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1.
Med Eng Phys ; 107: 103852, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36068033

RESUMO

Upper limb orientation estimation based on Magnetic, Angular Rate, and Gravity sensors considering multiple body segments is presented in this work. The proposal allowed assessing the activity of two or more body segments individually and jointly, regardless of their spatial relationship. A custom-made system was developed incorporating a complementary filter and a proportional-integral control for data sensor merging and, noise and instrumentation error reduction. Two controlled tests were carried out to assess the performance of the system. The former evaluated the response of the method in motionless conditions, while the latter assessed the feasibility to follow trajectories in 3D space. Ten volunteers were recruited to evaluate the system performance in three semi-controlled and daily life task tests. The system was evaluated using the common parameters in motion tracking methods and relied on a digital motion processor. The system's outcome presented a root mean square error in the range of 2.65°-3.98° for the semi-controlled tests and 0.48°-1.389° for the daily life task test. The system tests analysis proved that the proposal permitted obtaining the articulated body chain information of multiple segments when three or more MARG sensors are used.


Assuntos
Algoritmos , Extremidade Superior , Gravitação , Humanos , Movimento (Física)
2.
Exp Brain Res ; 240(10): 2607-2621, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35951095

RESUMO

Humans closely coordinate the grip force exerted on a hand-held object with changes in the load arising from the object's dynamics. Recent work suggests the grip force is responsive to the predictability of the load forces as well. The well-known grip-force-load-force coupling is intermittent when the load arising from volitional movements fluctuates predictably, whereas grip force increases when loads are unpredictable. Here, we studied the influence of expected but uncertain volitional movements on the digit forces during a static grasp. Young, healthy participants used a pinch grasp to hold an instrumented object and track visual targets by moving the object. We quantified the mean grip force, the temporal decline in grip force (slacking), and the coupling between the pressing digit forces that yield the grip force during static prehension with no expectation of movement, and during the static phase of a choice reaction time task, when the participant expected to move the object after a variable duration. Simply expecting to move the object led to sustained (for at least 5 s) higher magnitude and lower slacking in the grip force, and weaker coupling between the pressing digit forces. These effects were modulated by the direction of the expected movement and the object's mass. The changes helped to maintain the safety margin for the current grasp and likely facilitated the transition from static to dynamic object manipulation. Influence of expected actions on the current grasp may have implications for manual dexterity and its well-known loss with age.


Assuntos
Braço , Força da Mão , Dedos , Gravitação , Humanos , Movimento , Desempenho Psicomotor , Volição
3.
Water Sci Technol ; 86(3): 445-456, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35960829

RESUMO

Hydrogen sulphide (H2S) emissions in sewer systems lead to several problems such as corrosion, odour nuisances, and health damage to sewer workers. Although the gas is formed in the liquid phase, its effects are noticeable when released into the sewer atmosphere. Until recently, the lack of analytical procedures for continuous monitoring of H2S in the liquid phase, as well as its toxicity, have challenged the quantification of the mass transfer coefficient under real conditions. Because of this, most studies have mainly focused on batch experiments with artificial wastewater and/or oxygen. The aim of this study was to experimentally determine the overall mass transfer coefficient for H2S during intermittent pumping events common in actual sewer systems, using the two-film theory approach and employing online sensors for liquid and gas phase measurements. The mass transfer coefficient was quantified by carrying out 21 experiments with actual wastewater in a 25 m long gravity pipe of a sewer pilot plant located in Berlin (Germany). Results show that the corrected mass transfer coefficient (KLa20) during a pumping event ranged between 0.1 and 8 h-1 with a median value of 4.2 h-1, within the range of the results obtained by the most common empirical models.


Assuntos
Sulfeto de Hidrogênio , Águas Residuárias , Corrosão , Gravitação , Humanos , Sulfeto de Hidrogênio/análise , Esgotos
4.
J R Soc Interface ; 19(193): 20220266, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35919977

RESUMO

Plant root growth is dramatically reduced in compacted soils, affecting the growth of the whole plant. Through a model experiment coupling force and kinematics measurements, we probed the force-growth relationship of a primary root contacting a stiff resisting obstacle, which mimics the strongest soil impedance variation encountered by a growing root. The growth of maize roots just emerging from a corseting agarose gel and contacting a force sensor (acting as an obstacle) was monitored by time-lapse imaging simultaneously to the force. The evolution of the velocity field along the root was obtained from kinematics analysis of the root texture with a particle image velocimetry derived technique. A triangular fit was introduced to retrieve the elemental elongation rate or strain rate. A parameter-free model based on the Lockhart law quantitatively predicts how the force at the obstacle modifies several features of the growth distribution (length of the growth zone, maximal elemental elongation rate and velocity) during the first 10 min. These results suggest a strong similarity of the early growth responses elicited either by a directional stress (contact) or by an isotropic perturbation (hyperosmotic bath).


Assuntos
Raízes de Plantas , Zea mays , Gravitação , Desenvolvimento Vegetal , Solo
5.
Stud Hist Philos Sci ; 95: 1-27, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35930828

RESUMO

The problem of observables and their supposed lack of change has been significant in Hamiltonian quantum gravity since the 1950s. This paper considers the unrecognized variety of ideas about observables in the thought of constrained Hamiltonian dynamics co-founder Peter Bergmann, who trained many students at Syracuse and invented observables. Whereas initially Bergmann required a constrained Hamiltonian formalism to be mathematically equivalent to the Lagrangian, in 1953 Bergmann and Schiller introduced a novel postulate, motivated by facilitating quantum gravity. This postulate held that observables were invariant under transformations generated by each individual first-class constraint. While modern works rely on Bergmann's authority and sometimes speak of "Bergmann observables," he had much to say about observables, generally interesting and plausible but not all mutually consistent and much of it neglected. On occasion he required observables to be locally defined (not changeless and global); at times he wanted observables to be independent of the Hamiltonian formalism (implicitly contrary to a definition involving separate first-class constraints). But typically he took observables to have vanishing Poisson bracket with each first-class constraint and took this result to be justified by the example of electrodynamics. He expected observables to be analogous to the transverse true degrees of freedom of electromagnetism. Given these premises, there is no coherent concept of observables which he reliably endorsed, much less established. A revised definition of observables that satisfies the requirement that equivalent theories should have equivalent observables using the Rosenfeld-Anderson-Bergmann-Castellani gauge generator G, a tuned sum of first-class constraints that changes the canonical action ∫dt(pq̇-H) by a boundary term. Bootstrapping from theory formulations with no first-class constraints, one finds that the "external" coordinate gauge symmetry of GR calls for covariance (a transformation rule and hence a 4-dimensional Lie derivative for the Poisson bracket), not invariance (0 Poisson bracket), under G (not each first-class constraint separately).


Assuntos
Gravitação , Humanos , Masculino , Tempo
6.
J Sports Sci ; 40(14): 1602-1608, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35786386

RESUMO

This study examined the relationship between perceived bowling intensity, ball release speed and ground reaction force (measured by peak force, impulse and loading rate) in male pace bowlers. Twenty participants each bowled 36 deliveries, split evenly across three perceived intensity zones: low = 70% of maximum perceived bowling effort, medium = 85%, and high = 100%. Peak force and loading rate were significantly different across the three perceived intensity zones in the horizontal and vertical directions (Cohen's d range = 0.14-0.45, p < 0.01). When ball release speed increased, peak force and loading rate also increased in the horizontal and vertical directions (ηp2 = 0.04-0.18, p < 0.01). Lastly, bowling at submaximal intensities (i.e., low - medium) was associated with larger decreases in peak horizontal force (7.9-12.3% decrease), impulse (15.8-21.4%) and loading rate (7.4-12.7%) compared to decreases in ball release speed (5.4-8.3%). This may have implications for bowling strategies implemented during training and matches, particularly for preserving energy and reducing injury risk.


Assuntos
Esportes , Fenômenos Biomecânicos , Gravitação , Humanos , Masculino
7.
Sensors (Basel) ; 22(13)2022 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-35808268

RESUMO

This paper addresses the problem of optimal defense of a high-value unit (HVU) against a large-scale swarm attack. We discuss multiple models for intra-swarm cooperation strategies and provide a framework for combining these cooperative models with HVU tracking and adversarial interaction forces. We show that the problem of defending against a swarm attack can be cast in the framework of uncertain parameter optimal control. We discuss numerical solution methods, then derive a consistency result for the dual problem of this framework, providing a tool for verifying computational results. We also show that the dual conditions can be computed numerically, providing further computational utility. Finally, we apply these numerical results to derive optimal defender strategies against a 100-agent swarm attack.


Assuntos
Gravitação , Incerteza
8.
Int J Pharm ; 622: 121861, 2022 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-35643345

RESUMO

Understanding die filling behaviour of powders is critical in developing optimal formulation and processes in various industries, such as pharmaceuticals and fine chemicals. In this paper, forced die filling is analysed using a graphics processing unit (GPU) based discrete element method (DEM), for which a powder feeder equipped with a wired stirrer is considered. The influences of operating parameters, such as the initial powder bed height, the filling speed, and the stirrer speed, on the die filling performance are systematically explored. It is shown that a larger initial powder bed height leads to a higher filling ratio, which can be attributed to a higher filling intensity; while the deposited particle mass in the die is almost independent of the powder bed height, when the initial fill level is larger than a critical bed height. Additionally, the filling ratio slightly increases with the increase of stirrer speed for cases with a stirrer, while the filling ratios are lower than that without a stirrer, which is attributed to the stirrer occupying some space above the die and reducing the effective discharge area. The obtained results can provide useful information for optimising the feeder system design and the operating condition.


Assuntos
Excipientes , Gravitação , Pós , Tecnologia Farmacêutica/métodos
9.
Biomed Res Int ; 2022: 2636515, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35707376

RESUMO

One of the most well-known methods for solving real-world and complex optimization problems is the gravitational search algorithm (GSA). The gravitational search technique suffers from a sluggish convergence rate and weak local search capabilities while solving complicated optimization problems. A unique hybrid population-based strategy is designed to tackle the problem by combining dynamic multiswarm particle swarm optimization with gravitational search algorithm (GSADMSPSO). In this manuscript, GSADMSPSO is used as novel training techniques for Feedforward Neural Networks (FNNs) in order to test the algorithm's efficiency in decreasing the issues of local minima trapping and existing evolutionary learning methods' poor convergence rate. A novel method GSADMSPSO distributes the primary population of masses into smaller subswarms, according to the proposed algorithm, and also stabilizes them by offering a new neighborhood plan. At this time, each agent (particle) increases its position and velocity by using the suggested algorithm's global search capability. The fundamental concept is to combine GSA's ability with DMSPSO's to improve the performance of a given algorithm's exploration and exploitation. The suggested algorithm's performance on a range of well-known benchmark test functions, GSA, and its variations is compared. The results of the experiments suggest that the proposed method outperforms the other variants in terms of convergence speed and avoiding local minima; FNNs are being trained.


Assuntos
Algoritmos , Redes Neurais de Computação , Evolução Biológica , Simulação por Computador , Gravitação
10.
Adv Sci (Weinh) ; 9(23): e2201968, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35712771

RESUMO

3D locomotion of magnetic microrobots requires at least one pair of coils per axis and 3D feedback of the position of the microrobot. This results in voluminous systems with high-power usage and a small working space, which require complex and expensive controllers. This study presents a single-coil magneto-electromagnetic system, comprising a parallel robot and coil, capable of precise 3D locomotion control of magnetic millirobots while requiring only feedback of the vertical position of the millirobot. The coil current creates a 2D magnetic trapping point in the horizontal plane, which depends on the position and orientation of the coil and toward which the millirobot moves, eliminating the need for position feedback at such plane. The vertical position of the millirobot is controlled by varying the coil current while receiving feedback from the vertical position of the millirobot. Feedbackless 2D control and 1-axis feedback 3D automatic control of magnetic millirobots are experimentally demonstrated, achieving higher speeds and similar position errors when compared to control systems with 3D position feedback. Furthermore, selective control of two millirobots is demonstrated by matching the region of maximum vertical magnetic force and the targeted millirobot, achieving selective levitation and control of such millirobots.


Assuntos
Robótica , Fenômenos Eletromagnéticos , Retroalimentação , Gravitação , Locomoção , Robótica/métodos
11.
Sci Rep ; 12(1): 10251, 2022 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-35715517

RESUMO

Accurate estimates of global sea-level change from the observations of Altimetry, Argo and Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-on (GRACE-FO) are of great value for investigating the global sea-level budget. In this study, we analyzed the global sea-level change over the period from January 2005 to December 2019 by considering all potential impact factors, i.e. three factors for Altimetry observations (two Altimetry products, ocean bottom deformation (OBD) and glacial isostatic adjustment (GIA)), three factors for Argo observations (four Argo products, salinity product error and deep-ocean steric sea-level change), and seven factors for GRACE/GRACE-FO observations including three official RL06 solutions, five spatial filtering methods, three GIA models, two C20 (degree 2 order 0) products, Geocenter motion, GAD field and global mass conservation. The seven impact factors of GRACE/GRACE-FO observations lead to ninety combinations for the post-procession of global mean barystatic sea-level change estimation, whose rates range from 2.00 to 2.45 mm/year. The total uncertainty of global barystatic sea-level change rate is ± 0.27 mm/year at the 95% confidence level, estimated as the standard deviation of the differences between the different datasets constituting the ensembles. The statistical results show that the preferred GIA model developed by Caron et al. in 2018 can improve the closure of the global sea-level budget by 0.20-0.30 mm/year, which is comparable with that of neglecting the halosteric component. About 30.8% of total combinations (GRACE/GRACE-FO plus Argo) can close the global sea-level budget within 1-sigma (0.23 mm/year) of Altimetry observations, 88.9% within 2-sigma. Once the adopted factors including GRACE/GRACE-FO solutions from Center for Space Research (CSR), Caron18 GIA model, SWENSON filtering and Argo product from China Second Institute of Oceanography, the linear trend of global sterodynamic sea-level change derived from GRACE/GRACE-FO plus Argo observations is 3.85 ± 0.14 mm/year, nearly closed to 3.90 ± 0.23 mm/year of Altimetry observations.


Assuntos
Clima , Oceanografia , China , Gravitação , Oceanografia/métodos , Salinidade
12.
Exp Brain Res ; 240(7-8): 2017-2025, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35716191

RESUMO

This study aimed to test the role of the otolithic system in self-motion perception by examining adaptive responses to asymmetric off-axis vertical rotation. Self-movement perception was examined after a conditioning procedure consisting of prolonged asymmetric sinusoidal yaw rotation of the head on a stationary body with hemicycle faster than the other hemicycle. This asymmetric velocity rotation results in a cumulative error in spatial self-motion perception in the upright position that persists over time. Head yaw rotation conditioning was performed in different head positions: in the upright position to activate semicircular canals and in the supine and prone positions to activate both semicircular canals and otoliths with the phase of otolithic stimulation reversed with respect to activation of the semicircular canals. The asymmetric conditioning influenced the cumulative error induced by four asymmetric cycles of whole-body vertical axis yaw rotation. The magnitude of this error depended on the orientation of the head during the conditioning. The error increased by 50% after upright position conditioning, by 100% in the supine position, and decreased by 30% in the prone position. The enhancement and reduction of the perceptual error are attributed to otolithic modulation because of gravity influence of the otoliths during the conditioning procedure in supine and prone positions. These findings indicate that asymmetric velocity otolithic activation induces adaptive perceptual errors such as those induced by semicircular canals alone, and this adaptation may be useful in testing dynamic otolithic perceptual responses under different conditions of vestibular dysfunction.


Assuntos
Percepção de Movimento , Membrana dos Otólitos , Gravitação , Humanos , Movimento (Física) , Membrana dos Otólitos/fisiologia , Reflexo Vestíbulo-Ocular/fisiologia , Canais Semicirculares/fisiologia
13.
Exp Psychol ; 69(2): 61-74, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35726674

RESUMO

Representational Momentum and Representational Gravity describe systematic perceptual biases, occurring for the localization of the final location of a moving stimulus. While Representational Momentum describes the systematic overestimation along the motion trajectory (forward shift), Representational Gravity refers to a systematic localization bias in line with gravitational force (downward shift). Those phenomena are typically investigated in a laboratory setting, and while previous research has shown that online studies perform well for different task, motion perception outside of the laboratory was not focused to date. Therefore, one experiment was conducted in two different settings: in a typical, highly controlled laboratory setting and in an online setting of the participants' choosing. In both experiments, the two most common trial types, implied motion stimuli and continuously moving stimuli, were used, and the influence of classical velocity manipulations (by varying stimulus timing and distance) was assessed. The data pattern across both experiments was very similar, indicating a robustness of both phenomena and indicating that motion perception can very well be studied outside the classical laboratory setting, opening a feasible possibility to diversify access to motion perception experiments everywhere.


Assuntos
Percepção de Movimento , Viés , Gravitação , Humanos
14.
J Vis Exp ; (183)2022 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-35723485

RESUMO

Gravity sensation is an important and relatively understudied process. Sensing gravity enables animals to navigate their surroundings and facilitates movement. Additionally, gravity sensation, which occurs in the mammalian inner ear, is closely related to hearing - thus, understanding this process has implications for auditory and vestibular research. Gravitaxis assays exist for some model organisms, including Drosophila. Single worms have previously been assayed for their orientation preference as they settle in solution. However, a reliable and robust assay for Caenorhabditis gravitaxis has not been described. The present protocol outlines a procedure for performing gravitaxis assays that can be used to test hundreds of Caenorhabditis dauers at a time. This large-scale, long-distance assay allows for detailed data collection, revealing phenotypes that may be missed on a standard plate-based assay. Dauer movement along the vertical axis is compared with horizontal controls to ensure that directional bias is due to gravity. Gravitactic preference can then be compared between strains or experimental conditions. This method can determine molecular, cellular, and environmental requirements for gravitaxis in worms.


Assuntos
Caenorhabditis , Resposta Táctica , Animais , Gravitação , Sensação Gravitacional , Larva , Mamíferos
15.
Stud Hist Philos Sci ; 94: 72-86, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35665637

RESUMO

Based on string theory's framework, the gauge/gravity duality, also known as holography, has the ability to solve practical problems in low energy physical systems like metals and fluids. Holographic applications open a path for conversation and collaboration between the theory-driven, high energy culture of string theory and fields like nuclear and condensed matter physics, which in contrast place great emphasis on the empirical evidence that experiment provides. This paper takes a look at holography's history, from its roots in string theory to its present-day applications that are challenging the cultural identity of the field. I will focus on two of these applications: holographic QCD and holographic superconductivity, highlighting some of the (often incompatible) historical influences, motives, and epistemic values at play, as well as the subcultural shifts that help the collaborations work. The extent to which holographic research - arguably string theory's most successful and prolific area - must change its subcultural identity in order to function in fields outside of string theory reflects its changing nature and the uncertain future of the field. Does string theory lose its identity in the low-energy applications that holography provides? Does holography still belong under string theory's umbrella, or is it destined to form new subcultures with each of its fields of application? I find that the answers to these questions are dynamic, interconnected, and highly dependent on string theory's relationship with its field of application. In some cases, holography can maintain the goals and values it inherited from string theory. In others, it instead adopts the goals and values of the field in which it is applied. These examples highlight a growing need for the STS community to expand its treatment of string theory regarding its relationship with empiricism and role as a theory of quantum gravity.1.


Assuntos
Holografia , Empirismo , Gravitação , Física
16.
J Biomech ; 138: 111114, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35576633

RESUMO

Humans can quickly adapt to different task demands in cycling. The motor system continuously manipulates applied pedal forces under the influence of gravitational and inertial forces, but the muscular control strategy remains unknown. The aim of this study was to investigate muscular control and coordination when altering pedal force patterns, using a musculoskeletal model with dynamic tracking optimization and induced acceleration analysis (IAA). The tracking data were pedaling kinematics and kinetics in recreational cyclists before and after learning to apply pedal force toward a tangential target direction in one-legged pedaling (Park et al., 2021). The gravity and inertial force contributions to pedal forces were relatively unchanged after practice due to the consistent rider posture and pedaling mechanics. Pedal force contributions induced by individual muscle-tendon units (MTUs) were also relatively consistent in direction before and after practice, likely due to similar joint positions and task constraints in the two conditions. However, the total applied pedal force from the sum of IAA component contributions was more closely directed towards the target due to coordinated changes in the magnitudes of contributions of the resultant pedal force by individual MTUs. The improvement in pedal force targeting seen in this complex coordination task may be possible through a control strategy of scaling muscle activity level. The rapid adaptation to a new pedal force pattern in this constrained task is facilitated by a relatively simple strategy of scaling muscle activation amplitude.


Assuntos
, Músculo Esquelético , Ciclismo/fisiologia , Fenômenos Biomecânicos , Pé/fisiologia , Gravitação , Humanos , Músculo Esquelético/fisiologia
17.
Physiol Rep ; 10(10): e15289, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35586957

RESUMO

The lymphatic system is compromised in different groups of patients. To recognize pathology, we must know what is healthy. We use Near-Infrared Fluorescence (NIRF) to assess peripheral lymphatic function in humans. We have shown that external factors such as exercise, hyperthermia, and pharmacological mediators influence the function of peripheral lymphatic vessels. In this study, we explored the impact on lymphatic vessels by the ever-present external factor-gravity. We used NIRF imaging to investigate the lymphatic changes to gravity. Gravity was assessed by changing body position from supine to standing. We extracted following lymphatic functional parameters: lymphatic packet propulsion frequency (contractions/min), velocity (cm/s), and pressure (mmHg). Raw data analysis was performed using a custom-written Labview program. All sequences were analyzed by two observers and interclass correlation scores were calculated. All statistical analysis was performed using RStudio Team (2021). RStudio: Integrated Development Environment for R. RStudio, PBC. Healthy participants (n = 17, 11 males, age 28.1 ± 2.6 years) were included. The lymphatic packet propulsion frequency at baseline was 0.5 ± 0.2 contractions/min and rose within 3 min significantly to a maximum of 1.2 ± 0.5 contractions/min during upright posture and remained significantly higher than the baseline lymphatic packet propulsion frequency after lying down again for up to 6 min. The lymph velocity was 1.5 ± 0.4 cm/s at baseline and changed in both directions and without a specific pattern at different points in time during standing. Lymph pressure was significantly higher while standing (mean increase 9 mmHg, CI: 2-15 mmHg). The ICC scores were 89.8% (85.9%-92.7%), 59.3% (46.6%-69.6%) and 89.4% (79.0%-94.8%) in lymphatic packet propulsion frequency (130 observations), velocity (125 observations), and pressure (30 observations), respectively. The lymphatic system responds within few minutes to gravitational changes by increasing lymphatic packet propulsion frequency and pressure.


Assuntos
Vasos Linfáticos , Adulto , Gravitação , Humanos , Linfa , Masculino , Imagem Óptica , Postura
18.
Sci Rep ; 12(1): 8023, 2022 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-35577830

RESUMO

Although lung involvement in aspiration pneumonia typically has a gravity-dependent distribution on chest images, which patient's conditions contribute to its radiological pattern has not been fully elucidated. This study was designed to determine the factors associated with the gravity-dependent distribution of community-acquired pneumonia (CAP) on chest computed tomography (CT). This retrospective study included elderly patients aged ≥ 65 years with CAP who underwent chest CT within 1 week before or after admission. The factors associated with lower lobe- and posterior-predominant distributions of ground glass opacity or airspace consolidation were determined. Of the 369 patients with CAP, 348 (94%) underwent chest CT. Multivariate analyses showed that impaired consciousness, a low Barthel index of activities of daily living, and high hemoglobin levels were associated with lower lobe-predominant distribution, while male sex and impaired consciousness were associated with posterior-predominant distribution. Cerebrovascular diseases were unrelated to these distributions. While male sex, impaired consciousness, high hemoglobin levels, low albumin levels, and the number of involved lobes were associated with in-hospital mortality, gravity-dependent distributions were not. Impaired consciousness might be the most significant predictor of aspiration pneumonia; however, the gravity-dependent distribution of this disease is unlikely to affect disease prognosis.


Assuntos
Infecções Comunitárias Adquiridas , Pneumonia Aspirativa , Pneumonia , Atividades Cotidianas , Idoso , Infecções Comunitárias Adquiridas/diagnóstico por imagem , Gravitação , Hemoglobinas , Humanos , Pulmão , Masculino , Pneumonia/diagnóstico por imagem , Pneumonia Aspirativa/diagnóstico por imagem , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos
19.
Nat Commun ; 13(1): 2765, 2022 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-35589705

RESUMO

The human visual perceptual system is highly sensitive to biological motion (BM) but less sensitive to its inverted counterpart. This perceptual inversion effect may stem from our selective sensitivity to gravity-constrained life motion signals and confer an adaptive advantage to creatures living on Earth. However, to what extent and how such selective sensitivity is shaped by the Earth's gravitational field is heretofore unexplored. Taking advantage of a spaceflight experiment and its ground-based analog via 6° head-down tilt bed rest (HDTBR), we show that prolonged microgravity/HDTBR reduces the inversion effect in BM perception. No such change occurs for face perception, highlighting the particular role of gravity in regulating kinematic motion analysis. Moreover, the reduced BM inversion effect is associated with attenuated orientation-dependent neural responses to BM rather than general motion cues and correlated with strengthened functional connectivity between cortical regions dedicated to visual BM processing (i.e., pSTS) and vestibular gravity estimation (i.e., insula). These findings suggest that the neural computation of gravity may act as an embodied constraint, presumably implemented through visuo-vestibular interaction, to sustain the human brain's selective tuning to life motion signals.


Assuntos
Percepção de Movimento , Vestíbulo do Labirinto , Gravitação , Humanos , Movimento (Física) , Percepção de Movimento/fisiologia , Vestíbulo do Labirinto/fisiologia , Percepção Visual
20.
Sensors (Basel) ; 22(9)2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35591188

RESUMO

Whole-body center of gravity (CG) movements in relation to the center of pressure (COP) offer insights into the balance control strategies of the human body. Existing CG measurement methods using expensive measurement equipment fixed in a laboratory environment are not intended for continuous monitoring. The development of wireless sensing technology makes it possible to expand the measurement in daily life. The insole system is a wearable device that can evaluate human balance ability by measuring pressure distribution on the ground. In this study, a novel protocol (data preparation and model training) for estimating the 3-axis CG trajectory from vertical plantar pressures was proposed and its performance was evaluated. Input and target data were obtained through gait experiments conducted on 15 adult and 15 elderly males using a self-made insole prototype and optical motion capture system. One gait cycle was divided into four semantic phases. Features specified for each phase were extracted and the CG trajectory was predicted using a bi-directional long short-term memory (Bi-LSTM) network. The performance of the proposed CG prediction model was evaluated by a comparative study with four prediction models having no gait phase segmentation. The CG trajectory calculated with the optoelectronic system was used as a golden standard. The relative root mean square error of the proposed model on the 3-axis of anterior/posterior, medial/lateral, and proximal/distal showed the best prediction performance, with 2.12%, 12.97%, and 12.47%. Biomechanical analysis of two healthy male groups was conducted. A statistically significant difference between CG trajectories of the two groups was shown in the proposed model. Large CG sway of the medial/lateral axis trajectory and CG fall of the proximal/distal axis trajectory is shown in the old group. The protocol proposed in this study is a basic step to have gait analysis in daily life. It is expected to be utilized as a key element for clinical applications.


Assuntos
Sapatos , Dispositivos Eletrônicos Vestíveis , Adulto , Idoso , Fenômenos Biomecânicos , Marcha , Gravitação , Humanos , Aprendizado de Máquina , Masculino
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