美韩同盟再定义与韩国的战略选择:进程与争论

本文系统总结了自2002年底以来美韩同盟再定义的磋商过程,以及双方在驻韩美军基地调整、同盟内部军事安全角色分工、同盟的未来战略构想等三大焦点问题上所取得的实质性进展,认为通过区域扩展和内涵扩展的路径选择,美韩同盟再定义已基本实现利益平衡与威胁平衡的双重目标。通过对美韩全球性战略同盟关系的定位与确认,韩国也由此结束了数年来激烈的外交方向辩论,再度确立了中近期亲美的结盟外交路线,然而有关韩国对外战略的争论不会就此终结。     

平衡、融合与引导——试析新世界秩序构建中的中国作用

频繁的世界危机凸显出全球化时代下国际问题不可阻挡的跨国溢出与无序的世界治理秩序之间的深刻矛盾。从能源到气候变化问题,从大规模杀伤性武器的扩散到传染性疾病的防治,从国际金融系统的稳定到跨国宏观经济协调,政治、经济、安全问题复杂交织,世界越来越陷入动荡不安之中。当前处于世界新秩序重构的重要转型时期,中国不断增加的国家实力、声望和影响力赋予其在世界新秩序的构建中举足轻重的地位。本文旨在阐述中国在新秩序构建中的力量平衡、制度融合与理念引导作用。     

Practical benzylation of N,N-substituted ethanolamines related to chemical warfare agents for analysis and detection by electron ionization gas chromatography–mass spectrometry

The benzylation of three low molecular weight N,N-disubstituted ethanolamines related to chemical warfare agents (CWAs) to furnish derivatives with improved gas chromatography-mass spectrometry (GC-MS) profiles is described. Due to their low molecular weight and polar nature, N,N-disubstituted ethanolamines are notoriously difficult to detect by routine GC-MS analyses during Organisation for the Prohibition of Chemical Weapons (OPCW) proficiency tests (PTs), particularly in scenarios when they are present at low levels (~1–10 ppm) amidst more abundant interferences. Our studies revealed that the optimal derivatization conditions involved the treatment of the ethanolamine with benzyl bromide in the presence of an inorganic base (e.g., Na₂CO₃) in dichloromethane at 55°C for 2 h. This optimized set of conditions was then successfully applied to the derivatization of N,N-dimethylethanolamine, N,N-diethylethanolamine and N,N-diisopropylethanolamine present separately at 1 and 10 μg/mL concentrations in a glycerol-rich matrix sample featured in the 48th OPCW PT. The benzylated derivatives of the three ethanolamines possessed retention times long enough to clear the massive glycerol-containing matrix interferences. The protocol herein is introduced as an alternative method for derivatization of these CWA and pharmaceutically important species and should find broad applicability in laboratories where routine forensic analysis is carried out.     

A statistical approach to aid examiners in the forensic analysis of handwriting

We develop a statistical approach to model handwriting that accommodates all styles of writing (cursive, print, connected print). The goal is to compute a posterior probability of writership of a questioned document given a closed set of candidate writers. Such probabilistic statements can support examiner conclusions and enable a quantitative forensic evaluation of handwritten documents. Writing is treated as a sequence of disjoint graphical structures, which are extracted using an automated and open-source process. The graphs are grouped based on the similarity of their shapes through a K-means clustering template. A person's writing pattern can be characterized by the rate at which graphs are emitted to each cluster. The cluster memberships serve as data for a Bayesian hierarchical model with a mixture component. The rate of mixing between two parameters in the hierarchy indicates writing style.     

Collecting touch DNA from glass surfaces using different sampling solutions and volumes: Immediate and storage effects on genetic STR analysis

Touch DNA has become increasingly important evidence in todays' forensic casework. However, due to its invisible nature and typically minute amounts of DNA, the collection of biological material from touched objects remains a particular challenge that underscores the importance of the best collection methods for maximum recovery efficiency. So far, swabs moistened with water are often utilized in forensic crime scene investigations for touch DNA sampling, even though an aqueous solution provokes osmosis, endangering the cell's integrity. The aim of the research presented here was to systematically determine whether DNA recovery from touched glass items can be significantly increased by varying swabbing solutions and volumes compared with water-moistened swabs and dry swabbing. A second objective was to investigate the possible effects of storage of swab solutions prior to genetic analysis on DNA yield and profile quality when stored for 3 and 12 months, as is often the case with crime scene samples. Overall, the results indicate that adapting volumes of the sampling solutions had no significant effect on DNA yield, while the detergent-based solutions performed better than water and dry removal, with the SDS reagent yielding statistically significant results. Further, stored samples showed an increase in degradation indices for all solutions tested, but no deterioration in DNA content and profile quality, allowing for unrestricted processing of touch DNA samples stored for at least 12 months. One further finding was a strong intraindividual change in DNA amounts observed over the 23 deposition days which may be related to the donor's menstrual cycle.     

Evaluating expertise in forensic anthropology

The medicolegal system relies on the ability of experts and non-experts alike to make judgments about expertise and use those judgments to reach consequential decisions. Given the lack of standard criteria, mandatory certification, or licensure for establishing expertise required to practice forensic anthropology and testify as an expert witness, we sought to understand how individuals assess and identify expertise in forensic anthropology by using a social science tool called the Imitation Game. This tool assesses immersion in a specific area of study via discourse, with the premise that some individuals lacking expertise themselves imitate or attempt to pass as experts. For this project we recruited volunteers with varying expertise in forensic anthropology to participate in interviews which asked questions about the practice and structure of the discipline. Those interviews were transcribed, anonymized, and evaluated by other recruited individuals with varying expertise in forensic anthropology. Results found that judges who were experts in forensic anthropology performed better than non-expert judges in determining who was not an expert in forensic anthropology based on their anonymized responses; however, nearly half of the non-experts were still able to pass as experts in forensic anthropology. The difficulties in assessing expertise based on discourse interactions demonstrates the value and need for well-defined credentials and mandatory certification to practice forensic anthropology. This study demonstrates that accurately identifying expertise in forensic anthropology may be challenging for both experts and non-experts, especially when relying solely on interactional expertise rather than formal assessments of competency which directly elucidate contributory expertise.     

Detection of methamphetamine in mouse femurs exposed to high temperature

Bone samples are valuable for examining the cause of death and circumstance leading up to death when body fluids are not available for forensic toxicological analysis. Examined were heat-induced changes in methamphetamine and amphetamine concentrations in femurs removed from methamphetamine-injected mice to determine if the burned bones could be used for toxicology testing. The femurs were heated at 100°C, 300°C, or 500°C for 10 or 30 min. The tissue structure of the heated femurs was preserved at 100°C for 30 min but was destructed at higher temperatures. Methamphetamine and amphetamine were detected in femurs heated at 100°C for 10 min, 100°C for 30 min, and 300°C for 10 min (with methamphetamine and amphetamine concentrations ranging from 0.36 to 35 μg/g and 0.54 to 47 μg/g, respectively). Methamphetamine and amphetamine were detectable when heated above their decomposition temperature as a result of limited heat transfer do to protection provide by the femoral muscle. Thus, the bone could be a useful analytical sample in cases of burn-related deaths, where it is difficult to collect body fluids.     

Modification of the Marmarou and Foda model of diffuse axonal injury (DAI) improves percentage survival of rats at 24 h and increases the amount of DAI identified

More than two decades ago, Marmarou published a valid model for producing diffuse axonal injury (DAI) in rats. Since then, both mild and severe injuries have been obtained by researchers using the original method and a weight of 450 g. However, the diffuse brain injuries produced in rats were only similar to those seen in humans when the rats sustained severe brain injuries. In these cases, rat mortality in the original article was around 50%, and the cause of death was prolonged apnea post-impact. Rat survival after impact is critical for studying the progression of DAI. In order to explain the cause of death in human victims with cranial trauma who do not show gross brain injury, testing for the presence of DAI is essential. Thus, in order to minimize local and cervical injuries to increase rat survival, attention should be paid to the following aspects: a wider head protector disc should be used, the head of the rat should be elevated at the time of impact, and the foam bed should be soft enough to allow the movement caused by acceleration. With our modified method, rat survival increased by 30% compared to the original model (80% versus 50%). Moreover, 85.7% of rats demonstrated DAI after 24 h of survival. With these modifications, injuries appear in the same locations as in humans; thus, the method is suitable for the study of traumatic DAI in humans.     

Alternative direct-to-amplification cell lysis techniques for forensically relevant non-sperm cells

While efforts have been made to reduce the pervasive backlog of sexual assault evidence collection kits, the actual laboratory process remains very time-consuming due to the requirement of a differential lysis step before DNA purification, as well as intricate mixture analysis towards the end of the DNA workflow. Recently, an alternative, direct-to-amplification sperm lysis method (using 1 M NaOH) was identified. However, a direct cell lysis method for non-sperm cells has not been identified yet. Thus, the primary objective of this work was to find an alternative method that is quick, inexpensive, and does not require multiple purification steps for the lysis of non-sperm cells in sexual assault samples. In this study, vaginal swab samples were lysed with the control method, prepGEM™, as well as six alternative reagents: alkaline buffer with 25–200 mM NaOH, high-salt stain extraction buffer, modified radioimmunoprecipitation assay (RIPA) buffer, mammalian protein extraction reagent (M-PER™), digitonin buffer, and urea/thiourea buffer. Quantification using Quantifiler® Trio of vaginal and semen lysates revealed that the alkaline (25 mM NaOH) and M-PER™ methods were efficient for the lysis of vaginal epithelial cells without substantial sperm cell lysis. Following quantification, analysis of STR profiles from vaginal lysates revealed that the M-PER™ method showed promising results across all metrics examined, including the percentage of detected STR alleles, mean peak heights, peak height ratio, and interlocus balance. Thus, this method was recommended as an alternative to the traditional differential lysis method for non-sperm cells given its ability to produce amplification-ready lysates without any DNA purification step.