Time Interaction Research Articles

BLUNTED SKELETAL MUSCLE MICROVASCULAR BLOOD FLOW IS A POTENTIAL UNDERLYING MECHANISM FOR EXERCISE INTOLERANCE IN ADULTS WITH ATRIAL FIBRILLATION

INTRODUCTION & AIMS Approximately 45% of adults living with atrial fibrillation (AF) experience exercise intolerance (EI). However, the mechanisms of EI in AF are not well understood. We aimed to determine whether impaired skeletal muscle microvascular blood flow (MBF), not macrovascular, responses to peak exercise is a plausible explanation for EI in adults with AF. METHODS Adults with AF and healthy controls completed a Modified Bruce treadmill protocol to obtain peak oxygen uptake (V̇O2peak). Skeletal muscle microvascular blood volume, velocity, and flow in the vastus lateralis muscle was assessed using contrast enhanced ultrasound. Superficial femoral artery diameter, blood velocity and flow were assessed using 2D and Doppler ultrasound. Vascular measurements were collected at rest, immediately post-exercise, and 30 minutes post-exercise. RESULTS Nine adults with AF (age: 62±5 years, 66% females, BMI: 29.7±4.2 kg/m2, V̇O2peak: 24.3±6.1 mL/kg/min) and seven controls (age: 63±10 years, 57% females, BMI: 26.7±1.7 kg/m2, V̇O2peak: 31.0±7.5 mL/kg/min) participated. One participant was in AF during testing. A significant group x time interaction in skeletal muscle MBF (p=0.04) and near significant interaction in blood volume (capillary recruitment, p=0.08) was observed. Post-hoc analysis revealed adults with AF had a significantly blunted MBF at 30 minutes post-exercise (-1.3 fold versus control, p=0.01) and reduced microvascular blood volume (i.e. capillary recruitment) pre- and 30 minutes post-exercise (-6.6 fold [p=0.01] and -9.4 fold [p=0.01] versus controls). No differences were observed for changes in skeletal muscle microvascular blood velocity, or femoral artery diameter, blood velocity or flow. CONCLUSION Despite similar femoral artery blood flow responses, adults with AF have lower skeletal muscle MBF responses to peak exercise which may be driven by a reduced capillary recruitment in the skeletal muscle. Our findings provide new insight into vascular complications which may partially explain EI in those with AF.

Arterial stiffness and wave reflection responses to acute and chronic high intensity interval training in healthy older adults

Aging leads to large elastic artery stiffness which is associated with early return of wave reflection. These age-related alterations increase left ventricular afterload, predisposing older adults to cardiovascular disease. Endurance training is an effective strategy to reduce cardiovascular disease risk. We have developed a supervised home-based exercise intervention using high intensity interval training on an all-extremity non-weight-bearing ergometer (HIIT-ANE). This study aimed to test the following hypotheses in healthy older adults: 1) arterial stiffness and wave reflection would decrease in response to chronic HIIT-ANE, 2) arterial stiffness and wave reflection responses to acute HIIT-ANE would differ in the untrained compared to the trained states, and 3) arterial stiffness and aortic wave reflection responses to acute and chronic HIIT-ANE would be related. Twenty older adults (66±1 years, mean ± SE; 11 postmenopausal women and 9 men) participated in this study. Carotid-femoral pulse wave velocity (cfPWV) and augmentation index at heart rate 75 bpm (AIx@75)—indices of arterial stiffness and wave reflection, respectively—were assessed by SphygmoCor XCEL at baseline (T0), following 8 weeks of normal lifestyle (T1; control condition), and following 8 weeks of supervised home-based HIIT-ANE (T2). Acute cfPWV and AIx@75 responses to HIIT-ANE were assessed at pre-, end-of-, 1-hr post- and 24-hrs post-exercise, in the untrained and trained states. cfPWV increased after 8 weeks of normal lifestyle (T0 vs. T1: 7.9±0.3 vs. 8.2±0.3 m/s, P=0.03), but it decreased following 8 weeks of HIIT-ANE (T1 vs. T2: 8.2±0.3 vs. 7.7±0.3 m/s, P<0.001). AIx@75 decreased after 8 weeks of HIIT-ANE compared to baseline and following 8 weeks of normal lifestyle (T0 vs. T2: 23.7±1.8 vs. 17.8±1.9 %, P<0.001; T1 vs. T2: 24.9±2.2 vs. 17.8±1.9 %, P<0.001). Acute cfPWV and AIx@75 responses to HIIT-ANE were similar in the untrained and trained states ( P for condition×time interaction; cfPWV: P=0.8; AIx@75: P=0.9). cfPWV and AIx@75 responses to chronic HIIT-ANE were not significantly related with acute responses to HIIT-ANE in the untrained (cfPWV: r=0.07, P=0.8; AIx@75: r=-0.32, P=0.2) and trained states (cfPWV: r=0.10, P=0.7; AIx@75: r=-0.32, P=0.2). In conclusion, we have demonstrated that supervised home-based HIIT-ANE has beneficial vascular effects in healthy older adults. We also showed that acute vascular responses to HIIT-ANE do not change from the untrained to trained state and are not predictive of chronic vascular responses to HIIT-ANE. This work was supported by the National Institute of Aging grant AG063143. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Longitudinal Assessment of Outcome Measures of Diaphragm Motor Unit Connectivity As Biomarkers of Phrenic Motor Unit Degeneration and Compensation

Phrenic motor neurons (MNs) form the final link from the central nervous system (CNS) to the diaphragm muscle. Ventilatory function is modulated by the CNS via groups of muscle fibers each controlled by a single MN (motor units). Processes such as injury, aging, and neurodegeneration can result in losses of MNs, and their motor unit (MU) counterparts, but MNs and MUs have some capacity for compensation through mechanisms such as axonal sprouting and collateral sprouting to regain connectivity with denervated muscle. Motor unit number (motor unit number estimation, MUNE), MU size (single motor unit potential amplitude, SMUP), and summated muscle excitation (compound muscle action potential amplitude, CMAP) have been used clinically and preclinically for decades to track MU connectivity but efforts have largely focused on limb muscles. We aimed to apply these measures to a model of phrenic MN degeneration (intrapleural injection of cholera toxin B fragment conjugated to saporin, CTB-SAP).We hypothesized that CTB-SAP-induced phrenic motor neuron death would result in loss of diaphragm MU number and compensatory increases in MU size. Under isoflurane anesthesia, rats were bilaterally, intrapleurally injected with CTB-SAP (25 μg) to target phrenic MNs and extra CTB (25 μg) to label surviving phrenic MNs, and control rats received unconjugated CTB (25 μg) and SAP (25 μg). Diaphragm CMAP, SMUP, and MUNE were acquired bilaterally and averaged at baseline/pre-injection (n=14), as well as 7 (n=14), 14 (n=14), 21 (n=6), and 28 (n=14) days post-injection. No baseline differences between groups were found. MUNE showed a significant change for time (p<0.05), treatment (p<0.001), and interaction time x treatment (p<0.01) with ~40% reduction of MUNE in CTB-SAP rats. Average SMUP of CTB-SAP rats demonstrated a significant change with time (p<0.05) and treatment (p<0.01), but no significant interaction with ~50-60% increase in SMUP amplitude. CMAP showed no significant change. Our results show a significant ~40% loss of MUs in CTB-SAP rats, similar to previous studies on morphological MN counts. In parallel with MU loss, MUs enlarged (increased SMUP), consistent with compensatory increases of MU size likely through MU collateral sprouting. In conclusion, our findings suggest that the use of diaphragm MU electrophysiological measures can provide insights into the onset and progression of CTB-SAP-induced pathology concerning the loss of phrenic MU integrity. Hence, these biomarkers can be used to investigate mechanisms of phrenic motor neuron degeneration and compensation, and to expedite the translation of experimental findings to clinical testing. Supported by a Spinal Cord Injury and Disease Research grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of physical activity education on shoulder girdle pain and muscle strength in participants with fibromyalgia: a pilot experimental study.

In patients with fibromyalgia, exercise and education are recommended to decrease pain level and improve pain management. The latest scientific evidence recommends to focus interventions on the upper limb. The aim of this pilot study was to compare the immediate effect of physical activity education vs. a control group on pain and muscle capacity in fibromyalgia patients. Fifty-six participants with fibromyalgia were randomized into an experimental group and a control group. The intervention consisted in watching a five-minute video that provided information about fibromyalgia, pain, kinesiophobia and physical activity. The control group watched a neutral five-minute video about beavers in Quebec. Following the video, participants performed a muscular fatigue task consisting of a repeated unilateral shoulder abduction task. At baseline and following the muscular fatigue task, maximal voluntary contraction (MVC) in shoulder abduction was assessed as well as pain level and pressure pain threshold (PPT) in the upper limb. Electromyographic activity was also assessed for upper trapezius and middle deltoid muscles. Two-way repeated measures analysis of variance was used to compare the MVC, PPT, and pain level before and after the muscular fatigue task between groups. The experimental group showed a significantly lower increase in pain than the control group in the middle deltoid muscle (p = 0.002) when assessed by verbal pain rating scale. No significant interaction or main effect of Group and Time were observed for the pain level at the upper trapezius and elbow extensor muscles nor for any of the PPT measures. According to electromyographic data, the median frequency values indicate that neither group experienced muscle fatigue during the repeated contraction task. The preliminary results suggest that a short physical activity education video positively influenced middle deltoid pain following repeated abduction in participants with fibromyalgia. Electromyographic analysis showed no evidence of objective muscle fatigue, suggesting that there might be a partial disconnection between the perception of muscle fatigue and the physiological biomarkers associated with muscle fatigue.

Mindfulness-Based Stress Reduction and Autonomic Modulation in Chronic Kidney Disease

Intro: Chronic kidney disease (CKD) is characterized by chronic overactivation of the sympathetic nervous system (SNS) that leads to increased blood pressure and cardiovascular disease risk. Mindfulness-Based Stress Reduction (MBSR) is an 8-week mindfulness meditation training program that has previously been shown to reduce blood pressure and improve autonomic balance in healthy and some clinical populations; however, MBSR has never previously been tested in CKD and the long-term effects of mindfulness mediation on SNS activity are unknown. Thus, we tested the hypothesis that 8 weeks of MBSR reduces SNS activity and reactivity in CKD patients. Method: In a randomized controlled trial, participants with CKD stages III-IV were randomized to 8 weeks of MBSR (n=17, 64±8 yr, 88% males) or a health education program (HEP, n=12, 63±10 yr, 83% males) that served as the active control intervention. MBSR was comprised of eight 2.5-hour group meetings and a retreat session focused on mindfulness training. HEP was administered in a similar structure and focused on health education. Direct intraneural measures of SNS activity directed to muscle (MSNA) was recorded via microneurography with concomitant beat-to-beat blood pressure and EKG monitoring at rest and during mental stress before and after the 8-week intervention. MSNA reactivity during mental arithmetic-induced stress (3 minutes) was compared between baseline and end of study (EOS) in the MBSR and HEP groups. Results. Baseline characteristics, kidney function, and comorbidities were comparable between groups. There was a significant Group (MBSR vs. HEP) by Time (baseline vs. EOS) interaction in the change in MSNA reactivity to mental stress. The MBSR group had a significant reduction in MSNA reactivity during the 1st, 2nd and 3rd minute of mental arithmetic at EOS (p<0.05 for all), while no change was observed within the HEP group. Resting MSNA and reactivity in blood pressure and heart rate during mental arithmetic remained unchanged in both groups from baseline to EOS. Conclusion. Patients with CKD had an amelioration of sympathetic reactivity during mental stress following 8-weeks of MBSR but not after HEP (control intervention). Our findings demonstrate that mindfulness training is feasible and may have potential beneficial effects on autonomic function in CKD. NIH R01HL135183; NIH R61AT10457; NIH KL2TR002381; VA Merit I01CX001065. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Toward Alleviating Clinician Documentation Burden: A Scoping Review of Burden Reduction Efforts.

Studies have shown that documentation burden experienced by clinicians may lead to less direct patient care, increased errors, and job dissatisfaction. Implementing effective strategies within health care systems to mitigate documentation burden can result in improved clinician satisfaction and more time spent with patients. However, there is a gap in the literature regarding evidence-based interventions to reduce documentation burden. The objective of this review was to identify and comprehensively summarize the state of the science related to documentation burden reduction efforts. Following Joanna Briggs Institute Manual for Evidence Synthesis and Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines, we conducted a comprehensive search of multiple databases, including PubMed, Medline, Embase, CINAHL Complete, Scopus, and Web of Science. Additionally, we searched gray literature and used Google Scholar to ensure a thorough review. Two reviewers independently screened titles and abstracts, followed by full-text review, with a third reviewer resolving any discrepancies. Data extraction was performed and a table of evidence was created. A total of 34 articles were included in the review, published between 2016 and 2022, with a majority focusing on the United States. The efforts described can be categorized into medical scribes, workflow improvements, educational interventions, user-driven approaches, technology-based solutions, combination approaches, and other strategies. The outcomes of these efforts often resulted in improvements in documentation time, workflow efficiency, provider satisfaction, and patient interactions. This scoping review provides a comprehensive summary of health system documentation burden reduction efforts. The positive outcomes reported in the literature emphasize the potential effectiveness of these efforts. However, more research is needed to identify universally applicable best practices, and considerations should be given to the transfer of burden among members of the health care team, quality of education, clinician involvement, and evaluation methods.

Trends in imported infections among migrants and travellers to Spain: a decade of analysis through the +Redivi network (2012-2022).

High-speed global travel, increased trade, world population growth, migration, urbanisation and climate change have favoured the emergence and spread of pathogens. We aimed to analyse the evolution of imported infections in Spain during 2012-2022 and the potential impact of some of the abovementioned factors on differential morbidity patterns. In this retrospective study (January/2012 to December/2022), we analysed data collected by the +Redivi network across 25 health centres. The network's standardised database records new cases of imported infections, including patient demographics, travel history, pre-travel advice and diagnostic information. To assess outcome rates over time and potential interactions, we constructed penalised weighted models to reduce the bias related to a low event rate and used weighted logistic regression for morbidity outcomes. We recorded 25 632 episodes, comprising 13 913 migrants, 4047 visiting friends and relatives (VFR) immigrants, 392 VFR travellers and 7280 travellers. Most immigrants came from South America (48.3%), Sub-Saharan Africa (28.5%), North Africa (6.6%), South Central Asia (5.4%) and Central America/Caribbean (5.3%). The most common regions visited by travellers were Sub-Saharan Africa (33.5%), South America (24.5%), Central America/Caribbean (13.5%), Southeast Asia (12%) and South Central Asia (10%). The proportion of diagnoses of malaria, strongyloidiasis and unspecified self-limiting febrile syndrome < 3weeks remained unchanged during the study period. An increased frequency of diagnosis was reported for schistosomiasis, blastocystosis, giardiasis, dengue, diarrhoea, new cases of HIV, latent and pulmonary tuberculosis; a decrease was reported for syphilis, chikungunya fever, Chagas disease and eosinophilia. We detected interactions between time and sex or type of participant across the different diagnoses. Our study underscores the importance of epidemiological data in understanding infectious diseases dynamics among travellers and migrants, emphasising how demographic shifts, migration trends and healthcare policies affect disease profiles. Comprehensive data play an essential role in enhancing public health policies and travel advice.

REGULAR LOW-DOSE CAFFEINE SUPPLEMENTATION DURING TRAINING DOES NOT PROVIDE ADDITIONAL BENEFIT TO SUBSEQUENT EXERCISE PERFORMANCE IN AUSTRALIAN RULES FOOTBALL ATHLETES

INTRODUCTION &amp; AIMS Acute caffeine supplementation can improve exercise types like those completed by Australian Rules football (ARF) players during training. Hypothetically athletes could implement caffeine supplementation prior to training, allowing them to complete more training volume, improving adaptation and subsequent exercise performance. This study aimed to investigate the effect of regular low-dose caffeine ingestion pre-training during a training block on subsequent exercise performance. METHODS Twenty-nine male semi-professional ARF players were randomly allocated to a caffeine or placebo group. The four-week intervention period involved participants ingesting 2 mg·kg·BM-1 of caffeine or a placebo 60 min prior to two of their three weekly training sessions, which incorporated sport-specific conditioning and skills training. To assess exercise performance, a battery of tests was used before and after the intervention period including the Yo-Yo Intermittent Recovery Test Level 2 (YYIRT2), 20 m sprint and vertical jump (VJ). Performance differences were assessed using a linear mixed-effect model. RESULTS Mean session rating of perceived exertion (p = .24) and total training load (p =.53) were not different between caffeine and placebo groups over the intervention. There were no significant time x condition interaction effects for YYIRT2 accumulated distance (p = .87), or 5, 10 and 20 m sprint times (p =.06 - .44), however both caffeine and placebo groups improved YYIRT2 distance and sprint times following four weeks of training (p &amp;lt; 0.01). There was a significant effect for time showing decreased VJ performance (p &amp;lt; 0.01), with greater reductions in the placebo group (p = .03). CONCLUSION It is more beneficial to implement an effective training program for athletes rather than focusing effort on regular low-dose caffeine supplementation to augment the training stimulus. The training stimulus itself is typically greater for developing endurance and sprint effort performance, with supplemental caffeine showing no additional performance benefit.

Limb Position Influences Peripheral Arterial Stiffness Reduction with Reactive Hyperemia

Reactive hyperemia can acutely reduce peripheral arterial stiffness. The reduction in peripheral arterial stiffness with reactive hyperemia has been suggested to be flow dependent. However, no previous studies have manipulated the magnitude of hyperemia. We manipulated blood flow by altering limb position to test the hypothesis that a larger increase in blood flow would lead to a greater reduction in peripheral arterial stiffness. Fourteen healthy young adults (5 women; age: 25 ± 5 years; mean ± SD) were included in this study. Peripheral arterial stiffness assessed via brachial to radial pulse wave velocity (PWV) was measured by placing pulse tonometers simultaneously over the brachial and radial arteries. Doppler ultrasound was used to measure brachial arterial blood flow. Arterial blood pressure was continuously monitored via photoplethysmography on the middle finger of the contralateral hand. Reactive hyperemia was performed with the right arm positioned below (≍50°) and above (≍50°) heart level using a rapid-release cuff positioned on the upper arm, inflated to 220 mmHg, sustained for 5 min, then released. Measurements were recorded before cuff inflation and at 5, 15, and 30 min after cuff release. Repeated measures ANOVA revealed a significant condition effect (p&lt;0.01) with peripheral PWV higher with the arm below the heart. There was a significant time x condition interaction (p&lt;.05). At 5-min after reactive hyperemia, peripheral PWV was reduced more with the arm below the heart (9.58 ±1.65 to 7.26 ± 1.51 m/sec) than above the heart (7.08 ± 1.79 to 5.88 ± 1.43 m/sec). Mean arterial pressure did not change across time points (p&gt;0.05). Peak brachial artery blood flow was greater with the arm below the heart (477.37 ± 145 vs 368.64 ± 137 ml/min; p&lt;.001). The results show that reactive hyperemia produces an acute reduction in brachial to radial PWV. The reduction in peripheral arterial stiffness was greater when the arm was below the heart. The mechanism for position-related differences in the reduction in peripheral arterial stiffness with reactive hyperemia may be associated with the magnitude of increase in blood flow. REJ was supported by National Heart, Lung, and Blood Institute (5T32HL134634-04). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of 3-nitrooxypropanol (3-NOP, Bovaer®10) and whole cottonseed on milk production and enteric methane emissions from dairy cows under Swiss management conditions

The objective of this study was to determine the potential effect and interaction of 3- nitrooxypropanol (3-NOP; Bovaer®) and whole cottonseed (WCS) on lactational performance, and enteric methane (CH4) emission of dairy cows. A total of 16 multiparous cows, including 8 Holstein Friesian (HF) and 8 Brown Swiss (BS) [224 ± 36 d in milk, 26 ± 3.7 kg milk yield], were used in a split-plot design, where the main plot was the breed of cows. Within each subplot, cows were randomly assigned to a treatment sequence in a replicated 4 × 4 Latin Square design with 2 × 2 factorial arrangements of treatments with 4, 24-d periods. The experimental treatments were: 1) Control (basal TMR), 2) 3-NOP (60 mg/kg TMR DM), 3) WCS (5% TMR DM), and 4) 3-NOP + WCS. The treatment diets were balanced for ether extract, crude protein, and NDF contents (4%, 16%, and 43% of TMR DM, respectively). The basal diets were fed twice daily at 0800 and 1800 h. Dry matter intake (DMI) and milk yield were measured daily, and enteric gas emissions were measured (using the GreenFeed system) during the last 3 d of each 24-d experimental period when animals were housed in tie stalls. There was no difference in DMI on treatment level, whereas the WCS treatment increased ECM yield and milk fat yield. There was no interaction of 3-NOP and WCS for any of the enteric gas emission parameters, but 3-NOP decreased CH4 production (g/d), CH4 yield (g/kg DMI), and CH4 intensity (g/kg ECM) by 13, 14 and 13%, respectively. Further, an unexpected interaction of breed by 3-NOP was observed for different enteric CH4 emission metrics: HF cows had a greater CH4 mitigation effect compared with BS cows for CH4 production (g/d; 18 vs. 8%), CH4 intensity (g/kg MY; 19% vs. 3%) and CH4 intensity (g/kg ECM; 19 vs. 4%). Hydrogen production was increased by 2.85 folds in HF and 1.53 folds in BS cows receiving 3-NOP. Further, there was a 3-NOP ' Time interaction for both breeds. In BS cows, 3-NOP tended to reduce CH4 production by 18% at around 4 h after morning feeding but no effect was observed at other time points. In HF cows, the greatest mitigation effect of 3-NOP (29.6%) was observed immediately after morning feeding and it persisted at around 23% to 26% for 10 h until the second feed provision, and 3 h thereafter, in the evening. In conclusion, supplementing 3-NOP at 60 mg/kg DM to a high fiber diet resulted in 18 to 19% reduction in enteric CH4 emission in Swiss Holstein Friesian cows. The lower response to 3-NOP by BS cows was unexpected and has not been observed in other studies. These results should be interpreted with caution due to low number of cows per breed. Lastly, supplementing WCS at 5% of DM improved ECM and milk fat yield but did not enhance CH4 inhibition effect of 3-NOP of dairy cows.

Cooperative AI training for cardiothoracic segmentation in computed tomography: An iterative multi-center annotation approach

PurposeRadiological reporting is transitioning to quantitative analysis, requiring large-scale multi-center validation of biomarkers. A major prerequisite and bottleneck for this task is the voxelwise annotation of image data, which is time-consuming for large cohorts. In this study, we propose an iterative training workflow to support and facilitate such segmentation tasks, specifically for high-resolution thoracic CT data. MethodsOur study included 132 thoracic CT scans from clinical practice, annotated by 13 radiologists. In three iterative training experiments, we aimed to improve and accelerate segmentation of the heart and mediastinum. Each experiment started with manual segmentation of 5–25 CT scans, which served as training data for a nnU-Net. Further iterations incorporated AI pre-segmentation and human correction to improve accuracy, accelerate the annotation process, and reduce human involvement over time. ResultsResults showed consistent improvement in AI model quality with each iteration. Resampled datasets improved the Dice similarity coefficients for both the heart (DCS 0.91 [0.88; 0.92]) and the mediastinum (DCS 0.95 [0.94; 0.95]). Our AI models reduced human interaction time by 50 % for heart and 70 % for mediastinum segmentation in the most potent iteration. A model trained on only five datasets achieved satisfactory results (DCS > 0.90). ConclusionsThe iterative training workflow provides an efficient method for training AI-based segmentation models in multi-center studies, improving accuracy over time and simultaneously reducing human intervention. Future work will explore the use of fewer initial datasets and additional pre-processing methods to enhance model quality.

Orientation of IMF Discontinuity Normals Across the Solar Cycles

AbstractTransient events like hot flow anomalies and foreshock bubbles are common in the Earth's foreshock. These foreshock transients may play an important role in the solar wind‐magnetosphere interaction. They typically occur when backstreaming ions accumulate at the intersection of interplanetary magnetic field (IMF) discontinuities with the bow shock. Discontinuity orientations play a key role in determining when and where transients form in the foreshock and strike the magnetopause. They also play a role in determining the amplitude, and significance, of individual transients. We investigate properties of the IMF discontinuity normals across two solar cycles. We compare Advanced Composition Explorer (ACE) IMF discontinuity observations for 2001, 2002, 2012, and 2014 (solar maximum) and 2008, 2009, 2019, and 2020 (solar minimum). We employ both the Minimum variance analysis (MVA) and Cross‐product methods to determine phase front normals. Most discontinuity normals point earthward and dawnward at longitudes ranging from 180° to 250°. A greater range of normal can be seen during solar minimum than during solar maximum. Normals lie further from the Sun‐Earth line when solar wind densities are low and velocities are high. This provides a natural explanation for the observed tendency of transients to occur for low solar wind densities and high velocities in terms of longer discontinuity interaction times with the bow shock.

Application of Edible Film Whey with Curcuma domestica Val Extract to Caramel Candy: Storage Time and Temperature Study

This study aimed to explore caramel candy with edible film whey as packaging and evaluate the effects of interaction time (7, 14, and 21 days) and storage temperature (room and refrigerator) on nutritional value (moisture, protein, fat, and ash content) and sensory properties (taste, color, aroma, and texture). The results showed a significant difference (P<0.05) in storage time for moisture and fat content, but not significantly different (P>0.05) in protein and ash content. In the sensory evaluation, the difference in storage time and temperature did not affect the sensory properties (color, aroma, and texture), except for the taste parameters. In conclusion, caramel candy can be wrapped in edible films with the addition of Curcuma domestica Val extract at a storage time of up to 14 days at refrigerator temperatures.

Eight-Week Creatine-Glucose Supplementation Alleviates Clinical Features of Long COVID.

Preliminary studies demonstrated beneficial effects of dietary creatine across different post-viral fatigue syndromes. Creatine is often co-administered with glucose to improve its potency yet whether glucose boost the efficacy of creatine in long COVID remains currently unknown. In this report, we investigate the effects of 8-wk creatine intake with and without glucose on patient-reported outcomes, exercise tolerance, and tissue creatine levels in patients with long COVID. Fifteen male and female long COVID adult patients (age 39.7±16.0 y; 9 women) with moderate fatigue and at least one of additional long COVID-related symptoms volunteered to participate in this randomized controlled parallel-group interventional trial. All patients were allocated in a double-blind parallel-group design (1 : 1 : 1) to receive creatine (8 g of creatine monohydrate per day), a mixture of creatine and glucose (8 g of creatine monohydrate and 3 g of glucose per day), or placebo (3 g of glucose per day) t.i.d. during an 8-wk intervention interval. Two-way ANOVA with repeated measures (treatment vs. time interaction) revealed significant differences in changes in total creatine levels between the groups, showing an interaction effect at two brain locations (right precentral white matter F=34.740, p=0.008; partial η2=0.72; left paracentral grey matter F=19.243, p=0.019; partial η2=0.88), with creatine and creatine-glucose outcompeted placebo to elevate creatine levels at these two locations. Several long COVID symptoms (including body aches, breathing problems, difficulties concentrating, headache, and general malaise) were significantly reduced in creatine-glucose group at 8-wk follow-up (p≤0.05); the effect sizes for reducing body aches, difficulties concentrating, and headache were 1.33, 0.80, and 1.12, respectively, suggesting a large effect of creatine-glucose mixture for these outcomes. Our preliminary findings suggest that supplying exogenous creatine with glucose could be recommended as an effective procedure in replenishing brain creatine pool and alleviating long COVID features in this prevalent condition.

Cassava starch modified montmorillonite - an efficient material for removal of crystal violet dye from contaminated aqueous solution

Because of grave effects on human health and the ecosystem, dye wastewater is exigent to be treated before its access to the environment. Removal of dyes from wastewater is one of the most important steps to eliminate its harmfulness. In this study, montmorillonite (MMT), a clay mineral with numerous applications in catalytic and coating purposes, was modified to form a new adsorbent for the removal of crystal violet (CV) dye from contaminated aqueous solution. Vietnamese cassava starch which is biodegradable, renewable, sustainable and affordable, was used as a modifier for MMT. The modified MMT was characterized by Fourier-transformed infrared (FT-IR) and X-ray diffraction (XRD) spectroscopic methods. Its morphology and structure were observed by Scanning electron microscopy (SEM). In addition, the effects of pH, interaction time, adsorbent concentration and temperature on the physico-chemical adsorption process on the basis surface of the material, have been investigated. Langmuir and Freundlich models were applied to analyze the adsorption values of dye solutions at the time of equilibrium. The results indicated that the modified MMT possessed the spherical shape, with particles on the surface in a wide size range. Investigation on the ideal removal conditions for modified MMT showed that it removed the crystal violet dye with maximum adsorption at pH value of 7 and concentration of 101.1 mg/g after 1 hour of interaction. Moreover, the Langmuir adsorption isotherm model was compatible with all results and the adsorption kinetics followed the pseudo-second-order model. Starch modified MMT should be promising for dye removal from wastewater.

영재 사사과정에서 공학도구를 활용한 미적분 및 미분방정식 탐구 지도 사례

The purpose of this study is to present a year-long instructional case study of middle school mathematically gifted students in Science Gifted Education Center using technological devices to explore mathematical models based oncalculus and differential equation, and to draw implications for gifted education. In the classes conducted in this study, technological devices were used to compute expressions and visualize graphs. The use of technological devices reduced the amount of time spent on calculations and graphing, allowing more time for interpretation and discussion of models. As a result, students understood the calculus and differential equation models and interpreted the models in various ways using graphs based on abundant discussion time. The results of this study show that it is possible to explore calculus and differential equation models at the middle school level by using technological devices. Furthermore, visualization with technological devices provides opportunities for observation and discovery of mathematics and allows for plentiful discussion and interpretation by securing time for interaction among students, so there is a need for more active use of technological devices in gifted classes.

A Study of Adjacent Intersection Correlation Based on Temporal Graph Attention Network.

Traffic state classification and relevance calculation at intersections are both difficult problems in traffic control. In this paper, we propose an intersection relevance model based on a temporal graph attention network, which can solve the above two problems at the same time. First, the intersection features and interaction time of the intersections are regarded as input quantities together with the initial labels of the traffic data. Then, they are inputted into the temporal graph attention (TGAT) model to obtain the classification accuracy of the target intersections in four states-free, stable, slow moving, and congested-and the obtained neighbouring intersection weights are used as the correlation between the intersections. Finally, it is validated by VISSIM simulation experiments. In terms of classification accuracy, the TGAT model has a higher classification accuracy than the three traditional classification models and can cope well with the uneven distribution of the number of samples. The information gain algorithm from the information entropy theory was used to derive the average delay as the most influential factor on intersection status. The correlation from the TGAT model positively correlates with traffic flow, making it interpretable. Using this correlation to control the division of subareas improves the road network's operational efficiency more than the traditional correlation model does. This demonstrates the effectiveness of the TGAT model's correlation.

Further Investigation of CO2 Quasi-Dry Fracturing in Shale Reservoirs—An Experimental Study

The physical properties of shale reservoirs are typically poor, necessitating the use of fracturing technology for effective development. However, the high clay content prevalent in shale formations poses significant challenges for conventional hydraulic fracturing methods. To address this issue, CO2-based fracturing fluid has been proposed as an alternative to mitigate the damage caused by water-based fracturing fluids. In this paper, the applicability of quasi-dry CO2 fracturing in shale reservoirs is examined from three key perspectives: the viscosity of CO2 fracturing fluid, the fracture characteristics induced by the CO2 fracture fluid, and the potential reservoir damage caused by the fracturing fluid. Firstly, the viscosity of CO2 fracturing fluid was determined by a rheological experiment. Rheological tests revealed that the viscosity of CO2 fracturing fluid was significantly influenced by the water–carbon ratio. Specifically, when the water–carbon ratio was 30:70, the maximum viscosity observed could reach 104 mPa·s. Moreover, increasing reservoir temperature resulted in decreased fracturing fluid viscosity, with a 40 °C temperature rise causing a 20% viscosity reduction. Secondly, matrix permeability tests were conducted to investigate permeability alteration during CO2 fracturing fluid invasion. Due to the weak acidity of CO2-based fracturing fluid, the permeability reduction induced by clay hydration was inhibited, and an increase in permeability was observed after a 3-day duration. However, the matrix permeability tends to decrease as the interaction time is prolonged, which means prolonged soaking time can still cause formation damage. Finally, triaxial fracturing experiments facilitated by a three-axis servo pressure device were conducted. The fracture properties were characterized using computed tomography (CT), and 3D reconstruction of fractured samples was conducted based on the CT data. The results demonstrate that CO2 fracturing fluid effectively activates weak cementation surfaces in the rock, promoting the formation of larger and more complex fractures. Hence, CO2 quasi-dry fracturing technology emerges as a method with significant potential, capable of efficiently stimulating shale reservoirs, although a reasonable soaking time is necessary to maximize hydrocarbon production.

Nanoparticle Anisotropy Increases Targeting Interactions on Live-Cell Membranes.

This paper describes how branch lengths of anisotropic nanoparticles can affect interactions between grafted ligands and cell-membrane receptors. Using live-cell, single-particle tracking, we found that DNA aptamer-gold nanostar nanoconstructs with longer branches showed improved binding efficacy to human epidermal growth factor receptor 2 (HER2) on cancer cell membranes. Inhibiting nanoconstruct-HER2 binding promoted nonspecific interactions, which increased the rotational speed of long-branched nanoconstructs but did not affect that of short-branched constructs. Bivariate analysis of the rotational and translational dynamics showed that longer branch lengths increased the ratio of targeting to nontargeting interactions. We also found that longer branches increased the nanoconstruct-cell interaction times before internalization and decreased intracellular trafficking velocities. Differences in binding efficacy revealed by single-particle dynamics can be attributed to the distinct protein corona distributions on short- and long-branched nanoconstructs, as validated by transmission electron microscopy. Minimal protein adsorption at the high positive curvature tips of long-branched nanoconstructs facilitated binding of DNA aptamer ligands to HER2. Our study reveals the significance of nanoparticle branch length in regulating local chemical environment and interactions with live cells at the single-particle level.

Effect of Service-Learning Physical Activity Programs on Kinesiology Students’ Attitudes Toward People With Disabilities

Background: Service-learning (SL) programs have been shown to be effective for college students in developing positive attitudes toward people with disabilities (PWDs). Such positive attitudes are particularly important for Kinesiology (KIN) students as they are trained to become future health and fitness professionals. Purpose: The present study investigated the effect of a 10-week in-person versus virtual SL program on KIN students’ attitudes toward PWD. Methodology/Approach: A pre- postintervention, three-way, analysis of variance was utilized. This 3 × 2 mixed model design was utilized to assess students’ attitudes toward PWD with three independent variables (in-person program, virtual program, and control) on two dependent variables (pre and post). Findings/Conclusions: There was significant Group × Time interaction. The between-group comparison showed a significant increase in Attitudes Toward Disabled Person scale score in the in-person SL group ( p &lt; .05) compared to non-SL group. There were no significant differences in the virtual SL group. Implications: These results indicate that in-person SL is effective for improving students’ attitudes toward PWD, whereas virtual programs may not be as effective as in-person. In-person SL programs for KIN students may positively improve their attitudes toward PWD thus ameliorating interpersonal skills and creating more inclusive health and fitness professionals. KIN programs should consider SL programs with an emphasis on PWDs.