Investigation of Dielectric, Ferroelectric, and Strain Responses of (1 - x)[0.90(Bi0.5Na0.5)TiO3 - 0.10SrTiO3] - xCuO Ceramics.

The low-temperature sintering of (Bi0.5Na0.5)TiO3-based ceramics can be achieved by sintering aid CuO. Piezoelectric ceramics (1 - x)[0.90(Bi0.5Na0.5)TiO3 - 0.10SrTiO3] - xCuO (BNT-ST-Cu) with x = 0, 0.01, 0.02, 0.03, and 0.04 were prepared through the mixed oxide route. A tetragonal structure was indexed for the undoped sample. Its structure was found to be changed to a pseudocubic when Cu was added. For undoped Cu samples, the sintering temperature (T s) for sufficient densification was 1160 °C. However, T s was reduced to 1090-1120 °C for Cu-added specimens. Field emission scanning electron microscopy (FE-SEM) showed a uniform and dense grain morphology for all samples. The maximum dielectric constant temperature (T m) was decreased with the doping concentration of Cu and applied frequency. The strain was increased with Cu concentration and had the maximum value of 500 pm/V for the sample x = 0.02 with symmetric and slim strain loops.

Effect of soil texture and zinc oxide nanoparticles on growth and accumulation of cadmium by wheat: a life cycle study.

Cadmium (Cd) is getting worldwide attention due to its continuous accumulation in agricultural soils which is due to anthropogenic activities and finally Cd enters in food chain mainly through edible plants. Cadmium free food production on contaminated soils is great challenge which requires some innovative measures for crop production on such soils. The current study evaluated the efficiency of zinc oxide nanoparticles (ZnONPs) (0, 150 and 300 mg/kg) on the growth of wheat in texturally different soils including clay loam (CL), sandy clay loam (SCL), and sandy loam (SL) which were contaminated with were contaminated with 25 mg/kg of Cd before crop growth. Results depicted that doses of ZnONPs and soil textures significantly affected the biological yields, Zn and Cd uptake in wheat plants. The application of 300 mg/kg ZnONPs caused maximum increase in dry weights of shoot (66.6%), roots (58.5%), husk (137.8%) and grains (137.8%) in CL soil. The AB-DTPA extractable Zn was increased while Cd was decreased with doses of NPs depending upon soil textures. The maximum decrease in AB-DTPA extractable Cd was recorded in 300 mg/kg of ZnONPs treatment which was 58.7% in CL, 33.2% in SCL and 12.1% in SL soil as compared to respective controls. Minimum Cd concentrations in roots, shoots, husk and grain were found in 300 mg/kg ZnONPs amended CL soil which was 58%, 76.7%, 58%, and 82.6%, respectively. The minimum bioaccumulation factor (0.14), translocation index (2.46) and health risk index (0.05) was found in CL soil with the highest dose of NPs. The results concluded that use of ZnONPs significantly decreased Cd concentration while increased Zn concentrations in plants depending upon doses of NPs and soil textures.

Antimicrobial therapy, resistance, and appropriateness in healthcare-associated and community-associated infections; a point prevalence survey.

BACKGROUND: Data examining differences in antimicrobial therapy and its appropriateness between healthcare-associated infections (HAIs) and community-associated infections (CAIs) are limited. The objective was to compare antimicrobial therapy, resistance, and appropriateness between CAIs and HAIs. METHODS: One-day point prevalence survey targeting admitted patients with active infections was conducted in six tertiary care hospitals. Antimicrobial appropriateness was decided based on hospital antimicrobial guidelines, clinical assessment, culture results, and other relevant investigations. RESULTS: Out of 1666 patient records reviewed, 240 (14.4%) infection events were identified. Prevalence of infections treated with antimicrobials were 6.5% for HAIs and 7.1% for CAIs. The most commonly prescribed antimicrobials were carbapenems (19.6%), cephalosporins (14.8%), and vancomycin (13.2%), with some differences between HAIs and CAIs. The overall contribution of MDR pathogens to both HAIs and CAIs was similar (34.0% versus 34.3%, p = 0.969). ESBL was significantly associated with CAIs while other gram-negative MDR pathogens significantly associated with HAIs. Overall appropriateness of antimicrobial therapy was similar in HAI and CAI events (64.2% versus 64.7%, p = 0.934). However, it was highest in aminoglycosides (78.6%) and lowest in vancomycin (40.8%). It was lowest in bloodstream infections than other infections (48.5% versus 61% to 78%, p = 0.044). CONCLUSION: Although the overall burden of MDR pathogens and appropriateness of antimicrobial therapy were similar in HAI and CAI events, there were some differences related to the type of MDR, type of antimicrobials, and type of infection. The current finding can guide training and educational activities of local antimicrobial stewardship initiatives aiming to improve antimicrobial therapy in hospital setting.

Surface modification of helical carbon nanocoil (CNC) with N-doped and Co-anchored carbon layer for efficient microwave absorption.

Surface modification and composition control for nanomaterials are effective strategies for designing high-performance microwave absorbing materials (MWAMs). Herein, we have successfully fabricated Co-anchored and N-doped carbon layers on the surfaces of helical carbon nanocoils (CNCs) by wet chemical and pyrolysis methods, denoted as Co@N-Carbon/CNCs. It is found that pure CNCs show a very good microwave absorption performance under a filling ratio of only 6%, which is attributed to the uniformly dispersed conductive network and the cross polarization induced by the unique chiral and spiral morphology. The coating of N-doped carbon layers on CNCs further enriches polarization losses and the uniform anchoring of Co nanoparticles in these layers generates magnetic losses, which enhance the absorption ability and improve the low frequency performance. As compared with the pure CNCs-filling samples, the optimized Co@N-Carbon/CNCs-2.4 enhances the absorption capacity in the lower frequency range under the same thickness, and realizes the decreased thickness from 3.2 to 2.8 mm in the same X band, as well as the decreased thickness from 2.2 to 1.9 mm in the Ku band. Resultantly, a specific effective absorption wave value of 22 GHz g-1 mm-1 has been achieved, which enlightens the synthesis of ultrathin and light high-performance MWAMs.

Structural Engineering of Hierarchical Aerogels Comprised of Multi-dimensional Gradient Carbon Nanoarchitectures for Highly Efficient Microwave Absorption.

Recently, multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials. Nevertheless, excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges. Herein, the delicate "3D helix-2D sheet-1D fiber-0D dot" hierarchical aerogels have been successfully synthesized, for the first time, by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method. Particularly, the graphene sheets are uniformly intercalated by 3D helical carbon nanocoils, which give a feasible solution to the mentioned problem and endows the as-obtained aerogel with abundant porous structures and better dielectric properties. Moreover, by adjusting the content of 0D core-shell structured particles and the parameters for growth of the 1D carbon nanofibers, tunable electromagnetic properties and excellent impedance matching are achieved, which plays a vital role in the microwave absorption performance. As expected, the optimized aerogels harvest excellent performance, including broad effective bandwidth and strong reflection loss at low filling ratio and thin thickness. This work gives valuable guidance and inspiration for the design of hierarchical materials comprised of dimensional gradient structures, which holds great application potential for electromagnetic wave attenuation.

A state-of-the-art review on wastewater treatment techniques: the effectiveness of adsorption method.

The world's water supplies have been contaminated due to large effluents containing toxic pollutants such as dyes, heavy metals, surfactants, personal care products, pesticides, and pharmaceuticals from agricultural, industrial, and municipal resources into water streams. Water contamination and its treatment have emerged out as an escalating challenge globally. Extraordinary efforts have been made to overcome the challenges of wastewater treatment in recent years. Various techniques such as chemical methods like Fenton oxidation and electrochemical oxidation, physical procedures like adsorption and membrane filtration, and several biological techniques have been recognized for the treatment of wastewater. This review communicates insights into recent research developments in different treatment techniques and their applications to eradicate various water contaminants. Research gaps have also been identified regarding multiple strategies for understanding key aspects that are important to pilot-scale or large-scale systems. Based on this review, it can be determined that adsorption is a simple, sustainable, cost-effective, and environmental-friendly technique for wastewater treatment, among all other existing technologies. However, there is a need for further research and development, optimization, and practical implementation of the integrated process for a wide range of applications.

Interface-Induced Near-Infrared Response of Gold-Silica Hybrid Nanoparticles Antennas.

We proposed an IR absorber hybrid nanoantenna comprise of two overlapping gold nanoparticles residing over larger a silica nanoparticle. A wet chemical route was employed to prepare the hybrid structure of nanoantenna. High-resolution transmission electron microscope was used to measure the size and morphology of the nanoantenna. The Hybrid nanoantenna was excited by electron beam to investigate the optical response over a large wavelength range using Electron Energy Loss Spectroscopy. The beam of the electron was focused and we measured the electron energy loss spectra at different point of interest, which confirmed the of Low Energy Surface Plasmon Politron resonances in the IR region. The optical response of the nanoantenna was simulated numerically by employing Electric Hertzian dipole using finite element method with frequency domain solver in CST Microwave Studio. We used the Electric Hertzian dipole approach for the first time to model the Electron Energy Loss Spectroscopy experiment. The Electron Energy Loss Spectroscopy experimental results with their numerically simulated values confirmed the plasmonic resonance at the interface of the two overlapped gold nanoparticles.

Electrical/thermal behaviors of bimetallic (Ag-Cu, Ag-Sn) nanoparticles for printed electronics.

In this work, Ag-Cu and Ag-Sn nanoparticles (NPs) were synthesized by a physical vapor condensation method, i.e. DC arc-discharge plasma. The as-prepared bimetallic NPs consist of metallic cores of Ag-Cu or Ag-Sn and ultrathin oxide shells of CuO or a hybrid of SnO and SnO2. Ag-Sn NPs exhibit a room-temperature resistivity of 4.24 × 10-5 Ω · cm, a little lower than 7.10 × 10-5 Ω · cm of Ag-Cu NPs. Both bimetallic NPs demonstrate typical metallic conduction behavior with a positive temperature coefficient of resistance over 25-300 K. Ag-Sn NPs exhibit thermally competitive stability up to 230 °C and a lower resistivity of 3.18 × 10-5 Ω · cm after sintering at 200 °C, giving it potential for application in flexible printed electronics.

In situ synthesis and electronic transport of the carbon-coated Ag@C/MWCNT nanocomposite.

A nanocomposite of Ag@C nanocapsules dispersed in a multi-walled carbon nanotube (MWCNT) matrix was fabricated in situ by a facile arc-discharge plasma approach, using bulk Ag as the raw target and methane gas as the carbon source. It was found that the Ag@C nanocapsules were ∼10 nm in mean diameter, and the MWCNTs had 17-32 graphite layers in the wall with a thickness of 7-10 nm, while a small quantity of spherical carbon cages (giant fullerenes) were also involved with approximately 20-30 layers of the graphite shell. Typical dielectric behavior was dominant in the electronic transport of Ag@C/MWCNT nanocomposites; however, this was greatly modified by metallic Ag cores with respect to pure MWCNTs. A temperature-dependent resistance and I-V relationship provided evidence of a transition from Mott-David variable range hopping [ln ρ(T) ∼ T -1/4] to Shklovskii-Efros variable range hopping [ln ρ(T) ∼ T -1/2] at 5.4 K. A Coulomb gap, Δ C ≈ 0.05 meV, was obtained for the Ag@C/MWCNT nanocomposite system.

Novel nanocapsules with Co-TiC twin cores and regulable graphitic shells for superior electromagnetic wave absorption.

The synthesis of nanometer materials with unique structures and compositions has proven successful towards the attenuation of electromagnetic (EM) waves. However, it is still a challenge to form special nanostructures by integrating magnetic/dielectric loss materials into one particle due to the difficulties in coupling the heterogeneous components. Herein, we present the synthesis of novel nanocapsules (NCs) with Co-TiC twin cores encapsulated inside graphitic shells using an arc-discharge plasma method. The thickness of the graphitic shell could be controlled by quantitatively tuning the carbon source concentration. The optimal reflection loss (RL) values of the prepared NCs was -66.59 dB at 8.76 GHz with a low thickness of 2.56 mm. The bandwidth of RL ≤ -10 dB was up to 14.4 GHz, which almost covered the entire frequency band, namely, the S to Ku band (3.6 GHz to 18 GHz). This superior EM wave absorption was ascribed to the specific double-core shell nanostructures and effective impedance matching between the magnetic loss and dielectric loss originating from the combination of the magnetic Co and dielectric TiC/C.

Oil industry waste: a potential feedstock for biodiesel production.

The worldwide rising energy demands and the concerns about the sustainability of fossil fuels have led to the search for some low-cost renewable fuels. In this scenario, the production of biodiesel from various vegetable and animal sources has attracted worldwide attention. The present study was conducted to evaluate the production of biodiesel from the oil industry waste following base-catalysed transesterification. The transesterification reaction gave a yield of 83.7% by 6:1 methanol/oil molar ratio, at 60°C over 80 min of reaction time in the presence of NaOH. The gas chromatographic analysis of the product showed the presence of 16 fatty acid methyl esters with linoleic and oleic acid as principal components representing about 31% and 20.7% of the total methyl esters, respectively. The fourier transform infrared spectroscopy spectrum of oil industry waste and transesterified product further confirmed the formation of methyl esters. Furthermore, the fuel properties of oil industry waste methyl esters, such as kinematic viscosity, cetane number, cloud point, pour point, flash point, acid value, sulphur content, cold filter plugging point, copper strip corrosion, density, oxidative stability, higher heating values, ash content, water content, methanol content and total glycerol content, were determined and discussed in the light of ASTM D6751 and EN 14214 biodiesel standards. Overall, this study presents the production of biodiesel from the oil industry waste as an approach of recycling this waste into value-added products.

SSR Markers Associated with Proline in Drought Tolerant Wheat Germplasm.

Water stress causes major agricultural loss throughout the world as survival of the crops remained under stress and loss in yield. Plants respond to drought stress by means of different adaptive mechanisms such as accumulation of osmoprotectants to counteract the water stress. Amino acid proline is known to occur widely in higher plants and normally accumulates in large quantities as an osmolyte in response to environmental stresses. Biochemical estimation of proline was done in the drought-affected wheat genotypes by spectrophotometric method. Proline promoted a positive effect as root/shoot ratio was enhanced in wheat germplasm under drought stress. SSR primer pairs (45) were tested for polymorphism among selected wheat genotypes. The dendrogram results have shown the wheat genotype association with the levels of proline during induced drought stress. The relationship between pattern of drought responsive biochemical attributes and DNA markers in the selected wheat genotypes was recognized to select drought tolerant genotypes for sowing in drought affected areas of the country.