Abstract
Compact groups (CGs) of galaxies appear to be the densest galaxy systems containing a few luminous galaxies in close proximity to each other, which have a typical size of a few tens of ...kiloparsec in observation. On the other hand, in the modern hierarchical structure formation paradigm, galaxies are assembled and grouped in dark matter halos, which have a typical size of a few hundreds of kiloparsec. Few studies have explored the physical connection between the observation-based CGs and halo model-based galaxy groups to date. In this study, by matching the largest local CG catalog of Zheng & Shen to the halo-based group catalog of Yang et al., we find that CGs are physically heterogeneous systems and can be mainly separated into two categories, the isolated systems and those embedded in rich groups or clusters. By examining the dynamical features of CGs, we find that isolated CGs have systematically lower dynamical masses than noncompact ones at the same group luminosity, indicating a more evolved stage of isolated CGs. On the other hand, the embedded CGs are mixtures of chance alignments in poor clusters and recent infalling groups (substructures) of rich clusters.
Flexural toppling failure is a widespread issue in anti-dip bedding rock slopes. Rock bolts are usually employed to reinforce bedding rock slopes as they are low-cost and efficient. In this technical ...note, a mechanical model based on limit equilibrium theory is proposed to predict the stability of anti-dip bedding rock slopes locally reinforced by rock bolts. By considering a practical case, the proposed model is subsequently verified by comparing its results with numerical results using a discrete element method. Finally, we investigate the influence the positions of rock bolts have on the reinforcement effect. The results show that, for a given bolt angle, the reinforcement effect is controlled by the positions of the rock bolts. In particular, the installation position must start from the superimposed toppling zone (the zone within which the rock layers resemble superimposed cantilever beams). On the other hand, there is no reinforcement effect if the installation position starts from the cantilevered toppling zone (the zone within which the rock layers resemble individual cantilever beams). The method proposed provides theoretical guidance for the design of the reinforcements applied to anti-dip bedding rock slopes. The results produced should also help engineers to gain a better understanding of the reinforcement mechanisms underlying the action of the rock bolts used in anti-dip bedding rock slopes.
•A theoretical model reflecting the effect of local rock bolts is proposed.•Reinforcement effect of rock bolts relies on the reinforcement position.•Influence of the height of rock layer on the reinforcement effect is discussed.
In recent decades, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)-based polymeric materials have been extensively investigated as one of the most promising candidates for many ...organic electronics applications. PEDOT:PSS and its hybrids with inorganic nanostructural components potentially exhibit outstanding thermoelectric performance that is comparable to their traditional inorganic counterparts. In this review, we summarize the recent advances of PEDOT:PSS-based thermoelectric materials which are prepared
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either hybridizing with a variety of inorganic nanomaterials and carbon nanostructures or facile post-treatment including solvent, vapour and electrochemical treatments. The thermoelectric properties of PEDOT:PSS-based hybrid materials in various environments are also reviewed, and the future research focuses, challenges and opportunities of this type of materials are addressed at the end.
This paper summarizes the latest development of PEDOT:PSS-based composites with inorganic additives and carbon nanostructures for thermoelectric applications.
Heterostructures with abundant phase boundaries are compelling for surface-mediated electrochemical applications. However, rational design of such bifunctional electrocatalysts for efficient hydrogen ...and oxygen evolution reactions (HER and OER) is still challenging. Here, due to the well-matched lattice parameters, we easily achieved the epitaxy of two-dimensional ternary nickel thiophosphate (NiPS3) nanosheets with in-grown dinickel phosphide (Ni2P) through an in situ growth strategy. Density functional theory calculations reveal that the NiPS3/Ni2P heterojunction significantly decreases the kinetic barrier for hydrogen adsorption and accelerates electron transfer due to the built-in electric field at the epitaxial interfaces. The significantly improved electrocatalytic performance is shown to be closely related to the epitaxial interfacial area rather than the amount of secondary phase. Notably, the resultant NiPS3/Ni2P heterostructures enable an overall water splitting electrolyzer to achieve 50 mA cm–2 at a lower bias of 1.65 V compared to that for the pristine NiPS3 alone (2.02 V) and even the benchmark Pt/C//IrO2 electrocatalysts (1.69 V).
With the increasing importance of offshore wind turbines, a critical issue in their construction is the high-performance concrete (HPC) used for grouting underwater foundations, as such materials ...must be better able to withstand the extremes of the surrounding natural environment. This study produced and tested 12 concrete sample types by varying the water/binder ratio (0.28 and 0.30), the replacement ratios for fly ash (0%, 10%, and 20%) and silica fume (0% and 10%), as substitutes for cement, with ground granulated blast-furnace slag at a fixed proportion of 30%. The workability of fresh HPC is discussed with setting time, slump, and V-funnel flow properties. The hardened mechanical properties of the samples were tested at 1, 7, 28, 56, and 91 days, and durability tests were performed at 28, 56, and 91 days. Our results show that both fly ash (at 20%) and silica fume (at 10%) are required for effective filling of interstices and better pozzolanic reactions over time to produce HPC that is durable enough to withstand acid sulfate and chloride ion attacks, and we recommend this admixture for the best proportioning of HPC suitable for constructing offshore wind turbine foundations under the harsh underwater conditions of the Taiwan Bank. We established a model to predict a durability parameter (i.e., chloride permeability) of a sample using another mechanical property (i.e., compressive strength), or vice versa, using the observable relationship between them. This concept can be generalized to other pairs of parameters and across different parametric categories, and the regression model will make future experiments less laborious and time-consuming.
Programmed cell death (PCD)—apoptosis, autophagy and programmed necrosis—is any pathological form of cell death mediated by intracellular processes. Ototoxic drugs, ageing and noise exposure are some ...common pathogenic factors of sensorineural hearing loss (SNHL) that can induce the programmed death of auditory hair cells through different pathways, and eventually lead to the loss of hair cells. Furthermore, several mutations in apoptotic genes including DFNA5, DFNA51 and DFNB74 have been suggested to be responsible for the new functional classes of monogenic hearing loss (HL). Therefore, in this review, we elucidate the role of these three forms of PCD in different types of HL and discuss their guiding significance for HL treatment. We believe that further studies of PCD pathways are necessary to understand the pathogenesis of HL and guide scientists and clinicians to identify new drug targets for HL treatment.
The authors review accumulating evidence pointing out that programmed cell death pathways, including apoptosis, autophagy and necrosis, play key roles in ultimate fates of auditory hair cells, when cells suffer adverse factors. These three forms of PCD may jointly decide occurrence of hearing loss.
Autophagy is a conserved feature of lysosome-mediated intracellular degradation. Dysregulated autophagy is implicated as a contributor in neurodegenerative diseases; however, the role of autophagy in ...retinal degeneration remains largely unknown. Here, we report that the photo-activated visual chromophore, all-trans-retinal, modulated autophagosome formation in ARPE19 retinal cells. Increased formation of autophagosomes in these cells was observed when incubated with 2.5 μm all-trans-retinal, a condition that did not cause cell death after 24 h in culture. However, autophagosome formation was decreased at concentrations, which caused cell death. Increased expression of activating transcription factor 4 (Atf4), which indicates the activation of oxidative stress, was recorded in response to light illumination in retinas of Abca4−/−Rdh8−/− mice, which showed delayed clearance of all-trans-retinal after light exposure. Expression of autophagosome marker LC3B-II and mitochondria-specific autophagy, mitophagy, regulator Park2, were significantly increased in the retinas of Abca4−/−Rdh8−/− mice after light exposure, suggesting involvement of autophagy and mitophagy in the pathogenesis of light-induced retinal degeneration. Deletion of essential genes required for autophagy, including Beclin1 systemically or Atg7 in only rod photoreceptors resulted in increased susceptibility to light-induced retinal damage. Increased photoreceptor cell death was observed when retinas lacking the rod photoreceptor-specific Atg7 gene were coincubated with 20 μm all-trans-retinal. Park2−/− mice also displayed light-induced retinal degeneration. Ultra-structural analyses showed mitochondrial and endoplasmic reticulum impairment in retinas of these model animals after light exposure. Taken together, these observations provide novel evidence implicating an important role of autophagy and mitophagy in protecting the retina from all-trans-retinal- and light-induced degeneration.
Background: Autophagy is a conserved process of lysosome-mediated intracellular degradation.
Results: Dysregulation of autophagy is associated with retinal cell death by all-trans-retinal and by light exposure.
Conclusion: Autophagy protects the retina from light-induced retinal degeneration.
Significance: Dynamic autophagy regulation may influence retinal cell survival under stress and disease conditions.
Soft-hard interbedded structures are commonly found in anti-dip rock slopes and endow the slopes with special properties. In this work, a simple two-beam model was first used to discuss the possible ...failure modes of rock layers with different lithology. The exact failure sequence of rock layers depends on their tensile strengths, elastic moduli, and thicknesses. Then, based on the deformation compatibility of rock layers, a novel theoretical method called the DCM for assessing the stability of soft-hard interbedded anti-dip rock slopes was proposed. A centrifuge test and a numerical model were used to verify the feasibility of the DCM. The calculated critical g-level of 47 g for the centrifuge model and a safety factor of 0.96 for the numerical model agree well with the results of the centrifuge test (45 g) and numerical simulation (0.98). Moreover, the traditional limit equilibrium method (LEM) was also adopted to explore these two models. The calculated results of 68 g and 1.79 using the traditional LEM were found to be much larger than the validated values, with deviations of more than 50%. This finding implies that the traditional LEM is not suitable for assessing the stability of soft-hard interbedded anti-dip rock slopes. In addition, the failure evolution of toppling failure in soft-hard interbedded anti-dip rock slopes was investigated using numerical modelling. The results show that the soft and hard rock layers do not fail at the same time; the rock layers of one type of lithology are destabilized first, then the other rock layers begin to fail until the entire slope undergoes flexural toppling.
•An analytical method is proposed for assessing the stability of soft-hard interbedded anti-dip rock slopes.•The failure sequences of rock layers in a compatible deformation zone can be judged.•The proposed method has high calculation accuracy and can be applied in practice.
•Amino acid decarboxylase (ADD) sequences vary lesser among bacterial species than between bacteria and fungi.•ADD sequences in Lactobacillus are not always of high similarity with those in other ...bacteria.•Most ADDs are predicted as stable cytosolic endoenzymes.•Molecular docking results suggest that the components of pepper, chili, and ginger may inhibit AADs by binding with their active sites.
Microbial amino acid decarboxylases (AADs) produce biogenic amines (BAs) in fermented food. However, a systematic comparison of the AADs’ properties from different microorganisms in pickle fermentation remains unexplored. Here, we bioinformatically analyzed the amino acid sequences of AADs corresponding to four major BAs for common microorganisms in pickle fermentation. We showed that their sequences, besides tyrosine decarboxylase, differed among microorganisms. Overall, the AAD sequences varied lesser among bacterial species than between bacteria and fungi, with those in Lactobacillus sharing occasionally high similarity with other bacteria. Most AADs were predicted as stable cytosolic endoenzymes. Molecular docking showed that most commonly used spice components in pickle production, especially pepper, chili, and ginger, strongly bind to the AAD active sites, thus may inhibit the enzymes and reduce the BA accumulation. This study provides insights for deeply understanding the different microbial AAD properties in pickle fermentation and reducing BAs by appropriately using spices.
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