22 research outputs found

    Influence of Local Deformation Mode of Cable-Stayed Bridge on Unballasted Tracks: Experimental Research

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    The complex local deformation modes of the cable-stayed bridge influence the deformation characteristics of the unballasted tracks laid on it. In this work, a large-scale segment model of a cable-stayed bridge was fabricated, and the maximum upward bending deformation mode of the cable-stayed bridge was realized by multipoint loading on the segment model to study the deformation behaviors of the unballasted tracks. Experimental results indicated that the nonlinear behaviors of the rubber isolation layers are apparent with the loading increased, and the interlayer behaviors of the unballasted track can be improved by the rubber isolation layer. Besides, the relative tensile deformations at interlayers of the unballasted track are inevitable. It is noted that no void and silt form at interlayers of the unballasted tracks with rubber isolation layers due to the precompressions of the rubber material. However, it is entirely possible to produce some diseases such as voids and silts at interlayers of the unballasted track with the geotextile isolation layers paved on the cable-stayed bridge. Furthermore, it is feasible to use the elastic isolation layer to improve the interlayer deformation characteristics because a particular elastic buffer is provided at interlayers of the unballasted track

    Formal Total Synthesis of (±)-Lycojaponicumin C

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    The formal total synthesis of (±)-lycojaponicumin C has been accomplished. Key transformations include a Rh-catalyzed formal [3 + 2] cycloaddition reaction to construct the bicyclic [3.3.0] scaffold bearing two vicinal quaternary carbon centers, a stereoselective γ-hydroxyl directed Michael addition to introduce the vinyl group at a bulky position, and a late-stage ring-closing metathesis reaction to form the cyclohexanone ring

    Formal Total Synthesis of (±)-Lycojaponicumin C

    No full text
    The formal total synthesis of (±)-lycojaponicumin C has been accomplished. Key transformations include a Rh-catalyzed formal [3 + 2] cycloaddition reaction to construct the bicyclic [3.3.0] scaffold bearing two vicinal quaternary carbon centers, a stereoselective γ-hydroxyl directed Michael addition to introduce the vinyl group at a bulky position, and a late-stage ring-closing metathesis reaction to form the cyclohexanone ring

    Influence of alkylation and esterification of 2-(4-methoxyphenoxy) propionic acid on sweet inhibition property and its manipulating mechanism

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    ABSTRACTThe current study applied 2-(4-methoxyphenoxy) propionic acid (HPMP) to prepare its alkylated and esterified derivatives and then investigated their corresponding sweetness inhibitory effect. The structure of these substituted derivatives were characterized by NMR and IR for ensuring their individual modification. The electronic tongue was used to predict the sweetness inhibitory effect of the derivatives, and a sweet prediction model was established via a three-dimensional measurement in term of sweetener type, sweetener and derivative concentrations. Furthermore, the interaction of sweetness inhibition with other taste properties was also studied. The current results indicated that, for alkylated derivatives, the sweetness inhibition rate of methyl-modified derivatives was higher than that of ethyl and propyl derivatives, and the inhibition rate of para-substituted derivatives was greater than that of ortho- and meta-positions. Interestingly, this study revealed that the esterification led to a minor sweetness inhibitory effect. Based on the current results, it is proposed that the ratio of hydrophobic and hydrophilic groups on the HPMP molecules plays the key role in regulating their corresponding sweetness inhibition via a binding capacity with the active site of sweet taste receptors

    Denoising Method for Seismic Co-Band Noise Based on a U-Net Network Combined with a Residual Dense Block

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    To address the problem of waveform distortion in the existing seismic signal denoising method when removing co-band noise, further improving the signal-to-noise ratio (SNR) of seismic signals and enhancing their quality, this paper designs a seismic co-band denoising model Atrous Residual Dense Block U-Net (ARDU), which uses a U-shaped convolutional neural network (U-Net) as a basic framework and combines atrous convolution and the residual dense block (RDB). In the ARDU model, atrous convolution is connected with residual dense blocks to form the feature extraction unit of the model encoder. Among them, the residual dense blocks can deepen the network’s depth and enhance the feature extraction ability of the network on the premise of mitigating the gradient-vanishing and gradient-exploding problem. Atrous convolution can enlarge receptive fields, reduce waveform distortion, and protect effective signals without increasing network parameters. To test the denoising performance of the ARDU model, the Stanford Global Seismic dataset was used to construct a training set and a test set and the model was trained and tested on it. The experimental results of the ARDU model for different types of seismic co-band noise showed that this model can effectively remove seismic co-band noise, protect effective signals, improve the SNR of seismic signals, and enhance the quality of seismic signals. To further verify the denoising effect of the model, this model was compared with the wavelet threshold denoising U-Net model and the denoising residual dense block (DnRDB) model, and the results showed that the ARDU model has the best SNR, r (correlation coefficient), and root-mean-square error (RMSE) and the least distortion of the seismic signal waveform

    A modified delta-shaped gastroduodenostomy in totally laparoscopic distal gastrectomy for gastric cancer: a safe and feasible technique.

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    The present study introduced a modified delta-shaped gastroduodenostomy (DSG) technique and assessed the safety, feasibility and clinical results of this procedure in patients undergoing totally laparoscopic distal gastrectomy (TLDG) for gastric cancer (GC).A total of 102 patients with distal GC undergoing TLDG with modified DSG between January 2013 and December 2013 were enrolled. A retrospective study was performed using a prospectively maintained comprehensive database to evaluate the results of the procedure. Univariate and multivariate analyses were performed to estimate the predictive factors for postoperative morbidity.The mean operation time was 150.6±30.2 min, the mean anastomosis time was 12.2±4.2 min, the mean blood loss was 48.2±33.2 ml, and the mean times to first flatus, fluid diet, soft diet and postoperative hospital stay were 3.8±1.3 days, 5.0±1.0 days, 7.4±2.1 days and 12.0±6.5 days, respectively. Two patients with minor anastomotic leakage after surgery were managed conservatively; no patient experienced any complications around the anastomosis, such as anastomotic stricture or anastomotic hemorrhage. Univariate analysis showed that age, gastric cancer with hemorrhage and cardiovascular disease combined were significant factors that affected postoperative morbidity (P<0.05). Multivariate analysis found that gastric cancer with hemorrhage was the independent risk factor for the postoperative morbidity (P = 0.042). At a median follow-up of 7 months, no patients had died or experienced recurrent or metastatic disease.The modified DSG was technically safe and feasible, with acceptable surgical outcomes, in patients undergoing TLDG for GC, and this procedure may be promising in these patients

    <i>p</i>,<i>p</i>′‑DDE Induces Gonadal Intersex in Japanese Medaka (<i>Oryzias latipes</i>) at Environmentally Relevant Concentrations: Comparison with <i>o</i>,<i>p</i>′‑DDT

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    Previous studies have reported high body burdens of dichlorodiphenyltrichloroethane (DDT) and its metabolites in wild fishes worldwide. This study evaluated the adverse effects of 1,1-dichloro-2,2-bis (<i>p</i>-chlorophenyl)-ethylene (<i>p</i>,<i>p</i>′-DDE) and <i>o</i>,<i>p</i>′<i>-</i>DDT on gonadal development and reproduction by exposing transgenic Japanese medaka (<i>Oryzias latipes</i>) from hatch for 100 days. While both <i>p</i>,<i>p</i>′-DDE and <i>o</i>,<i>p</i>′-DDT induced intersex in male medaka, the lowest observable effective concentration (LOEC) of <i>o</i>,<i>p</i>′-DDT was 57.7 ng/g ww, about 5-fold lower than that (272 ng/g ww) of <i>p</i>,<i>p</i>′-DDE. Since LOECs of both chemicals were comparable to the body concentrations in wild fish, DDT contamination would likely contribute to the occurrence of intersex observed in wild fish. Exposure to <i>o</i>,<i>p</i>′-DDT resulted in much higher expression of vitellogenin in liver of males than <i>p</i>,<i>p</i>′-DDE, accordant with the higher potency of <i>o</i>,<i>p</i>′-DDT than <i>p</i>,<i>p</i>′-DDE to induce intersex. This phenomenon could be partly explained by the significantly elevated levels of 17β-estradiol in plasma of males exposed to <i>o</i>,<i>p</i>′-DDT, in addition to its estrogenic activity via the estrogen receptor. Significantly lower fertilization (<i>p</i> = 0.006) and hatchability (<i>p</i> = 0.019) were observed in the 13 intersex males. This study for the first time demonstrated the induction of intersex and reproductive effects of <i>p</i>,<i>p</i>′-DDE and <i>o</i>,<i>p</i>′-DDT at environmentally relevant concentrations

    Terpenoids of Ganoderma lucidum reverse cognitive impairment through attenuating neurodegeneration via suppression of PI3K/AKT/mTOR expression in vivo model

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    This study investigated effects of triterpenoids derived from Ganoderma lucidum (GLT) on the ability to attenuate cognitive impairment and reduce oxidative stress and inflammation induced by D-galactose using an aged rats model. The data revealed that dietary GLT intervention improved the memory of aged rats in a water maze experiment. A reduction in inflammation was also achieved as GLT decreased the levels of MDA, AGEs, NO, TNF-α and AChE activity, and increased the activity of T-AOC, GSH-Px, T-SOD, CAT and IL-2 level in serum. The GLT intervention revised hepatocyte cellular arrangement and binucleation of the liver status, and even hippocampal neurons morphology. GLT upregulated the expression of FOXO4, SIRT1, and downregulated the expression of GFAP, iNOS, PI3K, AKT, mTOR and IL-6 with activation of PI3K/AKT/mTOR pathway. The current study highlights a promising dietary approach for prevention or alleviation of oxidative stress, inflammation and cognitive impairment induced by age-related conditions
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