Reactive capture and electrochemical conversion of CO2 with ionic liquids and deep eutectic solvents.

Ionic liquids (ILs) and deep eutectic solvents (DESs) have tremendous potential for reactive capture and conversion (RCC) of CO2 due to their wide electrochemical stability window, low volatility, and high CO2 solubility. There is environmental and economic interest in the direct utilization of the captured CO2 using electrified and modular processes that forgo the thermal- or pressure-swing regeneration steps to concentrate CO2, eliminating the need to compress, transport, or store the gas. The conventional electrochemical conversion of CO2 with aqueous electrolytes presents limited CO2 solubility and high energy requirement to achieve industrially relevant products. Additionally, aqueous systems have competitive hydrogen evolution. In the past decade, there has been significant progress toward the design of ILs and DESs, and their composites to separate CO2 from dilute streams. In parallel, but not necessarily in synergy, there have been studies focused on a few select ILs and DESs for electrochemical reduction of CO2, often diluting them with aqueous or non-aqueous solvents. The resulting electrode-electrolyte interfaces present a complex speciation for RCC. In this review, we describe how the ILs and DESs are tuned for RCC and specifically address the CO2 chemisorption and electroreduction mechanisms. Critical bulk and interfacial properties of ILs and DESs are discussed in the context of RCC, and the potential of these electrolytes are presented through a techno-economic evaluation.

Key Experimental Considerations When Evaluating Functional Ionic Liquids for Combined Capture and Electrochemical Conversion of CO2.

Ionic liquids (ILs) are considered functional electrolytes for the electrocatalytic reduction of CO2 (ECO2R) due to their role in the double-layer structure formation and increased CO2 availability at the electrode surface, which reduces the voltage requirement. However, not all ILs are the same, considering the purity and degree of the functionality of the IL. Further, there are critical experimental factors that impact the evaluation of ILs for ECO2R including the reference electrode, working electrode construction, cosolvent selection, cell geometry, and whether the electrochemical cell is a single compartment or a divided cell. Here, we describe improved synthesis methods of imidazolium cyanopyrrolide IL for electrochemical studies in consideration of precursor composition and reaction time. We explored how IL with cosolvents (i.e. acetonitrile, dimethylformamide, dimethyl sulfoxide, propylene carbonate, and n-methyl-2-pyrrolidone) affects conductivity, CO2 mass transport, and ECO2R activation overpotential together with the effects of electrode materials (Sn, Ag, Au, and glassy carbon). Acetonitrile was found to be the best solvent for lowering the onset potential and increasing the catalytic current density for the production of CO owing to the enhanced ion mobility in combination with the silver electrode. Further, the ECO2R activity of molecular catalysts Ni(cyclam)Cl2 and iron tetraphenylsulfonato porphyrin (FeTPPS) on the carbon cloth electrode maintained high Faradaic efficiencies for CO in the presence of the IL. This study presents best practices for examining nontraditional multifunctional electrolytes amenable to integrated CO2 capture and conversion technologies for homogeneous and heterogeneous ECO2R.

Development of a Six-Degree-of-Freedom Analog 3D Tactile Probe Based on Non-Contact 2D Sensors.

In this paper, a six-degree-of-freedom analog tactile probe with a new, simple, and robust mechanical design is presented. Its design is based on the use of one elastomeric ring that supports the stylus carrier and allows its movement inside a cubic measuring range of ±3 mm. The position of the probe tip is determined by three low-cost, noncontact, 2D PSD (position-sensitive detector) sensors, facilitating a wider application of this probe to different measuring systems compared to commercial ones. However, several software corrections, regarding the size and orientation of the three LED light beams, must be carried out when using these 2D sensors for this application due to the lack of additional focusing or collimating lenses and the very wide measuring range. The development process, simulation results, correction models, experimental tests, and calibration of this probe are presented. The results demonstrate high repeatability along the X-, Y-, and Z-axes (2.0 µm, 2.0 µm, and 2.1 µm, respectively) and overall accuracies of 6.7 µm, 7.0 µm, and 8.0 µm, respectively, which could be minimized by more complex correction models.

X-ray absorption spectroscopy insights on the structure anisotropy and charge transfer in Chevrel Phase chalcogenides.

The electronic structure and local coordination of binary (Mo6T8) and ternary Chevrel Phases (MxMo6T8) are investigated for a range of metal intercalant and chalcogen compositions. We evaluate differences in the Mo L3-edge and K-edge X-ray absorption near edge structure across the suite of chalcogenides MxMo6T8 (M = Cu, Ni, x = 1-2, T = S, Se, Te), quantifying the effect of compositional and structural modification on electronic structure. Furthermore, we highlight the expansion, contraction, and anisotropy of Mo6 clusters within these Chevrel Phase frameworks through extended X-ray absorption fine structure analysis. Our results show that metal-to-cluster charge transfer upon intercalation is dominated by the chalcogen acceptors, evidenced by significant changes in their respective X-ray absorption spectra in comparison to relatively unaffected Mo cations. These results explain the effects of metal intercalation on the electronic and local structure of Chevrel Phases across various chalcogen compositions, and aid in rationalizing electron distribution within the structure.

Machine Learning Guided Synthesis of Multinary Chevrel Phase Chalcogenides.

The Chevrel phase (CP) is a class of molybdenum chalcogenides that exhibit compelling properties for next-generation battery materials, electrocatalysts, and other energy applications. Despite their promise, CPs are underexplored, with only ∼100 compounds synthesized to date due to the challenge of identifying synthesizable phases. We present an interpretable machine-learned descriptor (Hδ) that rapidly and accurately estimates decomposition enthalpy (ΔHd) to assess CP stability. To develop Hδ, we first used density functional theory to compute ΔHd for 438 CP compositions. We then generated >560 000 descriptors with the new machine learning method SIFT, which provides an easy-to-use approach for developing accurate and interpretable chemical models. From a set of >200 000 compositions, we identified 48 501 CPs that Hδ predicts are synthesizable based on the criterion that ΔHd < 65 meV/atom, which was obtained as a statistical boundary from 67 experimentally synthesized CPs. The set of candidate CPs includes 2307 CP tellurides, an underexplored CP subset with a predicted preference for channel site occupation by cation intercalants that is rare among CPs. We successfully synthesized five of five novel CP tellurides attempted from this set and confirmed their preference for channel site occupation. Our joint computational and experimental approach for developing and validating screening tools that enable the rapid identification of synthesizable materials within a sparse class is likely transferable to other materials families to accelerate their discovery.

Fe(II) Induced Reduction of Incorporated U(VI) to U(V) in Goethite.

Over 60 years of nuclear activities have resulted in a global legacy of radioactive wastes, with uranium considered a key radionuclide in both disposal and contaminated land scenarios. With the understanding that U has been incorporated into a range of iron (oxyhydr)oxides, these minerals may be considered a secondary barrier to the migration of radionuclides in the environment. However, the long-term stability of U-incorporated iron (oxyhydr)oxides is largely unknown, with the end-fate of incorporated species potentially impacted by biogeochemical processes. In particular, studies show that significant electron transfer may occur between stable iron (oxyhydr)oxides such as goethite and adsorbed Fe(II). These interactions can also induce varying degrees of iron (oxyhydr)oxide recrystallization (<4% to >90%). Here, the fate of U(VI)-incorporated goethite during exposure to Fe(II) was investigated using geochemical analysis and X-ray absorption spectroscopy (XAS). Analysis of XAS spectra revealed that incorporated U(VI) was reduced to U(V) as the reaction with Fe(II) progressed, with minimal recrystallization (approximately 2%) of the goethite phase. These results therefore indicate that U may remain incorporated within goethite as U(V) even under iron-reducing conditions. This develops the concept of iron (oxyhydr)oxides acting as a secondary barrier to radionuclide migration in the environment.

Study on LT Accuracy Improvement by Calibration Based on Network Measurements.

Laser trackers (LT) are widely used to calibrate other machines. Nevertheless, very little is known about calibrating an LT. There are some standards that allow us to evaluate the LT performance. However, they require specialized equipment. A calibration procedure to improve the LT accuracy in an easy and fast way is presented in this paper. This method is based on network measurements where a set of reflectors were measured from different LT positions in a working environment. The methodology proposed deal with the lack of nominal data of the reflector mesh. A measurement scenario was defined, based on error parameter dependence on distances and angles, thus, obtaining those positions more sensitive to errors. The influence of the incidence angle of the laser beam on the reflector was characterized, revealing that its contribution to the LT measurement error can be up to 13 µm. Error kinematic parameters were identified to provide the optimum value of an objective function, where the reflector mesh nominal data were unknown. The calibration procedure was validated with nominal data, by measuring a set of reflectors located on a coordinate measuring machine. The findings of this study suggested that the LT accuracy can be improved up to 25%. Moreover, the method can be carried out by the LT user without requiring specialized equipment.

Study on Machine Tool Positioning Uncertainty Due to Volumetric Verification.

Volumetric verification is based on the machine tool (MT) kinematic model, along with its geometric errors. Although users often ignore the uncertainty of verification, the use of the MT as a traceable measurement system in the manufacturing process has increased the need for professionals to be aware of it. This paper presents an improvement in the MT kinematic model, introducing in it the influence of verification uncertainty sources. These sources have been classified into four groups: the MT, the measurement system itself, the measurement strategy, and the optimization strategy. As the developed model exhibits non-linear behavior, the Monte Carlo method was used to determine the influence of the measurement system on verification uncertainty using synthetic tests. In this manner, an improved estimation of the MT uncertainty can be obtained. Therefore, if the MT is used as a traceable measurement system, its accuracy should not be higher than the laser tracker (LT) verification influence. It hence shows the importance of LT influence.

Microwave near-field imaging of two-dimensional semiconductors.

Optimizing new generations of two-dimensional devices based on van der Waals materials will require techniques capable of measuring variations in electronic properties in situ and with nanometer spatial resolution. We perform scanning microwave microscopy (SMM) imaging of single layers of MoS2 and n- and p-doped WSe2. By controlling the sample charge carrier concentration through the applied tip bias, we are able to reversibly control and optimize the SMM contrast to image variations in electronic structure and the localized effects of surface contaminants. By further performing tip bias-dependent point spectroscopy together with finite element simulations, we distinguish the effects of the quantum capacitance and determine the local dominant charge carrier species and dopant concentration. These results underscore the capability of SMM for the study of 2D materials to image, identify, and study electronic defects.

Improving O2 production of WO3 photoanodes with IrO2 in acidic aqueous electrolyte.

WO3 is a promising candidate for a photoanode material in an acidic electrolyte, in which it is more stable than most metal oxides, but kinetic limitations combined with the large driving force available in the WO3 valence band for water oxidation make competing reactions such as the oxidation of the acid counterion a more favorable reaction. The incorporation of an oxygen evolving catalyst (OEC) on the WO3 surface can improve the kinetics for water oxidation and increase the branching ratio for O2 production. Ir-based OECs were attached to WO3 photoanodes by a variety of methods including sintering from metal salts, sputtering, drop-casting of particles, and electrodeposition to analyze how attachment strategies can affect photoelectrochemical oxygen production at WO3 photoanodes in 1 M H2SO4. High surface coverage of catalyst on the semiconductor was necessary to ensure that most minority-carrier holes contributed to water oxidation through an active catalyst site rather than a side-reaction through the WO3/electrolyte interface. Sputtering of IrO2 layers on WO3 did not detrimentally affect the energy-conversion behavior of the photoanode and improved the O2 yield at 1.2 V vs. RHE from ~0% for bare WO3 to 50-70% for a thin, optically transparent catalyst layer to nearly 100% for thick, opaque catalyst layers. Measurements with a fast one-electron redox couple indicated ohmic behavior at the IrO2/WO3 junction, which provided a shunt pathway for electrocatalytic IrO2 behavior with the WO3 photoanode under reverse bias. Although other OECs were tested, only IrO2 displayed extended stability under the anodic operating conditions in acid as determined by XPS.

Articulated arm coordinate measuring machine calibration by laser tracker multilateration.

A new procedure for the calibration of an articulated arm coordinate measuring machine (AACMM) is presented in this paper. First, a self-calibration algorithm of four laser trackers (LTs) is developed. The spatial localization of a retroreflector target, placed in different positions within the workspace, is determined by means of a geometric multilateration system constructed from the four LTs. Next, a nonlinear optimization algorithm for the identification procedure of the AACMM is explained. An objective function based on Euclidean distances and standard deviations is developed. This function is obtained from the captured nominal data (given by the LTs used as a gauge instrument) and the data obtained by the AACMM and compares the measured and calculated coordinates of the target to obtain the identified model parameters that minimize this difference. Finally, results show that the procedure presented, using the measurements of the LTs as a gauge instrument, is very effective by improving the AACMM precision.

From Ln2O2S to Ln10OS14: exploring the sulphur spectrum of trivalent lanthanoid oxysulphides.

While Ln2O2S oxysulphides have increasingly gained attention due to their structural and optoelectronic properties, an expansive compositional space lies beyond as the sulphur-to-oxygen ratio increases. In these oxysulphides, the compounded effect of the 4f states is manifold in the lanthanoid ions and the changing bonding and environment symmetry enables the tuning of their electronic structure and photophysical properties. Their challenging syntheses have made these materials largely unexplored, but recent efforts have been made to bridge the knowledge gap. In this article we present some of the structural characteristics and photophysical properties of the lanthanoid oxysulphide spectrum LnxOySz.

Multi-dimensional designer catalysts for negative emissions science (NES): bridging the gap between synthesis, simulations, and analysis.

Negative emissions technologies will play a critical role in limiting global warming to sustainable levels. Electrocatalytic and/or photocatalytic CO2 reduction will likely play an important role in this field moving forward, but efficient, selective catalyst materials are needed to enable the widespread adoption of these processes. The rational design of such materials is highly challenging, however, due to the complexity of the reactions involved as well as the large number of structural variables which can influence behavior at heterogeneous interfaces. Currently, there is a significant disconnect between the complexity of materials systems that can be handled experimentally and those that can be modeled theoretically with appropriate rigor and bridging these gaps would greatly accelerate advancements in the field of Negative Emissions Science (NES). Here, we present a perspective on how these gaps between materials design/synthesis, characterization, and theory can be resolved, enabling the rational development of improved materials for CO2 conversion and other NES applications.

Adsorption of perfluorooctanoic acid from water by pH-modulated Brönsted acid and base sites in mesoporous hafnium oxide ceramics.

Per- and polyfluoroalkyl substances (PFAS) are increasingly appearing in drinking water sources globally. Our work focuses specifically on the adsorption of the legacy perfluorooctanoic acid (PFOA) using mesoporous hafnium oxide (MHO) ceramic synthesized via a sol-gel process. Experiments were performed at varying pH to determine the effect of surface charge on adsorption capacity of PFOA by MHO, and to postulate adsorption behavior. At pH 2.3, the adsorption capacity of PFOA on MHO was 20.9 mg/g, whereas at a higher pH of 6.3, it was much lower at 9.2 mg/g. This was due to increased coulombic attractions at lower pH between the positively charged conjugate acid active sites on MHO surface and negatively charged deprotonated PFOA anion in solution. After adsorption, the solid MHO was regenerated via calcination, reducing the amount of toxic solid waste to be disposed since the adsorbent is regenerated, and the PFOA is completely removed.

Role of newer antidiabetic drugs on cardiovascular prevention and heart failure. / Rol de nuevos fármacos antidiabéticos en prevención cardiovascular e insuficiencia cardiaca.

Beyond glucemic control there are other important goals when it comes to providing integral care to patients with diabetes mellitus. A bibliographic review was made in order to identify the role played by new antidiabetic drugs in cardiovascular prevention and heart failure. The use of SLGT2i and GLP1a leads to a significant decrease in cardiovascular events, with no difference between the two, except when it comes to hospitalizations for heart failure, where the superiority of the last ones (especially dapaglifozin and empaglifozin) is evident. The current evidence regarding the effect of dpp-4i is diverse, although an increased risk of hospitalizations for heart failure is observed with the use of some drugs of this class (saxagliptin).

Configuration Optimisation of Laser Tracker Location on Verification Process.

Machine tools are verified and compensated periodically to improve accuracy. The main aim of machine tool verification is to reduce the influence of quasi-static errors, especially geometric errors. As these errors show systematic behavior, their influence can be compensated. However, verification itself is influenced by random uncertainty sources that are usually not considered but affect the results. Within these uncertainty sources, laser tracker measurement noise is a random error that should not be ignored and can be reduced through adequate location of the equipment. This paper presents an algorithm able to analyse the influence of laser tracker location based on nonlinear optimisation, taking into consideration its specifications and machine tool characteristics. The developed algorithm uses the Monte Carlo method to provide a zone around the machine tool where the measurement system should be located in order to improve verification results. To achieve this aim, different parameters were defined, such as the number of tests carried out, and the number and distribution of points, and their influence on the error due to the laser tracker location analysed.

Stabilizing Hydrogen Adsorption through Theory-Guided Chalcogen Substitution in Chevrel-Phase Mo6X8 (X=S, Se, Te) Electrocatalysts.

In this work, we implement a facile microwave-assisted synthesis method to yield three binary Chevrel-Phase chalcogenides (Mo6X8; X = S, Se, Te) and investigate the effect of increasing chalcogen electronegativity on hydrogen evolution catalytic activity. Density functional theory predictions indicate that increasing chalcogen electronegativity in these materials will yield a favorable electronic structure for proton reduction. This is confirmed experimentally via X-ray absorption spectroscopy as well as traditional electrochemical analysis. We have identified that increasing the electronegativity of X in Mo6X8 increases the hydrogen adsorption strength owing to a favorable shift in the p-band position as well as an increase in the Lewis basicity of the chalcogen, thereby improving hydrogen evolution reaction energetics. We find that Mo6S8 exhibits the highest hydrogen evolution activity of the Mo6X8 series of catalysts, requiring an overpotential of 321 mV to achieve a current density of 10 mA cm-2ECSA, a Tafel slope of 74 mV per decade, and an exchange current density of 6.01 × 10-4 mA cm-2ECSA. Agreement between theory and experiment in this work indicates that the compositionally tunable Chevrel-Phase chalcogenide family is a promising framework for which electronic structure can be predictably modified to improve catalytic small-molecule reduction reactivity.

Gender differences in acute coronary syndrome. "Comandante Manuel Fajardo" Hospital, 2016-2017. / Diferencias sexuales en el síndrome coronario agudo. Hospital Comandante Manuel Fajardo, 2016-2017.

INTRODUCTION: There are both biological and sociocultural differences in patients with cardiovascular diseases. Inequalities in the prognosis between women and men are due to several variables, including specific risk factors for females, discrepancies in treatment strategies, and pathophysiological differences. OBJECTIVE: To identify gender differences in patients with acute coronary syndrome. METHODS: An observational, analytical, cross-sectional study was carried out on the gender differences in 170 patients with a diagnosis of acute coronary syndrome who were discharged from the Intensive Coronary Care Unit of the Comandante Manuel Fajardo Clinical-Surgical Hospital in 2016 and 2017. RESULTS: Females had a statistically very significant association, with a higher mean age (68 vs. 62, P<.01) and with a history of arterial hypertension (91.2 vs. 72.3% P<.01). The smoking habit showed a statistically significant association with male individuals (50.5 vs. 30.4% P=.017). Males had a significantly higher median creatinine (90µmol/L vs. 80µmol/L, P<.01). Women showed an increased risk of haemodynamic complications (OR=3.11, 95% CI=1.20-8.04). CONCLUSIONS: In women with acute coronary syndrome, being female is associated with older age, a history of arterial hypertension, and the appearance of haemodynamic complications during admission. Males are associated with smoking habits and higher concentrations of serum creatinine.

Factores asociados al síndrome de Wellens en pacientes con síndrome coronario agudo sin elevación del segmento ST / Factors associated to Wellens' syndrome in patients with acute coronary syndrome without ST-segment elevation

Introducción: El síndrome de Wellens constituye un equivalente del síndrome coronario agudo con elevación del segmento ST. Este incluye dos patrones electrocardiográficos que sugieren lesión crítica de la arteria descendente anterior. Objetivo: Evaluar probables factores asociados al síndrome de Wellens en pacientes con síndrome coronario agudo sin elevación del segmento ST y lesiones coronarias significativas en la arteria descendente anterior. Material y métodos: Se realizó un estudio observacional, analítico, transversal en pacientes con diagnóstico de síndrome coronario agudo sin elevación del ST y lesión significativa en la arteria descendente anterior, comprobada mediante coronariografía, ingresados en la unidad de cuidados coronarios intensivos del Hospital Clínico-Quirúrgico Manuel Fajardo entre el 2016 y 2019. Resultados: La edad media fue de 66 años, predominó el sexo masculino (53,9 por ciento) y el antecedente de hipertensión arterial (89,5 por ciento). Los pacientes con síndrome de Wellens tuvieron un significativo menor porcentaje de antecedente de cardiopatía isquémica (58,1 por ciento vs. 84,8 por ciento; p = 0,012). Además, el síndrome arrojó asociación estadísticamente muy significativa con la condición de fumador activo (51,2 por ciento vs. 15,2 por ciento; p < 0,01). No se encontró relación estadística significativa entre el síndrome de Wellens y el resultado angiográfico. Conclusiones: La presencia de los patrones electrocardiográficos del síndrome de Wellens se asocia con el hábito tabáquico en pacientes con síndrome coronario agudo sin elevación del segmento ST y lesiones coronarias en la arteria descendente anterior, y su ausencia se asocia con el antecedente de cardiopatía isquémica en el mismo subgrupo de individuos(AU)

Introduction: Wellens' syndrome is equivalent to acute coronary syndrome with ST-segment elevation. It includes two electrocardiographic patterns suggesting a critical lesion in the anterior descending artery. Objective: Evaluate probable factors associated to Wellens' syndrome in patients with acute coronary syndrome without ST-segment elevation and significant coronary lesions in the anterior descending artery. Methods: A cross-sectional observational analytical study was conducted of patients diagnosed with acute coronary syndrome without ST-segment elevation and significant lesion in the anterior descending artery verified by coronary arteriography, admitted to the intensive coronary care unit at Manuel Fajardo Clinical Surgical Hospital in the period 2016-2019. Results: Mean age was 66 years, with a predominance of the male sex (53.9 percent) and a history of hypertension (89.5 percent). Patients with Wellens' syndrome had a significantly lower percentage of ischemic heart disease antecedents (58.1 percent vs. 84.8 percent; p = 0.012). A very significant statistical association was observed between the syndrome and active smoking (51.2 percent vs. 15.2 percent; p < 0.01). A significant statistical relationship was not found between Wellens' syndrome and angiographic results. Conclusions: The presence of electrocardiographic patterns of Wellens' syndrome is associated to smoking in patients with acute coronary syndrome without ST-segment elevation and coronary lesions in the anterior descending artery, whereas their absence is associated to a history of ischemic heart disease in the same subgroup of individuals(AU)

Rol de nuevos fármacos antidiabéticos en prevención cardiovascular e insuficiencia cardiaca / Role of newer antidiabetic drugs on cardiovascular prevention and heart failure

Más allá del control de la glucemia existen otros objetivos importantes a la hora de brindar atención integral a pacientes con diabetes mellitus. Se realizó una revisión bibliográfica con el objetivo de identificar el papel que desempeñan los nuevos fármacos antidiabéticos en la prevención cardiovascular y la insuficiencia cardiaca. El uso de SGLT2i y GLP-1a acarrea una disminución significativa de eventos cardiovasculares, sin diferencias entre ambos, exceptuando las hospitalizaciones por insuficiencia cardiaca, en donde es evidente la superioridad de estos últimos (en especial dapaglifozina y empaglifozina). La evidencia actual respecto al efecto de los DPP-4i es diversa, aunque se observa un aumento del riesgo de hospitalizaciones por insuficiencia cardiaca con el consumo de algunos fármacos de esta clase (saxagliptina).(AU)

Beyond glucemic control there are other important goals when it comes to providing integral care to patients with diabetes mellitus. A bibliographic review was made in order to identify the role played by new antidiabetic drugs in cardiovascular prevention and heart failure. The use of SLGT2i and GLP1a leads to a significant decrease in cardiovascular events, with no difference between the two, except when it comes to hospitalizations for heart failure, where the superiority of the last ones (especially dapaglifozin and empaglifozin) is evident. The current evidence regarding the effect of dpp-4i is diverse, although an increased risk of hospitalizations for heart failure is observed with the use of some drugs of this class (saxagliptin).(AU)