The Contribution of Body Mass and Volume of Distribution to the Estimated Uncertainty Associated with the Widmark Equation

The Widmark equation is used forensically for the determination of the amount of ethanol (alcohol) that may have been consumed and also to determine the blood alcohol concentration (BAC) of an individual at a specific time. It is important to be able to estimate the uncertainty associated with Widmark equations. To date, there has been no detailed determination of contribution to the final uncertainty of Widmark calculations of the volume of distribution of ethanol (V_d), using anthropometric equations, or the contribution of an individual’s body mass. Using published data, published literature, and freedom of information data, we determined that the variability (%CV) associated with V_d was ~10% (Watson et al. and Forrest anthropometric equations) and that the %CV associated with estimated body mass was ~15% compared to ~3% when body mass was directly measured. These data allow an estimation of the overall uncertainty of Widmark calculations using general error propagation. The estimated total uncertainty for BAC calculations increased from ~11% (volume consumed) and ~22% (BAC) to ~19% (volume consumed) and ~37% (BAC) when using measured body mass compared to estimated body mass. These results demonstrate that forensic practitioners should be mindful of the increase in estimated uncertainty in calculated Widmark equation results when estimated body mass is used rather than measured body mass. These data further improve the knowledge around the uncertainty of results calculated with the Widmark equation.     

Reflections on variability in the blood–breath ratio of ethanol and its importance when evidential breath-alcohol instruments are used in law enforcement

Variability in the blood–breath ratio (BBR) of alcohol is important, because it relates a measurement of the blood-alcohol concentration (BAC) with the co-existing breath-alcohol concentration (BrAC). The BBR is also used to establish the statutory BrAC limit for driving from the existing statutory BAC limits in different countries. The in-vivo BBR depends on a host of analytical, sampling and physiological factors, including subject demographics, time after end of drinking (rising or falling BAC), the nature of the blood draw (whether venous or arterial) and the subject’s breathing pattern prior to exhalation into the breath analyzer. The results from a controlled drinking study involving healthy volunteers (85 men and 15 women) from three ethnic groups (Caucasians, Hispanics and African Americans) were used to evaluate various factors influencing the BBR. Ethanol in breath was determined with a quantitative infrared analyzer (Intoxilyzer 8000) and BAC was determined by headspace gas chromatography (HS-GC). The BAC and BrAC were highly correlated (r = 0.948) and the BBR in the post-absorptive state was 2 382 ± 119 (mean ± SD). The BBR did not depend on gender (female: 2 396 ± 101 and male: 2 380 ± 123, P > 0.05) nor on racial group (Caucasians 2 398 ± 124, African Americans 2 344 ± 119 and Hispanics 2 364 ± 104, P > 0.05). The BBR was lower in subjects with higher breath- and body-temperatures (P < 0.05) and it also decreased with longer exhalation times into the breath-analyzer (P < 0.001). In the post-absorptive state, none of the 100 subjects had a BBR of less than 2 100:1.     

Forensic appraisal of death due to acute alcohol poisoning: three case reports and a literature review

Death due to acute alcohol poisoning lacks specific anatomical characteristics, compared with other deaths due to drug poisoning. We report three forensic cases of death from acute alcohol poisoning due to inhibition of the respiratory centre and eventual asphyxia. Blood alcohol concentrations in the three fatalities were 5.28, 3.33 and 3.78 mg/mL, respectively. Lethal doses and blood alcohol concentrations showed differences between individuals. Detailed auxiliary tests besides autopsy were undertaken. These cases show that forensic scientists should exclude other causes of death, combine the autopsy with auxiliary tests, and then make an appraisal.     

Characteristics of Drug Vendors on the Tor Network: A Cryptomarket Comparison

Abstract

Past research on drug-related vendors on Tor marketplaces indicate that sellers are motivated by the greater anonymity afforded by the Tor Network. Limited research has even posited that some drug-related vendors on cryptomarkets sell to other dealers, adding another dimension to existing literature that highlights the retail nature (dealer-to-customer transactions) of these Tor-based drug markets. Yet these past studies have been largely qualitative in nature. This study conducted a quantitative analysis of vendor accounts on Evolution and Agora to determine characteristics predictive of vendors advertising controlled substances, and to determine whether any statistically significant differences among drug vendor characteristics existed between the two sites.     

Developing Citizens: Missed Opportunities in Health and Social Service Provision? A View From Aotearoa New Zealand

This article is a reflection on an evaluation of multisystemic therapy services in Aotearoa New Zealand, established to treat young people aged 12–16, for alcohol and drug misuse and to decrease unwanted or “antisocial” behaviors. The therapy engaged parents/caregivers in a systems approach and did not require the young person to be directly engaged. This raised three issues. First, because the young people were not active participants, the services missed the opportunity to help the young people develop skills of self management. Second, this lack of engagement created a missed opportunity to engage the young person to re-establish or reconnect relationships that had been harmed. Finally, we reflect on the cultural fit of the service with Māori values. These issues raise a number of questions about the aims of service provision with young people and the assumptions that underpin particular types of service.     

白头翁汤正丁醇提取物对白念珠菌作用下Caco-2细胞中细胞因子、防御素及Toll样受体表达的影响

目的 从细胞因子、人β- 防御素（human beta defensin，HBD）及Toll样受体（toll- like receptors，TLRs）途径探究白头翁汤正丁醇提取物（butyl alcohol extract of Baitouweng Decoction，BAEB）抗白念珠菌的机制。方法 以Caco- 2细胞为实验模型，先以BAEB作用Caco- 2细胞24 h，再加入热灭活的白念珠菌SC5314孢子(Candida albicans，C.A)共培养24 h，以MTT法测定Caco- 2细胞存活率；采用酶联免疫吸附试验检测Caco- 2细胞上清液白细胞介素- 6（interleukin- 6, IL- 6）、IL- 8、IL- 1β、HBD- 2、HBD- 3水平；采用普通PCR法检测Caco- 2细胞TLR1、TLR2、TLR4、TLR5 mRNA的表达水平。结果 与对照组比较，C.A单独作用的Caco- 2细胞中IL- 6、IL- 8、IL- 1β、HBD- 2、HBD- 3表达水平显著升高（P<0.05），TLR1、TLR2、TLR4、TLR5 mRNA表达水平显著上调（P<0.05）；与C.A单独作用相比，BAEB预保护Caco- 2细胞后，Caco- 2细胞中IL- 6、IL- 8、IL- 1β及HBD- 2、HBD- 3表达水平明显降低（P<0.05），TLR1、TLR2、TLR4、TLR5 mRNA表达水平也显著下调（P<0.05），BAEB高剂量的效应最明显。结论 BAEB抗白念珠菌的机制与下调细胞因子、HBD及TLRs表达有关。