Activity

5). AuNRs coated by polymethacrylate with pendant mPEG (PPEGMA-AuNRs) without surface charge transition activities were used for comparison. PCB-AuNRs presented better antimicrobial activity against Gram-negative bacteria (E. coli), Gram-positive bacteria (S. aureus) and their drug-resistant strains (MRSA and EBSL E. coli) than PPEGMA-AuNRs as a result of their pH-responsive surface charge transition activities. Moreover, PCB-AuNRs demonstrated deeper penetration into mature biofilms and better biofilm elimination activities than their non-surface charge-transformable counterparts. The results indicate that the designed zwitterion-coated AuNRs are a promising antibacterial agent for fighting bacterial infections.Over the past two decades, electrospinning has emerged as an enabling nanotechnology to produce nanofiber materials for various biomedical applications. In particular, therapeutic/cellloaded nanofiber scaffolds have been widely examined in drug delivery, wound healing, and tissue repair and regeneration. However, due to the insufficient porosity, small pore size, noninjectability, and inaccurate spatial control in nanofibers of scaffolds, many efforts have been devoted to exploring new forms of nanofiber materials including expanded nanofiber scaffolds, nanofiber aerogels, short nanofibers, and nanofiber microspheres. This short review discusses the preparation and potential biomedical applications of new forms of nanofiber materials.Intramolecular Kinugasa reactions on in situ generated carbohydrate-derived alkynylnitrones are described. The effects of the length of chains, their mutual configuration, influence of experimental conditions on product distribution and feasibility of the β-lactam ring construction were studied. Intramolecular reactions proceed with high stereoselectivity to provide in each case one product only. The cycloadducts from tartaric acid were converted into the corresponding non-racemic 4-acetoxy azetidinones in good yields.The interaction of pinanediol with 2-fluorophenylboronic acid and several other substituted phenylboronic acids was studied in 40% vol. aqueous acetonitrile by 1H and 11B NMR, potentiometric and spectrophotometric titrations at variable pH values. The experimental results reveal the formation of a very stable trigonal ester (Ktrig ≈ 2 × 104 M-1) and a significantly less stable tetrahedral hydroxocomplex (Ktet ≈ 5 × 103 M-1) in contrast to the traditionally observed inverted order of stabilities Ktrig Ktet is observed in spite of the existence of the usual strain release effect in the O-B-O angle considered responsible for the typically observed increased stability of the tetrahedral hydroxocomplex. A complementary study of the stability of the six-membered cyclic boronate esters of chromotropic acid demonstrated the order Ktrig ≪ Ktet although the strain was absent in these esters. The results for m-, p-substituted phenylboronic acids show that the stability of both five- and six-membered trigonal esters formed with pinanediol and chromotropic acid, respectively, is insensitive to electronic effects but the electron accepting substituents stabilize the hydroxocomplexes. It follows from the whole set of results that Ktet can be much larger than Ktrig in the absence of the strain, but with a sufficiently acidic diol, and that the presence of the strain does not necessarily make Ktet larger than Ktrig for a less acidic diol with a purely saturated hydrocarbon backbone. Thus, the electronic effects manifested in the acidity of the diol appear to be more significant than the strain release effect in determining the Ktet/Ktrig ratio.Central-radial bi-porous nanocatalysts were synthesized by derivation from dendritic porous supports with hierarchical inorganic functional layers. The nanostructure exhibited a high unit loading capacity, accessible internal catalytic sites and protective mesoporous shell encapsulation. The nanocatalysts were utilized for efficient and stable heterogeneous catalytic reduction of 4-nitrophenol to 4-aminophenol with robust magnetic recyclability.Two hexagold diphosphine-stabilized [(P,P)4Au6]2+ molecular nanoclusters with the same [core + exo] arrangement differing in the linker (phenylene or trimethylene) connecting the two P-donor sites have been subjected to theoretical studies with the aim of shedding light on two main questions. On one hand, from a previous study [J. Vícha, C. Foroutan-Nejadand M. Straka,Nat. Commun., 2019, 10, 1643], it is still unclear whether short C-H2Au contacts revealed in the corresponding crystal structures are just forced by bulky P(Ph)2 groups and, on the other hand, to what extent the linker affects the visible band position [M. A. Bakar, M. Sugiuchi, M. Iwasaki, Y. Shichibuand K. Konishi, Nat. Commun., 2017, 8, 576]. Here, it is demonstrated that even in simpler model systems in which bulky groups were replaced by PH2 groups, C-H2Au hydrogen bonding interactions are retained and show comparable values, as measured by NBO and QTAIM analyses, to those of 1 and 2. These analyses further confirmed a stronger HB in 1 than in 2. Also, the comparison of model systems without and with a linker connecting the phosphine groups showed a bathochromic shift of 47 and 60 nm, revealing the key role of the linker. The Δρ(r)EE-GS plots of 1 and 2 revealed electron density depletion in the inter-nuclear C-H2 region upon electronic transition unveiling its contribution to their optical properties.Correction for ‘Red-emitting phosphors APF6Mn4+ (A = Cs+, Rb+, K+) synthesis, luminescence properties and application in solid-state lighting’ by Yu Chen et al., Dalton Trans., 2019, 48, 10901-10906.A multifunctional chemical neural probe fabrication process exploiting PDMS thin-film transfer to incorporate a microfluidic channel onto a silicon-based microelectrode array (MEA) platform, and enzyme microstamping to provide multi-analyte detection is described. The Si/PDMS hybrid chemtrode, modified with a nano-based on-probe IrOx reference electrode, was validated in brain phantoms and in rat brain.Liver and other tissues accumulate selenium (Se) when animals are supplemented with high dietary Se as inorganic Se. To further study selenometabolites in Se-deficient, Se-adequate, and high-Se liver, turkey poults were fed 0, 0.4, and 5 μg Se g-1 diet as Na2SeO3 (Se(iv)) in a Se-deficient (0.005 μg Se g-1) diet for 28 days, and the effects of Se status determined using HPLC-ICP-MS and HPLC-ESI-MS/MS. No selenomethionine (SeMet) was detected in liver in turkeys fed either this true Se-deficient diet or supplemented with inorganic Se, showing that turkeys cannot synthesize SeMet de novo from inorganic Se. Selenocysteine (Sec) was also below the level of detection in Se-deficient liver, as expected in animals with negligible selenoprotein levels. Sec content in high Se liver only doubled as compared to Se-adequate liver, indicating that the 6-fold increase in liver Se was not due to increases in selenoproteins. What increased dramatically in high Se liver were low molecular weight (MW) selenometabolites glutathione-, cysteine- and methyl-conjugates of the selenosugar, seleno-N-acetyl galactosamine (SeGalNac). Substantial Se in Se-adequate liver was present as selenosugars decorating general proteins via mixed-disulfide bonds. In high-Se liver, these “selenosugar-decorated” proteins comprised ∼50% of the Se in the water-soluble fraction, in addition to low MW selenometabolites. In summary, more Se is present as the selenosugar moiety in Se-adequate liver, mostly decorating general proteins, than is present as Sec in selenoproteins. With high Se supplementation, increased selenosugar formation occurs, further increasing selenosugar-decorated proteins, but also increasing selenosugar linked to low MW thiols.A family of mononuclear penta-coordinated CoII complexes, [Co(L)Cl2]·CH3OH (1), [Co(L)Br2] (2) and [Co(L)(NCS)2] (3) (where L is 1-mesityl-N,N-bis(pyridin-2-ylmethyl)methanamine) were synthesized and characterized. In these complexes, the neutral non-planar ligand, L, binds to three coordination sites around the metal center while two others are bound by anionic halide/pseudo halide ligands. The coordination geometry of the complexes is dictated by the coordinated anionic ligands. Thus, the coordination geometry around the metal ion is distorted trigonal bipyramidal for complexes 1 and 3, while it is distorted square pyramidal for complex 2. Ab initio CASSCF/NEVPT2 calculations on the complexes reveal the presence of an easy plane magnetic anisotropy with the D and E/D values being, 13.3 and 0.14 cm-1 for 1; 36.1 and 0.24 cm-1 for 2 and ±8.6 and 0.32 cm-1 for 3. mTOR kinase assay These values are in good agreement with the values that were extracted from the experimental DC data. AC magnetic measurements reveal the presence of a field-induced slow relaxation of magnetization. However, clear maxima in the out-of-phase susceptibility curves were not observed for 1 and 3. For complex 2, peak maxima were observed when the measurements were carried out under an applied field of 1400 Oe which allowed an analysis of the dynamics of the slow relaxation of magnetization. This revealed that the relaxation is mainly controlled by the Raman and direct processes with the values of the parameters found to be B = 0.77(15) s-1 K-6.35, n = 6.35(12) and A = 3.41(4) × 10-10 s-1 Oe-4 K-1 and m = 4 (fixed). The ab initio calculation which showed the multifunctional nature of the electronic states of the complexes justifies the absence of zero-field SIM behaviour of the complexes. The magnitude and sign of the D and E values and their relationship with the covalency of the metal-ligand bonds was analysed by the CASSCF/NEVPT2 as well as AILFT calculations.The discovery of novel catalytic materials is predicated on understanding contemporary synthetic processes. With this fundamental knowledge in place it becomes possible to modify the final material with subtle changes to the synthesis process. In this vein, hierarchical materials, formed by the addition of a mesoporogen within the hydrothermal synthesis, have attracted a significant amount of attention due to their catalytic benefits over analogous microporous species. In this work we monitor the hydrothermal synthesis in situ of a hierarchical and a microporous aluminophosphate, for the first time, combining total scattering and pairwise distribution function data. In doing so we observe the local formation of the species, and the longer range crystallisation processes concurrently.An efficient, selective and scalable C-H amidation of s-tetrazines under iridium(III) catalysis is reported. This reaction features a broad substrate scope, high functional group tolerance, and air and water tolerance. This reaction also shows great potential for the rapid preparation of tri- and tetra-functional building blocks, which can be applied either in bioconjugation or synthesis of DNA-encoded library.Recent reviews have highlighted the use of perylenediimides (PDIs) as non-fullerene acceptors in bulk-heterojunction organic photovoltaic devices. This review is focused on the advances in the incorporation of PDIs as photoactive components in different solar cell devices. An impressive number of perylenediimides have been incorporated into p-n organic solar cells, as non-fullerene acceptors in bulk heterojunction solar cells, as photosensitisers in dye-sensitised solar cells, in perovskite solar cells, and also as interlayers acting as either electron- or hole-transporting materials. All of this has led to devices with outstanding photovoltaic performance and these are described in this review.