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The identification of accelerant about gasoline and other ignited liquids in arson has always been a difficult problem in the field of physical evidence identification. How to avoid “false positive” and “false negative” results is a key issue. To study the interference of diene rubber on gasoline identification from two aspects of “false positives” and “false negatives”, and to explore its degree when gasoline was mixed with diene rubber in different proportions, the combustion residues obtained from cis-polybutadiene rubber, isobutylene isoprene rubber and styrene butadiene rubber after loading different amounts of gasoline were compared using gas chromatography-mass spectrometry (GC-MS). The results showed that alkanes, alkenes/cycloalkanes, aromatic-alkylbenzenes, homologs of indenes and indanes, alkylnaphthalenes and polycyclic aromatic hydrocarbons were detected in the combustion residues of the three kinds of diene rubber samples before and after gasoline loading, which was consistent with gasoline in terms of the characteristic components categories and had strong interference with gasoline identification. After loading 0.05 mL and 0.1 mL gasoline respectively into 5 g rubber sample, there was no significant changes in the characteristic components of cycloalkanes/alkenes, alkylnaphthalenes, and polycyclic aromatic hydrocarbons in the rubber combustion residues. The number and relative peak area ratio of characteristic peaks corresponding to aromatic-alkylbenzenes, homologs of indenes and indanes changed to different degrees, while the changes of alkylbenzenes were more representative. Loading gasoline or not had little effect on the ratio of the characteristic peaks of C2 benzene components in the combustion residues of cis-polybutadiene rubber. The ratio among three characteristic peaks of C2 benzene components in the combustion residues of isobutylene isoprene rubber and styrene butadiene rubber samples changed significantly when the gasoline loading amount reached 0.1 mL. This study can provide important references for the gasoline identification when there is a presence of diene rubber matrix in practical work.

Objective: To explore the single nucleotide polymorphism(SNP) of mitochondrial DNA (mtDNA) D-LOOP region in peripheral blood lymphocytes of immuno-related pancytopenia (IRP) patients and its correlation with immune parameters., Methods: The D-LOOP region in mitochondrial DNA of lymphocytes in peripheral blood mononuclear cells from 43 patients with untreated IRP was detected by polymerase chain reaction(PCR). The PCR products were sequenced by the pros and cons direct sequencing methods. The sequencing results were compared with the revised Cambridge reference sequence (rCRS) and the Polymorphic Sites of Human Mitochondrial Genome Database., Results: Among total of 110 variant positions of D-LOOP region in 43 patients, 62 was SNP sites and 48 was mutation sites, of which 14 were the new mutation sites not yet registered in the database, 516 base variations were observed at 110 positions, the most common variations were base substitutions, among them T/C and A/G was 184/410 and 113/410 respectively. In the 110 variant positions, the high frequency variation sites were 73 and 263 for 43/43,311 for 32/43,310 and 16 224 for 27/43,16 519 for 25/43, 489 and 16 362 for 24/43. By the analysis of mitochondrial DNA D-LOOP polymorphism and related clinical immunology indicators of the patient's lymphocytes, it was found that D-loop in adult patients (age≥ 18 years old) significantly correlated with CD15 IgM, GLYCoA + Cells IgM, CD34 + CellsIgG, CD34 + Cells IgM correlation., Conclusion: The high frequency of polymorphism exists in mitochondrial DNA D-loop region of lymphocytes in IRPA patients, and was significantly correlates with the autoantibodies in bone marrow mononuclear cells in adult patients, which may be associated with the IRP occurrence.