scholarly journals Effects of Local Gravity Compensation on Motor Control During Altered Environmental Gravity

2021 ◽  
Vol 15 ◽  
Author(s):  
Tjasa Kunavar ◽  
Marko Jamšek ◽  
Marie Barbiero ◽  
Gunnar Blohm ◽  
Daichi Nozaki ◽  
...  

Our sensorimotor control is well adapted to normogravity environment encountered on Earth and any change in gravity significantly disturbs our movement. In order to produce appropriate motor commands for aimed arm movements such as pointing or reaching, environmental changes have to be taken into account. This adaptation is crucial when performing successful movements during microgravity and hypergravity conditions. To mitigate the effects of changing gravitational levels, such as the changed movement duration and decreased accuracy, we explored the possible beneficial effects of gravity compensation on movement. Local gravity compensation was achieved using a motorized robotic device capable of applying precise forces to the subject’s wrist that generated a normogravity equivalent torque at the shoulder joint during periods of microgravity and hypergravity. The efficiency of the local gravity compensation was assessed with an experiment in which participants performed a series of pointing movements toward the target on a screen during a parabolic flight. We compared movement duration, accuracy, movement trajectory, and muscle activations of movements during periods of microgravity and hypergravity with conditions when local gravity compensation was provided. The use of local gravity compensation at the arm mitigated the changes in movement duration, accuracy, and muscle activity. Our results suggest that the use of such an assistive device helps with movements during unfamiliar environmental gravity.

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 682
Author(s):  
Serena Coppola ◽  
Carmen Avagliano ◽  
Antonio Calignano ◽  
Roberto Berni Canani

Worldwide obesity is a public health concern that has reached pandemic levels. Obesity is the major predisposing factor to comorbidities, including type 2 diabetes, cardiovascular diseases, dyslipidemia, and non-alcoholic fatty liver disease. The common forms of obesity are multifactorial and derive from a complex interplay of environmental changes and the individual genetic predisposition. Increasing evidence suggest a pivotal role played by alterations of gut microbiota (GM) that could represent the causative link between environmental factors and onset of obesity. The beneficial effects of GM are mainly mediated by the secretion of various metabolites. Short-chain fatty acids (SCFAs) acetate, propionate and butyrate are small organic metabolites produced by fermentation of dietary fibers and resistant starch with vast beneficial effects in energy metabolism, intestinal homeostasis and immune responses regulation. An aberrant production of SCFAs has emerged in obesity and metabolic diseases. Among SCFAs, butyrate emerged because it might have a potential in alleviating obesity and related comorbidities. Here we reviewed the preclinical and clinical data that contribute to explain the role of butyrate in this context, highlighting its crucial contribute in the diet-GM-host health axis.


Author(s):  
Irina Sokolik

There is scientific consensus that human activities have been altering the atmospheric composition and are a key driver of global climate and environmental changes since pre-industrial times (IPCC, 2013). It is a pressing priority to understand the Earth system response to atmospheric aerosol input from diverse sources, which so far remain one of the largest uncertainties in climate studies (Boucher et al., 2014; Forster et al., 2007). As the second most abundant component (in terms of mass) of atmospheric aerosols, mineral dust exerts tremendous impacts on Earth’s climate and environment through various interaction and feedback processes. Dust can also have beneficial effects where it deposits: Central and South American rain forests get most of their mineral nutrients from the Sahara; iron-poor ocean regions get iron; and dust in Hawaii increases plantain growth. In northern China as well as the midwestern United States, ancient dust storm deposits known as loess are highly fertile soils, but they are also a significant source of contemporary dust storms when soil-securing vegetation is disturbed. Accurate assessments of dust emission are of great importance to improvements in quantifying the diverse dust impacts.


Pathogens ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 80 ◽  
Author(s):  
Pilar Somovilla ◽  
Susanna Manrubia ◽  
Ester Lázaro

The rate of change in selective pressures is one of the main factors that determines the likelihood that populations can adapt to stress conditions. Generally, the reduction in the population size that accompanies abrupt environmental changes makes it difficult to generate and select adaptive mutations. However, in systems with high genetic diversity, as happens in RNA viruses, mutations with beneficial effects under new conditions can already be present in the population, facilitating adaptation. In this work, we have propagated an RNA bacteriophage (Qβ) at temperatures higher than the optimum, following different patterns of change. We have determined the fitness values and the consensus sequences of all lineages throughout the evolutionary process in order to establish correspondences between fitness variations and adaptive pathways. Our results show that populations subjected to a sudden temperature change gain fitness and fix mutations faster than those subjected to gradual changes, differing also in the particular selected mutations. The life-history of populations prior to the environmental change has great importance in the dynamics of adaptation. The conclusion is that in the bacteriophage Qβ, the standing genetic diversity together with the rate of temperature change determine both the rapidity of adaptation and the followed evolutionary pathways.


2020 ◽  
Vol 96 (8) ◽  
Author(s):  
Clément Offret ◽  
Sauvann Paulino ◽  
Olivier Gauthier ◽  
Kevin Château ◽  
Adeline Bidault ◽  
...  

ABSTRACT Digestive microbiota provide a wide range of beneficial effects on host physiology and are therefore likely to play a key role in marine intertidal bivalve ability to acclimatize to the intertidal zone. This study investigated the effect of intertidal levels on the digestive bacterial microbiota of oysters (Crassostrea gigas) and clams (Ruditapes philippinarum), two bivalves with different ecological niches. Based on 16S rRNA region sequencing, digestive glands, seawater and sediments harbored specific bacterial communities, dominated by operational taxonomic units assigned to the Mycoplasmatales,Desulfobacterales and Rhodobacterales orders, respectively. Field implantation modified digestive bacterial microbiota of both bivalve species according to their intertidal position. Rhodospirillales and Legionellales abundances increased in oysters and clams from the low intertidal level, respectively. After a 14-day depuration process, these effects were still observed, especially for clams, while digestive bacterial microbiota of oysters were subjected to more short-term environmental changes. Nevertheless, 3.5 months stay on an intertidal zone was enough to leave an environmental footprint on the digestive bacterial microbiota, suggesting the existence of autochthonous bivalve bacteria. When comparing clams from the three intertidal levels, 20% of the bacterial assemblage was shared among the levels and it was dominated by an operational taxonomic unit affiliated to the Mycoplasmataceae and Spirochaetaceae families.


2020 ◽  
Vol 32 (1) ◽  
pp. 138-148
Author(s):  
Yasuyuki Yamada ◽  
Hirokazu Arakawa ◽  
Taro Watanabe ◽  
Shunya Fukuyama ◽  
Rie Nishihama ◽  
...  

During overhead work, workers need to keep raising weights of approximately 2 to 4 kg with the muscular strength of their upper limbs, and the burden of this work is high. Therefore, we developed an assistive device, named TasKi, using a self-weighted compensation mechanism to reduce the burden on upper limbs during overhead work. It can compensate for upper limb weight using the force of a spring in various postures of the upper limbs, without a battery. In this study, to provide effective assistance to many users, we clarified the crucial assistance and parameter adjustment range of settings corresponding to physical differences. First, the assistive force value of TasKi to reduce the work burden of each user was confirmed via a subjective evaluation experiment and myoelectric potential measurements. Next, we conducted a test survey of TasKi users and investigated the relationship between physique and the wearing feeling. According to the survey, 80% of the subjects provided favorable opinions on the assistive method used by TasKi. Finally, we had subjects of various physiques wear the device and investigated the relationship between physique and the wearing feeling with respect to shoulder joint movements. It was observed that the subjects with greater shoulder widths experienced difficulties when moving in the direction of internal-external rotation because of the small size of TasKi. The influence on the ease of motion and perception of size was less in the direction of flexion-extension and adduction-abduction motions.


1999 ◽  
Vol 13 (2) ◽  
pp. 77-81 ◽  
Author(s):  
Yani Chen ◽  
Shigeo Mori ◽  
Kazuo Koga ◽  
Yoshihiro Ohta ◽  
Yoshiro Wada ◽  
...  

2009 ◽  
Vol 102 (2) ◽  
pp. 786-796 ◽  
Author(s):  
Frédéric Crevecoeur ◽  
Jean-Louis Thonnard ◽  
Philippe Lefèvre

The planning and control of motor actions requires knowledge of the dynamics of the controlled limb to generate the appropriate muscular commands and achieve the desired goal. Such planning and control imply that the CNS must be able to deal with forces and constraints acting on the limb, such as the omnipresent force of gravity. The present study investigates the effect of hypergravity induced by parabolic flights on the trajectory of vertical pointing movements to test the hypothesis that motor commands are optimized with respect to the effect of gravity on the limb. Subjects performed vertical pointing movements in normal gravity and hypergravity. We use a model based on optimal control to identify the role played by gravity in the optimal arm trajectory with minimal motor costs. First, the simulations in normal gravity reproduce the asymmetry in the velocity profiles (the velocity reaches its maximum before half of the movement duration), which typically characterizes the vertical pointing movements performed on Earth, whereas the horizontal movements present symmetrical velocity profiles. Second, according to the simulations, the optimal trajectory in hypergravity should present an increase in the peak acceleration and peak velocity despite the increase in the arm weight. In agreement with these predictions, the subjects performed faster movements in hypergravity with significant increases in the peak acceleration and peak velocity, which were accompanied by a significant decrease in the movement duration. This suggests that movement kinematics change in response to an increase in gravity, which is consistent with the hypothesis that motor commands are optimized and the action of gravity on the limb is taken into account. The results provide evidence for an internal representation of gravity in the central planning process and further suggest that an adaptation to altered dynamics can be understood as a reoptimization process.


Author(s):  
Velmurugan Devadass ◽  
Pachiappan Raman ◽  
D. Gayathri

Introduction: In both developing and developed countries, cancer is among the leading causes of millions of deaths. The incidence of cancer is increasing due to environmental changes and modernization of life style. Lung and breast cancer deaths lead in number compared to other cancer deaths. Although the cause of cancer due to external factors like tobacco use, chemicals, radiation, infectious organisms and internal factors like immune conditions and genetic modification are known, the occurrence and deaths due to cancer cannot be controlled. Methods: It is expected that the incidence of cancer after two decades will increase by 70% and death rate will also increase by 50%, which is an alarming situation globally. Although synthetic compounds are being used in the control of cancer as chemopreventive agents, about 50% of these are related to natural products as the origin. There is an emerging evidence to show that in the past 50 years, natural products derived from plants and marine sources had beneficial effects in the treatment and prevention of cancer. Taxol, vincristine, vinblastine, cytarabine, eribulin mesylate and trabectidine are some of the anticancer compounds isolated from terrestrial and marine sources. Results: This review highlights mainly the role of natural compounds isolated from terrestrial and marine sources as anticancer agents through the docking of these compounds with the related macromolecular targets. Conclusion: Cell line studies for some of the compounds isolated from natural products are also reported.


2018 ◽  
Vol 72 (7) ◽  
pp. 1756-1770 ◽  
Author(s):  
Paul AG Forbes ◽  
Steph F Suddell ◽  
Harry Farmer ◽  
Yanakan Logeswaran ◽  
Antonia F de C Hamilton

Whether pointing at a menu item or rifling through a clothes rack, when we choose we often move. We investigated whether people’s tendency to copy the movements of others could influence their choices. Participants saw pairs of pictures in private and indicated which one they preferred. They then entered a virtual art gallery and saw the same picture pairs in the presence of a virtual character. Having observed the virtual character point to indicate her preference with either a high or low movement trajectory, participants indicated their preference. There was either an anatomical (same movement, same choice) or spatial correspondence (same movement, different choice) between the participant’s pictures and those of the virtual character. We found that participants copied the movement made by the virtual character rather than her action goal (i.e., her choice of picture). This resulted in a shift towards the virtual character’s preferences in the anatomical condition but away from her preferences in the spatial condition. This effect was driven by the observation of the virtual character’s high pointing movements. In a further experiment, we did not find any significant differences in imitation behaviour in autism, although autistic participants were less consistent in their choices. Our findings demonstrate that we are not only influenced by other’s choices but also the types of movements others make to indicate those choices.


Sign in / Sign up

Export Citation Format

Share Document