四种钆对比剂不良反应相关因素分析及处理方式

目的: 探讨四种钆对比剂临床应用中的不良反应（ADR）相关因素及最佳处理方式。方法: 通过比较对比剂特性、患者体质、诊疗类型、对比剂应用情况、增强前基础用药史及发生ADR情况（钆对比剂渗透压、注射后血液中存在形式、排泄途径；患者的年龄、性别、用药剂量、推注方式、增强时间、增强部位；ADR反应时间、严重程度、治疗后转归），综合分析对比剂不良反应发生相关因素，总结对比剂所致急性、晚发性及超晚发性ADR发生率、发生特点及相应临床处理方法。结果: 患者的年龄、注射流速、增强前基础用药、扫描部位是钆对比剂ADR的独立危险因素；线性离子型对比剂发生ADR最高；各系统症状及不同级别ADR严格对症处理；各个系统中均以急性皮肤症状最常见，无需特殊处理痊愈率较高，晚发性或超晚发性患者需给予抗组胺类或糖皮质激素药物治疗；我院随访4年内应用多次大剂量对比剂增强患者均未发现肾源性系统性纤维化（NSF）及齿状核、双肺、胸膜等部位钆沉积征象。结论: 环状对比剂相对发生ADR较少；患者增强前有基础用药史（糖尿病、变应性鼻炎、肿瘤病史）、增强时采取大剂量缓慢推注的体质量轻的中年门诊患者发生急性轻度ADR最高；影像科医务工作者应熟练掌握合理ADR的处理方法，合理使用对比剂能够有效的降低不良反应发生率。     

Chemical model for the solvent extraction of GdCl3 from a chloride solution with saponified PC88A

Solvent extraction experiments of Gd with 40% saponified PC88A have been conducted from a chloride solution under different extraction conditions. The effect of saponification of an acidic extractant on the extraction of Gd was investigated. To analyze the ionic equilibria of a GdCl₃ solution, we estimated the necessary thermodynamic properties from reported values. Moreover, when applying the chemical model developed in this study, we used experimental data to estimate the equilibrium constant for the extraction of Gd with partially saponified PC88A.     

Surface-engineered gadolinium oxide nanorods and nanocuboids for bioimaging

Folic acid and D-gluconic acid-capped gadolinium oxide nanorods and nanocuboids were synthesized via co-precipitation method.Comparative study of relaxivity factor on the role of capping and morphology for enhancing contrast ability for T_1 and T_2 magnetic resonance imaging(MRI) was investigated.The obtained r_2/r_1 ratio for folic acid and D-gluconic acid-capped gadolinium oxide nanorods and nanocuboids was 1.5 and 1.3,respectively.The nanocrystals were characterized and presented with properties such as good dispersity and stability required for standard contrast agent used in MRI.The characterization and the analysis of capping agent for nanocrystals suggest the preferable use of carbohydrate moieties with higher number of hydroxyl functional group reacted with urea and hydrogen peroxide for desired morphology and anisotropic growth.Thermogravimetric-differential thermal analysis(TG-DTA) illustrated the amount of capping,transition temperature from Gd(OH)_3 to GdOOH and crystallization temperature from GdOOH to Gd_2O_3.These nanocrystals would be significant for other biomedical applications such as drug delivery when equipped with well-functionalized drug molecules.     

Causes and control of welding cracks in electron-beam-welded superalloy GH4169 joints

Welding joint of GH4169 alloy with a good formation was obtained. No macroscopic defects occurred in the joint. The weld had mainly a dendritic structure; the base metal was a solid solution of Ni, Cr, and Fe, and the strengthening-phase particles such as Ni₃Nb were dispersively distributed along the grain boundary. The average tensile strength of the joint reached 743.7 MPa, and the Vickers hardness of the weld exceeded HV 300. Because of the segregation of the low-melting compound Ni₃Nb at the grain boundary of the fusion zone, liquid cracks tended to occur as a result of welding stress. The formation of liquid cracks was inhibited by adding an alloying element, Mn, to the welding bath, because Mn diffused to the fusion zone and the high-melting phase Mn₂Nb formed, and thus the overall properties of the joint were improved.     

还原剂与表面活性剂的覆盖效应在纳米片状银合成中的作用(英文)

研究还原剂与表面活性剂对于片状银形成的影响,考虑了两种弱还原剂:柠檬酸三钠、酒石酸钾,以及3种常用表面活性剂:聚乙烯吡咯烷酮、十二烷基磺酸钠、阿拉伯胶的影响。结果表明,以上弱还原剂与表面活性剂均具有可以与纳米银(111)面紧密结合的活性基团,从而产生覆盖效应阻止该晶面生长,最终达到形成片状银的目的。结果还显示,卤素离子的熟化作用在片状银生长过程中也存在一定的影响。     

Electrochemical impedance spectroscopy for the detection of stress corrosion cracks in aqueous corrosion systems at ambient and high temperature

Electrochemical impedance spectroscopy (EIS) has been used as a tool to detect stress corrosion cracking in a stainless steel sample exposed to an aqueous environment at ambient and high temperature. A model has been developed to describe the impedance of a cracked surface. This model could distinguish between a flat electrode surface and an electrode surface with cracks. To test this technique, three case studies were considered: (1) Slow Strain Rate Tests (SSRT) on sensitised Type 304 SS specimen in a 5 N H₂SO₄ + 0.1 M NaCl solution at room temperature, (2) constant load tests on Type 304 SS in a boiling (±110 °C) acidified sodium chloride solution, and (3) Slow Strain Rate Tests (SSRT) on Type 304 SS in an oxygen containing solution of 0.01 M Na₂SO₄ at 300 °C.EIS measurements were always performed simultaneously on two identical samples: one stressed with a SSRT or a constant load test and one free of stress. Kramers Kronig Transformations have been used to validate the experimental data obtained with the EIS measurements. It was shown that the phase shift between the two samples could be related to the stress corrosion cracking process. Analysis of the fracture surfaces confirmed that stress corrosion cracks were formed in all three cases.     

Untersuchung der Spannungsrißkorrosion eines niedriglegierten Röhrenstahls durch CO?CO2 in wäßriger Lösung

Investigation on stress corrosion cracking of low alloy pipeline steel by CO? CO₂ in aqueous solution Round bar tensile specimens of 5.2 mm gauge diameter taken from grade X 52 pipeline steel have been exposed to a 10^?3 molar NaCl solution purged with CO/CO₂ up to 5000 hrs at ambient temperature and pressure. The CO partial pressure was 0.1 and 0.3 bar; the remainder being from CO₂. All specimens had a weld in the gauge length. The applied load was 85% YS of the base material. Test parameters were: electropolished and anodically pre-corroded surface; 60%-V-notch in the weld. In the latter case the un-notched part of the gauge length was stressed to 60% YS only. External and internal cracks as well as different types of localised attack had been observed. Some of them can be described as typical for strain-induced corrosion cracks. In no case did the fracture occur in the notch region, which can be attributed to the increased YS of the weld metal. The lifetime markedly depends on CO pressure, and is about 5000 hrs for 0.1 bar. CO is a critical component for stress corrosion and pitting corrosion to occur. For high pressure service, condensation of water must be prevented or limited to a small period depending on the CO partial pressure.     

Pit to crack transition in stress corrosion cracking of a steam turbine disc steel

Long term exposure tests have been carried out on a 3 NiCrMoV steam turbine disc steel in the form of cylindrical tensile test specimens self-loaded to 90% of σ_0.2 and exposed to three environmental conditions, viz. deaerated pure water, aerated pure water, and aerated water containing 1.5 ppm of chloride ion. Pitting occurred in all environments but the density and depth of pits in the chloride-containing medium was markedly greater. No cracking was observed in deaerated pure water but cracks initiated in aerated water between 13 and 19 months and in less than 7 months in aerated 1.5 ppm Cl⁻ solution. The probability of a crack initiating from a pit of specific depth in aerated solution could be described well by a Weibull function. Profiling of pits and cracks in the disc steel tested in aerated 1.5 ppm Cl⁻ solution showed that there while there were many cracks with a depth greater than that of the corresponding pit the depth of some cracks was smaller than that of the corresponding pit, suggesting that cracks do not necessarily initiate from the bottom of the pits. The growth rate of short cracks emerging from pits appeared greater than that of long cracks in fracture mechanics specimens.     

Untersuchungen von Sonderfällen der Spannungskorrosion bei homogenen,nicht übersättigten Mischkristallen und der hierbei auftretenden elektrochemischen Prozesse. Teil II: Weitere Untersuchungen zur Spannungskorrosion des Messings

Research into special cases of stress corrosion with homogeneous, non-over-saturated mixed crystals, and of the electro-chemical processes associated with it. Part II. Further research into the stress corrosion of brass Stress corrosion in brass is caused not only by basic agents which though free from ammonia, contain Cu⁺⁺ ions; the effect of these agents, however, is less marked. These agents contain, as a reaction product, Cu₂O which forms the cathodic zone required for the setting up of a marked electro-chemical process in the fissures and cracks and which, in contrast to CuO, is resistant even in acid solutions up to a p_H value of approx. 2. With Ms 70 and 63, the crack pattern is mainly transcrystalline, with peculiarly ramified and extended cracks. This is explained by the fact that Cu₂O occurs in isolated un-linked crystals and therefore does not form a uniform cover of the walls of the cracks. The walls are therefore exposed to intensified local corrosion which leads to ramifications of the cracks.     

Physicochemical properties of solutions and ultrathin films of triple-decker gadolinium tetra-15-crown-5-phthalocyaninate

The ability of the triple-decker gadolinium complex with tetra-15-crown-5-phthalocyanine Gd₂(R₄Pc)₃, (R = 15-crown-5) (1) to form monolayers and Langmuir-Blodgett films (LBFs) was studied for the first time. The charge characteristics of molecules of a triple-decker phthalocyaninate in monolayer, as well as their orientation and adhesion to the water subphase, were controlled by changing the surface pressure, pH, and subphase composition (aqueous solutions containing triethylenetetramine (TETA) and metal cations). It was shown that the presence of Na⁺ and protonated TETA aminogroups in resulted in an increasing limiting monolayer area and significant decreasing of the monolayer liquid state region. It is proven that the observed effects are caused by the conformational and charge transitions of peripheral crown ethers induced by their interaction with cations. A comparison of the differential reflectance spectra of the complex monolayer on the deionized water surface with UV-Vis absorption spectra of three-layer Gd₂(R₄Pc)₃ LBF and complex solution in chloroform shows that partial complex oxidation and intensive stacking formation occurs already at the stage of monolayer formation on the subphase surface. Electrochemical studies of three-layer LBFs performed at the indium-tin-oxide electrodes (ITO-electrodes) using cyclic voltammetry (CV) showed three reversible redox waves in the potential range −200 to +1100 mV (vs. Ag⁺/AgCl). All registered peaks remain the same position and intensity upon multiple cycling. plasmon resonance (SPR) measurements allow to register three stable redox states of studied LBF upon applying the external potential. Such behavior shows the possibility to use multistep redox transformations of studied complex LBF for developing of stable and reproducible switchable optoelectronic systems.     

Synthesis of CeO2/TiO2 nanoparticles by laser ablation of Ti target in cerium (III) nitrate hexahydrate (Ce(NO3)3·6H2O) aqueous solution

A new synthesis process, laser ablation in an aqueous solution of target material, was applied to synthesize nanostructured CeO₂/TiO₂ catalyst particles. Reactivity within the laser plume (plasma) can be used to synthesize CeO₂ from an aqueous solution, 2 M cerium (III) nitrate hexahydrate (Ce(NO₃)₃·6H₂O) aqueous solution, and to fabricate TiO₂ from Ti target. CeO₂/TiO₂ nanoparticles were successfully synthesized by the laser ablation of Ti target in 2 M cerium (III) nitrate hexahydrate (Ce(NO₃)₃·6H₂O) aqueous solution. Laser ablation of Ti in a liquid environment and chemical reactions of the solution within a plasma plume are discussed.     

Performance and comparison of gold-based neutron flux monitors

In two test series, liquid and solid gold-based neutron flux monitor materials were investigated with respect to the effects of neutron absorbers such as chlorine, scattering effects, and the dependence of the enhanced activation caused by the epithermal resonance integral. The liquid monitors were prepared from aqueous solutions of tetraamminegold(III) nitrate and tetrachloroauric(III) acid. The presence of chlorine-35 partly suppresses the activation of gold-197; this effect depends not only on the concentration of the absorber but also on the state of the neutron flux density monitor. Aqueous samples show greater relative losses than solid monitors. Neutron scattering occurs in hydrogen-rich sample matrices which is shown by the fact that cadmium-shielded aqueous samples show an over proportional activation. Hence, fast neutrons must be moderated to the epithermal energies covered by the resonance integral, which is characterized by much greater cross sections for the capture of neutrons. The insight of this study with respect to neutron scattering in hydrogen-rich matrices must be taken into account also for neutron activation analysis; sample and standard must have a similar matrix with respect to its neutron scattering properties, otherwise the effect of increased activation as well as of enhanced self-shielding are underestimated.     

3A21型铝合金高效复合型表面处理液的工艺研究

目的研制一种高效、复合水基型铝合金表面处理液。方法以几种表面活性剂、混合酸为主要原料,以铝合金表面的油污去除率和Al2O3膜的去除能力作为性能评价的定量因子。通过正交试验确定了表面处理液的组分,同时对表面处理液的综合性能进行测试。结果表面处理剂的最佳配方为脂肪醇聚氧乙烯醚4.8 g/L(AEO-7 4.0 g/L,AEO-9 0.8 g/L)、烷基醇聚氧乙烯醚(OP-10)1.0 g/L、十二烷基苯磺酸钠(SDBS)0.6 g/L、硫酸(H2SO4)4.0 g/L、磷酸(H3PO4)6.0 g/L,采用浸泡处理20~30 min。实验结果表明该表面处理液具有较强的稳定性,同时具有优良的去油污和去Al2O3膜的能力。结论该型表面处理剂的组分廉价易得,且工业处理过程中对设备没有其他特殊的要求,因此该型表面处理液可以广泛的用于3A21型铝合金材料的预处理,在工业上具有较大的运用潜力。     

Corrosion and electrochemical behaviors of pure aluminum in novel KOH‐ionic liquid‐water solutions

The corrosion and electrochemical behaviors of pure aluminum in KOH‐ionic liquid‐water solutions with variable volume ratios of water and the ionic liquid 1‐butyl‐3‐methyl imidazolium tetrafluoroborate (BMIMBF₄) were for the first time investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, and electrochemical impedance spectroscopy (EIS). The results of hydrogen collection experiments showed that aluminum has a low corrosion rate in KOH‐BMIMBF₄‐H₂O solutions, and the corrosion rate decreases with increase in BMIMBF₄ content in the electrolytes. The results of electrochemical experiments revealed that aluminum is electrochemically active over a very wide potential window in the KOH‐BMIMBF₄‐H₂O solutions, and its electrochemically kinetic mechanism is similar to that in the corresponding aqueous solution; the increase in KOH and water contents in the electrolytes may improve the anodic dissolution performance of aluminum. It was found that aluminum presents excellent galvanostatic discharge performance in the 2.0 M KOH BMIMBF₄‐H₂O mixed solution with 60% water.     

Investigation of the SCC behaviour of alloy 2024 using the slow strain rate technique

The stress corrosion cracking (SCC) behaviour of 2024 plate in T351 and T851 tempers was investigated in short transverse direction performing accelerated tests under constant deformation, constant load and slow strain rate conditions. Corrosive media used were: aqueous 3.5% NaCl solution, an aqueous solution of 2% NaCl + 0.5% Na₂CrO₄ at pH 3 (according to LN 65666), an aqueous solution of 3% NaCl + 0.3% H₂O₂, and substitute ocean water according to ASTM D1141. Alternate immersion tests in 3.5% NaCl solution indicated the low SCC resistance of the alloy 2024-T351 as well as the improved SCC behaviour due to aging to T851 condition. Similar results were obtained from constant load tests under permanent immersion conditions in the acidified chloride-chromate solution, in 3% NaCl solution with peroxide, and in substitute ocean water, whereas no SCC failure was observed with specimens which were permanently immersed in 3.5% NaCl solution. Using the slow strain rate method, 3% NaCl + 0.3% H₂O₂ and substitute ocean water were found to be effective synthetic environments. The other two electrolytes did not promote severe stress corrosion cracking with alloy 2024-T351. The SCC behaviour of 2024-T851 was difficult to determine employing the slow strain rate technique. Large scatter in data, observed even in inert environment, and the low elongation of the aged material, exacerbated by a further degradation of ductility due to pitting and intergranular corrosion, precluded an evaluation.     

An investigation on the effect of bleaching environment on pitting corrosion and transpassive dissolution of 316 stainless steel

Pitting corrosion and transpassive dissolution of 316 stainless steel in a solution containing five percent of commercial bleaching liquid was investigated by employing potentiodynamic polarization method and recording corrosion potential during immersion. Today commercial bleaching liquids are widely used as a cleaner additive. Therefore those house appliances made from stainless steels are in contact with aqueous solution containing bleaching liquid. This may cause severe localized corrosion and transpassive dissolution. In order to investigate the possibility of tranpassive dissolution of stainless steel by bleaching liquid, potentiodynamic polarization and recording the variation of corrosion potential of specimens were carried out in 0.2 M Na₂SO₄ solution containing 5%wt. commercial bleaching liquid. A 500 mV drop in transpassive potential and also instantaneously ennobled corrosion potential revealed the possibility of transpassive dissolution due to the oxidizing effect of the species such as free chlorine and its derivatives in bleaching liquid. Evaluation of the occurrence of localized corrosion at the presence of Cl^? and bleaching liquid was investigated by similar electrochemical experiments in 0.2 M Na₂SO₄ + 0.4 M NaCl containing 5%wt. bleaching solution. Initiation of stable pitting at potentials lower than the transpassive potential as well as a sharp increase of the corrosion potential in this environment demonstrates the possibility of pitting corrosion.     

Microstructure and Thermophysical Properties of SrZrO<Subscript>3</Subscript> Thermal Barrier Coating Prepared by Solution Precursor Plasma Spray

Strontium zirconate (SrZrO₃) thermal barrier coatings were deposited by solution precursor plasma spray (SPPS) using an aqueous precursor solution. The phase transition of the SrZrO₃ coating and the influence of the aging time at 1400 °C on the microstructure, phase stability, thermal expansion coefficient, and thermal conductivity of the coating were investigated. The unique features of SPPS coatings, such as interpass boundary (IPB) structures, nano- and micrometer porosity, and through-thickness vertical cracks, were clearly observed evidently in the coatings. The vertical cracks of the coatings remained substantially unchanged while the IPB structures gradually diminished with prolonged heat treatment time. t-ZrO₂ developed in the coatings transformed completely to m-ZrO₂ phase after heat treatment for 100 h. Meanwhile, the SrZrO₃ phase in the coatings exhibited good phase stability upon heat treatment. Three phase transitions in the SrZrO₃ coatings were revealed by thermal expansion measurements. The thermal conductivity of the as-sprayed SrZrO₃ coating was ~1.25 W m^?1 K^?1 at 1000 °C and remained stable after heat treatment at 1400 °C for 360 h, revealing good sintering resistance.     

Nanoscale synthesis and optical features of metallic nickel nanoparticles by wet chemical approaches

Nickel nanoparticles (Ni-NPs) were successfully synthesized and attached on indium tin oxide (ITO) substrate by two different methods: from solution reduction process by using sodium borohydride (NaBH₄) as reducing agent in the presence of poly(N-vinilpyrrolidone) (PVP) as protective and stabilizing agents and by polyol process under ethylene glycol EG as a solvent. The results indicated that the samples prepared in aqueous solution show the occurrence of face-centered cubic metallic nickel nanoparticles with a medium diameter of ∼31 nm and good size dispersion compared to the preparation in EG that revealed large size ∼150 nm. The dynamics of the nanoparticle's growth in the solvents and comparison with optical absorption is presented.     

纳米 SiO2的改性及其对水性聚氨酯树脂复合涂层性能的影响

在乙醇水溶液中,用硅烷偶联剂KH560对纳米SiO2进行表面改性处理,通过测定粒径,探讨了纳米SiO2含量、乙醇水溶液配比以及改性剂含量对分散性的影响。将改性后的纳米SiO2分散液、水性聚氨酯树脂及无机组分等复配成无铬钝化液,在热镀锌板上制备钝化膜,通过电化学Tafel极化曲线、交流阻抗以及中性盐雾试验对比纳米SiO2改性聚氨酯复合钝化膜和未改性聚氨酯复合钝化膜的耐蚀性,结果表明,与后者相比,前者的耐腐蚀性能有了较大的提升。     

Corrosion of austenitic stainless steels in hot concentrated aqueous NaOH solutions

When austenitic stainless steel is exposed to a hot concentrated aqueous NaOH solution, two corrosion products are formed at the surface: (i) nickel, building up as a superficial metallic layer, and (ii) mixed oxide of the type NaMO₂, finely dispersed in the underlying austenite. The electrochemical and crystallographic factors which govern the growth of these products have been studied. The thermodynamics and kinetics of their formation are discussed. The morphology of the mixed oxide small crystals and their orientation relationships with the metallic matrix are such that they may be liable to initiate cracks. This possibility of crack initiation by the corrosion products is presented as a working hypothesis for the extension of this study.