A teleoperation framework for mobile robots based on shared control

Mobile robots can complete a task in cooperation with a human partner. In this paper, a hybrid shared control method for a mobile robot with omnidirectional wheels is proposed. A human partner utilizes a six degrees of freedom haptic device and electromyography (EMG) signals sensor to control the mobile robot. A hybrid shared control approach based on EMG and artificial potential field is exploited to avoid obstacles according to the repulsive force and attractive force and to enhance the human perception of the remote environment based on force feedback of the mobile platform. This shared control method enables the human partner to tele-control the mobile robot’s motion and achieve obstacles avoidance synchronously. Compared with conventional shared control methods, this proposed one provides a force feedback based on muscle activation and drives the human partners to update their control intention with predictability. Experimental results demonstrate the enhanced performance of the mobile robots in comparison with the methods in the literature

Existence and stability of periodic solution of a Lotka–Volterra predator–prey model with state dependent impulsive effects

AbstractAccording to biological and chemical control strategy for pest, we investigate the dynamic behavior of a Lotka–Volterra predator–prey state-dependent impulsive system by releasing natural enemies and spraying pesticide at different thresholds. By using Poincaré map and the properties of the Lambert W function, we prove that the sufficient conditions for the existence and stability of semi-trivial solution and positive periodic solution. Numerical simulations are carried out to illustrate the feasibility of our main results

Electrochemical Performances of Electroactive Nano-Layered Organic-Inorganic Perovskite Containing Trivalent Iron Ion and its Use for a DNA Biosensor Preparation

A steady nano organic-inorganic perovskite hybrid with [H23-AMP]3/2Fe(CN)6 (3-AMP = 3-methylaminopyridine) was prepared in the air. The structure is an unusual layered organic-inorganic type. The resulting hybrid enveloped in paraffin to prepare [H23-AMP]3/2Fe(CN)6 paste electrode (HPE) shows good electrochemical activity and a couple of oxidation and reduction peaks with potential of cyclic voltammometry (CV) at around 440 mV and 30 mV. Compared with that on CPE, oxidation potential of Fe(CN)63− on HPE shifts negatively 259.7 mV and that of reduction shifts positively 338.7 mV, which exhibits that [H23-AMP]3/2Fe(CN)6 can accelerate the electron-transfer to improve the electrochemical reaction reversibility. Such characteristics of [H23-AMP]3/2Fe(CN)6 have been employed to prepare the DNA biosensor. The single-strand DNA (ssDNA) and double-strand DNA (dsDNA) immobilized on HPE, respectively, can improve the square wave voltammometry (SWV) current and SWV potential shifts positively. The effect of pH was evaluated. And there is hybridization peak on SWV curve using HPE immobilized ssDNA in the complementary ssDNA solution. And HPE immobilized ssDNA can be utilized to monitor the DNA hybridization and detect complementary ssDNA, covering range from 3.24 × 10−7 to 6.72 × 10−5 g/mL with detection limit of 1.57 × 10−7 g/mL. The DNA biosensor exhibits a good stability and reproducibility

Dynamic analysis of a fractional-order single-species model with diffusion

In this paper, we consider a fractional-order single-species model which is composed of several patches connected by diffusion. We first prove the existence, uniqueness, non-negativity and boundedness of solutions for the model, as desired in any population dynamics. Moreover, we also obtain some sufficient conditions ensuring the existence and uniform asymptotic stability of the positive equilibrium point for the investigated system. Finally, numerical simulations are presented to demonstrate the validity and feasibility of the theoretical results

Cucurbitacin E inhibits the Yes‑associated protein signaling pathway and suppresses brain metastasis of human non‑small cell lung cancer in a murine model.

Human non‑small cell lung cancer (NSCLC) is associated with an extremely poor prognosis especially for the 40% of patients who develop brain metastasis, and few treatment strategies exist. Cucurbitacin E (CuE), an oxygenated tetracyclic triterpenoid isolated from plants particularly of the family Cucurbitaceae, has shown anti‑tumorigenic properties in several types of cancer, yet the mechanism remains unclear. Yes‑associated protein (YAP), a main mediator of the Hippo signaling pathway, promotes tumorigenesis, drug resistance and metastasis in human NSCLC. The present study was designed to ascertain whether CuE inhibits YAP and its downstream gene expression in the human NSCLC cell lines H2030‑BrM3 (K‑rasG12C mutation) and PC9‑BrM3 (EGFRΔexon19 mutation), which have high potential for brain metastasis. The efficacy of CuE in suppressing brain metastasis of H2030‑BrM3 cells in a murine model was also investigated. It was found that after CuE treatment in H2030‑BrM3 and PC9‑BrM3 cells, YAP protein expression was decreased, and YAP signaling GTIIC reporter activity and expression of the downstream genes CTGF and CYR61 were significantly (P<0.01) decreased. CuE treatment also reduced the migration and invasion abilities of the H2030‑BrM3 and PC9‑BrM3 cells. Finally, our in vivo study showed that CuE treatment (0.2 mg/kg) suppressed H2030‑BrM3 cell brain metastasis and that mice treated with CuE survived longer than the control mice treated with 10% DMSO (P=0.02). The present study is the first to demonstrate that CuE treatment inhibits YAP and the signaling downstream gene expression in human NSCLC in vitro, and suppresses brain metastasis of NSCLC in a murine model. More studies to verify the promising efficacy of CuE in inhibiting brain metastasis of NSCLC and various other cancers may be warranted

Inhibition of cyclin-dependent kinase 7 down-regulates yes-associated protein expression in mesothelioma cells.

Cyclin-dependent kinase 7 (CDK7) is a protein kinase that plays a major role in transcription initiation. Yes-associated protein (YAP) is a main effector of the Hippo/YAP signalling pathway. Here, we investigated the role of CDK7 on YAP regulation in human malignant pleural mesothelioma (MPM). We found that in microarray samples of human MPM tissue, immunohistochemistry staining showed correlation between the expression level of CDK7 and YAP (n = 70, r = .513). In MPM cells, CDK7 expression level was significantly correlated with GTIIC reporter activity (r = .886, P = .019). Inhibition of CDK7 by siRNA decreased the YAP protein level and the GTIIC reporter activity in the MPM cell lines 211H, H290 and H2052. Degradation of the YAP protein was accelerated after CDK7 knockdown in 211H, H290 and H2052 cells. Inhibition of CDK7 reduced tumour cell migration and invasion, as well as tumorsphere formation ability. Restoration of the CDK7 gene rescued the YAP protein level and GTIIC reporter activity after siRNA knockdown in 211H and H2052 cells. Finally, we performed a co-immunoprecipitation analysis using an anti-YAP antibody and captured the CDK7 protein in 211H cells. Our results suggest that CDK7 inhibition reduces the YAP protein level by promoting its degradation and suppresses the migration and invasion of MPM cells. Cyclin-dependent kinase 7 may be a promising therapeutic target for MPM

Current Situation and Development Trend of Mobile Communication Systems

This paper introduces the development background of mobile communication and the development of mobilecommunication. It introduces the application principle, network structure, main technology, the advantages anddisadvantages of the three generations of mobile communication system respectively, and introduces the currentthird generation mobile communication system, including its technical support and research direction, analysis andcomparison of the European WCDMA system, the United States CDMA2000 system and China's TD-SCDMA systemtechnical characteristics. Finally, the development trend and prospect of future mobile communication system arediscussed

Inhibition of yes-associated protein suppresses brain metastasis of human lung adenocarcinoma in a murine model.

Yes-associated protein (YAP) is a main mediator of the Hippo pathway and promotes cancer development and progression in human lung cancer. We sought to determine whether inhibition of YAP suppresses metastasis of human lung adenocarcinoma in a murine model. We found that metastatic NSCLC cell lines H2030-BrM3(K-rasG12C mutation) and PC9-BrM3 (EGFRΔexon19 mutation) had a significantly decreased p-YAP(S127)/YAP ratio compared to parental H2030 (K-rasG12C mutation) and PC9 (EGFRΔexon19 mutation) cells (P < .05). H2030-BrM3 cells had significantly increased YAP mRNA and expression of Hippo downstream genes CTGF and CYR61 compared to parental H2030 cells (P < .05). Inhibition of YAP by short hairpin RNA (shRNA) and small interfering RNA (siRNA) significantly decreased mRNA expression in downstream genes CTGF and CYR61 in H2030-BrM3 cells (P < .05). In addition, inhibiting YAP by YAP shRNA significantly decreased migration and invasion abilities of H2030-BrM3 cells (P < .05). We are first to show that mice inoculated with YAP shRNA-transfected H2030-BrM3 cells had significantly decreased metastatic tumour burden and survived longer than control mice (P < .05). Collectively, our results suggest that YAP plays an important role in promoting lung adenocarcinoma brain metastasis and that direct inhibition of YAP by shRNA suppresses H2030-BrM3 cell brain metastasis in a murine model

The impact of an abandoned mercury mine on the environment in the Xiushan region, Chongqing, southwestern China

Mercury contamination is a serious problem in the Hg mining area of Xiushan County, Chongqing, southwestern China. The concentrations of total mercury (THg) and methylmercury (MeHg) in paddy soil, surface water, and rice (grain) samples were determined to investigate the regional distribution of Hg contamination. Simultaneously, gaseous elemental Hg (GEM) in ambient air near the sampling sites was measured. The total Hg concentrations in surface water were highly elevated, ranging from 13 to 2390 ng/L, and the total MeHg concentrations varied between 0.17 and 1.1 ng/L. The dissolved Hg and MeHg concentrations in surface water ranged from 4.7 to 470 ng/L and 0.14–0.35 ng/L, respectively. High THg and MeHg concentrations were also obtained in paddy soils from mining areas, ranging from 0.45 to 68 μg/g and 0.13–4.8 ng/g, respectively. Similar to the high concentrations in water and soil, the THg concentration in rice (grain) ranged from 4.7 to 550 ng/g and MeHg from 2.9 to 26 ng/g. Elevated Hg concentrations in rice, as a staple food of local residents, confirmed that rice consumption could be a vital pathway for MeHg exposure to native people. Humic acid and fulvic acid had significant correlations with soil MeHg, implying that they have important roles that influence MeHg production in soil. The spatial distribution characteristics of Hg and MeHg pollution in the local environment indicated their origins from historic Hg mining sites in the Xiushan area.acceptedVersio