Promising outcomes 5 weeks after a surgical cervical shunting procedure to unclog cerebral lymphatic systems in a patient with Alzheimer’s disease

Recently,the glymphatic system has been recognised as an important‘waste solutes transport channel’within the brain.1 Studies have shown that blockage of the glymphatic system leads to increased beta-amyloid deposits,accelerating the onset and progression of Alzheimer’s disease(AD).12 Given that cervical lymph nodes receive cerebrospinal fluid from the brain’s glymphatic system,34 we speculated that decompression of the lymphatic trunk and cervical lymphatic-venous anastomosis(LVA)could facilitate the flow of cerebrospinal fluid in the cranial glymphatic system,potentially accelerating the clearance of harmful beta-amyloid and tau proteins.We collaborated with surgeons who specialise in LVA supermicrosurgery for maxillofacial tumours and lymphoedema to develop a procedure to relieve the blockage of the glymphatic system.This surgery employs supermicrosurgery techniques to create LVA connecting the bilateral cervical,deep lymphatic vessels to the veins,resulting in lymphatic trunk decompression,which allows the lymph fluid in the high-pressure lymphatic vessels to flow into the low-pressure venous system.The goal of the minimally invasive surgery is to enhance the removal of proteins,such as beta-amyloid and tau,from the brain’s lymphatic systems to the maxillofacial lymphatic vessels,unclogging protein blockages within the brain.This extracranial procedure is safer than intracranial approaches.

Dissolved metal ion removal by online hollow fiber ultrafiltration for enhanced size characterization of metal-containing nanoparticles with single-particle ICP-MS

Single particle-inductively coupled plasma mass spectrometry (SP-ICP-MS) is a powerful tool for size-characterization of metal-containing nanoparticles (MCNs) at environmentally relevant concentrations,however,coexisting dissolved metal ions greatly interfere with the accuracy of particle size analysis.The purpose of this study is to develop an online technique that couples hollow fiber ultrafiltration (HFUF) with SP-ICP-MS to improve the accuracy and size detection limit of MCNs by removing metal ions from suspensions of MCNs.Through systematic optimization of conditions including the type and concentration of surfactant and complexing agent,carrier pH,and ion cleaning time,HFUF completely removes metal ions but retains the MCNs in suspension.The optimal conditions include using a mixture of 0.05 vol.%FL-70 and 0.5 mmol/L Na2S2O_(3)(pH=8.0) as the carrier and 4 min as the ion cleaning time.At these conditions,HFUF-SP-ICP-MS accurately determines the sizes of MCNs,and the results agree with the size distribution determined by transmission electron microscopy,even when metal ions also are present in the sample.In addition,reducing the ionic background through HFUF also lowers the particle size detection limit with SP-ICP-MS (e.g.,from 28.3 to 14.2 nm for gold nanoparticles).This size-based ion-removal principle provided by HFUF is suitable for both cations (e.g.,Ag+) and anions (e.g.,AuCl_(4)^(-)) and thus has good versatility compared to ion exchange purification and promising prospects for the removal of salts and macromolecules before single particle analysis.

国家自然科学基金环境化学发展规划概况

环境化学是研究化学物质在环境介质中存在、特性、行为、效应及其污染控制原理和方法的科学,是化学科学的重要分支和环境科学的核心学科.近年来,国内环境化学面向学科前沿和国家重大需求,坚持问题导向,突出前瞻、创新、交叉、应用,在污染防控、生态建设和人民健康等方面均取得了长足进步.为了顺应我国生态文明建设对环境化学提出的新需求,使环境化学科学研究更加对接"四个面向",切实解决我国目前所面临的环境污染问题,本文简要介绍了国家自然科学基金委员会化学科学部环境化学学科发展规划与学科布局,供相关人员参考.

大气中活性气态汞的分析方法和赋存转化

活性气态汞(Reactive gaseous mercury, RGM),在大气环境中通常被认为是气态的氧化汞,主导大气汞沉降过程,对汞的全球循环至关重要。本文详细介绍了RGM的多种采样和分析方法,讨论并比较了当前技术的优势和局限性;对RGM在大气中的生成、赋存、清除等环境过程以及相关的机制进行了梳理,并探究各过程在大气汞循环过程中的贡献。针对当前RGM分析的难点(如赋存浓度低、采集困难)与关键科学问题(如赋存形态与转化),需着力发展实际环境中RGM采集和形态分析的可行方法,进而深入探究其环境行为。大气中RGM的分析方法和环境行为研究是极具挑战性的任务,将是未来大气汞研究的重要内容之一,对于深入理解RGM在大气汞循环过程中的作用具有重要的意义。

共价有机框架在水中二价汞吸附去除中的应用

伴随现代工业的迅速发展,大量含汞化合物通过多种途径进入水环境。二价汞离子(Hg^(2+))是水体中汞的主要存在形态,开发先进的水体Hg^(2+)去除技术对于降低健康风险和保障生态安全至关重要。作为有效的水处理技术之一,吸附法去除水中的Hg^(2+)已得到了人们的关注,而寻找性能优异的吸附材料是取得突破的关键。近年来,共价有机框架(Covalent organic frameworks,COFs)凭借其高比表面积、有序的多孔结构和表面易功能化等优势,已被广泛应用于环境修复领域。本文主要综述了COFs在吸附去除水中Hg^(2+)方面的最新进展,探讨COFs的结构设计、功能化合成、水中Hg^(2+)吸附行为、反应机理、环境影响因素以及拓展至规模化应用的潜力,并展望该领域未来发展的新机遇。

生物效应导向的污染物分析研究新进展

与日俱增的化学品污染导致环境形势日益严峻.效应导向分析技术(effect-directed analysis, EDA)是分析复杂基质中效应污染物的实用工具,该方法结合了生物效应测试、有机污染物分离、污染物浓度测定和结构鉴定等分析评价方法.本文综述了近年来EDA在样品提取、生物效应测试、分离制备流程和质谱鉴定方法等方面的最新研究进展.同时,本文介绍了高通量筛选在EDA中的应用,并对EDA未来的研究方向和挑战进行了展望.

Heavy metals in maternal and cord blood in Beijing and their efficiency of placental transfer

This study aimed to determine the effect of exposure to heavy metals in pregnant women in Beijing, China. We also evaluated the association of these heavy metals with birth weight and length of newborns. We measured the levels of 10 heavy metals,including lead(Pb), titanium(Ti), manganese(Mn), nickel(Ni), cadmium(Cd), chromium(Cr), antimony(Sb), stannum(Sn), vanadium(V), and arsenic(As), in 156 maternal and cord blood pairs. An inductively coupled plasma mass spectrometry method was used for measurement. Pb, As, Ti, Mn, and Sb showed high detection rates(> 50%) in both maternal and cord blood. Fourteen(9%) mothers had blood Pb levels greater than the United States Center for Disease Control allowable threshold limit for children(50 μg/L).In prenatal exposure to these heavy metals, there was no significant association between any heavy metal and birth weight/length. Moreover, we estimated the placental transfer efficiency of each heavy metal, and the median placental transfer efficiency ranged from 49.6%(Ni) to 194%(Mn)(except for Cd and Sn). The level and detection rate of Cd in maternal blood were much higher than that in cord blood, which suggested that Cd had difficulty in passing the placental barrier. Prospective research should focus on the source and risk of heavy metals in non-occupationally exposed pregnant women in Beijing.

单细胞水生生物金属纳米颗粒的定量分析

人类活动释放的金属纳米颗粒不可避免地进入水环境中。大量研究表明,金属纳米颗粒会对水生生物产生生殖毒性和遗传毒性等,金属纳米颗粒还可能沿着食物链传递,对环境生物和人类健康造成威胁。细胞内金属纳米颗粒定量分析是研究金属纳米颗粒生物效应的重要基础。此外,单细胞之间存在异质性,具有特殊生理特性的细胞个体可能影响细胞群体的命运。而基于细胞群体平均值的定量分析则忽略了细胞个体的异质性,遗漏了对群落具有重要功能的细胞群体信息。因此,在单细胞水平上定量分析水环境中底层营养级的单细胞微生物细胞内金属纳米颗粒,对认识金属纳米颗粒与水生生物的相互作用,评估其进入食物链的潜在风险至关重要。本文梳理了已用于单细胞水生生物体内金属纳米颗粒的单细胞定量分析方法,阐述了它们的工作原理和在相关研究中的应用,总结了各方法的优缺点,期望为今后相关研究的方法选择提供参考,最后展望了该领域未来的研究方向。

Mercury in alpine fish from four rivers in the Tibetan Plateau

As a global pollutant, high levels of mercury（Hg） have been found in remote ecosystem due to the long range atmospheric transport. In this study, a total of 60 fish samples were collected from four rivers across the Tibetan Plateau to study the accumulation of Hg in remote and high-altitude aquatic environment. The total Hg（THg） and methylmercury（MeHg） in fish muscles ranged from 11 to 2097 ng/g dry weight（dw）（average： 819 ng/g dw）and from 14 to 1960 ng/g dw（average： 756 ng/g dw）, respectively. Significantly positive linear relationships were observed between the THg（r = 0.591, p 〈 0.01, n = 36） and MeHg concentrations（r = 0.473, p 〈 0.01, n = 36） with the trophic level of fish from Lhasa River,suggesting trophic transfer and biomagnification of Hg in this aquatic ecosystem. Moreover,the THg levels in fish had significantly positive correlations with the length（r = 0.316,p 〈 0.05, n = 60） and weight（r = 0.271, p 〈 0.05, n = 60） of fish. The high levels of Hg were attributed to the slow growth and long lifespan of the fish under this sterile and cold environment. Risk assessment revealed that the consumption of Oxygymnocypris stewartii,Schizothorax macropogon, Schizothorax waltoni, Schizopygopsis younghusbandi and Schizothorax o＇connori would lead to a high exposure to Me Hg.

Decreasing mercury levels in consumer fish over the three decades of increasing mercury emissions in China

Fish consumption is the primary dietary route of human exposure to methylmercury.It has been well documented that elevated mercury concentration in fish in North America and Europe is linked to anthropogenic mercury emissions.China is the world’s largest producer,consumer,and emitter of mercury,as well as the world’s largest commercial fish producer and consumer.Although mercury pollution in fish in China is currently receiving much attention worldwide,its status remains largely unknown.Here,we conducted a meta-analysis on total mercury concentrations in marine and freshwater fish samples,covering 35,464 samples collected in China over the past 30 years.It is found that,opposite to the increasing emission and documented mercury contamination events,mercury levels in fish have gradually decreased in China over the past 30 years.The results were in sharp contrast to those found in North America and Europe.The mercury concentrations in fish were significantly anticorrelated with the fish catch and fish aquaculture and were inverse to trophic levels.Overfishing and the short lifecycle of aquaculture fish,both reducing the trophic level and the duration of mercury accumulation,were the most likely causes leading to the decline of mercury concentrations found in fish in China.