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In recent times, ultra-thin films of hafnium oxide (HfO2) have shown ferroelectricity (FE) attributed to the orthorhombic (o) phase of HfO2 with space group Pca21. This polar o-phase could be stabilized in the doped thin film of the oxide. In the present work, both polar and non-polar o-phases of HfO2 could be stabilized in Gd-doped bulk polycrystalline HfO2. Rietveld analysis of XRD data shows that the relative population of o-phases in the presence of the monoclinic (m) phase of HfO2 increases with increasing Gd-content. The local environment around the host atom has been investigated by time differential perturbed angular correlation (TDPAC) spectroscopy, synchrotron based X-ray near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) measurements showed a reduction in grain size with increasing Gd-dopant indicating a solute drag effect. It could be established that the segregation of the Gd-dopant in the grain boundary is a thermodynamically favorable process and the solute drag effect plays an important role in nucleation of the o-phase in bulk HfO2. Stabilization of Gd in both Pbca and Pca21 phases of HfO2 was supported by defect formation energy calculations using density functional theory (DFT). The present study has important implications in future applications of HfO2 in ferroelectric devices and in understanding the role of dopants in stabilizing the o-phase of HfO2 in the bulk. [ABSTRACT FROM AUTHOR]

The recently observed ferroelectricity in thin films of pure and doped Hafnium oxide (HfO2) has initiated a sustaining effort to stabilize its ferroelectric phase which is the polar orthorhombic (o) phase with space group Pca21. This polar o-phase of the oxide does not appear in its phase transition sequence and is also not thought to be stabilized in bulk oxide. Here, we report the stabilization of three o-phases of this oxide in bulk with space groups Pbca, Pca21 and Pbcm in presence of Yttrium (Y) dopant. For inducing o-phase, 10 at% of Y-dopant has been used and temperature mediated phase transformation from monoclinic (m) to o-phase has been observed. The third o-phase with space group Pbcm could be stabilized for the first time in bulk oxide by Y-dopant. All the o-phases in presence of m-phase could be identified by Time Differential Perturbed γ-γ Angular Correlation (TDPAC) Spectroscopy. The TDPAC parameters assigned to Pbcm phase confirm the theoretical modelization for the phase performed by Wien2K calculation based on Density Functional Theory (DFT). The present work reports the possibility of stabilizing different o-phases including polar one and shows the widening of scope of this oxide for future ferroelectric applications. [ABSTRACT FROM AUTHOR]

The recent observation of ferroelectricity in ultra thin films of hafnium oxide (HfO2) has been attributed to the orthorhombic (o) phase of HfO2 with space group Pca21. Although this oxide is polymorphic in nature, this polar o-phase is known to be stabilized in the doped thin film oxide. The objective of the present experiment is to stabilize the o-phases in La doped bulk polycrystalline HfO2 and investigate their evolution with the doping concentration through Time Differential Perturbed Angular Correlation (TDPAC), X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) measurements. The present work reports the presence of both the polar Pca21 phase and the antipolar Pbca phase at different La-concentrations. Two o-phases of HfO2 with space groups Pca21 and Pbca, difficult to distinguish by other complimentary methods, could be unambiguously identified by utilizing the atomic scale sensitivity of the electric field gradient (EFG) embedded in TDPAC spectroscopy. The determination of the oxidation state and the local environment of La-atoms by XANES and EXAFS measurements illuminates the microscopic role of the dopant in stabilizing the o-phase. The "solute drag model" proposes a critical crystallite size for the nucleation of the o-phase in bulk HfO2 and explains the role of the La-dopant in stabilizing the o-phase. Thus the present study shows the possibility of stabilizing the polar o-phase and hence attaining ferroelectricity in bulk HfO2 to augment the scope of future application for this ferroelectric device. [ABSTRACT FROM AUTHOR]

Our aim is to study critical point equation conjecture on a compact (k; Ā)-almost co-Kahler manifold. We prove that if a compact (k; Ā)-almost co- Kahler manifold of dimension greater than three satisfies critical point equation, then either is constant or the manifold is an Einstein manifold provided k < 0. [ABSTRACT FROM AUTHOR]

We report on the study of hafnium oxide thin films grown by pulsed laser deposition at various partial oxygen pressures by Time Differential Perturbed Angular Correlations using the nuclear probe 181Hf(β-)181Ta to determine the nuclear quadrupole interaction (NQI), and by x-ray diffraction. The samples were neutron activated and measured at room temperature as received as well as after annealing in air. All spectra exhibited two to three inequivalent probe sites, even after annealing. At 0.3 mbar oxygen partial pressure and annealing for 5 hs at 1073 K the majority (88%) of the sites exhibited NQI parameters as reported for the bulk monoclinic phase [ωQ = 125.4(2) Mrad/s, η = 0.335(5)]. We can exclude amorphous as well as cubic and tetragonal hafnium oxide phases in the annealed samples. There was no indication of room-temperature ferromagnetism. [ABSTRACT FROM AUTHOR]

IntroductionMexico was the first country in the Americas and the third in the world to eliminate trachoma as a public health problem, as validated by the WHO in 2017.ObjectiveTo describe the critical elements that favored the elimination of trachoma as a public health problem in Mexico and the public health impact of this success.MethodologyA revision and compilation of data and information contained in the dossier presented by the country to PAHO/WHO to obtain the validation of trachoma elimination as a public health problem was conducted by a group of delegates from the national and local trachoma prevention and control program. Data from the national and local surveillance systems and reports of actions conducted after achieving the elimination goal were also included. Critical elements that favored the achievement of the elimination goal from 1896 to 2019 were extracted.ResultsMexico reached the elimination of trachoma in 2016 obtaining the validation in 2017. 264 communities were no longer endemic and 151,744 people were no longer at risk of visual impairment or possible blindness due to trachoma. The key to the success of this elimination process was primarily the local leadership of health authorities with sustained funding for brigades, increased access to potable water and sanitation, and key alliances with indigenous authorities, health authorities, and government institutions that contributed to the achievement of the goal. The SAFE strategy started implementation in Mexico in 2004 as a comprehensive package of interventions. SAFE stands for surgery, antibiotics, facial cleanliness, and improvement of the environmental conditions. These actions impacted drastically on the number of new cases trachmatous trichiasis (TT) and trachomatous inflammation-follicular (TF), which decreased from 1,794 in 2004 to zero in 2016.ConclusionsThe elimination of trachoma as a public health problem in Mexico is a true success story that may serve as a model example for the elimination of other neglected infectious diseases in the Americas.

Dimethoate (organophosphate insecticide) and Lambda-cyhalothrin (synthetic pyrithroid) are two frequently used pesticides due to their high effectiveness and rapid breakdown into environmentally safe products. The aim of this present study was to assess and compare the acute toxicity of Dimethoate (Rogor30%EC) and Lambda-cyhalothrin (5%EC) on Labeo rohita (Hamilton). Acute toxicity bioassay was carried out in a static renewal system to assess the toxicity. The fishes were exposed to different concentration of dimethoate and Lambda-cyhalothrin to determine the LC50 values for 96hrs. The mortality data obtained were analyzed by SPSS 16.0 based on Finney's Probit Analysis Statistical method. The 96h LC50 values for Dimethoate and Lambda-cyhalothrin were found to be 24.55 μl/L and 0.7 μl/L respectively. Effects of these two insecticides on serum T3, T4 and TSH were investigated under sub-lethal toxicities which cause decrease in the serum T3, T4 and increase in TSH level. It shows significant difference from control fish (p < 0.05). [ABSTRACT FROM AUTHOR]

A new set point weighting technique is proposed to improve the set point response and load rejection characteristics of Ziegler-Nichols tuned PID controller (ZNPID). Instead of a fixed or multi-valued set point weighting factor, here dynamic set point weighting is suggested based on the change of error (Δe) of the controlled variable and normalized dead time (θ) of the process under control. Effectiveness of the proposed scheme is tested on high-order linear and nonlinear dead time processes for both set point change and load disturbances. Performance of the proposed PID controller with dynamic set point weighting (DSWPID) is compared with those of a PID controller with variable set point weighting (VSWPID) reported in the leading literature and ZNPID in terms of several performance indices. The result demonstrates a significantly improved overall performance of DSWPID. The proposed scheme can be easily incorporated in an existing control loop. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Miltefosine, the first oral anti-leishmanial drug, is reported to inhibit phosphatidy-linositol 3-kinase (PI3K)/Akt activity in carcinoma cell lines. Inhibition of the PI3K/Akt pathway is known to result in insulin resistance. Therefore, we investigated whether miltefosine has any deleterious effect(s) on insulin sensitivity in L6E9 skeletal muscle cells. Materials and methods: L6E9 myotubes were treated with miltefosine and its effect was observed on insulin-signalling proteins such as Akt, PI3K, insulin receptor-β, IRS-1, c-Jun N-terminal kinase, p38 and glycogen synthase kinase β, as well as on glucose uptake. Results: Miltefosine caused skeletal muscle insulin resistance in vitro by interfering with the insulin-signalling pathway and inhibiting insulin-stimulated glucose uptake. Conclusions/interpretation: Miltefosine may contribute to the risk of type 2 diabetes and needs further clinical exploration [ABSTRACT FROM AUTHOR]

The lifetimes of the 615 and 619 keV levels in181Ta have been remeasured by using a-delayed coincidence set up with fast plastic (Pilot U) and BaF2 detectors. The presently measured values for both levels have been found to be in strong disagreement with results reported earlier. For the 615 keV level, the half-life has been found to bens in striking contrast to the earlier reported value of 17.6s. The half-life of the 619 keV level has been found to beps, whereas values of 0.87 ns and 2.4 ns were reported previously. The nanosecond half-life of the 615 keV level has been confirmed from a separate measurement by employing a NaI(Tl)-Pilot U detector combination. The importance of lifetime measurements for the 615 keV level in perturbed angular correlation studies is discussed. [ABSTRACT FROM AUTHOR]

Strong evidence of atomic “after effects” following β--decay of 181Hf was observed from perturbed angular correlation (PAC) studies in different viscous and non-viscous molecular solutions and in ionic as well as non-ionic solutions. In non-viscous acetone and H2O solutions, the PAC spectra have been found to be completely different to what was expected considering molecular motions in these media. Similarly, in the glycerol–H2O system, PAC spectra remain significantly unchanged with the change of viscosity indicating that molecular motions are not reflected in these media. Rather, perturbations from the interaction of the nucleus-excited atomic state, which was so far considered to be absent for 181Hf β--decay, have been found to be dominant. The atomic shell recovery times in molecular liquids have been found to be in the range 50–150 nsec. In insulating solid HfCl4 medium, however, the PAC spectrum indicates that the atomic shell following 181Hf β--decay remains unchanged within the lifetime of the intermediate state. The lifetime for the 615 keV level has been remeasured and a value of T1/2=12.1±0.1 nsec only has been obtained. This value, although in strong disagreement with the earlier reported value (17.83 μsec), helps explain atomic “after effects” in 181Hf β--decay. [ABSTRACT FROM AUTHOR]