Study on Fatigue Characteristics of Concrete Sleepers with Porous Basalt as the Aggregate

Due to the shortage of local materials, porous basalt was used as the coarse aggregate in the prefabrication of sleepers for the Mombasa-Nairobi Railway in Kenya. To study their fatigue characteristics, the sleepers were measured under fatigue loading for their local strain, overall deformation and crack initiation. The methods used include the traditional strain measurement, the sleeper deflection measurement and the 3D optical strain measurement. To be more specific, the traditional strain measurement method was employed to compare the strain-load relation of the sleepers under different cyclic loading times. Deflection variations of the sleepers were taken into consideration to analyze sleeper local defects and the variation law of the constitutive relation for concrete. And the 3D optical non-contact strain measurement method was adopted to monitor the sleeper crack initiation and growth process under fatigue loading and analyze the crack growth law

Marketing Budget Allocation with Offline Constrained Deep Reinforcement Learning

We study the budget allocation problem in online marketing campaigns that utilize previously collected offline data. We first discuss the long-term effect of optimizing marketing budget allocation decisions in the offline setting. To overcome the challenge, we propose a novel game-theoretic offline value-based reinforcement learning method using mixed policies. The proposed method reduces the need to store infinitely many policies in previous methods to only constantly many policies, which achieves nearly optimal policy efficiency, making it practical and favorable for industrial usage. We further show that this method is guaranteed to converge to the optimal policy, which cannot be achieved by previous value-based reinforcement learning methods for marketing budget allocation. Our experiments on a large-scale marketing campaign with tens-of-millions users and more than one billion budget verify the theoretical results and show that the proposed method outperforms various baseline methods. The proposed method has been successfully deployed to serve all the traffic of this marketing campaign.Comment: WSDM 23, Best Paper Candidat

Identification of molecular subtypes, risk signature, and immune landscape mediated by necroptosis-related genes in non-small cell lung cancer

BackgroundNon-small cell lung cancer (NSCLC) is a highly heterogeneous malignancy with an extremely high mortality rate. Necroptosis is a programmed cell death mode mediated by three major mediators, RIPK1, RIPK3, and MLKL, and has been shown to play a role in various cancers. To date, the effect of necroptosis on NSCLC remains unclear.MethodsIn The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, we downloaded transcriptomes of lung adenocarcinoma (LUAD) patients and their corresponding clinicopathological parameters. We performed multi-omics analysis using consensus clustering based on the expression levels of 40 necroptosis-related genes. We constructed prognostic risk models and used the receiver operating characteristic (ROC) curves, nomograms, and survival analysis to evaluate prognostic models.ResultsWith the use of consensus clustering analysis, two distinct subtypes of necroptosis were identified based on different mRNA expression levels, and cluster B was found to have a better survival advantage. Correlation results showed that necroptosis was significantly linked with clinical features, overall survival (OS) rate, and immune infiltration. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis confirmed that these differential genes were valuable in various cellular and biological functions and were significantly enriched in various pathways such as the P53 signaling pathway and cell cycle. We further identified three genomic subtypes and found that gene cluster B patients had better prognostic value. Multivariate Cox analysis identified the 14 best prognostic genes for constructing prognostic risk models. The high-risk group was found to have a poor prognosis. The construction of nomograms and ROC curves showed stable validity in prognostic prediction. There were also significant differences in tumor immune microenvironment, tumor mutational burden (TMB), and drug sensitivity between the two risk groups. The results demonstrate that the 14 genes constructed in this prognostic risk model were used as tumor prognostic biomarkers to guide immunotherapy and chemotherapy. Finally, we used qRT-PCR to validate the genes involved in the signature.ConclusionThis study promotes our new understanding of necroptosis in the tumor microenvironment of NSCLC, mines prognostic biomarkers, and provides a potential value for guiding immunotherapy and chemotherapy

Detection and imaging of the free radical DNA in cells—Site-specific radical formation induced by Fenton chemistry and its repair in cellular DNA as seen by electron spin resonance, immuno-spin trapping and confocal microscopy

Oxidative stress-related damage to the DNA macromolecule produces lesions that are implicated in various diseases. To understand damage to DNA, it is important to study the free radical reactions causing the damage. Measurement of DNA damage has been a matter of debate as most of the available methods measure the end product of a sequence of events and provide limited information on the initial free radical formation. We report a measurement of free radical damage in DNA induced by a Cu(II)-H2O2 oxidizing system using immuno-spin trapping supplemented with electron paramagnetic resonance. In this investigation, the short-lived radical generated is trapped by the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) immediately upon formation. The DMPO adduct formed is initially electron paramagnetic resonance active, but is subsequently oxidized to the stable nitrone adduct, which can be detected and visualized by immuno-spin trapping and has the potential to be further characterized by other analytical techniques. The radical was found to be located on the 20-deoxyadenosine (dAdo) moiety of DNA. The nitrone adduct was repaired on a time scale consistent with DNA repair. In vivo experiments for the purpose of detecting DMPO–DNA nitrone adducts should be conducted over a range of time in order to avoid missing adducts due to the repair processes

Fault Diagnosis of Internal Combustion Engine Valve Clearance Using the Impact Commencement Detection Method

Internal combustion engines (ICEs) are widely used in many important fields. The valve train clearance of an ICE usually exceeds the normal value due to wear or faulty adjustment. This work aims at diagnosing the valve clearance fault based on the vibration signals measured on the engine cylinder heads. The non-stationarity of the ICE operating condition makes it difficult to obtain the nominal baseline, which is always an awkward problem for fault diagnosis. This paper overcomes the problem by inspecting the timing of valve closing impacts, of which the referenced baseline can be obtained by referencing design parameters rather than extraction during healthy conditions. To accurately detect the timing of valve closing impact from vibration signals, we carry out a new method to detect and extract the commencement of the impacts. The results of experiments conducted on a twelve-cylinder ICE test rig show that the approach is capable of extracting the commencement of valve closing impact accurately and using only one feature can give a superior monitoring of valve clearance. With the help of this technique, the valve clearance fault becomes detectable even without the comparison to the baseline, and the changing trend of the clearance could be trackable

Effects of Variety, Season, and Region on Theaflavins Content of Fermented Chinese Congou Black Tea

The effects of variety, region, and season on the theaflavins content of fermented Congou black tea were determined. Fresh tea leaves from 5 varieties, 3 tea-growing regions, and 3 harvesting seasons were treated by withering, rolling, fermenting, and drying. Contents of theaflavins, polyphenol oxidase (PPO), peroxidase (POD), and individual catechins in each treatment process were determined. The results showed that the varieties of Yinghong 9 and Hongyan 12 produced high concentrations of theaflavin, as much as 0.5% and 0.6%, respectively. The production capacity of theaflavin in different regions had the trend of Yingde > Changsha > Hangzhou. Fresh leaves plucked in spring season produced the strongest theaflavins. In tea leaves, high ratio of PPO to POD activity and high contents of certain individual catechins lead to high yield of theaflavin production during the whole process