Study on the mechanism of methane "solid-liquid-gas" conversion controlled by the evolution of coal micro- and nanopore structure.

Currently, the utilization of coalbed methane resources in the Guizhou region faces challenges such as complex reservoir structure, high gas content, and microporous development. Based on these, the pore structure and adsorption capacity of Guizhou tectonic deformed coals (TDCs) were evaluated using a suite of integrated diagnostic techniques including low-temperature nitrogen adsorption (LT-N2A), mercury intrusion porosimetry (MIP), methane isothermal adsorption. Through the above methods, the pore structure and adsorption characteristics of the samples were characterized; The samples were divided into the range of joint pores by combining the results of MIP and LT-N2A; Using the molecular simulation software, the 2 nm, 4 nm, 10 nm pores affecting the methane endowment state were investigated respectively, and from the perspective of the heat of adsorption and energy, the concept of the three-phase transition of methane was proposed, and explore the change of the pore spacing affecting the endowment state of methane from the solid state pore to the gas state pore. The results provide new ideas for the in-depth study of gas storage in tectonic coal reservoirs in Guizhou Province.

Experimental research on the influence of acid on the chemical and pore structure evolution characteristics of Wenjiaba tectonic coal.

The chemical and pore structures of coal play a crucial role in determining the content of free gas in coal reservoirs. This study focuses on investigating the impact of acidification transformation on the micro-physical and chemical structure characteristics of coal samples collected from Wenjiaba No. 1 Mine in Guizhou. The research involves a semi-quantitative analysis of the chemical structure parameters and crystal structure of coal samples before and after acidification using Fourier Transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) experiments. Additionally, the evolution characteristics of the pore structure are characterized through high-pressure mercury injection (HP-MIP), low-temperature nitrogen adsorption (LT-N2A), and scanning electron microscopy (SEM). The experimental findings reveal that the acid solution modifies the structural features of coal samples, weakening certain vibrational structures and altering the chemical composition. Specifically, the asymmetric vibration structure of aliphatic CH2, the asymmetric vibration of aliphatic CH3, and the symmetric vibration of CH2 are affected. This leads to a decrease in the contents of -OH and -NH functional groups while increasing aromatic structures. The crystal structure of coal samples primarily dissolves transversely after acidification, affecting intergranular spacing and average height. Acid treatment corrodes mineral particles within coal sample cracks, augmenting porosity, average pore diameter, and the ratio of macro-pores to transitional pores. Moreover, acidification increases fracture width and texture, enhancing the connectivity of the fracture structure in coal samples. These findings provide theoretical insights for optimizing coalbed methane (CBM) extraction and gas control strategies.

The reciprocity of skeletal muscle and bone: an evolving view from mechanical coupling, secretory crosstalk to stem cell exchange.

Introduction: Muscle and bone constitute the two main parts of the musculoskeletal system and generate an intricately coordinated motion system. The crosstalk between muscle and bone has been under investigation, leading to revolutionary perspectives in recent years. Method and results: In this review, the evolving concept of muscle-bone interaction from mechanical coupling, secretory crosstalk to stem cell exchange was explained in sequence. The theory of mechanical coupling stems from the observation that the development and maintenance of bone mass are largely dependent on muscle-derived mechanical loads, which was later proved by Wolff's law, Utah paradigm and Mechanostat hypothesis. Then bone and muscle are gradually recognized as endocrine organs, which can secrete various cytokines to modulate the tissue homeostasis and remodeling to each other. The latest view presented muscle-bone interaction in a more direct way: the resident mesenchymal stromal cell in the skeletal muscle, i.e., fibro-adipogenic progenitors (FAPs), could migrate to the bone injury site and contribute to bone regeneration. Emerging evidence even reveals the ectopic source of FAPs from tissue outside the musculoskeletal system, highlighting its dynamic property. Conclusion: FAPs have been established as the critical cell connecting muscle and bone, which provides a new modality to study inter-tissue communication. A comprehensive and integrated perspective of muscle and bone will facilitate in-depth research in the musculoskeletal system and promote novel therapeutic avenues in treating musculoskeletal disorders.

Acidification-Induced Micronano Mechanical Properties and Microscopic Permeability Enhancement Mechanism of Coal.

An acid solution improves the pore-plugging problem in hydraulic fracturing, which in turn improves the permeability of the coal seam. The study aimed to investigate the effect of mixed acid on the micronano mechanical properties and permeability of the coal seam. The surface morphology of acidified coal was analyzed from the micronano scale using atomic force microscopy (AFM) and scanning electron microscopy. Additionally, the micronano scale mechanical characteristics of acidified coal were examined using the mechanical mode in an atomic force microscope. Furthermore, the complexity and connectivity of the micronano pores of samples were investigated using the low-temperature nitrogen adsorption and mercury intrusion porosimetry methods and the fractal theory. The results indicated that the surface minerals of acidified coal were dissolved, loosening the coal and increasing the complexity of the pore structure. Mineral deformation and pore deformation weakened the mechanical properties of coal at the micronano scale, and the mean elastic modulus of acidified coal (B# and E#) decreased by 28.78 and 25.66% compared to that of raw coal. The acid solution effectively enlarged the pore diameter, transitioning from micropores to mesopores and macropores, and the total pore volume of acidified coal increased by 1.88 times and 1.25 times, Kn increased from 0.064 to 0.581 and 0.37, respectively. The type of methane diffusion in the diffusion pores changed from Knudsen diffusion to transition-type diffusion. The tortuosity of the pore structure of acidified coal decreased, the fractal dimension of the tortuosity of the pore structure decreased, and the permeability increased by nearly three times. The research results indicate that the mechanical properties of coal decrease after acidification and that the microstructural changes can promote methane migration (diffusion-seepage), which can provide theoretical guidance for coalbed methane extraction in low-permeability coal reservoirs.

The geological factors affecting gas content and permeability of coal seam and reservoir characteristics in Wenjiaba block, Guizhou province.

The gas content and permeability of coal reservoirs are the main factors affecting the productivity of coalbed methane. To explore the law of gas content and permeability of coal reservoirs in the Zhijin area of Guizhou, taking No.16, No.27 and No.30 coal seams in Wenjiaba mining area of Guizhou as the engineering background, based on the relevant data of coalbed methane exploration in Wenjiaba block, the geological structure, coal seam thickness, coal quality characteristics,coal seam gas content and permeability of the area were studied utilizing geological exploration, analysis of coal components and methane adsorption test. The results show that the average thickness of coal seams in this area is between 1.32 and 1.85 m; the average buried depth of the coal seam is in the range of 301.3-384.2 m; the gas content of No.16 and No.27 coal seams is higher in the syncline core. The gas content of the No.30 coal seam forms a gas-rich center in the south of the mining area. The buried depth and gas content of coal seams in the study area show a strong positive correlation. Under the same pressure conditions, the adsorption capacity of dry ash-free basis is significantly higher than that of air-dried coal. The permeability decreases exponentially with the horizontal maximum principal stress and the horizontal minimum principal stress. The horizontal maximum primary stress and the flat minimum prominent stress increase with the increase of the buried depth of the coal seam. The permeability and coal seam burial depth decrease exponentially. This work can provide engineering reference and theoretical support for selecting high-yield target areas for CBM enrichment in the block.

Influences of Evolution of Pore Structures in Tectonic Coal under Acidization on Methane Desorption.

Experiments on corrosion reactions of pulverized coal with monomeric and polymeric (mixed) acid solutions reveal that monomeric acids are listed in a descending order as HF, HCl, and CH3COOH according to their corrosion effects on tectonic coal collected in Faer Coal Mine (Liupanshui City, Guizhou Province, China). In addition, the optimal mixing ratio of mixed acids is 6% HCl + 6% HF + 3% CH3COOH + 2% KCl. The mineral grains filled in pores in coal samples treated with mixed acid solutions are dissolved, so the porosity increases. The volumes of transition pores and mesopores are obviously affected by acidization, and some transition pores are transformed into mesopores and macropores to form dissolved pores. At the same time, inkbottle-shaped pores reduce, while slit pores or open pores increase. The coal samples after acidization show a higher aromatization degree and an increased relative content of oxygen-containing functional groups, with a generally lower hydroxyl content, so the methane (CH4) adsorption capacity of coal declines, which promotes CH4 desorption. The control effect of pore structures after acidization reactions on CH4 desorption was revealed from perspectives of the diffusion coefficient (Kn), adsorption volume (ω), average pore-throat ratio (PT), and average sinuosity (τav). That is, CH4 molecules in tectonic coal after acidization turn from Knudsen diffusion to transitional diffusion, the adsorption volume of CH4 molecules shrinks, the average pore-throat ratio decreases, and the average sinuosity reduces, which promotes CH4 desorption from tectonic coal.

Predicting nonlinear multi-pulse propagation in optical fibers via a lightweight convolutional neural network.

The nonlinear evolution of ultrashort pulses in optical fiber has broad applications, but the computational burden of convolutional numerical solutions necessitates rapid modeling methods. Here, a lightweight convolutional neural network is designed to characterize nonlinear multi-pulse propagation in highly nonlinear fiber. With the proposed network, we achieve the forward mapping of multi-pulse propagation using the initial multi-pulse temporal profile as well as the inverse mapping of the initial multi-pulse based on the propagated multi-pulse with the coexistence of group velocity dispersion and self-phase modulation. A multi-pulse comprising various Gaussian pulses in 4-level pulse amplitude modulation is utilized to simulate the evolution of a complex random multi-pulse and investigate the prediction precision of two tasks. The results obtained from the unlearned testing sets demonstrate excellent generalization and prediction performance, with a maximum absolute error of 0.026 and 0.01 in the forward and inverse mapping, respectively. The approach provides considerable potential for modeling and predicting the evolution of an arbitrary complex multi-pulse.

A Novel Method Based on Hydrodynamic Cavitation for Improving Nitric Oxide Removal Performance of NaClO2.

In the removal of nitric oxide (NO) by sodium chlorite (NaClO2), the NaClO2 concentration is usually increased, and an alkaline absorbent is added to improve the NO removal efficiency. However, this increases the cost of denitrification. This study is the first to use hydrodynamic cavitation (HC) combined with NaClO2 for wet denitrification. Under optimal experimental conditions, when 3.0 L of NaClO2 with a concentration of 1.00 mmol/L was used to treat NO (concentration: 1000 ppmv and flow rate: 1.0 L/min), 100% of nitrogen oxides (NOx) could be removed in 8.22 min. Furthermore, the NO removal efficiency remained at 100% over the next 6.92 min. Furthermore, the formation of ClO2 by NaClO2 is affected by pH. The initial NOx removal efficiency was 84.8-54.8% for initial pH = 4.00-7.00. The initial NOx removal efficiency increases as the initial pH decreases. When the initial pH was 3.50, the initial NOx removal efficiency reached 100% under the synergistic effect of HC. Therefore, this method enhances the oxidation capacity of NaClO2 through HC, realizes high-efficiency denitrification with low NaClO2 concentration (1.00 mmol/L), and has better practicability for the treatment of NOx from ships.

Physics-based deep learning for modeling nonlinear pulse propagation in optical fibers.

A physics-based deep learning (DL) method termed Phynet is proposed for modeling the nonlinear pulse propagation in optical fibers totally independent of the ground truth. The presented Phynet is a combination of a handcrafted neural network and the nonlinear Schrödinger physics model. In particular, Phynet is optimized through physics loss generated by the interaction between the network and the physical model rather than the supervised loss. The inverse pulse propagation problem is leveraged to exemplify the performance of Phynet when in comparison to the typical DL method under the same structure and datasets. The results demonstrate that Phynet is able to precisely restore the initial pulse profiles with varied initial widths and powers, while revealing a similar prediction accuracy compared with the typical DL method. The proposed Phynet method can be expected to break the severe bottleneck of the traditional DL method in terms of relying on abundant labeled data during the training phase, which thus brings new insight for modeling and predicting the nonlinear dynamics of the fibers.

The relationship between physical activity and prosocial behavior of college students: A mediating role of self-perception.

OBJECTIVE: To explore the relationship between physical activity and prosocial behavior in college students, and to examine whether self-perception and gender may play mediating and moderating roles, respectively, in that relationship. METHODS: The International Physical Activity Questionnaire-long form, Prosocial Tendencies Measure, and Self-perception Scale were used to survey 647 college students in Yangzhou, China. Internal consistency testing, one-way analyses of variance (ANOVAs) across physical activity levels, exploratory factor analysis, correlation testing, mediation effect testing (independent variable, physical activity; mediating variable, self-perception; dependent variable, prosocial behavior), bootstrap testing and moderated mediation testing were conducted. RESULTS: Physical activity level was not found to be a direct predictor prosocial behavior in college students. Self-perception was found to play a mediating role between physical activity and prosocial behavior. CONCLUSION: Physical activity is not directly predictive college students' prosocial behavior tendencies, but it is indirectly predictive through self-perception. This study explores the relationship between the three variables and the path of the relationship, deepening the research related to the relationship between physical activity and prosocial behavior, providing ideas for fostering prosocial behavior in Chinese universities, as well as providing a theoretical basis for possible future empirical research.

[The Role of Histone Demethylase in Osteogenic and Chondrogenic Differentiation of Mesenchymal Stem Cells: A Literature Review].

The proliferation and multi-directional differentiation potential of mesenchymal stem cells (MSCs) enabled its wide use in the development of new therapies for bone and cartilage repair. Although preliminary work has been done to verify the gene expression profile of MSCs osteogenic and chondrogenic differentiation, it is still unclear what key factors initiate the differentiation of MSCs, resulting in its limited application in bone and cartilage tissue engineering. The epigenetic mechanism mediated by histone demethylases (lysine [K]-specific histone demethylases, KDMs) is the key link in regulating MSCs lineage differentiation. The lysine-specific histone demethylase (LSD) family containing Tower domain and the histone demethylase family containing Jumonji C (JmjC) domain regulate the expression of various osteogenic-related genes, including Runt-related transcription factor 2 ( RUNX2), osterix ( OSX), osteocalcin ( OCN), to mediate MSCs osteogenic differentiation. The KDM2/4/6 subfamilies regulate the chondrogenic differentiation of MSCs through multiple pathways centered on SRY-related high-mobility-group-box gene 9 ( SOX9). In addition, nanotopology, mircoRNAs, etc. regulate the expression of a variety of osteogenic and chondrogenic transcription factors through up- and down-regulation of KDMs. In summary, the role of histone demethylase in the osteogenic and chondrogenic differentiation of mesenchymal stem cells will help us better understand the pathogenesis of bone and cartilage damage diseases, and establish the foundation of future clinical applications for bone and cartilage tissue engineering.

Space Optimized Plane Wave Imaging for Fast Ultrasonic Inspection with Small Active Aperture: Simulation and Experiment.

Plane wave imaging (PWI) is attracting more attention in industrial nondestructive testing and evaluation (NDT&E). To further improve imaging quality and reduce reconstruction time in ultrasonic imaging with a limited active aperture, an optimized PWI algorithm was proposed for rapid ultrasonic inspection, with the comparison of the total focusing method (TFM). The effective area of plane waves and the space weighting factor were defined in order to balance the amplitude of the imaging area. Experiments were carried out to contrast the image quality, with great agreement to the simulation results. Compared with TFM imaging, the space-optimized PWI algorithm demonstrated a wider dynamic detection range and a higher defects amplitude, where the maximum defect amplitude attenuation declined by 6.7 dB and average attenuation on 12 defects decreased by 3.1 dB. In addition, the effects of plane wave numbers on attenuation and reconstruction time were focused on, achieving more than 10 times reduction of reconstruction times over TFM.

Mechanism for the reactivation of the peroxidase activity of human cyclooxygenases: investigation using phenol as a reducing cosubstrate.

It has been known for many years that the peroxidase activity of cyclooxygenase 1 and 2 (COX-1 and COX-2) can be reactivated in vitro by the presence of phenol, which serves as a reducing compound, but the underlying mechanism is still poorly understood. In the present study, we use phenol as a model compound to investigate the mechanism by which the peroxidase activity of human COXs is reactivated after each catalytic cycle. Molecular docking and quantum mechanics calculations are carried out to probe the interaction of phenol with the peroxidase site of COXs and the reactivation mechanism. It is found that the oxygen atom associated with the Fe ion in the heme group (i.e., the complex of Fe ion and porphyrin) of COXs can be removed by addition of two protons. Following its removal, phenol can readily bind inside the peroxidase active sites of the COX enzymes, and directly interact with Fe in heme to facilitate electron transfer from phenol to heme. This investigation provides theoretical evidence for several intermediates formed in the COX peroxidase reactivation cycle, thereby unveiling mechanistic details that would aid in future rational design of drugs that target the peroxidase site.

[Feeding habits of Saurida elongata in Haizhou Bay, Shandong, China, based on stomach contents and stable isotope.] / åŸºäºŽèƒƒå«ç‰©å’Œç¨³å®šåŒä½ç´ ç ”ç©¶æµ·å·žæ¹¾é•¿è›‡é²»çš„æ‘„é£Ÿä¹ æ€§.

Saurida elongata, a warm-water offshore benthic fish, is one of the dominant species in Haizhou Bay and plays an important role in the food web. Based on samples collected from bottom trawl surveys in Haizhou Bay, we examined the feeding habits of Saurida elongata based on both stomach content and stable isotope analyses. The results showed that the main prey species of Saurida elongata were Metapenaeopsis dalei, Loligo spp., Cryptocentrus filifer, Engraulis japonicus, Chaeturichthys hexanema, Apogonichthys lineatus, Syngnathus acus and Callionymus beniteguri. The range of δ13C value was -19.39‰ to -16.23‰, with an average value of (-18.01±0.85)‰. There was no correlation between body length and δ13C values. The value of δ15N ranged from 9.56‰ to 13.36‰, with an average value of (11.77±0.86)‰, which was significantly positively correlated with body length. There was substantial difference in the contribution of food organism among diffe-rent body length groups. With the increases of body size, predation ability and morphology of feeding organs gradually improved, and the proportion of prey organisms changed, which might be the main reason for the ontogenetic variation in feeding habits. This study could contribute to understand the feeding ecology of snake mullet in Haizhou Bay and provide basic information for the nutritional dynamics of the Haizhou Bay food web.

Ellagic acid, a plant phenolic compound, activates cyclooxygenase-mediated prostaglandin production.

In recent years, ellagic acid (EA), a naturally-occurring phenolic compound richly contained in some of the human food sources such as Longan and Litchi, was reported to have a number of biological effects. Based on our earlier 3D-QSAR/CoMFA models for cyclooxygenase (COX) I and II, we hypothesize that EA may have the potential to modulate the catalytic activity of COX enzymes, and this hypothesis is examined in the present study. The results from both in vitro and in vivo experiments show that EA is an activator of COX enzyme-catalyzed production of prostaglandin E2, a representative prostaglandin tested. Mechanistically, EA can activate the peroxidase active site of COX enzymes by serving as a co-substrate, presumably for the reduction of protoporphorin IX with FeIV inside. The effect of EA is abrogated by the co-presence of galangin, which is known to bind to COX's peroxidase active site and thereby blocks the effect of the reducing co-substrates. In view of the known physiological functions of COX enzymes in the body, it is suggested that some of the pharmacological and/or toxicological effects of EA may result from an increased production of certain prostaglandins and their related derivatives in the body.

Advance in High-intensity Interval Training for Acute Myocardial Infarction post Percutaneous Coronary Intervention (review) / 中国康复理论与实践

For the low-risk or stable patients with acute myocardial infarction post percutaneous coronary intervention, compared with moderate-intensity continuous training, high-intensity interval training (HIIT) can better enhance aerobic capacity and protect the cardiovascular system by significantly lowering the inflammatory response, improving endothelial function as well as reversing the progress of ventricular remodeling. HIIT is safety and the patients are more compliant. However, further research is needed on the application of high-risk patients. The standard protocol of HIIT according to the risk stratification also requires further discussion.

Stimulation of the Production of Prostaglandin E2 by Ethyl Gallate, a Natural Phenolic Compound Richly Contained in Longan.

Ethyl gallate is a phenolic compound richly contained in Longan. In traditional Chinese medicine, Longan is widely known as a fruit with "hot" properties, with a tendency to promote inflammatory and certain other responses. The mechanism for its proinflammatory as well as health beneficial effects is poorly understood. Based on our earlier observation that certain natural phenolic compounds can serve as reducing cosubstrates for cyclooxygenases (COXs), we sought to test a hypothesis that ethyl gallate may activate the catalytic activity of the COX enzymes. Results from studies using cultured cells and animals show that ethyl gallate can activate the production of prostaglandin E2, a representative prostaglandin tested in this study. Computational analysis indicates that ethyl gallate can activate the peroxidase active sites of COX-1 and COX-2 by serving as a reducing cosubstrate. The effect of ethyl gallate is abrogated by galangin, which is known to bind to the same peroxidase active sites of COX-1 and COX-2 as a competitive inhibitor. The findings of this study offer support for a novel hypothesis that the proinflammatory as well as health beneficial effects of Longan may partly attributable to the activation of COX-1 and COX-2 by ethyl gallate.

[Feeding habits of Rhinogobius pflaumi in Jiaozhou Bay, China based on carbon and nitrogen stable isotope analysis]. / åŸºäºŽç¢³ã€æ°®ç¨³å®šåŒä½ç´ ç ”ç©¶èƒ¶å·žæ¹¾æ™®æ°æ ‰è™¾è™Žé±¼çš„æ‘„é£Ÿä¹ æ€§.

Rhinogobius pflaumi is a small-sized, warm-temperate demersal fish species. It is one of the dominant species in fish community, and plays an important role in Jiaozhou Bay ecosystem. The trophic level and feeding habits of R. pflaumi were investigated by carbon and nitrogen stable isotope analysis, based on the data collected from the bottom trawl surveys during May 2011 in Jiaozhou Bay, China in this study. The results showed that the δ15N and δ13C values of R. pflaumi ranged from 11.24‰ to 13.99‰ and -20.67‰ to -18.46‰, respectively. The mean values of δ15N and δ13C were (12.70±0.70)‰ and (-19.08±0.36)‰, respectively. The mean trophic level of R. pflaumi was (3.62±0.21) for all size classes, ranging from 3.49 to 3.76 for different size classes. There was a significant negative correlation between the δ15N values and standard length, while no significant correlation was observed between δ13C values and standard length. The main prey groups of R. pflaumi were polychaeta, decapoda and mollusca. The trophic contributions of zooplankton and particle organic matter (POM) were relatively low. The similarities of prey species composition among different size classes were more than 92%, indicating that there was no significant difference in feeding habits with different standard lengths. R. pflaumi was an intermediate consumer in Jiaozhou Bay ecosystem. The significant negative correlation between trophic level and standard length might be due to variation in the proportion of different prey groups.