15 June 2016, Volume 41 Issue 3
    

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    Research Articles
  • An Investigation of DNA Transfer onto Forensic Evidence Package
    DONG Hui, WANG Jing, QIN Cuijiao, ZHANG Tao, JIA Jing, YE Jian, LI Caixia, LIU Chao
    Forensic Science And Technology. 2016, 41(3): 173-177. https://doi.org/10.16467/j.1008-3650.2016.03.001
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    Objective Biological evidential material, enclosed in forensic evidence package, may be transferred onto its package, making the DNA typing less detectable. Therefore, the lower transfer level is better, especially for the trace touch DNA samples. This study aimed to investigate whether the DNA is transferred onto forensic evidence package and the transfer rate between different types of evidential materials and packages. Methods With two kinds of forensic evidence package, the seal-lock plastic bag and yellow paper envelope, three kinds of trace touch DNA, four blood and saliva samples were prepared to simulate the packaging and transporting process. An individual, carrying a suitcase which contained all of the test samples, walked on a treadmill (running at 4 km/h) for 30 min, then went up- and down-stairs for five stories. DNA, extracted from the test samples and the evidence packages, was quantified, amplified and analyzed following the manufacturer’s standard procedures. The transfer rates were compared with two different packaging ways. Results The experiment showed that all of the test samples were transferred onto package at various levels and the average transfer rate was 22.06 %. The two types of packages were observed of significant difference (P=0.023) for their transfer rates, with those of the seal-lock plastic bag being estimated as 17.85 % and the yellow paper envelope as 26.27 %. The transfer rates of the trace touch samples were higher than those of the blood and saliva samples no matter whether they were kept in the yellow envelope or the seal-lock plastic bag. The loss of recoverable DNA from the samples to the evidence packages ranged from 1.84 % to 67.66 %. Conclusions DNA transfer occurs on the forensic evidence package to crop it, affecting DNA typing. Different types of samples have different transfer rates and so have the evidence packages.
  • Key Elements of Scene Investigation and Analysis for Bus Arson Case
    ZENG Linghua,FAN Wulong, SHI Yi, PAN Yanhui,WANG Mingzhi
    Forensic Science And Technology. 2016, 41(3): 178-182. https://doi.org/10.16467/j.1008-3650.2016.03.002
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    In recent years, bus arson cases tended to arise in China. However, most local public security organs lack the experience to investigate the scenes of these viciously violent crime cases, resulting in more serious problems when such cases suddenly happened in those relevant places. There are few home and abroad studies about how to specifically investigate and analyze a bus arson crime scene. This study aims to provide a reference for the public security and inspire authorities to enact the work regulation on investigating and analyzing the scene of bus arson case scientifically and standardizedly. Crime scene investigation and analysis are an understanding and practical process which can expose the manner and behavior of the criminal by logical reasoning and practical verification upon the scrutiny of entire scene, and it is the basis for evidence collection and scene reconstruction. Based upon a series of bus arson cases and bus burning accidents occurred in China in recent years, this study focused on the scene investigation and analysis of bus arson. Various bus arson cases’ similarities and differences were analyzed by comparison with other 16 bus burning accidents happened in China, with purpose to sort out the basic elements of crime scenes components and related information of these bus arson cases. From 10 typical major cases, a summarization was attained about the important and necessary information or characteristics for crime scene investigation and analysis. In combination of the current experience of crime scene investigation and analysis with the characteristics of bus arson cases, key elements and measures were put forward for this kind of scenes’ analysis, which can also be comprehensively supported by today’s main technologies in scene investigation like evidence examination and tracing, video and electronic forensics, fire scene investigation, crime scene analysis and reconstruction. Generally, the investigation and analysis on bus arson case scene can be carried out in 4 steps: scene investigation, evidence collection and identification, evidence classification and comprehensive judgments where the difficulties investigators have to face must be taken into thorough and all-around account.
  • Analysis of Expert Testimonial Opinions Quoted in Judgment Documents
    BAO Liyin, GE Yunying, JIN Yifeng, CUI Bin, AI Kangyun
    Forensic Science And Technology. 2016, 41(3): 183-188. https://doi.org/10.16467/j.1008-3650.2016.03.003
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    At present, almost all of the judgment documents have been open to the public because the Supreme People’s Court of China required that such documents be published online from January 1, 2014. Therefore, the intuitive survey is since capable of attaining the application of evidence in the form of expert testimony during the judicial processes. Institute of Forensic Science, Ministry of Public Security, People’s Republic of China (CIFS), one of the largest judicial forensic institutions in China, issues thousands of expert testimonial opinions every year. This paper analyzed 495 online judgment documents where the CIFS’ expert testimonial opinions were cited in the relevant criminal, civil and/or administrative cases,discussing the adoption of these expert testimonial opinions, their related professional fields, the involved case details and in addition the trial levels. From this analysis, CIFS, a judicial forensic institution standing for China Public Security, has also been showed its status and role in the current judicial activities at Chinese courts of all levels.
  • The Remaining Characteristics of Body Odor Left on Different Material Surfaces
    LONG Chengsheng, WANG Xin, WU Dehua, SONG Zhenhua, QIANG Jingning
    Forensic Science And Technology. 2016, 41(3): 189-191. https://doi.org/10.16467/j.1008-3650.2016.03.004
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    Objective The odor from different people is very useful for prevention and fighting against crime, especially when canines are used to discriminate it. In order to support the crime scene investigation, we have explored the remaining characteristics of human body odor left on different material surfaces including marble, wood, cotton and clay. Methods A homemade wind tunnel was used to model the environmental factors in the crime scene. These factors include temperature, wind speed and moisture, being respectively set to 20 ℃, 1.6 m/s and 35 %. GC/MS was used for the detection of remaining characteristics of the body odor that is indicated by five marker compounds: dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid and hexadecanoic acid. The temperature for MSD transfer line was set at 280 ℃. The temperature for ion source and quadrupole was set at 230 ℃ and 150 ℃, respectively. Electron ionization mode was used at 70 eV with a scanning rate of 3scans/s over the mass range of m/z 30-350 amu. The samples were collected by them (marble, wood, clay, or cotton) being grabbed or pressed with hand. Seven samples in a group of the same people, were used to test the variance of odor concentration during 24 hours on the same sampling object. Solid Phase Micro-Extraction kit was used to extract each sampling object every four hours. In data processing, the 0 hour’s sample was the reference, whose concentration was assigned to 100% to normalize the other samples’. Results The odor concentration on different material surfaces decreased with time elapsing. The concentrations of body odor adsorbed onto the surface of marble, wood, clay and cotton were as many of 30 %, 34 %, 57 % and 63 % as the initial concentrations. After 24 hours, the remaining odor on marble, wood, clay and cotton were left of 12 %, 16 %, 30 % and 35 %, respectively. The result demonstrated that at the same environment conditions, the odor adsorption capacity of the cotton was better than that of marble, wood, and/or clay. Conclusion In crime scene investigations, the odor samples from the wood, cotton and/or clay were greater than that from marble.
  • Comparison of Disability Degree Evaluated with Two Disability Assessment Standards
    JIAO Yuwen
    Forensic Science And Technology. 2016, 41(3): 192-194. https://doi.org/10.16467/j.1008-3650.2016.03.005
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    Objective For the same injured people to be respectively evaluated by “Assessment for body impairment of the injured in road traffic accident” (GB18667-2002) and “Standard for identifying work ability: Gradation of disability caused by work-related injuries and occupation diseases” (GB/T 16180-2006), their disability degrees were compared to ascertain whether there exists difference in the Results obtained from the two appraisals. Methods 1036 cases of adults, whose limb long bones suffered from fractures caused by traffic accidents, were collected, these cases happened from 2007 to 2013. With the evaluation by the above standards, the disability degree was obtained and compared along with the number of fractures, treatment situation and physical dysfunctions. Results Only 17 cases (1.64 %), where the people still remained limb dysfunctions although having received the external fixation after being fractured, are basically of the same disability degree, but the others have greater differences. Conclusion There are somewhere greater differences to evaluate the disability degree with the respective application of the two standards above.
  • Mutual Influence to Develop Fingerprint by Heat-induced Fluorescence and Traditional Handling
    LI Xiaojun, WU Hao, WANG Jinzhong, XU Wei
    Forensic Science And Technology. 2016, 41(3): 195-199. https://doi.org/10.16467/j.1008-3650.2016.03.006
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    Objective To study the mutual influence between the Methods to develop fingerprint by thermal induced fluorescence and the traditional handling with substances such as ninhydrin, silver nitrate, DFO and Indandione, by ascertaining whether the fingerprint developed with thermal induced fluorescence is enhanced by the successively traditional treatment, and vice versa, the handling of thermal induced fluorescence can improve the fingerprint development by the traditional method. Methods With the optimum TFD-2 conditions, the effect and identifiability was compared upon the on-paper fingerprint developed by the thermal induced fluorescence and traditional disposal. Results The experimental Results show that the method of thermal induced fluorescence does not affect the follow-up traditional handling for the fingerprint development, but even enhance the developing effect to some extent, whereas the traditional Methods can variously influence the effect gained with the thermal induced fluorescence. The above experimental phenomena may suggest that this method can be incorporated into the development of fingerprint on porous objects. Conclusion The method of thermal induced fluorescence can be used to pretreat the latent fingerprints on common paper before traditional Methods, with advantages of simple operation, quick development, high sensitivity, wide scope of application, and more effectiveness for old fingerprint.
  • Using the Modified Al2O3 Nanoparticles Suspension to Develop Latent Fingerprint
    ZHANG Limei, ZHANG Dongdong, ZHANG Zhongliang, WANG Shuai, SUN Nianfeng
    Forensic Science And Technology. 2016, 41(3): 200-202. https://doi.org/10.16467/j.1008-3650.2016.03.007
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    Objective Using the silane-coupling-agent-modified nanosized particles of di-aluminum trioxide (Al2O3) for developing latent fingerprint. Methods Al2O3 nanoparticles were modified with a silane coupling agent. The change of the surface functional groups of the nanosized Al2O3 particles was measured by Fourier transform infrared absorption spectrum (FT-IR). The developed latent fingerprints on ceramic, glass, aluminum foil, plastic, algam were obtained by the modified Al2O3 nanoparticles and evaluated, together with their comparison of the Results acquired through the silane-coupling-agent-modified Al2O3 nanoparticles against those got from the surfactant-modified Al2O3 nanoparticles. Results The silane-coupling-agent-modified Al2O3 nanoparticles exist the characteristic absorption peak of silane coupling agent at 1638, 2853, 2921 and 3302 cm-1 in the Fourier transform infrared absorption spectrum (FT-IR), showing a better fingerprint-developing performance than that of the original Al2O3 particles. Conclusions The suspension of silane-coupling-agent-modified Al2O3 nanoparticles is stable, suitable for practical application into the latent fingerprint development.
  • Analysis of Handwriting from Black Roller and Gel Ink Pen by Surface-enhanced Raman Spectroscopy Based on Gold Colloid
    CHEN Ning, LI Shuying, ZHANG Xiaoxia
    Forensic Science And Technology. 2016, 41(3): 203-205. https://doi.org/10.16467/j.1008-3650.2016.03.008
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    Surface-Enhanced Raman Spectroscopy (SERS) is a technique that extends the range of Raman applications to trace analysis. SERS has considerable benefits in the identification of forensic evidence, as it can quench fluorescence and provide significant differences, including peaks of different heights, shapes and shifting, together with the new peaks. This study presents a new method for the minimally invasive in situ analysis of handwriting from black roller and gel ink pen by the SERS based on concentrated gold colloid. Ninety brands of black roller and gel ink pens were collected to make their own handwriting samples on paper. The concentrated gold colloid was dropped onto the handwriting strokes, then the prepared samples were analyzed by DXR Raman microscope. All the SERS spectra were gathered under the same collection parameters of 780nm laser, 0.1mW laser power at sample, 10X Objective of microscope, and dark-field illumination. The SERS spectrums of handwritings written by the 90 brands of black roller and gel ink pens can be classified into six kinds. SERS, based on gold colloid, is a powerful technique for the examiner to rapidly analyze the handwriting from black roller and gel ink pen, demonstrating suggestive for comparative examination of these handwritings.
  • Analysis of α-Bromopropiophenone
    GUO Jian, LIN Xiaolong, WU Shengwu, LIU Xiangwei, ZHOU Yuzhuo
    Forensic Science And Technology. 2016, 41(3): 206-208. https://doi.org/10.16467/j.1008-3650.2016.03.009
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    Objective Alfa-Bromopropiophenone, often used to synthesize ephedrine, has been listed and controlled as the first category of precursor chemicals by the State since May 12, 2014. Therefore, the characteristics and hazardousness involving in ephedrine manufacturing with α-Bromopropiophenone should be studied. As such, the analysis procedure of α-Bromopropiophenone has been established in this paper. Methods The optimal parameters for α-Bromopropiophenone analysis were developed with FTIR, GC/MS and GC/FID. Results Alfa-Bromopropiophenone (tR=5.064min) presented its characteristic fragmental ion peaks at m/z 105.0(base peak), m/z 77.2 and m/z 51.2. A possible mass spectrogram of α-Bromopropiophenone was given. The infrared absorption spectra were shown in 3060, 2980, 2860, 1690, 1340, 1240, 1160, 1080, 1590, 1450, 843, 706, 542 and 646 cm-1. Under the optimal conditions, a good linearity was observed for α-Bromopropiophenone in 0.01-0.50mg/mL and the correlation coefficient was 0.9997. The LOD (S/N=3) was 0.2 μg/mL. The RSD was 1.59 % for 0.1mg/mL of α-Bromopropiophenone (n=6).Conclusion The method developed here is simple, sensitive and reproducible with its successful application into the qualitative and quantitative analysis of α-Bromopropiophenone.
    • Reviews
  • An Introduction to Evaluation of Physicochemical Data for Forensic Purposes with Application of Likelihood Ratio Test
    ZADORA Grzegorz, MARTYNA Agnieszka, MICHALSKA Aleksandra, WŁASIUK Patryk
    Forensic Science And Technology. 2016, 41(3): 209-220. https://doi.org/10.16467/j.1008-3650.2016.03.010
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    The increasing complexity from new forms of crime and the need by those who administer justice for higher standards of scientific work require the development of new approaches for measuring the evidential value of physicochemical data obtained by application of numerous analytical Methods during the analysis of various kinds of trace evidence. The Methods used for evaluation of these data should reveal the role of the forensic experts in the administration of justice. This means that such data (evidence) should be evaluated in the context of two competing propositions H1 and H2 formulated by two opposite sides in the legal proceeding, i.e. prosecution and defence. Bayesian models have been proposed for the evaluation of evidence in such contexts. This paper describes the principle of likelihood ratio (LR) approach for evaluation of physicochemical data in so-called comparison and classification (in fact, classification is also based on comparison) problems. The LR models allow including all of important factors in one calculation run where evidential value of physicochemical data is to evaluate. These factors are the similarity of observed physicochemical data in compared samples, the rarity of determined physicochemical data in relevant population, and the possible sources of errors (within- and inter-sample variability). The LR models, as statistical tools, can be only proposed for databases described by a few variables. However, most of physicochemical data are highly dimensional data (e.g. spectra). Therefore, it is necessary to apply Methods of dimensionality reduction like graphical models or suitable chemometrics’ tools, with examples presented in the paper. The LR models should be always treated as a supportive (not the decisive!) tool and their Results subjected to critical analysis. In other words, the statistical Methods do not deliver the absolute truth as the levels of possible false answers are an integral part of these Methods, in the same way like uncertainty related to the applied analytical techniques. Therefore, sensitivity convergence, an equivalent of the validation process for analytical Methods, should be conducted in order to determine their performance. Thus, how to validate LR models is addressed in this paper by the example of application of Empirical Cross Entropy approach. There is the so-called source-level evaluation for physicochemical data as it helps to answer the question whether the compared samples are originated from the same object. Usually, the fact finders (judge, prosecutor, or police) are interested in recognizing the activity that made transferred and persisted of the recovered microtraces (which reveal similarity to control sample) from body, clothes or shoes. This is the so-called activity-level analysis, also discussed in the paper.
  • Progress in Imaging the Age-related Changes of Dental Pulp Cavity
    LÜ Tu, HE Guanglong, WANG Jian
    Forensic Science And Technology. 2016, 41(3): 221-224. https://doi.org/10.16467/j.1008-3650.2016.03.011
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    The structural and functional changes related to chronological age can be observed in human tissues and organs. Researches of these physiological appearances depend on innovations of the scientific instruments and technologies. Tooth is the hardest organs of human body. One tooth is commonly composed of its crown, cervix and root. From the outside to the inside, it contains three hard and one soft tissue, which are consecutively the enamel, the cementum, the dentin and the dental pulp. The age-related changes of the tooth are usually involved with three kinds of parameters: the formative, the degenerative and the histological. The formative parameters include tooth mineralization, crown completion, eruption of the crown, among others. Degenerative measurements include tooth wear, tooth color and periodontal attachments. Histological assessments include the degree of secondary dentin deposition, root resorption, inter alia. Compared with other parts of the tooth, the pulp cavity reveals more forensic values due to its age-related changes. The 3D imaging used in the dentomaxillofacial medicine has brought new Methods for studying the age-related changes of pulp cavity, through its advantages of high image resolution, rapid scanning, low radiation and simple operation. The 3D imaging researches on the dental pulp cavity changes along with age may supply a new approach to estimate the ages of old people and/or destroyed skeletons. Age estimation, based on anthropometric and morphological observation, reveals the regularity of age-related biological changes. To improve the accuracy of the estimated age, multiple indicators should be calculated. With addition of the pubic symphysis surface, the tooth wear and the epiphyseal union, the 3D image of pulp cavity will play more important role in crime investigation and disaster victim identification.
  • Research Progress on Age Estimation of Fingermarks by the Components Analysis
    SUN Jing, FAN Li
    Forensic Science And Technology. 2016, 41(3): 225-228. https://doi.org/10.16467/j.1008-3650.2016.03.012
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    Age estimation of fingermarks could have a significant impact on forensic investigation, as this has the potential to facilitate the judicial process by assessing the relevance of a fingerprint found at a crime scene. Determination of the time since deposition of fingermarks may prove necessary to link their pertinence with certain criminals. However, no Methods currently exist that can reliably predict the age of a latent fingerprint because various factors, such as different bequeathers, diverse carriers, changing environment, can affect the age estimation of fingerpmarks. With the development of the sensitive instruments and devices, researchers have tried many approaches to solve the problems. Some have pointed out that by the ratio of the target component’s content degrading over time divided by the summed of more stable compounds (which are less variable from print to print) in fingerprint residues, the time when a fingerprint was deposited can be inferred. Some used time-of-flight secondary ion imaging mass spectrometry (TOF-SIMS) to measure the diffusivity of saturated fatty acid molecules from a fingerprint on a silicon wafer, showing that a fingerprint less than 4 days could reliably be deduced through the extent of diffusion of palmitic acid. Some tried to use fluorescence spectroscopy to measure the rate of proteins degradation and the rate of oxidated products’ generation in aging fingermarks. This article attempts to introduce the research progress on age estimation of fingermarks by the relevant components analysis.
    • Forum
  • About On-site Quick Detection of TATP
    ZHANG Jifeng, FAN Wulong, SUN Yuyou, ZHAO Xiaohui, LIU Jiping
    Forensic Science And Technology. 2016, 41(3): 229-231. https://doi.org/10.16467/j.1008-3650.2016.03.013
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    The quick qualitative test of triacetonetriperoxide (TATP) is one of the main means to effectively control and prevent the crime involving TATP or such kind of explosives. The on-site quick detection of TATP was deep analyzed and discussed in this paper, with its principle and equipment being introduced. Several detection experiments of TATP explosives were carried out, together with the Methods, features and effects to be verified and quested. This investigation can be a basis for effectively controlling and combating the crime involving TATP.
  • Detection of Latent Fingerprint on Paper Using 1,2-Indanedione-based Bi-functional Reagent
    SHA Wanzhong, FANG Yao
    Forensic Science And Technology. 2016, 41(3): 232-235. https://doi.org/10.16467/j.1008-3650.2016.03.014
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    Latent fingermarks, often found at crime scenes, are the most common and problematic types of evidence as they require developing ways to be seen and recorded. Fingerprint visualization is vitally important in forensic science. Today, visualization of sweat latent fingerprint by chemical approaches is one of the most sensitive Methods, able to be applied on porous and non-porous surfaces, such as paper, plastic, printed materials, wood products and others. Since modern society is heavily dependent on such materials as official documents, written messages, currency printing, magazines and packaging, the detection of hidden fingerprint on paper and other related cellulosic materials is considerably important by the chemical techniques. Because almost all the new chemical Methods to develop fingerprint are based on the detection of amino acids that are present in natural skin secretions, and the amino acids are to bind onto the cellulose of the paper when a sweat fingerprint is deposited on certain paper material, leaving either a visible or invisible impression of the fingerprint ridges, therefore, fingerprint can be observed on paper substrate by the main chemical Methods, generally including those of silver nitrate, ninhydrin, DFO and silver physical developer. But these Methods still have some deficiencies, like considerable magnitude of latent fingerprints withal difficult to detect. A novel 1,2-indanedione-based bi-functional reagent has been designed for the development of latent fingerprints on paper substrate. The reagent was synthesized through a concise five-step protocol and modified multi-metal deposition (MMD) process. Positive images of latent fingerprints will be developed by the reagent’s preferential binding to the fingerprint ridges. Fingerprints that contain both amino acids as well as oily substances can be successfully detected via the reagent’s elevated developing efficiency.
  • Preliminary Study on Specific Features of Embossing Seal’s Imprints
    WANG Xiaoguang, LI Mengmeng, QIN Da, YAN Haiqian, HAN Xingzhou, GUO Zihan, HAO Honggunag
    Forensic Science And Technology. 2016, 41(3): 236-239. https://doi.org/10.16467/j.1008-3650.2016.03.015
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    Embossing seals are widely used on many kinds of documents, such as diplomas, notarization documents and commission letters. Actually, embossing seals can secure authenticity and prevent from counterfeiting. The examination of embossing seal is an important part of the seal’s. Imprints by embossing seals can make the structure of paper changed and both-sided three-dimensional feature formed. Moreover, both sides of the embossed imprint can reflect the seal’s surface features. Such imprints, shown with three-dimensional and colorless feature, are difficult to track record although both of the two sides can tell the features of the involved seals, revealing their own specific features and rules for examination. At present, the studies about the embossing seal’s imprints are less, especially for the specific features of them. Therefore, it is very important and crucial to conduct the research on the aspect. Due to lack of reference, the documents examiner can only get resorts to ordinary seal’s research theory and practice. As such, this study perhaps is the very priority of its kind. The authors here describe the forming process of embossing seal, classify the specific features of such seal’s imprint into five styles: the side-wall marker, three-dimensional angle, transparency, edge pattern and attachment of metal-oxide particles. Meanwhile, the distinguishing peculiarity and influential factors of these specific features are manifested. Attentions are put forward to be paid in examining the embossing seal and its imprints.
    • Technical Notes
  • Method to Fast Dispose Mass Electronic-evidence Data for Counterfeit Currency Tracing
    ZOU Jixin, LI Shifeng, YU Jian, QI Fengliang, LIU Guanhua
    Forensic Science And Technology. 2016, 41(3): 240-243. https://doi.org/10.16467/j.1008-3650.2016.03.016
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    Objective Counterfeit currency crimes tend to a growing trend. Although the large denomination of RMB is primarily the imitated target, the small ones of it have become increasingly arising, too. Because of the simple operation, low cost, concealment, print of quality and other characteristics, color printers or other digital printing equipment are the preferential choice for the criminals to fabricate the counterfeit currency. Therefore, the relational electronic version of the printed counterfeit money is the key clue to fight against counterfeit currency crimes. This paper attampts to establish a fast method to discover the valuable information from mass electronic-evidential data for counterfeit currency tracing. Methods With special equipment, the data were collected from cell phones, laptops, PCs, USB flash drives and other devices that were used to fake genuine currency by the suspects. The hash value, drawn from the above collected data, was calculated. A computer program was devised to find out the duplicate data of same hash value and merge into a file cluster. Through analyzing the screened file cluster, the source of electronic version of counterfeit currency was to trace back. Results The source of electronic version of counterfeit currency can be quickly tracked through picking out the key information and eliminating the useless one from the enormous electronic files. With the established method here, a specially momentous case has been given the crucial clue by exhumation of the source of evidence from different suspects. Conclusion The method to get hash value by fast disposing a large amount of electronic evidential data is of high efficiency and swift speed for analyzing the source of counterfeit currency.
  • Genetic Polymorphism of 41 STR Loci of Guangdong Population
    TANG Zhenya, LI Haiyan, CHEN Hongying, ZHAO Kai, KUANG Yubin, NING Zhong
    Forensic Science And Technology. 2016, 41(3): 244-246. https://doi.org/10.16467/j.1008-3650.2016.03.017
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    Objective To study the genetic polymorphism and frequencies of 41 short tandem repeats (STRs) loci in Guangdong population. Methods Allele frequencies of 41 STR loci were obtained from 500 unrelated individuals of Guangdong population using the routinely laboratory-used DNA analytic techniques. The genetic polymorphism and frequencies were statistically calculated. Results The combined discrimination power (CDP) was 1-1.0755×10-45. The cumulative probability of exclusion (CPE) was 1-1.9895×10-17. Conclusion Combined application of 41 STR loci into individual identification as well as paternity testing would be highly efficient, especially for the paternity testing of duos or missing children.
  • An Example of Examining the Shotshell Marks
    LOU Yan, CHEN Liuyi
    Forensic Science And Technology. 2016, 41(3): 247-250. https://doi.org/10.16467/j.1008-3650.2016.03.018
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    Frequently, the firing pin marks may be distorted, bulged, cracked or penetrated due to the pressure from the anvil and the gas of gunpowder. This may cause damage to the reproducibility of firing pin marks in different degrees, and may cause greater uncertainty to the examination and even misguide to a false judgment on the marks. In the case reported here, two shells from crime scene were collected and two types of suspected shotguns were recovered (one is a pump shotgun and another is a double-barrel (up and under one) shotgun). By comparison of the marks on bottom and edge parts of the firing pin and those on the breech face, a conclusion was made that one shell was fired from the pump shotgun and the other from the double-barrel one. Specially, the scratch marks on the edge of the firing pin impression were introduced onto the shell that was fired from the up barrel of the double-barrel shotgun during the process of the firing pin tilting against the primer. These scratch marks are primary marks, different from the drag marks by the firing pin. With the scratch marks, not only can the type of shooting gun and even the barrel (up or under) be distinguished but the firearms can be identified as well.
  • Analysis of the Molten Plastic Balls in a Hit-and-run Case
    SUN Zhenwen, WANG Hu, QIAO Ting, LIU Zhanfang, TAO Keming, ZHU Jun
    Forensic Science And Technology. 2016, 41(3): 251-253. https://doi.org/10.16467/j.1008-3650.2016.03.019
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    Plastic is an important kind of evidence in hit-and-run accidents. Transfer of plastic substance occurs frequently in the striking process between the involved vehicles. Plastic samples, collected from vehicles involving in hit-and-run accidents and other investigated vehicles, are routinely examined and compared in present forensic laboratories. Fourier Transform Infrared Spectroscopy (FT-IR) is the most frequently used method for plastic analysis. Polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and acrylonitrile butadiene styrene (ABS) are the most commonly used polymers of vehicles. Some plasticizers and inorganic fillers, added into the plastic, can also be analyzed by FT-IR. This paper introduced an examination of smeared plastic sample collected from the suspected truck and the known plastic sample from the handlebar of involved motorcycle. The main component of the plastic sample from the suspected truck is PVC with calcium carbonate as the filler and a small amount of dimethyl-phthalate as the plasticizer. In order to avoid destroying the scratched mark, the compared sample was collected near the scratched mark of the handlebar of the involved motorcycle. By FT-IR analysis, the compared sample showed stronger bands than the plastic smears from the suspected truck at 744, 1074,1125,1287 and 1726 cm-1 which were assigned to dimethyl-phthalate. The Results indicated that the sample contained more plasticizer. It is necessary to perform further examination since high temperature in the friction process may affect the component of PVC plastic. Under the stereomicroscope, we found molten plastic balls on the position of the scratched mark of the motorcycle’s handlebar. However, there was no difference found by the FT-IR method between the molten balls and the plastic smears of the suspected truck. Nevertheless, the SEM/EDS elemental analysis showed the plastic smears on the suspected truck was much likely to come from the involved motorcycle. Thus, it can be concluded that the weak FT-IR spectra of PVC from the plastic smear were caused by the decreased amount of PVC transferred in the friction between the suspected truck and the motorcycle. In conclusion, it is important to consider the influence of high temperature on the compared sample together with careful selection of appropriate collection places. Only can sample collection be directly performed on the position of the scratched mark when not damaging the mark characteristics and/or its inspection.
  • Identification of Genus by Trace DNA of Poppy Slurry
    ZHU Dian, PEI Li, ZHANG Ying, XU Xiaoyu, Yang Xueying
    Forensic Science And Technology. 2016, 41(3): 254-256. https://doi.org/10.16467/j.1008-3650.2016.03.020
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    Objective Current genus identificaiton of poppy in drug cases, is achieved mostly through the DNA testing of the plant’s parts, such as the leaf, seed, root and stalk, which contain large amounts of DNA. Poppy slurry is not a good sample for such kind of DNA testing as it contains only a small amount of DNA. The aim of this study is to explore the method of poppy genus identification through DNA testing of poppy serous fluid and similar samples.Methods The suspected poppy slurry was disposed to obtain its suspension that was further centrifugated to separate into the supernatant and sediment. The sediment was dried and grinded into powder. From the suspension, supernatant and powdered sediment, DNA was respectively extracted and purified by using the magnetic beads method. PCR amplification was carried out with poppy specific fluorescent primers (P14) under optimized conditions, and the amplification Results were detected by gel electrophoresis. Finally, the genus identification was achieved by comparing the Results with a known poppy control sequence. Results Two specific DNA fragments were clearly identified from the sediment group, and the peak values of specific bands increased with PCR cycle number ascending.Conclusio nThe genus of poppy slurry can be identified through its DNA testing, and the result shows a practical value in drug related cases, suggesting a new choice for the genus determination of toxic plant by testing the DNA of its slurry.
  • STR Genotyping of the Embryonic Villi Tissue Fixed with Formalin
    ZHANG Yongguo, HOU Weiguang
    Forensic Science And Technology. 2016, 41(3): 257-258. https://doi.org/10.16467/j.1008-3650.2016.03.021
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    Formalin-fixed embryonic tissue, excised from tubal pregnancy, was tested after it had been kept in such fixed condition for two months. Two aliquots of the above sample were taken out, being digested of one piece with or without urea addition. DNA was extracted with Maxwell™ 16 auto-equipment, in succession of its concentration being measured by Quantifiler Kit. The genotype was determined by ABI3130xl after the extracted DNA had been undergone the multiplex amplification by PowerPlex 21. The biological father of the embryo was ascertained through comparison with the suspect’s DNA. Based on the case and its successful settlement, a discussion was put upon the DNA extraction and STR test when the sample was badly putrefied out of formalin fixation.

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