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In the present study, a numerical simulation method was adopted in order to examine the characteristics of dust dispersion during continuous dust release periods (CRP) and stop dust release periods (SRP). The purpose was to analyze the dust distributions and migration actions around road-header drivers in excavation roadways, and then determine effective dust control measures for underground coal mines. This study’s simulation results showed that the dust concentrations continuously increased, and then gradually reached a stability level during the CRP. During that time, the locations of the drivers were always at the intersection of the original migration dust and the backflow dust, and the drivers were invaded by these two strands dust. However, during the SRP, the dust concentrations gradually decreased under the actions of the roadway ventilation. Besides, obvious backflow phenomena were observed around the road-header during the SRP. The locations of the drivers were still within the backflow paths of the high dust concentrations. At the present time, dust separation and extraction systems have been implemented in coal mines, including vacuuming and air knife devices, which are designed to control the dust around the road-header drivers. The field applications of these systems were conducted in the 26 mechanized excavation faces of the Zhangcun Coal Mine. The results revealed that the use of these dust removal systems could effectively reduce the dust concentrations around the road-header drivers. In the present study, the dust removal rates during the CRP and SRP were determined to reach up to 88.7% and 94.6%, respectively. Therefore, the results of this research study provided effective theoretical guidance of the characteristics of dust distributions in coal mines, and introduced effective control methods for the hazardous dust concentrations around road-header drivers during the excavation process.

The ventilations of pressure cylinders is a widely used practice in coal mine roadways in China. It has been determined that the velocities of the ventilations will directly affect the diffusion of the dust particles which reduce the visibility of road-header drivers, and also tend to slowdown operating efficiency. In this study, a CFD-DPM method was adopted in order to examine the airflow flow and dust pollution behaviors in coal mine roadways under various ventilation velocities. The results showed that airflow fields could be divided into disordered regions of airflow flow fast and chaos; recirculation regions, where there were dust backflow; and stable regions, from the heading faces to the exits of the coal mine roadways. The airflow were observed to carry the dust particles along the roadway wall away from the pressure cylinders from the disordered regions into the recirculation regions due to the blocks caused by the road-headers. It was observed that the dust migration had slowed down in the areas behind the road-headers due to the sudden decreases in the airflow velocities. Then, major amounts of dust particles were carried by airflow into the stable regions. The remaining dust was carried to the exits of the pressure cylinders as a result of the dust backflow. As a result, areas of approximately 5 m behind of the road-headers, as well as the areas near the exits of the pressure cylinders, contained high dust concentrations. The dust concentrations near the exits of the pressure cylinders into which the dust particles had been attracted due to the strong entrainment effects, were found to increase with increasing of the ventilation velocities. However, this had only occurred when ventilation velocities had exceeded 17 m/s.

During mining operations, large amounts of coal dust escape from the heading faces. This dust presents a serious hazard to the health and safety of workers in the excavation roadways. In this study, a device was designed to capture the escaped dust in a timely way. The device was suitable for heading with forced ventilation and it could generate a fog layer with a certain thickness through the twice atomization process. The fog layer could cover the entire roadway section to filter and remove the coal dust escaping from the heading face. The performance of the proposed device was experimentally studied under different working conditions. The experimental results showed that, with the increasing of the water pressure (Pw), the particle sizes of droplets decreased while the coverage radius increased and its increasing rate gradually decelerated. Meanwhile, as the air pressure (Pa) increased, the coverage radius displayed an upward trend, and the particle sizes of the droplets decreased gradually. In this study, four different water-air pressure ranges were tested to cope with the different field conditions. Then, the proposed device and obtained test results were applied at Zhangcun Coal Mine in China. The application results indicated that the total and respirable dust suppression efficiency of the device has increased 24.8% and 43%, respectively, compared to the traditional water curtain. Also, the device was estimated to have saved approximately 25% in water consumption when compared with the water curtain method. Therefore, it is believed that the new atomization device would be ideal for replacing traditional water curtains for the suppression of hazardous dust particles in underground coal mines.

Coal gangue is a solid waste material which is generated during coal mining processes. Due to its low utilization value, it is normally discarded on gangue fields where it is stacked into very large hill formations. Spontaneous combustion is one of the major hazards which frequently occur during the long-term stacking of coal gangue. This study targeted the coal gangue stacks of the Chengzhuang Coal Mine, located in China’s Shanxi Province. The results of programmed heating tests helped determine that CO and C2H4 could be used as the index gases in the predictions of the self-heating degrees of coal gangue. Four of the typical coal gangue stacking modes which were often adopted by the Chengzhuang Mine were selected as the experimental objects of this study. The corresponding coal gangue models were piled in a field, and the self-heating degrees were measured with the passage of time. The entire experiment lasted for 60 days. The results showed that the loess isolation and loess stratified stacking methods could effectively suppress the self-heating processes. Also, the CO production and O2 consumption of the coal gangue were consequently reduced. The study also indicated that in the loess stratified stacking, the inhibitory effects on the spontaneous combustion of the coal gangue had increased with the increased thicknesses of the loess layers.

It is known that high-concentrations of dust threaten the health of road-header drivers in fully mechanized excavation faces. The regulation of the gas-solid two-phase flow in fully mechanized excavation faces is a key scientific issue for dust prevention and treatment. In this research study, a real fully mechanized excavation face was taken as the physical model. Then, a CFD-DPM method was adopted to model the gas-particle two-phase flow around a driver in a mine roadway. The results showed that there were two counter directional airflow paths on the heading face which formed three vortices, the centers of which were located in the front left, left and middle sections of the road-header, respectively, in the fully mechanized excavation face. The driver was located at the intersection of the three airflow paths. For example, the position of the driver was within the vortices from the left, front-right and rear of the road-header, respectively. The aforementioned airflows carried dust to the space around the driver through three path types including from the heading face, along the roadway floor left of the road-header, and by refluxing from the rear of the road-header. The dust concentration in front of the driver was observed to increase with a fluctuating growth trend. Also, the dust concentraion to the rear of the driver displayed stepped increases. Finally, the dust concentration which had refluxed from the rear of the driver was determined to be highest and was observed to be three times higher than the dust concentration which originated from the heading face. This study’s simulation results were verified by the results of the field measurements.

Background: Golden Syrian hamster (GSH) have many advantages as animal models in preclinical research, but their application is currently limited by the lack of standardized techniques for analyzing gene expression. Quantitative real-time polymerase chain reaction (RT-qPCR) is a sensitive method for analyzing gene expression, but its reliability depends upon the selection of stable reference (“housekeeping”) genes for proper normalization. The current study was aimed to RT-qPCR for investigated to determine the stability housekeeping gene in golden Syrian hamster.Methods: During the period of June 2019 to October 2019, the expression stability of eight commonly-used housekeeping genes (glyceraldehyde-3phosphate dehydrogenase, Gapdh; b-actin, Actb; hypoxanthine phosphoribosyl transferase 1, Hprt1; ribosomal protein L13a, Rpl13a; ribosomal protein S18, Rps18; Beta-2-microglobulin, B2m; Tubulin beta class I, Tubb; Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta, Ywhaz) were investigated in lung, liver, spleen and pancreatic tissue of golden Syrian hamsters using BestKeeper, geNorm, NormFinder software, comparative delta Ct method and RefFinder. Result: It was found that the stability of gene expression varied among tissue where in Actb was the most stably expressed housekeeping gene for lung tissue, Hprt1 for liver, Rpl13a for spleen and Tubb for pancreatic tissue. In contrast, the least stable housekeeping gene in both liver and spleen was Gapdh, Rps18 in pancreas and Ywhaz in lung tissue. These data provide a critical evaluation of housekeeping genes in GSH tissues that can be used as a guide for selection of the appropriate genes in future studies.

We embedded the genetic algorithm (GA) into the inner loop of the simulated annealing (SA) with a special designed junction. This strategy can boost the tunability of the searching process by providing two scales of regulation in seismic inversion problems. Moreover, a quantified uncertainty of the inversion result can be given when we put this strategy under Bayesian framework. Real data tests are conducted to support the theoretical calculation. Based on the conventional sparse spike inversion results, as a part of the prior information, our proposed method presents a superior quality and convincible uncertainty description.

For combined piled foundation, passive loaded piles will be subjected to horizontal force when piled foundation is loaded, and horizontal force may cause the piles horizontal displacement, instability or even failure. With inclined bedrock nearby, the mechanical behavior of passive loaded piles will be more complex. In order to study the mechanical behavior of passive loaded piles under such condition, laboratory model test was carried out, during repeatedly loading/unloading cycles. Axial force, side friction, bending moment, and lateral soil pressure were analyzed. The study is based on model test, and more related studies are needed before being applied to practical conditions. The results show as follows: Axial force distribution of the piles changes with the increase of load and becomes stable under high load. This phenomenon is related to the expansion of potential slip surface in piled foundation. The passive loaded pile that is close to load boundary has only one neutral point which is located in the lower part of the pile, and its side friction has a relatively stable direction. On the contrary, the direction of side friction of the pile that is far from load boundary changes frequently. Bending moment curves of passive loaded piles vary with the change of the distance between the piles and load boundary, and they intersect at the lower part of the pile. Bending moment is basically negative above the intersection and gradually turns into positive below it. The maximum lateral soil pressure of passive loaded pile is triple that of the adjacent soil, indicating that passive loaded pile can effectively limit the horizontal deformation of piled foundation. But when the pile is too far from load boundary, it will lose the ability to limit the horizontal deformation of piled foundation.

Terahertz high-data communication creates numerous demands for terahertz wave amplitude modulation. Here, we experimentally demonstrate a high-speed terahertz wave modulator based on 4-N,N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST)/Si hybrid structure. An externally modulated 808-nm pumping laser is utilized to generate photoexcited free carriers at the DAST medium. With the increase of illumination laser intensity, the modulation depth continues to increase in the frequency range from 0.23 to 0.35 THz. A dynamic amplitude modulation at 0.25-THz carrier wave shows that the our modulator provides a modulation speed of 1.26 MHz with a depth of up to 53% at an external pump laser irradiance of 3.5 W/cm2. Our present DAST/Si hybrid structure provides a practicable route to achieve effective signal modulation for terahertz communication system.

Neisseria gonorrhoeae is a sexually transmitted pathogen highly prevalent worldwide with an increasing trend of resistance to antimicrobial treatment. We conducted this study to trace the susceptibility of N. gonorrhoeae to penicillin (PC), spectinomycin (SPCM), ciprofloxacin (CPFX), azithromycin (AZM), cefixime (CFIX), and ceftriaxone (CTRX) in Guangxi province. In total, 303 N. gonorrhoeae isolates were obtained from patients infected with N. gonorrhoeae in 6 cities in Guangxi during 2013-2015, and the antibiotic susceptibility patterns were analyzed by an agar dilution assay. The results showed that N. gonorrhoeae was susceptible to treatment with cephalosporins, including CTRX (99.7% of isolates), CFIX (99%), SPCM (100%), and AZM (96.4%), and this is the first report of antibiotic susceptibility for AZM surveillance of N. gonorrhoeae in Guangxi. Penicillinase-producing N. gonorrhoeae (PPNG) isolates increased in prevalence from 37% in 2013 to 64% in 2015 (P = 0.068), and tetracycline-resistant N. gonorrhoeae (TRNG) prevalence increased from 23% in 2013 to 44% in 2015 (P = 0.071). High resistance of N. gonorrhoeae to PC was associated with infection in patients at ages 25 to 30 years (P ＜ 0.05), whereas PPNG positivity (P ＜ 0.01), and TRNG positivity were risk factors for CPFX resistance (P = 0.0407). Our study provides plausible evidence for therapeutic strategies and N. gonorrhoeae infection control and prevention in Guangxi, China.

Coal spontaneous combustion is a natural hazard during mining. In China, the longwall gob area is the main places that are prone to coal spontaneous combustion due to excessive residual coal in the gob and severe air leakage during underground mine ventilation. Injecting CO 2 into gob has many advantages to prevent fire disaster. However the characteristics of coal low-temperature oxidation after CO 2 injection were rarely studied. In this paper, a temperature programmed test system was adopted to simulate coal spontaneous combustion at low-temperature stage before and after CO 2 adsorption. Compositions and concentrations of gases produced by coal samples from Yiyuan mine in China at different temperatures were analyzed. It is found that with the increase of the temperature, the gas concentration of CO 2 generated from coal before CO 2 absorption, expressed the trend of exponential growth. While the CO 2 concentration after CO 2 absorption, showed the distribution of “V” type on the whole, that is, the CO 2 concentration firstly dropped to the minimum value and then rose up gradually. Before reaching to the temperature corresponding to the minimum concentration of CO 2 , the CO 2 concentration was significantly higher comparing with that before CO 2 absorption. While over that temperature, with the temperature increasing, the CO 2 concentration was obviously lower than that before CO 2 absorption. During the heating oxidation of coal, the gas concentrations of CO and C 2 H 4 showed the increasing tendency with the temperature increasing. However, the initial temperature of CO and C 2 H 4 detected firstly during the coal oxidation process after CO 2 absorption was obviously lower than that before CO 2 absorption, what's more, the concentrations of CO and C 2 H 4 were also obviously lower than that before CO 2 absorption at the same temperature, showing an obvious “hysteresis” phenomenon of inhibiting coal oxidation. The experimental results provided the basis of a method to control the spontaneous combustion of residual coal by injecting CO 2 into the gob. The field test showed that the index gas concentration of CO was reduced sharply and coal spontaneous combustion in the gob was controlled effectively.

The optimal dose of warfarin depends on polymorphisms in the VKORC1 (the vitamin K epoxide reductase complex subunit (1) and CYP2C9 (cytochrome P450 2C9) genes. To minimize the risk of adverse reactions, warfarin dosages should be adjusted according to results from rapid and simple monitoring methods. However, there are few pharmacogenetic-guided warfarin dosing algorithms that are based on large cohorts from the Chinese population, especially patients with atrial fibrillation. This study aimed to validate a pharmacogenetic-guided warfarin dosing algorithm based on results from a new rapid electrochemical detection method used in a multicenter study. Three SNPs (CYP2C9 *2, *3 and VKORC1 c.-1639G > A) were genotyped by electrochemical detection using a sandwich-type format that included a 3' short thiol capture probe and a 5' ferrocene-labeled signal probe. A total of 1285 samples from four clinical hospitals were evaluated. Concordance rates between the results from the electrochemical DNA biosensor and the sequencing test were 99.8%. The results for gene distribution showed that most Chinese patients had higher warfarin susceptibility because mutant-type and heterozygotes were present in the majority of subjects (99.4%) at locus c.-1639G > A. When the International Warfarin Pharmacogenetics Consortium algorithm was used to estimate therapeutic dosages for 362 patients with AF and the values were compared with their actual dosages, the results revealed that 56.9% were similar to actual dosages (within the 20% range). A novel electrochemical detection method of CYP2C9 *2, *3and VKORC1 c.-1639G > A alleles was evaluated. The warfarin dosing algorithm based on data gathered from a large patient cohort can facilitate the reasonable and effective use of warfarin in Chinese patients with AF.

Terahertz wave switch based on Otto coupling configuration and periodic metal V-groove structure is proposed. The reflection terahertz wave intensity from the prism-air-vanadium dioxide-metal interface is controlled by via changing external temperature. By adjusting the external temperature, the refractive index of vanadium dioxide can be changed, so that the terahertz wave reflectivity according to geometrical optics reflection is dynamically controlled. The numerical results further show that the present structure can flexibly manipulate terahertz wave transmission. The extinction ratio is about 20.18dB in our design, which has enormous potential for studying terahertz wave manipulation.