Text classification is the task of assigning predefined categories to natural language documents, and it can provide conceptual views of document collections. The Naïve Bayes (NB) classifier is a ...family of simple probabilistic classifiers based on a common assumption that all features are independent of each other, given the category variable, and it is often used as the baseline in text classification. However, classical NB classifiers with multinomial, Bernoulli and Gaussian event models are not fully Bayesian. This study proposes three Bayesian counterparts, where it turns out that classical NB classifier with Bernoulli event model is equivalent to Bayesian counterpart. Finally, experimental results on 20 newsgroups and WebKB data sets show that the performance of Bayesian NB classifier with multinomial event model is similar to that of classical counterpart, but Bayesian NB classifier with Gaussian event model is obviously better than classical counterpart.
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Organic electrosynthesis has been widely used as an environmentally conscious alternative to conventional methods for redox reactions because it utilizes electric current as a ...traceless redox agent instead of chemical redox agents. Indirect electrolysis employing a redox catalyst has received tremendous attention, since it provides various advantages compared to direct electrolysis. With indirect electrolysis, overpotential of electron transfer can be avoided, which is inherently milder, thus wide functional group tolerance can be achieved. Additionally, chemoselectivity, regioselectivity, and stereoselectivity can be tuned by the redox catalysts used in indirect electrolysis. Furthermore, electrode passivation can be avoided by preventing the formation of polymer films on the electrode surface. Common redox catalysts include N-oxyl radicals, hypervalent iodine species, halides, amines, benzoquinones (such as DDQ and tetrachlorobenzoquinone), and transition metals. In recent years, great progress has been made in the field of indirect organic electrosynthesis using transition metals as redox catalysts for reaction classes including C–H functionalization, radical cyclization, and cross-coupling of aryl halides-each owing to the diverse reactivity and accessible oxidation states of transition metals. Although various reviews of organic electrosynthesis are available, there is a lack of articles that focus on recent research progress in the area of indirect electrolysis using transition metals, which is the impetus for this review.
In light of high energy density, hydrogen has been recognized as a promising clean energy carrier to defuse the coming energy crises. Among the many technological strategies ever tried, the Al-H2O ...reaction is a rather favored way to produce hydrogen although it is always hindered by a layer of passive film on Al surface. Recently, a class of gallium-based room-temperature liquid metal (RTLM) is found to effectively activate the Al-water reaction which draws attentions to such an extremely simple hydrogen production method. To push forward further investigations of this newly emerging area, this article is dedicated to present an overview of the latest advancement of the hydrogen production from the RTLM activated direct Al-H2O reaction. Meanwhile, it also comprehensively interprets the mechanisms of the RTLM activated Al-H2O reaction in terms of electrochemistry, phase constituents, interface actions and energy transfer process, and then discusses four influencing factors dominating the reaction. Next, several unique phenomena of RTLM fed with Al driven by releasing hydrogen are also illustrated, offering a glimpse on the development of soft robots. In addition, theoretical and technological challenges lying behind such a hydrogen generation scheme are prospected. It is anticipated that the RTLM triggered Al-H2O reaction for an in-time and on-demand hydrogen generation will witness a ever bright future in the coming time.
The activation of ferroptosis is a new effective way to treat drug-resistant solid tumors. Ferroptosis is an iron-mediated form of cell death caused by the accumulation of lipid peroxides. The ...intracellular imbalance between oxidant and antioxidant due to the abnormal expression of multiple redox active enzymes will promote the produce of reactive oxygen species (ROS). So far, a few pathways and regulators have been discovered to regulate ferroptosis. In particular, the cystine/glutamate antiporter (System X
c
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), glutathione peroxidase 4 (GPX4) and glutathione (GSH) (System X
c
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/GSH/GPX4 axis) plays a key role in preventing lipid peroxidation-mediated ferroptosis, because of which could be inhibited by blocking System X
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/GSH/GPX4 axis. This review aims to present the current understanding of the mechanism of ferroptosis based on the System X
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/GSH/GPX4 axis in the treatment of drug-resistant solid tumors.
Objectives
To describe the biological characteristics of exosomes and to summarize the current status of stem cell‐derived exosomes on fracture healing. Meanwhile, future challenges, limitations and ...perspectives are also discussed.
Methods
Search and analyze the related articles in pubmed database through the multi‐combination of keywords like “stem cells”,”exosomes”,”bone regeneration” and “fracture healing”.
Conclusion
Stem cell‐derived exosome therapy for fracture healing has been enjoying popularity and is drawing increasing attention. This strategy helps to promote proliferation and migration of cells, as well as osteogenesis and angiogenesis, in the process of bone formation. Although the exact mechanisms remain elusive, exosomal miRNAs seem to play vital roles. Future studies are required to solve multiple problems before clinical application, including comprehensive and thorough understanding of exosomes, the exact roles of exosomes in regulating bone formation, and the optimal source, dose and frequency of treatment, as well as technical and safety issues. Moreover, studies based on fracture models of large animals are could offer guidance and are in demand.
Ferroptosis is an iron-dependent cell death, which is different from apoptosis, necrosis, autophagy, and other forms of cell death. The process of ferroptotic cell death is defined by the ...accumulation of lethal lipid species derived from the peroxidation of lipids, which can be prevented by iron chelators (e.g., deferiprone, deferoxamine) and small lipophilic antioxidants (e.g., ferrostatin, liproxstatin). This review summarizes current knowledge about the regulatory mechanism of ferroptosis and its association with several pathways, including iron, lipid, and cysteine metabolism. We have further discussed the contribution of ferroptosis to the pathogenesis of several diseases such as cancer, ischemia/reperfusion, and various neurodegenerative diseases (e.g., Alzheimer's disease and Parkinson's disease), and evaluated the therapeutic applications of ferroptosis inhibitors in clinics.
Tie strength has been examined as an antecedent of creativity. Although it has been discovered that international collaboration affects scientific performance, the effect of tie strength in the ...international collaboration network has been largely neglected. Based on international publications of 72 countries/regions published from 1993 to 2013, we combine descriptive and panel regression methods to examine how the bonding of strong collaboration ties contributes to countries' international scientific performance. Strong ties occur at an average rate of 1 in 4 collaborators, whereas countries/regions share on average 84% of articles with their strong-tie collaborators. Our quantitative results provide an explanation for this phenomenon in international collaboration: the establishment of a strong tie relationship contributes to above-average productivity and citation frequency for countries/regions. To further explore which types of strong ties tend to have stronger citation impact, we analyse the relationship between persistent and stable collaboration and publication citation impact. Experimental results show that international collaborations with greater persistence and moderate stability tend to produce high impact publications. It is noteworthy that when the collaboration period is divided into different time intervals, similar findings can be found after the same analysis procedure is carried out. This indicates that our conclusions are robust. Overall, this study provides quantitative insights into the added value of long-term commitment and social trust associated with strong collaborative partnerships in international collaboration.
Surface tension plays a core role in dominating various surface and interface phenomena. For liquid metals with high melting temperature, a profound understanding of the behaviors of surface tension ...is crucial in industrial processes such as casting, welding, and solidification, etc. Recently, the room temperature liquid metal （RTLM） mainly composed of gallium-based alloys has caused widespread concerns due to its increasingly realized unique virtues. The surface properties of such materials are rather vital in nearly all applications involved from chip cooling, thermal energy harvesting, hydrogen generation, shape changeable soft machines, printed electronics to 3D fabrication, etc. owing to its pretty large surface tension of approximately 700 mN/m. In order to promote the research of surface tension of RTLM, this paper is dedicated to present an overview on the roles and mechanisms of surface tension of liquid metal and summarize the latest progresses on the understanding of the basic knowledge, theories, influencing factors and experimental measure- ment methods clarified so far. As a practical technique to regulate the surface tension of RTLM, the fimdamental principles and applications of electrowetting are also interpreted. Moreover, the unique phenomena of RTLM surface tension issues such as surface tension driven self- actuation, modified wettability on various substrates and the functions of oxides are discussed to give an insight into the acting mechanism of surface tension. Furthermore, future directions worthy of pursuing are pointed out.
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