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排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Kai Cheng Xiao-Shuai Zhang Jie An Cheng Li Ruo-Yun Zhang Run Ye Prof. Dr. Bang-Jiao Ye Prof. Dr. Bo Liu Prof. Dr. Yuan-Di Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(31):7553-7560
Given their superior penetration depths, photosensitizers with longer absorption wavelengths present broader application prospects in photodynamic therapy (PDT). Herein, Ag2S quantum dots were discovered, for the first time, to be capable of killing tumor cells through the photodynamic route by near-infrared light irradiation, which means relatively less excitation of the probe compared with traditional photosensitizers absorbing short wavelengths. On modification with polydopamine (PDA), PDA-Ag2S was obtained, which showed outstanding capacity for inducing reactive oxygen species (increased by 1.69 times). With the addition of PDA, Ag2S had more opportunities to react with surrounding O2, which was demonstrated by typical triplet electron spin resonance (ESR) analysis. Furthermore, the PDT effects of Ag2S and PDA-Ag2S achieved at longer wavelengths were almost identical to the effects produced at 660 nm, which was proved by studies in vitro. PDA-Ag2S showed distinctly better therapeutic effects than Ag2S in experiments in vivo, which further validated the enhanced regulatory effect of PDA. Altogether, a new photosensitizer with longer absorption wavelength was developed by using the hitherto-unexplored photodynamic function of Ag2S quantum dots, which extended and enhanced the regulatory effect originating from PDA. 相似文献
32.
Lan-Lan Zhang Dr. Wen-Ke Miao Dr. Li-Jun Ren Yu-Kun Yan Dr. Yue Lin Prof. Wei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(58):13396-13401
Organic polymers and inorganic clusters belong to two different disciplines and have completely different properties and structures. When a cluster is attached to the backbone of a polymer as a pendant, the resultant hybrid polymers (polyclusters) exhibit unique behaviours totally different from those of conventional polymers owing to the nanoscale size of the cluster and its particular interactions. Herein, the aggregation of a poly(polyoxometalate)—a polynorbornene backbone with inorganic polyoxometalate cluster pendants—upon addition of a non-solvent to its dilute solution is reported. A three-dimensional network of tangled and snake-like nanothreads was observed. Direct visualisation of individual nanoscale clusters enabled identification of single chains within the nanothreads. These observations suggest that during the process of aggregation, the hybrid polymer forms curved or extended chains as a consequence of an armouring effect in which the collapsed cluster pendants wrap around the backbone. The collapse occurs because they become less soluble in the solvent/non-solvent mixture. The extended chains then become entwined and form nanoropes consisting of multiple chains wound around each other. This study provides a deeper understanding of the nature of polyclusters and should also prove useful for their future development and application. 相似文献
33.
《Discrete Mathematics》2019,342(7):1956-1965
34.
Dr. Xiang Hao Kaixiang Yang Hairong Wang Prof. Feng Peng Prof. Haiyang Yang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(11):4344-4349
Non-Newtonian fluids are ubiquitous in daily life and industrial applications. Herein, we report an intelligent fluidic system integrating two distinct non-Newtonian rheological properties mediated by an autocatalytic enzyme reaction. Associative polyelectrolytes bearing a small amount of ionic and alkyl groups are engineered: by carefully balancing the charge density and the hydrophobic effect, the polymer solutions demonstrate a unique shear thickening property at low pH while shear thinning at high pH. The urea-urease clock reaction is utilized to program a feedback-induced pH change, leading to a strong upturn of the nonlinear viscoelastic properties. As long as the chemical fuel is supplied, two distinct non-Newtonian states can be achieved with a tunable lifetime span. As a proof of concept, we demonstrate how the physical energy-driven nonequilibrium properties can be manipulated by a chemical-fueled process. 相似文献
35.
《中国化学快报》2020,31(9):2442-2446
Nanobubble is a rising research field, which attracts more and more attentions due to its potential applications in medical science, catalysis, electrochemistry and etc. To better implement these applications, it is urgent to understand one of the most important mechanisms of nanobubbles, the evolution. However, few attentions have been paid in this aspect because of the methodology difficulties. Here we successfully used dark-field microscopy to study the evolution process of single nanobubbles generated from formic acid dehydrogenation on single Pd-Ag nanoplates. We found some of the nanobubbles in this system can exhibit three distinct states representing different sizes, which can transform among each other. These transitions are not direct but through some intermediate states. Further kinetic analysis reveals complicated mechanisms behind the evolution of single nanobubbles. The results acquired from this study can be applicable to nanobubble systems in general and provide insights into the understanding of mechanisms affecting the stability of nanobubbles and their applications. 相似文献
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39.
Yingjian Yu Dr. Bin Meng Prof. Dr. Frieder Jäkle Prof. Jun Liu Prof. Lixiang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(4):873-880
Triarylboranes that exhibit p–π* conjugation serve as versatile building blocks to design n-type organic/polymer semiconductors. A series of new molecular acceptors based on triarylborane is reported here. These molecules are designed with a boron atom that bears a bulky 2,4,6-tri-tert-butylphenyl (Mes*) substituent at the core and strong electron-withdrawing 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (IC) units as the end-capping groups that are linked to the core by bithiophene bridges. Butyl or butoxy groups are introduced to the bithiophene units to tune the optoelectronic properties. These molecules show nearly planar backbones with highly localized steric hindrance at the core, low LUMO/HOMO energy levels, and broad absorption bands spanning the visible region, which are all very desirable characteristics for use as electron acceptors in organic solar cell (OSC) applications. The attachment of butyl groups to the bithiophene bridges brings about a slightly twisted backbone, which in turn promotes good solubility and homogeneous donor/acceptor blend morphology, whereas the introduction of butoxy groups leads to improved planarity, favorable stacking in the film state, and a greatly reduced band gap. OSC devices based on these molecules exhibit encouraging photovoltaic performances with power conversion efficiencies reaching up to 4.07 %. These results further substantiate the strong potential of triarylboranes as the core unit of small molecule acceptors for OSC applications. 相似文献
40.
Hongxing Jia Prof. Guilin Zhuang Qiang Huang Jinyi Wang Yayu Wu Shengsheng Cui Prof. Shangfeng Yang Prof. Pingwu Du 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(10):2159-2163
Bottom-up synthesis of π-extended macrocyclic carbon rings is promising for constructing length- and diameter-specific carbon nanotubes (CNTs). However, it is still a great challenge to realize size-controllable giant carbon macrocycles. Herein, a tunable synthesis of curved nanographene-based giant π-extended macrocyclic rings (CHBC[n]s; n=8, 6, 4), as finite models of armchair CNTs, is reported. Among them, CHBC[8] contains 336 all-carbon atoms and is the largest cyclic conjugated molecular CNT segment ever reported. CHBC[n]s were systematically characterized by various spectroscopic methods and applied in photoelectrochemical cells for the first time. This revealed that the proton chemical shifts, fluorescence, and electronic and photoelectrical properties of CHBC[n]s are highly dependent on the macrocycle diameter. The tunable bottom-up synthesis of giant macrocyclic rings could pave the way towards large π-extended diameter- and chirality-specific CNT segments. 相似文献