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Magma intrusion into coal seams is widely existed in China, and the structure and components of the coal body are changed after intrusion to form a high-order metamorphic coal, but its spontaneous combustion characteristics are not clear. It is a great significance to explore the effect of magma intrusion on the low-temperature oxidization characteristics of coal, and to prevent and control spontaneous combustion disasters in mining magma-eroded coal seams. Taking the −350 working face in the second mining area of the Xin'an Coal Mine as the engineering background, the coal samples were collected at different distances from the magma intrusion on the spot. By testing the industrial composition and analyzing the differences in the surface morphology of the samples, it was concluded that magma intrusion metamorphosed the raw coal and increased the number of pores and fissures on the surface, mainly through contact thermal evolution. The metamorphic coals were categorized into strongly eroded coals, weakly eroded coals, and high rank coals of the homogeneous group. Based on fixed carbon, ash, specular group reflectance, and paleo temperature, the distribution range of different intrusive metamorphic coals was calculated by curve backpropagation, and the influence range of magmatic intrusion was predicted to be about 172.34%−234.68% of the width of the intrusive body. A comparative study of the oxidative thermal effect of magma intrusion on metamorphic coal and raw coal was carried out by using C80 microcalorimeter. And the results showed that under different air supply conditions, compared with the original coal, the initial exothermic and thermal equilibrium temperature points in the low-temperature oxidation stage were advanced by 0.2−3.4 ℃ and 1.9−18.2 ℃ for strongly eroded, weakly eroded, and homogeneous high-order coals, the total exothermic capacity was increased by 1.72%−135.75%, and the apparent activation energy was reduced by 1.62%−69.02%, and the closer the metamorphic coal was to the magma intrusion, the more oxidizing and exothermic it was, and the shorter the natural ignition period was. Under the condition of sufficient oxygen supply, magma intrusion enhanced the exothermic capacity of oxidation reaction of the strongly eroded coal within the range of 1.01−2.68 m from the magma intrusion, and its mining volume only accounted for about 6.23%−12.15% of the influence range of the magma intrusion. Therefore, when mining back into the magma intrusion area, the prevention and control of spontaneous combustion of strongly eroded coal should be strengthened, and the critical value of the coal spontaneous combustion forecast index in this area should be corrected in time, so as to guarantee the safe mining of coal seams.

Abstract Effective coalbed methane extraction from soft coal seams is essential for mine safety and energy supply. To enhance the extraction efficiency of coal mine methane (CMM) and reduce the risk of gas outbursts in coal mining areas, we developed an original and innovate horizontal well hydraulic cavitation method. A mathematical model that can quantitatively optimize construction parameters and improve the effectiveness of engineering applications was also constructed to calculate the technological parameters of this construction method. This technology differs from traditional approaches by relying on hydraulic erosion rather than water jets, and it can be implemented in cased horizontal wells. Utilizing the mathematical model grounded in porous media theory and Darcy’s law, numerical simulations with COMSOL Multiphysics were conducted and construction parameters optimized. The proposed technology significantly advances safe and efficient coalbed methane recovery, benefiting coal mine safety and environmental sustainability.

Extensive studies have been reported on the application of ultrawideband (UWB) radar in rescue operations in the case of accidents. However, the identification of vital information in underground shelter spaces should be further improved to ensure successful rescue operations in the event of accidents. Therefore, in this study, a UWB radar vital-information recognition system suitable for drilling rescues was designed and developed. In addition to revealing the transmission attenuation of UWB radar waves in rock masses with different metamorphisms and thicknesses, the effect of vital-information recognition was verified, and effective ranges of vital-information recognition under different conditions were identified. The results indicate that the signal attenuation of the UWB radar wave increased with increasing rock mass thickness. The metamorphism of the rock mass was inversely proportional to the transmission attenuation of the UWB radar waves. Thus, the effective detection range for lignite and long-flame coal was 10 m, whereas that for lean coal was 15 m. When the thickness of the coal sample was

The problem of spontaneous combustion of coal left in the goaf poses a serious threat to coal mine safety, and the accurate positioning of its hidden ignition source is the key to effective governance. In order to accurately detect the location of the hidden ignition source of spontaneous combustion, combining the latest research results of scholars at home and abroad, the principles and applications of drilling detection method, infrared detection method, optical fiber temperature measurement method, thermocouple temperature measurement method, geological radar detection method, isotopic radon measurement method, and indicator gas detection method are reviewed. The above methods solve the problem of determining the dangerous area of spontaneous combustion, but are limited by their own technical characteristics and cannot fully adapt to the complex environment of the goaf, making it difficult to accurately detect the location of the ignition source. Compared with traditional methods, acoustic temperature measurement technology has the advantages of wide applicability, high reliability, and low economic investment. It has been successfully applied to the temperature field monitoring of grain storage warehouses. The porous medium characteristics of loose coal bodies in the goaf are similar to those of grain storage particles, based on which the idea of acoustic detection of hidden ignition sources in the goaf is proposed. We review and discuss the implementation methods and research progress of active acoustic wave temperature measurement method in the detection of hidden ignition sources in the goaf spontaneous combustion hazard area, focusing on the deficiencies in the current acoustic detection technology research related to acoustic feature recognition, acoustic attenuation, acoustic bending, temperature field reconstruction algorithm optimization, etc.

In response to the problem of blocked escape routes and difficulty in determining the location of trapped personnel caused by mining disasters and accidents, based on the principles and characteristics of ultra wideband (UWB) radar life information detection and position detection, combined with existing UWB radar detection technology, a UWB radar architecture suitable for borehole detection is proposed, key technical parameters are clarified, and a UWB radar life information detector is developed; we conducted UWB radar detection experiments under different detection distances, positions, target numbers, and weak body movements, and obtained detection spectrum features under three conditions. The experimental results show that the UWB radar life information detector can penetrate a 0.5 m brick wall and accurately locate personnel spatial information in complex terrain after disaster deformation. It can observe small-scale movements of personnel within a range of 4.0 m from radar echoes; when multiple human targets are within the same range of the radar transmitting and receiving antennas, and there are differences in their radial relative positions from the radar, the number of human targets can be determined based on the echo spectrum.

In order to investigate the influence mechanism of temperature on the permeability of loose coal body in the process of spontaneous combustion of residual coal in the gob, the mathematical model of the permeability of coal body under different temperature conditions was established by considering the effects of temperature-induced adsorption deformation, thermal expansion deformation, thermal fission deformation and sliding effect, etc., and the parameters of the single influencing factors of the mathematical model of the permeability were controlled by the method of controlling variables to investigate the influence mechanism of the temperature change on the permeability of the loose coal body. Based on the principle of physical similarity, an experimental platform for loose coal seepage was designed and constructed, and anthracite coal from Chengzhuang Mine in Shanxi Province was selected as the experimental object, and air was used as the seepage gas to simulate the underground environment, so that gas transport experiments were carried out in the loose coal body under different temperature conditions (40-100 ℃), different injection pressures (0.3-0.5 MPa), and different permeability pressures (0.04-0.08 kPa). The mechanism of the influence of temperature change on the permeability of the loose coal body was investigated by mutual verification of the experimental and modeling results. The results show that: the permeability of loose coal body increases exponentially with the increase of gas pressure gradient; under the condition of the same pressure gradient, the permeability decreases gradually with the increase of temperature; the influence of the temperature on the permeability is small when it is from 40 ℃ to 60 ℃, and the change of the permeability is not obvious, and the permeability starts to decrease after 60 ℃, and the decrease of the permeability is more significant when it is from 90 ℃ to 100 ℃; under the influence of the slippage effect, the increase of the injection pressure inhibits the permeability of the coal body. Under different osmotic pressure conditions (0.04-0.08 kPa), the model values of the permeability of the loose coal body and the experimental values of the seepage flow are in high agreement. With the increase of temperature, adsorption deformation has an inhibitory effect on the permeability of the loose coal body, thermal cracking deformation and the slipping effect have a promotional effect on the permeability of the loose coal body, and the effect of the deformation of the thermal expansion on the permeability of the loose coal body is weak. Temperature affects the permeability of loose coal body through the combined effect of adsorption deformation, thermal cracking deformation and sliding effect.

The flying-gangue hazard has long threatened the safety of personnel and mining equipment in steeply dipping/inclined coal seams. A flying gangue maybe produces a large number of “subgangues” after impacting on the longwall floor, it’s damage is sharply increased. Revealing the rupture response and fragmentation mechanism of the flying gangue under dynamic loading is one of the important contents to grasp the characteristics of dynamical damage for flying gangue hazard. This study was carried out through the combination of Split Hopkinson Pressure Bar test, model test and numerical simulation test. The results show: The failure mode of coal-rock under high-speed impact can be divided into three types: intact, single crack, and severe fragmentation. Fractal dimension D the coal specimen has a logarithmic relationship with the strain rate. Coal with lower uniaxial compression strength is more severely broken and has a larger fractal dimension D under the same strain rate conditions. The larger the coal size, the smaller the fractal dimension D is. The fractal dimension D of coal has a logarithmic relationship with strain rate regardless of whether the shape of the specimen is a disk or a cube. The “shape-rounded” phenomenon of the cube block is prone to appear during the movement. This phenomenon can be attributed to three parts: First, because the impact orientation between the block and slope or equipment is not strictly perpendicular compared with a drop test, the stress wave propagation within the specimen is dispersed to some extent during an impact. Second, because the block shape is not strictly regular, the stress is easily concentrated on a non-smooth surface. Finally, due to local shear failure in the contact area, a damaged area is formed. The corners of the flying-gangue are more susceptible to collision and direct loading, resulting in localized disintegration. This study provides a method for risk assessment and for determining the principles of protective systems in underground steep coal seams. In contrast, the flying-gangue involves material, geometry and other sources of uncertainty, stratification, fracture distribution and the degree of development by mining disturbance has a greater impact on the fractal characteristics of its crushing tends to be more complex. In the next step, the effect of the above factors on the crushing characteristics of the flying-gangue will be considered.

Intensive care unit-acquired weakness (ICU-AW) is prevalent in critical care, with limited treatment options. Certain microRNAs, like miR-542, are highly expressed in ICU-AW patients. This study investigates the regulatory role and mechanisms of miR-542 in ICU-AW and explores the clinical potential of miR-542 inhibitors. ICU-AW models were established in C57BL/6 mice through cecal ligation and puncture (CLP) and in mouse C2C12 myoblasts through TNF-α treatment. In vivo experiments demonstrated decreased muscle strength, muscle fiber atrophy, widened intercellular spaces, and increased miR-542-3p/5p expression in ICU-AW mice model. In vitro experiments indicated suppressed ATG5, ATG7 and LC3II/I, elevated MDA and ROS levels, decreased SOD levels, and reduced MMP in the model group. Similar to animal experiments, the expression of miR-542-3p/5p was upregulated. Gel electrophoresis explored the binding of polyethyleneimine/mesoporous silica nanoparticles (PEI/MMNs) to locked nucleic acid (LNA) miR-542 inhibitor (LNA-542). PEI/MMNs@LNA-542 with positive charge (3.03 ± 0.363 mV) and narrow size (206.94 ± 6.19 nm) were characterized. Immunofluorescence indicated significant internalization with no apparent cytotoxicity. Biological activity, examined through intraperitoneal injection, showed that PEI/MMNs@LNA-542 alleviated muscle strength decline, restored fiber damage, and recovered mitochondrial injury in mice. In conclusion, PEI/MMNs nanoparticles effectively delivered LNA-542, targeting ATG5 to inhibit autophagy and alleviate mitochondrial damage, thereby improving ICU-AW.

Spontaneous gas and coal combustion represent primary disasters threatening the safety of underground coal mines. Achieving the collaborative governance of the two disasters and enhancing the ability to prevent and mitigate mine disasters are technical challenges faced by high-gas/outburst mines. CO2 has become the primary choice for collaborative disaster governance because of its efficient control of the oxidation process of residual coal in goaf, enhanced coalbed methane (ECBM) recovery, and the goal of “2030 carbon peak and 2060 carbon neutralisation”. Therefore, this study adopted summary and engineering verification methods. Firstly, the basic physical and chemical properties of CO2 were analysed, and the three mechanisms of action of liquid CO2 for preventing coal spontaneous combustion (CSC), namely, “CO2 adsorbed and hindered oxidation reactions, absorbs ambient heat and reduces ambient temperature, and reduce the oxygen concentration in the goaf and inhibiting gas explosion”, and the six mechanisms of action of liquid CO2 ECBM recovery, namely, “pressure fracturing, low-temperature frostbite, physical extraction and chemical corrosion, low-viscosity permeability, phase change pressurisation, and competitive adsorption”, were summarised. Second, the effect was verified by the field application of liquid CO2 CSC emergency prevention and control at the Qinggangping Coal Mine and the engineering test of liquid CO2 ECBM recovery in the Shuanglong Coal Mine. Finally, based on the application status of liquid CO2 in coal mines, a new model of “liquid CO2 prevention and control of CSC and enhancing coalbed methane recovery comprehensive disaster reduction technology” is proposed. The results of the emergency prevention and control of liquid CO2 CSC show that CO2 sinking drives CH4 out of the roadway, avoids the accumulation of CH4 near the fire area, and achieves explosion suppression. The concentrations of C2H2 and C2H4 in the mine decreased rapidly to 0. No open fire or severe combustion occurred in the mine, and the fire area was effectively controlled. After the ventilation of the mine was restored, the isolated and closed 42108 working face was injected with liquid CO2 again. The CO concentration of the inlet and return air along the channel gradually decreased to zero, and the fire area of the working face was further controlled. The engineering test of liquid CO2-ECBM recovery showed that the dominant seepage range was 1215 m from the injection hole, and the dominant diffusion range was 2530 m from the injection hole. The average CH4 flow rate in the field extraction test was more than three times that of the original area. Through two field cases, long-distance liquid CO2 prevention and control of CSC and an ECBM recovery technical framework were proposed, which are of great significance for further improving mine disaster prevention and mitigation.

This study focuses on the efficiency of liquid CO2 (LCO2) displacing CH4 in the coal under optimal Ti and Pi. The objective is to study the influence on the efficiency of LCO2 injection to displace CH4 under the different temperature (Ti) and pressure (Pi). Thereafter, an in-situ test is conducted on LCO2 injecting to enhance coalbed methane (LCO2-ECBM) in a high-gas coalbed. Results showed that low temperature inhibited the movement activity of CO2/CH4 in coal, a significant delayed effect is exhibited during CO2 displacing CH4, and the maximum displacement efficiency (ηmax) is only 56.02 %. The competitive-adsorption effect of CO2/CH4 intensified, and ηmax increased to 84.13 % as Ti gradually increased. The CH4 desorption rate and migration dynamics in the coal intensified as Pi increased, resulting in a significant increase in efficiency, and ηmax reached 92.87 %. At 30 °C, where CH4 is present in the coal, an appropriate increase in Pi caused the maximum replacement ratio to decrease from 1.60:1 to 0.40:1, indicating a higher efficiency. An In-situ test of LCO2-ECBM showed that the concentration and flow rate of methane increased by nearly three times, and the CBM extraction time and borehole layout number have been shortened by one-third and half, respectively.

The accurate determination of coal temperature in the hidden spaces such as goaf has always been a worldwide problem that needs to be solved urgently. The study of acoustic temperature measurement technology is of great practical significance for a fast and accurate detection of loose coal temperature, and the scientific and accurate construction of the mapping relationship between sound velocity and coal temperature is the key to acoustic coal temperature measurement. In this paper, considering the influence of the characteristic parameters of spontaneous combustion process of loose coal on sound wave propagation, a mapping model of sound velocity and coal temperature in the quasi-porous media of loose coal was established. An acoustic temperature measurement experimental system for loose coal was designed and built. By conducting the acoustic temperature measurement tests for the loose coal with various particle sizes (0.6～1.5, 1～3, 3～5 cm), the effect of gas composition and concentration on sound propagation during the low-temperature oxidation stage (30～50 ℃) of coal samples with different particle sizes was studied, and the equivalent path conversion factor λ was determined. Based on the relationship between the measured sound velocity and the equivalent path conversion factor, the medium correction coefficient φ of the gas component was proposed and determined, and the feasibility of the sound-temperature mapping relationship model was verified. The results show that the acoustic wave propagation path of loose coal is affected by the characteristic parameters of coal particle size, temperature and the change of gas component medium, etc. A mapping model of sound velocity and coal temperature was established. At normal temperature, the propagation path of sound waves in the quasi-porous medium of loose coal is mainly affected by the pores between the coal particles. The equivalent path conversion factor λ of sound waves is 1.426 1, 1.371 1 and 1.315 2, respectively, when the coal particle size is 0.6～1.5, 1～3, 3～5 cm, which is negatively correlated with the particle size. The influence of coal temperature on acoustic wave propagation is manifested by the change of gas component medium in the process of spontaneous combustion of coal, which verifies the feasibility of the mapping relationship between sound velocity and coal temperature. The error rate between the inversion model and the experimental coal temperature is 0～6.46%, and the average coal temperature error is 2.52 ℃, which can reflect the coal body temperature well.

Close-hole roof-cutting technology (CHRCT, also called “dense drilling”) has been widely applied in coal mines due to its economic and safety benefits. Inappropriate cutting parameters and support schemes can lead to dynamic pressure disturbances in self-forming roadways with thick and hard roofs. Moreover, fully characterizing the procedure and process of self-forming roadways using CHRCT in the field is difficult, resulting in unconvincing results. Therefore, this study aims to fill the gaps in theoretical knowledge and methodology. First, the dynamic pressure characteristics of the self-forming roadway using CHRCT were investigated, and the dynamic pressure types of the roadway were classified. There are three main types: roof cut off along the coal wall side of, severe deformation, and overhanging roof of a roadway after the second working face mining. The effects of different hole parameters (inclination angle, depth and spacing) on the roof cutting to form a roadway were also investigated. The optimal hole inclination, depth and spacing of 15°, 8 m, and 200 mm were determined through a series of experiments. Then, three support schemes embedded in the roadway were compared in terms of stress evolution, bolt and cable axial forces, roof displacement, and structure. Finally, this study proposes a dynamic pressure mitigation strategy through the optimization of parameters for close-hole roof-cutting and support schemes, monitoring and controlling ground pressure in roadways, and taking auxiliary measures for pressure relief. The results show that this strategy can effectively eliminate the dynamic pressure of the roadway and meet the stability requirements of the full mining cycle. This paper presents a methodology for analysing CHRCT via numerical simulation. Moreover, this approach is of great theoretical and practical importance for dynamic pressure control for self-forming roadways using CHRCT in thin coal seams with thick and hard roofs.

Liquid CO2 enhancing coalbed methane recovery (CO2-ECBM) is an effective and intrinsically reliable gas drainage technology. Injection of liquid CO2 into coal seam has the dual effect of increasing the permeability of the coal and rock and strengthening the recovery of gas, which is manifested primarily as “pressure cracking, low temperature frostbite, physical extraction and chemical corrosion, phase change pressurization, low viscosity permeability, competitive adsorption”. In this paper, the acidification and corrosion of CO2-H2O-coal was studied in physical and chemical extraction by experimental test and comparative analysis. The liquid CO2 acidification reference group and the variable group experiment were designed. On the basis of the pH value of the aqueous solution, the content of major elements and minerals in coal, the minerals involved in chemical reaction, and their specific gravity were deduced. Variation in pore volume, specific surface area, and pore fractal characteristics were quantitatively and qualitatively analyzed. The experimental results show that the higher the pressure, the higher the content of carbonic acid dissolved in water and the amount of H+ ionized by carbonic acid. The longer the reaction time, the greater the mineral content involved in the chemical reaction, and the H+ in the water sample is consumed in large quantities. The elements of Na, K, Ca, Mg, Al, Si, S, P, and Ti decreased with increasing pressure, and the maximum decreases were 0.004 %, 0.024 %, 1.095 %, 0.028 %, 0.220 %, 0.304 %, 0.006 %, 0.003 % and 0.029 %, respectively. The decrease in Ca element was the largest, indicating that Ca-bearing minerals participate in the reaction. Calcite, kaolinite, and illite were the main minerals involved in the chemical reaction of CO2-H2O-coal. The pores (d > 100 nm) and transition pores (10 < d < 100 nm) in the sample were further developed, and the pore volume increased significantly, forming a good gas migration channel. In addition, the number of new micropores (2 < d < 10 nm) increases, the specific surface area increases significantly, and the complexity of the pores increases, forming a good reservoir.

In order to explore the distribution characteristics of “three zones” of spontaneous combustion in goaf under different ventilation modes, based on the engineering background of “two into one” ventilation mode at 1532 (1) working face of Gubei Mine, and based on airflow control equation, concentration component equation and energy equation, by using the Fluent numerical simulation method, the multi-physical coupling numerical model of coal spontaneous combustion and the real-time dynamic advance model of working face are established, and the distribution characteristics of “three zones” of spontaneous combustion in goaf by the “110 construction method” under three ventilation modes are simulated. The results show that with the continuous advance of the working face, under the conditions of ventilation mode 1 (air intake from the machine side and gob-side entry retaining, return air along the return air lane) and ventilation mode 2 (air intake from the machine side and along the return lane, and return air in gob-side entry retaining), the oxidation spontaneous combustion belt in the goaf is evenly distributed in the side of the belt machine, the middle of the working face and the side of the lane, and the oxygen concentration distribution is not much different. About 50 days after mining, the highest temperature appeared in the deep side of the transportation lane, and the temperature at this position did not increase with the continuous advance of the working face. Under the condition of ventilation mode 3 (air intake in gob-side entry retaining and return air lane, and air return at the side of the machine lane), the oxidation spontaneous combustion belt at the side of the goaf retaining roadway becomes 2-4 times wider, the middle of the working face and the side of the belt conveyor become obviously narrow, the oxygen volume fraction at the side of the belt conveyor in the goaf is lower, the oxygen concentration at the side of the belt conveyor is higher, and the air leakage increases significantly. The high temperature location of goaf mainly appears in the side of the stop line of 1532(1) working face, and the temperature of goaf here is the highest after 50 days of working face. In summary, combined with the actual situation of the site, the width and location of the oxidation spontaneous combustion belt are analyzed, and the ventilation mode 3 is finally determined to be more conducive to preventing the occurrence of coal spontaneous combustion, which provides theoretical guidance for the prevention of coal spontaneous combustion in mines.

ObjectiveTo provide a scientific basis for optimizing the registration and regulation， disease/medical states with a high clinical need for specific whole-nutrient foods for special medical purposes （FSMP-S） were identified.MethodsA core outcome set construction method was used in this study. A systematic review was conducted to determine the list of diseases/medical states that could be supported by FSMP-S. Then， a list of diseases/medical states with high clinical demand for FSMP-S was selected through the Delphi method and face-to-face consensus meetings， and optimization suggestions for classifying the FSMP-S were proposed.ResultsA total of 27 studies were identified， and 103 diseases/medical states with FSMP-S intervention were obtained from 5，984 papers in Chinese and English. Forty-seven physicians and dietitians from 3A hospitals participated in two rounds of Delphi surveys， after which 23 diseases/medical states were recognized as having high clinical demand for FSMP-S. The consensus meeting narrowed the scope of the FSMP-S to a high clinical need of 11 diseases/medical states. Finally， a “1+1” optimization strategy was proposed to add nutritional metabolic characteristics to the classification method for FSMP-S.ConclusionThe “1+1” strategy could optimize the classification of FSMP-S from the perspective of clinical application requirements； however， its feasibility remains undemonstrated.

In order to overcome the difficulty of gas mining when coal mining depth increased, the adsorption and diffusion laws of CO2 molecules at different temperatures and pressures were simulated by using the simulation software Materials Studio; the relationship between CO2 mean square displacement and time was simulated based on molecular dynamics. The results showed that in the isothermal adsorption curves of 15 ℃, 25 ℃, 30 ℃ and 35 ℃, the adsorption capacity of CO2 decreased gradually when temperature increased. It showed that CO2 was conducive to geological storage at low temperatures; the values of self-diffusion coefficient, corrected diffusion coefficient and transfer diffusion coefficient of CO2 in coal increased when temperature and pressure increased. The maximum value was reached at 35 ℃ and 3.5 MPa.

As of October 2022, the United Nations Office on Drugs and Crime (UNODC) Early Warning Advisory (EWA) has monitored over 1 150 new psychoactive substances (NPS) that had appeared in 137 countries and territories, including 76 substances that were notified for the first time in 2022. The increasing popularity of NPS has become a policy challenge and a major international concern, and poses potential risks for public health. Ketamine and ketamine analogues belong to β-keto-arylcyclohexylamines, which are classified into dissociative NPS due to their “dissociative anesthetic” effect. According to the monitoring data of the National Narcotics Laboratory, as of August 2022, ten ketamine structural analogues have been detected in China, including 2-(2-chlorophenyl)-2-(ethylamino) cyclohexan-1-one (NENK), 2-(3-methoxyphenyl)-2-(ethylamino) cyclohexan-1-one (MXE), 2-phenyl-2-(methylamino) cyclohexan-1-one (DCK), and 2-(2-fluorophenyl)-2-(methylamino)cyclohexan-1-one (2-FDCK), 2-(ethylamino)-2-phenylcyclohexan-1-one (2-oxo-PCE), 2-(methylamino)-2-(2-methylphenyl)cyclohexan-1-one (2-MDCK), 2-(ethylamino)-2-(2-fluorophenyl)cyclohexan-1-one (2-FXE), 2-(2-bromophenyl)-2-(methylamino)cyclohexan-1-one (2-BDCK), and 2-(ethylamino)-2-(thiophen-2-yl)cyclohexan-1-one (tiletamine), and 2-(ethylamino)-2-(2-methylphenyl)cyclohexan-1-one (deoxymethoxetamine). According to the structures, these compounds can be seen as structural analogues of ketamine with benzene ring replaced by fluorine, bromine, methyl and methoxy groups, or with methyl group on the nitrogen atom replaced by ethyl group, or with benzene ring replaced by furan group. NENK, MXE, DCK and 2-FDCK have already been included in the annexes of the law in China, while 2-oxo-PCE, 2-MDCK, 2-FXE, 2-BDCK, and tiletamine have not been listed in the regulation. In order to evade the supervision of the law, new types of ketamine analogues have been continuously produced and offered for sale on the NPS market. These emerging new compounds have posed a great challenge to the testing and identification ability of forensic science laboratories around the world. The knowledge of MS fragmentation pathway characteristics of known structure NPS is essential for the structure elucidation of new types of NPS. In order to investigate the mass fragmentation characteristics of ketamine analogues, NENK, MXE, DCK, 2-FDCK, 2-oxo-PCE, 2-MDCK, 2-FXE, 2-BDCK, and tiletamine were analyzed using gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap-MS) and ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-QTOF-MS). High-resolution mass spectra were obtained by electron impact (EI) and electrospray ionization collision-induced dissociation (ESI-CID), the structures and fragmentation pathways of main ions were deduced. The product ions of ketamine analogues were mainly formed by the loss of CO, C2H5·, C3H7·, C4H9·, C5H11·/C6H13· in EI mode, and were mainly formed by the loss of H2O, CH3NH2/C2H5NH2, CO, C4H6, C2H4O in ESI-CID mode. The ketamine analogues distinguishing features were summarized by investigating the high-resolution mass spectrometric characteristics, which can provide a reference for the identification of new ketamine analogues with similar chemical structures.

The acoustic temperature measurement method has a broad application prospect due to its advantages of high precision, non-contact, etc. It is expected to become a new method for hidden fire source detection in mines. The acoustic time of flight (TOF) can directly affect the accuracy of acoustic temperature measurement. We proposed a quadratic correlation-based phase transform weighting (PHAT-β) algorithm for estimating the time delay of the acoustic temperature measurement of a loose coal. Validation was performed using an independently built experimental system for acoustic temperature measurement of loose coals under multi-factor coupling. The results show that the PHAT-β algorithm estimated acoustic TOF values closest to the reference line as the sound travelling distance increased. The results of coal temperature inversion experiments show that the absolute error of the PHAT-β algorithm never exceeds 1 °C, with a maximum value of 0.862 °C. Using the ROTH weighted error maximum, when the particle of the coal samples is 3.0–5.0 cm, the absolute error maximum is 4.896 °C, which is a difference of 3.693 °C from the error minimum of 1.203 °C in this particle size interval. The accuracy of six algorithms was ranked as PHAT-β > GCC > PHAT > SCOT > HB > ROTH, further validating the accuracy and reliability of the PHAT-β algorithm.

The accurate determination of coal temperature in hidden space such as goaf has always been a worldwide problem that needs to be solved. The research of coal temperature prediction model has important practical significance for the accurate detection of loose coal temperature. Based on the coal natural ignition experiment and coal spontaneous combustion gas characterization index as the initial data set GRU neurons are used to mine the nonlinear relationship between the index gas and temperature, and the GRU model parameters are optimized by PSO to obtain the predicted value of coal body temperature. The results show that the predicted MAE value of the PSO-GRU model is 1.37 °C, 6.51 °C, 11.40 °C, 15.90 °C, 20.20 °C lower than that of the PSO-SVM, PSO-BP, BP, RF and SVM prediction models respectively. The RMSE value decreased by 0.45 °C, 4.44 °C, 10.33 °C, 15.71 °C and 24.24 °C respectively. The judgment coefficient R2 on the test set and the training set of the PSO-GRU model is 0.99, and the generalization, prediction accuracy and robustness are all good. The experimental results show that the inversion temperature error of the model is within the range of 3.87 %, the maximum temperature difference is 5.69 °C, and the average temperature difference is 2.83 °C, which can meet the accuracy requirements of the field temperature measurement.

ObjectiveTo investigate and analyze the standardized management and clinical application of food for special medical purposes （FSMP） in secondary and above medical institutions of China.MethodsIn the form of online questionnaire， the medical institutions in 34 provinces / municipalities were sampled through the platforms of Sichuan Provincial Clinical Nutrition Quality Control Center and the Clinical Nutrition Discipline Alliance of West China Hospital.ResultsA total of 300 valid questionnaires were collected. In terms of FSMP management： 24.3% of medical institutions set up FSMP management committee； 64.3% of medical institutions formulated the catalogue of FSMP. Medical institutions with FSMP warehouses and FSMP preparation rooms accounted for 47.3% and 50.7%， respectively. 40.7% of medical institutions incorporated FSMP into information management； 43.3% of medical institutions charged unified coding fees. For clinical application of FSMP： 94% of medical institutions required nutrition risk screening before FSMP prescription； 84.7% of medical institutions required qualified prescribers； nearly 90% of medical institutions prescribed FSMP by nutritionists； 67.3% of medical institutions required the superior clinicians/ nutritionists to review the FSMP prescription before implementation. The adverse reaction of FSMP use was monitored in all 300 medical institutions， and only 30.7% reported the monitoring data of the adverse reactions to the provincial / municipal clinical nutrition quality control center.ConclusionThe government should strengthen the construction of specialized fee catalogue and the unification of prescription qualification training； medical institutions at all levels， especially hospitals in the western region and secondary hospitals nationwide， should set up FSMP management committee as soon as possible， and integrate FSMP into the hospital information system. The clinical nutrition discipline should strengthen the formulation of clinical norms， detailed rules for the application of FSMP and supervision system. Safety monitoring and effectiveness evaluation should be strengthened so as to maximize the value of nutritional treatment of FSMP.

Epilepsy is a common neurological disease in clinic. Epilepsy caused by structural causes can be cured by surgery, which has been the focus of attention in the field of epilepsy surgery. With the development of gene sequencing technology, more and more studies have found that structural etiology may be caused by somatic mutations of genes. In this paper, somatic mutation⁃related pathogenic genes of four common pathological types of epilepsy surgery, including malformation of cortical development (MCD), long⁃term epilepsy associated tumor (LEAT), hippocampal sclerosis (HS) and hypothalamic hamartoma (HH), were reviewed, and their effects on surgical protocol formulation and prognosis were reviewed, in order to provide a new idea for the treatment of epilepsy.

The CO2 enhanced coal bed methane recovery technology provides an excellent way to mitigate the greenhouse effect and energy crisis. The features and mechanism of CO2/CH4 competitive adsorption in the coal rock matrix have a critical impact on the production of CBM. For CO2/CH4 competitive adsorption process components and pressure changes, a multi-component gases competitive adsorption experiment was carried out with CO2 and CH4 binary gases as the study objects, and a multi-component adsorption model was developed by the expanded Langmuir equation. Based on the principles of molecular dynamics and thermodynamics, important parameters such as the average free range of gas molecules and adsorption potential are introduced to explain the competitive adsorption behavior from multiple perspectives and explore the competitive adsorption law of CH4 and CO2 under multiple component conditions, so as to provide some theoretical basis and field guidance for improving the extraction effect of CH4 in coal seams. The results show that: Under two critical conditions (100%CO2 +0%CH4 and 0%CO2 +100%CH4), the Langmuir volumes of CO2 for HN 1/3 coking coal and HL weakly caking coal respectively are 2.21 and 3.01 times higher than those of CH4; the overall adsorption capacity of binary gas is in between the adsorption capacities of both critical conditions and increases with increasing CO2 concentration in the gas source ratio; using E-L equation for binary gas component partitioning, the CH4 partition curves were all below CO2, the concentration of free-phase CH4 was always higher than that in the adsorbed phase, and coal samples had stronger adsorption ability for CO2 than CH4. CO2 has a stronger adsorption potential at the surface for HL weakly caking coal. CH4 has a slightly stronger adsorption potential at the surface for HN 1/3 coking coal. The higher coalification degree of the coal sample, the stronger the adsorption ability for CH4 and the weaker the adsorption ability for CO2. The slope of the overall adsorption curve of multi-component gases is analogous to the slope of the component with a high ratio of gas or strong adsorption capacity; the capacity of one-component adsorption for dual gas is closely related to the partial pressure of the free-phase gas and the separation factor α21. When the concentration ratio of CH4/CO2 in free phase is y2/y1 =α21, the concentration of both gases in adsorption phase is 50%, and α21 correlation is weakened, then the free phase gas partial pressure is dominant and there is a threshold value makes CH4 and CO2 adsorption capacity equal; when y2/y1 α21, the coal preferentially adsorbs CH4 in the binary gas.

In order to reveal the influence of air leakage on oxygen concentration in goafs of fully mechanized caving mining with a shallow buried and high mining height, the air leakage of No.122108 working face in Caojiatan coal mine in different seasons was tested by the SF6 tracer gas test method. Based on the result of the air leakage test, the “three zones” of spontaneous combustion in the goaf were simulated using Ansys Fluent fluid dynamics software, and the simulated result was compared with that of the field test. The result shows that the vertical air leakage of the working face is serious, the wind speed is high, and the air leakage rate is up to 86.96%. The air leakage rate is higher in winter and lower in summer. The air leakage intensity decreases from the air inlet side to the air return side through the middle of the goaf. The range of the oxidation heating zone of the goaf is 98–245 m on the air inlet side and 33–96 m on the air return side. The numerical simulation result is well consistent with the field test data. The research conclusion can guide fire prevention and the extinguishing of No.122108 working face and lay a foundation for the prevention and control of spontaneous fire in goafs of fully mechanized caving mining with a shallow buried and high mining height.

Objective To investigate the association between white matter hyperintensity (WMH), aspirin therapy and cerebral microbleeds (CMBs), and to screen risk factors for CMBs and severity of CMBs. Methods Total 2654 patients with ischemic cerebrovascular disease were admitted to Department of Neurology in Beijing Chao⁃Yang Hospital, Capital Medical University from June 2016 to February 2021. Systolic blood pressure (SBP), diastolic blood pressure (DBP), aspirin therapy, time of aspirin therapy, high⁃density lipoprotein cholesterol (HDL⁃C) and low⁃density lipoprotein cholesterol (LDL⁃C) of the serum, glycated hemoglobin (HbA1c), homocysteine (Hcy), fibrinogen (FIB) and D⁃dimer of plasma were collected within 24 h of admission. MRI was used to evaluate the severity of WMH by Fazekas score and identify the number of CMBs by Microbleed Anatomical Rating Scale (MARS). Univariate and multivariate stepwise Logistic regression analyses were used to screen the related risk factors for CMBs and its severity. Results Total 2654 patients were divided into control group (n=1315), mild (n=461), moderate (n=440) and severe (n=438) WMH groups by Fazekas score. There was statistically significant difference in age (H=353.837, P=0.000), history of hypertension (χ2=79.818, P=0.000), coronary heart disease (χ2=56.768, P=0.000) and diabetes (χ2=8.936, P=0.030), SBP at admission (H=47.979, P=0.000), aspirin therapy (χ2=161.576, P=0.000), time of aspirin therapy (H=4.766, P=0.000), serum LDL⁃C (H=16.533, P=0.002), plasma HbA1c (H=22.127, P=0.000) and Hcy (H=83.558, P=0.002), proportion of CMBs (χ2=642.054, P=0.000) among groups. Logistic regression analysis showed that DBP at admission (OR=1.017, 95%CI: 1.007-1.026, P=0.001; OR=1.020, 95%CI: 1.011-1.029, P=0.000) and Fazekas score (OR=1.673, 95%CI: 1.590-1.761, P=0.000; OR=1.754, 95%CI: 1.669-1.844, P=0.000) were risk factors for CMBs and its severity. Serum LDL⁃C was a protective factor for CMBs and its severity (OR=0.856, 95%CI: 0.765-0.957, P=0.006; OR=0.860, 95%CI: 0.774-0.956, P=0.005). Aspirin therapy and time of aspirin therapy were not significantly correlated with CMBs and its severity. Conclusions Severity of WMH (Fazekas score) was a risk factor for CMBs and its severity.

The functional group structures of coal molecules are one of the most important factors affecting spontaneous combustion. However, it is difficult to determine the exact effects of such structures. Extraction technology is able to modify the functional groups in coal as a means of inhibiting spontaneous combustion reactions. The present work extracted coal from the Caojiatan mine in northern Shaanxi, China, with various solvents. The extraction effectiveness of these solvents was found to decrease in the order of dioctyl sulfosuccinate (AOT) > water > n-hexane > cyclohexane + AOT + ethanol > cyclohexane > ethanol > methanol. With the exception of the AOT, the concentration of functional groups in the extracted coal was decreased compared with that in a control specimen extracted using only water. Ethanol, n-hexane, and methanol provided the optimal extraction efficiencies in terms of capturing coal molecules with aromatic structures, aliphatic structures, and oxygen-containing groups, respectively. The results of this work are expected to assist in future research concerning the extraction of coal molecules with specific functional groups. This work also suggests new approaches to the active prevention and control of spontaneous combustion during the mining, storage, and transportation of coal.

The aim of this paper is to analyze the deformation-failure degree and microstructure variations in coal under the cryogenic-freezing effect of liquid CO2. In this paper, X-ray CT scanning technology is adopted to measure the microscopic-morphological parameters of coal. Drawing support from the image processing and three-dimensional (3D) visualization functions of Avizo software, 3D spatial structure variation rules, as well as the deformation and permeability parameters, are quantitatively calculated. Under the effect of LCO2 cryogenic freezing, the macroscopic mechanical properties and deformation-failure degree of coal are thoroughly analyzed. The results show that fracture-scale parameters of treated coal are significantly increased, resulting in spatial structure parameters including the coal plug total volume (Vt), fracture network volume (V0), and proportion of fracture network (μ0) to increase by 17.11%, 56.57%, and 55.59%, respectively. A comparison analysis indicates that the coverage area of a single value function from the percolation theoretical model for treated coal plugs becomes larger, and its percolation curves are more intensive; the quantitative coal permeability coefficients are increased to more than 40% on average, which further proves that the permeability of coal by using LCO2 cryogenic freezing is significantly improved. Under the same uniaxial stress loading rate, the peak stress threshold value required by treated coal in the compaction and elastoplastic deformation stage is decreased. The corresponding output acoustic emission energy is apparently increased, owing to the increased brittleness of coal, and deformation failure of coal occurs more easily. Simultaneously, the fracture network and matrix surface of treated coal are more complex, and the corresponding fractal characteristic is obvious. It could be thus concluded that the coal plugs have deformation-failure changes under cryogenic freezing by using LCO2, increasing the proportion of coal microstructure and enhancing coal permeability. Therefore, the capability of gas migration through the coal microstructure becomes easier, which is favorable for coalbed methane recovery.

Since the Harvard Brain Death Criteria was published in 1968, many guidelines and diagnostic procedures of Brain Death/Death by Neurologic Criteria (BD/DNC) have been published throughout the world, and these determination criteria have been constantly revised and updated. The World Brain Death Project published the "Determination of Brain Death/Death by Neurologic Criteria" in 2020 to unify clinical practice across countries and improve the rigorousness of BD/DNC determination. This article analyzes and interprets these "Determination of Brain Death/Death by Neurologic Criteria" (version 2020) to clarify the concept of BD/DNC, the minimum clinical criteria for Determination of BD/DNC, ancillary testing, and the pediatric/neonatal BD/DNC, and to compare with the current practical guidance for determination of brain death in China, and analyze the differences between China and foreign countries, so as to provide reference for medical personnel in related professions in China. doi:10.3969/j.issn.1672⁃6731.2021.04.003

Objective To explore the prevalence, influencing factors, and clinical and imaging features of cervicocerebral artery dissection (CAD) in young patients with ischemic stroke. Methods A total of 242 young patients with first ever ischemic stroke were included in this study from October 2016 to September 2020. Thirty⁃two patients with CAD were included in the CAD group, and 210 patients without CAD were included as controls. We collected the clinical and imaging data of all the patients. Univariate and multivariate Logistic regression analysis were used to screen the influencing factors of young ischemic stroke patients caused by CAD. And we analyzed imaging characteristics of CAD in different locations. Results Among the 242 young patients with ischemic stroke, 32 (13.22%) patients were due to CAD. Compared with the control group, the CAD group had younger onset age (t=⁃3.480, P=0.001), more inducible events (infection and neck movement) before the onset of cerebral infarction (t=8.796, P=0.003), and higher incidence of headache or neck pain (t=17.466, P=0.000) and posterior circulation infarction (t=22.705, P=0.000). Multivariate Logistic regression analysis showed that older age (OR=0.920, 95%CI:0.853-0.992; P=0.030), the infarction located in the anterior circulation (OR=0.145, 95%CI:0.059-0.356;P=0.000) were protective factors for ischemic stroke due to CAD, while head and neck pain (OR=5.428, 95%CI:1.653-17.824; P=0.005) was risk factor for ischemic stroke due to CAD. The artery dissection lesions were located in anterior circulation in 11 (34.37%) patients with CAD, including 9 cases of extracranial carotid artery, one case of anterior cerebral artery, and one case of middle cerebral artery, while 21 (65.63%) patients' artery dissection lesions were located in the posterior circulation, including 10 cases of extracranial vertebral artery dissection (2 patients with bilateral lesions), 6 cases of intracranial segment, 4 cases with both intracranial and extracranial segment involvement, and one case with posterior inferior cerebellar artery dissection. After discharge, the follow⁃up imaging examination of 9 CAD patients showed that 6 patients had varying degrees of recovery of the arterial lumen and the rest 3 patients had no change. Conclusions CAD is a common cause of cerebral infarction in young people, and younger age, posterior circulation infarction and head and neck pain are risk factors for CAD. doi：10.3969/j.issn.1672⁃6731.2021.04.011

Substance use disorders (SUD) and drug addiction are major threats to public health, impacting not only the millions of individuals struggling with SUD, but also surrounding families and communities. One of the seminal challenges in treating and studying addiction in human populations is the high prevalence of co-morbid conditions, including an increased risk of contracting a human immunodeficiency virus (HIV) infection. Of the ~15 million people who inject drugs globally, 17% are persons with HIV. Conversely, HIV is a risk factor for SUD because chronic pain syndromes, often encountered in persons with HIV, can lead to an increased use of opioid pain medications that in turn can increase the risk for opioid addiction. We hypothesize that SUD and HIV exert shared effects on brain cell types, including adaptations related to neuroplasticity, neurodegeneration, and neuroinflammation. Basic research is needed to refine our understanding of these affected cell types and adaptations. Studying the effects of SUD in the context of HIV at the single-cell level represents a compelling strategy to understand the reciprocal interactions among both conditions, made feasible by the availability of large, extensively-phenotyped human brain tissue collections that have been amassed by the Neuro-HIV research community. In addition, sophisticated animal models that have been developed for both conditions provide a means to precisely evaluate specific exposures and stages of disease. We propose that single-cell genomics is a uniquely powerful technology to characterize the effects of SUD and HIV in the brain, integrating data from human cohorts and animal models. We have formed the Single-Cell Opioid Responses in the Context of HIV (SCORCH) consortium to carry out this strategy.

To address the problems of edge blur and weak detail resolution when fusing infrared and visible images with traditional methods, a novel image fusion approach based on fast super-resolution convolutional neural network and anisotropic diffusion is proposed. The proposed method first employs super-resolution reconstruction based on fast convolutional neural networks to get high-resolution infrared images. Second, the visible and high-resolution infrared images are anisotropically diffused to obtain the corresponding base layers and detail layers. Next, the fusion of the detail layer is performed through Karhunen-Loeve transform, and an adaptive saliency module is constructed to fuse the base layer. Finally, the fusion result is obtained by applying linear reconstruction on the fused detail layer and base layer. Compared with other algorithms, the experimental results show that the proposed algorithm not only has better objective evaluation indexes but also can better retain the details of the original image.

Canine parvovirus type-2 (CPV-2) causes acute infectious diseases in puppies, which show high morbidity and mortality. Better effect of vaccination against these diseases could be achieved with deeper knowledge of CPV-2 genotype dissemination and mutation history. This study investigated CPV-2–positive samples collected recently over a wide region of China.

Canine parvovirus (CPV) disease is one of the most threatening to domestic and wild dogs.

Objective To study the mechanism of rib fracture caused by landing on different parts of the trunk using finite element method, and to provide some new techniques and new ideas for the reconstruction of the whole process of falls from height. Methods The finite element method was used to study the rib fracture of human security model THUMS4.0 caused by landing on different parts of the trunk. Then the model was compared with actual cases and the mechanism of rib fracture caused by falls from height was analyzed from a biomechanical point of view. Results There were some differences in the stress and strain distribution as well as the rib fracture sites when different parts touched the ground. Ribs on both sides of the body were fractured when the front of the trunk touched the ground, and the fractures were mainly located in the junction of the ribs and costal cartilage and the midaxillary line area. When the right anterior part of the trunk touched the ground, rib fracture occurred first on the side that touched the ground, and rib fractures were mainly located in the area from the right midaxillary line to the posterior axillary line, and junction of ribs on both sides and costal cartilage. When the back of the trunk touched the ground, the fracture sites were mainly located on the back of the ribs on both sides. When the right posterior part of the trunk touched the ground, multiple rib fractures were likely to occur in the parts that touched the ground. The plastic strains were mainly concentrated at the fracture sites, while the von Mises stresses were not only concentrated at the fracture sites, but also at other sites. Conclusion There are some differences in rib fracture location sites and injury mechanisms when different parts of the trunk touch the ground.

A computational fluid dynamics model is established to investigate the behavior of fire smoke spreading in L-shaped utility tunnels with small curvature radii (R). The fire evolution process for tunnels with R = 0–25 m and critical ventilation velocities (V) of 0.5–3.0 m/s is analyzed, and the Richardson number (Ri) is introduced to determine the critical value for the development of fire smoke back-layering. The results show that R and V strongly influence the fire-induced spatiotemporal evolution characteristics in such utility tunnels. Smaller R or higher V are associated with stronger centrifugal forces, which causes the smoke to move downstream of the fire source and increases the instability and risk. The non-dimensional smoke back-layering length shows a linear relationship with ln(Q*/V*3), where Q* is the dimensionless fire source power. Integrated with the V and smoke force in a curved tunnel, the critical Ri value is found to be 6.34 for R = 10 m. This means that smoke back-layering will appear when Ri > 6.34 and disappear when Ri