Analysis of Dielectric Parameters of Fe2O3-Doped Polyvinylidene Fluoride/Poly(methyl methacrylate) Blend Composites.

In this paper, we report the effect of metal oxide (Fe2O3) loading in different weight ratios (0.5%, 1%, 2%, and 4%) on the structural and electrical parameters, viz., the complex dielectric constant, electric modulus spectra, and the AC conductivity, of polymeric composites of PVDF/PMMA (30/70 weight ratio) blend. The structural and geometric measurements have been analyzed with the help of peak location, peak intensity, and peak shape obtained from XRD as well as from FTIR spectra. The electrical properties have been investigated using an impedance analyzer in the frequency range 100 Hz to 1 MHz. The real parts of the complex permittivity and the dielectric loss tangent of these materials are found to be frequency independent in the range from 20 KHz to 1 MHz, but they increase with the increase in the concentration of nano-Fe2O3. The conductivity also increases with an increased loading of Fe2O3 in PVDF/PMMA polymer blends. The electric modulus spectra were used to analyze the relaxation processes associated with the Maxwell-Wagner-Sillars mechanism and chain segmental motion in the polymer mix.

XPS Investigation on Improving Hydrogen Sorption Kinetics of the KSiH3 System by Using Zr-Based Catalysts.

The superior hydrogen storage properties makes the KSiH3 system a potential hydrogen storage material for practical applications. A theoretical capacity of 4.3 wt% bring this material to the front line of all the available hydrogen storage materials; however, the activation barrier of the reaction restricts the system to absorb and desorb hydrogen reversibly at elevated temperatures even if the thermodynamics suggest its room temperature operation. Several catalysts have already been tested to enhance its kinetic properties. In this work, the efforts were made to reduce the activation energy by using Zr-based catalysts to the KSi/KSiH3 system. The value of activation energy was found to be lowest (i.e., 87 kJ mol-1) for the ZrH2-added KSiH3 system. The mechanism of this improvement was investigated by using X-ray photoelectron spectroscopy (XPS).

Pseudo-Binary Phase Diagram of LiNH2-MH (M = Na, K) Eutectic Mixture.

The hunt for a cleaner energy carrier leads us to consider a source that produces no toxic byproducts. One of the targeted alternatives in this approach is hydrogen energy, which, unfortunately, suffers from a lack of efficient storage media. Solid-state hydrogen absorption systems, such as lithium amide (LiNH2) systems, may store up to 6.5 weight percent hydrogen. However, the temperature of hydrogenation and dehydrogenation is too high for practical use. Various molar ratios of LiNH2 with sodium hydride (NaH) and potassium hydride (KH) have been explored in this paper. The temperature of hydrogenation for LiNH2 combined with KH and NaH was found to be substantially lower than the temperature of individual LiNH2. This lower temperature operation of both LiNH2-NaH and LiNH2-KH systems was investigated in depth, and the eutectic melting phenomenon was observed. Systematic thermal studies of this amide-hydride system in different compositions were carried out, which enabled the plotting of a pseudo-binary phase diagram. The occurrence of eutectic interaction increased atomic mobility, which resulted in the kinetic modification followed by an increase in the reactivity of two materials. For these eutectic compositions, i.e., 0.15LiNH2-0.85NaH and 0.25LiNH2-0.75KH, the lowest melting temperature was found to be 307 °C and 235 °C, respectively. Morphological studies were used to investigate and present the detailed mechanism linked with this phenomenon.

Application of in vivo stain of methylene blue as a diagnostic aid in the early detection and screening of oral cancerous and precancerous lesions.

BACKGROUND: Periodic clinical examination of the oral cavity is the mainstay for the early detection of oral cancers which can be further aided by screening individuals with high-risk factors that will identify candidates who should receive treatment to prevent cancer progression and reduce patient mortality. Among the diagnostic tools, in vivo staining is advocated as a simple, inexpensive and fairly sensitive method. MATERIALS AND METHODS: The present study involved the examination of fifty patients suspected of oral malignant or precancerous lesions by methylene blue staining. The results of methylene blue uptake were compared with a simultaneous biopsy of these lesions, while benign epithelial lesions were included as the negative subjects of screening. RESULTS: The results revealed a sensitivity of 89%, a specificity of 91%, a positive predictive value of 97% and a negative predictive value of 73%. CONCLUSION: We recommend that methylene blue staining is a useful diagnostic adjunct in a large, community-based oral cancer screening program for high-risk individuals.

Fibrofascitis - An Enigma for the Dentist: A Case Report.

Fibromyalgia is a chronic syndrome that causes widespread musculoskeletal pain and stiffness throughout the connective tissues that support and move the bones and joints. Pain and localized tender points occur in the muscles, particularly those that support the neck, spine, shoulders, and hips. Moreover the disorder includes fatigue, depression, sleep disturbances and constipation. A combination of treatments including medications, patient education, physical therapy and counseling are usually recommended. Here, we present a case report of fibromyalgia and the treatment given to the patient, a combination of dental and orthopedic treatment.