A density gradient technique for use in forensic soil analysis

A high-density aqueous salt solution for the preparation of density gradients is presented. It has been used successfully by the authors in forensic soil analysis. It has a density range that allows for the separation of a soil specimen's heavy mineral components. It has no odor or toxic fumes, which eliminates the need to use a hood during preparation, and is far superior to the organic liquids normally used to prepare density gradients. This liquid should cause many forensic scientists to reexamine their attitudes towards using density gradients in forensic soil casework.     

An alternative method to screen for pepper spray residue

A method was developed to screen for pepper spray residue using instruments and methods other than those techniques commonly employed to analyze chemical residue (i.e.. gas chromatography mass spectrometry-GCMS or liquid chromatography mass spectrometry-LCMS). The method employed gas chromatography (GC), thin layer chromatography (TLC), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to screen for dried pepper spray stains. Pepper sprays from nine different manufacturers were investigated. Capsaicin and dihydrocapsaicin were identified and unique IR reflectance spectra are presented. An additional five compounds were presumptively found. Results showed that a particular stain could be characterized as a pepper-based stain.     

DNA双股螺旋结构与迅猛发展的法庭科学——纪念人类DNA双股螺旋结构发现50周年

自1953年Watson和Crick发表DNA双股螺旋结构,它为人类生命科学,尤其是法庭科学的发展带来了历史性的变化。法庭科学从个体识别和亲子鉴定的排除到认定,经历了DNA指纹图、AMP-FLP及SNP的3个阶段。同时线粒体DNA的应用也在广泛开展。另外数据库的建设和完善成为法庭科学的发展方向。总之,DNA双股螺旋结构对法庭科学革命性变化起了决定性的作用。     

工具理性与中国传统文化的现代化

构成西方现代性主要内涵的工具理性,促发了科学与技术的繁荣和昌盛。当前中国现代化最主要的也是最急需的就是科学与技术的大发展,这一点在文化层面上就表现为工具理性的缺失和弘扬,中国传统文化的现代化必须工具理性化。     

A Study of Background Levels of Antimony,Barium, and Lead on Vehicle Surface Samples by Graphite Furnace Atomic Absorption

Law enforcement agencies routinely sample for gunshot residue (GSR) by bulk techniques and often submit swabs taken from other surfaces besides the hands of the suspect shooter. This study aims to establish the prevalence of antimony, barium, and lead on normally handled automobile surfaces by graphite furnace atomic absorption analysis. No positives were determined on 50 sampled automobile surfaces above cutoff (positive) from background levels. Transfers of GSR particles from shooter hands to automobile surfaces were found to potentially allow for positive GSR determinations, but such transfers seem to be dependent on the shooting conditions and length of GSR exposure. We determined that our bulk analysis method yields an overall 87.94 ± 5.52% extraction efficiency from cotton swabs, while the LOQ determinations strengthening the fact that bulk analysis methods are valid and valuable tools for GSR investigations.     

浅论马丁·布伯的关系哲学——兼谈如何面对“文化冲突”

马丁·布伯在《我与你》中提出了人生与世界具有两重性：一是“为我们所用的世界”．一是“我们与之相遇的世界”．他用“我-它”公武称谓前者．用“我-你”公武称谓后者。他强调“我-你”关系的直接性、相互性和之间、相遇．并从“我-你”关系出发．重新去认知和理解世界。布怕的思想对于冷战后不同文化间越演越烈的冲突来说．仍有不可低估的现实意义。     

Case studies in forensic soil examinations

The examination and comparison of forensic soil samples is discussed. The origin of a simple and easy to learn procedure used and modified by the authors is reviewed. The process begins with a preliminary observation, removal of artifacts, and sieving of each specimen. A specific size fraction is split into three fractions for color matching, polarized light microscopy (PLM) examination (particle counting) and optional gradient comparison. Next, several cases are reviewed in which the modified method was used to evaluate the likelihood of common origin for questioned and known specimens.     

大学生关于同性恋群体态度的实证研究

研究旨在探讨大学生关于同性恋群体外显态度与内隐态度之间的联系与差异,为进一步改善同性恋生存现状奠定理论基础。研究采用问卷调查法对257名大学生进行外显态度的调查,采用内隐联想测验对内隐态度进行测验。结果显示大学生对于同性恋群体的态度在外显态度上表现得更为接纳,而在内隐态度方面人们较为排斥,即实际上人们对于这一群体仍持有负性态度。     

Surface-enhanced Raman spectroscopy for trace identification of controlled substances: Morphine, codeine, and hydrocodone

We obtain the normal Raman and surface-enhanced Raman spectrum of three controlled substances: morphine, codeine, and hydrocodone. The spectra are assigned with the aid of density functional theory. Because of rather intense fluorescence, normal Raman spectra suffer from poor signal-to-noise, even when differential subtraction techniques are employed. On the other hand, surface enhancement by Ag nanoparticles both enhances the Raman signal and suppresses the fluorescence, enabling far more sensitive detection and identification. We also present a set of discriminant bands, useful for distinguishing the three compounds, despite the similarities in their structures.     

Dr. Walter C. McCrone--his contributions to environmental microscopy

This paper briefly highlights Dr. McCrone's contributions to the recently emerging field of forensic environmental microscopy. Few, if any, criminalists are not familiar with Dr. Walter C. McCrone's voluminous contributions to the field of forensic microscopy and the analyses of micro and ultra micro transfer (trace) evidence. Dr. McCrone was renowned for his life long efforts in promoting the application of the Polarized Light Microscope (PLM) to problem solving. It is therefore not surprising that Dr. McCrone would also apply his analytical and deductive skills employing the PLM to problems in environmental analysis. He is well known for his many publications dealing with the analysis of asbestos and asbestos like materials by PLM. His philosophy of presenting intense professional training courses stressing the practical applications of the PLM carried over to a series of courses offered to students requiring education in other areas of microscopical analysis. Through McCrone Research Institute, Dr. McCrone can be said to have been responsible for the training of a large majority of microscopists who literally analyzed tens of millions of samples. These analyses were performed utilizing methodologies developed predominately by him and adopted by regulatory agencies in the United States and abroad. The methods he fostered are a major part of the arsenal of microscopical techniques employed by forensic environmental microscopists in their efforts to identify a manufacturer of an insulation product for the purpose of litigation.