Covalent Modification of MoS2 with Poly(N-vinylcarbazole) for Solid-State Broadband Optical Limiters.

New soluble MoS2 nanosheets covalently functionalized with poly(N-vinylcarbazole) (MoS2-PVK) were in situ synthesized for the first time. In contrast to MoS2 and MoS2 /PVK blends, both the solution of MoS2 -PVK in DMF and MoS2-PVK/poly(methyl methacrylate) (PMMA) film show superior nonlinear optical and optical limiting responses. The MoS2-PVK/PMMA film shows the largest nonlinear coefficients (ßeff) of about 917 cm GW(-1) at λ=532 nm (cf. 100.69 cm GW(-1) for MoS2/PMMA and 125.12 cm GW(-1) for MoS2/PVK/PMMA) and about 461 cm GW(-1) at λ=1064 nm (cf. -48.92 cm GW(-1) for MoS2/PMMA and 147.56 cm GW(-1) for MoS2/PVK/PMMA). A larger optical limiting effect, with thresholds of about 0.3 GW cm(-2) at λ=532 nm and about 0.5 GW cm(-2) at λ=1064 nm, was also achieved from the MoS2-PVK/PMMA film. These values are among the highest reported for MoS2-based nonlinear optical materials. These results show that covalent functionalization of MoS2 with polymers is an effective way to improve nonlinear optical responses for efficient optical limiting devices.

Kindlin-2 Mediates Lipopolysaccharide-Induced Acute Lung Injury Partially via Pyroptosis in Mice.

Acute lung injury (ALI) is characteristic of the wholesale destruction of the lung endothelial barrier, which results in protein-rich lung edema, influx of pro-inflammatory leukocytes, and intractable hypoxemia, contributing to high mortality. Kindlin-2 is involved in the process of tumor- and wound healing-associated inflammation. However, the effects of kindlin-2 on lipopolysaccharide (LPS)-induced ALI and its mechanisms remain unknown. In this study, we found that the concentration of kindlin-2 was elevated in the lungs of ALI mice. The specific deletion of kindlin-2 by kindlin-2 siRNA attenuated the severity of lung injury, which was demonstrated by the reduced number of pro-inflammatory cells in bronchoalveolar lavage fluid and lung wet/dry weight ratio, and ameliorated pathologic changes in the lungs of ALI mice. Furthermore, kindlin-2 siRNA decreased the mRNA levels of pro-inflammatory factors (IL-1ß, IL-6, and TNF-α) and the protein levels of pyroptosis-related proteins. In vitro studies confirmed that LPS + ATP promoted the expressions of pro-inflammatory factors and pyroptosis-related proteins, which was prevented by kindlin-2 siRNA pretreatment in endothelial cells (ECs). In conclusion, inhibition of kindlin-2 developes protective effects against LPS-induced ALI and the cytotoxicity of ECs, which may depend on blocking pyroptosis.

Thermoelectric Properties of Cu2Se Nano-Thin Film by Magnetron Sputtering.

Thermoelectric technology can achieve mutual conversion between thermoelectricity and has the unique advantages of quiet operation, zero emissions and long life, all of which can help overcome the energy crisis. However, the large-scale application of thermoelectric technology is limited by its lower thermoelectric performance factor (ZT). The thermoelectric performance factor is a function of the Seebeck coefficient, electrical conductivity, thermal conductivity and absolute temperature. Since these parameters are interdependent, increasing the ZT value has always been a challenge. Here, we report the growth of Cu2Se thin films with a thickness of around 100 nm by magnetron sputtering. XRD and TEM analysis shows that the film is low-temperature α-Cu2Se, XPS analysis shows that about 10% of the film's surface is oxidized, and the ratio of copper to selenium is 2.26:1. In the range of 300-400 K, the maximum conductivity of the film is 4.55 × 105 S m-1, which is the maximum value reached by the current Cu2Se film. The corresponding Seebeck coefficient is between 15 and 30 µV K-1, and the maximum ZT value is 0.073. This work systematically studies the characterization of thin films and the measurement of thermoelectric properties and lays the foundation for further research on nano-thin-film thermoelectrics.

Doping Effect on Cu2Se Thermoelectric Performance: A Review.

Cu2Se, owing to its intrinsic excellent thermoelectric (TE) performance emerging from the peculiar nature of "liquid-like" Cu+ ions, has been regarded as one of the most promising thermoelectric materials recently. However, the commercial use is still something far from reach unless effective approaches can be applied to further increase the figure of merit (ZT) of Cu2Se, and doping has shown wide development prospect. Until now, the highest ZT value of 2.62 has been achieved in Al doped samples, which is twice as much as the original pure Cu2Se. Herein, various doping elements from all main groups and some transitional groups that have been used as dopants in enhancing the TE performance of Cu2Se are summarized, and the mechanisms of TE performance enhancement are analyzed. In addition, points of great concern for further enhancing the TE performance of doped Cu2Se are proposed.