Sloanworm5436

Finally, using a simplified wave form, we investigated the influence of phase and frequency differences, intrinsic curvature and wave amplitude on the swimming trajectory of flagellar apparatus. Our analysis shows that by controlling the phase or frequency differences between two flagella, steering can occur.Thermoplastic elastomers based on ABA triblock copolymers are typically limited in modulus and strength due to crack propagation within the brittle regions when the hard end-block composition favors morphologies that exhibit connected domains. Increasing the threshold end-block composition to achieve enhanced mechanical performance is possible by increasing the number of junctions or bridging points per chain, but these copolymer characteristics also tend to increase the complexity of the synthesis. Here, we report an in situ polymerization method to successfully increase the number of effective junctions per chain through grafting of poly(styrene) (PS) to a commercial thermoplastic elastomer, poly(styrene)-poly(butadiene)-poly(styrene) (SBS). The strategy described here transforms a linear SBS triblock copolymer-styrene mixture into a linear-comb-linear architecture in which poly(styrene) (PS) grafts from the mid-poly(butadiene) (PBD) block during the polymerization of styrene. Through systematic variation in the initial SBS/styrene content, nanostructural transitions from disordered spheres to lamellar through reaction-induced phase transitions (RIPT) were identified as the styrene content increased. Surprisingly, maximum mechanical performance (Young's modulus, tensile strength, and elongation at break) was obtained with samples exhibiting lamellar nanostructures, corresponding to overall PS contents of 61-77 wt% PS (including the original PS in SBS). The PS grafting from the PBD block increases the modulus and the strength of the thermoplastic elastomer while preventing brittle fracture due to the greater number of junctions afforded by the PS grafts. The work presented here demonstrates the use of RIPT to transform standard SBS materials into polymer systems with enhanced mechanical properties.Two-dimensional (2D) van der Waals (vdW) heterostructures, known as layer-by-layer stacked 2D materials in a precisely chosen sequence, have received more and more attention in spintronics for their ultra-clean interface, unique electronic properties and 2D ferromagnetism. Motivated by the recent synthesis of monolayer 1T-VSe2 with ferromagnetic ordering and a high Curie temperature above room temperature, we investigate the bias-voltage driven spin transport properties of 2D magnetic tunnel junctions (MTJs) based on VSe2 utilizing density functional theory combined with the nonequilibrium Green's function method. In the device 1T-MoSe2/1T-VSe2/2H-WSe2/1T-VSe2/1T-MoSe2, the tunneling magneto-resistance (TMR) is incredibly satisfactory up to 5600%. Based on the analysis of evanescent states, this large TMR is attributed to the spin filter effect at the interface between 1T-VSe2 and 2H-WSe2, which overcomes the low spin polarization of 1T-VSe2. Furthermore, by inserting 2H-MoSe2, the spin filter effect is enhanced with decreasing current and the TMR is drastically improved to 1.7 × 105%. This work highlights the feasibility of 2D vdW heterostructures for ultra-low power spintronic applications by electronic structural engineering.Recently, sunscreen-based drug photocages have been introduced to provide UV protection to photoactive drugs, thus increasing their photosafety. Here, combined experimental and theoretical studies performed on a photocage based on the commercial UVA filter avobenzone (AB) and on the photosensitizing non-steroidal anti-inflammatory drug ketoprofen (KP) are presented unveiling the photophysical processes responsible for the light-triggered release. Particular attention is paid to solvent stabilization of the drug and UV filter excited states, respectively, which leads to a switching between the triplet excited state energies of the AB and KP units. Most notably, we show that the stabilization of the AB triplet excited state in ethanol solution is the key requirement for an efficient photouncaging. By contrast, in apolar solvents, in particular hexane, KP has the lowest triplet excited state, hence acting as an energy acceptor quenching the AB triplet manifold, thus inhibiting the desired photoreaction.Interactions of the analgesic medications dextropropoxyphene (DPP, opioid), paracetamol (PCL, nonnarcotic), tramadol (TDL, nonnarcotic), ibuprofen (IBN, nonsteroidal anti-inflammatory drug (NSAID)), and naproxen (NPX, NSAID) with pristine graphene (GN) and nitrogen-doped GN (NGN; containing only graphitic N atoms) nanosheets were explored using density functional theory (DFT) in the gas and aqueous phases. Calculations in the aqueous phase were performed using the integral equation formalism polarized continuum model (IEFPCM). Calculated geometry-optimized structures, partial atomic charges (determined using Natural Bond Orbital analysis), highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps, work functions (determined using time-dependent DFT), and molecular electrostatic potential plots showed that the adsorption process is physical in nature (viz. physisorption), primarily due to noncovalent π-π and van der Waals interactions. In addition, calculated adsorption eynamically favorable. In addition, generally, analgesic/NGN complexes exhibit higher adsorption affinities and solvation energies in the gas and aqueous phases. Therefore, GN and NGN nanosheets are potential adsorbents for extracting analgesic contaminants from aqueous environments such as aquatic ecosystems.We study the individual and combined influence of TMAO and urea on a basket-type DNA G-quadruplex by means of atomistic molecular dynamics (MD) simulations. In combination with the Kirkwood-Buff theory of solutions, we propose a simple mechanism to elucidate the impact of TMAO and urea on the G-quadruplex. Our results reveal the importance of the molecular accumulation around the DNA in terms of stabilizing or destabilizing effects. The results for mixtures show only a weak interaction between both co-solutes, which highlights the additivity of contributions. Despite the fact, that TMAO can to some extent compensate the adverse impact of urea on the G-quadruplex structure, the destabilizing influence is not completely eliminated. This observation opens the door for further research on selective stabilization of DNA G-quadruplexes by modulating the concentrations of TMAO and urea in solution.A chiral vesicle system with photo-regulated chiroptical properties including Cotton effects and circularly polarized luminescence (CPL) was reported. Photoresponsive cyanostilbene was conjugated to the cholesteryl group, which provides chiral centers and lipophilic domain for the flexible vesicle membrane formation. The building block self-assembled into vesicles with exciton Cotton effects and CPL. The high dissymmetry g-factor of CPL at 10-2 order of magnitude was achieved. Upon UV light irradiation, Cotton effects were enhanced with an elevated g-factor by 3-fold, while the CPL dissymmetry factor showed a light irradiation resistance. A hydrophobic fluorescent dye (Nile Red) was loaded into vesicle membranes to allow energy transfer and chirality transfer to give red color CPL with retained high g-factor, while resistance to the UV light irradiation of vesicles was enhanced after loading the fluorescent dye. This study highlights the fabrication of the chiral vesicle system with noninvasively stimulus-responsive chiroptical properties, which may provide new thoughts for the fabrication of smart chiroptical materials in aqueous media.In the scientific endeavor to understand the chemical origins of life, the photochemistry of the smallest life building blocks, nucleobases, has been a constant object of focus and intense research. Here, we report the results of the first theoretical study on the photo-properties of an 8-oxo-hypoxanthine molecule, the chromophore of 8-oxo-inosine, which is relevant to the recently proposed, prebiotically plausible synthetic routes to the formation of purine- and pyrimidine-nucleotides. With ab initio and semi-empirical OM2/MRCI quantum-chemistry calculations, we predict a strong photostability of the 8-oxo-hypoxanthine system and see the origin of this effect in ultrafast nonradiative relaxation through puckering of the 6-membered heterocyclic ring.Intrinsically disordered proteins (IDPs) play important roles in cellular functions. The inherent structural heterogeneity of IDPs makes the high-resolution experimental characterization of IDPs extremely difficult. Molecular dynamics (MD) simulation could provide the atomic-level description of the structural and dynamic properties of IDPs. This perspective reviews the recent progress in atomic MD simulation studies of IDPs, including the development of force fields and sampling methods, as well as applications in IDP-involved protein-protein interactions. The employment of large-scale simulations and advanced sampling techniques allows more accurate estimation of the thermodynamics and kinetics of IDP-mediated protein interactions, and the holistic landscape of the binding process of IDPs is emerging.The reaction between two equivalents of (Me3Si)2CH(Ph)PH(BH3) (1) and Bu2Mg, followed by two equivalents of BH3·SMe2, gives the corresponding phosphido-bis(borane) complex, which may be crystallised as two distinct chemical species the complex [(Me3Si)2CH(Ph)P(BH3)2]2Mg(THF)4·THF (2a), and two different THF solvates (1  1 and 1  2) of the solvent-separated ion triples [(Me3Si)2CH(Ph)P(BH3)2]2[Mg(THF)6]·THF (2b) and [(Me3Si)2CH(Ph)P(BH3)2]2[Mg(THF)6]·2THF (2c). Similar reactions between two equivalents of 1 and either (4-tBuC6H4CH2)2Ca(THF)4 or [(Me3Si)2CH]2Sr(THF)2, followed by two equivalents of BH3·SMe2, give the heavier alkali metal complexes [(Me3Si)2CH(Ph)P(BH3)2]2M(THF)4 [M = Ca (3), Sr (4)]. Surprisingly, compounds 2a, 3 and 4 adopt almost identical structures in the solid state, which differ only in the geometrical arrangement of the phosphido-bis(borane) ligands and the hapticity of the borane groups.Alkali metal ion beyond lithium based energy storage systems have recently attracted increasing attention due to their unique advantages of high natural abundance and low cost. Herein, we report the fabrication of P,N-codoped carbon mesoporous nanotubes (denoted as PNC-MeNTs) through a facile two-step strategy with MnO2 nanowires as a dual-function sacrificing template, where the in situ oxidative polymerization formation of pyrrole-aniline-phytic acid composite nanotubes and a subsequent carbonization treatment are involved. The PNC-MeNTs exhibit outstanding electrochemical performance for both Na+ and K+ storage, respectively, where high specific capacities of 287.2 mA h g-1 and 219.6 mA h g-1 at 0.1 A g-1 and remarkable cycling stability over 10 000 cycles at 10 A g-1 and 3000 cycles at 1 A g-1 can be achieved. More importantly, potassium-ion hybrid capacitors with a PNC-MeNT anode and an activated carbon cathode can deliver remarkable energy/power density of 175.1 W h kg-1/160.6 W kg-1, as well as a long cycling life.