Search

Reducing carbon dioxide emissions is one of the possible solutions to prevent global climate change, which is urgently needed for the sustainable development of our society. In this work, easily available, biodegradable amino acid ionic liquids (AAILs) with great potential for CO2 absorption in the manned closed space such as spacecraft, submarines and other manned devices are used as the basic material. Molecular dynamics simulations and ab initio calculations were performed for 12 AAILs ([P4444][X] and [P66614][X], [X] = X = [GLy]−, [Im]−, [Pro]−, [Suc]−, [Lys]−, [Asp]2−), and the dynamic characteristics and the internal mechanism of AAILs to improve CO2 absorption capacity were clarified. Based on structural analysis and the analysis of interaction energy including van der Waals and electrostatic interaction energy, it was revealed that the anion of ionic liquids dominates the interaction between CO2 and AAILs. At the same time, the CO2 absorption capacity of AAILs increases in the order [Asp]2− < [Suc]− < [Lys]− < [Pro]− < [Im]− < [Gly]−. Meanwhile, the synergistic absorption of CO2 by multiple-sites of amino and carboxyl groups in the anion was proved by DFT calculations. These findings show that the anion of AAILs can be an effective factor to regulate the CO2 absorption process, which can also provide guidance for the rational and targeted molecular design of AAILs for CO2 capture, especially in the manned closed space. [ABSTRACT FROM AUTHOR]

Previous studies have reported that as the main extract of areca nut, arecoline (ARE) causes DNA damage and in turn contributes to the carcinogenesis of oral epithelial cells. It has been reported that ARE can inhibit the expression of miR-886-3p. In the current study, we aimed to explore the expression and biological functions of miR-886-3p in oral squamous cell carcinoma (OSCC). Herein, we demonstrated that in OSCC cells treated with ARE, the expression level of miR-886-3p was negatively correlated with the concentration of ARE. Compared with adjacent tissue, the expression level of miR-886-3p in OSCC tissue was remarkably downregulated. Transfection of miR-886-3p mimics markedly decreased viability, migration and invasion of OSCC cells. These experimental data implied that miR-886-3p suppression mediated by ARE took part in the proliferation and metastasis of OSCC. This study can help elucidate the mechanism by which areca nut chewing contributes to the malignant transformation of oral epithelial cells. [ABSTRACT FROM AUTHOR]

As a promising anode material, TiO2(B) has attracted much attention in recent years due to its high power and capacity performances. First-principles calculations are performed here to reveal the electronic properties and the transport of lithium (Li) in the bulk TiO2(B) with and without atomic doping. It is found that a 4-fold coordinated O atom has the lowest formation energy and the smallest bandgap and is the atom that most easily forms an O-vacancy (Ov). In this work, a series of p-type (N, P, As), n-type (F, Cl, Br), and isoelectronic (S, Se, Te) dopants in TiO2(B) are studied. For n-type dopants, the substitution of the F atom has no significant effect on the electronic structure, which results in the lowest formation energy. This result demonstrates that the F atom can provide high intrinsic stability. Analysis of the insertion process of Li in doped TiO2(B) shows that N-doping is the most competitive choice because it not only introduces a lower bandgap of TiO2(B) but it also has the highest binding energy with Li. The advantage of N-doping is derived from the self-compensation effect. Also, three possible transport paths of Li in TiO2(B) were studied via the CI-NEB method. The results show that the energy barrier of all diffusion paths of F doping is lower than that of pure TiO2(B), where path 2 along the b-axis channel has the lowest energy (0.32 eV). This study is expected to shed some light on the electronic structures of TiO2(B) and the transport properties of Li in it. [ABSTRACT FROM AUTHOR]

In this paper, two multicolor CDs have been prepared with eco-friendly folic acid and glucose as precursors by means of a facile hydrothermal strategy. The microscopic and spectroscopic results comprehensively confirmed that both of them exhibited well-defined spherical particles, amorphous structures and similar surface chemistry properties, but with different lateral dimensions and element contents. Moreover, CDs1 and CDs2 show the favorable biocompatibility and low cytotoxicity, in vitro and in vivo CLSM images of HeLa cells and zebrafish larvae tagged with CDs1 and CDs2 revealed multicolor emission (blue, green and red) at different excitation wavelengths. More importantly, the fluorescence of CDs1 could be remarkably enhanced with the increase of Mn2+ concentration in aqueous solution through the bonding of Mn2+ with C–OH and N–H groups on the surface of CDs1. A wide linear range was obtained from 0.5 to 90 μ M with a detection limit of 0.42 μ M. • The CDs with multicolor emission at different excitation were obtained successfully. • The multicolor CDs can be used for living bioimaging. • Mn2+-triggered fluorescence enhancement of the CDs was used for sensing. [ABSTRACT FROM AUTHOR]

Understanding the structural transition of ionic liquids (ILs) confined in a nanospace is imperative for the application of ILs in energy storage, gas separation, and other chemical engineering techniques. In this work, the quantitative relations between the properties and height of the nanochannel (H) for the ([Emim]+[TF2N]−) IL are explored through molecular dynamics simulations. Interestingly, the entropy of the confined IL exhibits a nonmonotonic behavior as H increases: initially increasing for H ＜ 1.0 nm and then decreasing for 1.0 ＜ H ＜ 1.1 nm, followed by increasing again for H ＞ 1.1 nm; it finally approaches that of liquid bulk ILs. The vibrational spectrum of the confined IL is analyzed to investigate the nature of nonmonotonic entropy, showing that the liquidity and partial solidity will be respectively attenuated and enhanced as H decreases from 5.0 to 0.75 nm. Moreover, the hydrogen bond (HB) network and external force are also calculated, showing similar nonmonotonic behaviors when compared with the thermodynamic properties. The entropy gain of the confined IL originates from the reduced HB interactions, weaker external force, and partial solid nature, where more phase space sampling for ILs inside a bilayer graphene nanochannel (BLGC) can be achieved. All the above relations demonstrate that there exists a critical height of the nanochannel (HCR = 1.0 nm) at which the confined IL possesses weaker HB interaction, higher entropy, and better stability. The critical height of the nanochannel is also identified in the analysis of the local structures of cation head groups and anions, indicating that the confined IL could have a faster in-plane diffusive ability. These factors can serve as key indicators in quantitatively characterizing the mechanism for the structural transition of ILs inside a nanochannel and facilitate the rational design of nanopores and nanochannels to regulate the properties and structures of ILs in practical application scenarios. [ABSTRACT FROM AUTHOR]

Carbon-based luminescent materials have attracted much attention of many researchers in recent years for its better optical properties and biological applications. In this paper, we report the full-color CDs (from blue to red) with better quality red emissive by a facile and efficient synthesis route. The CDs show multiple red-emission tuning, unique nature of up-conversion photoluminescent under lower excitation and single-particle photoluminescent. The luminescence mechanism was also explored preliminarily. Especially, the results demonstrate that full-color CDs with multiple red wavelength tuning were achieved successfully by using only one precursor and this phenomenon was reasonably explored by using solvatochromism mechanism instead of only excitation-dependent or emission tuning. Moreover, the multicolor FL emission of CDs is caused by single particles rather than a mixture with diverse photoluminescent, which can be expanded to precision manufacture field on luminance, but not just limited to multidimensions biosensing. In addition, UCPL under lower excitation implies the more important potential applications in surface layer bioimaging, microarray detection and light activation technology in vivo and in vitro. The full-color CDs show high quantum yield (73.89%) and superior anti-photobleaching. Multicolor bioimaging, in vitro and in vivo, indicates its low toxicity in Hela cells and zebrafish. Besides, the as-prepared CDs were successfully used for multidimensions sensing, as Fe3+ metal ion sensing (on/off). [ABSTRACT FROM AUTHOR]

The transmission corridors can be effectively saved using 750 kV four-circuit transmission line on the same tower. In order to reduce the corona level, structure optimisation of fittings plays an important role in the transmission line design. In this study, the electric field distribution of 750 kV transmission line on six cross-arms tower was calculated based on finite element method, and the influences of pipe diameter, ring diameter and installation position of the grading ring were analysed. The results show that the increase of pipe diameter can reduce the electric field strength of grading ring while the increase of installation position and decrease of ring diameter are important to protect the end fitting of composite insulator. When using grading ring with the pipe diameter of 100 mm, the ring diameter of 700–900 mm and the installation position of 150–250 mm, the electric field strength can be controlled in a reasonable range. These results can provide references for the grading ring design of 750 kV four-circuit transmission line on the same tower. [ABSTRACT FROM AUTHOR]

With the rapid development of China's power grid, it is becoming increasingly common that the multi-circuit overhead transmission lines cross over each other. It is important to design the lines' configuration reasonably and evaluate whether the power-frequency electric field meets the national standard. In order to analyse the electric field distribution in the maintenance area of the 220 kV tower with an overhead 1000 kV UHV AC double circuit transmission line, a three-dimensional finite element model of the crossing tower and transmission line was established. The influences of the crossing angle, span height and offset distance on the electric field distribution in the maintenance area of the lower tower and the line worker body surface electric field were analysed. The results show that the maximum electric field strength of the tower will increase 28.7% when the cross-angle decreases from 90° to 30°, and the impact of span height on the electric field distribution is much smaller at 90° than that at 30°. At 60°, when the crossing height is 16 m, the electric field strength on the worker's body surface is much less than the limiting value. [ABSTRACT FROM AUTHOR]

Polysulfides shuttle, although is not the only one, but definitely the most prominent problem which hinders the commercialization of lithium-sulfur cells. Herein, a functionally designed SiO 2 tethered 1-methyl-1-propylpiperidinium chloride (SiO 2 -PPCl) ionic liquid nanoparticle is adopted as a bridgebuilder between the carbon carrier and lithium polysulfides (LPS) to modulate shuttle issues. The SiO 2 -PPCl exerts effective adhesion to both polar LPS and nonpolar carbon carrier material by its special function groups, which make it act as a bridge between them, therefore, the dissolved LPS are prevented from migrating to lithium anode effectively, and the corresponding LPS shuttle is controllable by simply tuning the ratio of SiO 2 -PPCl to sulfur. This strategy is demonstrated in a lithium sulfur suspension flow cell in which the shuttle effect is more serious because large quantity of electrolyte is adopted, and over 1000 cycles is achieved with high coulombic efficiency of 99%. Verified in a laboratory flow cell equipment, the approach of exploiting polysulfides bridgebuilder to control LPS shuttle manifests its feasibility and offers a new direction to develop lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

Ionic liquid (IL) flow in graphene oxide (GO) nanochannels plays a key role in the performance of IL- and GO-based fluidics devices and other chemical separator techniques. Here, we investigate the flow behavior of ILs in GO nanochannels via molecular dynamics simulations. The quantitative relation between slip velocity and shear stress has been identified, showing that the interfacial friction coefficient can be enhanced by almost sixty times, while the slip length is reduced by about three orders of magnitude, with the fraction of hydroxylation in graphene ranging from 0% to 15%. The great change in interfacial properties can be attributed to the structural changes of IL layers near GO, which is proved by the detailed analysis of density distribution, charge distribution and radial distribution function. Besides, the viscosity will increase as a fraction of hydroxylation because of the partial breaking of coulombic ordering of confined ILs. Meanwhile, the hydroxyls have more significant effects on IL flow than water flow in GO nanochannels due to the stronger interaction networks in IL/GO interfaces. In summary, hydroxylation can be a convincing method to regulate the IL flow in nanochannels. The quantitative properties of confined ILs in GO nanochannels and their relation to the fraction of hydroxylation could deepen the understanding of ILs and benefit the applications of ILs and GO in the fields of chemical engineering and various other nanofluidic devices. [ABSTRACT FROM AUTHOR]

Although studies have shown that detection of peripheral circulating tumor cells (CTCs) is an important tool for monitoring prognosis and therapeutic response in patients with cancer, few studies have analyzed their role in patients with hepatocellular carcinoma (HCC) following liver transplantation (LTx). The present study examined whether CTC levels were associated with HCC recurrence in patients with HCC after LTx. This prospective study included 47 patients who received LTx between October 2014 and May 2016 and who underwent analysis for peripheral CTCs at least twice using the CanPatrol system. Baseline Edmondson stage, T stage, accumulated tumor diameter, microvascular cancer embolus, and alpha-fetoprotein (AFP) levels were greater in patients with recurrence (all p<0.05). In addition, 70.2% of patients with HCC were CTC-positive. Although the proportion of CTC subtypes changes following LTx and over the follow-up period with increased epithelial and interstitial CTC levels, no significant associations were observed between change in total CTCs or CTC subtype and HCC recurrence (all p>0.05). In conclusion, baseline Edmondson stage, T stage, accumulated tumor diameter, microvascular cancer embolus, and AFP levels may be predictive of HCC recurrence following LTx; however, CTC levels and subtypes were not. Further large, multicenter studies are necessary to confirm these results. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production via water splitting using metal oxide semiconductors has attract great interests because of the two electrons on the kinetics. Pristine Co 3 O 4 was widely studied as efficient photocatalyst, but prefers to produce oxygen due to its lower band-edge positions with regard to water redox potentials. In this work, high efficient photocatalyst basing on non-noble La doped Co 3 O 4 on graphene, i.e. , La x Co 3-x O 4 /G, were first reported and prepared by the microwave hydrothermal synthesis. In this newly developed hybrids, La and Co ions were adsorbed on the surface of graphene (G) and subsequently reacted with ammonia to yield the La x Co 3-x O 4 /G nanohybrid by in-situ chemical deposition methods. The activity for hydrogen generation of the nanohybrid exhibits 2 times higher than undoped Co 3 O 4 /G under visible light irradiation. The H 2 evolution of nanohybrid reaches 6.543 mmol g −1 h −1 when the molar ratio of La/Co is 10% in the nanohybrid. Our experimental results indicate the incorporation of La doped in the Co 3 O 4 crystal lattice not only forms the lattice defects, resulting in provision for capture trap and the separation of electrons and holes, but also changes the band structure to eventually improve the photocatalytic activity under visible light. Therefore, non-noble La is a promising substitute to prepare highly efficient hydrogen photocatalyst and can be extendedly applied to the other metal oxide semiconductors for solar hydrogen production. [ABSTRACT FROM AUTHOR]