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Chirality is essential for various amazing phenomena in life and matter. However,chirality and its switching in electronic superlattices, such as charge density wave(CDW) arrays, remain elusive. In this study, we characterize the chirality transition with atom-resolution imaging in a single-layer NbSe2 CDW pattern by technique of scanning tunneling microscopy. The atomic lattice of the CDW array is found continuous and intact although its chirality is switched. Several intermediate states are tracked by time-resolved imaging, revealing the fast and dynamic chirality transition. Importantly, the switching is reversibly realized with an external electric-field. Our findings unveil the delicate transition process of chiral CDW array in a 2D crystal down to the atomic scale and may be applicable for future nanoscale devices.

The low-energy excitations of graphene are relativistic massless Dirac fermions with opposite chiralities at valleys K and K'. Breaking the chiral symmetry could lead to gap opening in analogy to dynamical mass generation in particle physics. Here we report direct experimental evidences of chiral symmetry breaking (CSB) from both microscopic and spectroscopic measurements in a Li-intercalated graphene. The CSB is evidenced by gap opening at the Dirac point, Kekul��-O type modulation, and chirality mixing near the gap edge. Our work opens up opportunities for investigating CSB related physics in a Kekul��-ordered graphene., Kekul\'e-ordered graphene 1: Chiral symmetry breaking

Two-dimensional topological insulators (2DTI) have attracted increasing attention during the past few years. New 2DTI with increasing larger spin-orbit coupling (SOC) gaps have been predicted by theoretical calculations and some of them have been synthesized experimentally. In this review, the 2DTI, ranging from single element graphene-like materials to bi-elemental TMDs and to multi-elemental materials, with different thicknesses, structures and phases, have been summarized and discussed. The topological properties (especially the quantum spin Hall effect and Dirac fermion feature) and potential applications have been summarized. This review also points out the challenge and opportuni-ties for future 2DTI study, especially on the device applications based on the topological properties., Comment: 19 pages, 7 figures, review

Bi1−xLa x NbO4 and Bi1−xLa x NbO4 nanocomposites were prepared by a simple coprecipitation method, and their composition, structure and morphology were characterized by modern testing techniques. The antibacterial activities of the as-prepared samples against Staphylococcus aureus, Escherichia coli and Candida albicans were measured by the experiments of powder inhibition zone, inhibition zone diameter and minimum inhibitory concentration under the irradiation of sunlight. The results show that the antibacterial activities of BiNbO4 doped with La and Zn are superior to that of the parent, and the composition of antibacterial agent and their mass ratio have a great influence on the antibacterial activities. Among these, the antibacterial activity of Bi0.96La0.04NbO4 against three bacteria was best and its antibacterial activity to Candida albicans was better than those to the other two kinds.

Immunization with synthetic mRNA encoding tumor-associated antigens is an emerging vaccine strategy for the treatment of cancer. In order to prevent mRNA degradation, promote antigen-presenting cells antigen presentation, and induce an anti-tumor immune response, we investigated the nasal administration of mRNA vaccines with positively charged protamine to concentrate mRNA, form a stable polycation-mRNA complex, and encapsulate the complex with DOTAP/Chol/DSPE-PEG cationic liposomes. Cationic liposome/protamine complex (LPC) showed significantly greater efficiency in uptake of vaccine particles in vitro and stronger capacities to stimulate dendritic cell maturation, which further induced a potent anti-tumor immune response. Intranasal immunization of mice with cationic LPC containing mRNA encoding cytokeratin 19 provoked a strong cellular immune response and slowed tumor growth in an aggressive Lewis lung cancer model. The results of this study provide evidence that cationic LPC can be used as a safe and effective adjuvant and this mRNA formulation provides a basis for anti-cancer vaccination of humans.

Assessment of sustainable development of regional industry enterprises is an important content of regional sustainable development study. Based on the principles of establishing assessment index system of sustainable development of regional industrial enterprises, an index system including four-layer and 56 indicators was established, the membership function model of quantitative indexes and the choosing value standards of qualitative indexes were discussed. Based on the learning mechanism of BP neural network, the weight of each index and each layer were ultimately determined. In the end, the fuzzy comprehensive evaluation method of comprehensive assessment and a practical verifying example were given. This study can provide scientific basis for working out strategy of sustainable development of regional industrial enterprises.