A study to assess the level of knowledge regarding prevention and management of acute respiratory infection among mothers of children 0-5 years in selected hospital in Siliguri

Background: In developing countries like India acute respiratory infection (ARI) contributes in child mortality upto 75% and out of 10, 7 deaths are due to ARI. The knowledge of the mothers towards the disease is a significant determinant of child’s health.Methods: A descriptive cross-sectional study included 100 mothers of children 0-5 years admitted in pediatric ward and postnatal ward in selected hospital Siliguri during the year 2022 in the month of March. Data was collected using structured interview method.Results: 20% of mothers have good knowledge in prevention and 33% had good knowledge in management of ARI.Conclusions: As the leading cause of death among children, knowledge assessment about ARI among the mothers is very important, which helps for better understanding of the intensity of the problem

Role of dopant concentration and surface coating on photophysical properties of CdS : Eu3+ nanocrystals

Here, we report the role of dopant concentration and surface coating of CdS: Eu3+ nanocrystals on the modification of crystal structure and their photoluminescence properties by steady-state and time resolved fluorescence studies. It is found that photoluminescence properties are sensitive to the crystal structure which is controlled by surface coating and dopant concentration. The emission intensity of the peak at 614 nm (5D0 → 7F2) of the Eu3+-ions is found to be sensitive to the doping and surface coating of CdS nanocrystals. It is found that the average decay times 〈τ〉 are 248, 353 and 499 μs for 0.25, 0.5 and 1.0 mol% Eu ions doped into CdS nanocrystals, respectively. From the decay time measurements, it is evident that the energy transfer occurs from CdS nanoparticles to Eu3+ ions and the calculated energy transfer efficiency from CdS nanoparticles to Eu3+ ions is 9.2 and 35% for Eu3+ ions coated and doped CdS nanoparticles, respectively. Our analysis suggests that site symmetry of ions plays a very important role in the modifications of radiative and nonradiative relaxation mechanisms

Role of dopant concentration and surface coating on photophysical properties of CdS: Eu<SUP>3+</SUP> nanocrystals

Here, we report the role of dopant concentration and surface coating of CdS: Eu<SUP>3+</SUP> nanocrystals on the modification of crystal structure and their photoluminescence properties by steady-state and time resolved fluorescence studies. It is found that photoluminescence properties are sensitive to the crystal structure which is controlled by surface coating and dopant concentration. The emission intensity of the peak at 614 nm (<SUP>5</SUP>D<SUB>0</SUB> → <SUP>7</SUP>F<SUB>2</SUB>) of the Eu<SUP>3+</SUP>-ions is found to be sensitive to the doping and surface coating of CdS nanocrystals. It is found that the average decay times 〈&#964; 〉 are 248, 353 and 499 μs for 0.25, 0.5 and 1.0 mol% Eu ions doped into CdS nanocrystals, respectively. From the decay time measurements, it is evident that the energy transfer occurs from CdS nanoparticles to Eu<SUP>3+</SUP> ions and the calculated energy transfer efficiency from CdS nanoparticles to Eu<SUP>3+</SUP> ions is 9.2 and 35% for Eu<SUP>3+</SUP> ions coated and doped CdS nanoparticles, respectively. Our analysis suggests that site symmetry of ions plays a very important role in the modifications of radiative and nonradiative relaxation mechanisms

Influence of nanoenvironment on luminescence of Eu3+ activated SnO2 nanocrystals

The emission intensity of the peak at 612 nm (D-5(0) --> F-7(2)) of the Eu3+ ions activated SnO2 nanocrystals (doped and coated) is found to be sensitive to the nanoenvironment. We have compared the luminescence efficiencies of the nanocrystals of SnO2 doped by Eu2O3 with those of SnO2 coated by Eu2O3 and we found that the intensities are significantly higher in coated nanocrystals. Furthermore, it is clear from luminescence intensity measurements that Eu3+ ions occupy low symmetry sites in the Eu2O3 coated SnO2 nanocrystal. The analysis suggests that the radiative relaxation rate is higher in Eu2O3 coated SnO2 nanocrystals than Eu2O3 doped SnO2 nanocrystals due to the asymmetric environment of Eu3+ ions in coated samples. (C) 2004 Elsevier Ltd. All rights reserve

Study of photophysical properties of capped US nanocrystals

Here, we have examined the role of capping agent on the optical properties of US nanoparticles by steady-state and time-resolved photoluminescence (PL) spectroscopy. The estimated particles sizes are 3.45, 2.5 and 2.39 nm for uncapped, capped with silica (SiO2) and thiosalicylic acid (TSA), respectively. The absorption and emission spectra show a clear blue shift to shorter wavelengths in presence of TSA- and SiO2-capped nanoparticles. It is found that the average decay time are 6.24, 4.54 and 2.84 ns for uncapped, capped with SiO, and TSA nanoparticles, respectively. Our analysis suggests that the hole or the electron is trapped on thiol molecule of TSA or hydroxyl group of SiO2, then radiative recombination of the electron and hole is delayed, resulting in strong quenching of PL efficiency

Optical properties of US nanoparticles and the energy transfer from US nanoparticles to Rhodamine 6G

In the present work, we report the synthesis of colloidal US nanoparticles with different sizes and the band gaps of these samples exhibit a systematic dependence on the size of particles. We also study the photophysical properties of US nanoparticles and the energy transfer from US nanoparticles to Rhodamme 6G dyes by steady state and time resolved photoluminescence spectroscopy. The experimental results show that the relaxation of the excited state of US nanoparticles is composed of three different components. The calculated energy transfer efficiency from US nanoparticles to dye is 43% for 3.0 nm US nanoparticles. (c) 2005 Elsevier B.V. All rights reserved

The role of semiconducting hosts on photoluminescence efficiency of Eu-complex

The energy transfer from the semiconducting hosts, poly (N-vinylcarbazole) (PVK), 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) and a mixture of PVK and PBD blend matrix to Eu-Complex [Eu (TTA)(3)(Phen)] is investigated by steady state and time resolved photoluminescence spectroscopy. The emission intensity of the peak at 612 nm (D-5(0) -> F-7(2)) of Eu-ions and the photoluminescence efficiency are found to be sensitive to the nature of hosts. We found that the luminescence lifetimes of D-5(0) -> F-7(2) transition (612 nm) of Eu-ions are 580, 634 and 427 mu s for Eu-complex (0.11 wt%) doped PVK:PBD, PBD and PVK matrix, respectively. The analysis suggests that the energy transfer from PBD to europium complex is most efficient than PVK and PVK:PBD matrix. (c) 2005 Elsevier B.V. All rights reserved

Luminescence of Ce3+ in Y2SiO5 nanocrystals: Role of crystal structure and crystal size

Here, we report the role of crystal structure and crystal size on the photoluminescence properties of Ce3+ ions in Y2SiO5 nanocrystals. The emission at 430 nm (5d(1) —> 4f(1)) and lifetime of the excited state of Ce3+ ion doped Y2SiO5 nanocrystals are found to be sensitive to the crystal structure, crystal size, and dopant concentration. It is found that the overall lifetime of 0.5 mol % Ce doped Y2SiO5 nanocrystals are 8.78 and 3.45 ns for 1000 and 1100 degreesC heat-treated samples with the same crystal structure (X-1-Y2SiO5 phase), respectively. However, a significant increase in the overall lifetime (35.21 ns) is observed for the 1300 degreesC annealed 0.5 mol % Ce doped Y2SiO5 sample having a different crystal structure (X-2-Y2SiO5 phase). We found that the decay kinetic is biexponential. It is explained that the fast component arises due to sequential hole-electron capture on the luminescent ions and the slow component arises from isolated ions. Our analysis suggests that modifications of radiative and nonraditive relaxation mechanisms are due to local symmetry structure of the host lattice and crystal size, respectively

Study of photophysical properties of capped CdS nanocrystals

Here, we have examined the role of capping agent on the optical properties of CdS nanoparticles by steady-state and time-resolved photoluminescence (PL) spectroscopy. The estimated particles sizes are 3.45, 2.5 and 2.39 nm for uncapped, capped with silica (SiO2) and thiosalicylic acid (TSA), respectively. The absorption and emission spectra show a clear blue shift to shorter wavelengths in presence of TSA- and SiO2-capped nanoparticles. It is found that the average decay time 〈&#964;〉are 6.24, 4.54 and 2.84 ns for uncapped, capped with SiO2 and TSA nanoparticles, respectively. Our analysis suggests that the hole or the electron is trapped on thiol molecule of TSA or hydroxyl group of SiO2, then radiative recombination of the electron and hole is delayed, resulting in strong quenching of PL efficiency