Photon upconversion of near-infrared (NIR) irradiation into ultraviolet-C (UVC) emission offers many exciting opportunities for drug release in deep tissues, photodynamic therapy, solid-state lasing, energy storage, and photocatalysis. However, NIR-to-UVC upconversion remains a daunting challenge due to low quantum efficiency. Here, we report an unusual six-photon upconversion process in Gd3+/Tm3+-codoped nanoparticles following a heterogeneous core-multishell architecture. This design efficiently suppresses energy consumption induced by interior energy traps, maximizes cascade sensitizations of the NIR excitation, and promotes upconverted UVC emission from high-lying excited states. We realized the intense six-photon-upconverted UV emissions at 253 nm under 808 nm excitation. This work provides insight into mechanistic understanding of the upconversion process within the heterogeneous architecture, while offering exciting opportunities for developing nanoscale UVC emitters that can be remotely controlled through deep tissues upon NIR illumination.
HMG-CoA reductase (HMGCR) protein is usually upregulated after statin (HMGCR inhibitor) treatment, which inevitably diminishes its therapeutic efficacy, provoking the need for higher doses associated with adverse effects. The proteolysis targeting chimera (PROTAC) technology has recently emerged as a powerful approach for inducing protein degradation. Nonetheless, due to their bifunctional nature, developing orally bioavailable PROTACs remains a great challenge. Herein, we identified a powerful HMGCR-targeted PROTAC ( 21c ) comprising a VHL ligand conjugated to lovastatin acid that potently degrades HMGCR in Insig-silenced HepG2 cells (DC 50 = 120 nmol/L) and forms a stable ternary complex, as predicated by a holistic modeling protocol. Most importantly, oral administration of the corresponding lactone 21b reveled favorable plasma exposures referring to both the parent 21b and the conversed acid 21c . Further in vivo studies of 21b demonstrated robust HMGCR degradation and potent cholesterol reduction in mice with diet-induced hypercholesterolemia, highlighting a promising strategy for treating hyperlipidemia and associated diseases.
lasers, [5] single-mode lasers, [6] continuouswave lasers, [7] polariton lasers, [8] and laser arrays. [9] Halide perovskites have also been widely studied in photocatalytic organic reaction, [10] photocatalytic CO 2 reduction, [11] and photocatalytic hydrogen evolution. [12] Due to their broad technological importance, halide perovskites have become the focus of current research.Recently, ferroelectricity has been detected in halide perovskites and quickly attracted widespread interest. [13] Ferroelectricity is a characteristic of spontaneous polarization in certain materials, which can be reversed by applying an external electric field. The discovery of ferroelectricity can be traced back to 1920 [14] (Figure 1a), when Valasek measured the polarization of Rochelle Salt as a function of the applied electric field. Perovskite ferroelectric first appeared on the scene in the early 1940s [15] (Figure 1b). Up to now, perovskite oxides (e.g., BaTiO 3 , [16] PbZr x Ti 1−x O 3 , [17] Bi 4−x La x Ti 3 O 12 , [18] LiNbO 3 , [19] and LiTaO 3 [20] ) as main ferroelectric materials have been widely applied to supercapacitors, [21] memories, [22] sensors, [23] and actuators, [24] which play key roles in modern technologies benefiting human lives. Nevertheless, the fatal weakness of brittleness for most perovskite oxides limits their application in flexible devices. [25] Therefore, perovskite oxide ferroelectrics are losing competitiveness in future technologies pursuing device miniaturization and flexibility. The emergence of halide perovskite ferroelectrics that feature the natural advantages of structural softness and lightweight has thus opened a new chapter in ferroelectric research.Since ferroelectricity was recognized in halide perovskites, the research activities have mainly focused on designing novel halide perovskite ferroelectrics. [35] In the past few years, the collective efforts from interdisciplinary communities have made available a collection of halide perovskite ferroelectrics with distinct compositions and structures (Figure 1c-i), such as 0D (NMP) 3 Sb 2 Cl 9 (NMP = N-methylpyrrolidinium) , [31] 1D (3-pyrrolinium)CdCl 3 , [28] 2D (BEA) 2 PbCl 4 (BEA = benzylammonium), [29] and 3D organometal (AP)RbBr 3 (AP = 3-ammoniopyrrolidinium). [30] Preliminary experiments have revealed the great promise of these materials for applications in ferroelectric photovoltaics, [36] self-powered photodetection, [37] and X-ray detection. [38] On a separate note, the development of halide perovskite ferroelectrics also raises important issues in the mechanistic investigation of halide perovskite in optoelectronics. For example, the possible existence of ferroelectricity was proposed to explain the superior optoelectronic Halide perovskites have gained tremendous attention in the past decade owing to their excellent properties in optoelectronics. Recently, a fascinating property, ferroelectricity, has been discovered in halide perovskites and quickly attracted widespread interest. Compared with traditional perovskite oxide fe...
An enantioselective Mannich‐type reaction of 3‐butynol and nitrones is described, which affords dihydrofuran‐3‐ones in good yields and with excellent enantioselectivities. The reaction is initiated by gold‐catalyzed alkyne oxidation and modification of the resulting gold carbene species with a tethered hydroxy group to form enolate species; the reaction terminates with an enantioselective Mannich‐type addition with the assistance of chiral phosphoric acid (CPA) and hydrogen bonding. This novel pattern of alkyne transformation involving chemical bond cleavage, and a fragment modification and reassembly process, provides an atom‐ and step‐economic method, and is the first example of cooperative asymmetric catalysis in gold‐catalyzed alkyne oxidations via an α‐oxo gold carbene route.
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