[Correlation between bioelectrical impedance and nutritional status in neurocritical care patients]

Objective: To explore the correlation between electrical impedance indicators and commonly used nutritional indicators in neurocritical care patients. Methods: A cross-sectional study was conducted to collect 58 neurocritical care patients in neurosurgery Department of Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from June to September 2022. Bioelectrical impedance tests were performed after surgery or one week after injury, and nutrition-related biochemical indicators of the patients were collected on the same day, including nutritional status related indicators, inflammation related indicators, anemia related indicators and blood lipid related indicators. The patients were assessed with acute physiology and chronic health evaluation (APACHE) Ⅱ score and sequential organ failure assessment (SOFA) score. Based on the results obtained, the patients were assessed with nutritional score and spearman correlation analysis. The correlations of electrical impedance with nutrition related indicators and nutrition risk related indicators were analyzed. The prediction model of nutritional status was constructed by multi-factor binary logistic regression. Stepwise regression was used to screen electrical impedance indicators related to nutritional status. The receiver operating characteristic (ROC) curve was plotted and the area under the curve (AUC) was calculated to evaluate the predictive ability of the nutritional status prediction model. Results: A total of 58 patients were collected, including 33 males and 25 females, and aged 72.0 (59.0, 81.8) years. Extracellular water (ECW) was positively correlated with interleukin 6 (r=0.529, P<0.001). The edema index [ECW/total body water (TBW)] was negatively correlated with albumin (r=-0.700, P<0.001), hematocrit (r=-0.641, P<0.001) and hemoglobin (r=-0.667, P<0.001). The phase angle was positively correlated with albumin (r_RA=0.667, r_LA=0.649, r_RL=0.669, r_LL=0.685, all P<0.001), hematocrit (r_RA=0.600, r_LA=0.604, r_TR=0.565, r_RL=0.529, r_LL=0.602, all P<0.001) and hemoglobin (r_RA=0.626, r_LA=0.635, r_TR=0.594, r_RL=0.624, r_LL=0.631, all P<0.001). By stepwise regression screening of predictive factors for nutritional status and incorporating age, gender and white blood cells as confounding factors into the model, the final model was obtained as follows: nutritional status=-0.01×age+1.22×gender-0.12×white blood cells+202.20×ECW/TBW+0.5 torso phase angle -82.16 [The OR value of ECW/TBW: 20.8 (95%CI: 3.7-117.1), P<0.001], with the AUC of 0.921. Conclusion: Bioelectrical impedance indicators have good correlations with commonly used clinical nutritional indicators, and can provide a new method for nutritional evaluation of neurocritical care patients.

Geolocation Inference of Forensic Individual Origin by Soil Metagenomic Analysis

Abstract

Objective To preliminarily discuss the feasibility of geolocation inference of forensic individual origin by soil metagenomic analysis. Methods The 33 soil samples from Heilongjiang, Qinghai and Tibet were collected, total bacterial DNA in the samples were extracted, and universal primers were used to amplify the V3 and V4 hypervariable region of bacterial 16S rDNA. The region was sequenced by high-throughput sequencing （HTS） with the MiSeq sequencer. Bioinformatics analysis such as species composition and sample comparison was performed on sequencing data. The richness index and diversity index were calculated based on operational taxonomic unit （OTU） results. Results A total of 2 720 149 sequences were generated by sequencing. Those sequences were clustered into 114 848 OTUs. The Chao1 indexes of soil microorganisms in Heilongjiang, Qinghai, and Tibet were 797.45, 745.11 and 535.98, respectively, and Shannon indexes were 6.46, 6.36 and 6.25, respectively. The number of bacterial species and the community diversity in the soil from high to low were Heilongjiang > Qinghai > Tibet. The composition of soil bacteria in three provinces at various classification levels were obtained, the dominant genuses in Heilongjiang were Chthoniobacteraceae DA101 and an unannotated genus of Thermogemmatisporaceae; the dominant genuses in Qinghai were an unannotated genus of Cytophagaceae and an unannotated genus of Nocardioidaceae; the dominant genuses in Tibet were an unannotated genus of Comamonadaceae and Verrucomicrobiaceae Luteolibacter. The results of principal co-ordinates analysis demonstrated that, according to the weighted UniFrac analysis, the three principle components represented 56.36% of the total variable, and according to the unweighted UniFrac analysis, the three principle components represented 34.81% of the total variable. The samples from the same province could be clustered together, and the species and content of soil microorganisms from different provinces were significantly different. Conclusion Based on the metagenomic analysis method, soil samples from different regions can be effectively distinguished, which has potential application value in geolocation inference of forensic individual origin in the future.

Mitochondrial DNA Heteroplasmy of Hair Shaft Using HID Ion GeneStudioTM S5 Sequencing System

Objective To study the heteroplasmy of the whole mitochondrial genome genotyping result of hair shaft samples using HID Ion GeneStudio^TM S5 Sequencing System. Methods The buccal swabs and blood of 8 unrelated individuals, and hair shaft samples from different parts of the same individual were collected. Amplification of whole mitochondrial genome was performed using Precision ID mtDNA Whole Genome Panel. Analysis and detection of whole mitochondrial genome were carried out using the HID Ion GeneStudio^TM S5 Sequencing System. Results The mitochondrial DNA sequences in temporal hair shaft samples from 2 individuals showed heteroplasmy, while whole mitochondrial genome genotyping results of buccal swabs, blood, and hair samples from the other 6 unrelated individuals were consistent. A total of 119 base variations were observed from the 8 unrelated individuals. The numbers of variable sites of the individuals were 29, 40, 38, 35, 13, 36, 40 and 35, respectively. Conclusion Sequence polymorphism can be fully understood using HID Ion GeneStudio^TM S5 Sequencing system.

Advancements in Single-cell Sequencing and the Prospect of Its Forensic Application

Abstract

Single-cell sequencing is a technique that analyzes DNA and RNA sequences on the cellular level with next generation sequencing. The ultra high resolution of single-cell sequencing provides new perspectives and opens new frontiers for our understanding of many areas of life sciences, including forensic genome. This paper summarizes the recent advancements in single-cell sequencing and the prospect of its forensic application.

[Application of Metagenomics in Forensic Identification]

With the development of molecular biology and genomics, metagenomics is playing a more important role in forensic science and forensic identification. In recent years, as a branch discipline studying the composition profile and diversity of microbe flora as well as studying the interaction within microbe and with environment, the application of metagenomics has gradually risen and brought new opportunities for forensic identification-related area. In this review, strategy of metagenomics and its application in forensic identification including individual identification, origin determination of biological stain in crime scene and drug abuse detection are summarized. This article aims to elucidate the role and application value of metagenomics in forensic science.

Shear stress-driven refreshing capability of plastic deformation in nanolayered metals

Severely localized deformation within shear bands can occur much more easily in a metal with nanoscale microstructures, such as nanograined and nanolayered materials. Based on atomic-scale observations, here we show that such locally large deformation (the continuous thinning of the layers) within the indentation-induced shear bands of the Cu/Au nanolayers is essentially attributed to the large shear stress component along the interface, which can refresh the capability of the interface to absorb incoming dislocations through unlocking the product of the dislocation-interface reaction. The results have implications for understanding the interface-mediated mechanisms of plastic deformation and for the engineering application of severe plastic deformation processing of metals at nanoscales.

Ultra-sensitive analysis of a cantilevered single-walled carbon nanocone-based mass detector

The ultra-sensitivity of mass detectors using individual cantilevered single-walled carbon nanocone (SWCNC) resonators is first investigated. A higher-order gradient theory, derived at the atomic level, is applied for modeling SWCNC resonators. Numerical simulations using a mesh-free computational framework based on moving Kriging interpolation are conducted to investigate the mass sensitivity of cantilevered SWCNC resonators with extra mass loading as well as with equivalent single-walled carbon nanotube (SWCNT) resonators. Comparison of the magnitude of resonant frequency shifts, the key criterion for mass sensitivity, of these two kinds of resonators demonstrates a far higher mass sensitivity for SWCNC resonators than for SWCNT resonators, thus suggesting a new method for ultra-sensitive mass detection via SWCNC resonators. The dependence of the mass sensitivity of SWCNC resonators on height and top radii has been examined. A reduction in the height of SWCNC resonators gives rise to a considerable increase in mass sensitivity. The mass sensitivity of a 6 nm high SWCNC resonator can even reach a level of 10(-22) g. It is noteworthy that the top radii of SWCNC resonators have a slight effect on frequency shifts. Another interesting observed phenomenon is that a deviation in the height of 19.2° SWCNC resonators leads to little loss in precision of mass detection when the attached mass is smaller than 10(-20) g. This superior characteristic indicates that SWCNC-based mass detectors have great potential in practical applications.

[Genetic polymorphisms of 9 STR loci in Achang ethnic group in Yunnan Province]

Blood samples were collected from the unreleatled individuals in the Achang ethnic group in Yunnan Province. Genetic distribution for nine STR loci and amelogenin locus were determined in Achang ethnic group based on GeneScan. 96 samples were denatured of gel electrophoresis. The databanks in Achang ethnic group were generated by using GeneScan, genotyper, and genetic distribution analysis. 69 alleses and 166 genotypers were observed, with the corresponding frequency being 0.0050-0.6100 and 0.0100-0.3900. The average H is 0.7381. The comulated DP is 0.9999999. The comulated EPP is 0.9999989. The allele distribution of the loci was in good agreement with the Handy-Weibeng equilibrium. It is useful to establishing DNA databanks for studying gene natural resources, very valuable in the study of forensic science, anthropology and ethnic.