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1.
金属毒性研究(Ⅱ)   总被引:12,自引:3,他引:9  
利用细胞生物学技术从定量和定性两个方面探讨了Cr(Ⅲ ) ,Cr(Ⅵ ) ,Ni,Al,Ag和V金属离子对生命组织的毒性作用。研究中发现 ,Cr(Ⅵ )对细胞DNA ,RNA合成限制最为显著 ,Ni和V金属离子在同等水平上妨碍RNA合成 ,随着离子浓度增加 ,Cr(Ⅲ )离子对细胞DNA及RNA限制增大。Al离子对RNA合成限制大于对DNA合成。Ag离子对细胞DNA ,RNA合成限制作用相同。细胞谷胱甘肽 (GSH)还原能力强 ,是细胞最重要的解毒物质 ,也是细胞中防御毒性物质最关键的物质。细胞GSH还原能力定量分析表明 :微量的Cr(Ⅵ )即可导致细胞GSH下降。金属Ni离子破坏细胞骨架 ,使细胞内信息传递受阻 ,亦表现较强毒性。  相似文献   

2.
目的:研究丹酚酸A对脂毒性诱导的H9C2心肌细胞损伤的改善作用并初步探究其分子机制。方法:采用棕榈酸体外诱导建立H9C2心肌细胞脂毒性模型并给予丹酚酸A进行干预,采用乳酸脱氢酶法检测细胞损伤,采用细胞增殖-毒性检测试剂盒检测细胞存活率,采用罗丹明123染色观察心肌细胞线粒体膜电位变化,采用蛋白免疫印迹技术研究丹酚酸A改善作用的分子机制。结果:浓度为400 μmol/L的棕榈酸可显著导致H9C2心肌细胞脂毒性损伤(P<0.05)。不同浓度(10、20、40、80 μmol/L)丹酚酸A暴露对心肌细胞无毒性作用(P>0.05)。丹酚酸A干预显著改善脂毒性诱导的心肌细胞损伤及细胞线粒体膜电位降低(P<0.05)。激活Toll样受体4(Toll-like receptors, TLR4)可显著增强脂毒性诱导的心肌细胞损伤(P<0.05),而抑制TLR4显著减轻棕榈酸诱导的细胞脂毒性(P<0.05)。此外,丹酚酸A显著抑制棕榈酸诱导的TLR4及其下游c-Jun氨基末端激酶(c-Jun N-terminal kinase, JNK MAPK)(P<0.05)。 结论:丹酚酸A改善脂毒性诱导的心肌细胞损伤,该保护作用可能与其抑制TLR4/JNK MAPK信号通路有关。  相似文献   

3.
采用十六烷基三甲基溴化铵(CTAB)作为表面活性剂修饰羧基化的单壁碳纳米管(SWNT-COOH/CTAB),并对原始单壁碳纳米管(SWNTs)与羧基化修饰的单壁碳纳米管(SWNT-COOH)进行材料学特征比较。通过细胞活力和细胞凋亡实验对SWNTs、SWNT-COOH和SWNT-COOH/CTAB的细胞毒性进行比较。结果表明,羧基化修饰的单壁碳纳米管比原始单壁碳纳米管的毒性小,单壁碳纳米管经羧基化后其毒性降低;浓度及时间曲线显示SWNT-COOH/CTAB的毒性与表面活性剂CTAB相关,CTAB和 SWNT-COOH/CTAB的细胞毒性在低浓度范围内(0.5-25μg/mL)是可接受的。十六烷基三甲基溴化铵修饰的羧基化单壁碳纳米管在低浓度范围(0.5-25μg/mL)内可以较安全地用于生物医学领域。  相似文献   

4.
各种金属的细胞相容性金属种植体对人体的影响有局部反应和全身反应.局部反应有种植体周围组织的局部坏死和炎症反应,全身反应有由港出物造成的循环器官障碍、过敏反应和致癌性等.纯金属对细胞的接触毒性以钒、钢、钴、汞等为最强,锗、钛、钥、袒、铂、金等是生物相容性好的元素.有机锡有较强的毒性,但却无任何无机锡有毒的报道.机离子对细胞增殖率的影响较大,而离子溶出量小的钛、锗、锡、铝、钽对L929细胞和骨原性MC3T3-E1细胞的影响却几乎没有.铝对L929细胞的影响,根据苹取条件的不同而不同,同时含有饥高于时,对细胞的影…  相似文献   

5.
目的:研究阿魏酸对棕榈酸诱导的HepG2肝细胞脂毒性的保护作用并初步探究其分子机制。方法:采用棕榈酸诱导HepG2肝细胞建立脂毒性模型并给予阿魏酸进行干预,采用LDH法检测细胞损伤,采用MTT法检测细胞存活率。采用Western Blotting技术对阿魏酸保护作用的分子机制进行研究。结果:不同浓度(25、50、100、200 μmol/L)阿魏酸暴露对肝细胞无毒性作用(P>0.05)。阿魏酸干预显著抑制棕榈酸诱导的肝细胞损伤并改善棕榈酸诱导的细胞线粒体膜电位降低(P<0.05)。激活p38可显著增强棕榈酸诱导的肝细胞脂毒性(P<0.05),而抑制p38显著改善棕榈酸诱导的细胞损伤(P<0.05)。此外,阿魏酸显著抑制棕榈酸上调的p38磷酸化(P<0.05),采用p38激活剂处理细胞可阻断阿魏酸对脂毒性的保护作用(P<0.05)。 结论:阿魏酸可有效改善脂毒性诱导的肝细胞损伤,该保护作用可能与其抑制p38信号通路有关。阿魏酸可能成为防治以脂毒性为主要病理特征性肝病的功效因子。  相似文献   

6.
使用乙二胺改性的木屑黄原酸盐对水溶液中的Cu(II)、Ni(II)离子进行吸附。在单离子体系中,考虑影响因素(温度、投加量)对Cu(II)、Ni(II)单离子吸附等温线的影响;并计算Cu(II)、Ni(II)离子吸附的热力学参数:吸附吉布斯自由能(△GΘ)、吸附过程的焓变(△HΘ)以及熵变(△SΘ),表明此吸附是一个放热自发的过程。在 Cu(II)和Ni(II)双离子体系中,采用修正后的拓展Langmuir模型对体系的吸附情况可以进行很好的预测。在单离子体系和双离子体系中,吸附过程的数据均可通过准二级动力学模型进行描述;计算得到其对Cu(II)和Ni(II)单离子的吸附活化能分别为59.12和55.92 kJ/mol。结果表明,金属离子在改性木屑表面的吸附效果会受到另一离子存在的影响。  相似文献   

7.
张文喜  高未  赵佳佳  蔡俏  赵蓓  郑妍 《金属学报》2018,23(2):194-198
目的: 探讨红霉素对解脲支原体肺炎的疗效及对细胞亚群、肝功能的影响。方法: 收集我院2016年5月至2017年5月收治的41例解脲支原体肺炎患儿作为试验组,静脉滴注10 mg/kg红霉素与适量5%葡萄糖注射液,每天2次,疗程7~10 d,同期选取41例健康体检儿童,比较健康组与试验组治疗前后细胞亚群及肝功能,并分析试验组疗效及安全性。结果: 治疗前,试验组CD4+、CD4+/CD8+分别为(41.95±5.71)%、1.26±0.18,低于健康组的(48.13±7.21)%、1.79±0.20,试验组CD8+为(35.10±4.41)%,高于健康组的(26.56±3.13)%,试验组谷丙转氨酶、乳酸脱氢酶、总胆汁酸、胆红素、总胆固醇、甘油三酯、谷草转氨酶、谷丙转氨酶/谷草转氨酶分别为(136.71±17.20)U/L、(439.67±54.45)U/L、(28.39±3.72)U/L、(68.05±8.95)μmol/L、(7.82±0.95)mmol/L、(1.70±0.24)mmol/L、(113.37±14.25)U/L、1.24±0.14,高于健康组的(45.26±4.88)U/L、(397.98±47.20)U/L、(22.24±2.66)U/L、(36.71±4.83)μmol/L、(4.26±0.46)mmol/L、(1.24±0.17)mmol/L、(62.51±9.19)U/L、0.77±0.12;治疗后,试验组CD4+、CD4+/CD8+显著上升,CD8+、谷丙转氨酶、乳酸脱氢酶、总胆汁酸、胆红素、总胆固醇、甘油三酯、谷草转氨酶、谷丙转氨酶/谷草转氨酶显著下降,且两组比较无统计学差异(P>0.05)。结论: 红霉素对解脲支原体肺炎的疗效肯定,能够利于细胞亚群及肝功能的缓解。  相似文献   

8.
考察萃取剂Versatic 10以及它和Cyanex 301组成的复配萃取体系从含有镁钙离子的硫酸盐溶液中萃取分离镍钴离子的萃取和反萃特征。Versatic 10萃取分离镍钴和钙镁的最佳条件为初始pH值为2.5、油水体积比O/A为1/3、皂化率为60%。Versatic 10的负载有机相用2 mol/L的硫酸溶液以O/A为1/1进行反萃。复配萃取体系中Versatic 10和Cyanex 301的最佳体积比为7/3,复配体系能有效降低镍钴和钙镁萃取分离的平衡pH值至3.50,当O/A为1/2时,2 mol/L的硫酸溶液可以对负载有机相进行有效反萃。Versatic 10与金属离子进行萃取的反应机理为离子交换,而Cyanex 301与金属离子之间不仅有离子交换还有强烈的配位效应,这种配位效应在复配体系与金属离子萃取过程中被大大削弱。  相似文献   

9.
对吸附在高庙子(GMZ)膨润土上的Cr(III)进行解吸实验,研究振荡时间、解吸溶液离子强度、温度和pH值等因素对解吸特性的影响规律。结果表明:高庙子膨润土上Cr(III)的解吸过程较易发生;Cr(III)的解吸动力学过程较吸附过程慢,实验条件下解吸过程在3 h后达到平衡;当使用0.1 mol/L HCl、1 mol/L NaCl和1 mol/L CaCl 2作为解吸液时,Cr(III)的最终解吸率分别达89.4%,56.5%和77.2%;增大解吸溶液的离子浓度能够促进解吸过程的发生;pH值对Cr(III)解吸过程有重要影响;吸附/解吸过程较符合Freundlich等温模型。GMZ膨润土在处理Cr(III)废水时具有较好的再生能力,可以多次重复利用。  相似文献   

10.
污染土修复常采用固化稳定化技术。固化稳定化重金属污染土在酸侵蚀条件下其重金属离子会重新溶出,从而导致对周边环境的二次污染。以常用的水泥、粉煤灰和石灰为固化剂原料,设计不同组合及配比的固化剂,通过无侧限抗压强度试验及硫酸/硝酸法毒性浸出试验研究固化重金属污染土在酸侵蚀条件下的强度及浸出特性。探讨固化剂类型、硫酸盐浓度(1.5,3.0,6.0 g/L)和侵蚀龄期(0,7,14,28 d)对固化重金属污染土的强度及溶出浓度的影响,并引入固定率参数,进一步量化考察侵蚀龄期和侵蚀浓度对重金属离子固定率的影响。结果表明:重金属离子的浸出量随着硫酸盐侵蚀浓度和侵蚀龄期的增加而增加;相对而言,含氧化钙的固化剂对重金属污染土的固化效果较差,重金属离子浸出量大,固化率低。  相似文献   

11.
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.  相似文献   

12.
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.  相似文献   

13.
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.  相似文献   

14.
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.  相似文献   

15.
Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.  相似文献   

16.
On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes' collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.  相似文献   

17.
The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.  相似文献   

18.
On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.  相似文献   

19.
A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.  相似文献   

20.
Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.  相似文献   

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