Search Results (8)

Mental activity is capable of processing analytical data (mathematics, physics, socio-political science, philosophy, etc.) similar to computer software. At the same time, mental activity largely depends on the brain, which works like a hard component of a computer. While the computer stores data on a physical medium, mental activity and data are supported by physiological mechanisms that are constantly operating (both in wakefulness and sleep). For this reason, the lack of brain oxygenation even for short periods of time (5–10 minutes) causes the loss of all data, including the disappearance of the individual's existence as a mental entity. This means that psycho-physiological mechanisms that run continuously can accumulate malfunctions, but also that they can be interfered with, for example by coffee. We have presented in previous articles the similarity between computer operation and mental activity. This brief review is a synthesis of published articles and, at the same time, a preamble to an SSRI-based pharmacological approach capable of resetting mental activity (by restoring mental patterning) but without interrupting, losing or altering existing mental data. Full article

Gout is at least three times more prevalent in males than in females. However, concurrent with rising total gout prevalence, complex factors, including comorbidities, diet, lifestyle, and aging, have promoted higher gout prevalence in females. This narrative review focuses on summarizing recent developments in the landscape of gout in females and the mechanisms involved. New knowledge on sex hormone effects on both urate-excreting and urate-reabsorbing transporters and higher hypertension and chronic kidney disease prevalence in females compared to males may help explain why gout incidence rises robustly after menopause in females, to approach that in males. Racial and ethnic factors, risk profiles based on heritable genetic polymorphisms of urate transporters, diet, body mass index, and lifestyle factors differ according to sex. In addition, sex differences in clinical phenotypes, outcomes of gout, and non-gout illnesses include more frequent comorbidities, more pain and disability during gout flares, different perceptions of disease burden, and more frequent severe cutaneous hypersensitivity reaction to allopurinol in females. Collectively, such findings support the potential clinical benefits of tailoring gout and hyperuricemia treatment according to sex. Full article

Micromechanical switches are of significant interest for advanced radio frequency and microwave systems, but their practical implementation is limited by low reliability. Electrodes of a microscopic size develop weak contact force that leads to high and unstable contact resistance. The force is typically increased by using a sophisticated switch design with extended lateral dimensions, although a simple and compact cantilever is more preferable. The paper describes for the first time a comprehensive approach to enhance the force of an electrostatically actuated switch. The strategy is applied to a miniature device based on a 50 µm long cantilever. The contact force is increased from 10 to 112 µN, making the switch strong enough to achieve low and stable contact resistance. The restoring force is also enhanced in order to ensure reliable de-actuation. The growth of forces is accompanied by a reduction in the pull-in voltage. Connecting several cantilevers in parallel and manipulating the number and position of contact bumps additionally improves the force and mechanical stability of the switch. An optimal design contains a triple cantilever with two bumps. It provides 50% higher force per contact compared to the single-cantilever switch at the same pull-in voltage and keeps the advantages of a miniature device. The proposed design strategy may be used for building reliable MEMS switches. Full article

This paper proposes an efficient hybrid analytical-computational approach for the simulation of mechanical vibrations and sound radiation in wind turbine drive trains.The computational procedure encompasses the detailed modeling of vibrational sources and structural sound paths as well as the major panels of airborne noise radiation. The angle-varying mesh stiffness is obtained from a series of quasi-static finite element simulations. A novel procedure is proposed to obtain the time-varying mesh stiffness at fluctuating speed. The varying mesh stiffness is introduced as a parametric excitation in an analytical gear model, and the Fourier-transformed results are used as vibrational sources in a finite-element-based harmonic response analysis of the drive train. The present paper focuses on the modeling of gear contact and gearbox vibrations. The models and procedures are outlined, and computational results are compared to physical measurements on a 2.5 MW wind turbine. The results are in good qualitative agreement at tonal frequencies. This is particularly the case at fluctuating speed, where both the simulation and the measurement show the characteristic effect of frequency modulation. The computational procedure has been expanded to the whole drive train and is effectively applied in the conception and evaluation of design measures for the reduction of tonal amplitudes. Full article

Purpose: Mental practice using motor imagery (MP) improves motor strength and coordination in the upper and lower extremities in clinical patient populations. Its effectiveness as a rehabilitation tool for patients with lingual weakness is not yet well understood, nor are the underlying mechanisms within the context of swallow or lingual MP. Using previously published data on a lingual and MP exercise program, the objective of this study was to explore how MP of lingual exercise affects cortical activation in healthy older adults over time and how neural changes correlate with functional oral pressure outcomes. Method: A prospective randomized controlled study was previously completed; older healthy participants were randomized to one of four treatment groups receiving lingual MP, lingual physical practice, a combination of both, and a sham control. This paper reports descriptive data on cortical activation during both the physical and mental forms of lingual resistance in a subgroup of 13 participants using functional near-infrared spectroscopy at baseline and after 6 weeks of the assigned exercise regimen. Results: Aggregated data indicates that participants who completed 6 weeks of lingual exercise, either in physical or in MP form, had decreased oxygenated hemoglobin when completing a maximal lingual pressure task. Conclusions: Some participants in a lingual resistance MP program demonstrated trends similar to those seen after strength training. Combining MP with physical training may lead to greater changes in oxygenation compared to a physical or mental training program alone, although given the small number of participants, it is important not to overinterpret the results. MP is a promising, innovative approach that may enhance traditional exercise-based swallowing rehabilitation. Full article

This paper presents the concept of muscle-driven locomotion for planar snake robots, which combines the advantages of both rigid and soft robotic approaches to enhance the performance of snake robot locomotion. For this purpose, two adjacent links are connected by a pair of pneumatic artificial muscles wherein an alternate actuation of these soft actuators causes a rotational motion at the connecting joints. The muscle-based actuated linkage mechanism, as a closed six-linkage mechanism, was designed and prototyped. The linear motion and force generation of the pneumatic artificial muscle was experimentally characterized using isotonic and isometric contraction experiments. A predictive model was developed based on the experimental data to describe the relationship between the force–length–pressure of the PAMs. Additionally, the muscle-driven mechanism was kinematically and dynamically characterized based on both theoretical and experimental studies. The experimental data generally agreed with our model’s results and the generated joint angle and torque were comparable to the current snake-like robots. A skx-link planar snake robot with five joints, five pairs of antagonistic muscles, and an associated pneumatic controller was prototyped and examined for simple movements on a straight-line. We demonstrated the muscle-driven locomotion of the six-link snake robot, and the results show the feasibility of using the proposed mechanism for future explorations of snake robot locomotion. Full article

The complex nature of the damage evolution in stress corrosion cracking (SCC) leads to explore for new investigation technologies in order to better identify the mechanisms that supervise the initiation and evolution of the damage as well to provide an improvement of knowledge on this critical localized corrosion form during time. Research activities concerning the use of acoustic emission (AE) technique to assess SCC has acquiring considerably relevance in recent decades. The non-invasiveness and the possibility to provide a continuous in situ monitoring of structures and components make this non-destructive technique clearly promising in the field of structural health monitoring. In this concern, this paper aims to be a focused overview on the evaluation of SCC phenomena by AE technique. The main topic of this review is centered on the approaches that can be used in elaborating AE data to better discriminate the mechanisms that contribute to damage propagation in SCC conditions. Based on available literature, investigation approaches assessing AE waveform parameters were classified, evidencing, furthermore, the identified mechanisms that synergistically take place during the material degradation. Eventually, a brief summary and a future trend evaluation was also reported. Full article

Organizational agility is a key factor for survival and success in today’s global, interconnected and turbulent business environment. Mobile technology, due to its anywhere, anytime characteristics, can be a promising tool for enhancing organizational agility. Yet there are no studies that guide organizations in leveraging mobile technology for improving speed and responsiveness to market needs. This paper attempts to fill this gap by exploring the question of how mobile technology can be used to enhance organizational agility. We use an exploratory research approach that analyzes archival data of 89 case studies describing contemporary applications of mobile technology within organizations. After developing a mobile agility framework and using it as our analytical lens, we examine each case to identify specific ways in which mobile technology is used to improve operational, customer, and partnering agility. The main contribution of this study is identification of emergent clusters of agility-enhancing mechanisms based on the benefits of mobile technology. The discovered benefits and mechanisms can guide organizations on improving their agility with the help of mobile technology. We also formulate research questions that should be addressed by future studies in order to produce a more comprehensive theoretical understanding of how mobile technology improves organizational agility. Full article