Migration Behavior of Inclusions at the Solidification Front in Oxide Metallurgy.

Distribution of inclusions plays an essential role in inducing intracrystalline ferrite, and the migration behavior of inclusions during solidification has a significant influence on their distribution. The solidification process of DH36 (ASTMA36) steel and the migration behavior of inclusions at the solidification front were observed in situ using high-temperature laser confocal microscopy. The annexation, rejection, and drift behavior of inclusions in the solid-liquid two-phase region were analyzed, providing a theoretical basis for regulating the distribution of inclusions. Analysis of inclusion trajectories showed that the velocity of inclusions decreases significantly as they near the solidification front. Further study of the force on inclusions at the solidification frontier shows three situations: attraction, repulsion, and no influence. Additionally, a pulsed magnetic field was applied during the solidification process. The original dendritic growth mode changed to that of equiaxed crystals. The compelling attraction distance for inclusion particles with a diameter of 6 µm at the solidification interface front increased from 46 µm to 89 µm, i.e., the effective length for the solidification front engulfing inclusions can be increased by controlling the flow of molten steel.

Effect of Molybdenum on the Impact Toughness of Heat-Affected Zone in High-Strength Low-Alloy Steel.

The microstructure, precipitates, and austenite grain in high-strength low-alloy steel were characterized by optical microscope, transmission electron microscope, and laser scanning confocal microscopy to investigate the effect of Mo on the toughness of steel. The microstructure was refined and the toughness was enhanced after the addition of 0.07% Mo in steel. The addition of Mo can suppress the Widmanstätten ferrite (WF) formation and promote the transformation of acicular ferrite (AF), leading to the fine transformed products in the heat-affected zone (HAZ). The chemical composition of precipitates changed from Nb(C, N) to (Nb, Mo)(C, N) because of the addition of Mo. The calculated lattice misfit between Nb(C, N) and ferrite was approximately 11.39%, while it was reduced to 5.40% for (Nb, Mo)(C, N), which significantly affected the size and number density of precipitates. A detailed analysis of the precipitates focusing on the chemical composition, size, and number density has been undertaken to understand the contribution of Mo on the improvement of steel toughness.

Circular RNA circZFR promotes tumorigenic capacity of lung cancer via CCND1.

BACKGROUND: To explore the role of circular RNA (circRNA) circZFR in tumorigenic capacity of lung cancer (LC). METHODS: Thirty primary LC tissues were used to detect circRNAs expression. CircZFR was silenced in two LC cell lines using lentivirus-mediated short hairpins RNAs. Quantitative real time PCR (qRT-PCR), northern blot and in situ hybridization (ISH) assay were used to measure the expression of circRNA. RESULTS: CircRNA circZFR was highly expressed in LC tumors. CircZFR deficiency significantly abrogated clone formation. CircZFR depletion substantially decreased tumor growth compared to WT control cells. CircZFR overexpression was dramatically increased cell growth in LC cell lines. Consequently, circZFR overexpression substantially promoted tumor propagation. Consistently, circZFR deficiency significantly reduced the expression of CCND1 and major cell cycle genes in LC cell lines. In contrast, circZFR depletion did not alter the expression of ZFR. Consequently, circZFR deficiency dramatically decreased H3K4me3 levels on the CCND1 promoter at -1,100 to -900 bp segment of CCND1 promoter. CONCLUSIONS: CircZFR was related with LC growth in vitro and in vivo and tumorigenic capacity of LC. The possible mechanism was to regulating expression of CCND1, indicating the circZFR/CCND1 signaling might be a promising therapeutic target for LC treatment.

Erratum to rhinovirus is associated with severe adult community-acquired pneumonia in China.

[This corrects the article DOI: 10.21037/jtd.2017.10.107.].

Rhinovirus is associated with severe adult community-acquired pneumonia in China.

BACKGROUND: Human rhinovirus (HRV) is one of the most common viral etiologies detected in community-acquired pneumonia (CAP) adult cases. However, few is known about the characteristics of HRV-associated CAP. To describe the clinical features of HRV-associated CAP in immunocompetent adults admitted to multiple medical centers in mainland China over a 2-year period. METHODS: A total of 383 patients admitted to hospitals for CAP were enrolled from 46 medical centers in mainland China between January 2013 and December 2014. Multiplex real-time polymerase chain reaction (RT-PCR) assays for viral detection and DNA-based quantitative loop-mediated isothermal amplification (qLAMP) assays for bacterial detection were implemented to all lower respiratory tract specimens obtained from the patients. Twenty-eight cases (28/383, 7.3%) revealed HRV-positive PCR results. Patients with bronchoalveolar lavage (BAL) HRV-positive PCR results (n=20) were further enrolled and divided into two groups depending on the status of bacterial co-infection (viral group, n=12; viral-Bacterial group, n=8). Demographic, clinical and microbiological data were reviewed and compared in detail. RESULTS: Cases with HRV-infection were remarkably correlated with respiratory failure (14/20) and most of them (13/14) received mechanical ventilation. Fever (17/20), productive cough (15/20) and dyspnea (6/20) were common symptoms while flu-like symptoms were rarely observed in the cohort. Streptococcus pneumoniae (3/8), Klebsiella pneumoniae (3/8) and Mycoplasma pneumoniae (2/8) were most frequently identified bacterium in the viral-bacterial group. Compared with the viral group, higher incidence of septic shock (3/8 vs. 1/12, P=0.255), longer ICU length of stay (LOS) (10.0 vs. 6.5 days, P=0.686), longer hospital LOS (18.5 vs. 13.0 days, P=0.208) and higher 28-day mortality (2/8 vs. 2/12, P=1) were observed in the Viral-Bacterial group, although without statistically significant difference. CONCLUSIONS: HRV is a common etiology in CAP among China adults, especially in severe CAP. Clinicians should be vigilant considering of the poor outcome. Highly qualified multiplex PCR techniques with invasive sampling are needed to increase the detection rate.

Genotyping of human rhinovirus in adult patients with acute respiratory infections identified predominant infections of genotype A21.

Human rhinovirus (HRV) is an important causative agent of acute respiratory tract infections (ARTIs). The roles of specific HRV genotypes in patients suffering from ARTIs have not been well established. We recruited 147 adult inpatients with community-acquired pneumonia (CAP) and 291 adult outpatients with upper ARTIs (URTIs). Respiratory pathogens were screened via PCR assays. HRV was detected in 42 patients, with 35 species A, five B and two C. Seventeen genotypes were identified, and HRV-A21 ranked the highest (9/42, 21.4%). The HRV-A21-positive infections were detected in four patients with CAP and in five with URTIs, all without co-infections. The HRV-A21 genome sequenced in this study contained 12 novel coding polymorphisms in viral protein (VP) 1, VP2 EF loop, VP3 knob and 3D regions. The infections of HRV-A21 virus obtained in this study could not be neutralized by antiserum of HRV-A21 prototype strain (VR-1131), indicating remarkable antigenic variation. Metagenomic analysis showed the HRV-A21 reads were dominant in bronchoalveolar lavage fluid of the three HRV-A21-positive patients with severe CAP, in which two dead. Our results highlight an unexpected infection of genotype HRV-A21 in the clinic, indicating the necessity of precise genotyping and surveillance of HRVs to improve the clinical management of ARTIs.