In forensic science, the interpretation of DNA mixture profiles and small amounts or degraded DNA profiles is challenging due to difficulties in evaluating the contribution of the person of interest (e.g., victim and suspect). In recent years, some probabilistic genotyping software programs based on a continuous model were developed to promote the interpretation of complex DNA profiles. The model uses quantitative information of peak heights in the DNA profile and considers the effect of stutters and allelic drop-out. Therefore, the model is effective for interpreting complex DNA profiles, and some software based on the model that has been applied to actual caseworks.

 This review provides the concept of probabilistic genotyping based on a continuous model. We explain calculation principles of likelihood ratios, weight values, and expected peak heights in the continuous model. We also discuss the current issues of software validation, management of artifact peaks, and the estimation of the number of contributors.

　The behavior of degradation and diffusion of phosphorus-containing amino acids, glyphosate and glufosinate, in soil was investigated over a long term of up to 6 months. The herbicides were extracted from the soil under strong alkaline condition and quantified by liquid chromatography-tandem mass spectrometry. Diffusion and downward penetration were hardly observed for glyphosate, and was observed for about 90 days in summer and about 185 days in winter. For glufosinate, on the other hand, the observation was relatively short at about 10 days, and diffusion and penetration in soil were slightly observed. In the case when glyphosate or glufosinate is dumped on the ground for criminal purposes, the herbicides could be detected at least for 6 months for glyphosate and 1 month for glufosinate from the surface soil by using the method presented in this paper.

 Discrimination between allele peaks and stutter peaks is important in STR typing for forensic purposes. In minus stutter, it is known that there are correlations between alleles and stutter ratios, but there are few reports on other types of stutter such as plus stutter. In this study, we examined the relationship of alleles to stutter ratios in Y-STR typing using the Yfiler^TM Plus PCR Amplification Kit. DNA was extracted from blood samples collected from Japanese males and multiplex PCR amplification was performed with 1 ng DNA template. In minus stutter, high correlation coefficients (r>0.7) between alleles and stutter ratios were observed in 23 of 25 markers. Meanwhile, in other types of stutter, only the forward stutter in DYS392 showed such a high correlation coefficient. These results can be used for interpretation of electropherogram data in forensic Y-STR typing.

　Image enhancement of a pre-processed and colored fingerprint with complex background patterns has high demand in appraisal evaluation of forensic evidence. This paper focuses on image enhancement of ninhydrin-processed fingerprints on periodic-patterned backgrounds. Contrast adjustment usually does not work well for separation between fingerprints and periodic-patterned backgrounds because of similarity in their color scales and/or superposing patterns. As alternative methods of contrast adjustment, two approaches have been proposed. The first one is to transform an RGB evidence image to a CIELAB color space and to utilize hue so that the hue of pixels is converted to a sharp contrast of brightness. The second approach is to conduct Principal Component Analysis (PCA) on an evidence image in RGB and CIELAB color space and to reconstruct PC images. This approach is effective for a case that the hue-based image processing is not sufficient to enhance fingerprints. Moreover, this method can be successful in CIELAB in enhancing a fingerprint which is not able to be enhanced in RGB. It is also suggested that fingerprints and backgrounds in complementary color can be separated. For certain RGB evidence images, the hue-based approach and the PCA-based approach achieve more enhanced fingerprints than the contrast adjustment does. If some periodic patterns remain after the processing of each approach, these patterns can be removed by using frequency filtering based on 2-dimensional Fast Fourier Transformation. It is effective to apply the hue-based approach first and, if the enhancement of fingerprints is not sufficient, then it is recommended to use the PCA-based approach both in RGB and CIELAB color space. Proposed methods are easy to be conducted when an RGB image including a colored fingerprint is given by a common digital camera or flatbed scanner. Our methods can also be used even when an image for background subtraction is not available. Proposed methods expand the capability of utilizing colored fingerprints processed by ninhydrin for the forensic evidence.

 A time interval-sliding (TIS) method was developed for analysis of respiratory measures such as respiratory line length (RLL) and weighted average (WA) that are used in concealed information tests (CIT). The validity of this method was tested using simulations. The TIS method shifts the time interval such that its starting point for an analysis shifts to the bottom of the respiratory cycle. In study 1, it was demonstrated that negative influences on RLL and WA caused by a starting point of analysis could be solved using the TIS method. In study 2, the efficacy of the TIS method was tested using CIT simulations. The results of these two studies indicated that the TIS method improves discriminability of RLL and WA. It was also found that the discriminability of the RLL was improved to the same level as those of the WA, although the RLL values were lower than those of the WA prior to operating the TIS method. Therefore, it can be expected that the TIS method will be an effective technique for the analysis of respiratory measures of CIT.

 Biological evidence is often found at crime scenes that are from human and various unknown organisms. In some cases, species identification is important for an investigation. Therefore, a direct sequencing method that targets three regions of the 16s rRNA gene was examined to classify 14 mammalian samples. For each mammalian DNA sample, PCR products were analyzed by gel electrophoresis with modified universal primers. Direct sequencing was performed using a BigDye Terminator v1.1 Cycle Sequencing kit and an ABI 3130xl Genetic Analyzer. Each sequence was evaluated by a nucleotide BLAST homology search. The top hits for sequence homology for each sample matched the actual species, or closely-related species. In conclusion, this effective method may be used in routine forensic practices to identify the species of unknown mammalian biological samples, such as from blood, body fluid, tissue, hair, and bone.

　In forensic anthropology, the histological structure of compact bone is useful for distinguishing human from non-human bone and for age estimation. A saw mark on the bone surface is also analyzed to estimate the implement that cut the bone. However, extensive time and technical proficiency are required to prepare a specimen for obtaining a clear image of the compact bone structure in optical microscopy. Moreover, clear detection of a saw mark is inhibited by the limited focal depth of optical microscopy and by the color tone of bones. The purpose of this study is to evaluate imaging mode of scanning electron microscope (SEM) and preparation of bone specimen to readily obtain a clear image of the compact bone structure and saw mark in a shorter time. In this paper, a transverse section of a long bone was polished to a mirror finish, completed within a few minutes by a simple method, to observe the compact bone structure. In consequence, Haversian canal, bone lacuna, and lamellar structure in the compact bone were clearly observed with compositional (COMPO) image in the backscattered electron mode. Meanwhile, the saw mark was also clearly recognized as a convexo-concave on the transverse section of the long bone with topographic (TOPO) image in the backscattered electron mode. Thus, SEM is useful to observe the compact bone structure and saw mark simply, rapidly, and clearly for practical use in forensic anthropology.

　In the Japanese population, D19S433 silent allele is rarely detected in cases of testing with commercial STR kits. The silent allele causes inconsistency of STR typing results between kits and false negative parentage despite the true biological parentage. The cause of this problematical mismatch is reported that the mutation is a base change (G>A) 32 nucleotides downstream from the 3′ end of the AAGG repeats (G32A), so reverse primer in STR kits fail to anneal to the binding site, consequently no STR peak or extremely low peak is detected. In this study, volunteers originated from 4 silent-allelic pedigrees are examined whether the silent allele was judged by AmpFlSTR Identifiler Plus PCR amplification kit, PowerPlex Fusion system, and GlobalFiler PCR amplification kit, furthermore they carry G32A mutation or not by direct sequencing, SNaPshot genotyping, and TaqMan genotyping. In conclusion, it has been identified that all silent-allelic peaks are caused by G32A mutation and followed by Mendelian genetics. Actually, some factors influence the formation of silent allele, such as primer binding fidelity, improvement of other PCR reagents, and PCR cycle conditions. When the suspected silent-allelic peak appears, additional tests with multiple STR kits which containing alternative primer will be recommended.

　In previous studies, the analysis of solid blue automotive paints using scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX) was reported. The X-ray intensity ratios of ClK_α/TiK_α and CuK_α/TiK_α in solid blue model paints have liner relations with the weight ratio of 8 kinds of phthalocyanine blue pigments to titanium white pigment and these ratios are useful to discriminate solid blue automotive paints.

　In this study, green model paints that were manufactured by using 2 kinds of phthalocyanine green pigments and titanium white pigment were supplied from a paint manufacture and were analyzed by SEM/EDX.

　Cl, Cu and Br were originated from chlorinated and brominated copper phthalocyanine. Ti was originated from titanium dioxide. And it was indicated that these X-ray intensity ratios of ClK_α/TiK_α, CuK_α/TiK_α and BrK_α/TiK_α in the model paints have liner relations with the weight ratio of green pigment to white pigment. Furthermore, the X-ray intensity ratio of ClK_α/CuK_α and BrK_α/CuK_α in model paints showed chlorinated and brominated copper phtalocyanine.

　The cultivar cannabis (Cannabis sativa L.) ‘Tochigi-shiro’ has been developed by the Tochigi Prefectural Institute of Public Health and Environmental Science and Tochigi Prefectural Agricultural Experiment Station. It is considered nontoxic and a fiber-type cannabis because of its low concentration of the hallucinogen Δ⁹-tetrahydrocannabinol (THC). Recently, concentrated forms of cannabis, such as butane hash oil (BHO), have spread globally, and seizures of BHO have increased in Japan. We expect that the use of BHO prepared from Tochigi-shiro may be detrimental to health. However, the concentrations of cannabinoids in Tochigi-shiro have not previously been reported. In this study, the concentrations of THC, cannabidiol (CBD), cannabinol, and tetrahydrocannabivarin in Tochigi-shiro cultivated in Tochigi Prefecture were measured. Further, BHO was produced from the leaves of Tochigi-shiro using commercially available extraction devices to determine the extraction efficiency of THC and CBD. THC was detected in Tochigi-shiro, and concentrations of each cannabinoid differed between plants grown at three sites in Tochigi Prefecture. However, the concentration ratio of CBD to THC was almost the same in plants from all three sites. In BHO, the concentrations of THC and CBD were 6.59% w/w and 35.0% w/w, respectively. This indicates that the concentrations of THC and CBD were approximately 55- and 35-fold greater, respectively, in BHO than in the leaves of plants before butane gas extraction. We confirmed that the concentration of THC in plants was low, whereas the concentration in BHO was high. In the BHO manufactured from Tochigi-shiro, the CBD concentration was five times higher than that of THC. Moreover, CBD can antagonize the psychotomimetic symptoms caused by THC. Therefore, even if BHO produced from this plant was used, the effect of THC would hardly be obtained. Currently, interest in cannabis is increasing worldwide. The traditional industry producing cannabis as a source of fiber may be affected by the theft of Tochigi-shiro. The results of the present study are relevant to prefectural and city governments and cultivators, and suggest the need for additional protection of cultivated fields against theft.

　This study is aimed to establish whether the skin preparation using ethanol (EA)-containing skin antiseptics causes EA contamination through blood collection. Venous blood was collected from 40 healthy volunteers according to the national guidelines for blood sampling, with four sequential procedures as follows: 1) collecting immediately (within 5 s) after cleaning the skin with each packaging type of EA-containing pad, 2) collecting 1 minute after cleaning the skin with each packaging type of EA-containing pad, 3) collecting immediately (within 5 s) after cleaning the skin with a traditional cleaning method (with a thoroughly EA-impregnated pad, and 4) collecting 1 minute after cleaning the skin with a traditional cleaning method. Each sequential procedure was performed with and without the EA-containing pad used for skin cleaning pressed against the puncture site on their right and left arms at the time the needle was withdrawn, respectively. The collected specimens were subjected to determination of EA by using head space gas chromatography-mass spectrometry.

　In every 80 blood specimen obtained from 40 participants, EA was undetectable (<0.001 mg/mL). This study demonstrates that disinfection using ethanol-containing skin antiseptics is unlikely to cause ethanol contamination through blood collection regardless of skin preparation technique according to the guidelines for blood sampling.

 DNA obtained from hard tissues, such as bones and teeth, is used to identify highly decomposed or skeletonized corpses. Effective DNA extraction is critical; the quantity and quality of DNA and the levels of co-extracted PCR inhibitors greatly influence subsequent steps. We evaluated three methods used to extract DNA from bones and teeth: use of the QIAamp DNA Mini Kit (Qiagen), the standard phenol/chloroform-based method, and the PrepFiler Express BTA Forensic DNA Extraction Kit (Thermo Fisher Scientific). We modified the protocols of the two kits. We assessed DNA quantity and quality. The QIAamp DNA Mini Kit yielded more DNA and more informative STR profiles than did the other methods; that kit is optimal.