The Significance of Buffer Solutions on Corrosion Processes of Cobalt Ferrite CoFe2O4 Thin Film on Different Substrates.

BACKGROUND: The spinel ferrite nanoparticles, such as zinc, nickel, and cobalt ferrites have exceptional electronic and magnetic properties. Cobalt ferrite nanomaterial (CoFe2O4) is a hard material that reveals high magnetic, mechanical, and chemical stability. AIM AND OBJECTIVE: The objective of this research is to predict the corrosion behavior of cobalt ferrite (CoFe2O4) thin films deposited on different substrates (platinum Pt, stainless steel S.S, and copper Cu) in acidic, neutral, and alkaline medium. MATERIALS AND METHODS: Cobalt ferrite thin films were deposited on platinum, stainless steel, and copper via electrodeposition-anodization process. After that, corrosion resistance of the prepared nanocrystalline cobalt ferrite on different substrates was investigated in acidic, neutral, and alkaline medium using open circuit potential and potentiodynamic polarization measurements. The crystal structure, crystallite size, microstructure, and magnetic properties of the ferrite films were investigated using a combination of XRD, SEM and VSM. RESULTS: The results of XRD revealed a cubic spinel for the prepared cobalt ferrite CoFe2O4. The average size of crystallites was found to be about 43, 77, and 102 nm precipitated on platinum, stainless steel, and copper respectively. The magnetic properties of which were enhanced by rising the temperature. The sample annealed at 800oC is suitable for practical application as it showed high magnetization saturation and low coercivity. The corrosion resistance of these films depends on the pH of the medium as well as the presence of oxidizing agent. CONCLUSION: Depending on the obtained corrosion rate, we can recommend that, CoFe2O4 thin film can be used safely in aqueous media in neutral and alkaline atmospheres for Pt and Cu substrates, but it can be used in all pH values for S.S. substrate.

Assessment of hepatic function, oxidant/antioxidant status, and histopathological changes in rats treated with atorvastatin: Effect of dose and acute intoxication with acetaminophen.

A major disadvantage that may occur in association with atorvastatin (ATV) therapy is elevation of serum transaminases. This study was designed to evaluate the effects of treatment of rats with various doses of ATV (2, 5, and 10 mg/kg/day) on liver function, oxidative stress, and histology and on the severity of acetaminophen (APAP) hepatotoxicity. ATV administration for 21 days resulted in a dose-dependent significant rise in serum activities of alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase. Only ATV at 10 mg/kg/day decreased reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity, increased malondialdehyde (MDA) levels, and elicited histopathological changes in the liver. In rats challenged with APAP (500 mg/kg), the livers showed centrilobular necrosis with evident oxidative stress and liver dysfunction after 24 h. Rats challenged with APAP after pretreatment with ATV 2 or 5 mg/kg/day showed significantly lower activities of serum enzymes, higher hepatic GSH levels and SOD activities, lower MDA levels and milder histopathological changes compared with rats challenged with APAP after pretreatment with ATV 10 mg/kg/day or without drug pretreatment. In conclusion, the effect of ATV on the liver is dose dependent. Our results showed that ATV, at the highest dose used, induced hepatic lipid peroxidation and injury, suggesting a role for oxidative stress in ATV-induced hepatotoxicity. However, lower doses of ATV attenuated APAP-induced hepatotoxicity via a mechanism related, at least in part, to a reduction of APAP-induced hepatic oxidative stress. These results are of practical interest as both drugs may be used concurrently in clinical practice.

Nanotoxicity of gold and gold-cobalt nanoalloy.

Nanotoxicology test of gold nanoparticles (Au NPs) and gold-cobalt (Au-Co) nanoalloy is an important step in their safety evaluation for biomedical applications. The Au and Au-Co NPs were prepared by reducing the metal ions using sodium borohydride (NaBH(4)) in the presence of polyvinyl pyrrolidone (PVP) as a capping material. The average size and shape of the nanoparticles (NPs) were characterized using high resolution transmission electron microscopy (HRTEM). Cobalt presence in the nanoalloy was confirmed by energy dispersive X-ray spectroscopy (EDX) analysis, and the magnetic properties of these particles were determined using a vibrating sample magnetometer (VSM). The Gold and gold-cobalt NPs of average size 15 ± 1.5 nm were administered orally to mice with a dose of 80, 160, and 320 mg/kg per body weight (bw) using gavages. Samples were collected after 7 and 14 days of the treatment. The results indicated that the Au-Co NPs were able to induce significant alteration in the tumor-initiating genes associated with an increase of micronuclei (MNs) formation and generation of DNA adduct (8-hydroxy-2-deoxyguanosine, 8-OHdG) as well as a reduction in the glutathione peroxidase activity. This action of Au-Co NPs was observed using 160 and 320 mg/kg bw at both time intervals. However, Au NPs had much lower effects than Au-Co NPs on alteration in the tumor-initiating genes, frequency of MNs, and generation of 8-OHdG as well as glutathione peroxidase activity except with the highest dose of Au NPs. This study suggests that the potential to cause in vivo genetic and antioxidant enzyme alterations due to the treatment by Au-Co nanoalloy may be attributed to the increase in oxidative stress in mice.

Pollination mutualism between Alocasia macrorrhizos (Araceae) and two taxonomically undescribed Colocasiomyia species (Diptera: Drosophilidae) in Sabah, Borneo.

Two taxonomically undescribed Colocasiomyia species were discovered from inflorescences of Alocasia macrorrhizos in Kota Kinabalu City, Sabah, Borneo, Malaysia. The aims of this study were to investigate the reproductive ecology of the flies and the plant, ascertain the importance of the flies as pollinators and examine the intimate association between flowering events and life history of the flies. We conducted sampling, observations and field pollination experiments. The flies were attracted by the odour of female-phase inflorescences in the early morning on the first day of anthesis. They fed, mated and oviposited in the inflorescences for 1 day. On the second day, the flies, covered with pollen grains, left the male-phase inflorescences for the next female-phase inflorescences. The immature forms of both fly species hatched, developed and pupated within the infructescences without damaging the fruits, and developed adults emerged when the mature infructescences dehisced. The flowering events and fly behaviours were well synchronized. In field pollination experiments, inflorescences bagged with a fine mesh (insect exclusion) produced almost no fruits, whereas those bagged with a coarse mesh (bee exclusion) produced as many fruits as the open-pollinated controls. These results indicate that these flies are the most efficient and specialised pollinators for their host, A. macrorrhizos. These flies, in return, depend on A. macrorrhizos for food and habitat through most of their life cycle. This study provides a deeper insight into the less recognised, highly intimate pollination mutualism between Araceae plants and Colocasiomyia flies.

Intramedullary pyogenic abscess in the conus medullaris.

Primary pyogenic abscess in the conus medullaris in a healthy adult has never been reported. An urgent MRI scan with contrast and prompt surgical evacuation may lead to good neurological recovery.

Genotoxicity evaluation of nanomaterials: dna damage, micronuclei, and 8-hydroxy-2-deoxyguanosine induced by magnetic doped CdSe quantum dots in male mice.

Quantum dots (QDs) are a novel class of inorganic fluorophores which are gaining widespread recognition as a result of their exceptional photophysical properties and their applications as a biomarker and in molecular biomedical imaging. The aim of this study was to evaluate the in vivo genotoxicity in mice exposed to CdSe quantum dots of average size 5.0 ± 0.2 nm and CdSe doped with 1% cobalt ions of similar size. The quantum dots are surface modified using mercaptoacetic acid (MAA) in order to be biocompatible and water-soluble. The MAA-QDs were given to the mice orally at doses of 500, 1000, and 2000 mg/kg by weight of MAA-QDs. Bone marrow and liver samples were collected after two and seven days of treatment. The results indicated that after two days of treatment, the high dose of doped MAA-QDs was significantly able to induce DNA damage, formation of micronuclei (MNs), and generation of DNA adduct (8-hydroxy-2-deoxyguanosine, 8-OHdG). However, increasing DNA damage and the frequency of MNs formation as well as the generation of DNA adducts were observed with both the undoped MAA-QDs (2000 mg/kg) and doped MAA-QDs (1000 and 2000 mg/kg) after seven days of treatment. The results of our study indicate that exposure to high doses of pure MAA-QDs or MAA-QDs doped with cobalt has the potential to cause indirect in vivo genetic damage, which may be attributed to free radical-induced oxidative stress in mice.