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Objective The Ordos block, with typical boundary zone activity, is located in the center of mainland China. Influenced by the remote action of the Tibetan Plateau in the southwest and the Pacific Plate in the east, each boundary zone of the Ordos Block exhibits distinct tectonic activity and deformation characteristics. This study aims to provide insights into the characteristics of strong earthquake generation and the future seismic risk along the boundaries of the Ordos active block. Methods This study systematically summarizes research achievements made in the study of active faults and the seismogenic mechanism of strong earthquakes around the Ordos Block over the past few decades, providing a systematic overview of the characteristics of fault activity and seismic generation mechanisms along the block' s periphery. Conslusion The differences in fault activity in each boundary zone determined the differences in the earthquake-breeding strong tectonic environments. In the southern section of the western boundary, the faults are mainly characterized by strike-slip, reverse strike-slip, and thrust owing to the influence of the northward compression and expansion of the Qinghai-Tibet Plateau, resulting in complex structural deformation styles within the boundary zone. In the northern section of the western boundary, the latest expansion boundary of the Qinghai-Tibet Plateau is characterized by dextral movement along the Sanguankou-Niushoushan fault. The Yinchuan Basin in the northern section of the western boundary zone is a typical fault basin with basin-controlling faults exhibiting dextral strike-slip characteristics, and earthquakes are primarily of the standard strike-slip type. The Hetao Basin on the northern boundary is controlled by normal faults on its northern side, with historical and ancient earthquakes concentrated on the northern boundary faults. The Weihe Basin on the southern boundary exhibits relatively complex structural features, comprising two sets of normal faults. Historical major earthquakes mostly occur at the southern edge of the basin, with moderate seismic activity in the central-northern part of the basin. The Shanxi Graben system on the eastern boundary comprises multiple rift-type basins. Historical major earthquakes exhibit a pattern of stronger activity in the south and weaker activity in the north. The northern basins are influenced by the Zhang-Bo tectonic belt, resulting in significant changes in basin trend and fault movement characteristics, often possessing the structural conditions necessary for earthquakes of around M 7.0. Overall, in the typical fault activity zones surrounding the Ordos active block, future strong earthquakes are more likely to occur in seismic gaps or transition zones of fault systems, where significant time has passed since the occurrence of major earthquakes or at the intersections of tectonic zones.

Objective.To evaluate the application value of the fluorescence PCR probe melting curve (MeltPro) technique in the detection of isoniazid drug- resistance of Mycobacterium tuberculosis (MTB) in sputum samples. Methods.In this study, we collected sputum samples of PTB that were identified as MTB by GeneXpert MTB/RIF method(MTB positive) from 2021 to 2022. These sputum samples were detected including smear, Myco- bacterium culture, GenoType MTBDRplus,and isoniazid drug-resistance test by MeltPro technique. We did the proportional drug sensitivity test (DST) of isoniazid for culturing positive strains, analyzed the influence of the amount of bacteria in sputum samples on the results of MeltPro technique, compared the difference in the detection rate of isoniazid resistance by proportional DST, GenoType MTBDRplus, and MeltPro technique, The proportional DST results of isoniazid were used as a standard to evaluate the isoniazid drug-resistance detection efficiency of MeltPro technique and GenoType MTBDRplus. Results.157 qualified MTB positive sputum samples were collected, after Mycobacterium culture, we got 130 strains. The rate of success for isoniazid in sputum samples detected by MeltPro technique was84.1%(132/157). Among different grades of sputum smear results, there is a difference in the successful rate of MeltPro technique (H = 24.169,P = 0.000), increased with the grade of sputum smear results, the successful rate was increased from64.8% (32/54,the negative sputum)to 100.0%(17/176/6,the positive sputum grade 3+4+), the successful rate also increased with the increase of MTB grade detected by GeneXpert MTB/RIF, from54.8%(17/31,the very low sputum) to 96.4%(27/28,the high sputum)and the difference between each grade was statistically significant (H = 27.763,P = 0.000). The detection rate of isoniazid resistance using MeltPro technique, GenoType MTBDRplus and proportional DST were 22.0%(29/132),15.3%(19/124),14.6%(19/130), respectively. There was no statistically significant difference between the three methods (χ2 = 2.997,P = 0.223). Based on the results of proportional DST, the sensitivity, specificity, positive predictive value and negative predic- tive value of MeltPro technique in the detection of isoniazid were 84.6%(11/13)91.2%(93/102)55%(11/20) 97.9%(93/95), respectively, Kappa is 0.614. The sensitivity, specificity, positive predictive value and negative predictive value of GenoType MTBDRplus in the detection of isoniazid were 55.6%(10/18)92.3%(84/91), 58.8% (10/17), 91.3%(84/92),respectively, Kappa is 0.490. Conclusion.The MeltPro technique has high sensitivity and specificity in detecting MTB isoniazid resistance in sputum samples of pulmonary tuberculosis patients, and can quickly and accurately screen for isoniazid resistance in patients, To improve the success rate of testing, it is necessary to pay attention to the selection of sputum samples when promoting the application in grassroots laboratories. [ABSTRACT FROM AUTHOR]

Methane production from lignocellulosic feedstock through high solid anaerobic digestion is a huge potential technology. However, the shortage of an efficient reactor has become a major bottleneck in developing the technology. The continuous feeding and discharge of lignocellulosic feedstock with high solids is difficult to complete. Methane production from the feedstock is low in practice. Thus, it is important to develop a new reactor with efficient feeding and discharge feedstock equipments and improve methane production by an optimized operation process. Based on synthesizing the merits of a number of techniques home and abroad, a novel anaerobic reactor was designed in this study. The reactor had two spiral equipments to implement continuous feeding and discharge feedstock with high solid content and had a high bearing capability of organic loading rate (OLR) to improve methane production. In order to provide a technology and some reliable operating parameters to efficiently produce methane from lignocellulosic feedstock, the continuous anaerobic co-digestion tests were conducted at three total solid contents of 10%, 15% and 20% using corn stalk and dairy manure as feedstock. An integrated two-phase division digestion system was constructed by controlling stirring intensity (h/d) and feeding intensity (d). The methane volumetric production rate (MVPR) of different OLRs was compared. Effects of the total solid (TS) of feedstock, stirring, feeding intensity on height, pH of function divisions, and MVPR were discussed in detail. The results showed that function divisions, including the acidification division of upside and methanogenic division of underpart in the vertical reactor, were obviously formed when TS were 10% and 15%, MVPR gradually increased, and methane content stabilized around 52% with OLR increasing. The highest MVPR reached 1.62 and 1.66 m3/(m3·d) respectively when OLR was 13.44 kg/(m3·d) at 10% TS and 20.17 kg/(m3·d) at 15% TS. MVPR significantly decreased when OLR was 20.17 kg/(m3·d) and 30.0 kg/(m3·d), respectively, which might be caused by the accumulation of volatile fatty acids. MVPR stabilized around 0.98 m3/(m3·d) with OLR increasing, then it dramatically decreased and anaerobic digestion failed when OLR reached 30.0 kg/(m3·d) at 20% TS. The results of two factors interacting declared the highest MVPR at 1.63-1.69 m3/(m3·d) The efficient acidification division and methanogenic division were formed, and the height ratio of both was 1.1-1.6:1 when stirring intensity, feeding intensity, and TS were 6-12 h/d, 6.5-10 d, and 10%-15%, respectively. In summary, the process of continuous feeding and discharge at 10%-20% TS of lignocellulosic feedstock was feasible in the anaerobic digestion reactor. The reactor was more efficient and stable to produce methane at 10% and 15% TS compared to 20% TS, and MVPR could be improved by adjusting stirring intensity and feeding intensity. Therefore, this technology has a promising prospect for industrial scale application. [ABSTRACT FROM AUTHOR]