ABSTRACT
The in situ combustion (ISC) technique is promisingly applied in heavy oil recovery, whereas the operation inevitably causes high temperature and high pressure for a long duration in the thermal recovery well. As a critical component, oil casing, traditionally made of plain carbon steel in China, generally suffers from poor creep resistance and degraded remnant strength under such a harsh environment, which leads to frequent casing damage and inferior recovery efficiency. In this study, a strategy was adopted to tackle the issue by adding chromium (Cr) element into the plain carbon steel. We designed two types of novel steel with the respective addition of 1 wt.% and 13 wt.% Cr element into plain carbon steel for oil casing. Surprisingly, the trace addition of Cr element with 1 wt.% effectively lowered the creep rate in a creep test at 600 °C and 400 MPa and maintained high remnant tensile strength after creep. More significantly, prior creep history dramatically enhanced remnant strength when Cr element was added up to 13 wt.%. After a long-term creep time of 96 h, the samples were conferred by a stress increment of ~92.5 MPa (~11.0%) relative to the creep-free counterparts, whereas the value was reduced by ~158.4 MPa (~17.8%) for plain carbon steel under the same deformation conditions. Such superior mechanical performances in the Cr-doped steels are mainly ascribed to precipitation retardation of carbides and sluggish precipitate coarsening, which continuously favors a precipitation-strengthening effect in steel. These findings provide a fundamental understanding of precipitation response and creep behaviors and, more importantly, enable the development of high-performance steels used in the field of unconventional petroleum and gas resources.
ABSTRACT
Uric acid, as the terminal product of purine metabolism in the body, is an important marker of many diseases. Uric acid is abundant in saliva, offering the possibility of its non-invasive detection. However, it is sensitive to interference in saliva by a variety of factors. A reliable method of processing saliva is centrifugation (CF), but the cost and size of equipment limit its use in everyday life. In this study, a novel portable salivary-sensing system (PSSS) with integrated suction filtration (SF) and temperature insulation was proposed to obtain more accurate salivary uric acid levels through a simple procedure. The PSSS includes a saliva container, a high-sensitive uric acid sensor (UAS), an accompanying printed circuit board (PCB), and a mobile application. The responses produced by the UAS presents excellent linearity (4.6 µA/mM with R2 = 0.9964), selectivity, reproducibility, and stability for the detection of low levels of uric acid. The difference in detection values between the UAS and the commercial sensor is only ~4%. The primary feature of the saliva container is the processing of saliva by SF instead of CF. Samples from CF and SF showed no significant differences regarding uric acid levels, and both exhibited approximately 50% deviation from the untreated samples, while the difference in uric acid levels between the samples after SF and after applying both treatments was ~10%. Besides, insulation of the saliva container can partially eliminate sources of error induced by the environment during uric acid level testing. The PSSS provides a novel strategy for the immediate detection of specific markers in saliva. We believe that the PSSS has promising potential for future application in the rapid saliva testing.
Subject(s)
Biosensing Techniques , Saliva/chemistry , Uric Acid , Biomarkers , Humans , Reproducibility of ResultsABSTRACT
An ethyl acetate extract from of Nervilia fordii (NFE) with considerable suppression activity on lipid peroxidation (LPO) was first obtained with total phenolic and flavonoid contents and anti-LPO activity (IC50) of 86.67 ± 2.5 mg GAE/g sample, 334.56 ± 4.7 mg RE/g extract and 0.307 mg/mL, respectively. In order to improve its stability and expand its application in antioxidant packaging, the nano-encapsulation of NFE within poly(vinyl alcohol) (PVA) and polyvinyl(pyrrolidone) (PVP) bio-composite film was then successfully developed using electrospinning. SEM analysis revealed that the NFE-loaded fibers exhibited similar morphology to the neat PVA/PVP fibers with a bead-free and smooth morphology. The encapsulation efficiency of NFE was higher than 90% and the encapsulated NFE still retained its antioxidant capacity. Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD) analysis confirmed the successful encapsulation of NFE into fibers and their compatibility, and the thermal stability of which was also improved due to the intermolecular interaction demonstrated by thermo gravimetric analysis (TGA). The ability to preserve the fish oil's oxidation and extend its shelf-life was also demonstrated, suggesting the obtained PVA/PVP/NFE fiber mat has the potential as a promising antioxidant food packaging material.
ABSTRACT
BACKGROUND: This study aimed to analyze the combined diagnostic value of autoantibodies to asialoglycoprotein receptor (anti-ASGPR) and antinuclear antibody (ANA) for autoimmune hepatitis (AIH), and to further explore the role of anti-ASGPR in autoimmune hepatitis. METHODS: According to the clinical diagnosis, the patients were divided into AIH group, viral hepatitis group, alcoholic hepatitis group, fatty liver group, and normal group, then the four groups were compared with the normal group, and the sensitivity and specificity of Anti-ASGPR, ANA and their combination in the diagnosis of AIH were analyzed. Then AIH patients were divided into anti-ASGPR positive group and negative group. The two groups were compared regarding the difference of biochemical and immunological indicators. RESULTS: Only the positive rate of anti-ASGPR and ANA in the AIH group and normal disease group were statistically significant (p < 0.05); in the AIH group, the positive rate of anti-ASGPR and ANA was 63.16% and 71.93%, respectively, the sensitivity and specificity of anti-ASGPR and ANA in parallel were 87.72% and 79.02%, respec-tively, and the Youden index was 0.6674. AIH patients with anti-ASGPR positive had higher levels of immunoglobin G (IgG), alanine aminotransferase (ALT), interleukin-6 (IL-6), interleukin-10 (IL-10), and lower complement C3 than AIH patients with anti-ASGPR negative. CONCLUSIONS: The combined positive of anti-ASGPR and ANA in serum has diagnostic value for AIH, and anti-ASGPR may be related to the disease activity, inflammatory reaction, and pathogenesis of AIH.