Objective To report the first-time emergence of PMK (piperonyl methyl ketone) methyl glycidate (a precursor substance of MDMA) in China’s mainland through completion of establishing its gas chromatography-mass spectrometry (GC-MS) analytical method and confirming its structure with nuclear magnetic resonance (NMR) which to deliver the compound’s hydrogen and carbon spectrums. PMK methyl glycidate is able to synthesize MDMA (3,4– methylenedioxymethamphetamine, a controlled drug capable of seducing the eater into addiction) through transition of PMK. Methods The sample was extracted with methanol and DMSO-d6, successively subjected to detection of GC-MS and NMR. Results GC-MS rendered the characteristic mass-spectral fragments and retention time of the extracted compound with which NMR assigned the signal peaks of both hydrogen and carbon spectrums, having therewith determined the structure of the chemical substance. Conclusions At present, GC-MS technology, combined with mass spectrometric information database retrieval, is one of the most commonly used choices for analyzing drugs and their precursors in forensic laboratories. However, due to the difficulty in obtaining available reference substances against the combination of some drugs and their precursors, the absolute accuracy of retrieval results cannot be guaranteed. NMR approach is independently eligible to confirm the structures of compounds of the reference substances so as to ensure the accuracy of the identification results. In this study, PMK methyl glycidate was identified with GC-MS and NMR, having its 1 H-NMR and 13 C-NMR spectra analyzed, thus providing a reference for identification of other similar compounds. The method is simple, reliable, and suitable for qualitative analysis of PMK methyl glycidate.

Objective To establish a novel method for determination of blood-harbored ketamine and F-ketamine through liquid chromatography-mass spectrometry (LC-MS/MS), with pretreatment choice being preferentially determined from the matrix effect and successively the blood-harbored ketamine and F-ketamine to be isolated and tested of their specificity, linearity, detection limit, precision and accuracy. Methods Sampling blood (1.00mL) was taken, added with 2.00mL acetonitrile, extracted under vibration, and centrifuged, having the supernatant filtered through 0.22μm membrane before analyzed into liquid chromatography-mass spectrometry (LC-MS/MS). With their retention time, characteristic ions and relative abundance ratio for qualitative determination plus their peak area of characteristic ions for quantification, the two chemical substances were to characterize. Results Acetonitrile precipitation showed no significant matrix effect yet good specificity. A good linearity was obtained with the concentration of ketamine and F-ketamine ranging from 1.50ng/mL to 150ng/mL in blood (R²˃0.999). The detection limit of the method was 0.30ng/mL, and the extraction efficiencies of samples spiked with concentration-different ketamine or F-ketamine were 82.1%~86.5%. The intra- and inter-day RSDs were less than 10%. Conclusions A new method was here successfully developed for determination of blood-harbored ketamine and F-ketamine using liquid chromatography-mass spectrometry (LC-MS/MS). The method is simple, quick, sensitive and stable, suitable for qualitative and quantitative determination of ketamine and F-ketamine in blood.

Objective To establish an HPLC-DAD method for simultaneously quantitative analysis of tramadol, fentanyl and diphenoxylate in seized drugs and/or illegally-added herbal medicines. Methods The sample was dissolved into methanol and extracted under ultrasonic, having the obtained analytes separated through an Agilent Zorbax SB-C18 (4.6×250mm, 5μm) column that was flowed with gradient-eluting of 12mM potassium dihydrogen phosphate buffer (pH=4 adjusted by 10% dilute phosphoric acid)/acetonitrile. The analysis was completed in 30 minutes and detected at the wavelength of 210nm. Results The three chemical substances were shown of their detection limits (S/N=3) and quantitation limits (S/N=10) among 0.2~0.5μg/mL and 0.5~1.0 μg/mL, respectively. The linear relationship was good in the range of 2~700μg/mL, with the correlation coefficients (R²) being all greater than 0.999, the three-concentration average recoveries (80%, 100%, 120%) in yellow and white powdery drugs among 99.6%~105.4%, the relative standard deviations (RSD%, n=6) being less than 1.4%, the inter-day precisions among 1.19%~2.11%, the repeatability within 0.31%~1.41%, and the stability being fallen into 0.29%~0.87%. Conclusions The method is simple, accurate, precise and stable, capable of quantitative analysis of tramadol, fentanyl and diphenoxylate in seized drugs and/or illegally-added herbal medicines.

Objective To establish an HPLC-MS/MS method for simultaneous determination of sufentanil and its metabolite (norsufentanil) in human blood so as to achieve a detection of both high sensitivity, low detection limit and good reproducibility plus simple pretreatment of sample. Methods Deuterated isotopic sufentanil, the internal standard, was added into samples (blank blood, blood containing both sufentanil and its metabolite-norsufentanil) that were followed to precipitate of protein with acetonitrile, successively undergone into separation through HPLC and detection via ESI, positive ion scanning and MRM mode. Qualitative accuracy was measured with retention time and two pairs of characteristic ions while the quantitative accuracy was calculated with the curve derived from internal standard. Results The detection limit of sufentanil was 0.05ng/mL, with the limit of quantification being 0.1ng/mL, linear range as 0.1~20ng/mL, correlation coefficients being the respective 0.99984 and 0.99973, recoveries between 90% and 120%, intra-and inter-day precisions being less than 5%, and accuracy between 90% and 110%. Conclusions The method is no necessity of concentration or derivatization, hence avoiding errors caused from cumbersome operation, excelling in the advantages of rapidity, simplicity, accurateness and stableness, therefore capable of qualitative and quantitative determination of sufentanil and norsufentanil in blood.

Objective To prepare a kind of sulfur-containing polymer for its exploratory utilization into fingerprint development. Methods The sulfur-containing polymer was prepared under a designed synthesis route, having been characterized of its chemical attribution with certain related physicochemical resorts. Latent sweat fingerprints were made on copper sheet surfaces in different states, successively sealed with the synthesized polymer into a reaction bottle for condition-various development. Observation was carried out about the development effect. Results The sulfur-containing polymer was successfully prepared, having achieved of developing the latent sweat fingerprints on copper sheets where whether those fingerprints were intact or undergone with water washing or detergent washing plus sponge wiping before development. Conclusions The sulfur-containing polymer is potential to develop latent sweat fingerprint on metal (e.g., copper) surface, capable of being utilized to develop difficult-to-handle fingerprints on copper sheet surface.

Objective To develop a new derivatization method for GC-MS to rapidly determine fluoroacetate (salt) from food-poisoning samples and vomit. Methods The samples were extracted with pure water, then added of the organic solvent containing derivatization reagent (PFB-Br) into the aqueous phase so that the derivatization-synchronous extraction was achieved under the function of tetrabutylammonium hydrogen sulfate (also named as IPC-TBA-HS), a phase transfer catalyst (PTC). GC-MS, equipped with HP-5MS elastic quartz capillary column (30m×0.25mm×0.25mm), was adopted for analysis into the extractant. From the retention time of pentafluorobenzylmono-fluoroacetate (PFB-MFA) (the derivatized product), the relevant fragmented ions of m/z 181.0, 258.0, 61.0 and involving characteristic peak areas were selected as qualitative and quantitative benchmark. Results The method was showing linear among 0.1μg-10μg/ml (R²=0.9997, n=7), with its detection limit as 0.050ug/ml and recovery being more than 80%. Conclusions The developed method has been verified of time-saving, less workload, simplicity, easiness to operate and high sensitivity, suitable for frontline detection units to utilize, too.

Objective To explore the operational principle of Cartesian-coordinate writing robot about its imitative signature handwriting and related characteristics on which how to consequently influence with the robot’s parameter setting. Methods The personal man-made signature handwritings and those of the writing robot were collected, having been observed into the characteristics of the robot’s imitative signature handwritings with the help of instruments (i.e., VSC8000 and RTI here). Results As the robot’s imitating signature handwriting is designed on Bezier curve and consecutively converted into G instructional code to control the robot to carry out writing, a highly consistency exists between the robot’s imitating signature handwriting and the one of personal man-made about their general features, local arrangements and writing-regulated features, yet the differences being present among their allocable proportion, repeated strokes, stroke order, pen’s running route and marks. Strokes’ jitter will result from the larger parameter setting of acceleration and speed. With the pen pressure-parameter augmenting, the pen marks maintain from gradual deepening to remaining unchanged. The pen’s closing stroke is to elongate along with the pen pressure/stroke parameters augmenting. Conclusions There are essential differences present in writing principle and handwriting characteristics between the robot imitative signature handwriting and the one of personal man-made, laying a feasibility for identification about such kind of signature handwriting.

Objective To measure the motion and stability of knee joint in three-dimensional space with Euler angles so as to provide a theoretical basis for gait classification and recognition with new-discovered gait features. Methods The Codamotion three-dimensional motion capture system was used to record the movement and activity confine around the marked legs’ sites of the subject who made 20 rounds of natural walking course, thereby having calculated the Euler angles (X: of adduction and abduction, Y: of internal and external rotation, Z: of flexion and extension) of left and right knee joints. The knee joints were therewith explored of their sports situation. Results Through Spearman analysis being conducted into the calculated Euler angles of knee joints from same person who made multiple rounds of walking course, the coefficient r was received with its 88.60% falling into high correlativity scope and the remaining 11.40% leaving among the significant correlation degree. During the period of single-foot/bipedal support, the swinging/rear-supporting leg led out more stable Euler angles X and Z of knee joint than the supportive/front-supporting leg whose Euler angle Y was yet more steady. Conclusion Same person, when naturally walking into rounds of course, is able to maintain his/her knee joint movement within a certain degree of stability.

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.

Objective To probe into the applicability of telecentric lens in photographing evidential traces by way of comparative experiments. Methods Under the identical light circumstance, the same surface was respectively photographed with a conventional magnification-constant camera equipped of lens of either macro or telecentric. The comparison was made into the items of field depth, definition, deformation, and edge fidelity of the shot images. Results The conventional macro lens rendered poor field depth when the large aperture as the choice, in contrast to utilization of small aperture (F/16) having achieved the improved field depth yet occurrence of deformation, the decreased clarity and nonuniform brightness. The telecentric lens delivered the shot image of better balancing in both the field depth and deformation together with the even brightness and high sharpness. Conclusion The telecentric lens is of certain applicability in photographing evidential traces.

Objective To establish a method for detecting blood-harbored glufosinate ammonium through derivatization to undergo into GC/MS analysis. Methods Glufosinate ammonium was extracted from whole blood with methyl alcohol/acetonitrile (2/8, V/V), successively subjected to evaporation at water bath of 80°C, consecutively having its residues resolved into methyl alcohol with which the same amount of acetic anhydride was followed to add for derivatization to perform under the time and temperature respective of 1h and 80°C. Finally, the derivatized product was dried and then resolved with acetonitrile (0.2mL) for detection of GC/MS along with external standard. Results With derivatization of acetic anhydride, the tested glufosinate ammonium got its correlation coefficient about 0.993 from the linear curve within concentrations ranging among 0.5~10µg/mL, having the relative standard deviation of 3.2% (n=3) and limit of qualification of 0.2µg/mL (S/N = 45/1). Conclusion The method is simple and reliable for qualitative and quantitative analysis of glufosinate ammonium in whole blood.

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.

Objective To develop a method for identifying 5F-AB-PINACA, 5F-AMB, AB-FUBINACA and AMB-FUBINACA of novel synthetic cannabinoids (SCs) through approaches of GC-MS, LC-MS/MS, FTIR (Fourier transform infrared spectroscopy) and RS (Raman spectroscopy). Methods GC-MS was adopted to analyze the methanol-dissolved reference substance (enclosing 5F-AB-PINACA, 5F-AMB, AB-FUBINACA and AMB-FUBINACA) that was further diluted with ultra-pure water for LC-MS/MS analysis. For FTIR and RS analysis, a small quantity of reference substance was directly placed onto ATR affix or glass slide to undergo consecutive detection. Results For either 5F-AB-PINACA against 5F-AMB or AB-FUBINACA against AMB-FUBINACA, their respective characteristic fragment ions are very similar under both GC-MS and LC-MS/MS, with the relevant fragmentation mechanisms being briefly described. Through FTIR and RS, the infrared absorption peaks and Raman displacement peaks of the two substances from each compared pair are of single-one-cannabinoid-based high specificity and selectivity with their individual various modified functional groups. Conclusion Simultaneous application of chromatography-mass spectrometry and spectroscopy into identification of novel synthetic cannabinoids is eligible for providing data able to confirm with mutual reference.

Compared with capillary electrophoresis (CE) technology, next generation sequencing (NGS) can accommodate more STR genetic loci within the relevant system, therefore emerging as a promising and potential technology for forensic practice. Illumina’s MiSeq FGxTM system is a sequencing platform dedicated to forensic services, with its supporting kit - Forenseq DNA Signature Prep kit having achieved higher sensitivity and accuracy. 41 pedigree samples were here reported of being sequenced with the kit mentioned above. The results showed that 26 of the tested 58 STR loci had come into being allelic subtypes, bringing forth the total number of alleles to increase by 79. There was one sample showing a dropout at the DYS392 locus against to its CE presentation, being speculated of correlativity with amplification efficiency of the kit’s primers. Besides, eight samples were found of inconsistency with CE results at the DXS7132 locus. Sanger sequencing was thus conducted and data were analyzed with other software to explore the causation. It was confirmed that the inconsistency resulted from irrelevant bioinformatics analysis. This study has proved that NGS owns many advantages over CE although it still awaits solutions about some issues in bioinformatics analysis. With the ever-coming continuous improvement of related technologies and standards, NGS is believed to be gradually applied into forensic practice.

Objective To establish a novel amplification multiplex of 13 rapidly-mutating (RM) Y-STRs (the known and utilized thus far), and to assess its forensic applicability and capability. Methods A set of new 5-dye Y-STR multiplex system was tentatively developed to amplify 13 RM Y-STR loci (DYF387S1, DYF399S1, DYF403S1, DYF404S1, DYS526, DYS449, DYS518, DYS547, DYS570, DYS576, DYS612, DYS626, DYS627) through optimization of fluorescence labelling, primers designing, constituents concocting and amplification setup. One recommended nomenclature was concluded on the basis of reviewing into peers’ published normalizations and Sanger’s sequencing. The multiplex system was validated with determination of sensitivity, species specificity and stability plus its performance for detecting the mixed DNA samples. Results One novel RM Y-STR amplification multiplex was successfully constructed, demonstrating its optimal annealing temperature of 59°C and cycles of 28. A recommended nomenclature for the RM Y-STR loci was concluded from summarization. Full profiles of the selected Y-STR loci were still obtained down to a low level of template DNA (0.125ng). Besides, the multiplex system was of species-specific and robust to tolerate concentration-high PCR inhibitors (i.e., EDTA, hematin, humic acid and indigo with this assay). Furthermore, the system was able to detect complete male specific genotypic profiles in a male/female DNA mixture at a ratio of 1∶4000, and so was it for male/male ratio-various DNA mixtures to display mutually. Conclusions The RM Y-STR multiplex developed here is of forensic applicability, very suitable for both fine searching into male lineages and complementing to currently-used Y-STR kits.

At times, document examination requires identification about intentional falsification into a document that was formed with inkjet printer to print its original version previously yet conduct added printing to engender the modified one afterwards. Such an identification involves with the techniques about how to authenticate both the printed document and the time to have the document formed. Rationally, it is necessary to analyze the document with its relatively stable and abnormal features so that the discrimination can be carried out between them, leading to a reliable identification. This paper dealt with an actual case of this kind. Through thorough analysis of the periodic occurrence of ink dot in the printed graphics and text, three abnormal features were found in the document, having resulted in a conclusion for their forming reasons based on the mechanism of inkjet printing. Therefore, the evidentially supporting proof was provided on whether the document was given birth from only one time or not.

At times, cases are suspicious of relating to death from poisoning, yet the traditional toxicological testing is difficult to carry out due to the corpses having decayed into skeletonized remains, fragmented and/or decomposed thoroughly, resulting in unavailability to extract the poisoning chemicals. Accordingly, skeletal tissue is then the only left material for the poisoning substances to extract with such cases although it is not a current welcome sample about doing so. However, skeletal tissue is advantageous in preventing against contamination and decomposition, leaving the potential for toxicological analysis to have the depositing-into-bone toxicants refined with novel and ingenious innovations so that the cold and difficult-to-solve cases could be settled someday. Definitely, the recent publications truly present such endeavors about making the road put through. This paper reviews the comprehensive actuality about toxicological analysis into skeletal tissue. Firstly, the suitable skeletal tissues were commented from the relevant publications, together with their applicable methods including the pretreatment (e.g., cleaning, drying, crushing and extraction) and instrumental utilization. Secondly, the animal experiments were summarized about the drug distribution and metabolic changes in skeletal tissue under different environmental conditions. Thirdly, targeting to the discrepant drug concentrations between marrow and mineralized bone, the adequate treatments were discussed for separating marrow from mineralized bone so as to independently assess the value of a particular skeletal tissue type in detection of a given drug. Finally, suggestions and prospect were put forward about both the problems waiting for solution and progressive trend, having emphasized the mechanism of drug incorporation into skeletal tissue, which drugs can be detected in skeletal tissue, which type of or certain bone is suitable for toxicological analysis, and the others related.

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.

Great challenges have been being brought to the fingerprint identification systems into their matching accuracy and speed with the so-called big-data collection and entries of billions of fingerprints. Forensic experts and practitioners expect an automatic fingerprint recognition technology (also known as non-minutiae-based matching) would be applied so as to eligibly search out the matched fingerprint from the fingerprint gallery with just an intact shot-on-the-scene image of fingerprint. YUNHEN, an intelligent fingerprint identification system, has thereby been smartly created for coping against the above-indicated challenges. It is an innovative facility, taking the advantages of self-adaptive wavelet algorithmic framework, proactive deep learning and BUS synergy, so that it can realize the approvable accuracy and speed of fingerprint matching among a billion-level data gallery of fingerprint. Exampled with the policing practical utilization, YUNHEN system was here introduced into its actual scenarios of fingerprint matching applied throughout the ends of computer and mobile phone. Accordingly, such an artificial intelligent operational facility was compared and analyzed against the traditional fingerprint identification system on terms of delivered fingerprint information capacity and accuracy, demonstrating its overwhelming advantages. Finally, prospect was envisioned about the application of artificial intelligence into fingerprint identification.

Objective To scrutinize the electronic data changing with its related smart lock which to unlock through Tesla coil so that the key points of crime scene investigation and suggestions are thereby to put forward. Methods A smart lock was disassembled to explore its both fingerprint/password storage chip (MCU: micro control unit or EEPROM: electrically-erasable programmable read-only memory) and mode, consequently having undergone repeatedly to unlock with a Tesla coil such that the data in the lock’s chip were recorded for comparison before and after the unlocking. The hardware-circuit communication of the lock was examined to ascertain which communication mode had been interfered with the Tesla coil. An arbitrary waveform generator was adopted to simulate the interfered communication mode from which the resulting changes were recorded and compared against those caused through Tesla coil disturbing. Consequently, the reason why Tesla coil can unlock the smart lock was to discover. Results The fingerprint and password are found of being stored in EEPROM of the selected smart lock, with the password being kept in the storage mode of plaintext. There are three communication modes of IRQ (interrupt request line), SCL (system clock line) and SDA (static data authentication) between the smart lock’s panel board and MCU. When a Tesla coil opens the smart lock, the communication signal has changed, causing the IRQ program unable to get through and/or being disordered so that all the stored data of password and fingerprint have been completely erased from EEPROM, leaving the door open. Conclusions Tesla coil can interfere the communication signals of smart lock, resulting in the lock’s stored data of password and fingerprint being completely erased from EEPROM and the lock being opened automatically. For crime scene investigation, whether a smart lock has been opened with Tesla coil can be inferred through checking if there is occurrence to changing with the data stored in EEPROM of the lock.

Objective To develop a GC-MS/MS method for determination of 2′-diclazepam in blood. Methods The sampling blood was extracted via HLB cartridge (a product from Waters Corporation, enabling operation of the auto-SPE (solid-phase extraction) for this determination) that was eluted with ethyl acetate, having the collected eluate subjected to GC-MS/MS analysis. Results For the 2′-diclazepam tested, a linear relationship was present between the concentration and peak area from the calibration curve in the range of 20~20μg/mL, demonstrating the limit of detection (LOD) being 10ng/mL. Moreover, the average recoveries were shown within the range of 81.8%~90.4%, and the relative standard deviations among 4.89%~5.47%. Conclusion The here-established method is of high sensitivity, selectivity and strong operability, suitable for determination of diclazepam in blood.

X-ray fluorescence spectrometry (XRF) is one approach commonly applied for element analysis, capable of distinguishing the types and contents of elements in the tested sample. XRF is therewith of wide forensic utilizations. This article reviewed the application of XRF into examining documents from the respective paper, writing/printing inks, banknotes and paper cultural relics, having summarized the XRF-based identification of document authenticity, concatenation, traceability and chronicling. Additionally, an introduction was carried out about the mathematical statistics adopted in quantitative analysis of elements, together with the qualitative analyses of various apigments. Finally, a prospect was envisioned on further application of XRF, with the concerned key issues and future trend being discussed, too.

In recent years, the new-type telecommunication network crimes have occasionally caused huge losses to the people's lives and properties, posing more workloads and challenges to both the law enforcement authorities and social public security. Here is a typical real case of infringing citizens' personal information by way of online lending platform. The investigators adopted the means of mobile application-data capture, APP decompilation, source code analysis, mirror-image file-format conversion and emulation, database backup and restoration, therewith having collected and fixed the evidence so that the suspects were successfully targeted. Focusing on the digital forensic process, this paper mainly demonstrated how to acquire hundreds of millions of data with which the key clues and evidence were managed to provide. The experience and practice conducted here would be useful and reliable for police digital forensic investigators to solve the similar telecommunication online crimes.

Surveillance video would be difficult to provide strong evidence with correlating some particular actions/behaviors of certain gang-fighting participants into the circumstance of case (e.g., incoherence to the autopsy Results) when the video is of ineligible quality and resolution and/or its then recording was influenced with the crowd, environment and light. From investigation of a typical case where the event sequence was caught in the video recorder on crime scene, the pertinent matters were here explored. An introduction was firstly made about the event sequence inspection, having elucidated its purpose, key tasks and applicable technical means. Successively, the difficulty-to-solve points were analyzed with the case, thereby having them unwrapped into the specific inspection procedure from their examination feasibility assessment and planning, content inspection, scenario verification, Objective statement, logical judgment to the Results evaluation so that a sound expertise opinion could hence have been drawn. Finally, discussions were carried out on the present standards/norms about their improvement, together with the application of reverse thinking in the examination of relevant cases.

Objective To establish a rapid analytical method for determination of 1-(4-methoxyphenyl)piperazine (MeOPP) in whole blood based on liquid chromatography-triple quadrupole/linear ion trap tandem mass spectrometry (LC-QTrap-MS/MS). Methods The blood samples were treated with acetonitrile under oscillation, afterwards centrifugalized to precipitate the offal, with the supernatant being received as the analyte that was subjected to LC-QTrap-MS/MS analysis. LC was conducted within 5.5min via a Phenomenex Kinetx^®5.0μm Biphenyl 100Å (100mm×2.1mm) column that was kept at 40℃ of oven temperature and flowed at 0.5mL/min with a gradient elution of the mobile phase consisting of 0.1% formic acid aqueous solution - acetonitrile. The multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) scanning was adopted for determination of the analyte. 1-(4-methoxyphenyl)piperazine harbored in whole blood was quantitatively detected against its calibration curve. Results 1-(4-methoxyphenyl)piperazine, spiked in human blood samples, showed good linearity from its calibration curve over the concentration range from 2~200ng/mL under the optimized MS-MS conditions, having a maximal correlation coefficient of 0.9984 and the extraction recoveries achieved up to 87%, plus the intra- and inter-day relative standard deviations (RSDs) lower than 5% and 10%, respectively. In addition, its limit of detection (LOD) and limit of quantification (LOQ) were individually 0.8ng/mL and 2ng/mL. Conclusions LC-QTrap-MS/MS, assisted with MRM-IDA-EPI mode, can retain the same sensitivity as MRM's for quantification, yet having more abundant information provided about secondary fragment ions so as to make the qualitative Results more accurate. The here-developed method is simple, fast, accurate, specific, high of recovery rate and good of reproducibility, suitable for simultaneous qualitative and quantitative analysis of 1-(4- methoxyphenyl) piperazine in blood samples.

Objective To explore with retrospective statistical analysis into the problems that should be paid of attention in diatom detection through digesting organic matter with nitric acid. Methods Evidential materials of 484 cases for diatom test received from 2015 to 2020 were collected, with their harboring diatom in lung, liver, kidney, bone marrow and the controlling water samples being examined by nitric acid method (GA/T-813-2008). The resultant data were statistically analyzed. Results There were respectively 99.16%, 75.52%, 73.96% and 50% detection rates of diatoms in lung, liver, kidney and bone marrow. The aggregate positive rate of diatoms in liver and/or kidney accounted for 89.08%. The majority of diatom observed under microscope from the slide of smearing extra-pulmonary tissue fell among 1~10plus, with about 62.13% hepatic or 62.71% renal tissues being detected of 1~5 diatoms/20g. Conclusion The number of diatoms detected from the extra-pulmonary tissue is generally less than expectation when GA/T-813-2008 method is the adoption. Positive should be admitted if several diatoms are detected without possibility of pollution, requesting that at least two extra-pulmonary tissues should be extracted for the diatom test to improve its detecting rate and that the double check verification had better be strictly implemented to avoid false negative.

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.

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.

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.

Sexual asphyxia is a special mechanical suffocation. The doer of such a behavior generally has unusual or abnormal psychology, eager to pursue special sexual experience/sensation with personal steering of certain devices, means or substantive objects to strengthen sexual stimulation and pleasure. Deaths were therewith likely caused from excessive or wrong controlling during these ill acts. Sexual asphyxia performers mostly adopt the way of hanging although there are other peculiar manners. Adult males are mainly the doers of the ill performance, often naked or wearing female clothes. There are pornographic letters, pictures, images, decorations and appliances frequently found of being left on the scene. The nature of death is primarily by accident and sudden death. Occasionally, murder occurred into sexual suffocation. With the collected 73 cases of death from sexual asphyxia, an analysis was here retrospectively carried out to summarize the main points of forensic identification about such cases, purposing to provide references for forensic examiners to deal with those abnormal deaths.

Drunk driving offends against China's criminal law which has been updated of its version since 2011, often bringing the offender into infliction of certain punishment and worries. With intent to avoid legal punishment, some suspects of such crime will ask or even force the police to abate/annul their criminal records and the relevant cases. Here, an analysis was put into eight typical litigation cases that involved with judicial controversy about drunk driving in Guiyang city in recent years, thereby having outlined the risks against law enforcement. Three junctures would likely arouse the law-enforcing risks: the investigation and extracting evidence on the scene of drunk driving traffic accident, the blood sampling, and the detection of blood alcohol concentration. For both implementing the law and reducing risks, four principal points were thus propounded: scrutinizing into the scene of traffic accident and thoroughly collecting evidence, strictly complying with the procedure of handling case, standardizing the process of judicial inspection/examination, improving the competence of making legal documents. Meanwhile, suggestions were made about the attentions to be paid and measurements necessary to amend. Therefore, references would be accordingly provided for standardizing into handling drunk driving cases and getting rid of law-enforcing risks.

Objective to confirm the structure of F-ketamine, a new phenyclohexidine derivative, through the analyses of ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF), nuclear magnetic resonance (NMR) and other technic approaches. Methods One seized white crystal was respectively analyzed with GC-MS, UPLC-QTOF, ¹H-NMR AND ¹³C-NMR so as to determine its contained main chemical and molecular formula. Results Through adoption of GC-MS, an unknown compound from the seized white crystal was detected to have shown its characteristic fragment ions at m/z 164.1, 193.1, 136.0 so that the involving possible cracking mechanism was therewith inferred. Further, UPLC-QTOF approach brought out the accurate mass amount of the unknown compound being 221.1285 and the characteristic isotopic peak clustering ions. In combination of the proton number being 16 from ¹H-NMR and attribution ascertainment plus the carbon type from ¹³C-NMR analysis, the unknown compound was determined of its molecular formula as C₁₃H₁₆FNO, therefore confirmed as F-ketamine. Conclusion The combinatorial application of GC-MS, UPLC-QTOF, ¹H-NMR and ¹³C-NMR is appropriate to test and determine the unknown new psychoactive substances.

Objective To develop an analytical method for simultaneous determination of seven rodenticides (TETS, fluoroacetic acid, bromadiolone, brodifacoum, warfarin, coumatetralyl and flocoumafen) (categorized into 4 major kinds) in whole blood through ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). Methods The samples were treated with acetonitrile to precipitate protein, successively extracted through purification of PLD+ polymer column or organic microporous filter membrane. Luna Omega PS C18 chromatographic column (2.1mm×100mm, 3µm) was adopted for chromatographic separation with gradient elution. The analytes were detected under the mode of negative-ion ESI in full MS/ddMS². Results Detection limits (LODs) of the seven rodenticides varied among 10~50 ng/mL. The recoveries ranged from 85.3%~94.7% at three spiked levels in whole blood. The intra-day relative standard deviation (RSD) was 3.4%~11% (n=6), with the inter-day’s being 5.6%~13% (n=6). Conclusion This method is both qualitative and quantitative, capable of simultaneous and accurate screening of seven rodenticides in whole blood.

Objective To establish an LC-MS/MS method for determination of flualprazolam in blood. Methods Automatic rapid solvent extraction (ASE) was adopted to extract flualprazolam in blood. The extracted chemical was subjected to analysis of LC-MS/MS. Results Good linear relationship was present with peak area among 0.1~100ng/mL of flualprazolam in blood, with the involving limit of detection (LOD) being 0.05ng/mL, limit of quantification as 0.1ng/mL, and recoveries within the range of 75.4%~95.3%. Conclusion This method is of fast extraction speed, simple operation, low detection limit, high recovery rate and good reproducibility, therefore suitable for determination of flualprazolam in blood.

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.

Arson, a typical violent crime anywhere, usually results in heavy casualties, severe economic losses and adverse social impact. Therefore, it is urgent and necessay to have an optimal investigation mechanism and method to determine the nature of a suspected fire case swiftly and accurately. Nevertheless, the highly destructive sites and easily destroyed evidence frequently have the fire investigators met with great challenges. As one of the countries of occurrence to frequent arson cases, the United States has developed advanced investigation technologies about arson and its investigators have thus accumulated rich experience through tackling with large number of arsons. In order to provide meaningful suggestions for arson investigors to optimize their investigating and handling mechanism and strengthen on-site investigation technologies in China, the essay herein introduced the means and technologies applied about arson investigations by the concerned departments in the United States in recent years and summarized the key points that can be referential for the investigations to handle those similar arson cases in China. For arson cases, whether they are involvement with ignitable liquid or not, this article is purposed of further improving the scientificity and accuracy for investigation of arson cases in China from the perspectives of response mechanism, information gathering and physical evidence collection.

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.

Strong evidence can be provided for case investigation through accurate identification of body fluid stains at crime scene so that an importance will have been being attached to the relevant studies. miRNA has recently been becoming a research hotspot for body fluid identification with its merits of stability, specificity and rapidity of detection. qPCR (quantitative PCR) is the so-called gold standard for miRNA detection thanks to its high sensitivity and excellent specificity from the involving fluorescence-based quantitative real-time PCR. However, selection of appropriate reference genes is the prerequisite to obtain accurate and reliable results when relative quantification is the purpose. Accordingly, this article tries to make an overview about the selection of reference genes adopted for body fluids identification using miRNA detection, with the emphasis being put on the concerned research progress, selection methods and application challenges.