Tunable Visible Emission of Ag-Doped CdZnS Alloy Quantum Dots

Highly luminescent Ag-ion-doped Cd1−xZnxS (0 ≤ x ≤ 1) alloy nanocrystals were successfully synthesized by a novel wet chemical precipitation method. Influence of dopant concentration and the Zn/Cd stoichiometric variations in doped alloy nanocrystals have been investigated. The samples were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) to investigate the size and structure of the as prepared nanocrystals. A shift in LO phonon modes from micro-Raman investigations and the elemental analysis from the energy dispersive X-ray analysis (EDAX) confirms the stoichiometry of the final product. The average crystallite size was found increasing from 1.0 to 1.4 nm with gradual increase in Ag doping. It was observed that photoluminescence (PL) intensity corresponding to Ag impurity (570 nm), relative to the other two bands 480 and 520 nm that originates due to native defects, enhanced and showed slight red shift with increasing silver doping. In addition, decrease in the band gap energy of the doped nanocrystals indicates that the introduction of dopant ion in the host material influence the particle size of the nanocrystals. The composition dependent bandgap engineering in CdZnS:Ag was achieved to attain the deliberate color tunability and demonstrated successfully, which are potentially important for white light generation

Extracellular Protease and DNase Activities in Clinical and Environmental Isolates of Cryptococcus neoformans Species Complex from Central India

Enzymes are important not only for the growth and multiplication of the microorganism but also in the infection, penetration of the host tissue and encountering host defense mechanisms. This study aims to investigate extracellular protease and DNase activity in clinical (20) and 120 environmental isolates of C. neoformans species complex collected from different localities of central India.  DNase test agar containing toluidine blue and Yeast Carbon Base (YCB) agar medium supplemented with 0.1% BSA + 0.01% polypeptone was employed for the screening of DNase and protease production respectively. DNase and protease production was detected by the appearance of clear zones around the colonies. On the basis of enzymatic activity and their Pz values, high protease production (Pz≤0.6) was observed by 14 (11.6 %) environmental and 4 (11.6 %) clinical strains on 5th day, whereas 35 (29.16 %) environmental and 8 (40 %) clinical strains were screened on 8th day of incubation. Similarly 13 (10.83%) environmental and 3 (15 %) clinical strains on the 5th day, however 32 (26.66%) environmental and 8 (40 %) clinical strains on the 8th day of incubation were found to be high DNase producing strains with low Pz value (Pz≤0.6). In the case of protease activity, no significant difference was observed whereas a significant difference has shown by clinical C. neoformans and C. gattii strains on the 5th day of DNase production (p < .001). Extracellular enzymes play a vital role in the pathogenicity and virulence of C. neoformans species complex, therefore, enzymes are considered as worthy targets for developing therapeutics. Keywords: Cryptococcus neoformans species complex, Extracellular enzymes, DNase, protease, virulence, Pz valu

Terphenyl derivatives as “turn on” fluorescent sensors for mercury

New terphenyl-based reversible receptors 1−4 with pyrene and quinoline as the fluorophores have been designed, synthesized, and examined for their cation recognition abilities toward various cations (Sm3+, Nd3+, Pb2+, Hg2+, Ba2+, Cd2+, Ag+, Zn2+, Cu2+, Ni2+, Co2+, Fe2+, Fe3+, K+, Mg2+, Na+, and Li+) by UV−vis, fluorescence, and NMR spectroscopy. The prepared receptors showed the highly selective and sensitive “Off−On” fluorescence signaling behavior for Hg2+ ions in THF and mixed aqueous media (THF:H2O, 9.5:0.5)

Original Article Section: Ophthalmology Pattern of Ocular Morbidity among Children Referred Through a National Screening Program in a Tertiary Hospital in Northern India

ABSTRACT Background: The Rashtriya Bal Swasthya Karyakram (India) is directed towards achieving universal health coverage among children by early detection of diseases. Under the scheme, children are screened at the level of schools and community and are thereafter referred to tertiary centre. The purpose of study was to identify common causes of ocular morbidity in children screened and referred through this national screening program. Methods: Retrospective analysis of records of all children who presented to our centre with ocular problems over a period of one year (2015) was undertaken. Clinical diagnosis was recorded on a seven point scale based on major anatomical involvement. An analysis of causes of visual impairment was undertaken with a special emphasis on avoidable and treatable causes. Results: A total of 851 subjects presented with ocular problems (mean age 9.5±4.9 years); of them 819 were classified into seven major clinical groups and subgroups. Most common clinical group was that of strabismus (59.9%), followed by refractive errors (16.9%), lids related disorders (6.2%), orbit and adnexal developmental defects (4.6%), lenticular (3.3%), corneal and conjunctival (3.2%) and retinal disorders (2.1%). A total of 49.7% cases had avoidable or treatable causes of visual impairment. Conclusion: A national program with capacity to screen and ensure appropriate referral facilities resulted in intervention in many cases with avoidable and treatable causes of visual impairment. A varied pattern of ocular morbidity was found among the referred cases; our study could provide a platform for a target oriented approach towards planning and implementation of such screening programs

Clinical investigation of periodontal ligament distraction osteogenesis for rapid orthodontic canine retraction

To investigate rapid canine distalisation by periodontal ligament distraction and to determine the effects of periodontal ligament distraction on the canine root and pulpal vitality