Photoinduced elimination of senescent microglia cells in vivo by chiral gold nanoparticles

Parkinson''s disease (PD) is an age-related neurodegenerative disease, and the removal of senescent cells has been proved to be beneficial for improving age-associated pathologies in neurodegeneration disease. In this study, chiral gold nanoparticles (NPs) with different helical directions were synthesized to selectively induce the apoptosis of senescent cells under light illumination. By modifying anti-B2MG and anti-DCR2 antibodies, senescent microglia cells could be cleared by chiral NPs without damaging the activities of normal cells under illumination. Notably, l-P⁺ NPs exhibited about a 2-fold higher elimination efficiency than d-P⁻ NPs for senescent microglia cells. Mechanistic studies revealed that the clearance of senescent cells was mediated by the activation of the Fas signaling pathway. The in vivo injection of chiral NPs successfully confirmed that the elimination of senescent microglia cells in the brain could further alleviate the symptoms of PD mice in which the alpha-synuclein (α-syn) in cerebrospinal fluid (CFS) decreased from 83.83 ± 4.76 ng mL⁻¹ to 8.66 ± 1.79 ng mL⁻¹ after two months of treatment. Our findings suggest a potential strategy to selectively eliminate senescent cells using chiral nanomaterials and offer a promising strategy for alleviating PD.

The apoptosis pathways of senescent microglia cells induced by chiral NPs under the irradiation of 808 nm laser in the brain of PD mice.     

Transferrable selectivity profiles enable prediction in synergistic catalyst space

Organometallic intermediates participate in many multi-catalytic enantioselective transformations directed by a chiral catalyst, but the requirement of optimizing two catalyst components is a significant barrier to widely adopting this approach for chiral molecule synthesis. Algorithms can potentially accelerate the screening process by developing quantitative structure–function relationships from large experimental datasets. However, the chemical data available in this catalyst space is limited. Herein, we report a data-driven strategy that effectively translates selectivity relationships trained on enantioselectivity outcomes derived from one catalyst reaction systems where an abundance of data exists, to synergistic catalyst space. We describe three case studies involving different modes of catalysis (Brønsted acid, chiral anion, and secondary amine) that substantiate the prospect of this approach to predict and elucidate selectivity in reactions where more than one catalyst is involved. Ultimately, the success in applying our approach to diverse areas of asymmetric catalysis implies that this general workflow should find broad use in the study and development of new enantioselective, multi-catalytic processes.

Statistical models can be applied to predict and develop enantioselective reactions involving two catalysts.     

Chemical constituents of pericarps of Rosa davurica Pall., a traditional Chinese medicine

From pericarps of Rosa davurica (Rosaceae), a traditional Chinese medicine, eight known tetracyclic triterpene acids, three known flavonoids, ethyl beta-fructopyranoside and methyl 3-O-beta-glucopyranosyl-gallate were isolated.     

Wash-free magnetic oligonucleotide probes-based NMR sensor for detecting the Hg ion

An easily applied and sensitive sensor for the detection of heavy metal ion residues based entirely on magnetic nanoparticle and oligonucleotide was developed. The tool is established on the relaxation of magnetic nanoparticles with different dispersion states. The target analyte, Hg ions, induce the aggregation of the MNP oligonucleotide probes. Accordingly, the light produced by the magnetic relaxation image and the transverse relaxation time (T(2)) all change due to the effect of the aggregation. The limit of qualitative detection of the sensor is 0.15 ppt. The recoveries from test samples range between 97.1-101.8%. Using the nuclear resonance instrument, the method is a high throughput and sensitive sensor.     

Probing the structural and magnetic properties of transition metal-benzene anion complexes

Two types of transition metal-benzene anion complexes, (titanium)(n)(benzene)(m)? and (cobalt)(n)(benzene)(m)? (n ≤ 2, m ≤ 3) have been determined using density functional theory. The photoelectron spectra of Ti(n)Bz(m)? and Co(n)Bz(m)? (n ≤ 2, m ≤ 3) were discussed from the perspective of quantum chemical calculations of the vertical detachment energies (VDEs) of several low-energy isomers obtained by the structural optimization procedure. The binding of Ti and Co atoms to benzene molecules is accounted by 3d-π bonds, as revealed by the molecular orbitals. The topology of the electronic density has been analyzed, suggesting that the C-C bonds were weakened in the transition metal-benzene complexes in comparison to those in free benzene. Spin density distribution results show the spin densities for Ti(n)Bz(m)? and Co(n)Bz(m)? (n ≤ 2, m ≤ 3) reside mainly on the metal Ti and Co centers (70%-90%). A shift to lower magnetic moment with respect to the pure titanium/cobalt cluster anions indicates the solvent benzene molecule acts to demagnetize the bare titanium/cobalt cluster anions.     

Synthesis and structural characterization of Cu(I) and Ni(II) complexes that contain the bis[2-(diphenylphosphino)phenyl]ether ligand. Novel emission properties for the Cu(I) species

The pseudotetrahedral complexes [Cu(NN)(DPEphos)]BF(4), where DPEphos = bis[2-(diphenylphosphino)phenyl]ether and NN = 1,10-phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), 2,9-di-n-butylphenanthroline (3), or two dimethylcyanamides (4), and NiCl(2)(DPEphos) (5) have been synthesized and structurally characterized by X-ray crystallography and their solution properties examined by use of a combination of cyclic voltammetry, NMR spectroscopy, and electronic absorption spectroscopy. Complexes 1-4 possess a reversible Cu(II)/Cu(I) couple at potentials upward of +1.2 V versus Ag/AgCl. Compounds 1-3 exhibit extraordinary photophysical properties. In room-temperature dichloromethane solution, the charge-transfer excited state of the dmp (dbp) derivative exhibits an emission quantum yield of 0.15 (0.16) and an excited-state lifetime of 14.3 mus (16.1 mus). Coordinating solvents quench the charge-transfer emission to a degree, but the photoexcited dmp complex 2 retains a lifetime of over a microsecond in acetone, methanol, and acetonitrile.     

Facile and quick synthesis of 1-monosubstituted aryl 1,2,3-triazoles: a copper-free [3+2] cycloaddition

An efficient copper-free synthesis of 1-monosubstituted aryl 1,2,3-triazoles from sodium acetylide and aryl azides was developed, which was found suitable for various aryl azides and completed within 15 min at room temperature with moderate to excellent yields.     

铱(Ⅳ)-高碘酸钾-二安替比林对氯苯基甲烷新体系催化光度法测定痕量铱

研究发现在磷酸介质中,痕量铱(Ⅳ)对高碘酸钾氧化二安替比林对氯苯基甲烷(DApCM)的显色反应具有明显的催化作用。找到了反应的最佳条件,并测定了一些动力学参数,据此建立了测定痕量铱(Ⅳ)的新方法。其检出限为2.11×10~(-9) g/mL;Ir(Ⅳ)的线性范围为0～20μg/L,用于矿样中痕量铱的测定,结果满意。     

New norditerpenoids from Cespitularia hypotentaculata

Four new norditerpenoids, designated as cespihypotins A (1), B (2), C (3) and D (4), were isolated from Cespitularia hypotentaculata Roxas (Xeniidae) that was collected in Taiwan. Compounds 1 and 2 are unprecedented structures having 13- and 14-membered lactone ring, respectively. Their structures were elucidated on the basis of extensive spectroscopic analysis. A plausible biogenetic pathway for compounds 1-4 was also proposed.     

Bandgap engineering of SrTiO3/NaTaO3 heterojunction for visible light photocatalysis

Hybrid density functional of HSE06 has been adopted to investigate the geometry and electronic properties of SrTiO₃/NaTaO₃ heterostructures in contrast with the cubic SrTiO₃ and cubic NaTaO₃. The SrTiO₃/NaTaO₃ heterostructures with varied monolayers of SrTiO₃ and NaTaO₃ units are constructed, and all the heterojunction systems have the smaller bandgaps as compared with those of pure SrTiO₃ and NaTaO₃. For the (SrTiO₃)_m/(NaTaO₃)_n (m + n = 10) systems, the bandgap decreases in the order of m = 1, 2, 3, 4, 5, while the bandgap increases in the order of m = 5, 6, 7, 8, 9. We also investigate the (SrTiO₃)_m/(NaTaO₃)_m systems (m = 1, 2, 3, 4, 5, 6, 7), and the calculated results suggest that the (SrTiO₃)₆/(NaTaO₃)₆ system has the smallest bandgap of 2.58 eV in our considered systems. This study indicates the development of SrTiO₃/NaTaO₃ heterojunction is a promising way to improve the photocatalytic activities of SrTiO₃ and NaTaO₃.