Comparison of oil and egg tempera paint systems using time-of-flight secondary ion mass spectrometry

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is quickly becoming a critical tool in the field of art conservation. This technique provides high-resolution spatial maps of both inorganic and organic components located within cross-sectional samples collected from works of art. With recent advances in surface analysis, ToF-SIMS can now be used to identify specific amino acids present in protein-containing materials as well as fatty acids in drying oils. For example, the detection of the ion fragment associated with the amino acid hydroxyproline can be used to confirm the use of animal glue in a paint sample. As an analytical technique, ToF-SIMS avoids the need for derivatization/silylation reagents, with no interference by the presence of pigments. Furthermore, the layered systems that are often encountered in historical paint samples remain intact throughout the analytical procedure. This allows for the co-localization of organic and inorganic species in specific layers (e.g. egg yolk paint atop a glue ground). Because of this ability to localize the analytical signal to approximately 6?µm or less, the mass spectral information can be used to produce mass-resolved and spatially-resolve images which can be correlated to previous studies of the same samples. In this study, ToF-SIMS was used to analyze a paint cross section obtained from a painting attributed to Raphael, and another from a painting by the Sienese artist Matteo di Giovanni.     

鬼针草的研究现状与应用前景

针对近年来对鬼针草属植物研究的资料 ,系统总结了鬼针草药用成分分析 (细胞学、生药学、化学成分、药理学 )和品种的鉴定方法 ,同时对鬼针草资源进一步开发利用指出了更广阔的前景。     

2-（1，2-亚乙／1，3-亚丙二硫）亚甲基-3-羰基-N-芳（烷）基丁酰胺制备的新方法

以易制备的2-（1,2-亚乙／1,3-亚丙二硫）亚甲基-3-羰基丁酸1为原料,经与氯化亚砜的氯化反应后,与胺反应成功地以较好产率（40．5％-72．0％）合成重要的有机合成中间体2-（1,2-亚乙／1,3一亚丙二硫）亚甲基-3-羰基-N-芳（烷）基丁酰胺3．     

核酸四碱基体及四螺旋模型的理论构建

核酸的结构具有多态性 ,核酸的功能取决于其结构 .了解核酸不同结构的特征有利于对其功能的充分认识 .本文对核酸四碱基体及其形成的四链结构模型进行了理论研究 .这些工作有助于从理论上进一步研究核酸四螺旋结构 ,对相关的实验研究也将起到有益参考作用 .     

茭白孕茭前后植株叶片和叶鞘器官中游离氨基酸和总糖含量的变化

试验比较了“河姆渡”双季茭在孕茭前和膨大期植株叶片和叶鞘中营养成分的变化。结果表明：(1)膨大期茭白叶鞘和叶片内的总糖含量分别比孕茭前显著增加99．07%和123．79%(P＜0．05);(2)膨大期,叶鞘内总糖的含量显著大于叶片中总糖的含量,增加达18．1%(P＜0．05);(3)孕茭前和膨大期相比．茭白叶片内游离氨基酸的组成和含量无显著差异;但叶鞘内游离氨基酸的组成和含量却差异显著(P＜0．05),氨基酸总量提高了127．8%;(4)膨大期与孕茭前相比,叶鞘中有6种氨基酸的含量增幅最大,依次是：谷氨酸(Glu;610．0%)＞甘氨酸(Gly;303．6%)＞丙氨酸(Ala;228．7%)＞赖氨酸(Lys;207．2%)＞丝氨酸(Ser;203．7%)＞天门冬氨酸(Asp;172．0%);其中,丝氨酸含量最高,孕茭前和膨大期分别占氨基酸总量的34．81%和46．42%;(5)膨大期与孕茭前相比,叶片和叶鞘中脯氨酸(Pro)、精氨酸(Arg)和亮氨酸(Leu)含量均有明显降低。     

急性力竭运动对大鼠血浆支链氨基酸及氨量变影响的研究

本研究选用９ 只健康成年 Ｓ Ｄ 雄性大白鼠,采用一次性力竭游泳运动方式,通过运动前及运动后即刻从心脏取血, 测定其力竭运动前后血浆尿素氮、支链氨基酸、氨的量变情况。结果表明急性力竭性运动后大鼠血浆尿素氮、支链氨基酸、氨含量均呈明显增高, 且前两者的变化差异有显著意义（ Ｐ＜ ０． ０５）。结果提示急性力竭运动后体内蛋白质分解代谢、支链氨基酸的代谢增强,血浆氨、支链氨基酸的含量变化与运动性疲劳的出现和疲劳程度有密切关系。     

接骨木果实营养成分的分析

本文利用氨基酸自动分析仪、等离子发射光谱仪和高效液相色谱仪等仪器，对接骨木果实氨基酸含量，微量元素含量营养成分进行了测定，从而为接骨木的进一步开发利用提供了营养学方面的依据。     

Effect of low-dose omega-3 fatty acids substitution on blood pressure, hyperinsulinemia and dyslipidemia in Indians with essential hypertension: A pilot study

The present study comprised 100 patients of essential hypertension who were screened for fasting hyperinsulinemia, which was detected in 77% cases. Twenty such hyperinsulinemic cases were subjected to 4 weeks of dietary control phase followed by 6 weeks of omega-3 fatty acids substitution [either 0.6 g/d (group 1) or 1.2 g/d (group 2)]. The mean basal fasting plasma insulin levels were significantly higher (p<0.001) in patients of hypertension when compared to normal controls (126.51±80.36 and 19.35±12.61 μU/ml respectively). At the end of 4 weeks of diet control only, no significant change was observed in any parameter. After substitution of omega-3 fatty acid, a significant reduction of fasting plasma insulin levels in both group 1 (29%) and group 2 (22.8%) was observed (p<0.001). Significant reduction of systolic and diastolic blood pressure (16.4% and 25% respectively), serum cholesterol, triglycerides and low density lipoprotein was also noted in both groups (p<0.001), while high density lipoprotein increased by ∼8 mg% in both groups. Thus omega-3 fatty acid substituion in low dose along-with curtailment of dietary omega-6 fatty acid may be used as an adjunctive measure in the management of essential hypertension.     

Profile of Plasma Amino Acid Levels in Rats Exposed to Acute Hypoxic Hypoxia

The effect of acute hypoxic hypoxia on the profile of plasma amino acids in rats was studied and compared to that resulting from acute liver injury induced by giving carbon tetrachloride. In hypoxic rats exposed to 45% air in N₂ for 5 h, the concentrations of branched chain amino acids, including valine, leucine and isoleucine, and aromatic amino acids such as phenylalanine and tyrosine were significantly increased as compared to those in normoxic rats. The ratio of branched-chain to aromatic amino acids (Fischer’s ratio) was significantly decreased. The levels of arginine and citrulline, which are related to the urea cycle, were also depressed. Furthermore, plasma proline level was reduced in hypoxic rats. The activities of plasma marker enzymes for tissue damage remained unchanged during hypoxia, indicating that tissue injury was not induced by exposure to hypoxic conditions. We suggest that the characteristic profile of plasma amino acids and the Fischer ratio are valuable tools for understanding the pathology of acute hypoxia in the absence of systemic tissue damage.     

Diagnosis of Major Organic Acidurias in Children: Two Years Experience at a Tertiary Care Centre

Organic acid disorders are inherited metabolic disorders in which organic acids accumulate in tissues and biological fluids of affected individuals. Classical organic acidurias include methylmalonic aciduria, propionic aciduria, isovaleric aciduria and maple syrup urine disease (MSUD). They are considered the most frequent metabolic disorders among severely ill children. Patients frequently present with acute symptoms early in life. 420 cases clinically suspected to have organic aciduria, with upper age limit of 12 years for a 2-year period (January 2007–December 2008) were enrolled into this study. Metabolic acidosis and neurological symptoms were the most common signs. Screening tests and thin layer chromatography were done for detection of organic acidurias. Identification and quantitation of organic acids in urine and quantification of amino acids in blood were done by high performance liquid chromatography. Out of 420 patients, 45 patients (10.7%) were found to have organic acidurias. 15 cases of methylmalonic aciduria, 16 cases of propionic aciduria, 13 cases of MSUD, and one case of isovaleric aciduria were diagnosed. Results demonstrate the importance of testing for organic acidurias. Since organic aciduria may cause irreversible brain damage if not treated, we recommend selective screening amongst severely ill children despite implied extra costs.