Correlation between the particle size, structural and photoluminescence spectra of nano NiCr2O4 and La doped NiCr2O4 materials.

Nano NiCr2O4 undoped and La doped NiCr2O4 nanorods array were successfully prepared by solution based conventional method[sbcm]. The synthesized samples were characterized by the diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy for finding optical properties. Further, the samples structure confirmed by Fourier transforms infrared (FTIR), and X-ray diffraction (XRD)techniques. High-resolution transmission electron microscopy (HRTEM) analysis revealed the attachment of NiCr2O4 nanorods on surface of nanoparticles. From the results, it was found that the reaction time, band gap energy, and particle size strongly influenced by changing the concentration of La in NiCr2O4. This work is notable for its examination of the impact of the precursor on the optical and structural characteristics of samples of La-doped and undoped NiCr2O4. This was the first time the investigation had been done. The average particle size of the La-doped and undoped NiCr2O4 samples is between 16 and 24 nm.

Synthesis, Structure, Morphology, Element composition, Electrochemical, and Optical studies of Zn0.98-XMn0.02CeX Quantum dots.

Quantum dots (QDs) are semiconductors whose size falls in a range between 1 and 10 nm; they are generally known as zero-dimension materials. It finds various applications in optical industries including light-emitting diodes, display technology, imaging, and labelling. ZnS is one of the excellent QDs in its class of II-VI semiconductors. In this paper, It is reported that the preparation of Mn-doped ZnS and Mn, Ce co-doped ZnS QDs using facile co-precipitation technique. XRD and HR-TEM results confirmed the cubic structure, particle size, and phase of the synthesized particles, and the crystallite is measured as âˆ¼ 2 nm. The surface morphology, elemental analysis, and FT-IR spectra revealed the purity of the samples and confirmed the presence of dopants as expected. Cyclic voltammetry studies expressed the electrochemical behaviour of the samples, which increased as a function of Ce3+ doping concentration. UV-visible absorbance and transmittance spectra disclosed the optical characteristics of the samples. A wide band gap (4.02 eV) was received for 2% Ce-doped Zn: MnS QDs. Week Blue and strong yellow emissions were received for 4% Ce-doped Zn:MnS QDs. Whereas, high intensity red-emission was received for 2% Ce-doped Zn:MnS QDs. The different colour emissions are discussed in terms of defects produced.

Synthesis of MoS2/Mg(OH)2/BiVO4 hybrid photocatalyst by ultrasonic homogenization assisted hydrothermal methods and its application as sunlight active photocatalyst for water decontamination.

In this work, MoS2/Mg(OH)2/BiVO4 ternary hybrid photocatalyst was synthesized by sonicated precursor mixture to the hydrothermal procedure to generate a highly efficient solar light-induced and simply recyclable photocatalyst. The obtained hybrid was confirmed by the characteristic peaks of MoS2/Mg(OH)2/BiVO4 observed in X-ray diffraction (14.31°/18.62°/28.18°), infrared spectra (465/445/679 cm-1), ultraviolet-visible spectra (636/683/639 nm) studies, and the band-gap narrowing (2.62/2.44/2.25 eV). The morphological structure of MoS2 (rod), Mg(OH)2 (particles), and BiVO4 (random aggregates) were turned into MoS2/Mg(OH)2/BiVO4 hierarchical nanosheets that coexisted with particles. The photodegradation experiments of the photocatalysts were assessed by using Congo Red (CR), Malachite Green (MG) and Textile Industry Effluent (TIE) as the model pollutant under direct sunlight. The photocatalytic efficiency of the hybrids was noticeably 2.1 to 2.3 times higher than that of the individual components. Photocurrent response test indicate that MoS2/Mg(OH)2/BiVO4 ternary hybrid nanocomposites photocatalysts had a more effective electron/hole pair separation than individual and binary composite photocatalysts. The mechanism of photodegradation of MoS2/Mg(OH)2/BiVO4ternary hybrid photocatalysts was investigated and discussed.

The role of sodium dodecyl sulfate mediated hydrothermal synthesis of MoS2 nanosheets for photocatalytic dye degradation and dye-sensitized solar cell application.

The novel properties and exciting behavior of two-dimensional nanosheet-based materials have piqued the interest of research all over the world. In this study, bulk molybdenum disulfide (bulk MoS2) and sodium dodecyl sulfate-mediated molybdenum disulfide nanosheets (MoS2-SDS NS) were synthesized via a facile sonication and hydrothermal process. The findings from the characterization revealed that the addition of sodium dodecyl sulfate (SDS) surfactant reduces the crystal phase and changes the structural morphology of bulk MoS2. Furthermore, the photocatalytic and photovoltaic performance of bulk MoS2 and MoS2-SDS NS were also investigated. The results show that by using methylene blue dye, the photocatalytic efficiency increased from 56.30% to 91.84% at 150 min under UV-Visible light irradiation, and the photo-conversion efficiency (PEC (%)) of the dye-sensitized solar cell increased from 1.47% to 3.81% for bulk MoS2 and MoS2-SDS NS, respectively. Finally, we discussed in-depth the effect of SDS surfactants on MoS2, which can improve their photovoltaic and photocatalytic performance.

Brain regional pharmacokinetics following the oral administration of curcumagalactomannosides and its relation to cognitive function.

OBJECTIVE: Though a number of bioavailable formulations of curcuminoids have been reported and available commercially as nutraceuticals for brain health, systematic informations on their blood-brain-barrier permeability and brain tissue distribution have not been reported. The present study was aimed to investigate the brain regional pharmacokinetics of curcuminoids following both single dose and repeated dose oral administration of a self-emulsifying food-grade formulation of curcuminoids using fenugreek galactomannan hydrogel scaffold as 'curcumagalactomannosides' (CGM), and its influence on cognitive functions in comparison with unformulated natural curcuminoids (NC) in Wistar rats. METHODS: CGM was given to animals in single dose (100 mg curcuminoids/kg b. wt.) and repeated dose (100 mg curcuminoids/kg b. wt. for 28 days) and the concentration of total curcuminoids at various parts of brain was evaluated at different time points using Ultra-performance liquid chromatography/electrospray ionization triple quadruple tandem mass spectroscopy (UPLC-ESI-MS/MS) system. Another set of animals were also fed with CGM at single dose (100 mg curcuminoids/kg b. wt.) and repeated dose (100 mg curcuminoids/kg b. wt. for 28 days) and the behavioural studies were conducted using open field test and radial arm maze. RESULTS: UPLC-ESI-MS/MS analyses of plasma revealed significant absorption of unconjugated (free) curcuminoids upon both single and repeated dose administration of CGM with maximum concentrations of 173.34 ± 27.12 ng/mL and 223.22 ± 32.73 ng/mL, respectively. Further analysis of brain tissues demonstrated significant blood-brain-barrier permeability. Brain regional pharmacokinetics (AUC, Cmax and t1/2) indicated a relative distribution order of hippocampus > striatum > cerebellum > cerebral cortex > brain stem. Supplementation of CGM for 28 days also offered significant (p < 0.05) improvement in locomotor activity and reduction in spatial memory errors as compared to NC. The NC treatment also improved the behaviour better than the vehicle-treated group. CONCLUSION: CGM could distribute significant amount of free curcuminoids, in brain especially in the hippocampus at both single and repeated dose administration with an elimination half-life of 2.6 h. CGM also showed a positive impact in behaviour of animals in comparison with normal unformulated curcuminoids.

Enhanced visible light-driven photocatalytic performance of CdSe nanorods.

Cadmium selenide (CdSe) semiconductor nanorods are prepared in hydrothermal process using hydrazine hydrate (N2H4.H2O) and ammonia (NH3.H2O) as reducing agents. The reaction time is increased to 7 h and the amount of hydrazine hydrate used is also increased to 15 mL which have resulted in diminished stacking faults in the CdSe nanorods prepared. The crystal structure, morphological variations, and size of the prepared CdSe nanorods are examined by XRD analysis. The crystalline size of the CdSe nanorods is 20-30 nm in diameter. HRTEM images reveal the formation of high order CdSe nanorods of the length about 25-40 nm. The bandgap in the CdSe nanoparticles is determined to be 2.17 eV. The peak at 595 nm in photoluminescence (PL) spectrum indicates oxygen vacancy defects in the prepared CdSe sample. The variation of dielectric properties with respect to temperature and frequency of pelletized CdSe is studied. High photocatalytic efficiency (98%) of catalyst/H2O2 is also achieved for decomposition of Rhodamine-B dye.

Complications related to peri-operative transoesophageal echocardiography - a one-year prospective national audit by the Association of Cardiothoracic Anaesthesia and Critical Care.

Previous studies on the safety of peri-operative transoesophageal echocardiography seem to suggest a low rate of associated morbidity and mortality. That said, there has been a paucity of prospective multicentre studies in this important area of clinical practice. We carried out a one-year prospective study in 2017, co-ordinated by the Association of Cardiothoracic Anaesthesia and Critical Care, to determine the rate and severity of complications associated with peri-operative transoesophageal echocardiography in anaesthetised cardiology and cardiac surgical patients. With the help of clinicians from 28 centres across the UK and Ireland, we recorded the total number of examinations conducted in anaesthetised patients during the study period. All major complications at each centre were prospectively reported and recorded. Of the 22,314 examinations, there were 17 patients diagnosed with a major complication which caused either palatal injury or gastro-oesophageal disruption. This corresponds to an incidence of 0.08% (95%CI 0.05-0.13%) or approximately 1:1300 examinations. There were seven deaths reported during the study period which were directly attributed to these complications, corresponding to an incidence of 0.03% (95%CI 0.01-0.07%) or approximately 1:3000. These figures are higher than previously reported and suggest a high probability of death following the development of a complication (~40%). Most complications occurred in patients without known risk factors for transoesophageal echocardiography associated gastro-oesophageal injury. We suggest clinicians and departments review their procedural guidelines, especially in relation to probe insertion techniques, together with the information communicated to patients when the risks and benefits of such examinations are discussed.

Synthesis of titanium oxide nanoparticles using Aloe barbadensis mill and evaluation of its antibiofilm potential against Pseudomonas aeruginosa PAO1.

Titanium dioxide nanoparticles (TiO2-NPs) were synthesized using the aqueous leaf extract of Aloe barbadensis as a reducing and fabricating agent. The biosynthesis of the TiO2-NPs was initially confirmed by UV-vis spectroscopy. Based on the HRTEM and FESEM analysis, the biosynthesized NPs were found to be polydispersed and predominantly spherical in shape, with an average size of ~20 nm. A sharp and strong characteristic peaks of titanium (Ti) and oxygen (O) observed in the EDS pattern confirmed the synthesis of the TiO2-NPs. The FTIR spectroscopy suggested the presence of terpenoids, flavonoids and proteins which might be responsible for the biosynthesis and fabrication of the TiO2-NPs. The crystalline nature of the synthesized TiO2-NPs constituting of a mixture of brookite, anatase, and rutile phases was indicated by the XRD pattern. The spectral window around 180-1000 cm-1 covered the high-frequency Raman spectra of the TiO2-NPs. The Raman vibrational spectrum showed four Eg modes centered at 197.84, 399.24, 514.50, and 641.58 cm-1 representing the anatase phase of TiO2-NPs. The strongest and broadened peak of anatase was observed at the frequency of 641.58 cm-1. The metabolic activity of P. aeruginosa exposed to the MIC of TiO2-NPs was measured based on the reduction of tetrazolium salt by the dehydrogenase enzyme, produced by the metabolically active bacterial cells. The reduction in TTC was evident from the appearance of a red colored formazan in the solution. A noticeable suppression in the cell viability by 30.76 ±â€¯3.96% of P. aeruginosa in the biofilm mode was found in presence of TiO2-NPs. Furthermore, the Minimum Inhibitory Concentration (MIC) of TiO2-NPs exhibited profound antibiofilm activity against P. aeruginosa by effectively preventing the adherence of the planktonic cells to the substratum. Thus, these NPs may be employed in controlling bacterial infections associated with biofilm.

Preparation, Characterization and Structure Prediction of In2SnO3 and Spectroscopic (FT-IR, FT-Raman, NMR and UV-Visible) Study Using Computational Approach.

Unadulterated and scorch stage In2SnO3 nanopowder is effectively arranged with the doping proportion of 80-20% (In2O3-Sn) by simple sol-gel combustion direction. The material is characterized by XRD measurements and their geometrical parameters are compared with calculated values. The FT-IR and NMR spectra are recorded in both bulk and nanophase and FT-Raman spectrum is recorded in bulk phase and the fundamental frequencies are assigned. The optimized parameters and the frequencies are calculated using HF and DFT (B3LYP, B3PW91 and MPW1PW91) theory in bulk phase of In2SnO3 and are compared with its nanophase. The vibrational frequency pattern in nanophase gets realigned and the frequencies are shifted up and down little bit to the region of spectra when compared with bulk phase. The UV-visible spectrum is simulated and analyzed. The frontier molecular orbital analysis has been carried out and the values of the HOMO-LUMO bandgap (Kubo gap) explore the optical and electronic characteristics of the In2SnO3. Structural studies by XRD showed the crystallite sizes of the particles. The atomic arrangement in the grain boundary seems to be somewhat different from regular periodic arrangement whereas inside the grain there is a good periodic arrangement of atoms. Above 10 mol% Sn ions, 15 mol% Sn ions, 20 mol% Sn ions to 50 mol% Sn ions form correlated clusters, 20 mol% Sn ions which lead to broadening. These EPR spectra were formed to contain two different components, one from the single isolated ions and the other from the clusters. The transition is observed for different composition increase with decreasing grain size.

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.

Synthesis of water-soluble and bio-taggable CdSe@ZnS quantum dots.

Many synthesized semiconductor QDs materials are formed using trioctylphosphine oxide (TOPO) but it requires high temperature, is very expensive and is also hydrophobic. Our study deals with selective syntheses of CdSe and core-shell CdSe/ZnS quantum dots (QDs) in aqueous solution by a simple heating and refluxing method. It is more hydrophilic, needs less temperature, is economically viable and is eco-friendly. Bio-ligands, such as thioacetamide, itaconic acid and glutathione, were used as stabilizers for the biosynthesis of QDs. A simplified aqueous route was used to improve the quality of the colloidal nanocrystals. As a result, highly monodisperse, photoluminescent and biocompatible nanoparticles were obtained. The synthesized QDs were characterized by XRD, FTIR, confocal microscopy, ultraviolet (UV) absorption and photoluminescence (PL). The size of synthesized QDs was observed as 5.74 nm and the core-shell shape was confirmed by using XRD and confocal microscopy respectively. The QD nanoparticles showed antibacterial activity against pathogenic bacteria. The QDs could be applied for biological labelling, fluorescence bio-sensing and bio-imaging etc.

Poliomyelitis trends in Pondicherry, south India, 1989-91.

STUDY OBJECTIVES: To assess the poliomyelitis trend, including study of the epidemiological features, and to correlate this with the immunisation coverage of infants. DESIGN: Three annual lameness surveys in children aged 0-60 months employing cluster sampling methods and a series of five cross sectional surveys of immunisation coverage in children aged 12-23 months of age were undertaken. SETTING: Pondicherry, India, 1988-92. SUBJECTS: More than 10,000 children in the age group of 0-60 months took part in the three annual lameness surveys and samples of 210 children aged 12-23 months were covered each year in immunisation coverage surveys. MEASUREMENTS AND MAIN RESULTS: Altogether 50 of 11,461, 24 of 10,093, and 17 of 11,218 children surveyed during 1989, 1990, and 1991 respectively had become lame as a result of poliomyelitis, giving prevalences of 4.4, 2.4, and 1.5 per 1000 children for the three surveys. The corrected prevalences of poliomyelitis were 5.9, 3.2, and 2.0 per 1000 children during 1989, 1990, and 1991 respectively. The proportion of cases aged up to 36 months fell from 48% in 1989 to 12.5% in 1990 and 6% in 1991. The age at onset was less than 1 year in most. The median age at onset was 10.7 months. About 54% of the affected children had received three doses of oral poliomyelitis vaccine (OPV) before the onset of paralysis. In 1988 immunisation coverage for the third dose of OPV was 91% and in 1992 it was 97.6%. The drop out rate for the first versus the third dose of OPV fell from 6.3 in 1988 to 1.9% in 1992. CONCLUSION: Three successive annual lameness surveys showed that poliomyelitis was declining between 1989 and 1991. Five immunisation coverage surveys conducted from 1988 to 1992 showed high initial coverage followed by an improvement in the form of almost universal coverage for OPV.

Paralytic poliomyelitis in children under 6 years in Pondicherry: a community survey.

STUDY OBJECTIVES: To assess the amount of poliomyelitis and its epidemiological features including risk factors. DESIGN: This was a retrospective study of cases of paralytic poliomyelitis among children 0-6 years of age. SETTING: Pondicherry, India, 1983-89. SUBJECTS: A total of 47,960 children aged less than 6 years. MEASUREMENTS AND MAIN RESULTS: In 1989, 469 field workers undertook a door to door survey of children 0-6 years old to identify those with limb paralysis. This was followed by clinical examination to establish the cause, supplemented by case notes held by the Child Development Services. Altogether 203 cases of limb paralysis were identified, 188 of which were judged a result of paralytic poliomyelitis. The prevalence of poliomyelitis in 1989 was 3.9/1000 among children below 6 years of age. There was a male preponderance with a male:female ratio of 1.4:1. The prevalence was least in infants (1/1000) and highest in children aged 2 to 3 years (6.4/1000). The age at onset was less than 12 months in 42% of cases and less than 3 years in 98%. The median age at onset was 13.4 months. Time series analysis showed a high occurrence of cases from May to September between 1983 and 1989. The legs were affected in 97%. About 41% of children had received three doses of oral polio vaccine. There was a history of intramuscular injection, possibly provoking a paralytic attack, in 54% of cases. CONCLUSION: This retrospective community study involving the staff of the Integrated Child Development Services provided valid data about poliomyelitis with little additional cost and minimum training. Because the study covered a whole population of children under 6 years, rather than a sample, the data will help in monitoring and surveillance of poliomyelitis and also in planning strategies for effective control.

Community experience for medical students.

This article outlines the features of community postings for medical students in their second clinical year at the Jawaharlal Institute of Postgraduate Medical Education and Research, in Pondicherry, India. Their exposure to the realities of preventive and social medicine in the field clearly helps them to cope with what would otherwise be only theoretical knowledge.

Infant mortality in Pondicherry--an analysis of a cohort of 8185 births.

Infant mortality rate is one of the 12 global indicators for monitoring Health for All. Reliable data on infant mortality are not available for the majority of developing countries including India. To plan strategies for bringing down the rate and, later, to evaluate them, 'Cause Specific Rates' would be necessary. Pondicherry has achieved low rates of infant mortality. A study was conducted in the Anganwadis of Pondicherry to determine the causes of infant deaths. The 8185 children born between 1-4-1987 and 31-3-1988 in Pondicherry formed the study group. The Anganwadi workers collected information on the cause of death for the 222 children dying within the first year. The infant mortality rate was 27.1 per 1000 live births. Acute respiratory infections and diarrheal diseases accounted for 45% of the deaths.