We report on the molecular dynamics simulations of the electrical double layers (EDLs) at the interface of ionic liquids BMIMNO3 and planar electrodes. Simulations confirm that a Helmholtz-like ...interfacial counterion layer exists when the electrode charge density is negative or strongly positive, but the counterion layer is not well-defined when the electrode charge density is weakly positive. The thickness of the EDL, as inferred from how deep the charge separation and orientational ordering of the ions penetrate into the bulk ILs, is about 1.1 nm. The liquid nature of the IL and the short-range ion−electrode and ion−ion interactions are found to significantly affect the structure of the EDL, particularly at low electrode charge densities. Charge delocalization of the ions is found to affect the mean force experienced by the ions and, thus, can play an important role in shaping the EDL structure. The differential capacitance of the EDLs is found to be nearly constant under negative electrode polarization but increases dramatically with the potential under positive electrode polarization. We show that the differential capacitance is a quantitative measure of the response of the EDL structure to a change in electrode charge density. It is found that the NO3− ion dominates the response of EDL structure to the change in electrode charge under both positive and negative electrode polarization, which is qualitatively different from that in aqueous electrolytes. Detailed analysis shows that the cation−anion correlations and the strong adsorption of BMIM+ ions on the electrode are responsible for the capacitance−potential correlation observed here.
Tumour progression allows for aberrant angiogenesis. Consequently, cancer‐associated thrombosis is a prevalent complication that is coupled with poor prognosis. Anticoagulants have therefore been ...prescribed with chemotherapeutic agents to target potential thrombo‐embolic risk. A systematic review was carried out to summarise existing evidence on the interactions between anticoagulants and oral cancer. This treatment paradigm has demonstrated beneficial results in some oncology patients, thus associating anticoagulants with anticancer effects. Increasing prevalence of oral cancer presents a need to source alternative therapeutic means to prevent disease progression, and thus the use of anticoagulants in these patients may provide an avenue for this to occur. The paucity of evidence regarding the interactions between oral squamous cell carcinoma and anticoagulants emphasises the urgency with which further research should be conducted.
Abstract A total of 10,339 positions of the five major Uranian satellites (Ariel, Umbriel, Titania, Oberon and Miranda) were collected at the Yunnan Observatories from 2013 to 2020 with the 1.0 m ...astrometric reflector. A median filtering method was applied to reduce the influence of the bright Uranus halo. All CCD observational data was analyzed by the newly developed CCD image-processing software with Gaia DR3 as the reference catalog. The impact of different exposure times on satellite positioning accuracy was evaluated. The observational positions of satellites were compared with theoretical positions from Institut de Mécanique Céleste et de Calcul des Éphémérides (DE441 and Lainey et al. 2015) and the mean offsets are from −0.″115 to 0.″103 in both R.A. and decl. for the five satellites. The standard deviation of the offsets are from 0.″008 to 0.″086 for the four greatest Uranian satellites and from 0.″037 to 0.″132 for Miranda in each direction. These precise observations of the five major Uranian satellites over an 8 yr period will be very useful for improving the orbital parameters of both Uranus and its five major satellites.
Ion distribution and velocity profiles for electro-osmotic flow in a 3.49 nm wide slit channel with a surface charge density of -0.285 C/m(2) are studied using molecular dynamics simulations. ...Simulation results indicate that the concentration of the co-ion exceeds that of the counterion in the region 0.53 nm away from the channel wall, and the electro-osmotic flow is in the opposite direction to that predicted by the classical continuum theory. The charge inversion is mainly caused by the molecular nature of water and ions. The flow reversal is caused by the immobilization of counterions adsorbed on the channel wall and due to the charge inversion phenomena.
Electroosmotic flow is widely used to transport and mix fluids in micro- and nanofluidic systems. Though essentially all surfaces exhibit certain degrees of roughness, the effects of surface ...roughness on electroosmotic flow is not well-understood. In this paper, we investigate how the electrical double layer and electroosmotic flow are affected by molecular level surface roughness by using molecular dynamics simulations. The simulation results indicate that, when the thickness of the electrical double layer is comparable to the height of surface roughness, presence of sub-nanometer deep concave regions on a rough surface can alter the electrical double layer near the surface, and reduce the electroosmotic flow significantly.PUBLICATION ABSTRACT
We report on the molecular dynamics simulations of electroosmotic flow control by polymer coating. We show that polymer coating modulates the flow by rendering drag to fluids and by changing the ion ...distribution and ion−surface interactions in the electrical double layer. Because of the latter two effects, the polymer coating can even enhance the flow under certain conditions. Identifying the effects of these processes is crucial for the rational design of polymer coating for electroosmotic flow control.
Double-stranded DNA can form efficient hybrid catalysts for asymmetric catalysis upon binding of small metal complexes, which has attracted significant interest. Catalytic microenvironment and chiral ...transfer are still a matter of concern. Here, we introduced peptide nucleic acid (PNA) chains to design oligo-dsPNA and hybrid PNA/DNA as chiral scaffolds to catalyze Friedel–Crafts reaction. Though with the same sequence as DNA control, dsPNA and hybrid duplexes are less suited for use in asymmetric catalysis due to ligand-Cu
2+
complex does not form highly active and enantioselective hybrid catalysts with PNA-containing scaffolds. CD and UV titration assays indicated that the complex bound to suitable groove and the resulting preferential conformation are the key to catalytic performance, rather than just binding affinity.
Graphic Abstract
The negative charge of backbone and the resulting groove size of DNA are the key to act as a more active and highly selective catalyst than PNA.
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