A Hybrid Brain-Computer Interface for Closed-Loop Position Control of a Robot Arm

Brain-Computer interfacing(BCI)has currently added a new dimension in assistive robotics.Existing braincomputer interfaces designed for position control applications suffer from two fundamental limitations.First,most of the existing schemes employ open-loop control,and thus are unable to track positional errors,resulting in failures in taking necessary online corrective actions.There are examples of a few works dealing with closed-loop electroencephalography(EEG)-based position control.These existing closed-loop brain-induced position control schemes employ a fixed order link selection rule,which often creates a bottleneck preventing time-efficient control.Second,the existing brain-induced position controllers are designed to generate a position response like a traditional firstorder system,resulting in a large steady-state error.This paper overcomes the above two limitations by keeping provisions for steady-state visual evoked potential(SSVEP)induced linkselection in an arbitrary order as required for efficient control and generating a second-order response of the position-control system with gradually diminishing overshoots/undershoots to reduce steady-state errors.Other than the above,the third innovation is to utilize motor imagery and P300 signals to design the hybrid brain-computer interfacing system for the said application with gradually diminishing error-margin using speed reversal at the zero-crossings of positional errors.Experiments undertaken reveal that the steady-state error is reduced to 0.2%.The paper also provides a thorough analysis of the stability of the closed-loop system performance using the Root Locus technique.

Therapeutic potential and pharmacological mechanism of visnagin

Visnagin is a furanochromone and one of the most important compound in the Ammi visnaga(L.)Lam(a synonym of Visnaga daucoides Gaertn.)plant,which is used to cure various ailments.Many investigations into the bioactive properties of visnagin have been studied to date.The literature on visnagin demonstrates its biological properties,including anti-inflammatory,anti-diabetic,and beneficial effects in cardiovascular and renal diseases.Moreover,visnagin improves sperm quality parameters,stimulates steroidogenesis,and increases serum gonadotropins and testosterone levels,while decreasing proinflammatory cytokines,oxidative damage,genomic instability,and it modulates apoptosis.Thus,visnagin has emerged as an exciting lead for further research,owing to its potential in various unmet clinical needs.The current review summarized its basic structure,pharmacokinetics,and pharmacological effects,focusing on its mechanisms of action.The review will help to understand the potential of visnagin as an alternative treatment strategy for several diseases and provide insight into research topics that need further exploration for visnagin’s safe clinical use.