Performance Enhancement of Tin-Based Perovskite Photodetectors through Bifunctional Cesium Fluoride Engineering.

Tin halide perovskites are rising as promising candidates for next-generation optoelectronic materials due to their good optoelectronic properties and relatively low toxicity. However, the high defect density and the easy oxidation of Sn2+ have limited their optoelectronic performance. Herein, we report the treatment of the FASnI3 (formamidinium tin, FA) perovskite film by a bifunctional cesium fluoride (CsF) additive, which improves the film quality and significantly enhances the photoelectric performance. The responsivity of the perovskite-based photodetector (PD) with an optimal CsF concentration of 15% is over 60 times larger than that of the PD without CsF. It indicates that both the Cs substitution and the fluoride anion additive from CsF inhibit the oxidation of Sn2+, optimize the crystal growth, and passivate the defects, demonstrating the dual roles of the CsF additive in improving the photoelectric performance. This work offers valuable insights into the additive selection for developing high-quality tin-based perovskite films and devices.

Cardioprotection of mAb2G4/ODN/lip on Myocardial Ischemia-Reperfusion Injury via Inhibiting the NF-κB Signaling Pathway.

Substantial evidence suggests that the interventions of NF-κB would likely effectively prevent inflammatory response and reduce myocardial damage in the ischemic myocardium. And the NF-кB decoy ODN is a specific inhibitor that suppresses the expression of NF-κB. Herein, we revealed the effect and possible mechanism of mAb2G4/ODN/lip on myocardial ischemia-reperfusion injury (MI/RI). As shown in the results, post-treatment with mAb2G4/ODN/lip improved the impaired histological morphology in the MI/RI model and elevated cell viability in the H/R model. The mAb2G4/ODN/lip complex inhibited the NLRP3 signaling pathway and decreased the expression of LDH, IL-1ß, TNF-α, IL-6, and MDA. Mechanistically, we demonstrated that post-treatment with mAb2G4/ODN/lip exerted protective effects against I/R injuries by inhibiting the NF-кB-related inflammatory response. In summary, the present study may offer a novel therapeutic strategy for treating MI/RI.

Significant Interfacial Dielectric Relaxation of Covalently Bonded Ice-Hydrogels.

Hydrogels are composed of a three-dimensional network of cross-linked hydrophilic polymer chains and large amounts of water. The physicochemical properties of the polymer-water interface in hydrogels draw our attention. Due to the complex structure of hydrogel systems, it is still a challenge to investigate the interfacial layer properties of hydrogels through experiments. In this work, we investigate the properties of the covalently bonded chitosan-based ice-hydrogels interfacial layer by dielectric relaxation spectroscopy (DRS) techniques in the presence of avoided electrode polarization. The DRS data exhibit that the polymer-water interfacial layer has a strong dielectric signal response, which indicates that a large number of polar electric dipoles or polar molecules may be contained in the interfacial layer. The variable temperature dielectric relaxation behavior of a series of chitosan-base ice-hydrogels showed that the value of dielectric activation energy for different water contents is about 180 kJ/mol, which is much larger than that of the polymer and ice phases, suggesting a strong coupling of polar electric dipoles within the interfacial layer. This work demonstrates the important role of the polymer-water interface in covalently bonded hydrogels, which will provide assistance in the design and application of covalently bonded hydrogels.

Propofol inhibits biological functions of leukaemia stem and differentiated cells through suppressing Wnt/ß-catenin and Akt/mTOR.

The biological roles of intravenous anaesthetic propofol in cancer have been shown by various studies using cancer cell lines that represent differentiated cancer cells. However, the activities of propofol in cancer stem cells have not been elucidated. In this work, we examined the effects and mechanisms of propofol on acute myeloid leukaemia (AML) differentiated and CD34+ CD38- stem cells. We found that propofol inhibited growth, differentiation and self-renewal capabilities of AML stem cells regardless of cellular origin and genetic profiling. In addition, propofol inhibited the growth of AML differentiated cells. Propofol significantly induced apoptosis of AML differentiated but not CD34+ CD38- stem cells. We further found that propofol significantly augmented the efficacy of AML standard therapeutic drugs. Consistent with the previous findings, we showed that propofol suppressed the Akt/mTOR pathway in AML cells. We also found that propofol inhibited pathways important for stem cell maintenance and self-renewal, such as Wnt/ß-catenin. Overexpression of constitutively active Akt partially reversed the inhibitory effects of propofol in AML differentiated cells. Stabilization of ß-catenin using genetic and pharmacological approaches also partially rescued the inhibitory effects of propofol in AML differentiated and stem cells. Our work shows that propofol targets leukaemia cells at all stages of development, in a cell type-specific manner. Inhibition of both Akt/mTOR and Wnt/ß-catenin is required for the action of propofol in AML. Our findings also highlight the activities of propofol on cancer stem cells.

Giant photostriction in organic-inorganic lead halide perovskites.

Among the many materials investigated for next-generation photovoltaic cells, organic-inorganic lead halide perovskites have demonstrated great potential thanks to their high power conversion efficiency and solution processability. Within a short period of about 5 years, the efficiency of solar cells based on these materials has increased dramatically from 3.8 to over 20%. Despite the tremendous progress in device performance, much less is known about the underlying photophysics involving charge-orbital-lattice interactions and the role of the organic molecules in this hybrid material remains poorly understood. Here, we report a giant photostrictive response, that is, light-induced lattice change, of >1,200 p.p.m. in methylammonium lead iodide, which could be the key to understand its superior optical properties. The strong photon-lattice coupling also opens up the possibility of employing these materials in wireless opto-mechanical devices.

Electrical and mechanical switching of ferroelectric polarization in the 70 nm BiFeO3 film.

Ferroelectric polarization switching and its domain evolution play a key role on the macroscopic electric properties of ferroelectric or piezoelectric devices. Mechanical switching has been reported recently in ~5 nm BaTiO3 and PbZr0.2Ti0.8O3 epitaxial films; however it is still a challenge for a mechanical force to switch polarization of a slightly thicker film in the same way as an electric field. Here, we report that the polarization of a 70 nm BiFeO3 epitaxial film can be completely switched by a mechanical force, and its domain evolution is similar to that observed with electrical switching. With the gradual increase of the field/force, new domains nucleate preferentially at domain boundaries, the µm-size domains commonly decompose to a mass of nm-size domains, and finally they may reorganize to µm-size domains which undergo 180(°) polarization switching through multi steps. Importantly, the complete mechanical switching of polarization was also established in the (0 0 1) film with a smooth surface. Furthermore, either upward or downward polarization can be read out nondestructively by a constant current. Our study sheds light on prospective applications of ferroelectrics in the absence of an electric field, such as memory devices and other micro-electromechanical systems.

The effect of butorphanol postconditioning on myocardial ischaemia reperfusion injury in rats.

OBJECTIVES: Butorphanol tartrate is a synthetic opioid partial agonist analgesic. Butorphanol targets the heart, mainly via κ-opioid receptor (κ-OR) activation. The purpose of this study was to determine the effect and mechanism underlying butorphanol postconditioning (B-Post) on myocardial ischaemia reperfusion injury in rats. METHODS: Seventy-five male Sprague-Dawley rats were randomly divided into five groups of 15 each: Group sham; Group I/R (ischaemia/reperfusion); Group B (butorphanol postconditioning); Group B/N (butorphanol postconditioning + antagonist of κ-OR nor-binaltorphimine [Nor-BNI]); Group B/G (butorphanol postconditioning + nonselective ATP-sensitive potassium (KATP) channel blocker glibenclamide [GLI]). The left coronary anterior descending artery (LAD) was occluded for 30 min, followed by a 120-min reperfusion. Blood samples were obtained at the end of reperfusion for determination of serum tumour necrosis factor (TNF)-α and interleukin (IL)-6 concentrations. The hearts were then excised for determination of myocardial infarct size by triphenyltetrazolium chloride staining. The myocardial tissues were used for determination of the expression of myocardial superoxide dismutase (SOD), malondialdehyde (MDA) and myeloperoxidase (MPO). RESULTS: Myocardial infarct size was significantly reduced in B (26.4 ± 1.83%), B/N (34.5 ± 1.56%) and B/G (31.5 ± 1.27%) Groups compared with Group I/R (46.8 ± 1.41%) (all P < 0. 001). The serum TNF-α and IL-6 concentrations and the MDA and MPO activities in the ischaemic area in B, B/N and B/G Groups were significantly lower than those in the I/R Group (all P < 0.001). In addition, myocardial infarct size, TNF-α and IL-6 concentrations and the MDA and MPO activities in B/N and B/G Groups were higher than those in the B Group (all P < 0.001). In contrast, SOD activity was significantly increased in B, B/N and B/G Groups, and SOD activity in B/N and B/G Groups was less than in the B Group (all P < 0.001). CONCLUSIONS: These results suggest that postconditioning of butorphanol tartrate can provide a potent cardioprotective effect against myocardial ischaemic and reperfusion injury. Both the κ-OR and the KATP channels were involved in this effect.