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Clinical parameters used for hemodynamic assessment and titration of vasopressor therapy in neonates with septic shock have several limitations. Functional echocardiography is an emerging tool for bedside assessment of cardiac function and may be useful for diagnosis of shock and assessing the response to therapy. Data regarding echocardiographic parameters in neonates with shock is lacking. This prospective observational study was conducted in a Level III NICU with the primary objective of comparing echocardiographic characteristics of neonates with septic shock at diagnosis, following fluid boluses, and after maximum inotropic support [A1]. Additionally, we compared these characteristics with those of healthy stable neonates who were gestation and postnatal age-matched. A total of 36 neonates with septic shock and 30 gestation and postnatal age-matched controls were enrolled. The mean (SD) gestation and birth weight of neonates with septic shock were 30.6 (4.0) weeks and 1538 (728) g, respectively. Gram-negative bacilli constituted 78.9% of all isolates. At presentation, there was no significant difference between neonates with shock and controls in terms of ventricular outputs, shortening fraction, ratio of early to late diastolic trans-mitral flow velocity, and myocardial performance indices. The distensibility index of inferior vena cava was higher in neonates with shock compared to controls, (17% vs 10%, (p < 0.01)). Left ventricular output was 209 (92) and 227 (102) ml/kg/min (p = 0.53) and right ventricular output was 427 (203) and 459 (227) ml/kg/min, (p = 0.03), respectively, before and after inotropic therapy. Conclusion: Echocardiographic parameters may not differentiate neonates with septic shock from hemodynamically stable neonates. Neonates with shock associated with predominantly gram-negative sepsis are not able to augment cardiac functions, either at the onset or after administration of inotropes. Trial registration: (CTRI/2017/12/010766). What is known: • For neonates with shock, echocardiography is becoming increasingly popular as an objective method of evaluating hemodynamics. • In healthy preterm neonate, cardiac output has been known to increase in response to altered hemodynamics during states of increased oxygen demand. What is new: • In the setting of septic shock induced by gram-negative organisms, echocardiographic parameters are less likely to assist in the assessment of the response to vasoactive agents. Cytokines, induced by gram-negative organisms, may alter adrenoreceptors in myocardium and vasculature. [ABSTRACT FROM AUTHOR]

In this work, photo- and temperature-dependent electrical properties of thermally deposited WTe2 thin film have been reported. The n-type behaviour of WTe2 film of thickness ~ 122 nm has been observed. The dark conductivity analysis revealed that thermally activated conduction mechanism is responsible for charge carrier transport. In the presence of light, WTe2 shows higher current than dark conditions response towards light with two activation energies of ~ 0.374 eV and 0.692 eV signifying the dominance of bimolecular recombination under light illumination. On–off cycle determined the respective current variation with different light intensities. The fabricated device possesses responsivity ~ 0.36 mA/W and detectivity of ~ 3.2 × 109 Jones. [ABSTRACT FROM AUTHOR]

Germanium telluride (GeTe) is a phase-change material (PCM) from chalcogenide family, which undergoes reversible transition between amorphous and crystalline phase when subjected to optical or electrical pulse. The fast structural reversibility poses GeTe as an ideal material for data storage devices. GeTe is one of the best candidates for non-volatile memory technologies because of its high speed, low power consumption, scalability, data retention, and storage capacity. In this review, we discuss the developments in GeTe PCM, and their working and effect of interface and doping to upgrade their performance for various technological applications. [ABSTRACT FROM AUTHOR]

Indium selenide (InSe), a member of chalcogenide semiconductors, has attracted immense attention due to its wide range of technological applications in solar cells, data storage, switching devices and diodes. In the present study, InSe thin films are deposited using thermal evaporation method, and post-annealing treatment has been performed in vacuum at different temperatures (150 °C, 200 °C, and 250 °C) to induce changes in structural, morphological and optical properties. As-deposited InSe thin film has monoclinic phase, and the crystallinity is found to increase with annealing at 150 °C and 200 °C. The phase transition from crystalline to amorphous phase is achieved with annealing at higher temperature (250 °C). The drastic change in the morphology with annealing temperature is clearly visible in field emission scanning electron microscope (FE-SEM) images. With annealing, the average transmission in the wavelength range of 900–2400 nm increases, and also the value of optical band gap increases from 1.12 to 1.42 eV. The observed change in the transmission and optical band gap is due to change in density of localized and/or delocalized defect states in the forbidden gap with post-annealing treatment. These results show that the post-annealing treatment has significant impact on structural, morphological and optical properties of InSe thin films. [ABSTRACT FROM AUTHOR]

Ge 2 Sb 2 Te 5 (GST) is considered a promising candidate for next-generation data storage devices due to its unique property of non-volatility and low power consumption. In present work, the bulk alloys and thin films of ( Ge 2 Sb 2 Te 5 ) 100 - x Ga x (x = 0, 3, and 10) are prepared using melt quenching and thermal deposition method, respectively. The effect of Ga doping on host composition is investigated by analyzing X-ray diffraction patterns and field emission scanning electron microscope images. From obtained results, it is found that all doped thin films retained the amorphous nature and exhibited uniform and smooth morphology. In Raman spectra, the appearance of a new peak in 10% Ga-doped GST thin film indicated an alteration in the atomic arrangement of host lattice. Transmission spectra revealed the highly transparent nature of all deposited thin films in the near-infrared region. The optical band gap of Ga-doped GST thin film is lower than that of the pure GST thin film which can be correlated with an increase in band tailing, attributed to an increase in localized defect states in the band gap. Due to the pronounced electronegativity difference between the Ga and Te element, new Ga–Te bonds with a higher number of wrong bonds (Ge–Ge, Sb–Sb, and Ge–Sb) are expected to thermally stabilize the amorphous phase. Such results predict the better performance of Ga-doped GST composition for better performance of phase-change random access memory. [ABSTRACT FROM AUTHOR]

Mo-doped MnS thin film of ~ 100 nm thickness has been deposited using the thermal evaporation technique. Structural and morphological properties have been determined. Temperature-dependent electrical properties have been studied under vacuum conditions in the temperature range 173–423 K. Electrical analysis inferred that the fabricated device follows two types of conduction mechanisms, i.e. thermally activated mechanism (251–423 K) with two activation energies (Ea1 ‒ 0.203 eV and Ea2 ‒ 2.214 eV) and variable range hopping (VRH) conduction mechanism (173–243) K. Light on–off cycles shows the switching action and dependence of the device on the incident light intensity. Light intensity-dependent photodetection properties revealed that current increased with an increase in incident light power density, following the power law with γ equal to ~ 2.12. Present work shows that Mo-doped MnS-based fabricated devices possess photoresponsivity (~ 45 mA/W) as well as detectivity (~ 40.5 × 109 Jones). [ABSTRACT FROM AUTHOR]

We retrieved data of ultrasound-guided neonatal internal jugular vein (IJV) cannulations done between November, 2020 and March, 2021. Of the 33 ultrasound-guided IJV cannulation in neonates, 32 were successful with overall success rate of 97%. Median (IQR) number of attempts per insertion was 2 (1,3.5). There were no major complications observed during the insertion of the catheter. In one instance, inadvertent carotid artery puncture was encountered, without significant bleeding. [ABSTRACT FROM AUTHOR]

We conducted an exploratory longitudinal study to evaluate the macronutrient composition of human milk in mothers delivering very preterm infants ≤ 32 weeks over the first 4 weeks of lactation and the association of human milk composition with maternal and neonatal factors A total of 213 human milk samples collected in the morning between 8 am and 12 pm from 60 eligible mothers were analyzed on 7 (n = 60), 14 (n = 60), 21 (n = 52), and 28 (n = 41) days of lactation by infrared transmission spectroscopy. The true protein content decreased significantly over 4 weeks (mean difference (95% confidence interval)) (MD (95% CI)) week 1 and week 4 = 0.2 g (0.037 to 0.363, P = 0.009)). On the contrary, the mean fat and calorie content showed significant increase over time (MD (95% CI)) = − 1.03 g (− 1.719 to − 0.343, P = 0.001) and − 9.0 kcal/dl (− 15.170 to − 2.830, P = 0.001), respectively). There was no difference in the carbohydrate content of human milk over 4 weeks. Macronutrient composition was independent of maternal parity, mode of delivery, pre-pregnancy body mass index, umbilical artery Doppler flows, previous breast feeding experience, neonatal centile status, gestation, and infant's weight at birth. Multiple regression analysis of human milk composition with mother's dietary components showed no significant association. Conclusion: We conclude that in mothers who deliver very preterm infants ≤ 32 weeks, true protein content decreased, fat and calorie content increased, and carbohydrate content remained stable in human milk during first 4 weeks of lactation. Human milk macronutrient composition was independent of various maternal and neonatal factors including maternal body mass index and dietary intake. Trial registration: CTRI/2017/02/007895 What is Known: • Preterm human milk has high temporal and inter-individual variation in the macronutrient composition. What is New: • In mothers who deliver very preterm infants < 32 weeks, true protein content decreases, fat and calorie content increases, and carbohydrate content remains stable in human milk during first 4 weeks of lactation. • Human milk macronutrient composition is independent of various maternal and neonatal factors including maternal body mass index and dietary intake. [ABSTRACT FROM AUTHOR]

We report a versatile and simple approach to obtain nanotubes and nanorods in molybdenum oxide (MoO 3 ) thin films deposited by thermal evaporation, with subsequent post-deposition annealing at different temperatures. The X-ray diffraction patterns inferred a structural transition from amorphous to crystalline phase with annealing at 150 °C or higher temperature. The Fourier transform infrared spectra showed the characteristic vibrations of MoO 3 . The as-deposited amorphous MoO 3 thin film transforms its morphology to nanotubes and then to nanorods with annealing, which may be ascribed to interface-assisted phenomena. A slight decrease of average transmittance in the Visible-NIR region is observed with increase in annealing temperature. The decrease in the optical band gap of annealed thin films anticipated the formation of oxygen vacancies. Thus, the structural, morphological, and optical properties of MoO 3 thin films are found to be influenced by the annealing temperature. The thermally induced nanostructures in molybdenum oxide thin films can be utilized for sensing applications. [ABSTRACT FROM AUTHOR]

Applicability of spinel compounds is mainly governed by cation distribution in them. In the presented study, thermally induced cation ordering is found to influence the emission color of Mg 2 + , Fe 3 + co-doped ZnAl 2 O 4 spinel. Cation distribution is monitored through Mg K-edge, Fe L 2 , 3 -edge, O K-edge X-ray absorption near edge structure spectroscopy and X-ray diffraction analysis using synchrotron radiation. Thermal treatment provided sufficient energy to Zn 2 + , Mg 2 + , Al 3 + and Fe 3 + cations to redistribute themselves on tetrahedral and octahedral sites, and reduce the octahedral distortion, thereby gaining stability. Reduced inversion accompanied by decrease in oxygen vacancies, while increase in tetrahedral and octahedral site vacancies contributed toward more intense blue emission band and quenched yellow band, changing the emission color from bluish-white to blue. Correlation derived between cation ordering and luminescence upon thermal treatment predict Mg 2 + , Fe 3 + co-doped ZnAl 2 O 4 nanophosphors to be useful in thermal sensing applications. [ABSTRACT FROM AUTHOR]

Boron nitride (BN) has encouraged researchers to use it in composite materials due to its different properties. BN-based nanocomposites have been synthesized using a modified chemical method. X-ray diffraction (XRD) results confirmed the formation of hexagonal-BN and nickel oxide (NiO) phases in samples. XRD analysis shows that samples are textured along (100) plane which distorts structure and leads to formation of defect states. The electron density difference between BN and NiO as well as textural growth are two main reasons for variation in diffraction peak intensities. Raman spectroscopic results also revealed that peak intensity and position shifts with increase in NiO content, due to the distortions induced by NiO incorporation confirming the presence of defect states. Field emission scanning electron microscopy (FESEM) results showed that morphology of synthesized nanocomposites varies with increase of NiO concentration. Ultra-violet (UV)-visible results revealed that the absorption edge is red-shifted with NiO content, consequently, the band-gap energy of composites get decreased. Distorted crystal structure and defect states are responsible for variation in structural, morphological as well as optical properties. Results suggested that the nanocomposites can be explored for photodetection as well as gas sensing applications. [ABSTRACT FROM AUTHOR]

Manganese oxide (MnO2) thin films were electrodeposited on stainless steel substrates through galvanostatic mode at different current densities of 2.0 mA cm−2, 1.0 mA cm−2, and 0.5 mA cm−2. Morphology of the films was controlled by controlling current density during deposition. The surface morphology and compositional analysis of deposited films were studied through scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) respectively. SEM images revealed a porous morphology of the deposited films, while discontinuity of film surface was observed for films deposited at higher growth rate. X-ray diffraction patterns for the deposited films revealed a weak orthorhombic crystal system corresponding to the di-pyramidal structure of MnO2. The specific capacitance of MnO2 films, as determined through cyclic voltammetry, was found to range from 90 Fg−1 to 170 Fg−1. The electrochemical impedance spectroscopy (EIS) data was used for obtaining a modified Randles equivalent circuit for identifying the series resistance, charge-transfer resistance, double-layer capacitance, and ion diffusion. Fractal dimensions of the deposited films were determined through image processing software and EIS data. The study also investigates the effect of texture, roughness, and anisotropy of the thin films on their electrochemical capacitive performance. [ABSTRACT FROM AUTHOR]

Hybrid materials exhibit excellent properties than their components. Herein, boron nitride and boron nitride/nickel oxide (BN80/NiO20) nanocomposite films were deposited by the drop-casting method. X-ray diffraction, Raman spectroscopy and field emission scanning electron microscopy techniques have been utilized for determining structural, defect chemistry and morphological properties of deposited films. The structural analysis confirmed the formation of BN and NiO phases. Nelson–Riley Factor analysis and Raman analysis revealed the presence of defect states in BN80/NiO20 film. Electrical properties of films were studied in the presence of various concentrations of ammonia gas molecules at different temperatures. BN80/NiO20 composite film showed higher resistivity in the presence of ammonia gas than pure BN film. Variation of electrical resistivity with ammonia gas concentration has been explained through a proposed model. Also, to obtain the resistivity variation concerning ammonia gas concentrations at different temperatures, the linear regression method was used. This work insight the electrical behavior of composite material at different gas concentrations which opens these materials for exploration towards gas sensing and different functional applications. [ABSTRACT FROM AUTHOR]

Objectives: To compare outcomes of very low birth weight (VLBW) neonates before and after the change in practice for treatment of PDA. Methods: Medical records of VLBW neonates were reviewed. Neonates were categorized in two groups: Period I (January, 2012 to July, 2015) and Period II (August, 2015 to December, 2016). The primary outcome of study was composite outcome of death or broncho-pulmonary dysplasia (BPD). Results: The composite outcome (Death/BPD) was comparable in two groups; adjusted OR (95% CI) 1.1 (0.6, 1.9). Mortality and severe BPD were also comparable. The pharmacological treatment for PDA was required in 8.4% vs 2.6% of VLBW neonates during Period I and II, respectively (P=0.03). Durations of invasive and noninvasive ventilation were comparable during two periods. Conclusion: Restrictive threshold for management of PDA in VLBW neonates may not be associated with increase in morbidities or mortality and possibly would reduce need for pharmacological treatment or surgical ligation. [ABSTRACT FROM AUTHOR]

Solar energy is the extreme realistic solution to regularly growing energy crisis. Several solar energy conversion systems have been in harnessing into useful form of energy. The performance of solar energy devices depends on the properties of nanomaterial used for solar energy conversion. As the primary sources of energy are depleted increasingly and give rise to the energy and environmental crisis for humankind. Therefore, exploration of FeS2 pyrite nanostructures for energy and environment applications are carried out in this review. This review focuses on the synthesis, functionalization as well as applications of FeS2 nanomaterial. The shape and size control have been governed by the synthesis methods such as hydrothermal method, sulfidation, solvothermal method and hot injection method. All these methods are discussed in detail. The review involves overview of FeS2, also outlining the structure, basic magnetic, optical and transport properties. Then the comprehensive study regarding modification of FeS2 nanostructures is also illustrated. The well synthesized FeS2 nanomaterials have been used for basic building blocks of functional systems and their application in photovoltaics and photocatalysis is briefly reviewed. Lastly, various future strategies and trends in these research areas are outlined. [ABSTRACT FROM AUTHOR]

In this study, boron nitride (BN) and its composites with nickel oxide (NiO) have been deposited on glass substrates. Structural, morphological as well as temperature-dependent electrical properties of BN-based nanocomposite films have been investigated. The structural analysis confirmed the phase formation of BN and NiO. X-ray diffraction analysis inferred the presence of defect states in deposited films which may affect the electrical properties. Results revealed that the conductivity of deposited films depends upon composite composition and temperature. A charge transport mechanism for deposited films has been proposed for a better understanding of the transport process. This study provides the insights of temperature dependency of electrical conductivity of deposited films. [ABSTRACT FROM AUTHOR]

The major causes of emergence of multidrug-resistant organisms (MDRO) in neonatal sepsis include empiric antibiotic prescriptions, unregulated use of over-the-counter drugs, high incidence of healthcare associated infections (HAI), lack of awareness about antibiotic stewardship program and under staffing of neonatal intensive care units. In general, mortality due to MDRO sepsis is significantly higher as compared to non MDRO sepsis. Reported morbidities include prolonged use of total parenteral nutrition, need for central venous catheter, invasive ventilation, increased duration of hospital stay and neurologic sequelae. [ABSTRACT FROM AUTHOR]

Defect states in ZnAl2O4 have a significant role in its applicability as a luminescent material. To understand the nature and distribution of defects in its crystal lattice, thermoluminescence (TL) study has been carried out. Excellent TL response is observed from γ- and ultraviolet-irradiated samples at different doses and exposure durations, respectively. Different type of fuels employed in combustion synthesis show a remarkable effect on the trap distribution and hence luminescence properties. Shallow and deep traps are observed in crystals attributed to O− vacancies and F+ centers. The mechanism of trapping, retrapping and recombination have been depicted through schematic band model diagram. X-ray photoelectron spectroscopy indicated the presence of various types of defects specifically AlZn antisite defect, oxygen and zinc vacancies which are further upheld by photoluminescence and Raman spectroscopy. All results when summed up, predict ZnAl2O4 to be a quality material for dosimetry. [ABSTRACT FROM AUTHOR]

This paper reports enhancement in the specific capacitance of iron-doped manganese oxide ( MnO 2) films, potentiostatically deposited on stainless-steel substrates. The properties of deposited films were investigated through cyclic voltammetry and galvanostatic charge/discharge characteristics. The specific capacitance, as determined through cyclic voltammetry and galvanostatic charge/discharge characteristics, respectively, was found to be 248.79 and 277.5 F g - 1 for undoped films, whereas it exhibited an increase with doping and was found to be 449.61 and 487.5 F g - 1 , respectively, corresponding to a dopant concentration of 4 atomic percentage. The electrochemical impedance data were fitted with a modified Randles equivalent circuit to find series resistance, charge-transfer resistance, double-layer capacitance and ion diffusion. According to electrochemical impedance spectroscopy, the enhancement of ion diffusion was found to be the major cause for enhancement in capacitive performance of the films. [ABSTRACT FROM AUTHOR]

Objective: To derive normative data of the distance between optimally placed endotracheal tube tip and arch of aorta by ultrasound in neonates across different weight and gestation. Design: Cross-sectional study. Setting: Tertiary care neonatal intensive care unit from April 2015 to May 2016. Participants: All neonates requiring endotracheal intubation were eligible for the study. Methods: During intubation, insertional length was determined using weight-based formula. The distance between endotracheal tube tip and arch of aorta was measured by ultrasound. Endotracheal tube position was confirmed by chest radiograph. Results: Out of 133 enrolled infants, 101 (75.9%) had optimally placed endotracheal tubes. The mean (SD) distance between endotracheal tube tip and arch of aorta by ultrasound was 0.78 (0.21) cm in infants <1500 g and 1.04 (0.32) cm in infants ≥1500 g. The regression equation to estimate insertional length from weight, crown heel length (CHL), occipito-frontal circumference (OFC), nasal tragus length (NTL) and sternal length (SL) were Wt(kg)+4.95, 0.15×CHL(cm)+0.57, 0.22×OFC(cm)+0.49, 0.82× NTL(cm)+1.24 and 0752×SL(cm)+2.26, respectively. Conclusion: Our study reports normative data of the distance between optimally placed endotracheal tube tip and arch of aorta by ultrasound in neonates. The distance between endotracheal tube tip and arch of aorta increases with increase in weight and gestation. Insertional length correlates strongly with all the anthropometric parameters. [ABSTRACT FROM AUTHOR]

Ge2Sb2Te5 is a potential candidate for various technological applications because of its splendid set of properties. (Ge2Sb2Te5)100−xAgx (x = 0 and 3) bulk alloys and thin films are prepared using melt quenching and thermal evaporation method, respectively. The structural analysis of as-deposited and annealed (at 150 and 160 °C) thin films is accomplished using X-ray diffraction. Phase transition is observed in thin films annealed at 160 °C. The thermal behavior of the samples is investigated using differential thermal analysis (DTA). Crystallization temperature of the bulk alloys is obtained from DTA curve analysis. Activation energy of crystallization has been evaluated using different thermal kinetic approaches: Kissinger, Moynihan and Augis and Benett. It is found that with Ag doping, the crystallization temperature and activation energy of crystallization increased which enhanced the thermal stability of phase change material. [ABSTRACT FROM AUTHOR]

Composition dependent structural and morphological study of nanocrystalline ZnxTe100−x (0, 5, 20, 30, 40, 50) thin films has been performed. The effect of annealing on these properties is also investigated. Nanocrystalline alloys and thin films of ZnTe were prepared using conventional melt quenching technique and thermal evaporation technique, respectively. The prepared thin films were characterized using Field emission scanning electron microscope (FE-SEM), Atomic force microscope (AFM) and Raman spectroscopy. FE-SEM images show that thin films consist of spherical, compact, densely packed and well-connected grains without any cracks, pitfalls, voids or pinholes. 2-D and 3-D AFM images show grain growth with increasing annealing temperature with improvement in crystallinity and average roughness. Raman Spectra show only Te peaks related to A1 and E2 mode, for x = 0. With addition of Zn, ZnTe peaks arises and the presence of 1LO, 2LO and 3LO ZnTe modes are observed. Only ZnTe peaks are observed at x = 50, with diminishing of Te peaks. Annealing effect on Raman spectra and dark conductivity is also reported. [ABSTRACT FROM AUTHOR]

Objective: To improve the usage of expressed breast milk in very low birth weight infants admitted in the neonatal intensive care unit of a tertiary centre in India.Methods: Between April 2015 and August 2016, various Plan-do-act-study cycles were conducted to test change ideas like antenatal counselling including help of brochure and video, postnatal telephonic reminders within 4-6 hours of birth, standardization of Kangaroo mother care, and non-nutritive sucking protocol. Data was analyzed using statistical process control charts.Results: 156 very low birth weight infants were delivered during the study period, of which 31 were excluded due to various reasons. Within 6 months of implementation, the proportion of very low birth weight infants who received expressed breast milk within 48 hours improved to 100% from 38.7% and this was sustained at 100% for next 8 months. The mean time of availability and volume of expressed breast milk within 48 hours, improved gradually from 73.3 h to 20.9 h and 4.7 mL to 15.8 mL, respectively. The mean proportion of expressed breast milk once infant reached a feed volume of 100 mL/kg/day also improved from 61.3% to 82.3%.Conclusion: Quality improvement interventions showed promising results of increased expressed breast milk usage in very low birth weight infants. [ABSTRACT FROM AUTHOR]

Objective: To assess feasibility of ultrasound (USG) evaluation of tip position of central catheter in neonates and to determine agreement between radiograph and USG-based assessments. Methods: This prospective observational study was conducted in a tertiary neonatal intensive care unit from April, 2019 to August, 2019. Point of care USG and radiograph were performed on infants who underwent central line placement. Agreement between the two was determined using Kappa statistics. Results: Of the 141 central catheters insertions performed, USG was performed for 65 central catheters. On USG, catheter tip position could be assessed and defined in 62 (95%) of cases. Of these 62 central lines, 24 (38.7%) were defined as optimally placed on radiograph and 20 (32.2%) were defined as optimally placed on USG. There was excellent agreement between radiographic and USG assessment of catheter tip position [K (95% CI) = 0.86 (0.73–0.99), P < 0.001]. All 38 lines found to be mal-positioned on radiograph were assessed as suboptimal on USG as well. Conclusion: Point of care USG has excellent agreement with radiography for confirming central line tip position. [ABSTRACT FROM AUTHOR]

Present paper reports the effect of deposition temperature on structure and electrical conduction mechanism of ZnSe thin films. Films have been fabricated on glass substrates using condensation technique. The depositions have been performed in presence of Ar at various substrate temperatures (298-373 K). X-ray diffraction (XRD) studies reveal hexagonal structure with texture changing from (002) to (102) on increasing substrate temperature. The crystallite size (6.1-8.4 nm), strain (− 0.0133 to − 0.00748 lin−2 m−4), dislocation densities (1.857 × 1016-1.015 × 1016 lin m−2) and stacking fault probability (0.0038-0.0041) have been calculated from XRD data. The optical gap (2.75-3.00 eV), refractive index (2.38-2.48) and ionicity (0.425-0.446) have been calculated using transmission measurements. The dark-conduction and photo-conduction behaviours have been studied in temperature range 253-358 K. The two activation energies of dark conduction have been explained using different models. The conduction mechanism has been identified based on Seto’s model of thermionic emission. The barrier height (0.17-0.28 eV), impurity concentration (1.26 × 1020-3.18 × 1020 cm−3) and surface states density (1.05 × 1014-2.15 × 1014 cm−2) have also been calculated. [ABSTRACT FROM AUTHOR]

In present study, dependence of structural and optical properties of nanocrystalline Zn40Te60 (ZnTe) thin films on vacuum thermal annealing has been investigated. ZnTe alloy was prepared by melt quenching technique and thermally evaporated on cleansed glass substrates to deposit thin films. These films were annealed in vacuum (∼1×10-3 mbar) for an hour at three different temperatures 100, 200 and 300 °C. X-ray diffraction results revealed the presence of cubic ZnTe phase in all the films along with some hexagonal Te phase. The crystallite size of ZnTe thin films improved on annealing with larger size at elevated temperatures (from 32 to 80 nm). Micro strain and dislocation density reduced owing to improvement in crystallinity after annealing. The IR transmittance increased with increase in annealing temperature. Field emission scanning electron microscopy images suggested the formation of smooth and uniform thin films with thickness of ∼ 480 nm. Optical properties revealed the decrease in transmittance and absorption edge shift due to crystallinity improvement on annealing. The optical band gap decreased from 1.37 to 0.91 eV on annealing. Experimental results show that thermal annealing has significant impact on structural and optical properties of ZnTe thin films. [ABSTRACT FROM AUTHOR]

Size, shape and structure are considered to have significant influence on various properties of semiconducting nanomaterials. Different properties of these materials can be tailored by controlling the size. Size-controlled CdSe crystallites ranging from ∼ 04 to 95 nm were deposited by inert gas-condensation technique (IGC). In IGC method, by controlling the inert gas pressure in the condensation chamber and the substrate temperature or both, it was possible to produce nanoparticles with desired size. Structure and crystallite size of CdSe thin films were determined from Hall-Williamson method using X-ray diffraction data. The composition of CdSe samples was estimated by X-ray microanalysis. It was confirmed that CdSe thin film with different nanometer range crystallite sizes were synthesized with this technique, depending upon the synthesis conditions. The phase of deposited CdSe thin films also depend upon deposition conditions and cubic to hexagonal phase transition was observed with increase in substrate temperature. The effect of crystallite size on optical and electrical properties of these films was also studied. The crystallite size affects the optical band gap, electrical conductivity and mobility activation of nanocrystalline CdSe thin films. Mobility activation study suggested that there is a quasi-continuous linear distribution of three different trap levels below the conduction band. [ABSTRACT FROM AUTHOR]

In this work, the effect of visible light on the structural, morphological and optical properties of $$(\hbox {Ge}_2\hbox {Sb}_2\hbox {Te}_5)_{100-x}\hbox {Ag}_x$$ ( $$\hbox {x} = 0, 1$$ and 3) thin films prepared by thermal evaporation was studied. Deposited thin films were exposed to visible light of intensity $$10^{4}$$ and $$10^{5}$$ Lux for the duration of 2, 4, 8 and 20 h. Prepared samples were characterized with X-ray diffraction (XRD), Scanning electron microscope (SEM) and UV-Vis-NIR spectrophotometer. The amorphous nature of as-deposited and visible light exposed thin films was confirmed by XRD. The SEM images did not show significant change in the morphology of thin films after visible light exposure. The optical transmission of as-deposited and exposed thin films was measured by UV-Vis-NIR spectrophotometer in the wavelength range of 500-3300 nm. Optical transmission was used to calculate the absorption coefficient and optical band gap. Photo-darkening (decrease in optical band gap) with light exposure was observed in $$(\hbox {Ge}_2\hbox {Sb}_2\hbox {Te}_5)_{100-x}\hbox {Ag}_x$$ ( $$\hbox {x} = 0, 1$$ and 3) thin films. Photo-darkening may be attributed to the enhanced lone pair-lone pair interactions which broaden the valence band and hence decrease the optical band gap. Thus, change in optical parameters is because of change in local structure of deposited thin films. [ABSTRACT FROM AUTHOR]

SnO is a promising material for optoelectronic, catalytic and sensing applications and is highly sensitive to the small amount of impurities that can change its properties drastically. In the present work, co-precipitation method was employed to synthesize pure and Zn-doped SnOnanostructures. The effect of Zn doping (1, 3 and 5% molar ratio) on crystallographic and spectroscopic properties of SnO nanostructures has been studied. The X-ray diffraction results revealed that SnO possesses tetragonal rutile crystal structure with predominant (110) plane and the same structure was retained after doping with Zn. Raman shifts also confirmed the typical feature of the tetragonal rutile phase in all samples. Fourier transform infrared spectra revealed stretching mode of Sn-O bond and vibrational mode of O-Sn-O bond complementing the Raman spectroscopy results. Field emission scanning electron micrographs confirmed the variation in morphology of synthesized samples with Zn-dopant concentration. High-resolution transmission electron micrographs showed that the synthesized nanostructures were nearly spherical and average particle size varies between ~20-26 nm. UV-Visible results revealed that the band gap of the synthesized SnO nanoparticles increased with increase in Zn content. Photoluminescence spectroscopic results showed that emission intensity increased with increase in Zn content. The increased intensity of emission peaks may be ascribed to the development of defect states in the band gap of Zn-doped SnO nanoparticles. [ABSTRACT FROM AUTHOR]

We studied the structural and optical properties of SbSe (x = 0 and 5) thin films (thickness ~320 nm) deposited by thermal evaporation. The structural properties and stoichiometry of prepared samples were studied by X-ray diffraction and energy dispersive X-ray spectroscopy, respectively. With Sb addition, average coordination number increased and number of lone pair of electron, cohesive energy, fraction of floppy modes decreased. The transmission spectrum (450-2700 nm) was used to calculate the thickness, refractive index and extinction coefficient by Swanpoel's method. Refractive index and extinction coefficient were used to obtain linear and non linear optical parameters. The refractive index, extinction coefficient, volume energy loss function, surface energy loss function, dielectric constant, dielectric loss function, optical conductivity and non-linear optical parameters increased with Sb doping to a-Se. The increase in optical parameters was due to decrease in optical band gap. The decrease in optical band gap was due to increase in density of localized states in mobility gap. The results revealed that with addition of Sb, the system becomes more stable, relaxed and rigid. [ABSTRACT FROM AUTHOR]

Thin films of (GeSbTe)Ag (x = 0, 1, 3, 5 and 10) were deposited using thermal evaporation technique. X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy was used to confirm the amorphous nature, uniformity and chemical compositions of deposited films respectively. Transmission spectra divulged the highly transparent nature of films in near infra red region. The average transmission in near infra red region and optical band gap (estimated by Tauc's plot) was increased with Ag doping upto x = 3 while it decreased for higher values of x. The increase in transmission and optical band gap was attributed to the reduction in density of localized states and vacancies. However, the decrease in the transmission and optical band gap is due to the increase in distortion of the host GeSbTe lattice because Ag is doped at the expense of Ge, Sb and Te. The increased optical band gap could be utilized to reduce threshold current which enhances switching speed in phase change materials. [ABSTRACT FROM AUTHOR]

The article presents a study on the optical properties of a-(Ge20Se80)0.96Ag0.04 thin films before and after proton irradiation. Optical parameters such as refractive index, absorption coefficient, oscillator strength, oscillator energy and optical gap have been calculated. It has been observed that the optical parameters change after the proton irradiations.

We report, for the first time, the influence of oxygen vacancies on band structure and local electronic structure of SrZnO 2 (SZO) nanophosphors by combined first principle calculations based on density functional theory and full multiple scattering theory, correlated with experimental results obtained from X-ray absorption and photoluminescence spectroscopies. The band structure analysis from density functional theory revealed the formation of new energy states in the forbidden gap due to introduction of oxygen vacancies in the system, thereby causing disruption in intrinsic symmetry and altering bond lengths in SZO system. These defect states are anticipated as origin of observed photoluminescence in SZO nanophosphors. The experimental X-ray absorption near edge structure (XANES) at Zn and Sr K-edges were successfully imitated by simulated XANES obtained after removing oxygen atoms around Zn and Sr cores, which affirmed the presence and signature of oxygen vacancies on near edge structure. [ABSTRACT FROM AUTHOR]

The article Neonatal Sepsis: Mortality and Morbidity in Neonatal Sepsis due to Multidrug-Resistant (MDR) Organisms: Part 1, written by Chand Wattal, Neelam Kler, J. K. Oberoi, Anurag Fursule, Anup Kumar and Anup Thakur, was originally published electronically on the publisher's internet portal (currently SpringerLink) on 11 December 2019 with open access. [ABSTRACT FROM AUTHOR]