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Mitochondrial DNA (mtDNA) is an important genetic marker for degraded biological sample identification, maternal pedigree tracing, and population genetic structure study owing to its characteristics of high copy number, anti-degradable ring structure, and maternal inheritance. Whole mtDNA genome sequencing is an optimal method for the analysis of mtDNA polymorphism and heterogeneity because it allows for the comprehensive use of maternal genetic information. However, because of lacking quantitative evaluations for sequencing data, the scientific interpretation standards for mtDNA sequencing results of the previously used sequencing systems are often different, and false positive or false negative results are prone to occur when faced with the interference of nuclear genomic DNA, or the heterogeneities of mtDNA sequence and structure. In this study, we evaluated a novel mtDNA whole genome sequencing system using long fragment amplification strategy on the DNA nanoball (DNB) sequencing platform. This system demonstrated high sequencing quality and specific mtDNA sequencing efficiencies on positive control DNA and FTA bloodstain samples, as the average Q20 and Q30 values of the corresponding samples were 97.17 % and 91.93 %; 97.37 % and 92.48 %, respectively. The mean mapping percentages for the reference sequences of whole genome DNA (wgDNA), mtDNA, and nuclear genomic DNA (ngDNA) in the corresponding samples were 99.98 %, 99.97 %, 0.03 %, and 99.91 %, 99.40 %, 0.60 %; respectively. The average error calling rates for the bases A, C, G, and T of the whole mtDNA genome were 0.2519 %, 0.2550 %, 0.2906 %; and 0.2392 %, respectively. The efficacy of heteroplasmy identification was assessed using a set of theoretical sites with predetermined rates. These sites were created by combining the samples with known mtDNA haplotypes in certain proportions. The absolute errors between observed and theoretical heteroplasmy values were 89.59 %, 74.68 %, 50.20 %, 12.65 %, 8.31 %, and 4.85 %, while the theoretical heteroplasmy values were 5 %, 10 %, 20 %, 80 %, 90 %, and 95 %, respectively. The absolute error exhibited relative stability when the mtDNA sequencing depth exceeded 500×. Furthermore, the system sequencing efficiency was also confirmed among different kinds of samples, and these samples included natural samples (e.g., peripheral blood samples preserved on FTA cards for 2 and 11 years, and on filter paper for 6 and 9 years), degraded samples, sensitivity samples, samples derived from various bodily fluids, and maternal pedigree samples. In summary, the whole mtDNA genome sequencing system used for forensic identification demonstrated high performance in analyzing mtDNA sequence information, and showed significant prospects for forensic application and maternal genetic research.

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There are many reports on g-C3N4 nanosheet and BiOCl nanosheet, but few studies on other morphologies of g-C3N4 and BiOCl. Herein, a g-C3N4 nanoball/BiOCl nanotube heterojunction prepared by a simple one-step acetonitrile solvothermal method is reported. The XRD results prove that the g-C3N4/BiOCl composites can be prepared in one step. SEM results revealed that the g-C3N4 was spherical and the BiOCl was tubular. The HRTEM results indicate that g-C3N4 has an amorphous structure and that the (100) crystal plane of BiOCl borders the g-C3N4. Spherical g-C3N4 has a narrow band gap (approximately 1.94 eV), and the band gap of g-C3N4/BiOCl after modification was also narrow. When the BiOCl accounted for 30% of the g-C3N4/BiOCl by mass, the quasi-primary reaction rate constant of RhB degradation was 45 times that of g-C3N4. This successful preparation method for optimizing g-C3N4 involving simple one-step template-free synthesis may be adopted for the preparation of diverse-shapes and high-performance nanomaterials in the future.

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Illumina is the leading sequencing platform in the next-generation sequencing (NGS) market globally. In recent years, MGI Tech has presented a series of new sequencers, including DNBSEQ-T7, MGISEQ-2000 and MGISEQ-200. As a complex application of NGS, cancer-detecting panels pose increasing demands for the high accuracy and sensitivity of sequencing and data analysis. In this study, we used the same capture DNA libraries constructed based on the Illumina protocol to evaluate the performance of the Illumina Nextseq500 and MGISEQ-2000 sequencing platforms. We found that the two platforms had high consistency in the results of hotspot mutation analysis; more importantly, we found that there was a significant loss of fragments in the 101-133 bp size range on the MGISEQ-2000 sequencing platform for Illumina libraries, but not for the capture DNA libraries prepared based on the MGISEQ protocol. This phenomenon may indicate fragment selection or low fragment ligation efficiency during the DNA circularization step, which is a unique step of the MGISEQ-2000 sequence platform. In conclusion, these different sequencing libraries and corresponding sequencing platforms are compatible with each other, but protocol and platform selection need to be carefully evaluated in combination with research purpose.

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Herein we reported the effect of doping and addition of surfactant on SnO2 nanostructures for enhanced photocatalytic activity. Pristine SnO2, Zn-SnO2 and SDS-(Zn-SnO2) was prepared via simple co-precipitation method and the product was annealed at 600 °C to obtain a clear phase. The structural, optical, vibrational, morphological characteristics of the synthesized SnO2, Zn-SnO2 and SDS-(Zn-SnO2) product were investigated. SnO2, Zn-SnO2 and SDS-(Zn-SnO2) possess crystallite size of 20 nm, 19 nm and 18 nm correspondingly with tetragonal structure and high purity. The metal oxygen vibrations were present in FT-IR spectra. The obtained bandgap energies of SnO2, Zn-SnO2 and SDS-(Zn-SnO2) were 3.58 eV, 3.51 eV and 2.81 eV due to the effect of dopant and surfactant. This narrowing of bandgap helped in the photocatalytic activity. The morphology of the pristine sample showed poor growth of nanostructures with high level of agglomeration which was effectively reduced for other two samples. Product photocatalytic action was tested beneath visible light of 300 W. SDS-(Zn-SnO2) nanostructure efficiency showed 90% degradation of RhB dye which is 2.5 times higher than pristine sample. Narrow bandgap, crystallite size, better growth of nanostructures paved the way for SDS-(Zn-SnO2) to degrade the toxic pollutant. The superior performance and individuality of SDS-(Zn-SnO2) will makes it a potential competitor on reducing toxic pollutants from wastewater in future research.

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【Objective】 To investigate the changes of platelet microRNA (miRNA) expression profiles on d1 and d5 during storage with riboflavin and ultraviolet-B (UVB) light (VB2-PRT) treatment, and to explore the molecular mechanism of miRNAs involved in the regulation of platelet storage lesion (PSL) under VB2-PRT treatment. 【Methods】 20 apheresis platelet concentrates (5mL / sample) were collected from voluntary blood donors. After mixing and shaking, the samples was treated with riboflavin (final concentration 50 μmol/L) and 6.24J/mL UVB light for 8min, then split into two aliquots and agitated stored at (22±2) ℃. The concentrates were sampled (5mL) on d1 and d5, respectively, and sequenced by DNA nanoball (DNB) sequencing technology. The differentially expressed miRNAs between the two groups (at different storage periods) were screened by DEGseq and MA-plot analysis software. The miRNAs, reached more than 2 times different expression between groups, were considered significant different(P<0.01). The miRanda and TargetScan softwares were used to predict the target genes. Gene Ontology (GO) function enrichment analysis and Kyoto Encyclopedia of genes and genomes (KEGG) pathway enrichment analysis were performed on the target genes of significant differentially expressed miRNAs. The expression of miRNAs was verified by real-time fluorescence quantitative PCR (qRT-PCR). 【Results】 miRNA expression profile: compared with d1 platelets, there were 590 miRNAs with significantly different expression (P< 0.01) in d5 group, including 255 up-regulated miRNAs (such as miR-99b, miR-7) and 335 down regulated miRNAs (such as miR-451a, miR-19b). Among the 272 known miRNAs, 112 were up-regulated and 160 were down regulated. There were 318 new miRNAs sequences. The enriched GO terms of target genes of differentially expressed miRNAs in d5 and d1 groups included cell components, organelles, cell membranes and other cellular structures, molecular functions such as adhesion, catalysis, molecular conversion, transportation, transcription factor and receptor activity, and biological processes such as cell processing, metabolism, biological regulation and stress. The corresponding pathways in the top 10 of KEGG enrichment were mainly secretion, glucose metabolism, signal transduction, membrane transport, translation, environmental adaptation and other signal pathways. The six randomly selected differentially expressed miRNAs verified by qRT-PCR was consistent with those of DNB sequencing. 【Conclusion】 The expression profiles of platelets miRNAs has changed significantly between d1- and d5-storage under VB2-PRT treatment. Functional prediction suggests that these miRNAs might be involved in the regulation of platelet PSL underVB2-PRT treatment.

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BACKGROUND: Massively-parallel-sequencing, coupled with sample multiplexing, has made genetic tests broadly affordable. However, intractable index mis-assignments (commonly exceeds 1%) were repeatedly reported on some widely used sequencing platforms. RESULTS: Here, we investigated this quality issue on BGI sequencers using three library preparation methods: whole genome sequencing (WGS) with PCR, PCR-free WGS, and two-step targeted PCR. BGI's sequencers utilize a unique DNA nanoball (DNB) technology which uses rolling circle replication for DNA-nanoball preparation; this linear amplification is PCR free and can avoid error accumulation. We demonstrated that single index mis-assignment from free indexed oligos occurs at a rate of one in 36 million reads, suggesting virtually no index hopping during DNB creation and arraying. Furthermore, the DNB-based NGS libraries have achieved an unprecedentedly low sample-to-sample mis-assignment rate of 0.0001 to 0.0004% under recommended procedures. CONCLUSIONS: Single indexing with DNB technology provides a simple but effective method for sensitive genetic assays with large sample numbers.

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The design and construction of metal-organic polyhedra has received much attention by chemists due to the intriguing diversity of architectures and topologies that can be achieved. There are several crucial factors which should be considered for the construction of metal-organic polyhedra, such as the starting materials, reaction time and temperature, solvent and suitable organic ligands. Recently, polyoxometalates (POMs), serving as secondary building units to construct POM-based metal-organic polyhedra, have been the subject of much interest. The title compound, dodecakis(dimethylammonium) octakis(µ-benzene-1,3,5-tricarboxylato)hexa-µ-chlorido-tetracosa-µ-oxido-triacontaoxidotriacontavanadium, (NH2Me2)12[(V5O9Cl)6(C9H3O6)8], was synthesized successfully by self-assembly of VOCl3 and benzene-1,3,5-tricarboxylic acid under solvothermal conditions. The title polyhedron has an rdo topology when the {V5O9Cl} building unit and the benzene-1,3,5-tricarboxylate (BTC3-) ligand were simplified into 4-connected and 3-connected vertices. Interestingly, when the {V5O9Cl} building unit and the BTC3- ligand are considered as quadrangular and triangular faces, the structure displays rhombicuboctahedral geometry with an outer diameter of 21.88 Å. The packing of the polyhedra produces a circular channel with a diameter of 8.2 Å. The title compound was characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetric analysis and powder X-ray diffraction.