•B2- Cu-enriched precipitates exist in the studied model alloys.•The maximum contribution to precipitation hardening is attributed to Cu-enriched precipitates.•Ni addition led to relatively higher ...precipitation nucleation and growth of Cu-enriched precipitates.•Small-angle scattering could provide better details when analyzing nano-sized precipitates.
To better understand the mechanisms of thermally aged and embrittled reactor pressure vessel steels, the hardening behavior and microstructure evolution of different Fe-Cu and Fe-Cu-Ni model alloys were investigated using transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) analysis methods. The effects of different aging conditions and alloy composition on the formation and growth of Cu-enriched precipitates were discussed. The results showed that the hardness of the Fe-Cu model alloys with low copper content continuously increased with aging, increasing to peak hardness and then decreasing for the Fe-Cu model alloys with high copper content. The aging time to reach peak hardness was greatly reduced due to the addition of Ni in the Fe-Cu model alloys. The TEM results showed that with increased aging temperature and copper content, the Cu-enriched precipitates with a B2 structure precipitated in the ferritic matrix following a direct relationship. Therefore, Ni addition led to relatively higher precipitation nucleation and growth, and the size distribution of the Cu-enriched precipitates derived from the SANS was in overall good agreement with the TEM observations for 6–25 nm regions. Therefore, small-angle scattering could provide better details when analyzing smaller, nano-sized precipitates.
Microstructure evolution and mechanical properties in an Fe-17Cr-4Ni-4Cu alloy aged at 475 °C after different aging times were studied. Conventional transmission electron microscopy (TEM) and ...high-resolution electron microscopy (HREM) studies revealed the formation of 9R-structure Cu-rich precipitates and Cr-rich α’ phase by spinodal decomposition in the samples aged at 475 °C after 100–1000 h. The fine Cu-rich precipitates and Cr-rich α’ phase by spinodal decomposition lead to a significant increase in the hardness, together in the early stages (100 h). Continued aging to 500 h leads to increased precipitation of the Cr-rich α’, which provides significant strengthening, reaching maximum hardening, despite the continued loss of hardening by weakening by the Ostwald ripening of the Cu-rich precipitates. Extending the aging time to 1000 h leads to substantial reversed austenite transformation and a large number of ripening -copper precipitates that causes softening. The results of the impact tests showed that the major fracture mode was cleavage and/or quasi-cleavage.
The present research investigated whether critical thinking predicts academic performance above and beyond general cognitive ability. Both critical thinking (CT) skills and dispositions were ...investigated in order to obtain a complete picture of CT and its relations to academic performance and general cognitive ability including fluid intelligence, working memory and processing speed. Measures of these variables were administrated to both university young adults (N = 232, study 1, a self-report scale was used for assessing academic performance) and primary school children (N = 158, study 2). Both studies showed that CT indicated by skills and dispositions made unique contributions to academic performance even when general cognitive ability was controlled for. Further, it was mainly CT dispositions that uniquely contributed to academic performance while the contribution of CT skills to academic performance largely overlapped with general cognitive ability. Our findings provide a first step toward understanding CT as a distinct construct from general cognitive ability in relation to learning and academic performance.
•Critical thinking (CT) predicts academic performance (AP) beyond general abilities.•It was mainly CT dispositions that uniquely added to the prediction of AP.•CT skills largely overlapped with general cognitive abilities in predicting AP.•The findings above were stable across children and adults samples.•CT overlapped more with general abilities in predicting AP in the children sample.
An adaptive learning method for tool wear monitoring, taking the time of one machining process step as a monitoring period, is proposed, which aims to provide new ideas for tool life research and ...improve the reliability of machine tool operation. First, the motor current signal is collected as the original signal, and the RMS (root mean square) value of the current signal is extracted as the characteristic quantity. Statistical analysis of characteristic quantity RMS using SPSS (Statistical Product and Service Solutions) method shows that the RMS value of current signal obeys normal distribution approximately in the monitoring period with process step as the unit. Then, a monitoring method based on ± 3σ principle of normal distribution is proposed. Although RMS does not follow normal distribution completely, it is still possible to estimate the dispersion range of RMS by introducing distribution coefficient
K
through ± 3σ principle of statistical mathematics. Finally, a self-learning algorithm for the boundary mathematical model of tool wear monitoring is presented. According to the analysis of tool wear, the tool failure time could be calculated, and the tool life can be predicted. The experimental results show that the monitoring model can be formed quickly during semi-finishing and finishing machining and can get the satisfactory monitoring results.
Abstract
Background
Overweight and obesity have become major public health concerns worldwide. Persistent stress can activate the human hypothalamic‒pituitary‒adrenal axis (HPA) and increase the ...intake of “self-rewarding food”, thereby raising the incidence of obesity. Health care workers (HCWs) experience higher workloads and mental stress than workers in many other industries, which may put them at increased risk for overweight/obesity. However, few studies have been carried out on overweight and obesity among HCWs in China, and the overall scenario and behind-the-scenes factors of their overweight and obesity are unknown. The aim of this study is to understand the epidemic of overweight and obesity and risk factors among Chinese HCWs.
Methods
Based on a cross-sectional web survey design, 23,234 HCWs from 100 health institutions in 5 provinces/autonomous regions/municipalities across China were sampled to answer a self-administered questionnaire that was purposely developed using a multi-staged clustered random-sampling method. Chi-square test and ANOVA were performed to compare variables between two or more groups. Univariate analyses were conducted to identify the influence of self-reported persistent stress and/or recurrent anxiety/depressed mood on lifestyle behaviors. A multivariate binary logistic regression model was used to analyse the risk factors of overweight/obesity.
Results
Among the respondents, 34.26% were overweight, and 11.22% were obese. Most of the respondents had regular exercise habits (68.17%), had habitually stayed-up late (65.06%) and had been affected by persistent stress and/or recurrent anxiety/depressed mood (62.04%). A higher proportion of those with persistent stress and/or recurrent anxiety/depressed mood than those without habitually staying-up late (76.18%); consumed take-out food (54.92%), fried food (49.93%), snacks or desserts (50.51%); drank sugary drinks (46.57%); smoked (14.27%); and drank alcohol (23.34%). Gender (Female) (OR: 0.314, 95%CI: 0.292–0.336), age (OR: 1.742–2.334, 95%CI: 1.544–2.858), education (OR: 0.620–0.728, 95%CI: 0.445–0.973), living and working area (OR: 1.271, 95%CI: 1.192–1.355), breakfast (OR: 0.898, 95%CI: 0.839–0.960), fried food (OR: 1.133, 95%CI: 1.048–1.224), and alcohol consumption (OR: 1.111, 95%CI: 1.017–1.214) were factors for overweight/obesity. All of the aforementioned results were significant (
P
< 0.05).
Conclusions
The overweight/obesity rate of Chinese HCWs is rather high, which might be directly associated with lifestyle behaviors. However, these behaviors fundamentally originated from persistent stress and/or recurrent anxiety/depression, mediated by lifestyle behaviors. Substantial measures should be taken for stress reduction and mental health promotion for overweight/obesity prevention and control among HCWs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Purpose
It is challenging to differentiate unilateral aldosterone-producing adenoma (APA) from bilateral idiopathic adrenal hyperplasia (IAH) and nonfunctional adrenal adenoma (NFA) in primary ...aldosteronism (PA). In a first primarily ex vivo study detection, CXC chemokine receptor type 4 (CXCR4) expression has been shown to be a valuable tool for the detection of APA. In this study, we aimed to clinically evaluate CXCR4 imaging with
68
Ga-pentixafor PET/CT for detecting APA.
Methods
We prospectively recruited 36 patients with clinical suspicion of PA. All patients underwent
68
Ga-pentixafor PET/CT. Positive lesions were defined based on higher tracer uptake in adrenal nodular(s) shown on CT than the normal adrenal. These lesions were referred for adrenalectomy subsequently. All patients received clinical follow-up. Semi-quantitative analysis using maximum standardized uptake value (SUV
max
), lesion-to-liver ratio (LLR), and lesion-to-contralateral ratio (LCR) has also been performed. PET/CT results were correlated with clinical presentation and follow-up.
Results
Thirty-nine adrenal lesions in 36 patients were found; 25 APA, 4 IAH, and 10 NFA according to histopathology and clinical assessment. Sensitivity, specificity, and accuracy of
68
Ga-pentixafor PET/CT in distinguishing APA by visualization were 100%, 78.6%, and 92.3% respectively. The SUV
max
of APA (21.34 ± 9.41,
n
= 25) was significantly higher than that of non-APA lesions (6.29 ± 2.10,
n
= 14,
P
< 0.0001). An optimal threshold of SUV
max
= 11.18 was determined for predicting APA with a sensitivity of 88.0%, specificity of 100%, and an accuracy of 92.3%. A cutoff value for LCR of 2.12 yielded a sensitivity of 100% and a specificity of 92.9%, whereas a cutoff value for LLR of 2.36 reached at both 100% of sensitivity and specificity. All patients with (removed) positive lesions benefited from surgery.
Conclusion
68
Ga-Pentixafor PET/CT may be used to non-invasively detect APA in PA patients.
FL118, a novel camptothecin analogue, has been extensively studied for its superior antitumor potency. The aim of this research study is to explore its potential mechanism of action in anti- ...colorectal cancer (CRC).
The effect of FL118 on CRC cell proliferation was assessed using CCK-8 assay, while apoptosis was detected using Hoechst staining and Flow cytometry assays. The expression levels of CIP2A were analyzed using qRT-PCR. The expression of CIP2A, PP2A-C, Bax, cleaved caspase-3 and PARP were analyzed using western blotting analysis. The expressions of related proteins in CRC tissues were detected using immunohistochemical staining. TUNEL assay was used to detect apoptosis of tissue. Toxicity of FL118 in primary organs were examined using H&E staining.
The results show that FL118 can inhibit the proliferation and clonogenic potential of CRC cells and increase the expression of pro-apoptosis proteins, Bax, cleaved caspase-3 and PARP. Microarray analyses found that FL118 treatment significantly decreases cancerous inhibition of protein phosphatase 2A (CIP2A). Further validation found that CIP2A is aberrantly upregulated in CRC tissues, and is positively correlated with the progression of CRC. In vitro findings confirm that FL118 mediates the downregulation of CIP2A, at both protein and mRNA levels. Co-treatment with Okadaic acid (OA) (a PP2A inhibitor) partially abolishes the anti-proliferative and pro-apoptotic effect of FL118. Consistently, in vivo experiment demonstrates that FL118 can effectively suppress tumorigenesis without any obvious toxic effects.
Collectively, these findings exhibit the anti-neoplastic effects of FL118 against CRC through the down regulation of CIP2A, which subsequently enhances the activity of PP2A.
It is very difficult to avoid the problem of tool wear or breakage during the machining of CNC machine tools. Failure to detect and stop the machine in time is likely to cause damage to the machine ...or workpiece. This requires the on-line monitoring of the tool state during machining. In this paper, a load-based tool wear monitoring method is proposed. The self-learning method is adopted to obtain the load range of a specific machining process, so that on-line monitoring of the subsequent same machining process can be carried out. Self-learning is mainly used to process the load signal by using the statistical algorithm (6σ algorithm), so as to obtain the upper and lower boundary of the monitoring range. The load signals in the subsequent machining process are compared with the upper and lower boundaries determined by the self-learning algorithm to determine whether the tool is worn or not. Finally, the feasibility of this method was verified by experiments.
