Mechanical properties of foamed polyurethane solidified ballasted track

Foamed Polyurethane Solidified Ballasted Track(FPSBT),an innovative railway track,is formed by solidifying ballast bed with foamed polyurethane.Compared with the traditional Discrete Ballasted Track(DBT),FPSBT does not require regular maintenance such as tamping and cleaning.However,limited studies exist on the mechanical properties of FPSBT.In this study,Laboratory experiments are conducted on polyurethane samples to investigate the effects of polyurethane density on the mechanical properties of FPSBT.Furthermore,the performance of DBT and FPSBT with different polyurethane densities are compared,and the recommended polyurethane density is obtained.FPSBT exhibited negligible accumulation of deformation under cyclic loads,indicating excellent performance of FPSBT owing to the anti-deformation properties of polyurethane.Further,a track load vehicle test is conducted.FPSBT exhibited better load-transmitting ability than DBT.Finally,the construction and application of FPSBT in China are introduced.This study is expected to contribute to realizing a more extensive application of FPSBT.

FaSnRK1a mediates salicylic acid pathways to enhance strawberry resistance to Botrytis cinerea

Strawberry is a major fruit crop worldwide because its nutritional and health benefits to human health,but its productivity is limited by Botrytis cinerea.Sucrose nonfermentation 1-related protein kinase 1(SnRK1)has a defense function against pathogens,but the function of SnRK1 in the defense response to B.cinerea in plants is still unclear.In this study,FaSnRK1a-OE and RNAi fruits were constructed and then inoculated with B.cinerea.The result reveals a positive role of Fa SnRK1a in the regulation of resistance to gray mold.FaSnRK1a affects SA content by regulating FaPAL1 and FaPAL2 expressions.The genes related to the SA signaling pathway(FaTGA1 and FaTGA2.1)were significantly increased/decreased in FaSnRK1a-OE or FaSnRK1a-RNAi fruit,respectively.FaSnRK1a interacted with the FaWRKY33.2 protein and negatively regulated FaWRKY33.2 expression,and FaWRKY33.2 acts as a repressor of disease resistance to B.cinerea.Finally,FaSnRK1a regulates the expression of six PR genes and the activities of antioxidant enzymes to boost defense response after B.cinerea inoculation.Our findings showed that FaSnRK1a increases the resistance of strawberry fruit to B.cinerea via SA signaling pathway and interaction with the FaWRKY33.2 transcription factor.

Analysis of a Rare Heavy Rain Weather Process in Autumn in Ulanqab City

Based on the conventional observation data and NCEP/NCAR reanalysis data,the circulation situation,influencing systems and causes of the heavy rain during September 20-21,2010 in Ulanqab City were analyzed from the evolution process of weather circulation situation and the changes of various physical quantity fields.The results show that there was an obvious frontal zone between 45-52°N,which brought strong cold air.The transport of warm and humid air outside the subtropical high and typhoon was the main water vapor source of the strong precipitation,and the southwest jet at 700 hPa transported abundant water vapor.There was a broad inverted trough to the south of 45°N,with a central value of 1000.0 hPa.Ulanqab City was on the top of the inverted trough,stable and less moved,which was conducive to the occurrence of systematic heavy precipitation.The rainstorm was a strong precipitation process caused by the intersection of cold air brought by the southward movement of the upper frontal zone and warm and humid air outside the subtropical high.After the precipitation,the invasion of strong cold air brought frost and cold wave weather to Ulanqab City.

A Study on the expression of erbB4/HER4 in non-small cell lung cancer

Objective: To test the expression of HER4 in non-small cell lung cancer (NSCLC) and elucidate the relationship between its over-expression and the clinical pathology of NSCLC. Methods: 70 cases of paraffin-embedded tissues from informative NSCLC were tested for the expression of HER4 by means of immunohistochemical assay. Results: HER4 were overexpressed in NSCLC in 91.4%. The overexpression of HER4 correlated only with the lymph node metastasis, TNM staging and survival after operation. Conclusion: ErbB4 is one of the genes to regulate the growth of NSCLC in advanced stages and artificial interference of the overexpression of HER4 in NSCLC might be a good way for the treatment of NSCLC in advanced stages.

Defects in photoreduction reactions:Fundamentals,classification,and catalytic energy conversion

Powered by optical energy,photocatalytic reduction for fuel production promises to be an ideal long-term solution to a number of key energy challenges.Photocatalysts with enhanced light absorption,fast electron/hole separation rates,and exposed activity sites are essential to improve photocatalytic efficiency.Semiconductors are constrained by their own intrinsic properties and have limited performance in photocatalysis,but defect engineering provides an opportunity to modulate the physical and chemical properties of semiconductors.Defect engineering has been shown to be effective in regulating electron distribution and accelerating photocatalytic kinetics during photocatalysis.This review introduces the definition and categorization of defects,then explains the main effects of defect engineering on photoabsorption,carrier separation/migration,and surface reduction reactions.We then review the milestones in the design of defect-engineered photocatalysts for key chemical reactions,including hydrogen evolution,CO_(2)reduction,and N_(2)reduction,and tabulate their respective effects on catalytic performance.Finally,we provide insights and perspectives on the challenges and potential of defect engineering for photoreduction reactions.

Towards understandings of serine/arginine-rich splicing factors

Serine/arginine-rich splicing factors(SRSFs)refer to twelve RNA-binding proteins which regulate splice site recognition and spliceosome assembly during precursor messenger RNA splicing.SRSFs also participate in other RNA metabolic events,such as transcription,translation and nonsensemediated decay,during their shuttling between nucleus and cytoplasm,making them indispensable for genome diversity and cellular activity.Of note,aberrant SRSF expression and/or mutations elicit fallacies in gene splicing,leading to the generation of pathogenic gene and protein isoforms,which highlights the therapeutic potential of targeting SRSF to treat diseases.In this review,we updated current understanding of SRSF structures and functions in RNA metabolism.Next,we analyzed SRSF-induced aberrant gene expression and their pathogenic outcomes in cancers and non-tumor diseases.The development of some well-characterized SRSF inhibitors was discussed in detail.We hope this review will contribute to future studies of SRSF functions and drug development targeting SRSFs.

冷激条件下预形成副溶血性弧菌生物被膜的发展变化

【目的】生物被膜可附着在食品或医药生物材料表面引起持续性的感染,而现今极少有关于温度变化对预形成生物被膜影响的研究。本文分析了冷激条件下副溶血性弧菌预形成生物被膜的发展变化。【方法】以改进的结晶紫染色法检测生物被膜总量,以改进的超声法和Lowry法量化胞外多糖和蛋白质,以RNA试剂盒提取并纯化生物被膜形成的相关基因。同时,激光共聚焦扫描显微镜直观显示了冷激条件下预形成生物被膜形态结构的变化,并深入分析了生物被膜结构的变化,以及生物被膜结构参数和基因转录的相关性。【结果】在冷激条件下,副溶血性弧菌生物被膜总量增加,同时,副溶血性弧菌预形成的生物被膜胞外多聚物的主要成分胞外多糖和蛋白质也逐渐增加,被膜形成相关鞭毛基因和毒力基因的转录活跃。生物被膜的平均厚度(MT)、平均扩散距离(ADD)、孔隙率(P)、生物被膜粗糙度(BR)和均匀性(H)在冷激过程中也发生了变化,同时这些参数之间存在显著相关性(P<0.01),而生物被膜结构参数与生物被膜相关基因转录的相关性较弱(P<0.05)。【结论】因此,4°C和10°C冷激不能完全抑制副溶血性弧菌预形成生物被膜的生长,风险评估人员在制定控制食源性感染风险的战略时应考虑到这一因素。

Evaluation of the Biodiversity Conservation Function in Liaohe Delta Wetland,Northeastern China

The scientific evaluation of the wetland biodiversity conservation function is the basis of balanced wetland protection and development. Our research sought to provide references for the protection of wetland ecological environments as well as the related planning and management policies. The study established a fitting model for evaluating the biodiversity conservation function in the Liaohe Delta, northeastern China. The new model, the Wetland Biodiversity Conservation Indicator(WBCI), was with four input factors, including the vegetation coverage(VC), habitat suitability index(HI), land use and land cover(LULC) index(LI), and threat factor index(TI) of the LULC type. The values assigned to HI and TI were based on Integrated Valuation of Ecosystem Services and Tradeoffs(In VEST)habitat quality models. The weights of all the factors in WBCI were valued with the Principal Component Analysis(PCA). We evaluated the wetland biodiversity conservation function of Panjin, Liaohe Delta, China, by using the WBCI model based on Gaofen-1(GF-1) satellite data in 2018, and the result was verified with In VEST and other models. It showed that the output map was similar to that of In VEST, with the higher-quality habitat including the wetland, tidal flat, water body, and forest, as well as the lower-quality land use types including the paddy field, crop field, construction land, and land used by traffic. The wetland biodiversity conservation function was better in areas less affected by human disturbance, with very abundant species and good-quality habitat. It was poor in areas impacted by more frequent human activities such as the land cultivation, housing, and traffic, which led to the landscape fragmentation. The WBCI model provided a more accurate reflection of the bird distribution than the In VEST model. The WBCI model was able to reflect the difference in quality of each habitat grade, in contrast to the net primary productivity(NPP) method and species distribution models(SDMs). The new model was, therefore, simpler and suitable in reflecting the quality of wetland biodiversity function in the Liaohe Delta.

Dynamic Response of Phragmites australis and Suaeda salsa to Climate Change in the Liaohe Delta Wetland

Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are therefore of great importance. We used medium-and high-resolution satellite data, meteorological station data, and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta Wetland from 1998 to 2017, as well as their growth response to the climate change. The results showed that during 1998–2017, the areas of both P. australis and S. salsa wetlands alternated through periods of decreasing,increasing, and then decreasing trends. The annual change in the area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index(NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged, and decreased accounted for 81.8%, 12.3%, and 5.9%, respectively, of the total area;evaporation and wind speed were the main meteorological factors affecting the NDVI;and contribution rates of the climate change and human activities to the NDVI were 73.2% and 26.8%, respectively. The area with vegetation cover being mainly S.salsa that was improved, unchanged, and decreased accounted for 63.3%, 18.3%, and 18.4%, respectively, of the total area;and no meteorological factors significantly affected the NDVI of S. salsa in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover.The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity.

Quantifying the interannual litterfall variations in China’s forest ecosystems

Aims Litterfall is a key parameter in forest biogeochemical cycle and fire risk prediction.However,considerable uncertainty remains regarding the litterfall variations with forest ages.Quantifying the interannual variation of forest litterfall is crucial for reducing uncertainties in large-scale litterfall prediction.Methods Based on the available dataset(N=318)with continuous multi-year(≥2 years)measurements of litterfall in Chinese planted and secondary forests,coefficient of variation(CV),variation percent(V_(P)),and the ratio of next-year litterfall to current-year litterfall were used as the indexes to quantify the interannual variability in litterfall.Important Findings The interannual variations of litterfall showed a declining trend with increasing age from 1 to 90 years.The litterfall variations were the largest in 1-10 years(mean CV=23.51%and mean V_(P)=−28.59%to 20.89%),which were mainly from tree growth(mean ratio of next-year to current-year=1.20).In 11-40 years,the interannual variations of litterfall gradually decreased but still varied widely,mean CV was~18%and mean V_(P) ranged from−17.69%to 21.19%.In 41-90 years,the interannual variations minimized to 8.98%in mean CV and~8%in mean V_(P).As a result,forest litterfall remained relatively low and constant when stand age was larger than 40 years.This result was different from the previous assumptions that forest litterfall reached relatively stable when stand age was larger than 30,20 or even 15 years.Our findings can improve the knowledge about forest litter ecology and provide the groundwork for carbon budget and biogeochemical cycle models at a large scale.

Interleukin-12 supports in vitro self-renewal of long-term hematopoietic stem cells

Hematopoietic stem cells(HSCs)self-renew or differentiate through division.Cytokines are essential for inducing HSC division,but the optimal cytokine combination to control self-renewal of HSC in vitro remains unclear.In this study,we compared the effects of interleukin-12(IL-12)and thrombopoietin(TPO)in combination with stem cell factor(SCF)on in vitro self-renewal of HSCs.Single-cell assays were used to overcome the heterogeneity issue of HSCs,and serum-free conditions were newly established to permit reproduction of data.In single-cell cultures,CD150^(+)CD48^(-)CD41^(-)CD34^(-)c-Kit^(+)Sca-1^(+)lineage^(-)SCs divided significantly more slowly in the presence of SCF+IL-12 compared with cells in the presence of SCF+TPO.Serial transplantation of cells from bulk and clonal cultures revealed that TPO was more effective than IL-12 at supporting in vitro self-renewal of short-term(<6 months)HSCs,resulting in a monophasic reconstitution wave formation,whereas IL-12 was more effective than TPO at supporting the in vitro selfrenewal of long-term(>6 months)HSCs,resulting in a biphasic reconstitution wave formation.The control of division rate in HSCs appeared to be crucial for preventing the loss of self-renewal potential from their in vitro culture.