Effects of Subchronic Aluminum Exposure on Amino Acids Neurotransmitters in Chicken Brain

To investigate the effects of aluminium （Al） exposure on amino acid neurotransmitters, the chickens with different levels of subchronic Al poisoning were estabolished by continuous peritoneal injection of fixed volume and different concentrations of gradient of aluminium trichloride （AlCl3）. The levels of amino acid neurotransmitters in chicken brains were determined by high performance liquid chromatography （HPLC） after being exposed of Al for 60 days, and Al levels in serum and brain tissue were determined by atomic absorption spectrophotometry （AAS）. The results showed that Glu levels increased with the increase of Al, but there was no significant difference compared with the control. The levels of Al, Asp, Gly, GABA and Tau were significantly higher in Al-treated groups than those in the control. The results indicated that Al intoxication led to excitatory neurotoxicity.

Effects of Sub-chronic Aluminum Exposure on Renal Pathologic Structure in Rats

A total of 40 Wistar rats, weighing 130-140 g, were allocated randomly into four groups. They were orally administrated with 0 （control group, GC）, 64.18 （low-dose group, GL）, 128.36 （middle-dose group, GM）, and 256.72 （high-dose group, GH） mg aluminum chloride （AlCl3） per kilogram body weight in drinking water for 120 days. Kidney coefficient and aluminum （Al） concentrations in blood and kidney were determined, and renal autopsy and histological changes were observed. The results showed that kidney coefficient in all Al-treated groups were obviously lower than that in GC （P〈0.01） and there was a dose-effect relationship. The kidneys were solid, lusterless and pale brown with white necrosis point on surface. Under electron microscope, renal cortex became thin, the renal tubule was narrowed and the epithelium dissolved; the renal glomerulus became atrophied and the glomerular became vasodilator. The Al concentrations in blood and kidney were higher in all Al-treated rats than those in GC （P〈0.01）, and there was a dose-effect relationship. The results indicated that sub-chronic Al exposure could lead to Al accumulation in kidney, restrain the development of kidney and cause the pathologic damage in rats.

Effect of long-term thermal exposure on microstructure and creep properties of DD5 single crystal superalloy

The effect of thermal exposure on the microstructure and creep properties of the Ni-based single crystal superalloy in different test conditions was studied.Long-term exposure was performed at 1,000 ℃ and 1,100 ℃ for 500 h prior to the creep tests.The creep lifetime is found to be improved after the long-term exposure at 1,000 ℃ for 500 h as a result of the formation of secondary M_(23)C_(6) in the interdendritic region.The coarsening of γ’ precipitates accompanied by the formation of TCP phase lead to the degradation of alloy,which is responsible for the reduction of the creep lifetime of Ni-base single crystal superalloy after long-term exposure at 1,100 ℃ for 500 h.The creep lifetime of 1,000 oC thermally exposed sample under the conditions of 1,093 ℃/137 MPa is lower than that of heat-treated state.Thermal exposure at 1,100 ℃ for 500 h causes the creep lifetime to drop drastically.

TEM study on microstructures and properties of 7050 aluminum alloy during thermal exposure

The microstructures of 7050 aluminum alloy under different thermal exposure conditions were investigated by means of transmission electron microscopy(TEM),high resolution electron microscopy(HREM)and tensile test.Guinier preston(GP)zone andη′phase are the main precipitates in original 7050 alloy.The orientation relationship betweenη′and matrix is Al [0001]η′//[111] andA l (1010)η′//(110).When the alloy is exposed at different temperatures for 500 h,with the thermal exposure temperature increasing,it can be seen under TEM that the precipitates become larger and the width of precipitate free zones(PFZ)becomes larger. The higher temperature the alloy is exposed at,the more the strength is reduced.Both GP zones andη′precipitates getting coarser and the PFZ getting wider should be responsible for the strength decline and elongation rise of 7050 alloy during thermal exposure.

Effect of hot-humid exposure on static strength of adhesive-bonded aluminum alloys

The effect of hot-humid exposure(i.e., 40 C and 98% R.H.) on the quasi-static strength of the adhesive-bonded aluminum alloys was studied. Test results show that the hot-humid exposure leads to the significant decrease in the joint strength and the change of the failure mode from a mixed cohesive and adhesive failure with cohesive failure being dominant to adhesive failure being dominant. Careful analyses of the results reveal that the physical bond is likely responsible for the bond adhesion between L adhesive and aluminum substrates. The reduction in joint strength and the change of the failure mode resulted from the degradation in bond adhesion, which was primarily attributed to the corrosion of aluminum substrate. In addition, the elevated temperature exposure significantly accelerated the corrosion reaction of aluminum, which accelerated the degradation in joint strength.

Long-term ocean temperature trend and marine heatwaves

Marine heatwaves(MHWs)can cause irreversible damage to marine ecosystems and livelihoods.Appropriate MHW characterization remains difficult,because the choice of a sea surface temperature(SST)temporal baseline strongly influences MHW identification.Following a recent work suggesting that there should be a communicating baseline for long-term ocean temperature trends(LTT)and MHWs,we provided an effective and quantitative solution to calculate LTT and MHWs simultaneously by using the ensemble empirical mode decomposition(EEMD)method.The long-term nonlinear trend of SST obtained by EEMD shows superiority over the traditional linear trend in that the data extension does not alter prior results.The MHWs identified from the detrended SST data exhibited low sensitivity to the baseline choice,demonstrating the robustness of our method.We also derived the total heat exposure(THE)by combining LTT and MHWs.The THE was sensitive to the fixed-period baseline choice,with a response to increasing SST that depended on the onset time of a perpetual MHW state(identified MHW days equal to the year length).Subtropical areas,the Indian Ocean,and part of the Southern Ocean were most sensitive to the long-term global warming trend.

Effects of Subchronic Aluminum Exposure on Liver Function in Rats

Effects of subchronic aluminum （Al） exposure on the function of rat liver were investigated in this experiment. A total of 48 male Wistar rats （4 weeks old） were randomly divided into four groups： experimental groups were orally exposed to 64.18, 128.36, 256.72 mg. kg^-1 body weight aluminum trichloride （AlCl3） in drinking water, and the control group with distilled water. The experiment lasted for 120 days. The activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-PX）, the concentration of malondialdehyde （MDA） in serum and liver, and alanine transarninase （ALT） and aspartate aminotransferase （AST） activities in serum were detected in all groups. The results showed that the activities of ALT, AST in serum and the concentrations of MDA in liver in the Al-treated groups significantly increased compared with the control group; the activities of GSH-PX and SOD in high-dose Al-treated group were significantly lower than those in control group. Our findings indicated that subchronic AI exposure could result in injures of lipid peroxidation and function in liver.

Microstructure and mechanical properties of the pressure die cast magnesium alloy AZ91D after long-term thermal exposure

The thermal resistance of the pressure die cast magnesium alloy AZ91D is yet not investigated sufficiently. Inorder to assess the effect of a thermal exposure on the microstructural stability and the mechanical properties, the alloyAZ91D is subjected to a long-term annealing for 1 000 h at 80 °C, 100 °C, 120 °C, 150 °C, 180 °C and 200 °C. After theannealing, the microstructural appearance of the material is investigated by light and scanning electron microscopy andcompared with the as-cast condition. Furthermore, tensile tests, hardness measurements and fracture toughness tests arecarried out and the measured values are discussed on the basis of the microstructural changes. The results reveal thedistinct correlation between the microstructural changes, especially the precipitation of discontinuous and continuousβ-particles (Mg17 Al12), and the mechanical properties.

A Bayesian network for estimating hypertension risk due to occupational aluminum exposure

Background The correlation between metals and hypertension,such as sodium,zinc,potassium,and magnesium,has been confirmed,while the relationship between aluminum and hypertension is not very clear.This study aimed to evaluate the correlation between plasma aluminum and hypertension in electrolytic aluminum workers by the Bayesian networks(BN).Methods In 2019,476 male workers in an aluminum factory were investigated.The plasma aluminum concentration of workers was measured by inductively coupled plasma mass spectrometry.The influencing factors on the prevalence of hypertension were analyzed by the BN.Results The prevalence of hypertension was 23.9%in 476 male workers.The risk of hypertension from plasma aluminum in the Q2,Q3,and Q4 groups was 5.20(1.90–14.25),6.92(2.51–19.08),and 7.33(2.69–20.01),respectively,compared with that in the Q1 group.The risk of hypertension from the duration of exposure to aluminum of>10 years was 2.23(1.09–4.57),compared without aluminum exposure.Area under the curve was 0.80 of plasma aluminum and the duration of exposure to aluminum was based on covariates,indicating that aluminum exposure had important predictive value in the prevalence of hypertension in the occupational population.The results of the study using the BN model showed that if the plasma aluminum of all participants was higher than Q4(≥47.86µg/L)and the participants were drinking,smoking,diabetes,central obesity,dyslipidemia,and aged>50 years,the proportion of hypertension was 71.2%.Conclusions The prevalence of hypertension increased significantly with the increase of plasma aluminum level.

The RAS/PI3K Pathway is Involved in the Impairment of Long-term Potentiation Induced by Acute Aluminum Treatment in Rats

Objective To explore the role of RAS/PI3K pathway in the impairment of long-term potentiation （LTP） induced by acute aluminum （AI） treatment in rats in vivo. Methods First, different dosages of aluminum-maltolate complex [Al（mal）3] were given to rats via acute intracerebroventricular （i.c.v.） injection. Following AI exposure, the RAS activity of rat hippocampus were detected by ELISA assay after the hippocampal LTP recording by field potentiation technique in vivo. Second, the antagonism on the aluminum-induced suppression of hippocampal LTP was observed after the treatment of the RAS activator epidermal growth factor （EGF）. Finally, the antagonism on the downstream molecules （PKB activity and the phosphorylation of GluR1 $831 and $845） were tested by ELISA and West-blot assays at the same time. Results With the increasing aluminum dosage, a gradually decreasing in RAS activity of the rat hippocampus was produced after a gradually suppressing on LTP. The aluminum-induced early suppression of hippocampal LTP was antagonized by the RAS activator epidermal growth factor （EGF）. And the EGF treatment produced changes similar to those observed for LTP between the groups on PKB activity as well as the phosphorylation of GluR1 S831 and s845. Conclusion The RAS-PI3K/PKB-GluR1 S831 and S845 signal transduction pathway may be involved in the inhibition of hippocampal LTP by aluminum exposure in rats. However, the mechanisms underlying this observation need further investigation.

Effect of Aluminum on Long-Term Potentiation and Its Relation to L-arg-No-pathway in Hippocampal CA3 Area of Rats

Experiments were performed on 64 Sprague-Dawley rats under ure-thane anesthesia. Extracellular recording method was used to investigate the effect of aluminum (Al)microinjected into CA3 on long-term potentiation (LTP) in this area. The relationship between the inhibitory effect of Al and L-arginine-NO pathway was also studied. Microinjection of Al (0. 5 mol/L, 1 μl ) into CA3 could block the induction of LTP in CA3. Microinjection of Al (0. 5 mol/L, 1 μl) into CA3 after LTP was induced could also decrease the amplitude of population spike (PS). The inhibitory effect of Al on LTP in CA3 could be enhanced by preinjection of NG-nitro-L-arginine (0. 3 mol/L, 1 μl). Preinjection of L-arginine (0. 3 mol/L, 1 μl) into CA3 could antagonize the inhibitory effect of Al on LTP. These results suggest that Al could block the induction of LTP and decrease the amplitude of PS potentiated in CA3. The effect of Al might be antagonized by L-arginine-NO pathway.

生姜提取物对染铝毒大鼠学习记忆功能和神经细胞结构的影响及其可能作用机制

目的分析生姜提取物(GRE)对铝染毒大鼠学习记忆功能及神经细胞结构的影响,并基于钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)、神经元型一氧化氮合酶(nNOS)、蛋白激酶C(PKC)探讨其可能的作用机制。方法将36只SD雄性大鼠随机分为空白对照组、铝染毒组、临床药物组、低剂量GRE(L⁃GRE)组、中剂量GRE(M⁃GRE)组、高剂量GRE(H⁃GRE)组,每组6只大鼠。空白对照组大鼠自由饮用不含氯化铝的饮用水,其余组大鼠饮用含10 mg/mL结晶氯化铝的饮用水。3个月后给予空白对照组和铝染毒组大鼠灌胃生理盐水,临床药物组大鼠灌胃盐酸多奈哌齐溶液,分别给予L⁃GRE组、M⁃GRE组、H⁃GRE组大鼠灌胃100 mg/kg、200 mg/kg、400 mg/kg GRE溶液。持续干预4周后,采用Morris水迷宫实验评估大鼠的学习记忆功能,通过HE染色观察大鼠海马组织形态变化,分别采用实时荧光定量PCR和Western blot检测大鼠海马组织CaMKⅡ、nNOS、PKC mRNA和蛋白表达水平。结果(1)与空白对照组相比,铝染毒组大鼠的逃避潜伏期延长且穿越平台次数减少(P<0.05),海马组织的神经细胞皱缩,神经细胞数量明显减少,CaMKⅡ、nNOS、PKC的mRNA表达水平及nNOS、PKC的蛋白表达水平降低(P<0.05)。(2)与铝染毒组比,L⁃GRE组、M⁃GRE组和H⁃GRE组大鼠的逃避潜伏期缩短,临床药物组、M⁃GRE组、H⁃GRE组大鼠的穿越平台次数增加(P<0.05);各给药组大鼠海马组织病理形态有不同程度的改善;临床药物组大鼠的CaMKⅡ、nNOS和PKC mRNA表达水平升高,各剂量GRE组大鼠nNOS和PKC mRNA和蛋白表达水平升高(P<0.05)。(3)与临床药物组相比,M⁃GRE组和H⁃GRE组大鼠的逃避潜伏期,以及各剂量GRE组的穿越平台次数和目标象限停留时间差异无统计学意义(P>0.05);各剂量GRE组大鼠海马组织病理形态改善程度更为明显;M⁃GRE组、H⁃GRE组大鼠的nNOS、PKC蛋白表达水平升高,L⁃GRE组大鼠的nNOS蛋白表达水平升高(P<0.05)。(4)各剂量GRE组组间大鼠逃避潜伏期、穿越平台次数及目标象限停留时间差异无统计意义(P>0.05);随GRE干预剂量增加,大鼠海马组织病理形态的改善效果越明显;H⁃GRE组大鼠的CaMKⅡmRNA表达水平高于L⁃GRE组(P<0.05)。结论GRE能够改善铝染毒大鼠的神经细胞结构和学习记忆功能,其中对神经细胞结构的改善效果优于盐酸多奈哌齐,对学习功能的改善效果与盐酸多奈哌齐相当。GRE的作用机制可能与拮抗铝所致CaMKⅡ、nNOS和PKC表达水平下降有关。

Long-term exposure to air pollution and cerebrovascular disease:findings from Beijing Health Management Cohort study

The relationship between air pollution and cerebrovascular disease has become a popular topic,yet research findings are highly heterogeneous.This study aims to investigate this association based on detailed individual health data and a precise evaluation of their exposure levels.The integrated models of generalized additive model,land use regression model and back propagation neural network were used to evaluate the exposure concentrations.And doubly robust additive model was conducted to explore the association between cerebrovascular disease and air pollution after adjusted for demographic characteristics,physical examination,disease information,geographic and socioeconomic status.A total of 25097 subjects were included in the Beijing Health Management Cohort from 2013 to 2018.With a 1µg/m^(3)increase in the concentrations of PM_(2.5),SO_(2)and NO_(2),the incidence risk of cerebrovascular disease increased by 1.02(95%CI:1.008–1.034),1.06(95%CI:1.034–1.095)and 1.02(95%CI:1.010–1.029)respectively.Whereas CO exposure could decrease the risk,with an odds ratio of 0.38(95%CI:0.212–0.626).In the subgroup analysis,individuals under the age of 50 with normal BMI were at higher risk caused by PM2.5,and So2 was considered more hazardous to women.Meanwhile,the protective effect of CO on women and those with normal BMI was stronger.Successful reduction of long-term exposure to PM2.5,SO_(2)and NO_(2)would lead to substantial benefits for decrease the risk of cerebrovascular disease especially for the health of the susceptible individuals.

Corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands tropical marine atmosphere

The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),and electrochemical impedance spectroscopy(EIS).The results indicated that serious pitting corrosion occurred on the surfaces of pure aluminum.The corrosion rate after exposure for 13 months was approximately 1.28 g/(m^(2)·a).The XPS results showed that the corrosion products were Al_(2)O_(3),Al(OH)_(3),and AlCl_(3).Moreover,the corrosion product layer was more protective than the native oxide film,and the protectiveness first increased and then decreased.Finally,the shape of the pits was evaluated using statistical analysis.

Effects of Aluminum Toxicity Induced by Acid Deposition on Pine Forest Ecosystem in Longli of Guizhou Province, Southwestern China

The effects of acid deposition on pine forest ecosystems in Longli of Guizhou Province, southwestern China are studied using indoor experiments and model simulations. Indoor experiments are designed to explore the aluminum toxicity on pine seedlings, and the long-term soil acidification model （LTSAM） and a terrestrial biogeochemistry model （CENTURY） are used to simulate the influences of acid deposition on pine forest ecosystems. The indoor experiment results of aluminum toxicishow that aluminum ions in solution limit plant growth and acid deposition enhances this effect by facilitating the release of aluminum ions from the soil. Pine seedling bio- mass and root elongation decrease as the aluminum concentration increases. The results of model simulations show that the soil chemis- try varies significantly with different changes in acid deposition. When the acid deposition increases, the pH value in the soil solution decreases and the soil A13＋ concentration increases. The increased acid deposition also has negative impacts on the forest ecosystem, i.e., decreases plant biomass, net primary productivity （NPP） and net C02 uptake. As a result, the soil organic carbon （SOC） decreases be- cause of the limited supply of decomposition material. Thus acid deposition need be reduced to help protect the forest ecosystems.

miR-125a-5p通过黏着斑通路对铝染毒GC2-spd细胞凋亡的影响

目的 探讨miR-125a-5p在铝染毒小鼠精母细胞系(GC2-spd)模型中对黏着斑信号通路及GC2-spd细胞凋亡的影响。方法 建立铝染毒GC2-spd细胞模型,分为对照组(CG),铝染毒组(ALG),铝染毒组+miR-125a-5p inhibitor阴性对照组(ALG+inhibitor NC)及铝染毒组+miR-125a-5p inhibitor组(ALG+inhibitor);利用RT-qPCR检测ALG与CG细胞中miR-125a-5p的表达情况;利用Western blot检测CG组、ALG组、ALG+inhibitor NC组及ALG+inhibitor组Itga7、Pak4、Akt1、Bax及Caspase-9的表达情况;利用CCK8实验及流式细胞术实验检测各组GC2-spd细胞的活性和凋亡率。结果 RT-qPCR结果显示,与对照组比较,ALG组细胞中miR-125a-5p的表达显著升高;Western blot结果显示,抑制miR-125a-5p的表达后,可显著升高铝染毒GC2-spd细胞中Itga7、Pak4和Akt1的表达,降低Bax及Caspase-9的表达;CCK8和流式细胞术实验结果显示,抑制miR-125a-5p的表达后,可显著提高GC2-spd细胞的活性,降低细胞的凋亡率。结论 miR-125a-5p inhibitor可通过提高Itga7、Pak4和Akt1的表达,促进黏着斑信号通路激活,抑制细胞凋亡,提高细胞的活性,从而抑制铝染毒GC2-spd细胞的凋亡作用。

海南省部分市县市售面制品中铝污染现状研究及膳食暴露评估

为调查海南省部分市县市售面制品中铝污染现状,并评估海南省居民的铝暴露情况,采集海南省6个市县(琼海市、琼中县、定安县、儋州市、文昌市、昌江市)市售面制品共200份,根据国家标准方法采用电感耦合等离子体质谱仪(ICP-MS)进行分析测定,并结合2009年海南省居民营养与健康状况调查结果,评估面制品中铝的暴露量。结果显示,200份面制品中铝的检出率为90.5%,其中油炸类、焙烤类面制品的铝超标率分别为6%和2%。通过对海南省6个市县市售面制品进行抽样检测发现,面制品中铝污染现象已有较大改善,海南省居民从面制品中摄入的铝含量对人体健康危害较小。

Excess mortality associated with high ozone exposure:A national cohort study in China

Emerging epidemiological studies suggest that long-term ozone(O_(3))exposure may increase the risk of mortality,while pre-existing evidence is mixed and has been generated predominantly in North America and Europe.In this study,we investigated the impact of long-term O_(3)exposure on all-cause mortality in a national cohort in China.A dynamic cohort of 20882 participants aged
40 years was recruited between 2011 and 2018 from four waves of the China Health and Retirement Longitudinal Study.A Cox proportional hazard regression model with time-varying exposures on an annual scale was used to estimate the mortality risk associated with warm-season(Aprile September)O_(3)exposure.The annual average level of participant exposure to warm-season O_(3)concentrations was 100 mg m^(-3)(range:61 e142 mg m^(-3)).An increase of 10 mg m^(-3)in O_(3)was associated with a hazard ratio(HR)of 1.18(95%confidence interval[CI]:1.13e1.23)for all-cause mortality.Compared with the first exposure quartile of O_(3),HRs of mortality associated with the second,third,and highest exposure quartiles were 1.09(95%CI:0.95e1.25),1.02(95%CI:0.88e1.19),and 1.56(95%CI:1.34e1.82),respectively.A J-shaped concentration eresponse associationwas observed,revealing a non-significant increase in risk below a concentration of approximately 110 mg m^(-3).Low-temperature-exposure residents had a higher risk of mortality associated with long-term O_(3)exposure.This study expands current epidemiological evidence from China and reveals that high-concentration O_(3)exposure curtails the long-term survival of middle-aged and older adults.

热暴露对7A85铝合金微观组织和力学性能的影响

选用7A85-T74锻造铝合金为实验材料,研究室温至240℃内热暴露5 h后的合金微观组织、拉伸性能及冲击吸收能量,并结合透射电子显微镜分析微观组织对合金力学性能的影响机理。结果表明:在80~240℃热暴露温度范围内,7A85-T74铝合金晶粒尺寸变化不大,但沉淀相随温度升高有显著变化;在120℃以内,随热暴露温度的升高,析出物尺寸、拉伸性能和冲击吸收能量整体变化不大,沉淀强化机制为位错切过析出物和位错绕过析出物的混合机制;随着热暴露温度由120℃升高至240℃,析出物的平均半径由室温下的3.8 nm增加至12.3 nm,析出物由η'相向η相转变,合金的屈服强度和抗拉强度显著下降,较室温分别下降45.7%和33.5%,伸长率、断面收缩率和冲击吸收能量显著升高,沉淀强化机制转变为位错绕过析出物,断裂方式由沿晶断裂和韧窝型穿晶断裂组成的混合断裂转变为韧窝型穿晶断裂。基于沉淀强化理论讨论析出物尺寸对合金强度与冲击吸收能量的影响,理论分析结果与实验结果相符。

典型阳极氧化铝合金在热带海洋大气环境下的腐蚀行为研究

在文昌热带海洋大气环境下对经过硫酸阳极氧化的2A12、6061和7050铝合金进行48个月的长期大气暴露试验,根据腐蚀动力学,宏观和微观腐蚀形貌演变,以及腐蚀产物形貌和成分分析,研究了它们的腐蚀行为。结果表明,3种铝合金硫酸阳极氧化试样的腐蚀形式主要为点蚀,表面会出现不规则的颗粒腐蚀产物,随着暴露时间延长而逐渐形成一些大块的疏松、有裂纹的腐蚀产物,主要是Al_(2)O_(3)和AlO(OH)。在这个过程中,点蚀坑不断从阳极氧化膜表面发展到铝合金基体。3种试样的腐蚀失重与暴露时间的关系均符合幂函数规律,腐蚀速率较小,说明硫酸阳极氧化膜对铝合金基体有较好的保护作用。与6061和7050铝合金硫酸阳极氧化试样相比,硫酸阳极氧化2A12铝合金的腐蚀更为严重。