Asynchronous discussions have been widely used in education to support learning. Exploring the reasons why threads in asynchronous discussion forums die may help us improve our understanding of ...asynchronous discussions and lead to a more effective learning process. This study explored why threads in asynchronous discussion forums shut down. Two analytical methods, namely, content analysis and statistical analysis, were employed. The discussion postings were coded into various behavior patterns based on the work of Lu et al. (Computers in Human Behavior 27:946–955, 2011). Differences of behavior patterns between long lifespan threads and short lifespan threads were investigated and reasons why some threads die quickly was explored. The shortest lifespan threads that died after one or two comments were statistically analyzed. The results showed that there was a significant difference in the disagreement with added justification between long lifespan threads and short lifespan threads. Explanation oriented questions, disagreement against justification, fact oriented questions, new claim, thumbs up and thanks, to some extent, were significantly different between long lifespan threads and short lifespan threads. Agreement played a large part in shortest lifespan threads. Based on the results and further content analysis, many educational implications have emerged for designing asynchronous discussion activities and asynchronous discussion rules. For example, it is necessary to continuously encourage learners to express fresh ideas; rewards can be a way of encouraging high quality replies; learners need to give the reason or explanation why they agree or disagree with others’ postings; learners should be encouraged to ask more explanatory questions or factual questions; and off topic comments should not be forbidden.
The Gram-negative opportunistic pathogen
Pseudomonas aeruginosa
possesses hierarchical quorum sensing (QS) systems. The intricate QS network of
P. aeruginosa
synchronizes a suite of virulence ...factors, contributing to the mortality and morbidity linked to the pathogenicity of this bacterium. Previous studies have revealed that variations in the
lasR
gene are frequently observed in chronic isolates of cystic fibrosis (CF). Specifically, LasR
Q45stop
was identified as a common variant among CF,
lasR
mutants during statistical analysis of the clinical
lasR
mutants in the database. In this study, we introduced LasR
Q45stop
into the chromosome of
P. aeruginosa
PAO1 through allelic replacement. The social traits of PAO1 LasR
Q45stop
were found to be equivalent to those of PAO1 LasR-null isolates. By co-evolving with the wild-type in caseinate broth, elastase-phenotypic-variability variants were derived from the LasR
Q45stop
subpopulation. Upon further examination of four LasR
Q45stop
sublines, we determined that the variation of T2SS-peptidase
xcpA
and
mexT
genes plays a pivotal role in the divergence of various phenotypes, including public goods elastase secretion and other pathogenicity traits. Furthermore, XcpA mutants demonstrated a fitness advantage compared to parent strains during co-evolution. Numerous phenotypic variations were associated with subline-specific genetic alterations. Collectively, these findings suggest that even within the same parental subline, there is ongoing microevolution of individual mutational trajectory diversity during adaptation.
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•MGP was prepared by simple anionic intercalation.•Excellent removal effect on both industrial wastewater and groundwater.•The removal rates of Mn2+ can reach 99.27 % in practical ...applications.•Low operating voltage and energy consumption.
Effective removal of excess manganese ions (Mn2+) from water is urgently needed to maintain human health and ecological balance. To date, electrochemical deposition (ED) techniques have been widely used for their simplicity and flexibility, while the active surface area and reliability of electrodes are still major issues. Herein, modified graphite papers (MGP) fabricated by the anionic intercalation method were used as the working electrode to remove Mn2+ from wastewater via the electrochemical deposition method. The results showed that the highest removal of Mn2+ by MGP-E was achieved when the voltage was 1.0 V, the deposition time was 6 h, and the pH value of the wastewater was 3.0. Under the above parameters, the removal rate of Mn2+ in simulated wastewater can reach over 99.73 %, while the removal rates in industrial wastewater and groundwater can reach 96.20 % and 99.27 %, respectively, which can meet the standard of water treatment. The related tests confirmed that the deposition process had excellent cycling stability and low energy consumption. This study may provide an economical, sustainable and efficient electrode material for Mn2+ removal from industrial wastewater and groundwater via electrochemical deposition technology.
Compared with CaAlg, Cu2+/CaAlg had stronger mechanical properties, high flux and lower swelling rate. Cu2+/CaAlg showed good antibacterial properties and can be used for a long time.
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...Herein, copper ion doped calcium alginate (Cu2+/CaAlg) composite hydrogel filtration membranes were prepared by using natural polymer sodium alginate (NaAlg) as raw material. The thermal stability and structure of the composite membranes were characterized by thermogravimetric analysis and infrared spectroscopy. The mechanical strength, anti-fouling performance, hydrophilicity and filtration performance of the membrane were studied. The results show that Cu2+/CaAlg hydrogel membrane has excellent mechanical properties and thermal stability. The anti-swelling ability of the membrane was greatly enhanced by doping Cu2+. After three alternate filtration cycles, the flux recovery rate of Cu2+/CaAlg hydrogel membrane can still reach 85%, indicating that the membrane has good anti-pollution performance. When the operation pressure was 0.1 MPa, the rejection of coomassie brilliant blue G250 reached 99.8% with a flux of 46.3 L m−2 h−1, while the Na2SO4 rejection was less than 10.0%. The Cu2+/CaAlg membrane was recycled after 24 h in the filtration process, and its flux and rejection rate did not decrease significantly, indicating that the hydrogel membrane has long-term application potential. The Cu2+/CaAlg membrane has a wide range of applications prospect in dye desalination, fine separation and biopharmaceutical technology fields.
In order to solve the problem where existing mode-matching methods in microelectromechanical systems (MEMS) vibrating gyroscopes fail to meet real-time and reliability requirements, this paper ...presents a novel method to accomplish automatic and real-time mode-matching based on phase-shifted 45° additional force demodulation (45° AFD-RM). The phase-shifted 45° additional force signal has the same frequency as the quadrature force signal, but it is phase-shifted by 45° and applied to the sense mode. In addition, two-way phase-shifted 45° demodulations are used at the sense-mode detection output to obtain a phase metric that is independent of the Coriolis force and can reflect the mode-matching state. Then, this phase metric is used as a control variable to adaptively control the tuning voltage, so as to change the sense-mode frequency through the negative stiffness effect and ultimately achieve real-time mode-matching. Simulation and experimental results show that the proposed 45° AFD-RM method can achieve real-time matching. The mode frequency split is controlled within 0.1 Hz, and the gyroscope scale factor, zero-bias instability, and angle random walk are effectively improved.
This study presents an innovative physical isolation measure for commercial scenarios, namely, hanging curtains, to prevent the spread of respiratory infections. Using computational fluid dynamics ...simulation techniques, the closed spaces within cruise cabins were modeled and numerically analyzed, focusing on the dispersion characteristics of droplets. Additionally, orthogonal methods were employed to investigate various arrangements of hanging curtains and their effects on droplet dispersion based on spatial positioning. The research findings indicated that hanging curtains can effectively alter the airflow within a space, realizing the innovative concept of localized pollutant containment. It was found that the spatial partitioning method based on the location of individuals contributes more to reducing droplet dispersion than other methods. Moreover, the sag height of curtains emerges as the most influential factor on individual infection risk, while the scheme for hanging curtain positions has the least impact. Finally, the optimal configuration recommendation is provided: a curtain bottom coordinate of Z = 2.3 m and a top coordinate of Z = 2.8 m when the infection source was positioned at the center of the space. This configuration has also been validated by varying the location of the infection source. The research findings provide valuable insights for formulating preventive measures for passengers on cruise ships and for pandemic control in similar scenarios.
Tripartite Motif 29 (TRIM29) has been newly identified as being implicated in cancer progression. However, the biological role and molecular mechanism of TRIM29 in the invasion and metastasis of ...colorectal cancer (CRC) remain to be determined.
The expression levels of TRIM29 and β-catenin in CRC patient specimens were detected by immunohistochemistry. Recombinant lentivirus vectors containing the TRIM29 gene and its small hairpin interfering RNAs were constructed and transduced into CRC cells. Wound-healing and Transwell assays were performed to evaluate the migration and invasion abilities of CRC cells in vitro. Hepatic metastasis models in nude mice were established to validate the function of TRIM29 in vivo. Moreover, the expressions of epithelial-to-mesenchymal transition (EMT)-associated proteins were detected by qRT-PCR and Western blotting in CRC cells. Finally, Western blotting, qRT-PCR, luciferase reporter assays, and immunofluorescence assays were used to explore the molecular mechanisms of TRIM29 in CRC progression.
Increased TRIM29 expression positively correlated with lymph node metastasis and β-catenin expression in patient CRC tissues. Overexpression of TRIM29 promoted invasion and metastasis of CRC cells in vitro and in vivo by regulating EMT, whereas the knockdown of TRIM29 had the opposite effect. Further mechanistic studies suggest that TRIM29 can activate the Wnt/β-catenin signaling pathway via up-regulating CD44 expression in colorectal cancer.
TRIM29 induces EMT through activating the Wnt/β-catenin signaling pathway via up-regulating CD44 expression, thus promoting invasion and metastasis of CRC.
Thermal management systems for lithium-ion batteries based on the cooling and heating of phase change materials have become a popular research topic. However, the low thermal conductivity, flame ...resistance, high and low temperature adaptability of phase change materials, as well as the thermal runaway mechanisms and lightweight design of phase change material-based systems remain to be explored. The aim of this paper is to conduct a publication-wide macro bibliometric review on thermal management systems for lithium-ion batteries based on phase change material to date. Total of 583 associated publications were retrieved from the Web of Science Core Collection database for the period 2006–2022. A bibliometric study was conducted through the visualization software VOSviewer. The findings were derived from annual publication trends, geographical and institutional distribution, authors and their collaborative networks, keyword network analysis and analysis of highly cited publications as well as reference co-citation analysis. The findings provide a comprehensive overview of the evolution of research hotspots in the field and can help researchers who would like to work in the field to quickly grasp the research frontiers and the overall picture. Furthermore, some suggestions for future work are summarized.
The translation of Intangible Cultural Heritage (ICH) terms is an important practical aspect of cross-lingual expressions related to ICH knowledge. Chinese ICH terms are heavily loaded with specific ...historical and cultural knowledge and regional characteristics. Based on cognitive psychology, this paper analyzes the metonymic mechanism of traditional translation techniques such as substitution in the English translation of Chinese ICH terms. The English translation of Chinese ICH nominal terms can be realized based on the metonymic mechanism of replacing either a superordinate with a subordinate of the linguistic structure or a subordinate of the linguistic structure with a subordinate of the linguistic structure in the pair language, English-Chinese. The English translation of Chinese ICH verbal terms can regard the whole verbal action as an event process and can highlight one aspect of the process through a metonymic mechanism as well. This paper holds that metonymy is an important psychological motivation and cognitive mechanism for translation skills such as substitution as it brings the relationship between the corresponding items of the target language and the source language into a unified interpretation framework. Hence, this may add some significance to the research of translation theory and translation practice. This also contributes to the UN Sustainable Development Goal number 17 which seeks global parternship for sustainable development.
COVID-19 is a respiratory infectious disease that spreads readily between people, and an urgent issue of passengers’ exposure risk assessment in commercial aircraft has been raised because an ...aircraft cabin as a confined space may carry and transmit the disease worldwide. In this study, the droplets transmission process under different ventilation systems in a twin-aisle wide-body aircraft was studied using CFD simulations and the infection risk of passengers was assessed by the improved Wells–Riley model. Numerical results found that the transmission mechanism of droplets in the aircraft cabin was different depending on the type of ventilation systems and the location of the infectious source. Annular airflow could effectively enhance the ability of droplets transmission, while direct airflow, represented by displacement ventilation, could significantly inhibit droplets transmission. Accordingly, a new type of ventilation system was proposed based on the concept that the overall space is organized by annular airflow and the local area is direct airflow. Compared with sidewall mixing ventilation system, the infection risk of the new ventilation system presented in this study is reduced by 27%.
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