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Today, great emphasis is placed on the creation of lead-free compounds that may be used in multi-functional equipment. This report describes the synthesis (through the solid-state technique) and physical characteristics (structural, electrical, and ferroelectric) of a polycrystalline Sr3Bi2WO9 compound (SBWO). A monoclinic crystal structure with cell parameters; a = 9.0285 Å, b = 16.6457 Å, c = 5.6787 Å with β = 93.13° is studied by analysis of X-ray diffraction method (crystallite size 100.77 nm). The purity, morphology, and elementary composition of elements were studied by SEM (grain size 0.582 μm) and EDX. The temperature-frequency variation of εr, tan δ, and σac were investigated. The drop in grain resistance value with increasing temperature demonstrates the NTCR property of the compound. It has been reported that the conduction process of the compound is based on a study of the modulus spectrum. SBWO is a possible choice for devices because it exhibits outstanding temperature-independent εr characteristics and reduced tanδ. Ferroelectric properties of the material (Ec=0.2655 kV/cm, Pr=0.00454 μC/cm2, Emax=2.478 kV/cm, and Pmax=0.0367 μC/cm2) shown by the electric field-dependent polarization at 25 °C. [ABSTRACT FROM AUTHOR]

Synthesis (via solid-state reaction) and characterization (structure, microstructure, dielectric, electrical, and ferroelectric behavior) of brownmillerite polycrystalline material NaBiFe2O5 (NBFO) are discussed in this paper. The formation of a triclinic structure has been analyzed by the X-ray diffraction method. The morphology of the ceramic sample was analyzed using a field emission scanning electron microscope (FESEM) and energy-dispersive X-ray analysis (EDX). It is found that the grains are uniformly distributed through well-defined grain boundaries of the sample containing all the constituent elements (Na, Bi, Fe, and O). The study of both frequency (1 kHz–1MHz) and temperature (25–450 °C) dependent dielectric and AC-conductivity predicts the presence of Maxwell-Wagner type of dielectric dispersion and thermally activated relaxation mechanism of NBFO. The impedance spectra support the semiconducting behavior of the brownmillerite NBFO at high temperature. The resistance of the material falls with a rise in temperature favors the negative temperature coefficient resistance behavior of the material. The study of electric polarization suggests the possibility of the ferroelectric properties of the studied sample. The high dielectric constant and low tangent loss suggest the possibility of the material for device applications. [ABSTRACT FROM AUTHOR]

Today, great emphasis is placed on the creation of lead-free compounds that may be used in multi-functional equipment. This report describes the synthesis (through the solid-state technique) and physical characteristics (structural, electrical, and ferroelectric) of a polycrystalline Sr3Bi2WO9 compound (SBWO). A monoclinic crystal structure with cell parameters; a = 9.0285 Å, b = 16.6457 Å, c = 5.6787 Å with β = 93.13° is studied by analysis of X-ray diffraction method (crystallite size 100.77 nm). The purity, morphology, and elementary composition of elements were studied by SEM (grain size 0.582 μm) and EDX. The temperature-frequency variation of εr, tan δ, and σac were investigated. The drop in grain resistance value with increasing temperature demonstrates the NTCR property of the compound. It has been reported that the conduction process of the compound is based on a study of the modulus spectrum. SBWO is a possible choice for devices because it exhibits outstanding temperature-independent εr characteristics and reduced tanδ. Ferroelectric properties of the material (Ec=0.2655 kV/cm, Pr=0.00454 μC/cm2, Emax=2.478 kV/cm, and Pmax=0.0367 μC/cm2) shown by the electric field-dependent polarization at 25 °C. [ABSTRACT FROM AUTHOR]

Synthesis (via solid-state reaction) and characterization (structure, microstructure, dielectric, electrical, and ferroelectric behavior) of brownmillerite polycrystalline material NaBiFe2O5 (NBFO) are discussed in this paper. The formation of a triclinic structure has been analyzed by the X-ray diffraction method. The morphology of the ceramic sample was analyzed using a field emission scanning electron microscope (FESEM) and energy-dispersive X-ray analysis (EDX). It is found that the grains are uniformly distributed through well-defined grain boundaries of the sample containing all the constituent elements (Na, Bi, Fe, and O). The study of both frequency (1 kHz–1MHz) and temperature (25–450 °C) dependent dielectric and AC-conductivity predicts the presence of Maxwell-Wagner type of dielectric dispersion and thermally activated relaxation mechanism of NBFO. The impedance spectra support the semiconducting behavior of the brownmillerite NBFO at high temperature. The resistance of the material falls with a rise in temperature favors the negative temperature coefficient resistance behavior of the material. The study of electric polarization suggests the possibility of the ferroelectric properties of the studied sample. The high dielectric constant and low tangent loss suggest the possibility of the material for device applications. [ABSTRACT FROM AUTHOR]

A lead-free brownmillerite ferroelectric material LiBiFe2O5 (LBFO) has been synthesized via a solid-state reaction technique. Using the procedure of N-TREOR method of X-ray diffraction, the crystal structure of the prepared sample is found to be monoclinic with lattice parameters: a = 13.6726 Å, b = 4.1560 Å, c = 8.5317 Å, and β = 102.89˚. Based on analysis of electrical data, the existence of Koop's and Maxwell–Wagner relaxation phenomena and dielectric relaxation in the material has been confirmed. This analysis has also shown a high impact of the dielectric permittivity (ϵr) and low tangent loss (tanδ) on using the material in some electronic devices. A detailed study of the frequency-temperature-dependent ac conductivity has suggested the presence of Jonscher's universal power law in the material. As the material has thermistor constant (β) values of 4019.26, 11535.75, and 484.36 in different temperature ranges indicating high-temperature NTC thermistor application. [ABSTRACT FROM AUTHOR]

A newly designed lead-free complex ceramic with the chemical formula Ca3Bi2MoO9 has been synthesized using a conventional solid-state reaction technique. The structure, microstructure, resistive, dielectric, and conductivity characteristics have been experimentally tested. Analysis of the X-ray diffraction spectrum suggests the sample has monoclinic crystal symmetry (a = 10.639 Å, b = 9.674 Å, c = 6.396 Å, β = 93.794°). The lattice strain and average crystallite sizes are − 0.00114 and 24.17 nm. The compactness and quality of the material have been analyzed by FESEM and EDX spectrum. The fabricated and newly designed electronic material have effective temperature and frequency-dependent electrical characteristics. The study of the conductivity of the material confirms the Universal power law. Analysis of Impedance spectroscopy data (temperature and frequency dependent) confirms that the presence of grains and grain boundaries are responsible for the resistivity properties of the material. A depressed semicircular arc (at 450 °C) with an angle of 2.82° elaborate the non-Debye relaxation phenomena. High dielectric permittivity, minimal tangent loss, and negative temperature coefficient response are observed in the material. [ABSTRACT FROM AUTHOR]

Sonic crystals (SCs) are unique periodic structures designed to attenuate acoustic waves in tunable frequency bands known as bandgaps. Though previous works on conventional uniform SCs show good insertion loss (IL) inside the bandgaps, this work is focused on widening their bandgaps and achieving better IL inside the bandgaps by using a gradient-based sonic crystal (GBSC). The GBSC applies property gradient to the conventional SC array by varying its basic properties, i.e., the distance between the scatterers/resonators (lattice constant), and resonator dimensions between the columns and hence the name GBSC. The design of the GBSC is backed by the results of acoustic beamforming experiments conducted over the uniform SCs of hollow scatterers and Helmholtz resonators (HRs) having two-dimensional (2D) periodicity prepared by using Polyvinyl chloride (PVC) pipes without any property gradient and their respective 2D finite element (FE) studies. The experimental and FE simulation results of the uniform SCs were found to be in good agreement and therefore, the GBSC was modeled and analyzed using FE method considering the viscothermal losses inside the resonators. The results indicated that the property gradient improves both Bragg scattering and Helmholtz resonance compared to that of the uniform SCs and therefore, the GBSC exhibits wider attenuation gaps and higher attenuation levels. An array of 30 microphones was used to conduct acoustic beamforming experiments on the uniform SCs. Beamforming was found to be an advanced and fast method to perform quick measurements on the SCs. [ABSTRACT FROM AUTHOR]

Posttraumatic herniation of brain and CSF into the eyelid is a rare entity with few reported cases in the literature. A 5-year-old girl presented to us with severe periorbital edema and conjunctiva prolapse after 7 days of head trauma. Clinical suspicion of CSF leakage accumulating in lid and periorbita was suspected. CT and MRI scan brain showed multiple comminuted frontal bones, orbital roof, and orbital rim fractures with contused brain tissue herniation through the dural defect. Craniotomy with dural repair was done after which patient improved and within 2 weeks both periorbital edema and conjunctiva prolapse subsided. [ABSTRACT FROM AUTHOR]

Polymyositis (PM) is an uncommon inflammatory myopathy that affects striated muscles. It causes weakness of the limb girdles, neck, and pharyngeal muscles. We are presenting a case of PM which manifested after intrauterine death (IUD). The patient was referred to our hospital for breathing difficulty, 4 days after delivery of a dead fetus. Initially, she was treated in line of puerperal sepsis and peripartum cardiomyopathy. Patient's cardiopulmonary functions improved but she had persistent high-grade fever. Gross muscle weakness was found on day 5 of admission, involving all four limbs, predominantly in proximal muscles and she had dark colored urine. Laboratory tests revealed myoglobinuria, high serum creatine phosphokinase (CPK) levels, and high lactate dehydrogenase (LDH) levels. Polymyositis diagnosed on the basis of high CPK levels, magnetic resonance imaging (MRI) of cervical spine, electromyography (EMG), and muscle biopsy findings. We question, whether the PM could be pathogenically related to the pregnancy? Literature review of the previously reported cases of PM/dermatomyositis and our case report suggests that pregnancy can trigger the new onset of PM. [ABSTRACT FROM AUTHOR]

Due to anthropogenic as well as by natural factors the climate of earth is predicted to be warm by an average of 2-4 °C, at the end of the 21st Century. Emission of green house gases (GHG) from agricultural system is one of the major contributing factor in global warming. Heat stress is one of the major abiotic stresses threatening plant growth worldwide. Agricultural crops suffer in presenting their optimum yield potential due to heat stress. Heat stress causes enormous alterations in various processes within the plant system; most of them are well understood from various physiological, biochemical and molecular studies. Heat stress not only affects the morphological and phenological parameters but also the physiological and biochemical parameters like plant water relationship, photosynthesis, assimilate partitioning, hormonal changes, cell membrane stability, production of secondary plant metabolites, antioxidative metabolism, synthesis of heat shock proteins, cell signalling etc. In the advent of climate change and subsequent global warming there is an urgent need for understanding the physiological and biochemical basis of heat stress tolerance in crop plants. There has been a lot of effort worldwide in this regard to develop high temperature tolerant genotypes through transgenic intervention and genetic engineering. This paper reviews the literature supporting evidence for the morphological, phenological, physiological and biochemical effects of heat stress on several plants and different molecular approaches to develop transgenics tolerant to high temperature stress. A plethora of these kinds of plant responses are finally regulated by the genes. Hence, more biotechnological and molecular studies including genomics, proteomics, metaboliomics and the cryptomics are necessary to elucidate the processes further. [ABSTRACT FROM AUTHOR]

This article reports the development and characterizations (structural, surface topographical, fractal, dielectric, transport, impedance, resistive, and current-voltage properties) of a defect brownmillerite material KBiFeMnO 5 . Preliminary investigation of the X-ray diffraction (XRD) pattern with the Monte Carlo technique with McMaille 4.0 shows monoclinic symmetry having lattice parameters: a = 8.261 Å, b = 8.251 Å, c = 7.524 Å, and β = 108.58°. The analysis of the Williamson-Hall plot illustrates the average crystallite size and micro-lattice strain are 124.6 nm and 0.002, respectively. The scanning electron microscopic image examines the microstructural surface topography, fractal analysis, and surface roughness (using the standard of ISO25178) of the material. Maxwell-Wagner dielectric dispersion, relaxation, and transport mechanisms are investigated utilizing dielectric, impedance, and conductivity spectra accumulated within the experimental frequency (1 kHz to 1 MHz) and temperature (25-500 °C) ranges. The energy band of an intrinsic region with a 1 MHz frequency indicates the semiconducting behavior of the material. The logarithmic current density and electric field are used to investigate the presence of ohmic and space charge limited conduction (SCLC) mechanisms. The thermistor constant ( β ) is determined to be 4633.86, and the temperature coefficient of resistance (TCR) is -0.00322, which may be suitable for high-temperature NTC thermistors and other related device applications., Competing Interests: The authors confirm that the research presented in this work has not been influenced by any known financial conflicts of interest or close personal ties. In addition to the above, we have no conflicts of interest with anybody except Paweł E. Tomaszewski., (This journal is © The Royal Society of Chemistry.)