Numerical computation and experimental assessment of a pressure-retaining gas-tight sediment sampler.

The pressure of the recovered sample is intricately connected to seawater temperature, the recovery velocity, and the pressure of the pre-charged gas. To better understand the sample pressure dynamics during the sampling recovery process, we focus on a gas-tight sediment sampler, delving into its pressure-compensation and pressure-retaining mechanisms. A comprehensive thermal and thermodynamic analysis is conducted throughout the entire pressure-retaining sampling process, examining the temporal variations in the temperatures of seawater and nitrogen within the sampler at various descending velocities. The heat transfer and thermodynamics are examined throughout the entire pressure-retaining sampling process to determine how changes in the temperatures of seawater and nitrogen, as well as the descent velocity, affect the pressure-retaining performance. The influence of pre-charging pressure and recovery velocities on the pressure-retaining performance of the sampler is examined. Then the proposed numerical model was well verified by the ultra-high-pressure vessel experiments of the sampler under 115 MPa. Finally, the sea trial results further verified the accuracy of the numerical model.

Sealing performance of sealing structure in a sediment sampler under ultra-high pressure.

As a key component of a sediment sampler designed for ultra-high pressures, the sealing structure determines whether pressure retention can be reliably achieved. This study constructed a finite element model to study sealing performance and reveal the sealing mechanism. The effects of the hardness and compression rate of O-ring as well as seawater pressure on the sealing performance were studied. The study showed that a self-tightening seal can be formed when the coefficient of friction on the sealing surface is less than or equal to 0.25. In addition, the maximum contact stress of the O-ring increased nearly linearly with increasing pressure, and it was larger than the corresponding pressure. However, with increasing pressure, the maximum Von-Mises stress initially increased rapidly, then tended to stabilize, and then continued to increase. Although increasing the hardness reduced the principal strain, the stress increased correspondingly. Within the compression rate range from 10 to 25%, the hardness of the O-ring had a greater impact on the contact pressure than the compression rate. In order to further verify that the finite element analysis was accurate, the sealing performance was tested, and the results showed that the seal was reliable and capable of sealing a deep-sea sampler.

Underwater image restoration based on adaptive parameter optimization of the physical model.

Underwater images have the advantage of carrying high information density and are widely used for marine information acquisition. Due to the complex underwater environment, the captured images are often unsatisfactory and often suffer from color distortion, low contrast, and blurred details. Physical model-based methods are often used in relevant studies to obtain clear underwater images; however, water selectively absorbs light, making the use of a priori knowledge-based methods no longer applicable and thus rendering the restoration of underwater images ineffective. Therefore, this paper proposes an underwater image restoration method based on adaptive parameter optimization of the physical model. Firstly, an adaptive color constancy algorithm is designed to estimate the background light value of underwater image, which effectively guarantees the color and brightness of underwater image. Secondly, aiming at the problem of halo and edge blur in underwater images, a smoothness and uniformity transmittance estimation algorithm is proposed to make the estimated transmittance smooth and uniform, and eliminate the halo and blur of the image. Then, in order to further smooth the edge and texture details of the underwater image, a transmittance optimization algorithm for smoothing edge and texture details is proposed to make the obtained scene transmittance more natural. Finally, combined with the underwater image imaging model and histogram equalization algorithm, the image blurring is eliminated and more image details are retained. The qualitative and quantitative evaluation on the underwater image dataset (UIEBD) shows that the proposed method has obvious advantages in color restoration, contrast and comprehensive effect, and has achieved remarkable results in application testing. It shows that the proposed method can effectively restore underwater degraded images and provide a theoretical basis for the construction of underwater imaging models.

Small obstacle size prediction based on a GA-BP neural network.

Accurate and effective acquisition of obstacle size parameters is the basis for environment perception, path planning, and autonomous navigation of mobile robots, and is the key to improve the walking performance of mobile robots. In this paper, a generic algorithm-back propagation (GA-BP) neural network-based method for small obstacle size prediction is proposed for mobile robots to perceive the environment quantitatively. A machine vision-based small obstacle size measurement experiment was designed, and 228 sets of sample data were obtained. A genetic algorithm optimized back propagation neural network was used to build a small obstacle size prediction model with obstacle pixel width, pixel height, pixel area, and obstacle-to-camera distance as input parameters and actual obstacle width, actual height, and actual area as output parameters. The results show that the correlation coefficient (R2) between the predicted and expected values of the test data is higher than 0.999, the root mean square error is lower than 5.573, and the mean absolute percentage error is lower than 2.84%. The good agreement between its predicted and expected values indicates that the model can accurately predict the size of small obstacles. The GA-BP neural network-based small obstacle size prediction method proposed in this paper is simple to execute, has good real-time performance, and provides a new, to the best of our knowledge, way of thinking for mobile robots to acquire environmental data.

The Later Status and Impact Factors of Physical Activity among Patients after Percutaneous Coronary Intervention in China.

Objectives: In this study, we investigated the physical activity status and impact factors in patients after percutaneous coronary intervention in China. Methods: This cross-sectional survey was conducted from January to October 2019. A total of 260 participants were recruited in the cardiovascular department who had successfully undergone percutaneous coronary intervention after one year for physical re-examination at 2 hospitals in Henan Province. They were investigated using 5 questionnaires - the International Physical Activity Questionnaire-Long Form, the Exercise Self-efficacy Questionnaire, the Multi-dimensional Fatigue Scale, the Social Support Rating Scale, and the Hospital Anxiety and Depression scale. Results: After percutaneous coronary intervention, most patients were at low and moderate intensity physical activity and 60.8% of patients did not meet the recommended amount of guidelines. Through the analysis of the influencing factors of physical activity in patients with coronary heart disease stent implantation, the status of physical activity was affected by the NYHA classification, LVEF, exercise self-efficacy, fatigue, and social support. Conclusions: The level of physical activity of patients after percutaneous coronary intervention needs to be improved further. In clinical practice, nursing practitioners should strengthen the health education of patients' exercise rehabilitation to improve the level of physical activity and reduce the occurrence of cardiovascular events.

MicroRNA-652 promotes cell proliferation and osteosarcoma invasion by directly targeting KLF9.

Previous studies have demonstrated that various microRNAs (miRNAs or miRs) are abnormally expressed in osteosarcoma (OS) and serve roles in its malignant development. An in-depth understanding of the specific roles of dysregulated miRNAs in OS may be important for cancer research and the identification of novel therapeutic targets. In the current study, reverse transcription-quantitative PCR was performed to determine miR-652 expression in OS tissues and cell lines. Cell Counting Kit-8 and Transwell invasion assays were used for assessing the effect of miR-652 on the proliferation and invasion of OS cells. Herein, miR-652 expression was assessed in OS and the effects and molecular mechanisms of miR-652 in OS cells were examined. The results revealed that miR-652 expression was significantly upregulated in OS tissues and cell lines compared with adjacent normal tissues and a normal human osteoblast cell line. Furthermore, miR-652 downregulation inhibited the proliferation and invasion of OS cells. miR-652 was also demonstrated to directly interact with the 3'-untranslated region of kruppel-like factor 9 (KLF9) and miR-652 negatively regulated KLF9 expression in OS cells. miR-652 and KLF9 mRNA levels were also revealed to be inversely correlated in OS tissues. Treatment with KLF9 small interfering RNA abolished the suppression of OS proliferation and invasion induced by miR-652 downregulation. miR-652 may serve an oncogenic role in OS cells by targeting KLF9 directly. The results also indicated that miR-652 may be an effective novel therapeutic target for the treatment of patients with OS.

Circular RNA KIF4A promotes cell migration, invasion and inhibits apoptosis through miR-152/ZEB1 axis in breast cancer.

BACKGROUND: Circular RNAs (circRNAs) have been demonstrated to exert crucial mediators in tumor initiation and development. Nevertheless, the roles of circKIF4A in breast cancer (BC) are still not very clear. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine the expression of circKIF4A, miR-152, zinc finger E-box binding homeobox 1 (ZEB1) mRNA and caspase-3. Western blot assay was utilized to examine the protein level of ZEB1. Transwell assay and flow-cytometric analysis were adopted for the evaluation of cell migration, invasion and apoptosis, respectively. The associations among circKIF4A, miR-152 and ZEB1 were predicted by online websites and verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. RESULTS: CircKIF4A and ZEB1 were conspicuously upregulated and miR-152 was markedly reduced in BC tissues and cells. Deficiency of circKIF4A repressed migration, invasion and induced apoptosis of BC cells. Moreover, circKIF4A was confirmed to be a sponge of miR-152 and miR-152 could bind to ZEB1. MiR-152 inhibition or ZEB1 overexpression abolished the impacts of circKIF4A knockdown on cell migration, invasion and apoptosis in BC. CONCLUSION: Silencing of circKIF4A hampered cell metastasis and promoted apoptosis by regulating ZEB1 via sponging miR-152 in BC.

miR-496 remedies hypoxia reoxygenation-induced H9c2 cardiomyocyte apoptosis via Hook3-targeted PI3k/Akt/mTOR signaling pathway activation.

The hypoxia-reoxygenation (H/R) model helps analyze myocardial infarction triggered by acute myocardial ischemia, which induces cardiomyocyte proliferation and apoptosis. The Gene Expression Omnibus database was used to obtain the GSE74205 and GSE3866 microarray data, including microRNA (miRNA) and messenger RNA profiles, to catalog potential key miRNAs and genes. The role of rno-mir-496 expression in cardiomyocyte proliferation within 10 days of birth was established. The microRNA Target Prediction Database (miRDB) database-via Gene Ontology annotation-predicted hook microtubule tethering protein 3 (Hook3), a key target gene of rno-mir-496, was closely related to cell proliferation. Upregulation of miR-496 related to a significant reduction in apoptosis of H9c2 and human cardiomyocytes treatment with H/R. Moreover, transfection of H9c2 cells with miR-496 mimics, which were pretreated with H/R for 12 hours, increased Ki67 levels, proliferating cell nuclear antigen and Bcl-2 proteins; and decreased cleaved caspase-3 and Bax protein levels, as determined by reverse transcription-polymerase chain reaction and Western blot assays. A dual-luciferase reporter system confirmed that miR-496 targets the Hook3 suppressor. Hook3 overexpression stimulated apoptosis in H/R-treated cells, thus reducing cell proliferation. Upregulated miR-496 activated phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling, while Hook3 exhibited the inverse trend in H/R-treated H9c2 cells. In summary, with Hook3 functionality's aid, miR-496 upregulation defends cells from H/R-induced apoptosis and stimulates cell proliferation. miR-496 targets Hook3 to trigger the PI3K/Akt/mTOR signaling pathway for antiapoptotic and proliferative effects.

Association of liver enzymes levels with fasting plasma glucose levels in Southern China: a cross-sectional study.

OBJECTIVE: According to several studies, liver enzymes levels are associated with fasting plasma glucose (FPG) levels. However, the association stratified by body mass index (BMI) remains to be elucidated, especially in Southern China. Therefore, the aim of this study was to investigate the correlation between liver enzymes levels and FPG levels stratified by BMI in Southern China. DESIGN: Cross-sectional study. PARTICIPANTS AND SETTING: 3056 individuals participated in real-time interviews and blood tests in Southern China. Participants were divided into three groups (underweight, normal weight and overweight or obesity) based on BMI cut-offs. MAIN OUTCOME MEASURED: Partial correlation analysis was performed to investigate the relationship between FPG levels and liver tests. Multivariate logistic regression analyses were applied to calculate the adjusted ORs for FPG levels based on liver enzymes levels. RESULTS: There was no association between liver enzymes and FPG either in the underweight group or in the normal weight group; however, a significant correlation was observed in the overweight or obesity group (alanine transaminase (ALT), p<0.01; aspartate aminotransferase (AST), p<0.05). After adjusting for confounding factors, the highest tertiles of ALT still remained significantly positively related to FPG levels in the overweight or obesity group, with an OR of 2.205 (95% CI 1.442 to 3.371) for the 5.56≤FPG<7.00 mmol/L vs the FPG<5.56 mmol/L group and with an OR of 2.297 (95% CI 1.017 to 5.187) for the FPG≥7.00 mmol/L vs the FPG<5.56 mmol/L group, but this correlation was not found for AST. CONCLUSIONS: The association of liver enzymes levels with FPG levels differed based on different BMI cut-offs. ALT levels were significantly positively associated with FPG levels in the overweight or obesity group, but not in the other two groups; AST levels were not associated with FPG levels in any group.

The Biochemical Markers Associated with the Occurrence of Coronary Spasm.

Coronary artery spasm (CAS) is one of the mechanisms of angina pectoris. Unlike the diagnosis of acute myocardial infarction which is based on the elevation of cardiac markers, the diagnosis of CAS is difficult and sometimes requires sophisticated and risky provocative test which is not widely accepted in China. There is no well-established biomarker for the diagnosis or prediction of CAS. However, there are some biomarkers proven to be associated with the occurrence of CAS. For example, inflammatory factors including C-reactive protein and cytokines, lipoprotein (a), and cystatin-C might be precipitating factor for CAS. Rho-kinase as a mediator involved in multiple mechanisms of CAS, serotonin, and endothelin-1 as powerful vasoconstrictors leading to vasospasm were all observed being elevated in patients with CAS. Thioredoxin and nitrotyrosine reflected the oxidative status and could be observed to be elevated after the occurrence of CAS. In some cases doubted to be CAS without the evidence of provocative test, the blood test for the biomarkers mentioned above could be useful for the diagnosis of CAS.

Aberrant expression of TNRC6a and miR-21 during myocardial infarction.

In the present study, aberrant expression of trinucleotide repeat-containing gene 6a (TNRC6a) and miR-21 was noted and documented in rat myocardial infarction. Briefly, Sprague-Dawley rat model was used for the development of myocardial infarction. Experiments such as histological analysis were carried out to confirm the histopathology of the myocardial infarction. The expression profile of TNRC6a and miR-21 was identified by using quantitative real-time PCR. In addition, immunoblotting was performed to validate the expression profile of TNRC6a and phosphatase and tensin homolog (PTEN). The histological analysis confirmed the progress of myocardial infarction in rat model. As the disease progresses, the protein TNRC6a expresses abnormally which in turn up-regulates the miR-21 after 3rd and 5th week of infarction. Interestingly, miR-21 binds with its specific target genes PTEN and thereby degrades the target mRNA; as a result, its expression was down-regulated progressively and paved the development of myocardial infarction. The present study concludes that the aberrant expression of TNRC6a and miR-21 was documented during myocardial infarction. These findings play an important role in the diagnosis as well as pave a way for the development of drug targets for treating myocardial infarction.

Early neurological deterioration during the acute phase as a predictor of long-term outcome after first-ever ischemic stroke.

Early neurological deterioration (END) is associated with increased risk of functional disability and mortality. However, data are limited regarding the long-term risk of poor functional outcomes. Thus we explored the association between END and long-term outcomes in patients with acute ischemic stroke.A total of 1064 patients were enrolled with acute ischemic stroke who were consecutively admitted to the 3 stroke units of Huai-He Hospital, Kaifeng, China. END was defined as an increment change of at least one point in motor power or total National Institute of Health Stroke Scale (NIHSS) score deterioration ≥2 points within the first week after admission. We retrospectively assessed the risk factors of END and prospectively explored the relationship between END and the long-term outcomes by multivariable regression models after adjusting the potential confounding factors. Outcomes were evaluated at 18 months based on modified Rankin scale (MRS) scores.Approximately 32% of first-ever ischemic stroke patients experienced END during the acute phase. END was associated with diabetes (odds ratio [OR], 2.218; 95% confidence interval [CI] 1.619-3.037), NIHSS score at admission (OR, 1.052; 95% CI 1.023-1.082), C-reactive protein (CRP) levels (OR, 1.224; 95% CI 1.066-1.406]), and homocysteine (HCY) levels (OR, 1.203; 95% CI 1.061-1.365) after adjusting related factors, such as hypertension, diabetes, NIHSS at admission, and some blood laboratory values, including direct bilirubin, total cholesterol, low-density lipoprotein, glucose, CRP, HCY, and D-dimer levels. During the follow-up period, 52 (4.9%) patients died, 160 (15.0%) recrudesced, and 317 (29.8%) suffered poor outcomes. Multivariate logistic regression analyses revealed that poor outcome was associated with END (OR, 3.366; 95% CI 2.495-4.542), age (OR, 1.028; 95% CI 1.015-1.041), body mass index (OR, 1.096; 95% CI 1.051-1.144), coronary heart disease (OR, 1.637; 95% CI 1.108-2.416), and CRP (OR, 2.474; 95% CI 1.840-3.326).The risk factors of END are multifaceted. Diabetes, NIHSS score at admission, CRP, and HCY are independent predictors of END. In addition, the results of this study indicate that END is an important predictor of poor functional outcome.

Serum albumin level is associated with the recurrence of acute ischemic stroke.

BACKGROUND: Previous studies have confirmed that low serum albumin levels in acute ischemic stroke patients increased the risk for poor outcome and death, demonstrating the neuroprotective role of albumin. However, there are few studies investigating the relationship between albumin levels and recurrence of stroke. The aim of this study was to evaluate the effect of serum albumin level on the risk of recurrence in patients with acute ischemic stroke. METHODS: Seven hundred fifty-three consecutive patients with acute first-ever ischemic stroke were recruited in this study. Recurrent outcome was measured 1 year after stroke through home interviews (n = 692). RESULTS: Patients with recurrence had significantly lower serum albumin level than those without recurrence (37.07 ± 4.21 vs 38.91 ± 3.25). The multiple logistic regression adjustment for confounding factors showed that the association remained significant for patients in the second albumin quartile, the third quartile, and the fourth quartile compared with patients in the first quartile (adjusted odds ratio [aOR] = 0.543, 95% confidence interval [CI]: 0.307-0.959, P= .036; aOR = 0.449, 95% CI: 0.249-0.812, P= .008; and aOR = 0.290, 95% CI: 0.148-0.570, P < .001). CONCLUSION: Lower serum albumin level increases the risk of recurrence in patients with acute ischemic stroke, suggesting that serum albumin level might be used as an indicator for stroke recurrence.

[Determination of ascorbic acid by suppressed chemiluminescence].

This paper describes a method for determining ascorbic acid by the suppression of DTMC-H2O2 chemiluminescence. Various factors affecting the chemiluminescence determination of ascorbic acid were examined. Under the optimal conditions (1.2 x 10(-4) mol.L-1 of DTMC, 5.0 x 10(-5) mol.L-1 of H2O2, and pH 11.4 Na2HPO4-NaOH), the quenching of the chemiluminescent intensity was proportional to the concentration of ascorbic acid in the range of 1.0 x 10(-7)-8.0 x 10(-6) mol.L-1, and the detection limit was 8.0 x 10(-8) mol.L-1 (S/N = 3). The RSD was 4.6% for 1.0 x 10(-6) mol.L-1 of ascorbic acid (n = 10). The selectivity of this method was high and no making agent required. The proposed method has been applied to the determination of ascorbic acid in real samples. The obtained results were in agreement with those by CuSO4-KI titration.