18 research outputs found

    Digital Assessment of the Implantation Angle of Proximal Femoral Nail Antirotation Helical Blade Using CT Three-dimensional Reconstruction

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    Objectives: To facilitate simple and safe manipulation during proximal femoral nail antirotation (PFNA) operation, we studied the range of safe implantation angle of the helical blade of the PFNA system by using a digital-based three-dimensional reconstruction model of CT images. Methods: Thirty-five healthy volunteers were recruited. Original multilayer helical CT scan data of the left femur were collected and imported into Mimics software. Anatomic features of the femur, including the safe implantation angle, anterior and posterior angle, were measured. Differences in each angle between male and female subjects were compared using Student's t test, and the determinants of each angle were analyzed by linear regression. Results: The mean safe implantation angle was 30.09° ± 4.73°, the mean anterior angle was 15.82° ± 2.07°, and the mean posterior angle was 14.27° ± 3.19°. All the three angles were greater in males than females (P < 0.05). Neck shaft angle and the diameter of the femoral neck and head were linearly correlated with the safe implantation angle, the anterior and posterior angle, respectively. Femoral neck diameter was a significant determinant of the safe implantation angle and posterior angle, respectively. Moreover, femoral neck diameter and femoral head diameter were significant determinants of the anterior angle. Conclusions: The study has introduced and delineated a novel parameter, the safe implantation angle, for FPNA surgery, which may help orthopedic surgeons in deciding a safe range of PFNA operation and improve the accuracy of PFNA helical blade implantation

    Warmer winters are reducing potential ice roads and port accessibility in the Pan-Arctic

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    Transportation in the Pan-Arctic winter is highly dependent on ice roads, which are affected by surface air temperatures and snow cover. In the context of polar increased warming, there is an urgent need to quantify the uncertainties of ice roads and their contribution to terrestrial transport. We evaluated the spatiotemporal characteristics of potential ice road changes by calculating four indicators: potential ice road area (PIRA), potential ice road days (PIRDs), potential ice road onset date (PIROD), and potential ice road end date (PIRED) from October to May, 1979–2017. Taking port accessibility as an example, we constructed a port accessibility model to quantify the contribution of potential ice roads to terrestrial transport. All four indicators showed significant ( p < 0.05) reductions in potential ice roads. PIRA experienced the largest share of losses in May (∼25%) and the sharpest reductions in April (2.77 × 10 ^4 km ^2 yr ^−1 ). PIRDs were shortened by an average of 0.41 d yr ^−1 , and delayed PIROD (0.28 d yr ^−1 on average) was more severe than advanced PIRED (0.21 d yr ^−1 on average). A stability analysis showed that potential ice roads were changing from suitable to unsuitable during November to May. Between December and April, potential ice roads can increase port accessibility by more than 24 h in Canadian Arctic and Siberia and by more than 9 h in Alaska. However, the contribution of potential ice roads has reduced over the past decades, especially in Nunavut. The results provide insights into changes in potential ice roads in the Pan-Arctic and suggest that remote land accessibility has decreased significantly with warmer winters

    Synthesis of Half-Titanocene Complexes Containing π,π-Stacked Aryloxide Ligands, and Their Use as Catalysts for Ethylene (Co)polymerizations

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    A family of half-titanocene complexes bearing π,π-stacked aryloxide ligands and their catalytic performances towards ethylene homo-/co- polymerizations were disclosed herein. All the complexes were well characterized, and the intermolecular π,π-stacking interactions could be clearly identified from single crystal X-ray analysis, in which a stronger interaction could be reflected for aryloxides bearing bigger π-systems, e.g., pyrenoxide. Due to the formation of such interactions, these complexes were able to highly catalyze the ethylene homopolymerizations and copolymerization with 1-hexene comonomer, even without any additiveson the aryloxide group, which showed striking contrast to other half-titanocene analogues, implying the positive influence of π,π-stacking interaction in enhancing the catalytic performances of the corresponding catalysts. Moreover, it was found that addition of external pyrene molecules was capable of boosting the catalytic efficiency significantly, due to the formation of a stronger π,π-stacking interaction between the complexes and pyrene molecules

    Ursolic Acid Inhibits Cigarette Smoke Extract-Induced Human Bronchial Epithelial Cell Injury and Prevents Development of Lung Cancer

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    Cigarette smoking is the main cause of chronic obstructive pulmonary disease and lung cancer. The present study was aimed to explore the chemopreventive effect of ursolic acid (UA) on these diseases. In the CSE treated normal human bronchial epithelial cell model, UA alleviated cytotoxicity caused by CSE, recovered the intracellular redox balance, and relieved the stimulation of external deleterious factors as well. UA mitigated CSE-induced DNA damage through the Nrf2 (nuclear factor erythroid 2-related factor 2) pathway. Moreover, UA inhibited lung cancer development in the model established by A549 cells in nude mice &lt;em&gt;in vivo&lt;/em&gt;. For the first time, our results indicate that UA could be developed as a potential lung cancer chemopreventive agent

    Moderating effect of salidroside on intestinal microbiota in mice exposed to PM2.5

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    BackgroundSalidroside (SAL) has a protective effect on multiple organ systems. Exposure to fine particulate matter (PM2.5) in the atmosphere may lead to disruptions in gut microbiota and impact intestinal health. The regulatory effect of SAL on the gut microbiota of mice exposed to PM2.5 requires further investigation.ObjectiveTo evaluate gut microbiota disruption in mice after being exposed to PM2.5 and the potential effect of SAL.MethodsForty male C57BL/6 mice, aged 6 to 8 weeks, were randomly divided into four groups: a control group, an SAL group, a PM2.5 group, and an SAL+PM2.5 group, each containing 10 mice. In the SAL group and the SAL+PM2.5 group, the mice were administered SAL (60 mg·kg−1) by gavage, while in the control group and the PM2.5 group, sterile saline (10 mL·kg−1) was administered by gavage. In the PM2.5 group and the SAL+PM2.5 group, PM2.5 suspension (8 mg·kg−1) was intratracheally instilled, and in the control group and SAL group, sterile saline (1.5 mL·kg−1) was intratracheally administered. Each experiment cycle spanned 2 d, with a total of 10 cycles conducted over 20 d. Histopathological changes in the ileum tissue of the mice were observed after HE staining. Colon contents were collected for gut microbiota sequencing and short-chain fatty acids (SCFAs) measurements.ResultsThe PM2.5 group showed infiltration of inflammatory cells in the ileum tissue, while the SAL+PM2.5 group exhibited only a small amount of inflammatory cell infiltration. Compared to the control group, the PM2.5 group showed decreased Shannon index (P<0.05) and increased Simpson index (P<0.05), indicating that the diversity of gut microbiota in this group was decreased; the SAL+PM2.5 group showed increased Shannon index compared to the PM2.5 group (P<0.05) and decreased Simpson index (P<0.05), indicating that the diversity of gut microbiota in mice intervened with SAL was increased. The principal coordinates analysis (PCoA) revealed a significant separation between the PM2.5 group and the control group, while the separation trend was less evident among the control group, the SAL group, and the SAL+PM2.5 group. The unweighted pair-group method with arithmetic means (UPGMA) clustering tree results showed that the control group and the SAL group clustered together first, followed by clustering with the SAL+PM2.5 group, and finally, the three groups clustered with the PM2.5 group. The PCoA and UPGMA clustering results indicated that the uniformity and similarity of the microbiota in the PM2.5 group were significantly decreased. Compared to the control group, the PM2.5 group showed decreased abundance of phylum Bacteroidetes and Candidatus_Saccharimonas (P<0.05) and increased abundance of phylum Proteobacteria, genus Escherichia, genus Bacteroides, genus Prevotella, genus Enterococcus, and genus Proteus (P<0.05). Compared to the PM2.5 group, the SAL+PM2.5 group showed decreased abundance of phylum Proteobacteria, phylum Actinobacteria, genus Prevotella, and genus Proteus (P<0.05), and increased abundance of Candidatus_Saccharimonas (P<0.05). The PM2.5 group showed reduced levels of propionic acid, valeric acid, and hexanoic acid compared to the control group (P<0.05), while the SAL+PM2.5 group showed increased levels of propionic acid, isobutyric acid, butyric acid, valeric acid, and hexanoic acid compared to the PM2.5 group (P<0.05).ConclusionExposure to PM2.5 can cause pathological alterations, microbial dysbiosis, and disturbing production of SCFAs in intestinal tissue in mice. However, SAL can provide a certain degree of protective effect against these changes

    The Anti-Warburg Effect Elicited by the cAMP-PGC1α Pathway Drives Differentiation of Glioblastoma Cells into Astrocytes

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    Summary: Glioblastoma multiforme (GBM) is among the most aggressive of human cancers. Although differentiation therapy has been proposed as a potential approach to treat GBM, the mechanisms of induced differentiation remain poorly defined. Here, we established an induced differentiation model of GBM using cAMP activators that specifically directed GBM differentiation into astroglia. Transcriptomic and proteomic analyses revealed that oxidative phosphorylation and mitochondrial biogenesis are involved in induced differentiation of GBM. Dibutyryl cyclic AMP (dbcAMP) reverses the Warburg effect, as evidenced by increased oxygen consumption and reduced lactate production. Mitochondrial biogenesis induced by activation of the CREB-PGC1α pathway triggers metabolic shift and differentiation. Blocking mitochondrial biogenesis using mdivi1 or by silencing PGC1α abrogates differentiation; conversely, overexpression of PGC1α elicits differentiation. In GBM xenograft models and patient-derived GBM samples, cAMP activators also induce tumor growth inhibition and differentiation. Our data show that mitochondrial biogenesis and metabolic switch to oxidative phosphorylation drive the differentiation of tumor cells. : Xing et al. show that the metabolic shift from glycolysis to oxidative phosphorylation drives differentiation of GBM cells into astrocytes by cAMP activation. Mechanistically, the cAMP-CREB-PGC1α signal mediates mitochondrial biogenesis, which leads to metabolic reprogramming, induced differentiation, and tumor growth inhibition. Keywords: glioblastoma, induced differentiation, Warburg effect, metabolic reprogramming, oxidative phosphorylation, glycolysis, mitochondrial biogenesis, cyclic adenosine monophosphate, cAMP, PPARγ coactivator-1α, PGC1
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