Objective and accurate forensic genetic analysis results are the basis for making accurate identification opinions. With the increasing sensitivity of testing equipment and amplification kits, the pressure to prevent laboratory pollution is increasing. Among them, the contamination of PCR amplification products is the most difficult type of pollution to prevent. This research introduces an anti-pollution amplification kit, which contains 16 short tandem repeats (STR) locus, one sex identification locus (Amel) and one Y chromosome insertion deletion locus (Indel). Anti-pollution amplification kit can obtain DNA fragment containing uracil base through STR multiplex amplification, and this type of DNA fragment can be efficiently hydrolyzed by uracil DNA glycosylase (UDG enzyme) at 50℃. An additional 50℃ incubation before each new round of PCR amplification can completely eliminate the pollution threat of previous amplification products to the results. After testing, the anti-pollution amplification kit has excellent anti-pollution ability, and uracil base does not change the DNA typing results. Its detection sensitivity does not decrease; the stability of DNA product fragments does not decrease; and subsequent electrophoresis analysis is not affected. This reagent kit can effectively eliminate contamination of amplification products.

Due to the influence of photograph-taking conditions including distance, competence of monitoring equipment and blurring from the moving objects, the relevant video images are frequently rendered into poor visual quality, making them difficult to either recognize or meet the investigative requirements for public security. Therefore, a super-resolution reconstruction is here proposed about video image based on binocular parallax mechanism. Particularly, with the camera fixed at a position, the tested moving object is to have its continuous motion kept into images of different parallax against which two time-different frames of the object's picture are placed as binocular images into the adopted network model. The image is extracted of its multi-scale information with the feature extraction module outfitting improved atrous spatial pyramid pooling, followed to have its effective information obtained through introduction into the parallax attention module and successively its super-resolution right/left image (frame) reconstructed via the residual network. Finally, the deconvolution is operated to visualize the convolution process. The experimental results show that the output image, compared with the resultant from traditional video image super-resolution reconstruction, has increased its peak's signal-to-noise ratio by 1.27 db, enhanced its structural similarity index by 0.004, with its subjective visual effect being obviously clear and its edge blur reduced, hence demonstrating that the excellence is present of the here-adopted video image super-resolution reconstruction based on binocular parallax mechanism. A new idea is thus provided for improving video image's resolution with such a manipulation of replacing binocular images with two frames taken at similar-yet-different time points in a video and combination of the convolutional neural networks for super-resolution. The approach adopted here can also be applied to recover low-resolution video images exampled as those handled in this article about recognition of one person's portrait and a car's registration plate. Certainly, the method proposed here uses only two frames of video images, and its feature extraction of image has some limitations, too. Accordingly, the next and/or future work may consider into taking multi-frame images of one moving object at different time points and improving the performance with image feature extraction.

In video investigation, the crime-related video color deviation will incur the relevant visual algorithm to reduce its robustness and lead to artificial cognitive bias. However, most present algorithms handling color constancy are poor of both illumination estimation accuracy and real-time performance for color cast correction, hence leaving them being difficult to apply into processing videos involved with crimes. To address the above problems, an algorithm is here proposed for downsampling white patches to inhibit the local over-exposed pixels so that the color cast correction can be carried out into a single image or one video frame. For avoiding interference to illumination estimation of the over-exposed pixels in video frames and/or images, those over-exposed pixels are to determine their componential values on the respective pixel channel so as to have a mask coverage be subsequently carried out. The video frames and/or images are afterwards to downsample through selecting pixels randomly. Finally, the white patch algorithm is to apply into weakening the influence of disturbing dots and/or stray noises on illumination estimation, meanwhile reducing the amount of data and speeding up the algorithmic operation. For the dataset of either the standard or the self-built, the built algorithm can deliver better color cast correction in the video frames and images collected from multiple devices, running at the respective 0.03 s and 0.02 s in the two datasets, demonstrating an obviously quicker speed than that from most algorithms of color constancy. The algorithm proposed here is able to quickly perform illumination estimation and color correction in the video frames or images collected from multiple devices, having advantages of high-precision illumination estimation and evident speed. It can be used as a correction strategy for one crime-related color-cast video and a single image.

The Optically Variable Ink (OVI) can change its color from one to another at different angles observed onto the RMB's 5th-edition banknotes, e.g., the 100-denomination one. Here, micro confocal Raman spectroscopy was trial to identify the mimic-OVI ink of counterfeit 100-denomination RMB notes. With 77 edition-various counterfeit 100-denomination RMB notes seized from different dens, the optimal test condition was set up so that the Raman spectra were collected from the seized counterfeit notes, followed to have them undergone into serial preprocessing of wavelet-transform denoising and realization, asymmetric least-square baseline deduction and spectral normalization. Such the above tackling measures extorted every tested counterfeit note to deliver its eigenvalues from whole Raman spectra of OVI. Consequently, Raman shift peak was found to correlate with the ingredients of pigment, thus having the counterfeit-note mimic-OVI divided into three sorts: the one containing copper (II) phthalocyanine pigment; the one including both the copper (II) phthalocyanine pigment and polychlorinated copper phthalocyanine pigment; and the one having no Raman shift. The different paper used with counterfeit note was able to make Raman shifts and fluorescent backgrounds further diverse, hence having additional five classifications brought into the sort 1 counterfeit notes. Accordingly, micro confocal Raman spectroscopy could be a potential tool not only for identification of counterfeit RMB notes based on the different Raman shifts but also for recognition of discrepant counterfeiting means according to dissimilar Raman shifts and intensities, therefore capable of providing basis to track the source/den of counterfeiting note.

A survey was here carried out about high-falling cases so that the influential factors were able to explore on the time spent with the cases' scenes, purposing to provide a theoretical and practical basis for rapid investigation into the scenes of involving cases. The high-falling cases that occurred in the selected district from June 1st, 2014 to May 31th, 2018, were collected and analyzed statistically. In total, 318 pieces of such cases were reviewed, having them kept into groups with the victims' gender and age, locations where cases happened, heights of high-falling, time spent on scene investigation of each case. Statistical analysis was respectively tested with Student t and Chi sqare about the distribution of time spent on the investigation from cases of every group mentioned above, putting the received two test results into comparison. Subsequently, the regression equation published in earlier literature was verified into the cases to estimate the falling height based on the facture degree of skull and extremity bones. Concerning the surveyed cases, suicide was the most common type, acconting for 89.0%, and occurred most in residential area. A mass of scenes were spent within 60 minutes on their investigation, acconting for 78.8% of all the cases. There were older victims in residential and hospital areas than work and other places although no significant difference was correlated with the age of victims who took off from different floors. The lower falling heights were shown at work-related sites than the rest. More time usually took on inspecting those high-falling cases at areas related to work or high floors (10 storeys and above). No significant difference was found of the spent time relating to victims' gender or cases' genre/kind. The verified regression equation performed its effective accuracy up to 75% as it had been applied into 12 practical cases. Accordingly, the falling height would be estimated more accurately if helping hands, e.g., the here-adopted regression equation, can be relied to link the corpse damage with falling height. Consequently, the time spent on scene investigation of high-falling cases will be reduced potently even on the cases occurring to high floor, hence bringing the rapid investigation into success.

During forensic postmortem examination and autopsy, various hazards are potentially subsistent, leaving examiners at the harmfulness from cadavers and their resulting niches, for example, the infectious pathogens, aerosols, blood stains and anatomy tools used for examination and autopsy. Thus, infections or injuries may be very likely to fall over the examiners. Against such the harmfulness and potential dangers, occupational protection should be strengthened to safeguard the examiners. Based on the previous researches of occupational protection equipment, a new concept was here proposed about the definition of forensic autopsy quarantine (FAQ) along with its realization approach. Consequently, a safety box of sharp tools for forensic autopsy was designed and manufactured, capable of having effectively protected the examiners from wounds/injuries caused by e.g., the scalpels. Evidently, the safety box verified the efficacy of FAQ. Therefore, FAQ can be sufficiently and reliably providing not only guidance for the quarantine of various hazard factors occurred during postmortem examination and autopsy but also a significant technical and practical reference for forensic occupational protection.

3D-reconstructed relocation of spectral feature is a key technology in multi-spectral imaging fusion and 3D reconstruction. Here, the feasibility was to explore about relocating spectral data onto 3D-reconstructed dense point cloud through a new neural network HF-Net, one deep-learning-based AI technology and also a hierarchical localization approach based on a monolithic CNN that is able to simultaneously predict local features and global descriptors for spectral localization. Such an HF-Net was adopted to carry out the spectral relocation of heterogeneous localization. Specifically, the MobileNet and NetVLAD layers were taken to extract the global descriptors among the dataset of three-dimensional color point cloud from the spectral image so as to find the approximate position of spectral image in the three-dimensional point cloud. With the conjectural locations obtained through the prior global retrieval within those candidate places, the SuperPoint was utilized to get the local descriptors and key point scores of the spectral image so that the matching spectral points were found in the three-dimensional point cloud, therewith having mapped out the spectral information and three-dimensional reconstruction pattern. By leveraging the learned descriptors, this assay achieved remarkable localization robustness across large variations of appearance, demonstrating more robust and efficient than SSD algorithm. Due to limits with GPU (graphics processing unit) memory, the extracted spectral features were down-sampled from image to the largest resolution of 6016 × 4512 pixels. With HF-Net being trained through multi-task distillation in TensorFlow 1.12, a spectral image had been able to relocate into 3D reconstruction pattern in 12s under having run on the device of NVidia TESLA V100 with 32G memory and CPU of Intel (R) Xeon (R) Silver 4114 with 12G memory. The approach proposed here can realize the fine positioning of 3D spatial information and spectral features of 3D physical evidence. At present, there seems no such an exploration in forensic science home and abroad, revealing that the exploration tried here is a new application of artificial intelligence to the full-dimensional imaging data fusion technology of physical evidence. Such an HF-Net-based relocation is accurate, scalable, efficient, and a monolithic deep neural network choice for descriptor extraction, capable of achieving higher exactness on large-scale multi-spectral imaging fusion and 3D reconstruction.

An intraperitoneal infection model was here established about methcathinone with rat as the experimental animal, and the distribution of both the drug itself and its metabolites was observed in the rat tissues. SD rats, the selected experimental animal, were divided into three groups that were injected of methcathinone via the intraperitoneal route under the respective dose of 7.6 mg/kg, 15.2 mg/kg and 22.8 mg/kg and successively monitored of their poisoning symptoms. The rats were put to death at 5 min, 15 min and 30 min after drug injection, with their heart, liver, spleen, lung, kidney, brain, stomach, muscle, testicle and heart blood being collected immediately. From the extractions of the above rat tissues, HPLC-MS/MS was to detect the distributed methcathinone and its metabolites: cathinone, ephedrine and pseudoephedrine. Few effects were found of dose on distribution patterns of methcathinone, cathinone, ephedrine and pseudoephedrine among the rat tissues. Kidney was shown of highest concentration for the four tested chemical substances. Within same tissue, methcathinone was always demonstrating highest concentration, leaving cathinone, ephedrine and pseudoephedrine being as the sequential followers. Both methcathinone and cathinone were exceeded over the limit of quantification with the tested blood at each dose, contrasting to ephedrine and pseudoephedrine being under the detection limit any time. The distributed methcathinone was sequentially concentrated as 15 min> 5 min> 30 min, the three time points for rat execution. Nevertheless, cathinone was shown concentrated at the order of 30 min> 15 min> 5 min. Ephedrine and pseudoephedrine were found of mainly distributing in kidney, liver and lungs. Therefore, both methcathinone and its metabolites were distributed in imbalance among the rat tissues. Kidney was of harboring concentration-highest methcathinone, eligible as the sample for forensic identification of abusing methcathinone or relevant poisoning death case.

Synthetic cannabinoids (SCs), among the most abused new psychoactive substances, own a structure similar to tetrahydrocannabinol and ability to activate cannabinoid receptors, therewith capable of triggering more intense excitatory and hallucinogenic effects. SCs are mainly detected for identification of drug-related criminal cases about those evidential materials from plant, hair, blood, urine and other biolgoical stuffs. Presently, electronic cigarette oil has sometimes been found of illicit addition of SCs, leaving it into requirement of forensic identification. Liquid chromatography-mass spectrometry (LC-MS) is used most widely for SCs to be separated and detected. Here, a method was established for rapid qualitative and quantitative determination of 58 synthetic cannabinoids from electronic cigarette oil by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The suitable liquid chromatographic column was selected to optimize the chromatographic and mass spectrometric conditions. The electronic cigarette oil, spiked of 58 SCs standards, was extracted with methanol and then undergone into separation by pentafluorophenylpropyl (PFPP) column (100 mm×2.1 mm×5 μm) through the buffered solution of gradient-eluting acetonitrile and 20 mmol/L ammonium acetate plus 0.1% (V/V) formic acid. Under the electrospray positive ion sourcing (ESI⁺) mode, the dynamic multiple reaction monitoring mode (d-MRM) was adopted to determine the peak area of characteristic ion fragments from the external standards. The experimental results showed that the 58 synthetic cannabinoids were of good linear relationship in the concentration range of 0.5~50 ng/mL, having R² greater than 0.99, detection limit (LOD, S/N=3) and quantitative limit (LOQ, S/N=10) as the respective 0.5~1 μg/g and 2 μg/g, together with the average recoveries as 89.9%~144.0% and relative standard deviation less than 15%. Matrix effect turned out 78% of the tested synthetic cannabinoids being enhanced and the others inhibited. Alternately, only 5% of the tested synthetic cannabinoids were of strong matrix effect and the others of medium or weak. Fortunately, matrix-matching standard curve correction had effectively reduced the influence of matrix effect. The established method was also applied into detecting the electronic cigarette oils provided from actual cases, having the involved six synthetic cannabinoids accurately screened and quantitatively detected. Therefore, an expectation could be put on the method to use for rapid determination of synthetic cannabinoids illicitly added into electronic cigarette oil with its merits of simple operation, wide detection coverage, less time-consuming, high accuracy and low detection limit.

Simulative explosion is usable for restoring the course of involving event and reconstructing the relevant case scene. Hence, three choices of LS-PrePost-based simulative modeling were here tried about explosion with spherical charging: the keyword *LOAD_BLAST-guided, the SPH-directed and the keyword *INITIAL_VOLUME_FRACTION_GEOMETRY- led, thus having their advantages and disadvantages analyzed along with the applicable scenarios. All the simulations were conducted under the optimal load of 1 kg TNT charged into three different shapes so that the generated blast air-shock waves (represented with peak overpressure) were able to unfold their variations. The finite element software LS-PrePost was utilized to put into a verified finite-element model for the explosion simulation to carry out, with every simulation only changing the shape parameter of charging. The ANSYS\LS-DYNA was the solver to respond the discrepant ways of spherical, columnar and square charging in turn, having obtained the peak overpressure at diverse scaling distances, acquired some representative simulation data and delivered a statistical chart to compare the differences between every group of peak overpressure data. It was shown that there was a closer peak overpressure generated from the columnar charging and the spherical with the scaling distance less than or equal to 1.0 m·kg^-1/3, while that from the square charging and the spherical tending to a bigger difference. If the scaling distance was increasing, the ratio of peak overpressures almost kept stable from the columnar charging against the spherical, while that from the square charging against the spherical revealing gradually increasing and changing a lot. Evidently, shape-different charging does impact the generated shock-wave peak overpressure, deserving of no ignoring. Therefore, when investigating the charging with an actual explosive case and the consequent destroying effect, the explosion simulation should be carried out with the charging shape as close to the actual cases as possible. For exploration about the problems approaching to an explosion simulation, it is also necessary to choose the appropriate modeling way and charging setup so as to ensure the accuracy and reliability of the analysis and results.

Presently, such an increasing demand emerges for the identification of complex genetic relationships in forensic practice that requires the combination of a variety of genetic markers, e.g., STRs, X/Y specific indicators, SNPs and mitochondrial DNA. Next generation sequencing (NGS) approach is able to integrate multiple genetic markers into one detection system, excelling the traditional capillary electrophoresis (CE) technology in overcoming the cumbersome operational procedures and experimental handling. Here, a typing panel, designated as DNATyper^TMNGSPanel v1.0, was developed with enclosure of human 29 autosomal STRs, 36 Y-STRs, 32 X-STRs, 71 Y-SNPs and the whole genome of mtDNA. Its validation was implemented under the guidelines of the Scientific Working Group on DNA Analysis Methods (SWGDAM), having evaluated the items of repeatability, accuracy, consistency, sensitivity, mixture and species specificity. For the developed DNATyper^TMNGSPanel v1.0, a consistency of 99.72% was shown to the detection with CE, plus the complete identical results coming true between the genic loci shared with it and the Forenseq™ DNA Signature Prep Kit. No allelic loss occurred to the DNA template of 0.5 to 10 ng, yet the respective 2 and 9 loci being lost with the 0.25 ng and 0.125 ng of template. Regarding to the mixture of male and female substances, the mixed ratio of 2׃1 had the the female’s begun to appear allelic loss, contrasting that the mixed ratios of 9׃1, 4׃1, 2׃1 and 1׃1 brought the positive detections to 54.72%, 81.13%, 98.11% and 100%; and the mixed ratio of 1׃4 made the male’s happen to allelic loss, opposite the mixed ratios of 1׃1, 1׃2, 1׃4 and 1׃9 rendering the positive detections to 100%, 100%, 90.24% and 82.93%. The test of species specificity proved that the developed DNATyper^TMNGSPanel v1.0 hardly amplified the DNA from pig, cattle, mouse, either the cynomolgus monkey or the rhesus one. In conclusion, the developed DNATyper^TMNGSPanel v1.0 is of high detection throughput, high sensitivity and stability, accurate and repeatable typing and good ability for mixed sample to detect. Also, it can deliver the genetic information related to paternity and maternity at the same time in just a single run of test with any common biological samples, hence eligible for boosting the capability of individual identification and efficiency of consanguinity determination.

More STR-locus enclosure is beneficial and favorable for forensic genetics to select an STR testing kit. Thus, such a purpose-oriented STR multiplex amplification system was here to establish with a combination of 39 autosomal STR loci and the Amelogenin dyed by 9-color fluorescent substances attaching to their primers, along with its forensic value being validated about the practical application including the DNA samples difficult to handle. Based on the recommended criteria for core locus/loci among Chinese populations and actual case requirements, the candidate STR loci were screened over their eligibility, together with the primers being designed. Nine-color fluorescent dyes were used to label the relevant primers. Then, purpose-different various PCR reactions and optimization process were performed to have the STR multiplex amplification system constructed. Sequentially, validation experiments were carried out into the newly-constructed system to evaluate its sensitivity, species specificity, stability and other crucial indicators including the ability to profile the STR genotypes of the samples from real cases. Therefore, a 9-color fluorescent multiplex STR amplification system was successfuly constructed, containing 39 autosomal STR loci and the Amelogenin (28 loci<300 bp). The system was validated of being well-balanced with a sensitivity of 0.125 ng and tolerance to commonly-met PCR inhibitors, the minimum ratio of distinguishing two-gender mixture being 1׃4, and suitability for testing different types of case samples. The system also demonstrated its profiling STR-locus genotypes were truly consistent with those obtained from the commercial kits of same kind. Moreover, the system was proved of fine species specificity. As presumably the first time till present of adopting 9-color fluorescent labeling design, the system has enclosed more loci into one single test, hence attaining large efficiency. Essentially, the system is mainly composed of miniSTR, therewith making it good at detection of trace and degraded DNA samples.

Chimerism or mosaicism implicates the presence of two or more genetically-distinct cell lines in the same one organism. A father, involved with a case about searching for his son, was found to be a chimera. Therefore, his multiple STR loci were detected to explore the resulted genotypes, and followed to ascertain the causal mechanism plus patterned chimerism with different tissues from the chimera. The results showed that the chimeric father is a tetragametic chimera who was presumably formed during the course of his maternal impregnation of him where the occurrence of parthenogenetic division of his mother’s duplicated oocyte happened to fertilization with two spermatozoa and supervened of inosculation of the two feritilized ova. The chimera displayed discrepant STR genotypes with the samples from his different tissues due to diverse distribution of the two inosculated cell lines. The sought son has finally been determined through the genotypes detected from the chimera’s semen, accodingly bringing the searching-son case into end.

Nitroglycerine (NG), also known as glyceryl trinitrate, can be used to make explosives and gunpowder. The NG-derived explosive is usually of great energetic power. At present, nitroglycerin is mainly determined with gas/liquid chromatography-mass spectrometry. However, nitroglycerin is prone to complete explosion, high heat sensitivity and easy volatilization, resulting in the existing laboratory technology difficult to detect the NG-derived explosive eligibly. Fortunately, fluorescence detection can have the NG-drived explosive residues determined sensitively and rapidly. Here, a set of photonic crystal functional system was prepared to get the designed probe enhancing its emitting fluorescent signal that was yet able to quench with NG or substance from organic NG-explosive, hence realizing the highly sensitive detection of NG or organic NG-explosive through discrimination of the changing fluorescence intensity. With the core-shell nanosphere of polystyrene@silica as matrix, the silica hollow-sphere photonic crystals were prepared under self-assembly, then doped of Rhodamine 6G fluorescence probe solution into the photonic band gap at the appropriate wavelength to form a photonic crystal fluorescence sensor, finally. Excitated through the 365 nm-wavelength light, the fluorescent probe will emit an amplified fluorescent signal owing to the band edge and slow photon effect of the photonic band gap, whereas a quenching effect would be appearing on the fluorescent signal if nitroglycerin was present in the solution of probe. Through analysis of the quenching response, nitroglycerin or its sample can be detected quickly, and so can NG-derived explosive. According to different quenching effect of concentration-various samples, nitroglycerin and/or NG-derived explosive can be realized of semi-quantitative detection. Fluorescence detection has the advantages of high sensitivity, good selectivity, fast response speed, high stability and simple operation. Photonic crystal fluorescence sensor is of good universality, capable of improving its sensitivity via screening specific fluorescent probe or sensor array-defined interactive response, therefore bringing forth a good application prospect for forensic on-site rapid detection of explosives.

Hiemal fire heating and pickles eating could sometimes make carbon monoxide and nitrite co-occurrently appear into some specific living conditions, resulting in the relevant poisoning incidents. However, both the carbon monoxide and nitrite are usually such low of their concentration in blood that it is difficult to judge the true cause of poisoning from just one and/or two of them by the superficial symptoms on corpse because nitrite will affect the accuracy of the commonly-used ammonia method to determine the carboxyhemoglobin harbored with blood. Through exploration of influence of content-different nitrite on ammonia-determination of carboxyhemoglobin and the involving mechanism, this paper was purposed to provide support and principle reference for accurate qualitative and quantitative determination of carboxyhemoglobin via ammonia under elimination of interference from nitrite and other analogous substances. With ultraviolet visible (UV-Vis) spectrophotometer set at the advanced reading mode, the carboxyhemoglobin was respectively ammonia-determined of its contents in series of blood samples without nitrite and with addition of concentration-various nitrite, hence having the reasons explored into why nitrite influences the determination of carboxyhemoglobin via ammonia and the content threshold of influence. The presence of nitrite in blood does lead to false positive results when the blood-harbored carboxyhemoglobin is determined via ammonia with UV-Vis spectrophotometer, or have the content-low carboxyhemoglobin increased of its determined value. Nevertheless, the carboxyhemoglobin, if high concentration in blood, will receive less influence and just decrease its determined value slightly, thus leaving behind an overall relatively tiny effect. In principle, the content of carboxyhemoglobin is determined via ammonia through the calculation based on subtraction of the absorbance of carboxyhemoglobin at the corresponding wavelength from that of oxygenated hemoglobin. Therefore, with ability of the co-existing nitrite to have the oxygenated hemoglobin decreased of its content and the consequent absorbance, the ammonia method is certainly not able to deliver the accurate qualitative and quantitative determination of related carboxyhemoglobin. Accordingly, when there is the possibility of co-existence of carbon monoxide and nitrite or other analogous substances at a case scene, the comprehensive judgement should manage to consider the carboxyhemoglobin content and chemical properties of all involving substances so as to prevent misjudgment.

Electronic surveillance has presently covered almost all areas in China's most cities and produced enormous quantity of videos every day since Ping'an (meaning safety) project has been continuously being extended and promoted nationwide. Such the surveillance videos are important social security resources which await inspection and processing that is yet an obvious burden for human manual operation. Therefore, if the surveillance videos can be classified to discard the redundant video data and make those difficult video data easy to access, the task of inspection and processing would be comparatively welcoming and interesting. Artificial intelligence (AI) is capable of having the surveillance videos processed automatically. Indeed, there are algorithms designed for classification into natural, urban and indoor scenes. Accordingly, AI is worth adopting to classify the surveillance video scenes and further screen out those involving with crime events that public security police are to solve. Hence, a classification algorithm was here proposed about surveillance video scenes based on C3D (3D convolutional neural network) and CBAM-ConvLSTM (Convolutional Block Attention Module-Convolutional Long Short-Term Memory Network), purposing to effectively seek out crime events from the surveillance videos. Firstly, C3D was used to extract the surveillance videos to cull the local spatio-temporal features which to further highlight those more important through combination of the 3-dimensional spatiotemporal/channel attention mechanisms. Secondly, the extracted video features were sequentially input to the CBAM-ConvLSTM to pick up those global spatial/temporal features. Finally, a classifier was chosen to classify the input videos according to the global features. The method was tested and validated into the self-built crime event dataset: Crimes-mini and the public violence dataset: Hockey, showing the accuracy at Crimes-mini reaching to 92.19% with the related F1 value as 90.40% and that at Hockey to 99.5% with the F1 as 99.5%. The results demonstrated that the method proposed here is able to effectively classify crime events and violent behaviors among the surveillance videos.

For investigation of video cases/events, such occurrence is often met as videos have been snapped from long distance and/or deflected angle, resulting in either naked eyes to hardly detect key video information or video scenarios unable to explain clearly. Only relied on methods of video enhancement, can neither these problems be solved nor key information obtained about the case. To address this issue, an approach was here proposed with video data analysis. Similar to the technical ideas and methods adopted with the other popular applications and practice about data analysis, the involving video was converted of its key changing contents into fluctuant parametric data representing the video's color space, hence having the video's key changing contents reflected with the fluctuating data along with time elapsing. This method has achieved remarkable feats in investigation of some difficult video cases. Valuable reference should be also offered for peers to expand their ideas about video analysis.

In this paper, the injury mode of skull fracture was biomechanically analyzed with the finite element method so that the related injury mechanism was to deduce for exploration about an auxiliary technology that is helpful for visual and quantifiable appraisal into injury mode. For an actual case, the finite element method was used to simulate and compare the stress distribution on the skull befallen by high falling and hollow steel pipe hitting: 1) when high falling, the stress distribution on the left top of the head of THUMS4.02 (Total Human Model for Safety4.02, an imitated human figure) that was touching down onto the ground at a speed of 8.04 m/s; 2) when hollow steel pipe hitting, the stress distribution on the left top of the head of the model that was being hinted at a speed of 5.8 m/s. The simulation results were compared against the case circumstance to analyze the injury mode of skull fracture from the perspective of biomechanics. The results show that the stress program showed that the stress had just started from the part where the skull was at touching the ground during a high falling. The stress was transmitted outward with the collapse of the skull until the final formation of a circular stress area. In contrast, the hollow steel pipe hitting made the stress first distributed at the touched area between the steel pipe and the head-on occurrence of striking, leaving the stress distribution showing not obvious in the central area/point. Combined with the actual case of the concave shape-conical fracture on the left parietal bone, the force was indicated to be pushed towards the center of the circle and inward further. Therefore, the comprehensive analysis suggested that the left parietal concave fracture was formed from falling. At the same time, the conclusion obtained through the finite element method simulation was understood and accepted by the deceased's family when the injury formation was explained to them. The nodule area on the top of the skull, being the most prominent, makes it able first to touch (actively or passively) an approaching plane object (if any), resulting in an inward concave deformation and, finally, a conical fracture. The finite element method can afford a visual and quantitative analysis for the injury mode of concave/depressed skull fracture, which is a good auxiliary tool for similar forensic injury analysis.

A method was here established for determining the copy numbers of multicopy Y-STR loci which to be also explored about the efficacy for familial investigation maneuver in relevant cases. Three reference genes of BPY2, DAZ and CDY1 were selected to amplify with the investigated male-pedigree samples bearing abnormal profiles related to three multicopy Y-STR loci (DYF399S1, DYS464, DYF371). Ratios were obtained with measuring and comparing the peak areas of the above genes against those of their homologous ones from the electropherograms of the amplified products, hence rendering the expected ratios by which whether the copy number had varied was to analyze for each of the three multicopy Y-STR loci. The measured copies of reference genes were consistent with the expected for most of the tested samples, indicating that the reference genes are eligible for determining the copy numbers of the three selected multicopy Y-STR loci. Y chromosomal deletion or duplication patterns can also be estimated for the investigated samples if the above results are to combine with the chromosomal locations of related multicopy loci. The method provided here is convenient to determine the abnormal profiles of multicopy Y-STR in relevant samples from cases. A novel familial investigation strategy has therefore been suggested about taking multicopy Y-STR into consideration. Certainly, the abnormal profiles of multicopy Y-STR loci should be paid much attention with the ever-increasing inclusion into forensic application of such Y chromosomal STR loci that are prone to occur with deletions and duplications.

In all kinds of shooting incidents, it is more common for ricochet to cause casualties or property losses. At the scene of ricochet shooting, the bullet head and relevant marks have been deformed to varying degrees, affecting the trace inspection and on-site ballistic analysis. This paper investigates and analyzes the jumping bullet scene caused by a police officer’s 92 pistol shooting in the process of law enforcement, introduces the quantitative characteristics of the jumping bullet trace into the gunshot jumping bullet analysis, and tests the size and morphological characteristics of the jumping bullet point trace and the bullet deformation surface trace. During the process of jumping bullet shooting, the bullet head penetrated multiple wooden objects. By measuring the size and distance of the firing entrance and exit traces and the jumping points on the relevant objects, the incidence angle and the rebound angle of the jumping bullets are accurately calculated. The ballistic analysis is carried out in combination with the site layout and distance, and the location of the firing points and firing angle are restored, providing a scientific basis for ascertaining the nature of the case. This paper provides a reference for the investigation, evidence collection, and event characterization of such incidents.

The rapid development of iris recognition technology has been bringing iris into becoming an ever-emerging biometric feature for identity verification. The recent application of iris recognition in public security has even delivered lots of relevant researches for forensic science. Comprehensively, the current iris identification builds on solving the following two problems: 1) What features are eligible of the basis for iris identification; 2) How many iris features are required for iris identification. As iris texture is divided into three characteristic shapes: block, linear and ring, thus the iris identification is decided with these shapes. For the second problem, this paper tried to conduct a research into the block-shaped iris feature to statistically analyze the similarity among the heterogeneous origins of such feature. Firstly, the iris image was collected and normalized through elimination of the background noise by tophat algorithm, hence having the block-shaped feature extracted. Successively, the block-shaped features were described of their similarity based on Hu-moment feature and position-oriented coordinate information. Statistical analysis was followed to carry out into the gathered 952 sets of iris image data. The results showed that there was a likelihood of 4.38%／0.534%／0.043 7%／0.003 53% for two different irises to simultaneously appear one/two/three/four similar block-shaped feature(s). Depending on the capacity of the iris database, the above four likelihoods could be of small or large values. If more parameters were to describe the feature shape from multiple angles plus

more experimental data, the statistical probability would be more accurate and actual. The method proposed in this paper is of value about how many iris features should be taken to distinguish identity for identification purpose.

Fluoketamine, a new psychoactive substance from phencyclohexpiperidine, is of anesthetic effect similar to ketamine. Criminals ever took legal loophole to adventruously sell fluoketamine as a substitute for ketamine until the drug has been put into the control list in China. According to the sewage monitoring data relating to drug consumption by law enforcement departments, fluoketamine has already become one most abused drug following to heroin and methamphetamine, and even spread rapidly. Animal experiments have shown that the main metabolite of fluoketamine is norfluoketamine in vivo. In China, there are few reports about the test of in-vivo fluoketamine and norfluoketamine with the exception of testing some in-vitro samples. Thus, the solid supported liquid-liquid extraction (SLE) was here adopted via combination of liquid chromatography/tandem mass spectrometry (SLE-HPLC-MS/MS) to simultaneously detect fluoketamine (F-ketamine) and its metabolite norfluoketamine (F-norketamine) in blood and urine. For the two drugs to be better extracted from blood and urine, a comparison was conducted about the effects of liquid-liquid extraction (LLE), solid-phase extraction (SPE) and solid-phase supported liquid-liquid extraction (SLE), demonstrating SLE was the best. With the extracted F-ketamine and F-norketamine, HPLC-MS/MS was utilized to detect them. Both the F-ketamine and F-norketamine had a good linear relationship to peak area (R²>0.997 2) when their concentrations ranged among 0.5~200 ng/mL in blood or urine, with their blood delivery as LOD values being respective 0.05 ng/mL and 0.01 ng/mL; contrasting to their urine's as LOD values showing 0.01ng/mL and 0.005ng/mL. The method is of simple operation, low matrix effect and high recovery rate, capable of determining F-ketamine and F-norketamine in blood or urine.

The composition of blood stains at the crime scene contains important information in many cases. Through the detection of blood components and the inference of the source of blood stains, it is helpful to the analysis and judgment of the nature of the case and the technical support of court proceedings. Based on the biological function of different tissues and the differences in biological metabolism, the stable endogenous small molecules in blood from different tissues can be an important basis for identifying the origin of blood tissues. In this paper, ultra-high performance liquid chromatography and mass spectrometry (UHPLC-MS) were used to analyze small molecule compounds. Through the pre-treatment of peripheral blood and menstrual blood samples, liquid separation and enrichment, and high resolution mass spectrometry, a variety of data analysis methods were integrated to screen out characteristic small molecules that distinguish peripheral blood and menstrual blood. Seven characteristic small molecules in peripheral blood and four characteristic small molecules in menstrual blood were identified combining with the human metabolome database (HMDB). The established UHPLC-MS method was applied to the detection of 10 blood samples, and the accurate identification results were obtained. Therefore, the method established in this paper can provide a new technical means for the identification of blood tissue sources in actual cases.

The derivation was here carried out about the formulas of grandparent-plus-grandchild index (GI) and average power of random grandparent exclusion (RGE) under two conditions: indefiniteness of both double grandparents and mother; uncertainty of double grandparents, along with the resultant RGE formulas being empirically validated in principle. The formulas of RGE and GI were to derive on their own definition of indefiniteness of both double grandparents and mother (RGE_DGAM & GI_DGAM) and uncertainty of double grandparents (RGE_DG). The derived formulas were to calculate into 15 STR loci from Identifiler kit. Furthermore, the simulated determination was to carry out about RGE_DGAM, GI_DGAM and RGE_DG through multi-group operation with the same 15 STR loci. Finally, the formulas of RGE_DGAM and RGE_DG were to empirically validate in principle with correlation approach to the relevant values of formula and simulation. All the related formulas were thus derived, having those of RGE_DGAM and RGE_DG shown in accord with the simulation deliveries. For all the sorted RGEs relating to identification of grandparent and grandchild, there was an observation showing as RGE_DG﹤RGE_DGBM (uncetain Double Grandparents yet certain Biological Mother, DGBM)﹤RGE_DGAM. The here-derived RGE and GI formulas are eligible to cope with the cases of indefiniteness of both double grandparents and mother and/or uncertainty of double grandparents.

Fingerprint seals or films, made from people's real fingerprints, are at times used for related individuals to do their business conveniently, yet leaving behind the risk for violators to forge these fingerprints to seek illegal interests. At present, the fingerprint identification mainly focuses on two aspects: one is the traditional morphological comparison; the other is the emerging deep-learning recognition. Unfortunately, there is still a lack of scientific, effective, mature and stable examination methods to distinguish the genuine fingerprints from those fake ones which are often appeared with their red-ink-displayed versions on documents. In principle, genuine fingerprints definitely contain the substances transferred from their human donors, yet the fake fingerprints only contain substances from the used ink. Therefore, an identification method was here designed to discern the genuine and fake fingerprints displayed with red ink on documents, and verified of its scientificity and effectiveness through experiments. Specifically, the fake fingerprints were made via photosensitive fingerprint seals imbibing red ink and then pressing against the paper carriers, with the genuine fingerprints being prepared by relevant fingers directly pressing against red inkpad and then imprinting onto paper carriers. Both the genuine and fake fingerprints were placed for designated durations of time. The transfer medium was used to convey the red fingerprints (both geunine and fake), and treated with ninhydrin operation under two modes: one, developing the fingerprints through reaction of fingerprint-harbored substances (if present) with the fingerprint developer along with the transferring process; the other, first having the fingerprints transferred onto the medium previously soaked with related working fluids and then developed via fingerprint developer. Consequently, the transferred fingerprints were observed of their changes before and after displaying treatment (whether the Ruhemann's purple appeared on the transfer medium). The results showed that: 1) two modes were both able to successfully transfer the fingerprint substances and develop the fingerprint on the transfer medium, demonstrating that genuine fingerprint did result in the Ruhemann's purple appearing while none with the fake fingerprint; 2) the mode two displayed better processing effect than the mode one; 3) the mode two successfully transferred the fingerprints left for 1, 2, 7, 15 and 30 days, and had Ruhemann's purple emerged when ninhydrin treated to the relevant medium transferred from genuine fingerprint while none from the fake fingerprints. Evidently, there are differences in the distribution of componential substances between genuine and fake fingerprints. A method has been herewith established to identify genuine and fake fingerprints on documents based on the principle of fingerprint substance transferring, verifying that the identification can be realized with the fingerprints retained for legacy time of 1, 2, 7, 15 and 30 days.

2-Fluoro-deschloroketamine (2-FDCK), a new substitute for ketamine undergone into changing halogenated element and a new psychoactive substance of phencyclidine class that is being widely abused, has been presently paid of its main research on the analysis of suspected seizures and biological samples. In terms of qualitative determination about 2-FDCK, there are publications relating to the data from IR, mass spectrometry (MS) and NMR (¹H NMR, ¹³C NMR, ¹⁹F NMR). 2-FDCK’s quantitative detection primarily adopts gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, yet leaving it prone to be influenced with the factors of difficulty in obtaining the reference substance and high price. In this paper, one seizure was to identify whether it harbors 2-FDCK via the measures of confirmation of evidential structure and determination of the content of the 2-FDCK hydrochloride, with the qualitative analysis being carried out by elemental analysis, ultraviolet absorption spectrometry (UV), infrared absorption spectrometry (IR), time of flight mass spectrometry (TOF/MS) and nuclear magnetic resonance spectrometry (¹H NMR, ¹³C NMR, DEPT, ¹H-¹H COSY, ¹H-¹³C HMBC, ¹H-¹³C HSQC). Meanwhile, a ¹H quantitative NMR (¹H-qNMR) method was hence established and validated for determination of the seized 2-FDCK hydrochloride. For the method, the sample solution was prepared with fumaric acid as the internal standard and the mixture of 0.5 mL DMSO-d₆ plus 0.1 mL D₂O as the solvent. The NMR spectra were recorded through a standard pulse sequence at a pulse width of 30°. The determination temperature was set at 303 K. The relaxation delay time and the number of scans were optimized to 30 s and 16 times, respectively. The results showed that the accurate mass-to-charge (m/z) of the compound was 222.128 3 under positive electrospray ionization, with the element analysis revealing the percentage content of C, H and N elements as the respective 60.24%, 6.15% and 5.51%. The UV spectrums indicated the absorption peaks at 270 nm and 263 nm corresponded to the B band of the benzene ring, and the IR spectrums demonstrated the presence of functional groups including benzene ring and carbonyl group. All ¹H and ¹³C signals of the compound were fully attributed by combining with one-dimensional (¹H NMR, ¹³C NMR, DEPT) and two-dimensional (¹H-¹H COSY, ¹H-¹³C HMBC, ¹H-¹³C HSQC) spectra, along with the verification about the existence of the compound in the form of secondary amine salt. Based on the above results, this seizure was confirmed to be 2-(2-Fluorophenyl)-2-(methylamino)cyclohexan-1-one hydrochloride, that is, the 2-FDCK hydrochloride, indeed. More importantly, a ¹H-qNMR method was successfully established and validated, showing good specificity and durability. Within the molar ratios of 0.453 0-2.151 2, there was a clear linear relationship between the molar ratio and the integral area ratio of quantitative peak, turning out the correlation coefficient (R²) of 1.000. The final content of the seized 2-FDCK hydrochloride was measured of 99.86%. Accordingly, the complete spectroscopy data of 2-FDCK hydrochloride were obtained through utilization of various analytical techniques, and a ¹H-qNMR method was successfully established for determination of the absolute content of 2-FDCK hydrochloride in the seizure, eligible as a reference for quantifying arylcyclohexylamine derivatives. Evidently, when a reference standard is absent or difficult to obtain, NMR approach will be a powerful tool for an unidentified substance to carry out into qualitative and quantitative analysis.

Vertebral artery injury (VAI), albeit relatively low of its incidence, is of high mortality. Vertebral artery is located in the transverse foramens, always unhurling complex structure under anatomy. Although VAI shows unobvious symptoms at the initial occurrence, its progressing paroxysm would yet lead to headache, vomiting, sensory disorder, inferior consciousness, and other neurological changes, even the fatal effect on final. Sometimes, VAI could be caused from the cervial surgery in clinical diagnosis and treatment, engendering an incident that forensic appraisal would be put up and/or of awareness. VAI can presumably turn up the blunt and/or penetrating injury, showing miscellaneous looks with direct injury, traction, torsion, sudden increase of intravascular pressure, and sometimes coexistence of multiple mechanisms. VAI can be analyzed of its resulting mechanism and progression through the examination of forensic autopsy and radiology into each segment of vertebral artery. VAI was here reviewed with purpose to improve the understanding about it and provide references for forensic peers.

Synthetic cannabinoids are of hallucinogenic effect equivalent to or even stronger than that of cannabis, being listed under the first batch of new psychoactive substances controlled in China. There are many kinds of synthetic cannabinoids, among which MDMB-4en-PINACA and ADB-BUTINACA are recently the two ones of most active alkyl formyl indazole in the market. Such two synthetic cannabinoids have presumably not been reported about their metabolic researches in China. Thus, both the MDMB-4en-PINACA and ADB-BUTINACA were here probed into their metabolites from the blood and liver of rats. With 12 SD rats randomly divided into two equal groups: one for MDMB-4en-PINACA and the other for ADB-BUTINACA, each rat was fasted for 12 h and then intraperitoneally administered once by weight as per 1.0 mg/kg along with the two groups leaving one rat taken as the control that was not injected of drug yet executed just before administration. The remaining five rats in each group administered of drug were respectively killed at 5, 15, 30, 60 and 120 min after drug injection, having their blood and liver tissues received and successively analyzed into high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-QTOF). The results showed that the experimental rats had MDMB-4en-PINACA metabolized into corresponding metabolites through double bond oxidative carboxylation, ester hydrolysis, 4-depentenylation and hydroxylation, with ADB-BUTINACA being metabolized through hydrolysis, 4-dealkylation, 4-butyl hydroxylation and hydroxylation. According to the response intensity of components in blood and liver tissue of rat, MDMB-4en-PINACA mainly converted into its metabolites from pentenyl oxidative hydroxylation (No. M6), pentenyl oxidative carboxylation (No. M7), methyl butyrate hydrolysis (No. M2) and further hydroxylation (No. M3/M4/M5) and dealkylation (No. M1), demonstrating its metabolic markers as M1 and M2. ADB-BUTINACA mainly turned into its metabolites from debutylation (No. A1), formamide hydrolysis (No. A2), butyl carboxylation (No. A3) and butyl hydroxylation (No. A4), with its metabolic markers being as A1 and A2.

As soon as ChatGPT came out, it attracted widespread attention. This article takes ChatGPT as an example, briefly describes the use, characteristics and advantages of large language models, and analyzes the current controversies, ethical dilemmas and information security risks. This paper focuses on the analysis of the possible applications of large language models in crimes, and discusses the use of ChatGPT to assist in the acquisition of criminal skills, the implementation of cybercrimes, phishing attacks, and the dissemination of false information. This paper also explores the use of ChatGPT at the law enforcement fields, including serving crime fighting, crime prevention, law enforcement decision-making, and law enforcement capacity building. This paper believes that law enforcement agencies should keep an open attitude, pay close attention to the impact of the application of artificial intelligence technology on crime, represented by ChatGPT. Law enforcement agencies should strengthen research and deal with ChatGPT from both aspects of “positive” and “negative” attitude, applying new technologies to help with law enforcement activities and improve efficiency.

DYS460 locus was here explored about the cause of its abnormal genotyping through it being amplified with different primers. Such the samples of abnormal genotyping of DYS460 locus were collected and then sequenced for a comparison to carry out with the differential amplified sequences of the locus. It was found that there were two adjacent repeats of [CTAT]_n in DYS460 locus' sequence, rendering selection of different primers to result in discrepant repeats having been amplified and hence delivered of different final genotyping results. Accordingly, for the genotyping of loci harboring complex repeats, the guidelines should be complied with both the general designating standards of STR loci and those specific of existing commercial kits. When two sequence-identical repeats are present in an STR locus, the universal core repetitive sequence should be carefully identified of its exact position, thereby having the relevant primers' binding sites adjusted necessarily and adequately. As thus, the purposed fragment and its allelic standard will be ensured to contain the required unique core repetitive sequence and avoid abnormal genotyping caused with selection of different core repetitive sequence.

An ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) was to establish for analysis of sildenafil and its three major metabolites (N-demethylsildenafil, Descarbon Sildenafil and Sildenafil Impurity S) in human blood and urine, with its validation being carried through the collected blood and urine from experimental animals. The 200 μL samples (blood or urine) were added with sildenafil-d₈ (the internal standard substance), successively precipitated of protein with acetonitrile (800 μL) and then centrifuged to receive the supernatant. After filtrated through membrane, the supernatant was eluted into Waters BEH C18 analytical column (2.1 mm×100 mm×1.7 μm) that was flowed with the gradient elution consisting of formic acid (0.01%) plus 2 mmol/L ammonium formate (mobile phase A) and acetonitrile (mobile phase B). Such the column-separated eluate was subjected to analysis of mass spectrometer into UPLC-MS/MS apparatus under multiple reaction monitoring (MRM) mode plus positive ionization (ESI+) by electrospray ionization. The results showed that limits of detection were up to 2 ng/mL for the sildenafil and its three major metabolites in blood and urine, with their linear ranges of the four chemicals being as 5-1000 ng/mL (all rendering an r higher than 0.997) in blood and as 5-5000 ng/mL (all rendering an r higher than 0.997) in urine for sildenafil, N-demethylsildenafil and Descarbon Sildenafil plus the remaining Sildenafil Impurity S as 5-1000 ng/mL (r=0.999). The extraction recovery was the respective 102.27%-109.70%, 77.16%-106.40%, 84.22%-107.67%, 92.02%-102.59% for the sildenafil, N-demethylsildenafil, Descarbon Sildenafil and Sildenafil Impurity S in the analyzed biological samples, with the four chemicals showing their within-day precision being as the respective 6.35%-11.07%, 1.73%-9.81%, 1.53%-11.19% and 5.52%-12.51%, their inter-day’s as the 8.19%-14.24%, 1.79%-10.37%, 1.71%-12.32% and 6.41%-12.40%, and their accuracy as the individual 91.05%-103.27%, 88.00%-110.20%, 87.48%-111.31% and 95.66%-112.73%. Through qualitative and quantitative analysis into the blood and urine collected from experimental animals, the established method had been validated of ability to detect sildenafil and its three major metabolites in the tested samples, showing the concentrations of sildenafil, N-demethylsildenafil and Descarbon Sildenafil being as 27.52, 9.97 and 11.04 ng/mL in blood yet Sildenafil Impurity S having not reached the limit of quantification, with the respective concentration of sildenafil, N-demethylsildenafil, Descarbon Sildenafil and Sildenafil Impurity S being as the 203.33, 2963.84, 3550.70 and 23.87 ng/mL in urine. This approach established here is of simple pretreatment, high extraction efficiency and wide linear range, hence capable of detection for sildenafil and its three major metabolites in blood and urine from suspected sildenafil poisoning case.

Aconitum is of pharmacological effects, therewith making it be used to exert analgesic, antiepileptic and anti-inflammatory functions at clinic for years. However, aconitum is of high toxicity derived from diester-diterpenoid alkaloids (DDAs) including aconitine, mesaconitine and hypaconitine, usually leaving narrow therapeutic safety-window time. The lethal dose of aconitine is estimated to be only 1-4 mg for human adults so that homicidal and/or suicidal cases are often reported of involving with aconitum. The diester-diterpenoid alkaloids could change their structures and toxicities quickly during in vivo processing and metabolism, having become into monoester-diterpenoid alkaloids or further the alcohol amines. Thus, aconitum alkaloids deserve the in vivo research of their metabolites especially on the time when there haven’t been few studies on postmortem redistribution of aconitum alkaloids in poisoned animal. Consequently, the postmortem redistribution of aconitine, mesaconitine, hypaconitine and their metabolites (benzoylaconine, benzoylmesaconine, benzoylhypaconine, aconine, hypaconine, mesaconine) was here studied. The 18 experimental rabbits were randomly divided into six groups, being poisoned by intragastric administration. On 2 hours after administration, the rabbits were killed by trachea closing and kept in supine position at 25°C, waiting for collection of tested samples (heart blood, peripheral blood, urine, heart, liver, spleen, lung and kidney) at post-death of 0, 4, 8, 12, 24 and 48 h. The high performance liquid chromatography-tandem spectrometry was adopted to determine the collected samples, showng as urine: the benzoylmesaconine and benzoylhypaconine were respective 2.39 and 2.51 times higher of their contents at 48 h than at 0 h; heart blood and peripheral blood: benzoylmesaconine displayed an obvious upward trend, with its content being much higher in peripheral blood than in heart blood; viscera tissues: each substance was significantly higher of content in spleen, liver and kidney than in heart and lung, with hypaconitine and benzoylhypaconine showing overall content-upward trend in spleen, liver and kidney, even demonstrating highest of the two in spleen, plus the benzoylmesaconine at post-death 12 h showing an upward trend in spleen, liver and kidney. Accordingly, the postmortem redistribution of aconitine, mesaconitine, hypaconitine and their metabolites was revealed in rabbits poisoned, potential to provide reference for aconitum alkaloids poisoning cases to select samples and carry out relevant forensic identification. Evidently, urine is the most obvious biological sample for aconitum poisoning, and also harboring the highest content of each substance at the time of death, therefore prominent as the collecting sample in cases of suspected aconitum poisoning. Whereas, when the time of death is long and it is difficult to collect the liquid biological samples, the tissues of spleen, liver and kidney might be used as the canadidate biological samples in aconitum poisoning.

A 39 year old male victim was injured in the head, chest and abdomen by fist. Afterwards, his head was heavily hit against the wall and bed frame several times. During that time, he hit his right temples twice using a glass-made wine bottle. Then, he suddenly twitched and became unconscious. He was diagnosed with left frontotemporal parietal subdural hematoma, subarachnoid hemorrhage, cerebral hernia formation, and scalp contusion. The victim did not drink alcohol. After admission, an operation of removing bone flap decompression was performed to remove the left frontotemporal top subdural hematoma and repair the meninges. During the operation, dark red clot in the subdural area was found with the size of about 12 cm×13 cm, accompanying with contusion and laceration of left temporal lobe brain tissue. The victim remained in a coma for over 8 months after surgery. This article analyzes the mechanism of brain injury, the degree of participation of self-injury and intentional injuries, the identification of persistent vegetative state, and the evaluation of injury severity.

DNA analysis by capillary electrophoresis with fluorescent short tandem repeat (STR) detection plays a dominant role in DNA testing of various cases, but for difficult biological samples, such as highly corrosive and degraded bones, it is not effective due to the small number of motifs STR detected. This paper describes the application of second-generation sequencing technology in DNA testing of difficult biological samples such as highly degraded bones in forensic science practice. In a murder case that had remained unsolved for 30 years, the traditional STR testing method did not yield effective STR locus typing, but a complete autosomal locus typing was obtained by second-generation sequencing using the Precision ID GlobalFiler^TM NGS STR Panel v2 kit. However, through the second-generation sequencing method using Precision ID GlobalFiler^TM NGS STR Panel v2 kit, the genotypes of 31 autosomal loci were obtained, which helped the case unit to identify the source of the body and provided key technical support for the investigation of the case. By analyzing the advantages of NGS technology for such highly degradable samples and exploring the consistency between the STR locus typing results of CE electrophoresis detection and NGS typing results, it is shown that NGS technology can overcome the analysis limitations of CE for such highly degradable samples, supplement the shortcomings of CE technology, and provide new methods and technique for forensic DNA testing and analysis of difficult biological samples.

Nitrous oxide, chemically expressed as N₂O and also known as laughing gas appearing colorless and sweet, is widely used as an anesthetic in medical surgery. The illegal consumption of nitrous oxide occurs sometimes, resulting in the requirement of scientific test and identification to collect the relevant evidence. Although gas chromatography-mass spectrometry can be used to detect nitrous oxide, yet it always relies on those expensive instruments and relatively strict experimental conditions. Fortunately, nitrous oxide is of infrared spectral activity, making it able to apply into infrared spectroscopy. Fourier transform infrared spectroscopy (FTIR) is of fast detection speed, low cost of utilization, green and environmental protection, almost no sample treatment and nondestructive testing. Therefore, FTIR was here coalesced with gas cells to have achieved the qualitative and quantitative analysis of nitrous oxide/laughing gas, hence having the gas obtained of its typical infrared spectrum with high-purity nitrous oxide (99.9%). The attribution was analyzed about the main infrared characteristic absorption peaks of nitrous oxide. A quantity-defined injector was used to quantitatively test the nitrous oxide at different concentrations, demonstrating that the nitrous oxide concentration of 0.02% -14.54% in the infrared gas cell could come into being the characteristic adsorption peak (peak height) at 1300 cm^-1 for quantitative analysis. The working curve meets Lambert-Beer law under the peak height as a function of nitrous oxide concentration, rendering a presence of strong linear relationship at the correlation coefficient (R²) of 0.992 4. The relating detection limit showed as 0.02% and the limit of quantification as 0.10%. The data and spectra of the typical infrared spectral absorption peaks of nitrous oxide obtained in this paper can be compiled into the infrared spectrum library as a basis for qualitative retrieval of nitrous oxide to identify into unknown gases. The here-established infrared spectrometric approach is simple, fast and accurate for determination of nitrous oxide, capable of accurately and rapidly detecting nitrous oxide/laughing gas in certain places, eligible for supervision and cracking down on crimes involved with abuse of laughing gas. Besides, the approach can be applied to a portable infrared spectrometer to achieve on-site detection of nitrous oxide with reliable qualitative results.