Optical properties of Yb3+ doped ZnO/MgO nanocomposites

[EN] Yb3þ doped ZnO/MgO nanocomposite were prepared by combustion synthesis method. The samples were further heated to 1000 °C to improve their crystallinity and photoluminescent efficiency. The concentrations of Yb3þ and Mg2þ were varied between 1–2% and 5–70% respectively in prepared samples. The nano-powders were characterized by Scanning Electron Microscopy and X-ray Diffraction for morphology and structural determination. XRD studies have revealed the wurtzite structure for MgxZn1"xO for Mg concentrations below 30%. Higher concentrations of Mg results in Yb3þ doped ZnO/ MgO nanocomposite containing three phases; the wurzite hexagonal phase typical of ZnO, the cubic phase of MgO and a small amount of cubic Yb2O3 phase. As expected, the amount of cubic phase in nanopowders increased with the increase of Mg concentration in ZnO. The crystallite size of ZnO/MgO composites decreased from 55 nm to 30 nm with increase of Mg content. SEM images of Yb3þ doped ZnO/MgO nanocomposite with higher Mg content (450%) showed clearly distinct hexagonal and cubical shaped nano-particles. Photoluminescent emission showed a broad band in the range (435 nm to 700 nm). Pure ZnO nano-phosphor showed an emission peak around 545 nm, which is blue shifted with Mg content. The photoluminescence intensity increased with increase of Mg content in ZnO and it became maximum with 30% Mg concentration. Time resolved decay curves of photoluminescence indicated decay time in microsecond time scaleThis work was supported by Ministerio de Economia y Competitividad (ENE2013-46624-C4-4-R), Generalitat Valenciana (PROMETEUS-II/2014/044) and the European Commission through NanoCIS project (FP7-PEOPLE-2010-IRSES ref. 269279).Marí, B.; Singh, KC.; Verma, N.; Jindal, J. (2016). Optical properties of Yb3+ doped ZnO/MgO nanocomposites. Ceramics International. 42(11):13018-13023. https://doi.org/10.1016/j.ceramint.2016.05.079S1301813023421

Low-pressure Chemical Vapour Deposition of Silicon Nanoparticles:Synthesis and Characterisation

emiconductor nanostructures such as quantum wells, quantum wires or quantum dots exhibit superior properties in comparison to their bulk forms. Quantum dots are described aszero-dimensional electron gas system, as carriers are confined in all the three directions. Densityof states is discrete function of energy. Allowed energy spectrum is discrete like in an atom.Energy band gap is broadened due to carriers confinement. Semiconductor quantum dots exhibittypical coulomb blockade characteristic which is exploited for development of new generationof nanoelectronic devices namely single-electron transistor, memories, etc, whose operationdepends on quantum mechanical tunneling of carriers through energy barriers. Thesesemiconductor nanostructures emit light in visible range upon excitation by optical means. Inrecent years,  research  has been focused on different nano-scale materials; metals (Au, Ag, Fe,Mn, Ni), metal oxides (SnO2, ZnO2), compound semiconductors (GaAs, GaAlAs, CdSe, CdS,GaN), and elemental semiconductors (silicon and germanium). As silicon is the most favouredmaterial in the established integrated circuits manufacturing technology, research is being donefor controlled synthesis and characterisation of Si nanoparticles. The Si nanoparticles havebeen synthesised on oxide and nitride layers over  Si substrate by IC technology compatiblelow-pressure chemical vapour deposition technique. Atomic force microscopy (AFM)characterisation has been extensively carried out on the samples. It is shown that the tip radiusand shape of tip lead to less accurate estimate of the actual size. The AFM images have been evaluated based on the real surface topography and shape of the tip. Photolumine scence (PL) studies have been performed to characterise the samples. The PL measurements showed visiblelight emission from synthesised silicon nanoparticles.Defence Science Journal, 2008, 58(4), pp.550-558, DOI:http://dx.doi.org/10.14429/dsj.58.167

Heterosis in single cross inter and intra-specific hybrids of Desi cotton (Gossipium arboreum and G. herbaceaum) for their seed cotton yield, fibre quality and seed oil content

The present investigation was carried out to assess the expression of per se performance and heterotic effect for fibre quality and seed oil content besides seed cotton yield, studied involving ten desi cotton (Gossipium arboreum and G. herbaceaum) genotypes and their 45 cross combinations in half diallel analysis. F-1 hybrids GBhv-282 x G 27 (67.36%), GBhv- 287 x 824 (58.14%), GBhv- 282 x GAM- 173 (35.00%), GBhv- 286 x G 27 (20.50%), and GBhv- 283 x 824 (18.75%) recorded highest per se performance and significant positive standard heterosis while the maximum heterobeltiosis for seed cotton yield per plant was exhibited by the hybrid GBhv- 287 x 824(155.60 %) followed by GBhv- 282 x G 27 (151.29%) and GBhv- 282 x GAM- 173 (130.30%). Similar trend of heterosis for numbers of boll per plant were observed in above hybrids. For fibre quality traits none of the cross showed consistent high performance for all the characters. Cross GBhv- 283 x 824 was exhibited high standard heterosis for 2.5 % span length, fibre strength, fibre elongation percentage as well as for short fibre index (SFI) while cross GBhv- 286 x 824 were promising for 2.5 per cent span length, fibre strength and fibre fineness. In case of oil content intraarboreum crosses resulted as better crosses and among them cross combination 824 x GAM- 173 was best. Desi cotton hybrids are having lower fibre quality and yield. So, improvement for yield and fibre quality of diploid native varieties through heterosis breeding provided better hybrids for rainfed farming

Study the antimicrobial agents sensitivity of methicillin resistant Staphylococcus aureus isolated from patients admitted in RIMS, Ranchi

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired infections that are becoming increasingly difficult to combat because of emerging resistance to all current antibiotic classes. For this, study of MRSA isolated from admitted patients were carried out. These strains were separately tested for their sensitivity to different antibiotics to know which group of antibiotics are most effective particularly for cases of RIMS, Ranchi. Material & Methods: The present study was carried out in the Department of Microbiology, Rajendra Institute of Medical Sciences (RIMS), Ranchi clinical isolates of MRSA strains were obtained from admitted patients of RIMS, Ranchi. The sources of isolate included pus from infected surgical wounds, infected burn wounds, conjunctival swab, aural swab, throat swab, vaginal swab, urine etc for microbiological analysis and antimicrobial sensitivity of MRSA. Disc diffusion method was employed. Results: All the 264 cases of staphylococcal species isolated from different clinical specimens were subjected to coagulase test. It was observed that out of 264 strains of staphylococci isolated from different sites 165 strains (62.5%) were coagulase positive and 99 strains (37.5%) were coagulase negative by tube method. It was observed that out of 165 strains of staph. aureus isolated from different clinical samples 64 strains of staph. aureus were resistant to methicillin (38.78%). Maximum isolation of MRSA were from pus 38 (51.35%), followed by throat swab 19 (36.36%), aural swab (14.28%) and conjunctival swab (44.44%). It was observed that out of 165 strains of s. aureus isolated only 64 strains were resistant to methicillin. All strains of MRSA were 100% sensitive to Vancomycin & linezolid. Similarly 92.3% were sensitive to netilmicin, 89.7% to clindamycin, 82.1% to ciprofloxacin, 74.4% to cephotaxime, 69.2% to azithromycin, 56.4% to roxithromycin & clarithromycin, 17.9% to piperacillin/tazobactam. The most effective antibiotic against MRSA was vancomycin, linezolid, netilmicin & clindamycin. Conclusion: After comparing the effectiveness of antibiotics against MRSA infection it can be concluded that piperacillin/tazobactam, clarithromycin, roxithromycin azithromycin, cefotaxime & ciprofloxacin are of little value in treating the MRSA infection. They should not be used indiscriminately and in a haphazard manner otherwise increment in emergence of resistant strains may not be checked

Evaluation of insecticides against cotton mealybug, Phenacoccus solenopsis Tinsley and their safety to important predators

254-262Cotton plays an important role in the world economy by supplying raw materials to different manufacturing units. Of late, it is being seriously attacked by the cotton mealybug, Phenacoccus solenopsis Tinsley. The biological control involving coccinellid beetles and chrysopids as predators could lead to ecologically sustainable mealybug control. Here, in the context of conservation of natural enemies, we exploredthe efficacy of insecticides on the cotton mealybug and also safety to other predators. Six insecticides viz; chlorpyrifos 20 EC (0.05%), endosulfan 35 EC (0.07%), monocrotophos 36 SL (0.04%), malathion 50 EC (0.12%), dichlorvos 76 EC (0.15%), and alphamethrin 10 EC (0.01%) were tested for their residual toxicity against the mealybug, P. solenopsis and its coccinellid predators. Studies revealed that, both chlorpyrifos and malathion showed highest toxicity in terms of mean mortality (100%) to female mealybugs at 24 h of exposure as against lowest in endosulfan (35%). Interestingly, chlorpyrifos and dichlorvos, which proved toxic to mealybug were less toxic to the grubs of Cryptolaemus montrouzieri, registering only 21.66 per cent and 34.16 per cent mortality, respectively. These insecticides when offered to the adults along with honey differed in toxicity as stomach poison at 24 hrs of exposure. Endosulfan registered mortality to the tune of 60 and 70% against Coccinella septempunctata and Cheilomenes sexmaculata, respectively. However, stomach toxicity pertaining to the insecticide-sprayed mealybugs as prey offered to all the three species of predators indicated that the insecticides, chlorpyrifos and endosulfan were lesser toxic to these wherein mean mortality ranged from 38.09 to 56.66 and 50 to 65.71%, respectively. Dichlorvos was the most toxic, registering 100% mortality for all 3 predators viz. Nephus regularis, Scymnus coccivora and Hyperaspis maindroni. The release of C. montrouzieri coupled with chlorpyrifos is likely to be a better option for the management of mealybugs infesting several agri-horticultural crops

Evaluation of insecticides against cotton mealybug, Phenacoccus solenopsis Tinsley and their safety to important predators

Cotton plays an important role in the world economy by supplying raw materials to different manufacturing units. Of late, it is being seriously attacked by the cotton mealybug, Phenacoccus solenopsis Tinsley. The biological control involving coccinellid beetles and chrysopids as predators could lead to ecologically sustainable mealybug control. Here, in the context of conservation of natural enemies, we exploredthe efficacy of insecticides on the cotton mealybug and also safety to other predators. Six insecticides viz; chlorpyrifos 20 EC (0.05%), endosulfan 35 EC (0.07%), monocrotophos 36 SL (0.04%), malathion 50 EC (0.12%), dichlorvos 76 EC (0.15%), and alphamethrin 10 EC (0.01%) were tested for their residual toxicity against the mealybug, P. solenopsis and its coccinellid predators. Studies revealed that, both chlorpyrifos and malathion showed highest toxicity in terms of mean mortality (100%) to female mealybugs at 24 h of exposure as against lowest in endosulfan (35%). Interestingly, chlorpyrifos and dichlorvos, which proved toxic to mealybug were less toxic to the grubs of Cryptolaemus montrouzieri, registering only 21.66 per cent and 34.16 per cent mortality, respectively. These insecticides when offered to the adults along with honey differed in toxicity as stomach poison at 24 hrs of exposure. Endosulfan registered mortality to the tune of 60 and 70% against Coccinella septempunctata and Cheilomenes sexmaculata, respectively. However, stomach toxicity pertaining to the insecticide-sprayed mealybugs as prey offered to all the three species of predators indicated that the insecticides, chlorpyrifos and endosulfan were lesser toxic to these wherein mean mortality ranged from 38.09 to 56.66 and 50 to 65.71%, respectively. Dichlorvos was the most toxic, registering 100% mortality for all 3 predators viz. Nephus regularis, Scymnus coccivora and Hyperaspis maindroni. The release of C. montrouzieri coupled with chlorpyrifos is likely to be a better option for the management of mealybugs infesting several agri-horticultural crops

Improved crop productivity and rural livelihoods through balanced nutrition in the rainfed semi-arid tropics

Diagnostic soil analysis in targeted clusters of eight districts in Andhra Pradesh revealed critical deficiencies of sulphur (61 to 98%), boron (23 to 98%) and zinc (45 to 85%) in addition to that of soil carbon (25 to 97%), and phosphorus (14 to 84%) which are apparently holding back the productivity potential. The soil test based application of sulphur, boron and zinc together increased productivity by 8 to 102% in cotton, groundnut, castor, sorghum, greengram, cowpea, chickpea and maize. Economic assessment reveal that per rupee invested as additional cost (` 1,400/- to ` 2,150/-) gave ` 1.6 to 28.5 in return. Residual benefits of balanced nutrition were observed during 4 succeeding seasons. Soil health improved in balanced nutrition plots, inspite of higher yields and nutrient removal. The results showed that balanced nutrition is the way forward to increase crop productivity through resilience building of production systems and improve farm based livelihoods in the SAT regions

Association of History of Injection Drug Use with External Cause-Related Mortality Among Persons Linked to HIV Care in an Urban Clinic, 2001–2015

High mortality rates among persons with HIV with a history of injection drug use (PWID) are thought to be driven in part by higher rates of external cause-related mortality. We followed 4796 persons aged 18–70 engaged in continuity HIV care from 2001 to 2015 until death or administrative censoring. We compared cause-specific (csHR) and subdistribution hazards (sdHR) of death due to external causes among PWID and persons who acquired their HIV infection through other routes (non-IDU). We standardized estimates on age, sex, race, and HIV-related health status. The standardized csHR for external cause-related death was 3.57 (95% CI 2.39, 5.33), and the sdHR was 3.14 (95% CI 2.16, 4.55). The majority of external cause-related deaths were overdose-related and standardized sdHR was 4.02 (95% CI 2.40, 6.72). Absolute rate of suicide was low but the csHR for PWID compared to non-IDU was most elevated for suicide (6.50, 95% CI 1.51, 28.03). HIV-infected PWID are at a disproportionately increased risk of death due to external causes, particularly overdose and suicide