Groundwater chemical characteristic analysis and water source identification model study in Gubei coal mine, Northern Anhui Province, China.

This study aims to accurately identify mine water sources and reduce the hazards caused by water inrush accidents in coal mines. Taking the Gubei coal mine as an example, the water quality results of the water samples from the Cenozoic unconsolidated aquifer, Permian sandstone fracture aquifer, and Carboniferous Taiyuan Formation limestone karst fracture aquifer in the mine area were tested, and K++Na+, Ca2+, Mg2+, Cl-, SO42-, HCO3-, TDS (Total Dissolved Solids), and pH were selected as the main indicators to study the water chemistry characteristics of the aquifer through water chemistry component analysis, major ion content analysis, Piper trilinear analysis, and correlation analysis. Thirty-five groups of water samples were randomly selected and imported into SPSS software for factor analysis (FA) and downsized to three main factors as the input variables of the artificial neural network model. The particle swarm optimization (PSO) code was written based on the MATLAB platform to improve the self-adjustment weights and acceleration factors for optimizing the initial weights and thresholds of the Back-Propagation (BP) neural network. The training and prediction samples were learned in the ratio of 8:2, and the recognition results were compared with the traditional BP neural network model. Results showed that the groundwater of the Gubei coal mine demonstrated a water quality vertical zoning pattern, and the chemical composition was dominated by cation K++Na+ and anion Cl-. The FA-PSO-BP neural network model has a higher accuracy of water source discrimination compared with the cluster analysis and the FA-BP neural network model. The FA-PSO-BP neural network model is worthy of further application in the problem of water source identification in mine water inrush.

Association between triglyceride glucose index and severity of diabetic foot ulcers in type 2 diabetes mellitus.

BACKGROUND: Triglyceride glucose (TyG) index is a good surrogate biomarker to evaluate insulin resistance (IR). The study aimed to investigate whether the TyG index is related to the severity of diabetic foot ulcers (DFUs) in patients with type 2 diabetes mellitus (T2DM). METHODS: A total of 1059 T2DM patients were enrolled in this observational, retrospective, single-center study. TyG index was calculated as ln[fasting triglycerides (mg/dl) × fasting glucose (mg/ dl)/2]. The severity of DFUs was classified into mild-to-moderate DFUs (Wagner grade score < 3) and severe DFUs (Wagner grade score ≥ 3) based on Wagner classification. Patients were stratified according to the tertiles of TyG index. Logistic regression models were implemented to explore the association between TyG index and the severity of DFUs. Subgroup analyses were used to verify the reliability of results. RESULTS: Compared with the reference lowest TyG tertile (T1), the highest tertile (T3) was associated with 0.377-fold increased risk of prevalence of severe DFUs (odds ratio [OR] 1.377, 95% confidence interval [CI] 1.017-1.865) (P = 0.039). After adjusting for potential confounders, the multivariable-adjusted OR and 95% CI were 1.506 (1.079-2.103) (P = 0.016) in patients with highest tertile. Moreover, subgroup analyses indicated that the association was stronger among men, patients with age ≥ 65 years, duration of diabetes more than 10 years, or without PAD. CONCLUSIONS: Elevated TyG index is independently associated with severity of DFUs even after adjusting conventional confounders.

Pre- and post-pollination barriers between two exotic and five native Sagittaria species: Implications for species conservation.

Anthropogenic introduction of species has resulted in a breakdown of geographical barriers and hybridization in previously allopatric species. Thus, examining hybridization proneness of exotic species contributes to revealing its potential threat. Moreover, reproductive barriers may be strengthened or weakened due to long-term geographical isolation for these newly sympatric species. However, few studies have evaluated multiple barriers between alien and native species. In this study, we quantified the importance of four pre-pollination barriers (phenological, floral traits, pollen production, and floral constancy) and four post-pollination barriers (pollen-pistil incompatibility, seed set, seed viability, and seedling survival) between two introduced and five native Sagittaria species. Results showed that introduced S. platyphylla was cross-compatible with two native species, whereas introduced S. montevidensis was incapable of hybridizing with any native species. Different barriers were asymmetric within species pairs and multiple barriers acted in concert to maintain species boundaries. Post-pollination barriers contributed more to total reproductive isolation in native species, whereas pre-pollination barriers played a stronger role in total reproductive isolation for two introduced species. Seed set was the only barrier that was positively correlated with genetic distance. Our results provide a perspective to better understand reproductive barriers for secondary contact species. We highlight the importance of monitoring hybridization events before human introduction and the possible conservation strategies to remove invasive species with hybridization proneness.

Extremely High-Quality Periodic Structures on ITO Film Efficiently Fabricated by Femtosecond Pulse Train Output from a Frequency-Doubled Fabry-Perot Cavity.

This study developed a novel frequency-doubled Fabry-Perot cavity method based on a femtosecond laser of 1030 nm, 190 fs, 1 mJ, and 1 kHz. The time interval (60-1000 ps) and attenuation ratio (0.5-0.9) between adjacent sub-pulses of the 515 nm pulse train were able to be easily adjusted, while the efficiency was up to 50% and remained unchanged. Extremely high-quality low-spatial-frequency LIPSS (LSFL) was efficiently fabricated on an indium tin oxide (ITO) film using a pulse train with a time interval of 150 ps and attenuation ratio of 0.9 focused with a cylindrical lens. Compared with the LSFL induced by the primary Gaussian pulse, the uniformity of the LSFL period was enhanced from 481 ± 41 nm to 435 ± 8 nm, the divergence of structural orientation angle was reduced from 15.6° to 3.7°, and the depth was enhanced from 74.21 ± 14.35 nm to 150.6 ± 8.63 nm. The average line edge roughness and line height roughness were only 7.34 nm and 2.06 nm, respectively. The depths and roughness values were close to or exceeded those of resist lines made by the interference lithography. Compared with the common Fabry-Perot cavity, the laser energy efficiency of the pulse trains and manufacturing efficiency were enhanced by factors of 19 and 25. A very colorful "lotus" pattern with a size of 30×28 mm2 was demonstrated, which was covered with high-quality LSFLs fabricated by a pulse train with optimized laser parameters. Pulse trains can efficiently enhance and prolong the excitation of surface plasmon polaritons, inhibit deposition particles, depress ablation residual heat and thermal shock waves, and eliminate high-spatial-frequency LIPSS formed on LSFL, therefore, producing extremely high-quality LSFL on ITO films.

Regular Periodic Surface Structures on Indium Tin Oxide Film Efficiently Fabricated by Femtosecond Laser Direct Writing with a Cylindrical Lens.

Regular laser-induced periodic surface structures (LIPSS) were efficiently fabricated on indium tin oxide (ITO) films by femtosecond laser direct writing with a cylindrical lens. It was found that randomly distributed nanoparticles and high spatial frequency LIPSSs (HSFL) formed on the surface after a small number of cumulative incident laser pulses per spot, and regular low spatial frequency LIPSSs (LSFL) appeared when more laser pulses accumulated. The mechanism of the transition was studied by real-time absorptance measurement and theoretical simulation. Results show that the interference between incident laser and surface plasmon polaritons (SPPs) excited by random surface scatterers facilitates the formation of prototype LSFLs, which in turn enhances light absorption and SPP excitation following laser pulses. The effects of scanning velocity and laser fluence on LSFL quality were discussed in detail. Moreover, large-area extremely regular LSFL with a diameter of 30 mm were efficiently fabricated on an ITO film by femtosecond laser direct writing with the cylindrical lens. The fabricated LSFLs on the ITO film demonstrate vivid structural color. During LSFL processing, the decrease of ITO film thickness leads to the increase of near-infrared optical transmittance.

Preclinical efficacy of stem cell therapy for skin flap: a systematic review and meta-analysis.

BACKGROUND: A skin flap is one of the most critical surgical techniques for the restoration of cutaneous defects. However, the distal necrosis of the skin flap severely restricts the clinical application of flap surgery. As there is no consensus on the treatment methods to prevent distal necrosis of skin flaps, more effective and feasible interventions to prevent skin flaps from necrosis are urgently needed. Stem therapy as a potential method to improve the survival rate of skin flaps is receiving increasing attention. METHODS: This review followed the recommendations from the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statements. Twenty studies with 500 animals were included by searching Web of Science, EMBASE, PubMed, and Cochrane Library databases, up until October 8, 2020. Moreover, the references of the included articles were searched manually to obtain other studies. All analyses were conducted using Review Manager V.5.3 software. RESULTS: Meta-analysis of all 20 studies demonstrated stem cell treatment has significant effects on reducing necrosis of skin flap compared with the control group (SMD: 3.20, 95% CI 2.47 to 3.93). Besides, subgroup analysis showed differences in the efficacy of stem cells in improving the survival rate of skin flaps in areas of skin flap, cell type, transplant types, and method of administration of stem cells. The meta-analysis also showed that stem cell treatment had a significant effect on increasing blood vessel density (SMD: 2.96, 95% CI 2.21 to 3.72) and increasing the expression of vascular endothelial growth factor (VEGF, SMD: 4.34, 95% CI 2.48 to 6.1). CONCLUSIONS: The preclinical evidence of our systematic review indicate that stem cell-based therapy is effective for promoting early angiogenesis by up regulating VEGF and ultimately improving the survival rate of skin flap. In summary, small area skin flap, the administration method of intra-arterial injection, ASCs and MSCs, and xenogenic stem cells from humans showed more effective for the survival of animal skin flaps. In general, stem cell-based therapy may be a promising method to prevent skin flap necrosis.