The advent of the era of artificial intelligence provides technical support for cross-border e-commerce marketing to break the traditional competitive model and make efforts to build an online ...shopping platform that can meet international sellers’ and consumers’ transactions at any time around the world. This paper constructs a cross-border e-commerce marketing strategy optimization model based on deep reinforcement learning and convolutional neural network under artificial intelligence technology and explores the optimization method of the cross-border e-commerce marketing strategy by verifying the accuracy of the model and mining and analyzing the example data of Company A’s cross-border e-commerce platform. From the data, the accuracy of the deep convolutional neural network model is 99.47%, the proportion of beauty and beauty, mother and child care, and medical and health products in the product marketing strategy is 79.92%, 71.48%, and 59.93%, respectively, and the proportion of search traffic of the top three keywords in the search channel marketing is 42.69%, 31.23%, and 22.65%, respectively, and the ranking of the bottom The average traffic search of the seven types of keywords is less than 10%. This also shows that the optimization of a cross-border e-commerce marketing strategy based on the deep convolutional neural network can clearly analyze the data in the current marketing strategy, guide how to optimize the marketing strategy based on the data, and then improve the economic benefits of cross-border e-commerce enterprises. Applying a deep convolutional neural network model in a cross-border e-commerce marketing strategy also provides a direction for the new development field of artificial intelligence technology, which is beneficial to the further development of artificial intelligence technology.
The experimental solubility of LiCl–Li2SO4–MgCl2–MgSO4–H2O and KCl–K2SO4–MgCl2–MgSO4–H2O systems was measured at 288.15 K. The corresponding stable phase diagrams and water content diagrams were ...plotted by experimental results. Double salt was formed in both two systems. There are six phase fields, nine univariant solution curves and four invariant points in the phase diagram of LiCl–Li2SO4–MgCl2–MgSO4–H2O system. And the diagram of another system has seven invariant points and eight crystallization regions. By using multiple linear regression method, parameter ΨLi,Cl,SO4 and the solubility equilibrium constants of double salt KCl·MgSO4·3H2O were obtained by solubility data fitting at 288.15 K. The equilibrium solubility of salts in above systems at the same temperature was predicted with Pitzer's electrolyte solution model and mathematical calculation software. The results indicate that the predicted data are in correspondence with experiments.
•Phase equilibria of two systems Li(K)–Mg–Cl–SO4–H2O at 288.15 K were studied.•The solubility was determined by experiment and model prediction.•The two stable phase diagrams were obtained.•The calculated results are in good agreement with the experimental results.
Bacterial type VI secretion systems (T6SSs) inject toxic effectors into adjacent eukaryotic and prokaryotic cells. It is generally thought that this process requires physical contact between the two ...cells. Here, we provide evidence of contact-independent killing by a T6SS-secreted effector. We show that the pathogen Yersinia pseudotuberculosis uses a T6SS (T6SS-3) to secrete a nuclease effector that kills other bacteria in vitro and facilitates gut colonization in mice. The effector (Tce1) is a small protein that acts as a Ca
- and Mg
-dependent DNase, and its toxicity is inhibited by a cognate immunity protein, Tci1. As expected, T6SS-3 mediates canonical, contact-dependent killing by directly injecting Tce1 into adjacent cells. In addition, T6SS-3 also mediates killing of neighboring cells in the absence of cell-to-cell contact, by secreting Tce1 into the extracellular milieu. Efficient contact-independent entry of Tce1 into target cells requires proteins OmpF and BtuB in the outer membrane of target cells. The discovery of a contact-independent, long-range T6SS toxin delivery provides a new perspective for understanding the physiological roles of T6SS in competition. However, the mechanisms mediating contact-independent uptake of Tce1 by target cells remain unclear.
Purpose
COVID-19 has severely affected urban and rural tourism in China, which has been extensively reported in the newspapers. This paper aims to discuss the impact of COVID-19 on urban and rural ...tourism at each critical juncture of the COVID-19 pandemic, as well as the studies, measures and attitudes of various stakeholders toward urban and rural tourism and their future development.
Design/methodology/approach
This paper collects Chinese news reports as the research object and uses ROST Content Mining 6.0 and Gephi software to analyze and visualize the data for high-frequency words and analyzed the discourse of stakeholders within the newspaper text.
Findings
This study found that prior to February 20, 2020, the Chinese Government mainly focused on pandemic prevention. From February 21 to April 3 (before The Qingming Festival), resumption of work and production became the theme. From April 4 to May 1 (before May Day), a time-sharing reservation system was widely implemented and the differentiation between urban and rural tourism became more prominent. After May 1, rural tourism attracted greater attention.
Originality/value
This paper uses discourse analysis to understand the impact of COVID-19 on urban and rural tourism from the perspective of time nodes and the relationship between various stakeholders and predicts the development trends within urban and rural tourism. This paper enriches and expands tourism management knowledge in the face of major crises, providing valuable advice for managers and investors and makes suggestions for the development of urban and rural tourism.
COVID-19下中国的城乡旅游：恢复措施与旅游发展研究
目的
COVID-19已严重影响了中国的城市和乡村旅游业, 报纸上对此进行了广泛报道。本文旨在探讨在COVID-19大流行的每个关键时刻对城乡旅游的影响, 以及各种利益相关者对城乡旅游及其未来发展的观点, 措施和态度。
设计/方法
本文以中文新闻报道为研究对象, 利用ROST Content Mining 6.0和Gephi软件对高频词数据进行分析和可视化, 分析了报纸正文中利益相关者的话语。
结果
这项研究发现, 在2020年2月20日之前, 中国政府主要将重点放在疫情防控上。 2月21日至4月3日（清明节之前）, 复工复产成为主题。 从4月4日至5月1日（五一节之前）, 分时预约系统得到广泛实施, 城市和乡村旅游业的区别更加突出。 5月1日之后, 乡村旅游引起了更多关注。
创意/价值
本文通过话语分析从时间节点和各个利益相关者之间的关系的角度了解了COVID-19对城乡旅游业的影响, 并预测了城乡旅游业的发展趋势。 面对重大危机, 本文丰富和扩展了旅游管理知识, 为管理者和投资者提供了宝贵的建议, 并为城乡旅游业的发展提供了建议。
Turismo urbano y rural bajo COVID-19 en China Investigación sobre medidas de recuperación y desarrollo turístico
Propósito
COVID-19 ha afectado gravemente al turismo urbano y rural en China, que ha sido ampliamente informado en los periódicos. Este documento tiene como objetivo discutir el impacto de COVID-19 en el turismo urbano y rural en cada coyuntura crítica de la pandemia de COVID-19, así como los puntos de vista, las medidas y las actitudes de diversos interesados en relación con el turismo urbano y rural y su desarrollo futuro.
Diseño/metodología/enfoque
Este documento recopiló informes de noticias chinos como objeto de investigación y utilizó el software ROST Content Mining 6.0 y Gephi para analizar y visualizar los datos de palabras de alta frecuencia y analizó el discurso de los interesados dentro del texto del periódico.
Conclusiones
Este estudio encontró que antes del 20 de febrero de 2020, el gobierno chino se centró principalmente en la prevención de la pandemia en lugares pintorescos. Del 21 de febrero al 3 de abril (antes del Festival de Qingming), la reanudación del trabajo y la producción se convirtió en el tema. Desde el 4 de abril hasta el 1 de mayo (antes del Primero de Mayo), se implementó ampliamente un sistema de reserva de tiempo compartido y la diferenciación entre el turismo urbano y el rural se hizo más prominente. Después del 1 de mayo, el turismo rural atrajo mayor atención.
Originalidad/valor
En este documento, se utiliza el análisis del discurso para comprender el impacto de COVID-19 en el turismo urbano y rural desde la perspectiva de los nodos de tiempo y la relación entre los diversos interesados y se predice las tendencias de desarrollo dentro del turismo urbano y rural. Este trabajo enriquece y amplía el conocimiento de la gestión turística frente a las grandes crisis, brindando valiosos consejos a administradores e inversores, y hace sugerencias para el desarrollo del turismo urbano y rural.
Summary Background MicroRNAs (miRNAs) can be used as prognostic biomarkers in many types of cancer. We aimed to identify miRNAs that were prognostic in patients with nasopharyngeal carcinoma. Methods ...We retrospectively analysed miRNA expression profiles in 312 paraffin-embedded specimens of nasopharyngeal carcinoma from Sun Yat-sen University Cancer Center (Guangzhou, China) and 18 specimens of non-cancer nasopharyngitis. Using an 873 probe microarray, we assessed associations between miRNA signatures and clinical outcome in a randomly selected 156 samples (training set) and validated findings in the remaining 156 samples (internal validation set). We confirmed the miRNAs signature using quantitative RT-PCR analysis in 156 samples from a second randomisation of the 312 samples, and validated the miRNA signature in 153 samples from the West China Hospital of Sichuan University in Chengdu, China (independent set). We used the Kaplan-Meier method and log-rank tests to estimate correlations of the miRNA signature with disease-free survival (DFS), distant metastasis-free survival (DMFS), and overall survival. Findings 41 miRNAs were differentially expressed between nasopharyngeal carcinoma and non-cancer nasopharyngitis tissues. A signature of five miRNAs, each significantly associated with DFS, was identified in the training set. We calculated a risk score from the signature and classified patients as high risk or low risk. Compared with patients with low-risk scores, patients with high risk scores in the training set had shorter DFS (hazard ratio HR 2·73, 95% CI 1·46–5·11; p=0·0019), DMFS (3·48, 1·57–7·75; p=0·0020), and overall survival (2·48, 1·24–4·96; p=0·010). We noted equivalent findings in the internal validation set for DFS (2·47, 1·32–4·61; p=0·0052), DMFS (2·28, 1·09–4·80; p=0·030), and overall survival (2·87, 1·38–5·96; p=0·0051) and in the independent set for DFS (3·16, 1·65–6·04; p=0·0011), DMFS (2·39, 1·05–5·42; p=0·037), and overall survival (3·07, 1·34–7·01; p=0·0082). The five-miRNA signature was an independent prognostic factor. A combination of this signature and TNM stage had better prognostic value than did TNM stage alone in the training set (area under receiver operating characteristics 0·68 95% CI 0·60–0·76 vs 0·60 0·52–0·67; p=0·013), the internal validation set (0·70 0·61–0·78 vs 0·61 0·54–0·68; p=0·012), and the independent set (0·70 0·62–0·78 vs 0·63 0·56–0·69; p=0·032). Interpretation Identification of patients with the five-miRNA signature might add prognostic value to the TNM staging system and inform treatment decisions for patients at high risk of progression. Funding Science Foundation of Chinese Ministry of Health, National Natural Science Foundation of China, Pearl River Scholar Funded Scheme, Guangdong Key Scientific and Technological Innovation Program, Guangdong Natural Science Foundation, Fundamental Research Funds for the Central Universities.
Dielectric properties of poly(vinylidene fluoride) (PVDF) based nanocomposites filled with surface hydroxylated BaTiO3 (h-BT) nanoparticles were reported. The h-BT fillers were prepared from crude ...BaTiO3 (c-BT) in aqueous solution of H2O2. Results showed that the dielectric properties of the h-BT/PVDF nanocomposites had weaker temperature and frequency dependences than that of c-BT/PVDF nanocomposites. Meanwhile, the h-BT/PVDF composites showed lower loss tangent and higher dielectric strength. It is suggested that the strong interaction between h-BT fillers and PVDF matrix is the main reason for the improved dielectric properties.
Liver function has been suggested as a possible factor in the progression of Alzheimer's disease (AD) development. However, the association between liver function and cerebrospinal fluid (CSF) levels ...of AD biomarkers remains unclear. In this study, we analyzed the data from 1687 adults without dementia from the Chinese Alzheimer's Biomarker and LifestylE study to investigate differences in liver function between pathological and clinical AD groups, as defined by the 2018 National Institute on Aging-Alzheimer's Association Research Framework. We also examined the linear relationship between liver function, CSF AD biomarkers, and cognition using linear regression models. Furthermore, mediation analyses were applied to explore the potential mediation effects of AD pathological biomarkers on cognition. Our findings indicated that, with AD pathological and clinical progression, the concentrations of total protein (TP), globulin (GLO), and aspartate aminotransferase/alanine transaminase (ALT) increased, while albumin/globulin (A/G), adenosine deaminase, alpha-L-fucosidase, albumin, prealbumin, ALT, and glutamate dehydrogenase (GLDH) concentrations decreased. Furthermore, we also identified significant relationships between TP (β = -0.115, p
< 0.001), GLO (β = -0.184, p
< 0.001), and A/G (β = 0.182, p
< 0.001) and CSF β-amyloid
(Aβ
) (and its related CSF AD biomarkers). Moreover, after 10 000 bootstrapped iterations, we identified a potential mechanism by which TP and GLDH may affect cognition by mediating CSF AD biomarkers, with mediation effect sizes ranging from 3.91% to 16.44%. Overall, our results suggested that abnormal liver function might be involved in the clinical and pathological progression of AD. Amyloid and tau pathologies also might partially mediate the relationship between liver function and cognition. Future research is needed to fully understand the underlying mechanisms and causality to develop an approach to AD prevention and treatment approach.
Clove essential oil (CEO) was immobilized in mesoporous silica nanoparticles (MSN) (0, 1, 2, and 3 wt%) and incorporated into poly(lactic acid) (PLA) matrix via a casting method. The functional ...properties including mechanical property, thermal property, antimicrobial property, and CEO release behavior of the PLA nanocomposite film were investigated. The compatibility of CEO-loading MSN with PLA was verified by scanning electron microscopy analysis. The tensile strength, tensile module, and glass transition temperature of the MSN/CEO/PLA composite film was improved with the increase in MSN content. The release study indicated that the MSN/CEO/PLA composite films exhibited sustained release profile of CEO. The MSN/CEO/PLA films demonstrated efficient antimicrobial activity. The results indicated that CEO immobilized MSN incorporated PLA nanocomposite film showed promising features for active food packaging material.
Recent findings have reported that human serum microRNAs (miRNAs) can be used as prognostic biomarkers in various cancers. We aimed to explore the prognostic value of serum miRNAs in nasopharyngeal ...carcinoma (NPC) patients. The level of serum miRNA was retrospectively analyzed in 512 NPC patients recruited between January 2001 and December 2006. In the discovery stage, a microarray followed by reverse transcription‐quantitative polymerase chain reaction was used to identify differentially altered miRNAs in eight patients with shorter survival and eight patients with longer survival who were well matched by age, sex and clinical stage. The identified serum miRNAs were then validated in all 512 samples, which were randomly divided into a training set and a validation set. Four serum miRNAs (miR‐22, miR‐572, miR‐638 and miR‐1234) were found to be differentially altered and were used to construct a miRNA signature. Risk scores were calculated to classify the patients into high‐ or low‐risk groups. Patients with high‐risk scores had poorer overall survival hazard ratio (HR), 2.54; 95% confidence interval (CI), 1.57–4.12; p < 0.001 and distant metastasis‐free survival (HR, 3.28; 95% CI, 1.82–5.94; p < 0.001) than those with low‐risk scores in the training set; these results were confirmed in the validation and combined sets. The miRNA signature and TNM stage were independent prognostic factors. The combination of the miRNA signature and TNM stage had a better prognostic value than the TNM stage or miRNA signature alone. The four‐serum miRNA signature may add prognostic value to the TNM staging system and provide information for personalized therapy in NPC.
What's new?
Short non‐coding RNA sequences, or microRNAs, that circulate in serum are easily accessible, promising biomarkers for incorporation into the tumor‐node‐metastasis (TNM) staging system. This study shows that a four‐miRNA signature is able to predict survival in nasopharyngeal carcinoma, serving as an independent prognostic factor. When combined with TNM staging, the miRNA signature boosted the overall prognostic power, improving it over either approach alone. The results also suggest that serum miRNAs may play an important role in nasopharyngeal carcinoma development and progression, in addition to being potential prognostic biomarkers.
Bubble dynamics near different boundaries have always been a hot topic in ocean engineering and many other fields. In the present study, we investigate the dynamics of high-pressure pulsating bubbles ...near a concave surface via experimental and numerical methods. Pulsating cavitation bubbles are generated by the electric discharge technique, and the violent expansion, contraction, and jet formation are observed through high-speed photography. Additionally, a multi-vortex ring model implemented in the boundary integral method is established to simulate the bubble motion near a curved surface. The precise non-spherical bubble shapes during bubble pulsation and detailed information on the jet velocity and wall pressure are obtained. The numerical results are found to be in good agreement with the experimental results, indicating the validity of the numerical model. Finally, a quantitative study is provided on the influence of two parameters: the distance parameter γ=L/Rm (L is the distance between the initial bubble center and the lowest point of the concave surface and Rm is the maximum bubble radius) and the concave curvature ξ=Rm/Rs (Rs is the radius of concave boundary).
•Bubble dynamics near a concave surface were experimentally and numerically studied.•An extreme case of a bubble in contact with a concave boundary can be simulated.•The effect of the distance parameter on bubble dynamics is discussed.•The effect of concave curvature on bubble dynamics is unveiled.
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