GC/MS衍生化测定精浆中游离支链氨基酸和果糖

目的 建立人精浆中支链氨基酸和果糖的气相质谱衍生化分析方法.方法 精液样本液化离心后,按精子活率的临床标准分为正常组和非正常组,经TMS微波衍生化,GC/MS分析两组支链氨基酸、果糖衍生物含量差异.结果 正常组与非正常组的缬氨酸,亮氨酸,异亮氨酸在相对含量上均有一定差异.正常组3种氨基酸相对含量高于非正常组.果糖分析观察到同样的特征,正常组相对含量高于非正常组.结论 精子活率低的精浆样本仍可检出支链氨基酸和果糖,其差异有助于无精子、少精子精斑的法医学鉴别.     

Toward multidimensional information: A derivatization-free UHPLC-QqQ MS/MS method for amino acid components of fingerprint

The analysis of fingerprint chemical composition is a meaningful way to excavate the multidimensional information of fingerprint, including the donor profiling information and the age of a fingerprint, which broadens the evidential values of fingerprint, especially for the partial and distorted fingerprint. But the research remains still in the pilot phases or is ongoing. Amino acids are the dominant organic substances in latent sweat fingerprint and influenced by many donor factors. Hence, their content reflects personal information of donors. Forensic science will be revolutionized if suspects can be individualized by their amino acid content. The diverse nature, distinct physicochemical properties, and ultra-micro levels of amino acids present in fingerprints make it hard to detect. A high sensitivity method for detecting and quantifying multiple amino acid components is required. UHPLC-QqQ MS/MS offers high sensitivity, high separation, simultaneous multicomponents detection, and no derivatization, making it an ideal method for detecting and analyzing amino acids in fingerprints. Therefore, in this study, we propose and validate an efficient UHPLC-QqQ MS/MS method for the extraction and analysis of 13 amino acids from fingerprint. We compared the results of amino acids of 10 different substrates and found that the inherent amino acids in most porous substrates would have been extracted along with the fingerprint amino acids, making them unsuitable for quantitative amino acid analysis. Instead, plastic sheets are ideal substrates for laboratory studies. Then, extensive experiments were conducted among 30 donors for multidimensional information analysis. The type of samples analyzed were eccrine-rich fingerprints. A Binary Logistic Regression (BLR) model was developed, and the female and male donors were successfully differentiated by amino acids in fingerprints. Two other mathematical models were also developed to verify the accuracy, and all three different mathematical models were able to identify donors of different genders with over 90% accuracy. This demonstrates that amino acids have the potential to provide more information for donors as metabolic markers. In the future, we will conduct a series of experiments to analyze more multidimensional information for individual identification by amino acid content in the fingerprint.     

Moistened hands do not necessarily allude to high quality fingerprints: the relationship between palmar moisture and fingerprint donorship

We explored the quality distribution of ninhydrin-developed prints on A4 bond paper in two groups of individuals, in Israel and in India. While the quality distributions of the developed marks in both countries had some dissimilarities, both groups showed the expected bell-shape distribution, with the majority of the donors belonging to the central zone, defined as "average" or "good." Attempt was made to correlate between a physiological feature, palmar moisture, and the fingerprint donorship. As a rule, high fingermark quality could be associated with sweating hands, but there were individuals with moist palms whose fingermarks had a low score and vice versa. This finding supports the logical but hitherto unproven assumption that besides the amount of palmar sweat, the other physiological factor governing the prints' quality is the total amount of substrate, amino acids in this case, in the latent deposits, which depends on the substrate concentration in the sweat.     

氨基树脂漆的傅立叶变换红外光谱分析

根据红外谱图的相似程度决定两种涂料是否属同一种类的涂料是最基本也是最初级的检验方法,不可避免地带有极大的盲目性,只有把握了特征峰所代表的基团的振动形式,才能准确地识谱,正确地鉴别.本文介绍了氨基树脂漆的傅立叶变换红外光谱分析及谱图解释.     

A new approach to amino acid racemization in enamel: testing of a less destructive sampling methodology

Aspartic acid racemization has been found to be an accurate measure of age at death for recent forensic material. This paper examines the practicality of using acid etching of the tooth surface to extract amino acids from the enamel for racemization analysis. By serial etching of the tooth and contamination of the teeth with bovine serum albumin prior to etching, the ability of etching to remove contamination was assessed. The destructiveness of the method was visualized and quantified using micro-computed tomography (micro-CT). By bleaching the teeth and by deeper etching it was possible to obtain more consistent values. While etching had little effect on the enamel at the macroscale, it did have an impact at the microscale. The quantities of enamel removed varied depending upon the tooth morphology, but were not large. Acid etching of enamel thus appears to be a promising new method for extracting proteins for amino acid racemization age estimation noninvasively.     

Enhancement of Aged and Denatured Fingerprints Using the Cyanoacrylate Fuming Technique Following Dusting with Amino Acid‐Containing Powders

We have carried out experiments to investigate the aging of latent fingerprints deposited on black PVC over a period of 4–15 weeks. A thumbprint was used in each case and before deposition of the print the donor rubbed their thumb around their nose to add sebaceous deposits. We have studied the effect of heat, light, and moisture and we find that moisture is the most significant factor in the degradation of the latent print. We have attempted to enhance these latent prints by dusting with valine powder or powders composed of valine mixed with gold or red fluorescent commercial fingerprint powders. To make a direct comparison between “treated” and “untreated” prints, the prints were cut in half with one‐half being “treated” and one‐half not. Our studies show the best results being obtained when powders of valine and red fluorescent powders are applied prior to cyanoacrylate fuming.     

大鼠骨骼肌挫伤后ASCT2 mRNA的表达变化

目的应用实时定量PCR技术检测大鼠骨骼肌挫伤后细胞中性氨基酸载体ASCT2 mRNA表达,分析其与挫伤时间的关系。方法建立大鼠骨骼肌挫伤模型,分别取伤后4、8、12、16、20、24、28、32 h及对照组检材。提取总RNA,逆转录合成第一链的cDNA,以RPL13为内参基因进行荧光定量检测,采用2-△△Ct法比较其与对照组肌肉组织中ASCT2 mRNA的相对表达量。结果损伤组肌肉组织中ASCT2 mRNA在挫伤后12、16h表达量分别为对照组的196.40%和189.15%,损伤后4、8、20、24、28、32h ASCT2 mRNA表达量与对照组相比无统计学差异(P>0.05),说明ASCT2 mRNA在损伤12～16h其表达量较正常组及其他损伤时间组要高,而在损伤20h以后ASCT2 mRNA表达量又降至正常水平。结论大鼠骨骼肌挫伤后32h之内ASCT2 mRNA的表达有一定的时间规律性,可望作为推断骨骼肌损伤时间的指标之一。     

Thermal degradation analysis of amino acids in fingerprint residue by pyrolysis GC-MS to develop new latent fingerprint developing reagents

Conventional development of latent fingerprints is compromised when the prints are decomposed by extreme temperatures, such as those encountered when a weapon cartridge is fired, an improvised explosive device is detonated, and/or in arson cases. Understanding how these extreme temperatures alter the chemical and physical properties of latent fingerprint residue could aid in the discovery of a reagent that could effectively develop these decomposed fingerprints. To mimic scenarios where fingerprints may be exposed to high heat conditions, standards of the five most abundant amino acids in fingerprint residue as well as extracted fingerprint residue were pyrolized under controlled conditions. Compounds identified as pyrolytic decomposition products were 3,6-dimethylpiperazine-2,5-dione (from alanine), maleimide, and 2,5-furandione (from aspartic acid). The pyrograms and selected ion traces show these products to hold promise as indicators of decomposed fingerprint residues and, therefore, may serve as good candidate substrates for a developing reagent.     

Fluorescence of 1,2‐Indanedione with Amino Acids Present in the Fingerprint Residue: Application in Gender Determination

1,2‐indanedione is used for latent fingerprint visualization on porous surfaces. In this paper, fluorescence spectra of 1,2‐indanedione after reacting with 21 individual amino acids present in latent fingerprints residue were measured in water‐methanol solutions. The fluorescence intensity depends on the amino acid used, while the fluorescence peak does not change much. The concentration of amino acids in fingerprint residue in females is almost the double of their concentration in males. This property combined with fluorescence of 1,2‐indanedione‐amino acids compounds is used for gender determination, by comparing the fluorescence intensity peaks in the same experimental conditions. In this preliminary study, the fluorescence signal from the samples representing females was almost two times the signal for samples representing males. In addition to the reduction by almost 50% of the number of suspects in a criminal research case, these results could be helpful in gaining some knowledge about the papillary residue composition.     

可见分光光度法测定不同产地黄精中总氨基酸含量

目的 建立不同产地黄精中总氨基酸含量的测定方法。方法 以L-精氨酸为对照品，茚三酮为显色剂，检测波长为568 nm，采用可见分光光度法测定19个不同产地黄精中总氨基酸的含量。结果 L-精氨酸浓度在3.248～18.368 μg/mL范围内与吸光度呈现良好的线性关系（r＝0.997 5），回归方程为A＝0.084 3c－0.154 8；加样回收率为98.72%（RSD＝1.26%，n＝9）。结论 所建立的方法简单、准确、重现性好，可用于黄精中总氨基酸的含量测定。