228 research outputs found

    Thermostat-assisted continuously-tempered Hamiltonian Monte Carlo for Bayesian learning

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    We propose a new sampling method, the thermostat-assisted continuously-tempered Hamiltonian Monte Carlo, for Bayesian learning on large datasets and multimodal distributions. It simulates the Nos\'e-Hoover dynamics of a continuously-tempered Hamiltonian system built on the distribution of interest. A significant advantage of this method is that it is not only able to efficiently draw representative i.i.d. samples when the distribution contains multiple isolated modes, but capable of adaptively neutralising the noise arising from mini-batches and maintaining accurate sampling. While the properties of this method have been studied using synthetic distributions, experiments on three real datasets also demonstrated the gain of performance over several strong baselines with various types of neural networks plunged in

    Brand User Attention Model Based on Online Text Reviews: An Empirical Study of New Energy Automobile Brands

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    Accurately grasping the rules of user behavior and market changes and timely adjusting decisions and strategies are the ways for brand development and innovation. In this paper, we proposed a brand user attention model based on online text review analysis. First of all, we collected and preprocessed the user comment text from the online forum. Secondly, through the LDA topic model and LDAvis visual analysis, the potential topics of user reviews were extracted, and a multi-dimensional feature analysis model was constructed to reveal the users\u27 attention features of brand products. Finally, took the new energy automobile brands as an example, the users\u27 attention features for the different new energy automobile brands were explored and the empirical study was carried out. This study found that the brand user attention model based on online text analysis can effectively extract the characteristics that brand users care about, obtain valuable business insight, and provide support for managers\u27 decision-making

    Intelligent Block Assignment for Blockchain Based Wireless IoT Systems

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    In legacy blockchain based systems, each involved node has to store a complete blockchain to ensure the system security without any central authoritative controller. However, it is usually impossible for a wireless IoT node to store a complete blockchain, especially for those simple sensor nodes without sufficient storage and computing resources. In this paper, we propose a block assignment scheme for blockchain based wireless IoT systems with aim to tackle the blockchain storage problem. Specifically, we propose to maintain a complete blockchain by a set of IoT nodes in a collaborative way on the premise of ensuring that each node can check every transaction. On the other hand, we should save the storage space of IoT nodes to the greatest extent for saving more blocks so as to maximize the lifetime of IoT nodes. We formulate this optimal block assignment problem as a 0-1 mixed integer-programming problem. We propose to incorporate Chaotic optimized algorithm into Genetic algorithm to provide an efficient near-optimal solution. Compared with the brute-force and conventional Genetic algorithms, our proposed algorithm can achieve the minimum storage occupancy to store blocks. Meanwhile, the proposed algorithm has the lowest computational complexity

    Microfluidic production of porous chitosan/silica hybrid microspheres and its Cu(II) adsorption performance

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    AbstractWaste water with heavy metal ions has been of great concern because of its increased discharge, toxic and some other bad effects on human beings or the environment. In this article, monodispersed chitosan/silica hybrid microspheres with porous structure and large specific surface area were successfully prepared by using microfluidic technology and they have advantages in mechanical property and adsorption of heavy metal ions such as Cu(II). In the optimum condition, porous chitosan/silica hybrid microspheres with 1.0wt.% TEOS in the dispersed phase and pre-solidified for 3h have enhanced mechanical intensity, faster adsorption kinetic and larger equilibrium adsorption amount of Cu(II) compared to the porous chitosan microspheres. The mechanical intensity and adsorption rate of the porous hybrid microspheres were 1.5 times and two times of porous chitosan microspheres, respectively. Meantime, the adsorption capacity was increased by 25%. The porous hybrid microspheres have good potentials in the applications of removing heavy metal ions from waste water

    Study on the Imprinting Status of Insulin-Like Growth Factor II (IGF-II) Gene in Villus during 6–10 Gestational Weeks

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    Objective. To compare the difference of imprinting status of insulin-like growth factor II (IGF-II) gene in villus between normal embryo development group and abnormal embryo development group and to investigate the relationship between karyotype and the imprinting status of IGF-II gene. Methods. A total of 85 pregnant women with singleton pregnancy were divided into two groups: one with abnormal embryo development (n = 38) and the other with normal embryo development (n = 47). Apa I polymorphism of IGF-II gene in chorionic villus was assayed with reverse transcriptase polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP). The relationship between chromosomal abnormal karyotype and IGF-II gene imprinting status was analyzed by primary cell culture and G-banding chromosomal karyotype analysis. Results. IGF-II imprinting loss rate was higher in the abnormal embryo development group than the normal embryo development group (44.7% versus 31.6%), but without significant difference (P > .05). The percentage of abnormal chromosomes of chorionic villus in the abnormal embryo development group was 42.5%, in which IGF-II imprinting loss rate reached 64.7%. No abnormal karyotypes were found in the normal embryo development group. However, there was significant difference in IGF-II imprinting loss rate between two groups (P > .05). Conclusion. During weeks 6–10 of gestation, abnormal embryonic development is correlated with chromosomal abnormalities. The imprinting status of IGF-II gene played important roles in embryonic development, and imprinting loss might be related to chromosomal abnormalities

    A Mathematical Model for Pathogen Cross-Contamination Dynamics During Produce Wash

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    One of the main challenges for the fresh-food produce industry is to ensure that the produce is free from harmful pathogens. A potential area of risk is due to cross-contamination in a sanitizing chlorine wash-cycle, where the same water is used to wash contaminated as well as non-contaminated produce. However, this is also an area where effective intervention strategies are possible, provided we have a good understanding of the mechanism of cross-contamination. Based on recent experimental work by Luo, Y. et al. A pilot plant scale evaluation of a new process aid for enhancing chlorine efficacy against pathogen survival and cross-contamination during produce wash, International Journal of Food Microbiology, 158 (2012), 133–139, we have built mathematical models that allow us to quantify the amount of cross-contamination of Escherichia coli O157:H7 from spinach to lettuce, and assessed the efficacy of the associated wash-cycle protocols

    Efficacy and safety of acupuncture for depression: A systematic review and meta-analysis

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    Acupuncture is widely accepted as a therapeutic option for managing depression. However, evidence from clinical trials remains controversial. This review aims to synthesize the best available evidence on the efficacy and safety of acupuncture in managing depression. The review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Five databases and the relevant trial registries were searched from the inception to October 2021. Randomized clinical trials of acupuncture for managing depression, published in English, were selected for inclusion. The quality of included studies was assessed using the Cochrane risk of bias tool. Netmeta and dmetar of R packages were used to conduct a network meta-analysis. Twenty-two trials with 2391 participants were eligible and included in the analysis. This review found evidence that electroacupuncture (EA) plus antidepressant achieved superior outcomes compared with the waitlist (standardized mean difference = −8.86, 95% confidence interval: −14.78 to −2.93). The treatment ranking of different interventions in improving depression symptoms indicated that EA plus antidepressant with a probability of 0.8294, followed by manual acupuncture (MA) plus antidepressant (0.6470) and MA (0.5232). Acupuncture, either in isolation or as an adjunct to pharmacological treatment, has clinical benefits and can be considered a safe option for managing depression

    Inherently Fluorescent Peanut-Shaped Polymersomes for Active Cargo Transportation

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    Nanomotors have been extensively explored for various applications in nanomedicine, especially in cargo transportation. Motile properties enable them to deliver pharmaceutical ingredients more efficiently to the targeted site. However, it still remains a challenge to design motor systems that are therapeutically active and can also be effectively traced when taken up by cells. Here, we designed a nanomotor with integrated fluorescence and therapeutic potential based on biodegradable polymersomes equipped with aggregation-induced emission (AIE) agents. The AIE segments provided the polymersomes with autofluorescence, facilitating the visualization of cell uptake. Furthermore, the membrane structure enabled the reshaping of the AIE polymersomes into asymmetric, peanut-shaped polymersomes. Upon laser irradiation, these peanut polymersomes not only displayed fluorescence, but also produced reactive oxygen species (ROS). Because of their specific shape, the ROS gradient induced motility in these particles. As ROS is also used for cancer cell treatment, the peanut polymersomes not only acted as delivery vehicles but also as therapeutic agents. As an integrated platform, these peanut polymersomes therefore represent an interesting delivery system with biomedical potential.</p

    Inherently Fluorescent Peanut-Shaped Polymersomes for Active Cargo Transportation

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    Nanomotors have been extensively explored for various applications in nanomedicine, especially in cargo transportation. Motile properties enable them to deliver pharmaceutical ingredients more efficiently to the targeted site. However, it still remains a challenge to design motor systems that are therapeutically active and can also be effectively traced when taken up by cells. Here, we designed a nanomotor with integrated fluorescence and therapeutic potential based on biodegradable polymersomes equipped with aggregation-induced emission (AIE) agents. The AIE segments provided the polymersomes with autofluorescence, facilitating the visualization of cell uptake. Furthermore, the membrane structure enabled the reshaping of the AIE polymersomes into asymmetric, peanut-shaped polymersomes. Upon laser irradiation, these peanut polymersomes not only displayed fluorescence, but also produced reactive oxygen species (ROS). Because of their specific shape, the ROS gradient induced motility in these particles. As ROS is also used for cancer cell treatment, the peanut polymersomes not only acted as delivery vehicles but also as therapeutic agents. As an integrated platform, these peanut polymersomes therefore represent an interesting delivery system with biomedical potential.</p

    Study and Discussion on Preparation of Hemihydrate Gypsum by Salt Solution Method

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    This is an article in the field of mineral materials. The utilization of desulfurized gypsum (FGD) to prepare more widely used hemihydrate gypsum plays a very important role in the resource utilization of industrial by-product gypsum. It can not only avoid the large-scale exploitation of natural gypsum, but also realize the resource utilization of desulfurized gypsum. In the process of converting FGD gypsum into hemihydrate gypsum, appropriate concentration of additive and sodium chloride were used as the reaction solution, and the process was heated and stirred under normal pressure. The effects of sodium chloride concentration, additive concentration, solid-liquid ratio, rotation speed and reaction temperature on the phase conversion time and crystal size of dihydrate to hemihydrate gypsum were studied. The increase of additive and sodium chloride concentration not only sped up the phase conversion process but also had a certain inhibitory effect on the average length and average aspect ratio of hemihydrate gypsum crystals. Higher or lower rotation speed hindered the nucleation and growth of hemihydrate gypsum crystals and affected the collision frequency of Ca2+ and SO42- in the NaCl added solution, thus delaying the formation of hemihydrate gypsum. Decreasing the solid-liquid ratio and increasing the temperature had a certain promoting effect on the phase conversion process. At a lower temperature, due to the insufficient driving force of the phase conversion process, it was difficult to transform FGD gypsum into hemihydrate gypsum. The optimal process conditions for preparing hemihydrate gypsum from FGD gypsum were determined as follows: sodium chloride concentration 10%, additive concentration 10%, solid-liquid ratio 1∶5, rotating speed 300 r/min, reaction temperature 100 ℃. Under the best process conditions, the reaction could be completed in 60 min. The average length of the prepared hemihydrate gypsum crystals was as high as 127 μm, and the average aspect ratio was as high as 19. At the same time, the relationship between the activity of water molecules in the solution, the degree of supersaturation and the reaction temperature was studied, and it was determined that the phase conversion process was determined by the temperature and the degree of supersaturation
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