Channel Characteristics of Rail Traffic Tunnel Scenarios Based on Ray-Tracing Simulator

The tunnel scenario is a major rail communication scenario. In this paper, the radio channel characteristics of tunnel scenarios with different carrier frequencies, different distances between the transmitter (Tx) and receiver (Rx), and cross sections are simulated with a ray-tracing tool. Key parameters such as path loss, Rician K-factor, root mean square (RMS) delay spread, and angular spread are studied. According to the results, higher frequencies introduce larger path loss and the presence of the vehicle body increases the path loss by about 35 dB in the scenario; at the same time it will also cause the fluctuation and instability of the path loss. Besides, the influence of reflections from the side walls is significant on radio propagation. The channel experiences more severe fading in a narrow tunnel compared with others

ERK-estrogen receptor α signaling plays a role in the process of bone marrow mesenchymal stem cell-derived exosomes protecting against ovariectomy-induced bone loss

Abstract Background Exosomes derived from bone marrow mesenchymal stem cells (BMSC-Exos) are considered as candidates for osteoporosis (OP) therapy. Estrogen is critical in the maintenance of bone homeostasis. However, the role of estrogen and/or its receptor in BMSC-Exos treatment of OP, as well as its methods of regulation during this process remain unclear. Methods BMSCs were cultured and characterized. Ultracentrifugation was performed to collect BMSC-Exos. Transmission electron microscopy, nanoparticle tracking analysis, and western blotting were used to identify BMSC-Exos. We examined the effects of BMSC-Exos on the proliferation, osteogenic differentiation, mineralization, and cell cycle distribution of MG-63 cells. The protein expression of estrogen receptor α (ERα) and the phosphorylation of ERK were investigated through western blotting. We determined the effects of BMSC-Exos on the prevention of bone loss in female rats. The female Sprague–Dawley rats were divided into three groups: the sham group, ovariectomized (OVX) group, and the OVX + BMSC-Exos group. Bilateral ovariectomy was performed in the OVX and OVX + BMSC-Exos groups, while a similar volume of adipose tissue around the ovary was removed in the sham group. The rats in OVX group and OVX + BMSC-Exos group were given PBS or BMSC-Exos after 2 weeks of surgery. Micro-CT scanning and histological staining were used to evaluate the in vivo effects of BMSC-Exos. Results BMSC-Exos significantly enhanced the proliferation, alkaline phosphatase activity, and the Alizarin red S staining in MG-63 cells. The results of cell cycle distribution demonstrated that BMSC-Exos increased the proportion of cells in the G2 + S phase and decreased the proportion of cells in the G1 phase. Moreover, PD98059, an inhibitor of ERK, inhibited both the activation of ERK and the expression of ERα, which were promoted by administration of BMSC-Exos. Micro-CT scan showed that in the OVX + BMSC-Exos group, bone mineral density, bone volume/tissue volume fraction, trabecular number were significantly upregulated. Additionally, the microstructure of the trabecular bone was preserved in the OVX + BMSC-Exos group compared to that in the OVX group. Conclusion BMSC-Exos showed an osteogenic-promoting effect both in vitro and in vivo, in which ERK-ERα signaling might play an important role

Characterization of the Principal Constituents of Danning Tablets, a Chinese Formula Consisting of Seven Herbs, by an UPLC-DAD-MS/MS Approach

Danning Tablets are a traditional Chinese formula showing broad clinical applications in hepatobiliary diseases and containing a diversity of bioactive chemicals. However, the chemical profiling of the formula, which serves as the material foundation of its efficacy, is really a big challenge as Danning Tablets consist of seven herbs from different origins. An ultra-performance liquid chromatography coupled to diode array detection and electrospray ionization mass spectrometry (UPLC-DAD-ESI-MS/MS) approach was developed to characterize the principal polyphenol constituents in the formula. As a result, a total of 32 constituents, including 14 anthraquinones and their glucosides, four anthrones, two naphthalene glycosides, two stilbenes and 10 flavonoids were identified based on their retention time, UV absorption and MS/MS fragmentation patterns. The sources of these compounds were also illustrated. Most of the bioactive anthraquinone derivatives were found in Rhei Radix et Rhizoma or Polygoni Cuspidati Rhizoma et Radix, which are the Emperor drugs in the formula for its clinic usage. These findings indicate the merit of using this integrated UPLC-DAD-ESI-MS/MS approach to rapidly illustrate the chemical foundation of complex formulas. The present study will facilitate the quality control of Danning Tablet formulas as well as the individual herbs

Double-Edged Effects of Socially Responsible Human Resource Management on Employee Task Performance and Organizational Citizenship Behavior: Mediating by Role Ambiguity and Moderating by Prosocial Motivation

Previous literature has explored the positive effects of socially responsible human resource management (SRHRM) on employees, leaving potential dark sides largely ignored. By integrating situational-strength theory and motivation literature, this study investigates the double-edged effects of SRHRM on employee performance. Based on a sample of 314 employee–supervisor dyads from three companies, we found that SRHRM could increase employees’ organizational citizenship behavior (OCB) while decreasing their task performance through role-ambiguity mediation. Interestingly, prosocial motivation serves as a significant moderator in strengthening the positive relationship between SRHRM and OCB and the negative association between SRHRM and task performance. Finally, we discuss the theoretical and practical implications of how managers should conduct SRHRM practices among employees

Correlation between Pre-treatment Anemia and Prognosis in Non-small Cell Lung Cancer Patients

Background and objective The patients with non-small cell lung cancer (NSCLC) might contract anemia, however, whether anemia is one of the independent prognostic factors to the patients with NSCLC is still controversial. So the aim of this study is to investigate the correlation between anemia and overall survival (OS) in patients with NSCLC. Methods 1 018 patients with operable NSCLC were retrospectively analyzed in our hospital from January 2000 to December 2008. Results The occurrence of anemia before operation was 252/1 018 (24.1%). The OS in NSCLC patients without anemia was (2 425.98±50.03) days, and the OS in patients with anemia was (2 107.15±93.86) days. There was significant difference in the OS between them (P=0.001). The patients with anemia in stage I had shorter survival time than those without anemia (P < 0.001). But there was no difference in other stage patients. TNM stage, gender, tumor size and lymph nodes metastasis were correlated with OS using Cox regression analysis. Conclusion Anemia is correlated with survival in operable NSCLC patients. Moreover, it is an independent prognostic factor in NSCLC patients with stage I

A centimeter scale self-standing two-dimensional ultra-thin mesoporous platinum nanosheet

Here, we report the unprecedented synthesis of centimeter scale self-standing mesoporous Pt nanosheets. Due to solvent evaporation, spherical micelles made of poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-P2VP-PEO) self-assemble in a well-ordered fashion, over the entire surface of the substrate, and confined within an ultra-thin layer. Metal deposition around the micelles is carried out through a two-step reduction process using two different reducing agents. After removing the micelles and substrate, a continuous self-standing ultra-thin mesoporous Pt nanosheet can be obtained (∼15 nm thick). Due to several unique porous structural features, including abundant active sites, high surface area, and long-range orthogonally ordered pores, the obtained material is expected to deliver high performance in a wide range of electrochemical applications. This novel synthetic strategy opens a new route to design and control novel 2D mesoporous metal nanosheets with various functions