14 research outputs found

    Robust passivity-based dynamical systems for compliant motion adaptation

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    Motivated by human compliant behaviors during interacting with unknown environments and how motions and impedance to are adapted skilfully complete a task, this article develops a motion planning scheme that is capable of generating a compliant trajectory online such that tracking desired contacting forces under a predefined motion task. First, an improved dynamical system (DS) is designed to generate an adaptive compliant scanning trajectory online from the original DS in terms of the contact forces and the desired scanning forces. Inspired by passivity analysis for the robot control system, a robust term is formulated to guarantee stability by considering the balance between environmental and robotic energy. Furthermore, we develop a state-constrained controller based on barrier Lyapunov function to track the compliant DS motion and to ensure safety during scanning for the patient. Finally, comparative simulations are conducted to validate the general compliant capability of the proposed framework. We also instantiate our methodology through a use case of liver ultrasound scanning to demonstrate the stable and dynamic force tracking performance

    Odor Discrimination by Similarity Measures of Abstract Odor Factor Maps from Electronic Noses

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    The aim of this study is to improve the discrimination performance of electronic noses by introducing a new method for measuring the similarity of the signals obtained from the electronic nose. We constructed abstract odor factor maps (AOFMs) as the characteristic maps of odor samples by decomposition of three-way signal data array of an electronic nose. A similarity measure for two-way data was introduced to evaluate the similarities and differences of AOFMs from different samples. The method was assessed by three types of pipe and powder tobacco samples. Comparisons were made with other techniques based on PCA, SIMCA, PARAFAC and PARAFAC2. The results showed that our method had significant advantages in discriminating odor samples with similar flavors or with high VOCs release

    Strontium ranelate inhibits wear particle-induced aseptic loosening in mice

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    The imbalance between bone formation and osteolysis plays a key role in the pathogenesis of aseptic loosening. Strontium ranelate (SR) can promote bone formation and inhibit osteolysis. The aim of this study was to explore the role and mechanism of SR in aseptic loosening induced by wear particles. Twenty wild-type (WT) female C57BL/6j mice and 20 sclerostin-/- female C57BL/6j mice were used in this study. Mice were randomly divided into four groups: WT control group, WT SR group, knockout (KO) control group, and KO SR group. We found that SR enhanced the secretion of osteocalcin (0.72±0.007 in WT control group, 0.98±0.010 in WT SR group, P=0.000), Runx2 (0.34±0.005 in WT control group, 0.47±0.010 in WT SR group, P=0.000), β-catenin (1.04±0.05 in WT control group, 1.22±0.02 in WT SR group, P=0.000), and osteoprotegerin (OPG) (0.59±0.03 in WT control group, 0.90±0.02 in WT SR group, P=0.000). SR significantly decreased the level of receptor activator for nuclear factor-κB ligand (RANKL) (1.78±0.08 in WT control group, 1.37±0.06 in WT SR group, P=0.000) and improved the protein ratio of OPG/RANKL, but these effects were not observed in sclerostin-/- mice. Our findings demonstrated that SR enhanced bone formation and inhibited bone resorption in a wear particle-mediated osteolysis model in wild-type mice, and this effect relied mainly on the down-regulation of sclerostin levels to ameliorate the inhibition of the canonical Wnt pathway

    A Prognostic Model Based on Nutritional Risk Index in Operative Breast Cancer

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    Background: The nutritional risk index (NRI) is an independent prognostic factor for overall survival in various cancers, but its prognostic value in breast cancer remains unclear. This study aimed to explore the relationship between the NRI and overall survival (OS) in breast cancer and to develop a predictive nomogram. Methods: We retrospectively enrolled 1347 breast cancer patients who underwent mastectomy or lumpectomy between January 2011 and November 2012. Using a cutoff value of 110.59, patients were divided into a high-NRI group and a low-NRI group. OS was compared between the two groups. Clinicopathological factors independently associated with survival were used to construct a predictive nomogram. Results: Of the 1347 patients, 534 patients were classified as high NRI and 813 as low NRI. OS was significantly shorter in low-NRI patients. The 3- and 5-year OS rates were 87.3% and 73.4%, respectively, in the high-NRI group whereas they were 83.0% and 67.2%, respectively, in the low-NRI group. Cox regression analysis found that histopathological type, tumor size, lymph node status, progesterone receptor (PR) status, Ki-67, and NRI were independently associated with OS. Conclusions: NRI is an independent prognostic factor of OS in breast cancer patients. The proposed nomogram model may be a useful tool for individualized survival prediction

    Model construction of Chinese preservice physical education teachers’ perception of social media: A grounded theory approach

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    (1) Background: Pre-service physical education teachers commonly embrace social media for multiple purposes. However, little is known about their perception of social media, which could affect the appropriate use of social media in their future professional work. This study aims to explore a theoretical model of how pre-service physical education teachers perceive social media in order to provide a basis for educators to guide their appropriate use of social media. (2) Methods: Qualitative data were collected in diverse ways, mainly from interviews. Seventeen Chinese preservice physical education teachers were selected as participants by a purposive sampling technique. The interview questions focused on participants’ motivation, expectations, and experiences in social media usage. Grounded theory was used to analyze the data by ROST CM and Nvivo 12. (3) Results: The perception of social media among teachers includes three subsidiary categories made up of 10 sub-categories, 70 concepts, and 307 labels. The three categories are (a) value perception, including the perspective of intelligent function, interaction, and rich information, (b) risk perception, involving psychological risk, information risk and privacy risk and (c) overall perception, like development trends, current status and basic elements. (4) Conclusions: Chinese preservice physical education teachers perceive social media as having similarities and differences compared to other countries. Future research should consider a large sample survey to revise and verify the initial exploration of perception and study diverse groups of teachers’ perceptions of social media.</p

    Identification of Optimal Reference Genes for Expression Analysis in Radish (Raphanus sativus L.) and Its Relatives Based on Expression Stability

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    Radish (Raphanus sativus) is an important cruciferous root crop with a close relationship to Chinese cabbage (Brassica rapa). RT-qPCR is used extensively to evaluate the expression levels of target genes, and accurate measurement of target gene expression with this method is determined by the valid reference genes used for data nomalization in different experimental conditions. Screening for appropriate reference genes with stable expression based on RT-qPCR data is important for gene expression and functional analysis research in radish and its relatives. However, many researches have thought that almost no single reference gene is widely suitable for all experimental conditions, and few researchers have paid attention to the validation of reference genes in radish gene expression analysis. In the present study, 12 candidate reference genes were selected for analysis. Their expression in 28 samples, including 20 radish samples from different organs and conditions, four Chinese cabbage organs and four organs of their distant hybrid, was assessed by RT-qPCR and then five software tools—ΔCt, geNorm, NormFinder, BestKeeper and RefFinder—were used to compare their expression stability. The results showed that the most suitable reference genes were different in different organs and conditions. GAPDH, DSS1, and UP2 were optimal reference genes for gene expression analysis in all organs and conditions in radish. UPR, GSNOR1, and ACTIN2/7 were the most stable reference genes in different radish organs. UP2 and GAPDH were suitable reference genes for radish pistil development studies. RPII, UBC9, and GAPDH had the most stable expression in radish under various stresses. DSS1, UP2, and TEF2 were the optimal reference genes for Chinese cabbage organs, whereas TUA was optimal for the distant hybrid. UP2, and TEF2 were appropriate reference genes for all of the samples together. The optimal reference genes we identified, UP2, GAPDH, UPR, and GSNOR1 were verified by normalizing the expression patterns of YAB3, RPL, and FUL. These results will provide important information for selecting target reference genes in different research contexts and improve the accuracy and precision of gene expression analysis for radish, Chinese cabbage and their distant hybrid

    Electronic and Optoelectronic Monolayer WSe<sub>2</sub> Devices via Transfer-Free Fabrication Method

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    Monolayer transition metal dichalcogenides (TMDs) have drawn significant attention for their potential applications in electronics and optoelectronics. To achieve consistent electronic properties and high device yield, uniform large monolayer crystals are crucial. In this report, we describe the growth of high-quality and uniform monolayer WSe2 film using chemical vapor deposition on polycrystalline Au substrates. This method allows for the fabrication of continuous large-area WSe2 film with large-size domains. Additionally, a novel transfer-free method is used to fabricate field-effect transistors (FETs) based on the as-grown WSe2. The exceptional metal/semiconductor interfaces achieved through this fabrication method result in monolayer WSe2 FETs with extraordinary electrical performance comparable to those with thermal deposition electrodes, with a high mobility of up to ≈62.95 cm2 V−1 s−1 at room temperature. In addition, the as-fabricated transfer-free devices can maintain their original performance after weeks without obvious device decay. The transfer-free WSe2-based photodetectors exhibit prominent photoresponse with a high photoresponsivity of ~1.7 × 104 A W−1 at Vds = 1 V and Vg = −60 V and a maximum detectivity value of ~1.2 × 1013 Jones. Our study presents a robust pathway for the growth of high-quality monolayer TMDs thin films and large-scale device fabrication
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