Transport of Heavy Metals between Soil and Rice in the Jiulong River River Basin

Diet is one of the main pathways for heavy metals to enter the human body,so studying the content of heavy metals in agricultural products and evaluating them is of great significance.When farmland soil is contaminated with heavy metals,the heavy metals accumulated in the soil will be absorbed by the roots of rice plants growing on it,and will migrate and transform between different tissues and organs of rice plants.There is a significant correlation between heavy metal pollution in soil and the content of heavy metals in rice.The migration and enrichment of heavy metals in the agricultural soil rice system is a complex process that is influenced by many factors,such as the physical and chemical properties of the soil,the content and occurrence forms of heavy metals in the soil,and the physiological characteristics of rice plants.In actual field environments,these influencing factors have significant spatial differences and are relatively complex.Therefore,it is necessary to conduct practical analysis of the various influencing factors in actual field environments.Based on actual data analysis,studying the heavy metal content in rice and the characteristics of heavy metal accumulation and migration in rice plants is of great significance for improving the food safety of rice.

纳米纤维素在功能纳米材料中的应用进展

纳米纤维素分为纤维素纳米纤维(CNF)、纤维素纳米晶体(CNC)、细菌纳米纤维素(BNC)。CNF主要由机械法和2,2,6,6-四甲基哌啶-1-氧基(TEMPO)介导氧化法制备,呈微纤丝状。CNC主要由酸水解法制备,呈棒状或针状颗粒。BNC由细菌合成,呈纳米纤维网络状。文中综述了纳米纤维素在凝胶、仿生复合材料、导电材料、电极材料、导热材料、电磁屏蔽材料、压电材料及传感器材料领域的应用现状,并对其功能纳米材料未来发展的方向进行了展望。

Mechanism underlying the protective effect of Kaixin Jieyu Fang on vascular depression following cerebral white matter damage

The Chinese compound Kaixin fieyu Fang can be used to treat vascular depression; however, the underlying mechanism remains unclear. This study established a rat model of chronic cerebral ischemia-caused white matter damage by ligation of the bilateral common carotid arteries. Rats received daily intragastric administration of a suspension of Kaixin ]ieyu Fang powder. After 3, 7 and 21 days of treatment, the degree of white matter damage in the cerebral ischemia rat model was alleviated, Bcl-2 protein and mRNA expression in brain tissue increased, and Bax protein and mRNA expression decreased. These results indicate that Kaixin Jieyu Fang can alleviate cere- bral white matter damage, and the underlying mechanism is associated with regulation of Bcl-2/ Bax protein and mRNA expression, which is one of possible mechanism behind the protective effect of Kaixin Jieyu Fang against vascular depression.

纳米材料介导的磁技术在外科疾病诊疗中的应用前景

外科技术的发展使得手术禁区逐渐减少,以往不能解决的许多病症采用新技术即可得到有效治疗.飞速发展的纳米材料和技术为外科的发展提供给了新的工具和方法.根据医学临床应用的需要,材料科学家们已经设计和开发出各种具有特殊功能和结构的纳米材料,实现传统材料难以达到的性能.其中,磁性纳米材料具有独特的磁学特性以及远程非接触式磁场可控的能力,在生物医学领域展现了巨大的应用潜力,是外科应用的一个不可或缺的重要发展方向.本文将聚焦于基于纳米材料的磁技术在外科疾病诊疗中的应用前景,主要从以下几个方面进行论述:医用磁性纳米材料的概述;纳米材料介导的磁技术在外科疾病诊断中的研究进展;纳米材料介导的磁技术在外科疾病治疗中的研究进展.

Magnetoresponsive nanozyme:magnetic stimulation on the nanozyme activity of iron oxide nanoparticles

The iron oxide nanoparticles(IONPs)that combine the nanozyme activity and magnetothermal properties have attracted significant interest for various biomedical applications.However,the effect of magnetic stimulation in fine-tuning the nanozyme activities remains unclear.Here,we have constructed a series of IONPs with different magneto-thermal conversion abilities,and systematically study the effect of magnetic field stimulation on the peroxidase(POD)activity of IONPs.The results show that POD activity is effectively amplified via an in situ alternating magnetic field(AMF)stimulation with no solution temperature rise,and the degree of activity enhancement is closely related to the magnetic heating ability of the IONPs,confirming the origin of activity enhancement arises from the local magnetothermal effect.As the first report to prove magnetothermal regulation on nanozyme activity and to shed lights on the underlying correlation between activity enhancement and the intrinsic specific absorption rate(SAR),this work is expected to provide important support for future design of new magnetoresponsive nanozymes in various practical applications.

Stability of selenium and its speciation analysis in water using automatic system separation and HR-ICP-MS measurement

A simple and convenient method has been developed for the pre-concentration and separation of inorganic selenium species from environmental water samples using anion exchange chromatographic column combined with high resolution inductively coupled plasma mass spectrometry(HR-ICP-MS)measurement.^(75)Se(Ⅳ) and ^(75)Se(Ⅵ)were prepared and used as tracers during the experiments.The volatility of selenium during solution evaporation was investigated to establish a reliable water samples pretreatment procedure.The parameters which affect the uptake of Se(Ⅳ)and Se(Ⅵ)on Dowex1×8 resin was optimized and the procedure for Se(Ⅳ)and Se(Ⅵ)separation was proposed.Both Se(Ⅳ)and Se(Ⅵ)are retained on the column in natural or alkaline solution with high distribution coefficient.The successive gradient elution of pre-concentrated species of selenium with HNO_(3)solution allows to differentiate between them.Se(Ⅳ)and Se(Ⅵ)finally were eluted with 0.05 mol/L HNO_(3) and 5.0 mol/L HNO_(3),respectively.The proposed method has been successfully verified using the certified reference materials(CRMs)of real water samples,and spiked recoveries for real samples were 98%-104%with 5%relative standard deviations(RSDs).The developed procedure is proved to be reliable and can be used for the rapid determination of selenium species in environmental water samples.

Spatiotemporal changes and influencing factors of the intensity of agricultural water footprint in Xinjiang, China

Xinjiang Uygur Autonomous Region,the largest agricultural high-efficiency water-saving arid area in China,was adopted to explore the coupling relationship between agricultural water consumption and economic benefits,which is of great significance to guiding the efficient utilization and sustainable development of agricultural water resources.This study utilizes an indicator,termed the Agricultural Water Footprint Intensity(short as AWFI,which means the amount of water resource consumed per unit of agricultural GDP),to study the economic benefits of agricultural water in Xinjiang from 1991-2018.In addition,the Theil index,a measure of the imbalance between individuals or regions,was used to study the evolution in the spatial differences in water efficiency,and the Logarithmic Mean Divisia Index(LMDI)method was applied to quantify the factors driving the AWFI.The results showed that AWFI in Xinjiang has experienced three stages:obvious decline,stable and slow decline,which decreased from 16114 m^(3)/10^(4) CNY to 2100 m^(3)/10^(4) CNY,decreasing by 86.97%.The Theil index indicated that the spatial evolution of 14 prefectures(cities)resembled an inverted N-shaped Kuznets curve over time.Among the influencing factors,the contributions of water-saving technology and planting structure to the change in the AWFI in Xinjiang,China from 1991 to 2018 were 154.03%and−37.98%,respectively.The total contribution to AWFI of the total population,urbanization rate,and production scale was−16.06%.This study concluded that further improvements in the economic benefits of agricultural water consumption can be obtained by continuing to promote more efficient or“water-conservation”irrigation technologies(engineering aspects),adjusting the planting structure(policy guidance aspects),and intensive management of cultivated land(management aspects).