Synergy of diffraction and spectroscopic techniques to unveil the crystal structure of antimonic acid.

The elusive crystal structure of the so-called 'antimonic acid' has been investigated by means of robust and state-of-the-art techniques. The synergic results of solid-state magic-angle spinning nuclear magnetic resonance spectroscopy and a combined Rietveld refinement from synchrotron X-ray and neutron powder diffraction data reveal that this compound contains two types of protons, in a pyrochlore-type structure of stoichiometric formula (H3O)1.20(7)H0.77(9)Sb2O6. Some protons belong to heavily delocalized H3O+ subunits, while some H+ are directly bonded to the oxygen atoms of the covalent framework of the pyrochlore structure, with O-H distances close to 1 Å. A proton diffusion mechanism is proposed relying on percolation pathways determined by bond-valence energy landscape analysis. X-ray absorption spectroscopy results corroborate the structural data around Sb5+ ions at short-range order. Thermogravimetric analysis and differential scanning calorimetry endorsed the conclusions on the water content within antimonic acid. Additional 0.7 water molecules per formula were assessed as moisture water by thermal analysis.

Identifying the presence of magnetite in an ensemble of iron-oxide nanoparticles: a comparative neutron diffraction study between bulk and nanoscale.

Scientific interest in iron-oxides and in particular magnetite has been renewed due to the broad scope of their fascinating properties, which are finding applications in electronics and biomedicine. Specifically, iron oxide nanoparticles (IONPs) are gathering attraction in biomedicine. Their cores are usually constituted by a mixture of maghemite and magnetite phases. In view of this, to fine-tune the properties of an ensemble of IONPs towards their applications, it is essential to enhance mass fabrication processes towards the production of monodisperse IONPs with controlled size, shape, and stoichiometry. We exploit the vacancy sensitivity of the Verwey transition to detect the presence of magnetite. Here we provide direct evidence for the Verwey transition in an ensemble of IONPs through neutron diffraction. This transition is observed as a variation in the Fe magnetic moment at octahedral sites and, in turn, gives rise to a change of the net magnetic moment. Finally, we show this variation as the microscopic ingredient driving the characteristic kink that hallmarks the Verwey transition in thermal variation of magnetization.

Topotactic Oxidation of Perovskites to Novel SrMo1-xMxO4-δ (M = Fe and Cr) Deficient Scheelite-Type Oxides.

New polycrystalline SrMo1-xMxO4-δ (M = Fe and Cr) scheelite oxides have been prepared by topotactical oxidation, by annealing in air at 500 °C, from precursor perovskites with the stoichiometry SrMo1-xMxO3-δ (M = Fe and Cr). An excellent reversibility between the oxidized Sr(Mo,M)O4-δ scheelite and the reduced Sr(Mo,M)O3-δ perovskite phase accounts for the excellent behavior of the latter as anode material in solid-oxide fuel cells. A characterization by X-ray powder diffraction (XRD) and neutron powder diffraction (NPD) has been carried out to determine the crystal structure features. The scheelite oxides are tetragonal, space group I41/a (No. 88). The Rietveld-refinement from NPD data at room temperature shows evidence of oxygen vacancies in the structure, due to the introduction of Fe3+/Cr4+ cations in the tetrahedrally-coordinated B sublattice, where Mo is hexavalent. A thermal analysis of the reduced perovskite (SrMo1-xMxO3-δ) in oxidizing conditions confirms the oxygen stoichiometry obtained by NPD data; the stability range of the doped oxides, below 400-450 °C, is lower than that for the parent SrMoO3 oxide. The presence of a Mo4+/Mo5+ mixed valence in the reduced SrMo1-xMxO3-δ perovskite oxides confers greater instability against oxidation compared with the parent oxide. Finally, an XPS study confirms the surface oxidation states of Mo, Fe, and Cr in the oxidized samples SrMo0.9Fe0.1O4-δ and SrMo0.8Cr0.2O4-δ.

A comprehensive examination of the local- and long-range structure of Sb6O13 pyrochlore oxide.

The crystal structure of the Sb6O13 oxide, exhibiting a defect pyrochlore crystal structure with atomic vacancies, has been studied using a complete set of state-of-the-art techniques. The degree of antimony disproportionation in Sb3+ and Sb5+ valence states has been directly determined around 36% and 64%, respectively, using X-ray absorption near edge structure (XANES). These findings are in excellent agreement with our Rietveld analysis of synchrotron X-ray (SXRD) and neutron powder diffraction (NPD) results. Moreover, the highly distorted Sb3+ coordination due to its lone electron pair has been critically revisited. The bonding distances and coordination of Sb3+ and Sb5+ species closely agree with an extensive dynamic and crystallographic determination using the Extended X-ray Absorption Fine Structure (EXAFS) technique. Most importantly, the specific local disorder of the two distinctive Sb ions has been crosschecked monitoring their unusual Debye-Waller factors.

Crystal Structure Features of CsPbBr3 Perovskite Prepared by Mechanochemical Synthesis.

We present a mechanochemical procedure, with solvent-free, green-chemistry credentials, to grow all-inorganic CsPbBr3 perovskite. The crystal structure of this perovskite and its correlations with the physicochemical properties have been studied. Synchrotron X-ray diffraction (SXRD) and neutron powder diffraction (NPD) allowed us to follow the crystallographic behavior from 4 to 773 K. Unreported features like the observed negative thermal expansion of the b unit-cell parameter stem from octahedral distortions in the 4-100 K temperature range. The mechanochemical synthesis was designed to reduce the impact energy during the milling process, leading to a defect-free, well-crystallized sample characterized by a minimum unit-cell volume and octahedral tilting angles in the low-temperature orthorhombic perovskite framework, defined in the Pbnm space group. The UV-vis diffuse reflectance spectrum shows a reduced band gap of 2.22(3) eV, and the photocurrent characterization in a photodetector reveals excellent properties with potential applications of this material in optoelectronic devices.

Necrotizing Sarcoid Granulomatosis: A Disease Not to be Forgotten.

Sarcoidosis is a systemic granulomatous disease of unknown aetiology characterised by the appearance of noncaseifying epithelioid granulomas in the affected organs, most commonly the lungs, skin, and eyes (Iannuzzi et al. 2007). Necrotizing Sarcoid Granulomatosis (NGS) is a rare and little-known form of disease, which also presents nodular lung lesions, and it shares pathologic and clinical findings with sarcoidosis, where the presence of necrosis may lead to misdiagnosis of tuberculosis (TB), leading to a consequent delay in treatment of the underlying entity (Chong et al. 2015). This is exactly what happened with the two cases that we present here.

Boosting Oxygen Evolution Reaction by Creating Both Metal Ion and Lattice-Oxygen Active Sites in a Complex Oxide.

Developing efficient and low-cost electrocatalysts for the oxygen evolution reaction (OER) is of paramount importance to many chemical and energy transformation technologies. The diversity and flexibility of metal oxides offer numerous degrees of freedom for enhancing catalytic activity by tailoring their physicochemical properties, but the active site of current metal oxides for OER is still limited to either metal ions or lattice oxygen. Here, a new complex oxide with unique hexagonal structure consisting of one honeycomb-like network, Ba4 Sr4 (Co0.8 Fe0.2 )4 O15 (hex-BSCF), is reported, demonstrating ultrahigh OER activity because both the tetrahedral Co ions and the octahedral oxygen ions on the surface are active, as confirmed by combined X-ray absorption spectroscopy analysis and theoretical calculations. The bulk hex-BSCF material synthesized by the facile and scalable sol-gel method achieves 10 mA cm-2 at a low overpotential of only 340 mV (and small Tafel slope of 47 mV dec-1 ) in 0.1 m KOH, surpassing most metal oxides ever reported for OER, while maintaining excellent durability. This study opens up a new avenue to dramatically enhancing catalytic activity of metal oxides for other applications through rational design of structures with multiple active sites.

Atomically Resolved Short-Range Order at the Nanoscale in the Ca-Mn-O System.

The elucidation of the reaction mechanisms involving redox processes in functional transition-metal oxides, which usually start in areas of very few nanometers in size, is yet a challenge to be satisfactorily achieved. Atomically resolved HAADF and EELS have provided both chemical and structural information at the nanoscale, which reveal the preservation of short-range cationic order in areas of 2-3 nm length as the driving force behind the reversibility of the Ca2Mn3O8-Ca2Mn3O5 redox process. Oxygen evolution is accommodated by cationic diffusion along the Ca and Mn layers of the cation-deficient Ca2Mn3O8 delafossite related structure, whereas Mn remains octahedrally coordinated.

The effect of interpersonal relationships on burnout síndrome in secondary eduation teachers / El efecto de las relaciones interpersonales en el síndrome de burnout del profesorado de Educación Secundaria Obligatoria

Background: Recent studies show that teachers, especially in Secondary Education present varying levels of burnout syndrome. This problem could be caused by internal factors unique to the subject (psychological characteristics) or external factors (overwork, social climate, etc.). Method: The objective of this study is to analyze the influence of interpersonal relationships on the development of burnout in a sample of 794 secondary education teachers from the Community of Madrid, applying structural equation modeling methodology. Results: it was observed that the teacher-student relationship has a significant effect on each of the three dimensions of the syndrome (exhaustion, cynicism, and inefficacy), and the teacher-superiors and teacher-coworker relationships show a moderate effect on these dimensions. Conclusions: The results show the importance of taking care of interpersonal relationships in schools to ensure the well-being of teachers and, ultimately, the quality of the learning process (AU)

Antecedentes: estudios recientes muestran que el profesorado, especialmente el de Educación Secundaria Obligatoria, presenta niveles variables del síndrome de burnout. Esta problemática puede estar originada en factores internos al sujeto (características psicológicas) o externos (exceso de trabajo, clima social, etc.). Método: este estudio tiene como objetivo analizar la influencia de las relaciones interpersonales en el desarrollo del burnout en una muestra de 794 profesores de ESO de la Comunidad de Madrid, mediante la aplicación de la metodología de Modelos de Ecuaciones Estructurales. Resultados: se observó que la Relación Profesor-Alumnos es la que tiene un efecto significativo en cada una de las tres dimensiones del síndrome (Agotamiento, Despersonalización y Realización), si bien las relaciones Profesor-Superiores y Profesor-Compañeros muestran un efecto moderado sobre ellas. Conclusiones: los resultados obtenidos muestran la importancia de cuidar las relaciones interpersonales en el centro para asegurar el bienestar del profesorado y, en última instancia, la calidad del proceso de aprendizaje (AU)

Enhanced figure of merit in nanostructured (Bi,Sb)2Te3 with optimized composition, prepared by a straightforward arc-melting procedure.

Sb-doped Bi2Te3 is known since the 1950s as the best thermoelectric material for near-room temperature operation. Improvements in material performance are expected from nanostructuring procedures. We present a straightforward and fast method to synthesize already nanostructured pellets that show an enhanced ZT due to a remarkably low thermal conductivity and unusually high Seebeck coefficient for a nominal composition optimized for arc-melting: Bi0.35Sb1.65Te3. We provide a detailed structural analysis of the Bi2-xSbxTe3 series (0 ≤ x ≤ 2) based on neutron powder diffraction as a function of composition and temperature that reveals the important role played by atomic vibrations. Arc-melting produces layered platelets with less than 50 nm-thick sheets. The low thermal conductivity is attributed to the phonon scattering at the grain boundaries of the nanosheets. This is a fast and cost-effective production method of highly efficient thermoelectric materials.

Non-collinear magnetic structure of manganese quadruple perovskite CdMn7O12.

We report on the magnetic structure of CdMn7O12 determined by powder neutron diffraction. We were able to measure the magnetic structure of this Cd containing and highly neutron absorbing material by optimizing the sample geometry and by blending the CdMn7O12 with Aluminum powder. Below its Néel temperature TN1 all magnetic reflections can be indexed by a single commensurate propagation vector k = (0, 0, 1). This is different to the case of CaMn7O12 where the propagation vector is incommensurate and where an in-plane helical magnetic structure has been found. We observe a commensurate non-collinear magnetic structure in CdMn7O12 with in-plane aligned magnetic moments resembling the ones in CaMn7O12. However, the commensurate propagation vector prevents the appearance of a helical magnetic structure in CdMn7O12. Finally, we also observe a third structural phase transition below ~60 K that can be attributed to phase separation.

Giant Seebeck effect in Ge-doped SnSe.

Thermoelectric materials may contribute in the near future as new alternative sources of sustainable energy. Unprecedented thermoelectric properties in p-type SnSe single crystals have been recently reported, accompanied by extremely low thermal conductivity in polycrystalline samples. In order to enhance thermoelectric efficiency through proper tuning of this material we report a full structural characterization and evaluation of the thermoelectric properties of novel Ge-doped SnSe prepared by a straightforward arc-melting method, which yields nanostructured polycrystalline samples. Ge does not dope the system in the sense of donating carriers, yet the electrical properties show a semiconductor behavior with resistivity values higher than that of the parent compound, as a consequence of nanostructuration, whereas the Seebeck coefficient is higher and thermal conductivity lower, favorable to a better ZT figure of merit.

Distant Cutaneous Metastases of Prostate Cancer: A Report of 2 Cases. / Metástasis cutáneas a distancia de cáncer de próstata: 2 casos.

Cutaneous metastases of prostate cancer are extremely rare. We present 2 cases of distant cutaneous metastases at atypical locations of prostate adenocarcinoma, and highlight the value of 2 immunohistochemical stains-prostatic acid phosphatase and prostate-specific membrane antigen-that can aid diagnosis, particularly in cases with negative staining for prostate-specific antigen.

Coinfection of Avibacterium paragallinarum and Ornithobacterium rhinotracheale in Chickens from Peru.

The coinfection of Avibacterium paragallinarum and Ornithobacterium rhinotracheale in two outbreaks of infectious coryza from Peru is reported. The diagnosis was confirmed by bacteriologic isolation, PCR testing, and sequencing of the 16S rRNA gene. The susceptibility of the isolates to 12 antimicrobial agents was tested by a disk diffusion method. The isolates were susceptible to amoxicillin/clavulanic acid and florfenicol and were resistant to oxacillin and sulfamethoxazole/trimethoprim. The coinfection of Av. paragallinarum and O. rhinotracheale and the severity of clinical signs were evaluated by experimental infection of specific-pathogen-free chickens. The group inoculated with O. rhinotracheale alone presented minimal clinical signs in 3 of 10 chickens. However, the groups inoculated with both Av. paragallinarum and O. rhinotracheale induced the most-severe clinical signs compared with the group inoculated with Av. paragallinarum alone. In conclusion, coinfections with Av. paragallinarum and O. rhinotracheale may occur, and these outbreaks could be more severe than single infections. Hence, the prevention, control, and diagnosis of Av. paragallinarum with O. rhinotracheale are important in outbreaks of infectious coryza.

Resultados iniciales de la esofaguectomía robótica en el cáncer de esófago / Initial results of robotic esophagectomy for esophageal cancer

INTRODUCCIÓN: La experiencia con la esofaguectomía robótica en el cáncer de esófago y de la unión esofagogástrica es limitada. El objetivo de este estudio es presentar nuestra experiencia actual. PACIENTES Y MÉTODOS: Estudio prospectivo, de vigilancia observacional, de las primeras 32 esofaguectomías mínimamente invasivas por cáncer con toracoscopia robótica entre septiembre de 2011 y junio de 2014. La plastia gástrica se realizó por vía laparoscópica. La toracoscopia robótica se llevó a cabo con el paciente en decúbito prono y la anastomosis intratorácica, siempre de forma manual. Se evaluaron las siguientes variables: características clínicas y patológicas, técnica quirúrgica, resultados a corto plazo (morbimortalidad) y resultados oncológicos (radicalidad y ganglios extirpados). RESULTADOS: A 32 pacientes con una edad media de 58 años (rango 34-74) se les realizó una esofaguectomía mínimamente invasiva en su totalidad: laparoscopia y toracoscopia robótica (11 McKeown y 21 Ivor Lewis). En 29 casos se administró quimiorradioterapia neoadyuvante. No hubo conversiones a cirugía abierta. El tiempo medio de consola fue 218 min (rango 190-285) y la pérdida de sangre fue de 170 ml (rango 40-255). Un paciente falleció por causa cardiológica y 9 presentaron complicaciones mayores (grado II o más de Dindo-Clavien). No hubo complicaciones respiratorias ni parálisis recurrencial. Hubo 5 fístulas intratorácicas, 4 radiológicas y una clínica, 3 quilotórax, 2 fístulas cervicales y una necrosis de la plastia. La mediana de la estancia hospitalaria fue 12 días (rango 8-50). Todas las resecciones fueron R0 y se extirparon una mediana de 16 (rango 2-23) ganglios linfáticos. CONCLUSIONES: Nuestros resultados indican inicialmente que la esofaguectomía mínimamente invasiva con toracoscopia robótica es segura y respeta los principios oncológicos

INTRODUCTION: There is scant experience with robot-assisted esophagectomy in cases of esophageal and gastro-esophageal junction cancer. Our aim is to report our current experience. PATIENTS AND METHODS: Observational cohort study of the first 32 patients who underwent minimally invasive esophagectomy for esophageal cancer from September 2011 to June 2014. The gastric tube was created laparoscopically. In the thoracic field, a robot-assisted thoracoscopic approach was performed in the prone position with intrathoracic robotic hand-sewn anastomosis. Patient and tumour characteristics, surgical technique, short-term outcomes (morbidity and mortality) and oncological results (radicality and number of removed nodes) were evaluated. RESULTS: Thirty-two patients, with a mean age of 58 years (34-74) were treated by a totally minimally invasive esophagectomy: robotic laparoscopy and thoracoscopy (11 McKeown and 21 Ivor-Lewis). Twenty-nine received neoadjuvant chemoradiotherapy. There were no conversions to open surgery. Console time was 218 minutes (190-285). Blood loss was 170 ml (40-255). One patient died from cardiac disease. Nine patients had a major complication (Dindo-Clavien grade II or higher). There was no case of respiratory complication or recurrent laryngeal nerve palsy. Five patients had intrathoracic fistula, 4 radiological and one clinical. Three had chylothorax, 2 cervical fistula and one gastric tube necrosis. The median hospital stay was 12 days (8-50). All the resections were R0 and the median of removed lymph nodes was 16 (2-23). CONCLUSIONS: Our results suggest that minimally invasive esophagectomy with robot-assisted thoracoscopy is safe and achieves oncological standards

Insight into the structure and functional application of the Sr0.95Ce0.05CoO3-δ cathode for solid oxide fuel cells.

A new perovskite cathode, Sr0.95Ce0.05CoO3-δ, performs well for oxygen-reduction reactions in solid oxide fuel cells (SOFCs). We gain insight into the crystal structure of Sr1-xCexCoO3-δ (x = 0.05, 0.1) and temperature-dependent structural evolution of Sr0.95Ce0.05CoO3-δ by X-ray diffraction, neutron powder diffraction, and scanning transmission electron microscopy experiments. Sr0.9Ce0.1CoO3-δ shows a perfectly cubic structure (a = a0), with a large oxygen deficiency in a single oxygen site; however, Sr0.95Ce0.05CoO3-δ exhibits a tetragonal perovskite superstructure with a double c axis, defined in the P4/mmm space group, that contains two crystallographically different cobalt positions, with distinct oxygen environments. The structural evolution of Sr0.95Ce0.05CoO3-δ at high temperatures was further studied by in situ temperature-dependent NPD experiments. At 1100 K, the oxygen atoms in Sr0.95Ce0.05CoO3-δ show large and highly anisotropic displacement factors, suggesting a significant ionic mobility. The test cell with a La0.8Sr0.2Ga0.83Mg0.17O3-δ-electrolyte-supported (∼300 µm thickness) configuration yields peak power densities of 0.25 and 0.48 W cm(-2) at temperatures of 1023 and 1073 K, respectively, with pure H2 as the fuel and ambient air as the oxidant. The electrochemical impedance spectra evolution with time of the symmetric cathode fuel cell measured at 1073 K shows that the Sr0.95Ce0.05CoO3-δ cathode possesses superior ORR catalytic activity and long-term stability. Mixed ionic-electronic conduction properties of Sr0.95Ce0.05CoO3-δ account for its good performance as an oxygen-reduction catalyst.