Cobalt OXIDE/ ZINC OXIDE nanocomposite was synthesized by dropwise addition of Co(NO)3.6H2O and Zn(NO3)2.4H2O solutions to KOH solution at different temperatures followed by calcination at 300oC for 4 h. The morphology and structure of nanoparticles and the influence of temperature on particle size were studied using scanning electron microscopy (SEM) and X-Ray Diffraction (XRD). Minimum particle size was obtained before calcination at 70oC. In addition, the spherical, semispherical and flake-shaped nanoparticles were observed at ambient temperature. On the other hand, Co(OH)2 was transformed to Co3O4, ZnO flakes were eliminated, and particle size changed during calcination. Synthesized samples at 50oC and 70oC showed an increase size after calcinations; however, elimination of flakes during calcination caused particle size reduction for synthesized sample at ambient temperature.

ZINC OXIDE nano particles have many applications including food, medicine, tube and electronic industries. ZINC OXIDE nano powder can be produced using new and different methods. In this study precipitation transformation method was used to produce ZINC nano OXIDE from concentrated OXIDE of Angoran mine in Zanjan Province of Iran. At first, acidic leaching, neutral leaching, hot and cold purification were carried out and then the final product of to ZnSO4 precipitation method in order to ZnO nano powder was used. Six parameters such temperature, time, mixing rate and NaOH, Na2CO3 and ZnSO4 concentrations in four levels were employed for the experimental design. The optimum condition were found when the Na2CO3 solution and NaOH had the concentration of 1M at the temperature of 8000 C and the time and mixing rate were not much effect on production of nano powder. Then NaOH solution was dropped into the precursor. The final production was the ZINC OXIDE nano sized. Then ZnO nano powder is variable in size from 70nm to 150nm.

Background: Candidiasis is the most common fungal infection in human and warm-blooded animals. Candida albicans, is an opportunistic pathogen in immune suppressed hosts, like HIV infected and under chemotherapy patients. Since, antifungal drugs are limited and challenged by resistance. Thus discovering agents with antifungal properties and minimum side effects and toxicity is essential. Nano-agents such as metal OXIDE nano-particles have unique properties such as high surface to volume ratio that introduce them as appropriate antimicrobial agents.Materials and Methods: In this experimental study, antifungal effects of 4 nano-metal OXIDEs; magnesium OXIDE, ZINC OXIDE, silicon OXIDE and copper OXIDE (MgO, SiO2, ZnO and CuO) were investigated in vitro against Candida albicans and compared with amphotericin B. Solution acetic acid was used for preparing nanoparticles suspensions. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of these nano-particles were evaluated.Results: The results showed that MIC of nano-MgO and nano SiO2 was greater than 3200 mg/mL, but MIC and MFC of nano-ZnO was recorded 200 mg/mL and 400 μg/mL, respectively. The MIC and MFC of nano-CuO was 400 mg/mL. The MIC and MFC of amphotericin B was 0.5 mg/mL and 2 mg/mL, respectively.Conclusions: It is concluded that, ZnO and CuO nanoparticles have anti C. albicans properties and may be used in treatment of infections caused by this fungus that should be investigated in vivo.

ZINC OXIDE nanoparticles (ZnO-NPs) and graphene carbon material, due to lower drug resistance, can replace antibiotics, and by decorating of graphene with Zn-NPs, their properties can be greatly improved. The purpose of this study was to evaluate the antioxidant and antibacterial effects of ZnO-NPs biosynthesized using Crocus Sativus petal extract, graphene and graphene decorated by ZnO-NPs biosynthesized using Crocus Sativus petal extract (G-ZnO). Their physicochemical characterizations were performed by UV-Vis spectroscopy, Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM), revealing that ZnO-NPs with a mean size of 25 nm and spherical-shape were distributed uniformly on the surface of the graphene without aggregation. The antioxidant activities of ZnO-NPs, graphene and G-ZnO were evaluated using DPPH and ABTS assays. Antibacterial activities of three compounds were tested against Gram negative bacteria Escherichia coli (E. coli) and Gram positive bacteria Staphylococcus aureus (S. aureus) using macrodilution method. The results of this study showed that these three compounds have antioxidant and antibacterial effects. And it was show that but also antioxidant and antibacterial activity of G-ZnO was higher than ZnO-NPs and graphene. G-ZnO could be useful as a natural antioxidant and antibacterial in the pharmacy industry.

Nanostructured metal OXIDEs received considerable research attention due to their unique properties that can be used for designing advanced nanodevices. Thus, in the present study, ZINC OXIDE/graphene OXIDE (ZnO/GO) nanocomposite was synthesized, characterized and implemented in an electrochemical system. The formation of a compacted ZnO/GO nanocomposite was confirmed by field emission scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and attenuated total reflectance spectroscopy.HRTEM showed that ZnO nanocrystals (NCs) are well formed on the GO surface and are interconnected via GO functional groups. From the XRD patterns, the average size of ZnO NCs was found to be about 21.7± 2.3 nm which is in agreement with the HRTEM results. The newly developed nanocomposite-based electrochemical system showed a significant improvement in both electrical conductivity and the electrocatalytic activity as noted from the cyclic voltammetry measurements.Consequently, direct electron transfer efficiency was confirmed and used for the amperometric detection of hydrogen perOXIDE (H2O2). Fast and sensitive electrochemical responses for the detection of H2O2 at 1.1 V in the linear response range from 1 to 15 mM with the detection limit (S/N=3) of 0.8 mM were obtained. These results demonstrated that the prepared ZnO/GO/CPE displayed a good performance along with high sensitivity and longterm stability.