The sensitivity to ductility dip cracking was measured in two model high chromium nickel alloys, with the same composition, apart from different sulphur contents. The newly developed Refusion ...Cracking Test was used, that consists in repetitive refusion lines conducted at the specimen surface. Grain boundary cracks develop in the heat affected zone near the refusion line. Cracking is much more pronounced in the sulphur-enriched alloy, which demonstrates a strong deleterious effect of sulphur. However post-mortem analyses using WDS and STEM-EDS revealed no segregation of sulphur at grain boundaries. In contrast, grain boundary fracture surfaces are covered with sulphur. This suggests a dynamic type of grain boundary embrittlement where sulphur acts as a surfactant, facilitating crack opening. Sulphur is efficiently provided to the crack tip as it propagates, due to accelerated diffusion by plastic deformation. This allows crack growth rates higher than 10 µm/s.
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During operating lifetime of a nuclear power plant, the pressure boundary components, usually in 16MND5 (SA508 Cl. 3) steel, are subjected to thermal aging that may induce phosphorus intergranular ...segregation. This is known to decrease brittle fracture stress and induce intergranular fracture, which causes reversible temper embrittlement. Large components such as the reactor pressure vessel presents microstructure heterogeneity due to forging and welding. Tempered martensite can locally be found in the nominally bainitic steel. The question of microstructure susceptibility to reversible temper embrittlement has been raised in literature suggesting that tempered martensite has higher sensibility to phosphorus intergranular segregation than tempered bainite. In this paper, a comparative study of intergranular segregation in tempered bainitic and martensitic 16MND5 steel after thermal aging is conducted using energy dispersive X-ray spectroscopy on transmission electron microscope. Focus ion beam is used to precisely prepare lamellae at prior austenite grain boundaries on step cooled bainitic and martensitic samples. Different types of grain boundaries are identified using precession assisted crystal orientation mapping and then the local chemical composition is analyzed. Phosphorus, nickel, manganese and molybdenum were observed at all types of grain boundaries in both microstructures. The segregation levels are higher in prior austenitic grain boundaries than in other types of boundaries for both microstructures. Taking into account the segregation amount in different types of boundaries, the phosphorus bulk depletion is shown negligible. The results show similar segregation levels in the two studied microstructures, indicating that the susceptibility to thermally induced grain boundary segregation between the tempered bainite and tempered martensite is the same.
MicroRNAs (miRNAs) belong to a family of small non‐coding RNAs (sncRNAs) playing important roles in human carcinogenesis. Multiple investigations reported miRNAs aberrantly expressed in several ...cancers, including high‐grade serous ovarian carcinoma (HGS‐OvCa). Quantitative PCR is widely used in studies investigating miRNA expression and the identification of reliable endogenous controls is crucial for proper data normalization. In this study, we aimed to experimentally identify the most stable reference sncRNAs for normalization of miRNA qPCR expression data in HGS‐OvCa. Eleven putative reference sncRNAs for normalization (U6, SNORD48, miR‐92a‐3p, let‐7a‐5p, SNORD61, SNORD72, SNORD68, miR‐103a‐3p, miR‐423‐3p, miR‐191‐5p, miR‐16‐5p) were analysed on a total of 75 HGS‐OvCa and 30 normal tissues, using a highly specific qPCR. Both the normal tissues considered to initiate HGS‐OvCa malignant transformation, namely ovary and fallopian tube epithelia, were included in our study. Stability of candidate endogenous controls was evaluated using an equivalence test and validated by geNorm and NormFinder algorithms. Combining results from the three different statistical approaches, SNORD48 emerged as stably and equivalently expressed between malignant and normal tissues. Among malignant samples, considering groups based on residual tumour, miR‐191‐5p was identified as the most equivalent sncRNA. On the basis of our results, we support the use of SNORD48 as best reference sncRNA for relative quantification in miRNA expression studies between HGS‐OvCa and normal controls, including the first time both the normal tissues supposed to be HGS‐OvCa progenitors. In addition, we recommend miR‐191‐5p as best reference sncRNA in miRNA expression studies with prognostic intent on HGS‐OvCa tissues.
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•Cross-comparison of four different up-to-date analytical methods for the quantification of interface segregation.•An experimental approach was designed to allow the analysis of the ...same location of the specimen with all techniques.•Quantifications are expressed as genuine interface concentrations (atom/nm2).•The case of phosphorus segregation in iron is treated and good agreement (∼30%) between the different quantification methods is shown.
Phosphorus intergranular segregation is known to influence the fracture properties of steels by decreasing grain boundary cohesion and induce intergranular fracture. Different techniques such as Angle-Resolved X-ray Photoelectron Spectroscopy (AR-XPS), Wavelength Dispersive Spectroscopy (WDS), Energy Dispersive X-ray Spectroscopy coupled with Scanning Transmission Electron Microscope (STEM-EDX), and Atom Probe Tomography (APT) can be used to quantify intergranular segregation. Although many studies of this phenomenon were conducted over the last decades, there are rarely direct comparisons between different techniques and there is still a need of reliable and comparable quantification methods for grain boundary segregation. This study cross-compares four available techniques (AR-XPS, WDS, STEM-EDX, and APT) to quantify phosphorus interfacial segregation within the same grain of a sample. This was done by fabricating a Fe-P-Fe sandwich specimen with phosphorus segregated at the interface. Attention was paid to the way of expressing the results of the different techniques so that they can be compared with one another. The quantification results from the different techniques show reasonable agreement.
This paper deals with Ductility Dip Cracking (DDC) during multipass welding of 690 filler metals. In addition to industrial alloys (152 and 52 M), model alloys of controlled purity were also used to ...unambiguously demonstrate the effect of elemental sulphur and carbon. The sensitivity of each alloy to DDC was measured with the recently developed Refusion Cracking Test (RCT). It is confirmed that the cracks observed in this study result from DDC, not from liquation nor solidification cracking. DDC cracks are in most cases observed after several welding passes. The detrimental effect of sulphur and beneficial effect of carbon on the resistance to DDC are clearly evidenced. The good resistance to DDC of the industrial alloys, compared to the model alloys, is related to their niobium content.
Abstract Kidney transplantations combined with other solid organs are progressively increasing in number. There are no guidelines regarding the nephrologic indications for combined transplantations, ...namely liver–kidney (LKT), or heart–kidney (HKT), in preemptive patients with chronic kidney failure who are not on regular dialysis therapy. The objective of this study was to assess the functional contribution of the native kidneys after preemptive kidney transplantation combined with other solid organs. From 2004, 9 patients (aged 50.3 ± 8.5 years) with chronic kidney failure (creatinine 2.5 ± 1.0 mg/dL) caused by polycystic kidney disease ( n = 4), vascular nephropathy ( n = 2), interstitial nephropathy ( n = 1), glomerulonephritis ( n = 1), or end-stage kidney disease ( n = 1), underwent combined transplantations (8 LKT, 1 HKT). A scintigraphic functional study (Tc-99DMSA or Tc-99mMAG3), was performed at 4 ± 3 months after transplantation to evaluate the functional contribution of both the native kidneys and the graft. All patients were given immunosuppressive drugs, including a calcineurin inhibitor (tacrolimus/or cyclosporine). At the time of scintigraphy, renal function in all patients was 1.3 ± 0.3 mg/dL. The functional contribution of the transplanted kidneys was on average 77 ± 18%. Only in 1 patient was the contribution of the graft <50%. At follow-up after 36 months, patient and kidney survivals were 100%. The study confirmed a high risk of loss of native kidney function in the presence of organic nephropathy. In light of our experience, a creatinine clearance <30 mL/min in an appropriate cutoff for a combined transplantation. Close clinical and instrumental assessment pretransplant is essential before proceeding with a combined transplant program to exclude functional forms and to optimize the use of organs.
Abstract Limited information has been published about sporting activities in solid organ transplant recipients. The aim of this study was to assess “in the field” performance capacities of a group of ...transplant recipients involved in an alpine skiing competition. We studied 16 transplant recipients (13 men and 3 women) who had undergone transplantations (11 kidney, 4 liver, and 1 heart) at 89 ± 68 months prior while participating in an alpine skiing race. The patients performed a countermovement jumping test to measure the explosive power of the lower limbs. In all patients blood lactate concentrations (La) were measured at the end of a giant slalom race. The maximum displacement of the center of mass during the jumping test was 22.4 ± 9.3 cm; the time to complete the giant slalom was 75.5 ± 16.5 seconds and La was 3.5 ± 0.8 mmol/L. We observed significant linear relationships between race time and La ( R2 = 0.4733; P < .01) and between race time and performance in the jumping test ( R2 = 0.3655; P < .05). This study indicated that recovery of anaerobic and technical sporting activities is possible in organ transplant recipients. Muscular power and anaerobic performances among a selected group of solid organ transplant recipients were similar to those of the general untrained population.
In spite of the effective implementation of screening programs, uterine cervical carcinoma (UCC) remains one of the major causes of cancer death among women around the world. The aim of this study ...was to investigate the prognostic value of serum human epididymis protein 4 (HE4) in UCC. Pre-treatment serum samples from 109 UCC patients and 99 healthy women were analyzed for HE4 levels by a quantitative chemiluminescent microparticle immunoassay on the automated ARCHITECT instrument. HE4 serum (sHE4) levels were significantly higher in UCC patients, regardless of tumor stage, compared with healthy controls. Elevated sHE4 levels were significantly associated with advanced FIGO stage and absence of disease-free interval after treatment. In univariable analysis, higher sHE4 levels were significantly correlated with shorter overall survival and progression-free survival. In multivariable analysis, sHE4 retained its significance as independent adverse prognostic factor for both survival endpoints. This study indicates that sHE4 is associated with a more aggressive tumor phenotype and a worse patient's prognosis. These results suggest the potential role of sHE4 as a novel prognostic marker and as an indicator of high-risk UCC patients for a tailored surgical and adjuvant therapy.
Chronic allograft nephropathy (CAN) is characterized by progressive renal dysfunction leading in many cases to graft loss. The pathogenesis of CAN involves both immune and nonimmune factors. ...Concerning immune factors, one of the most remarkable predictors of CAN is acute rejection, which is associated with a worse prognosis if there are multiple episodes or when late onset occurs. Delayed graft function is also a major risk factor for CAN because of a correlation between late restoration of renal function after transplantation and long-term decreased graft survival. High creatinine levels at 6 months and 1 year after transplantation, proteinuria, viral infections, and cardiovascular risk factors are additional significant parameters for the development of CAN. Recent findings suggest that a high renal segmental arterial resistance index measured by Doppler ultrasonography in intrarenal vessels is associated with poor allograft function. Moreover, the study of patient genetic profile represents a new approach to identify predictive factors for CAN.
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