Numerical modeling of destress blasting for strata separation

Destress blasting(DB)implemented along the perimeter of safety pillars is a special application of destressing in coal longwall mining.The goal is to separate relatively more deformed mined areas from safety pillars,such as shaft pillars or cross-cut pillars,to reduce the transfer of high stresses to the protective pillar.This case study aims to numerically simulate selected destress blasts in the Czech part of the Upper Silesian Coal Basin and examine its impact on stress transfer to the safety pillar area.To separate the area between the protective pillar and the longwall(LW),two fans of five 93-mm blast holes(length of 93e100 m)were drilled from the gate roads into the overburden strata.Each set of blast holes was fired separately in two stages without time delay.The explosive charge(gelatin-type of explosive)of each stage is 3450 kg.The two DB stages were fired when the longwall face was approximately 158 m and 152 m away from the blast.A 3D mine-wide model is built and validated with in situ stress measured with hydrofracturing.Mining and destressing in three 5-m thick coal seams are simulated in the region.Numerical modeling of DB is successfully conducted using a rock fragmentation factor a of 0.05 and a stress reduction/dissipation factor β of 0.95.Buffering of transfer of additional stress from the mining area into the safety pillar is evaluated by comparison of yielding volume before and after DB.It is shown that yielding volume drops after DB by nearly 80%in the area of the destressing panel and near the safety shaft pillar.

The AGH score is a predictor of disease-free survival and targeted therapy efficacy after liver transplantation in patients with hepatocellular carcinoma

Background:Liver transplantation(LT)is the“cure”therapy for patients with hepatocellular carcinoma(HCC).However,some patients encounter HCC recurrence after LT.Unfortunately,there is no effective methods to identify the LT patients who have high risk of HCC recurrence and would benefit from adjuvant targeted therapy.The present study aimed to establish a scoring system to predict HCC recurrence of HCC patients after LT among the Chinese population,and to evaluate whether these patients are suitable for adjuvant targeted therapy.Methods:Clinical data of HCC patients who underwent LT from March 2015 to June 2019 were retrospectively collected and analyzed.Results:A total of 201 patients were included in the study.The multivariate Cox analysis suggested that preoperative alpha-fetoprotein(AFP)>200μg/L(HR=2.666,95%CI:1.515-4.690;P=0.001),glutamyl transferase(GGT)>96 U/L(HR=1.807,95%CI:1.012-3.224;P=0.045),and exceeding the Hangzhou criteria(HR=2.129,95%CI:1.158-3.914;P=0.015)were independent risk factors for poor disease-free survival(DFS)in patients with HCC who underwent LT.We established an AFP-GGT-Hangzhou(AGH)scoring system based on these factors,and divided cases into high-,moderate-,and low-risk groups.The differences in overall survival(OS)and disease-free survival(DFS)rates among the three groups were significant(P<0.05).The efficacy of the AGH scoring system to predict DFS was better than that of the Hangzhou criteria,UCSF criteria,Milan criteria,and TNM stage.Only in the high-risk group,we found that lenvatinib significantly improved prognosis compared with that of the control group(P<0.05).Conclusions:The AGH scoring system provides a convenient and effective way to predict HCC recurrence after LT in HCC patients in China.Patients with a high-risk AGH score may benefit from lenvatinib adjuvant therapy after LT.

一种通用固定式安全带悬挂装置研制

近年来,随着电网的快速发展,对变电站设备进行检修时产生的问题日益显现,在检修过程中,由于各个变电站因设计施工或设备型号等原因,变压器与线路CVT检修一直困扰着检修人员。由于基座的尺寸各有不同,传统的安全带悬挂装置并不能完全适用,以致于部分设备检修时不仅给现场作业人员带来极大的安全隐患,也降低了检修工作效率。基于上述情况,针对变压器套管与线路CVT的通用安装结构,设计了一种质量小、安装简单、造价便宜且结构牢固的通用固定式安全带悬挂装置。

Relationship between intestinal microbial dysbiosis and primary liver cancer

Background: Intestinal microbial dysbiosis is involved in liver disease pathogenesis. However, its role in primary liver cancer(PLC), particularly in hepatocarcinogenesis remains unclear. The present study aimed to study the changes in intestinal flora at various stages of PLC and clarify the relationship between intestinal microbes and PLC. Methods: Twenty-four patients with PLC(PLC group), 24 patients with liver cirrhosis(LC group), and 23 healthy control individuals(HC group) were enrolled from October 2016 to October 2017. Stool specimens of the participants were collected and the genomic DNA of fecal bacteria was isolated. High-throughput pyrosequencing of 16 S r DNA was used to identify differences in gut bacterial diversity among HC, LC, and PLC groups. We also analyzed the relationship between clinical factors and intestinal microorganisms in LC and PLC groups. Results: Diversity of Firmicutes tended to decrease from the HC to LC and PLC groups at the phylum level. Among species, Enterobacter ludwigii displayed an increasing trend in the PLC group, wherein the relative abundance of Enterobacter ludwigii in the PLC group was 100 times greater than that in the HC and LC groups. The ratio of Firmicutes/Bacteroidetes was significantly decreased with the disease progression. In addition, the linear discriminant analysis effect size method indicated that Clostridia were predominant in the gut microbiota of the HC group, whereas Enterococcaceae, Lactobacillales, Bacilli and Gammaproteobacteria may be used as diagnostic markers of PLC. Redundancy analysis showed a correlation between intestinal microbial diversity and clinical factors AST, ALT, and AFP. Veillonella showed a significant positive correlation with AFP in the PLC group, whereas Subdoligranulum showed a negative correlation with AFP. Conclusions: This study indicates that dysbiosis of the gut microbiota might be involved in PLC development and progression.

Granulocyte-macrophage colony-stimulating factor protects mice against hepatocellular carcinoma by ameliorating intestinal dysbiosis and attenuating inflammation

BACKGROUND Hepatocellular carcinoma(HCC)is the third leading cause of cancer mortality worldwide.The gut microbiota can help maintain healthy metabolism and immunity.Granulocyte-macrophage colony-stimulating factor(GM-CSF)is a critical factor in promoting health and homeostasis;it promotes intestinal immunity,stimulates bone marrow precursors to generate macrophage colonies,and enhances the antibacterial and antitumor activity of circulating monocytes.As such,GM-CSF may protect against HCC development by regulating immunity as well as intestinal microecology.AIM To investigate the impact of GM-CSF on the gut microbiome and metabolic characteristics of HCC.METHODS Thirty-six male BALB/c nude mice were divided into three groups:Control(n=10),HCC(n=13),and HCC+GM-CSF(GM-CSF overexpression,n=13).We utilized HCC cells to establish orthotopic transplantation tumor models of HCC with normal and over-expressing GM-CSF.Liver injury,immune inflammatory function and intestinal barrier function were evaluated.The fecal microbiome and metabolome were studied using 16S rRNA absolute quantification sequencing and gas chromatography-mass spectrometry.RESULTS GM-CSF overexpression significantly affected the gut microbiome of mice with HCC and resulted in a high abundance of organisms of the genera Roseburia,Blautia and Butyricimonass,along with a significant reduction in Prevotella,Parabacteroides,Anaerotruncus,Streptococcus,Clostridium,and Mucispirillum.Likewise,GM-CSF overexpression resulted in a substantial increase in fecal biotin and oleic acid levels,along with a prominent decrease in the fecal succinic acid,adenosine,fumaric acid,lipoic acid,and maleic acid levels.Correlation analysis revealed that the intestinal microbiota and fecal metabolites induced by GM-CSF were primarily involved in pathways related to reducing the inflammatory response,biotin metabolism,and intestinal barrier dysfunction.CONCLUSION GM-CSF can protect against HCC development by regulating immunity and modulating the abundance of specific intestinal microorganisms and their metabolites.This study provides new insights into the therapeutic approaches for HCC.

Analysis of permanent deformations of railway embankments under repeated vehicle loadings in permafrost regions

By large-scale dynamic tests carried out on a traditional sand-gravel embankment at the Beilu River section along the Qinghai-Tibet Railroad, we collected the acceleration waveforms close to the railway tracks when trains passed. The dynamic train loading was converted into an equivalent creep stress, using an equivalent static force method. Also, the creep equation of frozen soil was introduced according to the results of frozen soil rheological triaxial tests. A coupled creep model based on a time-hardening power function rule and the Druker-Prager yield and failure criterion was estab- lished to analyze the creep effects of a plain fill embankment under repeated train loads. The temperature field of the embankment in the permafrost area was set at the current geothermal conditions. As a result, the permanent deformation of the embankment under train loading was obtained, and the permanent deformation under the train loads to the total embankment deformation was also analyzed.

Strategic sill pillar design for reduced hanging wall overbreak in longhole mining

Steeply dipping,vein and tabular orebodies are traditionally extracted with longitudinal retreat mining methods such as Eureka and Avoca in a bottom-up sequence with delayed backfill.To increase productivity,sill pillars in the orebody are used to separate mining zones thus allowing production to take place simultaneously in two or more zones.While such mining methods are productive,they may be accompanied with high volumes of hanging wall overbreak causing significant unplanned ore dilution.In this work,it is shown through a mine design case study of a narrow vein deposit that a sill pillar could also play a significant role in limiting hanging wall overbreak.To demonstrate the role of sill pillar,a novel numerical modelling scheme is proposed to account for progressive stope wall overbreak.A numerical modelling approach of element death and rebirth is developed to allow for the detected stope overbreak to be immediately removed and replaced with backfill material before upper-level stope extraction.It is further shown that the average overbreak volume could be reduced by as much as 33%when the sill pillar is strategically placed in the lower half of a mine plan.

Dynamic behavior of the Qinghai-Tibetan railway embankment in permafrost regions under trained-induced vertical loads

The unfrozen water content and ice content of frozen soil change continuously with varying temperatures,resulting in the temperature dependence of mechanical properties of frozen soil.Thus the dynamic behavior of embankment in permafrost regions under train loading also alters with seasons.Based on a series of strong-motion tests that were carried out on the traditional embankment of Qinghai-Tibet Railway(QTR)in permafrost regions,the acceleration waveforms recorded at the embankment shoulder and slope toes were obtained.Testing results show an obvious attenuation effect on the vertical train loading from road shoulder to slope toes.Furthermore,numerical simulations of a traditional embankment under vertical train loading in different seasons were conducted,and the dynamic behavior of the embankment was described.The results show that the vibration attenuation in the cold season is greater than that in the warm season.The maximum acceleration of vibration drops to about 5%when the train vibration load is transferred through the embankment into the permafrost,and the high-frequency components are absorbed when the vibration transmits downward.Moreover,the dynamic stress under the dynamic train loading decreases exponentially with an increasing depth in different seasons.The results can be a reference for design and maintenance of embankments in permafrost regions.

Foliar carbohydrate differs between Picea crassifolia and Sabina przewalskii with the altitudinal variation of Qilian Mountains, China

Nonstructural carbohydrates （NSC） and nitrogen metabolism strongly influence growth and development in plants. The biosynthesis of cellulose and lignin （structural carbohydrates, SC） depends largely on the supply of NSC. We desire to examine which hypothesis, carbon limitation or growth limitation, best fits the alpine plant response between NSC, SC, carbon （C）, nitrogen （N） and altitude. We compared the foliar concentrations of carbohydrates, C and N between the leaves of Picea crassifolia （lower-elevation tree-line species） and Sabina przewalskii （high-elevation tree-line species） in their response to changing elevation. Our site was located in the mid-northern area of Qilian Mountains, China. We found that foliar soluble sugar （SG） concentrations were significantly higher in P. crassifolia than in S. przewalskii at the 2,700-3,400 m level. Foliar NSC levels in R crassifolia increased at the 2,700-3,100 m level, indicating that growth was limited gradually resulting in a surplus of NSC （to conform to GLH）, subsequently decreasing at the 3,100-3,400 m level, the assimilation declined leading to C deficit （to conform to CLH）. SC （SC metabolism disorders at 3,100-3,400 m）, C, N and starch were significantly lower in R crassifolia than in S. przewalskii. Conversely, foliar SG concentration shows a fall-rise trend with increasing elevation for S. przewalskii. SC concentration in S. przewalskii leaves decreased with an increase of elevation and has a significantly positive correlation to N concentration marking the assimilation of plants. Therefore, the high-elevation tree-line species （S. przewalskii） utilize or store more foliar SG leading to a decrease of SG concentration for survival and growth/regrowth in an adverse environment, higher total C, N, SC, starch contents and lower NSC level. Also, their change trends along the elevational gradient in leaves orS. przewalskii indicate better assimilation strategies for SG use under environmental stress compared to P. crassifolia. This indicates that foliar C metabolism along the elevation follows the principle of the growth-limitation hypothesis （GLH） or carbon limitation hypothesis （CLH）, which depends on the acclimation of different alpine life-forms to the environment.

High-quality draft genome sequence of Streptomyces agglomeratus 5-1-8 with strong anti-MRSA ability, isolated from the frozen soil of Tibet in China

Streptomyces agglomeratus 5-1-8 with strong anti methicillin-resistant Staphylococcus aureus(MRSA)ability,isolated from the frozen soil of Tibet in China,has a strong ability to kill the multi-drugs-resistant MRSA.To identify the second-ary metabolism ability of this strain,we describe here the phenotypic characteristics of this strain,along with its high-quality draft genome sequence,its annotation,and analysis.The 7.1M draft genome encodes 6,284 putative open reading frames(ORFs),of which 4,416 ORFs were assigned with clusters of orthologous genes(COG)categories.Also,65 t RNA genes and 24 r RNA operons were identified.The genome contains 12 gene clusters involved in antibiotics production and 1 gene cluster involved in anticancer-compounds production;4 gene clusters belong to polyketides and nonribosomal peptides,1gene cluster belong to the butyrolactone,4 gene clusters belong to the bacteriocin or lantipeptide,and 3 gene clusters belong to the others.This genome-sequence data will facilitate efforts to probe the potential of new antibiotics to kill multidrugs-resistant MRSA.

Seasonal variation of airborne fungi of the Tiantishan Grottoes andWestern Xia Museum,Wuwei,China

In this study,a systematic survey of cultural airborne fungi was carried out in the occurrence environments of wall paintings that are preserved in the Tiantishan Grottoes and the Western Xia Museum,China.A bio-aerosol sampler was used for sampling in four seasons in 2016.Culture-dependent and-independent methods were taken to acquire airborne fungal concentration and purified strains;by the extraction of genomic DNA,amplification of fungal ITS rRNA gene region,sequencing,and phylogenetic analysis,thereafter the fungal community composition and distribution characteristics of different study sites were clarified.We disclosure the main environmental factors which may be responsible for dynamic changes of airborne fungi at the sampling sites.The concentration of cultural airborne fungi was in a range from 13 to 1,576 CFU/m^(3),no significant difference between the two sites at the Tiantishan Grottoes,with obvious characteristics of seasonal variation,in winter and spring were higher than in summer and autumn.Also,there was a significant difference in fungal concentration between the inside and outside of the Western Xia Museum,the outside of the museum was far more than the inside of the museum in the four seasons,particularly in the winter.Eight fungal genera were detected,including Cladosporium,Penicillium,Alternaria,and Filobasidium as the dominant groups.The airborne fungal community structures of the Tiantishan Grottoes show a distinct characteristic of seasonal variation and spatial distribution.Relative humidity,temperature and seasonal rainfall influence airborne fungal distribution.Some of the isolated strains have the potential to cause biodeterioration of ancient wall paintings.This study provides supporting information for the pre-warning conservation of cultural relics that are preserved at local sites and inside museums.

Study of Alkali Metal Corrosion on Heating Surfaces and Bed Material Agglomerate in Biomass-fired Fluidized Bed Boiler

The bed material agglomeration and heating surface high-temperature Corrosion Problems of biomass-fired boiler in South China were studied in this work. The inner and outer surfaces of the corrosion sample were investigated by scanning electron microscope (SEM) with Bruker EDX and XRD. Results showed that the outer side of the corrosion sample was mainly composed of alkali chloride deposited ash, sulphide and a small amount of eutectoid;while the inner side of the corrosion sample was still mainly made up of the composition of SUS316, but added with alkali metal, oxygen, chlorine and sulphur elements, appearing as the corrosion products and eutectoid. It was thought that alkali chloride deposit and the reaction with pipe metal to generate low melting point eutectoid on the outer surfaces, or the corrosion reaction through the alkali metal sulphatization process was the main reasons leading to the damage of metal surface oxide film. Chlorine plays a role as haptoreaction in the corrosion process, and transports metal material as the form of chloride from the inner side to the outer side of the pipe surfaces by diffusion, accelerating the corrosion process. Meanwhile, the slag was studied by scanning electron microscope (SEM) with Bruker EDX, and the transformation process of slage was computationally analyzed by FACTSAGE. Results showed that the amount of alkali metal in the agglomerates was little, however, caused a great impact on severe agglomerates. The increase of temperature enhanced the conversion process of alkali metal to molten oxide, especially when the temperature was higher than760℃, the amount of molten product increased sharply. Thus, the temperature control of fluidized bed plays an important role in solving the problem of alkali metal agglomerates;it also reliefs the volatile of alkali metal into gas phase, benefiting the control of heating surface corrosion.

Seasonal variation of foliar δ^(13)C values and its indictor significance in Sabina przewalskii and Sabina chinensis

Seasonal variation of foliar δ13C values as well as proline, silicon, MDA and relative water content in Sabina przewalskii Kom. and S. chinensis （Lin.） Ant. were measured. The results show that foliar δ13C values were significantly different at different seasons： lower in winter but higher in summer. δ13C values were positively correlated with air temperature and soil temperature. This demonstrates that foliar δ13C of Sabina is a successful empirical indictor of temperature. Furthermore, foliar δ13C values were positively related to proline and silicon content, and negatively related to relative water content and MDA content. Compared with S. chinensis, S. przewalskii has higher δ13C values, proline and silicon content as well as lower MDA and relative water content. All these results provided strong evidence that it is feasible for δ13C to be regarded as another index to evaluate freezing tolerance of Sabina.

Methods for extraction of microorganism DNA from glacier surface snow

In order to thoroughly investigate the diversity of glacier microorganisms, four DNA extraction methods with differem lysis pat- terns were tested and two screened methods （the Bosshard-Bano method and the Zhou method） were optimized for the most ef- fective form of the filter membrane （cut vs. uncut）, the DNA extraction method, and the precipitation method. The two optimized methods were then compared with the commercial Mo-Bio DNA extraction kit, and the results showed that the kit was generally suitable for extraction of microorganism DNA fi＇om glacier surface snow. Procedurally, it was found that a modified Boss- hard-Bano method （i.e., cutting the filter membrane into pieces, using a specific lysis pattern [lysozyme （5 mg/mL）-protease K （ 1 mg/mL）-CTAB （ 1%）-SDS （ 1%）], performing the extraction only once by chloroform-isoamyl alcohol （24： 1）, and conducting DNA precipitation by pure ethanol） was also an effective and less expensive method for extraction of microorganism DNA from glacier surface snow.

Database Development Based on MFC Application in Management of Curriculum Information

There are hundreds of records in the curriculum of our Language Learning Lab every semester and every record has several important properties. It takes too much time to manage the information in the traditional way and it always makes mistakes. Managing the information with database technology, designing program to access the database with Visual c tool, setting a combobox in the application UI and inquiring curriculum information by selecting the room name in the combobox. It is easy to operate the program for the staff members. The result is accurate, this way promotes the efficiency of managing information.

Effect of inhibiting P38MAPK on inflammatory factors and cell apoptosis during flap ischemia-reperfusion injury

Objective:To study the effect of inhibiting P38 mitogen activated protein kinase (P38MAPK) on inflammatory factors and cell apoptosis during flap ischemia-reperfusion injury. Methods:Wistar rats were selected as experimental animals and randomly divided into control group, model group and intervention group (n=12), control group were made into routine abdominal superficial arteriovenous flap models, model group were made into ischemia-reperfusion flap models and intervention group were made into ischemia-reperfusion flap models and then received SB202190 intervention. 8 d after flap making, tissue was collected to detect the expression of inflammatory factors and apoptosis molecules as well as the levels of oxidative stress indicators.Results:NF-κB, IL-6, TNF-α, Bax and Caspase-3 mRNA expression and protein expression in flap tissue of model group were significantly higher than those of control group (P<0.05), ROS, MDA, AOPP and 8-OHdG levels were significantly higher than those of control group, and Bcl-2 mRNA expression and protein expression were significantly lower than those of control group (P<0.05);NF-κB, IL-6, TNF-α, Bax and Caspase-3 mRNA expression and protein expression in flap tissue of intervention group were significantly lower than those of model group (P<0.05), ROS, MDA, AOPP and 8-OHdG levels were significantly lower than those of model group (P<0.05), and Bcl-2 mRNA expression and protein expression were significantly higher than those of model group (P<0.05).Conclusions:Inhibiting P38MAPK can reduce the transplanted flap ischemia-reperfusion injury caused by inflammation, oxidative stress and cell apoptosis.

丰水地区混凝土检查井底板渗漏非开挖修复施工方法

检查井是市政管道工程的重要组成部分。检查井渗漏会造成土壤污染、水环境污染、水土流失,严重时会导致地面掏空坍塌,引发安全事故,因此采取有效的方法对检查井渗漏进行修复至关重要。近年来,在老旧排水管网系统改造中,非开挖修复方法越来越被广泛采用。文章基于新都区毗河流域水环境综合整治PPP项目-清流镇雨污水管网改造工程实践,对丰水地区混凝土检查井底板渗漏非开挖修复的施工工艺流程和施工方法进行了分析、总结,供类似工程参考借鉴。

Correlations Between Foliar Stable Carbon Isotope Composition and Environmental Factors in Desert Plant Reaumuria soongorica （Pall.） Maxim.

Leaves of 407 individuals of Reaumuria soongorica （Pall.） Maxim. collected from the major distribution areas were measured to investigate the distribution characteristics of the stable carbon isotope in this desert plant, as well as correlations between δ^13C values and environmental factors. Results showed that δ^13C values in R. soongorica ranged from -22.77‰ to -29.85‰ and that the mean δ^13C value （-26.52‰） was higher than a previously reported δ^13C value for a different desert ecosystem. This indicates that R. soongorica belongs to the C3 photosynthetic pathway and has higher water use efficiency than other species. The correlations between δ^13C values and environmental factors demonstrated that the foliar δ^13C values in R. soongorica increased significantly with decreasing mean annual precipitation and mean relative humidity, and decreased with decreasing duration of sunshine and evaporation. The spatial distribution trend of δ^13C values in R. soongorica was not obvious and there was no significant correlation between the δ^13C values and mean annual temperature. We conclude that different distribution trends in δ^13C values for R. soongorica were likely caused by stomatal limitation rather than by nutrient-related changes in photosynthetic efficiency and that precipitation played an important role in the wide distribution range of R. soongorica. This pattern of δ^13C values for R. soongorica reinforced that it is a super-xerophil in terms of its adaptive strategies to a desert environment.

Relative humidity reconstruction for northwestern China's Altay Mountains using tree-ring δ^(18)O

Relative humidity is an important factor in water and water vapor feedback cycles.In this study,we established a 222-year annual tree-ring δ^(18)O chronology for Siberian larch(Larix sibirica Ldb.)from the Altay Mountains in northwestern China.Climate response analyses revealed that the relative humidity was the primary factor limiting tree-ring δ^(18)O fractionation.Based on our analysis,tree-ring δ^(18)O can be used to reconstruct the July–August relative humidity based on both a reasonable mechanism of tree-ring δ^(18)O fractionation and a statistically significant regression model.We used this model to reconstruct variations in the July–August relative humidity,and the model explained 47.4% of the total variation in the measured relative humidity data from 1961 to 2011.The relative humidity in the study area increased from 1900 to the 1990s and decreased thereafter.Two regime-shift dry periods were detected during the study period(one from 1817 to 1830 and the other from 2004 to 2011).

Physiological Responses of Limonium aureum Seeds to Ultra-drying

The seeds of Limonium aureum （L.） Hill. were dried from 8.92% to 2.88% moisture content in a desiccating container with silica gel. After ultra-drying the seeds were accelerated aged （50 ℃, 1 month）, and some physiological indices, including the electrical conductivity, dehydrogenase activity, superoxide dismutase （SOD）, peroxidase （POD）, glutathione reductase （GR）, ascorbate peroxidase （APX）, catalase （CAT）, volatile aldehydes and malondialdehyde （MDA） were tested. The results indicated that dehydrogenase, POD, SOD, GR, APX and CAT activities of the ultra-dry seeds were higher than the control seeds, while volatile aldehydes and malondialdehyde were lower than the control group. The results suggest that ultra-drying is beneficial for maintaining the vigor of L. aureum seeds at a high level. Thus, L. aureum seeds could be stored under ultra-dry conditions.