气-质联用法（EI．PCI．NCI）在系统毒物分析中的应用

本文应用电子轰击质谱(EI),正、负化学电离质谱(PCI.NCI)技术,建立了315种常见毒,药物的气一质联用系统分析方法。并建立了 EIMS、PCIMS、NCIMS 质谱图谱库。司法鉴定实践表明使用气相保留指数,特征碎片和 EI、PCI、NCI 图谱库检索等多指标的系统分析方法,是未知物鉴定的强有力的工具。     

Carbon‐Based Fingerprint Powder as a One‐Step Development and Matrix Application for High‐Resolution Mass Spectrometry Imaging of Latent Fingerprints

Carbon‐based materials are often used as matrices for matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) and its imaging (MALDI‐MSI). However, researchers have refrained from using carbon‐based fingerprint powder (CFP) as a matrix due to high background and contamination. In this work, the compatibility of CFP is reevaluated with MALDI‐MSI using a high‐resolution mass spectrometer (HRMS) and compared to traditional organic matrices. Relevant fingerprint compounds were easily distinguished from carbon cluster peaks when using HRMS. For fair comparison, half of a fingerprint was dusted with CFP while the other half was dusted with traditional organic matrices. All compounds studied had comparable, or higher, signal‐to‐noise (S/N) ratios when CFP was used as the matrix. Additionally, chemical image qualities closely followed the trend of S/N ratios. CFP proved to be an effective one‐step development and matrix application technique for MALDI‐MSI of latent fingerprints, when carbon cluster peaks are well separated by a HRMS.     

Alprazolam and Zolpidem in Skeletal Tissue of Decomposed Body Confirms Exposure

In several medico‐legal cases, bone samples analysis may provide the only source of toxicological information. This case study reports the analysis of a human bone specimen, belonging to a 46‐year‐old man, found 3 months after his death due to cervical–thoracic injuries in a motorcycle accident. Bone specimen was the only available material for toxicological analysis, among few skull hair and rotten skin. Analysis was performed by a newly developed and validated ultra‐high‐pressure liquid chromatography–mass spectrometry/mass spectrometry (UHPLC‐MS/MS) method, following simple and efficient sample pretreatment. The results were in accordance with the man's medical record: Alprazolam and zolpidem were found at 2.2 and 5.4 ng/g of bone, respectively. Both these drugs were prescribed to the deceased.     

Race,Place, and Police-Caused Homicide in U.S. Municipalities

We test structural hypotheses regarding police-caused homicides of minorities. Past research has tested minority threat and community violence hypotheses. The former maintains that relatively large minority populations are subjectively perceived as threats and experience a higher incidence of police-caused homicide than whites do, the latter that higher rates of violent crime among minorities create objective threats that explain these disparities. That research has largely ignored some important issues, including: alternative specifications of the minority threat hypothesis; the place hypothesis, which maintains highly segregated minority populations are perceived as especially threatening by police; and police-caused homicide in the Hispanic population. Using data for large U.S. cities, we conducted total-incidence and group-specific analyses to address these issues. A curvilinear minority threat hypothesis was supported by the Hispanic group-specific findings, whereas the place hypothesis found strong support in both total and group-specific analyses. These results provide new insights into patterns of police-caused homicide.     

Evaluating the Role of Race in Sentencing: An Entropy Weighting Analysis

The current study builds on prior research examining racial disparities in sentencing. Entropy weighting is introduced as a new method for estimating racial disparities that has several advantages over traditionally used methods. Entropy weighting is compared to regression and propensity score methods in estimating Black-White disparities in incarceration sentences. Although all methods find non-significant racial disparities in incarceration sentences, regression and propensity score methods underestimate disparities in incarceration sentence lengths. Entropy weighting provides comparable estimates to propensity score methods, but assures that the samples are identical on all covariates aside from race. The method offers researchers a useful and flexible approach for estimating racial disparities in criminal justice, and its use may lead to alternative conclusions about the size and presence of racial disparities in sentencing.     

Secondary transfer of organic gunshot residues: Empirical data to assist the evaluation of three scenarios

The present study aimed at providing data to assess the secondary transfer of organic gunshot residues (OGSR). Three scenarios were evaluated in controlled conditions, namely displacing a firearm from point A to point B, a simple handshake and an arrest involving handcuffing on the ground. Specimens were collected from the firearm, the hands of the shooter and the non-shooter undergoing the secondary transfer in order to compare the amounts detected.Secondary transfer was observed for the three scenarios, but to a different extent. It was found that displacing a firearm resulted in secondary transfer in <50% of the experiments. The firearm also had an influence, as contrary to the pistol, no secondary OGSR were detected using the revolver. Shaking the hand of the shooter also transferred OGSR to the non-shooter's hand. In that case, the amount of OGSR was generally higher on the shooter than on the non-shooter. Finally, the largest secondary transfer was observed after the arrest with handcuffing with positive results in all cases using the pistol. In that scenario, the amounts on the shooter and the non-shooter were in the same range.This study highlights that the secondary transfer must be taken into account in the interpretation of OGSR. Indeed, an individual's hands might be contaminated by handling a firearm or having physical contact with a shooter.     

Race/ethnicity,citizenship status,and crime examined through trauma experiences among young adults in the United States

Race/ethnicity, citizenship status, and trauma, have significant impact on delinquency and crime outcomes; though the reasons for some expected and unexpected crime pathways are still unanswered. Using data from the National Longitudinal Survey of Youth 1997 (n?=?7,103), this study found the following results: no difference in the likelihood of engagement in delinquency and crime between blacks and whites; cumulative trauma increased delinquency and crime rates for all racial and ethnic groups; racial and ethnic minority groups compared to whites reported a significantly higher level of childhood trauma experiences; and native-born female immigrant groups (but not male) were more likely to engage in delinquency and crime than first-generation female immigrant groups. Implications and recommendations are set forth.     

INTERORGANIZATIONAL UTILITY OF WELFARE STIGMA IN THE CRIMINAL JUSTICE SYSTEM*

The appropriation of “welfare stigma” or stereotypes about poor people's overreliance and abuse of public aid in two core criminal justice functions is examined: felony adjudication in a court system and space allocation in a jail. Through a comparative ethnographic study in which an abductive analysis of data (20 months of fieldwork) was used, we show that criminal justice gatekeepers utilize welfare stigma to create stricter eligibility criteria for due process in criminal courts and occupancy in jails. Specifically, the number of court appearances, motions, trials, jail beds, food, showers, and medical services is considered by professionals to be the benefits that individuals seek to access and abuse. Professionals view their role as preventing (rather than granting) access to these resources. The comparative nature of our data reveals that welfare stigma has interorganizational utility by serving two different organizational goals: It streamlines convictions in courts, which pulls defendants through adjudication, and conversely, it expands early release from jails, which pulls inmates out of the custody population. In the context of diminishing social safety nets, our findings have implications for understanding how discretion is exercised in an American criminal justice system increasingly tasked with the distribution of social services to the urban poor.     

STREET NETWORK STRUCTURE AND CRIME RISK: AN AGENT‐BASED INVESTIGATION OF THE ENCOUNTER AND ENCLOSURE HYPOTHESES

Street networks shape day‐to‐day activities in complex ways, dictating where, when, and in what contexts potential victims, offenders, and crime preventers interact with one another. Identifying generalizable principles of such influence offers considerable utility to theorists, policy makers, and practitioners. Unfortunately, key difficulties associated with the observation of these interactions, and control of the settings within which they take place, limit traditional empirical approaches that aim to uncover mechanisms linking street network structure with crime risk. By drawing on parallel advances in the formal analyses of street networks and the computational modeling of crime events interactions, we present a theoretically informed and empirically validated agent‐based model of residential burglary that permits investigation of the relationship between street network structure and crime commission and prevention through guardianship. Through the use of this model, we explore the validity of competing theoretical accounts of street network permeability and crime risk—the encounter (eyes on the street) and enclosure (defensible space) hypotheses. The results of our analyses provide support for both hypotheses, but in doing so, they reveal that the relationship between street network permeability and crime is likely nonlinear. We discuss the ramifications of these findings for both criminological theory and crime prevention practice.     

Quantitative Determination of Cannabinoids in Cannabis and Cannabis Products Using Ultra‐High‐Performance Supercritical Fluid Chromatography and Diode Array/Mass Spectrometric Detection

Ultra‐high‐performance supercritical fluid chromatography (UHPSFC ) is an efficient analytical technique and has not been fully employed for the analysis of cannabis. Here, a novel method was developed for the analysis of 30 cannabis plant extracts and preparations using UHPSFC /PDA ‐MS . Nine of the most abundant cannabinoids, viz . CBD , ?⁸‐THC , THCV , ?⁹‐THC , CBN , CBG , THCA ‐A, CBDA , and CBGA , were quantitatively determined (RSD s < 6.9%). Unlike GC methods, no derivatization or decarboxylation was required prior to UHPSFC analysis. The UHPSFC chromatographic separation of cannabinoids displayed an inverse elution order compared to UHPLC . Combining with PDA ‐MS , this orthogonality is valuable for discrimination of cannabinoids in complex matrices. The developed method was validated, and the quantification results were compared with a standard UHPLC method. The RSD s of these two methods were within ±13.0%. Finally, chemometric analysis including principal component analysis (PCA ) and partial least squares‐discriminant analysis (PLS ‐DA ) were used to differentiate between cannabis samples.