Effect of stabilizer content in different solvents on the synthesis of ZnO nanoparticles using the chemical precipitation method.

Zinc Oxide (ZnO) nanoparticles (NPs) have been synthesized by a simple chemical precipitation method. The effect of monoethanolamine (MEA) content in different solvents on ZnO NPs synthesis and their structural properties has been investigated. The NPs synthesized by using isopropanol (IPA) with 15 ml MEA as a stabilizer under the most favorable conditions (deposition time, td = 120 min, temperature = 60 °C) showed good structural properties. Synthesized NPs exhibited beneficial structural properties after annealing. The hexagonal wurtzite crystal structure of ZnO NPs was verified by XRD. Different models were used to calculate structural parameters such as crystallite size, strain, stress, and energy density for all the reflection peaks of XRD corresponding to ZnO lying in the range 2θ = 15°-80°. The crystallite size of the ZnO nanoparticles was found to be 50-60 nm. FTIR and EDX confirmed the presence of ZnO NPs in the samples. SEM micrograph of all the samples revealed that the grain sizes decrease gradually with the increase of the amount of MEA. UV-Visible diffuse reflectance spectroscopy results provide evidence that the ZnO NPs possess broader absorption bands, together with high band gap energy. The ZnO NPs synthesized with IPA solvent have the highest transmittance and band gap energy of 3.3eV. According to DLS data, various content of MEA stabilizer in solvent affects the hydrodynamic size of ZnO NPs.

Vacancy-Induced Temperature-Dependent Thermal and Magnetic Properties of Holmium-Substituted Bismuth Ferrite Nanoparticle Compacts.

Multiferroics have gained widespread acceptance for room-temperature applications such as in spintronics, ferroelectric random access memory, and transistors because of their intrinsic magnetic and ferroelectric coupling. However, a comprehensive study, establishing a correlation between the magnetic and thermal transport properties of multiferroics, is still missing from the literature. To fill the void, this work reports the temperature-dependent thermal and magnetic properties of holmium-substituted bismuth ferrite (BiFeO3) and their dependencies on oxygen vacancies and structural modifications. Two distinct magnetic transitions on temperature-dependent magnetic and heat capacity responses are identified. Experimental analysis suggests that the excess of oxygen vacancies shifts the magnetic transition temperature by ∼64 K. The holmium substitution-induced structural modification increases BiFeO3 heat capacity by 30% up to the antiferromagnetic phase transition temperature. Furthermore, an unsaturated heat capacity even at temperatures as high as 850 K is observed and is ascribed to anharmonicity and partial densification of the nanoparticles used during heat capacity measurements. The room-temperature thermal conductivity of BiFeO3 is ∼0.33 ± 0.11 W m-1 K-1 and remains unchanged at high temperatures due to defect scattering from porosities.

Depression among Patients Presenting with Gastrointestinal Symptoms: Prevalence and Associated Factors.

Gastrointestinal diseases frequently affect patients' physical and emotional wellbeing as being heavily affected by stress. This study was conducted to find out prevalence and severity of depressive symptoms among patients presenting with gastrointestinal symptoms. This cross sectional study was conducted at Outpatients Department jointly by Department of Gastroenterology and Department of Psychiatry of a tertiary care hospital in north east part of Bangladesh from November 2011 to June 2012. Consecutive patients with gastrointestinal symptoms underwent psychiatric evaluation using HDRS and analyzed. 442 patients, 38(8.6%) were found normal. Among the rest 128(28.96%), 138(31.22%), 72(16.29%) and 66(14.93%) had mild, moderate, severe and very severe depressive symptoms respectively. Female sex (95.03% vs. 89.32%), married people (93.77 vs. 86.13%), older age (98.24%), rural people (94.26% vs. 84.36%), farmers (96.36%) and house wives (96.24%) were more affected. Prevalence of depression was also higher among patients with lower socioeconomic class, less educated people and rural background. Depressive symptoms are very common in patients presenting with gastrointestinal symptoms. Awareness regarding psychiatric assessment and intervention may reduce sufferings and thus improve wellbeing of these patients.

Bi0.9Ho0.1FeO3/TiO2 Composite Thin Films: Synthesis and Study of Optical, Electrical and Magnetic Properties.

A visible light active Bi0.9Ho0.1FeO3 nanoparticles/TiO2 composite thin films with different mol.% of Bi0.9Ho0.1FeO3 were successfully prepared via non-aqueous sol-gel method. The incorporation of 5, 10 and 20 mol.% Bi0.9Ho0.1FeO3 nanoparticles in the precursor solution of TiO2 brings modifications in the functional properties of the composite thin films. XPS analysis indicates that interdiffusion of Fe3+, Ho3+, Bi3+/Ti4+ ions through the interfaces between Bi0.9Ho0.1FeO3 nanoparticles and TiO2 matrix reduces the concentration of Ti3+ ions. X-ray diffraction analysis affirms that TiO2 and Bi0.9Ho0.1FeO3 retain anatase and orthorhombic phase respectively in composite films. The composite thin film containing 20 mol.% Bi0.9Ho0.1FeO3 nanoparticles exhibits the most prominent absorption phenomenon in visible region and has significantly reduced indirect band gap of 2.46 eV compared to that of pure TiO2 (3.4 eV). Hall effect measurements confirm that the resistivity of composite film increases by ∼2.33 orders of magnitude and its carrier concentration decreases by 1.8 orders of magnitude at 5 mol.% Bi0.9Ho0.1FeO3 nanoparticles addition compared to those of pure TiO2 film. Moreover, the pure film exhibits diamagnetism, whereas the composite films have both large ferromagnetic and small diamagnetic components. The findings in this research justify that the composite film can be a potential candidate for making improved photocatalyst, resistors and spintronic devices.

Consensus Recommendation for India and Bangladesh for the Use of Pneumococcal Vaccine in Mass Gatherings with Special Reference to Hajj Pilgrims.

Respiratory tract infections are prevalent among Hajj pilgrims with pneumonia being a leading cause of hospitalization. Streptococcus pneumoniae is a common pathogen isolated from patients with pneumonia and respiratory tract infections during Hajj. There is a significant burden of pneumococcal disease in India, which can be prevented. Guidelines for preventive measures and adult immunization have been published in India, but the implementation of the guidelines is low. Data from Bangladesh are available about significant mortality due to respiratory infections; however, literature regarding guidelines for adult immunization is limited. There is a need for extensive awareness programs across India and Bangladesh. Hence, there was a general consensus about the necessity for a rapid and urgent implementation of measures to prevent respiratory infections in pilgrims traveling to Hajj. About ten countries have developed recommendations for pneumococcal vaccination in Hajj pilgrims: France, the USA, Kuwait, Qatar, Bahrain, the UAE (Dubai Health Authority), Singapore, Malaysia, Egypt, and Indonesia. At any given point whether it is Hajj or Umrah, more than a million people are present in the holy places of Mecca and Madina. Therefore, the preventive measures taken for Hajj apply for Umrah as well. This document puts forward the consensus recommendations by a group of twenty doctors following a closed-door discussion based on the scientific evidence available for India and Bangladesh regarding the prevention of respiratory tract infections in Hajj pilgrims.

Thallium-201 scintigraphy in the evaluation of graft dysfunction in lung transplantation. Newark Beth Israel Medical Center Lung Transplant Group.

The object of this study was to evaluate graft dysfunction utilizing thallium-201 scintigraphy in patients who had undergone lung transplantation. We studied 11 patients who had undergone single-lung transplantation and had 44 evaluations for suspected graft dysfunction. All evaluations included a lung thallium-201 scan and chest radiography. In addition, 42 transbronchial biopsies, 19 gallium-67 scans and 28 pulmonary function tests were obtained. Rejection was defined by histopathology and/or the response to an empirical pulse of methylprednisolone, while cultures of protected specimen brushes and blood with a positive chest radiograph were used to define infection. The sensitivity of thallium scintigraphy for diagnosing rejection and/or infection (94%) was higher than that for transbronchial biopsy (86%), gallium scintigraphy (47%), chest radiography (67%), or spirometry testing (30%). Specificity was 100% for thallium scintigraphy and transbronchial biopsy, as compared to chest radiography and spirometry, which were 75 and 80% respectively. This study indicated that thallium-201 scintigraphy is useful for screening lung transplant recipients for episodes of acute rejection and/or infection. A positive scan is confirmation of graft parenchymal dysfunction and may then be followed by empirical treatment or bronchoscopy with transbronchial biopsy and culture to differentiate rejection and infection.