What Is the Readiness Potential? Schurger, Aaron; Hu, Pengbo 'Ben'; Pak, Joanna ...
Trends in cognitive sciences,
07/2021, Letnik:
25, Številka:
7
Journal Article
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The readiness potential (RP), a slow buildup of electrical potential recorded at the scalp using electroencephalography, has been associated with neural activity involved in movement preparation. It ...became famous thanks to Benjamin Libet (Brain 1983;106:623–642), who used the time difference between the RP and self-reported time of conscious intention to move to argue that we lack free will. The RP’s informativeness about self-generated action and derivatively about free will has prompted continued research on this neural phenomenon. Here, we argue that recent advances in our understanding of the RP, including computational modeling of the phenomenon, call for a reassessment of its relevance for understanding volition and the philosophical problem of free will.
The readiness potential (RP) has been widely interpreted to indicate preparation for movement and is used to argue that our brains decide before we do. It thus has been a fulcrum for discussion about the neuroscience of free will.Recent computational models provide an alternative framework for thinking about the significance of the RP, suggesting instead that the RP is a natural result of the operation of a stochastic accumulator process of decision-making, analyzed by time-locking to threshold-crossing events.These models call for a reevaluation of: (i) the ontological standing of the RP as reflecting a real, causally efficacious signal in the brain; (ii) the meaningfulness of temporal comparisons between the ‘onset’ of the RP and the timing of other phenomena; (iii) the moment at which we, as experimenters, identify that a decision to act has been made; and (iv) the relevance of the RP for discussions of free will.
Three thiadiazoloquinoxaline‐containing long pyrene‐fused N‐heteroacenes with 8, 13, and 18 rings were designed and synthesized. They show high electron affinities (EAs) of approximately 4.1 eV, ...which were derived from the onset of the reduction peaks in cyclic voltammetry. Crystal structure analysis revealed in‐plane extension through close contacts between thiadiazole units as well as layered packing, enabling in‐plane and interlayer electron transport. Organic field‐effect transistor devices provided electron mobilities, which suggest a potential way to enhance the charge transport in long N‐heteroacenes.
Layered packing: Long pyrene‐fused heteroacenes with 8, 13, and 18 rings were designed and synthesized. They show high electron affinities, layered packing in the crystals, and enhanced in‐plane electron transport.
Recently, the development of polycyclic aromatic hydrocarbon (PAH)‐based organic co‐crystals has attracted increasing interest due to their unique packing modes, optic‐electronic properties and ...various potential applications in electronic, optic‐electronic and magnetic devices. In this account, we mainly discuss the definition, classification, packing patterns, preparation methods, and applications of PAH‐based co‐crystals. Specifically, the main categories of PAH‐based organic co‐crystals, the frequent methods to prepare them, three main packing patterns, their optical and electrical properties, and their potential applications will be presented. Finally, an outlook of this field is provided.
This account will briefly discuss the definition, classification, packing patterns, preparation methods and the applications of polycyclic aromatic hydrocarbon (PAH)‐based co‐crystals.
High‐dielectric‐constant elastomers always play a critical role in the development of wearable electronics for actuation, energy storage, and sensing; therefore, there is an urgent need for effective ...strategies to enhance dielectric constants. The present methods mainly involve adding inorganic or conductive fillers to the polymer elastomers, however, the addition of fillers causes a series of problems, such as large dielectric loss, increased modulus, and deteriorating interface conditions. Here, the elastification of relaxor ferroelectric polymers is investigated through slight cross‐linking, aiming to obtain intrinsic elastomers with high‐dielectric constants. By cross‐linking of the relaxor ferroelectric polymer poly(vinylidene fluoride‐ter‐trifluoroethylene‐ter‐chlorofluoroethylene) with a long soft chain cross‐linker, a relaxor ferroelectric elastomer with an enhanced dielectric constant is obtained, twice that of the pristine relaxor ferroelectric polymer and surpassing all reported intrinsic elastomers. This elastomer maintains its high‐dielectric constant over a wide temperature range and exhibits robust mechanical fatigue resistance, chemical stability, and thermal stability. Moreover, the ferroelectricity of the elastomer remains stable under strains up to 80%. This study offers a simple and effective way to enhance the dielectric constant of intrinsic elastomers, thus facilitating advancements in soft robots, biosensors, and wearable electronics.
Through the slight cross‐linking of relaxor ferroelectric poly(vinylidene fluoride‐ter‐trifluoroethylene‐ter‐chlorofluoroethylene) (P(VDF‐TrFE‐CFE)), intrinsic elastomer with a remarkable dielectric constant of 54.2 at 100 Hz is obtained. Notably, the dielectric constant of the elastomer nearly doubles that of pristine P)(VDF‐TrFE‐CFE), and surpasses all reported intrinsic elastomers, suggesting that the slight cross‐linking of relaxor ferroelectric polymers can effectively enhance the dielectric constants in intrinsic elastomers.
In the past decade, the self-healing elastomers based on multiple hydrogen bonding have attracted ample attention due to their rich chemical structures, adjustable mechanical properties, fast healing ...speed, and high healing efficiency. Through prolonging the service life and fast recovery of the mechanical properties, self-healing elastomers can be potentially applied in the field of wearable electronics, electronic skins, motion tracking, and health monitoring. In this perspective, we will introduce the concept and classification of self-healing materials first, then the hydrogen bonds, and the corresponding position of hydrogen-bonding units in the polymer structures. We will also conclude the potential application of hydrogen bonding-based elastomers. Finally, a summary and outlook will be provided.
As ferroelectrics hold significance and application prospects in wearable devices, the elastification of ferroelectrics becomes more and more important. Nevertheless, achieving elastic ferroelectrics ...requires stringent synthesis conditions, while the elastification of relaxor ferroelectric materials remains unexplored, presenting an untapped potential for utilization in energy storage and actuation for wearable electronics. The thiol‐ene click reaction offers a mild and rapid reaction platform to prepare functional polymers. Therefore, we employed this approach to obtain an elastic relaxor ferroelectric by crosslinking an intramolecular carbon‐carbon double bonds (CF=CH) polymer matrix with multiple thiol groups via a thiol‐ene click reaction. The resulting elastic relaxor ferroelectric demonstrates pronounced relaxor‐type ferroelectric behaviour. This material exhibits low modulus, excellent resilience, and fatigue resistance, maintaining a stable ferroelectric response even under strains up to 70 %. This study introduces a straightforward and efficient approach for the construction of elastic relaxor ferroelectrics, thereby expanding the application possibilities in wearable electronics.
Relaxor ferroelectrics possess unique advantages, such as high electric‐mechanical responsiveness and high sensitivity to changes in electric fields, which can be potentially employed as the energy storage and actuation in wearable electronics. Herein, we propose a novel approach utilizing thiol‐ene click reaction to develop elastic relaxor ferroelectrics, which is under a mild condition and a compatible procedure with photolithography.
Nanogel-based nanoplatforms have become a tremendously promising system of drug delivery. Nanogels constructed by chemical crosslinking or physical self-assembly exhibit the ability to encapsulate ...hydrophilic or hydrophobic therapeutics, including but not limited to small-molecule compounds and proteins, DNA/RNA sequences, and even ultrasmall nanoparticles, within their 3D polymer network. The nanosized nature of the carriers endows them with a specific surface area and inner space, increasing the stability of loaded drugs and prolonging their circulation time. Reactions or the cleavage of chemical bonds in the structure of drug-loaded nanogels have been shown to trigger the controlled or sustained drug release. Through the design of specific chemical structures and different methods of production, nanogels can realize diverse responsiveness (temperature-sensitive, pH-sensitive and redox-sensitive), and enable the stimuli-responsive release of drugs in the microenvironments of various diseases. To improve therapeutic outcomes and increase the precision of therapy, nanogels can be modified by specific ligands to achieve active targeting and enhance the drug accumulation in disease sites. Moreover, the biomembrane-camouflaged nanogels exhibit additional intelligent targeted delivery features. Consequently, the targeted delivery of therapeutic agents, as well as the combinational therapy strategy, result in the improved efficacy of disease treatments, though the introduction of a multifunctional nanogel-based drug delivery system.
Whether Klotho plays any role in hypothyroidism is unknown. This study aimed to determine the relationship between serum Klotho levels and hypothyroidism in older adults. From the 2007 to 2012 ...National Health and Nutrition Examination Survey (NHANES), 1444 older adults aged 65-79 were included in this cross-sectional study. Hypothyroidism was diagnosed using participants' reports of current medications and TSH tests. Klotho was measured using an enzyme-linked immunosorbent assay. The relationship between serum Klotho levels and hypothyroidism in older people was analyzed by one-way analysis of variance, multiple linear regression models, subgroup analyses, interaction tests, smoothed curve fitting, and threshold effects. A total of 209 (14.47%) participants were identified as having hypothyroidism. Serum Klotho (ln transformation) is independently and significantly negatively associated with the risk of hypothyroidism after complete adjustment for confounders (OR = 0.49, 95% CI 0.31-0.80; P = 0.0039). The results remained stable based on subgroup analyses and interaction tests. However, we observed an inverted U-shaped curve between the two using a smoothed curve fitting in the subgroups of 70 < age ≤ 75 years and females, with inflection points of 6.26 and 6.17, respectively. The results of our study indicate that serum Klotho levels negatively correlate with hypothyroidism among older adults.
Bats are presumed reservoirs of diverse coronaviruses (CoVs) including progenitors of Severe Acute Respiratory Syndrome (SARS)-CoV and SARS-CoV-2, the causative agent of COVID-19. However, the ...evolution and diversification of these coronaviruses remains poorly understood. Here we use a Bayesian statistical framework and a large sequence data set from bat-CoVs (including 630 novel CoV sequences) in China to study their macroevolution, cross-species transmission and dispersal. We find that host-switching occurs more frequently and across more distantly related host taxa in alpha- than beta-CoVs, and is more highly constrained by phylogenetic distance for beta-CoVs. We show that inter-family and -genus switching is most common in Rhinolophidae and the genus Rhinolophus. Our analyses identify the host taxa and geographic regions that define hotspots of CoV evolutionary diversity in China that could help target bat-CoV discovery for proactive zoonotic disease surveillance. Finally, we present a phylogenetic analysis suggesting a likely origin for SARS-CoV-2 in Rhinolophus spp. bats.
Background
Extrathyroid implantation or dissemination of thyroid tissue secondary to a thyroid procedure is rare. Most of these belonged to thyroid carcinoma with metastatic potential and uncommon ...for benign pathologies.
Methods
We report the case of a 31‐year‐old female who was identified to have multiple subcutaneous implantation of thyroid tissue 5 years after transoral endoscopic thyroidectomy vestibular approach. A comprehensive literature search on implantation of thyroid tissue secondary to thyroid procedures was performed.
Results
Accidental tearing of the capsule during previous surgery may lead to the subcutaneous implantation. Through literature review, a total 29 articles with 47 patients were identified. 33.3% were benign lesions, and implantation was mostly secondary to fine needle aspiration biopsy (46.5%).
Conclusions
Subcutaneous or port site implantation after endoscopic thyroid surgery may occur in benign thyroid pathologies and therefore, oncologic principles must be strictly followed during surgery regardless of its histopathological nature.
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