The role of Cr content on the corrosion resistance of carbon steel and low-Cr steels in the CO_(2)-saturated brine

The selection of appropriate materials for the transportation pipelines is of vital importance to ensure the safety operation in Carbon Capture,Utilisation and Storage(CCUS).To clarify the effects of Cr content in steel on the resistance against general and localised corrosion,electrochemistry methods combined with pH measurements and various surface analysis techniques were implemented on X65,1Cr,3Cr and 5Cr steel samples in a CO_(2)-saturated solution at 60°C and pH 6.6 during 192 h of immersion.Additionally,thermodynamic and kinetic analyses of the formation of the corrosion products on carbon steel and low-Cr steels were performed.The results show that the general corrosion resistance increased with rising Cr content without the presence of significant corrosion products formation.However,with the formation and development of the corrosion products,the general corrosion resistance reduced with the increase in Cr content.The formation of the compact crystalline FeCO3 on X65 and 1Cr steel surfaces offered superior general corrosion protection,while cannot provide enough localised corrosion protection.By contrast,the double-structural corrosion product layers on 3Cr and 5Cr steels notably suppressed the localised corrosion,but providing poor protection against general corrosion over long immersion periods.This study reveals the contributions of Cr content on general and localised corrosion resistance at various periods,providing references for material selection and evaluation in CO_(2) environments relevant for CCUS.

Conditional survival probability of distant-metastatic hepatocellular carcinoma: A population-based study

BACKGROUND The prognosis of many patients with distant metastatic hepatocellular carcinoma(HCC)improved after they survived for several months.Compared with tradi-tional survival analysis,conditional survival(CS)which takes into account changes in survival risk could be used to describe dynamic survival probabilities.AIM To evaluate CS of distant metastatic HCC patients.METHODS Patients diagnosed with distant metastatic HCC between 2010 and 2015 were extracted from the Surveillance,Epidemiology and End Results database.Univariate and multivariate Cox regression analysis were used to identify factors for overall survival(OS),while competing risk model was used to identify risk factors for cancer-specific survival(CSS).Six-month CS was used to calculate the probability of survival for an additional 6 mo at a specific time after initial diagnosis,and standardized difference(d)was used to evaluate the survival differences between subgroups.Nomograms were constructed to predict CS.Positiveα-fetoprotein expression,higher T stage(T3 and T4),N1 stage,non-primary site surgery,non-chemotherapy,non-radiotherapy,and lung metastasis were independent risk factors for actual OS and CSS through univariate and multivariate analysis.Actual survival rates decreased over time,while CS rates gradually increased.As for the 6-month CS,the survival difference caused by chemotherapy and radiotherapy gradually disappeared over time,and the survival difference caused by lung metastasis reversed.Moreover,the influence of age and gender on survival gradually appeared.Nomograms were fitted for patients who have lived for 2,4 and 6 mo to predict 6-month conditional OS and CSS,respectively.The area under the curve(AUC)of nomograms for conditional OS decreased as time passed,and the AUC for conditional CSS gradually increased.CONCLUSION CS for distant metastatic HCC patients substantially increased over time.With dynamic risk factors,nomograms constructed at a specific time could predict more accurate survival rates.

A Comparative Study Between Tumor Blood Vessels and Dynamic Contrast-enhanced MRI for Identifying Isocitrate Dehydrogenase Gene 1(IDH1)Mutation Status in Glioma

Objective Isocitrate dehydrogenase gene(IDH)mutations are associated with tumor angiogenesis and therefore play an important role in glioma management.This study compared the performance of tumor blood vessels counted from contrast-enhanced 3D brain volume(3D-BRAVO)sequence and dynamic contrast-enhanced(DCE)MRI in differentiating IDH1 status in gliomas.Methods Forty-four glioma patients[16 with IDH1 mutant-type(IDH1-MT),28 with IDH1 wild-type(IDH1-WT)]were retrospectively analyzed.A blood vessel entering a tumor was defined as an intratumoral vessel;a blood vessel adjacent to the edge of a tumor was defined as a peritumoral vessel.Combined vessels were defined as the sum of the intratumoral and peritumoral vessels.DCE-derived metrics of tumor were normalized to the contralateral normal-appearing white matter.Results Intratumoral,peritumoral,and combined tumor blood vessels were all significantly different between IDH1-MT and IDH1-WT gliomas,and the range of area under curves(AUCs)was 0.816–0.855.For DCE-derived parameters,cerebral blood volume,cerebral blood flow,mean transit time,and volume transfer constant were significantly different between IDH1-MT and IDH1-WT gliomas,and the range of AUCs was 0.703–0.756.Combined vessels possessed the best performance for identifying IDH1 mutations in gliomas(AUC:0.855,sensitivity:0.857,specificity:0.812,P<0.001).Conclusion The number of tumor blood vessels has comparable diagnostic performance with DCE-derived parameters for differentiating IDH1 mutations and can serve as a potential imaging biomarker to reflect IDH1 mutations in gliomas.

Unexpected BrdU inhibition on astrocyte-to-neuron conversion

5-Bromo-2′-deoxyuridine(BrdU)is a halogenated pyrimidine that can be incorporated into newly synthesized DNA during the S phase of the cell cycle.BrdU is widely used in fate-mapping studies of embryonic and adult neurogenesis to identify newborn neurons,however side effects on neural stem cells and their progeny have been reported.In vivo astrocyte-to-neuron(AtN)conversion is a new approach for generating newborn neurons by directly converting endogenous astrocytes into neurons.The BrdU-labeling strategy has been used to trace astrocyte-converted neurons,but whether BrdU has any effect on the AtN conversion is unknown.Here,while conducting a NeuroD1-mediated AtN conversion study using BrdU to label dividing reactive astrocytes following ischemic injury,we accidentally discovered that BrdU inhibited AtN conversion.We initially found a gradual reduction in BrdU-labeled astrocytes during NeuroD1-mediated AtN conversion in the mouse cortex.Although most NeuroD1-infected astrocytes were converted into neurons,the number of BrdU-labeled neurons was surprisingly low.To exclude the possibility that this BrdU inhibition was caused by the ischemic injury,we conducted an in vitro AtN conversion study by overexpressing NeuroD1 in cultured cortical astrocytes in the presence or absence of BrdU.Surprisingly,we also found a significantly lower conversion rate and a smaller number of converted neurons in the BrdU-treated group compared with the untreated group.These results revealed an unexpected inhibitory effect of BrdU on AtN conversion,suggesting more caution is needed when using BrdU in AtN conversion studies and in data interpretation.

Numerical evaluation of segmental tunnel lining with voids in outside backfill

This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining.The composite lining was formed by mining outside and shield tunnelling inside with backfill in between.Finite element method was conducted to analyse the axial forces and bending moment for voids of different diameters at different positions.The results show that the axial forces in the transverse section increase near the crown and then invert and decrease on the left and right sides with an increase in the void centre angle(β)measured from the vertical axis.The increase in void diameter(d<300 mm)induces an increase in the axial force on the left and right sides when β=45°and 90°,while it decreases near the crown and invert.The occurrence of voids leads to an increase in the bending moment in the entire segment section with an angle β.