Water splitting is an environmentally friendly strategy to produce hydrogen but is limited by the oxygen evolution reaction (OER). Therefore, there is an urgent need to develop highly efficient ...electrocatalysts. Here, NiFe layered double hydroxides (NiFe LDH) with tunable Ni/Fe composition exhibit corresponding dependent morphology, layered structure, and chemical states, leading to higher activity and better stability than that of conventional NiFe LDH‐based catalysts. The characterization data show that the low overpotentials (249 mV at 10 mA cm–2), ultrasmall Tafel slopes (24 mV dec–1), and high current densities of Ni3Fe LDH result from the larger fraction of trivalent Fe3+ and the optimized local chemical environment with more oxygen coordination and ordered atomic structure for the metal site. Owing to the active intermediate species, Ni(Fe)OOH, under OER conditions and a reversible dynamic phase transition during the cycling process, the Ni3Fe LDH achieves a high current density of over 2 A cm–2 at 2.0 V, and durability of 400 h at 1 A cm–2 in a single cell test. This work provides insights into the relationship between the composition, electronic structure of the layer, and electrocatalytic performance, and offers a scalable and efficient strategy for developing promising catalysts to support the development of the future hydrogen economy.
A composition and structure‐modulated Ni3Fe layered double hydroxide (LDH) exhibits an optimal local chemical environment to trigger the oxygen evolution reaction. Compared with commercial Ir electrodes, the water electrolyzer fabricated by Ni3Fe LDH as anode shows superior current density, as well as a robust lifespan at 1 A cm–2 for 400 h.
Refractory benign esophageal strictures (RBESs) have been treated with the temporary placement of different self-expanding stents with conflicting results. We compared the clinical effectiveness of 3 ...types of stents: self-expanding plastic stents (SEPSs), biodegradable stents, and fully covered self-expanding metal stents (FCSEMSs), for the treatment of RBES.
This study prospectively evaluated 3 groups of 30 consecutive patients with RBESs who underwent temporary placement of either SEPSs (12 weeks, n = 10), biodegradable stents (n = 10) or FCSEMSs (12 weeks, n = 10). Data were collected to analyze the technical success and clinical outcome of the stents as evaluated by recurrent dysphagia, complications and reinterventions.
Stent implantation was technically successful in all patients. Migration occurred in 11 patients: 6 (60%) in the SEPS group, 2 (20%) in the biodegradable group and 3 (30%) in the FCSEMS group (P = 0.16). A total of 8/30 patients (26.6%) were dysphagia-free after the end of follow-up: 1 (10%) in the SEPS group, 3 (30%) in the biodegradable group and 4 (40%) in the FCSEMS group (P = 0.27). More reinterventions were required in the SEPS group (n = 24) than in the biodegradable group (n = 13) or the FCSEMS group (n = 13) (P = 0.24). Multivariate analysis showed that stricture length was significantly associated with higher recurrence rates after temporary stent placement (HR = 1.37; 95% CI = 1.08-1.75; P = 0.011).
Temporary placement of a biodegradable stent or of a FCSEMS in patients with RBES may lead to long-term relief of dysphagia in 30 and 40% of patients, respectively. The use of SEPSs seems least preferable, as they are associated with frequent stent migration, more reinterventions and few cases of long-term improvement. Additionally, longer strictures were associated with a higher risk of recurrence.
Abstract
Background
Dialysis patients are typically inactive and their physical activity (PA) decreases over time. Uremic toxicity has been suggested as a potential causal factor of low PA in ...dialysis patients. Post-dilution high-volume online hemodiafiltration (HDF) provides greater higher molecular weight removal and studies suggest better clinical/patient-reported outcomes compared with hemodialysis (HD).
Methods
HDFIT was a randomized controlled trial at 13 clinics in Brazil that aimed to investigate the effects of HDF on measured PA (step counts) as a primary outcome. Stable HD patients (vintage 3–24 months) were randomized to receive HDF or high-flux HD. Treatment effect of HDF on the primary outcome from baseline to 3 and 6 months was estimated using a linear mixed-effects model.
Results
We randomized 195 patients (HDF 97; HD 98) between August 2016 and October 2017. Despite the achievement of a high convective volume in the majority of sessions and a positive impact on solute removal, the treatment effect HDF on the primary outcome was +538 95% confidence interval (CI) −330 to 1407 steps/24 h after dialysis compared with HD, and was not statistically significant. Despite a lack of statistical significance, the observed size of the treatment effect was modest and driven by steps taken between 1.5 and 24.0 h after dialysis, in particular between 20 and 24 h (+197 steps; 95% CI −95 to 488).
Conclusions
HDF did not have a statistically significant treatment effect on PA 24 h following dialysis, albeit effect sizes may be clinically meaningful and deserve further investigation.
Graphical Abstract
PurposeThe changes brought by Industry 4.0 go beyond transformations in the industrial environment. The increasingly frequent digitization and robotization of activities is not only restricted to the ...industrial environment, but also to people's daily routine. People spend a large part of their time inside buildings, and maintaining adequate Indoor Environmental Quality (IEQ) is an essential factor for a healthy and productive environment. In this sense, the purpose of this study is to verify how the Internet of Things (IoT) is being used to improve the indoor environment, through sensors that instantly measure the conditions of the environment.Design/methodology/approachThe aim of this paper is to verify, through a literature review, how IoT is being used for building control (for energy saving purposes) and to monitor IEQ conditions inside buildings, in order to provide a better environment for occupants, in terms of health and comfort. By combining keywords in databases, PRISMA method was used to select the articles for analysis, and 91 articles were analyzed.FindingsThe main findings in this research are: (1) the main purpose for applying IoT inside buildings is to reduce energy consumption; (2) there is an interest in developing low-cost sensoring devices with a learning approach; (3) Machine Learning methods are mainly used for energy saving purposes and to learn about occupants' behavior inside buildings, focusing on thermal comfort; (4) sensors in the IoT era are a requirement to help improve people's comfort and well-being.Originality/valueStudies directly correlating IoT and IEQ are limited. This paper emphasises the link between them, through the presentation of recent methods to control the built environment.
Combining spectroscopic techniques with electrochemistry is a promising strategy, as it allows the detailed investigation of the species that are consumed and produced by the reaction in real time. ...However, as with any in situ coupling technique, the junction between NMR and electrochemistry presents some challenges, notably the distortion of NMR signals due to the placement of electrodes close to or within the detection region. In this work, miniaturized electrodes made of carbon fiber paper were developed and later modified with platinum. Platinum decoration by cathodic deposition was chosen, as platinum is a prominent element in electrocatalysis, able to catalyze a large variety of reactions. To evaluate the efficiency of this electrochemical system, the oxidation of ascorbic acid was used as a model reaction. It was observed that the electrodes caused substantial signal distortion when placed within the detection region (full width at half-maximum equal to 1.46 Hz), whereas no distortion was observed when the electrodes were placed 1 mm above the detection region (full width at half-maximum equal to 0.95 Hz). With this system, it was also possible to monitor the magnetoelectrolysis effect, caused by the interaction of the magnetic field with the flowing ions, leading to a doubling of the ascorbic acid oxidation rate, compared to the reaction performed without a magnetic field. In addition to its low cost and simplicity in preparation, the developed electrode system allows the electrode surface to be easily modified with other suitable catalysts.
The strong effect of magnetic field on the electrochemical (EC) reduction of a diamagnetic species was monitored in situ in a 600 MHz (14 T) NMR spectrometer. Throughout EC-NMR experiments, the ...diamagnetic species is influenced by the Lorentz force (cross product of current density and magnetic field), which in turn acts on analyte transport and, as a result, enhances reaction rates. This phenomenon, known as magnetoelectrolysis, has not been considered in several in situ EC-NMR studies in solution, electron paramagnetic resonance (EC-EPR) spectroscopy, and magnetic resonance imaging (EC-MRI) involving the oxidation and reduction of organic compounds and lithium ion batteries. Recently, we have demonstrated the presence of this effect in the electroplating of a paramagnetic ion species by monitoring it in situ in a low-field (0.23 T) NMR spectrometer. In this report, a ca. five-fold enhancement in the electroreduction rate of benzoquinone was observed when the analyses were performed in situ in the NMR spectrometer. Therefore, this work has the objective of informing the scientific community that before every electrochemical reaction carried out in situ in NMR, EPR and MRI apparatuses, the influence of the magnetic field on the reactions must be evaluated, since it can alter the mechanism and kinetics of the reaction which, if not taken into account may lead to wrong interpretations of the data.
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•The effect of the high magnetic field of NMR spectrometers on electrochemical reactions is evaluated.•High resolution NMR is not a passive technique when coupled with in situ electrochemical experiments.•The reaction kinetics change when subjected to a magnetic field.•Previous papers have not taken this effect into consideration in their studies.
La relación entre México y Turquía ha sido escasamente analizada en cuanto a los estudios de política exterior e historia mexicana, de la cual se han rescatado únicamente algunos episodios muy ...puntuales. La distancia entre México y Turquía, acentuada por el Océano Atlántico y las diferencias en cuanto a sucesos históricos y sociales, hace pensar que los acercamientos son recientes o, por lo menos, que se despliegan a partir del establecimiento formal de las relaciones diplomáticas en 1928; no obstante, existieron contactos previos tanto de corte oficial como no oficial, que datan de la época colonial e imperial respectivamente. Para lograr un análisis histórico y holístico de esta relación bilateral, se hace un mapeo de los hitos más importantes, reconstruyendo un relato que considere variables tales como el rol de las principales potencias y sus consecuentes dinámicas, así como la influencia de determinadas élites y los procesos diplomáticos que paulatinamente han asentado los contactos entre ambas partes durante el siglo XX. Siguiendo la clasificación cronológica, se considera tanto la agencia de cada estado como el peso de la estructura global en sus políticas exteriores, particularmente debido a la fuerza gravitacional de Occidente para ambos durante la Guerra Fría y una mayor liberación de sus márgenes de maniobra hacia el final de este episodio. Asimismo, se describe la proliferación de encuentros dentro de distintos foros, el interés basado en los intercambios culturales y el potencial de oportunidades que ofrece el escenario global del siglo XXI. Finalmente, se introduce una revisión crítica que cuestiona la selección de declaraciones de respaldo de un gobierno hacia otro, omitiendo posturas respecto a poblaciones marginadas de ambas latitudes. Con todo ello, este artículo expone una historia diplomática que incluye múltiples factores y que, a su vez, aboga por mayores estudios, sobre todo a partir de la reciente rapidez en el desarrollo de las relaciones y en un momento clave que culminará en 2028 con la conmemoración del centenario de esta relación.
Research on career indecision has emphasized the need to distinguish between normative indecision, which corresponds to a developmentally-appropriate state, and indecisiveness, a persistent problem ...in making decisions across multiple dimensions. This distinction is important in order to design appropriate interventions. These two types of indecision are related with two dimensions (decided–undecided and decisiveness–indecisiveness) that, if conceptualized as orthogonal, result in a diagnostic scheme with four groups (high or low in career decidedness and high or low in indecisiveness). The aim of this study was to test whether the four groups could be distinguished from each other with regard to cognitive and affective variables that have been used in career indecision research. A descriptive discriminant analysis was employed with a sample of secondary school students. The grouping variable effects of two significant functions are described and implications for career counseling and future research are discussed.
•A model based on career decidedness and indecisiveness proved to be reliable.•A descriptive discriminant analysis evidenced two significant discriminant functions.•Vocational identity and anxiety contributed most to group discrimination.•Indecisiveness could be considered a multidimensional construct.
The use of nuclear magnetic resonance (NMR) spectroscopy to study electrochemical reactions in situ (EC-NMR), in solution, was demonstrated more than four decades ago. Although, the immense potential ...of EC-NMR has been demonstrated in several applications, this method has been limited to a few specialized groups since there are no commercial EC-NMR cells or cells that can be easily assembled for routine measurements. In most of the proposed EC-NMR cells the electrodes are placed inside the NMR coil, which deteriorates the magnetic field homogeneity and reduces the signal-to-noise ratio. To minimize these interferences, electrochemical cells have been constructed as flow cells, using ultra thin metallic films as electrodes, which are too complex to be produced by non-experts, or use non-metallic electrodes that have limited electrochemical applications. In this paper we report a very simple and efficient way to construct an EC-NMR cell using standard Pt and Ag wires as electrodes. These wires are assembled as coils on capillaries and are inserted into 5 mm NMR tubes and placed approximately 0.5 mm above the NMR coil. During the in situ EC-NMR reaction the magnetohydrodynamic effect stirs the solution, homogenizing the concentration of the reagent and the product in the NMR detection region. This effect allows the concentration of the analyte to be measured in real time, even with the electrodes outside the NMR detection region. The electrode materials are not limited to Pt or Ag wires and can be replaced by other materials according to the studied reaction. Details showing how to make the electrodes are presented in a video in the supplementary material. The application and performance of this cell were demonstrated with an in situ EC-NMR study of the electro-oxidation of ascorbic acid in solution. In this particular case the magnetic field increased the reaction rate by a factor of approximately two.
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•A simple method for preparing miniaturized electrodes for the coupling between NMR and electrochemistry (video included).•Use of magnetic agitation to homogenize the solution and reduce the electrode interference.•Magnetic agitation doubled the rate of oxidation of ascorbic acid.
This study presents a facies characterization, facies succession and conceptual depositional model of the Coqueiros Formation, Lower Cretaceous of Campos Basin, based on core analyses of two wells. ...WELL-1 is a shallow water drilling located at south of Campos Basin within the Badejo structural high, and WELL-2 is an ultra deep water drilling located at north, over the “External High”. Ten carbonate facies, three siliciclastic facies, two magnesium clay mineral rich facies and two hybrid facies were identified. The carbonate facies were defined as rudstone, grainstone, packstone and mud supported carbonate rock, composed of bivalves, ostracods, and rare gastropods. Bivalve shells, mostly disarticulated with distinct degrees of fragmentation, characterized the main components of the ten carbonate facies. The siliciclastic facies are sandstones and mudstones, which occur locally. The magnesium clay rich facies is composed by stevensitic claystone and arenites. The mixture of bioclasts, siliciclastic grains, stevensite ooids and peloids constitute hybrid facies. The depositional processes involved waves and storm currents, as well as storm refluxes and tectonically-driven gravitational deposits, which mixed particles from different basinal sites producing the hybrid facies. The conceptual depositional model for each geological setting were elaborated based on facies stacking pattern analysis. A hybrid ramp in rift setting, studied in WELL-1, is characterized by carbonate, argillaceous, siliciclastic and hybrid successions, suggesting a strong terrigenous influence and variation of the lake water chemistry. An isolated bioclastic high in a rift setting, studied in WELL-2, is basically constructed by bioclastic sequences with local occurrence of siliciclastic mudstones deposited from hypopycnal plumes in relatively deep water. The extraordinary dominance of bivalve mollusks occurred during the lower Aptian stage in Campos Basin, in an active rift basin, with robust bioclastic productivity within protected basement highs. In structures near to the lake border, predominated siliciclastic and hybrid rock sequences as a result of high structural gradients and terrigenous input. Isolated highs from lakeshores were protected from external terrigenous influence. In lacustrine deep water bioclastic and hybrid arenites were deposited as fans generated by gravitational flows triggered by destabilization of shallower water deposits during episodic storms and tectonic activities. This study of the coquina deposits constructional model within a nearshore and also in a offshore lacustrine system is a useful knowledge for the understanding of coquina reservoir distribution and is applicable in the exploratory investigation of new areas with correlate lacustrine systems.
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•Petrographic facies characterization of Pre-salt, lower Cretaceous of Campos Basin.•Proposition of conceptual model for hybrid ramp and isolated bioclastic platform.•Near to the lake border, predominated siliciclastic and hybrid rock sequences.•At isolated highs there are major bioclastic development, without external terrigenous influence.
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