Evolution of organic phosphor through precision regulation of nonradiative decay.

Development of single-component organic phosphor attracts increasing interest due to its wide applications in optoelectronic technologies. Theoretically, activating efficient intersystem crossing (ISC) via 1(π, π*) to 3(π, π*) transitions, rather than 1(n, π*) → 3(π, π*) transitions, is an alternative access to purely organic phosphors but remains challenging. Herein, we designed and successfully synthesized the sila-8-membered ring fused biaryl benzoskeleton by transition metal catalysis, which served as a new organic phosphor with efficient 1(π, π*) to 3(π, π*) ISC. We first found that such a compound exhibits a record-long phosphorescence lifetime of 6.5 s at low temperature for single-component organic systems. Then, we developed two strategies to tune their decay channels to evolve such nonemissive molecules into bright phosphors with elongated lifetimes at room temperature: 1) Physic-based design, where quantitative analyses of electron-phonon coupling led us to reveal and hinder the major nonradiative channels, thus lighted up room temperature phosphorescence (RTP) with a lifetime of 480 ms at 298 K; 2) chemical geometry-driven molecular engineering, where a geometry-based descriptor ΔΘT1-S0/ΘS0 was developed for rational screening RTP candidates and further improved the RTP lifetime to 794 ms. This study clearly shows the power of interdiscipline among synthetic methodology, physics-based rational design, and computational modeling, which represents a paradigm for the development of an organic emitter.

MAC mediates mammary duct epithelial cell injury in plasma cell mastitis and granulomatous mastitis.

Plasma cell mastitis (PCM) and granulomatous mastitis (GM) are common inflammatory nonbacterial mastitis (NBM). However, the pathogenesis of NBM is still unclear. METHODS: In this study, we statistically analyzed the pathological features of PCM and GM using pathological HE staining and tissue transmission electron microscopy. The levels of MAC (C5b-9n), P-selectin, E-selectin, and ICAM-1 were detected through IHC, WB, ELISA, and qPCR. The expression level and location of MAC were observed by tissue immunological electron microscopy. In addition, exosomes were isolated from tissues, identified using transmission electron microscopy, and the densities were detected by Nano-FCM. Finally, the expression intensity of MAC in exosomes was detected by flow cytometry and immunoelectron microscopy. RESULTS: The damage and apoptosis of mammary duct epithelial cells are the common pathological features of PCM and GM. MAC is primarily located in the cell membrane of mammary ductal epithelial cells and is significantly expressed in PCM and GM. The density of exosomes in PCM and GM tissues was elevated, and MAC was highly expressed in exosomes. In addition, the expression of P-selectin, E-selectin, and ICAM-1 in PCM and GM was significantly higher than in the normal group. CONCLUSION: We found severe damage of the mammary duct epithelial cells in PCM and GM tissues, which was verified by relevant pathological methods. Earlier studies demonstrated that MAC is highly expressed in PCM and GM tissues and exosomes seem to play a very important role in the understanding of MAC. Furthermore, MAC is involved in inflammatory infiltration and lesion of mammary duct epithelial cells upregulated by P-selectin, E-selectin, and ICAM-1. These findings provide new insights into PCM and GM molecular mechanisms.

Nickel(0)-catalyzed divergent reactions of silacyclobutanes with internal alkynes.

Transition metal-catalyzed reactions of silacyclobutanes with a variety of π units have attracted much attention and become one of the most straightforward and efficient approaches to rapidly access structurally diverse organosilicon compounds. However, the reaction of silacyclobutanes with alkynes still suffers from some limitations: (1) internal alkynes remain challenging substrates; (2) expensive Pd- or Rh-based catalysts have been employed in all existing systems; (3) controlling chemodivergence has not yet been realized. Herein we realize Ni-catalyzed chemodivergent reactions of silacyclobutanes with alkynes. In comparison with the previous Pd or Rh catalytic systems, our Ni-catalytic system features: 1) complementary substrate scope; 2) ligand-controlled chemodivergence; 3) low cost. The ligand precisely dictates the pathway selectivity, leading to the divergent formation of (benzo)silacyclohexenes and allyl vinylsilanes. Moreover, we demonstrate that employment of a chiral phosphine ligand is capable of forming silicon-stereogenic allyl vinylsilanes in high yields and enantioselectivities. In addition, DFT calculation is performed to elucidate the origin of the switchable selectivities, which is mainly attributed to different ligand steric effects.

Bis-silylation of internal alkynes enabled by Ni(0) catalysis.

1,2-Bis-silyl alkenes have exciting synthetic potential for programmable sequential synthesis via manipulation of the two vicinal silyl groups. Transition metal-catalyzed bis-silylation of alkynes with disilanes is the most straightforward strategy to access such useful building blocks. However, this process has some limitations: (1) symmetric disilanes are frequently employed in most of the reactions to assemble two identical silyl groups, which makes chemoselective differentiation for stepwise downstream transformations difficult; (2) the main catalysts are low-valent platinum group transition metal complexes, which are expensive; and (3) internal alkynes remain challenging substrates with low inherent reactivity. Thus, the development of abundant metal-catalyzed bis-silylation of internal alkynes with unsymmetrical disilanes is of significance. Herein, we solve most of the aforementioned limitations in bis-silylation of unsaturated bonds by developing a strongly coordinating disilane reagent and a Ni(0) catalytic system. Importantly, we sufficiently realize the stepwise recognition of the two silyl groups, making this synthetic protocol of wide potential utility.

Enantioselective Catalytic Aldehyde α-Alkylation/Semipinacol Rearrangement: Construction of α-Quaternary-δ-Carbonyl Cycloketones and Total Synthesis of (+)-Cerapicol.

An enantioselective aldehyde α-alkylation/semipinacol rearrangement was achieved through organo-SOMO catalysis. The catalytically generated enamine radical cation serves as a carbon radical electrophile that can stereoselectively add to the alkene of an allylic alcohol and initiate ensuing ring-expansion of cyclopropanol or cyclobutanol. This tandem reaction enables the production of a wide range of nonracemic functionalizable α-quaternary-δ-carbonyl cycloketones in high yields and excellent enantioselectivity from simple aldehydes and allylic alcohols. As a key step, the intramolecular reaction was also successfully applied in the asymmetric total synthesis of (+)-cerapicol.

Effects of Porphyromonas gingivalis lipopolysaccharide on osteoblast-osteoclast bidirectional EphB4-EphrinB2 signaling.

In bone remodeling, the Eph family is involved in regulating the process of osteoclast and osteoblast coordination in order to maintain bone homeostasis. In this study, the effects of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) on the osteoblast-osteoclast bidirectional EphB4-EphrinB2 signaling were investigated. An osteoblast-osteoclast co-culture system was achieved successfully. Hence, direct contact and communication between osteoblasts and osteoclasts was permitted. Regarding the protein expression and gene expression of EphB4 and EphrinB2, it was shown that Pg-LPS increased the expression of EphB4 while inhibiting the expression of EphrinB2. Therefore, the results indicate that, when treated with Pg-LPS, the EphB4 receptor on osteoblasts and the EphrinB2 ligand on osteoclasts may generate bidirectional anti-osteoclastogenic and pro-osteoblastogenic signaling into respective cells and potentially facilitate the transition from bone resorption to bone formation. This study may contribute to the control of osteoblast differentiation and bone formation at remodeling, and possibly also modeling, sites.

Continuous blood purification ameliorates RhoA-mediated endothelial permeability in severe acute pancreatitis patients with lung injury.

BACKGROUND: In the early phase of severe acute pancreatitis (SAP), serious pulmonary complications which are directly correlated with mortality are very common. Endothelial injury has been shown to play a key role in the pathogenesis of ALI/ARDS. Continuous blood purification (CBP) has been widely used in treating patients with multiple organ dysfunction syndrome (MODS) including ARDS. However, the impact of CBP on endothelial function has been little studied. METHODS: Human umbilical vein endothelial cells (HUVECs) were exposed to serum samples or replacement fluid taken from patients at specific time points during CBP, or pretreated with Y-27632 followed by treatment with serum, then, changes in cytoskeletal configuration, endothelial monolayer permeability, and RhoA activation were studied. RESULTS: Endothelial permeability, RhoA activity, and stress fiber reorganization increased in HUVECs treated with serum from patients before CBP initiation, and lessened in HUVECs treated with serum from patients after CBP initiation. Endothelial hyperpermeability and stress fiber reorganization reduced in HUVECs pretreated with Rho-kinase inhibitor, Y-27632, and in a dose-dependent fashion. Endothelial permeability and RhoA activity increased in HUVECs treated with waste replacement fluid collected 2 h after CBP initiation. CONCLUSIONS: After CBP treatment, endothelial hyperpermeability induced by serum from SAP patients with lung injury was reduced. The inhibition of RhoA-mediated F-actin remodeling might be the mechanism.