Gate-Tunable Tunneling Resistance in Graphene/Topological Insulator Vertical Junctions

Graphene-based vertical heterostructures, particularly stacks incorporated with other layered materials, are promising for nanoelectronics. The stacking of two model Dirac materials, graphene and topological insulator, can considerably enlarge the family of van der Waals heterostructures. Despite well understanding of the two individual materials, the electron transport properties of a combined vertical heterojunction are still unknown. Here we show the experimental realization of a vertical heterojunction between Bi2Se3 nanoplate and monolayer graphene. At low temperatures, the electron transport through the vertical heterojunction is dominated by the tunneling process, which can be effectively tuned by gate voltage to alter the density of states near the Fermi surface. In the presence of a magnetic field, quantum oscillations are observed due to the quantized Landau levels in both graphene and the two-dimensional surface states of Bi2Se3. Furthermore, we observe an exotic gate-tunable tunneling resistance under high magnetic field, which displays resistance maxima when the underlying graphene becomes a quantum Hall insulator

Evidence of Public Service Motivation and Job Satisfaction of Public Sector Employees in China

The main purpose of this paper is to investigate how generalizable the public service motivation (PSM) is to China and examine the instrumentality through which individual PSM may affect work attitudes in an administrative or public organization. Using the data from the questionnaire among the Provincial Governments in China, the structure of PSM and the effects of PSM on job satisfaction (JS) is explored. The survey is coverage of provincial government departments’ employees in China, and a total of 1027 effective samples were collected. A variety of research methods are used, such as descriptive statistics analysis, exploratory factor analysis, correlation analysis, and regression analysis and so on. These studies not only explore and examine the constitution and adaptability of PSM, but also produce interesting results that relate to the history and institutional background of Chinese administrative or public organizations

A Novel Chemosynthetic Peptide with β-Sheet Motif Efficiently Kills Klebsiella pnuemoniae in a Mouse Model

Klebsiella pneumoniae (Kp) is one of the most common pathogens in nosocomial infections and is increasingly becoming multiple drug resistant. However, the molecular pathogenesis of Kp in causing tissue injury and dysregulated host defense remains elusive, further dampening the development of novel therapeutic measures. We have previously screened a series of synthetic antimicrobial beta-sheet forming peptides and identified a peptide (IRIKIRIK; ie, IK8L) with a broad range of bactericidal activity and low cytotoxicity in vitro. Here, employing an animal model, we investigated the antibacterial effects of IK8L in acute infection and demonstrated that peritoneal injection of IK8L to mice down-regulated inflammatory cytokines, alleviated lung injury, and importantly, decreased mortality compared to sham-injected controls. In addition, a math model was used to evaluate in vivo imaging data and predict infection progression in infected live animals. Mechanistically, IK8L can kill Kp by inhibiting biofilm formation and modulating production of inflammatory cytokines through the STAT3/JAK signaling both in vitro and in vivo. Collectively, these findings reveal that IK8L may have potential for preventing or treating Kp infection

X-Ray Repair Cross Complementing 4 (XRCC4) Genetic Single Nucleotide Polymorphisms and the Liver Toxicity of AFB1 in Hepatocellular Carcinoma

Our previous reports have shown that the genetic single-nucleotide polymorphisms (GSNPs) in the DNA repair gene X-ray repair cross complementing 4 (XRCC4) are involved in the carcinogenesis of hepatocellular carcinoma (HCC) induced by aflatoxin B1 (AFB1). However, the effects of GSNPs in the coding regions of XRCC4 on hepatic toxicity of AFB1 have been less investigated. We conducted a hospital-based clinic tissue samples with pathologically diagnosed HCC (n = 380) in a high AFB1 exposure area to explore the possible roles of GSNPs in the coding regions of XRCC4 in AFB1-induced HCC using liver toxicity assays. A total of 143 GSNPs were included in the present study and genotyped using the SNaPshot method, whereas the liver toxicity of AFB1 was evaluated using AFB1-DNA adducts in the tissues with HCC. In the clinicopathological samples with HCC, the average adduct amount is 2.27 ± 1.09 μmol/mol DNA. Among 143 GSNPs of XRCC4, only rs1237462915, rs28383151, rs762419679, rs766287987, and rs3734091 significantly increased the levels of AFB1-DNA adducts. Furthermore, XRCC4 GSNPs (including rs28383151, rs766287987, and rs3734091) also increased cumulative hazard for patients with HCC. These results suggest that the liver toxicity of AFB1 may be modified by XRCC4 GSNPs

Developmental expression of survivin during embryonic submandibular salivary gland development

BACKGROUND: The regulation of programmed cell death is critical to developmental homeostasis and normal morphogenesis of embryonic tissues. Survivin, a member of the inhibitors of apoptosis protein (IAP) family primarily expressed in embryonic cells, is both an anti-apoptosis and a pro-survival factor. Since our previous studies have demonstrated the importance of apoptosis during embryonic submandibular salivary gland (SMG) development, we postulated that survivin is a likely mediator of SMG epithelial cell survival. RESULTS: We investigated the developmental expression of survivin in Pseudoglandular (~ E14), Canalicular (~ E15) and Terminal Bud (~ E17) Stage SMGs. We report a significant 26% increase in transcript levels between the Canalicular and Terminal Bud Stages. Immunohistochemical studies demonstrate nuclear-localized survivin protein in epithelial cells bounding forming lumina in Canalicular and Terminal Bud Stage SMGs. CONCLUSIONS: Survivin is known to be a pro-survival and anti-apoptotic factor. Given that survivin translocation into the nucleus is required for the induction of entry into the cell cycle and the inhibition of apoptosis, our demonstration of nuclear-localized survivin protein in presumptive ductal and proacinar lumen-bounding cells suggests that survivin may be a key mediator of embryonic SMG epithelial cell survival