^125I,^131I诱发小鼠精子畸形发生率比较

本文选用 ICR 雄性小鼠,经腹腔分别注射不同剂量的~(125)I 及~(131)I,观察并比较它们对小鼠精子畸形发生率的影响及染毒后睾丸中放射性活度的变化。实验结果表明:(1)~(125)I 染毒后4—5周,0、185、370和555 kBq 各组精子畸形发生率分别为9.00‰、9.57‰、11.6‰及13.9‰;~(131)I 染毒后4—5周,上述各组精子畸形发生率分别为8.50‰、12.5‰、14.7‰和15.5‰;在相同注入量下,~(125)I 与~(131)I 诱发小鼠精子畸形发生率的差异各组均不显著(X~2检验,p>0.05)。(2)~(125)I、~(131)I 染毒后2h 至7天内,两者在睾丸中的放射性活度及变化规律相似,即在染毒后2h 达最高值,每克睾丸中~(125)I 和~(131)I 的放射性活度分别占初始注入量(370 kBq)的0.72％和0.50％,然后迅速下降,至一周时,仅分别占初始注入量的0.035％和0.011％。     

Characterization of products from fast and isothermal hydrothermal liquefaction of microalgae

We investigated nonisothermal (fast) and nominally isothermal hydrothermal liquefaction (HTL) of Nannochloropsis sp. microalgae for the production of biocrude. Biocrude yields ranged from 36 to 45 wt % (dry weight), with fast HTL with low mass loading giving the highest yield. This condition also gave the biocrude with the lowest heating value, which indicates there are compromises to be made between biocrude quantity and quality. The aqueous phase and biocrude product fractions were characterized using elemental analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS). This detailed level of analysis identified more than 30,000 unique molecular products. The aqueous phase products included compounds with the same molecular formulae as known herbicides, which may inform efforts in genetic engineering of algae and/or bacteria for cultivation on the aqueous phase. This detailed molecular‐level characterization provides some clues regarding the types of reactions that may take place during HTL. © 2016 American Institute of Chemical Engineers AIChE J, 62: 815–828, 2016     

神华煤钌离子催化氧化解聚产物的FT-ICR MS分析研究

针对神华长焰煤初步开展了钌离子催化氧化法(RICO)的应用研究,对原煤进行降解反应并尝试运用高分辨电喷雾傅里叶质谱仪（ESI-FTMS）对氧化产物进行分析表征。结果表明,神华煤含有C-2～C-32烷基侧链和连接芳环之间的C-2～C-27亚甲基桥链,芳环缩合程度相对较低（主要以含有2～4个苯环的共轭结构为主）,有较多醚键连接的芳环结构及羟基（-OH）、羰基（CO）和甲氧基（-OCH-3）等含氧官能团存在。     

Dynamic Low-Frequency Electrical Impedance of Biological Materials Subject to Freezing and Its Implementation in Cryosurgical Monitoring

A precise monitoring of the extent of freezing during a cryosurgical process has been an important problem in health-care clinics. Among various existing techniques, the dynamic electrical impedance utilizing the impedance jump to detect the ice moving front, is a suitable way because the impedance of frozen tissue is much higher (3 to 4 orders of magnitude or even larger) than that of unfrozen tissue. Based on two experimental setups, the dynamic low-frequency impedance (DLFI) and impedance changing rate (ICR) for selected biological materials (fresh pork and rabbit tissues) subject to freezing were systematically measured. Their transient behaviors were investigated, and implementations in a practical cryosurgery to detect ice front propagation were analyzed. Furthermore, in vitro experiments were performed on distilled water and phantom gel. The experimental results, obtained with a two-electrode measuring technique, are as follows: (1) The impedance of all samples has a rapid response to the external freezing. (2) The impedance will not jump into an insulation region when the cooling temperature is not low enough. (3) As an alternative to DLFI, ICR imaging can also give important information for the phase-change process, which may lead to an efficient method to detect the ice-ball growth. (4) There is an evident variation in DLFI for different biological tissues when subjected to the same cooling temperatures; this value also differs for the same tissue under different cooling conditions.     

一种辅助改善记忆保健食品功能评价的动物模型

目的 为辅助改善记忆类保健食品的功能评价提供新的动物模型.方法使用滚筒睡眠干扰仪对小鼠进行不同时间(5、10、15 d)睡眠干扰后,用自主活动仪检测自主活动,水迷宫、避暗试验检测认知功能.结果 干扰5d组小鼠的自主活动、水迷宫定位航行和空间探索、避暗训练和检测各指标与对照组比较,差异无统计学意义;干扰10 d组与对照组比较,自主活动总路程、平均速度、运动总时间增加,水迷宫定位航行潜伏期从第4d起增加,空间探索穿台次数的差异无统计学意义,避暗训练错误次数、潜伏期、暗室路程增加,避暗检测的差异无统计学意义:干扰15d组与对照组比较,自主活动差异无统计学意义,水迷宫定位航行潜伏期增加、空间探索穿台次数减少,避暗训练错误次数、潜伏期、暗室时间、暗室路程增加,明室时间显著减少,避暗检测差异无统计学意义.结论 采用本法,干扰5d对小鼠自主活动和认知功能无影响,干扰10 d影响小鼠自主活动、损害其空间学习和避暗学习能力,干扰15d不影响小鼠自主活动、损害其空间学习记忆和避暗学习能力,可为辅助改善记忆类保健食品的功能评价提供新的动物模型.     

Fourier transform ion cyclotron resonance mass spectrometry at the true cyclotron frequency

Ion cyclotron resonance (ICR) cells provide stability and coherence of ion oscillations in crossed electric and magnetic fields over extended periods of time. Using the Fourier transform enables precise measurements of ion oscillation frequencies. These precisely measured frequencies are converted into highly accurate mass-to-charge ratios of the analyte ions by calibration procedures. In terms of resolution and mass accuracy, Fourier transform ICR mass spectrometry (FT-ICR MS) offers the highest performance of any MS technology. This is reflected in its wide range of applications. However, in the most challenging MS application, for example, imaging, enhancements in the mass accuracy of fluctuating ion fluxes are required to continue advancing the field. One approach is to shift the ion signal power into the peak corresponding to the true cyclotron frequency instead of the reduced cyclotron frequency peak. The benefits of measuring the true cyclotron frequency include increased tolerance to electric fields within the ICR cell, which enhances frequency measurement precision. As a result, many attempts to implement this mode of FT-ICR MS operation have occurred. Examples of true cyclotron frequency measurements include detection of magnetron inter-harmonics of the reduced cyclotron frequency (i.e., the sidebands), trapping field-free (i.e., screened) ICR cells, and hyperbolic ICR cells with quadrupolar ion detection. More recently, ICR cells with spatially distributed ion clouds have demonstrated attractive performance characteristics for true cyclotron frequency ion detection. Here, we review the corresponding developments in FT-ICR MS over the past 40 years.     

Formable chromium nitride coatings for proton exchange membrane fuel cell stainless steel bipolar plates

Among the different coatings developed for proton exchange membrane fuel cell steel bipolar plate, nitride-based coatings present several advantages compared to gold or polymeric coating: high chemical stability, low interfacial contact resistance and reasonable cost. In this work, 50 nm thick chromium nitride coatings are deposited by reactive magnetron sputtering on 316L stainless steel foil. They are optimized to fulfill the Department of Energy targets in terms of interfacial contact resistance (ICR) and corrosion resistance, with values of 8.4 mΩ cm⁻² (at 100 N cm⁻²) and 0.10 μA cm⁻² (in 0.6 M H₂SO₄ solution at 0.48 V_vs. SCE potential) respectively. Moreover, they retain their excellent properties after high deformation (biaxial deformation of 20% in x-axis and 5% in y-axis), giving the possibility to achieve, in line, the stamping of a bipolar plate from a coated foil. The etching of the substrate, prior to the coating deposition, appears to be determinant to obtain low and stable corrosion current and ICR. The removing of interfacial oxyde leads to better coating adhesion and improves the corrosion resistance and electrical conductivity. The enhancement of the properties (low ICR and high corrosion resistance) is durable, with no signicant change of the ICR value up to 200 days after deposition.     

On the dependence of interfacial resistance on contact materials between cathode and interconnect in solid oxide fuel cells

The dependence of interfacial contact resistance (ICR) on contact materials between cathode and interconnect is systematically studied under both isothermal oxidation and thermal cycling conditions. Three kinds of cathode current-collecting layer (CCCL) are used, (La,Sr) (Co,Fe)O₃ (LSCF), LSCF+10%Ag, and Ag, and tested in a SUS430/CCCL/SUS430 sandwich structure to simulate the actual operation of the solid oxide fuel cells (SOFCs). Experimental results show that the ICR of LSCF+10%Ag exhibits the smallest value, in comparison with the specimens with LSCF and Ag paste, as well as the sample without a CCCL. For LSCF+10%Ag contact, the ICR increases from 0.0069 mΩ cm² to 3.74 mΩ cm² under an isothermal condition for 150 h, then increases from 3.74 mΩ cm² to 10.79 mΩ cm² after 15 thermal cycles. This work provides information for the understanding of possible mechanisms of performance degradation of SOFCs.     

Assessment of immobilized cell reactor and microbial fuel cell for simultaneous cheese whey treatment and lactic acid/electricity production

Two biological methods for treatment of cheese whey and concentrated cheese whey were investigated in this research. As the first method, fermentation of cheese whey for production of lactic acid, in an immobilized cell reactor (ICR) was successfully carried out. The immobilisation of Lactobacillus bulgaricus was performed by the enriched cells cultured media harvested at exponential growth phase. Furthermore, the FTIR analysis has been done to prove the production of lactic acid. The COD removal during the continuous process for both whey and concentrated whey was above 70% which showed the capability of reaction for wastewater treatment. The cells were immobilised by sodium alginate as a perfect polymer in this regard. The maximum produced lactic acid from whey was 10.7 g l^?1 at 0.125 h^?1 and 19.5 g l^?1 from concentrated whey at 0.063 h^?1. Finally it can be concluded that the process is efficient for lactic acid production and COD removal simultaneously. As the second studied method, whey and concentrated cheese whey were used as the sources of carbon in a microbial fuel cell. The power densities of 188.8 and 288.12 mW m^?2 were recorded for whey-fed and concentrated whey-fed MFCs while the COD removal were 95% and 86% respectively. Biological wastewater treatment can be a very efficient alternative for traditional wastewater treatment which selecting any and or integrating of them depends on specific applications needed to be achieved.