Do learning by teaching environments with metacognitive support help students develop better learning behaviors

We have developed Teachable Agent environments that use learning by teaching with metacognitive support to help middle school students learn about complex science topics. To demonstrate the effectiveness of this approach, we have run studies that compare three systems where (i) students are taught by an agent, (ii) students teach a computer agent, and (iii) students teach a computer agent and receive metacognitive support while teaching. Students ’ activities on the system, captured in log files, were coded using six primary learning activities. In this paper, we analyze behavior fragments systematically derived from the activity sequences, and identify behaviors that correlate well with high and low student performance. Our results show that students who teach and receive metacognitive support exhibit more of the high performing behaviors than the other two groups

Audiovisual n-Back Training Alters the Neural Processes of Working Memory and Audiovisual Integration: Evidence of Changes in ERPs

(1) Background: This study investigates whether audiovisual n-back training leads to training effects on working memory and transfer effects on perceptual processing. (2) Methods: Before and after training, the participants were tested using the audiovisual n-back task (1-, 2-, or 3-back), to detect training effects, and the audiovisual discrimination task, to detect transfer effects. (3) Results: For the training effect, the behavioral results show that training leads to greater accuracy and faster response times. Stronger training gains in accuracy and response time using 3- and 2-back tasks, compared to 1-back, were observed in the training group. Event-related potentials (ERPs) data revealed an enhancement of P300 in the frontal and central regions across all working memory levels after training. Training also led to the enhancement of N200 in the central region in the 3-back condition. For the transfer effect, greater audiovisual integration in the frontal and central regions during the post-test rather than pre-test was observed at an early stage (80-120 ms) in the training group. (4) Conclusion: Our findings provide evidence that audiovisual n-back training enhances neural processes underlying a working memory and demonstrate a positive influence of higher cognitive functions on lower cognitive functions

Efficient overall water splitting in acid with anisotropic metal nanosheets

超高効率な水の電気分解を実現するナノシート状合金触媒を開発 --再生可能エネルギーによる水素社会実現へ大きく貢献--. 京都大学プレスリリース. 2021-02-17.Water is the only available fossil-free source of hydrogen. Splitting water electrochemically is among the most used techniques, however, it accounts for only 4% of global hydrogen production. One of the reasons is the high cost and low performance of catalysts promoting the oxygen evolution reaction (OER). Here, we report a highly efficient catalyst in acid, that is, solid-solution Ru‒Ir nanosized-coral (RuIr-NC) consisting of 3 nm-thick sheets with only 6 at.% Ir. Among OER catalysts, RuIr-NC shows the highest intrinsic activity and stability. A home-made overall water splitting cell using RuIr-NC as both electrodes can reach 10 mA cm−2geo at 1.485 V for 120 h without noticeable degradation, which outperforms known cells. Operando spectroscopy and atomic-resolution electron microscopy indicate that the high-performance results from the ability of the preferentially exposed {0001} facets to resist the formation of dissolvable metal oxides and to transform ephemeral Ru into a long-lived catalyst

Phase Control of Solid-Solution Nanoparticles beyond the Phase Diagram for Enhanced Catalytic Properties

The crystal structure, which intrinsically affects the properties of solids, is determined by the constituent elements and composition of solids. Therefore, it cannot be easily controlled beyond the phase diagram because of thermodynamic limitations. Here, we demonstrate the first example of controlling the crystal structures of a solid-solution nanoparticle (NP) entirely without changing its composition and size. We synthesized face-centered cubic (fcc) or hexagonal close-packed (hcp) structured PdxRu₁–x NPs (x = 0.4, 0.5, and 0.6), although they cannot be synthesized as bulk materials. Crystal-structure control greatly improves the catalytic properties; that is, the hcp-PdxRu₁–x NPs exceed their fcc counterparts toward the oxygen evolution reaction (OER) in corrosive acid. These NPs only require an overpotential (η) of 200 mV at 10 mA cm⁻², can maintain the activity for more than 20 h, greatly outperforming the fcc-Pd₀.₄Ru₀.₆ NPs (η = 280 mV, 9 min), and are among the most efficient OER catalysts reported. Synchrotron X-ray-based spectroscopy, atomic-resolution electron microscopy, and density functional theory (DFT) calculations suggest that the enhanced OER performance of hcp-PdRu originates from the high stability against oxidative dissolution

Twenty-four-hour ambulatory blood pressure variability and association with ischemic stroke subtypes in the subacute stage

Background and purposeBlood pressure (BP) variability (BPV) increases the risk of cerebral disease in both hemorrhagic and ischemic strokes. However, whether BPV is associated with different types of ischemic stroke remains unclear. In this study, we explored the relationship between BPV and ischemic stroke subtypes.MethodsWe enrolled consecutive patients aged 47–95 years with ischemic stroke in the subacute stage. We categorized them into four groups based on their artery atherosclerosis severity, brain magnetic resonance imaging markers, and disease history: large-artery atherosclerosis, branch atheromatous disease, small-vessel disease, and cardioembolic stroke. Twenty-four-hour ambulatory blood pressure monitoring was performed, and the mean systolic blood pressure/diastolic blood pressure, standard deviation, and coefficient of variation were calculated. A multiple logistic regression model and random forest were used to test the relationship between BP and BPV in the different types of ischemic stroke.ResultsA total of 286 patients, including 150 men (73.0 ± 12.3 years) and 136 women (77.8 ± 9.6 years) were included in the study. Of these, 86 (30.1%) patients had large-artery atherosclerosis, 76 (26.6%) had branch atheromatous disease, 82 (28.7%) had small-vessel disease, and 42 (14.7%) had cardioembolic stroke. There were statistically significant differences in BPV between subtypes of ischemic stroke in 24-h ambulatory blood pressure monitoring. The random forest model showed that BP and BPV were important features associated with ischemic stroke. Multinomial logistic regression analysis demonstrated that systolic blood pressure levels; systolic blood pressure variability at 24 h, daytime and nighttime; and nighttime diastolic blood pressure were independent risk factors for large-artery atherosclerosis after adjustment for confounders. When compared to branch atheromatous disease and small-vessel disease, nighttime diastolic blood pressure and standard deviation of diastolic blood pressure were significantly associated with patients in the cardioembolic stroke group. However, a similar statistical difference was not seen in patients with large-artery atherosclerosis.ConclusionThe results of this study indicate a discrepancy in blood pressure variability among different ischemic stroke subtypes during the subacute stage. Higher systolic blood pressure and systolic blood pressure variability during the 24 h, daytime, and nighttime, and nighttime diastolic blood pressure were independent predictors for large-artery atherosclerosis stroke. Increased nighttime diastolic BPV was an independent risk factor for cardioembolic stroke

Laboratory scale optimization of alkali pretreatment for improvingenzymatic hydrolysis of sweet sorghum bagasse

Sweet sorghum has been identified as a promising feedstock for biological conversion to fuels as wellas other chemicals. The lignocellulosic stalk of sweet sorghum, called sweet sorghum bagasse (SSB) isa potential source of lignocellulosic biofuel. The primary goal of this study was to determine optimalalkali (lime: Ca(OH)2and lye: NaOH) pretreatment conditions to obtain higher yield of total reducingsugar while reducing the lignin content for biofuel production from SSB. Biomass conversion and ligninremoval were simultaneously optimized through four quadratic models analyzed by response surfacemethodology (RSM). The optimal conditions for lime pretreatment was 1.7% (w/v) lime concentration,6.0% (w/v) SSB loading, 2.4 h pretreatment time with predicted yields of 85.6 total biomass conversionand 35.5% lignin reduction. For lye pretreatment, 2% (w/v) alkali, 6.8% SSB loading and 2.3 h durationwere the optimal levels with predicted biomass conversion and lignin reduction of 92.9% and 50.0%,respectively. More intensive pretreatment conditions removed higher amounts of hemicelluloses andcellulose. Fourier transform infrared spectroscopy (FTIR) spectrum and scanning electron microscope(SEM) image revealed compositional and microstructural changes caused by the alkali pretreatment

Genotyping and biofilm formation of Mycoplasma hyopneumoniae and their association with virulence

Mycoplasma hyopneumoniae, the causative agent of swine respiratory disease, demonstrates differences in virulence. However, factors associated with this variation remain unknown. We herein evaluated the association between differences in virulence and genotypes as well as phenotype (i.e., biofilm formation ability). Strains 168 L, RM48, XLW-2, and J show low virulence and strains 232, 7448, 7422, 168, NJ, and LH show high virulence, as determined through animal challenge experiments, complemented with in vitro tracheal mucosa infection tests. These 10 strains with known virulence were then subjected to classification via multilocus sequence typing (MLST) with three housekeeping genes, P146-based genotyping, and multilocus variable-number tandem-repeat analysis (MLVA) of 13 loci. MLST and P146-based genotyping identified 168, 168 L, NJ, and RM48 as the same type and clustered them in a single branch. MLVA assigned a different sequence type to each strain. Simpson’s index of diversity indicates a higher discriminatory ability for MLVA. However, no statistically significant correlation was found between genotypes and virulence. Furthermore, we investigated the correlation between virulence and biofilm formation ability. The strains showing high virulence demonstrate strong biofilm formation ability, while attenuated strains show low biofilm formation ability. Pearson correlation analysis revealed a significant positive correlation between biofilm formation ability and virulence. To conclude, there was no association between virulence and our genotyping data, but virulence was found to be significantly associated with the biofilm formation ability of M. hyopneumoniae

Cathepsin K activity controls cardiotoxin‐induced skeletal muscle repair in mice

Abstract Background: Cathepsin K (CatK) is a widely expressed cysteine protease that has gained attention because of its enzymatic and non‐enzymatic functions in signalling. Here, we examined whether CatK‐deficiency (CatK−/−) would mitigate injury‐related skeletal muscle remodelling and fibrosis in mice, with a special focus on inflammation and muscle cell apoptosis. Methods: Cardiotoxin (CTX, 20 μM/200 μL) was injected into the left gastrocnemius muscle of male wild‐type (CatK+/+) and CatK−/− mice, and the mice were processed for morphological and biochemical studies. Results: On post‐injection Day 14, CatK deletion ameliorated muscle interstitial fibrosis and remodelling and performance. At an early time point (Day 3), CatK−/− reduced the lesion macrophage and leucocyte contents and cell apoptosis, the mRNA levels of monocyte chemoattractant protein‐1, toll‐like receptor‐2 and toll‐like receptor‐4, and the gelatinolytic activity related to matrix metalloproteinase‐2/‐9. CatK deletion also restored the protein levels of caspase‐3 and cleaved caspase‐8 and the ratio of the BAX to the Bcl‐2. Moreover, CatK deficiency protected muscle fibre laminin and desmin disorder in response to CTX injury. These beneficial muscle effects were mimicked by CatK‐specific inhibitor treatment. In vitro experiments demonstrated that pharmacological CatK inhibition reduced the apoptosis of C2C12 mouse myoblasts and the levels of BAX and caspase‐3 proteins induced by CTX. Conclusions: These results demonstrate that CatK plays an essential role in skeletal muscle loss and fibrosis in response to CTX injury, possibly via a reduction of inflammation and cell apoptosis, suggesting a novel therapeutic strategy for the control of skeletal muscle diseases by regulating CatK activity

Increased Functional Brain Network Efficiency During Audiovisual Temporal Asynchrony Integration Task in Aging

Audiovisual integration significantly changes over the lifespan, but age-related functional connectivity in audiovisual temporal asynchrony integration tasks remains underexplored. In the present study, electroencephalograms (EEGs) of 27 young adults (22–25 years) and 25 old adults (61–76 years) were recorded during an audiovisual temporal asynchrony integration task with seven conditions [auditory (A), visual (V), AV, A50V, A100V, V50A and V100A]. We calculated the phase lag index (PLI)-weighted connectivity networks modulated by the audiovisual tasks and found that the PLI connections showed obvious dynamic changes after stimulus onset. In the theta (4–7 Hz) and alpha (8–13 Hz) bands, the AV and V50A conditions induced stronger functional connections and higher global and local efficiencies, reflecting a stronger audiovisual integration effect, which was attributed to the auditory information arriving at the primary auditory cortex earlier than the visual information reaching the primary visual cortex. Importantly, the functional connectivity and network efficiencies of old adults revealed higher global and local efficiencies and higher degree in both the theta and alpha bands. These larger network efficiencies indicated that old adults might experience more difficulties in attention and cognitive control during the audiovisual integration task with temporal asynchrony than young adults. There were significant associations between network efficiencies and peak time of integration only in young adults. We propose that an audiovisual task with multiple conditions might arouse the appropriate attention in young adults but would lead to a ceiling effect in old adults. Our findings provide new insights into the network topography of old adults during audiovisual integration and highlight higher functional connectivity and network efficiencies due to greater cognitive demand