A series of new organic semiconductors based on s‐indaceno[1,2‐b:5,6‐b′]dithiophene‐4,9‐dione was successfully synthesized and characterized. The electron withdrawing carbonyl group lowers the LUMO energy levels, leading to increased electronegativities, which is beneficial for high photo‐stability in air. The n‐alkyl substituted compounds, 1c and 1d , crystallize with the rigid coplanar systems packed into slipped face‐to‐face π‐stacks. Interestingly, 1c and 1d also show liquid crystalline behaviors, which give highly ordered molecular packing over large area. 相似文献
A subset ${S \subseteq V(G)}$ is a double dominating set of G if S dominates every vertex of G at least twice. The double domination numberdd(G) is the minimum cardinality of a double dominating set of G. The double domination subdivision number sddd(G) is the minimum number of edges that must be subdivided (where each edge in G can be subdivided at most once) in order to increase the double domination number. Atapour et al. (Discret Appl Math, 155:1700–1707, 2007) posed an open problem: Prove or disprove: let G be a connected graph with no isolated vertices, then 1 ≤ sddd(G) ≤ 2. In this paper, we disprove the problem by constructing some connected graphs with no isolated vertices and double domination subdivision number three. 相似文献
Photodynamic therapy (PDT) plays an important role in tumor therapy. However, PDT outcomes remain poor due to the insufficient reactive oxygen species (ROS) yield of the photosensitizer and the aggravation of hypoxia in the tumor microenvironment through PDT. To solve this issue, a puissant PDT nanoparticles (NPs) platform is developed to defeat tumors by employing powerful PDT in an oxygen-enriched tumor microenvironment and by inhibiting tumor migration through regulating hypoxia-related pathways. Specifically, TFM, as a previously reported AIEgen, does not emit brightly but instead makes use of its nonradiative relaxation for ROS generation, along with oxygen regulator doxycycline (DOXY), both of which are encapsulated in NPs that can specifically penetrate deep into tumor tissue. After released from the NPs, TFM functions as a powerful ROS generator, and DOXY reduces endogenous oxygen consumption via regulating mitochondrial cytochrome oxidase 1, further enhancing TFM-mediated PDT efficacy. Meanwhile, reoxygenation is observed to reduce the expression of hypoxia inducible factor-1α and M2 macrophages induced by PDT. The amplified PDT not only strongly killed tumor but, along with the downregulated hypoxia related pathways during the post-PDT process, inhibited tumor migration. In summary, such NPs exhibit potent anti-tumor effects for advanced bladder cancer therapy. 相似文献
Clay adsorbents are considered an inexpensive and readily available solution for removing heavy metals, including cadmium, from the environment to reduce pollution. In this study, thiol-modified bentonite (SH-Bent) was prepared by grafting cysteamine hydrochloride onto natural bentonite (Bent). The effects of pH, equilibrium contact time, and temperature on the adsorption–desorption behavior of Cd2+ were studied, and adsorption isotherm models were applied to examine the adsorption behavior of SH-bent. SH-Bent demonstrated better performance and stability for Cd2+ adsorption than Bent. SH-Bent exhibited an enhanced adsorption capacity for Cd2+ at equilibrium of 49.3 mg/g at pH 6, 120 min, and 303 K, which was 42-fold higher than that of Bent under the same conditions. An investigation of the desorption behavior of Cd2+ adsorbed on Bent and SH-Bent in simulated acid rain revealed that SH-Bent has high stability, with a desorption rate of 5.73% at pH 4.5, 60 min, and 303 K, which was much lower than that demonstrated by Bent under the same conditions (45.68%). The Langmuir equation was the best-fitted adsorption isotherm model, closely followed by the Freundlich, Tempkin, and Dubinin–Radushkevich models. A significant difference in diffusion was observed between the two types of clay according to the intraparticle diffusion model. The adsorption–desorption processes of SH-Bent and Bent fit the pseudo-second-order model best among the five kinetic models examined. The information provided in this study can be used to apply thiol-modified clay for wastewater treatment or for the removal of cadmium from soil.