Stability mechanism and control of the pumpable supports in longwall recovery room

The load-bearing performance(LBP)of pumpable supports(PPS)is crucial for the stability of longwall pre-driven recovery room(PRR)surrounding rock.However,the unbalanced bearing coefficient(UBC)of the PPS(undertaking unequal load along the mining direction)has not been investigated.A mechanical model of the PRR was established,considering the main roof cantilever beam structure,to derive an assessment formula for the load,the failure criteria,and the UBC of the PPS.Subsequently,the generation mechanisms,and influencing factors of the UBC were revealed.Global sensitivity analysis shows that the main roof hanging length(l_(2))and the spacing between the PPS(r)significantly impact the UBC.A novel design of the PPS and the coupling control technology were proposed and applied to reduce the UBC of the PPS in the adjacent longwall PRR.Monitor results showed no failure of the PPS at the test site,with the UBC(ζ)reduced to 1.1 consistent with the design value(1.15)basically,fully utilizing the collaborative LBP of the PPS.Finally,the maximum roof-to-floor convergence of the PRR was 234 mm,effectively controlling the stability of the surrounding rock of the PRR and ensuring the mining equipment recovery.

A combined computational/experimental study of anode-concerned voltage drop in aqueous primary Mg-air batteries

The voltage drop appearing at Mg anode-electrolyte interface is a critical issue for the battery power and energy density of aqueous primary Mg-air batteries.The respective voltage loss is typically assigned to the deposits layer forming on the anode surface during discharge.In this work,we experimentally and computationally investigate the critical factors affecting the voltage drop at Mg anode towards a deeper understanding of the contribution of deposit and its growth.A two-dimensional(2D)mathematical model is proposed to compute the voltage drop of Mg-0.15Ca wt.%alloy(Mg-0.15Ca)by means of a semi-empirical formulas and experiments-based modification model,considering the effect of discharge current density,the negative difference effect(NDE)and surface deposits layer itself.This model is utilized to simulate the discharge potential of the anode at predefined experimental current densities.The computed voltage drop(half-cell voltage)is in good agreement with the experimental value.The applicability of the mathematical model is successfully validated on the second material(namely high-purity Mg).

Effect of probiotic treatment on cirrhotic patients with minimal hepatic encephalopathy: A meta-analysis

Background: Minimal hepatic encephalopathy(MHE) is an early and reversible form of hepatic encephalopathy. The documentations on the treatment with probiotics are inconsistent. The present meta-analysis was to verify the role of probiotics in the treatment of cirrhotic patients with MHE.Data sources: Seven electronic databases were searched for relevant randomized controlled trials(RCTs)published until July 2015. The effects of probiotics on serum ammonia, endotoxin, and MHE were evaluated.Results: A total of 14 RCTs(combined n = 1132) were included in the meta-analysis. When probiotics were compared to placebo or no treatment, probiotics were more likely to reduce values in the number connection test(NCT; week 4: MD =-30.25, 95% CI:-49.85 to-10.66), improve MHE(week 4: OR = 0.18,95% CI: 0.07 to 0.47; week 12: OR = 0.15, 95% CI: 0.07 to 0.32), and prevent overt HE progression(week4: OR = 0.22, 95% CI: 0.07 to 0.67) in patients with liver cirrhosis. When probiotics was compared to lactulose, probiotics tended to reduce serum ammonia levels(week 4: MD =-0.33 μmol/L, 95% CI:-5.39 to 4.74; week 8: MD = 6.22 μmol/L, 95% CI:-24.04 to 36.48), decrease NCT(week 8: MD = 3.93, 95% CI:-0.72 to 8.58), improve MHE(week 4: OR = 0.93, 95% CI: 0.45 to 1.91; week 12: OR = 0.73, 95% CI: 0.35 to 1.51) and prevent the development of overt HE(week 4: OR = 0.96, 95% CI: 0.17 to 5.44; week 12:OR = 2.7, 95% CI: 0.50 to 14.64) in patients with liver cirrhosis. However, lactulose appears to be more effective in reducing NCT values as compared to probiotics(week 4: MD = 6.7, 95% CI: 0.58 to 12.82).Conclusion: Probiotics can decrease serum ammonia and endotoxin levels, improve MHE, and prevent overt HE development in patients with liver cirrhosis.

Inhibition of Differentiation by Transforming Growth Factor β1 in Rhabdomyosarcoma Cells

OBJECTIVE To study the effect of transforming growth factor β1 （TGF-β1） on differentiation of rhabdomyosarcoma （RMS） cells METHODS RD （human embryonal RMS cell line） cells, cultured in differentiation medium containing 9-cis retinoic acid （9CRA）, were treated with TGF-β1. Proliferation of the cells was examined by the MTT assay. The differentiation specific proteins （sarcomeric actin and MyHC） and myogenic transcription factors （MyoD1 and myogenin） in the RD cells were assessed by immunofluorescence staining. RESULTS Compared to control cells, treatment with lower concentrations of TGF-β1 （0.1 and 0.2 ng/ml） induced an increase in OD values after 4 d （P〈0.01）, whereas higher concentrations of TGF-β1 （2 and 5 ng/ml） led to a reduction of cell viability （P〈0.01）. After exposure to 9CRA, the viability of the cells decreased significantly （P〈0.01）, while sarcomeric actin, MyHC and myogenin were induced. These changes were antagonized by TGF-β1 （0.1 ng/ml）. No changes were observed in expression of MyoD1. CONCLUSION The RMS cells, derived from myogenic progenitors are committed to a myogenic fate, but are arrested in the differentiation course by the addition of TGF-β1 which represses some of the myogenic transcription factors.

Micro-alloyed Mg-Ca:Corrosion susceptibility to heating history and a plain problem-solving approach

The exceptionally low corrosion rate(∼0.1 mm y^(–1)in concentrated NaCl solution for 7 days)enables lean Mg-Ca alloys great potential for diverse applications,particularly if relevant properties(e.g.mechanical strength,electrochemical performance,etc.)can be enhanced by thermomechanical processing.However,herein it is demonstrated that the corrosion performance of lean Mg-Ca is susceptible to the heating process.The corrosion rate of Mg-0.15 wt%Ca alloy is remarkably accelerated after annealing even for a short time(4 h at 400℃)because Fe precipitation readily takes place.Fortunately,it is found that micro-alloying with dedicated additional elements is able to solve this problem.Nevertheless,the problem-solving capability is dependent on the element category,particularly the ability of the alloying element to constrain the Fe precipitation.Among the three studied elements(i.e.Sn,Ge and In),only In shows good competence of restricting the formation of Fe-containing precipitates,thereby contributing to retention of the superior corrosion resistance after annealing even at a rigorous condition(24 h at 450℃).The finding creates good foundation for follow-up work of developing lean Mg-Ca-based alloys combining high corrosion resistance,superior electrochemical performance with excellent mechanical properties for applications as biodegradable implants and anode materials for aqueous batteries.

The light and hypoxia induced gene ZmPORB1 determines tocopherol content in the maize kernel

Tocopherol is an important lipid-soluble antioxidant beneficial for both human health and plant growth. Here, we fine mapped a major QTLqVE1 affecting γ-tocopherol content in maize kernel, positionally cloned and confirmed the underlying gene ZmPORB1(por1), as a protochlorophyllide oxidoreductase. A 13.7 kb insertion reduced the tocopherol and chlorophyll content, and the photosynthetic activity by repressing ZmPORB1 expression in embryos of NIL-K22, but did not affect the levels of the tocopherol precursors HGA(homogentisic acid)and PMP(phytyl monophosphate). Furthermore, ZmPORB1 is inducible by low oxygen and light, thereby involved in the hypoxia response in developing embryos. Concurrent with natural hypoxia in embryos, the redox state has been changed with NO increasing and H_(2)O_(2) decreasing, which lowered γ-tocopherol content via scavenging reactive nitrogen species. In conclusion, we proposed that the lower lightharvesting chlorophyll content weakened embryo photosynthesis, leading to fewer oxygen supplies and consequently diverse hypoxic responses including an elevated γ-tocopherol consumption. Our findings shed light on the mechanism for fine-tuning endogenous oxygen concentration in the maize embryo through a novel feedback pathway involving the light and low oxygen regulation of ZmPORB1 expression and chlorophyll content.

Climate change impacts the distribution of Quercus section Cyclobalanopsis(Fagaceae),a keystone lineage in East Asian evergreen broadleaved forests

East Asian evergreen broadleaved forests(EBFLs) harbor high species richness,but these ecosystems are severely impacted by global climate change and deforestation.Conserving and managing EBLFs requires understanding dominant tree distribution dynamics.In this study,we used 29 species in Quercus section Cyclobalanopsis-a keystone lineage in East Asian EBLFs-as proxies to predict EBLF distribution dynamics using species distribution models(SDMs).We examined climatic niche overlap,similarity,and equivalency among seven biogeographical regions’ species using’ecospat’.We also estimated the effectiveness of protected areas in the predicted range to elucidate priority conservation regions.Our results showed that the climatic niches of most geographical groups differ.The western species under the Indian summer monsoon regime were mainly impacted by temperature factors,whereas precipitation impacted the eastern species under the East Asian summer monsoon regime.Our simulation predicted a northward range expansion of section Cyclobalanopsis between 2081 and 2100,except for the ranges of the three Himalayan species analyzed,which might shrink significantly.The greatest shift of highly suitable areas was predicted for the species in the South Pacific,with a centroid shift of over 300 km.Remarkably,only 7.56% of suitable habitat is currently inside protected areas,and the percentage is predicted to continue declining in the future.To better conserve Asian EBLFs,establishing nature reserves in their northern distribution ranges,and transplanting the populations with predicted decreasing numbers and degraded habitats to their future highly suitable areas,should be high-priority objectives.

Two new species of Polyalthiopsis(Annonaceae) based on morphological characters and phylogenetic evidence,with a supplementary description of P.chinensis from China

Two new species of Polyalthiopsis(Annonaceae),P.nigra Y.H.Tan & Bin Yang from Guangxi and Yunnan Provinces and P.xui Y.H.Tan & Bin Yang from Yunnan Province,are described and illustrated.P.nigra is morphologically similar to P.chinensis in having narrowly elliptic-oblong,lemon to yellowish green petals,but differs by having obovoid monocarps,a higher number of leaf secondary veins,leaf blades usually widest above the middle,and a lower ratio of leaf blade length to width.P.xui is morphologically similar to P.floribunda in having axillary inflorescences,1-3(-4) flowers,elliptic leaves,and ellipticovate petals,but differs in the numbers of carpels per flower and ovules per carpel.The molecular phylogenetic analysis using five plastid markers confirm that the two new species belong to the genus Polyalthiopsis and show clear interspecific divergences between P.nigra and P.xui and between them and other species in the genus.Detailed descriptions,colored photographs,and habitat and distribution data for the two new species are provided.In addition,the fruit morphology of P.chinensis is described for the first time,based on living collections.Geographical distributions and a diagnostic key for all Polyalthiopsis species are also presented.

Engineered exosomes-based theranostic strategy for tumor metastasis and recurrence

Metastasis-associated processes are the predominant instigator of fatalities linked to cancer,wherein the pivotal role of circulating tumor cells lies in the resurgence of malignant growth.In recent epochs,exosomes,constituents of the extracellular vesicle cohort,have garnered attention within the field of tumor theranostics owing to their inherent attributes encompassing biocompatibility,modifiability,payload capacity,stability,and therapeutic suitability.Nonetheless,the rudimentary functionalities and limited efficacy of unmodified exosomes curtail their prospective utility.In an effort to surmount these shortcomings,intricate methodologies amalgamating nanotechnology with genetic manipulation,chemotherapy,immunotherapy,and optical intervention present themselves as enhanced avenues to surveil and intercede in tumor metastasis and relapse.This review delves into the manifold techniques currently employed to engineer exosomes,with a specific focus on elucidating the interplay between exosomes and the metastatic cascade,alongside the implementation of tailored exosomes in abating tumor metastasis and recurrence.This review not only advances comprehension of the evolving landscape within this domain but also steers the trajectory of forthcoming investigations.

Chrysophanol inhibits the progression of gastric cancer by activating nod-like receptor protein-3

Aim:Gastric cancer(GC)is one of the most common malignant tumors.Chrysophanol has been reported to possess antitumor effects on a variety of cancers;however,its role in GC remains unclear.This study aimed to investigate the effects of chrysophanol on the proliferation,pyroptosis,migration,and invasion of GC cells.Methods:Human GC cell lines MKN 28 and AGS cells were treated with different concentrations of chrysophanol,then cell proliferation,migration,invasion and pyroptosis were determined by CCK-8,colony-forming assay,wound healing assay,Transwell assay,and flow cytometry.Cell migration and invasion were reassessed in these transfected cells following the transfection of nod-like receptor protein-3(NLRP3)siRNA in MKN 28 and AGS cells.To examine the downstream signaling pathway of the NLRP3 signaling pathway,NLRP3,caspase-1,gasdermin-D,interleukin(IL)-1β,and IL-18 were detected by quantitative real-time-polymerase chain reaction or western blotting.Results:Chrysophanol inhibited the proliferation of GC cells,caused pyroptosis,inhibited cell migration and invasion,and increased the expression of NLRP3 inflammasomes in GC cells.Knockdown of NLRP3 inhibited the effects of chrysophanol on proliferation,pyroptosis,migration,and invasion of GC cells.Chrysophanol plays an anticancer role by enhancing NLRP3.Conclusions:Chrysophanol exerts anti-neoplastic effects in vitro in GC cells by modulating NLRP3,thus highlighting its therapeutic potential in GC.

儿童盲和低视力的病因与屈光状态及远用助视器康复研究

目的:分析儿童盲和低视力的病因、屈光状态、屈光矫正和配用光学远用助视器矫正后的视力情况。方法:选取2015-12/2018-04我科门诊接诊及盲校筛查的6～16岁低视力儿童和盲童212例422眼,通过相关检查明确病因和屈光状态,对部分患儿进行屈光矫正和光学远用助视器验配矫正,分析矫正后视力情况。结果:儿童盲和低视力病因以先天性和遗传性眼病为主,本组病例中先天性白内障是首位原因(19.3%),低视力屈光不正以轻中度远视和近视多见(65.3%),屈光矫正后脱盲率(26.4%)和脱残率(14.6%)均低于联合远用助视器验配矫正后的脱盲率(58.3%)和脱残率(91.1%),差异均有统计学意义(P<0.01)。结论:儿童盲和低视力病因复杂,应加强预防和筛查工作,低视力儿童应常规进行屈光矫正并配合使用远用助视器矫正,以利获得满意的康复效果。

气相氟化合成氢氟烯烃催化剂的研究进展

氢氟烯烃(HFOs)是重要的精细化工中间体,气相氟化合成HFOs具有可连续生产、避免对反应釜的严重腐蚀等优点,简化生产工艺已成为国内外生产氟化工产物的重要方法.本文简要介绍了合成HFOs的常见催化反应类型以及反应机制,并按照主催化剂成分分类概述气相氟化合成所用的催化剂,介绍了各类催化剂的传统制备方法(如沉淀法等)和新的制备方法(如自组装法、溶液燃烧合成法、硬模板法、静电纺丝法等),以及催化性能,提出了该催化剂的未来发展方向.

Stability control of gob-side entry retained under the gob with close distance coal seams

In multi-seam mining,the interlayer rock strata between the upper coal seam(UCS)and the lower coal seam(LCS)appear damage and strength weakening after mining the UCS.Ground stability control of the gob-side entry retaining(GER)under the gob with close distance coal seams(CDCS)is faced with difficulties due to little attention to GER under this condition.This paper focuses on surrounding rock stability control and technical parameters design for GER under the gob with CDCS.The floor rock strata damage characteristics after mining the UCS is first evaluated and the damage factor of the interlayer rock strata below the UCS is also determined.Then,a structural mechanics model of GER surrounding rock is set up to obtain the main design parameters of the side-roadway backfill body(SBB)including the maximum and minimum SBB width calculation formula.The optimal SBB width and the water-to-cement ratio of high water quick-setting material(HWQM)to construct the SBB are determined as 1.2 m and 1.5:1.0,respectively.Finally,engineering trial tests of GER are successfully carried out at#5210 track transportation roadway of Xingwu Colliery.Research results can guide GER design under similar mining and geological conditions.

Small ubiquitin-related modifier paralogs are indispensable but functionally redundant during early development of zebrafish

The Small ubiquitin-related modifier （SUMO） conjugation to a variety of proteins regulates diverse cellular processes, including transcription, cell cycle regulation and maintenance of genome integrity. To investigate in vivo biological function of SUMO paralogs, we inactivated them in the early development of zebrafish. While zebrafish embryos deficient for all three SUMO paralogs, as Ubc9-deficient ones, displayed severe defects, loss of individual SUMO paralog was compatible with a normal development. SUMO-deficient embryos can be rescued by a single human or zebrafish SUMO. While key structural basic lysine residues and N-terminal unstructured stretch of SUMO are critical for in vivo rescue, the consensus Kll sumoylation site of SUMO2 is dispensable, implying that chain formation on this potential site is unessential for normal development. Inactivation of all three SUMOs triggered p53- dependent apoptosis and further inactivation of p53 restored normal zebrafish development. Interestingly, we also demonstrate that the dominant negative truncated form of p53, Δ113p53, significantly blunts SUMO depletion-induced p53 activity in vivo. Taken together, our results suggest that SUMO paralogs are indispensable, but redundant, in the early development of zebrafish.

Contributions to the flora of Myanmar from 2000 to 2019

Myanmar is botanically rich and floristically diverse:one of the world's biodiversity hotspots.However,Myanmar is still very unevenly explored,and until a plant checklist was published in 2003,relatively little work was done on its flora.This checklist included 11,800 species of spermatophytes in 273 families.Since this checklist was published,the botanical exploration of Myanmar has accelerated and there have been many additional publications.We therefore surveyed the literature of taxonomic contributions to Myanmar’s vascular flora over the last 20 years(2000e2019)and compiled a list of new and newly described taxa.Our list includes 13 genera,193 species,7 subspecies,19 varieties,and 2 forms new to science;and 3 families,34 genera,347 species,4 subspecies,7 varieties,and 1 form newly recorded in Myanmar.Altogether,they represent 91 families and 320 genera.Most of the new discoveries belong to 15 families,with more than 25%(146 taxa)belonging to Orchidaceae.These new discoveries are unevenly distributed in the country,with about 41%of the newly discovered species described from Kachin State in northeast Myanmar.This reflects the incompleteness of our current knowledge of the flora of Myanmar and the urgent need for a greatly expanded effort.The completion of the flora of Myanmar requires more fieldwork from north to south,taxonomic studies on new and existing collections,and some mechanism that both coordinates the efforts of various international institutions and initiatives and encourages continued international cooperation.In addition,producing modern taxonomic treatments of the flora of Myanmar requires the participation of experts on all vascular plant families and genera.There is also an urgent need to attract young scientists to plant taxonomy,to work on inventories,identification,nomenclature,herbarium work,and comparative studies.

Corrosion and discharge performance of Mg-9%Al-2.5%Pb alloy as anode for seawater activated battery

To obtain a new kind of Mg?Al?Pb alloy anode material with low content of Pb, the corrosion and discharge behavior of Mg?9%Al?2.5%Pb (hereafter in mass fraction) alloy were investigated by immersion tests and electrochemical techniques, and compared with those of Mg?6%Al?5%Pb alloy. The results indicate that Mg?9%Al?2.5%Pb alloy exhibits a lower self-corrosion rate and higher utilization efficiency in contrast with Mg?6%Al?5%Pb alloy because of the higher content of Al. As the result of the decrease of Pb content, the discharge activity of Mg?9%Al?2.5%Pb alloy is relatively weaker but still meets the requirement of anode. These results reveal that Mg?9%Al?2.5%Pb alloy with a low content of Pb can serve as a good candidate for the anode material used in seawater activated battery.

Kalman Filter Estimation of Lithium Battery SOC Based on Model Capacity Updating

High-precision estimation of lithium battery SOC can effectively optimize vehicle energy management,improve lithium battery safety protection,extend lithium battery cycle life,and reduce new energy vehicle costs.Based on the forgetting factor recursive least square method(FFRLS),Thevenin equivalent circuit model and Singular Value Decomposition-Unscented Kalman Filter(SVD-UKF),the SVD-UKF combined lithium battery SOC estimation algorithm with model capacity update is proposed,aiming at further improving the SOC estimation accuracy of lithium battery.The parameter identification of Thevenin model is studied by using the forgetting factor recursive least square method.To overcoming the shortcomings of Kalman filter linearization error and non-positive definite covariance matrix,the singular value decomposition unscented Kalman filter algorithm is proposed.It is worth mentioning that in order to consider the impact of battery available capacity attenuation on the estimation of lithium battery SOC,the model capacity update algorithm is used to optimize the model parameters and state joint estimation algorithm based on FFRLS&SVD-UKF.Verified by simulation and lithium battery test,the results show that the SVD-UKF algorithm based on model capacity update can accurately estimate the SOC of lithium battery in real time with the available capacity of lithium battery continuous attenuation.The purpose of improving the accuracy of SOC estimation of lithium batteries is achieved.

Soil heavy metal pollution from Pb/Zn smelting regions in China and the remediation potential of biomineralization

Smelting activities pose serious environmental problems due to the local and regional heavy metal pollution in soils they cause. It is therefore important to understand the pollution situation and its source in the contaminated soils. In this paper, data on heavy metal pollution in soils resulting from Pb/Zn smelting(published in the last 10 years) in China was summarized. The heavy metal pollution was analyzed from a macroscopic point of view. The results indicated that Pb, Zn, As and Cd were common contaminants that were present in soils with extremely high concentrations. Because of the extreme carcinogenicity, genotoxicity and neurotoxicity that heavy metals pose, remediation of the soils contaminated by smelting is urgently required. The primary anthropogenic activities contributing to soil pollution in smelting areas and the progressive development of accurate source identification were performed. Due to the advantages of biominerals, the potential of biomineralization for heavy metal contaminated soils was introduced. Furthermore, the prospects of geochemical fraction analysis, combined source identification methods as well as several optimization methods for biomineralization are presented, to provide a reference for pollution investigation and remediation in smelting contaminated soils in the future.

Research on Direct Yaw Moment Control Strategy of Distributed-Drive Electric Vehicle Based on Joint Observer

Combined with the characteristics of the distributed-drive electric vehicle and direct yaw moment control,a double-layer structure direct yaw moment controller is designed.The upper additional yaw moment controller is constructed based on model predictive control.Aiming at minimizing the utilization rate of tire adhesion and constrained by the working characteristics of motor system and brake system,a quadratic programming active set was designed to optimize the distribution of additional yaw moments.The road surface adhesion coefficient has a great impact on the reliability of direct yaw moment control,for which joint observer of vehicle state parameters and road surface parameters is designed by using unscented Kalman filter algorithm,which correlates vehicle state observer and road surface parameter observer to form closed-loop feedback correction.The results show that compared to the“feedforward+feedback”control,the vehicle’s error of yaw rate and sideslip angle by the model predictive control is smaller,which can improve the vehicle stability effectively.In addition,according to the results of the docking road simulation test,the joint observer of vehicle state and road surface parameters can improve the adaptability of the vehicle stability controller to the road conditions with variable adhesion coefficients.

Numerical tests of theoretical models describing ionization of H(1s) atom by linearly polarized flat pulse of laser radiation

We derive the well-known Coulomb correction factor for the Gordon-Volkov wave function describing an outgoing electron in the process of ionization in an intense laser field. Although rigorous treatment would limit its use only to laser fields much lower than the so-called barrier-suppression field, it appears that in practice the correction factor may be used also close to and even above this critical value of the laser field. We compare predictions of several analytical expressions describing ionization rate of the hydrogen atom in its ground state in the strong linearly polarized laser field. We also compare ionization probabilities obtained by integrating these ionization rates over a temporal envelope of the laser pulse with predictions based on the exact numerical solution to the time-dependent Schr ¨odinger equation.