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探讨活性氧(reactive oxygen species,ROS)在温石棉激活线粒体通路诱导A549凋亡中的作用。采用不同浓度温石棉粉尘染毒人肺上皮细胞(A549)后,MTT法检测细胞存活率,流式细胞术检测ROS抑制剂N-乙酰半胱氨酸(N-acetyl-L-cysteine,NAC)预处理前后的细胞凋亡率、胞内ROS水平及线粒体膜电位,Western Blot法检测各组细胞半胱天冬氨酸蛋白酶3(caspase-3)、p53蛋白表达水平。实验结果显示,温石棉可降低A549细胞存活率,呈现时间-剂量效应关系;NAC可显著减少胞内ROS水平、阻止线粒体膜电位下降,并下调caspase-3、p53蛋白的表达水平,抑制部分细胞凋亡的发生。表明ROS可通过诱导p53蛋白过表达,激活线粒体凋亡通路,诱导A549细胞发生凋亡。 相似文献
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以活性MgO和纳米SiO2为原料,在仿地质作用的碱性水热环境下控制不同反应参数合成了多个系列的纤蛇纹石样品。利用XRD和IR分析系统地研究了不同反应参数对纤蛇纹石特征的影响。结果表明,活性MgO和纳米SiO2在水热环境中很容易转变成纤蛇纹石相,但形成完善纳米管结构须严格控制水热反应条件;pH值、反应温度和反应时间的提高均有利于水热合成结晶度及管状结构更加完善的纤蛇纹石,最佳水热反应条件为pH=13.8,200℃,反应60h,此条件下无其它杂质产物生成,合成温度较前人采用的300℃有所降低。利用SEM和AFM对最佳反应条件下合成的纤蛇纹石纳米管的形貌进行了观察,发现其为短柱状,准直性较高,表面光洁无杂质,直径均一,约50nm,长度多为400～500nm。 相似文献
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Abstract Serpentinite bodies in the Kurosegawa Belt are mapped along fault boundaries between the Cretaceous Sanchu Group (forearc basin-fill sediments) and the rocks of the Southern Chichibu Belt (Jurassic to Early Cretaceous accretionary prism) in the northwestern Kanto Mountains, central Japan. The serpentinites were divided into three types based on microtextures and combinations of serpentine minerals: massive, antigorite and chrysotile serpentinites. Massive serpentinite retains initial pseudomorphic textures without any deformation after serpentinization. Antigorite serpentinite exhibits shape-preferred orientation of antigorite replacing the original lizardite and/or chrysotile to form pseudomorphs. It has porphyroclasts of chromian spinel, and is characterized by ductile deformation under relatively high-pressure–temperature conditions. Chrysotile serpentinite shows evidence for overprinting of pre-existing serpentinite features under shallow, low-temperature conditions. It exhibits unidirectional development of chrysotile fibers. Foliations in antigorite and chrysotile serpentinites strike parallel to the elongate direction of the serpentinite bodies, suggesting a continuous deformation during solid-state intrusion along the fault zones after undergoing complete serpentinization at deeper levels (lower crust and upper mantle). 相似文献
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探讨了我国四大矿区天然温石棉致大鼠肺部损伤作用及肺组织中HO-1和HSP-70的表达差异。从我国四大天然矿区采集4种天然温石棉,用扫描电镜、红外光谱和X射线荧光光谱分析其粉尘形貌、表面活性基团和化学组分。将90只初断乳SPF级Wistar大鼠,随机分为5组(甘肃阿克塞、青海茫崖、四川新康、陕西陕南温石棉组和生理氯化钠溶液阴性对照组),用2. 0 mg/m L温石棉粉尘悬液0. 5 m L(1次/月)对大鼠非暴露式气管内滴注染毒。于1、6、12个月分批处死大鼠6只,测定支气管肺泡灌洗液(BALF)中的乳酸脱氢酶(LDH)、碱性磷酸酶(AKP)和总蛋白(TP)含量,采用qRT-PCR检测肺组织中血红素氧化合酶1(HO-1)和热休克蛋白70(HSP-70) mRNA表达水平,采用western blot检测肺组织中HO-1和HSP-70蛋白表达水平。结果显示,阿克塞、茫崖和新康温石棉组LDH及各温石棉组AKP和TP在各时间点均比阴性对照组高(P 0. 05),且随染毒时间延长呈上升趋势(P 0. 05)。染毒1月时,各染毒组HO-1、HSP-70 mRNA和HO-1、HSP-70蛋白表达量比阴性对照组高(P 0. 05);染毒6月时,各染毒组比阴性对照组高,阿克塞和陕南温石棉组低于茫崖和新康温石棉组(P 0. 05);染毒12月时,阿克塞和陕南温石棉组高于茫崖和新康温石棉组(P 0. 05),茫崖和新康温石棉组低于阴性对照组。 相似文献
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The nature and transport of the fine‐grained component of Swift Creek Landslide,Northwest Washington
Extreme sedimentation in Swift Creek, located in the Cascades foothills in NW Washington (48°55′N, 122°16′W), results from erosion of the oversteepened, unvegetated toe of a large (55 hectares) active landslide. Deposition of landslide‐derived sediment has necessitated costly mitigation projects in the channel including annual dredging and temporary sediment traps in an attempt to reduce the risk of flooding and damage to man‐made structures downstream. This study attempts to understand the process of sediment production along with the corresponding erosion rates of the sediment source to help with the development of mitigation plans and construction of optimal sediment reservoirs. The bedload and suspended sediment in the creek are a direct result of the weathering process of the serpentinitic bedrock underlying the landslide. The serpentinite does not weather to smectite clay, as previously thought. Instead, it weathers to asbestiform chrysotile with minor amounts of chlorite, illite and hydrotalcite, all of which occur in clay seeps on the unvegetated surface of the landslide. The chrysotile fibers average 2 µm in length and make up at least 50%, by volume, of the suspended load transported in Swift Creek. This study does not address the environmental or health implications of the asbestiform chrysotile transport or deposition. During the sampled time between February 2005 and February 2006, 127 discrete suspended sediment samples were collected and discharge was measured 66 times. The suspended sediment concentrations ranged from 0·02 g L?1 to 41·6 g L?1 and the discharge ranged from 0·0 m3 s?1 to 0·5 m3 s?1. A nonlinear functional model estimated the total suspended sediment flux from detailed precipitation records and discrete suspended sediment concentration and discharge measurements to be 910 t km?2 yr?1. When the suspended sediment flux is coupled with estimates of downstream deposition of coarse sediment, the estimated erosion rate for the entire Swift Creek landslide is 158 mm yr?1. The majority of the material entering Swift Creek is presumed to originate on the unvegetated toe of the landslide, for which the erosion rate is thus approximately 1 m yr?1. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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通过FT-IR和XRD对四川新康、陕西陕南、甘肃阿克塞和青海茫崖四大矿区温石棉的物相成分、谱学特征进行测试分析,利用MTT法、流式细胞术检测了4种温石棉纤维粉尘染毒A549细胞后的细胞存活率、凋亡率和细胞周期分布,比较和探讨了四大矿区温石棉纤维粉尘抑制细胞增殖能力的大小及其对细胞凋亡和周期阻滞的影响。研究结果显示,四大矿区温石棉的主要物相是斜纤蛇纹石,新康温石棉成分比其他3种温石棉的复杂,阿克塞和茫崖温石棉的成分相似;四大矿区的温石棉化学基团基本相同,阿克塞和茫崖温石棉纤维的表面结构较陕南和新康温石棉的完善。4种温石棉均能不同程度地抑制A549细胞增殖,诱导细胞凋亡和周期阻滞:茫崖组凋亡率最大(22. 56±2. 56)%,陕南组凋亡率最小(19. 57±3. 07)%;细胞周期阻滞均以G2/M期阻滞为主,新康、陕南、阿克塞和茫崖组处于G2/M期细胞比例分别增加8. 90%、8. 58%、9. 13%和10. 44%。4种温石棉导致细胞凋亡和周期阻滞的能力:茫崖新康阿克塞陕南。 相似文献
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广西陆川蛇纹石玉的岩相结构及成矿机理 总被引：3，自引：2，他引：1
应用外束质子激发X射线荧光光谱法、X射线衍射、激光拉曼光谱、扫描电子显微镜等无损分析技术,对广西陆川蛇纹石玉的成分、物相和结构进行分析。X射线衍射结果显示样品的衍射峰主要位于0.724、0.456、0.362、0.248、0.153和0.150 nm处,表明陆川蛇纹石玉主要矿物成分是蛇纹石,同时伴生方解石矿物与蛇纹石形成穿插交织结构。成矿机理分析表明,陆川蛇纹石玉是由白云质大理岩热液交代作用形成的,和广东的信宜玉均属于富镁碳酸盐型蛇纹石。拉曼光谱显示叶蛇纹石的特征峰位于229、376、457、686和1046 cm-1处,纤蛇纹石的特征峰位于228、345、386、624、690和1102 cm-1处,通过激光拉曼光谱可以快速区分陆川蛇纹石玉中纤蛇纹石和叶蛇纹石两种不同结构的蛇纹石亚种。 相似文献
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采用XRF、XRD和SEM对阿克塞红柳沟矿区的石棉尾矿进行了矿物学特征分析,并进行了制备含硅、镁系列化合物的开发研究。结果表明: 3个矿山石棉尾矿样品的主要化学组成为SiO2 37.01%～39.35%,MgO 37.00%～38.92%,其次是TFe2O3 6.02%～8.37%,烧失量为12.29%～13.56%;主要矿物组成为蛇纹石,且含少量滑石、磁铁矿、水镁石、菱镁矿。石棉尾矿经酸浸获得硫酸镁,制备了"卡房状"氢氧化镁、片状碱式碳酸镁及"卡房状"氧化镁粉体;石棉尾矿的酸浸渣经碱浸获得偏硅酸钠,制备了球状纳米级白炭黑。研究结果对阿克塞红柳沟矿区的石棉尾矿的资源化利用和环境保护具有一定的理论和实际意义。 相似文献
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使用可循环的NH4Cl 溶液作为中间媒介获取Mg2+用于CO2 矿物封存是一种新兴工艺,但是纤蛇纹石在NH4Cl 溶液中较
低的Mg2+浸出率却是这项工艺发展的瓶颈。针对这一问题,本文采用灼烧处理对纤蛇纹石进行改性。结果表明, 灼烧处理
可以有效改变纤蛇纹石中Mg2+反应活性。在600℃灼烧后,所得产物与NH4Cl 反应的转化率达到55.64%,比灼烧前提高了
约43%。600℃灼烧处理脱除了纤蛇纹石外羟基,增大了矿物的反应表面积和具反应活性的Mg2+的量,促进了其与NH4Cl 的
反应 ;脱除内羟基后,具反应活性Mg2+减少,与NH4Cl 反应的转化率降低。 相似文献