20 research outputs found
Multifunctional Lateral Transition-Metal Disulfides Heterojunctions
The intrinsic spin-dependent transport properties of two types of lateral
VS2|MoS2 heterojunctions are systematically investigated using first-principles
calculations, and their various nanodevices with novel properties are designed.
The lateral VS2|MoS2 heterojunction diodes show a perfect rectifying effect and
are promising for the applications of Schottky diodes. A large
spin-polarization ratio is observed for the A-type device and pure
spin-mediated current is then realized. The gate voltage significantly tunes
the current and rectification ratio of their field-effect transistors (FETs).
In addition, they all have sensitive photoresponse to blue light, and could be
used as photodetector and photovoltaic device. Moreover, they generate the
effective thermally-driven current when a temperature gratitude appears between
the two terminals, suggesting them as potential thermoelectric materials.
Hence, the lateral VS2|MoS2 heterojunctions show a multifunctional nature and
have various potential applications in spintronics, optoelectronics, and spin
caloritronics
Origin of Improved Photoelectrochemical Water Splitting in Mixed Perovskite Oxides
Owing to the versatility in their chemical and physical properties,
transition metal perovskite oxides have emerged as a new category of highly
efficient photocatalysts for photoelectrochemical water splitting. Here, to
understand the underlying mechanism for the enhanced photoelectrochemical water
splitting in mixed perovskites, we explore ideal epitaxial thin films of the
BiFeO3-SrTiO3 system. The electronic struture and carrier dynamics are
determined from both experiment and density-functional theory calculations. The
intrinsic phenomena are measured in this ideal sytem, contrasting to commonly
studied polycrstalline solid solutions where extrinsic structural features
obscure the intrinsic phenomena. We determined that when SrTiO3 is added to
BiFeO3 the conduction band minimum position is raised and an exponential tail
of trap states from hybridized Ti 3d and Fe 3d orbitals emerges near the
conduction band edge. The presence of these trap states strongly suppresses the
fast electron-hole recombination and improves the photocurrent density in the
visible-light region, up to 16 times at 0 VRHE compared to the pure end member
compositions. Our work provides a new design approach for optimising the
photoelectrochemical performance in mixed perovksite oxides.Comment: 7 pages and 5 figure
Protective Role of Nuclear Factor-Erythroid 2-Related Factor 2 Against Radiation-Induced Lung Injury and Inflammation
Radiation-induced lung injury (RILI) is one of the most common and fatal complications of thoracic radiotherapy. Inflammatory cell infiltration, imbalance of inflammatory cytokines, and oxidative damage were reported to be involved during RILI pathogenesis, especially in the early phase of RILI. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a key transcriptional regulator of antioxidative cascades, and regulates life span of mice after administration of thoracic irradiation. We investigated the effects of Nrf2 on RILI and inflammation using Nrf2-knockout, Nrf2-overexpression and wild-type mice with or without 15 Gy ionizing radiation to thorax. Our results showed that Nrf2 deficiency aggravated radiation-induced histopathological changes, macrophage and neutrophil infiltration, serum levels of pro-inflammatory cytokines (IL-6, MCP-1, IFN-γ, TNF, and IL-12p70), and the levels of peroxidation products in the mouse lung. Moreover, loss of Nrf2 reduced radiation-induced serum levels of anti-inflammatory cytokine, IL-10, and antioxidative proteins. Nrf2 overexpression significantly alleviated radiation-induced histopathological changes, macrophages and neutrophils infiltration, serum levels of pro-inflammatory cytokines, and the levels of peroxidation products in lung tissues. Nrf2 overexpression also increased the serum levels of IL-10 and antioxidative proteins. These results indicated that Nrf2 had a protective role against radiation-induced acute lung injury and inflammation, and that antioxidative therapy might be a promising treatment for RILI
Extensive Sampling Provides New Insights into Phylogenetic Relationships between Wild and Domesticated <i>Zanthoxylum</i> Species in China
Zanthoxylum, belonging to the Rutaceae family, is widely distributed in tropical and subtropical regions. The genus has high economic value as spices, oils, medicinal plants, and culinary applications. Zanthoxylum has a long history of domestication and cultivation in China. However, the phylogenetic relationships and origin of wild and cultivated Zanthoxylum species in China remain largely unknown. Moreover, there is still no clear molecular phylogenetic system for Zanthoxylum species. Herein, 373 Zanthoxylum samples were collected from all presently known provenances of Zanthoxylum in China. In this study, four chloroplast DNA (cpDNA) markers (matK, ndhH, psbB, rbcL) were used to comprehensively analyze the genetic diversity, relatedness, and geographical origin of Chinese Zanthoxylum species. The results were as follows: (1) The aligned length of the four pairs of cpDNA sequences was 3836 bp, and 68 haplotypes were identified according to 219 variable polymorphic sites, including 90 singleton variable sites, 129 parsimony informative sites, 3 Indels (insertions and deletions). (2) Phylogenetic tree and haplotype network strongly supported the division of Zanthoxylum species consistent with the taxonomic recognition of five species: Z. bungeanum, Z. piasezkii, Z. piperitum, Z. armatum, and Z. micranthum. (3) Divergence time estimation suggested that Zanthoxylum genus originated from the Late Eocene, and most Zanthoxylum species diverged after the Middle Miocene. (4) Haplotype 16 (H16) was at the bottom of the phylogenetic tree, had higher haplotype diversity (Hd) and nucleotide polymorphism (Pi) than other haplotypes, and was located in the center of the network figure. Therefore, we deduced that the cultivated Zanthoxylum species may originate in Zhouqu County, Gansu Province, China. Meanwhile, our research provided a scientific basis for the identification and breeding programs of Chinese Zanthoxylum species