Load Levels Research Articles

A Light-Powered In Vitro Synthetic Enzymatic Biosystem for the Synthesis of 3-Hydroxypropionic Acid via CO2 Fixation.

3-Hydroxypropionic acid (3-HP) is a highly sought-after platform chemical serving as a precursor to a variety of high value-added chemical products. In this study, we designed and constructed a novel light-powered in vitro synthetic enzymatic biosystem comprising acetyl-CoA ligase, acetyl-CoA carboxylase, malonyl-CoA reductase, and phosphotransferase to efficiently produce 3-HP through CO2 fixation from acetate, a cost-effective and readily available substrate. The system employed natural thylakoid membranes (TMs) for the regeneration of adenosine triphosphate and nicotinamide adenine dinucleotide phosphate. Comprehensive investigations were conducted on the effects of buffer solutions, substrate concentrations, enzyme loading levels, and TMs loading levels to optimize the yield of 3-HP. Following optimization, a production of 0.46 mM 3-HP was achieved within 6 h from an initial 0.5 mM acetate, with a yield nearing 92%. This work underscores the simplicity of 3-HP production via an in vitro biomanufacturing platform and highlights the potential for incorporating TMs as a sustainable and environmentally friendly approach in biomanufacturing processes.

Nutrient enrichment and herbivory alter carbon balance in temperate seagrass communities

Large nutrient levels and herbivory stress, particularly when acting together, drive a variety of responses in seagrass communities that ultimately may weaken their carbon balance. An in situ three-months experiment was carried out in two contrasting seasons to address the effects of two levels of nutrient load and three levels of artificial clipping on Cymodocea nodosa plants. Nutrient enrichment shifted the community from autotrophic to heterotrophic and reduced DOC fluxes in winter, whereas enhanced community carbon metabolism and DOC fluxes in summer. Herbivory stress decreased the net primary production in both seasons, whereas net DOC release increased in winter but decreased in summer. A reduction of seagrass food-web structure was observed under both disturbances evidencing impacts on the seagrass ecosystems services by altering the carbon transfer process and the loss of superficial OC, which may finally weaken the blue carbon storage capacity of these communities.

Crack propagation process and lifetime prediction method of concrete-rock interface under constant loading

This study investigated the crack propagation processes and established the lifetime prediction methods of the concrete-rock interfaces under constant loading. Firstly, the constant loading tests were performed under three-point bending loading on the composite concrete-rock beams with three kinds of interfaces, i.e. natural, 4 × 4, and 7 × 7 interfaces, and under three constant load levels, i.e. initial cracking load, 80% and 97% of the peak loads. Then, the clip gauge method and digital image correlation method were employed to detect the crack lengths under constant loading. Finally, the effects of constant load levels on fracture properties of the concrete-rock interfaces were analyzed and the crack propagation processes under constant loading were discussed. The results indicated that the clip gauge method was an available and accurate method to detect the crack lengths of the concrete-rock interfaces under constant loading. Crack propagation processes and crack mouth opening processes under constant loading exhibited the three-stage feature, i.e. deceleration stage, uniform stage and acceleration stage. In addition, the logarithms of the constant loading lifetimes showed an approximate linear relationship with the logarithms of the crack mouth uniform opening rates, and a quantitative relationship was established by using the linear regression analysis to establish the lifetime prediction methods. This study proposed a practical method to predict the service life of concrete structure-bedrock interface. When the crack mouth uniform opening stage was recognized, the lifetime of concrete structure-bedrock interface in service can be predicted by substituting the crack mouth uniform opening rate into the pre-established prediction model. This study can provide the theoretical support for the safety assessment of the concrete structure-bedrock interface in service.

Influence of Montmorillonite Organoclay Fillers on Hygrothermal Response of Pultruded E-Glass/Vinylester Composites

Pultruded fiber reinforced polymer composites used in civil, power, and offshore/marine applications use fillers as resin extenders and for process efficiency. Although the primary use of fillers is in the form of an extender and processing aid, the appropriate selection of filler can result in enhancing mechanical performance characteristics, durability, and multifunctionality. This is of special interest in structural and high voltage applications where the previous use of specific fillers has been at levels that are too low to provide these enhancements. This study investigates the use of montmorillonite organoclay fillers of three different particle sizes as substitutes for conventional CaCO3 fillers with the intent of enhancing mechanical performance and hygrothermal durability. The study investigates moisture uptake and kinetics and reveals that uptake is well described by a two-stage process that incorporates both a diffusion dominated initial phase and a second slower phase representing relaxation and deterioration. The incorporation of the organoclay particles substantially decreases uptake levels in comparison to the use of CaCO3 fillers while also enhancing stage I, diffusion, dominated stability, with the use of the 1.5 mm organoclay fillers showing as much as a 41.5% reduction in peak uptake as compared to the CaCO3 fillers at the same 20% loading level (by weight of resin). The mechanical performance was characterized using tension, flexure, and short beam shear tests. The organoclay fillers showed a significant improvement in each, albeit with differences due to particle size. Overall, the best performance after exposure to four different temperatures of immersion in deionized water was shown by the 4.8 mm organoclay filler-based E-glass/vinylester composite system, which was the only one to have less than a 50% deterioration over all characteristics after immersion for a year in deionized water at the highest temperature investigated (70 °C). The fillers not only enhance resistance to uptake but also increase tortuosity in the path, thereby decreasing the overall effect of uptake. The observations demonstrate that the use of the exfoliated organoclay particles with intercalation, which have been previously used in very low amounts, and which are known to be beneficial in relation to enhanced thermal stability, flame retardancy, and decreased flammability, provide enhanced mechanical characteristics, decreased moisture uptake, and increased hygrothermal durability when used at particle loading levels comparable to those of conventional fillers, suggesting that these novel systems could be considered for critical structural applications.

The characteristics of WM in individuals with depressive tendencies: A functional near-infrared spectroscopy (fNIRS) study

Individuals with depressive tendencies are considered to be at high risk for the onset of depressive disorders. Currently, most research focuses on the impairment of working memory in patients with depression, while there is less attention paid to the WM of individuals with depressive tendencies, and their neural mechanisms underlying it are poorly understood. Therefore, this study focuses on the characteristics and neural mechanisms of WM in individuals with depressive tendencies. This study uses functional near-infrared spectroscopy (fNIRS) to monitor the concentration of Oxy-Hb in the prefrontal cortex and employs the n-back paradigm, designing three levels of load: 0, 1, and 2, to examine the characteristics of WM and its neural mechanisms in individuals with depressive tendencies. Behavioral results show that the accuracy rates of individuals with depressive tendencies is significantly lower than that of healthy individuals, and under the 0-back condition, the reaction time of individuals with depressive tendencies is significantly higher than that of healthy control individuals. Near-infrared results indicate that the activation level in the frontal pole and the dorsal lateral prefrontal cortex of individuals with depressive tendencies is significantly lower than that of healthy control individuals. The β values of channels 2, 7, and 9 are significantly negatively correlated with the Beck Depression Inventory scores of the participants. The results suggest that the reduced activation of the frontal pole and dorsal lateral prefrontal cortex in individuals with depressive tendencies leads to poorer WM performance compared to healthy control individuals. This is a rare brain evidence of the characteristics of WM in individuals with depressive tendencies, which can provide a deeper understanding of the WM characteristics of individuals with depressive tendencies.

A multiaxial thermo-mechanical damage model for concrete including Load Induced Thermal Strain (LITS)

In the current study, a multiaxial LITS model of concrete was innovatively developed. This model can predict the behavior of concrete subjected to wide applied load level ranges from 20 % to 80 % and temperatures up to 800 °C. A 3D LITS model is developed through a triaxial compression stress confinement implementation and Poisson's ratio. Considering the water evaporation of concrete under high temperature, a third order polynomial LITS derivative function and an exponential derivative function were proposed to characterize the effects of the stress confinement and thermal effect. In order to comprehensively predict the performance of concrete subjected to multiaxial compressive loads in fire, an orthotropic triaxial compression thermo-mechanical damage model for concrete is developed. The effect of LITS on the multiaxial stress-strain response was considered in the multiaxial model. The coupling thermo-mechanical contributions containing the development of LITS among thermal effect, stress confinement, damage and plastic hardening evolution were creatively considered in the potential function within thermodynamics framework. The numerical calculations of this proposed model were conducted for validation. The effect of LITS on the multiaxial stress-strain response was studied. The nonlinear stress-strain responses of concrete were accurately captured at temperatures ranges from 20 °C to 1000 °C through the comparative study with test results in literatures, which indicates the accuracy and applicability of the proposed model.

Experimental investigation on Nano-Al2O3 and hydroxypropyl methyl cellulose (HPMC) modified cement-based coatings for corrosion resistance

In this work, cementitious coatings doped with nano-Al2O3 (NA) and hydroxypropyl methyl cellulose (HPMC) were prepared in order to enhance corrosion resistance of steel bar. The electro-chemical behaviors and corrosion inhibition properties of coated steel bar and tensioned coated steel bars (subjected to 10 %, 30 % and 50 % yield load) were analyzed in 3.5 wt% NaCl solution for 840 h (35 days). At the end of electrochemical test, coating overall performance was evaluated by visual inspection. In addition, scanning electron microscopy (SEM), transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS) were used to examine microstructure and elemental composition of coatings. To comprehend the anti-corrosion mechanism of the coatings, X-ray diffraction (XRD) and infrared spectroscopy (FTIR) analysis to characterize products composition and chemical groups. Test results obtained by linear polarization resistance and electrochemical impedance spectroscopy indicated that both tensile and non-tensile coatings resistance show an increasing trend followed by a decrease with increasing NA content. Cementitious coatings incorporating 1 % NA and 0.12 % HPMC by weight of cement exhibited the best corrosion protection. The LPR fluctuates around 3700 Ω cm2, which is about twice as much as a single doped NA coating. Whether subjected to tensile loads or not, OCP values for all coated steel bar were below −0.273 V/SCE, indicating has a 90 % probability of being in active-corrosion. The corrosion resistance of tensioned coated bars decreased as time and increased load level. According to SEM and TEM image, HPMC forms a thin and continuous film on the substrate surface, which acts as a barrier to the penetration of moisture and corrosive agents. Coatings doped with 1 % NA and 0.12 % HPMC formed denser integrated polymer films at the microscopic. FTIR and XRD results showed that coating incorporated NA consumed the cement hydration product Ca(OH)2 to generate more nanofibers filling pores and microcracks. Coatings incorporating HPMC show better resistance to carbonization.

Comparation of non-proportional hardening behavior and microscopic mechanism for CP-Ti under strain-controlled and stress-controlled multiaxial low cycle fatigue

Proportional and non-proportional multiaxial low cycle fatigue tests were performed on commercial pure titanium (CP-Ti), employing both strain-controlled and stress-controlled modes. CP-Ti exhibits a four-stage characteristic under higher applied strain amplitude. For other cases and under stress-controlled mode, the initial hardening dissipated, giving way to a typical three-stage cyclic softening characteristics. Two failure modes, fatigue failure and ratcheting failure, occur depending on the applied stress amplitude. CP-Ti exhibits obvious asymmetric strain response under symmetric stress-controlled mode depending on the loading level. CP-Ti demonstrates non-proportional hardening under both strain-controlled mode and stress-controlled mode with different microscopic mechanisms. The additional hardening due to non-proportional loading results in an increase in the axial response stress with increasing multiaxial strain ratio. Interactions between dislocations with different slip systems hinder the development of stable dislocation structures, leading to pronounced non-proportional hardening of CP-Ti under strain-controlled mode. As for stress-controlled mode, the significant growth of twin content improves the grain boundary strength, leading to the non-proportional hardening of CP-Ti.

Effect of sequential tasks in the case studies of business English textbooks on fostering critical thinking based on cognitive load theory

There is a consensus that case studies in Business English class are helpful to foster critical thinking, but little research has been done to explore how case studies facilitate it. To bridge the gap, the present study uses the revised Bloom’s taxonomy as a tool to qualitatively and quantitatively investigate the effect of case studies in Market Leader textbooks on fostering critical thinking based on cognitive load theory. First, the presence of six cognitive levels targeted in the tasks is examined to see how case studies sequence their tasks according to the increase of cognitive complexity. Secondly, the scaffoldings distributed across the sequential tasks are explored to investigate how well they impose appropriate amount of cognitive load on students. Although six cognitive levels are found, there is an inappropriate administration of task scaffolding in a single task or task chain, leading to insufficient or superficial scaffolds and thus inducing high level of cognitive load for students to develop critical thinking. Accordingly, case study writers and teachers are recommended, when designing and adapting sequential tasks, to consider systematic inculcation of cognitive levels among tasks and proper administration of scaffolding with regard to the aspects of task input, conditions, progress and outcome so that a balanced level of cognitive load aligned with the state of working memory capacity of students can be achieved for fostering critical thinking.

Utilization of waste tire derived activated carbon as CO2 capture and photocatalyst for CO2 conversion

The aims of this research were to prepare activated carbon (AC) impregnated with tetraethylenepentamine (TEPA) for use in carbon dioxide (CO2) capture and to then develop the AC-TEPA sorbent with titanium dioxide (TiO2) as a catalyst for photocatalytic reduction. The AC was impregnated with TEPA at three loading levels (2.5, 5, and 10% [w/w]) and then examined for its CO2 adsorption capacity under an ambient temperature and atmospheric pressure. The use of 5% (w/w) TEPA-impregnated AC (AC_5T) provided the highest CO2 adsorption capacity and long-term operation with a regeneration ability for up to 10 cycles. Then, AC_5T-doped TiO2 (AC_5T-TiO2) was prepared as a photocatalytic reduction catalyst, since the presence of carbon and nitrogen in AC_5T could reduce the band gap energy and so enhance the photocatalytic reduction. In addition, the CO2-saturated AC_5T was used as a CO2 source that could be directly converted to valuable chemicals using the AC_5T-TiO2 catalyst under photocatalytic reduction. Products were obtained in both the liquid (methanol) and gaseous (methane, carbon monoxide, and hydrogen) phases. Accordingly, the challenge of this research was to make valuable products from CO2 and to manage waste tires, following the circular economy concept.

Planning a Hybrid Battery Energy Storage System for Supplying Electric Vehicle Charging Station Microgrids

This paper presents a capacity planning framework for a microgrid based on renewable energy sources and supported by a hybrid battery energy storage system which is composed of three different battery types, including lithium-ion (Li-ion), lead acid (LA), and second-life Li-ion batteries for supplying electric vehicle (EV) charging stations. The objective of this framework is to determine the optimal size for the wind generation systems, PV generation systems, and hybrid battery energy storage systems (HBESS) with the least cost. The framework is formulated as a mixed integer linear programming (MILP) problem, which incorporates constraints for battery ageing and the amount of unmet load for each year. The system uncertainties are managed by conducting the studies for various scenarios, generated and reduced by generative adversarial networks (GAN) and the k-means clustering algorithm for wind speed, global horizontal irradiation, and EV charging load. The studies are conducted for three levels of unmet load, and the outputs are compared for these reliability levels. The results indicate that the cost of hybrid energy storage is lower than individual battery technologies (21% compared to Li-ion, 4.6% compared to LA, and 6% compared to second-life Li-ion batteries). Additionally, by using HBESS, the capacity fade of LA batteries is decreased (for the unmet load levels of 0, 1%, 5%, 4.2%, 6.1%, and 9.7%, respectively), and the replacement of the system is deferred proportional to the degradation reduction.

The High Burden of Asymptomatic Kidney Diseases in Individuals with HIV: A Prospective Study from a Tertiary Care Center in India

Background HIV infection is associated with a significant kidney disease burden. This study is aimed to screen for kidney disease in all HIV patients on highly active anti retroviral therapy (HAART), study clinico-histological correlation, and assess the impact of early diagnosis on the clinical course. Materials and Methods It was a prospective, longitudinal study done in a tertiary care hospital. Adult HIV-infected patients, on HAART for at least 3 months, were screened for kidney disease. Kidney biopsy was done if indicated. Patients were treated as per standard guidelines. Results were analyzed at 3 months. Results Among 1600 patients, 966 were compliant with HAART and were tested. Two hundred and sixty-two patients completed the study duration. Out of these 262 patients 78.2% were receiving tenofovir-based ART regimen. Around 31.2% were hypertensive and 19.8% were diabetic. The mean eGFR was 57.5 ± 24 mL/min/1.73 m2. Around 19.8% had asymptomatic urine abnormalities, 40.1% had proteinuria, and 27.1% had AKI. Acute nephritic syndrome was seen in 16.4%, rapidly progressive renal failure (RPRF) in 13.3%, and CKD in 10.6% patients. Out of 74 patients who underwent biopsy, histology showed chronic tubulointerstitial nephritis in 16 (21.6%), acute tubulointerstitial nephritis in 11 (14.8%), diabetic nephropathy in 10 (13.5%), and thrombotic microangiopathy in 7 patients (9.4%). Higher viral load levels, diabetes mellitus, and age above 60 years were associated with kidney disease. Conclusion Asymptomatic HIV infection has a significant burden of kidney disease. Kidney biopsy is crucial for correct diagnosis and management. The absence of HIV associated nephropathy in proteinuric HIV patients is notable in this study.

Hydrogen combustion analysis via infrared and visible optical diagnostics combined with CFD in a dual fuel engine at low load

Dual Fuel (DF) combustion concept has demonstrated to be a valid solution to ensure the utilization of diesel engines in heavy duty and naval applications. The substitution of part of diesel fuel with a cleaner gaseous one can reduce among others: carbon dioxides (CO2), nitrogen oxides (NOx) and surely particulate matter (PM). Nevertheless, the difficulties encountered by the reduced pilot liquid jet to reach out the furthest areas of the combustion chamber, especially at partial load, lead to unburned emissions of the premixed charge. They can be a serious issue to overcome when the premixed fuel is represented by a carbonaceous fuel like natural gas (NG). For this reason, hydrogen, that is carbon-free, represents the new progression to clean mobility. This work aims at deepening the in-cylinder phenomena through a synergetic methodology that involves experimental optical diagnostics and 3D numerical investigations. The experimental activity is carried out on a single cylinder research engine (SCRE) equipped with an optical apparatus allowing the visualization of the combustion process, later processed via high speed visible (VIS) and infrared (IR) imaging. Several filters applied on the IR camera permit to detect specific species such as CO2. Subsequently, these outcomes are used to validate numerical models, and in turn, the numerical results help to validate the species detected qualitatively via optical diagnostics and to identify which ones majorly affect the physical and chemical processes. Numerical simulations are performed with ANSYS Forte ® code on a geometry which accurately reproduces the shape of the combustion chamber. Combustion models include a turbulent-kinetic interaction model with a mechanism of 124 species and 660 reactions to deal with the autoignition phase and diesel surrogate oxidation, while to account for the flame propagation through the premixed charge the G-equation is considered. The reference test cases are characterized by two different engine speeds, 1500 and 2000 rpm, and a low load level, corresponding to 2 bar of brake mean effective pressure (BMEP) on light-duty vehicle. The hydrogen energy shares are between 83.2 and 81.8%. Results demonstrate that IR images and OH radical are key for the detection of ignition process of both diesel and hydrogen. The flame propagation in the air/H2 charge can be observed with the help of CFD elaborations. Finally, emission levels are adequately predicted by the chosen oxidation models.

MATB for assessing different mental workload levels

Multi-Attribute Task Battery (MATB) is a computerized flight simulator for aviation-related tasks, suitable for non-pilots and available in many versions, including open source. MATB requires the individual or simultaneous execution of 4 sub-tasks: system monitoring (SYSMON), tracking (TRACK), communications (COMM), and resource management (RESMAN). Fully customizable, the design of test duration, number of sub-tasks used, event rates, response times and overlap, create different levels of mental load. MATB can be combined with an additional auditory attention (Oddball) task, or with physiological constraints (i.e., sleep loss, exercise, hypoxia). We aimed to assess the main characteristics of MATB design for assessing the response to different workload levels. We identified and reviewed 19 articles for which the effects of low and high workload were analyzed. Although MATB has shown promise in detecting performance degradation due to increase workload, studies have yielded conflicting or unclear results regarding MATB configurations. Increased event rates, number of sub-tasks (multitasking), and overlap are associated with increased perceived workload score (ex. NASA-TLX), decreased performance (especially tracking), and neurophysiological responses, while no effect of time-on-task is observed. The median duration used for the test is 20 min (range 12–60) with a level duration of 10 min (range 4–15). To assess mental workload, the median number of stimuli is respectively 3 events/min (range 0.6–17.2) for low, and 23.5 events/min (range 9–65) for high workload level. In this review, we give some recommendations for standardization of MATB design, configuration, description and training, in order to improve reproducibility and comparison between studies, a challenge for the future researches, as human-machine interaction and digital influx increase for pilots. We also open the discussion on the possible use of MATB in the context of aeronautical/operational constraints in order to assess the effects combined with changes in mental workload levels. Thus, with appropriate levels of difficulty, MATB can be used as a suitable simulation tool to study the effects of changes on the mental workload of aircraft pilots, during different operational and physiological constraints.

Enzymatic Modulation of the Pulmonary Glycocalyx Enhances Susceptibility to Streptococcus pneumoniae.

The pulmonary epithelial glycocalyx is rich in glycosaminoglycans such as hyaluronan and heparan sulfate. Despite their presence, the importance of these glycosaminoglycans in bacterial lung infections remains elusive. To address this, we intranasally inoculated mice with Streptococcus pneumoniae in the presence or absence of enzymes targeting pulmonary hyaluronan and heparan sulfate, followed by characterization of subsequent disease pathology, pulmonary inflammation, and lung barrier dysfunction. Enzymatic degradation of hyaluronan and heparan sulfate exacerbated pneumonia in mice, as evidenced by increased disease scores and alveolar neutrophil recruitment. However, targeting epithelial hyaluronan in combination with Streptococcus pneumoniae infection further exacerbated systemic disease, indicated by elevated splenic bacterial load and plasma levels of pro-inflammatory cytokines. In contrast, enzymatic cleavage of heparan sulfate resulted in increased bronchoalveolar bacterial burden, lung damage and pulmonary inflammation in mice infected with Streptococcus pneumoniae. Accordingly, heparinase-treated mice also exhibited disrupted lung barrier integrity as evidenced by higher alveolar edema scores and vascular protein leakage into the airways. This finding was corroborated in a human alveolus-on-a-chip platform, confirming that heparinase treatment also disrupts the human lung barrier during Streptococcus pneumoniae infection. Notably, enzymatic pre-treatment with either hyaluronidase or heparinase also rendered human epithelial cells more sensitive to pneumococcal-induced barrier disruption, as determined by transepithelial electrical resistance measurements, consistent with our findings in murine pneumonia. Taken together, these findings demonstrate the importance of intact hyaluronan and heparan sulfate in limiting pneumococci-induced damage, pulmonary inflammation, and epithelial barrier function and integrity.

Innate lymphoid cells are activated in HFRS, and their function can be modulated by hantavirus-induced type I interferons.

Hantaviruses cause the acute zoonotic diseases hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Infected patients show strong systemic inflammation and immune cell activation. NK cells are highly activated in HFRS, suggesting that also other innate lymphoid cells (ILCs) might be responding to infection. Here, we characterized peripheral ILC responses, and measured plasma levels of soluble factors and plasma viral load, in 17 Puumala virus (PUUV)-infected HFRS patients. This revealed an increased frequency of ILC2 in patients, in particular the ILC2 lineage-committed c-Kitlo ILC2 subset. Patients' ILCs showed an activated profile with increased proliferation and displayed altered expression of several homing markers. How ILCs are activated during viral infection is largely unknown. When analyzing PUUV-mediated activation of ILCs in vitro we observed that this was dependent on type I interferons, suggesting a role for type I interferons-produced in response to virus infection-in the activation of ILCs. Further, stimulation of naïve ILC2s with IFN-β affected ILC2 cytokine responses in vitro, causing decreased IL-5 and IL-13, and increased IL-10, CXCL10, and GM-CSF secretion. These results show that ILCs are activated in HFRS patients and suggest that the classical antiviral type I IFNs are involved in shaping ILC functions.

Analysis of performance improvement methods for offshore wind turbine blades affected by leading edge erosion

Leading edge erosion (LEE) poses greater challenges to the blade design of offshore wind turbines. This paper analyzes the influence of LEE on blade aerodynamic performance and wind turbine load based on high-power offshore wind turbines through the GH-Bladed computing platform. The study found that LEE severely weakens the blade aerodynamic performance, resulting in a lag in the wind turbine reaching its rated power. LEE expands the range of blade surface flow separation, leading to an increase in blade stall risk and a decrease in wind turbine load stability. The promotion of blade aerodynamic performance will cause an increase in blade force, which will strengthen the load level of both the blade and the wind turbine. The optimization of twist angle is an effective method to avoid the loss of power generation of wind turbines under LEE interference, but it is inevitable to cause a decrease in the load stability of wind turbines. Therefore, when the load safety margin of wind turbines is sufficient, adjusting the twist angle is an efficient technique to improve the blade aerodynamic performance and promote the stability of power output, which provides a novel solution for blade design of high-power offshore wind turbines.

Modulation of alpha oscillations by attention is predicted by hemispheric asymmetry of subcortical regions.

Evidence suggests that subcortical structures play a role in high-level cognitive functions such as the allocation of spatial attention. While there is abundant evidence in humans for posterior alpha band oscillations being modulated by spatial attention, little is known about how subcortical regions contribute to these oscillatory modulations, particularly under varying conditions of cognitive challenge. In this study, we combined MEG and structural MRI data to investigate the role of subcortical structures in controlling the allocation of attentional resources by employing a cued spatial attention paradigm with varying levels of perceptual load. We asked whether hemispheric lateralization of volumetric measures of the thalamus and basal ganglia predicted the hemispheric modulation of alpha-band power. Lateral asymmetry of the globus pallidus, caudate nucleus, and thalamus predicted attention-related modulations of posterior alpha oscillations. When the perceptual load was applied to the target and the distractor was salient caudate nucleus asymmetry predicted alpha-band modulations. Globus pallidus was predictive of alpha-band modulations when either the target had a high load, or the distractor was salient, but not both. Finally, the asymmetry of the thalamus predicted alpha band modulation when neither component of the task was perceptually demanding. In addition to delivering new insight into the subcortical circuity controlling alpha oscillations with spatial attention, our finding might also have clinical applications. We provide a framework that could be followed for detecting how structural changes in subcortical regions that are associated with neurological disorders can be reflected in the modulation of oscillatory brain activity.

Modulation of alpha oscillations by attention is predicted by hemispheric asymmetry of subcortical regions

Evidence suggests that subcortical structures play a role in high-level cognitive functions such as the allocation of spatial attention. While there is abundant evidence in humans for posterior alpha band oscillations being modulated by spatial attention, little is known about how subcortical regions contribute to these oscillatory modulations, particularly under varying conditions of cognitive challenge. In this study, we combined MEG and structural MRI data to investigate the role of subcortical structures in controlling the allocation of attentional resources by employing a cued spatial attention paradigm with varying levels of perceptual load. We asked whether hemispheric lateralization of volumetric measures of the thalamus and basal ganglia predicted the hemispheric modulation of alpha-band power. Lateral asymmetry of the globus pallidus, caudate nucleus, and thalamus predicted attention-related modulations of posterior alpha oscillations. When the perceptual load was applied to the target and the distractor was salient caudate nucleus asymmetry predicted alpha-band modulations. Globus pallidus was predictive of alpha-band modulations when either the target had a high load, or the distractor was salient, but not both. Finally, the asymmetry of the thalamus predicted alpha band modulation when neither component of the task was perceptually demanding. In addition to delivering new insight into the subcortical circuity controlling alpha oscillations with spatial attention, our finding might also have clinical applications. We provide a framework that could be followed for detecting how structural changes in subcortical regions that are associated with neurological disorders can be reflected in the modulation of oscillatory brain activity.

Learning with videos: Do task instructions and the availability of a pause button matter?

AbstractBackgroundWhen watching educational online videos, learners need to determine whether the videos' contents are suitable for learning. Whereas this may induce metacognitive monitoring processes, it may also distract learners from the learning materials.ObjectivesIn the current set of experiments, we investigated whether asking participants to rate the suitability of three educational videos to impart knowledge (both experiments) and enabling participants to pause the video (Experiment 2) affects learning.MethodsExperiment 1 was conducted in the laboratory with a sample of university students. Participants were randomly assigned to one of two experimental conditions (rating task vs. viewing task). Experiment 2 was conducted online. Participants were randomly assigned to one of four conditions resulting from the two factors task (rating task vs. viewing task) and pause button (available vs. not available).Results and ConclusionIn Experiment 1, we observed detrimental effects of the rating task on learning outcomes, but more accurate judgements of learning. In Experiment 2, we did not find any effects of the rating task on learning outcomes and the accuracy of the participants' judgements of learning. However, the inclusion of a pause button did result in more accurate judgements of learning. Further, exploratory analyses revealed that older participants reported higher levels of intrinsic and germane cognitive load than the younger participants. This increased effort only translated into better learning outcomes in the condition in that participants could pause the video. Thus, age is introduced as a potential boundary condition that should be investigated in instructional design research.