Search

A double-walled MOF with high chemical stability, easy synthesis, and high selectivity for CO2 capture was prepared by ligand modification.

The photocatalyst-free electron donor-acceptor (EDA) complex photochemistry was deemed to expand the potential of photodriven radical chemistry. Here, we report a cross-coupling reaction of thianthrenium salt functionalized arenes and sodium sulfinates via a photopromoted single electron transfer (SET) process of an EDA complex. A series of biarylsulfones were obtained with high site-selectivity and reactivity. This mild and practical radical reaction could be applied on the bioactive and DNA-encoded molecules.

The purpose of this study is to explore the application of eco-wisdom to environmental sustainability. Small-scale eco-wisdom has received much attention in recent years because local practices tend to better reflect the characteristics of the environment. In this study, the texts of the in-depth interviews were coded into three stages to define three sub-categories including flooding disaster, relocation and returning to the homeland, regeneration of the living environment, and six property-dimension including disaster and losses, relocation and returning to the homeland, infrastructure, and agricultural reform. It is found that in the event of natural disasters, residents in the study area accepted and adapted flooding as a survival strategy, developed the ability to observe the environment well, improved the sensitivity of disaster awareness, and carried out agricultural reforms in the coexistence of flooding. These practices jointly shape an environmentally sustainable eco-wisdom.

Highly regioselective conjugate addition of isoxazol-5-ones to ESF gave N2-/C4-alkylated isoxazol-5-ones with a sulfonyl fluoride group in good to excellent yields.

A Rh(iii)-catalyzed migratory insertion of bis(phenylsulfonyl) carbene and α-sulfonyl carbenes into ortho C–H bonds of aryl amides has been developed.

DNA-encoded library (DEL) technology is a powerful tool in the discovery of bioactive probe molecules and drug leads. Mostly, the success in DEL technology stems from the molecular diversity of the chemical libraries. However, the construction of DELs has been restricted by the idiosyncratic needs and the required low concentration (∼1 mM or less) of the library intermediate. Here, we report visible-light-promoted on-DNA radical coupling reactions via an electron donor-acceptor (EDA) complex and a reversible adsorption to solid support (RASS) strategy. This protocol provides a unique solution to the challenges of increasing the reactivity of highly diluted DNA substrates and reducing the residues of heavy metals from photocatalysts. A series of on-DNA indole sulfone and selenide derivatives were obtained with good to quantitative conversions. It is anticipated that these mild-condition on-DNA radical reactions will significantly improve the chemical diversity of DELs and find widespread utility to DEL construction.

The Rh(III)-catalyzed migratory insertion of bis(phenylsulfonyl)carbene into aromatic C-H bonds has been developed. A variety of bis(phenylsulfonyl)methyl derivatives were prepared with good yields under mild conditions. The methylated products were readily obtained after reductive desulfonylation. Furthermore, the diverse transformations of bis(phenylsulfonyl)methyl to trideuteriomethyl, aldehyde, and other functional groups were demonstrated.

Enantioselective conjugate addition of azlactones to ethylene sulfonyl fluoride has been achieved via the cooperative catalysis with (DHQD)2PHAL and a hydrogen-bond donor (HBD). This approach furnishes a facile access to a range of structurally diverse azlactone sulfonyl fluoride derivatives with good to excellent yields and enantioselectivities. The combination of azlactone and sulfonyl fluoride group produces valuable unnatural α-quaternary amino acid derivatives for the drug discovery.

The suppression of types I and III interferon (IFN) responses by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) contributes to the pathogenesis of coronavirus disease 2019 (COVID‐19). The strategy used by SARS‐CoV‐2 to evade antiviral immunity needs further investigation. Here, we reported that SARS‐CoV‐2 ORF9b inhibited types I and III IFN production by targeting multiple molecules of innate antiviral signaling pathways. SARS‐CoV‐2 ORF9b impaired the induction of types I and III IFNs by Sendai virus and poly (I:C). SARS‐CoV‐2 ORF9b inhibited the activation of types I and III IFNs induced by the components of cytosolic dsRNA‐sensing pathways of RIG‐I/MDA5‐MAVS signaling, including RIG‐I, MDA‐5, MAVS, TBK1, and IKKε, rather than IRF3‐5D, which is the active form of IRF3. SARS‐CoV‐2 ORF9b also suppressed the induction of types I and III IFNs by TRIF and STING, which are the adaptor protein of the endosome RNA‐sensing pathway of TLR3‐TRIF signaling and the adaptor protein of the cytosolic DNA‐sensing pathway of cGAS–STING signaling, respectively. A mechanistic analysis revealed that the SARS‐CoV‐2 ORF9b protein interacted with RIG‐I, MDA‐5, MAVS, TRIF, STING, and TBK1 and impeded the phosphorylation and nuclear translocation of IRF3. In addition, SARS‐CoV‐2 ORF9b facilitated the replication of the vesicular stomatitis virus. Therefore, the results showed that SARS‐CoV‐2 ORF9b negatively regulates antiviral immunity and thus facilitates viral replication. This study contributes to our understanding of the molecular mechanism through which SARS‐CoV‐2 impairs antiviral immunity and provides an essential clue to the pathogenesis of COVID‐19.

An enantioselective Michael addition between N-2,2,2-trifluoroethylisatin ketimines and ethylene sulfonyl fluoride has been disclosed. This method provides a facile strategy to access a range of structurally diverse isatin-derived α-(trifluoromethyl)imine derivatives with excellent yields and enantioselectivities. The intriguing combination of α-(trifluoromethyl)amine and sulfonyl fluoride groups leads to the valuable candidates for the drug discovery.

Conjugated porous polymers were successfully synthesized through dynamic covalent condensation polymerization by using aromatic anhydrides and triacylhydrazine benzene. The obtained conjugated polymers with unique chemical stability, high specific surface area and electrochemical active carbonyl functional groups exhibited excellent performance as cathode materials for lithium ion batteries.

This study was to quantitatively investigate the role of morphological and functional parameters of the left atrium (LA) and left atrial appendage (LAA) with 256-slice spiral computed tomography (CT) in the recurrence of atrial fibrillation (AF) after radiofrequency ablation (RFA). Eighty-three patients with AF who underwent RFA for the first time were divided into the recurrence (n = 27) and non-recurrence (n = 56) groups. All patients underwent a 256-slice spiral CT examination before the operation. The clinical data and quantitative measurement of the morphology and functional parameters of the LA and LAA were analyzed, including the maximal and minimal volume, ejection fraction and volume, and volume strain of LAA and LA (LAAVmax, LAAVmin, LAAEF, LAAEV, and LAA-VS, LAVmax, LAVmin, LAEF, LAEV and LA-VS, respectively). The CHA2DS2-VASc score and the proportion of patients with heart failure were significantly (P 9.25 ml had the highest predictive value for AF recurrence after RFA, with the sensitivity of 85.2% and specificity of 67.9%. In conclusion, the volume of left atrium, volume and morphology of left atrial appendage have all significantly increased while the ejection fraction and volume strain of left atrium and left atrial appendage have both significantly decreased in recurrence than in non-recurrence after radiofrequency ablation. The ejection fraction and volume of left atrial appendage are significant independent predictors of atrial fibrillation recurrence after radiofrequency ablation.

A Rh(III)-catalyzed migratory insertion of bis(phenylsulfonyl) carbene and α-sulfonyl carbenes into

A palladium catalyzed reaction of cycloalkanecarboxamides and diazomalonates or bis(phenylsulfonyl)diazomethane has been developed. The reaction proceeds via carbene migratory insertion and cascade C-C cleavage pathways. Cycloalkanecarboxamides with four to seven membered rings are applicable in the transformation. A series of ring opening products were prepared with moderate yields. The finding provides valuable clues for the development of new reactions involving carbene migratory insertion and the cleavage of unstrained C(sp

Strong Rashba effects at semiconductor surfaces and interfaces have attracted great attention for basic scientific exploration and practical applications. Here, we show through first-principles investigation that applying biaxial stress can cause tunable and giant Rashba effects in ultrathin KTaO3 (KTO) (001) films with the most stable surfaces. When increasing the in-plane compressive strain to −5%, the Rashba spin splitting energy reaches ER = 140 meV, corresponding to the Rashba coupling constant αR = 1.3 eV A. We investigate its strain-dependent crystal structures, energy bands, and related properties, and thereby elucidate the mechanism for the giant Rashba effects. Further calculations show that the giant Rashba spin splitting can remain or be enhanced when capping layer and/or Si substrate are added, and a SrTiO3 capping can make the Rashba spin splitting energy reach the record 190 meV. Furthermore, it is elucidated that strong circular photogalvanic effect can be achieved for spin-polarized photocurrents in the KTO thin films or related heterostructures, which is promising for future spintronic and optoelectronic applications.

Three new LnIII-MOFs, {[Dy1.5(TAPB)1.5(DMF)]·9DMF}n (Ln = Dy (1), Er (2), Ho (3); TAPB = 4, 4′, 4″-(triazine‑2, 4, 6‑triyl‑tris‑(benzene‑4, 1-diyl)) tribenzoate), have been synthesized via a solvothermal method by using a trigonal N-containing tricarboxylate as the ligand. The coordination geometries around the central metal ions in the MOFs exhibit different deviations from ideal square antiprism (D4d symmetry) because of the coordinated solvent molecules. The ac magnetic susceptibility data is consistent with single chain magnet behavior for Dy(III) and Er(III) complexes, which have been studied by the noncritical scaling theory.

Novel combined double jet nozzle not only keeps the excellent ability of rotary jet cutting reaming, but also give full play to the strong rock breaking capacity of the Conical single hole jet. In this paper, we use Solid works to complete the modeling of the calculation domain of the combined double jet nozzle, and by using the ANSYS software, the flow field simulation of injector can be realized with the help of The calculation results show that the kernel velocity of novel combined double jet nozzle cylinder end can up to 160 m/s under the working pressure of 60 MPa, at the same time, it can generate large turbulent kinetic energy at the outlet of the nozzle center hole, and the maximum value is 45 m2/s2. The simulation result illustrates that Under the combined action of the center hole jet and the edge hole jet, Novel combined double jet nozzle will produce greater cutting force on the breaking of the rock, and in the radial direction, it will cause a larger area of rock fragmentation.

The origin of orbital order in correlated transition-metal compounds is strongly debated. For the paradigmatic ${e}_{g}$ systems ${\mathrm{KCuF}}_{3}$ and ${\mathrm{LaMnO}}_{3}$, it has been shown that the electronic Kugel'-Khomskii mechanism alone is not sufficient to drive the orbital-ordering transition up to the high temperatures at which it is experimentally observed. In the case of ${t}_{2g}$ compounds, however, the role played by the superexchange interaction remains unclear. Here we investigate this question for two representative systems, the $3d\phantom{\rule{4pt}{0ex}}{t}_{2g}^{1}$ Mott insulators ${\mathrm{LaTiO}}_{3}$ and ${\mathrm{YTiO}}_{3}$. We show that the Kugel'-Khomskii superexchange transition temperature ${T}_{\mathrm{KK}}$ is unexpectedly large, comparable to the value for the ${e}_{g}^{3}$ fluoride ${\mathrm{KCuF}}_{3}$. By deriving the general form of the orbital superexchange Hamiltonian for the ${t}_{2g}^{1}$ configuration, we show that the ${\mathrm{GdFeO}}_{3}$-type distortion plays a key part in enhancing ${T}_{\mathrm{KK}}$ to about 300 K. Still, orbital ordering above 300 K can be ascribed only to the presence of a static crystal-field splitting.

Controlling electronic processes in low-dimension electron systems is centrally important for both fundamental and applied researches. While most of the previous works focused on SrTiO3-based two-dimensional electron gases (2DEGs), here we report on a comprehensive investigation in this regard for amorphous-LaAlO3/KTaO3 2DEGs with the Fermi energy ranging from ∼13 meV to ∼488 meV. The most important observation is the dramatic variation of the Rashba spin–orbit coupling (SOC) as Fermi energy sweeps through 313 meV: The SOC effective field first jumps and then drops, leading to a cusp of ∼2.6 T. Above 313 meV, an additional species of mobile electrons emerges, with a 50-fold enhanced Hall mobility. A relationship between spin relaxation distance and the degree of band filling has been established in a wide range. It indicates that the maximal spin precession length is ∼70.1 nm and the maximal Rashba spin splitting energy is ∼30 meV. Both values are much larger than the previously reported ones. As evidence...

Two polycatenated metal–organic framework materials with different metal centers (Zn2+ for 1 and Cd2+ for 2) were synthesized, which underwent pronounced framework phase transition upon desolvation, and exhibited uncommon temperature-dependent stepwise adsorption and hysteretic desorption of CO2 around room temperature.

A water-stable EuIII-based metal–organic framework (MOF) with dual-emission luminescence behavior, namely {[Eu4(INO)5(μ3-OH)2Cl4(H2O)]·(NO3)·(H2O)5}n (Eu-MOF; HINO = isonicotinic acid N-oxide), was successfully constructed by the solvothermal reaction of Eu3+ ions with the organic ligand HINO. The cationic 3D framework contains microporous channels with accessible Lewis-base sites and NO3− ions as balanced anions, which all contribute to the selective detection of multifarious analytes. This MOF shows ratiometric detection of acetone, Cr2O72− ions, and nitroaromatic compounds (NACs). In particular, it shows great recognition of four NACs in water, representing the first LnIII-MOF which can display distinguishing fluorescence phenomena on NACs rather than relying on the quenching effect. Furthermore, this is also the first example of a MOF-sensor for detecting these explosives discriminatively by ratiometric methods. Additionally, the mechanisms for luminescent responses towards different analytes have been discussed in detail.

Dietary advanced glycation end products (dAGEs) might be potential toxins involved in the pathogenesis of Alzheimer's disease (AD). Quercetin is a flavonoid possessing neuroprotective effects. We aimed to explore whether a 21 days of dAGEs intake would result in cognitive dysfunction in aged ICR mice, and the protective effects of quercetin, with potential mechanisms explored. Fourteen-month old ICR mice were randomly assigned into four groups, that is, Control, AGEs, quercetin, and AGE diet supplemented with quercetin. Key markers involved in Aβ, tau, and neuroinflammation from hippocampus and cortex were measured via western blot. Gut microbiota and short chain fatty acids profiles from intestinal contents were measured via 16S rRNA gene sequencing and gas chromatography (GC), respectively. Quercetin alleviated cognitive impairment induced by dAGEs in aged mice. This might be associated with that quercetin reduced cathepsin B, tau phosphorylation, and neuroinflammation, and elevated α-diversity index (ACE, Chao1, and Shannon index), and reduced phylum Verrucomicrobia of gut microbiota. PRACTICAL APPLICATIONS: Alzheimer's disease (AD) has been regarded as the commonest cause of progressive dementia for the elderly. This study is the very first to demonstrate that even a short-term dietary advanced glycation end product (dAGEs) intake induced impaired cognitive function in aged ICR mice, and querectin is capable of reversing dAGEs-induced cognitive dysfunction. Reduced tau phosphorylation, neuroinflammation, and altered gut microbiota profiles may be involved in querectin's protective effects against dAGEs-induced cognitive impairment. Our study suggested that quercetin supplementation might be beneficial for improving cognitive function in elderly subjects with high consumption of dAGEs such as grilling, frying, and broiling of food.

Structural, electronic, ferroelectric, and optical properties of two-dimensional (2D) BiN monolayer materials with phosphorene-like structure are studied in terms of the density functional theory a...

Background and Purpose— The anterior communicating artery (Acom) aneurysm is the most complex in all cerebral aneurysms, and wider vascular bifurcation angles are considered to be associated with aneurysm formation. The objective of this study was to investigate association of the Acom aneurysm formation with patient age and vascular bifurcation morphology. Methods— Three-dimensional angiographic data of 665 patients were used in this study, including 160 patients with Acom aneurysms, 66 with non-Acom aneurysms, and 439 control subjects with no aneurysms. The anterior cerebral artery bifurcation angle (Acom/A2 angle), arterial diameters, and Acom aneurysm geometric characters were examined. Results— Women of 50 to 70 years were more vulnerable to Acom aneurysm formation than men. The Acom/A2 bifurcation angle was significantly increased ( P< 0.0001) with increase of patient age. The size of the Acom aneurysm dome and neck was statistically positively correlated with the diameter of the Acom, A1 and A2 segments ( P< 0.0001). The Acom/A2 bifurcation angle was significantly ( P< 0.0001) wider in patients with than without Acom aneurysms, whereas the A1/A2 angle was significantly smaller in patients with than without Acom aneurysms ( P< 0.0001). The Acom aneurysms at the bifurcation apex mostly deviated toward the smaller angle formed between the parent A1 and branches and toward the daughter artery with a smaller diameter. The Acom aneurysms were located mostly on the dominant anterior cerebral artery. Conclusions— The presence of Acom aneurysm is significantly associated with patient age, wider angles of the anterior cerebral artery bifurcation, and smaller vascular diameter of the anterior communicating complex.

A facile synthesis of tetraarylpyrazoles has been developed via t- BuOK/DMF promoted intermolecular cycloaddition of hydrazones and 1,2-diarylalkynes. A possible reaction pathway via a hydrazone radical is proposed.

An efficient synthesis of β-alkoxycarbonyl vinylsulfonium salts had been developed. Their reaction with indene-1,3-diones and other active methylene compounds provided cyclopropane carboxylates in good yields. A tentative reaction mechanism was proposed.

Since the discovery of a two-dimensional (2D) electron gas at the LaAlO3/SrTiO3 interface, 2D carrier gases at such oxide interfaces and surfaces have attracted great attention because they can host many important phenomena and may produce novel functional devices. Here, we show through first-principles investigations that the surface 2D electron and hole gases in a KTaO3 (KTO) thin film can be tuned by applying biaxial stress. When increasing compressive in-plane strain, the 2D carrier concentrations decrease down to zero and then a new pair of surface 2D electron and hole gases appears in which the carrier types are switched to the opposite ones. Our analysis indicates that this carrier-type switching occurs because the increasing compressive strain reverses the slope of monolayer-resolved electrostatic potential along the [001] direction. We also present strain-dependent carrier concentrations and effective masses, and explore their thickness dependence. It is further shown that the 2D carrier gases and their strain-driven carrier-type switching across the KTO layer still remain true in the presence of overlayers and epitaxial substrates. These phenomena should be useful to design novel functional devices.

A simple and environmentally friendly strategy for the synthesis of E-ortho-hydroxystilbenes has been established. Two kinds of α,β-unsaturated aromatic lactones, i.e. the 3-arylcoumarins and the isoaurones, could both readily undergo a cascade hydrolyzation/decarboxylation reaction in the presence of KOH in ethylene glycol to afford the desired E-ortho-hydroxystilbenes in moderate to high yields.

Two-dimensional electron gas due to semiconductor interfaces can have high mobility and exhibits superconductivity, magnetism, and other exotic properties that are unexpected in constituent bulk materials. We study crystal structures, electronic states, and magnetism of short-period (BTO)m/(GTO)2 (m=2 and 4) superlattices consisting of insulating BaTiO3 (BTO) and GdTiO3 (GTO) by first principles calculations. Our investigation shows that the middle Ti-O monolayer in the GTO layer becomes metallic. Although both GTO and BTO share a common constituent, the Ti-O atomic layer, the M-O (M=Ba, Ti, and Gd) displacements along the c axis in each monolayer reflect the asymmetry of two interfacial Ti-O monolayers and the large distortion of the TiO6 octahedra in such superlattices, against electronic reconstruction at the interfaces and thus differentially changing the d energy levels of the three Ti-O monolayers related with the GTO layer. Such superlattices are interesting for potential spintronics applications because of their unique asymmetrical two-dimensional electron-gas properties and possible useful spin-orbit effects.

Double perovskite generally exhibits small structure distortion induced by the expansion/contraction and tilting of the BO6 octahedron. It is difficult to precisely determine their structures, particularly the phase with notable pseudo-symmetry structure and two or more phases with slightly different structures. In this paper, the double perovskite Y2CrMnO6 synthesized under high pressure was studied using scanning transmission electron microscopy and first-principles calculations. The new finding is that a rock-salt ordered structure and a layer ordered structure coexist in Y2CrMnO6. Similar to the Cu2+-based compound, this Mn3+-based compound is another new system with layer ordered structure. Unlike the structures of YCrO3 and YMnO3, the ordered structure of Y2CrMnO6 displays half-metal characteristics.

A palladium-catalyzed coupling reaction of bis(phenylsulfonyl)methane and aryl halides was developed. A variety of bis(phenylsulfonyl)methyl arenes were prepared in good yields. The transformations of bis(phenylsulfonyl)methyl to methyl, trideuteriomethyl, ethyl, carboxyl, and other functional groups were demonstrated. The results provided a new approach to diverse functionalization of aryl halides.

Two-dimensional electron gas (2DEG) at the perovskite oxide interface exhibits a lot of exotic properties, presenting a promising platform for the exploration of emergent phenomena. While most of the previous works focused on SrTiO3-based 2DEG, here we report on the fabrication of high-quality 2DEGs by growing an amorphous LaAlO3 layer on a (001)-orientated KTaO3 substrate, which is a 5d metal oxide with a polar surface, at a high temperature that is usually adopted for crystalline LaAlO3. Metallic 2DEGs with a Hall mobility as high as ∼2150 cm2/(V s) and a sheet carrier density as low as 2 × 1012 cm–2 are obtained. For the first time, the gating effect on the transport process is studied, and its influence on spin relaxation and inelastic and elastic scattering is determined. Remarkably, the spin relaxation time can be strongly tuned by a back gate. It is reduced by a factor of ∼69 while the gate voltage is swept from −25 to +100 V. The mechanism that dominates the spin relaxation is elucidated.