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In the present work, we numerically and experimentally study the Co 3 - x Ni x O 4 (spinel-like oxides) system. Using the perturbative density functional theory (p-DFT) method, we start the study from the homogeneous sample ( x = 0 ), obtaining the main electronic properties (band structure (BS), density of states (DOS), and Fermi surface (FS)). Subsequently, we doped (x) with Ni atoms in different proportions (0–7% respectively, taking 56 atoms as 100% and the percentage of doping, on this percentage). As we increase the doping (x ≠ 0) , we have found that the forbidden gap decreases and the Fermi energy (FE) decreases, causing the material to exhibit a transition phase for a particular doping value. In addition, we find that more bands are generated when the system is doped, which would be responsible for the phase transition. The data from the theoretical analysis carried out in this paper was compared with the experimental data of various widely accepted works. Some of the results, when compared with the information available from the experimental ones, show good agreement. [ABSTRACT FROM AUTHOR]

In this work, we studied the magnetization and the Cooper pairs density in a conventional superconducting thin square film in the presence of an external magnetic field H. Our investigation was carried out to solve the p -wave-two-band Ginzburg–Landau equations (TB-TDGL) considering a topological-type coupling between the bands. We vary the size of the sample L , the weighty of the coupling γ and the effective Ginzburg–Landau parameter κ eff , as a magnetic field function. We found an interesting vortex configuration and the respective generation of vortex clusters due to the coupling used between condensates. A high (weak) dependence of the first (second) critical field on the weight of the coupling is found. We revealed interesting magnetization curves, their dependence with the size of the sample, the relationship with the coherence length and penetration length and finally with the weight of the coupling between the bands (γ). [ABSTRACT FROM AUTHOR]

In the present research, the synthesis of cobalt oxide Co3O4 was carried out using the sol-gel technique with subsequent heat treatment at 225 and 235 °C. The final product obtained was characterized by X-ray diffraction (XRD), showing a pure crystalline phase of Co3O4, cell parameters a=b=c=8.071 Å, and a volume of 525.7 ų. The particle size was between 2.37 and 2.77 µm, which indicated that structural transformations from Co to Co3O4 induced an increase in the particle size. Through Rietveld refinement, the interatomic distances and inclination angles of the Co1, Co2, and Co3 polyhedra were analyzed in order to establish the structural behavior of cobalt oxide (II, III) at 235 °C. The UV-vis analysis allowed determining band gap (Eg) with values of 1.6 eV in the first region and 0.97 eV in the second. Scanning electron microscopy images showed that the particles agglomerated with increasing calcination temperature and exhibited larger particles. This work presents a detailed analysis of structural parameters of Co3O4 using the Vesta software with Rietveld refinement data. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is commonly associated with obesity and characterized by excessive lipid accumulation and liver inflammation. The T cell immunoglobulin and mucin domain 1 (Tim-1), also known as hepatitis A virus cellular receptor 1 (Havcr-1) and kidney injury molecule 1 (Kim-1), has been shown to affect innate immunity-driven proinflammatory cascade in liver ischemia-reperfusion injury. However, its contribution to obesity-related NAFLD/NASH remains unknown. Thus, this study was designed to evaluate the role of Tim-1 in obesity-related liver inflammation and injury in wild-type (WT) and Tim-1-deficient (Tim-1-/-) C57BL/6J mice fed a high-fat diet (HFD) for 5-6 months. HFD feeding induced steatosis and upregulated Tim-1 gene expression in the liver of WT mice. Surprisingly, Tim-1-/- mice on HFD diet exhibited an exacerbation of hepatic steatosis, accompanied with an elevation of protein levels of fatty acid translocase CD36 and sterol regulatory element binding protein 1 (SREBP1). Tim-1 deficiency also enhanced HFD-induced liver inflammation and injury, as evidenced by augmented increase in hepatic expression of pro-inflammatory factor lipocalin 2 and elevated serum alanine transaminase (ALT). In addition, gene expression of type I, III and IV collagens and liver fibrosis were greatly enhanced in HFD Tim-1-/- mice compared with HFD WT mice. HFD-induced hepatic expression of YM-1, a specific mouse M2 macrophage marker, was further upregulated by deletion of Tim-1. Together, these results show that Tim-1 deficiency aggravates the effects of HFD diet on lipid accumulation and liver fibrosis, most likely through enhanced infiltration and activation of inflammatory cells. [ABSTRACT FROM AUTHOR]

Doped and un-doped 0.5% Er3+ ferroelectric ceramics (1-x)[Pb(1-y)Lay(Mg1/3Nb2/3)O3]-xPbTiO3 (PLMN-PT) were prepared via solid-state reaction using the columbite method and densified by means of conventional sintering (CS), uniaxial hot pressing (HP), and spark plasma sintering (SPS). We review and discuss the influences of the densification process on the microstructural, structural, and dielectric properties of the ceramics. Samples with no porosity or grain size changes caused by the densification process were observed. A density of the ceramics close to the theoretical value (more than 99%) was reached with HP. The heat treatment process in ceramics through SPS eliminates the dark color and improves transparency. Furthermore, the influence of the densification process on the microstructural and structural properties of the ceramics was reviewed and discussed, finding that the electrical properties are favored by HP. [ABSTRACT FROM AUTHOR]

Agglomerates of Co 3 O 4 were obtained using the sol–gel method for the synthesis with subsequent calcination of the samples up to 550 °C. Through X-rays it was observed that the samples presented the pure spinel phase with a crystallite size between 33.73 and 41.45 nm. In the thermogravimetric measurement from 262 °C high structural stability is presented with phase change at 917 °C. As the temperature increases, the particles increase in size, observing agglomerated nanometer particles that increase with temperature (3.5–3.8 μm). The 683 cm - 1 Raman mode for 550 °C clearly presents an shifted compared to the other samples. The band gap for the samples under study varied with the temperature change of 1.77–1.81 eV. The FWHM decreases at a higher temperature, this confirms the larger crystallite size and the higher degree of sintering. [ABSTRACT FROM AUTHOR]

The use of titanium oxide nanotubes in the hydrogen evolution reaction (HER) was studied. Nanotubes were grown on titanium substrates through the anodizing process. Using the X-ray diffraction technique, the structure of the samples was determined. The surface roughness values of the samples after the anodizing process were determined by applying atomic force microscopy. The reaction kinetics were studied through electrochemical impedance spectroscopy and potentiodynamic polarization curves at repeated oxidation-reduction cycles, using a 0.5 M sulfuric acid solution as the electrolyte. Stability in contact with the solution and the establishment of a balance in the load transfer coefficients and the kinetics as a function of hydrogen production cycles were determined using electrochemical impedance spectroscopy and potentiodynamic curve techniques. [ABSTRACT FROM AUTHOR]

Ti K-edge x-ray absorption near-edge spectroscopy (XANES) and Raman scattering were used to study the solid solution effects on the structural and vibrational properties of Pb1-xBaxZr0.65Ti0.35O3 with 0.0

This paper reports on a topographic and tomographic Raman scattering study of the structural and chemical disorders generated by microindentations in indium antimonide. Two different microindentation mechanisms were investigated: mechanical and laser ablations. In the mechanical indentation, three main effects were observed: amorphization, structural pressure induced phase transition from zinc blende to wurtzite structure, and the presence of both compressive and tensile residual strains. On the other hand, an intense irreversible chemical disorder in the laser ablation was observed, the main effect being the segregation of crystalline antimony up to the surface of the indentation mark. [ABSTRACT FROM AUTHOR]

Sm-doped PbTiO3 powder was synthesized by the polymeric precursor method, and was heat treated at different temperatures. The x-ray diffraction, photoluminescence, and UV-visible were used as a probe for the structural order degree short-, intermediate-, and long-range orders. Sm3+ ions were used as markers of these order-disorder transformations in the PbTiO3 system. From the Rietveld refinement of the Sm-doped PbTiO3 x-ray diffraction data, structural models were obtained and analyzed by periodic ab initio quantum mechanical calculations using the CRYSTAL 98 package within the framework of density functional theory at the B3LYP level. This program can yield important information regarding the structural and electronic properties of crystalline and disordered structures. The experimental and theoretical results indicate the presence of the localized states in the band gap, due to the symmetry break, which is responsible for visible photoluminescence at room temperature in the disordered structure. [ABSTRACT FROM AUTHOR]

Maintaining a constant voltage the growth of titanium oxide (T iO2) with a tubular geometry was studied. Therefore, the optimal parameters for the growth of TiO2 were established using an organic electrolytic solution with a total volume of 150ml, composed of water/hydrofluoric acid/ammonium fluoride/ethylene glycol. The anodization conditions were varied, such as: time (60-215 min), electric potential (5-20 V), water content (0.0 - 2.0 ml), and pH (4.8 - 5.1). In this procedure, the conformation of long, open nanotubes with smooth walls was achieved, obtaining a maximum length of 1.90 µm for the nanotubes. However, in some samples before and after annealing a remnant layer can be seen that extends over some regions of the surface of the nanotubes. By means of the current density curves-time (J vs.t), we were able to specify the distinct growth zones of the nanotubes. The samples also were studied structurally by means of X-ray with thermal treatment (ambient-450°C). In addition, it was determined, via ultraviolet-visible (UV-Vis) spectroscopy, that the band gap energy varies (3.45 eV-3.03eV). [ABSTRACT FROM AUTHOR]

In this work a study of the effect of the synthesis conditions on the vibratory and particle size properties in the cupric oxide (CuO) has been presented. The synthesis has been carried out by the polymeric precursor method without modifying the PH in the process, this being a low cost method. The samples obtained have been subjected to several calcination temperatures, 450 °C, 550 °C, 650 °C and 800 °C. In particle analysis by X-ray, scanning electron microscopy (SEM) and statistical it has been observed that for very low or very high calcination temperatures the particle size increases, finding 650 °C as the best calcination temperature. In the Raman spectra, the Ag and Bg vibration have been presented in the samples, with the peaks being narrower for the temperature of 450 °C. [ABSTRACT FROM AUTHOR]

Common methods to detect phlebitis may not be sufficient for patients in the intensive care unit (ICU). The goal of this study was to investigate the feasibility of infrared (IR) thermography to objectively detect phlebitis in adult ICU patients. We included a total of 128 adult ICU-patients in a pilot and subsequent validation study. Median [interquartile range] age was 62 [54–71] years and 88 (69%) patients were male. Severity of phlebitis was scored using the visual infusion phlebitis (VIP)-score, ranging from 0 (no phlebitis) to 5 (thrombophlebitis). The temperature difference (ΔT) between the insertion site and a proximal reference point was measured with IR thermography. In 78 (34%) catheters early phlebitis and onset of moderate phlebitis was observed (VIP-score of 1–3). In both the pilot and the validation study groups ΔT was significantly higher when the VIP-score was ≥1 compared to a VIP-score of 0 (p<0.01 and p<0.001, respectively). Multivariate analysis identified ΔT (p<0.001) and peripheral venous catheter (PVC) dwell time (p = 0.001) as significantly associated with phlebitis. IR thermography may be a promising technique to identify phlebitis in the ICU. An increased ΔT as determined with thermography may be a risk factor for phlebitis. [ABSTRACT FROM AUTHOR]

The kinetics of growth of tubular nanostructures of titanium dioxide (TiO2) obtained by means of the physic-chemical method of electro position under potentiostatic conditions is studied. For this investigation, four tests were carried out where some synthesis parameters were varied in chemical solution: water/fluorhydric acid/ammonium fluoride/ethylene glycol (H2O/HF/NH4F/EG) as well as the conditions of anodization. Therefore, the chemical attack in the anodization process is produced by the NH4F and HF ions. The morphology of the resulting nanotubes was analyzed through scanning electron microscopy (SEM). The average length of the nanotubes was established, with a maximum value of 980 nm. By means of X-ray diffraction of the samples the structure was analyzed, obtaining a mixed phase of anatase and titanium. Using ultraviolet-visible spectroscopy (UV-Vis), the energy gap of the tests was found at different times of anodization. At 60 min of anodization, the energy gap of the samples varied between 3.56 and 3.68 eV. For a time of 30 min anodization, the energy gap of the samples varied between 3.58 and 3.63 eV with the same parameters of chemical synthesis. With obtaining of the curves of the current as a function of the time of anodization (I vs. t), the different stages of growth of the nanotubes and the regions that these stages define were determined. Analyzing of the behavior the current-time graphs and SEM measurements, it was observed that the best solution of the 4 tests used in this work was that of test 1. [ABSTRACT FROM AUTHOR]

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In this paper, we present the experimental results of the photocatalytic properties evaluation of the niobium pentoxide $$\text {Nb}_{2}\text {O}_{5}$$ semiconductor oxide and its performance in processes photoinduced of Rhodamine B and Atrazine degradation, under visible light irradiation. The sample $$\text {Nb}_{2}\text {O}_{5}$$ photocatalysts were synthesized via pechini method. The nanoparticles structure of the samples was studied by X-ray diffraction, Brunauer-Emmett-Teller, Raman spectroscopy, UV-Vis and scanning and transmission electron microscopy. The increase in the calcination temperature during the synthesis resulted in enhanced crystallization, but decreased mesoporosity of the samples. [ABSTRACT FROM AUTHOR]

In this work, we have studied the temperature dependence from 83 to 1300 K in the change of position of Raman modes in single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). The effects of synthesis on the quality and quantity of carbon nanotubes (CNTs) were analyzed with high-resolution scanning electron microscopy (SEM) and micro-Raman spectroscopy. The behavior of the modes G for CNTs with the application of temperatures was studied, and we find that the (G)-peak position shifts to low frequency with increasing temperature. When reducing the ambient temperature to 83 K, there is displacement of the G-mode but not many changes were observed in the other modes. At high temperatures, there are changes in the position and intensity of the different modes. This behavior cannot be understood by purely thermal effects, it may also be due to uniaxial tension. The analysis of the experimental data showed the temperature dependencies of frequencies (w) and linewidths (FWHM). As a result of FWHM and the thermal expansion theoretical data, we calculated the Grüneisen parameter and the phonon decay rate, which are well described, taking into account the contributions from thermal expansion and anharmonicity. [ABSTRACT FROM AUTHOR]

The Raman spectroscopy can be used as a didactic technique in the study of the thermal expansion of Grüneisen parameter and anharmonic behavior of materials. Here, we present exemplary, the lead titanate doped with lanthanum (PLT). However, this method can be used to study various materials. The ferroelectric ceramics have been one of the most studied compounds in the literature both in obtaining the same, as in behavior of chemical and physical properties. The structural 3 phase may change either by the application of pressure, temperature or concentration, thereby allowing a study of behavior anharmonic of the material [M. R. Joya, J. Barba and P. S. Pizani, J. Appl. Phys. 113 (2013) 013512]. This paper gives a brief review of the effect of temperature and pressure on Raman spectra. [ABSTRACT FROM AUTHOR]

The article presents a study of the effects temperature and lanthanum (La) concentration in the formation of A1 transverse optical phonon in the ceramic titanate (PbTiO3) system. It uses Raman scattering to examine the structural phase transition from ferroelectric to paraelectric in the(PbTiO3) doped with La. It demonstrates that the anomalous behavior of A1 mode is influenced by La concentration, temperature and anharmonicity and defects in (PbTiO3) network.

Increasing global warming due to NO x , CO 2 , and CH 4 , is significantly harming ecosystems and life worldwide. One promising methodology is converting pollutants into valuable chemicals via photocatalytic processes (by reusable photocatalysts). In this context, the present work aimed to produce a Nb 2 O 5 photocatalyst nanofiber system by electrospinning to convert CO 2 . Based on the collected data, the calcination at 600 ∘ C for 2 h resulted in the best condition to obtain nanofibers with homogeneous surfaces and an average diameter of 84 nm. As a result, the Nb 2 O 5 nanofibers converted CO 2 mostly into CO and CH 4 , reaching values around 8.5 μ mol g − 1 and 0.55 μ mol g − 1 , respectively. [ABSTRACT FROM AUTHOR]

A detailed Raman scattering study was performed on lanthanum-modified lead titanate (PLT) with compositions varying from pure PbTiO3 to La 20.0 at. %, for temperatures ranging from 8 K to temperatures above the Curie temperature and hydrostatic pressures up to 7.5 GPa. A complete La concentration-pressure-temperature three dimensional phase diagram was determined, by using the E(TO1) soft mode frequency as the main probe. [ABSTRACT FROM AUTHOR]

Photoluminescence at room temperature in Ba(Zr0.25Ti0.75)O3 thin films was explained by the degree of structural order-disorder. Ultraviolet-visible absorption spectroscopy, photoluminescence, and first principles quantum mechanical measurements were performed. The film annealed at 400 °C for 4 h presents intense visible photoluminescence behavior at room temperature. The increase of temperature and annealing time creates [ZrO6]–[TiO6] clusters in the lattice leading to the trapping of electrons and holes. Thus, [ZrO5]–[TiO6]/[ZrO6]–[TiO6] clusters were the main reason for the photoluminescence behavior. [ABSTRACT FROM AUTHOR]

We investigated the distribution of comorbidities among adult tuberculosis (TB) patients in Chiapas, the poorest Mexican state, with a high presence of indigenous population, and a corridor for migrants from Latin America. Secondary analysis on 5508 new adult TB patients diagnosed between 2010 and 2014 revealed that the most prevalent comorbidities were diabetes mellitus (DM; 19.1%) and undernutrition (14.4%). The prevalence of DM in these TB patients was significantly higher among middle aged (41-64 years) compared with older adults (⩾65 years) (38.6% vs. 23.2%; P < 0.0001). The prevalence of undernutrition was lower among those with DM, and higher in communities with high indigenous presence. Immigrants only comprised 2% of all TB cases, but were more likely to have unfavourable TB treatment outcomes (treatment failure, death and default) when compared with those born in Chiapas (29.5% vs. 11.1%; P < 0.05). Unfavourable TB outcomes were also more prevalent among the TB patients with undernutrition, HIV or older age, but not DM (P < 0.05). Our study in Chiapas illustrates the challenges of other regions worldwide where social (e.g. indigenous origin, poverty, migration) and host factors (DM, undernutrition, HIV, older age) are associated with TB. Further understanding of these critical factors will guide local policy makers and health providers to improve TB management. [ABSTRACT FROM AUTHOR]

SummaryThe Triatomine bug Belminus herreri, previously known only from Panama, is reported for the first time from Colombia. Three adult B. herreri were collected from a chicken coop and a viable egg was found on a Bactris palm at Carmen municipality in humid forest zone at 680 m altitude. From 44 eggs produced, five progeny were reared to adulthood. During early instars they were unable to take bloodmeals directly from vertebrate hosts, but they fed successfully by cleptohaematophagy on blood from replete Rhodnius prolixus. [ABSTRACT FROM AUTHOR]