聚氨酯泡沫塑料吸附-火焰原子吸收光谱法测定铜选矿流程样品中金

在稍开马弗炉炉门的条件下焙烧样品后,采用盐酸、硝酸-氯酸钾溶样,用约0.2g经10%(体积分数,下同)盐酸浸泡24h后的聚氨酯泡沫塑料(简称泡塑)吸附样品中金,以自来水冲洗干净泡塑以去除吸附矿浆,然后直接用王水-高氯酸对泡塑进行消解,建立了泡塑吸附-火焰原子吸收光谱法(FAAS)测定铜选矿流程中金的分析方法。实验表明:高碳、高硫样品在稍开马弗炉炉门的条件下,650℃焙烧3.5h可以将碳处理干净;用0.2g经10%盐酸浸泡24h后的泡塑可将4.0mg金吸附完全;泡塑震荡吸附120min基本可以消除矿浆对吸附率的影响。在选定的实验条件下,金在0.20~1.0μg/mL质量浓度范围内与其对应的吸光度线性良好,相关系数为0.999 8,方法检出限为0.024μg/g。采用实验方法对铜选矿流程中铜原矿、铜精矿、铜尾矿中金进行测定,测定结果与标准方法 GB/T 3884.2—2012或GB/T 20899—2007均较为一致,相对标准偏差(RSD,n=11)不大于10%。     

Aerobic growth on nitroglycerin as the sole carbon, nitrogen, and energy source by a mixed bacterial culture

Nitroglycerin (glycerol trinitrate [GTN]), an explosive and vasodilatory compound, was metabolized by mixed microbial cultures from aeration tank sludge previously exposed to GTN. Aerobic enrichment cultures removed GTN rapidly in the absence of a supplemental carbon source. Complete denitration of GTN, provided as the sole C and N source, was observed in aerobic batch cultures and proceeded stepwise via the dinitrate and mononitrate isomers, with successive steps occurring at lower rates. The denitration of all glycerol nitrate esters was found to be concomitant, and 1, 2-glycerol dinitrate (1,2-GDN) and 2-glycerol mononitrate (2-GMN) were the primary GDN and GMN isomers observed. Denitration of GTN resulted in release of primarily nitrite-N, indicating a reductive denitration mechanism. Biomass growth at the expense of GTN was verified by optical density and plate count measurements. The kinetics of GTN biotransformation were 10-fold faster than reported for complete GTN denitration under anaerobic conditions. A maximum specific growth rate of 0.048 +/- 0.005 h-1 (mean +/- standard deviation) was estimated for the mixed culture at 25 degreesC. Evidence of GTN toxicity was observed at GTN concentrations above 0. 3 mM. To our knowledge, this is the first report of complete denitration of GTN used as a primary growth substrate by a bacterial culture under aerobic conditions.     

改进预处理方法对提高聚氨酯泡沫塑料富集金能力的探讨

根据聚氨酯泡沫塑料的性质,先采用无水乙醇浸泡,再用HCl煮沸的方式对其进行预处理,并通过火焰原子吸收法测定金。实验确定了聚氨酯泡沫塑料在无水乙醇中最佳浸泡时间为4 h,该方法金回收率在95%以上。通过对国家标准物质和实验室控制样品的测定表明,测定结果与推荐值吻合,其相对标准偏差(RSD)为0.58%~3.70%。该方法操作简单,测定结果稳定,能够满足地质样品中金的分析测试要求。     

Shape-dependent effects in a series of aromatic nitro compounds acting as mutagenic agents on S. typhimurium TA98

Freshly isolated hepatocytes of the clawed toad, Xenopus laevis, were cultured for at least 3 days. The viability of the cells was characterized using staining and biochemical methods. In particular, the glucose and glycogen balance was tested. After culture for 16-20 hrs, the cells were subjected to hormonal treatment. Both adrenaline and arginine vasotocin stimulated the release of glucose in a dose dependent manner. 10(-6) M concentrations were strongly effective. The determination of the glycogen balance made it clear that the glucose release is mainly due to glycogenolysis. Using receptor antagonists and agonists, it has been shown that the effect of adrenaline is clearly mediated by beta-type receptors. Arginine vasotocin stimulated glycogenolysis via a type of receptor which is similar to the V2-receptor of mammals. This means that cAMP is involved in the response to both types of hormones which is in contrast to that which is known about the effect of nonapeptides on the liver of mammals.     

气相多环芳烃的吸附净化技术研究进展

多环芳烃（PAHs）是近年来在大气污染问题中逐渐受到关注的一类污染物,不仅其自身严重威胁着人体健康,还可作为低挥发性物质促进二次颗粒物的生长.世界多国开始不断通过各种技术手段对废气中PAHs的排放进行控制,PHAs已成为大气环境领域共同关注的热点问题.吸附法是最具潜力且已被工业应用认可的一类PAHs控制净化关键技术,吸附剂对PAHs的吸、脱附性能是其中的关键.目前国内外学者无论是基于传统碳类吸附剂,还是新型的介孔吸附剂,都针对此类特殊低挥发性气体的吸附相平衡、动力学以及脱附特性做了相关研究,探悉了获取PAHs吸脱附最优平衡的关键因素以及最适吸附剂.本文针对这些结果及相关应用进行了综述,对比分析了介孔吸附剂较传统吸附剂在PAHs吸脱附特性上呈现的优势,旨在为PAHs及其他低挥发性气体吸附净化的相关工作提供有效参考.     

The surface-active compounds of a Pseudomonas sp. S-27 culture

Pseudomonas species S-27 was grown on various substrates. It was established that the Pseudomonas species S-27 strain can produce biosurfactants of ramnolipid nature decreasing the surface and interfacial tension to 29.2 and 0.05 mN/m. respectively, as well as a biopolymer stabilizing the emulsions with hydrocarbons and oils. The biosurfactant and bioemulsifier synthesis is shown to depend of the substrate nature.     

Effect of polyionic compounds on the adsorption of polyoma virus

The aim of this work was to study the hydroxylation by tyrosinase of 4-t-butylphenol to 4-t-butylcatechol, in the presence of hydrogen peroxide. This hydroxylation reaction does not take place without the addition of hydrogen peroxide. Some properties of this new hydroxylating activity have been analysed. The kinetic parameters of mushroom tyrosinase for hydrogen peroxide (K(m) = 4.9 mM, V(m) = 48.1 microM/min) and 4-t-butylphenol (K(m) = 16 microM/min, V(m) = 6.7 microM/min) were evaluated. A lag period appeared, which was similar to the characteristic lag of monophenolase activity at the expense of molecular oxygen. The length of the lag phase decreased with increasing hydrogen peroxide concentrations but was longer with higher 4-t-butylphenol concentrations. The pH optimum for this hydroxylating activity was close to 5.5. The lag also varied with pH, reaching its highest value at pH 4.8. The lag was shortened by the addition of increasing amounts of 4-t-butylcatechol, and was abolished at 24.5 microM of 4-t-butylcatechol. 4-t-Butylphenol was oxidized by mushroom tyrosinase in the presence of 24.5 microM 4-t-butylcatechol and in the absence of hydrogen peroxide although the enzymatic activity tailed off. The presence of hydrogen peroxide is necessary to maintain a constant steady-state rate of 4-t-butylphenol oxidation by tyrosinase.     

Pathway engineering for the production of aromatic compounds in Escherichia coli

The standard enzymatic assay for quantification of D-sorbitol in plasma was adapted to the automatic analyzer Cobas Mira S. In the assay, NAD (reagent) in the presence of sorbitoldehydrogenase (SDH; start reagent) converts D-sorbitol to fructose with formation of NADH, which was detected automatically as the difference between the first and last readings at 340 nm. The sample blank values for each specimen were subtracted to exclude both endogenous D-sorbitol and sugars, which also react as substrates for SDH. The method is simple, rapid (40 samples/h), precise down to endogenous concentrations (coefficient of variation < 5%; limit of determination: 0.38 mg/L) and linear up to 100 mg/L. Samples with higher D-sorbitol concentrations were estimated after dilution. The method was used to measure disposition curves of sorbitol in volunteers after a single intravenous dose of 0.8 g sorbitol.     

氰化浸金活性炭吸附金容量的研究

根据黄金行业自身特点,模拟黄金提取过程中的氰化浸金环境,研究活性炭吸附金能力的测定方法.通过实验确定活性炭类型为椰壳炭,并对影响因素进行了优化,确定最佳条件为活性炭粒度200目,吸附液中氰化钠质量分数为0.05%,体积为150 mL,pH值为11.5,吸附时间为16 h,温度为(25±1)℃,振荡器转速为200 r/min.该方法测定结果的相对标准偏差为3.81%,准确度为95.20%~99.98%,为黄金行业直接、客观评价活性炭吸附金能力提供可靠方法.     

活性炭吸附金的初步研究

本文介绍美国研究活性炭从矿浆中吸附金的方法和设备,以及我们采用该方法所取得的研究成果。其中包括活性炭的种类及其用量的确定;金的吸附速率和金的平衡吸附曲线;以及炭浆法和炭浸法的比较。     

Bacterial community dynamics during start-up of a trickle-bed bioreactor degrading aromatic compounds

Phosphatidylinositol 3-kinase (PI3K) is a heterodimer lipid kinase consisting of an 85-kD subunit bound to a 110-kD catalytic subunit that also possesses intrinsic, Mn(2+)-dependent protein serine kinase activity capable of phosphorylating the 85-kD subunit. Here, we examine the Mn(2+)-dependent protein kinase activity of PI3K alpha immunoprecipitated from normal resting or thrombin-stimulated platelets, and characterize p85/p110 phosphorylation, in vitro. Phosphoamino acid analysis of phosphorylated PI3K alpha showed p85 and p110 were phosphorylated on serine, but in contrast to previous results, were also phosphorylated on threonine and tyrosine. Wortmannin and LY294002 inhibited p85 phosphorylation; however, p110 phosphorylation was also inhibited suggesting p110 autophosphorylation on serine/threonine. The protein tyrosine kinase inhibitor, erbstatin analog, partially inhibited p85 and p110 phosphorylation but did not appear to affect PI3K lipid kinase activity. The in vitro phosphorylation of p85 alpha or p110 alpha derived from thrombin-stimulated platelets was no different than that of resting platelets, but we confirm that in thrombin receptor-stimulated platelets enhanced levels of p85 alpha and PI3K lipid kinase activity were recovered in antiphosphotyrosine antibody immunoprecipitates. These results suggest PI3K alpha can autophosphorylate on serine and threonine, and both p85 alpha and p110 alpha are substrates for a constitutively-associated protein tyrosine kinase in platelets.     

Pseudomonas aeruginosa as a cause of infectious diarrhoea

Pseudomonas aeruginosa is not generally considered a cause of infectious diarrhoea. However, it was the predominant organism isolated from the faeces of 23 unrelated, hospital outpatients investigated in the course of a year for persistent (> 1 week duration) diarrhoea. To investigate the possible aetiological role of P. aeruginosa, these patient histories were reviewed and a selection of their faecal isolates were investigated in vitro (n > or = 10) and in vivo (n = 2) for virulence. The patients had a mean age of 60 years, were receiving antibiotics and/or had an underlying illness. Extensive microbiological investigations identified no other potential or recognized enteropathogen in the faeces of 20 of these patients. More than 40% of the isolates tested were able to adhere to HEp-2 cells and exhibited twitching motility (type IV pili), properties indicative of their ability to colonize the human intestine. Cytotoxic activity was demonstrated in bacterium-free cell supernatants of over 80% of isolates; supernatants of four isolates tested in infant mice were weakly enterotoxigenic. Two isolates intragastrically inoculated into clindamycin pre-treated rats established persistent infections and induced signs and symptoms of enteritis. Overall these findings suggest that P. aeruginosa can cause diarrhoea particularly in immunodeficient individuals.     

The liver as a source of somatomedin

Somatomedin (Sm) activity (measured by [35S] utake in chick embryo cartilage) was determined in serum samples simultaneously drawn from the hepatic vein, portal vein, femoral artery and demoral vein of seventeen anaesthezied normal adult dogs). A pool of human serum was taken as reference (Sm = 1 U/ml). Sm levels in the peripheral vein of dogs were 0.38 +/- 0.03 U/ml). Mean +/- SEM). Sm activity was greater in the hepatic vein (0.48 U/ml) than in the other vessels (0.36, 0.39, 0.38 U/ml), and the paired differences were significant (P less than 0.002 to P less than 0.05). In three dogs which received b-GH (20 IU/day), the Sm levels were significantly increased after nine days in the femoural vein (P less than 0.05) and in the hepatic vein (P less than 0.05). The validity of the assay is discussed; a possible interference of NEFA in the assay is eliminated. The difference of Sm levels between hepatic and portal veins, related to hepatic flow measured in seven of these dogs, indicate an important production of Sm by the liver.     

钪-钙-茜素红异多核络合物在碳纳米管修饰碳糊电极上的吸附伏安法研究

制备了多壁碳纳米管修饰碳糊电极并研究了钪-钙-茜素红异多核络合物在该电极上的吸附伏安行为,提出了采用二阶导数线性扫描伏安法测定痕量钪的新方法。在0.08 mol/L氨基乙酸-0.04 mol/L邻苯二甲酸氢钾缓冲溶液(pH3.6)中,在0 mV富集90 s后,从0~1 000 mV以200 mV/s的速率线性扫描,络合物吸附在修饰电极表面,于-544 mV(vs.SCE)处产生一灵敏的溶出峰,为络合物中配体茜素红的还原所产生。二阶导数峰高与钪的浓度在6.0×10-12~4.0×10-7mol/L范围内分3段呈良好的线性关系,检出限(S/N=3)为4.0×10-12mol/L(富集时间180 s)。方法用于岩矿样品中痕量钪的测定,测定结果同ICP-AES法的测定结果相一致。     

The reversibility of adsorption of gold cyanide on activated carbon

Much controversy exists about the mechanism by which gold cyanide adsorbs on activated carbon. It is not the purpose of this article to explain the exact adsorption mechanism but, rather, to investigate the factors affecting the reversibility of adsorbed gold cyanide. Whereas Au(CN) ₂ ⁻ is soluble in water, AuCN and Au require the addition of cyanide to form Au(CN) ₂ ⁻ . The reversibility of the adsorption of gold onto carbon is a function of the nature of the adsorbed gold and determines the need for cyanide in the elution process, which affects the operating costs of a carbon-in-pulp (CIP) plant. The fraction of adsorbed Au(CN) ₂ ⁻ that will be decomposed to AuCN was found to be a function of the pH and temperature of the solution and the type of activated carbon used. It was observed that two different batches of carbon from the same manufacturer yielded widely different ratios of AuCN to Au(CN) ₂ ⁻ , although their specifications did not differ much. These results were confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). A combination of low pH and high temperature, as is found in the hot acid wash step of an AARL elution, leads to the reduction of both Au⁽¹⁾ species to metallic gold, Au⁽⁰⁾. The fraction of the adsorbed Au(CN) ₂ ⁻ that is converted to AuCN or Au⁽⁰⁾ no longer participates in the equilibrium between Au(CN) ₂ ⁻ in solution and Au(CN) ₂ ⁻ in the adsorbed phase. It was observed that the isotherm for desorption is higher than the isotherm for adsorption by a percentage which is, on average, equal to the percentage of Au(CN) ₂ ⁻ converted to AuCN or Au⁽⁰⁾.     

溴化物溶液中活性炭吸附金的研究

用活性炭可从含金浸化物溶液中吸附金。在室温（２０－３５℃）；Ｃ：Ａｕ＝０．７ｇ：１ｍｇ；溶液ｐＨ＜６；溶液中化钠浓度小于０．２ｍｏｌ．Ｌ＾－＾１；适当搅拌下；吸附４ｈ，金金吸附率可达９５％以上。吸附反应为溶液，金扩散过程所控制。－ｄｃ／ｄｔ－ｋｃ；ｋ＝０．０３５３ｍｉｎ＾－＾１。吸附等温线可用朗格公尔缪式表示ｑ＝ｑ∞ａｃ／（１＋ａｃ），ｑ∞≈３３５ｍｇ．ｇ＾－＾１，ａ≈０．０５６２Ｌ．ｍｇ＾－＾１     

Effect of aromatic compounds on cellular fatty acid composition of Rhodococcus opacus

In cells of Rhodococcus opacus GM-14, GM-29, and 1CP, the contents of branched (10-methyl) fatty acids increased from 3% to 15 to 34% of the total fatty acids when the cells were grown on benzene, phenol, 4-chlorophenol, chlorobenzene, or toluene as the sole source of carbon and energy, in comparison with cells grown on fructose. In addition, the content of trans-hexadecenoic acid increased from 5% to 8 to 18% with phenol or chlorophenol as the carbon source. The 10-methyl branched fatty acid content of R. opacus GM-14 cells increased in a dose-related manner following exposure to phenol or toluene when toluene was not utilized as the growth substrate. The results suggest that 10-methyl branched fatty acids may participate in the adaptation of R. opacus to lipophilic aromatic compounds.