In order to investigate the effect of hot isostatic pressing (HIP) process parameters on the properties and fracture behavior of tungsten alloy, HIP experiments with different process parameters were ...carried out, and the relative density, Rockwell hardness, tensile properties, and tensile fracture behavior were analyzed. The results show that after HIP, the tungsten alloy samples obtained further densification, higher relative density and hardness, and lower dispersity. At 1300 °C and 140 MPa, the sintered bar achieved excellent mechanical properties: yield strength increased by 16.5%, tensile strength increased by 16.1%, and fracture strength increased by 85.3%. Comparing the two processes, the mechanical properties of tungsten alloy powders formed directly via HIP were not as good as those of the sintered bars. In addition, after HIP, the fracture mode of the tungsten alloy sintered bar samples was mainly ductile tear, and that of the tungsten alloy powder samples was mainly a full brittle fracture.
The fresh or dried stems of many Dendrobium species are well known as one of the most expensive tonics in traditional Chinese medicine. Documented as a “superior grade” herbal medicine in the ancient ...text “Shen Nong’s Herbal Classic”, Dendrobium has been used for thousands of years and is now a popular health food worldwide. The main chemical components of Dendrobium are alkaloids, aromatic compounds, sesquiterpenoids and polysaccharides, with multiple biological activities, including immunomodulatory, neuroprotective and anti-tumor effects, etc. Various qualitative and quantitative methods have been developed for the quality evaluation of Dendrobium. In this review, the research progress since the 1930s relating to the chemistry, bioactivity and quality control of Dendrobium is summarized, existing problems and prospects are also discussed.
Mitochondria play a kay role in various cell processes including ATP production, Ca^2＋ homeostasis, reactive oxygen species （ROS） generation, and apoptosis. The selective removal of impaired ...mitochondria by autophagosome is known as mitophagy. Cerebral ischemia is a common form of stroke caused by insuf- ficient blood supply to the brain. Emerging evidence suggests that mitophagy plays important roles in the pathophysiological process of cerebral ischemia. This review focuses on the relationship between ischemic brain injury and mitophagy. Based on the latest research, it describes how the signaling pathways of mitophagy appear to be involved in cerebral ischemia.
Many anticancer agents exert cytotoxicity and trigger apoptosis through the induction of mitochondrial dysfunction. Mitophagy, as a key mitochondrial quality control mechanism, can remove damaged ...mitochondria in an effective and timely manner, which may result in drug resistance. Although the implication of mitophagy in neurodegenerative diseases has been extensively studied, the role and mechanism of mitophagy in tumorigenesis and cancer therapy are largely unknown. In a recent study, we found that the inhibition of PINK1-PRKN-mediated mitophagy can significantly enhance the anticancer efficacy of magnolol, a natural product with potential anticancer properties. On the one hand, magnolol can induce severe mitochondrial dysfunction, including mitochondrial depolarization, excessive mitochondrial fragmentation and the generation of mitochondrial ROS, leading to apoptosis. On the other hand, magnolol induces PINK1-PRKN-dependent mitophagy via activation of two rounds of feedforward amplification loops. The blockage of mitophagy through genetic or pharmacological approaches promotes rather than attenuates magnolol-induced cell death. Furthermore, inhibition of mitophagy by using distinct inhibitors targeting different mitophagic stages effectively enhances magnolol's anticancer efficacy in vivo. Taken together, our findings strongly indicate that manipulation of mitophagy in cancer treatment will be a promising therapeutic strategy for overcoming cancer drug resistance and improving the therapeutic efficacy of anticancer agents.
Clusters with diverse structures and functions have been used to create novel cluster‐assembled materials (CAMs). Understanding their self‐assembly process is a prerequisite to optimize their ...structure and function. Herein, two kinds of unlike organo‐functionalized inorganic clusters are covalently linked by a short organic tether to form a dumbbell‐shaped Janus co‐cluster. In a mixed solvent of acetonitrile and water, it self‐assembles into a crystal with a honeycomb superstructure constructed by hexagonal close‐packed cylinders of the smaller cluster and an orderly arranged framework of the larger cluster. Reconstruction of these structural features via coarse‐grained molecular simulations demonstrates that the cluster crystallization and the nanoscale phase separation between the two incompatible clusters synergistically result in the unique nano‐architecture. Overall, this work opens up new opportunities for generating novel CAMs for advanced future applications.
How to pack dumbbells: The size asymmetry and Janus characteristics of a dumbbell‐shaped co‐cluster synergistically define its self‐assembly in solution into crystals with a filled‐honeycomb superstructure. The Janus co‐cluster consists of a POM (purple sphere) and a POSS (green sphere) linked by an organic tether.
The physicochemical properties of four 1-alkyl-3-methylimidazolium bromide (C
C₁imBr, n = 5, 6, 7, 8) ionic liquids (ILs) were investigated in this work by using inverse gas chromatography (IGC) from ...303.15 K to 343.15 K. Twenty-eight organic solvents were used to obtain the physicochemical properties between each IL and solvent via the IGC method, including the specific retention volume and the Flory⁻Huggins interaction parameter. The Hildebrand solubility parameters of the four C
C₁imBr ILs were determined by linear extrapolation to be δ 2 ( C 5 C 1 im Br ) = 25.78 (J·cm
)
, δ 2 ( C 6 C 1 im Br ) = 25.38 (J·cm
)
, δ 2 ( C 7 C 1 im Br ) =24.78 (J·cm
)
and δ 2 ( C 8 C 1 im Br ) = 24.23 (J·cm
)
at room temperature (298.15 K). At the same time, the Hansen solubility parameters of the four C
C₁imBr ILs were simulated by using the Hansen Solubility Parameter in Practice (HSPiP) at room temperature (298.15 K). The results were as follows: δ t ( C 5 C 1 im Br ) = 25.86 (J·cm
)
, δ t ( C 6 C 1 im Br ) = 25.39 (J·cm
)
, δ t ( C 7 C 1 im Br ) = 24.81 (J·cm
)
and δ t ( C 8 C 1 im Br ) = 24.33 (J·cm
)
. These values were slightly higher than those obtained by the IGC method, but they only exhibited small errors, covering a range of 0.01 to 0.1 (J·cm
)
. In addition, the miscibility between the IL and the probe was evaluated by IGC, and it exhibited a basic agreement with the HSPiP. This study confirms that the combination of the two methods can accurately calculate solubility parameters and select solvents.
As the one of the most catastrophic hazards in underground mining, coal and gas outburst seriously threatens the safe mining of collieries. To understand the formation and transport mechanism of ...outburst coal-gas flow in roadway as well as evaluate the effects of gas desorption on its development, a new apparatus was developed to conduct simulated experiments with different gases of CO2 and N2. Results indicated that the outburst coal-gas flow was a high-speed (up to 41.02 m/s during tests) gas-solid two phases flow with extreme complexity, its transport/destructiveness characteristics were significantly influenced by a number of factors including the outburst pressure, coal sample composition, ejection distance and so on. Among these factors, the gas desorption showed the greatest impact when compared to the controlled tests which only considered the effect of free gas expansion. With the effect of gas desorption, especially the rapid gas desorption from powdered coal, the total outburst energy could be promoted by 1.30–2.43 times; the peak values of outburst shockwave could be enhanced by at least 13.67%–63.22%; the transport type of coal-gas flow could be changed from dynamic pressure pneumatic conveying to the static pressure conveying which providing higher capability for outburst coal/rock conveying; the motion of ejected coal flow could have higher speed, longer transport duration and could suffer secondary acceleration. As the result, the destructiveness of outburst coal-gas flow would be remarkably intensified.
A further analysis for the energy consumption during the outburst coal-gas flow transport indicated that the free gas expansion energy was insufficient for the conveying of ejected coal (only accounting for less than half of the total energy), the difference of which was made up by the gas desorption, especially the rapid gas desorption from powdered coal (the average contribution ratio reached 56.0%, while the maximum reached 64.1%). Thus, it can be concluded that the rapid gas desorption from powdered coal played a decisive role on the promotion of outburst.
•Formation and transport of outburst coal-gas flow and its affecting factors were investigated with a new apparatus.•The energy balance characteristics concerning the transport process of outburst coal-gas flow are analyzed.•The decisive role that rapid gas desorption from powdered coal plays on the development stage of outburst is revealed.
With the country's strong support for infrastructure, tunnel-related projects are also increasing daily. Combined with the current Internet of Things (IoT) technology booming, the realization of ...intelligent construction has become the mainstream direction of today's tunnel construction. This design is mainly realized by combining IOT communication technology, sensor technology, and microcontroller technology. STM32 microcontroller acts as the system's central processing unit and receives real-time information on gas concentration, smoke concentration, pipe wall pressure, and water level collected by various sensors, then displays the data on the LED display after data processing. When the environmental data exceeds the standard, it will automatically drive and adjust the water pumps and fans and simultaneously move the WiFi module to remotely send the data to the mobile phone APP through the Internet cloud server. When the environmental data exceeds the standard, it automatically drives and adjusts the water pump and fan while moving the WiFi module to remotely send the data to the cell phone APP through the Internet cloud server. After actual testing, the system can meet the design requirements and further improve the safety and convenience of tunnel construction.
Skew-orthogonal polynomials (SOPs) arise in the study of the
n
-point distribution function for orthogonal and symplectic random matrix ensembles. Motivated by the average of characteristic ...polynomials of the Bures random matrix ensemble studied in Forrester and Kieburg (Commun Math Phys 342(1):151–187,
2016
), we propose the concept of
partial-skew-orthogonal polynomials
(PSOPs) as a modification of the SOPs, and then the PSOPs with a variety of special skew-symmetric kernels and weight functions are addressed. By considering appropriate deformations of the weight functions, we derive nine integrable lattices in different dimensions. As a consequence, the tau-functions for these systems are shown to be expressed in terms of Pfaffians and the wave vectors PSOPs. In fact, the tau-functions also admit the multiple integral representations. Among these integrable lattices, some of them are known, while the others are novel to the best of our knowledge. In particular, one integrable lattice is related to the partition function of the Bures ensemble. Besides, we derive a discrete integrable lattice which can be used to compute certain vector Padé approximants. This yields the first example regarding the connection between integrable lattices and generalised inverse vector-valued Padé approximants, about which Hietarinta, Joshi, and Nijhoff pointed out that, “This field remains largely to be explored”, in the recent monograph (Hietarinta et al. in Discrete systems and integrability, vol 54. Cambridge University Press, Cambridge,
2016
, Section 4.4).
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