Fluorescence Study of Pr3+ Doped CdS Nanoparticles and its Applications in Sensors and Detectors

Fluorescence spectra of Pr3+ doped CdS nanoparticles, synthesized by chemical precipitation method, have been recorded at room temperature. The synthesized particles are nearly spherical shaped and the grain size is decreased with the increase in Pr3+ concentration. The chemical identity of the nanoparticles was confirmed by EDAX spectrum, the absorption peaks was confirmed by FTIR spectrum and then the recorded values were compared with the CIE diagram. The oscillator strengths of the 4f ↔ 4I transitions are parameterized in terms of three phenomenological Judd-Ofelt intensity parameters Ωλ (λ = 2, 4 and 6). Using the fluorescence data and these Ωλ parameters, theoretical and experimental study of various radiative properties viz., spontaneous emission probability (A), radiative life time , fluorescence branching ratio and stimulated emission cross-section were evaluated. The values of these parameters indicate that 3P0→ 3H4 transition can be considered to be good laser transition in the visible colour region. Also, excitation with 493 nm, leads to similar blue regions. The synthesized Pr3+ doped CdS nanomaterials could be useful for sensing and detecting devices, particularly for temperature sensing measurement and bio-sensing detection.

Gas Sensing Properties of PLD Grown 2D SnS Film: Effect of Film Thickness, Metal Nanoparticle Decoration, and In Situ KPFM Investigation

This study employs novel growth methodologies and surface sensitization with metal nanoparticles to enhance and manipulate gas sensing behavior of two-dimensional (2D)SnS film. Growth of SnS films is optimized by varying substrate temperature and laser pulses during pulsed laser deposition (PLD). Thereafter, palladium (Pd), gold (Au), and silver (Ag) nanoparticles are decorated on as-grown film using gas-phase synthesis techniques. X-ray diffraction (XRD), Raman spectroscopy, and Field-emission scanning electron microscopy (FESEM) elucidate the growth evolution of SnS and the effect of nanoparticle decoration. X-ray photoelectron spectroscopy (XPS) analyses the chemical state and composition. Pristine SnS, Ag, and Au decorated SnS films are sensitive and selective toward NO2 at room temperature (RT). Ag nanoparticle increases the response of pristine SnS from 48 to 138% toward 2 ppm NO2, which indicates electronic and chemical sensitization effect of Ag. Pd decoration on SnS tunes its selectivity toward H2 gas with a response of 55% toward 70 ppm H2 and limit of detection (LOD) < 1 ppm. In situ Kelvin probe force microscopy (KPFM) maps the work function changes, revealing catalytic effect of Ag toward NO2 in Ag-decorated SnS and direct charge transfer between Pd and SnS during H2 exposure in Pd-decorated SnS.

A magnetic field augmented ultra-thin layer chromatography coupled surface enhanced Raman spectroscopy separation of hemozoin from bacterial mixture

Malaria is considered as one the most widespread disease with highest possibility of co-infection at all levels of the disease prognosis. Rapid detection and discrimination of malaria from other co-infections remains a challenge. Hemozoin is a metabolic biproduct of malaraia possessing paramagnetic property due to presence of iron at its centre. Here, we report a label free, rapid and highly sensitive magnetic field based ultra-thin layer chromatography (UTLC) coupled with surface enhanced Raman spectroscopy (SERS) technique for detection and separation of hemozoin from a bacterial mixture. Highly optimized silver nanorods chip fabricated using glancing angle deposition (GLAD) is explored for the UTLC-SERS separation. These chips possessing channel like characteristic and high surface to the volume ratio serve as excellent UTLC plates. The magnetic nature of hemozoin has been exploited for its separation from the mixture of P. aeruginosa (Gram-negative) and S. aureus (Gram-positive) by allocating a 0.6 T magnet over the UTLC flow setup. The solvent front migrated approximately to a distance of 13 mm from the sample point due to the magnetic environment. Spatially resolved SERS data was collected along the mobile phase and separation of mixture was confirmed. Further, staining of hemozoin, P. aeruginosa and S. aureus was done using methylene blue, acridine orange and rhodamine 6 G respectively. The separation was confirmed for the stained analytes. The present developed method provides plate height as low as 18 µm and hemozoin detection limit as <10 parasites/mL. Therefore, we establish a highly specific and sensitive technique capable of separating small amounts of bioanalytes, aiding in the removal of co-infections from the disease at a very early stage of infection.

Ag2Se Nanorod Arrays with Ultrahigh Room Temperature Thermoelectric Performance and Superior Mechanical Properties

Ag₂Se is an intriguing material for room-temperature energy harvesting. Herein, we report the fabrication of Ag₂Se nanorod arrays by glancing angle deposition technique (GLAD) followed by simple selenization in a two-zone furnace. Ag₂Se planar films of different thickness were also prepared. The unique tilted Ag₂Se nanorod arrays show excellent zT = 1.14 ± 0.09 and a power factor of 3229.21 ± 149.01 μW/m-K², respectively, at 300 K. The superior thermoelectric performance of Ag₂Se nanorod arrays compared to planar Ag₂Se films could be ascribed to the unique nanocolumnar architecture that not only facilitates efficient electron transport but also significantly scatters phonons at the interfaces. Furthermore, the nanoindentation measurements were performed to explore mechanical properties of the as-prepared films. The Ag₂Se nanorod arrays showed hardness values of 116.51 ± 4.25 MPa and elastic modulus of 10,966.01 ± 529.61 MPa, which are lowered by 51.8 and 45.6%, compared to Ag₂Se films, respectively. The synergetic dependence between the tilt structure and thermoelectric properties accompanied with the simultaneous improvement in mechanical properties opens a new avenue for the practical applications of Ag₂Se in next-generation flexible thermoelectric devices.

A SERS based clinical study on HIV-1 viral load quantification and determination of disease prognosis

In resource limited settings, a cost-effective point-of-care diagnostic testing possessing the characteristics of detecting the minimum viral load of a malady like human immunodeficiency virus (HIV) acquired immune deficiency syndrome (AIDS) is a pressing priority. The present work describes a novel, rapid and field-deployable method using surface enhanced Raman spectroscopy (SERS) for detection and prognosis of HIV positive clinical samples, in seven different viral load ranges varying between 200 and 1 million copies/ml. A relationship between the increasing and decreasing intensity peaks of HIV-1 was also established for quantitation efficacy of the handheld tool. Three different types of SERS substrates: single arm Ag nanorods, double arm Ag nanorods and Au sputtered single arm Ag nanorods were used and the obtained data was compared for the three substrates. It was demonstrated that maximum enhancement was obtained for Au sputtered Ag nanorods. Rigorous coupled wave analysis (RCWA) simulations were performed to study the 'hotspots' in three different SERS substrates. Further, to explore the utility of our platform and to differentiate between the clade specific X4 and R5 tropism, their corresponding SERS spectra were studied using HIV-1 strains belonging to four different HIV-1 subtypes (A, B, C and D) which showed a clear distinction, implying the usefulness of the platform in understanding the disease prognosis. Statistical analysis of the obtained SERS spectra using principal component analysis (PCA) showed good agreement with the experimental results, confirming the ability of SERS platform to quantitate HIV-1 viral load and distinguish HIV-1 strains on the basis of their SERS spectra.

Structural, optical, and magnetic properties of Ag+, Mn+ and Ar+ ions implanted ZnO thin films: effect of implantation dose and stopping energy

Herein, we systematically studied the effect of various excitation processes on the structural, optical, and magnetic properties of ZnO films implanted with 80 keV Ar⁺, 110 keV Mn⁺, and 190 keV Ag⁺ ions. Four different doses of 1 × 10¹³, 1 × 10¹⁴, 1 × 10¹⁵, and 2 × 10¹⁶ ions per cm² were used for implantation. It was observed that the structural, optical, and magnetic properties of the implanted samples were dominantly affected at the highest dose of 2 × 10¹⁶ ions per cm². For lower doses, insignificant changes in these properties were observed. A comparison of various processes involved in the implantation process shows that both the electronic excitation and nuclear excitation processes are responsible for the changes in the structural, optical, and magnetic properties of the implanted ZnO films.

Dominant changes in structural, optical, and magnetic properties were observed at the highest dose of implanted ions with larger ionic radii which is due to the large number of produced defects in the host.

Dronedarone versus sotalol in patients with atrial fibrillation: a systematic literature review and network meta-analysis

Background

There are limited comparative data on safety and efficacy within Vaughn Williams class III anti-arrhythmic drugs (AADs) for maintenance of sinus rhythm in adults with atrial fibrillation (AF).

Purpose

We sought to compare the safety and efficacy of dronedarone and sotalol, two commonly prescribed Vaughn Williams class III AADs with class II rate-controlling properties in patients with non-permanent AF.

Methods

A systematic literature review was conducted by searching MEDLINE®, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) up to June 15, 2021. Clinical trials and observational studies that evaluated safety and efficacy of dronedarone or sotalol in adults with AF were included. Where feasible, Bayesian random-effects network meta-analysis (NMA) was conducted to estimate comparative safety and efficacy. Where possible, sensitivity analyses were conducted by including only randomized controlled trials (RCTs).

Results

Of 3,581 records identified through database searches, 37 unique studies (23 RCTs, 13 observational studies, and 1 non-randomized trial) were included in the NMA. Dronedarone was associated with a statistically significantly lower risk of all-cause death versus sotalol in the all-studies NMA (hazard ratio [HR]: 0.38; 95% credible interval [CrI]: 0.19, 0.74; 22 studies); sensitivity analysis followed the same trend numerically (HR: 0.46; 95% CrI: 0.21, 1.02; 16 RCTs). Risk ratios of AF recurrence were not significantly different between dronedarone and sotalol in both all-studies and sensitivity analyses.

Conclusion

Dronedarone, compared with sotalol, was associated with significantly lowered risk of all-cause death in the analysis combining RCTs and observational studies, with no differences in AF recurrence observed between the two therapies. This meta-analysis provides a comprehensive assessment of safety and efficacy evidence useful in evaluating treatment options in AF.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Sanofi

Synchrotron radiation based X-ray techniques for analysis of cathodes in Li rechargeable batteries

Li-ion rechargeable batteries are promising systems for large-scale energy storage solutions. Understanding the electrochemical process in the cathodes of these batteries using suitable techniques is one of the crucial steps for developing them as next-generation energy storage devices. Due to the broad energy range, synchrotron X-ray techniques provide a better option for characterizing the cathodes compared to the conventional laboratory-scale characterization instruments. This work gives an overview of various synchrotron radiation techniques for analyzing cathodes of Li-rechargeable batteries by depicting instrumental details of X-ray diffraction, X-ray absorption spectroscopy, X-ray imaging, and X-ray near-edge fine structure-imaging. Analysis and simulation procedures to get appropriate information of structural order, local electronic/atomic structure, chemical phase mapping and pores in cathodes are discussed by taking examples of various cathode materials. Applications of these synchrotron techniques are also explored to investigate oxidation state, metal-oxygen hybridization, quantitative local atomic structure, Ni oxidation phase and pore distribution in Ni-rich layered oxide cathodes.

Portable fiber-optic SPR platform for the detection of NS1-antigen for dengue diagnosis

Here, we present a portable, selective and cost-effective fiber-optic surface plasmon resonance (SPR) based platform for early detection of Dengue virus. NS1 protein was targeted as the biomarker of dengue. Antibody-antigen specific binding was exploited for NS1 antigen detection. The binding of antibody was assisted by a self-assembled monolayer of alkanethiols on the surface of silver-coated unclad fiber. A wavelength interrogation mode of SPR was utilized to detect NS1 antigen in the dynamic range of 0.2-2.0 μg/ml. The 40 nm thick silver coated optical fiber exhibited resonance wavelength around 500 nm and change in resonance wavelength was monitored for each attachment step on the fiber. The sensitivity at the lowest concentration of NS1 antigen was found to be 54.7 nm/(μg/ml). The limit of detection of the sensor was found to be 0.06 μg/ml, which lies in the physiological range of NS1 protein present in the infected blood, hence the present technique may provide a very early detection advantage. Real blood serum samples were also successfully tested on the set-up, confirming compatibility with the conventional methods. The presented field-deployable platform has wide applications in mass monitoring of dengue, such as during outbreaks and epidemics.

Hierarchically Assembled Cobalt Oxynitride Nanorods and N-Doped Carbon Nanofibers for Efficient Bifunctional Oxygen Electrocatalysis with Exceptional Regenerative Efficiency

Oxygen-based electrocatalysis is an integral aspect of a clean and sustainable energy conversion/storage system. The development of economic bifunctional electrocatalysts with high activity and durability during reversible reactions remains a great challenge. The tailored porous structure and separately presented active sites for oxygen reduction and oxygen evolution reactions (ORR and OER) without mutual interference are most crucial for achieving desired bifunctional catalysts. Here, we report a hybrid composed of sheath-core cobalt oxynitride (CoO_x@CoN_y) nanorods grown perpendicularly on N-doped carbon nanofiber (NCNF). The brush-like CoO_x@CoN_y nanorods, composed of metallic Co₄N cores and oxidized surfaces, exhibit excellent OER activity (E = 1.69 V at 10 mA cm^-2) in an alkaline medium. Although pristine NCNF or CoO_x@CoN_y alone had poor catalytic activity in the ORR, the hybrid showed dramatically enhanced ORR performance (E = 0.78 V at -3 mA cm^-2). The experimental results coupled with a density functional theory (DFT) simulation confirmed that the broad surface area of the CoO_x@CoN_y nanorods with an oxidized skin layer boosts the catalytic OER, while the facile adsorption of ORR intermediates and a rapid interfacial charge transfer occur at the interface between the CoO_x@CoN_y nanorods and the electrically conductive NCNF. Furthermore, it was found that the independent catalytic active sites in the CoO_x@CoN_y/NCNF catalyst are continuously regenerated and sustained without mutual interference during the round-trip ORR/OER, affording stable operation of Zn-air batteries.

Local structure investigation of Co-Fe-Si-B ribbons by extended X-ray absorption fine-structure spectroscopy

In the present work, extended X-ray absorption fine-structure (EXAFS) investigations of Co₆₉Fe_xSi_21-xB₁₀ (x = 3, 5, 7) glassy ribbons were performed at the Co K-edge. The magnitude of the first peak of the Fourier transforms of the EXAFS signals is found to increase monotonically with increasing Si concentrations indicating the formation of the localized ordered structure at the atomic scale. The Co-Si coordination number (CN) increases at the expense of the CN of Co/Fe. Smaller interatomic distances are observed in the glassy phase compared with that in the crystalline phase which promotes the stability of the glassy phase. Calculations of the thermodynamic parameter (P_HSS), cohesive energy (E_C) and the atomic radius difference (δ) parameter show that the alloy composition Co₆₉Fe₃Si₁₈B₁₀ has a good glass-forming ability (GFA) with the highest CN of Si compared with other compositions. A linear correlation of CN with that of the GFA parameter (P_HSS) exists and the CN also plays a crucial role in the GFA of the glassy alloys. This parameter should be considered in developing different GFA criteria.

MgO Thin Film Growth on Si(001) by Radio-Frequency Sputtering Method

Herein, sputtering duration and annealing temperature effects on the structure and local electronic structure of MgO thin films were studied using synchrotron radiation based X-ray diffraction and X-ray absorption spectroscopic investigations. These films were grown at substrate temperature of 350 °C by varying sputtering duration from 25 min to 324 min in radio frequency (RF) sputtering method followed by post-deposition annealing at 400, 600 and 700 °C for 3 h. These films were amorphous upto certain sputtering durations, typically upto 144 min and attains crystallization thereafter. This kind of behavior was observed at all annealing temperature. The textured coefficient of crystalline films envisaged that the orientation was affected by annealing temperature. Coordination of Mg²⁺ ions was more distorted in amorphous films compared to crystalline films. Moreover, onset of molecular oxygen are absorbed at low annealing temperature on these films.

Portable and sensitive Ag nanorods based SERS platform for rapid HIV-1 detection and tropism determination

In this study, surface-enhanced Raman scattering (SERS) based field-deployable platform has been explored for early detection and distinction of the human immunodeficiency virus (HIV-1). A highly optimized silver nanorods array, fabricated using glancing angle deposition technique was used as SERS substrate. Distinct signature peaks for varying concentrations (10² to 10⁶ copies/mL) were identified in five different HIV-1 subtypes (A, B, C, D, and CRF02_AG). Binding of viruses directly with Ag nanorods without using antibodies or intermediate reagents is shown. The purified viruses were spiked in water and healthy plasma to capture pure HIV-1 peaks. Distinct peaks were also captured for the X4 and R5 tropic strains suggesting tropism based detection. The above data was further confirmed and analyzed statistically using a multivariate tool. Thus, the present study indicates the ability of the SERS platform to detect and differentiate the HIV-1 virus implying its further validation using clinical specimens and isolates.

Local Electronic Structure of Calcite Investigated Using X-ray Absorption Spectroscopy at Different Span of Time

For the present work, calcite nanoparticles was synthesized from calcium nitrate by annealing precursor at 300, 400, 500 and 600°C. Ca K-edge near edge X-ray absorption fine structure measurements revealed spectral features characteristics to the amorphous phase of calcium carbonate at 300 and 400°C. At 500 and 600°C, the spectra were analogues to the calcite phase of calcium carbonate. Simulation of extended X-ray absorption fine structure spectra envisaged that both coordination number and bond distance for Ca-O bonds decreased with annealing temperature. Both parameters attained values close to standard calcite when annealed at 600°C. The spectral features at Ca L-, O K- and C K-edge near edge X-ray absorption fine structure appeared at same positions for different ages, which envisaged the occurrence of almost same local electronic structure for different span of times.

Approaches to synthesize MgO nanostructures for diverse applications

Magnesium oxide remained interesting from long time for several important phenomena like; defect induced magnetism, spin electron reflectivity, broad laser emission etc. Moreover, nanostructures of this material exhibited suitability for different kinds of applications ranging from wastewater treatment to spintronics depending upon their shape and size. In this way, researchers had grown nanostructures in the form of nanoparticles, thin films, nanotubes, nanowalls, nanobelts. Though nanoparticles and thin films are well known form of nanostructures and wide variety of synthesis approaches are available, however, limited methodology for other nanostructures are available. In order to grow these nanostructures in an optimized way an understanding of these methods is essential. Thus, this review article depicts an overview of various approaches for design of different kinds of nanostructures.

Correlating the size and cation inversion factor in context of magnetic and optical behavior of CoFe2O4 nanoparticles

Herein, the size dependent behavior of cobalt ferrite nanoparticles was investigated using synchrotron radiation based techniques. Scanning electron micrographs revealed the enhancement of particle/crystallite size with increase of annealing temperature. Moreover, the shape of these particles also changed with increase of crystallite size. Saturation magnetization increased with increase of crystallite size. The higher saturation magnetization for larger crystallite size nanoparticles was attributed to a cation distribution similar to that of bulk CoFe2O4. The optical band-gap of these nanoparticles decreased from 1.9 eV to 1.7 eV with increase of crystallite size. The enhancement of the optical band-gap for smaller crystallites was due to phenomena of optical confinement occurring in the nanoparticles. Fe L Co L-edge near edge extended X-ray absorption fine structure (NEXAFS) measurements showed that Fe and Co ions remain in the 3+ and 2+ state in these nanoparticles. The results obtained from Fe & Co K-edge X-ray absorption near edge structure (XANES)-imaging experiments further revealed that this oxidation state was possessed by even the crystallites. Extended X-ray absorption fine structure (EXAFS) measurements revealed distribution of Fe and Co ions among tetrahedral (A) and octahedral (B) sites of the spinel structure which corroborates the results obtained from Rietveld refinement of X-ray diffraction patterns (XRD). X-ray magnetic circular di-chroism (XMCD) measurements revealed negative exchange interaction among the ions situated in tetrahedral (A) and octahedral (B) sites. Theoretical and experimental calculated magnetic moments revealed the dominancy of size effects rather than the cation redistribution in the spinel lattice of CoFe2O4 nanoparticles.

Soft X-ray Absorption Spectroscopic Investigation of Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials

Herein, we report the soft X-ray absorption spectroscopic investigation for Li(Ni0.8Co0.1Mn0.1)O2 cathode material during charging and discharging. These measurements were carried out at the Mn L-, Co L-, and Ni L-edges during various stages of charging and discharging. Both the Mn and Co L-edge spectroscopic measurements reflect the invariance in the oxidation states of Mn and Co ions. The Ni L-edge measurements show the modification of the oxidation state of Ni ions during the charging and discharging process. These studies show that eg states are affected dominantly in the case of Ni ions during the charging and discharging process. The O K-edge measurements reflect modulation of metal-oxygen hybridization as envisaged from the area-ratio variation of spectral features corresponding to t2g and eg states.

Development of XANES nanoscopy on BL7C at PLS-II

X-ray absorption near-edge structure (XANES) imaging is a powerful tool to visualize the chemical state distribution of transition-metal-based materials at synchrotron radiation facilities. In recent years, the electrochemical working rechargeable battery has been the most studied material in XANES imaging owing to the large increase of portable electronics and electric vehicles. This work acknowledges the importance of battery analysis and has developed the XANES imaging system on BL7C at Pohang Light Source-II (PLS-II). BL7C employs an undulator taper configuration to obtain an energy band >130 eV near the K-absorption edge of the target element with a minimum energy interval >0.2 eV. While measuring energy-dependent images, the zone plate translation maintains the best focus, and then various data processes such as background correction, image registration and clustering allow single XANES spectrum extraction and chemical distribution mapping. Here, the XANES imaging process is described, the XANES spectrum quality is identified and the chemical states of the partially charged cathode material used in lithium-ion batteries as an application example are examined.

SERS Platform for Dengue Diagnosis from Clinical Samples Employing a Hand Held Raman Spectrometer

Dengue is a serious global health concern especially in tropical and subtropical countries. About 2.5 billion of the world's population is at risk for dengue infection. Early diagnosis is the key to prevent the deterioration of health of the patient to severe illness. Laboratory diagnosis of dengue is essential for providing appropriate supportive treatment to dengue patients with febrile illness, which is difficult to diagnose clinically. Here, we demonstrate surface enhanced Raman scattering (SERS) based diagnosis of dengue virus in clinical blood samples collected from total of 102 subjects. All of the samples were well characterized by conventional NS1 antigen and IgM antibody ELISA kits. The silver nanorods array fabricated by glancing angle deposition technique were employed as SERS substrates. A small amount of patient blood serum (5 μL) was taken for analysis and the report was prepared within a minute. SERS spectra of pure NS1 protein as well as spiked in serum was also recorded separately. Principal component analysis (PCA) was employed as the statistical tool to differentiate dengue positive, dengue negative, and healthy subjects on the basis of their respective SERS spectra. This method provides a sensitive, rapid, and field deployable diagnosis of dengue at the early stage (within 5 days of the onset of symptoms).

P5684Left ventricular wall thickness measured with computed tomography stratifies the response to cardiac resynchronization therapy in patients with non-ischemic cardiomyopathy

Background

Cardiac resynchronization therapy (CRT) has provided benefit in selected heart failure (HF) patients. Unfortunately, up to 30% of device recipients do not benefit clinically from CRT. Left ventricular (LV) wall geometry analyzed using computed tomography (CT) has not been evaluated in the response to CRT. The objective of this study was to examine the association of LV wall thickness (WT) and the ability for reverse LV remodeling after CRT in non ischemic cardiomyopathy (NICM) patients.

Methods

In this prospective study, a total 54 patients (33 NICM) scheduled for CRT, underwent pre procedural CT. Reduced LV WT was defined as WT≤6mm and was quantified as a percentage of total LV area. End points were 6-month clinical and echocardiographic response to CRT (NYHA functional class, LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVEDV)) and 2-year major adverse cardiac events (MACE). Of note, positive reduction was defined as in reduction LVESV and LVEDV by ≥15% and ≥10% respectively and ≥5% absolute increase in LVEF.

Results

The 33 NICM enrolled patients were divided in 3 groups according to the percentage of LV WT<6mm area: ≤20% (low LV WT area); 20–50% (moderate LV WT area) and ≥50% (high LV WT area). At 6 months, 78%, 67% and 25% of the patients experienced NYHA class improvement by ≥1 in the ≤20%, 20–50% and ≥50% group respectively. Furthermore, majority of patients in the ≤20% and 20–50% groups (92% and 75% respectively) had a significant improvement of their global assessment compared to only 38% in the ≥50% group. Additionally, low LV WT area group presented a significant LVEF, LVEDV and LVESV positive response rate (92%, 69% and 85% respectively). Patients included in the moderate and high groups exhibited gradually lower LVEF, LVEDV and LVESV positive response rate (42% and 50%; 67% and 50%; 75% and 50%, respectively). Notably, patients with the least LV WT (i.e ≥50% group) experienced significantly lower 2-years MACE survival free probability than other groups.

Left ventriculat segmentation

Conclusion

LV WT evaluated using CT could help to stratify the response to CRT in NICM patients.

P3804Left ventricular wall thickness measured with computed tomography predicts mitral regurgitation improvement in patients implanted with cardiac resynchronization therapy

Background

Secondary mitral regurgitation (MR) is common in heart failure (HF) patients and results in progressive left ventricular (LV) dilatation, papillary muscle (PM) displacement and mitral valve leaflet tethering. In selected HF patients, cardiac resynchronization therapy (CRT) has been proved to reduce MR by LV reverse remodeling, resynchronization of PM insertion site contraction and reduction in MV tenting area and inter PM distance. However, data regarding the impact of LV wall thickness (WT) on MR improvement are scarce.

Methods

In this prospective study, a total 54 patients scheduled for CRT, underwent pre procedural CT. Reduced LV WT was defined as WT<6mm and was quantified as a percentage of total LV area. LV was segmented in 17 segments to assess the number of LV segments with reduced WT. End point was 6-month echocardiographic MR improvement by ≥1 class. For this analysis, we focused on patient with mild (class 2) to severe (class 4) MR.

Results

Among the 54 patients, 38 (70.4%) had mild to severe MR at baseline and a total of 16 (42.1%) experienced MR improvement by ≥1 class at 6 months. there was no difference regarding the co-morbidities, electrocardiogram and echocardiographic parameters between patients with or without MR improvement. However, patients without MR improvement had significant higher NT-pro BNP level at baseline. Interestingly, patients without MR improvement had larger LVWT <6mm area (41.541.5±19.4 vs. 22.4±16.1%, p=0.003) associated with higher number of papillary muscle (PM) inserted in reduced LV WT area. In multivariate analysis, an area ≥25% of LVWT<6mm including at least 1 PM insertion was the only predictor of no MR improvement at 6 months (HR 18.4 (1.25–271.75), p=0.034). Lastly, patients with MR improvement had significant lower rate of basal segments with reduced WT, especially in the lateral location. Of note, patients with MR improvement exhibited fewer rate of postero-lateral WT <6mm segments.

Left ventriculat segmentation

Conclusion

LV WT evaluated using CT is a strong predictor of no MR improvement in HF patients with mild to severe MR and who scheduled for CRT implantation.

Electrochemical water oxidation by simple manganese salts

Recently, it has been great efforts to synthesize an efficient water-oxidizing catalyst. However, to find the true catalyst in the harsh conditions of the water-oxidation reaction is an open area in science. Herein, we showed that corrosion of some simple manganese salts, MnCO3, MnWO4, Mn3(PO4)2 · 3H2O, and Mn(VO3)2 · xH2O, under the water-electrolysis conditions at pH = 6.3, gives an amorphous manganese oxide. This conversion was studied with X-ray absorption spectroscopy (XAS), as well as, scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), spectroelectrochemistry and electrochemistry methods. When using as a water-oxidizing catalyst, such results are important to display that long-term water oxidation can change the nature of the manganese salts.

A trimetallic organometallic precursor for efficient water oxidation

Herein, we report an iron/nickel/zinc mixed oxide as a catalyst for the electrochemical water oxidation. This catalyst was synthesized by a straightforward method for the synthesis of an iron/nickel/zinc mixed oxide through the calcination of a Fe/Ni/Zn organometallic compound. The calcined product contains Fe and Ni as crucial ions for water oxidation, accompanied by the presence of Zn ions. The removal of Zn ions from the mixed oxide provides more active sites on the surface of the catalyst. The composition of the compound was characterized by some common methods and found to be an efficient water-oxidizing catalyst. The catalyst on FTO at pH = 13 yields a current density of 12 mA/cm² at 1.2 V (vs. Ag│AgCl). After 5 hours at 1.1 V, the electrode not only shows no decrease in performance, but also shows an increase from 4 to 7 mA/cm² in the water oxidation activity. Tafel plot, for the electrode at pH = 13 in KOH solution (0.1 M) showed linearity for the graph of lg j vs. V with both relatively low (220.4 mV per decade) and high overpotentials (903.7 mV per decade).

Nanosized (Ni1-x Zn x )Fe2O4 for water oxidation

Performing water splitting for H₂ production is an interesting method to store different energies. For water splitting, an efficient and stable water-oxidizing catalyst is important. Ni-Fe (hydr)oxides are among the best catalysts for water oxidation in alkaline electrolytes. An Fe amount higher than 50% in Ni-Fe (hydr)oxides increases the overpotential for water oxidation. Thus, Ni-Fe (hydr)oxides with a high ratio of Fe to Ni have rarely been focused on for water oxidation. Herein, we report water oxidation using nanosized (Ni_1-x Zn _x )Fe₂O₄. The catalyst was characterized via some methods and tested at pH values of 3, 7 and 11 in phosphate buffer. Nanosized (Ni_1-x Zn _x )Fe₂O₄ is a good catalyst for water oxidation only under alkaline conditions. In the next step, amperometry studies showed current densities of 3.50 mA cm^-2 and 11.50 mA cm^-2 at 1.25 V in 0.10 M and 1.0 M KOH solution, respectively. The amperometric measurements indicated high catalyst stability in both 0.10 M and 1.0 M KOH. Tafel plots were obtained in KOH solution at concentrations of both 0.10 M and 1.0 M. At pH = 13 in KOH solution (0.10 M), linearity of lg(j) vs. potential was shown, with two slopes relating to both relatively low (170.9 mV per decade) and high overpotentials (484.2 mV per decade). In 1.0 M KOH solution, the Tafel plot showed linearity of lg(j) vs. potential, with two slopes relating to both relatively low (192.5 mV per decade) and high overpotentials (545.7 mV per decade). After water oxidation, no significant change was observed in the catalyst.

A nickel(ii) complex under water-oxidation reaction: what is the true catalyst?

A Ni(ii) complex as a water-oxidizing catalyst under electrochemical conditions was studied and the role of Ni oxide as a true catalyst was investigated.

A manganese(ii) phthalocyanine under water-oxidation reaction: new findings

The decomposition reaction for a manganese complex under water oxidation was investigated.

Photomechanical and Chemomechanical Actuation Behavior of Graphene-Poly(dimethylsiloxane)/Gold Bilayer Tube for Multimode Soft Grippers and Volatile Organic Compounds Detection Applications

Graphene polymers-based soft actuators driven by infrared (IR) light have attracted wide attention recently. However, the scientific fraternity is striving hard in unraveling the area of actuators that could be triggered by IR light along with chemicals. The fabricating methodology of multiresponsive soft actuators based on graphene nanoplatelets (GNPs)-poly(dimethylsiloxane) (PDMS) nanocomposite/gold bilayers, ensuring large, fast, and reversible response, has been illustrated. The actuators display a novel dual-mode operation as photomechanical and chemomechanical actuation. The actuators are realized by depositing a thin film (100 nm) of gold on GNP-PDMS nanocomposite films resulting tubular structure on account of thermal residual stress. The actuation response of this structure upon its exposure to IR light and chemicals was measured in terms of percentage opening and degree of unscroll, respectively. The three-dimensional tubular structure is transformed into a two-dimensional sheet within 8 s under IR light irradiation. The same structures were also tested in various organic solvents like methanol, ethanol, acetone, isopropyl alcohol, and aldehydes, but the actuation has been observed only in acetone and aldehydes. This tubular actuator unscrolls completely and then scrolls in opposite direction along with tube axis shift through 90° during its exposure to acetone (liquid/vapors) and aldehydes. Few applications of these actuators, such as multimode soft grippers for on-demand capture/release of objects (with weight 1.2 times the actuator's own weight) and volatile organic compounds detection module, have been demonstrated. The combination of surface micromachining techniques of microelectromechanical systems process with this smart material may find applications in drug-delivery systems with precise control, soft robotics, and noninvasive diagnosis of diabetes and breast/lung cancers.

Microstructure, local electronic structure and optical behaviour of zinc ferrite thin films on glass substrate

Zinc ferrite thin films were deposited using a radio-frequency-sputtering method on glass substrates. As-deposited films were annealed at 200°C for 1, 3 and 5 h, respectively. X-ray diffraction studies revealed the amorphous nature of as-grown and annealed films. Thickness of as-deposited film is 96 nm as determined from Rutherford backscattering spectroscopy which remains almost invariant with annealing. Transmission electron microscopic investigations envisaged a low degree of crystalline order in as-deposited and annealed films. Thicknesses estimated from these measurements were almost 62 nm. Roughness values of these films were almost 1-2 nm as determined from atomic force microscopy. X-ray reflectivity measurements further support the results obtained from TEM and AFM. Near-edge X-ray absorption fine structure measurements envisaged 3+ and 2+ valence states of Fe and Zn ions in these films. UV-Vis spectra of these films were characterized by a sharp absorption in the UV region. All films exhibited almost the same value of optical band gap within experimental error, which is close to 2.86 eV.

Atomic-scale investigation of MgO growth on fused quartz using angle-dependent NEXAFS measurements

The phenomena related to thin film growth have always been interesting to the scientific community. Experiments related to these phenomena not only provide an understanding but also suggest a path for the controlled growth of these films. For the present work, MgO thin film growth on fused quartz was investigated using angle-dependent near-edge X-ray absorption fine structure (NEXAFS) measurements. To understand the growth of MgO, sputtering was allowed for 5, 10, 25, 36, 49, 81, 144, 256, and 400 min in a vacuum better than 5.0 × 10⁻⁷ torr. NEXAFS measurements revealed the evolution of MgO at the surface of fused quartz for sputtering durations of 144, 256, and 400 min. Below these sputtering durations, no MgO was observed. NEXAFS measurements further envisaged a systematic improvement of Mg²⁺ ion coordination in the MgO lattice with the sputtering duration. The onset of non-interacting molecular oxygen on the surface of the sputtered species on fused quartz was also observed for sputtering duration up to 81 min. Angle-dependent measurements exhibited the onset of an anisotropic nature of the formed chemical bonds with sputtering, which dominated for higher sputtering duration. X-ray diffraction (XRD) studies carried out for sputtering durations of 144, 256, and 400 min exhibited the presence of the rocksalt phase of MgO. Annealing at 700 °C led to the dominant local electronic structure and improved the crystallinity of MgO. Rutherford backscattering spectrometry (RBS) and cross-sectional scanning electron microscopy (SEM) revealed a layer of almost 80 nm was obtained for a sputtering duration of 400 min. Thus, these angle-dependent NEXAFS measurements along with XRD, RBS, and SEM analyses were able to give a complete account for the growth of the thin films. Moreover, information specific to the coordination of the ions, which is important in case of ultrathin films, could be obtained successfully using this technique.

Near edge X-ray absorption fine structure measurements reveal the formation of MgO on fused quartz substrate.

Uptake, Distribution, and Transformation of Zerovalent Iron Nanoparticles in the Edible Plant Cucumis sativus

Here, we investigated the fate of nanoscale zerovalent iron (nZVI) on the Cucumis sativus under both hydroponic and soil conditions. Seedlings were exposed to 0, 250, and 1000 mg/L (or mg/kg soil) nZVI during 6-9 weeks of a growth period. Ionic controls were prepared using Fe-EDTA. None of the nZVI treatments affected the plant biomass. On the basis of the total iron contents and the superparamagnetic property of nZVI-exposed roots, there was no evidence of pristine nZVI translocation from the roots to shoots. Electron microscopy revealed that the transformed iron nanoparticles are stored in the root cell membrane and the vacuoles of the leaf parenchymal cells. X-ray absorption spectroscopy identified ferric citrate (41%) and iron (oxyhydr)oxides (59%) as the main transformed products in the roots. The shoot samples indicated a larger proportion of ferric citrate (60%) compared to iron (oxyhydr)oxides (40%). The 1.8-fold higher expression of the CsHA1 gene indicated that the plant-promoted transformation of nZVI was driven by protons released from the root layers. The current data provide a basis for two potential nZVI transformation pathways in Cucumis sativus: (1) interaction with low molecular weight organic acid ligands and (2) dissolution-precipitation of the mineral products.

Sunlight-driven eco-friendly smart curtain based on infrared responsive graphene oxide-polymer photoactuators

Photomechanical actuation is the conversion of light energy into mechanical energy through some smart materials. Infrared-responsive smart materials have become an emerging field of research due to easy availability and eco-friendly nature of their stimulus in the form of sunlight, which contains about 50% of near-infrared(nIR) making these materials useful at macro-scale photoactuator applications. Here, we demonstrate fabrication of highly versatile nIR triggered photoactuators based on graphene oxide/polycarbonate bilayers that offers fast, low-cost fabrication, large deflection, reversible actuation and wavelength-selective response. The photoactuators are realized by vacuum filtration of graphene oxide/water dispersion through polycarbonate membrane resulting graphene oxide/polymer bilayer structure. The photoactuation response was measured in the form of deflection from equilibrium position as a result of infrared-irradiation. The deflection is caused by the generated thermal stress at the interface of bilayers due to mismatch of thermal expansion coefficient as a results of nIR absorption by graphene oxide and subsequent temperature rise. A maximum deflection of 12 mm (circular-shaped structure with diameter 28 mm) with corresponding bending curvature of 0.33 cm-1 was shown by this photoactuator for illumination intensity of 106 mW/cm2. Few applications of these photoactuators such as sunlight-driven smart curtain, infrared actuated curtain and self-folding box are also demonstrated.

Water oxidation by simple manganese salts in the presence of cerium(iv) ammonium nitrate: towards a complete picture

For the first time, using some methods, we showed that under the water-oxidation conditions and in the presence of cerium(iv) ammonium nitrate, some manganese salts are converted to Mn oxide.

Mechanistic insights into the interaction between energetic oxygen ions and nanosized ZnFe2O4: XAS-XMCD investigations

Irradiation of nanosized zinc ferrite with swift heavy ions leads to cation redistribution and changes in magnetic interactions.

The application of a nickel(ii) Schiff base complex in water oxidation: the importance of nanosized materials

The role of Ni oxide in the electrocatalytic water oxidation of a nickel(ii) Schiff base (N,N′-bis (salicylidene) ethylenediamino nickel(ii)) is investigated.

Links between peptides and Mn oxide: nano-sized manganese oxide embedded in a peptide matrix

We report on a poly-peptide/Mn oxide nanocomposite as a model for the water-oxidizing catalyst in Photosystem II.

An alternative approach for estimating above ground biomass using Resourcesat-2 satellite data and artificial neural network in Bundelkhand region of India

Determination of above ground biomass (AGB) of any forest is a longstanding scientific endeavor, which helps to estimate net primary productivity, carbon stock and other biophysical parameters of that forest. With advancement of geospatial technology in last few decades, AGB estimation now can be done using space-borne and airborne remotely sensed data. It is a well-established, time saving and cost effective technique with high precision and is frequently applied by the scientific community. It involves development of allometric equations based on correlations of ground-based forest biomass measurements with vegetation indices derived from remotely sensed data. However, selection of the best-fit and explanatory models of biomass estimation often becomes a difficult proposition with respect to the image data resolution (spatial and spectral) as well as the sensor platform position in space. Using Resourcesat-2 satellite data and Normalized Difference Vegetation Index (NDVI), this pilot scale study compared traditional linear and nonlinear models with an artificial intelligence-based non-parametric technique, i.e. artificial neural network (ANN) for formulation of the best-fit model to determine AGB of forest of the Bundelkhand region of India. The results confirmed the superiority of ANN over other models in terms of several statistical significance and reliability assessment measures. Accordingly, this study proposed the use of ANN instead of traditional models for determination of AGB and other bio-physical parameters of any dry deciduous forest of tropical sub-humid or semi-arid area. In addition, large numbers of sampling sites with different quadrant sizes for trees, shrubs, and herbs as well as application of LiDAR data as predictor variable were recommended for very high precision modelling in ANN for a large scale study.

Role of silver doping on the defects related photoluminescence and antibacterial behaviour of zinc oxide nanoparticles

The Ag doped ZnO (ZnO:Ag) NPs with a hexagonal wurtzite structure were synthesized by a solution combustion method. X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopy (XPS) were used to study the defects, local electronic and atomic structures before and after Ag doping. XPS and XANES studies confirmed the deficiency of concentration of defects in ZnO after Ag doping. The photoluminescence study showed the deep level emission in the orange-red region in addition to the band to band emission. It was also found that the defect related emission of ZnO was decreased with an increasing in Ag concentration. The antibacterial behaviour of ZnO and ZnO:Ag NPs was studied against the gram positive and gram negative bacteria. The role of Ag doping and defects in the ZnO NPs were discussed for the observed antibacterial and photoluminescence behaviour.

Tunichrome-Inspired Gold-Enrichment Dispersion Matrix and Its Application in Water Treatment: A Proof-of-Concept Investigation

Tunicate, a filter-feeder in seawater, is able to accumulate high amount of metals using intracellular polymer matrices. The woven pyrogallol structures of tunichrome, a small peptide contained in tunicate's blood cells, is believed to be responsible for selective metal sequestration in tunicates from seawater. However, the intriguing tunichrome matrix is difficult both to harvest from the tunicate and to synthesize massively due to the extreme oxidation sensitivity of the pyrogallol moiety which limits the study scope. Here, we succeeded to mimic tunichrome by conjugating two cheap and naturally occurring components: pyrogallol-5-carboxylic acid (gallic acid) and chitin nanofiber. A tunicate-mimetic infiltration matrix of surface-tailored chitin nanofibers with pyrogallol moieties (CGa) demonstrated the versatility of this strategy in generation of ingenious filtration material, especially for unprecedented fine and clean gold recovery inside of the tunicate-mimetic infiltration matrix (>99%, 533 mg gold per gram weight), which exceeds that of the presently most popular materials. Complexation between pyrogallol on the nanofiber and gold was similar to that of a tunichrome's metal sequestration. Extended X-ray absorption fine structure (EXAFS) spectroscopy and data-fitting elucidated the decreased coordination numbers for Au-Au nearest neighbors, demonstrating that gold coordinated to pyrogallol units, followed by an intramolecular association of Au⁰. A catalytic reduction of 4-nitrophenol mediated by the tunicate-mimetic matrix with harvested gold revealed excellent recyclability up to 30 cycles (∼95% reduction), which together with methylene blue reduction and antimicrobial performances indicates the versatile characteristics of sustainable processes by the tunichrome mimetics. This strategy opens the door for fast-developing new biomimetic alternatives for precious metal recovery, which is not restricted to gold and can offer a tool for multifaceted soft/hard nanomaterials.

ZnO-Nanowires-Coated Smart Surface Mesh with Reversible Wettability for Efficient On-Demand Oil/Water Separation

The rapid industrial growth has led to the large production of oily wastewater. Treatment of oily wastewater is an inevitable challenge to manage the greater demand of clean water for the rapidly growing population and economy. In the present work, we have developed a smart surface mesh with reversible wetting properties via a simple, ecofriendly, and scalable approach for on-demand oil-water separation. ZnO nanowires (NWs) obtained from the chemical vapor deposition method were coated on a stainless steel (SS) mesh. The as-synthesized ZnO-NWs-coated mesh shows superhydrophilic/underwater superoleophobic behavior. This mesh works in "water-removing" mode, where the superhydrophilic as well as underwater superoleophobic nature allows the water to permeate easily through the mesh while preventing oil. The wetting property of ZnO-NWs-coated mesh can be switched easily from superhydrophilic to superhydrophobic state and vice versa by simply annealing it at 300 °C alternatively under hydrogen and oxygen environment. The separation is solely driven by gravity. Thus, the reversible wettability of ZnO NWs provides a smart surface mesh which can be switched between "oil-removing" and "water-removing" modes. It was found that for more than 10 cycles of mesh reutilization in both modes alternatively, the separation efficiency of 99.9% stayed relatively invariant, indicating a prolonged antifouling property and excellent recyclability. This work provides a simple, fast, cost-effective, and on-demand solution for oily wastewater treatment and opens up new perspectives in the field of controllable oil-water separation.

Antimicrobial Properties of Teas and Their Extracts in vitro

Tea has recently received the attention of pharmaceutical and scientific communities due to the plethora of natural therapeutic compounds. As a result, numerous researches have been published in a bid to validate their biological activity. Moreover, major attention has been drawn to antimicrobial activities of tea. Being rich in phenolic compounds, tea has the preventive potential for colon, esophageal, and lung cancers, as well as urinary infections and dental caries, among others. The venture of this review was to illustrate the emerging findings on the antimicrobial properties of different teas and tea extracts, which have been obtained from several in vitro studies investigating the effects of these extracts against different microorganisms. Resistance to antimicrobial agents has become an increasingly important and urgent global problem. The extracts of tea origin as antimicrobial agents with new mechanisms of resistance would serve an alternative way of antimicrobial chemotherapy targeting the inhibition of microbial growth and the spread of antibiotic resistance with potential use in pharmaceutical, cosmetic, and food industries.

Nanosized manganese oxide/holmium oxide: a new composite for water oxidation

Ho₂O₃ as a support for nanosized Mn oxide was used for the synthesis of a new water-oxidizing catalyst.

Mechanistic insights on the electronic properties and electronic/atomic structure aspects in orthorhombic SrVO3 thin films: XANES–EXAFS study

Distortion in the V–O6 octahedra is observed in SrVO₃ thin films and leads to larder separation between bonding and anti-bonding d_‖ orbitals.

A new strategy to make an artificial enzyme: photosystem II around nanosized manganese oxide

A new strategy to make an artificial enzyme was reported.

Utilization of services for institutional deliveries in Gorkha District

BACKGROUND

Adequate health services for improving maternal and neonatal health is an important global health issues. Institutional delivery is most important component to address maternal and neonatal issue. Institutional delivery service utilization assures safe birth and minimizes the maternal morbidity and mortality. This study was aimed to assess the utilization of institutional delivery service among the mothers of Gorkha district.

METHODS

A cross sectional study of 180 mothers having child below 2 years residing in Palungtar municipality was done between March to July 2015. Information was collected by using an interviewer administered semi-structured questionnaire. Chi-square test was used to for data analysis.

RESULTS

Of total, 93.3% of the mother gave birth to their current child at health institution. The study variables like age at marriage, knowledge on delivery incentive, long waiting hours at health facility, Information on maternal health before current pregnancy, age at first pregnancy, gestational age at first ANC visit and women knowing differences between home and institutional delivery were independent factors influencing utilization of institutional delivery service.

CONCLUSIONS

Promotion of information, education and communication on maternal health services and delivery incentives could result in utilization of institutional delivery services.

Contributors to Enhanced CO2 Electroreduction Activity and Stability in a Nanostructured Au Electrocatalyst

The formation of a nanostructure is a popular strategy for catalyst applications because it can generate new surfaces that can significantly improve the catalytic activity and durability of the catalysts. However, the increase in the surface area resulting from nanostructuring does not fully explain the substantial improvement in the catalytic properties of the CO2 electroreduction reaction, and the underlying mechanisms have not yet been fully understood. Here, based on a combination of extended X-ray absorption fine structure analysis, X-ray photoelectron spectroscopy, and Kelvin probe force microscopy, we observed a contracted Au-Au bond length and low work function with the nanostructured Au surface that had enhanced catalytic activity for electrochemical CO2 reduction. The results may improve the understanding of the enhanced stability of the nanostructured Au electrode based on the resistance of cation adhesion during the CO2 reduction reaction.