion test and chemical analysis of four solutions: artificial saliva; artificial saliva pH 4; artificial saliva with fluoride and Hank balanced salt solution were performed after 42 days of immersion, using inductively coupled plasma mass spectrometry (ICP-MS) to detect the amount of released titanium ions (Ti). SEM and EDS analysis were used for surface characterization. Results: The difference between the results from different test solutions was assessed by ANOVA and Newman-Keuls test at p<0.05. The influence of predictor variables was found by multiple regression analysis. The results of the present study revealed a low corrosion rate of titanium from the experimental Ti-Mg group. Up to 46 and 23 times lower dissolution of Ti from Ti-1Mg and Ti-2Mg, respectively was observed compared to the control group. Among the tested solutions, artificial saliva with fluorides exhibited the highest corrosion effect on all specimens tested. SEM micrographs showed preserved dual phase surface structure and EDS analysis suggested a favorable surface bioactivity. Conclusion: In conclusion, Ti-Mg produced by P/M as a material with better corrosion properties when compared to CP Ti is suggested

Water for all : Proceedings of the 7th international scientific and professional conference Water for all

The 7th International Scientific and Professional Conference Water for all is organized to honour the World Water Day by the Josip Juraj Strossmayer University of Osijek, European Hygienic Engineering & Design Group (EHEDG), Danube Parks, Croatian Food Agency, Croatian Water, Faculty of Food Technology Osijek, Faculty of Agriculture in Osijek, Faculty of Civil Engineering Osijek, Josip Juraj Strossmayer University of Osijek Department of Biology, Josip Juraj Strossmayer University of Osijek Department of Chemistry, Nature Park “Kopački rit”, Osijek- Baranja County, Public Health Institute of the Osijek- Baranja County and „Vodovod-Osijek“ -water supply company in Osijek. The topic of World Water Day 2017 was "Wastewater" emphasizing the importance and influence of wastewater treatments on global environment. The international scientific and professional conference Water for all is a gathering of scientists and experts in the field of water management, including chemists, biologists, civil and agriculture engineers, with a goal to remind people about the significance of fresh water and to promote an interdisciplinary approach and sustainability for fresh water resource management. The Conference has been held since 2011. About 300 scientists and engineers submitted 95 abstracts to the 7th International Scientific and Professional Conference Water for all, out of which 33 was presented orally and 62 as posters. 47 full papers were accepted by the Scientific Committee. 38 full papers became the part of the this Proceedings while 9 papers were accepted for publication in Croatian Journal of Food Science and Technology and Electronic Journal of the Faculty of Civil Engineering Osijek - e-GFOS

Synthesis and evaluation of biologically active heterocyclic compounds as corrosion inhibitors

U ovom radu su pripravljeni i ispitani derivati piridina i 1,2,4- triazola kao potencijalni inhibitori korozije aluminija i Al-3Mg legure u 0.5 mol dm-3 i 1 mol dm-3 otopinama HCl. Rezultati mjerenja su pokazali, da svi ispitivani inhibitori znatno utječu na smanjenje procesa korozije, a optimalnu djelotvornost imaju u koncentraciji od 1×10-4 mol dm-3. Ispitivani spojevi A, B i C su netoksični i mogu se rabiti kao inhibitori korozije u prehrambenoj industriji.In this work some derivatives of pyridine and 1,2,4-triazole were prepared and evaluated as potential inhibitors of corrosion of aluminum and Al-3Mg alloy in 0.5 mol dm-3 and 1 mol dm-3 HCl. Obtained results showed that all inhibitors evaluated significantly reduce the corrosion process and optimum efficiency had at concentration of 1 × 10-4 mol dm-3. The tested compounds A, B and C were nontoxic and can be used as corrosion inhibitors in the food industry

The Potential Use of Indigobush (Amorpha fruticosa L.) as Natural Resource of Biologically Active Compounds

Background and Purpose: Recent research indicates that a weed like Indigobush (Amorpha fruticosa L.) gives great opportunities for its commercialization through a rich spectrum of its beneficial biological features with possible use in the forestry and biotechnology field. Therefore, in this study we wanted to explore some of potential application of Indigobush extract, as a source of biologically active compounds, for animal cell culturing as well as green corrosion inhibitors. Materials and Methods: The effect of ethanol extract of Indigobush seeds was studied on human tumor cell lines (HeLa and MCF-7) and cell viability was determined by WST-1 method after 72 hours of treatment with 6 different extract concentrations (0.5-10 mg∙mL-1). The inhibition effect of Indigobush seeds extract on the corrosion of aluminum in 0.5 M hydrochloric acid solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Results: Results showed that the addition of Indigobush extract had a stimulatory effect on MCF-7 cells growth at the concentrations >1 mg∙mL-1 while the same effect on HeLa cells was observed only at the highest concentration of Indigobush extract (10 mg∙mL-1). The stimulatory effect of Indigobush extract on cell viability was more pronounced when the cells were grown in a medium with 5% FBS compared to 10% FBS (v/v). Indigobush extract did not show cytotoxic effect on MCF-7 and HeLa cells. Electrochemical studies showed that with increasing extract concentrations (2.5-15 mg∙mL-1) the values of corrosion current densities decrease, while the polarization resistance values increase. The maximum inhibition efficiency of Indigobush extract is reached at concentration of 15 mg∙mL-1 (82.9%). Conclusions: The Indigobush ethanol extract has no cytotoxic effect on human tumor cell lines MCF-7 and HeLa. Results confirmed that extract originated from Indigobush has the potential to utilize for the mammalian cell culture media formulation by replacing the animal serum. Furthermore, data indicates that Indigobush extract has potential as green alternative to existing synthetic corrosion inhibitors