The use of machine learning for the determination of a type/model of firearms by the characteristics on cartridge cases.

Cartridge cases are commonly collected at crime scenes involving firearms. One of the stages in forensic examination is the determination of the type and model of firearms based on the class characteristics of these cartridge cases. A firearm examiner evaluates the class characteristics on the basis of their knowledge and experience, and by referring to collections of cartridge cases representing class characteristics of different firearms, special databases and reference books. However, this process is highly subjective. The novelty of this research is in developing objective methods of firearms determination by applying a machine learning approach. In this study, several Convolutional Neural Networks from Keras programming package were trained to determine the type/model of a firearm based on the class characteristics observed on cartridge cases from seven different categories of firearms. The prediction accuracies received by this method range from 71 to 81 percent for models based on different Convolutional Neural Networks, while using an ensemble of the machine learning models increased the accuracy to 88 %. The research demonstrates the efficacy of machine learning in enhancing accuracy and reducing subjectivity in firearm identification, highlighting its significant potential in forensic science applications.

Machine learning applications in forensic DNA profiling: A critical review.

Machine learning (ML) is a range of powerful computational algorithms capable of generating predictive models via intelligent autonomous analysis of relatively large and often unstructured data. ML has become an integral part of our daily lives with a plethora of applications, including web, business, automotive industry, clinical diagnostics, scientific research, and more recently, forensic science. In the field of forensic DNA, the manual analysis of complex data can be challenging, time-consuming, and error-prone. The integration of novel ML-based methods may aid in streamlining this process while maintaining the high accuracy and reproducibility required for forensic tools. Due to the relative novelty of such applications, the forensic community is largely unaware of ML capabilities and limitations. Furthermore, computer science and ML professionals are often unfamiliar with the forensic science field and its specific requirements. This manuscript offers a brief introduction to the capabilities of machine learning methods and their applications in the context of forensic DNA analysis and offers a critical review of the current literature in this rapidly developing field.

Post-COVID Interstitial Lung Disease and Other Lung Sequelae.

As the world emerges from the COVID-19 pandemic, clinicians and researchers across the world are trying to understand the sequelae in patients recovered from COVID-19 infection. In this article, the authors review post-acute sequelae of SARS-COV-2, interstitial lung disease, and other lung sequelae in patients recovering from COVID-19 infection.

Enhancing Analytical Reasoning in the Intensive Care Unit.

Clinical reasoning is prone to errors in judgment. Error is comprised of 2 components-bias and noise; each has an equally important role in the promulgation of error. Biases or systematic errors in reasoning are the product of misconceptions of probability and statistics. Biases arise because clinicians frequently rely on mental shortcuts or heuristics to make judgments. The most frequently used heuristics are representativeness, availability, and anchoring/adjustment which lead to the common biases of base rate neglect, misconceptions of regression, insensitivities to sample size, and fallacies of conjunctive, and disjunctive events. Bayesian reasoning is the framework within which posterior probabilities of events is identified. Familiarity with these mathematical concepts will likely enhance clinical reasoning. Noise is defined as inter or intraobserver variability in judgment that should be identical. Guidelines in medicine are a technique to reduce noise.

Touch DNA recovery from unfired and fired cartridges: Comparison of swabbing, tape lifting and soaking.

Over the recent few years, several DNA collection techniques and methodologies have been published for the recovery of DNA from fired cartridge cases. In this study, swabbing, the DNA collection technique currently used in our jurisdiction (NSW, Australia), was compared with tape lifting and soaking to assess DNA recovery rates, DNA quality and profile quality. Brass .22LR and 9mmP cartridges were used as they are the most commonly encountered in our jurisdiction. The cartridges (n = 107) were loaded into cleaned firearm magazines by three volunteers of unknown shedder status, to mimic routine casework sample types. Half of the handled cartridges were fired whilst the other half were kept unfired. STR genotypes were produced at both 29 and 30 PCR cycles to evaluate which improved handler allele detection. DNA recovery rates showed that swabbing recovered significantly less DNA than tape lifting and soaking. Whilst there were no significant differences between tape lifting and soaking, tape lifting, on average, yielded more DNA than soaking. The calibre of ammunition had no influence on DNA recovery and in line with expectations, firing was found to decrease DNA recovery for all three sampling techniques. Assessment of DNA quality showed no evidence of PCR inhibition in any of the samples for this study. However, degradation indices showed that most samples were slightly to moderately degraded. Fewer handler alleles were detected from both fired tape lifted and soaked cartridges than unfired cartridges. Whilst 30 amplification cycles allowed for the detection of slightly more handler alleles, no statistically significant differences were found between 29 and 30 PCR cycles. Nonetheless, 50% of the profiles from unfired soaked cartridges that were non-uploadable after 29 cycles were uploadable after 30 cycles. Furthermore, 83% of profiles from unfired cartridges that were tape lifted were uploadable onto our jurisdiction's database at both 29 and 30 PCR cycles. All magazine controls, despite cleaning, contained some level of background DNA. Furthermore, increasing the number of PCR cycles to 30 also increased the detection of non-handler alleles in DNA profiles. Our results suggest tape lifting yields more uploadable profiles from unfired and fired cartridge cases than swabbing but also more adventitious (non-handler) alleles. However additional research will be needed to evaluate the full potential of this method.

Patient selection and preoperative evaluation of percutaneous dilation tracheostomy in the intensive care unit.

Percutaneous dilation tracheostomy (PDT) is increasingly performed at the bedside of critically ill patients in the intensive care unit (ICU). PDT is safe overall and has a number of benefits compared to surgical tracheostomy. A tracheostomy tube has numerous advantages compared to an endotracheal tube, including decreased work of breathing, ease of connecting to a mechanical ventilator, improved patient comfort and pulmonary hygiene. Common patient populations include those unable to wean from mechanical ventilation, those requiring enhanced pulmonary hygiene, and those with progressive neuromuscular weakness. Clinicians performing this procedure should be familiar with common indications for performing tracheostomy as well as absolute and relative contraindications. Special patient populations, including those with morbid obesity, aberrant anatomic and vascular anatomy, cervical spine injury, and high ventilatory requirements, should be approached with careful planning. Pre-procedure evaluation for coagulopathy, including basic laboratory analysis and medication review, should be undertaken. Pre-procedure ultrasound may be used to more accurately identify landmarks and vascular structures. The optimal timing for performing PDT is unknown and depends on the unique characteristics of each patient, perceived natural history of the disease process being addressed and open conversations with the patient or surrogate decision maker. In this review, we identify patient populations most likely to benefit from PDT and outline data behind optimal timing, pre-procedural laboratory evaluation and patient specific factors that may influence procedural success.

Extracorporeal Membrane Oxygenation with Right Ventricular Assist Device for COVID-19 ARDS.

BACKGROUND: Right ventricular failure is an underrecognized consequence of COVID-19 pneumonia. Those with severe disease are treated with extracorporeal membrane oxygenation (ECMO) but with poor outcomes. Concomitant right ventricular assist device (RVAD) may be beneficial. METHODS: A retrospective analysis of intensive care unit patients admitted with COVID-19 ARDS (Acute Respiratory Distress Syndrome) was performed. Nonintubated patients, those with acute kidney injury, and age > 75 were excluded. Patients who underwent RVAD/ECMO support were compared with those managed via invasive mechanical ventilation (IMV) alone. The primary outcome was in-hospital mortality. Secondary outcomes included 30-d mortality, acute kidney injury, length of ICU stay, and duration of mechanical ventilation. RESULTS: A total of 145 patients were admitted to the ICU with COVID-19. Thirty-nine patients met inclusion criteria. Of these, 21 received IMV, and 18 received RVAD/ECMO. In-hospital (52.4 versus 11.1%, P = 0.008) and 30-d mortality (42.9 versus 5.6%, P= 0.011) were significantly lower in patients treated with RVAD/ECMO. Acute kidney injury occurred in 15 (71.4%) patients in the IMV group and zero RVAD/ECMO patients (P< 0.001). ICU (11.5 versus 21 d, P= 0.067) and hospital (14 versus 25.5 d, P = 0.054) length of stay were not significantly different. There were no RVAD/ECMO device complications. The duration of mechanical ventilation was not significantly different (10 versus 5 d, P = 0.44). CONCLUSIONS: RVAD support at the time of ECMO initiation resulted in the no secondary end-organ damage and higher in-hospital and 30-d survival versus IMV in specially selected patients with severe COVID-19 ARDS. Management of severe COVID-19 ARDS should prioritize right ventricular support.

The impact of a cardiopulmonary resuscitation video on reducing surrogates' anxiety: A pilot randomized controlled trial.

PURPOSE: To test the primary hypothesis that a CPR video will reduce ICU patients' surrogates' anxiety when deciding code status, as measured by the Hamilton Anxiety Rating (HAM-A) Scale, as compared to the no video group. MATERIALS AND METHODS: This is a prospective randomized control trial. Twenty-seven ICU patients' surrogates were enrolled in the study after receiving an ICU team-led code status discussion. After the enrollment, twelve surrogates were randomized to the video group and fifteen to the no video group. The primary outcome of anxiety was quantified using the HAM-A Scale. Demographic information, clinical data, and patients' provenance information (Home vs. Not Home) were collected. The patients' severity of illness was calculated using the Sequential Organ Failure Assessment (SOFA) Score. RESULTS: The HAM-A score in the video group was 5.65 points lower than in the no video group ([ß = -5.65, 95% CI -11.12 -0.18] P = 0.04). The statistically significant difference was maintained when adjusting for patients' SOFA Score and patients' provenance (P = 0.03). CONCLUSION: CPR video used to supplement ICU team-led code status discussions reduced surrogates' anxiety, as compared to no video. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT03630965.

DNA recovery from unfired and fired cartridge cases: A comparison of swabbing, tape lifting, vacuum filtration, and direct PCR.

The ability to recover trace DNA from fired cartridge cases can help establish important leads regarding the handler of the ammunition. Over recent years, several DNA recovery techniques for fired ammunition have been published. Three techniques of significant interest include tape lifting, direct PCR, and vacuum filtration. This study aimed to compare these to the swabbing method currently employed in our jurisdiction. Brass and nickel cartridges of five different calibres were spiked with 20ng of saliva and subject to DNA collection using all four DNA recovery methods. Unfired and fired cartridges were tested to examine the effects of firing. Swabbing recovered a greater quantity of DNA than vacuum filtration while no significant differences were found between swabbing and tape-lifting. The calibre of ammunition had no effect on DNA recovery. Firing significantly reduced DNA yield from nickel cartridges, while unfired brass cartridges returned less DNA than unfired nickel cartridges. PCR inhibition was not observed in any samples, although degradation indices suggested that most samples were slightly or moderately degraded. Analysis of profiles showed that swabbing and tape lifting resulted in greater numbers of alleles from fired nickel and brass cartridges compared to direct PCR. Samples from nickel cartridges were found to have a greater number of uploadable profiles than samples from brass cartridges. In addition, three mixed profiles were obtained from the single source spiked cartridges as well as evidence of pre-existing DNA on uncleaned cartridges and contaminating alleles on cleaned cartridges. Our results suggest that tape-lifting can be a suitable alternative to swabbing, but that caution must be taken when interpreting profiles from fired cartridge cases as small amounts of DNA not associated with the handling of the cartridges may be present.

Forensic Autosomal Short Tandem Repeats and Their Potential Association With Phenotype.

Forensic DNA profiling utilizes autosomal short tandem repeat (STR) markers to establish identity of missing persons, confirm familial relations, and link persons of interest to crime scenes. It is a widely accepted notion that genetic markers used in forensic applications are not predictive of phenotype. At present, there has been no demonstration of forensic STR variants directly causing or predicting disease. Such a demonstration would have many legal and ethical implications. For example, is there a duty to inform a DNA donor if a medical condition is discovered during routine analysis of their sample? In this review, we evaluate the possibility that forensic STRs could provide information beyond mere identity. An extensive search of the literature returned 107 articles associating a forensic STR with a trait. A total of 57 of these studies met our inclusion criteria: a reported link between a STR-inclusive gene and a phenotype and a statistical analysis reporting a p-value less than 0.05. A total of 50 unique traits were associated with the 24 markers included in the 57 studies. TH01 had the greatest number of associations with 27 traits reportedly linked to 40 different genotypes. Five of the articles associated TH01 with schizophrenia. None of the associations found were independently causative or predictive of disease. Regardless, the likelihood of identifying significant associations is increasing as the function of non-coding STRs in gene expression is steadily revealed. It is recommended that regular reviews take place in order to remain aware of future studies that identify a functional role for any forensic STRs.

Retrieving forensic information about the donor through bacterial profiling.

When fingermarks are left on a surface, bacteria originating from the donor's skin are also deposited. The skin microbiome is believed to be extremely diverse between individuals, allowing for potential matching between the bacterial communities and touched objects, known as "bacterial profiling". This study stepped further and investigated how the bacterial profile could be used as an indicator of donor characteristics of potential forensic intelligence interest. Forty-five participants were asked to touch DNA-free playing cards with their dominant and non-dominant hands. Cards were swabbed and bacterial communities determined through 16S rRNA sequencing. Diversity and abundance of bacteria were compared to donor characteristics of gender, age, ethnicity, handedness, home location, sample location, occupation, diet type, use of moisturisers, use of hand sanitisers and use of public transport. Correlations between the bacterial profile with gender, ethnicity, diet type and hand sanitiser use were found. Specifically, the absence of Lactococcus indicated a primarily Chinese diet, while the absence of Alloiococcus indicated female gender, Asian ethnicity and hand sanitiser use. Testing of the prediction models demonstrated highest accuracy for gender estimation, while the prediction of other characteristics showed lower success. This study showed a correlation between the presence of certain bacterial species on donor's hands and personal characteristics of potential forensic relevance, thus demonstrating a novel application of microbiome genotyping in forensic science.

Development of the MitoQ assay as a real-time quantification of mitochondrial DNA in degraded samples.

Mitochondrial DNA is a reliable genetic material for estimating maternally related haplogroups and ancestries. Exploring maternal DNA inheritance is particularly useful when nuclear DNA is degraded or limited, as the copy number of mitochondrial DNA is far greater than the copy number of nuclear DNA. Normal mitochondrial DNA copy number has been estimated to 100 copies per buccal epithelial cell, 4000 copies in skeletal cells and 7000 copies in myocardial cells. This estimation is usually performed via extrapolation from the nuclear DNA quantitation. It is essential to reduce this variability and accurately quantify the exact number of copies of mitochondrial DNA, especially in compromised samples of a forensic or ancient nature. While useful, the testing of mitochondrial DNA is often long and costly and comes with limited success. The accurate quantification of mitochondrial DNA using specific quantitative PCR assays can be used to make better decisions on the downstream testing and success of amplification. As a result, this study develops a real-time assay for the quantification of mitochondrial DNA copy number and assesses its performance on a set of degraded DNA samples. The developed MitoQ assay has been shown to be highly specific to the human mitochondrial genome with no amplification of nuclear pseudogenes being observed and outperformed a previously published concordant assay. Additionally, a high sensitivity was measured to 280 copies of mitochondrial DNA. Minimal variation was observed between each replication cycle, indicating the assay to be robust and repeatable. Overall, this study presents a real-time assay that is sensitive and robust to quantifying mitochondrial DNA copy number in degraded samples. Furthermore, there is potential to incorporate the assay as an additional target in current qPCR assays which use a six-dye chemistry and provide a complete overview of a sample's quality and quantity.

Performance of the Early Access AmpliSeq™ Mitochondrial Panel with degraded DNA samples using the Ion Torrent™ platform.

The Early Access AmpliSeq™ Mitochondrial Panel amplifies whole mitochondrial genomes for phylogenetic and kinship identifications, using Ion Torrent™ technology. There is currently limited information on its performance with degraded DNA, a common occurrence in forensic samples. This study evaluated the performance of the Panel with DNA samples degraded in vitro, to mimic conditions commonly found in forensic investigations. Purified DNA from five individuals was heat-treated at five time points each (125°C for 0, 30, 60, 120, and 240 min; total n = 25). The quality of DNA was assessed via a real-time DNA assay of genomic DNA and prepared for massively parallel sequencing on the Ion Torrent™ platform. Mitochondrial sequences were obtained for all samples and had an amplicon coverage averaging between 66X to 2803X. Most amplicons (157/162) displayed high coverages (452 ± 333X), while reads with less than 100X coverage were recorded in five amplicons only (90 ± 5X). Amplicon coverage was decreased with prolonged heating. At 72% strand balance, reads were well balanced between forward and reverse strands. Using a coverage threshold of ten reads per SNP, complete sequences were recovered in all samples and resolved kinship and, haplogroup relations. Additionally, the HV1 and HV2 regions of the reference and 240-min heat-treated samples (n = 10) were Sanger-sequenced for concordance. Overall, this study demonstrates the efficacy of a novel forensic Panel that recovers high quality mitochondrial sequences from degraded DNA samples.

Laundry in a washing machine as a mediator of secondary and tertiary DNA transfer.

The aim of this work was to investigate the possibility of secondary and tertiary DNA transfer during laundry. The modes of transfer tested were mixed and separate laundry of worn and unworn garments in household and public washing machines. In addition, the possibility of a background DNA carry-over from a washing machine's drum was investigated. In the mixed (worn and unworn garments washed together) laundry experiment, 22% of samples from new unworn socks with no traceable DNA prior to experiment produced DNA profiles post-laundry. In the tertiary DNA transfer experiment performed in a public washing machine (unworn garments only), no detectable DNA profiles were observed. Samples collected from the internal drum of 25 washing and drying machines did not produce detectable STR profiles. The implications of these results are discussed in the context of forensic DNA casework analysis. Graphical Abstract ᅟA real-life scenario of secondary DNA transfer between worn and unworn garments during machine washing has been evaluated. Experiments demonstrated this scenario is possible (22% of samples) and may in fact result in high quality DNA profiles. On the contrary, testing washing machine's interior for deposition of biological material between separate washing cycles to serve as a mediator of tertiary DNA transfer resulted in no DNA profiles.

Investigation of DNA transfer onto clothing during regular daily activities.

Low levels of DNA from an unidentified human source, often referred to as trace DNA, are ubiquitous, can be transferred onto objects by either direct or indirect methods and have an unknown longevity in situ. Clothing items from crime scenes are often submitted for trace DNA analysis, usually in attempt to identify a person of interest. This study examined the transfer of DNA onto three 10 × 10 cm areas located on the front, back and shoulder of an individual's external clothing (n = 300) during a regular day's activity. After wearing for a day, the DNA quantity on all three areas increased approximately 8-fold, which usually corresponded with an increase in the endogenous DNA from the wearer on the front area of the shirt. However, the back area of the shirt was more likely to demonstrate mixtures of endogenous and extraneous DNA. An additional study was also carried out to examine whether domestic laundering is a possible mechanism for the transfer of foreign DNA onto freshly laundered items and revealed that 74% of UV-treated cotton swatch samples produced DNA profiles after laundry with household garments. In summary, this study highlights the ease of DNA transfer onto an individual's external clothing during a regular day, and that extraneous DNA may be already on the clothing item prior to it being worn. The study provides empirical data to assist in the interpretation of trace DNA profiles and support a Bayesian approach to estimate statistical likelihoods for the transfer of foreign DNA. Graphical abstract ᅟ.

Lidocaine-induced methemoglobinemia: a clinical reminder.

Methemoglobinemia is a rare condition in which the iron in hemoglobin is stabilized in the ferric (Fe(3+)) form, making it unable to bind oxygen and leading to tissue hypoxia and possibly death. The condition may be hereditary or acquired, the latter resulting from ingestion or application of common oxidizing agents such as lidocaine. As management of methemoglobinemia depends on prompt recognition, clinicians who administer or prescribe oxidizing agents must be aware of the clinical symptoms of methemoglobinemia, including cyanosis, pulse oximetry values that do not respond to increased oxygen delivery, and altered mental status. Currently, methylene blue is the drug of choice for the management of methemoglobinemia.