616 research outputs found

    Self-Supervised Deep Visual Odometry with Online Adaptation

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    Self-supervised VO methods have shown great success in jointly estimating camera pose and depth from videos. However, like most data-driven methods, existing VO networks suffer from a notable decrease in performance when confronted with scenes different from the training data, which makes them unsuitable for practical applications. In this paper, we propose an online meta-learning algorithm to enable VO networks to continuously adapt to new environments in a self-supervised manner. The proposed method utilizes convolutional long short-term memory (convLSTM) to aggregate rich spatial-temporal information in the past. The network is able to memorize and learn from its past experience for better estimation and fast adaptation to the current frame. When running VO in the open world, in order to deal with the changing environment, we propose an online feature alignment method by aligning feature distributions at different time. Our VO network is able to seamlessly adapt to different environments. Extensive experiments on unseen outdoor scenes, virtual to real world and outdoor to indoor environments demonstrate that our method consistently outperforms state-of-the-art self-supervised VO baselines considerably.Comment: Accepted by CVPR 2020 ora

    Delivery of MicroRNAs by plant virus-based nanoparticles to functionally alter the osteogenic differentiation of human mesenchymal stem cells

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    MicroRNA-26a (miR-26a) has been verified to promote osteogenic differentiation of mesenchymal stem cells in recent years. The main obstacles to its application in bone regeneration are instability in the physiological environment and low efficiency of cellular membrane penetration. To overcome these problems, we constructed a novel plant virus gene delivery system based on Cowpea chlorotic mottle virus (CCMV). By encapsulating miR-26a with purified capsid protein (CP) dimers derived from CCMV, CP-miR-26a (CP26a) virus-like particles (VLPs) were obtained. CP26a retained a structure similar to the native CCMV and protected miR-26a from digestion with its exterior CP. Moreover, CP26a featured similar cellular uptake efficiency, osteogenesis promotion ability, and better biocompatibility compared with Lipofectamine2000-miR-26a (lipo26a), which indicated a promising prospect for CCMV as a novel gene delivery system.</p

    Far-Field Tunable Nano-focusing Based on Metallic Slits Surrounded with Nonlinear-Variant Widths and Linear-Variant Depths of Circular Dielectric Grating

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    In this work, we design a new tunable nanofocusing lens by the linear-variant depths and nonlinear-variant widths of circular grating for far field practical applications. The constructively interference of cylindrical surface plasmon launched by the subwavelength metallic structure can form a subdiffraction-limited focus, and the focal length of the this structures can be adjusted if the each groove depth and width of circular grating are arranged in traced profile. According to the numerical calculation, the range of focusing points shift is much more than other plasmonic lens, and the relative phase of emitting light scattered by surface plasmon coupling circular grating can be modulated by the nonlinear-variant width and linear-variant depth. The simulation result indicates that the different relative phase of emitting light lead to variant focal length. We firstly show a unique phenomenon for the linear-variant depths and nonlinear-variant widths of circular grating that the positive change and negative change of the depths and widths of grooves can result in different of variation trend between relative phases and focal lengths. These results paved the road for utilizing the plasmonic lens in high-density optical storage, nanolithography, superresolution optical microscopic imaging, optical trapping, and sensing.Comment: 14pages,9figure

    A New ZrCuSiAs-Type Superconductor: ThFeAsN

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    We report the first nitrogen-containing iron-pnictide superconductor ThFeAsN, which is synthesized by a solid-state reaction in an evacuated container. The compound crystallizes in a ZrCuSiAs-type structure with the space group P4/nmm and lattice parameters a=4.0367(1) {\AA} and c=8.5262(2) {\AA} at 300 K. The electrical resistivity and dc magnetic susceptibility measurements indicate superconductivity at 30 K for the nominally undoped ThFeAsN.Comment: 6 pages, 4 figures, 1 tabl

    Characterization of a newly isolated green microalga Scenedesmus sp. as a potential source of biodiesel

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    An oil-producing microalga SP-01 belonging to the genus Scenedesmus was shown to be able to grow on a media containing 5 to 30 g L-1 NaCl. Under mixotrophic condition, the maximum cell dry weight of 3.1 g L-1 and specific growth rate of 0.034 h-1 were obtained at 0.5 g L-1 NaNO3 and 6 g L-1 acetate. The effects of salinity on the biomass, lipid, and carotenoid productions of the alga SP-01 in mixotrophic mode were investigated. The biomass productivity increased with increasing NaNO3 concentrations, and addition of NaCl resulted in a higher biomass while NaNO3 was present. The maximum lipid content was obtained while no NaNO3 and NaCl was added, and the lipid content decreased with increasing NaNO3 concentrations or addition of NaCl. The maximum lipid productivities of 67.44 to 68.44 mg L-1day-1 were obtained while NaNO3 and NaCl were not added or while 20 g L-1 NaCl and 0.13 g L-1 NaNO3 were added. The algal lipid was mainly composed of C16 and C18 fatty acids accounting for more than 90% of total fatty acids. Furthermore, lutein and astaxanthin were the main carotenoids.Key words: Halotolerant, microalga, Scenedesmus sp., mixotrophic culture, lipid, carotenoid

    Association between the triglyceride to high-density lipoprotein cholesterol ratio and the risk of type 2 diabetes mellitus among Chinese elderly: The Beijing Longitudinal Study of Aging

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    Objective: Time-dependent covariates are generally available as longitudinal data were collected periodically in the cohort study. To examine whether time-dependent triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio could predict the future risk of type 2 diabetes mellitus (T2DM) and assess its potential impact on the risk of T2DM incidence. Research design and methods: This study enrolled 1460 participants without T2DM aged 55 or above in 1992 in the Beijing Longitudinal Study of Aging during 25 years. The questionnaire data were collected in nine surveys from 1992 to 2017. Physical examination and blood laboratory tests including TG and HDL-C concentrations were measured in five surveys. Incident T2DM cases were confirmed via a self-reported history of T2DM or the fasting plasma glucose level. Results: 119 new cases of T2DM were identified. In the Cox regression analysis with time-dependent TG/HDL-C ratios and covariates, the adjusted hazard ratios (95% confidence interval) of T2DM incidence were 1.90 (1.12 to 3.23), 2.75 (1.58 to 4.80) and 2.84 (1.69 to 4.77), respectively, for those with TG/HDL-C ratios (both TG and HDL-C were expressed in millimole per liter) in the ranges of 0.87-1.30, 1.31-1.74 and ≥ 1.75, compared with individuals with TG/HDL-C ratios \u3c 0.87. The similar results of subdistribution hazard ratios were obtained by performing the Fine-Gray model with time-dependent TG/HDL-C ratios. This positive association and the statistically significant trend with increased risk of T2DM incidence in the three categories of elevated TG/HDL-C ratio was confirmed by multiple sensitivity analyses. Furthermore, the T2DM discriminatory power of TG/HDL-C ratio combining with other risk factors was moderately high. Conclusions: We found that time-dependent TG/HDL-C ratios were positively associated with the risk of T2DM risk. The elevated TG/HDL-C ratios increased the future risk of T2DM incidence. Lowering the TG/HDL-C ratio could assist in the prevention of diabetes for older adults. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ

    Association between high-density lipoprotein cholesterol and type 2 diabetes mellitus among Chinese: The Beijing longitudinal study of aging

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    Background: Some previous studies on different populations have yielded inconsistent findings with respect to the relationship between levels of high-density lipoprotein cholesterol (HDL-C) and future type 2 diabetes mellitus (T2DM) incidence. This study was designed to gain further insight into this relationship through a cohort study with a 25-year follow-up duration. Methods: In total, 1462 individuals that were 55 years of age or older and were free of T2DM at baseline were enrolled in the present study. T2DM incidence among this study population was detected through self-reported diagnoses or the concentration of fasting plasma glucose. The data were derived from nine surveys conducted from 1992 to 2017. The correlation between HDL-C levels and the T2DM risk was assessed through Cox proportional-hazards model and proportional hazards model for the sub-distribution with time-dependent variables. Results: Over the follow-up period, 120 participants were newly diagnosed with new-onset T2DM. When research participants were separated into four groups on the basis for quartiles of their levels of HDL-C measured at baseline, and incidence of diabetes declined with higher baseline HDL-C levels at 12.60, 9.70, 5.38, and 5.22 per 1000 person-years, respectively. Adjusted hazard ratios (HRs) were 0.98 (95% confidence interval [CI]: 0.62–1.55), 0.48 (95% CI: 0.27–0.85) and 0.44 (95% CI: 0.25–0.80) for individuals with HDL-C levels within the 1.15–1.39, 1.40–1.69, and ≥ 1.70 mmol/L ranges relative to participants with HDL-C levels \u3c 1.15 mmol/L. Multiple sensitivity analyses similarly revealed reduced risk of diabetes incidence with increased HDL-C levels. Incorporating the levels of HDL-C into a multivariate model significantly enhanced the overall power of the predictive model (P values were 0.0296, 0.0011, respectively, for 5- and 10-year risk of diabetes). Conclusions: Levels of HDL-C were independently and negatively associated with the risk of the new-onset T2DM among middle-aged and elderly Chinese

    SHEARING BEHAVIOR OF STRUCTURAL INSULATED PANEL WALL SHELLED WITH BAMBOO SCRIMBER

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    In this study, shearing behavior of a structural insulated panel (SIP) wall, which consisted of a Styrofoam core board, shell panel of bamboo scrimber, and frame of Spruce–Pine–Fir dimension lumber, was tested under monotonic and cyclic loads. Results showed that the SIP wall failed at similar positions under two loading modes, although more serious destruction occurred under cyclic than monotonic load. There was a linear relationship between load and displacement at the initial loading stage, which indicated that the wall worked under the elastic state. At a later loading stage, bearing capacity and rigidity decreased as a result of wall slip. Shearing strength under monotonic and cyclic loads was 20.0 and 15.8 kNm-1, respectively, which met the requirement of the standard code for design of timber structures. Energy consumption of the SIP wall covered with bamboo scrimber was 11,556.6 Jm-1

    STAT1 as a downstream mediator of ERK signaling contributes to bone cancer pain by regulating MHC II expression in spinal microglia

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    Major histocompatibility class II (MHC II)-specific activation of CD4+ T helper cells generates specific and persistent adaptive immunity against tumors. Emerging evidence demonstrates that MHC II is also involved in basic pain perception; however, little is known regarding its role in the development of cancer-induced bone pain (CIBP). In this study, we demonstrate that MHC II expression was markedly induced on the spinal microglia of CIBP rats in response to STAT1 phosphorylation. Mechanical allodynia was ameliorated by either pharmacological or genetic inhibition of MHC II upregulation, which was also attenuated by the inhibition of pSTAT1 and pERK but was deteriorated by intrathecal injection of IFNγ. Furthermore, inhibition of ERK signaling decreased the phosphorylation of STAT1, as well as the production of MHC II in vivo and in vitro. These findings suggest that STAT1 contributes to bone cancer pain as a downstream mediator of ERK signaling by regulating MHC II expression in spinal microglia

    Significance of HER2 protein expression and HER2 gene amplification in colorectal adenocarcinomas

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    BACKGROUND: Human epidermal growth factor receptor 2 (HER2) is an oncogenic driver, and a well-established therapeutic target in breast and gastric cancers. While the role of HER2 as a prognostic biomarker in colorectal adenocarcinomas (CRCs) remains uncertain, its relevance as a therapeutic target has been established. We undertook the present study to evaluate the frequency of HER2 expression in CRC and to correlate it with various clinicopathological variables. AIM: To correlate HER2 protein expression and METHODS: About 1195 consecutive surgically resected CRCs were analyzed by immunohistochemical staining (IHC) to assess HER2 protein expression, and 141 selected tumors were further evaluated by fluorescence RESULTS: HER2 IHC scores of 3+, 2+, 1+, and 0 were seen in 31 (2.6%), 105 (8.8%), 475 (39.7%), and 584 (48.9%) tumors, respectively. CONCLUSION: HER2 protein levels are correlated with clinical outcomes, and positive HER2 expression as measured by IHC confers a worse prognosis in those patients 65 years old or younger with tubular adenocarcinomas
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