Deterioration of Mechanical Properties of Axial Compression Concrete Columns with Corroded Stirrups Coupling on Load and Chloride

To research the deterioration of the mechanical properties of stirrup-corroded concrete columns under the effect of load and chloride, accelerated corrosion and load carrying capacity tests were carried out on concrete columns subjected to long-term axial loading by means of dry and wet cycles with extra electric currents. The test results showed that under the effect of axial load and chloride, the corrosion-induced cracks of stirrup-corroded concrete columns mainly developed along the direction of the longitudinal reinforcing steel bars (cracks along longitudinal reinforcing steel bars caused by corrosion) and there were almost no corrosion-induced cracks along the direction of the corroded stirrups. The length and maximum width of the corrosion-induced cracks increased with the stirrup corrosion rate, but the average width of the corrosion-induced cracks did not change significantly. After the stirrup-corroded column reached the ultimate load, the concrete cover spalled off in pieces along the corrosion-induced cracks and loading cracks, the core concrete was crushed, and the test column produced obvious brittle failure. With the increase in the corrosion rate of stirrups, the stiffness and ultimate bearing capacity of the column decreased. Considering factors such as damage to the column section caused by stirrup corrosion, the decrease in the lateral restraint effect of the corroded stirrup on the longitudinal reinforcing steel bars, and buckling of the longitudinal reinforcing steel bars, the ultimate bearing capacity prediction model of the short column subjected to axial compression due to stirrup corrosion was established. The calculated values of the model were in good agreement with the measured values, indicating the model has good applicability

IDH1 R132H Mutation Enhances Cell Migration by Activating AKT-mTOR Signaling Pathway, but Sensitizes Cells to 5-FU Treatment as NADPH and GSH Are Reduced.

Mutations of isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) gene were recently discovered in vast majority of World Health Organization (WHO) grade II/III gliomas. This study is to understand the effects of IDH1 R132H mutation in gliomagenesis and to develop new strategies to treat glioma with IDH1 R132H mutation.Over expression of IDH1 R132H in U87MG cells was done by transfecting cells with IDH1 R132H plasmid. MTT assay, scratch repair assay and western blot were performed to study effects of IDH1 R132H mutation on cell proliferation, migration, regulating AKT-mTOR signaling pathway and cell death respectively. NADP+/NADPH and GSH quantification assays were performed to evaluate effects of IDH1 R132H mutation on the production of antioxidant NADPH and GSH.We found that over expression of IDH1 R132H mutation decreased cell proliferation consistent with previous reports; however, it increased cell migration and enhanced AKT-mTOR signaling pathway activation. Mutations in isocitrate dehydrogenase (IDH) 1 also change the function of the enzymes and cause them to produce 2-hydroxyglutarate and not produce NADPH. We tested the level of NADPH and GSH and demonstrated that IDH1 R132H mutant stable cells had significantly low NADPH and GSH level compared to control or IDH1 wild type stable cells. The reduced antioxidants (NADPH and GSH) sensitized U87MG cells with IDH R132H mutant to 5-FU treatment.Our study highlights the important role of IHD1 R132H mutant in up- regulating AKT-mTOR signaling pathway and enhancing cell migration. Furthermore, we demonstrate that IDH1 R132H mutation affects cellular redox status and sensitizes gliomas cells with IDH1 R132H mutation to 5FU treatment

A Randomized Study of Rigid Video Stylet versus Macintosh Laryngoscope for Double-Lumen Endobronchial Tube Intubation Assistance in Thoracoscopic Pulmonary Surgery

Double-lumen endobronchial tube (DLT) intubation is more challenging than single-lumen tube intubation is, and the rigid video stylet (RVS) is one of the tools that has emerged to deal with this demanding intubation procedure. We evaluated whether the UE® RVS can shorten the DLT intubation time and improve the first-attempt intubation success rate compared with that of Macintosh laryngoscope (ML). A total of 130 participants scheduled to undergo thoracoscopic pulmonary surgeries were enrolled. They were randomized to receive either ML- or RVS-assisted DLT intubation. The primary outcomes were the intubation time and first-attempt intubation success rate. The secondary outcomes were the overall intubation success rate, mean arterial pressure, postoperative sore throat (POST), and postoperative hoarseness at 1 h and 24 h. Compared with the ML group, the intubation time was significantly shorter in the RVS group (p p = 0.048; 83.08% vs. 95.16%). The POST at 1 h was less severe in the RVS group (p = 0.021). No significant differences were found for the other indicators. Among the patients with normal airways, the UE® RVS can achieve faster DLT intubation and decrease the severity of a POST at 1 h, although it was associated with a lower first-attempt intubation success rate

CcpA Regulates <i>Staphylococcus aureus</i> Biofilm Formation through Direct Repression of Staphylokinase Expression

Staphylococcus aureus represents a notorious opportunistic pathogen causing various infections in biofilm nature, imposing remarkable therapeutic challenges worldwide. The catabolite control protein A (CcpA), a major regulator of carbon catabolite repression (CCR), has been recognized to modulate S. aureus biofilm formation, while the underlying mechanism remains to be fully elucidated. In this study, the reduced biofilm was firstly determined in the ccpA deletion mutant of S. aureus clinical isolate XN108 using both crystal violet staining and confocal laser scanning microscopy. RNA-seq analysis suggested that sak-encoding staphylokinase (Sak) was significantly upregulated in the mutant ∆ccpA, which was further confirmed by RT-qPCR. Consistently, the induced Sak production correlated the elevated promoter activity of sak and increased secretion in the supernatants, as demonstrated by Psak-lacZ reporter fusion expression and chromogenic detection, respectively. Notably, electrophoretic mobility shift assays showed that purified recombinant protein CcpA binds directly to the promoter region of sak, suggesting the direct negative control of sak expression by CcpA. Double isogenic deletion of ccpA and sak restored biofilm formation for mutant ∆ccpA, which could be diminished by trans-complemented sak. Furthermore, the exogenous addition of recombinant Sak inhibited biofilm formation for XN108 in a dose-dependent manner. Together, this study delineates a novel model of CcpA-controlled S. aureus biofilm through direct inhibition of sak expression, highlighting the multifaceted roles and multiple networks regulated by CcpA

siRNA IDH1 decreased cell proliferation and migration.

<p>A. Western blotting performed to detect levels of IDH1 in control and SiRNA-IDH1 cells. B. The rate of proliferation of parental U87MG, siRNA-IDH1 cells. (p<0.05). C. Images of parental U87MG, siRNA-IDH1 cells taken at 0 and 48 hours after scratch assay. D. Migration index was used to quantify the cell migration. Control cells vs.siRNA-IDH1 cells. (p<0.05).</p

IDH1 R132H mutant stable cells have increased activation of AKT-mTOR signaling pathway, while knocking down IDH1 inhibited AKT-mTOR activation.

<p>A. Western blotting was performed to detect activated P-AKT and p-mTOR, total AKT and mTOR in stable cells overexpressing vector, IDH1 R132H mutant or IDH1 wild type. B. Quantification of p-AKT/total AKT, p-mTOR/total mTOR. p-AKT/total AKT and p-mTOR/total mTOR in R132H mutant stable cells vs. control or IDH1 wild type stable cells (p<0.05). C. P-AKT and p-mTOR, total AKT and mTOR were detected in control cells and cells transfected with siRNA targeting IDH1. D. Quantification of p-AKT/total AKT, p-mTOR/total mTOR. p-AKT/total AKT and p-mTOR/total mTOR in Control vs. SiRNA-IDH1 (p<0.05).</p

IDH1 R132H mutant stable cells have decreased NADPH and GSH.

<p>A. NDAPH level detected in control cells, IDH1 wild type stable cells and IDH1 R132H mutant stable cells. IDH1 R132H mutant vs. control (P<0.05). B. GSH level detected in control cells, IDH1 wild type stable cells and IDH1 R132H mutant stable cells. IDH1 R132H mutant vs. control vs. IDH1 wild type (p<0.05).</p

Over expression of IDH1 R132H mutant but not IDH1 wild type decreased cell proliferation.

<p>The rate of proliferation of parental U87MG, vector control stable cells, IDH1 wild type and IDH1 R132H stable cells were examined using MTT assay. IDH1 R132H mutant stable cells vs. parental control, vs. empty vector stable cells. (p<0.05).</p