Discrimination of slight thermal damage to hair for arson investigation.

To determine whether a suspect was in close contact with the fire source at a fire site through slight thermal damage to hair, a cone calorimeter was employed to simulate fire scene conditions as a standard radiant source. The research focused on analyzing the thermal behavior of black hair and delving into the morphological characteristics of hair exhibiting slight thermal damage. At temperatures exceeding 240 °C, the proteins within the hair began to degrade. This degradation, in conjunction with tension along the hair shaft resulting from water loss, led to the formation of microcracks that could be detected through scanning electron microscopy (SEM) but eluded observation with an optical microscope (OM). It is noteworthy that the initial slight thermal damage was regularly located at the hair shaft but not the hair tip, which should be the key parts when exanimating hairs without obvious thermal damage. Additionally, during very short exposure, the appearance of typical slight thermal damage on fire is probabilistic events. Along with the increase of temperature, the organic compounds in hair were thermally degraded into NH3, SCO and carbon CO2, resulting in the typical traces of discoloration, expansion, blistering, and cracking presented at hair shafts and tips. The probability of encountering both slight and obvious thermal damage on hair increased with rising temperatures. By observing the traces on the easily overlooked part of the hair shaft, the research established a method to analyze and discriminate the slight thermal damage to hair at fire scene, which provide valuable references for confirming arson suspects.

Research on species categorical authentication of accelerants based on flame characteristics analysis.

Species categorical authentication of accelerants has traditionally relied on fire debris analysis. To explore a novel method for identifying the accelerants species, four commonly used accelerants for arson were loaded onto different substrates and ignited at different locations. The entire combustion process was recorded and flame characteristics were analyzed. The results showed that the probability density function (PDF) of flame apex angle counts within a certain period after ignition can be used to distinguish accelerant species, and this method is not affected by accelerant loading amount, ignition location, and substrate, demonstrating strong stability and universality, while the temporal variation of flame area and the value obtained by dividing half of the flame width by the flame height (tangent of flame cone angle) can effectively differentiate gasoline and diesel. The utilization of flame characteristics for identifying accelerants species holds significant implications for arson investigation.

Study on the methods of visualizing bloodstains after thermal exposure.

To establish the correlation between thermal conditions imposed on bloodstains and visualizing effect of enhancement techniques, infrared photography and four chemical enhancement reagents were used to visualize bloodstains following thermal exposure. A black tile was selected as the substrate to intensify the visualization challenge, with a Cone Calorimeter serving as the standardized heating source to control thermal conditions. Compared with standard photography, infrared photography is proven to be a valuable complement to chemical reagents, showing significant advantages in visualizing bloodstains after thermal exposure. However, it is worth noting that infrared image fell short of standard image when bloodstains displayed raised, embossed morphology or when bloodstains almost disappeared under specific conditions. The enhancement effectiveness was found to be strongly correlated with thermal conditions imposed on bloodstains, and the morphology evolution of bloodstains during heating affected the chemical enhancement effect additionally, especially when the bulge morphology was formed, and it was observed that reagents were more effective after removing the dense shell of the bulge. Among the four selected chemical enhancement reagents, fluorescein performed exceptionally well, maintaining its effectiveness even for bloodstains heated at 641°C for 10 min. TMB demonstrated its visualizing ability for bloodstains heated at 396°C for 5 min and heated at 310°C for 20 min. BLUESTAR® followed afterwards, while luminol performed worst. The correlation between thermal conditions imposed on bloodstains and the corresponding visualizing effectiveness of enhancement techniques provides important references for detecting bloodstains at fire scenes.

Identification of the potential roles of ring finger protein 8 in TP53-mutant breast cancer.

Breast cancer is one of the malignant tumors with the highest mortality rate. With the development of precise treatment technology for cancer, numerous molecular targets have been identified and applied in the treatment of diseases. The present study investigated the potential role of ring finger protein 8 (RNF8) in TP53-mutant breast cancer and explored its possible mechanisms of action through a combination of bioinformatics techniques and cell biology. The results revealed that significantly different genes were expressed in RNF8-knockout mice sequencing data compared with in the control group in the presence of TP53 mutations. Downregulated genes were significantly enriched in several pathways of cell proliferation and apoptosis regulation, development and transcription regulation, while upregulated genes were mainly enriched in immune response-associated signaling pathways. Therefore, the consensus genes of the major signaling pathways were further analyzed, revealing that among patients with TP53 wild-type breast cancer, the prognosis of patients with low expression levels of fibroblast growth factor receptor 1, LIM homeobox 2 and EPH receptor B2 was improved compared with that of patients with high expression levels, while among patients with TP53-mutant breast cancer, there was no significant difference in survival status. In addition, among patients with TP53-mutant breast cancer, the prognosis of patients with high BR serine/threonine kinase 1 expression was significantly improved compared with that in patients with low expression. Finally, cell biology experiments demonstrated that in TP53-mutant breast cancer cells (HCC1937), inhibition of RNF8 significantly inhibited the proliferation of TP53-mutant HCC1937 cells and promoted their apoptosis. The present findings may enrich the understanding of the role of RNF8 and indicated that RNF8 may be used as a potential molecular target in TP53-mutant breast cancer, which may lead to the development of clinical treatment strategies.