HPLC study of tissue distribution of loganin in rats

A rapid, sensitive and selective high performance liquid chromatography (HPLC) method was developed and validated for determination of loganin in rat tissues. Samples were prepared based on a simple protein precipitation. Separation of loganin was achieved on a reversed-phase C(18) column (250 x 4.6 mm, 5 microm) with a mobile phase consisting of acetonitrile and water (16:84, v/v) at a flow rate of 1.0 mL/min. The detection wavelength was set at 236 nm and the temperature of the column was kept at 30 degrees C. The method was applied to study tissue distribution of loganin in rats after a single administration of loganin at a dose of 20 mg/kg. The highest level was observed in kidney, then in stomach, lung and small intestine. The lowest level was found in brain. The peak levels were attained at 90 min in most tissues. It was indicated that kidney was the major distribution tissue of loganin in rats, and that loganin had difficulty in crossing the blood-brain barrier. It was also found there was no long-term accumulation of loganin in rat tissues.     

悬浮液气-液界面二元胶体颗粒的漂浮组装机理

提出一种在悬浮液气-液界面漂浮组装亚微米单分散聚苯乙烯(PS)微球和纳米SiO2颗粒二元胶粒晶体的新方法, 并系统研究了漂浮组装机理. 研究表明, 聚苯乙烯微球和二氧化硅两种胶体颗粒在悬浮液气-液界面的漂浮组装是以PS微球的组装为主导的. 在一定PS微球相浓度范围内, 悬浮液中PS 微球与SiO2颗粒的初始体积配比基本不影响PS微球有序组装的形成. PS微球粒径在150-500 nm时易于形成有序排列, 较小或较大粒径的PS微球难以形成有序排列. SiO2颗粒的组装是一种以PS微球为“基底”的沉积过程. 二元胶粒晶体中SiO2颗粒的体积分数由其在混合悬浮液中的相浓度所决定.     

Cardiovascular effects of mycelium extract of Ganoderma lucidum: inhibition of sympathetic outflow as a mechanism of its hypotensive action

In an effort to understand the mechanism of cardiovascular actions of Ganoderma lucidum which was cultivated in Korea, the mycelium was isolated for a large-scale culture. Water extract of the mycelia was evaluated for its cardiovascular activity in anesthetized rabbits and rats. The left femoral artery and vein were cannulated for the measurement of arterial pressure and subsequent delivery of drugs. The left kidney was exposed retroperitoneally and a branch of the renal nerve was used to integrate renal efferent or afferent nerve activities. The extract decreased systolic and diastolic blood pressure, which was accompanied by an inhibition of renal efferent sympathetic nerve activity. The extract did not decrease heart rate in these animals, although there was clear hypotension in the extract dose dependent manner. This suggests that the hypotension induced by the treatment of the extract was secondary to the primary effect of the extract in the central nerve system, which suppressed the sympathetic outflow. Therefore we concluded that the mechanism of hypotensive action of Ganoderma lucidum was due to its central inhibition of sympathetic nerve activity.     

Determination of nitrite by inhibition of the chemiluminescence of acriflavine in a flow-injection assembly

The indirect determination of nitrite was performed with a flow-injection assembly on the basis of the inhibition of the analytical output obtained in a luminometer by oxidation of acriflavine. The acriflavine solution merged with the nitrite and the resulting mixture was injected into a pure water stream. This solution merged with the oxidant solution (potassium permanganate in sulfuric acid medium) and the resulting chemiluminiscence was affected (inhibited) by the presence of nitrite after reaction with the aminoacridine. The method was applicable over the range 10-800 microg l(-1) of nitrite with a correlation coefficient of 0.9960. The relative standard deviation was 1.4% and the throughput was 76 samples h(-1). The influence of foreign substances was also tested. A solid-phase reactor, filled with Amberlite IRA-900, was inserted in the assembly for the on-line preconcentration of nitrite; the analytical output resulted in an increase of up to 11.5-fold. The method was applied to the determination of nitrites in residual waters, industrial formulations and soil samples.     

离子色谱仪检定及整机性能不确定度评定

介绍电导检测器离子色谱检定方法。采用氯离子标准物质,使用泵流量设定值误差、流量稳定性、基线噪声、基线漂移、最小检测浓度、线性相关性、整机性能定性定量重复性等参数对离子色谱仪进行检定。同时用5 μg/mL氯离子为检测离子,结合JJF 1059.1–2012 《测量不确定度评定与表示》对整机性能不确定度来源进行考察。结果表明:在置信区间为95%时(包含因子k=2),氯离子的质量浓度为(4.94±0.35)μg/mL。经不确定度分析,标准工作曲线拟合引入的不确定度最大,其次是样品的重复随机测试过程。     

导数测量技术在气相色谱信号处理中的应用

介绍了导数测量技术在气相色谱信号处理中的应用。导数-气相色谱的热导检测器对苯的灵敏度和敏感度分别达到270kV·L/kg和0.3μg／L。与可分辨导数色谱峰相对应的常规色谱峰最小分离度为2．8。在被测组分质量浓度为8．1～810g／L的范围内,导数峰上峰高、下峰高、总峰高、峰面积均与质量浓度呈线性关系,其线性相关系数分别为0．9911,0．9982,0．9960和0.9991。     

Distribution of 67Ga-citrate in 3'-methyl-4-dimethylaminoazobenzene-induced hepatoma of rats

The distribution of 67Ga-citrate in the hepatoma of rat induced by 3'-methyl-4-dimethylaminoazobenzene was studied. 67Ga uptake ratio resected specimen, autoradiography and histological specimen were compared each other. 67Ga uptake ratio of the tumor was increased 1.6 to 7.2 times (average 4.4) to control group. Regardless of the size of the tumor, macroautoradiographically observed distribution of 67Ga-citrate in the hepatoma was higher in the peripheral zone than in the central zone. Histologically the degeneration of tumor cell was low or absent in the peripheral zone of tumor, whereas it was intense in the central zone. 67Ga-citrate was highly accumulated in the zone which the degeneration was low or absent. We, however, could not demonstrate the site where 67Ga-citrate was incorporated.     

LC Evaluation of Intestinal Transport of Praziquantel

Praziquantel (PZQ) is a highly lipophilic drug with low aqueous solubility. Despite this, it is well absorbed from the gastrointestinal tract. In this study, a simple LC method was developed and validated, in order to monitor the concentration of PZQ in TC-199 buffer in vitro, in the rat everted gut sac absorption model. PZQ was analyzed by a reversed-phase LC method with an isocratic mobile phase containing acetonitrile and water in the proportions 45:55. The flow-rate was 1 mL min⁻¹ and PZQ was determined by measuring absorbance at 215 nm, at 25 °C. The method was found to be specific, as none of the components of TC-199 or intestinal sac artefacts interfered with the drug peak. Recovery was within acceptable statistical limits. The limit of detection was 0.54 μg mL⁻¹ and the limit of quantitation was 1.63 μg mL⁻¹. The calibration curve was found to be linear in the concentration range of 10–90 μg mL⁻¹ PZQ. The proposed method was found to be rapid and selective and hence can be applied in the monitoring of the absorption of PZQ in in vitro everted gut sac absorption studies.

     

思密达治疗口腔溃疡的临床观察

1998年8月－1999年3月采用思密达治疗口腔溃疡32例，并与红霉素（含强的松，维生素B2）治疗口腔溃疡30例比较，结果表明，治疗4天后，思密达组显效率75．00％，总有效率100．0％，而红霉素组显效率6．67％，总有效率40．0％，提示思密达治疗口腔溃疡有较好的临床效果。     

电感耦合等离子体原子发射光谱法测定钒铁中8个杂质元素含量和方法精密度的验证

提出了电感耦合等离子体原子发射光谱法(ICP-AES)测定钒铁中硅、磷、铝、锰、镍、铬、铜、钛共8个杂质元素含量的方法。钒铁样品(0.5000g),先后加入50%(体积分数)硝酸溶液20mL及50%(体积分数)盐酸溶液10mL,在100℃左右加热溶解,溶解过程中应注意保持溶液体积在25mL左右。将溶液过滤并置于200mL容量瓶中作为母液留用。将滤纸及不溶物一并移入铂坩埚中,置于马弗炉中,先于250℃灰化20min,稍冷后加入无水碳酸钠和硼酸(质量比2∶1)组成的混合熔剂0.3g,升温至950℃融熔15min。冷却,用体积比1∶10的盐酸溶液10mL浸出熔块,将此溶液与上述母液合并并加水定容至200mL。此溶液供ICP-AES在仪器工作条件下进行分析。绘制校准曲线时,加入纯铁和五氧化二钒作为基体,以消除基体干扰,然后加入上述8种元素的标准溶液,并按上述溶液最终稀释体积条件和仪器工作条件制作曲线(R大于0.999)。为验证所提出的分析方法的测定数据的精密度,约请了10个实验室对8个不同含量水平的钒铁样品对方法作协同试验,按GB/T 6379.2-2004所规定的方法求算了重复性标准偏差Sr和重复性限r,以及再现性标准偏差SR和再现性限R,并求得所测定的8种元素在各自的测定范围内的r与w之间和R与w之间的函数关系,说明该方法有较好的稳定性和准确性,而且证明此方法是可行的。     

转动弹量热计的建立及对氯苯甲酸热值测定

元素有机物要达到完全的燃烧应当在转动弹量热计中进行,这种量热计与静止弹量热计比较有许多优点。首先,转动的结果起到了对弹液的搅拌作用,使弹内各部分溶液的浓度很快达到平衡。其次,促进了燃烧过程中某些副反应的进行,从而短期获得稳定的反应终态,使燃烧热测量的精度显著提高。     

全自动凯氏定氮仪测定化肥中的含氮量

建立全自动凯氏定氮仪检测化肥中氮含量的分析方法。称取总氮量在0.03~0.3 g范围的样品,经消解仪消解及全自动凯氏定氮仪碱化蒸馏,以硼酸为接收液,用0.15~0.20 mol/L的盐酸标准溶液进行自动滴定。该方法加标回收率为99.0%~101.5%,测定结果的相对标准偏差小于1.0%(n=6)。与国标GB/T 8527–2010法测定结果无显著性差异,全自动凯式定氮仪法的准确度、精密度均优于国标方法,而且所用试剂少、分析时间短,满足实验室快速检测大批量化肥中含氮量的需要。     

Neutron activation analysis of the distribution of inorganic elements among five varieties of Brazilian corn

Instrumental neutron activation analysis (INAA) was applied to determine the elements Br, Ca, Cl, Cu, Fe, I, K, Mg, Mn, Na, Rb, S, V, Zn in five varieties of Brazilian corn, resulting from the studies carried out in order to increase their protein contents. The accuracy of the method was evaluated by means of reference material analysis. In general, the precision of the method was lower than 15%, except for Cu, I and S. Sensitivity and detection limit were also determined. Besides, tryptophan contents were determined. It was observed that the tryptophan content in improved corn samples was twice as large as in the normal samples. However, the same ratio was not observed in the inorganic element contents.     

统计方法在微量金分析中的应用

化探金样品前处理过程中消解、富集、解吸等环节控制不严格,往往会导致最后数据处理产生过高的校正系数。为了降低校正系数,用统计学的方法对实验过程进行了详细分析,确定了主要影响因素。将水浴时间延长并保温3 h以上,泡塑大小改为0.2 g,清洗时间不大于15 s,解吸到上机时间间隔小于5 h。方法改进后,检测结果校正系数有了明显改善,从改进前有40%批次的校正系数大于1.2,降到了全部小于1.2,甚至不用校正。方法改进后降低了实验过程的误差,提高了分析测试结果的稳定性。     

理解“角落”的影响：流体在矩形纳米孔中的吸附

本文通过巨正则系综Monte Carlo方法研究了不同孔径下氮气、氢气和甲烷在方孔和矩形孔中的吸附。比较了三种势能模型后,采用了最合理的点对点模型。比较了77K时流体在圆柱状孔、方孔和矩形孔的吸附。由于“角”的影响,在方孔和矩形孔内有明显的润湿效应,而圆柱状孔内则没有。文章中比较了氢气和甲烷在三种不同的孔内吸附的情况。研究表明：氢气在方孔内的吸附能力最强,在低压时尤为显著,这是因为“角落”处势能重叠的作用。结果显示在低压时,“角”的存在对流体的吸附和相行为有较强的影响。     

比对法在计量标准考核验证中的应用探讨

为探讨比对法在计量标准考核验证中的可行性,将5家实验室分别对同一分度吸量管的检定结果进行比对,同时采用具有溯源性的传递比较法进一步验证比对法的可靠性。验证结果显示,采用比对法和传递比较法对被考核实验室的验证结果一致,说明采用比对法对检定结果的验证是有效的、可行的。     

纳米催化剂在CO_(2)加氢制甲醇中的研究进展北大核心CSCD

为减缓温室效应,将CO_(2)转换成高附加值的甲醇是减少CO_(2)排放的有效途径,而高效催化剂是CO_(2)加氢制甲醇反应规模化的关键.可调控合成的具有量子尺寸效应的纳米催化剂在该反应上具有独特的优势.因此我们深入探讨了反应机理,综述了纳米材料在CO_(2)加氢制甲醇中的研究进展,最后给出了高效催化剂可能的发展方向.     

Enhancement of the enzymatic digestibility of waste newspaper using tween

Methods of increasing the enzymatic digestibility of waste newspaper by adding Tween (TW)-20 and 80 surfactants were investigated. Tween-series surfactants were selected because these surfactants increase cellulase activity during enzymatic hydrolysis and do not inhibit cell growth in downstream fermentation processes. When surfactant was used in a pretreatment, a benefic effect was expected in the enzymatic hydrolysis stage owing to surfactant carry-over from the pretreatment stage immediately upstream of the hydrolysis. However, because it was necessary to wash the pretreated substrate with water to remove inhibitors produced during pretreatment, no added benefit was obtained. When surfactant was used in the pretreatment only, it was found that it had a marked effect on digestibility and that this effect was higher at lower enzyme loadings. Also, TW-80 was found to be more effective than TW-20, and the addition of enzyme and TW-80 to substrate at the beginning of enzyme reaction was found to most effectively increase digestibility. When TW-80 was added into either the pretreatment stage or the hydrolysis stage the digestibilities of untreated sample increased by approx 40%, whereas an increase of only 45% was observed when TW-80 was added to both stages. These results show that the addition of surfactant to either the pretreatment or the enzymatic hydrolysis stage is sufficient to increase digestibility.     

As~(3+)和As~(5+)在番茄幼苗中的吸收积累差异

利用砂培的方法,在人工气候箱内进行了As3+和As5+污染处理下的番茄幼苗的生长试验。分别设置了2、10 mg.L1两个处理质量浓度,从两片真叶时开始处理,在人工气候箱中栽培7 d后,进行取样分析植株总砷含量,并对株高、根长、鲜质量以及干质量等生长特性进行测量。结果表明,(1)砷污染下株高、鲜质量和干质量与对照相比有显著减少,表现为抑制生长的效应,并且高质量浓度时抑制效应越明显,但是根长受到的影响不大,而鲜质量和干质量都以对照为最高,并随着处理质量浓度的增加鲜质量和干质量都有减少的趋势,并且在相同质量浓度下,As3+处理与As5+处理相比,植株的鲜质量显著减少,干质量只有在高质量浓度处理下才会显著减少。(2)番茄幼苗植株对As3+和As5+的吸收积累上存在显著差异,其中As3+易于被植株吸收,相同质量浓度下的吸收量最高可达As5+的14.3倍。     

Electrodeposition of quaternary alloys in the presence of magnetic field

Electrodeposition of Ni-Co-Fe-Zn alloys was done in a chloride ion solution with the presence and absence of a Permanent Parallel Magnetic Field (PPMF). The PPMF was applied parallel to the cathode surface. The deposition profile was monitored chronoamperometrically. It was found that the electrodeposition current was enhanced in the presence of PPMF (9 T) compared to without PPMF. The percentage of current enhancement (Γ%) was increased in the presence of PPMF, with results of Γ% = 11.9%, 16.7% and 18.5% at -1.1, -1.2 and -1.3 V respectively for a 2400 sec duration. In chronoamperometry, the Composition Reference Line (CRL) for Ni was around 57%, although the nobler metals (i.e. Ni, Co) showed anomalous behaviour in the presence of Zn and Fe. The anomalous behaviour of the Ni-Co-Fe-Zn electrodeposition was shown by the Energy Dispersive X-Ray (EDX) results. From Atomic Force Microscopy (AFM) measurements, it was found that the surface roughness of the Ni-Co-Fe-Zn alloy films decreased in the presence of a PPMF.