1,006 research outputs found

    A Branch and Bound Algorithm for the Exact Solution of the Problem of EMU Circulation Scheduling in Railway Network

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    This paper is concerned with the scheduling of Electrical Multiple Units (EMUs) under the condition of their utilization on one sector or within several interacting sectors. Based on the introduction of the train connection graph which describes the possible connection relationship between trains, the integer programming model of EMU circulation planning is constructed. In order to analyzing the resolution of the model, a heuristic which shares the characteristics with the existing methods is introduced first. This method consists of two stages: one is a greedy strategy to construct a feasible circulation plan fragment, and another is to apply a stochastic disturbance to it to generate a whole feasible solution or get a new feasible solution. Then, an exact branch and bound method which is based on graph designing is proposed. Due to the complexity, the lower bound is computed through a polynomial approximation algorithm which is a modification from the one solving the degree constraint minimum 1-tree problem. Then, a branching strategy is designed to cope with the maintenance constraints. Finally, we report extensive computational results on a railway corridor in which the sectors possess the basic feature of railway networks

    Polarization-based probabilistic discriminative model for quantitative characterization of cancer cells

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    We propose a polarization-based probabilistic discriminative model for deriving a set of new sigmoid-transformed polarimetry feature parameters, which not only enables accurate and quantitative characterization of cancer cells at pixel level, but also accomplish the task with a simple and stable model. By taking advantages of polarization imaging techniques, these parameters enable a low-magnification and wide-field imaging system to separate the types of cells into more specific categories that previously were distinctive under high magnification. Instead of blindly choosing the model, the L0 regularization method is used to obtain the simplified and stable polarimetry feature parameter. We demonstrate the model viability by using the pathological tissues of breast cancer and liver cancer, in each of which there are two derived parameters that can characterize the cells and cancer cells respectively with satisfactory accuracy and sensitivity. The stability of the final model opens the possibility for physical interpretation and analysis. This technique may bypass the typically labor-intensive and subjective tumor evaluating system, and could be used as a blueprint for an objective and automated procedure for cancer cell screening

    The histone H3K9M mutation synergizes with H3K14 ubiquitylation to selectively sequester histone H3K9 methyltransferase Clr4 at heterochromatin

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    International audienceOncogenic histone lysine-to-methionine mutations block the methylation of their corresponding lysine residues on wild-type histones. One attractive model is that these mutations sequester histone methyltransferases, but genome-wide studies show that mutant histones and histone methyltransferases often do not colocalize. Using chromatin immunoprecipitation sequencing (ChIP-seq), here, we show that, in fission yeast, even though H3K9M-containing nucleosomes are broadly distributed across the genome, the histone H3K9 methyltransferase Clr4 is mainly sequestered at pericentric repeats. This selective sequestration of Clr4 depends not only on H3K9M but also on H3K14 ubiquitylation (H3K14ub), a modification deposited by a Clr4-associated E3 ubiquitin ligase complex. In vitro, H3K14ub synergizes with H3K9M to interact with Clr4 and potentiates the inhibitory effects of H3K9M on Clr4 enzymatic activity. Moreover, binding kinetics show that H3K14ub overcomes the Clr4 aversion to H3K9M and reduces its dissociation. The selective sequestration model reconciles previous discrepancies and demonstrates the importance of protein-interaction kinetics in regulating biological processes

    The Protective Effect of Propofol Against Ischemia–Reperfusion Injury in the Interlobar Arteries: Reduction of Abnormal Cx43 Expression as a Possible Mechanism

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    Background/Aims: This experimental study aims to observe whether the protective effect of propofol against renal ischemia–reperfusion injury (IRI) in the rat interlobar artery occurs through altered expression of the gap junction protein connexin 43 (Cx43). Methods: This study randomly divided male Sprague Dawley (SD) rats into an untreated control group, a sham-operated control group (sham group), an ischemia–reperfusion group (IR group), a propofol group (propofol+IR group) and a fat emulsion group (Intralipid group). The ischemia/reperfusion model was prepared through resection of the right kidney and noninvasive arterial occlusion of the left kidney. Forty-five minutes after renal ischemia–reperfusion, an automatic biochemical analyzer was employed to measure blood urea nitrogen (BUN) and serum creatinine (SCr); changes in renal tissue pathology were observed using hematoxylin and eosin (HE) staining, and the vasomotor activity of the interlobar artery was detected using a pressure mechanogram technique. The protein expression of Cx43 in renal artery cross-sections was determined through western blotting. Results: The experimental study confirmed that the BUN and SCr of rats markedly increased after ischemia–reperfusion injury; additionally, we observed some coagulation necrosis and shedding of cells, some solidification of nuclear chromatin, degeneration of cytoplasmic vacuoles, high renal interstitial vascular congestion and obvious inflammatory cell infiltration, characterized by focal hemorrhages. Furthermore, the contraction activity of the renal interlobar artery greatly decreased, and the tension of the arteries in the renal lobe increased remarkably. After the gap junction blocking agents 2-APB and Gap27 were applied, the systolic velocity of blood vessels and the vascular contraction rate both decreased. In addition, the expression of Cx43 in kidney tissues increased markedly. The damage was more severe after 24 h of ischemic reperfusion than after only 4 h. However, after pretreatment with propofol, regardless of whether ischemia–reperfusion was applied for 4 h or 24 h, the previously increased expression of Cx43 decreased obviously, and all forms of renal damage were reversed. Conclusion: Our research suggests new ways for propofol to relieve ischemia–reperfusion injury by decreasing the abnormal expression of the gap junction protein Cx43. This study reveals a novel mechanism for the action of propofol against IRI, and we hope this finding will lead to new treatments for IRI

    Corrigendum to: The TianQin project: current progress on science and technology

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    In the originally published version, this manuscript included an error related to indicating the corresponding author within the author list. This has now been corrected online to reflect the fact that author Jun Luo is the corresponding author of the article

    Seizing the window of opportunity to mitigate the impact of climate change on the health of Chinese residents

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    The health threats posed by climate change in China are increasing rapidly. Each province faces different health risks. Without a timely and adequate response, climate change will impact lives and livelihoods at an accelerated rate and even prevent the achievement of the Healthy and Beautiful China initiatives. The 2021 China Report of the Lancet Countdown on Health and Climate Change is the first annual update of China’s Report of the Lancet Countdown. It comprehensively assesses the impact of climate change on the health of Chinese households and the measures China has taken. Invited by the Lancet committee, Tsinghua University led the writing of the report and cooperated with 25 relevant institutions in and outside of China. The report includes 25 indicators within five major areas (climate change impacts, exposures, and vulnerability; adaptation, planning, and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement) and a policy brief. This 2021 China policy brief contains the most urgent and relevant indicators focusing on provincial data: The increasing health risks of climate change in China; mixed progress in responding to climate change. In 2020, the heatwave exposures per person in China increased by 4.51 d compared with the 1986–2005 average, resulting in an estimated 92% increase in heatwave-related deaths. The resulting economic cost of the estimated 14500 heatwave-related deaths in 2020 is US$176 million. Increased temperatures also caused a potential 31.5 billion h in lost work time in 2020, which is equivalent to 1.3% of the work hours of the total national workforce, with resulting economic losses estimated at 1.4% of China’s annual gross domestic product. For adaptation efforts, there has been steady progress in local adaptation planning and assessment in 2020, urban green space growth in 2020, and health emergency management in 2019. 12 of 30 provinces reported that they have completed, or were developing, provincial health adaptation plans. Urban green space, which is an important heat adaptation measure, has increased in 18 of 31 provinces in the past decade, and the capacity of China’s health emergency management increased in almost all provinces from 2018 to 2019. As a result of China’s persistent efforts to clean its energy structure and control air pollution, the premature deaths due to exposure to ambient particulate matter of 2.5 μm or less (PM2.5) and the resulting costs continue to decline. However, 98% of China’s cities still have annual average PM2.5 concentrations that are more than the WHO guideline standard of 10 μg/m3. It provides policymakers and the public with up-to-date information on China’s response to climate change and improvements in health outcomes and makes the following policy recommendations. (1) Promote systematic thinking in the related departments and strengthen multi-departmental cooperation. Sectors related to climate and development in China should incorporate health perspectives into their policymaking and actions, demonstrating WHO’s and President Xi Jinping’s so-called health-in-all-policies principle. (2) Include clear goals and timelines for climate-related health impact assessments and health adaptation plans at both the national and the regional levels in the National Climate Change Adaptation Strategy for 2035. (3) Strengthen China’s climate mitigation actions and ensure that health is included in China’s pathway to carbon neutrality. By promoting investments in zero-carbon technologies and reducing fossil fuel subsidies, the current rebounding trend in carbon emissions will be reversed and lead to a healthy, low-carbon future. (4) Increase awareness of the linkages between climate change and health at all levels. Health professionals, the academic community, and traditional and new media should raise the awareness of the public and policymakers on the important linkages between climate change and health.</p

    Review of advanced road materials, structures, equipment, and detection technologies

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    As a vital and integral component of transportation infrastructure, pavement has a direct and tangible impact on socio-economic sustainability. In recent years, an influx of groundbreaking and state-of-the-art materials, structures, equipment, and detection technologies related to road engineering have continually and progressively emerged, reshaping the landscape of pavement systems. There is a pressing and growing need for a timely summarization of the current research status and a clear identification of future research directions in these advanced and evolving technologies. Therefore, Journal of Road Engineering has undertaken the significant initiative of introducing a comprehensive review paper with the overarching theme of “advanced road materials, structures, equipment, and detection technologies”. This extensive and insightful review meticulously gathers and synthesizes research findings from 39 distinguished scholars, all of whom are affiliated with 19 renowned universities or research institutions specializing in the diverse and multidimensional field of highway engineering. It covers the current state and anticipates future development directions in the four major and interconnected domains of road engineering: advanced road materials, advanced road structures and performance evaluation, advanced road construction equipment and technology, and advanced road detection and assessment technologies

    Search for hidden-charm tetraquark with strangeness in e+eK+DsD0+c.c.e^{+}e^{-}\rightarrow K^+ D_{s}^{*-} D^{*0}+c.c.

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    We report a search for a heavier partner of the recently observed Zcs(3985)Z_{cs}(3985)^{-} state, denoted as ZcsZ_{cs}^{\prime -}, in the process e+eK+DsD0+c.c.e^{+} e^{-}\rightarrow K^{+}D_{s}^{*-}D^{* 0}+c.c., based on e+ee^+e^- collision data collected at the center-of-mass energies of s=4.661\sqrt{s}=4.661, 4.682 and 4.699 GeV with the BESIII detector. The ZcsZ_{cs}^{\prime -} is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark. A partial-reconstruction technique is used to isolate K+K^+ recoil-mass spectra, which are probed for a potential contribution from ZcsDsD0Z_{cs}^{\prime -}\to D_{s}^{*-}D^{* 0} (c.c.c.c.). We find an excess of ZcsDsD0Z_{cs}^{\prime -}\rightarrow D_{s}^{*-}D^{*0} (c.c.c.c.) candidates with a significance of 2.9σ2.9\sigma, after considering systematic uncertainties, at a mass of (4123.5±0.7stat.±1.1syst.)MeV/c2(4123.5 \pm 0.7_{\mathrm{stat.}} \pm 1.1_{\mathrm{syst.}}) \mathrm{MeV}/c^{2}. As the data set is limited in size, the upper limits are evaluated at the 90% confidence level on the product of the Born cross section and the branching fraction of ZcsDsD0Z_{cs}^{\prime-}\rightarrow D_{s}^{*-}D^{* 0}, σBornB\sigma^{\rm Born}\cdot\mathcal{B} at the three energy points, under different assumptions of the ZcsZ_{cs}^{\prime -} mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV. Under various mass and width assumptions, the upper limits of σBornB\sigma^{\rm Born}\cdot\mathcal{B} are found to lie in the range of 262\sim6, 373\sim7 and 363\sim6 pb at s=4.661\sqrt{s}=4.661, 4.682 and 4.699 GeV, respectively. The larger data samples that will be collected in the coming years will allow a clearer picture to emerge concerning the existence and nature of the ZcsZ_{cs}^{\prime -} state.Comment: 17 pages, 7 figure
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