Postmortem Interval Research Articles

Development and age estimation of the intrapuparial period of Phormia regina (Diptera: Calliphoridae) for postmortem interval estimation.

Phormia regina (Meigen, 1826; Diptera: Calliphoridae) is a Holarctic species that rapidly colonizes carcasses and has been used as an indicator for determining the minimum postmortem interval. However, studies using morphological methods to estimate the intrapuparial age of P. regina are lacking. In this study, morphological changes within the puparium were observed under a stereomicroscope at 7 constant temperatures ranging from 16 °C to 34 °C. The intrapuparial period was categorized into 12 substages. Morphological indicators, including compound eyes, mouthparts, antennae, thorax, legs, wings, and abdomen, were recorded in detail. The observed morphological changes were divided into 6-10 substages, and the duration of each substage was also recorded in detail. The results of this study provide primary data for using the intrapuparial morphology of P. regina when pupae are collected at a crime scene and estimating the minimum postmortem interval.

A Study of Cadaveric Skin Graft Harvest and Usage: An Observational Prospective Pilot Study.

Background Burn injuries pose a significant global public health challenge, causing substantial morbidity and mortality, particularly in low- and middle-income countries. Timely and effective wound coverage is critical in treating severe burns to prevent infection, reduce pain, and promote healing. Cadaveric skin grafts (allografts) have become essential in treating extensive burn wounds, serving as temporary biological dressings to prepare the wound bed for autografting. This study aims to comprehensively analyze the process of cadaveric skin graft harvest and usage in a tertiary care setting. It seeks to evaluate the procedures, challenges, and outcomes associated with cadaveric skin grafts, contributing to optimizing burn care practices and improving patient outcomes. Methods This observational study was conducted at a tertiary care hospital and burns center with a skin bank, involving 44 cadaveric skin graft harvests and 27 applications between July 1, 2011, and June 30, 2013. The study focused on prospective donors and recipients needing cadaveric skin grafts. Inclusion criteria for donors included consent from the next of kin and the absence of infections or septicemia, while exclusion criteria included prolonged post-mortem intervals and medico-legal cases. The procedures adhered to the Euro Skin Bank protocols, encompassing retrieval, processing, storage, and usage. Data were analyzed using Epi-Info version 7.2.1 software, employing descriptive statistics for categorical variables. Ethical clearance was obtained from the university ethical committee, with mandatory written informed consent for skin donation. Results Out of 519 deaths in the tertiary care hospital, significant barriers to skin donation included septicemia, skin changes, late reporting, young age, medico-legal issues, and positive viral markers. Notably, 114 (21.97%) of next of kin refused consent. Cadaveric skin was harvested in five (11.36%) cases, with potential donors identified in 78 (15.02%) of deaths. Donors were predominantly older males, with efficient procurement processes ensuring timely harvests. The tertiary burns center facilitated 39 (88.63%) cases of cadaveric skin harvests with a skin bank, either at the donor's home or other hospitals notified to the burns center. Cadaveric skin grafts were applied in 27 cases, primarily for burns, with high graft uptake observed over 10 days. Non-healing ulcers showed 100% graft uptake. The survival rate among burn patients was 20 (74%), with deaths mainly due to sepsis and multi-organ failure. Significant barriers to obtaining consent included a lack of awareness, superstitions, social stigmas, and religious objections. Conclusion The study highlights the critical role of cadaveric skin in managing extensive wounds, particularly burns. Despite challenges in obtaining consent and limited donor availability, cadaveric skin grafts effectively prepared wound beds for autografting, contributing to improved patient outcomes. Increasing community awareness and addressing superstitions and social stigmas are essential for improving donation rates.

Unveils key proteins in Xinjiang goat muscle linked to post-mortem meat quality: A TMT-based proteomic analysis

An extensive proteomic analysis utilizing the tandem mass tag (TMT) method was conducted to investigate the changes in protein expression in the longissimus dorsi muscle of Xinjiang goats over various post-mortem intervals: immediately after death within 0 h, 12 h, 24 h and 48 h. The investigation carefully identified around 108 proteins that showed significant changes in expression during these intervals. Among these proteins, six were highlighted for their crucial roles in muscle growth and differentiation of muscle fibers post-mortem. These proteins, namely COL12A1, MRPL46, CTNNB1, MYH1, CAPZA1, and MYL9, have a direct effect on the meat's quality attributes, such as tenderness and color. Further discuss observed a progressive increase in the expression of proteins linked with oxidative metabolism (MSRB2, ENOX1, LOC102170282, GSTM1, and AOC3) as the post-mortem aging period extended, particularly between 24 h to 48 h. These proteins are instrumental in defining the color and flavor profiles of goat meat, underscoring the importance of precise processing and storage conditions to preserve meat quality during the critical aging phase. This enhanced understanding of protein expression dynamics offers significant implications for optimizing meat quality and provides a scientific basis for post-mortem handling practices in the goat meat industry.

Age estimation of Phormia regina pupae based on ATR-FTIR and chemometrics

Accurate postmortem interval estimation is vital in the investigation of homicides, suicides, and accidental deaths. It is key in narrowing suspect lists, improving crime-solving efficiency, and offering solace to bereaved families. The intra-puparial period, comprising about half of a fly’s developmental cycle, presents challenges for morphological age estimation. External changes are limited to color shifts and the appearance of respiratory horns on the puparium only within several hours after pupariation, while detailed internal development analysis often requires invasive methods like removing the puparium, which can be damaging. Additionally, these techniques usually depend on a forensic entomologist’s expertise, which lead to subjective biases. This study employed attenuated total reflection-fourier transform infrared spectroscopy, a rapid, non-destructive method for analyzing proteins, chitosan, and chitin in puparia. Data showed a consistent reduction in the concentration of the amide I band within the puparium during the intra-puparial development at five constant temperatures (19 °C, 22 °C, 25 °C, 28 °C and 31 °C). This trend in the spectral data effectively distinguishes pupae at various stages of intra-puparial development, facilitating precise age estimation, which is critical for the estimation of the minimum postmortem interval (PMImin). Finally, this work combined the total reflection-fourier transform infrared spectroscopy with chemometric analysis and successfully developed a partial least squares discriminant analysis model and a random forest model, with accuracies of 88 % and 81 %, respectively. These models enable the non-invasive age estimation of P. regina in its intra-puparial period, a stage traditionally difficult to assess morphologically, thus laying the groundwork for PMImin estimation using fly pupae.

Impact of ante-mortem fluoxetine administration on estimation of post-mortem interval and insect activity in rabbit carcasses

BackgroundIncreasing the number of drug-related deaths has affected medico-legal death investigations. Drugs within a corpse have a great impact on the insects’ development rate which in turn will affect the rate of post-mortem decomposition and the estimation of the post-mortem interval. This explains the importance of the application of forensic entomotoxicology, which studies the impact of drugs and toxins on the development and succession patterns of insects. The current study aimed to determine the impact of fluoxetine, one of the selective serotonin reuptake inhibitors (SSRIs), on post-mortem decomposition, insects’ attraction, and its pattern of succession on carcasses. Sixteen healthy male and female Oryctolagus cuniculus rabbits were chosen to be included in this study. They were divided into a treated group of eight rabbits received oral fluoxetine for 28 days and a control group of eight rabbits received oral distilled water for 28 days. After oral administration of 10 mg/kg/day of fluoxetine and distilled water for 28 days, rabbits were sacrificed, and carcasses were transmitted to the roof of Research and Training Centre on Vectors of Diseases at faculty of Sciences, Ain Shams University, for following up the post-mortem decomposition process and insect’s attraction to carcasses for 60 days. Carcasses were put in two outdoor sites that differ in temperature to assess the effect of temperature on decomposition process.ResultsFluoxetine administration has accelerated the rate of post-mortem decomposition in the treated carcasses by 3–9 days compared to the control ones and affected the numbers and species of attracted insects, while it had no effect on the insects’ succession patterns. Exposure of carcasses to direct sunlight has accelerated the rate of decomposition in comparison to that of carcasses put in shade in the overall period of decomposition by about 14 to 16 days.ConclusionsFluoxetine has an important and effective role in post-mortem decomposition and estimation of post-mortem interval (PMI) and has a great impact on attracted insects to the treated carcasses. Temperature has a great effect on the rate of decomposition of carcasses. Higher temperature accelerates the rate of post-mortem decomposition.

A review of the estimation of postmortem interval using forensic entomology.

The postmortem interval (PMI) is a crucial factor in death investigations. For PMIs exceeding 24 h the forensic pathologist must turn to other specialties that focus on decompositional ecology of animals, including humans. Primary among these specialties is forensic entomology. Here, we review the importance of forensic entomology in estimating the PMI, and we examine the factors that influence these estimates. Among key concerns are environmental factors, especially temperature, and aspects of insect biology. Additionally, we examine current methods used for calculating PMI based on insects and their development.

Changes in heart dimensions in decomposition using porcine and ovine animal models: a method for estimating decomposed human heart weight

ABSTRACT Heart weight is a routine measurement at post-mortem examination. An increased heart weight is associated with pre-existing heart disease and sudden cardiac death. However, during decomposition, the heart weight measured at post-mortem examination may not reflect the weight at the time of death. A previous study showed that heart dimensions can be used to estimate heart weight. This study documents the changes in heart dimensions during decomposition using porcine and ovine animal models. It shows that, in contrast to heart weight, which decreases in the post-mortem interval, the heart dimensions increase. Heart width increases and subsequently plateaus at the end of the 18 days to a mean of 6 and 8 mm in ovine and porcine hearts, whereas the length continues to increase. Using the results of this study, in conjunction with previous published literature, the heart width may be used as a parameter to estimate heart weight and determine cardiac hypertrophy at the time of death in decomposed hearts.

Morphometric Characteristics of Postmortem Changes in the Brain of Newborns Depending on the Duration of the Postmortem Period.

The morphometric characteristics of brain tissue were studied based on autopsy material from 49 deceased newborns divided into 7 groups based on the time after death. Samples were taken from the upper (frontal lobe) and lower (occipital lobe) regions relative to the supine position of the body. Paraffin sections were prepared from these samples and stained with hematoxylin and eosin. Histological preparations were analyzed using an image analysis system to determine the area of gliocyte nuclei, cross-cut blood vessels, and expanded area around them in the white matter of the brain. Based on these data, severity indices were calculated for both cellular (pericellular) and vascular (perivascular) expansion. The dynamics of changes in morphometric parameters within the range of cellular and vascular alterations on brain tissue specimens, which reflect the development of postmortem hypostasis and autolysis in this organ, can be used to estimate the duration of the postmortem interval. At the same time, these changes, when combined with other non-specific postmortem findings, should be distinguished from long-term pathological processes and diseases that may have occurred during life.

Post-mortem utility of Neuron Specific Enolase (NSE) and Calcium Binding Protein B (S100B) for differentiating traumatic brain injury from other causes of death.

In forensic pathology, identifying causes of death in traumatic brain injuries (TBIs) devoid of observable signs presents a significant challenge. Post-mortem biochemistry plays a crucial role in forensic medicine, particularly in determining causes of death in TBIs that lack macroscopic or histopathological evidence. This study aimed to evaluate the utility of Neuron Specific Enolase (NSE) and S100 Calcium Binding Protein B (S100B) in post-mortem serum and cerebrospinal fluid (CSF) as markers for TBI. The relationship of these biochemical markers with survival time and post-mortem interval was also studied. The study sample consisted of 63 cases each from the TBI and the Non-TBI (NTBI) group. The NTBI group comprised of deaths due to mechanical asphyxia, myocardial infarction and isolated trunk trauma. While serum S100B and CSF NSE emerged as a promising marker for TBI, CSF S100B failed to differentiate TBI from the other causes of death. The absence of an association between the level of markers and survival time or post-mortem interval in TBIs highlights the limitations of these biomarkers in such contexts. This study underscores the potential of biochemical markers like serum S100B and CSF NSE in identifying TBI deaths, aiding forensic diagnoses where there are evidentiary limitations in traditional methods. Further research exploring additional markers and body fluids could enhance diagnostic precision in forensic neuropathology.

Development of mixed linear models to analyze and describe the impact of malathion on the larval growth of Megaselia scalaris (Diptera: Phoridae) under various feeding media and environmental conditions.

Forensic entomology plays a crucial role in estimating the minimum postmortem interval through the study of insect larvae found at crime scenes. The precision of this estimation relies on various biotic and abiotic elements that simultaneously influence insect growth and development, encompassing factors such as temperature, humidity, photoperiod, diet, and the existence of xenobiotics in decomposing tissues. Despite numerous studies on the influence of these factors, including the impact of xenobiotics, there are currently no robust tools available for making corrections to this estimation considering concurrently all variables. In an attempt to propose an exploratory and descriptive statistical model to analyze the simultaneous effect and interaction of different variables on larval growth, this study aimed to compare the effect of malathion on the growth of Megaselia scalaris (Loew, 1866) (Diptera: Phoridae) raised in malathion-spiked porcine muscle, under controlled and uncontrolled temperature and humidity conditions (environmental conditions). Larvae were also reared using various growth media. A split-plot design that combined crossed and nested factors was employed; 2 linear mixed models were developed to assess the relationships between the variables. The model provides valuable insights into the complex interactions among xenobiotics, growth media, and environmental conditions in the size and development of M. scalaris.

Forensic entomology in homicide cases: study of a corpse found inside a buried vehicle.

Forensic entomology plays a crucial role in death investigations, particularly in estimating the postmortem interval (PMI). This study presents a forensic entomology case involving a corpse found in a buried utility vehicle. The victim was in an advanced state of decomposition, with autopsy findings revealing gunshot wounds. Cadaveric fauna was collected at the scene and during the autopsy. The analysis revealed a diverse insect community, with predominance of Compsomyiops fulvicrura and Piophila casei. The time of development of species like Dermestes maculatus and Necrobia rufipes was used to estimate the minimum PMI. The presence and low abundance of Calliphora vicina, a species preferring lower temperatures, shed light on the seasonal conditions at the time of death and suggested possible body concealment shortly after death. This research is the first to report insects as evidence in a corpse found in a buried vehicle and contributes to the body of knowledge in forensic entomology. The study also suggests that the use of entomological evidence can provide additional information about the season in which the body was concealed, making it a valuable tool in death investigation and crime scene reconstruction. Finally, it emphasizes the need for proper sampling, expert identification, and close collaboration between forensic entomologists and pathologists.

A nondestructive technique for the sex identification of third instar Cochliomyia macellaria larvae.

Forensic entomology plays an important role in medicolegal investigations by using insects, primarily flies, to estimate the time of colonization. This estimation relies on the development of the flies found at the (death) scene and can be affected (and sometimes corrected) by external factors, such as temperature and humidity, and internal factors, such as species and sex. This study leverages infrared (IR) spectroscopy combined with machine learning models-Partial Least Squares Discriminant Analysis (PLS-DA) and eXtreme Gradient Boosting trees Discriminant Analysis (XGBDA)-to differentiate between male and female Cochliomyia macellaria larvae, commonly found on human remains. Significant vibrational differences were detected in the infrared spectra of third instar C. macellaria larvae, with distinct peaks showing variations in relative absorbance between sexes, suggesting differences in biochemical compositions such as cuticular proteins and lipids. The application of PLS-DA and XGBDA yielded high classification accuracies of about 94% and 96%, respectively, with female spectra consistently having higher sensitivity than males. This non-destructive approach offers the potential to refine supplemental post-mortem interval estimations significantly, enhancing the accuracy of forensic analyses.

Microscopic characteristics of peri- and postmortem fracture surfaces

This study investigated if microscopic surface features captured with a scanning electron microscope (SEM) effectively discriminate fracture timing. We hypothesized that microscopic fracture characteristics, including delamination, osteon pullout, and microcracks, may vary as bone elasticity decreases, elucidating perimortem and postmortem events more reliably than macroscopic analyses. Thirty-seven unembalmed, defleshed human femoral shafts from males (n=18) and females (n=2) aged 33–81 years were fractured at experimentally simulated postmortem intervals (PMIs) ranging from 1 to 60 warm weather days (250–40,600 ADH). A gravity convection oven was used to approximate tissue decomposition at 37 C and 27 C, and the resulting heat-time unit (accumulated degree hours, or ADH) was used to examine fractures in elastic/wet versus brittle/dry bone. The bones were fractured with a drop test frame using a three-point bending setup, sensors were used to calculate fracture energy, and high-speed photography documented fracture events. The following data were collected to relate fracture appearance to the biomechanical properties of bone: PMI (postmortem interval) length in ADH, temperature, humidity, collagen percentage, water loss, bone mineral density, cortical bone thickness, fracture energy, age, sex, cause of death, and microscopic fracture feature scores. SEM micrographs were collected from the primary tension zones of each fracture surface, and three microscopic fracture characteristics were scored from a region of interest in the center of the tension zone: percentage of delaminated osteons, percent osteon pullout, and number of microcracks. Multiple linear regression showed that microscopic fracture surface features are strong predictors of ADH (adjusted R-squared=0.67 for the 0 – 40,000 ADH samples; adjusted R-squared=0.92 for the 0–16,000 ADH samples). Osteon pullout is the single best predictor of ADH. Additionally, water loss is the primary driver of bone elasticity changes in low ADH samples, while collagen fibers appear to remain intact until later in the postmortem interval (approximately 40,000 ADH in this study). The results of this study indicate microscopic fracture surface analysis detects the biomechanical effects of decreased elasticity more reliably and with greater sensitivity than macroscopic analysis.

Quantifying canine tissue stiffness change patterns using shear-wave elastography: implications for time of death estimation

ABSTRACT This study investigates the applicability and reproducibility of shear-wave elastography (SWE) in detecting changes in tissue stiffness of canine carcasses. SWE was performed on six canines by two operators. The target organs were liver, spleen, kidney, and thigh muscles. SWE was performed ante-mortem and up to 48-hours post-mortem at specific intervals. The Mann-Whitney U-test and Spearman correlation coefficient showed insignificant correlation between gender and weight with shear-wave velocity (SWV) in ante-mortem scans. The Kruskal-Wallis H-test showed significant differences in SWV for all organs. Intraclass correlation coefficient (ICC) showed excellent correlation for all target organs except for kidneys. Pairwise comparison showed a similar SWV trend for abdominal organs. Accuracy metrics were calculated for determining the post-mortem interval using SWV values. The liver had the highest accuracy (0.69–0.83) across different post-mortem interval thresholds within the cut-off values of ≥2.0 m/s, 1.8–2.0 m/s, <1.8 m/s indicating ≤6 hours post-mortem, 12–18 hours post-mortem and >18 hours post-mortem. The spleen, kidney and thigh muscle demonstrated moderate-to-poor accuracy within the same cut-off parameters. Post-mortem SWV changes in canine solid organs, and soft tissues, particularly the liver, demonstrate a reproducible pattern, which may have value in determining the post-mortem interval.

Artificial Intelligence in Forensic Sciences: A Systematic Review of Past and Current Applications and Future Perspectives.

The aim of this study is to review the available knowledge concerning the use of artificial Intelligence (AI) in general in different areas of Forensic Sciences from human identification to postmortem interval estimation and the estimation of different causes of death. This paper aims to emphasize the different uses of AI, especially in Forensic Medicine, and elucidate its technical part. This will be achieved through an explanation of different technologies that have been so far employed and through new ideas that may contribute as a first step to the adoption of new practices and to the development of new technologies. A systematic literature search was performed in accordance with the Preferred Reported Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in the PubMed Database and Cochrane Central Library. Neither time nor regional constrictions were adopted, and all the included papers were written in English. Terms used were MACHINE AND LEARNING AND FORENSIC AND PATHOLOGY and ARTIFICIAL AND INTELIGENCEAND FORENSIC AND PATHOLOGY. Quality control was performed using the Joanna Briggs Institute critical appraisal tools. A search of 224 articleswas performed. Seven more articles were extracted from the references of the initial selection. After excluding all non-relevant articles, the remaining 45 articles were thoroughly reviewed through the whole text. A final number of 33 papers were identified as relevant to the subject, in accordance with the criteria previously established. It must be clear that AI is not meant to replace forensic experts but to assist them in their everyday work life.

The polychromatism of postmortem cerebrospinal fluid.

Based on the assumption that postmortem cerebrospinal fluid (CSF) is contaminated depending on the chosen sampling technique in the forensic setting resulting in bloody or at least hemolytic CSF samples, we systematically documented a total of 183 postmortem CSF samples. These samples were all assessed for their quality and color, regardless of the cause of death or the postmortem interval. The investigations were carried out through subjective assessment of color and turbidity, as well as objective measurements of the optical density (OD) of the CSF supernatants after centrifugation of each sample, with standardized photographic documentation. The observations revealed that in 28 cases the CSF was absolutely (crystal-) clear and transparent. Most of our samples showed color changes ranging from xanthrochromic to rose. Intensive staining of the supernatants was only found in a small proportion of the examined collective. We found that postmortem CSF has no uniform appearance but rather a diverse range of color spectra, and the color, as well as the OD of the CSF, correlates significantly with the postmortem interval (p < 0.001) when sampled using the proposed standard procedure.

Post-mortem Interval estimate based on dental pulp: A histomorphology approach.

Estimating the post-mortem interval (PMI) of human remains based on the histomorphology of dental pulp parameters is promising, but available evidence is scarce and sometimes contradictory without a scientific model. The aim of the study is to characterise the histomorphological changes of dental pulp associated with the decomposition of human remains by a qualitative and quantitative approach. The main aim is to establish a correlation based on post-mortem (PM) dental pulp histomorphology and the PMI, and whether pulp degradation could be an available medico-legal tool for PMI estimation beyond the first week after death (late PMI). The eligible sample consisted of 27 sound teeth from 16 healthy patients aged 16 to 72 years due to orthodontic or oral surgery treatment, to create PMI's simulating the death of the subject as the time elapsed from tooth avulsion. Data collected from patients (sex, date of birth, tooth position, date and hour of the avulsion, date and hour of pulp extraction) were anonymised in accordance with the requirements of Faculty of Dental Medicine of the University of Lisbon. The sample was divided into 9 groups of 3 teeth according to different PMI sets from T0 (baseline) up to 2 weeks (T0, 7, 12, 24, 36, 48, and 72 hours, 1 and 2 weeks). All the dental samples were stored at room temperature up to the time of pulp extraction and then prepared with haematoxylin and eosin stain. High-resolution microscopy was performed to obtain histological images. An operator performed the qualitative evaluation of blood vessels, collagen fibres, and the extra-cellular matrix (ECM) in PM pulps and measured the variation in cells/nuclei density by counting 6 different ROIs (Regions of Interest) for each pulp manually and automatically (quantitative analysis). Qualitative results showed that the degeneration of dental pulp appears 7 hours after death but histological changes in vessels, fibres, and ECM in PM dental pulp are characterised by high variability, consequently it is not possible to generalise the results for early PMIs. Quantitative measurements proved that cell count cannot be standardised due to the presence of superimposed layers of cells and nuclei fragmentation. Odontoblasts did not demonstrate evidence of cellular or nuclear lysis up to 14 PM suggesting their applicability in late PMIs. Future research will focus on late PMIs and different techniques of tooth preparation.

MiR-122, miR-133a, and miR-206 as potential biomarkers for post-mortem interval estimation.

Accurate estimation of post-mortem interval (PMI) is crucial in forensic investigations. MicroRNAs (miRNAs or miRs) are small non-coding RNAs that remain relatively stable within the cell nucleus despite post-mortem changes. We assessed three target genes (miR-122, miR-133a, and miR-206) for PMI estimation using 72 healthy adult male BALB/c mice exposed to two different temperatures (4 and 21℃) at nine different time points over 10days. Initially, the stability of the two reference genes (RNU6B and 5 srRNA) was evaluated using gene stability analysis tools (Delta Ct, Best Keeper, and Genorm) to select the optimal reference gene. RNU6B was found to be the most stable endogenous control. Subsequently, the expression patterns of miR-122, miR-133a, and miR-206 were analyzed within a 10-day PMI period using the heart, skeletal muscle, liver, and brain tissues. At 4℃, miR-122 levels significantly decreased on days 8 and 10 in all tissues, with only the liver showing significant changes at 21℃. MiR-133a decreased over time in the heart, muscles, and brain, showing a dramatic decrease on days 8 and 10 in the heart and muscles at both temperatures. Although miR-206 levels decreased over time in muscles and liver at 4℃, these increased in the brain at 21℃, with no expression changes in other organs. In summary, miR-122, miR-133a, and miR-206 are potential PMI markers in heart and skeletal muscle tissues.

The Influence of Substrates on Blow Fly (Diptera: Calliphoridae) Development

Blow flies (Diptera: Calliphoridae) can be used in forensic entomology to provide information, including an estimate of the time of colonization and minimum postmortem interval, based on insect development. This study examined the development of third instar Calliphora terraenovae Macquart in four substrates: pine shavings, soil, sand, and clay. Pupation time, survival to adult, and wing vein length were measured to examine the substrate influence. There was a significant difference in the time to pupation (F3,36 = 11.87, p &lt; 0.0001) and the number of flies that eclosed (F3,36 = 4.716, p = 0.007) among the substrates. Blow flies pupated faster in pine shavings and eclosed as adult flies faster in sand than in other substrates. Adults eclosed in the sand in 21.9 days, followed by pine shavings (22.8), clay (24.2), and soil (26.6). Although overall survivorship was low (10–46%), the greatest number of flies eclosed in sand, and the fewest in clay. Understanding the factors that impact blow fly development can help forensic entomologists improve rearing protocols and apply this information to death investigations, especially in cases with buried remains.

An experimental study to estimate the early postmortem interval based on the degradation of lncRNAs in rat brain tissue

To study the degradation of lncRNAs in EPMI in rat brain tissue, this study provides a new direction for the estimation of EPMI. LncRNA high-throughput sequencing was performed on the brain tissues of hemorrhagic shock model rats at 0 h and 24 h, and the target lncRNAs were screened. Samples at 0, 1, 3, 6, 12, 18 and 24 h after death were collected, and miRNA-9 and miRNA-125b were used as reference genes. The relative expression levels of lncRNAs at each PMI were detected by RT–qPCR, and a functional model involving lncRNAs and EPMI was established. Samples were collected at 6, 9, 15, and 21 h after death for functional model verification. The expression of several lncRNAs decreased with the prolongation of EPMI, and the mathematical model established by several lncRNA indices exhibited good fit. The verification results of the multi-index joint function model are significantly better than those of the single-index function model, and the established model is more practical. There is a linear relationship between lncRNAs and EPMI, and the multi-index function model is significantly better than the single-index function model, which is important for EPMI inference in forensic pathology practice.