Waughalbert4976

The precise control over high-order DNA architecture assembly might be challenging due to complicated circuit design and functional unit synthesis. Here, we show an enzyme-free, catalytic assembly to construct nanometer and micrometer architectures in a bottom-up manner and applied them in nanoparticles and cell assembly.Transformation of triple helicene (TH) to double helicene (DH) with adjacent stereogenic carbon atoms and axial stereogenicity was achieved by the unexpected conjugate addition to the central aromatic ring of TH-1. We also studied the boundary at which different reactivities to addition reactions occur in some helicenes with different π-extension.We provide the first benchmark characterization of the OH- + CH3CH2Y [Y = F, Cl, Br, I] reactions utilizing the high-level explicitly-correlated CCSD(T)-F12b method with the aug-cc-pVnZ [n = 2(D), 3(T), 4(Q)] basis sets. We explore and analyze the stationary points of the elimination (E2) and substitution (SN2) reactions, including anti-E2, syn-E2, back-side attack, front-side attack, and double inversion. In all cases, SN2 is thermodynamically more preferred than E2. In the entrance channel of SN2 a significant front-side complex formation is revealed, and in the product channel the global minimum of the title reactions is obtained at the hydrogen-bonded CH3CH2OHY- complex. Similar to the OH- + CH3Y reactions, double inversion can proceed via a notably lower-energy pathway than front-side attack, moreover, for Y = I double inversion becomes barrier-less. For the transition state of the anti-E2, a prominent ZPE effect emerges, giving an opportunity for a kinetically more favored pathway than back-side attack. In addition to SN2 and E2, other possible product channels are considered, and in most cases, the benchmark reaction enthalpies are in excellent agreement with the experimental data.Polymer architecture is an important factor in polymer mechanochemistry. In this Feature Article, we summarize recent developments in utilizing polymer architecture to modulate mechanochemical reactions within polymers, or more specifically, the location and rates of bond scission events that lead to polymer fragmentation or mechanophore activation. Various well-defined architectures have been explored, including those of cyclic, intramolecularly cross-linked, dendritic, star, bottlebrush, and dendronized polymers. Selleckchem JAK inhibitor We primarily focus on describing the enhancement or suppression of mechanochemical reactivity, with respect to analogous linear polymers, as well as differences in solution- and solid-state behavior.Nowadays, chronic diseases have become a potential danger to human health and are highly concerning. Given that pigs are a suitable animal model for human nutrition and metabolism for its similar anatomical and physiological properties to those of humans, this study has used 24 castrated male Duroc × Landrace × Yorkshire (DLY) pigs as experimental subjects to explore the effects of dietary dihydromyricetin (DHM) supplementation on the antioxidant capacity and lipid metabolism. Results showed that dietary 300 and 500 mg DHM kg-1 diet supplementation increased the serum total superoxide dismutase (T-SOD) level, serum and liver reduced glutathione (GSH), muscle catalase (CAT) level and serum high-density lipoprotein cholesterol (HDL-C) level, and reduced the liver malondialdehyde (MDA) level and muscle triglyceride (TG) level in finishing pigs. Western blot analysis showed that dietary DHM supplementation activated the nuclear-related factor 2 (Nrf2) and AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signals. Real-time quantitative PCR analysis showed that dietary DHM supplementation upregulated the mRNA levels of lipolysis and fatty acid oxidation-related genes, and down-regulated the mRNA expression of lipogenesis-related genes in finishing pigs. Together, we provide evidence that dietary DHM supplementation improved the antioxidant capacity and lipid metabolism in finishing pigs.Inspired by the chemistry and biology of hexahydroxanthones, herein we report an organocatalytic Michael-Michael-Aldol-decarboxylation reaction that provides efficient access to biologically interesting fully substituted hexahydroxanthones bearing six contiguous stereogenic centers from readily accessible materials in acceptable yields (up to 63%) and excellent stereoselectivities (up to 10  1 dr and >99% ee). In other words, the reaction efficiently produces three chemical bonds and up to six vicinal stereogenic centers in a one-pot operation. In particular, to our knowledge, this is an asymmetric organocatalytic strategy enabling the first construction of six vicinal stereogenic centers on non-spirocyclic hexahydroxanthone frameworks.A 3D zinc-organic hybrid [Zn3(D-Cam)3(tib)2]·2H2O (1) exhibits triple-mode dependent (including excitation wavelength, time and temperature) long-persistent luminescence. Experimental and theoretical calculations support that the long lifetime and color-tunable afterglow may be due to the dispersive electronic state distribution. Furthermore, the hybrid is also used for optical anti-counterfeiting and information encryption applications.Carbon isotope labeling is a traceless technology, which allows tracking the fate of organic compounds either in the environment or in living organisms. This article reports on a general approach to label urea derivatives with all carbon isotopes, including 14C and 11C, based on a Staudinger aza-Wittig sequence. It provides access to all aliphatic/aromatic urea combinations.The sensitive determination of selenium and copper is of importance for environmental monitoring and food safety. A stripping voltammetric determination of selenium and copper in water and selenium-rich foods was developed using hierarchical dendritic gold nanostructure (AuHD) modified glassy carbon electrodes (GCE). The AuHD thin films were electrodeposited potentiostatically onto the GCE from a solution containing 25 mM HAuCl4 and 0.1 M Na2SO4 at -0.6 V for 20 min. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) studies showed that the electrodeposited gold thin film shows a nanoforest-like morphology with a thickness of about 30-40 μm and a hierarchical dendritic structure with primary-, secondary-, and higher-order branches. Se(iv) and Cu(ii) in a 0.1 M H2SO4 solution were determined by square-wave anodic stripping voltammetry using the AuHDs/GCE as the working electrode. Prior to anodic stripping, Se(iv) and Cu(ii) were accumulated onto the working electrode surface at -0.