Real-time tracking of ionic nano-domains under shear flow

The behaviour of ions at solid–liquid interfaces underpins countless phenomena, from the conduction of nervous impulses to charge transfer in solar cells. In most cases, ions do not operate as isolated entities, but in conjunction with neighbouring ions and the surrounding solution. In aqueous solutions, recent studies suggest the existence of group dynamics through water-mediated clusters but results allowing direct tracking of ionic domains with atomic precision are scarce. Here, we use high-speed atomic force microscopy to track the evolution of Rb+, K+, Na+ and Ca2+ nano-domains containing 20 to 120 ions adsorbed at the surface of mica in aqueous solution. The interface is exposed to a shear flow able to influence the lateral motion of single ions and clusters. The results show that, when in groups, metal ions tend to move with a relatively slow dynamics, as can be expected from a correlated group motion, with an average residence timescale of ~ 1–2 s for individual ions at a given atomic site. The average group velocity of the clusters depends on the ions’ charge density and can be explained by the ion’s hydration state. The lateral shear flow of the fluid is insufficient to desorb ions, but indirectly influences the diffusion dynamics by acting on ions in close vicinity to the surface. The results provide insights into the dynamics of ion clusters when adsorbed onto an immersed solid under shear flow.

ANALYSIS OF ULTRASOUND IMAGE BIOLOGICAL IMAGE ALGORITHM IN THE RESTORATION OF MUSCLE GROUP MOVEMENT FUNCTION

ABSTRACT Objective: By studying the recognition effect of ultrasonic biological image data analysis on muscle group motion function, the evaluation value and significance of ultrasonic biomedical image combination algorithm on muscle group motion function are discussed. Methods: A Gabor filtering algorithm is proposed to smooth the original image. The MVEF algorithm is used to enhance the ultrasonic image and binary further the image again. Using the principle of the Hove transform, the thickness of the muscle is automatically estimated. Results: The square of correlation coefficients of the manual measurement method, Gabor filtering algorithm and MVEF algorithm are 91.3%, 91.3% and 87.8%, respectively. The difference between the manual measurement and the estimation based on the Gabor filtering algorithm is 1.45 ± 0.48mm. The difference between the results of manual measurement and the MVEF algorithm is 1.38 ± 0.56mm. The computation time of the MVEF algorithm and Gabor algorithm are 5 seconds and 0.3 seconds, respectively. Conclusions: The algorithm proposed in this study can effectively measure the muscle thickness, fast, convenient and accurate, and can reflect the contractility of skeletal muscle well, which is of great value for the recognition and evaluation of muscle group movement function. Level of evidence II; Therapeutic studies - investigation of treatment results.

Collective states and their transitions in football

Movement, positioning and coordination of player formations is a key aspect for the performance of teams within field-based sports. The increased availability of player tracking data has given rise to numerous studies that focus on the relationship between simple descriptive statistics surrounding team formation and performance. While these existing approaches have provided a high-level a view of team-based spatial formations, there is limited research on the nature of collective movement across players within teams and the establishment of stable collective states within game play. This study draws inspiration from the analysis of collective movement in nature, such as that observed within schools of fish and flocking birds, to explore the existence of collective states within the phases of play in soccer. Order parameters and metrics describing group motion and shape are derived from player movement tracks to uncover the nature of the team’s collective states and transitions. This represents a unique addition to the current body of work around the analysis of player movement in team sports. The results from this study demonstrate that sequences of ordered collective behaviours exist with relatively rapid transitions between highly aligned polar and un-ordered swarm behaviours (and vice-versa). Defensive phases of play have a higher proportion of ordered team movement than attacking phases, indicating that movements linked with attacking tactics, such as player dispersion to generate passing and shooting opportunities leads to lower overall collective order. Exploration within this study suggests that defensive tactics, such as reducing the depth or width to close passing opportunities, allows for higher team movement speeds and increased levels of collective order. This study provides a novel view of player movement by visualising the collective states present across the phases of play in football.

Baihe, Dihuang and Baihe Dihuang Tang ameliorates PCPA-Induced Insomnia

Clinical evidence from the practice of traditional Chinese medicine (TCM) has shown that Baihe (BH), Dihuang (DH), and their compatibility, Baihe Dihuang Tang (BDT) can treat insomnia. However, the sedative and hypnotic mechanisms of these therapies have not been established. This study evaluated the sedative-hypnotic mechanisms of BH, DH and BDT in terms of their effects on neurotransmitters, the neuroendocrine system and cation-chloride co-transporters in a p -chlorophenylalanine (PCPA)-induced insomnia mice model. The insomnia mice model was established by intraperitoneal injection of PCPA. Mice were randomly assigned into four groups that were treated with BH, DH and BDT (2.25 g/kg, 2.25 g/kg, 4.5 g/kg) and saline solution (wt., 0.9%). Behavioral analyses showed that, compared to mice in the control group, motion activities of mice with insomnia were significantly reduced, sleep latency was prolonged while sleep duration was shortened. Compared to control mice, 5-HT and KCC2 levels were decreased, whereas CRH and ACTH levels were elevated in the insomniac mice. Treatment with BH, DH and BDT ameliorated the symptoms of insomnia and significantly reversed the abnormal levels of the aforementioned neurotransmitters. Notably, BDT effects were the most obvious. These results indicate that BH, DH and BDT improves insomniac symptoms by modifying neurotransmitters levels, the neuroendocrine system and cation-chloride co-transporters.

Phospholipids in motion: High Resolution 31P NMR Field Cycling Studies

High resolution field cycling ³¹P NMR spin-lattice relaxometry, where the sample is excited at high field, shuttled in the magnet bore for low field relaxation, then shuttled back to high field for readout of the residual magnetization, provides data on phospholipid dynamics and structure. In the field range from 11.74 down to 0.003 T three dipolar nuclear magnetic relaxation dispersions (NMRDs) and one due to ³¹P chemical shift anisotropy contribute to R₁of phospholipids_. Extraction of correlation times and maximum relaxation amplitudes for these NMRDs provides (1) lateral diffusion constants for different phospholipids in the same bilayer (illustrated with phospholipase C binding), (2) estimates of how additives alter the motion of the phospholipid about its long axis (looking at cholesterol effects), and (3) an average ³¹P – ¹H angle with respect to the bilayer normal, which reveals that polar head group motion is not restricted on a µs timescale. Although this deals exclusively with phospholipids in small unilamellar vesicles, these same NMRDs can be measured for phospholipids in micelles and nanodiscs, making this technique useful for monitoring lipid behavior in a variety of structures.

Phospholipids in motion: High Resolution 31P NMR Field Cycling Studies

High resolution field cycling ³¹P NMR spin-lattice relaxometry, where the sample is excited at high field, shuttled in the magnet bore for low field relaxation, then shuttled back to high field for readout of the residual magnetization, provides data on phospholipid dynamics and structure. In the field range from 11.74 down to 0.003 T three dipolar nuclear magnetic relaxation dispersions (NMRDs) and one due to ³¹P chemical shift anisotropy contribute to R₁of phospholipids_. Extraction of correlation times and maximum relaxation amplitudes for these NMRDs provides (1) lateral diffusion constants for different phospholipids in the same bilayer (illustrated with phospholipase C binding), (2) estimates of how additives alter the motion of the phospholipid about its long axis (looking at cholesterol effects), and (3) an average ³¹P – ¹H angle with respect to the bilayer normal, which reveals that polar head group motion is not restricted on a µs timescale. Although this deals exclusively with phospholipids in small unilamellar vesicles, these same NMRDs can be measured for phospholipids in micelles and nanodiscs, making this technique useful for monitoring lipid behavior in a variety of structures.

Phospholipids in motion: High Resolution 31P NMR Field Cycling Studies

High resolution field cycling ³¹P NMR spin-lattice relaxometry, where the sample is excited at high field, shuttled in the magnet bore for low field relaxation, then shuttled back to high field for readout of the residual magnetization, provides data on phospholipid dynamics and structure. In the field range from 11.74 down to 0.003 T three dipolar nuclear magnetic relaxation dispersions (NMRDs) and one due to ³¹P chemical shift anisotropy contribute to R₁of phospholipids_. Extraction of correlation times and maximum relaxation amplitudes for these NMRDs provides (1) lateral diffusion constants for different phospholipids in the same bilayer (illustrated with phospholipase C binding), (2) estimates of how additives alter the motion of the phospholipid about its long axis (looking at cholesterol effects), and (3) an average ³¹P – ¹H angle with respect to the bilayer normal, which reveals that polar head group motion is not restricted on a µs timescale. Although this deals exclusively with phospholipids in small unilamellar vesicles, these same NMRDs can be measured for phospholipids in micelles and nanodiscs, making this technique useful for monitoring lipid behavior in a variety of structures.

Impacts of Motion-Based Technology on Balance, Movement Confidence, and Cognitive Function Among People With Dementia or Mild Cognitive Impairment: Protocol for a Quasi-Experimental Pre- and Posttest Study

Background While exercise can benefit the health and well-being of people with dementia or mild cognitive impairment, many exercise programs offered to this population are passive, unengaging, and inaccessible, resulting in poor adherence. Motion-based technologies are increasingly being explored to encourage exercise participation among people with dementia or mild cognitive impairment. However, the impacts of using motion-based technologies with people with dementia or mild cognitive impairment on variables including balance, movement confidence, and cognitive function have yet to be determined. Objective The purpose of this study is to examine the impacts of a group motion-based technology intervention on balance, movement confidence, and cognitive function among people with dementia or mild cognitive impairment. Methods In this quasi-experimental pre- and posttest design, we will recruit 24 people with dementia or mild cognitive impairment from 4 adult day programs and invite them to play Xbox Kinect bowling in a group setting, twice weekly for 10 weeks. We will require participants to speak and understand English, be without visual impairment, and be able to stand and walk. At pretest, participants will complete the Mini-Balance Evaluation Systems Test (Mini-BESTest) and the Montreal Cognitive Assessment (MoCA). We will video record participants during weeks 1, 5, and 10 of the intervention to capture behavioral indicators of movement confidence (eg, fluency of motion) through coding. At posttest, the Mini-BESTest and MoCA will be repeated. We will analyze quantitative data collected through the Mini-BESTest and the MoCA using an intent-to-treat analysis, with study site and number of intervention sessions attended as covariates. To analyze the videos, we will extract count and percentage data from the coded recordings. Results This study will address the question of whether a group motion-based technology intervention, delivered in an adult day program context, has the potential to impact balance, movement confidence, and cognitive function among people with dementia or mild cognitive impairment. The project was funded in 2019 and enrollment was completed on February 28, 2020. Data analysis is underway and the first results are expected to be submitted for publication in 2021. Conclusions This study will assess the feasibility and potential benefits of using motion-based technology to deliver exercise interventions to people with dementia or mild cognitive impairment. This work can also be used as the basis for developing specific software and future exercise programs using motion-based technology for people with dementia or mild cognitive impairment, as well as understanding some of the conditions in which these programs can be delivered. International Registered Report Identifier (IRRID) DERR1-10.2196/18209

Pedestrian Models for Robot Motion

We discuss the development of a robot system able to replicate human group motion and show how a pedestrian model may be converted to a robot control system in order to achieve this goal.