New hyperchaotic system with single nonlinearity, its electronic circuit and encryption design based on current conveyor

Nowadays, hyperchaotic system (HCSs) have been started to be used in engineering applications because they have complex dynamics, randomness, and high sensitivity. For this purpose, HCSs with different features have been introduced in the literature. In this work, a new HCS with a single discontinuous nonlinearity is introduced and analyzed. The proposed system has one saddle focus equilibrium. When the dynamic properties and bifurcation graphics of the system are analyzed, it is determined that the proposed system exhibits the complex phenomenon of multistability. Moreover, analog electronic circuit design of the proposed system is performed with positive second-generation current conveyor. In addition, an encryption circuit is designed to demonstrate that the proposed system can be used in various engineering applications

COVID-19: Sleep, Circadian Rhythms and Immunity – Repurposing Drugs and Chronotherapeutics for SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has affected nearly 28 million people in the United States and has caused more than five hundred thousand deaths as of February 21, 2021. As the novel coronavirus continues to take its toll in the United States and all across the globe, particularly among the elderly (>65 years), clinicians and translational researchers are taking a closer look at the nexus of sleep, circadian rhythms and immunity that may contribute toward a more severe coronavirus disease-19 (COVID-19). SARS-CoV-2-induced multi-organ failure affects both central and peripheral organs, causing increased mortality in the elderly. However, whether differences in sleep, circadian rhythms, and immunity between older and younger individuals contribute to the age-related differences in systemic dysregulation of target organs observed in SARS-CoV-2 infection remain largely unknown. Current literature demonstrates the emerging role of sleep, circadian rhythms, and immunity in the development of chronic pulmonary diseases and respiratory infections in human and mouse models. The exact mechanism underlying acute respiratory distress syndrome (ARDS) and other cardiopulmonary complications in elderly patients in combination with associated comorbidities remain unclear. Nevertheless, understanding the critical role of sleep, circadian clock dysfunction in target organs, and immune status of patients with SARS-CoV-2 may provide novel insights into possible therapies. Chronotherapy is an emerging concept that is gaining attention in sleep medicine. Accumulating evidence suggests that nearly half of all physiological functions follow a strict daily rhythm. However, healthcare professionals rarely take implementing timed-administration of drugs into consideration. In this review, we summarize recent findings directly relating to the contributing roles of sleep, circadian rhythms and immune response in modulating infectious disease processes, and integrate chronotherapy in the discussion of the potential drugs that can be repurposed to improve the treatment and management of COVID-19

Novel ALDH3A2 mutations in structural and functional domains of FALDH causing diverse clinical phenotypes in Sjögren-Larsson Syndrome patients

Mutations in ALDH3A2 cause Sjögren-Larsson Syndrome (SLS), a neuro-ichthyotic condition that is caused by deficiency of fatty aldehyde dehydrogenase (FALDH). We screened for novel mutations causing SLS among Indian ethnicity, characterized the identified mutations in silico and in vitro; and retrospectively evaluated their role in phenotypic heterogeneity. Interestingly, asymmetric distribution of non-classical traits was observed in our cases. Nerve conduction studies suggested intrinsic-minus-claw hands in two siblings, a novel neurological phenotype to SLS. Genetic testing revealed 5 novel homozygous ALDH3A2 mutations in six cases: Case-1-NM_000382.2:c.50C>A, NP_000373.1:p.(Ser17Ter); Case-2-NM_000382.2:c.199G>T, NP_000373.1:p.(Glu67Ter); Case-3-NM_000382.2:c.1208G>A, NP_000373.1:p.(Gly403Asp); Case-4-NM_000382.2:c.1325C>T, NP_000373.1:p.(Pro442Leu); Case-5&6-NM_000382.2:c.1349G>A, NP_000373.1:p.(Trp450Ter). The mutations identified were predicted to be pathogenic and disrupts the functional domains of the FALDH. p.(Pro442Leu) at the C-terminal α-helix, might impair substrate gating process. Mammalian expression studies with exon-9 mutants confirmed the profound reduction in the enzyme activity. Diminished aldehyde oxidizing activity was observed with cases-2&3. Cases-2 & 3 showed epidermal hyperplasia with mild intracellular edema, spongiosis, hypergranulosis, and perivascular-interstitial lymphocytic infiltrate and a leaky eosinophilic epidermis. The presence of keratin-milia like lipid vacuoles implies defective lamellar secretion with p.(Gly403Asp). This study improves our understanding of the clinical and mutational diversity in SLS, which might help to fast-track diagnostic and therapeutic interventions of this debilitating disorder. This article is protected by copyright. All rights reserved

Recent updates on the role of extracellular vesicles in the pathogenesis of allergic asthma

Asthma is a chronic inflammatory disease of the airway diagnosed with different endotypes and phenotypes, characterized by airway obstruction in response to allergens, bacterial/viral infections, or pollutants. Several cell types such as the airway epithelial cells, mesenchymal stem cells and different immune cells including dendritic cells (DCs), T and B cells and mast cells play an essential role during the pathobiology of asthma. Extracellular vesicles (EVs) are membranous nanovesicles produced by every cell type that facilitates intercellular communications. EVs contain heterogeneous cargos that primarily depend on the composition or cell type of origin and they can alter the physiological state of the target cells. EVs encompass a wide variety of proteins including Tetraspanins, MHC classes I and II, co-stimulatory molecules, nucleic acids such as RNA, miRNA, piRNA, circRNA, and lipids like ceramides and sphingolipids. Recent literature indicates that EVs play a pivotal role in the pathophysiology of allergic asthma and may potentially be used as a novel biomarker to determine endotypes and phenotypes in severe asthmatics. Based on the prior reports, we speculate that regulation of EVs biogenesis and release might be under the control of circadian rhythms. Thus, circadian rhythms may influence the composition of the EVs, which alter the microenvironment that results in the induction of an immune-inflammatory response to various environmental insults or allergens such as air pollutants, ozone, diesel exhaust particles, pollens, outdoor molds, environmental tobacco smoke, etc. In this mini-review, we summarize the recent updates on the novel role of EVs in the pathogenesis of asthma, and highlight the link between circadian rhythms and EVs that may be important to identify molecular mechanisms to target during the pathogenesis of chronic inflammatory lung disease such as asthma

Complex novel 4D memristor hyperchaotic system and its synchronization using adaptive sliding mode control

First, this paper announces a flux controlled novel 4-D chaotic system displaying chaotic attractor modified from a 4D hyperchaotic system. The phase portraits of the novel chaotic system are displayed and the qualitative properties are discussed. Next we derive the complex model of the proposed 4D system. We investigate the dynamic properties of the complex systems. Adaptive sliding mode control is used to achieve non-identical synchronization of the complex systems. Numerical simulations are conducted to validate the results. Keywords: Chaos, 4D systems, Hyperchaotic systems, Sliding mode control, Chaos synchronization, Lyapunov stabilit

Effect of Noise variance in spiral wave suppression for a multi-layered neuron model with flux coupling modelled using a memristor

Dynamics of multi-layered neuronal network are challenging and spiral wave suppression is vital particularly in biological systems such as cortical tissue in brain, heart muscles etc., In this study, one-, two- and three-layer neuronal network of an exponential flux memristor-based Morris-Lecar neuron model subjected to low-frequency electromagnetic field (MLELF) is considered and the influence of noise variance in spiral wave suppression is investigated. A Box- Muller type Gaussian noise is used as stimulation and the influence of noise variance on neuronal network is studied. The results exposed the multilayer neuronal network influenced much by a very low noise variance on spiral wave suppression while compared with the single-layer network. As increase in noise variance, the dynamics of the spiral wave changes significantly and ended with turbulence. The study highlighted the spiral waves can be potentially suppressed even the network is under higher frequency external electric field using noise variance

Dynamical Analysis and FPGA Implementation of a Novel Hyperchaotic System and Its Synchronization Using Adaptive Sliding Mode Control and Genetically Optimized PID Control

We announce a new 4D hyperchaotic system with four parameters. The dynamic properties of the proposed hyperchaotic system are studied in detail; the Lyapunov exponents, Kaplan-Yorke dimension, bifurcation, and bicoherence contours of the novel hyperchaotic system are derived. Furthermore, control algorithms are designed for the complete synchronization of the identical hyperchaotic systems with unknown parameters using sliding mode controllers and genetically optimized PID controllers. The stabilities of the controllers and parameter update laws are proved using Lyapunov stability theory. Use of the optimized PID controllers ensures less time of convergence and fast synchronization speed. Finally the proposed novel hyperchaotic system is realized in FPGA