311 research outputs found

    The Cultivation of College Students’ Critical Thinking Ability Based on Task-based Cooperative Writing

    Get PDF
    This study attempts to explore the effectiveness of task-based cooperative writing instruction on critical thinking and English writing development. To address the issues, an experiment is carried out between two university classes, who received task-based cooperative writing and traditional non-source based writing respectively. Based on the analysis, the major findings are obtained as follows. Firstly, task-based cooperative writing could effectively cultivate college students’ critical thinking abilities in general and students’ critical thinking affective disposition and cognitive skill to a significant degree in particular; Secondly, as for the 7 critical thinking sub-dispositions, the analyticity is improved to a significant level while CT-confidence, inquisitiveness, truth-seeking, maturity, open-mindedness and systematicity are not significantly enhanced. And as for the 6 critical thinking sub-skills, interpretation, explanation, inference, and analysis are all developed to a significant extent while self-regulation failed to reach the significant level; Finally, students’ writing proficiency is also promoted. College students’ critical thinking ability is positively and significantly correlated with their writing proficiency. Among the critical thinking sub-dispositions, there exists a positive correlation between students’ writing quality and truth-seeking as well as maturity. And the correlations between the writing quality and all the critical thinking sub-skills are positive and significant

    Three-Layered Atmospheric Structure in Accretion Disks Around Stellar-Mass Black Holes

    Get PDF
    Modeling of the x-ray spectra of the Galactic superluminal jet sources GRS 1915+105 and GRO J1655-40 reveal a three-layered atmospheric structure in the inner region of their accretion disks. Above the cold and optically thick disk of a temperature 0.2-0.5 keV, there is a warm layer with a temperature of 1.0-1.5 keV and an optical depth around 10. Sometimes there is also a much hotter, optically thin corona above the warm layer, with a temperature of 100 keV or higher and an optical depth around unity. The structural similarity between the accretion disks and the solar atmosphere suggest that similar physical processes may be operating in these different systems.Comment: 5 fives, 2 figures, 1 table. The online version of the paper in Science may be accessed through http://jet.uah.edu/~zhangsn/papers.htm

    Het tijdskrediet eindeloopbaan : verlengt het de beroepsloopbaan?

    Get PDF
    In deze studie onderzoeken we hoe deeltijds werk gekoppeld aan tijdskrediet in de private sector de kans beĂŻnvloedt om op het einde van de loopbaan aan het werk te blijven . We houden rekening met selecte deelname aan het tijdskrediet door te controleren voor een uitgebreide set van individuele kenmerken en indicatoren van de volledige arbeidsgeschiedenis van werknemers. We vinden dat het tijdskrediet de kans om aan het werk te blijven gedurende de eerste twee (vier) jaar significant verhoogt. Wanneer de begunstigden van het tijdskrediet recht krijgen op een vervroegd pensioen, keert dit positieve effect echter en treden de begunstigden vroeger uit de arbeidsmarkt dan wanneer ze geen tijdskrediet hadden opgenomen. Deze resultaten suggereren dat het tijdskrediet initieel de balans tussen werk en vrije tijd herstelt, maar dat het uiteindelijk de hechting met de arbeidsmarkt doet verliezen. Deeltijds gaan werken op het einde van de loopbaan verlaagt ook licht de kans op ziekteverzuim, maar dit effect is statistisch niet significant verschillend van nul. Een kosten-baten analyse geeft aan dat de maatschappelijke kosten over het algemeen groter zijn de baten voor de samenleving

    SARS coronavirus 7a protein blocks cell cycle progression at G0/G1 phase via the cyclin D3/pRb pathway

    Get PDF
    AbstractThe genome of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) contains four structural genes that are homologous to genes found in other coronaviruses, and also contains six subgroup-specific open reading frames (ORFs). Expression of one of these subgroup-specific genes, ORF7a, resulted in apoptosis via a caspase-dependent pathway. Here, we observed that transient expression of ORF7a protein fused with myc or GFP tags at its N or C terminus inhibited cell growth and prevented BrdU incorporation in different cultural cells, suggesting that ORF7a expression may regulate cell cycle progression. Analysis by flow cytometry demonstrated that ORF7a expression was associated with blockage of cell cycle progression at G0/G1 phase in HEK 293 cells after 24 to 60 h post-transfection. Similar results were observed in COS-7 and Vero cells. Mutation analysis of ORF7a revealed that the domain spanning aa 44–82 of 7a protein was essential for its cytoplasmic localization and for induction of the cell cycle arrest. After analyzing the cellular proteins involving in regulation of cell cycle progression, we demonstrated that ORF7a expression was correlated with a significant reduction of cyclin D3 level of mRNA transcription and expression, and phosphorylation of retinoblastoma (Rb) protein at ser795 and ser809/811, not with the expression of cyclin D1, D2, cdk4 and cdk6 in HEK 293 cells. These results suggest that the insufficient expression of cyclin D3 may cause a decreased activity of cyclin D/cdk4/6, resulting in the inhibition of Rb phosphorylation. Accumulation of hypo- or non-phosphorylated pRb thus prevents cell cycle progression at G0/G1 phase

    Research progress of Claudin-low breast cancer

    Get PDF
    Claudin-low breast cancer (CLBC) is a subgroup of breast cancer discovered at the molecular level in 2007. Claudin is one of the primary proteins that make up tight junctions, and it plays crucial roles in anti-inflammatory and antitumor responses as well as the maintenance of water and electrolyte balance. Decreased expression of claudin results in the disruption of tight junction structures and the activation of downstream signaling pathways, which can lead to tumor formation. The origin of Claudin-low breast cancer is still in dispute. Claudin-low breast cancer is characterized by low expression of Claudin3, 4, 7, E-cadherin, and HER2 and high expression of Vimentin, Snai 1/2, Twist 1/2, Zeb 1/2, and ALDH1, as well as stem cell characteristics. The clinical onset of claudin-low breast cancer is at menopause age, and its histological grade is higher. This subtype of breast cancer is more likely to spread to lymph nodes than other subtypes. Claudin-low breast cancer is frequently accompanied by increased invasiveness and a poor prognosis. According to a clinical retrospective analysis, claudin-low breast cancer can achieve low pathological complete remission. At present, although several therapeutic targets of claudin-low breast cancer have been identified, the effective treatment remains in basic research stages, and no animal studies or clinical trials have been designed. The origin, molecular biological characteristics, pathological characteristics, treatment, and prognosis of CLBC are extensively discussed in this article. This will contribute to a comprehensive understanding of CLBC and serve as the foundation for the individualization of breast cancer treatment

    An Advanced Adaptive Control of Lower Limb Rehabilitation Robot

    Get PDF
    Rehabilitation robots play an important role in the rehabilitation field, and effective human-robot interaction contributes to promoting the development of the rehabilitation robots. Though many studies about the human-robot interaction have been carried out, there are still several limitations in the flexibility and stability of the control system. Therefore, we proposed an advanced adaptive control method for lower limb rehabilitation robot. The method was devised with a dual closed loop control strategy based on the surface electromyography (sEMG) and plantar pressure to improve the robustness of the adaptive control for the rehabilitation robots. First, in the outer loop control, an advanced variable impedance controller based on the sEMG and plantar pressure was designed to correct robot's reference trajectory. Then, in the inner loop control, a sliding mode iterative learning controller (SMILC) based on the variable boundary saturation function was designed to achieve the tracking of the reference trajectory. The experiment results showed that, in the designed dual closed loop control strategy, a variable impedance controller can effectively reduce trajectory tracking errors and adaptively modify the reference trajectory synchronizing with the motion intention of patients; the designed sliding mode iterative learning controller can effectively reduce chattering in sliding mode control and excellently achieve the tracking of rehabilitation robot's reference trajectory. This study can improve the performance of the human-robot interaction of the rehabilitation robot system, and expand the application to the rehabilitation field

    Dynamic Methylation Changes of DNA and H3K4 by RG108 Improve Epigenetic Reprogramming of Somatic Cell Nuclear Transfer Embryos in Pigs

    Get PDF
    Background/Aims: DNA methylation and histone modifications are essential epigenetic marks that can significantly affect the mammalian somatic cell nuclear transfer (SCNT) embryo development. However, the mechanisms by which the DNA methylation affects the epigenetic reprogramming have not been fully elucidated. Methods: In our study, we used quantitative polymerase chain reaction (qPCR), Western blotting, immunofluorescence staining (IF) and sodium bisulfite genomic sequencing to examine the effects of RG108, a DNA methyltransferase inhibitor (DNMTi), on the dynamic pattern of DNA methylation and histone modifications in porcine SCNT embryos and investigate the mechanism by which the epigenome status of donor cells’ affects SCNT embryos development and the crosstalk between epigenetic signals. Results: Our results showed that active DNA demethylation was enhanced by the significantly improving expression levels of TET1, TET2, TET3 and 5hmC, and passive DNA demethylation was promoted by the remarkably inhibitory expression levels of DNMT1, DNMT3A and 5mC in embryos constructed from the fetal fibroblasts (FFs) treated with RG108 (RG-SCNT embryos) compared to the levels in embryos from control FFs (FF-SCNT embryos). The signal intensity of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 9 acetylation (H3K9Ac) was significantly increased and the expression levels of H3K4 methyltransferases were more than 2-fold higher expression in RG-SCNT embryos. RG-SCNT embryos had significantly higher cleavage and blastocyst rates (69.3±1.4%, and 24.72±2.3%, respectively) than FF-SCNT embryos (60.1±2.4% and 18.38±1.9%, respectively). Conclusion: Dynamic changes in DNA methylation caused by RG108 result in dynamic alterations in the patterns of H3K4me3, H3K9Ac and histone H3 lysine 9 trimethylation (H3K9me3), which leads to the activation of embryonic genome and epigenetic modification enzymes associated with H3K4 methylation, and contributes to reconstructing normal epigenetic modifications and improving the developmental efficiency of porcine SCNT embryos

    Prenatal Progestin Exposure Is Associated With Autism Spectrum Disorders

    Get PDF
    We have previously reported that prenatal progestin exposure induces autism-like behavior in offspring through ERβ (estrogen receptor β) suppression in the brain, indicating that progestin may induce autism spectrum disorders (ASD). In this study, we aim to investigate whether prenatal progestin exposure is associated with ASD. A population-based case-control epidemiology study was conducted in Hainan province of China. The ASD children were first screened with the Autism Behavior Checklist (ABC) questionnaire, and then diagnosed by clinical professionals using the ASD diagnosis criteria found in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V). Eventually, 235 cases were identified as ASD from 37863 children aged 0–6 years old, and 682 matched control subjects with typically developing children were selected for the analysis of potential impact factors on ASD prevalence using multivariate logistic regression. Our data show that the ASD prevalence rate in Hainan was 0.62% with a boy:girl ratio of 5.4:1. Interestingly, we found that the following factors were strongly associated with ASD prevalence: use of progestin to prevent threatened abortion, use of progestin contraceptives at the time of conception, and prenatal consumption of progestin-contaminated seafood during the first trimester of pregnancy. All the above factors were directly or indirectly involved with prenatal progestin exposure. Additionally, we conducted in vivo experiments in rats to further confirm our findings. Either endogenous (progesterone) or synthetic progestin (norethindrone)-treated seafood zebrafish were used to feed pregnant dams, and the subsequent offspring showed autism-like behavior, which further demonstrated that prenatal progestin exposure may induce ASD. We conclude that prenatal progestin exposure may be associated with ASD development

    Correlation Analysis Between Required Surgical Indexes and Complications in Patients With Coronary Heart Disease

    Get PDF
    A total of 215 patients with coronary heart disease (CHD) were analyzed with SPSS. Samples of different genders showed significance in the obtuse marginal branch of the left circumflex branch × 1, the diagonal branch D1 × 1, and the ms PV representation. Patients with left circumflex branch occlusion are more male and tend to be younger. Age displayed a positive correlation with left intima-media thickness (IMT) and right IMT. This indicated that as age increases, the values of left IMT and right IMT increase. Samples of different CHD types showed significance in the obtuse marginal branch of the left circumflex branch × 1, the middle part of RCA × 1, and the middle part of the left anterior descending branch × 1.5. For non-ST-segment elevation angina pectoris with acute total vascular occlusion, the left circumflex artery is the most common, followed by the right coronary artery and anterior descending branch. Ultrasound of carotid IMT in patients with CHD can predict changes in left ventricular function, but no specific correlation between left and right common carotid IMT was found. Samples with or without the medical history of ASCVD showed significance in the branch number of coronary vessel lesions. The value of the branch number of coronary vessel lesions in patients with atherosclerotic cardiovascular disease (ASCVD) was higher than in those without ASCVD. The occurrence of complication is significantly relative with the distance of left circumflex branch × 1, the middle segment of left anterior descending branch × 1.5, and the distance of left anterior descending branch × 1. For patients without complications, the values in the distal left circumflex branch × 1, the middle left anterior descending branch × 1.5, and the distal left anterior descending branch × 1 were higher than those for patients with complications. The VTE scores showed a positive correlation with the proximal part of RCA × 1, the branch number of coronary vessel lesions, the posterior descending branch of left circumflex branch × 1, the distal part of left circumflex branch × 1, and the middle part of left anterior descending branch × 1.5
    • …
    corecore