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Iron-containing garnets (YIG) were used as catalysts for selective oxidation of ethylbenzene (EB) in the presence of H2O2 as oxidant. The catalysts comprising of two series of garnets e.g., Y3(Fe1–xZnx)5O12 and Y3(Fe1–xNix)5O12 had distinct Zn and Ni contents (x = 0.00 0.01, 0.03, and 0.05). XRD, Raman and FTIR spectroscopies revealed that the cubic structure of Y3Fe5O12 garnet was present for x = 0.00 and 0.01. For higher contents, the garnets had the Y3Fe5O12 phase besides hematite (α-Fe2O3). The catalytic activity was dependent on the contents of metals in the garnets with Y3Fe4·97Ni0·03O12-γ and Y3Fe4·95Zn0·05O12-γ catalysts achieving better results. The influence of the reaction conditions such as reaction time, reaction temperature and effect of the solvents as well as the substrates to H2O2 molar ratios were studied. SEM-EDS, XPS and EPR results demonstrated the affinity of the Fe2+/Fe3+ pairs with Ni2+ species for the ethylbenzene molecule, which gave an EB conversion of 77% with a good production of acetophenone over the Y3Fe4·97Ni0·03O12-γ catalyst compared to other binary and ternary solids.

In the present work, we have studied the competitive effect of Er and Cr dopants on the structural and magnetic properties of yttrium iron garnet (YIG) nanoparticles synthesized by the sol gel method. The YIG single phase was obtained for all samples and the variations of structural parameters were associated to the dopants influence. Fourier transform infrared spectroscopy showed typical absorption peaks of YIG, with small displacements for larger wavenumbers corresponding to vibrational modes (Fe–O) belonging to the tetrahedral sites. The behavior of the Raman vibrational modes as a function of dopant concentration confirms the insertion of Er in dodecahedral sites and Cr in the octahedral and tetrahedral sites. A frequency shifting of some Raman modes was observed as the Cr concentration increased. The powder morphology was analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), evidencing agglomerated particles with irregular shapes. The Er and Cr incorporation in YIG promote random fluctuations in the saturation magnetization, coercivity and the magnetocrystalline anisotropy constants of the synthesized compound.

In developing countries, death due to diseases caused by fecal-oral ingestion can be avoided by taking action on drinking water issues. Adequate access to water treatment systems to reduce infections is a critical cause. Silver has been used as an antibacterial product, including biomedical applications. Therefore, in this paper, the effect of the chemical speciation of silver from silver-modified zeolite-rich tuffs on the mortality of Escherichia coli (E. coli), Streptococcus faecalis (S. faecalis) and Candida albicans (C. albicans) suspended in aqueous solution was investigated for disinfection purposes. The following aspects were considered to develop the investigation: a) the technique to prepare the modified zeolitic materials, either with ionic silver or silver nanoparticles, which were obtained in two ways: one, with grapefruit extract and the second, by using non-thermal plasma generated in a dielectric barrier discharge reactor of parallel plates; b) the response of the prokaryotes (bacteria) and eukaryote (yeast) microorganisms to disinfectant agents in batch systems; c) the disinfection processes as a function of time to obtain kinetics parameters; and d) the kinetics of the silver release from the silver-modified zeolite-rich tuffs, considering the models of Higuchi and Korsmeyer. The zeolitic materials were characterized by low-vacuum scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The non-thermal plasma reduced ionic silver is more efficient at generating silver compounds with several oxidation states, which are essential during the microbial inhibition process. For the bacterial (E. coli and S. faecalis), the materials with nanoparticles were efficient to inactivate them. However, the yeast (C. albicans) reaches the total inactivation when the zeolitic material contains ionic silver in the crystalline network. The E. coli, S. faecalis and C. albicans survival behavior suspended in aqueous solutions after contact with Ag-modified natural zeolites depends on the chemical speciation of the silver present in these materials, Ag+1 in the case of OAgiZ or nanoparticles of Ago promoted by the grapefruit extract (OAgnpTZ), as well as by non-thermal plasma generated in a dielectric barrier discharge reactor of parallel plates (OAgnpPZ). In general, the concentration of silver in the aqueous solution after the disinfection process cannot exceed the recommended levels established for international organizations. The OAgnpPZ is a potential microbicide agent against E. coli and C. albicans, and the OAgnpTZ for F. faecalis.

A novel TiO2 photocalayst was synthesized by sol-gel method in the presence of Arabic (AGTi) and Karaya gums (KGTi). The composites were structurally and morphologically characterized by different techniques and the photocatalytic activity was investigated using methylene blue (MB) dye as model pollutant. In addition, the stability, recycle, effect of scavengers, and toxicity were investigated. The composites presented spherical structure and the nucleation of TiO2 particles was modified in presence of the gums. All the materials showed presence of the anatase phase and the textural properties indicated mesoporous and high surface area. The band gap was approximately 2.9 eV for the both materials; however the recombination process was more favored in KGTi. The C/C0 ratio of AGTi and KGTi decreased after 150 min of radiation. The electron plays the dominant role in photocatalytic process in both composites. The photocatalysts demonstrated stability after 3 runs and toxicity was not evidence in both composites. Hence, the composites showed excellent photocatalytic performance for MB discoloration.

In the present work experimental data for saturation magnetization at low temperatures, of yttrium iron garnet nanoparticles are different from that expected by the T3/2 Bloch's Law. This result is mainly conditioned by the local atomic disorder induced during the nanoparticles preparation by using the sol gel method. To correctly describe the experimental curves, a fitting using Cojocaru's theory was performed because the model uses geometric and other conditions in agreement with our experimental results. The magnetic ions localized at the nanoparticles surface, outside the crystalline periodicity, are the responsible by the saturation magnetization behavior presented here.

The presence of drugs in aquatic bodies is a prevailing issue, and their removal by adsorption is an effective treatment. Among the adsorbents, those based clay minerals have been proposed. Bentonite is a clay mineral that is widely studied as an adsorbent due to its unique physicochemical properties, such as cation exchange capacity (CEC), intercalation, and adsorption. The properties of bentonites can be improved through chemical modifications, such as the incorporation of organic and/or inorganic compounds. These modifications allow for the efficient removal of different contaminants, including pharmaceutical compounds. In this work, raw sodium bentonite (Na+-Bent) and vanadyl bentonites were prepared using 100 (BentV1), 300 (BentV3), and 500% (BentV5) of the cationic exchange capacity of the Na+-Bent and further used for amiloride removal from aqueous solution. Analysis of X-ray fluorescence and Na+ in solution after interaction indicated that the principal mechanism of interaction between bentonite and ions was the ion exchange between sodium of the matrix and vanadyl in solution. Infrared spectroscopy suggested the contribution of coordination of the interlayer water with the vanadyl ions and hydrogen bonding between vanadyl and structural OH. X-ray diffraction analysis indicated that vanadyl ions were incorporated onto Na+-Bent. Amiloride adsorption was better at pH 5.8, using a solid dosage of 75 mg of Na+-Bent, 25 mg of BentV1 and BentV5, and 50 mg of BentV3. The adsorption occurred briefly until 20 min, and maximum removal values were 457.08, 374.64, 102.56, and 25.63 mg·g−1 for Na+-Bent, BentV1, BentV3, and BentV5, respectively. At lower drug concentrations (48.78 and 91.24 mg·g−1 for Na+-Bent and BentV3), the best performance was obtained for the BentV3 sample.

In this paper, we present a study about the remanence state and coercivity in 1-D chain of cobalt hollow nanospheres, by using micromagnetic simulation. The high coercivity values ( ${H_{c}}$ is determined in the range of 600–1800 Oe) and the monotonic decrease of remanence are attributed to the shape anisotropy effect due to an increase in the aspect ratio value. The configuration of magnetization in remanence showed the onion state for hollow spheres (HSs) with ${R_{e} = 15}$ nm, whereas for ${R_{e} = 30}$ nm, appear the curling-vortex (CV) state. Finally for a cluster of chains, constituted by cobalt HSs, with random orientations the CV state is preserved.

Different strategies have been employed to provide adequate nutrients for engineered living tissues. These have mainly revolved around providing oxygen to alleviate the effects of chronic hypoxia or anoxia that result in necrosis or weak neovascularization, leading to failure of artificial tissue implants and hence poor clinical outcome. While different biomaterials have been used as oxygen generators for in vitro as well as in vivo applications, certain problems have hampered their wide application. Among these are the generation and the rate at which oxygen is produced together with the production of the reaction intermediates in the form of reactive oxygen species (ROS). Both these factors can be detrimental for cell survival and can severely affect the outcome of such studies. Here we present calcium peroxide (CPO) encapsulated in polycaprolactone as oxygen releasing microparticles (OMPs). While CPO releases oxygen upon hydrolysis, PCL encapsulation ensures that hydrolysis takes place slowly, thereby sustaining prolonged release of oxygen without the stress the bulk release can endow on the encapsulated cells. We used gelatin methacryloyl (GelMA) hydrogels containing these OMPs to stimulate survival and proliferation of encapsulated skeletal myoblasts and optimized the OMP concentration for sustained oxygen delivery over more than a week. The oxygen releasing and delivery platform described in this study opens up opportunities for cell-based therapeutic approaches to treat diseases resulting from ischemic conditions and enhance survival of implants under severe hypoxic conditions for successful clinical translation.

Molybdates are biocidal materials that can be useful in coating surfaces that are susceptible to contamination and the spread of microorganisms. The aim of this work was to investigate the effects of copper doping of hydrated cobalt molybdate, synthesized by the co-precipitation method, on its antibacterial activity and to elucidate the structural and morphological changes caused by the dopant in the material. The synthesized materials were characterized by PXRD, Fourier Transformed Infrared (FTIR), thermogravimetric analysis/differential scanning calorimetry (TG/DSC), and SEM-Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial response of the materials was verified using the Minimum Inhibitory Concentration (MIC) employing the broth microdilution method. The size of the CoMoO4·1.03H2O microparticles gradually increased as the percentage of copper increased, decreasing the energy that is needed to promote the transition from the hydrated to the beta phase and changing the color of material. CoMoO4·1.03H2O obtained better bactericidal performance against the tested strains of Staphylococcus aureus (gram-positive) than Escherichia coli (gram- negative). However, an interesting point was that the use of copper as a doping agent for hydrated cobalt molybdate caused an increase of MIC value in the presence of E. coli and S. aureus strains. The study demonstrates the need for caution in the use of copper as a doping material in biocidal matrices, such as cobalt molybdate.

Since their inception in larger pond systems, the focus of anaerobic ponds has shifted from solids removal to optimising biogas production and reducing physical footprint to minimise land requirements. In this study, a horizontally baffled (HBAP) and vertically baffled (VBAP) anaerobic pond were compared. Distinct differences in the removal efficiency of COD fractions were observed, with particulate COD removal of 78% and 32%, and soluble COD removal of −26% and 19% in the HBAP and VBAP, respectively. A staged pond (SAP) was constructed through an HBAP placed upstream of a VBAP, with an additional HBAP used as a control (CAP). The SAP demonstrated superior biogas recovery potential over the control: methane production by the conclusion of the study was 6.09 and 9.04 LCH4 m−3 wastewater treated for the CAP and SAP, respectively. Methanogenic activity in the ponds was higher closer to the outlet, and hydrogenotrophic methanogenesis dominated over acetoclastic pathways.

The empirical extended Bloch's law about the saturation magnetization behavior as a function of temperature was checked in nanoparticles of yttrium iron garnet doped with zinc, nickel and cobalt. The exponent values from fitting extended Bloch's law with experimental results vary from 1.42 to 9.68, and are different from these expected values; 9/2, 2, 3/2, 3 and 5/2. The discrepancy was associated to the existence of structural defects and moments with frustrated exchange interaction, due to the nanoparticles size and thermal treatment conditions. Other adjustment attempt was performed with a linear term combined to the traditional Bloch's law T3/2 motivated by the nanometric particles size. This other attempt was unsuccessful showing discrepancy with the experimental results and attributed to the atomic disorder and magnetic frustrations.

The Arc (anoxic redox control) two-component system of Escherichia coli, comprising ArcA as the response regulator and ArcB as the sensor histidine kinase, modulates the expression of numerous genes in response to respiratory growth conditions. Under reducing growth conditions, ArcB autophosphorylates at the expense of ATP, and transphosphorylates ArcA via a His(292) → Asp(576) → His(717) → Asp(54) phosphorelay, whereas under oxidizing growth conditions, ArcB catalyzes the dephosphorylation of ArcA-P by a reverse Asp(54) → His(717) → Asp(576) → P(i) phosphorelay. However, the exact phosphoryl group transfer routes and the molecular mechanisms determining their directions are unclear. Here, we show that, during signal propagation, the His(292) → Asp(576) and Asp(576) → His(717) phosphoryl group transfers within ArcB dimers occur intra- and intermolecularly, respectively. Moreover, we report that, during signal decay, the phosphoryl group transfer from His(717) to Asp(576) takes place intramolecularly. In conclusion, we present a mechanism that dictates the direction of the phosphoryl group transfer within ArcB dimers and that enables the discrimination of the kinase and phosphatase activities of ArcB.

In this work, we have synthesized and characterized yttrium iron garnet nanoparticles doped with cobalt. The X-ray diffraction data showed a single phase, belonging to the cubic structure of Y3Fe5O12. Rietveld refinement revealed variation of the angles and interionic distances (Fe3+(a)-O2-Y3+(c) and Fe3+(d)-O2--Y3+(c) when Fe3+ ions are replaced by Co3+ ions in the tetrahedral (d) and octahedral (a) sites of YIG. In addition, the lattice parameter a, decreases from 12.3846 A to 12.3830 A with the increasing of cobalt concentration. The analysis by Infrared and Raman spectroscopies has shown a slight stretching at lower wave numbers as the dopant concentration increased. The magnetic measurements confirm the substitution of Fe3+ by Co3+ in the a-sites and d-sites with the reduction of the saturation magnetization from 26.63 emu/g to 24.92 emu/g, for 0.000 ≤ y ≤ 0.030. Changes in the coercive field varying the dopant concentration were related to the particle size and pinning centers existence.

Planar arrangements of cobalt hollow-spheres were studied by means of micromagnetic simulation. The calculated coercivity values are in correspondence with the reported experimental data. Dipole energy effects are determinant and more significant if thickness decreases. We observed the formation of some vortex and onion configurations, solutions for individual hollow-sphere, even so there is predominance of non-homogeneous reversal. This confirms that solutions for individual spheres are not efficient in the analysis of arrays.

Using micromagnetic simulation we present an analysis about the effects of the microstructure on the angular dependence of coercivity and quadrature. The results return curves profiles that resemble experimental data already reported in the literature. We show that, there is an ambiguity in case of adopting the curve profile of the angular dependence of coercivity as the starting point to assume the predominant reversion mode. We conclude in this study that, to infer any reversal mechanisms always have to take into account the nanowires microstructure.

In this work, we have studied the structural and magnetic properties of yttrium iron garnet nanoparticles doped with copper obtained by sol gel method. The lattice parameter decreases from 12.3779 A to 12.3774 A, for low doping and increases from 12.3788 A to 12.3814 A for high copper concentrations. The variation in the crystallite size was related with defects and internal stress produced by the dopant addition. The micrographs showed a similar format, rounded irregular form and lengthened, for all samples. Saturation magnetization (Ms) confirmed the substitution of Fe/Cu in the octahedral sites of YIG. Ms increased from 24.04 emu/g to 29.49 emu/g for dopant concentration varying from 0.00 to 0.01. For y = 0.03 the Ms = 26.05 emu/g and for y = 0.05, Ms = 26.35 emu/g. Changes in the coercivity (Hc) values are attributed to the pinning centers existence and particle format.

In this work, we investigated the effect of Y3+ inclusion in ZnO nanoparticles doped with Fe3+ synthesized by the sol gel method. Transmission Electron Microscopy (TEM) images showed agglomerated nanostructures with different shapes and average particle size distributions ranging from 6 nm to 44 nm in diameter. Electron Paramagnetic Resonance (EPR) studies of the Zn0.98−yY0.02FeyO ( y = 0.00 , 0.02, 0.03 and 0.04) were carried out using X band (9.7 GHz) at room temperature. For undoped ZnO and doped with Y3+, complex line shapes were observed as a result of oxygen vacancies (VO+1). In addition, the Y3+ inclusion provokes an enhancement of the linewidth and the resonance field due to intrinsic defects in the hexagonal structure. This observation is compatible with a shortest relaxation time by reason of the particle size reduction and an extra antiferromagnetic local field as a result of the Y3+ presence. For co-doped ZnO samples, the EPR spectra confirms the presence of Fe3+ and Y3+ at the core Zn sites, altering the lattice strain of the ZnO structure. This result was monitored by the zero-field splitting (ZFS) parameters of the spin Hamiltonian, corroborating a reduction in the Fe - Fe interaction. The presence of Y ions was also confirmed in interstitial sites, resulting in a small g -shift from 4.2 to 4.0 associated with modifications of the rhombic component, E, of the Spin–Hamiltonian. This study contributes to the understanding of structural defects caused by the Y and Fe inclusion in the Wurtzite crystal structure of ZnO, a material with potential applications in spintronic devices.

Ibuprofen (IBU) is one of the most-sold anti-inflammatory drugs in the world, and its residues can reach aquatic systems, causing serious health and environmental problems. Strategies are used to improve the photocatalytic activity of zinc oxide (ZnO), and thosethat involvethe inclusion of metalhave received special attention. The aim of this work was to investigate the influence of the parameters and toxicity of a photoproduct using zinc oxide that contains cerium (ZnO-Ce) for the photodegradation of ibuprofen. The parameters include the influence of the photocatalyst concentration (0.5, 0.5, and 1.5 g L−1) as well as the effects of pH (3, 7, and 10), the effect of H2O2, and radical scavengers. The photocatalyst was characterized by Scanning Electron Microscopy-Energy Dispersive Spectroscopy, Transmission electron microscopy, Raman, X-Ray Diffraction, surface area, and diffuse reflectance. The photocatalytic activity of ibuprofen was evaluated in an aqueous solution under UV light for 120 min. The structural characterization by XRD and SEM elucidated the fact that the nanoparticle ZnO contained cerium. The band gap value was 3.31 eV. The best experimental conditions for the photodegradation of IBU were 60% obtained in an acidic condition using 0.50 g L−1 of ZnO-Ce in a solution of 20 ppm of IBU. The presence of hydrogen peroxide favored the photocatalysis process. ZnO-Ce exhibited good IBU degradation activity even after three photocatalytic cycles under UV light. The hole plays akey role in the degradation process of ibuprofen. The toxicity of photolyzed products was monitored against Artemia salina (bioindicator) and did not generate toxic metabolites. Therefore, this work provides a strategic design to improve ZnO-Ce photocatalysts for environmental remediation.

Nanostructured Ni(OH)2 is a promising candidate to be used as an extrinsic pseudocapacitors material. Here, nickel hydroxide (Ni(OH)2) was grown on the surface of a Ti plate, galvanostatically via electrodeposition method. In the electrodeposited films a stable α-Ni(OH)2 phase with particles in cabbage form and average crystallite size of 20 nm is obtained. The α-Ni(OH)2 sample exhibits excellent electrochemical performance at different current densities and good cycling stability. A maximum specific capacitance of 1903 F g−1 is achieved at a current density of 1 mA cm−2. The energy and power density values found are 42.31 W h kg−1 and 430 W kg−1.

Zn-doped YIG was prepared using the sol–gel method with TGA measurements showing the phase formation between 900 and 1000 °C. XRD analysis showed close to 1100 °C the formation of Franklinite phase, coexisting with the cubic YIG. Y3(Fe1–xZnx)5O12 samples with different Zn concentrations (x = 0, 0.01, 0.03, and 0.05) were prepared and analyzed for a magnetic study. A decrease in magnetic moment of the samples was confirmed on increasing the concentration of Zn ions. This decrease is due to the substitution of Fe ions by Zn. This also confirmed the results of XRD showing the linear increase in the lattice parameter. Fittings by Bloch's law shows results compared with those already reported in the literature. The exponent and constant for the Bloch law presented similar values to those reported for YIG doped with other ions. We obtained the parameter α ∼10−6 K−n with n close to 1.9 for all samples.

In this work, we present a study about the preferential site occupancy of Ni ions and the oxidation state of Fe ions in the yttrium iron garnet (YIG) crystal structure of nanoparticles obtained by sol-gel method. Transmission electron microscopy (TEM) showed particles and clusters with irregular shapes. Selected area electron diffraction (SAED) showed bright spots and diffuse rings characteristic of well-defined crystals supporting the presence of fine particles. The distribution of Ni and Fe ions in the tetrahedral (d) and octahedral (a) sites of YIG structure has been revealed by the Mossbauer spectroscopy. The Electron paramagnetic resonance (EPR) results confirmed the inclusion of Ni in the Fe sites and an increase in the g factor for the doped YIG sample. X-ray Photoelectron Spectroscopy (XPS) has been employed to check the valence states, confirming that Y, Ni and Fe are predominantly in the Y3+, Ni2+, Fe3+ and Fe2+ oxidation states. This paper contributes to the understanding of preferential site occupancy of Ni in the yttrium iron garnet; a compound with few studies and high importance in spintronics applications.

In the present work, results about the effects of the length distribution in hexagonal arrays of nine nickel nanowires were obtained by micromagnetic simulation. Arrangements with average nanowires length of 500 nm and different length dispersion (σ = 0, 15, 62.49, 92.47 nm) were simulated. The effects of the length distribution on magnetization curves are not relevant and the angular dependence of the remanence and coercivity does not present significant variations. Despite that, for the reversal process, there are variations as the σ value increases. Moment configuration maps showed important information for the reversion, suggesting that hysteresis curves are not sufficient in arrays of nine nickel nanowires.

The effects of sodium chloride (NaCl) or sodium hydroxide (NaOH) used to control the p-type conductivity of cuprous oxide Cu2O thin films by reactive thermal annealing (ReTA) at 550 °C in low oxygen content applied to NaX/Cu2O (X = Cl or OH) bilayers were studied. NaX nanolayers were deposited by dipping the Cu2O films in their saturated solutions. It has been reported that annealing Cu2O films covered with NaCl powders increased their hole concentration, but the effects of the X− ions on the oxide film had not been clarified. Here we report that the ReTA process applied to NaX/Cu2O bilayers reduces the electrical resistivity and increases the hole mobility, but the surface characteristics were also modified. During the ReTA process, CuXn (n = 1, 2) chemically reactive compounds are produced etching the film surface. The resistivity of the films was reduced by a factor of ten with respect to the as-grown Cu2O films by the Na incorporation and the hole mobility increased by the surface passivation due to the CuXn surfactant compounds produced during the ReTA process. The ReTA process applied during short periods the Cu2O phase was also stabilized according to the experimental results.

Background 25 (OH) D is a steroid prohormone that participates in calcium homeostasis and bone health.1 Nonclassical functions of this vitamin have been described in a variety of cells of the innate and adaptive immune system. Currently, the immunomodulatory role of 25 (OH) D in Systemic Lupus Erythematosus (SLE) continues in debate. In addition, a correlation between non-optimal levels of 25 (OH) D and disease activity has been observed.2 In the SLE, there is a high prevalence of non-optimal levels of vitamin D. A prevalence of 25 (OH) D insufficiency of 15% to 75% is reported.3 Objectives To determine the relationship between vitamin D levels and disease activity in SLE. Methods It is a prospective, cross-sectional study, in all patients who attended the rheumatology clinic of the Hospital Docente Padre Billini in the period August – October 2017, where the levels of vitamin D and activity of the disease were measured with SELENA-SLEDAI (≤3 without activity, 3–12 moderate activity,≥12 high activity). Vitamin D deficiency is defined as serum levels of 25 (OH) D Results 45 patients who met criteria SLE SLICC 2012 were included. 97.7% (44) were women. The most frequent age range was 31–45 years. 24.4% (11) had decreased calcium values. The vitamin D values were insufficient in 77.7% (35) of the patients and deficient in 4.4% (2) According to SELENA-SLEDAI, 77.7% (35) had no activity of the disease, 20% (9) had moderate activity and 2.2% (1) had high activity. Of the patients who reported disease activity, only 13.3%6 had insufficient vitamin D. There is no significant difference between patients who have vitamin D values greater than or less than 20 ng/ml. In both groups, the majority had SELENA-SLEDAI in low activity. Conclusions The vitamin D levels were not associated with an increase in disease activity in our study patients. Although our country is an island, the use of sunscreen and avoid sunbathing is something common, it causes to find low levels of vitamin D, not only in patients with SLE, where avoiding sunbathing is a recommendation, but also in other pathologies that come to our service. We believe that vitamin D levels should be measured in the general population, to have a reference range and study their influence on health. References [1] Christakos S, Dhawan P, Verstuyf A, Verlinden L, Carmeliet G. Vitamin D: Metabolism, Molecular Mechanism of Action, and Pleiotropic Effects. Physiol Rev. 2016; 96:365–408 [2] Mandal M, Tripathy R, Panda AK, et al. Vitamin D levels in Indian systemic lupus erythematosus patients: association with disease activity index and interferon alpha. Arthritis Res Ther. 2014;16: R49. [3] Hamza RT, Awwad KS, Ali MK, Hamed AI. Reduced serum concentrations of 25-hydroxy vitamin D in Egyptian patients with systemic lupus erythematosus: relation to disease activity. Med Sci Monit. 2011;17:CR711–8. Disclosure of Interest None declared

Porous silicon films obtained by the metal-assisted vapor-chemical etching technique have been characterized. For the film formation, epitaxial (100) N/P+, 1–5 Ω cm monocrystalline silicon wafers were used. The vapors of an alcoholic solution of H2O2/HF were drawn towards the silicon surface, which was previously covered with a thin layer of gold (~8 nm) for the catalytic etching. For the optical and morphological characterization of porous films, Raman spectroscopy, Ellipsometry, FTIR spectroscopy and SEM images were used. The films thickness kept a linear relationship with etching time. A porosity gradient from the surface towards the interface (65% to 12%) was observed in the films. A large amount of Si–H bonds as related to O–Si–O bonds were observed and the pore size depends on the HF concentration. Irregular morphology was found in films formed with 50% HF.

In this work we present the fabrication of yttrium iron garnet (YIG) films with low magnetic damping on silicon (100) substrate. We show in addition that the sol–gel method is a technique that allows the obtaining of YIG films with good quality. The study by X-ray diffraction (DRX) showed characteristic reflections of the cubic YIG phase as well as a very small reflection typical of the orthorhombic phase. The surface of the film was investigated by scanning electron microscopy (SEM) and showed the formation of very small regular pores. The ferromagnetic resonance measurement shows a good result with a low linewidth value of 53 Oe. Our result here is the lowest value found in the literature for YIG film on silicon substrate. Our result is very important for spintronic experiments because these films obtained by sol–gel are thicker than the same films fabricated by the sputtering and other method.

In this work, we show a simple way to functionalize tungsten oxide nanowires (WO3-NWs) using a saturated palladium chloride (PdCl2) solution deposited by a drop-casting method. WO3-NWs were synthesized by close-spaced chemical vapor deposition (CSVT). The morphological and structural characterizations showed that the diameters of WO3-NWs are in the range from 50 to 200 nm with lengths above 10 μm, and correspond to the orthorhombic phase of WO3, respectively. The sensor was fabricated using the WO3-NWs and tested with hydrogen and volatile organic compounds (VCO's). A comparative study was done on the sensing performance, before and after the Palladium functionalization of the WO3-NWs, considering a wide range of gas concentrations and moderate operating temperatures (100–400 °C). The results show that this simple functionalization process significantly increases the sensor sensitivity and reduces the time constants. In addition, it has been shown that at 300 °C the decorated sensor becomes more selective to hydrogen and xylene for all concentrations considered in this research. Finally, the mechanisms involved in improving the gas sensing properties of WO3-NWs functionalized with Palladium are discussed.

Boron silicon oxycarbide fiber mats have been obtained through pyrolysis in inert atmosphere of sol–gel derived hybrid materials. The characterization of the preceramic hybrid fibers and the pyrolysis process reveals different boron incorporation depending on the composition. The ceramic conversion involves a series of reactions governed by the presence of the mixed bonds that implies larger phase segregation and higher graphite nanodomain size with the decrease of the number of borosiloxane bridges in the preceramic material. The formation of a mixed structure, where both Si and B are taking part on the ceramic network occurs with the excess of B that precipitates as boric acid in the surface of the fibers. These precipitates can cause pores in the surface of the pyrolyzed fiber.

The paper presents the transformation of photoluminescence (PL) spectra of nonconjugated and bioconjugated core/shell CdSe/ZnS QDs covered by PEG polymer at the aging in ambient air. Studied QDs are characterized by the sizes: (i) 3.6–4.0 nm and color emission with the maxima at 560–565 nm (2.19–2.25 eV) and (ii) 5.2–5.3 nm and with emission at 605–610 nm (2.02–2.08 eV). The part of 565 nm CdSe/ZnS QDs has been bioconjugated to the mouse anti PSA (Prostate-Specific Antigen) antibodies and the part of 605 nm QDs has been bioconjugated to the antihuman IL10 (Interleukin 10) antibodies using the commercially available 565 nm and 605 nm QD conjugation kits. It is revealed that the aging process in ambient air has the very strong impact on PL spectra of nonconjugated core/shell CdSe/ZnS QDs covered with PEG polymer. The aging process relates to the polymer modification in ambient air that is accompanied by the three effects: (i) polymer transparency increasing for the emission of CdSe cores (2.03 or 2.20 eV), (ii) the intensity stimulation of high energy PL bands (2.37, 2.73 and 3.06 eV) related to the interface states at the ZnS/PEG polymer interface and (iii) the elastic strain modification in QD systems. The concentration of interface states at the ZnS/polymer interface increases at the aging of PEG polymer in ambient air.

We present the electrical and structural characterization of Al x Ga 1− x As layers grown in a metallic-arsenic-based-MOCVD system. The gallium and aluminium precursors were the metal-organic compounds trimethylgallium (TMGa) and trimethylaluminium (TMAl), respectively. Al x Ga 1− x As layers that were grown at temperatures less than 750 °C present a high electrical resistivity. Independent of the used III/V ratio the samples that were grown at temperatures greater that 750 °C were n -type with an electron concentration of around 10 17 cm −3 and a carrier mobility of 2200 cm 2 /V-s. Chemical composition studies by SIMS exhibit the presence of silicon, carbon and oxygen as the main residual impurities. Silicon concentration of around of 10 17 cm −3 is very close to the free carrier concentration determined by the Hall-van der Pauw measurements. Composition homogeneity and structural quality are demonstrated by Raman measurements. As the growth temperature is increased the layers compensation decreases but the Raman spectra show that the crystalline quality of the layers diminishes.

Ohmic contacts with a palladium (Pd) diffusion barrier were formed on GaAs substrates. The metal-contact structure consists of a gold-based-alloy/Pd/semiconductor-substrate. Characteristics of the deposited Pd films by “electroless” deposition on semiconductor-substrates are reported. SIMS analysis realized on the metal-semiconductor structures demonstrates the capability of the Pd films to act as a diffusion barrier. Contact resistance of the ohmic contacts was measured by the transmission line method (TLM).

Research published on bioreactors discusses the importance of integrating reactor kinetics and mixing as the basis for understanding process hydrodynamics and developing sound design procedures. Nonetheless, many studies are focused on either kinetics or mixing, but studies on the integration of both are seldom found in the literature. Despite the availability of several mixing models (e.g., completely stirred tank reactor, plug flow, dispersion model, completely mixed tanks in series model, and the compartments model), there is an intrinsic complexity in studying process kinetics and reactor hydrodynamics experimentally. In this sense, this work reports the results of a 6-month study for three pilot-scale anaerobic ponds (APs); of which, two had modified physical configurations (one with a mixing chamber, the other with horizontal baffles) and the third was a conventional AP run as a control unit. They were evaluated under three different hydraulic loading rates. The AP provided with the mixing ...

The photoluminescence (PL) of nonconjugated and bioconjugated core-shell CdSe/ZnS quantum dots (QDs) has been discussed in this paper. Commercial CdSe/ZnS QDs with the size of 3.6-4.0 nm covered by polymer with emission at 560-565 nm (2.19-2.22 eV) have been used. The QD bioconjugation is performed with the mouse anti PSA (Prostate-Specific Antigen) antibody (mab). PL spectra of nonconjugated QDs are characterized by a superposition of PL bands related to exciton emission in the CdSe core (2.19-2.22 eV) and to hot electron-hole emission via surface states (2.37, 2.73 and 3.06 eV) at the CdSe/ZnS or ZnS/polymer interfaces. The PL spectrum of bioconjugated QDs has changed dramatically, with essential decreasing of the hot electron-hole recombination flow via interface states. This effect is explained on the base of re-charging of QD interface states at the bioconjugation. It is shown that the CdSe/ZnS QDs with interface states are very promising for the study of bioconjugation effects to antibodies (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Combining the sol gel method and spin coating technique, yttrium iron garnet (YIG) films were obtained on silicon (Si) substrate. Four YIG films with different thicknesses were fabricated to achieve low FMR linewidth. The x-ray diffraction has shown a single phase, belonging to the cubic structure of the YIG, while the morphology of the films has presented small pores and some grains on the surface. The FMR linewidth of the YIG films decreased 110 Oe, 108 Oe, 93 Oe and 71 Oe as the film thickness increased 134 nm, 246 nm, 376 nm and 489 nm, respectively. This result indicates that high-quality YIG films can be achieved on Si substrates, controlling the thickness. The sol gel method is shown as a very economical and easy alternative to obtain YIG films with low FMR linewidth, which may be important for making microwave integrated devices.

It is not easy, in general, to improve the mechanical properties of aluminium alloys by traditional nitriding methods. By contrast, plasma immersion ion implantation (PIII) has been successfully used for hardening and in wear resistance improvement. The present work sets out to investigate the formation of AlN on 6061T6 aluminium samples by the PIII process at low energy (2–6 keV) with ion doses in the order of 1018 ions/cm2 and from nitrogen–argon mixtures at different concentrations (N70–Ar30, N50–Ar50 and N30–Ar70) maintained at ∼400 °C sample temperatures. The outcome was evaluated by X-ray diffractometry, scanning electron microscopy, Vickers microhardness tests and profilometry.

Grape pomace is the main by-product from the wine industry. It is principally made up of grape skin and seeds. Drying this by-product is the first step for the later extraction of components with high added value like oil or antioxidants. Due to the different characteristics of the components, the study of the drying kinetics of grape pomace must be addressed taking its components into account one by one. For that purpose, grape seeds from the Spanish wine industry were dehydrated in a convective laboratory dryer at 70 °C and at 1, 2 and 3 m/s until a weight loss of 40% was reached. Drying kinetics was determined in triplicate. Modelling was carried out by means of a diffusion model without considering shrinkage and external resistance. Grape seeds were assumed to be spherical. For all the fits, the explained variance was higher than 96.9 % and the mean relative modulus was lower than 1.7 %. Between 1 and 2 m/s, effective diffusivity increased in line with air velocity, although the values of effective diffusivity calculated for 2 and 3 m/s were similar. It seems to indicate that for the experimental conditions under study, the external resistance is not negligible at 1 and 2 m/s and for higher air velocities the internal resistance to mass transfer controls the drying process. These results coincide with those found by other authors when studying different food products.

Samples of pure titanium have been treated by means a plasma immersed ion implantation (PIII) process in a DC glow discharge in pure oxygen and in different nitrogen-oxygen mixtures. In contrast with conventional voltage supply based glow PIII, the present study has been conducted with a novel specifically designed high current supply which allows a high electron density to be kept constant, regardless of gas pressure variations, within the operational ranks. Thus, the acquired sample characteristics can be more clearly ascribed to the chemical composition of the mixture. One stratified TiO2 (rutile) and TiN0.26 layer was identified from XRD and Raman spectroscopy, both of these compounds reputedly being highly biocompatible. The superficial hardness of the samples was improved up to more than five times that of the untreated reference sample, namely, ∼1600 Vickers microhardness (10 g load) thanks to a 2–6 μm deep implanted layer. These optimal results have been obtained from an 80% nitrogen 20% oxygen mixture at 1×10-2 torr. Furthermore, with this gas proportion, the best roughness finishing of the sample set was accomplished, which can be relevant for biocompatible applications.

This work presents the optical and structural characterization of p-type GaAs epilayers. The gallium precursor was the organometallic compound trimethylgallium (TMG). The influence of the doping in the optical and structural properties of the GaAs layers has been studied by photoluminescence (PL) and Raman dispersion measurements. The range of analyzed hole concentration was from 1017 to 1019 cm-3 as measured by the Hall-van der Pauw method. For carrying out doping p-type, it was necessary to modify the hydrogen activity in the growth atmosphere with the control of a H2+N2 mixture, which was used like transporting gas. The photoluminescence response and Raman dispersion of the layers are strongly dependence of the growth temperature, which were investigated based on the hole concentration. The PL response of the layers shows two radiative transitions, band-to-band and band-to-C-acceptor at low hole concentration and disappears at high concentrations. Raman scattering spectra show LO mode at 270 cm-1 for low doped samples and a LO-like mode at 290 cm-1 produced by the phonon-holeplasmon coupling for high doped samples.

Thin polycrystalline ZnO films were grown on silicon substrates by dc reactive magnetron sputtering using zinc oxide targets. The quality of the ZnO layers was assessed by X-ray diffraction (XRD), atomic force microscopy, Raman scattering, and photoluminescence measurements. The XRD studies and Raman studies revealed that the ZnO films crystallize in the wurtzite structure. Room temperature photoluminescence spectra consisted of a narrow near-band-edge ultraviolet band and a broad defect-related green band with peak positions at 380 and 516 nm, respectively. The main goal of the work was to define the growth conditions to prepare zinc oxide films with adequate properties to be used in electroluminescent devices. The films exhibited the best surface appearance with a 40:1 argon/oxygen flow rate, a total pressure of 1.5×10−3 mbar, and a substrate temperature of 230 °C. The structural and luminescence properties improved noticeably with the thermal annealing processes at 800 °C for 1 h.

Hybrid materials have been obtained using a given concentration of tetraethylorthosilicate (TEOS) and polydimethylsiloxane (PDMS). Different size and shape monolithic samples have been achieved by using containers of both different evaporation areas and heights. The hybrid materials have been pyrolyzed under nitrogen atmosphere to yield porous silicon oxycarbide glasses, consisting of interconnected spherical particles and a continuous open-pore channel. The texture of the glasses shows a gradient particle size distribution (PtSD) from the top (2.88 μm) to the bottom (7.83 μm) of the samples. This gradient in the particle size leads also to a gradient distribution of porosities in the oxycarbide glasses. Thus, pore sizes increases from 6 μm at the top evaporation face to 13 μm at the bottom of the samples, and porosities in the corresponding regions decrease from 77% to 63%, respectively. The gradient distribution has been assigned to a gradient concentration of PDMS in the hybrid preceramic material as determined by the elemental analysis. The carbon concentration (free and covalently bonded carbon) in the hybrid materials increases with the sample thickness or height. However, the lower concentration of PDMS molecules found at the bottom of the hybrid samples leads, after pyrolysis, to higher values of retained carbon and pore sizes in the SiOC glasses. An interesting finding is that the gradient PDMS distribution also provokes a gradient nanodomain size of the segregated free carbon as a form of graphite, typical in SiOC glasses.

We have tested the hypothesis that alterations in length dependent activation (LDA) of cardiac myofilaments represent an important regulatory mechanism affecting the Frank-Starling mechanism as determined by the slope (E(es)) of the relation between left ventricular (LV) volume and end-systolic pressure. We employed a transgenic (TG) mouse model in which the cardiac isoform of TnI (cTnI) has been completely replaced with slow skeletal TnI (ssTnI), the embryonic/neonatal isoform in the heart. Compared to non-transgenic (NTG) controls, myofilaments from TG-ssTnI hearts demonstrate an increase in Ca(2+) sensitivity and a substantially blunted LDA that is unaffected by PKA-dependent phosphorylation. We measured in situ LV pressure and volume relations during basal conditions and isoproterenol (ISO) stimulation. In the basal state in TG-ssTnI hearts there was significant increase in end-systolic pressure and slight decrease in heart rate. ISO stimulation resulted in a significant increase in heart rate, ejection fraction, maximum dP/dt, preload-recruitable stroke work, maximum dP/dt versus end diastolic volume and cardiac output in both groups. During basal conditions there was no difference in the E(es) relation between NTG and TG-ssTnI groups. However, during ISO stimulation the E(es) relation was significantly different between NTG and TG-ssTnI groups. Our study provides the first direct evidence that enhancement in differences in LDA between cardiac myofilaments from NTG and TG-ssTnI hearts induced by post-translational modifications of sarcomeric proteins are reflected in the in situ beating heart by a different change in E(es). Thus, changes in LDA should be considered in interpreting results from in situ experiments on inotropic effects associated with physiological and patho-physiological states of the heart.

NaBH 4 , a safe and high energy density source of H 2 for fuel cells, requires a catalyst for reliable hydrogen production. In this paper we show that Pt and Pd atoms, apparently dispersed elementally, on functionalized surfaces of carbon nanotubes (CNT) leads to the highest value for the figure of merit ( ~ 300 L min − 1 g metal − 1 [NaBH 4 ] −1 ) reported so far in the literature. This result was achieved with a 150 μm thick CNT paper. Thinner paper produces even higher rates of hydrogen generation. The catalyst is robust, continuing to operate without degradation in performance for more than 20 cycles. The kinetic data are analyzed by a combination of first order and zero order reactions. The analysis provides a framework for predicting the performance of the catalyst for fuel cell applications.

The effects of storage time and temperature on blood alcohol concentration were evaluated in this two-part study involving 34 ethanol-negative and 21 ethanol-positive volunteers. Multiple 10-mL Vacutainer(®) blood tubes containing 100 mg of sodium fluoride and 20 mg of potassium oxalate were collected from living persons and subjected to various storage conditions. The time from collection to analysis ranged from 0 to 60 days and storage temperatures ranged from 3 to 20°C. Regardless of the storage conditions, all ethanol-negative samples remained negative (

In meat brining, the concentration of brine could affect both water and NaCl transport and, consequently, the total length of the treatment and the final quality of the product. In the present work, the kinetics of water and NaCl transport during the brining of pork loin slices in different brine concentrations (50, 100, 150, 200, 240 and 280 kg/m3) were determined (5±1 °C). In the case of moisture content, the brine concentrations of under 200 kg/m3 led to significant (p < 0.05) sample hydration. Close to this concentration, no net water transport took place, and above it, samples were dehydrated. As regards the evolution of NaCl content, the higher the concentration of brine used, the greater the NaCl content in the sample. The identified effective moisture diffusivity showed a tendency to decrease when the brine concentration rose, changing from positive (hydration) to negative values (dehydration). For NaCl, the identified effective diffusivity remained constant with brine concentration (1.90±0.28) 10–10 m2/s.

The hydrolysis and condensation reactions of γ-APS have been studied in different acid content aqueous solution by using Fourier Transform infrared (FT-IR) spectroscopy. The hydrolysis of γ-APS under the studied conditions can be followed by the increase of the ethanol band located at 882 cm−1 and the decrease of the band due to the ρ(CH3) of γ-APS molecules located at 959 cm−1. Hydrolysis reaction is faster by increasing both H2O and acid concentrations, and it is completed when 3 moles of H2O per mole of γ-APS are used. The increase of the vibrational band located at 1146 cm−1 shows that condensation of the hydrolysed γ-APS molecules take place forming linear chains in poorly cross-linked structures. Besides, both 8-membered cyclic siloxane formations and poorly cross-linked structures are formed and increase as the water and acid content are increased. On the other hand, highly connected cross-linked structures do not appear due to the steric hindrance of the non-hydrolysable aminopropyl group. The silanol band shows that hydrolysis is faster than condensation except for samples with the lowest H2O content.

Dielectric barrier discharge cells (DBDCs) have proved their efficiency in the generation of cold plasmas for hazardous organic compound degradation. Here, we describe the design and construction of a dual thermal packed-bed reactor and DBDC-based system to carry out the degradation of hazardous organic compounds in both liquid and gas phases. The main components of this system are: (i) the thermal treatment system, (ii) DBDC and (iii) resonant inverters of low (3.3 kHz) and high (100 kHz) calculated frequencies. The definition of the cell physical parameters considers: (a) a first-order degradation ratio of the compound and (b) the air breakdown at atmospheric pressure as a function of the transport carrier gas. The power consumed by the cells during the discharges was computed theoretically and experimentally. Using the dual system along with a gas chromatography diagnostic system, highly efficient degradations of a test compound (benzene) have been obtained, reaching 99.950% in the case of a cell experimentally operated at 3.3 kHz and up to 99.996% in another one at 94.3 kHz. An additional 3.7 times reduction in the latter case residence time with respect to the low frequency cell has been found.

Photoluminescence and Raman scattering investigations were performed on porous silicon (PSi) films prepared using different electrochemical etching regimes with the aim of obtaining PSi layers with a variation of Si nanocrystallite sizes. Then Schottky barriers were formed using aluminium contact on a porous surface. Schottky diodes were completed by adding aluminium ohmic contacts to the rear side of the p-type silicon substrate. Current voltage characteristics of the Schottky barriers have been investigated in the dark and under light exposition and photocurrent spectra have been obtained. It is shown that some optimal electrochemical etching regime exists (at etching current density of 5 mA/cm 2 ) which allows the preparation of PSi with a small density of surface defects and best diode parameters. Moreover, our results show that it is possible to change the photocurrent spectrum of Schottky diodes based on PSi by the variation of Si nanocrystallite sizes.

The influence of the concentration of triethylborate (TEB) on the surface properties of hybrid materials prepared from tetraethylortosilicate (TEOS) and polydimethylsiloxane (PDMS) has been studied. TEB concentration has been varied between 0 and 30 wt.% respect to the total amount of alkoxyde whereas PDMS concentration has been set at 40 wt.% in all the hybrid samples. Pore size distributions (PSDs), specific surface areas (SSAs) and surface energies have been determined for such materials. PSDs have shown that pore size and pore volume increase with the amount of TEB forming the hybrid, whereas SSAs decrease. Surface energies have been determined by inverse gas chromatography at infinite dilution (IGC-ID) and have been divided into dispersive and specific surface energies. It was also found that TEB affects to both, dispersive and specific surface energies. Dispersive surface energy values increase from 23.23 mJ⋅m−2 for the pure TEOS-PDMS hybrid sample to 31.07 mJ⋅m−2 for the 30wt.% TEB-containing material. This increase has been attributed to the enhanced polarizability of the TEOS-PDMS hybrid when TEB is incorporated into the structure, a result which is consistent with the composition and structural characterization of the studied hybrid materials. Acid and base (kA, kB) surface constants also evidence a correlation with the TEB concentration: kA decreases and kB increases with the increase of TEB in these hybrids, a result which has been assigned to the lower acidity of boranol groups respect to that of silanols. The formation of an hybrid structure of Si–O–Si(PDMS) and B–O–Si(PDMS) bonds has been confirmed by FT-IR spectroscopy by the presence of a band at 850 cm−1 and a shoulder between 930 and 880 cm−1, respectively.

The sol–gel method was used to prepare four different silicon–boron containing gels to obtain monolithic Ormoborosil (organically modified borosilicate) materials. These Ormoborosils were treated under flowing nitrogen at different temperatures from 200 to 1100 °C to produce mixed vitreous oxycarbides of silicon and boron. Fourier transform-infrared spectroscopy (FT-IR) was used to study the structural changes that take place at every studied temperature. Results have shown that boron atoms are bonded preferentially to silicon atoms in the PDMS units. The increase of the boron content in the Ormoborosil network produces a decrease of the mineralisation temperature. Moreover, it has been observed that boron promotes the formation of oxycarbide structures and avoids the formation of a free carbon phase in the oxycarbide network.