On the Generalized Bertrand Curves in Euclidean NN-spaces

In this article, we give a necessary condition for a $C^\infty$-special Frenet curve in $\mathbb{R}^{N}$ being a generalized Bertrand curve

Enhancing classroom management through parental involvement by using social networking apps

The purpose of this study is to explore the classroom management effectiveness enhancement by using social networking apps through electronic devices such as smartphones, tablet computers, and personal computers, as well as the role of parental involvement. Quantitative research was conducted, and the Structural Equation Modelling (SEM) statistical technique applied. From 15 different Changhua County primary schools in Taiwan, 411 teachers were chosen using stratified random sampling in proportion to the size and location of schools. Each teacher was invited to fill out a questionnaire. A total of 403 (98.05%) questionnaires were returned, with 382 (92.94%) considered valid. In order to confirm the statistical results, a focused group interview was also conducted. The effects of the behaviour intention of using Line, parental involvement, and classroom management effectiveness were all found to be positively associated with one another. Moreover, the mediating role of parents in the relationship between the behaviour intention of using Line and classroom management effectiveness enhancement was also supported and confirmed.Keywords: behaviour intention; classroom management effectiveness; parental involvement; social networking apps; Taiwan’s primary school

THE DESIGN MODEL OF MICRO END-MILLS MADE BY USING THE FINITE ELEMENT METHOD

The green processing technology has been brought to the focus of attention around the world. The development and application of green cutting depend on the machine and cutting tool technology progress, in so far as the development of cutting tool technology has quite a big influence. The study was focused on the simulation analysis model for micro milling SKD61 tool steel developed by the finite element method. First, because the impact of the effective rake angle on the oblique cutting model is equivalent to that of the rake angle on the orthogonal cut model, the complex tool geometry of an end-mill will be simplified to the orthogonal cutting model. Using the Taguchi method, the FEM simulation of orthogonal cutting operation was performed under different cutting speeds, cutting depths, effective rake angles and relief angles were modified. The cutting force, tool maximum temperature, tool maximum temperature and tip distance, and the contact length of tool and chip are the major performance indexes of micro milling process. Finally, the multiple cutting performance characteristic resulting from the grey relational analysis reveals that the influencing priority ranks for micro end-mills made of SKD61 tool steel are cutting speed, effective rake angle, relief angle, and cutting depth. The FEM model is suitable for simulating the cutting performance of micro cutting process, and can also be used as a design base for micro endmills

Leveling Maintenance Mechanism by Using the Fabry-Perot Interferometer with Machine Learning Technology

This study proposes a method for maintaining parallelism of the optical cavity of a laser interferometer using machine learning. The Fabry-Perot interferometer is utilized as an experimental optical structure in this research due to its advantage of having a brief optical structure. The supervised machine learning method is used to train algorithms to accurately classify and predict the tilt angle of the plane mirror using labeled interference images. Based on the predicted results, stepper motors are fixed on a plane mirror that can automatically adjust the pitch and yaw angles. According to the experimental results, the average correction error and standard deviation in 17-grid classification experiment are 32.38 and 11.21 arcseconds, respectively. In 25-grid classification experiment, the average correction error and standard deviation are 19.44 and 7.86 arcseconds, respectively. The results show that this parallelism maintenance technology has essential for the semiconductor industry and precision positioning technology

Comparative study of the persistence of anti-HIV activity of deoxynucleoside HIV reverse transcriptase inhibitors after removal from culture

<p>Abstract</p> <p>Background</p> <p>Most in vitro assays of drug potency may not adequately predict the performance in vivo. Methods to assess the persistence of antiviral activity of deoxynucleoside analogs, which require intracellular activation to the active metabolites that can persist in cells, will be important for designing dosages, combination regimens, and assessing treatment compliance. Using an HIV-IIIB/TZM-bl indicator cell culture system, we assessed the ability of an inhibitor to protect cells from infection and to delay viral rebound after removal of inhibitor from culture.</p> <p>Results</p> <p>The order of protection of cells from HIV-infection was 4'-Ed4T > LFD4C > DDI > D4T > 3TC > AZT > FTC > NVP. The fold-increase in EC₅₀to delay viral rebound was DDI < 4'-Ed4T < LFD4C < FTC < D4T < 3TC < NVP < AZT. The ranking of persistence of anti-HIV activity of the inhibitors based on the two-component assay was DDI > 4'-Ed4T > LFD4C > FTC = D4T > 3TC > NVP > AZT.</p> <p>Conclusion</p> <p>The persistence ranking was derived from assays based on measures of single viral replication-cycle and cumulative inhibition at multiple time-points. Therefore, a better indicator of the pharmacodynamic property of an inhibitor. The persistence of anti-HIV activity assay may complement in vitro potency assays to better predict in vivo performance of nucleoside analogs.</p

DCB-3503, a Tylophorine Analog, Inhibits Protein Synthesis through a Novel Mechanism

BACKGROUND: DCB-3503, a tylophorine analog, inhibits the growth of PANC-1 (human pancreatic ductal cancer cell line) and HepG2 (human hepatocellular cancer cell line) tumor xenografts in nude mice. The inhibition of growth leads to cancer cell differentiation instead of cell death. However, the mechanisms of action of tylophorine analogs is unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we show that DCB-3503 suppresses the expression of pro-oncogenic or pro-survival proteins with short half-lives, including cyclin D1, survivin, beta-catenin, p53, and p21, without decreasing their mRNA levels. Proteasome inhibitor reversed the inhibitory effect of DCB-3503 on expression of these proteins. DCB-3503 inhibited the incorporation of radiolabeled amino acid and thymidine, and to a much lesser degree of uridine, in a panel of cell lines. The mechanism of inhibition of protein synthesis is different from that of cycloheximide (CHX) as assayed in cell culture and HeLa in vitro translation system. Furthermore, in contrast to rapamycin, DCB-3503 does not affect protein synthesis through the mTOR pathway. DCB-3503 treatment shifts the sedimentation profiles of ribosomes and mRNAs towards the polysomal fractions while diminishing monosome abundance, indicative of the inhibition of the elongation step of protein synthesis. Preferential down regulation of several studied proteins under these conditions is likely due to the relative short half-lives of these proteins. CONCLUSION/SIGNIFICANCE: The inhibitory effect of DCB-3503 on translation is apparently distinct from any of the current anticancer compounds targeting protein synthesis. Translation inhibitors with novel mechanism could complement current chemotherapeutic agents for the treatment of human cancers and suppress the occurrence of drug resistance

Challenge and Prospect of Traditional Chinese Medicine in Depression Treatment

Current medication for depression is inadequate and far from ideal. Development of novel antidepressant drugs is a pressing task. The discovery of ketamine and related agents represents a new era in drug discovery for the rapid treatment of depression. Due to potential neurotoxicity, short-lasting efficacy, the limitation of a single target approach, and a limited role in depression prevention of these agents, additional approaches or drugs that exert synergy and compatibility, with the rapid-acting agents are required for better treatment of depression. Traditional Chinese Medicine (TCM) is a systems medicine and its clinical experience and integrated theory for diagnosis and treatment provides an alternative method of novel drug discovery in depression treatment. In TCM, there are numerous claimed effective antidepressant formulas, but comprehensive research and evidence-based clinical studies are required for their acceptance as a treatment. In this essay, we review current attempts in the discovery of new agents, TCM drug formulation, and TCM treatment of depression, and discuss the challenges and opportunities of TCM in the new era of antidepressant discovery. TCM could provide an important resource in the discovery of novel agents, assistance of the rapid-acting antidepressants, development of new agents for female patients, and the prevention of depression at its early stages. The study of depression in conjunction with TCM therefore not only provides an opportunity to scientifically evaluate the benefits and risks of TCM, but also accelerates the development of novel antidepressant agents by combining the principle of modern molecular medicine with the ideas of empirical systems medicine

Field-Free Switching in Symmetry Breaking Multilayers: The Critical Role of Interlayer Chiral Exchange

It is crucial to realize field-free, deterministic, current-induced switching in spin-orbit torque magnetic random-access memory (SOT-MRAM) with perpendicular magnetic anisotropy (PMA). A tentative solution has emerged recently, which employs the interlayer chiral exchange coupling or the interlayer Dzyaloshinskii-Moriya interaction (i-DMI) to achieve symmetry breaking. We hereby investigate the interlayer DMI in a Pt/Co multilayer system with orthogonally magnetized layers, using repeatedly stacked [Pt/Co]n structure with PMA, and a thick Co layer with in-plane magnetic anisotropy (IMA). We clarify the origin and the direction of such symmetry breaking with relation to the i-DMI effective field, and show a decreasing trend of the said effective field magnitude to the stacking number (n). By comparing the current-induced field-free switching behavior for both PMA and IMA layers, we confirm the dominating role of i-DMI in such field-free switching, excluding other possible mechanisms such as tilted-anisotropy and unconventional spin currents that may have arisen from the symmetry breaking