391 research outputs found

    A Study of Developing a System Dynamics Model for the Learning Effectiveness Evaluation

    Get PDF
    [[abstract]]This study used the research method of system dynamics and applied the Vensim software to develop a learning effectiveness evaluation model. This study developed four cause-and-effect chains affecting learning effectiveness, including teachers’ teaching enthusiasm, family involvement, school’s implementation of scientific activities, and creative teaching method, as well as the system dynamics model based on the four cause-and-effect chains. Based on the developed system dynamic model, this study performed simulation to investigate the relationship among family involvement, learning effectiveness, teaching achievement, creative teaching method, and students’ learning interest. The results of this study verified that there are positive correlations between family involvement and students’ learning effectiveness, as well as students’ learning effectiveness and teachers’ teaching achievements. The results also indicated that the use of creative teaching method is able to increase students’ learning interest and learning achievement.[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]US

    Tourniquet Use in Total Knee Arthroplasty

    Get PDF
    The use of an intraoperative tourniquet for total knee arthroplasty (TKA) is a common practice. Although it provides clear filed and ideal cementation during surgery, issues regarding the effectiveness, drawbacks and complications are still investigated. This review was conducted to evaluate the role of tourniquet in TKA through a comprehensive literature search was done in PubMed Medicine, Embase, and other internet database. Debating issues, including the blood loss, operation time, alignment, compromised wound healing, quadriceps weakness and timing of release were furtherly examined. Based on our prior work and the general consensus that the tourniquet should be set with the lowest pressure and for the least ischemic time possible, we recommend early tourniquet release right after the closure of extensor mechanism in the TKAs without drainage

    The active oxygen species promoted catalytic oxidation of 5-hydroxymethyl-2-furfural on facet-specific Pt nanocrystals

    Get PDF
    This work was supported by Natural Science Foundation of Tianjin (Grant No. 17JCYBJC22600) and the Fundamental Research Funds for the Central Universities.The aerobic oxidation of alcohols and aldehydes over noble metal catalysts is a critical reaction for the catalytic conversion of carbohydrates into value-added chemicals from biomass. However, to fully understand the reaction mechanism, in particular the role of O2 and the generated active oxygen species in these reactions is still a challenging target. In the present work, the sub-10 nm Pt nanocrystals with cubic (Pt-NCs), octahedral (Pt-NOs) and spherical (Pt-NSs) morphologies were synthesized and used as catalysts in aerobic oxidation of HMF. Through experimental and computational investigations, the facet-dependent O2 conversion pathway and catalytic oxidation performance were discussed. The molecular O2 tends to be dissoci-ated to generate •OH on Pt(100) surface, but prefers to be reduced to •O2- on Pt(111) surface. Moreover, Pt-NCs enclosed by the {100} facets exhibited significantly enhanced catalytic activity than Pt-NOs enclosed by the {111} facets and Pt-NSs, in particular for alcohol oxidation step. Based on the experimental data and density functional theory (DFT) calculations, an active oxygen species promoted dehydrogenation mechanism for aerobic oxidation of HMF was proposed. The dehydrogena-tion of alcohol group is more favourable on the Pt(100) surface with an assistance of •OH, which are the dominant active oxygen species on the Pt(100) surface. We anticipate that this work would provide a new insight into the role of active oxy-gen species in aerobic oxidation of alcohols and aldehydes over noble metal catalysts.PostprintPeer reviewe

    Irreducible Elbow Dislocation Associated with Hill–Sachs-like Lesion over the Capitellum

    Get PDF
    Irreducible dislocation of the elbow is an uncommon event. We present the case of a posterolateral elbow dislocation after a fall injury in a 67-year-old woman. A closed reduction performed in the emergency department was unsuccessful since the limited passive range of motion resulted in difficulty to perform longitudinal traction and flexion. Computed tomography images showed that the posterolateral aspect of the capitellum was impacted by the tip of the coronoid process, thus appearing similar to the Hill–Sachs lesion in the humeral head. Subsequent open reduction of the elbow revealed the dislocation to be irreducible since the tip of the coronoid process had wedged into a triangular Hill–Sachs-like lesion in the capitellum. The joint was reduced by providing distal traction on the forearm, and main fragments were disengaged using digital pressure. At the 3-month follow-up, the patient reported no dislocations, and had an acceptable range of motion. Thus, we propose that to avoid iatrogenic injury to the joint or other nearby structures, irreducible dislocations should not be subjected to repeated manipulation

    Effect of Antrodia

    Get PDF
    Antrodia camphorata is a rare Taiwanese medicinal mushroom. Antrodia camphorata extract has been reported to exhibit antioxidant, anti-inflammation, antimetastasis, and anticancer activities and plays a role in liver fibrosis, vasorelaxation, and immunomodulation. Critical vascular inflammation leads to vascular dysfunction and cardiovascular diseases, including abdominal aortic aneurysms, hypertension, and atherosclerosis. Platelet activation plays a crucial role in intravascular thrombosis, which is involved in a wide variety of cardiovascular diseases. However, the effect of Antrodia camphorata on platelet activation remains unclear. We examined the effects of Antrodia camphorata on platelet activation. In the present study, Antrodia camphorata treatment (56–224 μg/mL) inhibited platelet aggregation induced by collagen, but not U46619, an analogue of thromboxane A2, thrombin, and arachidonic acid. Antrodia camphorata inhibited collagen-induced calcium (Ca2+) mobilization and phosphorylation of protein kinase C (PKC) and Akt. In addition, Antrodia camphorata significantly reduced the aggregation and phosphorylation of PKC in phorbol-12, 13-dibutyrate (PDBu) activated platelets. In conclusion, Antrodia camphorata may inhibit platelet activation by inhibiting of Ca2+ and PKC cascade and the Akt pathway. Our study suggests that Antrodia camphorata may be a potential therapeutic agent for preventing or treating thromboembolic disorders

    Faba Bean (Vicia faba L.) Nodulating Rhizobia in Panxi, China, Are Diverse at Species, Plant Growth Promoting Ability, and Symbiosis Related Gene Levels

    Get PDF
    We isolated 65 rhizobial strains from faba bean (Vicia faba L.) from Panxi, China, studied their plant growth promoting ability with nitrogen free hydroponics, genetic diversity with clustered analysis of combined ARDRA and IGS-RFLP, and phylogeny by sequence analyses of 16S rRNA gene, three housekeeping genes and symbiosis related genes. Eleven strains improved the plant shoot dry mass significantly comparing to that of not inoculated plants. According to the clustered analysis of combined ARDRA and IGS-RFLP the isolates were genetically diverse. Forty-one of 65 isolates represented Rhizobium anhuiense, and the others belonged to R. fabae, Rhizobium vallis, Rhizobium sophorae, Agrobacterium radiobacter, and four species related to Rhizobium and Agrobacterium. The isolates carried four and five genotypes of nifH and nodC, respectively, in six different nifH-nodC combinations. When looking at the species-nifH-nodC combinations it is noteworthy that all but two of the six R. anhuiense isolates were different. Our results suggested that faba bean rhizobia in Panxi are diverse at species, plant growth promoting ability and symbiosis related gene levels.Peer reviewe

    A Pair of Early- and Late-Forming Galaxy Cluster Samples: Implications for Detection of Halo Assembly Bias

    Full text link
    The halo assembly bias, a phenomenon referring to dependencies of the large-scale bias of a dark matter halo other than its mass, is a fundamental property of our standard cosmological model. First discovered in 2005 via high-resolution numerical simulations, it has been proven very difficult to be detected observationally, with only a few convincing claims of detection thus far. The main obstacle lies in finding an accurate proxy of the halo formation time. In this study, by utilizing a constrained simulation that can faithfully reproduce the observed structures larger than ∼2 \sim 2\,Mpc in the local universe, for a sample of about 630 massive clusters at z≤0.12z\le 0.12, we find their counterpart halos in the simulation and use the mass growth history of the matched halos to estimate the formation time of the observed clusters. This allows us to construct a pair of early- and late-forming clusters, with similar mass as measured via weak gravitational lensing, and large-scale bias differing at ≳4σ\gtrsim 4\sigma level, clearly showing the signature of assembly bias.Comment: MNRAS letters, submitted; 5 pages and 3 figure

    The role of Bi-doping in promoting electron transfer and catalytic performance of Pt/3DOM-Ce1-xBixO2-δ

    Get PDF
    We thank Prof. J.-Q. Yu for a useful discussion. This work was supported by Tianjin Municipal Natural Science Foundation (Grant 17JCYBJC22600), China Scholarship Council (Grants 201606200096 and 201606200087), and the Fundamental Research Funds for the Central Universities. Computational support was provided by the Beijing Computing Center (BCC).Investigation of Bi-doping effects on the catalytic performance of Pt/3DOM-Ce1−xBixO2−δ in the aerobic oxidation of 5-hydroxymethyl-2-furfural allows us to reveal the promoted catalytically active sites: the asymmetrical oxygen vacancies coordinated with one Bi and up to three Ce cations, such as Bi-□(-Ce)3, where □ represents an oxygen vacancy, which can easily gain oxygen atoms in favor of the CeO2 structure, and, when filled with oxygen, easily release oxygen anions in favor of six-coordination for Bi3+. The loss of electrons in the reduction of oxygen atoms at these sites would be replenished by electron transfer from Pt nanoparticles eventually promoting the oxidation potential of the Pt nanoparticles. The present work points out that the promoted catalytic properties in Bi-doped CeO2 are mainly due to the asymmetric structures of the oxygen vacancies, rather than simply to the number of oxygen vacancies. The newly proposed model of asymmetrical active sites and electron transfer mechanism may shed light on the physicochemical properties of other solid solution substrate-supported  metal nanoparticle catalysts.PostprintPeer reviewe
    • …
    corecore