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We report the detailed structural and luminescence properties of Si-embedded single layer Ge nanoislands grown via Stranski-Krastanov mechanism using molecular beam epitaxy. The luminescence energy peak positions correlated with structural properties have been studied as a function of the growth temperature and post-growth annealing. The photoluminescence peak for the annealed sample (500 °C grown) is blue shifted with increasing anneal temperature compared to the as grown sample due to intermixing of Si/Ge. Electroluminescence from the single layer Ge islands in the wavelength range 1.53 to 1.67 μm has been demonstrated using a metal-insulator-semiconductor structure, making it attractive for quantum dot light emitting devices. [ABSTRACT FROM AUTHOR]

Quantum confined Ge nanocrystals embedded in high bandgap and high-k Al2O3 dielectric matrix have been synthesized to demonstrate dual functional devices using Si-compatible fabrication technology. Transmission electron microscopy has shown the formation of Ge nanocrystals of varying diameter from 2.5 to 7.5 nm, much lower than the excitonic Bohr radius of Ge. A broad visible electroluminescence band at room temperature has been observed, which is attributed to the recombination of injected electrons and holes in Ge nanocrystals. An anti-clockwise hysteresis in the capacitance-voltage measurement of these devices indicates the charge storage in nanocrystals, useful for floating gate memory devices. [ABSTRACT FROM AUTHOR]

Ge nanocrystals embedded in HfO2 matrices were prepared by rf magnetron sputtering technique. Transmission electron micrographs reveal the formation of spherical shape Ge nanocrystals of 4-6 nm diameters for 800 °C and 6-9 nm for 900 °C annealed samples. X-ray photoelectron spectroscopy confirms the formation of surface oxidized Ge nanocrystals. Embedded Ge nanocrystals show strong photoluminescence peaks in visible and ultraviolet region even at room temperature. Spectral analysis suggests that emission in 1.58 and 3.18 eV bands originate from TΣ(TΠ)→S0, and TΠ′→S0 optical transitions in GeO color centers, respectively, and those in the range 2.0-3.0 eV are related to Ge/O defects at the interface of the oxidized nanocrystals. Temperature dependent photoluminescence study has revealed additional fine structures with lowering of temperature, the origin of which is attributed to the strong coupling of electronic excitations with local vibration of germanium oxides at the surface. [ABSTRACT FROM AUTHOR]

Self-assembled Ge islands have been grown using a Stranski–Krastanov growth mechanism on Si (001) substrates by solid source molecular beam epitaxy. We performed time varying annealing experiments at a representative temperature of 650 °C to study the shape and size evolution of islands for a relatively high Ge coverage. Islands are found to coarsen due to heat treatment via structural and compositional changes through continuous strain relaxation. Different island morphologies, namely, “pyramids,” “transitional domes,” and “domes” are found during the annealing sequence. The dominant coarsening mechanisms for the temporal evolution of islands of as-grown and annealed samples are explained by the comprehensive analysis of Rutherford back scattering, Raman spectroscopy, high-resolution x-ray diffraction, and atomic force microscopy. A correlation of the morphological evolution with the composition and strain relaxation of grown islands is presented. [ABSTRACT FROM AUTHOR]

Background: Suicide is a leading cause of death worldwide. This is the first study in Bangladesh to find out the psychiatric morbidity profile and suicidal behavior. The study was aimed to delineate the types of suicidal behavior and the psychiatric morbidity profile, and sociodemographic status of patients. Methods: A descriptive cross-sectional study was done in Depatrment of Psychiatry, Cumilla Medical College, Cumilla from October 2015 to March 2017. A total 120 patient aged 9 to 40 years who fulfilled the enrolment criteria included in the study. The Composite International Diagnostic Interview (CIDI) module was used to assess the suicidal behavior. DSM-5 was used to diagnose the psychiatric disorders. Semi structural questionnaire were used for collecting information about the risk factors for psychiatric morbidity and sociodemographic information. Result: Of 120 suicidal behavior patients' psychiatric disorders was 65%. Among suicidal behavior patients neurotic disorders was 19%, psychotic disorders was 15%, personality disorders was 39% and others disorder was 27%. Among 78 psychiatric patients borderline personality disorder was 25.64%, adjustment disorders were 15.38%, mood disorders were 11.53%, psychotic disorder was 7.69%, multiple personality disorder and oppositional defiant disorder were 6.42%, hystrionic personality disorder and substance use disorder were 3.84%, antisocial personality disorder, conduct disorder and anxiety disorder were 2.57%, and composite disorder was 11.53%. Among suicidal behavior in psychiatric patients suicidal ideation was 54, suicidal plan was 13, suicidal attempt was 45, ideators only proceeded to plan was 17, ideation to attempt was 59. Among suicidal behavior in total 120 participants suicidal ideation was 84, suicidal plan was 19, suicidal attempt was 56, ideators only proceeded to plan was 26, ideation to attempt was 76, planned attempt was 14 and impulsive attempt was 62. Most of the suicidal behavior participants were female (77.5%) and age group of <24 years (60%). Conclusions: Psychiatric disorders are important risk factors for the onset and persistence of suicidal behaviour, with this risk being the greatest in childhood, and early adult. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are endogenous, non-coding RNAs, which have evoked a great deal of interest due to their importance in many aspects of homeostasis and diseases. MicroRNAs are stable and are essential components of gene regulatory networks. They play a crucial role in healthy individuals and their dysregulations have also been implicated in a wide range of diseases, including diabetes, cardiovascular disease, kidney disease, and cancer. This review summarized the current understanding of interactions between miRNAs and different diseases and their role in disease diagnosis and therapy. [ABSTRACT FROM AUTHOR]

Rhododendron wattii Cowan is a rare and endangered plant found in northeast India. In an effort to boost specimen numbers, experiments of in vitro seed germination, shoot induction on different media supplemented with the cytokinin isopentenyladenine (2iP), and root induction with auxins α-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA) in woody plant medium (WPM) were carried out. A maximum mean shoot number of 7.72 per explant were obtained from nodal explants cultured on WPM and 39.36 μM 2iP with a maximum mean shoot length of 2.30 cm per explant. Among the auxins investigated for root induction, IBA at 2.45 μM was found to produce the most and the longest roots, when compared to other treatments. However, WPM supplemented with 0.2% (w/v) activated charcoal also showed 100% root formation with shoots having broader leaves compared to auxin treatments. About 60% of in vitro rooted plantlets transferred from lab to greenhouse conditions survived. Sixty acclimatized plants were reintroduced in the vicinity of their natural habitat at Naga Heritage Village, Kisama, Nagaland, in May 2016 for ex situ conservation. Survival of the reintroduced plants was confirmed during the field visit conducted in November 2016. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of methylene blue was studied using ZnO nanopowders prepared through a green synthesis process. An aqueous solution of methylene blue was investigated in an open vessel equipped with sun light using ZnO nanopowders, as catalyst, with a concentration of 7.815 × 10-6 M. ZnO nanomaterials, prepared through a green synthesis method, was characterized with XRD, FTIR, SEM, EDX and BET measurements. The photodegradation of methylene blue in terms of concentration change with respect to different time intervals was studied with the UV-vis spectroscopy. The mechanism for this photocatalytic degradation process has also been presumed. [ABSTRACT FROM AUTHOR]

Studies of the impact of mental disorders on educational attainment are rare. Mental disorders, those beginning in childhood or adolescence may increase the risk of early drop out from education. The latter has been shown to have adverse life-course consequences on individuals such as greater demand on social welfare entitlements. A descriptive cross sectional study was carried out at the department of Psychiatry, Comilla Medical College, Comilla, Bangladesh. All cases were selected from patients attending at Comilla Medical College Hospital and Private Mental Health Facilities in Comilla City from March 2015 to February 2016. We found out the psychiatric disorders and socio-demographic status of patients with educational drop out over the early life course. A total of 50 dropout patients aged 10 to 30 years who fullfiled the enrolment criteria included in the study. Sociodemographic questionnaires, diagnostic information (DSM-5 and ICD-10) as well as an account of a various level of education were used as research instruments. The Frequency tables, summary tables and appropriate graphs were prepared to describe the population characteristics and study finding. The most of the psychiatric morbidity presents in male (62%) and age group of 18-24 years (54%). In this study, anxiety disorders was 8%, behaviour/ impulse control disorders was 8%, mood disorders was 16%, substance use disorders was 24%, schizophrenia spectrum disorders was 12% and composite psychiatric disorders was 32%. Among drop out patient's non- completion of primary education was 14%, non-completion of secondary education was 20%, non- completion of higher secondary education was 24%, not entry to tertiary education was 12% and non-completion of tertiary education was 30%. Among behaviour/impulse control disorders non-completion of primary education was 6%, substance use disorders non-completion of higher secondary education was 10%, mood disorder both non-completion of higher secondary education and non-completion of tertiary education were 6%. Among composite psychiatric disorders non-completion of secondary education, non-completion of higher secondary education and non-completion of tertiary education were 8%, 6% and 12% respectively. Onset of mental disorders and subsequent drop out from education was found in this study. Further multi-centered prospective and population-based studies should be designed to find out the exact situation.