88 research outputs found
High-performance electrochemical CO2 reduction cells based on non-noble metal catalysts
The promise and challenge of electrochemical mitigation of CO2 calls for innovations on both catalyst and reactor levels. In this work, enabled by our high-performance and earth-abundant CO2 electroreduction catalyst materials, we developed alkaline microflow electrolytic cells for energy-efficient, selective, fast, and durable CO2 conversion to CO and HCOO-. With a cobalt phthalocyanine-based cathode catalyst, the CO-selective cell starts to operate at a 0.26 V overpotential and reaches a Faradaic efficiency of 94% and a partial current density of 31 mA/cm2 at a 0.56 V overpotential. With a SnO2-based cathode catalyst, the HCOO--selective cell starts to operate at a 0.76 V overpotential and reaches a Faradaic efficiency of 82% and a partial current density of 113 mA/cm2 at a 1.36 V overpotential. In contrast to previous studies, we found that the overpotential reduction from using the alkaline electrolyte is mostly contributed by a pH gradient near the cathode surface
Field-Assisted Splitting of Pure Water Based on Deep-Sub-Debye-Length Nanogap Electrochemical Cells
Owing to the low conductivity of
pure water, using an electrolyte
is common for achieving efficient water electrolysis. In this paper,
we have fundamentally broken through this common sense by using deep-sub-Debye-length
nanogap electrochemical cells to achieve efficient electrolysis of
pure water (without any added electrolyte) at room temperature. A
field-assisted effect resulted from overlapped electrical double layers
can greatly enhance water molecules ionization and mass transport,
leading to electron-transfer limited reactions. We have named this
process âvirtual breakdown mechanismâ (which is completely
different from traditional mechanisms) that couples the two half-reactions
together, greatly reducing the energy losses arising from ion transport.
This fundamental discovery has been theoretically discussed in this
paper and experimentally demonstrated in a group of electrochemical
cells with nanogaps between two electrodes down to 37 nm. On the basis
of our nanogap electrochemical cells, the electrolysis current density
from pure water can be significantly larger than that from 1 mol/L
sodium hydroxide solution, indicating the much better performance
of pure water splitting as a potential for on-demand clean hydrogen
production
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Joint Indirect Standardization When Only Marginal Distributions are Observed in the Index Population
<p>It is a common interest in medicine to determine whether a hospital meets a benchmark created from an aggregate reference population, after accounting for differences in distributions of multiple covariates. Due to the difficulties of collecting individual-level data, however, it is often the case that only marginal distributions of the covariates are available, making covariate-adjusted comparison challenging. We propose and evaluate a novel approach for conducting indirect standardization when only marginal covariate distributions of the studied hospital are known, but complete information is available for the reference hospitals. We do this with the aid of two existing methods: iterative proportional fit, which estimates the cells of a contingency table when only marginal sums are known, and synthetic control methods, which create a counterfactual control group using a weighted combination of potential control groups. The proper application of these existing methods for indirect standardization would require accounting for the statistical uncertainties induced by a situation where no individual-level data are collected from the studied population. We address this need with a novel method which uses a random Dirichlet parameterization of the synthetic control weights to estimate uncertainty intervals for the standard incidence ratio. We demonstrate our novel methods by estimating hospital-level standardized incidence ratios for comparing the adjusted probability of computed tomography examinations with high radiations doses, relative to a reference standard and we evaluate out methods in a simulation study. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.</p
Additional file 1 of LncRNA ZFAS1 protects chondrocytes from IL-1β-induced apoptosis and extracellular matrix degradation via regulating miR-7-5p/FLRT2 axis
Additional file 1: Table S1. The sequences of oligonucleotides and primer
Additional file 3 of LncRNA ZFAS1 protects chondrocytes from IL-1β-induced apoptosis and extracellular matrix degradation via regulating miR-7-5p/FLRT2 axis
Additional file 3: Table S2. The list of the down-regulated genes in GSE11060
Additional file 2 of LncRNA ZFAS1 protects chondrocytes from IL-1β-induced apoptosis and extracellular matrix degradation via regulating miR-7-5p/FLRT2 axis
Additional file 2: Figure S1. lncRNAs expression changes in chondrocytes treated with IL-1β. AâD The expression levels of four lncRNAs were determined by qRT-PCR analysis. The chondrocytes were treated with 10 ng/mL IL-1β for 24 h. **Pâ<â0.01, compared with the control grou
A counter-flow-based dual-electrolyte protocol for multiple electrochemical applications
This paper reports a computational demonstration and analysis of an innovative counter-flow-based microfluidic unit and its upscaling network, which is compatible with previously developed dual-electrolyte protocols and numerous other electrochemical applications. This design consists of multidimensional T-shaped microchannels that allow the effective formation of primary and secondary counter-flow patterns, which are beneficial for both high-performance regenerative H 2 /O 2 redox cells and flow batteries at a low electrolyte flow-rate operation. This novel design demonstrates the potential to achieve high overall energy throughput and reactivity because of the full utilization of all available reaction sites. A computational study on energy and pressure loss mechanism during scale-out is also examined, thereby advancing the realization of an economical electrolyte-recycling scheme
Prediction of Bubble Size Distribution above the Bubble-Breaking Plate
The chord length distribution (CLD) of bubbles in the
region above
the bubble-breaking plate in the scrubbingâcooling chamber
was studied experimentally using a conductivity probe. The predictive
correlations of the shape parameters were established by fitting the
CLD with a distribution function. The bubble shape was discussed,
and the CLD was analytically converted to the size distribution of
the direct contact of the probe. The results showed that the CLD has
specific right-skewed characteristics, and the Rayleigh distribution
has the best-fitting effect on the CLD. The correlation equation of
the shape parameter k of the Rayleigh distribution
concerning the Fr number, local gas holdup Îľg, and dimensionless radius r/R was established. The predicted bubble size distributions (BSDs)
based on ellipsoids are in good morphological agreement with the experimental
size distributions. The relative error between the calculated and
experimental values of the gasâliquid interface area was within
Âą20%, which verified the accuracy of the prediction of the BSD
Ursolic Acid and Oleanolic Acid Dissolved in Methanol/Acetone + Water Blends: Thermodynamic Solubility, Intermolecular Interactions, and Solvation Behavior
With the purpose of qualitative characterization
of the electrostatic
properties of the acidity and basicity of ursolic acid (UA) and oleanolic
acid (OA), quantitative analyses of the molecular surface were employed
in this contribution. The âOH and âCOOH groups on the
molecules of OA and UA took precedence over establishing hydrogen
bonds with the solvents acetone/methanol/water. In addition, the intermolecular
interactions of OA and UA with acetone/methanol/water were investigated
using an independent gradient model based on the Hirshfeld partition
of molecular density. In solutions of OA/UA dissolved in methanol/acetone/water,
attractive interactions, including the hydrogen-bond force and van
der Waals (vdW) force, occur. The shake-flask technique was applied
to evaluate the equilibrium solubility of UA and OA in acetone + water
and methanol + water at 101.2 kPa and elevated temperatures covering
from 278.15 to 323.15 K. Solventâsolvent interactions accounted
by the solubility parameter of solutions had a significant domination
in the variability of solubility magnitudes. The vanât HoffâJouybanâAcree,
Apelblat, and JouybanâAcree models revealed a good correlation
for the measured solubility, with a relative mean deviation of no
more than 7.73%. The KirkwoodâBuff integral approach was utilized
to determine the preferred solvation of UA and OA by solvent species.
In both the rich- and intermediate-composition regions of methanol/acetone,
UA or OA is preferentially solvated with positive preferential solvation
parameters by methanol/acetone
Data_Sheet_1_The effect of cognitive reappraisal and expression suppression on sadness and the recognition of sad scenes: An event-related potential study.docx
Previous studies have found differences in the cognitive and neural mechanisms between cognitive reappraisal and expression suppression in the regulation of various negative emotions and the recognition of regulated stimuli. However, whether these differences are valid for sadness remains unclear. As such, we investigated the effect of cognitive reappraisal and expression suppression on sadness regulation and the recognition of sad scenes adopting event-related potentials (ERPs). Twenty-eight healthy undergraduate and graduate students took part in this study. In the regulation phase, the participants were asked to down-regulation, expressive suppression, or maintain their sad emotion evoked by the sad images, and then to perform an immediately unexpected recognition task involving the regulated images. The behavioral results show that down-regulation reappraisal significantly diminished subjective feelings of sadness, but expressive suppression did not; both strategies impaired the participantsâ recognition of sad images, and expressive suppression had a greater damaging effect on the recognition of sad images than down-regulation reappraisal. The ERP results indicate that reappraisal (from 300 ms to 1,500 ms after image onset) and expressive suppression (during 300â600 ms) significantly reduced the late positive potential (LPP) induced by sadness. These findings suggest that down-regulation reappraisal and expression suppression can effectively decrease sadness, and that down-regulation reappraisal (relative to expression suppression) is a more effective regulation strategy for sadness. Both strategies impair the recognition of sad scenes, and expression suppression (compared to down-regulation reappraisal) leads to relatively greater impairment in the recognition of sad scenes.</p
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