Search

Non‐isothermal thermogravimetric analysis in air, of polyoctenamer‐single wall carbon nanotubes (PO‐SWNTs), loaded by various amounts of SWNTs up to 10% wt., at different heating rates (ranging from 5 to 40°C/min) is reported. The thermal degradation in the air of PO_SWNTs is dominated by a main single sigmoidal dependence, assigned to the polymer and eventually polymer‐nanofiller interphase, over which a weaker sigmoid assigned to the thermo‐oxidative degradation of the nanofiller is superimposed at higher temperatures. The temperature at which the nanocomposite's residual mass fraction reaches x% wt. of the initial mass, Tx%, is reported (for x = 5, 50, and 85). The dependence of Tx% on the heating rate and the loading by nanotubes is analyzed. The temperature derivative of the thermograms defines new parameters (inflection residual mass fraction and inflection temperature) and (degradation) width. Their dependence on the loading by SWNTs was reported. Estimation of the interphase in polymer‐based nanocomposites is based on the postulate that the dependence of the inflection temperature on the composition of the nanocomposite obeys a Fox‐like dependence, where the bulk polymer and the polymer trapped within the interphase are considered as a blend of two miscible polymers. Complementary Raman, x‐ray diffraction, and differential scanning calorimetry support these results. [ABSTRACT FROM AUTHOR]

Drug dependence is a chronic relapsing condition. Management of drug dependence remains at early phases in context of Nepal. Methadone maintenance treatment program is one of the therapies aimed at preventing relapses. Thus this study aimed to examine the socio-demographic and behavioral characteristics and determinants in cases of psychoactive drug dependence and relapses. Fifty patients with Opiate dependence who presented to MMTP were studied. Descriptive, cross sectional study was done at MMTP of Patan Mental Hospital. Twentieth version of Statistical package for social science (SPSS-20) was used to analyze data. Among clients enrolled in the study, majority (82%) were young and mid-aged. 90% belonged to middle or high income groups. Relapses were commonly found in mid-aged people (70% were between 31 to 50 years). In 80% of cases relapses were frequent. People using psychoactive substances experience frequent relapses. Pattern of use of these substances have shifted to more harder and synthetic products. MMTP was started as part of managing drug dependence and relapses. [ABSTRACT FROM AUTHOR]

Polymer-matrix nanocomposites based on Poly(lactic-co-glycolic) acid (PLGA) and Graphene platelets (GNPs) were studied. GNPs, nanomaterials with a 2D flat surface, were chosen with or without chemical modification in PLGA/GNP nanocomposites and their microstructure, thermal property, and their compatibility as scaffolds for cell growth were investigated. PLGA/GNP nanocomposites (0, 1, and 5wt.% of GNPs) were prepared using a solution based technique. Transmission electron microscopy, X-ray diffraction, Differential scanning calorimeter, and Thermogravimetric analyzer were used to analyze morphology and thermal properties. This work demonstrated the role of GNPs flat surface to provide a favorable platform resulting in an enhanced PLGA crystallization. Functionalized GNPs suppress both the thermal stability and the crystallization of PLGA. Finally, to determine the potential usefulness of these scaffolds for biomedical applications, mammalian cells were cultured on various PLGA/GNP nanocomposites (0, 1, and 5wt.% GNPs). 1wt.% PLGA/GNP nanocomposites showed better biocompatibility for cell growth with/without graphenes functionalization compared to pure PLGA and 5wt.% PLGA/GNP. The function of GNPs in PLGA/GNPs (1wt.%) composites is to provide a stage for PLGA crystallization where cell growth is favored. These results provide strong evidence for a new class of materials that could be important for biomedical applications. [ABSTRACT FROM AUTHOR]

In this work, the effect of different ions (hydrogen, helium, and neon) implanted on single-walled carbon nanotube (SWNT) is being analyzed using thermogravimetric analysis (TGA), Raman scattering, and x-ray photoelectron spectroscopy (XPS). The TGA result shows that the temperature for maximum decomposition rate (Tmax) increases at relatively low doses, i.e., by about 30 °C after hydrogen ion implantation (at the ion dose of 1015 cm-2), 17 °C after helium ion implantation (at the ion dose of 1013 cm-2), and contributes no significant enhancement after neon implantation for all doses. The increase of Tmax indicates that small mass ion can be utilized to improve the thermal-oxidative stability of SWNTs. Raman scattering and XPS were used to monitor the lattice damage from ion implantation and chemical bonding states of the materials. The results indicated the material rigidity for low doses of hydrogen and helium, while the application of higher doses of neon caused the material to transform towards amorphous carbon (a-C). [ABSTRACT FROM AUTHOR]

Greater indulgence into use of nicotine either via smoked or smokeless form in patients with schizophrenia has been accounted in literature numerous times. Prevalence studies of use and dependence of nicotine are less. Thus this study aimed to find more about use and dependence of nicotine and readiness to quit among schizophrenic patients. Ninety seven patients with Schizophrenia were studied. A hospital based, descriptive, cross sectional study was done at Department of Psychiatry, Tribhuvan University Teaching Hospital (TUTH). To screen the nicotine users WHO STEPS was used. For smokers Fagerström Test for Nicotine Dependence was used and for smokeless tobacco users Modified Fagerström-Smokeless Tobacco was used. Assessment of Motivation: Readiness to Quit Ladder was applied to assess motivation. Twentieth version of Statistical package for social science (SPSS-20) was used to analyze data. Among 97 patients enrolled in the study, 55.7% used tobacco in one form or the other. Smoked tobacco only was used by 50% whereas 27.8% used both somokeless and smoked tobacco. Moderate nicotine dependence was found in 77.7% of smokers whereas 53.3% of combined users were highly dependent. Readiness to quit median value was four. It was found to be statistically significant (p<0.05). It was found that in schizophrenics prevalence of nicotine use and dependence is high. Increased tendency to retain nicotine using habits was seen when both smoked and smokeless tobacco were consumed. [ABSTRACT FROM AUTHOR]

The effect of carbon nanofibers on the crystallization of polyethylene using differential scanning calorimetry operating in dynamical mode at various cooling rates (2, 4, 8, 15, and 30°C/min) is reported. Experimental data were analyzed using the Avrami, Ozawa, and the combined Avrami–Ozawa methods. It is concluded that the addition of carbon nanofibers modifies the crystallization process of polyethylene (changing the value of the Avrami exponent), and that the combined Avrami–Ozawa approach describes more accurately the crystallization of carbon nanofiber reinforced polyethylene composites. The analysis of the experimental data indicates that the dispersion of carbon nanofibers within polyethylene leads to complex changes in the crystallization process such as increased crystallization temperature, longer times to reach 50% crystallization, higher crystallization rates, and lower degrees of crystallinity of the polymeric component. [ABSTRACT FROM AUTHOR]