Antioxidant and Photocatalytic Activity of Aqueous Leaf Extract Mediated Green Synthesis of Silver Nanoparticles Using Passiflora edulis f. flavicarpa.

The purpose of this study is to minimize the negative impacts of synthetic procedures and to develop environmentally benign procedures for the synthesis of metallic nanoparticles. In the present study, Passiflora edulis f. flavicarpa (P. edulis) aqueous leaf extract mediated green synthesis of silver nanoparticles are described. The synthesized silver nanoparticles were characterized by UV-Vis Spectroscopy, Fluorescence Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) Transmission Electron Microscopy (TEM) and Cyclic Voltammetry (CV). The silver nanoparticles (AgNPs) showed antibacterial activities against both gram positive (staphylococcus) and gram negative (Escherichia coli) bacteria. The efficacy of the synthesized silver nanoparticles (AgNPs) was demonstrated as catalyst in the photocatalytic degradation of Methyl Orange (MO) and Methylene Blue (MB) dyes which were measured spectrophotometrically. The study revealed that biosynthesized silver nanoparticles using Passiflora. edulis f. flavicarpa, plant extract was found to be very effective as antioxidant agent.

Up-Scalable Synthesis of Size-Controlled White-Green Emitting Behavior of Core/Shell (CdSe/ZnS) Quantum Dots for LED Applications.

Research on CdSe/ZnS core-shell quantum dots (QDs) was synthesized by a chemical route using bio-conjugated organic amino acid (L-Cysteine). The structural, morphological, and optical properties of the nanocrystal powder samples were analyzed using various characterization techniques. The diameter of the resulting QDs was about 3 nm with uniform size distribution. The optical properties QDs exhibited an absorption and emission peak at 515 and 525 nm respectively, at room temperature. The QDs through emission in the spectral range at 516-535 nm is special for their application in green LEDs and white-light generation. The high optical properties performance of the QDs nanocomposites gained indicates that the materials are promising for (LED) applications.

Significance of microbial genome in environmental remediation.

Environmental pollutants seriously threaten the ecosystem and health of various life forms, particularly with the rapid industrialization and emerging population. Conventionally physical and chemical strategies are being opted for the removal of these pollutants. Bioremediation, through several advancements, has been a boon to combat the existing threat faced today. Microbes with enzymes degrade various pollutants and utilize them as a carbon and energy source. With the existing demand and through several research explorations, Genetically Engineered Microorganisms (GEMs) have paved to be a successful approach to abate pollution through bioremediation. The genome of the microbe determines its biodegradative nature. Thus, methods including pure culture techniques and metagenomics are used for analyzing the genome of microbes, which provides information about catabolic genes. The information obtained along with the aid of biotechnology helps to construct GEMs that are cost-effective and safer thereby exhibiting higher degradation of pollutants. The present review focuses on the role of microbes in the degradation of environmental pollutants, role of evolution in habitat and adaptation of microbes, microbial degenerative genes, their pathways, and the efficacy of recombinant DNA (rDNA) technology for creating GEMs for bioremediation. The present review also provides a gist of existing GEMs for bioremediation and their limitations, thereby providing a future scope of implementation of these GEMs for a sustainable environment.

Associations Between Suicidal Behaviour, Attitudes Towards Suicide, and Psychological Distress Among Students in a University in East Malaysia.

BACKGROUND: Suicidal behaviour can be influenced by attitudes towards suicide and psychological distress. This study aimed to investigate the associations between psychological distress, attitudes towards suicide, and suicidal behaviour and to determine the prevalence of suicidal behaviour among students of a public university in East Malaysia. METHODS: A total of 521 students from a public university in East Malaysia were asked to complete the Malay versions of the Suicidal Behaviour Questionnaire-Revised (SBQ-R), the Attitudes Towards Suicide Scale, and the Depression Anxiety Stress Scale. RESULTS: 197 women and 290 men (mean age, 19.13 years) completed the questionnaires, giving a response rate of 93.4%. The prevalence of high-risk suicidal behaviour (SBQ-R score ≥7) was 23.8%. Suicidal behaviour was positively associated with psychological distress and favourable attitudes towards suicide, and negatively associated with unfavourable attitudes towards suicide. Predictors for suicidal behaviour were psychological distress and favourable attitudes towards suicide ('the ability to understand and accept suicide'). CONCLUSION: The prevalence of suicidal behaviour is high among students in a public university in East Malaysia. Services and education for mental health awareness and screening for early detection and intervention of psychological distress should be provided to university students. Implementation of suicide awareness policies and suicide prevention training is crucial.

Kinetic modeling of the SWNT growth by CO disproportionation on CoMo catalysts.

A kinetic model has been developed to describe the growth of single-walled carbon nanotubes (SWNT) in the CoMoCAT method, which is based on the disproportionation of CO on supported CoMo catalysts. The model attempts to capture mathematically the different stages involved in this method: (i) catalyst activation or in-situ creation of active sites, i.e., reduced Co clusters by transformation of CoMoOx precursor species, or oxidized sites; (ii) CO decomposition over active sites, which increases the surface fugacity of carbon until reaching a certain threshold; (iii) nucleation of ordered forms of carbon; (iv) C diffusion (both across the surface and into the metal particle); (v) SWNT growth; (vi) termination, by either deactivation of the catalyst active sites or by increase in the carbon concentration at the metal/SWNT interface, approaching that of the metal/gas interface and eliminating the driving force for diffusion. Previous investigations have only explained the growth termination by the former. Here, we emphasize the possible contribution of the later and propose a novel "hindrance factor" to quantify the effect of nanotube interaction with its surroundings on the growth termination. To test the kinetic model and obtain typical values of the physical parameters, experiments have been conducted on a CoMo/SiO2 catalyst in a laboratory flow reactor, in which the rate of carbon deposition was continuously evaluated by the direct measurement of the CO2 evolution as a function of time. The experimental data are fitted very well with model.

Antibacterial, magnetic, optical and humidity sensor studies of ß-CoMoO4 - Co3O4 nanocomposites and its synthesis and characterization.

Cobalt Molybdate (ß-CoMoO4) and Cobalt Oxide (Co3O4) nanocomposite was prepared via co-precipitation and solid-state methods. Various techniques like powder XRD, FESEM, HRTEM, FTIR, VSM, UV-Vis and PL spectroscopy were used to investigate the structure and morphology of as prepared samples. Powder X-ray diffraction (XRD) reveals monoclinic and cubic structure for ß-CoMoO4 and Co3O4 respectively. The surface morphology was observed using field emission electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM), which shows the formation of nanocomposites at nanoscale range, the presence of elements were determined by energy dispersive x-ray spectroscopy (EDX). FTIR analysis confirms the formation and bonding nature of the samples. The anti-ferromagnetic behavior of CMCO64 composite was determined by vibrating sample magnetometer (VSM). The bandgap values were calculated by extrapolating the straight line on the energy axis (hν), and the values of ß-CoMoO4, CO3O4 and ß-CoMoO4 - CO3O4 composites were determined to be 2.20, 2.09 eV and 1.54-2.44 eV respectively. The weak blue emission peak observed at 489 nm is corresponds to crystal defects only observed in CMCO01 and CMCO64 composite, for CMCO10 the peak shifted to green region. Antibacterial studies illustrate good result for the CMCO64 composite against both Gram-negative and Gram-positive bacteria. The sensor studies were measured at different humidity environment (RH5% to RH98%). It was found that the increase in relative humidity leads to increase in the sensitivity factor of the samples. Among the samples CMCO64 composite possess highest sensitivity factor of (Sf = 4851) with response time of 60 s and recovery time of 230 s respectively.

Extracorporeal shock wave lithotripsy as first line treatment for urinary tract stones in children: outcome of 500 cases.

PURPOSE: The continued evolution of stone treatment modalities, such as endourologic procedures, open surgery and shock wave lithotripsy, makes the assessment of continuous outcomes are essential. Pediatric urolithiasis are an important health problem allover the world, especially in Middle East region. We evaluate the safety, efficacy and factors affecting success rate and clearance of stones in children treated with shock wave lithotripsy. PATIENT AND METHODS: Between 2005 and 2010, a total of 500 children with stones in the upper urinary tract at different locations were treated by Extracorporeal shock wave lithotripsy (ESWL) in our department, Sohag University, Egypt. We have used the Siemn's Lithostar Modularis machine, Germany. A total of 371 boys and 129 girls with the average age of 8.63 ± 5 years, and a range from 9 months to 17 years were included in this study. Diagnosis of their urinary calculi was established either by the use of abdominal ultrasound, plain X-ray, intravenous urography, or CT scan. The stones were located in the kidney in 450 (90%) patients; 298 (66%) pelvic, 26 (5.7%) upper calices, 57 (12.6%) mid calices, and lower calices in 69 (15.3%) patients. The average of their stone sizes was 12.5 ± 7.2 mm. The other 50 children their stone were located in the proximal ureteral stones in 35 patients (70%); middle third in 5 (10%) patients and in the distal ureter in 10 (20%) patients. The average ureteral stone size was 7.5 ± 3.2 mm. All children were treated under general anesthesia with adequate lung and testes shielding using air foam. We treated the distal ureteral stones of young children in the supine position through greater sciatic foramen and lesser sciatic foramen as the path of shockwave instead of prone position, which is not a comfortable or natural position and could adversely affect cardiopulmonary function especially under general anesthesia. Localization was mainly done by ultrasound, and X-ray was only used to localize ureteral calculi. For follow-up, we have used abdominal ultrasound, plain X-ray, and CT scan if needed to confirm stone disintegration and clearance. RESULTS: The overall success rate for renal and ureteral calculi was 83.4 and 58.46%, respectively. The re-treatment rate was 4% in renal group and 28% for the ureteral group. No serious complications were recorded in our patients. Minor complications occurred in 15% of our patients; renal colic was reported in 10% of our treated patients, and repeated vomiting was reported in 5% that respond to antiemetics. In the renal group; children with history of pervious urologic surgical procedures had low success rate of stone clearance after ESWL. In the ureteral group stone burden, stone location, had a significant impact on stone clearance outcome. CONCLUSION: This study showed that SWL in pediatric age group for both renal and ureteral stone is cost effective, safe with an acceptable re-treatment rate; however children with large stone burden or previous urologic surgery have low success rate.