Preparation of Fe3O4/SiO2/TiO2/CeVO4 Nanocomposites: Investigation of Photocatalytic Effects on Organic Pollutants, Bacterial Environments, and New Potential Therapeutic Candidate Against Cancer Cells

The new nanocomposite with various molar ratios along with magnetic properties was fabricated via precipitation (assisted by ultrasonic) procedure. The photocatalytic effects of methylene blue (∼90% degradation for optimized sample in 100 min) for finding the optimized sample performed under visible light irradiation. Moreover, the photo-antibacterial impacts of bacteria culture environments were found with an optimized sample that had effective destruction of bacteria in comparison to control group. The cytotoxicity properties of panc1 cells and magnetic behaviors of the obtained nanomaterials were evaluated and its IC50 was about 500 mg/L. As an initial step, the structural, morphological and magnetic characteristics of the fabricated nanocomposites were evaluated by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and MAP, UV-visible diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometry (VSM) approaches. Based on SEM results, the size of nanoparticles in fabricated nanocomposite was nearly 50-70 nm for Fe3O4/SiO2/TiO2 and 80-100 nm for Fe3O4/SiO2/TiO2/CeVO4. XRD results showed that desired nanocomposites were truly synthesized without any impurities.

The experimental and theoretical QM/MM study of interaction of chloridazon herbicide with ds-DNA

We report a multispectroscopic, voltammetric and theoretical hybrid of QM/MM study of the interaction between double-stranded DNA containing both adenine-thymine and guanine-cytosine alternating sequences and chloridazon (CHL) herbicide. The electrochemical behavior of CHL was studied by cyclic voltammetry on HMDE, and the interaction of ds-DNA with CHL was investigated by both cathodic differential pulse voltammetry (CDPV) at a hanging mercury drop electrode (HMDE) and anodic differential pulse voltammetry (ADPV) at a glassy carbon electrode (GCE). The constant bonding of CHL-DNA complex that was obtained by UV/vis, CDPV and ADPV was 2.1×10(4), 5.1×10(4) and 2.6×10(4), respectively. The competition fluorescence studies revealed that the CHL quenches the fluorescence of DNA-ethidium bromide complex significantly and the apparent Stern-Volmer quenching constant has been estimated to be 1.71×10(4). Thermal denaturation study of DNA with CHL revealed the ΔTm of 8.0±0.2°C. Thermodynamic parameters, i.e., enthalpy (ΔH), entropy (ΔS°), and Gibbs free energy (ΔG) were 98.45 kJ mol(-1), 406.3 J mol(-1) and -22.627 kJ mol(-1), respectively. The ONIOM, based on the hybridization of QM/MM (DFT, 6.31++G(d,p)/UFF) methodology, was also performed using Gaussian 2003 package. The results revealed that the interaction is base sequence dependent, and the CHL has more interaction with ds-DNA via the GC base sequence. The results revealed that CHL may have an interaction with ds-DNA via the intercalation mode.

Study binding of Al-curcumin complex to ds-DNA, monitoring by multispectroscopic and voltammetric techniques

In this work a complex of Al3+ with curcumin ([Al(curcumin) (EtOH)2](NO3)2) was synthesized and characterized by UV-vis, FT-IR, elemental analysis and spectrophotometric titration techniques. The mole ratio plot revealed a 1:1 complex between Al3+ and curcumin in solution. For binding studies of this complex to calf thymus-DNA various methods such as: UV-vis, fluorescence, circular dichroism (CD), FT-IR spectroscopy and cyclic voltammetry were used. The intrinsic binding constant of ACC with DNA at 25°C was calculated by UV-vis and cyclic voltammetry as 2.1×10(4) and 2.6×10(4), respectively. The thermodynamic studies showed that the reaction is enthalpy and entropy favored. The CD results showed that only the Δ-ACC interacts with DNA and the Δ-ACC form has not any tendency to interact with DNA, also the pure curcumin has not any stereoselective interaction with CT-DNA. Fluorimetric studies showed that fluorescence enhancement was initiated by a static process in the ground state. The cyclic voltammetry showed that ACC interact with DNA with a binding site size of 2. From the FT-IR we concluded that the Δ-ACC interacts with DNA via partial electrostatic and minor groove binding. In comparison with previous works it was concluded that curcumin significantly reduced the affinity of Al3+ to the DNA.

Chemical composition and antioxidant activity of the essential oil and various extracts of Haplophyllum robustum Bge

This study was designed to examine the chemical composition and in vitro antioxidant activity of the essential oil and various extracts of Haplophyllum robustum. GC-MS analysis of the oil resulted in the identification of 30 compounds, representing 99.2% of the oil; 1,8-cineole (38.1%), myrcene (10.7%), α-pinene (8.5%), 4-terpineol (7.0%) and sabinene (6.1%) were the main components. The antioxidant potential of the oil and extracts was evaluated using three separate methods: inhibition of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene-linoleic acid assay and reducing power systems. The essential oil of the plant was able to reduce the stable free radical DPPH with an IC(50) of 72.0 ± 1.2 µg mL(-1) (the IC(50) for ascorbic acid was determined as 5.8 ± 0.4 µg mL(-1)). The essential oil also showed strong reducing power. The level of total phenolics was highest in the essential oil (179.5 ± 2.1 µg mg(-1)).

Effect of nitrate content on thermal decomposition of nitrocellulose

Data on the thermal stability of energetic materials such as nitrocellulose was required in order to obtain safety information for handling, storage and use. In the present study, the thermal stability of four nitrocellulose samples containing various amount of nitrate groups was determined by differential scanning calorimetery (DSC) and simultaneous thermogravimetery-differential thermal analysis (TG-DTA) techniques. The results of TG analysis revealed that the main thermal degradation for the nitrocellulose occurs in the temperature ranges of 192-209 degrees C. On the other hand, the TG-DTA analysis of compounds indicates that nitrate content of nitrocellulose could has affect on its thermal stability and its decomposition temperature decrease by increasing its nitrogen percent. The influence of the heating rate (5, 10, 15 and 20 degrees C/min) on the DSC behaviour of the nitrocellulose was verified. The results showed that, as the heating rate was increased, decomposition temperature of the compound was increased. Also, the kinetic parameters such as activation energy and frequency factor for the compound was obtained from the DSC data by non-isothermal methods proposed by ASTM E696 and Ozawa.