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1.
任翠翠  牛金平 《精细化工》2012,29(8):738-741,782
合成了壬基酚聚氧丙烯聚氧乙烯醚磺酸盐(NPESO-3-4),采用高效液相色谱法检测了目标产物中原料的含量,同时测定了其表面张力、乳化能力、润湿性及模拟驱油率并与壬基酚聚氧乙烯醚磺酸盐的性能(NPESO-0-4)做了比较。结果表明:与NPESO-0-4相比,NPESO-3-4水溶液降低表面张力的能力略低,但降低表面张力的效率较高。二者与胜利孤东原油之间的界面张力均在10-1 mN?m-1数量级,但NPESO-3-4能将油性表面润湿反转为中间润湿,乳化能力和模拟驱油率明显高于NPESO-0-4,说明含氧丙烯链节的阴-非离子表面活性剂在三次采油中有很好的应用价值。  相似文献   

2.
Inhibition of lipid peroxidation and nonlipid oxidative damage by carnosine   总被引:3,自引:0,他引:3  
The antioxidant effects of carnosine on lipids and nonlipids, including liposomes, carbohydrates, and proteins, were investigated. Carnosine exhibited a remarkable antioxidant effect in liposome and deoxyribose model systems. Carnosine at high amounts (50 mg/mL) was effective in protecting protein against oxidation. The correlation coefficients between reducing ability and the inhibition of liposome, albumin, and deoxyribose oxidation were r=0.92, 0.83, and 0.41, respectively. Carnosine exhibited metal-binding ability and scavenging ability for hydroxyl radicals generated by photolysis of H2O2 with UV light. The correlation coefficients between hydroxyl radical scavenging and the inhibitory effect on deoxyribose, liposome, and albumin oxidative damage were r=0.97, 0.60, and 0.29, respectively. These properties may explain how carnosine protects lipids and non-lipids against oxidative damage.  相似文献   

3.
This study investigated the behaviour of aluminium and carbon steel electrodes in the presence and absence of nonylphenol ethoxylates (NPnEO, where n is the number of ethoxylate groups in the molecule) and NPnEO removal by electrochemically-generated coagulants. The electrode processes were studied by potentiodynamic polarization measurements to determine the influence of surfactant addition (ethylene oxide units and organic load), inorganic composition and pH. The polarization curves showed the extent of the involvement of NPnEO in the electrode processes. Their influence appeared clearly in the range of anodic activation, depending on the number of ethoxylate groups. Removal of NPnEO from simulated wastewaters was carried out in two electrocoagulation cells with vertical and horizontal electrodes, respectively. The removal efficiencies calculated from the chemical oxygen demand before and after treatment were 30–50% for NP16EO and NP40EO, and 40–80% for NP4EO. The hydrophilic-lipophilic balance number for NP4EO indicated a relative ratio of polar and non-polar groups lower than for the other two surfactants, which was in favour of better NP4EO removal. The experiments showed the processes in the bulk (bridging of electrochemically-generated polymeric species and adsorption of surfactants) were predominant over the involvement of NPnEO in the electrode processes, which were only responsible for the electrogeneration of coagulants.  相似文献   

4.
采用倒置生物显微镜观察人皮肤成纤维细胞(HSF)的形态,通过MTT法检测细胞存活率,并通过检测细胞内活性氧(ROS)水平、总抗氧化能力和抗氧化酶活性探讨天然椰子油提取物对H_2O_2诱导的HSF细胞氧化损伤的保护作用。结果表明,天然椰子油提取物在质量浓度为12.5~50 mg/L范围内对H_2O_2诱导的HSF细胞氧化损伤具有保护作用,且呈浓度依赖性。天然椰子油提取物可以抑制H_2O_2引起的细胞形态损伤,提高细胞存活率,还可以通过降低细胞内ROS水平、提高细胞总抗氧化能力以及提高细胞内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性,进而起到保护HSF细胞氧化应激损伤的作用。  相似文献   

5.
6.
Pyrethrins are a class of potent insecticides produced byChrysanthemum cinerariaefolium. Simulated herbivory does not affect concentrations of pyrethrins in damaged and undamaged expanding and fully expanded leaves, or flowers of greenhouse or field-grown plants.  相似文献   

7.
8.

Background  

Some manufactured nanoparticles are metal-based and have a wide variety of applications in electronic, engineering and medicine. Until now, many studies have described the potential toxicity of NPs on pulmonary target, while little attention has been paid to kidney which is considered to be a secondary target organ. The objective of this study, on human renal culture cells, was to assess the toxicity profile of metallic nanoparticles (TiO2, ZnO and CdS) usable in industrial production. Comparative studies were conducted, to identify whether particle properties impact cytotoxicity by altering the intracellular oxidative status.  相似文献   

9.
The analysis of the chemiluminescence (CL) kinetic parameters (induction time, oxidation rate, and activation energy) after the UV irradiation and outdoor exposure of isotactic polypropylene (i‐PP) films have been studied. The initial CL emission intensity increased with increasing photodegradation time of i‐PP films. On photodegradation, the activation energies were found to decrease linearly with time of UV‐irradiation and outdoor exposure. The slopes of these linear dependences were used to indicate the degree of photodegradation of the polymer and also for the characterization of the stabilizing effect of the additive. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4623–4629, 2006  相似文献   

10.
The constituent lipids of plasma and red blood cells (RBC) from mice late in infection with the malarial parasitePlasmodium vinckei were analyzed and compared with those obtained from uninfected animals. On a dry weight basis, the total extractable lipids of RBC increased three-fold during infection, while those of the plasma did not change significantly. In general, changes in individual plasma lipid constituents paralleled those found in RBC of infected mice but were of smaller magnitude. While the increase in the total lipids of parasitized RBC was largely attributable to an increase of more than fourfold in total phospholipids, a significant increase in neutral lipids was also observed. Phosphatidylcholine and phosphatidylethanolamine were the major phospholipids present within RBC, and their total and relative concentrations increased as a result of the infection. A parallel increase occurred in the ratio of unsaturated to saturated fatty acids in the parasitized RBC phospholipids. Infection was also associated with decreases in the relative amount of cholesterol present in RBC and in the ratio of cholesterol to phospholipid. Consistent with this, the fluorescence polarization of 1[4-(trimethylamino)phenyl]-6-phenylhexa-1,3,5-triene within parasitized RBC plasma membranes was decreased in comparison with its value in noninfected RBC, indicating that malarial infection decreases the “order” of membrane lipids. These modifications, in conjunction with the increased levels of vitamin E and malonyldialdehyde reported elsewhere, are important determinants of the susceptibility of the different membrane compartments within infected RBC to peroxidative damage.  相似文献   

11.
采用弱极性色谱柱,用面积百分比法进行定量,氢火焰检测器进行检测分析壬基酚及其杂质含量,并验证了该方法的有效性、准确性和可行性.  相似文献   

12.
王玉春  刘赵荣  谭超  孙鸿  李忠 《化工进展》2021,40(1):242-246
以具有升华性质且易分解的乙酰丙酮铜为铜源,NH4Y分子筛为载体,采用蒸气浸渍法制备了CuY催化剂,考察了其对甲醇氧化羰基化合成碳酸二甲酯的催化性能,并采用XRD、H2-TPR和NH3-TPD等表征手段研究了催化剂上铜物种的分散状态、催化活性中心的含量及催化剂的酸强度和浓度,发现铜物种在Y分子筛载体上高度分散,且Y分子筛载体的晶体结构保持完好。在N2∶H2=12∶1的气氛中,250℃还原得到的催化剂CuY/250催化活性中心含量最高,催化活性也达到了最佳,其甲醇转化率为11.1%,碳酸二甲酯的时空收率和选择性分别为200.5mg/(g·h)和60.3%。  相似文献   

13.
Silicon-based quantum dots were intraperitoneally injected in Carassius auratus gibelio specimens and, over one week, the effects on renal tissue were investigated by following their distribution and histological effects, as well as antioxidative system modifications. After three and seven days, detached epithelial cells from the basal lamina, dilated tubules and debris in the lumen of tubules were observed. At day 7, nephrogenesis was noticed. The reduced glutathione (GSH) concentration decreased in the first three days and started to rise later on. The superoxide dismutase (SOD) activity increased only after one week, whereas catalase (CAT) was up-regulated in a time-dependent manner. The activities of glutathione reductase (GR) and glutathione peroxidise (GPX) decreased dramatically by approximately 50% compared to control, whereas the glutathione-S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH) increased significantly after 3 and 7 days of treatment. Oxidative modifications of proteins and the time-dependent increase of Hsp70 expression were also registered. Our data suggest that silicon-based quantum dots induced oxidative stress followed by structural damages. However, renal tissue is capable of restoring its integrity by nephron development.  相似文献   

14.
氧化改性反渗透膜元件的性能及应用   总被引:1,自引:0,他引:1  
提出了废弃反渗透膜经过氧化改性处理得到近似纳滤膜的概念与工艺,分析了氧化膜的各项运行性能指标,明确了氧化膜的运行稳定性、化学稳定性及可清洗特性,列举了氧化膜在膜工艺技术领域中的工程应用环境.  相似文献   

15.
Earth-orbiting hardware operates in environments that generally include neutral particles, charged particles such as trapped protons and electrons, solar protons, cosmic rays, and dilute low energy plasma. Debris from other spacecraft, natural micrometeoroids, direct and reflected solar photons, and thermal radiation and magnetic fields from the earth may each degrade materials. Materials must survive exposure to each of these phenomena in the hard vacuum of the space environment.

The range of earth orbit environments are described and selected aspects of the interactions of materials with the space environment are discussed. Results of examination of materials flown in space on the long duration exposure facility (LDEF) and the passive optical sample assembly (POSA) experiments are used to illustrate the unique effects resulting from exposure to the low-earth orbit environment.  相似文献   


16.
Nonylphenol (NP), stannous octoate [Sn(Otc)2], and a mixture of NP and Sn(Otc)2 were employed for catalyzing cyanate ester resin. The curing reaction was studied by differential scanning calorimetry. A water‐absorption test at 85 °C was utilized to study the resistance to warm and humid conditions. The thermal properties were evaluated through measuring thermal weight loss and the glass‐transition temperature (Tg), and the mechanical properties were evaluated through three‐point bending tests and tensile tests. The results show that the mixture of NP and Sn(Otc)2 exhibits the best catalytic efficiency by decreasing the exothermic peak temperature by almost 148 °C. The mixture of NP and Sn(Otc)2 has unfavorable effects on the thermal stability. Nevertheless, all catalyst systems have good water‐absorption resistance. The mechanical investigation confirms that the tensile properties show a little reduction that is due to the plasticization of the catalyst, while the excellent flexural properties are maintained. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43959.  相似文献   

17.
Yamazaki Y  Zinchenko AA  Murata S 《Nanoscale》2011,3(7):2909-2915
Fluorescent microscopy observation of gene-size DNA (T4 phage DNA or λ phage DNA) was used to assess DNA damage induced by UV irradiation in the presence of nanomaterials, such as QDs (quantum dots: CdSe/ZnS semiconductor nanoparticles), the water-soluble fullerene derivative C(60)(OH)(n) (n = 6-12) and titanium oxide nanoparticles of 25 nm in diameter. The magnitude of DNA damage could be simply evaluated based on the degree of shortening of the stretched DNA image. This method showed that DNA damage was amplified by the action of QDs under irradiation by C-band (λ(max) = 254 nm) or B-band (λ(max) = 303 nm) UV. Smaller QDs that emitted higher-energy fluorescence (λ = 565 nm) induced more severe damage than medium- and larger-size QDs that emitted longer-wavelength fluorescence (λ = 605 and 705 nm, respectively). The fullerene derivative and TiO(2) nanoparticles caused DNA damage even under irradiation by A-band UV (λ(max) = 365 nm) and showed more severe DNA damage than QDs under similar conditions.  相似文献   

18.
J.E. Brocklehurst 《Carbon》1975,13(5):421-424
It is well known that the presence of boron enhances fast neutron irradiation damage in graphite by providing nucleation sites for interstitial loop formation. Doping with B11 causes an increase in the irradiation induced macroscopic dimensional changes, which have been shown to result from an acceleration in the differential crystal growth rate for a given carbon atom displacement rate. Models of irradiation induced creep in graphite have centred around these in which creep is induced by internal stresses due to the anisotropic crystal growth, and those in which creep is activated by atomic displacements. A creep test on boron doped graphite has been performed in an attempt to establish which of these mechanisms is the determining factor. An isotropic nuclear graphite was doped to a boron (B11) concentration of 0.27 wt.%. The irradiation induced volume shrinkage rate at 750°C increased by a factor of 3 over that of the virgin graphite, in agreement with predictions from the earlier work, but the total creep strains were comparable in both doped and virgin samples. This observation supports the view that irradiation induced creep is dependent only on the carbon atom displacement rate and not on the internal stress level determined by the differential crystal growth rate. The implications of this result on the irradiation behaviour of graphite containing significant concentrations of boron are briefly discussed.  相似文献   

19.
Several biochemical parameters of male Wistar rats fed during 15 weeks with standard laboratory chow, supplemented with 0.1 g of brominated vegetable oil (olive, sunflower) per 100 g of diet, were compared to those of a control group fed a normal diet during the same period of time. The former group showed a significant increase of triglyceride content in both heart and soleus muscle, as well as of total and sterified cholesterol in heart muscle. This increase was accompanied by decreased plasma levels of total and HDL-cholesterol. Some of these abnormalities were similar to those observed in rats fed the same standard laboratory chow, supplemented with 0.5 g of brominated oil per 100 g of diet. The hepatic levels of triglycerides, total proteins and glycogen, as well as the weight gain and caloric intake of the animals which were fed 0.1 g of brominated oil per 100 g diet, were similar to those of the control group. In summary, the toxicologic effects observed during the chronic intake of diets supplemented with relatively low doses of brominated oils, suggest the need to undertake wider and deeper biochemical studies. The authors consider that these are necessary in order to ascertain the maximum tolerance levels for the use of these compounds, to minimize the risk of inducing important biological alterations.  相似文献   

20.
Nonylphenol (NP) is an ultimate degradation product of nonylphenol polyethoxylates (NPE) that is primarily used in cleaning and industrial processes. Its widespread use has led to the wide existence of NP in various environmental matrices, such as water, sediment, air and soil. NP can be decreased by biodegradation through the action of microorganisms under aerobic or anaerobic conditions. Half-lives of biodegradation ranged from a few days to almost one hundred days. The degradation rate for NP was influenced by temperature, pH and additions of yeast extracts, surfactants, aluminum sulfate, acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, hydrogen peroxide, heavy metals, and phthalic acid esters. Although NP is present at low concentrations in the environment, as an endocrine disruptor the risks of long-term exposure to low concentrations remain largely unknown. This paper reviews the occurrence of NP in the environment and its aerobic and anaerobic biodegradation in natural environments and sewage treatment plants, which is essential for assessing the potential risk associated with low level exposure to NP and other endocrine disruptors.  相似文献   

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