Photodynamic and antibacterial studies of template-assisted Fe2O3-TiO2 nanocomposites.

Fe2O3-TiO2 (FT) nanocomposites were successfully synthesized by template-assisted precipitation reaction using Polyvinylpyrrolidone-Polyethylene glycol (PVP-PEG), Tween-80 (T-80) and Cetyltrimethylammomium bromide (CTAB) as templates. The prepared nanocomposites were characterized by XRD, SEM, EDX, UV-DRS, FT-IR, and FT-Raman spectroscopic analysis. The photohemolysis studies were done in human erythrocytes and the cell viability studies were done in HeLa cell lines under the irradiation of an LED light source. The photodynamic studies were performed under two different experimental conditions, such as varying concentrations as well as a time of irradiation. The nanocomposites exhibit significant photodynamic activity via the generation of reactive oxygen species (ROS) under the light source. The results show that the PVP-PEG-assisted Fe2O3-TiO2 (FT-PVP-PEG) nanocomposite has more potential for photodynamic activity in the presence of an LED light source. Also, the antibacterial effect of the samples was investigated against gram-negative bacteria (Escherichia coli). Among all nanocomposites, FT-PVP-PEG shows remarkable antibacterial activity against E. coli. Moreover, the template-assisted nanocomposites protect the biomolecules from the toxicity generated by the magnetic nanoparticles (NPs). The template-assisted FT nanocomposites for the field of photodynamic activity have been experimentally shown for the first time.

Enhanced photocatalytic and photodynamic activity of chitosan and garlic loaded CdO-TiO2 hybrid bionanomaterials.

Herein, the work addresses the synthesis of biomaterials (chitosan and garlic) loaded CdO-TiO2 hybrid nanocomposites for photocatalytic water treatment and photodynamic cancer therapeutic applications that were reported the first time. CdO-TiO2 (CT) nanocomposites were synthesized and loaded with the biomaterials such as chitosan and garlic by simple sol-gel method. The nanomaterials were characterized and the photodegradation of three model pollutants, Methylene blue (MB), Methyl orange (MO) and Rhodamine B (Rh-B) was opted to investigate the efficiency of the synthesized photocatalyst under the solar light. From the results, the garlic-loaded CdO-TiO2 (AS-CT) hybrid nanocomposites exhibit a superior photocatalytic activity than the chitosan-loaded CdO-TiO2 (CS-CT) and CdO-TiO2 (CT) nanocomposites under the irradiation of solar light. Additionally, the cell viability of the synthesized nanocomposites was carried out in HeLa cell lines under different concentrations, light doses and incubation periods using an LED light source. Compared to the CS-CT and CT nanocomposites, an efficient photodynamic activity was achieved in the case of AS-CT hybrid nanocomposites. Actually, the end-use properties required for both processes in AS-CT nanocomposites appear similar due to the presence of organo sulphurus compounds.

Synergistic effect of ultrasonication and phase transfer catalysts in radical polymerization of methyl methacrylate - A kinetic study.

Methyl methacrylate (MMA) has been polymerized to poly methyl methacrylate (PMMA) by employing three different phase transfer catalysts (PTC) such as 1,4-bis(dimethylhexyl)ethylenediammoniumbromide (DMHEDAB), 1,4bis(dimethylheptyl)ethylenediammoniumbromide (DMH1EDAB) and 1,4-bis(dimethyloctyl)ethylenediammonium bromide (DMOEDAB) under the influence of ultrasound radiation. The radical polymerization was performed under unstirred condition at a temperature of 60±1°C in an oxygen free atmosphere employing water soluble K2S2O8 as initiator. Various parameters such as role of [Monomer], [Initiator], [PTC], solvent and temperature were investigated on rate of polymerization (Rp) and the synergic efficacy of ultrasound wave variation and phase transfer catalysts were also assessed. It was found that the rate of polymerization (Rp) increased drastically for all the three catalyst under the influence of ultrasound and the order of efficiency was found to be [Formula: see text] This increase may be due to the number of carbon chain attached to the polar group which facilitate and accelerate the rate of polymerization.

A study on stability analysis of atrial repolarization variability using ARX model in sinus rhythm and atrial tachycardia ECGs.

BACKGROUND: The interaction between the PTa and PP interval dynamics from the surface ECG is seldom explained. Mathematical modeling of these intervals is of interest in finding the relationship between the heart rate and repolarization variability. OBJECTIVE: The goal of this paper is to assess the bounded input bounded output (BIBO) stability in PTa interval (PTaI) dynamics using autoregressive exogenous (ARX) model and to investigate the reason for causing instability in the atrial repolarization process. METHODS: Twenty-five male subjects in normal sinus rhythm (NSR) and ten male subjects experiencing atrial tachycardia (AT) were included in this study. Five minute long, modified limb lead (MLL) ECGs were recorded with an EDAN SE-1010 PC ECG system. The number of minute ECGs with unstable segments (Nus) and the frequency of premature activation (PA) (i.e. atrial activation) were counted for each ECG recording and compared between AT and NSR subjects. RESULTS: The instability in PTaI dynamics was quantified by measuring the numbers of unstable segments in ECG data for each subject. The unstable segments in the PTaI dynamics were associated with the frequency of PA. The presence of PA is not the only factor causing the instability in PTaI dynamics in NSR subjects, and it is found that the cause of instability is mainly due to the heart rate variability (HRV). CONCLUSION: The ARX model showed better prediction of PTa interval dynamics in both groups. The frequency of PA is significantly higher in AT patients than NSR subjects. A more complex model is needed to better identify and characterize healthy heart dynamics.

Synthesis and characterization of zinc oxide-neem oil-chitosan bionanocomposite for food packaging application.

Nano zinc oxide at different concentrations (0.1, 0.3 and 0.5%) and neem essential oil were incorporated into the chitosan polymer by solution cast method to enhance the properties of the bionanocomposite film. The functional groups, crystalline particle size, thermal stability and morphology were determined using FTIR, XRD, TGA and SEM, respectively. The results showed that 0.5% nano zinc oxide incorporated composite film have improved tensile strength, elongation, film thickness, film transparency and decreased water solubility, swelling and barrier properties due to the presence of neem oil and nano zinc oxide in the polymer matrix. Further antibacterial activity by well diffusion assay method was followed against Escherichia coli which were found to have good inhibition effect. In addition to this food quality application were carried against carrot and compared with the commercial film.

Simple phytosynthesis and humidity sensing application of biocomposite doped nanocrystalline magnesium oxide.

In the present work, we report simple and eco-friendly route to synthesise biocomposite doped nanocrystalline MgO. The seed of Hygrophila spinosa T. Anders (HST) plant showing gelly nature in water and contain several minerals, is the chosen dopant (biocomposite). The structural parameters, functional groups, surface morphology, elemental analysis and optical behavior of the prepared samples were evaluated by using X-ray diffraction (XRD), Fourier transform-infra red (FT-IR), high resolution scanning electron microscope (HR-SEM), Energy dispersive X-ray analysis (EDX), Diffuse reflectance spectroscopy (DRS) techniques respectively. The two probe DC-electrical resistance method was used to evaluate the sensitivity factor (S(f)) of the prepared samples at different humidity levels. It was found that the appropriate ratio of dopant into MgO extensively modified the sensitivity. Compared to all the other composition of Mg:HS, the sensitivity factor (S(f)) of MH3 (0.25:0.75) is found to be higher i.e., 3,300. The MH3 sample also showed good linearity, reproducibility, stability, response and recovery time about 210 +/- 5 s and 232 +/- 4 s, respectively. The composition, crystallite size and surface area were found to have the significant effects on the sensitivity.