Otteadcock8193

In this article, we have systematically explored the electronic, optical and thermoelectric properties of tetragonal germanene (T-Ge) using first principles calculations. The ground state geometry of pristine T-Ge is buckled and exhibits nodal line semi-metallic behaviour. In addition, we have proposed a tight binding (TB) model Hamiltonian that efficiently explains the emergence of double Dirac points at the Fermi level of T-Ge. Furthermore, a hopping relation has been explored at which both Dirac points merge and then annihilate resulting in a direct band gap at the Γ point. To exploit the buckling of the system, we have employed a transverse electric field, which invariably breaks the sublattice symmetry and removes the degeneracies at the Fermi surface. Furthermore, the band gap at the Dirac points varies linearly with the external electric field strength. Our TB Hamiltonian adequately satisfies the first principles results even in the presence of an external electric field. Moreover, we have found that T-Ge offers efficient tuning of band gaps at the Dirac points compared to other buckled systems viz. hexagonal silicene and germanene. In addition, the optical behaviour of T-Ge has been explained in accordance with the electronic states of the system. The strong optical responses in a low energy region make the material efficient for optical nanodevice applications. Moreover, T-Ge shows relatively better thermoelectric behaviour than graphene. Therefore, the external electric field induced tunable band gap and intriguing low energy optical signals pave the way to choose T-Ge as a smart choice for optoelectronic device applications. Finally we have suggested probable routes for experimental realization of the T-Ge structure.Highly diastereoselective methods for the synthesis of two different diastereomers of polynuclear dispiroheterocyclic compounds with five chiral centers comprising pyrrolidinyloxindole and imidazothiazolotriazine moieties (dispiro[imidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazine-7,3'-pyrrolidine-2',3-indoles]) have been developed on the basis of a dipolar cycloaddition of azomethine ylides to benzylidene derivatives of imidazothiazolotriazines and an alkali-induced rearrangement of the thiazolotriazine fragment. The different sequence of the cycloaddition and rearrangement stages allows us to perform the targeted synthesis of two diastereomerically pure products from the same starting compounds.Introducing macromolecular micelles into a biocompatible hyaluronic acid (HA) hydrogel is a promising strategy to improve its mechanical properties for biomedical applications. selleck screening library However, it is still unclear whether the solvent nature has an influence on the structure and property of HA gels especially when they are used for those cases containing binary solvents because reversible hydrophobic association within micelles could be weakened or even dissociated by organic solvents. In this work, we demonstrated that a binary solvent consisting of water and low-toxic dimethyl sulfoxide (DMSO), a commonly used cryoprotectant agent in biomedicine, can enhance the mechanical properties of hydrophobic-associated methacrylated hyaluronate (MeHA) gels crosslinked by diacrylated PEO99-PPO65-PEO99 (F127DA) macromolecular micelles, namely FH gels. The resulting FH hydro/organo-gels showed a crystalline structure due to polymer/solvent interactions. The FH gels showed a low swelling degree and the maximum strength (10.12 MPa), modulus (106.8 kPa) and toughness (1540 J m-2) in DMSO with a volume fraction of around 0.6. Moreover, the FH gels displayed a rapid recoverability under cyclic loading-unloading stress particularly in the presence of DMSO within the network due to their dual-dynamic dissipation networks. Such novel hydrophobic associated polysaccharide gels with tunable mechanical properties in binary solvents would be attractive in a cryopreservation system for cell-based applications.Herein, we report the synthesis of calix[4]resorcinarene-based multivalent ligands bearing β-S-GlcNAc and β-S-AllNAc recognition elements. A clickable β-S-AllNAc derivative was successfully prepared from a β-thioalkynyl GlcNAc precursor, making use of a 2,3-oxazoline intermediate, easily formed by intramolecular displacement of a triflate group located at the 3-position by the 2-N-acetate group. By reaction of these alkynyl-functionalized derivatives with an octaazido-calix[4]resorcinarene macrocycle having undecyl chains, two octavalent glycoclusters exposing the epimeric N-acetylhexosamines were obtained. In addition, a related calix[4]resorcinarene-based glycocluster having methyl groups instead of undecyl chains and β-S-GlcNAc residues was also synthesized. After an initial evaluation of the interaction of the undecyl-functionalized β-S-GlcNAc octavalent derivative with Wheat Germ Agglutinin (WGA) by a turbidimetry experiment, the interaction of the three synthesized glycoclusters towards WGA was studied by Isothermal Titration Calorimetry. The results showed a favorable effect due to the presence of the undecyl chains in terms of affinity. Surprisingly, the β-S-AllNAc octavalent compound showed the highest affinity among the evaluated glycoclusters, showing for the first time that WGA interacts with β-AllNAc-bearing ligands. Molecular docking studies of β-AllNAc with WGA in comparison with β-GlcNAc contributed to the understanding of the atomic interactions responsible for this unexpected affinity.A bifunctional cholic acid-bis(2-pyridylmethyl)amine (bpa) ligand featuring an amide linker was coordinated to a manganese(i) or rhenium(i) tricarbonyl moiety to give [M(bpacholamide)(CO)3] with M = Mn, Re in good yield and very high purity. Strong antibacterial activity was observed against four strains of methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus, with minimum inhibitory concentrations (MICs) in the range of 2-3.5 μM. No difference in response was observed for the MSSA vs. MRSA strains. Activity was also independent of the nature of the metal center, as the Mn and Re complexes showed essentially identical MIC values. In contrast to some other metal carbonyl complexes, the activity seems to be unrelated to the release of carbon monoxide, as photoactivation of the Mn complex reduced the potency by a factor of 2-8. Both metal complexes were non-toxic in Galleria mellonella larvae at concentrations of up to 100× the MIC value. In vivo testing in Galleria larvae infected with MRSA/MSSA demonstrated a significant increase in overall survival rates from 46% in the control to 88% in the group treated with the metal complexes.