Preliminary study on mesenchymal stem cells in repairing nerve injury in pelvic floor denervation

Introduction: Nerve injury is considered one of the causes of pelvic floor dysfunction. Mesenchymal stem cells (MSCs) transplantation provides new possibilities for refractory degenerative diseases. This study aimed to explore the possibility and strategy of mesenchymal stem cells in treating pelvic floor dysfunction nerve injury.Methods: MSCs were isolated from human adipose tissue and cultured. A MSCs suspension (40 µL at 5 × 107/mL) was loaded on a gelatin scaffold. A rat model of anterior vaginal wall nerve injury was established by bilateral pudendal nerve denervation. The nerve tissue repair effect of mesenchymal stem cells transplanted into the anterior vaginal wall of a rat model was explored and compared in the following three groups: blank gelatin scaffold group (GS group), mesenchymal stem cell injection group (MSC group), and mesenchymal stem cells loaded on the gelatin scaffold group (MSC-GS group). Nerve fiber counting under a microscope and mRNA expression of neural markers were tested. Moreover, mesenchymal stem cells were induced into neural stem cells in vitro, and their therapeutic effect was explored.Results: Rat models of anterior vaginal wall nerve injury induced by bilateral pudendal nerve denervation showed a decreased number of nerve fibers in the anterior vaginal wall. qRT-PCR revealed that the content of neurons and nerve fibers in the rat model began to decrease 1 week after the operation and this could continue for 3 months. In vivo experiments showed that MSC transplantation improved the nerve content, and MSCs loaded on the gelatin scaffold had an even better effect. mRNA expression analysis demonstrated that MSCs loaded on gelatin scaffolds induced a higher and earlier gene expression of neuron-related markers. Induced neural stem cell transplantation was superior in improving the nerve content and upregulating the mRNA expression of neuron-related markers in the early stage.Conclusion: MSCs transplantation showed a promising repair capacity for nerve damage in the pelvic floor. The supporting role of gelatin scaffolds might promote and strengthen the nerve repair ability at an early stage. Preinduction schemes could provide an improved regenerative medicine strategy for innervation recovery and functional restoration in pelvic floor disorders in the future

Gate-tunable Topological Valley Transport in Bilayer Graphene

Valley pseudospin, the quantum degree of freedom characterizing the degenerate valleys in energy bands, is a distinct feature of two-dimensional Dirac materials. Similar to spin, the valley pseudospin is spanned by a time reversal pair of states, though the two valley pseudospin states transform to each other under spatial inversion. The breaking of inversion symmetry induces various valley-contrasted physical properties; for instance, valley-dependent topological transport is of both scientific and technological interests. Bilayer graphene (BLG) is a unique system whose intrinsic inversion symmetry can be controllably broken by a perpendicular electric field, offering a rare possibility for continuously tunable valley-topological transport. Here, we used a perpendicular gate electric field to break the inversion symmetry in BLG, and a giant nonlocal response was observed as a result of the topological transport of the valley pseudospin. We further showed that the valley transport is fully tunable by external gates, and that the nonlocal signal persists up to room temperature and over long distances. These observations challenge contemporary understanding of topological transport in a gapped system, and the robust topological transport may lead to future valleytronic applications

Application and performance evaluation of desulfurization wastewater spray drying technology

In order to realize zero discharge of desulfurization wastewater, spray drying technology of desulfurization wastewater was used in 2x330MW unit of a power plant. Its principle was to use a rotary atomizer for atomization,and a part of hot flue gas was drawn from the SCR denitrification reactor and air preheater into the drying tower, the heat was used to evaporate the desulfurization wastewater in a spray drying tower. The salt in the waste water was mixed with the dust, which was collected and removed by the electric dust remover. Then the water vapor was mixed with the flue gas and finally enters the desulfurization tower.The field test was carried out under the condition that the unit load was 100% and the amount of desulfurization wastewater treated was 5.1m3/h.The results showed that the hot smoke gas volume of drying tower was about 64896m3/h, The smoke temperature at the inlet and outlet of the drying tower were 335℃ and 205℃ respectively,the moisture content of drying products was only 0.05%. The content of HCl in the flue gas at the inlet and outlet of the drying tower were 55mg/L and 195mg/L respectively, the mass fractions of Cl removal and Cl volatilization in desulfurization wastewater were 87.7% and 12.3% respectively. The increase of Cl content in the dried products had little effect on the utilization of fly ash

Fault Diagnosis of Universal Circuit Breakers Based on Variational Mode Decomposition and WOA-DBN

Universal circuit breakers are crucial devices in power systems, and the accuracy of their fault diagnosis is vital. However, existing diagnostic models suffer from low feature extraction rates and low diagnostic accuracy. In this paper, we propose a novel approach for fault diagnosis of universal circuit breakers based on analyzing vibration signals generated during the closing operation. Firstly, the vibration signal was decomposed into multiple modal components using Variable Mode Decomposition (VMD), and the modal components were subjected to time and frequency domain feature extraction. Then, the extracted features were fused and normalized to construct a training dataset for the proposed model. We propose a Deep Belief Network (DBN) diagnostic model based on the Whale Optimization Algorithm (WOA), where the WOA is employed to optimize the hyperparameters of the DBN. Experimental results demonstrate that the proposed VMD and WOA-DBN model achieved an average accuracy of 96.63%. This method enhanced the accuracy of feature extraction from vibration signals and outperformed traditional diagnostic models when using a single vibration signal for fault diagnosis of universal circuit breakers. It provides a novel solution for early fault diagnosis of universal circuit breakers

Impact of DNA Extraction Methods on Quantitative PCR Telomere Length Assay Precision in Human Saliva Samples

Telomere length (TL) has emerged as a promising replicative cellular aging marker that reflects both genetic and non-genetic influences. Quantitative PCR (qPCR) TL measurement has been favored as a cost-effective method that can be easily implemented, especially in population studies with limited quantities of source material. However, several recent reports have revealed inconsistencies in telomere length measurements when applying different DNA extraction methods to the same source material. In this study we tested three DNA extraction methods on saliva samples from 48 participants of the National Growth and Health Study (NGHS) collected with DNA Genotek’s Oragene kit. The chosen extraction kits represent three distinct approaches to genomic DNA extraction from lysed cells and we employed two different operators to carry out all assays on the same samples. We measured DNA yield and quality and calculated the between-operator agreement of qPCR TL measurements (intraclass correlation, ICC). Our analyses showed that while both QIAamp and Agencourt DNAdvance had higher agreement between the 2 operators (ICC=0.937, CI [0.891, 0.965] and ICC=0.95, CI [0.911, 0.972] respectively), compared to PrepIT kit (ICC=0.809, CI [0.678, 0.889]), QIAamp extracted DNA samples were notably degraded. Using generalizability theory, we found that the participant-by-extraction-method interaction explained about 10% of total variation in TL, suggesting that TL differences across methods are somewhat participant-specific. Therefore, our results suggest that the among the three DNA extraction methods tested, Agencourt (magnetic bead purification) is the preferred kit, and we also strongly recommend against combining different extraction methods within a study population

Impact of DNA Extraction Methods on Quantitative PCR Telomere Length Assay Precision in Human Saliva Samples

Telomere length (TL) has emerged as a promising replicative cellular aging marker that reflects both genetic and non-genetic influences. Quantitative PCR (qPCR) TL measurement has been favored as a cost-effective method that can be easily implemented, especially in population studies with limited quantities of source material. However, several recent reports have revealed inconsistencies in telomere length measurements when applying different DNA extraction methods to the same source material. In this study we tested three DNA extraction methods on saliva samples from 48 participants of the National Growth and Health Study (NGHS) collected with DNA Genotek’s Oragene kit. The chosen extraction kits represent three distinct approaches to genomic DNA extraction from lysed cells and we employed two different operators to carry out all assays on the same samples. We measured DNA yield and quality and calculated the between-operator agreement of qPCR TL measurements (intraclass correlation, ICC). Our analyses showed that while both QIAamp and Agencourt DNAdvance had higher agreement between the 2 operators (ICC=0.937, CI [0.891, 0.965] and ICC=0.95, CI [0.911, 0.972] respectively), compared to PrepIT kit (ICC=0.809, CI [0.678, 0.889]), QIAamp extracted DNA samples were notably degraded. Using generalizability theory, we found that the participant-by-extraction-method interaction explained about 10% of total variation in TL, suggesting that TL differences across methods are somewhat participant-specific. Therefore, our results suggest that the among the three DNA extraction methods tested, Agencourt (magnetic bead purification) is the preferred kit, and we also strongly recommend against combining different extraction methods within a study population

Tuning the Interfacial Mechanical Behaviors of Monolayer Graphene/PMMA Nanocomposites

The van der Waals (vdW) force dominated interface between graphene and polymer matrix creates weak points in the mechanical sense. Chemical functionalization was expected to be an effective approach in transfer of the outstanding performance of graphene across multiple length scales up to the macroscopic level, due to possible improvements in the interfacial adhesion. However, published works showed the contradiction that improvements, insensitivity, or even worsening of macro-mechanical performance have all been reported in graphene-based polymer nanocomposites. Particularly central cause of such discrepancy is the variations in graphene/polymer interfacial chemistry, which is critical in nanocomposites with vast interfacial area. Herein, O₃/H₂O gaseous mixture was utilized to oxidize monolayer graphene sheet with controlled functionalization degrees. Hydrogen bonds (H bonds) are expected to form between oxidized graphene sheet/poly­(methyl methacrylate) (PMMA) at the interface. On the basis of in situ tensile-micro Raman spectroscopy, the impacts of bonding types (vdW and H-bonds) on both key interfacial parameters (such as interfacial shear strength and critical length) and failure modes of graphene/PMMA nanocomposite were clarified for the first time at the microscopic level. Our results show that owing to improved interfacial interaction via H bonds, the interface tends to be stiffening and strengthening. Moreover, the mechanical properties of the functionalized graphene/PMMA interface will be set by the competition between the enhanced interfacial adhesion and the degraded elastic modulus of graphene, which was caused by structural defects in the graphene sheet during the functionalization process and could lead to catastrophic failure of graphene sheets in our experimental observation. Our results will be helpful to design various nanofiller-based nanocomposites with high mechanical performance

Out-of-Plane Deformations Determined Mechanics of Vanadium Disulfide (VS2) Sheets

The rapid development of two-dimensional (2D) materials has significantly broadened the scope of 2D science in both fundamental scientific interests and emerging technological applications, wherein the mechanical properties play an indispensably key role. Nevertheless, particularly challenging is the ultrathin nature of 2D materials that makes their manipulations and characterizations considerably difficult. Herein, thanks to the excellent flexibility of vanadium disulfide (VS2) sheets, their susceptibility to out-of-plane deformation is exploited to realize the controllable loading and enable the accurate measurements of mechanical properties. In particular, the Young's modulus is estimated to be 44.4 +/- 3.5 GPa, approaching the lower limit for 2D transition metal dichalcogenides (TMDs). We further report the first measurement of thickness-dependent bending rigidity of VS2, which deviates from the prediction of the classical continuum mechanics theory. Additionally, a deeper understanding of the mechanics within two dimensions also facilitates the modulation of strain-coupled physics at the nanoscale. Our Raman measurements showed the Gruneisen parameters for VS2 were determined for the first time to be gamma(E2g1) approximate to 0.83 and gamma(A1g) approximate to 0.32