Anti-electrostatic hydrogen bonding between anions of ionic liquids: A density functional theory study

Hydrogen bonds (HBs) play a crucial role in the physicochemical properties of ionic liquids (ILs). At present, HBs between cations and anions (Ca-An) or between cations (Ca-Ca) in ILs have been reported extensively. Here, we provided DFT evidences for the exists of HBs between anions (An-An) in the IL 1-(2-hydroxyethyl)-3-methylimidazolium 4-(2-hydroxyethyl)imidazolide [HEMIm][HEIm]. The thermodynamics stabilities of anionic, cationic, and H2O dimers together with ionic pairs were studied by potential energy scans. The results show that the cation-anion pair is the most stable one, while the HB in anionic dimer possesses similar thermodynamics stability to the water dimer. The further geometric, spectral and electronic structure analyses demonstrate that the inter-anionic HB meets the general theoretical criteria of traditional HBs. The strength order of four HBs in complexes is cation-anion pair > H2O dimer = cationic dimer > anionic dimer. The energy decomposition analysis indicates that induction and dispersion interactions are the crucial factors to overcome strong Coulomb repulsions, forming inter-anionic HBs. Lastly, the presence of inter-anionic HBs in ionic cluster has been confirmed by a global minimum search for a system containing two ionic pairs. Even though hydroxyl-functionalized cations are more likely to form HBs with anions, there still have inter-anionic HBs between hydroxyl groups in the low-lying structures. Our studies broaden the understanding of HBs in ionic liquids and support the recently proposed concept of anti-electrostatic HBs

Mesoporous Mn3O4-CoO core-shell spheres wrapped by carbon nanotubes: a high performance catalyst for the oxygen reduction reaction and CO oxidation

National Natural Science Foundation of China [51173055]; Fundamental Research Funds for the Central Universities [2013QN158]; Research Fund for the Doctoral Program of Higher Education of China [20130142120024]The controllable synthesis of transition metal oxide nanomaterials has attracted considerable attention for the replacement of the current precious metal catalysts. Herein, we have developed a facile method to successfully synthesize Mn3O4-CoO core-shell mesoporous spheres, which are wrapped by carbon nanotubes (CNT), and investigated the catalytic activity for the oxygen reduction reaction (ORR) and CO oxidation for the first time. The ORR process on the Mn3O4-CoO/CNT catalysts was via a complete oxygen reduction process (4e(-)), and the catalytic activity was far better than for the Mn3O4/CNT and CoO/CNT catalysts. The durability even out-performed the commercial Pt/C catalysts. As compared with the Mn3O4/CNT and CoO/CNT catalysts, the Mn3O4-CoO/CNT catalysts also exhibited better catalytic activity for CO oxidation. The initial and complete conversion temperatures for the Mn3O4-CoO/CNT catalysts can decrease to 30 and 120 degrees C, respectively. The good catalytic activity for the ORR and CO oxidation is due to the high specific surface area (138.9 m2 g(-1)) provided which gives many catalytically active sites, mesoporous structure (15 to 120 nm) favoured for molecule accessibility to the active surface of the nanocrystals and mass transport, and the synergistic catalytic effect of Mn3O4 and CoO catalytically active sites

A global view of porcine transcriptome in three tissues from a full-sib pair with extreme phenotypes in growth and fat deposition by paired-end RNA sequencing

<p>Abstract</p> <p>Background</p> <p>Elucidation of the pig transcriptome is essential for interpreting functional elements of the genome and understanding the genetic architecture of complex traits such as fat deposition, metabolism and growth.</p> <p>Results</p> <p>Here we used massive parallel high-throughput RNA sequencing to generate a high-resolution map of the porcine mRNA and miRNA transcriptome in liver, longissimus dorsi and abdominal fat from two full-sib F₂hybrid pigs with segregated phenotypes on growth, blood physiological and biochemical parameters, and fat deposition. We obtained 8,508,418-10,219,332 uniquely mapped reads that covered 78.0% of the current annotated transcripts and identified 48,045-122,931 novel transcript fragments, which constituted 17,085-29,499 novel transcriptional active regions in six tested samples. We found that about 18.8% of the annotated genes showed alternative splicing patterns, and alternative 3' splicing is the most common type of alternative splicing events in pigs. Cross-tissue comparison revealed that many transcriptional events are tissue-differential and related to important biological functions in their corresponding tissues. We also detected a total of 164 potential novel miRNAs, most of which were tissue-specifically identified. Integrated analysis of genome-wide association study and differential gene expression revealed interesting candidate genes for complex traits, such as <it>IGF2, CYP1A1, CKM </it>and <it>CES1 </it>for heart weight, hemoglobin, pork pH value and serum cholesterol, respectively.</p> <p>Conclusions</p> <p>This study provides a global view of the complexity of the pig transcriptome, and gives an extensive new knowledge about alternative splicing, gene boundaries and miRNAs in pigs. Integrated analysis of genome wide association study and differential gene expression allows us to find important candidate genes for porcine complex traits.</p

Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

A Turbidity-Compensation Method for Nitrate Measurement Based on Ultraviolet Difference Spectroscopy

To solve the problem that turbidity in water has a significant effect on the spectra of nitrate and reduces the accuracy of nitrate detection, a turbidity-compensation method for nitrate measurement based on ultraviolet difference spectra is proposed. The effect of turbidity on the absorption spectra of nitrate was studied by using the difference spectra of the mixed solution and a nitrate solution. The results showed that the same turbidity had different effects on the absorbance of different concentrations of nitrate. The change in absorbance due to turbidity decreased with an increase in the nitrate concentration at wavelengths from 200 nm to 230 nm, although this change was constant when the wavelength was greater than 230 nm. On the basis of this characteristic, we combined the residual sum of squares (RSS) and interval partial least squares (iPLS) to select wavelengths of 230&ndash;240 nm as the optimal modeling interval. Furthermore, the turbidity-compensation model was established by the linear fitting of the difference spectra of various levels of turbidity. The absorption spectra of the nitrate were extracted by subtracting the turbidity-compensation curve from the original spectra of the water samples, and the nitrate concentration was calculated by using a partial least squares (PLS)-based nitrate-prediction model. The experimental results showed that the average relative error of the nitrate predictions was reduced by 50.33% to 1.33% by the proposed turbidity-compensation method. This indicated that this method can better correct the deviation in nitrate&rsquo;s absorbance caused by turbidity and improve the accuracy of nitrate predictions

Impact of Land Use Change on the Habitat Quality Evolution in Three Gorges Reservoir Area, China

Habitat quality (HQ) is an important indicator to characterize the level of biodiversity and ecosystem services, and can reflect the quality of the human living environment. Changes in land use can disturb regional HQ. Current research mostly focuses on assessing the good or bad quality of regional habitats, and less on the spatial response relationship between land use change and HQ, and even fewer studies on finely distinguishing the impact of land use types on HQ. Therefore, taking Three Gorges Reservoir Area (TGRA) of China as the study area, this paper first analyzes the land use change of study area by using the land use transfer matrix, land use rate model and landscape pattern index, and then combines the InVEST model with the multi-scale geographically weighted regression (MGWR) model to build a refined assessment framework to quantitatively assess the spatial and temporal evolution patterns of HQ, and then analyse in detail the spatial response relationship of each land use type change on the impact of HQ. The results showed that from 2000 to 2020, the land use in the TGRA shows a changing state of “urban expansion, cultivated land shrinkage, forest land growth, and grassland degradation”. With the change in land use, the habitat quality index (HQI) in the study area showed an “ increase first and then decline” change characteristics, and the HQ degradation was more obvious in the areas with intense human activities. The impact of land use change over the past 20 years on HQ in the TGRA has significant spatial and temporal heterogeneity, with changes in paddy and dryland having mainly negative impacts on HQ, and changes in sparse land, shrubland, and medium-cover grassland having mainly positive impacts on HQ. This paper mainly provides a research framework for refined assessment, and the results can provide scientific support for land planning and ecological protection in the TGRA, and the research methods and ideas can provide references for similar research

EDL structure of ionic liquid-MXene-based supercapacitor and hydrogen bond role on the interface: a molecular dynamics simulation investigation

As a new class of electrodes, MXenes have shown excellent performance in supercapacitors. At the same time, ionic liquid (IL) electrolytes with wider electrochemical windows are expected to substantially increase the supercapacitor capacitance. The combination of MXenes and ILs is promising for energy storage devices with a high energy density and power density. The studies have indicated that the surface terminations of MXenes and the functional groups of ILs, can both strongly influence the supercapacitor's performance. However, studies at the molecular level are still lacking. In this work, we performed molecular dynamics simulations to investigate the interfacial structures and their influence on the energy storage mechanism. The results show that the two ILs exhibit very different charging rates, though the charge densities are similar after charging equilibrium. The interfacial analysis reveals different electrical double-layer (EDL) structures, in which most cations stay perpendicular to the Ti3C2(OH)(2) electrode when some cations shift to a vertical arrangement near the Ti3C2O2 electrode. Such structures have led to the higher capacitance of the Ti3C2(OH)(2) electrode, even more than 2 times that of the Ti3C2O2 electrode as the potential difference ranges from 0 to 2 V. It was also found that hydrogen bonds between the -OH groups of HEMIm(+) cations and terminations of the MXene play an important role in improving the capacitances by aggregating more HEMIm(+) cations on the surface of the Ti3C2(OH)(2) electrode. Our work provides clear mechanistic evidence that both terminations of the MXene electrodes and functional groups of the IL electrolytes affect the interfacial structures and the EDL formation, further leading to the different supercapacitor performance, which will be helpful in designing highly efficient energy-storage devices

Applications of QC and Merged Doppler Spectral Density Data from Ka-Band Cloud Radar to Microphysics Retrieval and Comparison with Airplane in Situ Observation

The new Chinese Ka-band solid-state transmitter cloud radar (CR) uses four operational modes with different pulse widths and coherent integration and non-coherent integration numbers to meet long-term cloud measurement requirements. The CR and an instrument-equipped aircraft were used to observe clouds and precipitation on the east side of Taihang Mountain in Hebei Province in 2018. To resolve the data quality problems caused by attenuation in the precipitation area; we focused on developing an algorithm for attenuation correction based on rain drop size distribution (DSD) retrieved from the merged Doppler spectral density data of the four operational modes following data quality control (QC). After dealiasing Doppler velocity and removal of range sidelobe artifacts; we merged the four types of Doppler spectral density data. Vertical air speed and DSD are retrieved from the merged Doppler spectral density data. Finally, we conducted attenuation correction of Doppler spectral density data and recalculated Doppler moments such as reflectivity; radial velocity; and spectral width. We evaluated the consistencies of reflectivity spectra from the four operational modes and DSD retrieval performance using airborne in situ observation. We drew three conclusions: First, the four operational modes observed similar reflectivity and velocity for clouds and low-velocity solid hydrometeors; however; three times of coherent integration underestimated Doppler reflectivity spectra for velocities greater than 2 m s&minus;1. Reflectivity spectra were also underestimated for low signal-to-noise ratios in the low-sensitivity operational mode. Second, QC successfully dealiased Doppler velocity and removed range sidelobe artifacts; and merging of the reflectivity spectra mitigated the effects of coherent integration and pulse compression on radar data. Lastly, the CR observed similar DSD and liquid water content vertical profiles to airborne in situ observations. Comparing CR and aircraft data yielded uncertainty due to differences in observation space and temporal and spatial resolutions of the data

Eulerian simulation of gas-solid flow in a countercurrent downer

Countercurrent gas-solid downer reactor has been used in various processes, however, fundamental studies on the hydrodynamics of such reactors are sparse, especially, there is no computational fluid dynamics study available. To this end, an empirical inter-phase drag correlation, based on experimental data available in literature, is proposed to address the key role of meso-scale particle clustering structure in determining effective inter-phase drag force. The proposed drag correlation is then integrated into Eulerian model to study the hydrodynamics of gas-solid flow in a countercurrent downer reactor. It was shown that the measured axial pressure distribution and radial solid concentration profiles can be reproduced reasonably well and the radial particle velocity profile can be qualitatively captured as well. Present study offers a preliminary validation of feasibility of modeling gas-solid in a countercurrent downer using Eulerian model. (C) 2013 Elsevier B.V. All rights reserved