Berry phase in quantum oscillations of topological materials

Quantum oscillation is an important phenomenon in low temperature transport studies of topological materials. In three-dimensional topological insulators, Dirac semimetals, Weyl semimetals, and other topological nontrivial materials, the topologically nontrivial band structure will add a phase correction to the quantum oscillation patterns, which is known as the nontrivial Berry phase. Berry phase analysis via quantum oscillation is a powerful method to investigate the nontrivial band topology of topological materials. In this review, we introduce the concepts of the Berry phase and quantum oscillations, and provide some classification of topological materials. We then employ some important studies on each type of topological material to discuss the nontrivial Berry phase. We conclude by pointing out the importance of quantum transport studies on topological materials, as well as drawing attention to the exploration of the nontrivial Berry phase in a new material system that could shed more light on the topology-based electronics

Ionogels of Sugar Surfactant in Ethylammonium Nitrate: Phase Transition from Closely Packed Bilayers to Right-Handed Twisted Ribbons

In the simplest ionic liquid, ethylammonium nitrate (EAN), ionogels with high mechanical strength were prepared from a surfactant with a disaccharide polar head. Phase structures from closely packed bilayers to right-handed twisted ribbons were determined via freeze-fracture transmission electron microscopy (FF-TEM) observations. The phase transition mechanism was investigated deeply and systematically. The temperature contributes to suitable tail chain conformations of surfactant molecules for adapting to different self-assembled structures including right-handed twisted ribbons and bilayers. Two different arrays were revealed for different bilayers by the small-angle X-ray scattering (SAXS) measurements. The rheological and tribological properties of the ionogels were investigated. The better lubricating property and antiwear capability of the ionogels compared to the EAN may be attributed to the structure characteristics and the good thixotropic properties

Spin Gapless Quantum Materials and Devices

Quantum materials, with nontrivial quantum phenomena and mechanisms, promise efficient quantum technologies with enhanced functionalities. Quantum technology is held back because a gap between fundamental science and its implementation is not fully understood yet. In order to capitalize the quantum advantage, a new perspective is required to figure out and close this gap. In this review, spin gapless quantum materials, featured by fully spin-polarized bands and the electron/hole transport, are discussed from the perspective of fundamental understanding and device applications. Spin gapless quantum materials can be simulated by minimal two-band models and could help to understand band structure engineering in various topological quantum materials discovered so far. It is explicitly highlighted that various types of spin gapless band dispersion are fundamental ingredients to understand quantum anomalous Hall effect. Based on conventional transport in the bulk and topological transport on the boundaries, various spintronic device aspects of spin gapless quantum materials as well as their advantages in different models for topological field effect transistors are reviewed

Photoinduced Self-Structured Surface Pattern on a Molecular Azo Glass Film: Structure–Property Relationship and Wavelength Correlation

In this study, three series of star-shaped molecular azo glasses were synthesized, and self-structured surface pattern formation on the azo compound films was studied by laser irradiation at different wavelengths. The molecular azo glasses were synthesized from three core precursors (Tr-AN, Tr-35AN, Tr-H35AN), which were prepared by ring-opening reactions between 1,3,5-triglycidyl isocyanurate and corresponding aniline derivatives. The star-shaped azo compounds were obtained through azo-coupling reactions between the core precursors and diazonium salts of 4-chloroaniline, 4-aminobenzonitrile, and 4-nitroaniline, respectively. By using the two-step reaction scheme, three series of azo compounds with different structures were obtained. The core precursors and azo compounds were characterized by using 1H NMR, FT-IR, UV–vis, mass spectrometry, and thermal analyses. The self-structured surface pattern formation on films of the azo compounds was studied by irradiating the azo compound films with a normal-incident laser beam at different wavelengths (488, 532, and 589 nm). The results show that the photoinduced surface pattern formation behavior is closely related to the structure of the azo compounds, excitation wavelength, and light polarization conditions. The absorption band position of the π–π* transition is mainly determined by the electron-withdrawing groups on the azo chromophores. When the excitation wavelength is between λmax and the band tail at the longer wavelength side, the self-structured surface patterns can be more efficiently induced to form on the films. The 3,5-dimethyl substitution on azo chromophores inhibits the surface pattern formation for certain excitation wavelengths. Increasing molecular interaction also shows an effect of restraining the surface pattern formation. The irradiations with linearly and circularly polarized light cause significant differences in the alignment manner of the pillarlike structures and their saturated height

DataSheet1_Prognosis and immune infiltration analysis of endoplasmic reticulum stress-related genes in bladder urothelial carcinoma.xlsx

Background: Abnormal activation of endoplasmic reticulum (ER) stress sensors and their downstream signalling pathways is a key regulator of tumour growth, tumour metastasis and the response to chemotherapy, targeted therapy and immunotherapy. However, the study of ER stress on the immune microenvironment of bladder urothelial carcinoma (BLCA) is still insufficient.Methods: Firstly, 23 ER stress genes were selected to analyse their expression differences and prognostic value in BLCA based on the existing BLCA genome atlas data. According to the expression level of ER stress-related genes in BLCA, two independent clusters were identified using consensus cluster analysis. Subsequently, the correlation between these two clusters in terms of the immune microenvironment and their prognostic value was analysed. Finally, we analysed the prognostic value of the key ER stress gene HSP90B1 in BLCA and its corresponding mechanism that affects the immune microenvironment.Results: Consensus clustering showed a worse prognosis and higher expression of immunoassay site-related genes (HAVCR2, PDCD1, CTLA4, CD274, LAG3, TIGIT and PDCD1LG2) in cluster 1 compared with cluster 2. Additionally, both TIMER and CIBERSORT algorithms showed that the expression of immune infiltrating cells in cluster 1 was significantly higher than that in cluster 2. Subsequently, HSP90B1 was identified as a key ER stress gene in BLCA, and its high expression indicated poor prognosis and was closely related to PD1. We also analysed the correlation between HSP90B1 expression and immune-infiltrating cell related biomarkers, which showed positive results. Finally, we verified the prognostic value of HSP90B1 in BLCA using an immunohistochemical assay in a tissue microarray of 100 patients with BLCA, validating the potential of HSP90B1 as a prognostic biomarker in patients with BLCA.Conclusion: Our work reveals that ER stress genes play a crucial role in the BLCA immunological milieu, and HSP90B1 is a potential prognostic biomarker and therapeutic target for cancer immunotherapy.</p

DataSheet2_Prognosis and immune infiltration analysis of endoplasmic reticulum stress-related genes in bladder urothelial carcinoma.docx

Background: Abnormal activation of endoplasmic reticulum (ER) stress sensors and their downstream signalling pathways is a key regulator of tumour growth, tumour metastasis and the response to chemotherapy, targeted therapy and immunotherapy. However, the study of ER stress on the immune microenvironment of bladder urothelial carcinoma (BLCA) is still insufficient.Methods: Firstly, 23 ER stress genes were selected to analyse their expression differences and prognostic value in BLCA based on the existing BLCA genome atlas data. According to the expression level of ER stress-related genes in BLCA, two independent clusters were identified using consensus cluster analysis. Subsequently, the correlation between these two clusters in terms of the immune microenvironment and their prognostic value was analysed. Finally, we analysed the prognostic value of the key ER stress gene HSP90B1 in BLCA and its corresponding mechanism that affects the immune microenvironment.Results: Consensus clustering showed a worse prognosis and higher expression of immunoassay site-related genes (HAVCR2, PDCD1, CTLA4, CD274, LAG3, TIGIT and PDCD1LG2) in cluster 1 compared with cluster 2. Additionally, both TIMER and CIBERSORT algorithms showed that the expression of immune infiltrating cells in cluster 1 was significantly higher than that in cluster 2. Subsequently, HSP90B1 was identified as a key ER stress gene in BLCA, and its high expression indicated poor prognosis and was closely related to PD1. We also analysed the correlation between HSP90B1 expression and immune-infiltrating cell related biomarkers, which showed positive results. Finally, we verified the prognostic value of HSP90B1 in BLCA using an immunohistochemical assay in a tissue microarray of 100 patients with BLCA, validating the potential of HSP90B1 as a prognostic biomarker in patients with BLCA.Conclusion: Our work reveals that ER stress genes play a crucial role in the BLCA immunological milieu, and HSP90B1 is a potential prognostic biomarker and therapeutic target for cancer immunotherapy.</p

Self-Structured Surface Patterns on Epoxy-Based Azo Polymer Films Induced by Laser Light Irradiation

In this study, two series of epoxy-based azo polymers with high chromophore density were synthesized and self-structured surface pattern formation on the polymer films was studied by laser light irradiation under different conditions. To synthesize the azo polymers, two epoxy-based precursor polymers (PEP-AN and PEP-35AN) were prepared by step polymerizations of N,N-di(epoxypropyl)aniline and N,N-di(epoxypropyl)-3,5-dimethylaniline with aniline and 3,5-dimethylaniline, respectively. The azo polymers were obtained through postpolymerization azo-coupling reactions between the precursor polymers and diazonium salts of 4-chloroaniline, 4-aminobenzonitrile, 4-nitroaniline, and 2-methyl-4-nitroaniline. The epoxy-based precursor polymers and azo polymers were characterized by using 1H NMR, FT-IR, UV–vis, and DSC analyses. The self-structured surface pattern formation on films of the two series of azo polymers was studied by irradiating the polymer films with a normal-incident laser beam at two different wavelengths (488 and 532 nm). The results show that the photoinduced surface pattern formation is closely related with the structure of azo chormophores, excitation wavelength, and light polarization condition. The efficient excitation wavelength is closely related with the absorption band position, which is mainly determined by the electron-withdrawing groups on the azo chromophores. The methyl substituents on the azo chromophores can enhance the photoinduced surface pattern formation ability in some cases. For comparison, the surface-relief-grating (SRG) formation was studied by irradiating the polymer films with interfering laser light. The SRG formation rate is also dependent on the azo chromophore structure and wavelength of the incident laser light. The self-structured surface pattern formation needs a higher energy input and shows stricter wavelength requirement compared with those of the SRG formation. These observations could lead to the deeper understanding of the mechanism of the self-structured surface pattern formation and development of materials with better performance

Topological insulator materials for advanced optoelectronic devices

Topological insulators are quantum materials that have an insulating bulk state and a topologically protected metallic surface state with spin and momentum helical locking and a Dirac-like band structure. Unique and fascinating electronic properties, such as the quantum spin Hall effect, quantum anomalous Hall effect, and topological magnetoelectric effect, as well as magnetic monopole images and Majorana fermions, have been observed in the topological insulator materials. With these unique properties, topological insulator materials have great potential applications in spintronics and quantum information processing, as well as magnetoelectric devices with higher efficiency and lower energy consumption. On the other hand, topological insulator materials also exhibit a number of excellent optical properties, including Kerr and Faraday rotation, ultrahigh bulk refractive index, near-infrared frequency transparency, unusual electromagnetic scattering, and ultra-broadband surface plasmon resonances. Specifically, Dirac plasmon excitations have been observed in Bi2Se3 micro-ribbon arrays at THz frequencies. Ultraviolet and visible frequency plasmonics have been observed in nanoslit and nanocone arrays of Bi1.5Sb0.5Te1.8Se1.2 crystals. High transparency has been observed in Bi2Se3 nanoplates. An ultrahigh refractive index has been observed in bulk Bi1.5Sb0.5Te1.8Se1.2 crystals as well as in Sb2Te3 thin films. These excellent optical properties mean that topological insulator materials are suitable for various optoelectronic devices, including plasmonic solar cells, ultrathin holograms, plasmonic and Fresnel lens, broadband photodetectors, and nanoscale waveguides. In this chapter, we focus on the excellent electronic and optical properties of topological insulator materials and their wide applications in advanced optoelectronic devices

Local and Sustained Gene Delivery in Silica-Collagen Nanocomposites

Local delivery of biomolecules from hydrogels is highly challenging because of their rapid diffusion and degradation. Gene therapy represents an alternative that allows for the prolonged production of proteins by transfected cells. In this study, we have developed nanocomposites consisting of DNA-polyethylenimine-silica nanoparticle complexes coencapsulated with fibroblasts within collagen hydrogels. Through the modulation of the particle size and polyethylenimine molecular weight, it was possible to achieve “in-gel” transfection permitting the sustained production of biomolecules from hydrogels over 1 week. Alternative configurations consisting of particle addition to cellularized gels and cell culture in the presence of complex-containing hydrogels were also investigated. These studies demonstrated that particle encapsulation limits DNA and silica dissemination outside the collagen hydrogels. They also show the key role of cell proliferation within collagen hydrogels on the transfection efficiency. Such nanocomposites therefore constitute promising materials for the development of novel gene delivery systems to promote tissue repair