Biomechanical analysis of sandwich vertebrae in osteoporotic patients: finite element analysis

ObjectiveThe aim of this study was to investigate the biomechanical stress of sandwich vertebrae (SVs) and common adjacent vertebrae in different degrees of spinal mobility in daily life.Materials and methodsA finite element model of the spinal segment of T10-L2 was developed and validated. Simultaneously, T11 and L1 fractures were simulated, and a 6-ml bone cement was constructed in their center. Under the condition of applying a 500-N axial load to the upper surface of T10 and immobilizing the lower surface of L2, moments were applied to the upper surface of T10, T11, T12, L1, and L2 and divided into five groups: M-T10, M-T11, M-T12, M-L1, and M-L2. The maximum von Mises stress of T10, T12, and L2 in different groups was calculated and analyzed.ResultsThe maximum von Mises stress of T10 in the M-T10 group was 30.68 MPa, 36.13 MPa, 34.27 MPa, 33.43 MPa, 26.86 MPa, and 27.70 MPa greater than the maximum stress value of T10 in the other groups in six directions of load flexion, extension, left and right lateral bending, and left and right rotation, respectively. The T12 stress value in the M-T12 group was 29.62 MPa, 32.63 MPa, 30.03 MPa, 31.25 MPa, 26.38 MPa, and 26.25 MPa greater than the T12 stress value in the other groups in six directions. The maximum stress of L2 in M-T12 in the M-L2 group was 25.48 MPa, 36.38 MPa, 31.99 MPa, 31.07 MPa, 30.36 MPa, and 32.07 MPa, which was greater than the stress value of L2 in the other groups. When the load is on which vertebral body, it is subjected to the greatest stress.ConclusionWe found that SVs did not always experience the highest stress. The most stressed vertebrae vary with the degree of curvature of the spine. Patients should be encouraged to avoid the same spinal curvature posture for a long time in life and work or to wear a spinal brace for protection after surgery, which can avoid long-term overload on a specific spine and disrupt its blood supply, resulting in more severe loss of spinal quality and increasing the possibility of fractures

Mudskipper genomes provide insights into the terrestrial adaptation of amphibious fishes

Mudskippers are amphibious fishes that have developed morphological and physiological adaptations to match their unique lifestyles. Here we perform whole-genome sequencing of four representative mudskippers to elucidate the molecular mechanisms underlying these adaptations. We discover an expansion of innate immune system genes in the mudskippers that may provide defence against terrestrial pathogens. Several genes of the ammonia excretion pathway in the gills have experienced positive selection, suggesting their important roles in mudskippers’ tolerance to environmental ammonia. Some vision-related genes are differentially lost or mutated, illustrating genomic changes associated with aerial vision. Transcriptomic analyses of mudskippers exposed to air highlight regulatory pathways that are up- or down-regulated in response to hypoxia. The present study provides a valuable resource for understanding the molecular mechanisms underlying water-to-land transition of vertebrates

Regular Analysis of Aero-Diesel Piston Engine between Combustion Chamber Size and Emission

The emission of aero-engines has been a focused issue, studying the regular of combustion chamber size on engine emission performance, with an aviation diesel piston engine as the object of study; the numerical model of diesel combustion spray and emission model are analyzed; and the dynamics grid of the combustion chamber is meshed by FIRE software, analyzing the relationship between the reentrant diameter, the maximum depth of the combustion chamber, and the emission generation, comparing the NOx and soot emissions under different combustion chamber sizes. The results show that reducing appropriately the reentrant-max diameter ratio and max diameter-max depth ratio of the combustion chamber can reduce emissions when maintaining the same compression ratio by adjusting the mid-depth. Modifying the geometry parameters of the combustion chamber to verify regularity, it was found that engine NOx emission decreased by 28% and soot emission decreased by 3.6% when changing the size, which verified the correctness of regular analysis

Inventory and Distribution Characteristics of Large-Scale Landslides in Baoji City, Shaanxi Province, China

Inventories of historical landslides play an important role in the assessment of natural hazards. In this study, we used high-resolution satellite imagery from Google Earth to interpret large landslides in Baoji city, Shaanxi Province on the southwestern edge of the Loess Plateau. Then, a comprehensive and detailed map of the landslide distribution in this area was prepared in conjunction with the historical literature, which includes 3440 landslides. On this basis, eight variables, including elevation, slope, aspect, slope position, distance to the fault, land cover, lithology and distance to the stream were selected to examine their influence on the landslides in the study area. Landslide number density (LND) and landslide area percentage (LAP) were used as evaluation indicators to analyze the spatial distribution characteristics of the landslides. The results show that most of the landslides are situated at elevations from 500 to 1400 m. The LND and LAP reach their peaks at slopes of 10–20°. Slopes facing WNW and NW directions, and middle and lower slopes are more prone to sliding with higher LND and LAP. LND and LAP show a decreasing trend as the distance to the fault or stream increases, followed by a slow rise. Landslides occur primarily in the areas covered by crops. Regarding lithology, the regions covered by the Quaternary loess and Cretaceous gravels are the main areas where landslides occur. The results would be helpful for further understanding the developmental characteristics and spatial distribution of landslides on the Loess Plateau, and also provide a support to subsequent landslide susceptibility mapping in this region

Inventory and Distribution Characteristics of Large-Scale Landslides in Baoji City, Shaanxi Province, China

Inventories of historical landslides play an important role in the assessment of natural hazards. In this study, we used high-resolution satellite imagery from Google Earth to interpret large landslides in Baoji city, Shaanxi Province on the southwestern edge of the Loess Plateau. Then, a comprehensive and detailed map of the landslide distribution in this area was prepared in conjunction with the historical literature, which includes 3440 landslides. On this basis, eight variables, including elevation, slope, aspect, slope position, distance to the fault, land cover, lithology and distance to the stream were selected to examine their influence on the landslides in the study area. Landslide number density (LND) and landslide area percentage (LAP) were used as evaluation indicators to analyze the spatial distribution characteristics of the landslides. The results show that most of the landslides are situated at elevations from 500 to 1400 m. The LND and LAP reach their peaks at slopes of 10–20°. Slopes facing WNW and NW directions, and middle and lower slopes are more prone to sliding with higher LND and LAP. LND and LAP show a decreasing trend as the distance to the fault or stream increases, followed by a slow rise. Landslides occur primarily in the areas covered by crops. Regarding lithology, the regions covered by the Quaternary loess and Cretaceous gravels are the main areas where landslides occur. The results would be helpful for further understanding the developmental characteristics and spatial distribution of landslides on the Loess Plateau, and also provide a support to subsequent landslide susceptibility mapping in this region

Matrine induces cell cycle arrest and apoptosis in hepatocellular carcinoma cells via miR-122 mediated CG1/livin/survivin signal axis

Purpose: To study the impact of matrine on cell cycle and apoptotic changes in hepatoma cells, and the mechanism involved. Methods: Human hepatoma cell line HepG2 was treated with different concentrations of matrine. The blank control cells were maintained in 1640 medium only. The influence of matrine on proliferative ability was determined with 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) method. Flow cytometry was used to determine its effect on cell cycle and apoptosis; RT-PCR (reverse transcription-polymerase chain reaction) was applied to assay the mRNA expressions of miR-122, cyclin G1 (CG1), livin and survivin mRNA, while the protein expressions of CG1, livin and surviving were assayed by Western blotting. Results: Matrine time- and dose-dependently suppressed the proliferative capacity of the cells. At a concentration of 0.5 mg/mL, matrine had no significant effect on the cell cycle. However, 1.0 mg/mL matrine blocked the cell cycle in G1 phase, while 1.5 mg/mL matrine blocked HepG2 cells in G2/M phase (p < 0.05). Moreover, matrine induced apoptosis in HepG2 cells, and markedly downregulated the expressions of miR-122 concentration- time-reliantly (p < 0.05). In addition, matrine markedly and concentration-dependently reduced mRNA and protein expression levels of CG1, livin and survivin, with the strongest inhibitory effect at a level of 1.5 mg/mL. Conclusion: Matrine induces cell cycle block and apoptotic changes in hepatoma cells through a mechanism related to regulation of the CG1/livin/survivin signal axis mediated by miR-122. Matrine may be a potential treatment for liver cancer. However, clinical trials are needed to confirm this potential

Advance and Challenges in the Treatment of Skin Diseases with the Transdermal Drug Delivery System

Skin diseases are among the most prevalent non-fatal conditions worldwide. The transdermal drug delivery system (TDDS) has emerged as a promising approach for treating skin diseases, owing to its numerous advantages such as high bioavailability, low systemic toxicity, and improved patient compliance. However, the effectiveness of the TDDS is hindered by several factors, including the barrier properties of the stratum corneum, the nature of the drug and carrier, and delivery conditions. In this paper, we provide an overview of the development of the TDDS from first-generation to fourth-generation systems, highlighting the characteristics of each carrier in terms of mechanism composition, penetration method, mechanism of action, and recent preclinical studies. We further investigated the significant challenges encountered in the development of the TDDS and the crucial significance of clinical trials

Efficient electrocatalytic oxygen evolution at extremely high current density over 3D ultrasmall zero-valent iron-coupled nickel sulfide nanosheets

Nonprecious water oxidation electrocatalysts that perform well at high current densities are among the key enabling drivers of renewable energy technologies. Herein, we report a novel strategy to produce 3D ultrasmall zero‐valent iron‐coupled nickel sulfides nanosheets (Fe0−NixSy) hybrid on self‐supported conductive Ni foam (denoted as Fe0−NixSy/NF) through a robust single‐step gas–solid reaction. In this 3D hybrid, the Fe0−NixSy nanosheets with a length of approximately 400 nm and an average thickness of 33 nm are uniformly grown on the Ni foam. Benefiting from the unique 3D hierarchical structure and synergistic effect between Fe0 and NixSy, the 3D Fe0−NixSy/NF hybrid shows an excellent electrocatalytic activity towards oxygen evolution reaction (OER) at extremely high current densities in basic media. The current densities of 1000 and 1500 mA cm−2 are achieved at low potentials of 1.57 and 1.60 V, respectively, thus meeting the expected OER standards for industrial applications. These overpotentials of the 3D Fe0−NixSy/NF hybrid are the lowest among all previously reported nickel‐sulfide‐based electrocatalysts, and are even superior compared to state‐of‐the‐art Ir/C catalysts. We further demonstrate that the integration of the 3D Fe0−NixSy/NF electrocatalyst as both anode and cathode with a silicon photovoltaic cell enables highly active and sustainable solar‐driven overall water splitting

Diversity and composition of bacterial endophytes among plant parts of Panax notoginseng

Abstract Background Bacterial endophytes are widespread inhabitants inside plant tissues that play crucial roles in plant growth and biotransformation. This study aimed to offer information for the exploitation of endophytes by analyzing the bacterial endophytes in different parts of Panax notoginseng. Methods We used high-throughput sequencing methods to analyze the diversity and composition of bacterial endophytes from different parts of P. notoginseng. Results A total of 174,761 classified sequences were obtained from the analysis of 16S ribosomal RNA in different parts of P. notoginseng. Its fibril displayed the highest diversity of bacterial endophytes. Principal coordinate analysis revealed that the compositions of the bacterial endophytes from aboveground parts (flower, leaf, and stem) differed from that of underground parts (root and fibril). The abundances of Conexibacter, Gemmatimonas, Holophaga, Luteolibacter, Methylophilus, Prosthecobacter, and Solirubrobacter were significantly higher in the aboveground parts than in the underground parts, whereas the abundances of Bradyrhizobium, Novosphingobium, Phenylobacterium, Sphingobium, and Steroidobacter were markedly lower in the aboveground parts. Conclusions Our results elucidated the comprehensive diversity and composition profiles of bacterial endophytes in different parts of 3-year-old P. notoginseng. Our data offered pivotal information to clarify the role of endophytes in the production of P. notoginseng and its important metabolites