Particulate matter (PM2.5) exposure season-dependently induces neuronal apoptosis and synaptic injuries

Epidemiological studies have shown that particulate matter 2.5 (PM_2.5) not only increases the incidence of cardiopulmonary illnesses but also relates to the development of neurodegenerative diseases. Considering that PM_2.5 is highly heterogeneous with regional disparity and seasonal variation, we investigated whether PM_2.5 exposure induced neuronal apoptosis and synaptic injuries in a season-dependent manner. The results indicated that PM_2.5 altered the expression of apoptosis-related proteins (mainly bax and bcl-2), activated caspase-3 and caused neuronal apoptosis. Additionally, PM_2.5 decreased the levels of synaptic structural protein postsynaptic density (PSD-95) and synaptic functional protein N-methyl-D-aspartate (NMDA) receptor subunit (NR2B) expression. These effects occurred in a season-dependent manner, and PM_2.5 collected from the winter showed the strongest changes. Furthermore, the effect was coupled with the inhibition of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) and phosphorylated cAMP-response element binding protein (p-CREB). Based on the findings, we analyzed the correlations between the chemical composition of PM_2.5 samples and the biological effects, and confirmed that winter PM_2.5 played a major role in causing neuronal apoptosis and synaptic injuries among different season samples.     

Endocannabinoid 2-arachidonoylglycerol protects inflammatory insults from sulfur dioxide inhalation via cannabinoid receptors in the brain

Sulfur dioxide(SO_2) pollution in the atmospheric environment causes brain inflammatory insult and inflammatory-related microvasculature dysfunction.However,there are currently no effective medications targeting the harmful outcomes from chemical inhalation.Endocannabinoids(eCBs) are involved in neuronal protection against inflammation-induced neuronal injury.The 2-arachidonoylglycerol(2-AG),the most abundant eCBs and a full agonist for cannabinoid receptors(CB1 and CB2),is also capable of suppressing proinflammatory stimuli and improving microvasculature dysfunction.Here,we indicated that endogenous 2-AG protected against neuroinflammation in response to SO_2 inhalation by inhibiting the activation of microglia and astrocytes and attenuating the overexpression of inflammatory cytokines,including tumor necrosis factor alpha(TNF-a),interleukin(IL)-1β,and inducible nitric oxide synthase(iNOS).In addition,endogenous 2-AG prevented cerebral vasculature dysfunction following SO_2 inhalation by inhibiting endothelin 1(ET-1),vascular cell adhesion molecule-1(VCAM-1) and intercellular adhesion molecule 1(ICAM-1) expression,elevating endothelial nitric oxide synthase(eNOS) level,and restoring the imbalance between thromboxane A2(TXA2) and prostaglandin 12(PGI2).In addition,the action of endogenous 2-AG on the suppression of inflammatory insult and inflammatory-related microvasculature dysfunction appeared to be mainly mediated by CB1 and CB2 receptors.Our results provided a mechanistic basis for the development of new therapeutic approaches for protecting brain injuries from SO_2 inhalation.     

Abnormal energy metabolism and tau phosphorylation in the brains of middle-aged mice in response to atmospheric PM2.5 exposure

In light of the accelerated aging of the global population and the deterioration of the atmosphere pollution, we sought to clarify the potential mechanisms by which fine particulate matter (PM_2.5) can cause cognitive impairment and neurodegeneration through the alteration of mitochondrial structure and function. The results indicate that PM_2.5 inhalation reduces ATP production by disrupting the aerobic tricarboxylic acid cycle and oxidative phosphorylation, thereby causing the hypophosphorylation of tau in the cortices of middle-aged mice. Furthermore, excessive reactive oxygen species generation was involved in the impairment. Interestingly, these alterations were partially reversed after exposure to PM_2.5 ended. These findings clarify the mechanism involved in mitochondrial abnormality-related neuropathological dysfunction in response to atmospheric PM_2.5 inhalation and provide an optimistic sight for alleviating the adverse health outcomes in polluted areas.     

水力停留时间对MFC-A2/O工艺处理生活污水的影响

在10 L的A~2/O反应器中构建微生物燃料电池(MFC)系统,以厌氧段作为阳极室去除有机物,缺氧段作为阴极室去除硝酸盐.结果发现,30 d左右可以达到最大输出电流.系统启动后进入稳定期对水力停留时间(HRT)进行优化,结果表明,当HRT=16 h时可以获得最佳出水效果,此时MFC的出水COD、总氮浓度分别比对照A~2/O反应器低14.6%和10.1%,在100Ω外阻下的输出功率密度为612 m W·m~(-3);当HRT=12 h时,产电效果最好,最大输出功率密度可以达到808 m W·m~(-3).     

PM2.5暴露对小鼠肝脏能量代谢的影响

通过细颗粒物(particulate matter 2.5,PM_(2.5))的暴露,探讨其对小鼠肝脏能量代谢方式的影响及作用机制.采用透射电镜(TEM)观察肝脏组织中线粒体超微结构的改变,并检测了三磷酸腺苷(ATP)、丙酮酸和乳酸含量的变化,同时用实时荧光定量-聚合酶链式反应(RT-PCR)检测糖酵解相关基因果糖-2,6-二磷酸酶(PFKFB3)和乳酸脱氢酶(LDHB)及三羧酸循环(TCA)相关基因丙酮酸脱氢酶(PDHA1)、柠檬酸合成酶(CS)和延胡索酸酶(FH)的表达情况.此外,还对活性氧(ROS)的水平进行检测.结果表明,PM_(2.5)暴露对小鼠肝脏组织中的线粒体造成损伤,导致ATP的下降,丙酮酸和乳酸的积累.此外,PDHA1、CS和FH的表达明显降低,PFKFB3和LDHB的表达显著升高,这些结果共同表明PM_(2.5)改变了小鼠肝脏的能量代谢方式.同时ROS水平明显升高,表明PM_(2.5)暴露可能是通过ROS抑制三羧酸循环,增强糖酵解方式来为机体提供能量,从而对肝脏的能量代谢产生影响.     

二氧化硫及其衍生物对大鼠心肌细胞胶原蛋白表达的影响

以100μmol·L~(-1)亚硫酸氢钠对H9C2心肌细胞染毒不同时间(3,6,12,24 h),采用Wistar大鼠作为模型进行整体动物染毒,SO_2组动式吸入SO_2(7 mg·m~(-3))28 d,每天4 h;SO~(2+)NALC(N-乙酰半胱氨酸)组吸入同样条件的SO_2,且自SO_2染毒之日起隔天腹腔注射50 mg·kg-1(b.w.)NALC,对照组吸入新鲜空气并注射生理盐水.测定大鼠心脏组织和H9C2细胞内ROS含量;采用荧光定量PCR和Western blot分析I型胶原(Col1a1)和III型胶原(Col3a1)的mRNA转录和蛋白表达水平.结果显示SO_2及其衍生物引起的氧化应激显著增加了活性氧(ROS)的产生;SO_2及其衍生物不能诱导大鼠心脏组织和H9C2细胞中Col1a1和Col3a1 mRNA转录水平的显著改变,但Col1a1和Col3a1的蛋白表达水平显著升高;同时NALC可减少心脏组织中ROS的产生,有效抑制SO_2吸入后Col1a1和Col3a1蛋白表达的上升.提示SO_2吸入后可能通过产生ROS最终导致胶原蛋白表达的增加.     

满江红对不同形态铀的吸附行为

首先采用Visual MINTEQ 3.1软件模拟了不同pH及不同浓度的碳酸盐或磷酸盐溶液中不同形态铀所占的比例;随后根据模拟结果,配制了5种分别含有UO_2~(2+)、(UO_2)_3(OH)_5~+、UO_2(OH)_3~-、UO_2(CO_3)_3~(4-)和UO_2PO_4~-的铀溶液;最后通过水培实验研究了满江红对这5种不同形态铀的吸附行为.结果表明,这5种不同形态铀对满江红的生长抑制率有显著差异,UO_2~(2+)、(UO_2)_3(OH)_5~+、UO_2(OH)_3~-及UO_2(CO_3)_3~(4-)均能抑制满江红的生长,其中,UO_2~(2+)对满江红的生长抑制率最高,而UO_2PO_4~-则可以促进满江红的生长,但满江红对UO_2~(2+)和(UO_2)_3(OH)_5~+的吸附效率相对较高.当溶液中铀的浓度为2 mg·L~(-1)时,UO_2~(2+)对满江红的富集量和富集系数分别达到了3831 mg·kg~(-1)和1916,(UO_2)_3(OH)_5~+对满江红的富集量和富集系数分别达到了3057 mg·kg~(-1)和1529.可见,要提高满江红对水中铀的去除率和富集量,应将溶液中铀的形态调控为以UO_2~(2+)或(UO_2)_3(OH)_5~+为主,同时要降低溶液中碳酸盐和磷酸盐的含量.     

湿电除尘器PM2.5现场实测与特征变化研究

基于稀释通道原理自设固定源PM2.5稀释采集系统,应用该系统对陕西省关中地区某燃煤电厂湿式电除尘器(WESP)进出口烟气中的PM2.5、PM10和颗粒物开展了现场实测,并在实验室对采集样品进行了化学源组分分析。结果表明:WESP对PM2.5、PM10和颗粒物的脱除效率分别为67.85%、43.57%、40.88%;WESP前后质量浓度峰值均出现在积聚模态,但由双峰(1.764μm、0.649μm)变成单峰(1.764μm),峰值移至大粒径段,数浓度峰值出现在爱根核模态和积聚模态,但由多峰(0.017μm、0.129μm、0.384μm、1.764μm)变成双峰(0.017μm、0.073μm),峰值移至小粒径段;经WESP,PM2.5积聚模态大多粒径段颗粒物的质量浓度与数浓度均在下降,爱根核模态大多粒径段颗粒物的质量浓度与数浓度均在上升,无论是WESP前或后,PM2.5的主要质量浓度均集中在大粒径段、主要数浓度均集中在小粒径段;WESP对PM2.5中大粒径段颗粒物的去除效果要优于小粒径段颗粒物;WESP对PM2.5中全部已检出离子和大部分主要无机元素均具有去除作用,占离子总质量比重最高的SO42-和占元素总质量比重第5位的Mg去除率均最高(64.75%,接近100%);经WESP处理后,各检出离子的质量浓度大小排序未受任何影响(由大到小为SO4^2-、Na^+、Ca^2+、Cl^-、NO3^-、F^-、Mg^2+、NO2^-、NH4^+、K^+)。     

道路生态影响评价方法研究：以兰海高速公路为例

提出了将道路生态影响问题划分为3个尺度来进行评价,并根据不同尺度的生态特征采用不同的方法和指标,从而系统、定量的评价道路建设和运行所带来的生态影响.小尺度问题采用野外调查和样方对比的方法;中尺度问题主要依靠不同分辨率的遥感监测,辅之野外调研;大尺度问题主要依靠遥感和GIS结合进行分析.以兰海高速公路为例,运用该系统进行评价,取得了良好的结果.因此,该体系方法可以作为道路生态影响评价和研究的借鉴和参考.     

Graphitic carbon nitride-based photocatalysts in the applications of environmental catalysis

Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution problems. The key issue is the development of high-efficiency photocatalysts. Various strategies in the state-of-the-art advancements, such as heterostructure construction, heteroatom doping, metal/single atom loading, and defect engineering, have been presented for the graphitic carbon nitride (g-C₃N₄)-based nanocomposite catalysts to design their surface chemical environments and internal electronic structures to make them more suitable for different photocatalytic applications. In this review, nanoarchitecture design, synthesis methods, photochemical properties, potential photocatalytic applications, and related reaction mechanisms of the modified high-efficiency carbon nitride-based photocatalysts were briefly summarized. The superior photocatalytic performance was identified to be associated with the enhanced visible-light response, fast photoinduced electron-hole separation, efficient charge migration, and increased unsaturated active sites. Moreover, the further advance of the visible-light harvesting and solar-to-energy conversions are proposed.