Recent trends in an uncommon method of carbon monoxide suicide.

PURPOSE: The most prevalent method of carbon monoxide (CO) suicide is inhalation of vehicle exhaust (VE). However, a new method of CO suicide has recently emerged involving charcoal burning (CB) in a confined space to produce fatal CO levels. This method has been reported from countries in Asia, associated with economic instability and media reporting of high-profile celebrity cases. The current study was undertaken to analyze rates and characteristics of CB suicides in South Australia (SA) for comparison with respect to their characteristics and scene, autopsy and toxicology findings. METHODS: A search was undertaken for all intentional fatal carbon monoxide poisonings in SA between 2000 and 2019. Collected variables included age, sex, cause of death, location of death, decedent histories, scene, autopsy and toxicology findings and manner of death. Statistical analyses were performed using R (version 4.2.3). RESULTS: There was a significant decrease in VE suicides (p < 0.05) and a significant increase in CB suicides (p < 0.001) over the 20-year period. Those who used CB were found to be, on average, between 1.5 and 15.8 years younger than those who used VE (p = 0.017). The risk factors for CB suicide included psychological/psychiatric conditions and financial problems, while VE suicides were associated with a history of physical problems and contact with the legal system. External and internal autopsy findings were consistent with the literature. CONCLUSION: CB suicide is perceived to be widely accessible and painless and is therefore becoming a popular suicide method. Monitoring future trends will be important to determine whether intervention is required.

Diagnostic models to predict nuclear DNA and mitochondrial DNA recovery from incinerated teeth.

Teeth are frequently used for human identification from burnt remains, as the structure of a tooth is resilient against heat exposure. The intricate composition of hydroxyapatite (HA) mineral and collagen in teeth favours DNA preservation compared to soft tissues. Regardless of the durability, the integrity of the DNA structure in teeth can still be disrupted when exposed to heat. Poor DNA quality can negatively affect the success of DNA analysis towards human identification. The process of isolating DNA from biological samples is arduous and costly. Thus, an informative pre-screening method that could aid in selecting samples that can potentially yield amplifiable DNA would be of excellent value. A multiple linear regression model to predict the DNA content in incinerated pig teeth was developed based on the colourimetry, HA crystallite size and quantified nuclear and mitochondrial DNA. The chromaticity a* was found to be a significant predictor of the regression model. This study outlines a method to predict the viability of extracting nuclear and mitochondrial DNA from pig teeth that were exposed to a wide range of temperatures (27 to 1000 °C) with high accuracy (99.5-99.7%).

Prescribed and Diverted Methadone Toxicity in South Australia: An Update.

ABSTRACT: Methadone is one of the most common medications currently prescribed for the treatment of opioid use disorders (OUDs). While methadone maintenance programs (MMPs) have been highly successful in the management and treatment of OUDs resulting in a reduced number of fatalities, the risk of overdose/toxicity remains. The current study was undertaken to analyze trends in overdoses attributed to prescribed and diverted methadone in South Australia (SA) between 2000 and 2019. Over the 20-year period, 344 methadone-related deaths occurred in SA with a significant increase in deaths over the study period ( P = 0.03). The mean age of decedents was 42.5 years with a male to female ratio of 1.8:1, with approximately 20% of decedents enrolled in a MMP at the time of death. Overall, only 5.2% of cases demonstrated methadone diversion, which was associated with methadone prescribed for chronic pain and was most likely to be diverted from a friend/housemate or a partner. However, the source of methadone in more than half of cases was unknown, so this is likely a significant underestimate of actual MMP methadone diversion and total methadone diversion.

Fatal blunt chest trauma: an evaluation of rib fracture patterns and age.

The following study was undertaken to determine if any specific occupant characteristics, crash factors, or associated injuries identified at autopsy could predict the occurrence or number of fractured ribs in adults. Data were accrued from the Traffic Accident Reporting System (TARS) and coronial autopsy reports from Forensic Science SA, Adelaide, South Australia, from January 2000 to December 2020. A total of 1475 motor vehicle fatalities were recorded in TARS between January 2000 and December 2020, and 1082 coronial autopsy reports were identified that corresponded to TARS fatal crash data. After applying exclusion criteria involving missing data, 874 cases were included in the analysis. Of the 874 cases, 685 cases had one or more rib fractures. The leading cause of death for those with rib fractures was multiple trauma (54%), followed by head injury (17%) and chest injuries (10%). The strongest predictor of one or more rib fractures was increasing age (p < 0.001). Other factors found in the regression to be predictive of the number of rib fractures were the presence of a variety of other injuries including thoracic spinal fracture, lower right extremity fracture, splenic injury, liver injury, pelvic fracture, aortic injury, lung laceration, and hemothorax. Age is most likely associated with increasing rib fractures due to reduced tolerance to chest deflection with greater injuries occurring at lower magnitudes of impact. The association of other injuries with rib fractures may be a marker of higher impact severity crashes.

Prediction of Retention Time and Collision Cross Section (CCSH+, CCSH-, and CCSNa+) of Emerging Contaminants Using Multiple Adaptive Regression Splines.

Ultra-high performance liquid chromatography coupled to ion mobility separation and high-resolution mass spectrometry instruments have proven very valuable for screening of emerging contaminants in the aquatic environment. However, when applying suspect or nontarget approaches (i.e., when no reference standards are available), there is no information on retention time (RT) and collision cross-section (CCS) values to facilitate identification. In silico prediction tools of RT and CCS can therefore be of great utility to decrease the number of candidates to investigate. In this work, Multiple Adaptive Regression Splines (MARS) were evaluated for the prediction of both RT and CCS. MARS prediction models were developed and validated using a database of 477 protonated molecules, 169 deprotonated molecules, and 249 sodium adducts. Multivariate and univariate models were evaluated showing a better fit for univariate models to the experimental data. The RT model (R2 = 0.855) showed a deviation between predicted and experimental data of ±2.32 min (95% confidence intervals). The deviation observed for CCS data of protonated molecules using the CCSH model (R2 = 0.966) was ±4.05% with 95% confidence intervals. The CCSH model was also tested for the prediction of deprotonated molecules, resulting in deviations below ±5.86% for the 95% of the cases. Finally, a third model was developed for sodium adducts (CCSNa, R2 = 0.954) with deviation below ±5.25% for 95% of the cases. The developed models have been incorporated in an open-access and user-friendly online platform which represents a great advantage for third-party research laboratories for predicting both RT and CCS data.

Success of Low Aromatic Fuel in Preventing Gasoline Sniffing Deaths.

ABSTRACT: Gasoline (petrol) sniffing is a form of volatile substance misuse that is particularly prevalent within Australian indigenous communities. Although epidemiological studies have shown that gasoline sniffing has decreased over recent years, rates of gasoline sniffing deaths have not been widely reported. Therefore, a study was undertaken to assess the association between the implementation of low aromatic fuel (LAF) and gasoline sniffing deaths. All cases of fatal gasoline sniffing in South Australia between 2000 and 2019 were identified from the Toxicology Database and autopsy reports at Forensic Science South Australia. Furthermore, previous studies of gasoline sniffing deaths were assessed to provide historical context and approximate rates of gasoline sniffing deaths before the current study. The rate of gasoline sniffing deaths decreased significantly ( P = 0.039) over the study period concomitant to an increase in the number of LAF sites nationally. Although not supported by findings of statistical significance because of the small number of cases, this study provides further supportive evidence for the effectiveness of LAF by showing a significant associated decrease in local rates of gasoline sniffing deaths.

Increasing use of sodium nitrite in suicides-an emerging trend.

Sodium nitrite (NaNO2) is a compound with broad practical applications in food preservation, automotive maintenance, and animal control. Sodium nitrite is also potentially fatal when ingested, as it interferes with the ability of red blood cells to transport oxygen. While incidents of accidental consumption have been reported in the literature, case reports of sodium nitrite being used as a pharmacological suicide agent are becoming more frequent. Therefore, a study was undertaken to evaluate trends in sodium nitrite deaths in South Australia between 2000 and 2019. All cases of fatal sodium nitrite ingestion were identified in the Toxicology database and autopsy reports at Forensic Science SA (FSSA). Ten cases of fatal sodium nitrite ingestion were identified, with the rate of cases increasing significantly over the study period (p > .001). Of the ten deaths attributed to sodium nitrite toxicity, eight were male, and two were female. The age range of decedents was 22-74 years (mean 51.9, SD 21.1), 22-74 years for males (mean 58.4, SD 18.2) and 23-29 years for females (mean 26.0, SD 4.2). Males (80%) and those with a history of depression and/or suicidal ideation (70%) were over-represented within the study population. While autopsy findings were generally consistent with the literature, scene findings emphasized the accessibility of sodium nitrite to the general public. This study highlights both a significant increasing trend in the use of sodium nitrite in suicides and important analytical limitations in the evaluation of suspected cases.

Characteristics of fatal insulin overdoses.

This study was undertaken to review fatal cases of insulin overdose in South Australia (SA) over a 20-year period to assess rates and characteristics of insulin-related deaths among insulin-dependent diabetics and non-diabetics for all manners of death. Records from the National Coronial Information System (NCIS) and Forensic Science SA (FSSA) were searched for all cases of fatal insulin overdose in South Australia (SA) between 2000 and 2019. Collected variables included age, sex, cause of death, scene findings, manner of death, decedent medical and personal histories, biochemistry, toxicology, histopathology, and autopsy findings. Statistical analyses were performed using R (version 4.1.2). Forty cases of insulin overdose were identified in SA between 2000 and 2019. Twenty-nine cases (72.5%) were suicides, with the remaining cases classified as accidental or undetermined intent. Thirteen of the 22 insulin-dependent diabetics (59%) had a history of depression, 10 of whom had previously demonstrated suicidal ideation. The current study has shown that suicides using insulin among insulin-dependent diabetics are equally as prevalent, if not more so than fatal accidental insulin overdoses. This can largely be attributed to insulin-dependent diabetic access to a potentially lethal substance. Suicide prevention strategies should focus on insulin-dependent diabetics with a history of depression, particularly for those with access to rapid-acting insulin.

Cardiac disease and driver fatality.

To determine the role of cardiac disease in driver fatalities, a retrospective review of autopsy files at Forensic Science SA in Adelaide, Australia, was undertaken over a 13-year-period January 2005-December 2017 for individuals aged ≥ 40 years who had died while driving a motor vehicle. The incidence of significant coronary artery atherosclerosis (CAA) and cardiomegaly was evaluated with comparisons between drivers and a control group of passengers. Autopsy examinations were performed on 303 drivers and 72 passengers who died of trauma and on 63 drivers who died of a cardiac event while driving. The average age for drivers dying of trauma was 58.5 years (range 40-93 years) with 48 (15.8%) having CAA and 31 (10.2%) having cardiomegaly. This was not statistically different to passengers (aged 63.3 years; range 40-93 years; 20.8% having CAA; 11 (15.2%) cardiomegaly; (p > 0.2). Drivers with significant cardiac disease did not, therefore, have increased rates of death in crashes, although a distinct subgroup of drivers consisted of those who had died from cardiac events and not trauma, while driving. The latter may be increasing in number given the aging population.

The development of a tool to predict temperature-exposure of incinerated teeth using colourimetric and hydroxyapatite crystal size data.

This study presents a novel tool to predict temperature-exposure of incinerated pig teeth as a proxy for understanding impacts of fire on human teeth. Previous studies on the estimation of temperature-exposure of skeletal elements have been limited to that of heat-exposed bone. This predictive tool was developed using a multinomial regression model of colourimetric and hydroxyapatite crystal size variables using data obtained from unheated pig teeth and teeth incinerated at 300 °C, 600 °C, 800 °C and 1000 °C. An additional variable based on the observed appearance of the tooth was included in the tool. This enables the tooth to be classified as definitely burnt (600 °C-1000 °C) or uncertain (27 °C/300 °C). As a result, the model predicting the temperature-exposure of the incinerated teeth had an accuracy of 95%. This tool is a holistic, robust and reliable approach to estimate temperature of heat-exposed pig teeth, with high accuracy, and may act as a valuable proxy to estimate heat exposure for human teeth in forensic casework.

Mental and physical health impairments at the transition to college: Early patterns in the education-health gradient.

Part of the education-health gradient may be related to inequalities in the transition from high school to college by health impairment status. In this paper, we use the National Longitudinal Survey of Youth 1997 to investigate the link between health impairments beginning prior to high school completion and college-going, distinguishing between individuals with mental, physical, or multiple health impairments and between enrollment in 2-year and 4-year postsecondary institutions. We find that individuals with mental impairments or multiple impairments are less likely to initially enroll in 4-year postsecondary institutions than individuals without health impairments, controlling on background and high school preparation. We also find evidence that advanced math course-taking in high school, an important step on the pathway to a 4-year college for all students, does not provide students with mental impairments the same return as students without health impairments. We discuss implications for policy to address educational inequalities in health.

Evaluation of Monitoring Schemes for Wastewater-Based Epidemiology to Identify Drug Use Trends Using Cocaine, Methamphetamine, MDMA and Methadone.

Wastewater-based epidemiology is increasingly being used as a tool to monitor drug use trends. To minimize costs, studies have typically monitored a small number of days. However, cycles of drug use may display weekly and seasonal trends that affect the accuracy of monthly or annual drug use estimates based on a limited number of samples. This study aimed to rationalize sampling methods for minimizing the number of samples required while maximizing information about temporal trends. A range of sampling strategies were examined: (i) targeted days (e.g., weekends), (ii) completely random or stratified random sampling, and (iii) a number of sampling strategies informed by known weekly cycles in drug use data. Using a time-series approach, analysis was performed for four drugs (MDMA, methamphetamine, cocaine, methadone) collected through a continuous sampling program over 14 months. Results showed, for drugs with weekly cycles (MDMA, methamphetamine and cocaine in this sample), sampling strategies which made use of those weekly cycles required fewer samples to obtain similar information as sampling 5 days per week and had better accuracy than stratified random sampling techniques.

Undermatched? School-based Linguistic Status, College Going, and the Immigrant Advantage.

Considerable research investigates the immigrant advantage, yet little work examines the influence of school-based linguistic status. Contradictory patterns exist: research identifies both an immigrant advantage and a language minority disadvantage in college going. Although not all immigrant youth are language minorities, many do speak a language other than English. Educators in U.S. schools group immigrant students into three discrete linguistic categories: native English speakers, language minorities not in ESL, and English learner (EL) students. We employ multivariate methods to investigate immigrant college going by linguistic status using the Educational Longitudinal Study of 2002. Results suggest an immigrant advantage only among the two immigrant groups not in ESL, and evidence of undermatching-wherein students choose post-secondary options for which they are over prepared-among high achieving EL students. Expanded understanding of the immigrant advantage might improve EL students' pathways into college, stemming this loss of human capital.

Increased incidence of mixed drug toxicity deaths involving tapentadol - A forensic study.

Tapentadol is a relatively new synthetic opioid analgesic prescribed for the management of moderate to severe pain. While tapentadol has been shown to be more effective than traditional opioid analgesics, it still carries the risk of addiction, abuse, and misuse. In Australia, tapentadol has become one of the top five most commonly prescribed opioid drugs, with prescriptions increasing by approximately 150,000 each year since it first became available. The rapid increase in tapentadol prescriptions has occurred in parallel to an increasing number of post-mortem tapentadol detections in South Australia (SA). While the number of deaths in SA related to tapentadol use was low in the current study, findings suggest that an increasing trend of deaths involving tapentadol will continue in parallel to a rapidly increasing number of prescriptions, mirroring trends associated with traditional opioids in SA. As a comparatively new opioid analgesic, monitoring future trends will be important to determine if additional prescribing education, intervention, or restrictions are required.

Capturing functional connectomics using Riemannian partial least squares.

For neurological disorders and diseases, functional and anatomical connectomes of the human brain can be used to better inform targeted interventions and treatment strategies. Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique that captures spatio-temporal brain function through change in blood-oxygen-level-dependent (BOLD) signals over time. FMRI can be used to study the functional connectome through the functional connectivity matrix; that is, Pearson's correlation matrix between time series from the regions of interest of an fMRI image. One approach to analysing functional connectivity is using partial least squares (PLS), a multivariate regression technique designed for high-dimensional predictor data. However, analysing functional connectivity with PLS ignores a key property of the functional connectivity matrix; namely, these matrices are positive definite. To account for this, we introduce a generalisation of PLS to Riemannian manifolds, called R-PLS, and apply it to symmetric positive definite matrices with the affine invariant geometry. We apply R-PLS to two functional imaging datasets: COBRE, which investigates functional differences between schizophrenic patients and healthy controls, and; ABIDE, which compares people with autism spectrum disorder and neurotypical controls. Using the variable importance in the projection statistic on the results of R-PLS, we identify key functional connections in each dataset that are well represented in the literature. Given the generality of R-PLS, this method has the potential to investigate new functional connectomes in the brain, and with future application to structural data can open up further avenues of research in multi-modal imaging analysis.

Features of fatal pesticide ingestion in South Australia.

Pesticides are used to kill, repel or control any animal or plant species which are considered pests, but have also been associated with intentional and unintentional human fatalities. A rapid increase in pesticide suicides was observed during 'The Green Revolution' after pesticides were introduced into low- and middle-income rural households without appropriate guidelines for safe use and storage. While national pesticide bans have contributed to a significant decrease in pesticide-related suicides, such cases still comprise a large proportion of all suicides around the world. The aim of the current study was to provide a profile of pesticide suicides in a high-income country as a point of comparison against studies from low- and middle-income countries. Statistical analyses were performed using R (version 4.2.3). Over the 20-year study period, there were a low, yet consistent number of pesticide suicides which were most common among males over the age of 40. Paraquat and methomyl pesticides collectively contributed to almost half (48.8%) of all fatalities. Consistent with the literature, such cases often occurred with little premeditation in response to an acute emotional crisis. While interpretation of autopsy findings was mostly limited, there were some pesticides that demonstrated findings consisted with previously reported characteristics (e.g., gastroesophageal erosions with paraquat). Given the high proportion of cases where paraquat and methomyl pesticides were implicated, it may be appropriate to review the availability and accessibility of such compounds to reduce the occurrence of pesticide suicides in South Australia and potentially the wider Australian population.

Seat belt injuries and external markings at autopsy in cases of lethal vehicle crashes.

A study was undertaken to determine what injuries are associated with the wearing of seat belts and if the presence of cutaneous seat belt markings observed on victims of lethal vehicle crashes increased the likelihood of underlying injury. Autopsy reports from the files at Forensic Science South Australia were reviewed for all fatal motor vehicle crashes from January 2014 to December 2018. A total of 173 cases were included for analysis with 127 occupants wearing seat belts at the time of impact (73.4%) (age range = 18-93; mean = 45 M:F = 81:46). Of these, only 38 had external seat belt markings (29.9%) (age range = 19-83; mean = 49 M:F = 20:18). Logistic regression modelling showed that occupants who were wearing seat belts were more likely to experience closed head injury without skull fractures in addition to mesenteric and gastrointestinal injury. Increasing body mass index increased the incidence of seat belt markings (p < 0.01) and markings were more likely to be found in the presence of bilateral pelvic fractures. Thus, external seat belt markings were observed in only a minority of seatbelt wearers, and more often in individuals with higher BMIs and with bilateral pelvic fractures (possibly associated with greater momentum and impact force).

Characteristics of analytically confirmed gamma-hydroxybutyrate (GHB) positive patients in the emergency department: presentation, poly-drug use, disposition and impact on intensive care resource utilisation.

BACKGROUND: Gamma-hydroxybutyrate is a potent central nervous system depressant with a narrow recreational dose window and analytical detection time. We describe data relating to intoxicated patients presenting to emergency departments across metropolitan Adelaide who tested positive for gamma-hydroxybutyrate. This work was part of the Emergency Department Admission Blood Psychoactive Testing study. METHODS: Over a 15-month period, patients presenting to four metropolitan emergency departments with symptoms of drug intoxication were enrolled in the study. The methodology involved the collection of demographic and clinical data and a de-identified blood sample which underwent comprehensive toxicological analysis. Gamma-hydroxybutyrate was determined using an acid-catalysed cyclisation followed by liquid-liquid extraction and gas chromatography-mass spectrometry. Data relating to samples positive for gamma-hydroxybutyrate were examined. RESULTS AND DISCUSSION: A total of 1120 patients were enrolled between March 2019 and May 2020, 309 of whom were positive for gamma-hydroxybutyrate (27.6%). Of these, 256 (83%) were also positive for metamfetamine (methamphetamine). The most common clinical observation in gamma-hydroxybutyrate-positive patients was central nervous system depression (89%). There was a significant relationship between gamma-hydroxybutyrate status and sex; although males outnumbered females in absolute terms, a higher proportion of females (32%) tested positive for gamma-hydroxybutyrate than males (25%, P = 0.0155). Blood gamma-hydroxybutyrate concentrations ranged from 10 to 651 mg/L (0.096-6.2 mmol/L) and increasing gamma-hydroxybutyrate concentration correlated with severe toxicity. The presence of gamma-hydroxybutyrate had a significant impact on the patient discharge destination: the majority (69.2%) of gamma-hydroxybutyrate-positive patients were managed and discharged from the emergency department or their attached short stay wards. A significantly higher proportion of gamma-hydroxybutyrate-positive patients were admitted to the intensive care unit (28.2%) compared with gamma-hydroxybutyrate-negative patients (12.7%, chi-squared = 36.85, P <0 .001). Gamma-hydroxybutyrate positive cases accounted for 45.8% of all study-related intensive care unit admissions. CONCLUSIONS: Gamma-hydroxybutyrate is commonly detected in illicit drug-related emergency department presentations and is detected disproportionately in the patient cohort who require intensive care unit level care.

Exploring Bias in Math Teachers' Perceptions of Students' Ability by Gender and Race/Ethnicity.

This study explores whether gender stereotypes about math ability shape high school teachers' assessments of the students with whom they interact daily, resulting in the presence of conditional bias. It builds on theories of intersectionality by exploring teachers' perceptions of students in different gender and racial/ethnic subgroups, and advances the literature on the salience of gender across contexts by considering variation across levels of math course-taking in the academic hierarchy. Utilizing nationally representative data from the Education Longitudinal Study of 2002 (ELS), analyses reveal that disparities in teachers' perceptions of ability that favored white males over minority students of both genders are explained away by student achievement in the form of test scores and grades. However, we find evidence of a consistent bias against white females which, although relatively small in magnitude, suggests that teachers hold the belief that math is easier for white males than it is for white females. We also find some evidence of variation across course level contexts with regard to bias. We conclude by discussing the implications of our findings for research on the construction of gender inequality.

A multivariate extension to the standard 4σ criterion for comparison of forensic glass evidence.

This manuscript presents a more accurate and easy to implement multivariate generalisation of the international standard 4σ forensic glass comparison technique. Many crimes result in glass breaking, and the broken glass found at a crime scene can be important forensic evidence. The chemical composition of this glass can be measured to establish whether it can be distinguished from glass fragments found on a suspect's clothing. The chemical composition can be measured using laser ablation-inductively coupled plasma mass spectrometry. A commonly used method to compare fragments of glass is the 4σ interval criterion. This method, however, compares each element individually and does not take advantage of the multivariate nature of this data. We introduce a multivariate extension to this method, which makes use of the correlation structure between the elements. We demonstrate that this method results in an improvement in the false positive rate, with only a small compromise in the false negative rate. The improvement in false positive rate is desirable as false positives translate to misleading evidence against a potentially innocent defendant. The multivariate generalisation improves accuracy while retaining a similar interpretation, and so is suitable to present in court.