Differential scanning calorimetry (DSC) is a powerful tool to address some of the most challenging issues in glass science and technology, such as the nonequilibrium nature of the glassy state and ...the detailed thermodynamics and kinetics of glass-forming systems during glass transition, relaxation, rejuvenation, polyamorphic transition, and crystallization. The utility of the DSC technique spans across all glass-forming chemistries, including oxide, chalcogenide, metallic, and organic systems, as well as recently discovered metal–organic framework glass-forming systems. Here we present a comprehensive review of the many applications of DSC in glass science with focus on glass transition, relaxation, polyamorphism, and crystallization phenomena. We also emphasize recent advances in DSC characterization technology, including flash DSC and temperature-modulated DSC. This review demonstrates how DSC studies have led to a multitude of relevant advances in the understanding of glass physics, chemistry, and even technology.
The identification and resolution technology are the prerequisite for realizing identity consistency of physical-cyber space mapping in the Internet of Things (IoT). Face, as a distinctive noncoded ...and unstructured identifier, has especial advantages in identification applications. With the increase of face identification based applications, the requirements for computation, communication, and storage capability are becoming higher and higher. To solve this problem, we propose a fog computing based face identification and resolution scheme. Face identifier is first generated by the identification system model to identify an individual. Then, a fog computing based resolution framework is proposed to efficiently resolve the individual's identity. Some computing overhead is offloaded from a cloud to network edge devices in order to improve processing efficiency and reduce network transmission. Finally, a prototype system based on local binary patterns (LBP) identifier is implemented to evaluate the scheme. Experimental results show that this scheme can effectively save bandwidth and improve efficiency of face identification and resolution.
SnO2 is one of the most promising anode materials for lithium ion batteries (LIBs). However, its cycling stability is poor due to its large volume change, and hence, its practical applications in ...LIBs are hindered. In this work, we propose a novel and simple strategy to enhance the performances of SnO2-based anodes. This strategy involves optimized assembling of SnO2 with metal organic framework (MOF) and graphene. SnO2 nanoparticles are packed into Al-MOF in an optimum mass ratio, and then the derived SnO2@MOF composite is wrapped by graphene, finally resulting in the SnO2@MOF/graphene composite. This composite exhibits greatly enhanced cycling stability, i.e., the specific capacity is about 450 mA h g−1 after 1000 charge/discharge cycles at the current density of 1000 mA g−1. This is attributed to the unique structural configuration of the composite, which gives rich accessible electroactive sites, shortened ion transport pathways, and superior electronic conductivity. The MOF protection layer is a key for improving the lithium storage of metal oxide-based anodes. Although the capacity of the SnO2@MOF/graphene composite is not the highest among the existing anode materials, its synthesis process is simpler and cost effective.
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•SnO2@MOF/graphene composite was optimally assembled for Li-ion battery anodes.•The composite anode exhibits greatly enhanced lithium storage performance.•The enhanced cycling stability arises from the metal organic framework protection.•The wrapping graphene provides higher electronic conductivity.
Aqueous fluids are essential to extract slab‐trapped carbon at forearc to subarc depths and interpret the decarbonation efficiency of global subduction zones. A large amount of carbon survives beyond ...subarc depths. The behavior of such carbon, however, remains unclear owing to a lack of experimental studies. Here, we investigate the decarbonation behavior of carbonated oceanic crust containing different amounts of H2O at pressures from subarc depths to the top of the mantle transition zone. We find that calcium‐rich carbonatitic liquids can form at temperatures of ∼950–1,150°C at depths below ∼150–300 km, corresponding to warm/cold thermal regimes in most subduction zones. Therefore, hydrous carbonatitic liquids should be pervasive in subduction zones, while extensive dehydration reactions and fluid activities are critical for creating carbonatitic liquids and preventing most of the surviving carbon from being subducted into the deep Earth.
Plain Language Summary
The deep recycling of CO2 and H2O in subduction zones is key for understanding the habitability and climate change of Earth. Here, we use a high‐pressure and high‐temperature instrument, the multi‐anvil press, to investigate the fate of subducted carbon in oceanic crust. We find that H2O can depress the decarbonation temperature of subducted oceanic crust by hundreds of °C. Most of the surviving carbon that descends to depths below ∼150 km may be released into the upper mantle by hydrous carbonatitic liquids, rather than entering the lower mantle. The fate of such carbon has not been well constrained, but it is important to understand this process because CO2 released into the convecting upper mantle is key to constraining the origin of the deep carbon reservoir.
Key Points
Effect of H2O on the decarbonation behavior of subducted oceanic crust was investigated
Hydrous carbonatitic liquids can form at ∼950–1,150°C at depths below ∼150 km
Fluid activity is critical for removing most of the surviving carbon beyond subarc depths
Zinc and Yttrium single sites were introduced into the silanol nests of dealuminated BEA zeolite to produce Zn-DeAlBEA and Y-DeAlBEA. These materials were then investigated for the conversion of ...ethanol to 1,3-butadiene. Zn-DeAlBEA was found to be highly active for ethanol dehydrogenation to acetaldehyde and exhibited low activity for 1,3-butadiene generation. By contrast, Y-DeAlBEA was highly active for 1,3-butadiene formation but exhibited no activity for ethanol dehydrogenation. The formation of 1,3-butadine over Y-DeAlBEA and Zn-DeAlBEA does not occur via aldol condensation of acetaldehyde but, rather, by concerted reaction of coadsorbed acetaldehyde and ethanol. The active centers for this process are ≡Si–O–Y(OH)–O–Si≡ or ≡Si–O–Zn–O–Si–O≡ groups closely associated with adjacent silanol groups. The active sites in Y-DeAlBEA are 70 times more active than the Y sites supported on silica, for which the Y site is similar to that in Y-SiO2 but which lacks adjacent hydroxyl groups, and are 7 times more active than the active sites in Zn-DeAlBEA. We propose that C–C bond coupling in Y-DeAlBEA proceeds via the reaction of coadsorbed acetaldehyde and ethanol to form crotyl alcohol and water. The dehydration of crotyl alcohol to 1,3-butadiene is facile and occurs over the mildly Brønsted acidic ≡Si–OH groups present in the silanol nest of DeAlBEA. The catalysts reported here are notably more active than those previously reported for both the direct conversion of ethanol to 1,3-butadiene or the formation of this product by the reaction of ethanol and acetaldehyde.
Coordination of cell cycle with metabolism exists in all cell types that grow by division. It serves to build a new cell, (i) fueling building blocks for the synthesis of proteins, nucleic acids, and ...membranes, and (ii) producing energy through glycolysis. Cyclin-dependent kinases (Cdks) play an essential role in this coordination, thereby in the regulation of cell division. Cdks are functional homologs across eukaryotes and are the engines that drive cell cycle events and the clocks that time them. Their function is counteracted by stoichiometric inhibitors; specifically, inhibitors of cyclin-cyclin dependent kinase (cyclin/Cdk) complexes allow for their activity at specific times. Here, we provide a new perspective about the yet unknown cell cycle mechanisms impacting on metabolism. We first investigated the effect of the mitotic cyclin/Cdk1 complex Cyclin B/Cdk1—functional homolog in mammalian cells of the budding yeast Clb2/Cdk1—on yeast metabolic enzymes of, or related to, the glycolysis pathway. Six glycolytic enzymes (Glk1, Hxk2, Pgi1, Fba1, Tdh1, and Pgk1) were subjected to
in vitro
Cdk-mediated phosphorylation assays. Glucose-6-phosphate dehydrogenase (Zwf1), the first enzyme in the pentose phosphate pathway that is important for NADPH production, and 6-phospho-fructo-2-kinase (Pfk27), which catalyzes fructose-2,6-bisphosphate synthesis, a key regulator of glycolysis, were also included in the study. We found that, among these metabolic enzymes, Fba1 and Pgk1 may be phosphorylated by Cdk1, in addition to the known Cdk1-mediated phosphorylation of Gph1. We then investigated the possible effect of Sic1, stoichiometric inhibitor of mitotic cyclin/Cdk1 complexes in budding yeast, on the activities of three most relevant glycolytic enzymes: Hxk2, Glk1, and Tdh1. We found that Sic1 may have a negative effect on Hxk2. Altogether, we reveal possible new routes, to be further explored, through which cell cycle may regulate cellular metabolism. Because of the functional homology of cyclin/Cdk complexes and their stoichiometric inhibitors across evolution, our findings may be relevant for the regulation of cell division in eukaryotes.
The optimization of engineered metabolic pathways requires careful control over the levels and timing of metabolic enzyme expression. Optogenetic tools are ideal for achieving such precise control, ...as light can be applied and removed instantly without complex media changes. Here we show that light-controlled transcription can be used to enhance the biosynthesis of valuable products in engineered Saccharomyces cerevisiae. We introduce new optogenetic circuits to shift cells from a light-induced growth phase to a darkness-induced production phase, which allows us to control fermentation with only light. Furthermore, optogenetic control of engineered pathways enables a new mode of bioreactor operation using periodic light pulses to tune enzyme expression during the production phase of fermentation to increase yields. Using these advances, we control the mitochondrial isobutanol pathway to produce up to 8.49 ± 0.31 g l
of isobutanol and 2.38 ± 0.06 g l
of 2-methyl-1-butanol micro-aerobically from glucose. These results make a compelling case for the application of optogenetics to metabolic engineering for the production of valuable products.
Acanthopanax senticosus (AS), previously classified as Eleutherococcus senticosus, is one of the most commonly used herbs in the Chinese materia medica. However, there is currently no comprehensive ...review summarising advances in AS research. AS has been used as a functional food and in various preparations since ancient times, to invigorate the liver and kidneys, replenish vitality, strengthen the bones, stimulate appetite, and improve memory. It is widely used in countries such as China, Korea, Japan, and Russia, for specific pharmacologic effects, although it contains various chemical components that ensure its broad-spectrum effect. Its chemical constituents mainly include glycosides and flavonoids. Over the past several decades, researchers worldwide have conducted systematic investigations on this herb. AS has positive pharmacological effects on the cardiovascular, central nervous, and immune systems. Representative pathways stimulated by AS are related to neuroactive ligand-receptor interactions, cancer, and phosphatidylinositol 3 kinase/protein kinase B signalling. Importantly, AS is safe and exerts no significant adverse effects at normal doses.
To provide comprehensive insights into the ethnobotany, medicinal uses, chemical composition, pharmacological activity, and toxicology of AS to aid its future development and utilisation.
Information about AS was collected from various sources, including classic books about Chinese herbal medicine and scientific databases including scientific journals, books, and pharmacopoeia. We discuss the ethnopharmacology of AS from 1965 to 2020 and summarise the knowledge of AS phytochemicals, pharmacological activity, quality control, and toxicology.
From the current literature, we conclude that AS is a promising dietary Chinese herb with various potential applications owing to its multiple therapeutic effects.
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•A review on Acanthopanax senticosus (AS) was performed.•This review provides comprehensive insights into the toxicology of AS.•The medicinal use, phytochemicals, and pharmacological activity of AS are discussed.•Our findings will help in the further development and utilisation of AS resources.
Under the background of effectively building the legal system of the capital market and strengthening investor protection, an evaluation of whether China's legal system's reformations have improved ...investor protection is of great significance. Based on the lawsuits of 663 listed companies from 1997 to 2021, this paper finds the average annual proportion of listed companies punished by the China Securities Regulatory Commission and prosecuted by the investors is 40%, and since 2017, it has stabilized at around 70%. This paper also finds the “head effect” of the number of investors and claims in the misrepresentation cases over the years and the advantages of China Securities Investor Services Center's support in investor protection. Then, the negative binomial regression method is used to empirically find that investor protection gets better and better with the reformation of China's laws. Reformations in the legal system and key provisions have all led to an increase in the number of sued investors and claims. However, the time of legal proceedings only depends on the reform of the entire legal system. Finally, to reduce litigation costs and make all investors actually receive compensation after being infringed, we should establish the class action mechanism in the future reformation of China's legal system.
MgCo2O4 microflowers (MFs) assembled with porous nanosheets were prepared through a facile hydrothermal method with a post calcination treatment of the precursors at 400 °C for 3 h in air. No ...surfactant or template was used during the synthetic process. These MgCo2O4 MFs possessed a BET specific surface area of 39.1 m2 g−1 with an average pore size of 37 nm. The electrochemical performance was evaluated in a typical three-electrode system using 2 M of KOH aqueous solution as electrolyte, and the results indicated that such MgCo2O4 MFs exhibited a high specific capacitance of 749.2 F g−1 at 1 A g−1 as well as a high rate capability of approximate 73.3% with the current density increasing from 1 to 15 A g−1. After 5000 charge-discharge cycles at 5 A g−1, a specific capacitance of 435.3 F g−1 with 67.8% capacitance retention of its initial value and Coulombic efficiency of about 100% could be reached. In addition, an asymmetric supercapacitor (ASC) was fabricated with MgCo2O4 MFs as the positive electrode and activated carbon (AC) as the negative electrode. The ASC delivered a high energy density of 35.2 Wh kg−1 at a power density of 859.2 W kg−1. At a higher power density of 7415.3 W kg−1, the energy density still reached 29.3 Wh kg−1. The ASC also showed a good cycling stability with 100.9% specific capacitance retention after 5000 cycles at 5 A g−1. The unique MgCo2O4 MFs with mesoporous structures are beneficial for the rapid Faradic reactions because sufficient contact between electrolyte/electrode material and short diffusion path for ions/electrons can be ensured. The current synthesis is involved in simple operation and low cost, and can be extended to the preparation of other binary transitional metal oxides as electrode materials for the next-generation advanced supercapacitors.
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•Porous MgCo2O4 microflowers were hydrothermally synthesized.•A high specific capacitance of 749.2 F g−1 at 1 A g−1 was obtained.•73.3% rate capability was achieved with current density increasing from 1 to 15 A g−1•67.8% capacitance retention was obtained after 5000 cycles at 5 A g−1
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