Comparison of gasolines using gas chromatography-mass spectrometry and target ion response

Gas chromatography-mass spectrometry was used to compare gasoline samples obtained from different sources based on the difference in amounts of certain components found in the headspace of gasoline using target response data. Many suspected arson cases involve comparing an ignitable liquid extracted from fire debris to a liquid found in a suspect's possession to determine if they could have had a common source. Various component ratios are proposed for determining if an unevaporated gasoline sample could have originated from the same source as an evaporated gasoline extracted from fire debris. Fifty and 75% evaporated gasoline samples were both found to contain similar ratios of certain components when compared with its unevaporated source gasoline. The results of the comparisons in this study demonstrate that for cases involving gasoline that has been evaporated up to 50% and extracted from pine, it is possible to eliminate comparison samples as originating from the same source. The results of the 75% comparisons suggest it may be possible to apply the same type of comparison to cases involving 75% evaporated gasoline.     

Analysis of artificial fireplace logs by high temperature gas chromatography

High temperature gas chromatography is used to analyze the wax of artificial fireplace logs (firelogs). Firelogs from several different manufacturers are studied and compared. This study shows that the wax within a single firelog is homogeneous and that the wax is also uniform throughout a multi-firelog package. Different brands are shown to have different wax compositions. Firelogs of the same brand, but purchased in different locations, also have different wax compositions. With this information it may be possible to associate an unknown firelog sample to a known sample, but a definitive statement of the origin cannot be made.     

Injury Patterns Sustained in Fatal Motor Vehicle Collisions with Driver's Third‐Generation Airbag Deployment

The Office of the Chief Coroner for Ontario database for 2011–2012 was used to compare fatal injury patterns in drivers whose third‐generation airbags deployed compared to first‐ and second‐generation airbag deployments and airbag nondeployments with and without seatbelt use. There were 110 frontal and offset frontal crashes analyzed. The small sample size meant that the odds of craniocerebral, cervical spinal, thoracic, and abdominal injuries were not statistically different for airbag generation, deployment status, and seatbelt use; however, the risk of fatal thoracic injuries in third‐ and second‐generation cases was increased. Seatbelt usage in third‐ and second‐generation deployment cases reduced the risk of all injuries except abdominal trauma. High severity impacts and occupant compartment intrusion were frequently observed. The analyses in this retrospective study were challenged by data that were not collated in a standardized way and were limited in details about scene, vehicle, and driver variables.     

Democratic Party Control Reduces Gender Inequality

Women earn less than men who work in the same job with the same level of experience. We know much about this gender wage gap but relatively little about its political or partisan sources. In this article, we examine the effects of party control of state government on gender inequality in income, wages, unemployment, and poverty. Employing both a regression discontinuity design and a dynamic difference‐in‐difference analysis, we find that electing a Democratic majority to the state house leads to substantial improvement in women's incomes, wages, and unemployment relative to men—especially in recent years. We also show that greater female representation in office and more liberal policymaking on policies related to women's rights could be driving that process. We find, however, fewer clear effects on poverty and less robust results for partisan control of the governor's office or the state senate. Parties and politics matter, but not always.     

Facial Soft Tissue Thickness Database for Craniofacial Reconstruction in Korean Adults

Abstract: One hundred Korean adults (50 men, 50 women) were scanned in the upright position using a cone‐beam CT (CBCT) scanner. The soft tissue (ST) thicknesses were measured at 31 landmarks, 10 midline and 21 bilateral landmark sites, and the means and standard deviations were obtained for male and female subjects. While 18 of 31 landmarks showed sex differences, the majority showed higher values for male subjects with the exception of a few landmark sites corresponding to the zygoma area, which showed smaller values in men than in women. The mandibular area showed greater differences between the right and left sides. Overall, the ST thickness measurements obtained in this study can be used as a database for the forensic craniofacial reconstruction of Korean adult faces.     

Extraction of alternative fuels from fire debris samples*

Alternative fuels, specifically biodiesel, biodiesel blends, and E85 fuel, have been gaining a market share over the past few years. With the emergence of these fuels, fire debris analysts should be able to recognize their characteristics since these fuels may be encountered in casework. In this study, pure biodiesel (B100) and a 20% blend of pure biodiesel with petroleum diesel (B20) are examined as liquids and are extracted from debris samples using both passive headspace concentration and solvent extraction. Typical fire debris instrumental conditions are used to analyze these samples. Components of B100 and B20 may be observed in debris samples extracted using the passive headspace concentration method, but the chromatographic patterns are different from the pure liquid samples. When solvent extraction is used as a secondary extraction method on debris samples, the resulting patterns are consistent with the pure liquids of B100 and B20. E85 fuel, a blend of 85% ethanol and 15% gasoline, can be extracted using a typical fire debris extraction technique but requires slight modifications to typical fire debris instrumental conditions. E85 is shown at various stages of evaporation to demonstrate the resiliency of the ethanol. Additionally, samples of E85 were placed on carpet, burned and extinguished to demonstrate the effects of the suppression medium on the retention of ethanol.