Influence of the body position on skin blood microcirculation measured by wearable laser Doppler sensors

2021 ◽  
Author(s):  
Y. I. Loktionova ◽  
E. V. Zharkikh ◽  
A. A. Fedorovich ◽  
M. A. Mikhailova ◽  
J. A. Popova ◽  
...  
Keyword(s):  
Body Position ◽  
The Body ◽  
Laser Doppler ◽  
Blood Microcirculation

scholarly journals Body Position Affects Capillary Blood Flow Regulation Measured with Wearable Blood Flow Sensors

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 436
Author(s):  
Andrey A. Fedorovich ◽  
Yulia I. Loktionova ◽  
Elena V. Zharkikh ◽  
Maria A. Mikhailova ◽  
Julia A. Popova ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Body Position ◽  
Blood Perfusion ◽  
The Body ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Postural Changes ◽  
Skin Blood Perfusion ◽  
The Right

In this study we demonstrate what kind of relative alterations can be expected in average perfusion and blood flow oscillations during postural changes being measured in the skin of limbs and on the brow of the forehead by wearable laser Doppler flowmetry (LDF) sensors. The aims of the study were to evaluate the dynamics of cutaneous blood perfusion and the regulatory mechanisms of blood microcirculation in the areas of interest, and evaluate the possible significance of those effects for the diagnostics based on blood perfusion monitoring. The study involved 10 conditionally healthy volunteers (44 ± 12 years). Wearable laser Doppler flowmetry monitors were fixed at six points on the body: two devices were fixed on the forehead, on the brow; two were on the distal thirds of the right and left forearms; and two were on the distal thirds of the right and left lower legs. The protocol was used to record three body positions on the tilt table for orthostatic test for each volunteer in the following sequence: (a) supine body position; (b) upright body position (+75°); (c) tilted with the feet elevated above the head and the inclination of body axis of 15° (−15°, Trendelenburg position). Skin blood perfusion was recorded for 10 min in each body position, followed by the amplitude–frequency analysis of the registered signals using wavelet decomposition. The measurements were supplemented with the blood pressure and heart rate for every body position analysed. The results identified a statistically significant transformation in microcirculation parameters of the average level of skin blood perfusion and oscillations of amplitudes of neurogenic, myogenic and cardiac sensors caused by the postural changes. In paper, we present the analysis of microcirculation in the skin of the forehead, which for the first time was carried out in various positions of the body. The area is supplied by the internal carotid artery system and can be of particular interest for evaluation of the sufficiency of blood supply for the brain.

Obesity impairs performing and learning a timing perception task regardless of the body position

2021 ◽  
Author(s):  
Fernanda Mottin Refinetti ◽  
Ricardo Drews ◽  
Umberto Cesar Corrêa ◽  
Flavio Henrique Bastos
Keyword(s):  
Body Position ◽  
The Body ◽  
Perception Task ◽  
Timing Perception

Lepeophtheirus salmonis (Krøyer, 1837): second nauplius and copepodid locomotor appendages, surface areas and possible appendage functions

Crustaceana ◽  
2013 ◽  
Vol 86 (13-14) ◽  
pp. 1695-1710 ◽  
Author(s):  
Susan E. Allen ◽  
A. G. Lewis
Keyword(s):  
Body Position ◽  
Ventral Surface ◽  
Total Surface Area ◽  
The Body ◽  
Lepeophtheirus Salmonis ◽  
Sinking Rate ◽  
Surface Areas ◽  
Thoracic Legs ◽  
Two Stages ◽  
Suitable Location

Locomotor appendage-body relationships were used to examine whether swimming or reduction in sinking rate is the more important function in the second nauplius and copepodid stages of Lepeophtheirus salmonis (Krøyer, 1837). Except for the similarity in swimming appendage surface areas without setae, the appendages of the two stages are morphologically distinct. Although the nauplius is smaller than the copepodid it has long slender appendages that, with setae, provide greater total surface area than the paddle-shaped copepodid thoracic legs. Copepodid thoracic legs are more similar to those used for swimming by planktonic copepods although with more limited propulsion capability. Naupliar appendages project from the body while copepodid appendages can be folded against the ventral surface, improving hydrodynamic flow as well as body position after attachment to a host. Both copepodid and naupliar appendages are of sufficient size that they should provide escape velocities of more than 100 mm ⋅ s−1. The nature and display of the naupliar appendages suggest they could be used to reduce sinking rate by as much as 64%, reducing the need to swim to maintain a suitable location in the water. Although copepodid thoracic legs could reduce sinking rate by over 40%, their position on the ventral surface and the nature of other appendages suggests a more important use, for orientation and attachment once a host is located.

scholarly journals A faster escape does not enhance survival in zebrafish larvae

2017 ◽  
Vol 284 (1852) ◽  
pp. 20170359 ◽  
Author(s):  
Arjun Nair ◽  
Christy Nguyen ◽  
Matthew J. McHenry
Keyword(s):  
High Speed ◽  
Larval Fish ◽  
Body Position ◽  
Three Dimensional ◽  
Limited Range ◽  
The Body ◽  
Model Parameters ◽  
Fish Prey ◽  
Zebrafish Larvae ◽  
Fish Predators

An escape response is a rapid manoeuvre used by prey to evade predators. Performing this manoeuvre at greater speed, in a favourable direction, or from a longer distance have been hypothesized to enhance the survival of prey, but these ideas are difficult to test experimentally. We examined how prey survival depends on escape kinematics through a novel combination of experimentation and mathematical modelling. This approach focused on zebrafish ( Danio rerio ) larvae under predation by adults and juveniles of the same species. High-speed three-dimensional kinematics were used to track the body position of prey and predator and to determine the probability of behavioural actions by both fish. These measurements provided the basis for an agent-based probabilistic model that simulated the trajectories of the animals. Predictions of survivorship by this model were found by Monte Carlo simulations to agree with our observations and we examined how these predictions varied by changing individual model parameters. Contrary to expectation, we found that survival may not be improved by increasing the speed or altering the direction of the escape. Rather, zebrafish larvae operate with sufficiently high locomotor performance due to the relatively slow approach and limited range of suction feeding by fish predators. We did find that survival was enhanced when prey responded from a greater distance. This is an ability that depends on the capacity of the visual and lateral line systems to detect a looming threat. Therefore, performance in sensing, and not locomotion, is decisive for improving the survival of larval fish prey. These results offer a framework for understanding the evolution of predator–prey strategy that may inform prey survival in a broad diversity of animals.

scholarly journals The Body Position Spatial Task, a Test of Whole-Body Spatial Cognition: Comparison Between Adults With and Without Parkinson Disease

2018 ◽  
Vol 32 (11) ◽  
pp. 961-975 ◽  
Author(s):  
Jessica Battisto ◽  
Katharina V. Echt ◽  
Steven L. Wolf ◽  
Paul Weiss ◽  
Madeleine E. Hackney
Keyword(s):  
Parkinson Disease ◽  
Spatial Cognition ◽  
Body Position ◽  
Spatial Task ◽  
The Body ◽  
Whole Body

An Improved Body-Exact Method to Predict Large Amplitude Ship Roll Responses

2018 ◽  
Author(s):  
Rahul Subramanian ◽  
Naga Venkata Rakesh ◽  
Robert F. Beck
Keyword(s):  
Incident Wave ◽  
Large Amplitude ◽  
Nonlinear Models ◽  
Body Position ◽  
Computational Cost ◽  
Offshore Structures ◽  
The Body ◽  
Surface Boundary ◽  
Strip Theory ◽  
New Formulation

Accurate prediction of the roll response is of significant practical relevance not only for ships but also ship type offshore structures such as FPSOs, FLNGs and FSRUs. This paper presents a new body-exact scheme that is introduced into a nonlinear direct time-domain based strip theory formulation to study the roll response of a vessel subjected to moderately large amplitude incident waves. The free surface boundary conditions are transferred onto a representative incident wave surface at each station. The body boundary condition is satisfied on the instantaneous wetted surface of the body below this surface. This new scheme allows capturing nonlinear higher order fluid loads arising from the radiated and wave diffraction components. The Froude-Krylov and hydrostatic loads are computed on the intersection surface of the exact body position and incident wave field. The key advantage of the methodology is that it improves prediction of nonlinear hydrodynamic loads while keeping the additional computational cost small. Physical model tests have been carried out to validate the computational model. Fairly good agreement is seen. Comparisons of the force components with fully linear and body-nonlinear models help in bringing out the improvements due to the new formulation.

scholarly journals Embodiment of sleep-related words: evidence from event-related potentials

2020 ◽  
Author(s):  
Mareike J. Hülsemann ◽  
Björn Rasch
Keyword(s):  
Cognitive Processing ◽  
Word Processing ◽  
Body Position ◽  
Event Related Potentials ◽  
Event Related Potential ◽  
The Body ◽  
Semantic Meaning ◽  
Related Potentials ◽  
Multimodal Networks ◽  
Lying Down

AbstractOur thoughts, plans and intentions can influence physiological sleep, but the underlying mechanisms are unknown. According to the theoretical framework of “embodied cognition”, the semantic content of cognitive processes is represented by multimodal networks in the brain which also include body-related functions. Such multimodal representation could offer a mechanism which explains mutual influences between cognition and sleep. In the current study we tested whether sleep-related words are represented in multimodal networks by examining the effect of congruent vs. incongruent body positions on word processing during wakefulness.We experimentally manipulated the body position of 66 subjects (50 females, 16 males, 19-40 years old) between standing upright and lying down. Sleep- and activity-related words were presented around the individual speech recognition threshold to increase task difficulty. Our results show that word processing is facilitated in congruent body positions (sleep words: lying down and activity words: standing upright) compared with incongruent body positions, as indicated by a reduced N400 of the event-related potential (ERP) in the congruent condition with the lowest volume. In addition, early sensory components of the ERP (N180 and P280) were enhanced, suggesting that words were also acoustically better understood when the body position was congruent with the semantic meaning of the word. However, the difference in ERPs did not translate to differences on a behavioural level.Our results support the prediction of embodied processing of sleep- and activity-related words. Body position potentially induces a pre-activation of multimodal networks, thereby enhancing the access to the semantic concepts of words related to current the body position. The mutual link between semantic meaning and body-related function could be a key element in explaining influences of cognitive processing on sleep.

Reappraisal of Factors Disturbing the Relationship between Body Water Volumes and Total Body Electrical Resistance in Patients on Hemodialysis

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Schotman JM ◽  
◽  
Reichert LJM ◽  
de Boer H ◽  
van Borren MMGJ ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Body Position ◽  
Body Water ◽  
The Body ◽  
Current Evidence ◽  
Electrode Position ◽  
Fluid Redistribution ◽  
Interpretation Errors ◽  
Water Volumes ◽  
Total Body

Background: Measurements of Total Body Electrical Resistance (TBER) are used to improve fluid balance management in patients on Hemodialysis (HD). This approach is based on the inverse relation that exists between TBER and body water volumes. Interpretation errors may occur if TBER measurements are affected by factors that are not related to changes in body water. Aim of this paper was to provide an overview of the methodological artifacts commonly encountered in a clinical setting, and to strengthen current evidence of their disturbing effects by performing additional experiments. Methods: This study includes an analysis of available literature data, supplemented with additional experiments in healthy adults and patients. A cutoff of 2.7% was used to classify changes in TBER as significant within individual subjects. Results: Electrode position, electrode interference, differences of measurements performed at the right or left side of the body, presence of orthopedic prosthesis located in the limbs, fluid redistribution induced by longterm changes in body position, and electrolyte abnormalities were the main disturbing factors that can induce a significant change in TBER. Other factors either had no significant disturbing effect or could be easily avoided. Conclusion: TBER measurements require a high degree of standardization to minimize interpretation errors.

Effect of body position on spontaneous respiratory rate and tidal volume in patients with obesity, abdominal distension and ascites

1994 ◽  
Vol 3 (2) ◽  
pp. 102-106 ◽  
Author(s):  
SM Burns ◽  
MB Egloff ◽  
B Ryan ◽  
R Carpenter ◽  
JE Burns
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Breathing Pattern ◽  
Body Position ◽  
Abdominal Distension ◽  
The Body ◽  
Abdominal Distention ◽  
Optimal Position ◽  
Nursing Textbooks ◽  
Spontaneously Breathing

BACKGROUND: Nursing textbooks and tradition suggest that the high-Fowler's position is best to optimize diaphragmatic excursion and effective breathing pattern. The optimal position for intubated patients with obesity, ascites or abdominal distention has yet to be determined but is important because weaning trial outcomes may reflect the effect of position rather than weaning trial tolerance. OBJECTIVE: To determine the body position that optimizes breathing pattern (tidal volume and respiratory rate) in spontaneously breathing, intubated patients with a large abdomen. METHODS: Nineteen intubated patients with abdominal distention, ascites or obesity who were on continuous positive airway pressure or the pressure support ventilation mode were studied in the 0 degrees, 45 degrees, 90 degrees and reverse Trendelenburg's at 45 degrees positions for 5 minutes prior to data collection. RESULTS: The RT at 45 degrees position resulted in a significantly larger tidal volume and lower respiratory rate than the 90 degrees position in intubated, spontaneously breathing patients with a large abdomen. The 45 degrees position resulted in a significantly lower respiratory rate than at 90 degrees; however, no difference in tidal volume was demonstrated. DISCUSSION: A high respiratory rate and low tidal volume potentiates atelectasis and ultimately failure to wean. It is important that the effect of positioning on breathing pattern in intubated patients be determined so that care planning results in optimal outcomes. CONCLUSIONS: The results of this study have implications for the selection of chair and bed positioning during weaning trials.

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