Assessment of CH_(4) flux and its influencing drivers in the rice-wheat agroecosystem of the Huai River Basin,China

To understand the CH_(4) flux variations and their climatic drivers in the rice-wheat agroecosystem in the Huai River Basin of China,the CH_(4) flux was observed by using open-path eddy covariance at a typical rice-wheat rotation system in Anhui Province,China from November 2019 to October 2021.The variations and their drivers were then analyzed with the Akaike information criterion method.CH_(4) flux showed distinct diurnal variations with single peaks during 9:00-13:00 local time.The highest peak was 2.15μg m^(-2)s^(-1)which occurred at 11:00 in the vegetative growth stage in the rice growing season(RGS).CH_(4) flux also showed significant seasonal variations.The average CH_(4)flux in the vegetative growth stage in the RGS(193.8±74.2 mg m^(-2)d^(-1))was the highest among all growth stages.The annual total CH_(4) flux in the non-rice growing season(3.2 g m^(-2))was relatively small compared to that in the RGS(23.9 g m^(-2)).CH_(4) flux increased significantly with increase in air temperature,soil temperature,and soil water content in both the RGS and the non-RGS,while it decreased significantly with increase in vapor pressure deficit in the RGS.This study provided a comprehensive understanding of the CH_(4) flux and its drivers in the rice-wheat rotation agroecosystem in the Huai River Basin of China.In addition,our findings will be helpful for the validation and adjustment of the CH_(4) models in this region.

高分子包膜缓控释肥养分释放机制及模型研究现状

新型缓控释肥料作为研究热点已有大量成果,但针对缓控释肥料的养分释放机制及养分释放影响因素的研究还相对较少。文中从高分子膜材料出发,分析各类高分子材料的特点,总结出现有高分子材料包膜缓释肥的养分释放机制主要为扩散机制和破裂机制。由于膜材料种类繁多且养分释放过程的复杂性,现有养分释放机制无法准确地评价高分子包膜缓释肥性能,需要通过建立缓释模型的方式来描述高分子包膜缓释肥养分释放情况,文中综述了现有新型缓控释肥料的养分释放模型,并且提出将肥料缓释模型与植物生长养分需求相结合,可进一步提高缓控释肥料的养分利用率。

营养免疫炎性指标预测免疫联合放化疗二线治疗食管鳞癌患者预后的价值

目的:评估营养免疫炎性指标用于预测接受camrelizumab联合放(化)疗二线治疗复发和(或)转移转移食管鳞癌(relapsed or metastatic esophageal squamous cell carcinoma,R/M ESCC)患者预后的价值。方法:从2018年1月至2021年3月,从河北医科大学第四医院筛选出48例符合入组标准的R/M ESCC患者进行回顾性分析,根据受试者工作特征曲线(receiver operating characteristic curve,ROC)确定预后营养指数(prognostic nutritional index,PNI)、中性粒细胞淋巴细胞比(neutrophilic-tolymphocyte ratio,NLR)、血小板与淋巴细胞比(platelet-to-lymphocyte ratio,PLR)和全身免疫-炎症指数(systemic immune-inflammation index,SII)这4项指标预测患者预后的最佳临界值。应用SPSS 25.0版本软件进行单因素和多因素统计学分析。结果:全组患者二线免疫治疗后的1、2年生存(overall survival,OS)率和无进展生存(progression-free survival,PFS)率分别为42.9%、22.5%和29.0%、5.8%;中位OS和PFS分别为9.0个月(95%CI:6.4~11.7)和8.5个月(95%CI:1.5~5.6)。多因素分析结果显示免疫联合方式、近期疗效、PNI、NLR、PLR和SII为患者OS的独立影响因素(P=0.044、0.030、<0.001、0.040、0.044、0.036);免疫联合方式、使用免疫周期数、近期疗效、PNI、NLR、PLR和SII为患者PFS的独立影响因素(P=0.049、0.024、0.003、0.017、0.008、<0.001、0.009)。结论:低PNL,高NLR、PLR和SII值为接受camrelizumab联合放(化)疗二线治疗R/M ESCC预后较差的独立性预测指标。

Orthodontic simulation system with force feedback for training complete bracket placement procedures

Background A virtual system that simulates the complete process of orthodontic bracket placement can be used for pre-clinical skill training to help students gain confidence by performing the required tasks on a virtual patient.Methods The hardware for the virtual simulation system is built using two force feedback devices to support bi-manual force feedback operation.A 3D mouse is used to adjust the position of the virtual patient.A multi-threaded computational methodology is adopted to satisfy the requirements of the frame rate.The computation threads mainly consist of the haptic thread running at a frequency of>1000Hz and the graphic thread at>30Hz.The graphic thread allows the graphics engine to effectively display the visual effects of biofilm removal and acid erosion through texture mapping.Using the haptic thread,the physics engine adopts the hierarchy octree collision-detection algorithm to simulate the multi-point and multi-region interaction between the tools and the virtual environment.Its high efficiency guarantees that the time cost can be controlled within 1 ms.The physics engine also performs collision detection between the tools and particles,making it possible to simulate paint and removal of colloids.The surface-contact constraints are defined in the system;this ensures that the bracket will not divorce from or embed into the tooth during the adjustment of the bracket.Therefore,the simulated adjustment is more realistic and natural.Results A virtual system to simulate the complete process of orthodontic bracket bonding was developed.In addition to bracket bonding and adjustment,the system simulates the necessary auxiliary steps such as smearing,acid etching,and washing.Furthermore,the system supports personalized case training.Conclusions The system provides a new method for students to practice orthodontic skills.

Spatial Agglomeration and Diffusion of Population Based on a Regional Density Function Approach:A Case Study of Shandong Province in China

Population density functions have long been used to describe the spatial structure of regional population distributions.Several studies have been conducted to examine the population distribution in Shandong Province,China,but few have applied regional density functions to the analysis.Therefore,based on the 2000,2010,and 2020 population censuses,this study used monocentric and polycentric regional density functions to study the characteristics of population agglomeration and diffusion in Shandong.This is followed by an in-depth discussion based on population growth rate data and hot-and cold-spot analyses.The results showed that the Shandong Province population was spatially unevenly distributed.Population growth rates were higher in urban centers and counties,with more significant changes in population size in the eastern coastal areas than in the inland areas.As verified in this study,the logarithmic form of the single-center regional density function R2 was greater than 0.8,which was in line with the population spatial structure of Shandong Province.During the study period,the estimated population density of the regional center and the absolute value of the regional population density gradient both increased,indicating a clear and increasing trend of centripetal agglomeration of regional centers over the study period.Overall,the R2 value of the multicenter region density function was higher than that of the single-center region density function.The polycentric regional density function showed that the population density gradient of some centers had a downward trend,which reflected the spatial development trend of outward diffusion in these centers.Meanwhile,the variation in the estimated population density and the population density gradient exhibited differences in the central population distribution patterns at different levels.

Photocatalytic water splitting of ternary graphene-like photocatalyst for the photocatalytic hydrogen production

In recent times,there has been an increasing demand for energy which has resulted in an increased consumption of fossil fuels thereby posing a number of challenges to the environment.In the course finding possible solutions to this environmental canker,solar photocatalytic water splitting to produce hydrogen gas has been identified as one of the most promising methods for generating renewable energy.To retard the recombination of photogenerated carriers and improve the efficiency of photocatalysis,the present paper reports a facile method called the hydrothermal method,which wa s used to prepare ternary graphene-like photocatalyst.A“Design Expert”was used to investigate the influence of the loading weight of Mo and GO as well as the temperature of hydrothermal reaction and their interactions on the evolution of hydrogen(H 2)in 4 h.The experimental results showed that the ternary graphene-like photocatalyst has a strong photocatalytic hydrogen production activity compared to that of pure SiC.In particular,the catalyst added 2.5 wt%of GO weight yielded the highest quantum of 21.69%at 400-700 nm of wavelength.The optimal evolution H2 in 4 h conditions was obtained as follows:The loading weight of Mo was 8.19 wt%,the loading weight of GO was 2.02 wt%,the temperature of the hydrothermal reaction was 200.93℃.Under the optimum conditions,the evolution of H2 in 4h could reach 4.2030 mL.