DEM Investigation of Particle-Scale Mechanical Properties of Frozen Soil Based on the Nonlinear Microcontact Model Incorporating Rolling Resistance

Although frozen soil is in nature the discrete material, it is generally treated as the continuum material. The mechanical properties of frozen soil are so complex to describe adequately by conventional continuum mechanics method. In this study, the nonlinear microcontact model incorporating rolling resistance is proposed to investigate the particle-scale mechanical properties of frozen soil. The failure mechanism of frozen soil is explicated based on the evolution of contact force chains and propagation of microcracks. In addition, the effects of contact stiffness ratio and friction coefficient on stress-strain curve and energy evolution are evaluated. The results show that the nonlinear microcontact model incorporating rolling resistance can better describe the experimental data. At a higher axial strain, the contact force chains near shear band which can give rise to the soil arch effect rotate away from the shear band inclination but not so much as to become perpendicular to it. The propagation of microcracks can be divided into two phases. The stress-strain curve is strongly influenced by contact stiffness ratio. In addition, friction coefficient does not significantly affect the initial tangential modulus. Compared with frictional coefficient, the effect of contact stiffness ratio on stress-strain curve and energy evolution is greater

Effect of Pyrolysis Temperature on the Characterisation of Dissolved Organic Matter from Pyroligneous Acid

Dissolved organic matter (DOM) greatly influences the transformation of nutrients and pollutants in the environment. To investigate the effects of pyrolysis temperatures on the composition and evolution of pyroligneous acid (PA)-derived DOM, DOM solutions extracted from a series of PA derived from eucalyptus at five pyrolysis temperature ranges (240–420 °C) were analysed with Fourier transform infrared spectroscopy, gas chromatography–mass spectroscopy, and fluorescence spectroscopy. Results showed that the dissolved organic carbon content sharply increased (p 370 °C). The results of two-dimensional correlation spectroscopic analysis suggested that with increasing pyrolysis temperatures, the humic-acid-like substances became more sensitive than other fluorescent components. This study provides valuable information on the characteristic evolution of PA-derived DOM

Microfluidic spinning of topographical hollow fibers for the development of a 3D functional glomerulus in vitro

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Sestrin2 protects against hypoxic nerve injury by regulating mitophagy through SESN2/AMPK pathway

Hypoxia induced by high altitude can lead to severe neurological dysfunction. Mitophagy is known to play a crucial role in hypoxic nerve injury. However, the regulatory mechanism of mitophagy during this injury remains unclear. Recent studies have highlighted the role of Sestrin2 (SESN2), an evolutionarily conserved stress-inducible protein against acute hypoxia. Our study demonstrated that hypoxia treatment increased SESN2 expression and activated mitophagy in PC12 cells. Furthermore, the knock-out of Sesn2 gene led to a significant increase in mitochondrial membrane potential and ATP concentrations, which protected the PC12 cells from hypoxic injury. Although the AMPK/mTOR pathway was significantly altered under hypoxia, it does not seem to participate in mitophagy regulation. Instead, our data suggest that the mitophagy receptor FUNDC1 plays a vital role in hypoxia-induced mitophagy. Moreover, SESN2 may function through synergistic regulation with other pathways, such as SESN2/AMPK, to mediate cellular adaptation to hypoxia, including the regulation of mitophagy in neuron cells. Therefore, SESN2 plays a critical role in regulating neural cell response to hypoxia. These findings offer valuable insights into the underlying molecular mechanisms governing the regulation of mitophagy under hypoxia and further highlight the potential of SESN2 as a promising therapeutic target for hypoxic nerve injury

A global bibliometric and visualized analysis of bacterial biofilm eradication from 2012 to 2022

BackgroundTo deeply explore the dynamic trends, focal points and emerging topics of bacterial biofilm eradication field and provide novel insights for prospective research endeavors, the first global bibliometric and visualized analysis of the field was employed in this study.MethodsThe study meticulously curated articles and reviews concentrating on biofilm eradication from the Web of Science Core Collection (WoSCC) and identified literature published in 2012–2022 for further analysis, and the bibliometric and visualized analysis was performed to elucidate a clustering pattern in the domain with tools mainly including CiteSpace and VOSviewer.Results15,503 authors affiliated with 2,397 institutions spanning 96 countries or regions contributed to a corpus of 3,201 articles, containing 7,005 keywords. The USA emerged as a commanding vanguard in exploring the antibiofilm strategies and displaying pioneering initiatives within this sphere. The Chinese Academy of Sciences (CAS) emerged as the most prolific source of publications. Noteworthy among authors, Pandian Shunmugiah Karutha secured the lead in article contributions as well as co-citations while Deng Le with his team is poised to become a dominant influence in the future. Despite that, the extent of collaborative engagement across different institutions and authors appeared to fall short of its potential. Frontiers in Microbiology led the discourse by publishing a substantial body of articles and standing as the most recurrently co-cited publication. The most influential research domains encompassed “bacterial biofilm formation, “photodynamic therapy” and “phage therapy.” Recent trends and forefronts concentrate on intensifying research into facilitating the shift of multiple strategies for biofilm eradication from controlled lab settings or animal studies to real-world clinical environments.ConclusionFundamentally, this study presents a comprehensive scrutiny and reveals that the realm of bacterial biofilm eradication is undergoing rapid evolution, with even greater expansion anticipated in the times ahead. Subsequent scholars should emphasize the augmentation of collaborative efforts and focus their energies on emerging topics, thus contributing to break through current barriers in transitioning biofilm eradication strategies from the “fundamental” stage to “practical” application

Tangshen Formula Alleviates Hepatic Steatosis by Inducing Autophagy Through the AMPK/SIRT1 Pathway

Tangshen formula (TSF), a formula of Chinese herbal medicine, improves lipid metabolism in humans and animals with diabetic kidney disease. However, the effect and mechanism of TSF on nonalcoholic fatty liver disease (NAFLD) remain unclear. The activation of autophagy appears to be a potential mechanism for improving NAFLD. In the present study, we examined the therapeutic effect of TSF on hepatic steatosis and sought to explore whether its effect is related to activating autophagy. Here, we showed that TSF treatment significantly attenuated hepatic steatosis in both high-fat diet (HFD) and methionine choline-deficient diet (MCDD)-fed mice. Meanwhile, TSF reduced lipid accumulation in palmitate (PA)-stimulated HepG2 cells and primary mouse hepatocytes. Furthermore, TSF increased Sirtuin 1 (SIRT1) expression and promoted autophagy activation in vivo. TSF also improved PA-induced suppression of both SIRT1 expression and SIRT1-dependent autophagy, thereby alleviating intracellular lipid accumulation in vitro. In addition, TSF increased SIRT1 expression and induced autophagy in an adenosine monophosphate-activated protein kinase (AMPK)-dependent manner. Moreover, SIRT1 knockdown abolished the autophagy-inducing and lipid-lowering effects of TSF. In conclusion, TSF improved lipid accumulation and hepatic steatosis by inducing the AMPK/SIRT1 pathway-mediated autophagy

Structural and functional insight into the mechanism of an alkaline exonuclease from Laribacter hongkongensis

Alkaline exonuclease and single-strand DNA (ssDNA) annealing proteins (SSAPs) are key components of DNA recombination and repair systems within many prokaryotes, bacteriophages and virus-like genetic elements. The recently sequenced β-proteobacterium Laribacter hongkongensis (strain HLHK9) encodes putative homologs of alkaline exonuclease (LHK-Exo) and SSAP (LHK-Bet) proteins on its 3.17 Mb genome. Here, we report the biophysical, biochemical and structural characterization of recombinant LHK-Exo protein. LHK-Exo digests linear double-stranded DNA molecules from their 5′-termini in a highly processive manner. Exonuclease activities are optimum at pH 8.2 and essentially require Mg2+ or Mn2+ ions. 5′-phosphorylated DNA substrates are preferred over dephosphorylated ones. The crystal structure of LHK-Exo was resolved to 1.9 Å, revealing a ‘doughnut-shaped’ toroidal trimeric arrangement with a central tapered channel, analogous to that of λ-exonuclease (Exo) from bacteriophage-λ. Active sites containing two bound Mg2+ ions on each of the three monomers were located in clefts exposed to this central channel. Crystal structures of LHK-Exo in complex with dAMP and ssDNA were determined to elucidate the structural basis for substrate recognition and binding. Through structure-guided mutational analysis, we discuss the roles played by various active site residues. A conserved two metal ion catalytic mechanism is proposed for this class of alkaline exonucleases

Aspiration-dependent strategy persistence promotes cooperation in spatial prisoner's dilemma game

In this paper, we introduce an aspiration-dependent persistence into the spatial prisoner's dilemma game aimed at promoting cooperation in a population. Based on aspiration, a player could adjust his/her strategy persistence level during the evolutionary process. In particular, he/she will hold a strategy longer if it brings him/her a satisfactory payoff, otherwise he/she will decrease the time duration of keeping the present choice. We also introduce a tunable parameter to characterize the sensitivity of strategy persistence to aspiration and investigate the effects of the sensitivity on the evolution of cooperation. The results show that aspiration-dependent strategy persistence could effectively promote cooperation. At an intermediate aspiration, diverse strategy persistence levels among population could be formed during the evolution, which ultimately results in the highest cooperation level. Then, we present intuitive explanations for the existence of optimal aspiration by scrutinizing the microscopic evolution of cooperation. Moreover, we find that, in the population where individuals are more sensitive to aspiration, cooperation could be further promoted by assembling greater cooperator clusters with the help of diverse strategy persistence distribution. Our results highlight the more realistic scenario where aspiration-dependent persistence is involved in the spatial prisoner's dilemma game

Inequality-induced emotions might promote cooperation in evolutionary games

Two types of emotions, envy and guilt, could be induced when people encounter inequality; especially, persons who are disadvantaged may feel envy toward the ones at advantage, whereas those in superior positions may feel guilty. These two emotions can affect subjective evaluations of their own utilities. In most previous studies of evolutionary games, the payoffs gained from games are directly used for payoff comparison when individuals consider to imitate others’ strategies, regardless of the impacts caused by the inner emotions. Here, we introduce two types of inequality aversion in evolutionary games and assume that the inequality aversion can induce two different emotions and subsequently affect the utilities of individuals. We investigate how the inequality aversion affects the evolution of cooperation in spatial evolutionary games. The numerical simulation results show that envy makes the evolution of cooperation more difficult, while guilt can effectively promote cooperation. Moreover, we have provided some intuitive explanations by scrutinizing the microscopic evolutions of the strategy patterns for different types of players, which are categorized according to strategy and emotion. We find that, to cooperators and defectors, the two emotions have different influences on strategy transmission in different evolution stages, respectively. Roughly speaking, envy hinders cooperation by weakening cooperators, while guilt promotes cooperation by weakening defectors. Besides, we also study the effects of inequality aversion on payoff distribution and find that envy influences fairness negatively, whereas guilt plays a positive role in fairness

Environment-driven migration enhances cooperation in evolutionary public goods games

Migration plays a critical role in the evolution of cooperation under the framework of evolutionary game theory. Previous studies have demonstrated that individuals might make their migration decisions based on various information, for example, their current cooperative environments, potential advantages of new places, and their own aspirations. In reality, people may perceive environment information and make decisions based on these information. In this paper, we introduce an environment-driven migration into evolutionary public goods games which are carried out on a two-dimensional plane, where individuals decide whether to migrate according to the probabilities determined by the differences between the local and global cooperative environments. We find that such an environment-driven migration can effectively enhance cooperation. Furthermore, there exists an optimal migration noise that leads to a highest cooperation level. In addition, we also find that appropriate moving speeds and migration tendencies, as well as relatively low population densities in the model are more favorable to the evolution of cooperation