N-cyanomethyl-N-methyl-1-(3',4'-methylenedioxyphenyl)-2-propylamine: an MDMA manufacturing by-product

This paper describes the structural elucidation of a compound produced during the synthesis of 3,4-methylenedioxymethylamphetamine (MDMA) via the reductive amination of 3,4-methylenedioxyphenyl-2-propanone (3,4-MDP-2-P) with methylamine and sodium cyanoborohydride. The compound was isolated from MDMA by column chromatography, proton and carbon nuclear magnetic resonance spectroscopy, LC/mass spectrometry, and total synthesis were used to identify the compound as N-cyanomethyl-N-methyl-1-(3',4'-methylenedioxyphenyl)-2-propylamine. This compound has been identified as a potential synthetic route marker for the reductive amination of 3,4-MDP-2-P with methylamine and sodium cyanoborohydride and as such it should prove valuable to forensic scientists engaged in profiling illicit drugs. Profiling MDMA can provide useful information to law enforcement agencies relating to synthetic route, precursor chemicals and reagents employed and may be used for comparative analyses of different drug seizures. This paper also describes the structural elucidation of the analogous methylamphetamine synthetic route marker compound, N-cyanomethyl-N-methyl-1-phenyl-2-propylamine, produced during the reductive amination of phenyl-2-propanone using methylamine and sodium cyanoborohydride.     

大鼠死后脑组织的傅里叶变换红外光谱变化

目的应用傅里叶变换红外（Fourier transform infrared．FTIR）光谱技术分析大鼠死后脑组织随死亡时间推移的化学变化过程,为死亡时间推断的研究提供新的途径与数据。方法大鼠断颈处死后置于（30±2）℃环境下,在不同时间点提取大鼠脑皮质．运用FTIR光谱仪检测不同化学基团的变化。结果随着死亡时间的推移,大鼠脑组织FTIR光谱的主要吸收峰峰位没有明显变化．而其峰强有明显差异：（1）与核酸有关的谱带的相对峰强呈明显下降趋势;（2）酰胺Ⅰ、Ⅱ的峰强比（I1647/I1541）呈下降趋势;（3）1456和1398cm^-1谱带的峰强各自呈下降和上升趋势;（4）2852、2871、2923和2958cm^-1谱带的峰强相对于1647cm^-1而言．呈上升趋势。结论脑组织可以作为FTIR光谱技术分析死亡时间的适用检材。     

Fourier transform infrared reflectance spectra of latent fingerprints: a biometric gauge for the age of an individual

To determine if changes in fingerprint infrared spectra linear with age can be found, partial least squares (PLS1) regression of 155 fingerprint infrared spectra against the person's age was constructed. The regression produced a linear model of age as a function of spectrum with a root mean square error of calibration of less than 4 years, showing an inflection at about 25 years of age. The spectral ranges emphasized by the regression do not correspond to the highest concentration constituents of the fingerprints. Separate linear regression models for old and young people can be constructed with even more statistical rigor. The success of the regression demonstrates that a combination of constituents can be found that changes linearly with age, with a significant shift around puberty.     

增信措施担保化的反思与重构——基于我国司法裁判的实证研究

我国司法实践中关于差额补足、流动性支持等增信措施有保证合同说、无名合同说、债务加入说和对赌协议说四种学说构造。从《民法典担保制度解释》第36条的上下文看,该条文的内容有可能导致司法实践中将增信措施解释为保证合同。但增信措施的运用领域复杂多样,应根据其交易结构、交易习惯和行为目的进行意思表示解释。在结构化金融和信托管理计划中使用增信措施,并不存在被担保的主债权,不需要按照保证合同解释。资产管理业务中的增信措施起到合法的保底作用,也不宜解释为保证合同。即使在一般的金融交易领域,增信措施有避免担保被计入企业财务报告、上市公司信息披露、保证合同各项限制性规则等意义,于此应尊重当事人的意思自治,将增信措施解释为独立的无名合同。如果增信措施的保证意思表示明显,则当然要适用保证的规则。如果增信措施被解释为无名合同而非保证,也可以考虑类推适用保证合同的规则,包括保证合同主体资格的限制、保证合同的书面形式、公司对外担保的决议,以及保证中的债权转让或债务人变更的后果等规则。但是,关于保证的从属性、保证责任范围、一般保证推定、保证期间、保证人援引主债务人抗辩事由等规则,不宜类推适用。     

使用危险化学品实施放火案件的物证检验1例

随着科技的发展,分析仪器在刑事技术领域的应用越来越广泛,有时往往会忽视对传统化学分析方法的应用。作为检验无机粉末的常用仪器,扫描电镜/能谱仪(SEM/EDS)和X射线衍射仪(XRD)受检出限的影响,无法准确分析样品中的低含量组分。本文在一起危险化学品放火案件检验中,为确定样品中含S元素的物质种类,利用化学分析法对其进行沉淀富集,再使用SEM/EDS和XRD检验,确认其中含有KMnO4和KHSO4,推测嫌疑人使用KMnO4和浓H2SO4等危险化学品实施放火,这在日常工作中比较罕见。通过总结相关工作经验,可为类似案事件的预防、物证提取和检验提供新的思路。     

基于亮度感知权重的夜间图像去雾技术

目的对夜间雾天环境下成像设备获取的图像进行去雾和图像增强处理,以便给公安机关的图像侦查工作提供直观的侦查信息。方法首先基于夜间大气散射物理模型,采用通道差引导的低通滤波器估计环境照度;其次使用亮通道和暗通道先验分别估算图像中光源区和非光源区的环境透射率,然后采用一种亮度感知权重的方式将二者融合得出最终的混合环境透射率;最后对夜间大气模型公式进行求解获得去雾图像。在此基础上使用CLAHE和SoG算法对图像视觉效果进行增强。结果经过对大量实际案例和计算机合成的夜间雾天图像进行处理,实验结果表明本文采用的去雾与图像增强技术在客观评价方面:偏色检测因子降低65%、平均梯度提高233%、信息熵提高7%,相较于其他主流方法均占显著优势;在主观评价方面:本文方法能同时提升图像颜色动态范围、矫正图像偏色、增强图像暗部细节。结论基于亮度感知权重的夜间去雾与图像增强技术能够有效增强夜间雾天图像的暗部细节、提高图像对比度和解决图像偏色问题,能为公安机关的图像侦查工作提供更直观有效的信息。     

The effect of household corrosive substances on latent fingermark development in the context of deliberate corrosive substance attacks

Corrosive substance attacks (CSA) are a prevalent issue in the UK with 525 offenses involving a corrosive substance reported to the police in the year ending March 2022. Easy availability, low cost, and concealability in public are common reasons for choosing a corrosive substance as a weapon. The Metropolitan Police revealed that 68% of 1849 CSA cases resulted in no suspect identified or evidential difficulties. There is limited research into the effect of corrosive substances on latent fingermarks. This study aimed to determine the potential for fingermarks to be recovered from surfaces exposed to a household corrosive substance within the context of a deliberate CSA. Natural and sebaceous-loaded fingermarks were exposed to Domestos bleach, Harpic limescale remover (hydrochloric acid-based) and lemon juice. Harpic limescale remover had the most detrimental effect, with only 7.1% of fingermarks (n = 378) exposed being identifiable (defined as sufficient clear ridge detail for identification) after enhancement, followed by bleach with only 10.3% of fingermarks (n = 378) identifiable. Lemon juice had the least detrimental effect on fingermarks, with 40.5% fingermarks (n = 378) identifiable compared to 53.4% for the controls (not exposed to any substance; n = 378). Throughout the study, fewer natural fingermarks were identifiable after exposure to corrosive substances compared to sebaceous fingermarks which was as expected. Overall, this study demonstrated that there is potential to recover latent fingermarks, depending on their composition, following exposure to a household corrosive substance. This area warrants further research to establish best practice to maximize the potential to recover identifiable fingermarks.     

Preliminary investigations into tris(2,2'-bipyridyl) ruthenium III as a chemiluminescent reagent for the detection of 3,6-diacetylmorphine (heroin) on surfaces

The use of tris(2,2'-bipyridyl) ruthenium (III) as a chemiluminescent spray reagent spot-test for heroin is discussed. Two forms of the reagent are investigated an aqueous and an anhydrous where both were found to give vastly different results. The aqueous reagent giving slow, low intensity chemiluminescence whilst the anhydrous reagent gave a fast, bright response in the presence of 3,6-diacetylmorphine. The anhydrous reagent is less sensitive the slow, intensity response is characteristic of only two opiates tested 3,6-diacetylmorphine and 3-monoacetylmorphine.     

Neonatal death following clozapine self-poisoning in late pregnancy: an unusual case report

The report presents a fatal poisoning of a neonate occurring in the final stage of gestational life and evoked by his mother, who, while 9 months pregnant, took a toxic dose of clozapine aiming at committing suicide. She was also severely poisoned, but ultimately was saved. The woman had been taking the medication due to schizophrenia and depression prior to conception, and the discontinuation of the drug in the course of pregnancy increased the risk of the woman attempting suicide. In the course of comprehensive toxicological analysis based on the developed analytical procedure with the use of LC-APCI-MS, clozapine and its two metabolites, norclozapine and clozapine-N-oxide, were determined in postmortem blood, liver and kidney in concentrations explaining the death of the neonate. The interpretation of the above-described case is complex and--apart from toxicological aspects--also involves issues associated with psychiatry, pharmacotherapy in pregnancy and medicolegal problems.     

气相色谱-负化学源质谱法检测生物样品中佐匹克隆

目的建立气相色谱-负化学源质谱检验生物样品中佐匹克隆的方法。方法采用OasisHLB柱进行固相萃取,NCI-GC／MS检验。结果生物样品中佐匹克隆平均萃取回收率达75．8％,最低检出限0．01μg·mL^-1,线性良好,相关系数R^2=0．9989。结论该方法操作简便快速,提取回收率高,重现性好,提取物干净,可用于实际案件。