Morphological and Structural Characterization of (Pt, Au, and Ag) Nanoparticle/Zn-MOF-74 Composites.

Metallic nanoparticles (NPs) were decorated onto Zn-MOF-74 crystals by photoreducing different metal precursors (Pt, Au, and Ag) using ultraviolet (UV) light in an aqueous solution with different metal concentrations without using additional stabilizers. X-ray diffraction revealed the three-dimensional structural integrity and crystallinity conservation of Zn-MOF-74 crystals during the UV decoration process. Raman spectroscopy showed a minor rearrangement in the structure of the Zn-MOF-74 crystal surface after NP decoration. X-ray photoelectron spectroscopy confirmed the metal oxidation states of Zn and NPs. High-resolution transmission electron microscopy images proved the surface decoration of Zn-MOF-74 crystals with spherical metallic NPs with diameters between 2.4 and 9.8 nm.

Hexamethylenetetramine-tridecanedioic acid (1/1): temperature-induced order-disorder structural phase transitions with phase co-existence.

The cocrystal hexamethylenetetramine-tridecanedioic acid (1/1) (HMT-C13), C6H12N4·C13H24O4, was investigated by single-crystal X-ray diffraction techniques at several temperatures during cooling and heating processes. Our results show the formation of two crystalline phases, separated by a large temperature phase co-existence between 290 and 340 K. Phase I, stable above 341 K, presents an orthorhombic structure described in the space group Bmmb, with one N4(CH2)6·C13H22O4 adduct in its asymmetric unit. Phase II, stable below 290 K, presents a monoclinic symmetry described by the space group P21/c, with two N4(CH2)6·C13H22O4 adducts in its asymmetric unit. The phase co-existence is observed both upon cooling and heating, and seems to be related to a complex domain-growth dynamic within the crystal.

Capacitación estratégica e inductiva en cuidados de heridas para enfermeros domiciliarios / Strategic and inductive wound care training for homecare nurses

Objetivos: Asegurar el uso de la Guía Institucional para los cuidados de úlceras por presión y la adecuada inducción de los profesionales de reciente ingreso. Metodología: Estudio descriptivo retrospectivo aleatorio aplicado a la dotación de enfermería humano en sistemas tegumentarios y piel, implementando las innovaciones tecnológicas disponibles. Resultados: n: 43 prestaciones (cuidados de úlceras por presión). Alumnado: 52 enfermeros asistenciales como recurso humano eje de capacitación. En la cohorte auditada se evaluó la instrumentación de la Guía Institucional por parte de los profesionales de medicina domiciliaria del Hospital Italiano de Buenos Aires, Argentina, en el que se utilizó una esfera pragmática, mediante la cual se capacitó al recurso. Conclusiones: Se concluye el programa educativo, con el que se obtiene un alto porcentaje de instrumentación adecuada de la guía hospitalaria por parte de los educandos (promedio porcentual 98,8%) y se expone una efectiva inducción para los profesionales de reciente ingreso

Objectives: To ensure the use of the Institutional Guidelines for pressure ulcer care and proper induction of newly recruited professionals. Methodology: A randomized retrospective descriptive study applied to the Nursing Ambulatory Medicine Staff of the Hospital Italiano of Buenos Aires, Argentina, in which by a pragmatic sphere, human resources were trained in tegumentary systems and skin, implementing innovating available technology. Results: n: 43 benefits (care of pressure ulcers). Students: 52 clinical nurses as human resource training axis. In the audited cohort instrumentation of Institutional Guide by professionals was evaluated. Conclusions: We conclude the Educational Program, obtaining a high percentage of suitable instrumentation of hospital guide by learners (average percentage 98.8%) and an effective induction of professionals of recent entry

Structural, optical and photoelectrochemical characterizations of monoclinic Ta3N5 thin films.

Monoclinic Ta3N5 thin films were synthesized by thermal nitridation of amorphous Ta2O5 films directly sputtered by radio frequency magnetron sputtering. The samples were studied by high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis-NIR spectrophotometry, rietveld refinements, spectroscopic ellipsometry and electrochemical techniques. The surface composition of Ta3N5 thin film was found to be different than the underlying film, affecting the optical properties of the material. Rietveld refinement has confirmed that the nitridation process results in Schottky and oxygen substitutional defects within the crystalline structure of monoclinic Ta3N5 thin film. The optical constants of the film were obtained by spectroscopic ellipsometry within a spectral range of 4.60-0.54 eV, i.e. 270-2300 nm. The suitable parameterization was found to consist of three Tauc-Lorentz and one Lorentz oscillators. The conduction band, valence band and the flat band positions were determined by photoelectrochemical techniques, presenting a strong dependence on pH of the eletrolyte. Improved photocurrent was obtained in alkaline conditions and attributed to the shorter depletion region width measured by Mott-Schottky and the lower recombination life time measured by open circuit potential decay analyses.

Straightforward synthesis of bimetallic Co/Pt nanoparticles in ionic liquid: atomic rearrangement driven by reduction-sulfidation processes and Fischer-Tropsch catalysis.

Unsupported bimetallic Co/Pt nanoparticles (NPs) of 4.4 ± 1.9 nm can be easily obtained by a simple reaction of [bis(cylopentadienyl)cobalt(ii)] and [tris(dibenzylideneacetone) bisplatinum(0)] complexes in 1-n-butyl-3-methylimidazolium hexafluorophosphate IL at 150 °C under hydrogen (10 bar) for 24 h. These bimetallic NPs display core-shell like structures in which mainly Pt composes the external shell and its concentration decreases in the inner-shells (CoPt3@Pt-like structure). XPS and EXAFS analyses show the restructuration of the metal composition at the NP surface when they are subjected to hydrogen and posterior H2S sulfidation, thus inducing the migration of Co atoms to the external shells of the bimetallic NPs. Furthermore, the isolated bimetallic NPs are active catalysts for the Fischer-Tropsch synthesis, with selectivity for naphtha products.

Photocatalytic hydrogen production of Co(OH)2 nanoparticle-coated α-Fe2O3 nanorings.

The production of hydrogen from water using only a catalyst and solar energy is one of the most challenging and promising outlets for the generation of clean and renewable energy. Semiconductor photocatalysts for solar hydrogen production by water photolysis must employ stable, non-toxic, abundant and inexpensive visible-light absorbers capable of harvesting light photons with adequate potential to reduce water. Here, we show that α-Fe2O3 can meet these requirements by means of using hydrothermally prepared nanorings. These iron oxide nanoring photocatalysts proved capable of producing hydrogen efficiently without application of an external bias. In addition, Co(OH)2 nanoparticles were shown to be efficient co-catalysts on the nanoring surface by improving the efficiency of hydrogen generation. Both nanoparticle-coated and uncoated nanorings displayed superior photocatalytic activity for hydrogen evolution when compared with TiO2 nanoparticles, showing themselves to be promising materials for water-splitting using only solar light.

Controlled synthesis of Mn3O4 nanoparticles in ionic liquids.

This work describes a simple one-step synthesis of Mn3O4 nanoparticles by thermal decomposition of [Mn(acac)2] (acac = acetylacetonate) using imidazolium ionic liquids (ILs) and a conventional solvent, oleylamine, for comparison. The Mn3O4 nanoparticles were characterized by XRD, ATR-FTIR, TEM, Raman, UV/VIS and magnetometry techniques. The addition of 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide IL (BMI·NTf2) yielded a smaller particle size (9.9 ± 1.8 nm) with better dispersion and more regular sizes than synthesis using oleylamine as the solvent (12.1 ± 3.0 nm). The complete conversion of the precursor to Mn3O4 nanoparticles occurred after 96 h at 180 °C for the reaction performed in BMI·NTf2. However, under these reaction conditions in oleylamine, no precursor was detected, but two different phases were observed: a major phase corresponding to Mn3O4 and a minor phase corresponding to MnO2. Magnetometry revealed that Mn3O4 nanoparticles synthesized in either oleylamine or BMI·NTf2 exhibited ferrimagnetic behavior at low temperatures, whereas they were paramagnetic at room temperature. As expected, the blocking temperature and the coercivity decreased with the size of nanoparticles. Our results demonstrate that reaction conditions such as time, and the nature of the ionic liquid play important roles in determining the size of Mn3O4 nanoparticles.

[Prognosis of presyncope in patients with structural heart disease]. / Pronóstico del presíncope en pacientes con cardiopatía estructural.

INTRODUCTION AND OBJECTIVES: Few data are available on the prognosis of presyncope in patients with structural heart disease. The aim of this study was to compare the clinical characteristics and long-term prognosis of patients with structural heart disease admitted for presyncope or syncope in the cardiology department of a tertiary hospital. METHODS: We reviewed the medical records of 449 patients (65% men, mean age 66.8 [13.1] years) with structural heart disease admitted because of syncope (n = 272) or presyncope (n = 177) during the period from 1992 to 1998. Clinical and demographic variables were analyzed and the final diagnosis was classified according to European Society of Cardiology criteria. The follow-up (available in 97.1% of patients) consisted of a personal interview with the patient or a review of the medical records and an interview with the relatives of the patients who had died. RESULTS: Both groups had similar demographic and clinical characteristics, except for the presence of atrial fibrillation on admission, which was more common in the presyncope group. Previous syncopal episodes were more frequent in patients admitted for syncope. The mechanism of the episode was considered arrhythmic in 25.7% of the patients with syncope and 22.0% of those in the presyncope group (P=.37). After a mean follow-up of 57.4 [30.5 months the survival curves were similar for both groups and no significant differences were found regarding the causes of death or the rate of sudden death. CONCLUSIONS: The clinical characteristics and the long-term prognosis in patients with structural heart disease admitted to a cardiology department for presyncope are similar to those of patients admitted for syncope. This suggests that the approach to diagnosis and risk stratification should be similar in both groups of patients.

Analysis of ionic ratios in myocardial tissue and their relation to cardiac damage.

The authors evaluated the usefulness of the postmortem biochemical analysis of ionic ratios in different parts of the heart and their relation to cardiac damage caused by chest trauma, as observed by anatomopathologic study. Fifty-nine 59 cases were studied, selected from routine necropsies, and samples were taken from different sites of cardiac tissue. The cause of death was trauma in 40 cases and nontraumatic causes in 19 cases. The object of this study was to analyze the levels of Na+, K+, Ca+2, Mg+2, and Zn+2 in different zones of the heart, and the relationship between intracellular and extracellular ion ratios and the different causes of death and any anatomopathologic alterations observed. The biochemical tests revealed a possible relation between the ionic values and cause of death. Alterations in cell membrane permeability and corresponding modification of the ionic ratios were produced earlier than histologic alterations, which need longer to establish themselves whether or not they follow a traumatic process.