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In current years many chaos-based Substitution boxes (S-boxes) have been proposed. Recently, an image encryption technique based on multiple chaotic S-box was offered. This encryption method was based on the concept of confusion only produced by the implementation of the S-box. The concept of confusion utilized in the understudy technique can be smashed by using just one chosen-plaintext attack and a chosen-ciphertext attack. This article presents a detailed structure of two types of cryptographic attacks on the diffusion-based encryption scheme. The proposed attacks are successfully performed to retrieve the key with very little execution time by using just one chosen image which indicates the vulnerability of multiple chaotic S-boxes-based cryptosystems. The retrieved data is passed through some statistical analysis such as correlation, histogram, and entropy to check the correctness of recovered data.

Many encryption algorithms are designed to decrease the probability of cyberattacks by assuring data security as well as system and participant authentication. However, in the development of computer resources cryptanalytical techniques have been developed and performed competitively in information security with good results. In this paper, we reported security flaws in the recently offered encryption technique based on a chaotic map for Internet of Health Things (IoHT) security. The scheme was based on a new chaotic map, modified Mandelbrot set, and conditional shift algorithm asserting the encryption algorithm is secure. We have performed some cryptographic attacks to retrieve the key from the understudy cryptosystem. The key was retrieved in little computation by using a chosen-plaintext attack and one known plaintext ciphertext pair. The minimum execution time of performed attacks indicates the vulnerability of the diffusion-based encryption algorithm. To enhance the security of the understudy cryptographic algorithm, we have also suggested certain improvements.

The advancement in wireless communication has encouraged the process of data transferring through the Internet. The process of data sharing via the Internet is prone to several attacks. The sensitive information can be protected from hackers with the help of a process called Encryption. Owing to the increase in cyber-attacks, encryption has become a vital component of modern-day communication. In this article, an image encryption algorithm is suggested using dynamic substitution and chaotic systems. The suggested scheme is based upon the chaotic logistic map, chaotic sine maps and the dynamical substitution boxes (S-boxes). In the proposed scheme, the S-box selection is according to the generated sequence by deploying the chaotic sine map. To evaluate the robustness and security of the proposed encryption scheme, different security analysis like correlation analysis, information entropy, energy, histogram investigation, and mean square error are performed. The keyspace and entropy values of the enciphered images generated through the proposed encryption scheme are over 2278 and 7.99 respectively. Moreover, the correlation values are closer to zero after comparison with the other existing schemes. The unified average change intensity (UACI) and the number of pixel change rate (NPCR) for the suggested scheme are greater than 33, 99.50% respectively. The simulation outcomes and the balancing with state-of-the-art algorithms justify the security and efficiency of the suggested scheme.

This paper investigates the dynamical behavior of a single and a network of current modulated edge emitting semiconductor lasers (CMEESLs). Different dynamical behaviors of CMEESL are revealed in two-dimensional parameters space by varying the amplitude and frequency of modulation. Single CMEESL exhibits periodic pulse packages followed by period-doubling cascade to chaotic pulse packages for frequency of modulation current density less than 1 GHz. Microcontroller results which agree with numerical results of single CMEESL are presented. To investigate the dynamics in a network of CMEESLs, a nonlocally coupled lattice array of CMEESLs is analyzed numerically by varying the coupling strength. It is found that the coupling strength plays a significant role in the coherent and incoherent behaviors of the nodes in the network. For a small range of coupling strength, the network exhibits chimera states which are confirmed by their respective state plots. Synchronization error between the nonlocally coupled CMEESLs is also presented to show the existence of chimera states.

The synchronized behavior of neurons depends on the structure and function of the synaptic connections between them. One of the activity-dependent synaptic modifications is the burst-timing-dependent plasticity, which relies on the latencies of the presynaptic and postsynaptic bursts. In this paper, we, therefore, study the collective behavior of a neuronal network with burst-timing-dependent plasticity, in particular, focusing on the emergence of chimera states. We consider separately non-local and global couplings, which have substantial effects on the collective dynamics. We show that the considered burst-timing-dependent plasticity leads to different behavior from static networks. The histogram of the synaptic strengths, in particular, reveals a different evolution of the chimera states in comparison to the development of synchronous and asynchronous states.

While multistability is known as a hot topic in nonlinear dynamics, two exceptional cases of multistable systems have been investigated less: extreme multistable systems and megastable systems are two newer categories of multistable dynamical systems. In this paper, for the first time, a chaotic megastable oscillator is introduced which has a singularity in its equations. The effect of the amplitude and frequency of forcing term on the dynamical behavior of the designed system is investigated. With the help of the bifurcation diagram and the Lyapunov exponents’ diagram, it is shown that the proposed oscillator can show a variety of dynamical behaviors, including limit cycle, torus, and strange attractor.

The outbreak of the novel coronavirus (COVID-19), which was firstly reported in China, has affected many countries worldwide. To understand and predict the transmission dynamics of this disease, mathematical models can be very effective. It has been shown that the fractional order is related to the memory effects, which seems to be more effective for modeling the epidemic diseases. Motivated by this, in this paper, we propose fractional-order susceptible individuals, asymptomatic infected, symptomatic infected, recovered, and deceased (SEIRD) model for the spread of COVID-19. We consider both classical and fractional-order models and estimate the parameters by using the real data of Italy, reported by the World Health Organization. The results show that the fractional-order model has less root-mean-square error than the classical one. Finally, the prediction ability of both of the integer- and fractional-order models is evaluated by using a test data set. The results show that the fractional model provides a closer forecast to the real data.

In this paper a new 5D chaotic system with line equilibrium is designed and described to reveal its extreme multi-stability. Hence, all of the resulting attractors are hidden. The suggested system owns many complex dynamic behaviors in comparison with other chaotic systems. System initial state-associated complex dynamical behaviors are considered and we discover that it possesses an immeasurable number of coexisting attractors, which expresses the occurrence of extreme multi-stability. Besides, we also demonstrate the line equilibrium stability in detail, bifurcation diagrams, Lyapunov exponents, and basins of attraction. Also, in order to analyze the new 5D chaotic system we have considered the permutation entropy technique. Finally, the application of the novel 5D chaotic system with line equilibrium to the problem of chaos synchronization and secure communication through observer design is presented.

Coexistence of attractors with different or same type, multistability, is a complex behavior in nonlinear systems. This feature makes these systems applicable but difficult to control. Besides multistability, some new systems show megastability, existence of infinite number of coexisting attractors. In this paper, two simple megastable systems are presented in details. Moreover, these systems show hyperchaotic behavior which is rare in these types of systems as previously proposed systems mostly show chaos and periodic responses. To show the properties of these systems, nonlinear analytical tools are used in this article.

Chaotic encryption is a growing field for competently shielding visual data. As well as quantum encryption and substitution also play a significant role in applied fields owing to its prospective use in secure communication. This article offers new method for the encryption by utilizing quantum chaotic maps and continuous chaotic dynamical systems. Since chaotic maps are itself suitable for quality encryption coupled with quantum logistic encryption, substitution box stipulates highly secure encryption program. Quantum logistic map is combined with Liu and Rossler chaotic systems with the intention of improvement in efficiency of data randomness. Designed scheme ensures the security of data with the minimum time of encryption. Outcomes acquired from performance evaluation signifies that projected chaotic encryption program reveals high complexity and security.

In recent years, the field of deep learning has played an important role towards automatic detection and classification of diseases in vegetables and fruits. This in turn has helped in improving the quality and production of vegetables and fruits. Citrus fruits are well known for their taste and nutritional values. They are one of the natural and well known sources of vitamin C and planted worldwide. There are several diseases which severely affect the quality and yield of citrus fruits. In this paper, a new deep learning based technique is proposed for citrus disease classification. Two different pre-trained deep learning models have been used in this work. To increase the size of the citrus dataset used in this paper, image augmentation techniques are used. Moreover, to improve the visual quality of images, hybrid contrast stretching has been adopted. In addition, transfer learning is used to retrain the pre-trained models and the feature set is enriched by using feature fusion. The fused feature set is optimized using a meta-heuristic algorithm, the Whale Optimization Algorithm (WOA). The selected features are used for the classification of six different diseases of citrus plants. The proposed technique attains a classification accuracy of 95.7% with superior results when compared with recent techniques.

The fractional order model of a glucose-insulin regulatory system is derived and presented. It has been extensively proved in the literature that fractional order analysis of complex systems can reveal interesting and unexplored features of the system. In our investigations we have revealed that the glucose-insulin regulatory system shows multistability and antimonotonicity in its fractional order form. To show the effectiveness of fractional order analysis, all numerical investigations like stability of the equilibrium points, Lyapunov exponents, and bifurcation plots are derived. Various biological disorders caused by an unregulated glucose-insulin system are studied in detail. This may help better understand the regulatory system.

This paper introduces a simple 1-dimensional map-based model of spiking neurons. During the past decades, dynamical models of neurons have been used to investigate the biology of human nervous systems. The models simulate experimental records of neurons' voltages using difference or differential equations. Difference neuronal models have some advantages besides the differential ones. They are usually simpler, and considering the cost of needed computations, they are more efficient. In this paper, a simple 1-dimensional map-based model of spiking neurons is introduced. Sample entropy is applied to analyze the complexity of the model's dynamics. The model can generate a wide range of time series with different firing rates and different levels of complexities. Besides, using some tools like bifurcation diagrams and cobwebs, the introduced model is analyzed.

This article presents synthetic strategies of different phases and morphologies of nickel selenide in terms of solid state reactions, solvothermal and hydrothermal processes, electrodeposition, precipitation reactions, colloidal synthesis, chemical bath deposition, chemical vapor deposition, solid liquid solution method and composite salt mediated methods. An insight for the applications of nickel selenide in solar cells, water splitting, super capacitors, urea conversion and glucose sensing has also been presented. - 2019 Elsevier Inc. Scopus

The numerical solution of reaction diffusion systems may require more computational efforts if the change in concentrations occurs extremely rapid. This is because more time points are needed to resolve the reaction diffusion process accurately. In this paper, three finite difference implicit schemes are used which are unconditionally stable in order to enhance consistency. Novelty is reported by compact finite difference implicit scheme on a reaction diffusion system with higher accuracy measured by $L_{2}, L_{\infty }$ , and $Relative_{error}$ norms. Efficiency is observed by reducing grid space along small temporal steps. CPU performance, transmission capacity along comparison of three schemes shows excellent agreement with the analytical solution.

Over the last few decades, different mediums of secure communication use chaos which is demonstrated by some nonlinear dynamical systems. Chaos shows unpredictable behavior and this characteristic is quite helpful in different encryption techniques and for multimedia security. In this work, the chaotic behavior of the improved Tent-Sine map is conferred and ultimately a new method to construct substitution-boxes is proposed. This new method explores the features of chaos through TSS map and algebraic Mobius transformation to generate strong S-boxes. The S-boxes are assessed using standard tests suit which includes nonlinearity, strict avalanche criterion, bit independence criterion, linear approximation probability and differential uniformity. Moreover, the proposed S-boxes show excellent statistical properties under majority logic criterions such as correlation, homogeneity, energy, entropy, contrast. The statistical encryption results are demonstrate the better performance of the proposed S-boxes when compared with some of state of the art S-boxes including AES, Gray, APA S8 AES, Skipjack and validate the suitability of anticipated method.

The master stability function (MSF) is a tool to evaluate the local stability of the synchronization in coupled oscillators. Computing the MSF of a network of a specific oscillator results in a curve whose shape is dependent on the nodes' dynamics, network topology, coupling function, and coupling strength. This paper calculates the MSF of networks of two diffusively coupled oscillators by considering different single variable and multi-variable couplings. Then, the linearity of the MSF is investigated by fitting a straight line to the MSF curve, and the root mean square error is obtained. It is observed that the multi-variable coupling with equal coefficients on all variables results in a linear MSF regardless of the dynamics of the nodes.

Megastable chaotic systems are somehow the newest in the family of special chaotic systems. In this paper, a new megastable two-dimensional system is proposed. In this system, coexisting attractors are in some islands, interestingly covered by megalimit cycles. The introduced two-dimensional system has no defined equilibrium point. However, it seems that the origin plays the role of an unstable equilibrium point. Therefore, the attractors are determined as hidden attractors. Adding a forcing term to the system, we can obtain chaotic solutions and coexisting strange attractors. Moreover, the effect of three different values of the forcing term’s amplitude is studied. The dynamical properties of the designed system are investigated using attractor plots, bifurcation diagrams, and Lyapunov Exponents diagram. Phase portraits of the novel megastable oscillator are presented by FPGA design. Xilinx system generator block diagrams of the proposed system and trigonometric functions are also presented.

The fractional calculus in the neuronal models provides the memory properties. In the fractional-order neuronal model, the dynamics of the neuron depends on the derivative order, which can produce various types of memory-dependent dynamics. In this paper, the behaviors of the coupled fractional-order FitzHugh–Nagumo neurons are investigated. The effects of the coupling strength and the derivative order are under consideration. It is revealed that the level of the synchronization is decreased by decreasing the derivative order, and the chimera state emerges for stronger couplings. Furthermore, the patterns of the formed chimeras rely on the order of the derivatives.

The recent decade has witnessed an exponential surge of digital content, especially multimedia and its applications. The security requirements of these innovative platforms necessitate the significance of enhancing advanced encryption schemes. In this paper, a novel encryption scheme is presented for real-time audio applications. The framework of the proposed scheme is grounded on the principles of confusion and diffusion. The confusion incorporates nonlinearity by the application of Mordell elliptic curves (MEC) and a symmetric group of permutations S8. The endurance of the proposed scheme is further enriched through the application of chaotic maps. The proposed scheme is intended to cater requirements of real-time voice communications in defense applications particularly warzones. The adoption of a modular design and fusion of chaotic maps makes the algorithm viable for numerous real-time audio applications. The security can further be enriched by incorporating additional rounds and number of S-boxes in the algorithm. The security and resistance of the algorithm against various attacks are gaged through performance evaluation and security measurements. The audio encryption scheme has the ability to tolerate noise triggered by a channel or induced by an invader. The decryption was successful and the resultant output was audible for noisy data. The overall results depict that the proposed audio encryption scheme contains an excellent cryptographic forte with the minimum computational load. These characteristics allow the algorithm to be a hotspot for modern robust applications.

Finding chaotic oscillators with unique properties is a hot topic. In this paper, a symmetric oscillator with multi-stability is proposed. This oscillator has bounded dynamics for any initial conditions. It is also shown that the oscillator has one unstable equilibrium. This paper studies the dynamical properties of the oscillator, such as chaotic attractors, Lyapunov exponents (LEs), bifurcation diagrams, and the basin of attraction. Its feasibility is shown by circuit implementation. In addition, the stabilization of the system is investigated by impulsive control. This work is partially supported by the Natural Science Basic Research Program of Shaanxi (2021JM-533, 2021JQ-880, 2020JM-646), the Innovation Capability Support Program of Shaanxi (2018GHJD-21), the Science and Technology Program of Xi’an (2019218414GXRC020CG021-GXYD20.3), the Support Plan for Sanqin Scholars Innovation Team in Shaanxi Province of China and the Scientific Research Fund for High-Level Talents of Xijing University (XJ21B01). This work is partially funded by Centre for Nonlinear Systems, Chennai Institute of Technology, India vide funding number CIT/CNS/2021/RD/064.

Studying new chaotic flows with specific characteristics has been an open-ended field of exploring nonlinear dynamics. Investigation of chaotic flows is an area of research that has been taken into consideration for many years; thus, it helps in a better understanding of the chaotic systems. In this paper, an original chaotic 3D system, which has not been investigated yet, is presented in spherical coordinates. A unique feature of the proposed system is that its velocity becomes zero for a specific value of the radius variable. Hence, the system’s attractor is expected to be stuck on one side of a plane in spherical coordinates and inside or outside a sphere in the corresponding Cartesian coordinates. It means that the attractor cannot pass through the sphere or even touch it. The introduced system owns two unstable equilibria and a self-excited strange attractor. The 1D and 2D system’s bifurcation diagrams concerning the alteration of two bifurcation parameters are plotted to investigate the system’s dynamical properties. Moreover, the system’s Lyapunov exponents in the corresponding period of bifurcation parameters are calculated. Then, two 2D basins of attraction for two different third dimension values are explored. Based on the basin of attraction, it can be found that the sphere has attraction itself, partially, and some initial conditions are led to the sphere, not to the strange attractor. Ultimately, the connecting curves of the proposed system are explored to find an informative 1D set in addition to the system’s equilibria.

Designing novel mega-stable chaotic oscillators has been a hot topic of research lately. In the current paper, a two-dimensional mega-stable oscillator is presented. The oscillator has a vast amount of coexisting limit cycles that spread on a surface. The forced version of this system is a novel nonlinear oscillator with an immense number of coexisting limit cycles and chaotic attractors. The dynamical features of this oscillator are examined by the assistance of equilibria study, the plot of the basin of attraction, bifurcation scheme, Lyapunov Exponents (LEs) perspective, and Kaplan-Yorke dimension. This work is funded by the Center for Nonlinear Systems, Chennai Institute of Technology, India, vide funding number CIT/CNS/2021/RP-015.

The recent decade has seen a tremendous escalation of multimedia and its applications. These modern applications demand diverse security requirements and innovative security platforms. In this manuscript, we proposed an algorithm for image encryption applications. The core structure of this algorithm relies on confusion and diffusion operations. The confusion is mainly done through the application of the elliptic curve and S8 symmetric group. The proposed work incorporates three distinct chaotic maps. A detailed investigation is presented to analyze the behavior of chaos for secure communication. The chaotic sequences are then accordingly applied to the proposed algorithm. The modular approach followed in the design framework and integration of chaotic maps into the system makes the algorithm viable for a variety of image encryption applications. The resiliency of the algorithm can further be enhanced by increasing the number of rounds and S-boxes deployed. The statistical findings and simulation results imply that the algorithm is resistant to various attacks. Moreover, the algorithm satisfies all major performance and quality metrics. The encryption scheme can also resist channel noise as well as noise-induced by a malicious user. The decryption is successfully done for noisy data with minor distortions. The overall results determine that the proposed algorithm contains good cryptographic properties and low computational complexity makes it viable to low profile applications.

With the exponential increase in communication sector, the risk of information management also increases. Although there is enormous input from the cybersecurity perspective, still a lot must be done. The substitution box is the most vital component in symmetric encryption algorithms, and various proposals have been presented using chaos. Unfortunately, the full potential of chaos in constructing substitution boxes has not been exploited before. In this paper, we have constructed strong and robust substitution boxes based on Boolean functions incorporating chaos. First, we have developed a new algebraic structure based on the Boolean functions. Second, we have incorporated logistic chaotic map with the proposed algebraic structure to construct strong and robust true-chaotic S-Boxes. Third, the constructed S-Boxes are tested against statistical and security analysis including linear and differential cryptanalysis to demonstrate their strength and robustness. The simulation results and analysis demonstrated that the constructed substitution boxes can resist well-known attacks. Finally, we have done the comparative analysis for statistical, security and cryptanalysis with other well-known works to demonstrate the superiority of our work.

Confidentiality of secret information is one of the mandatory issue of digitally modernized era of science and technology. Due to availability of several online web applications and social media usages nowadays, information is transmitted with ease. The privacy of these digital information can be addressed by using different encryption mechanisms. We have proposed digital information privacy preserving scheme based on three-dimensional chaotic self-exciting single disk homopolar system. Moreover, we have designed a circuit implementations of three-dimensional chaotic self-exciting single disk homopolar dynamical system. The suggested encryption scheme is tested against different security performance analyses which clearly reflects the affectedness of our encryption scheme.

Graphical abstract, Memristor is a non-linear circuit element in which voltage-current relationship is determined by the previous values of the voltage and current, generally the history of the circuit. The nonlinearity in this component can be considered as a fractional-order form, which yields a fractional memristor (fracmemristor). In this paper, a fractional-order memristor in a chaotic oscillator is applied, while the other electronic elements are of integer order. The fractional-order range is determined in a way that the circuit has chaotic solutions. Also, the statistical and dynamical features of this circuit are analyzed. Tools like Lyapunov exponents and bifurcation diagram show the existence of multistability and antimonotonicity, two less common properties in chaotic circuits.

A rare three-dimensional chaotic system with all eigenvalues equal to zero is proposed, and its dynamical properties are investigated. The chaotic system has one equilibrium point at the origin. Numerical analysis shows that the equilibrium point is unstable. Bifurcation analysis of the system shows various dynamics in a period-doubling route to chaos. We highlight that from the evaluation of the entropy, bifurcation points can be predicted by identifying early warning signals. In this manner, bifurcation points of the system are analyzed using Shannon and Kolmogorov-Sinai entropy. The results are compared with Lyapunov exponents.

Smart building control, managing queues for instant points of service, security systems, and customer support can benefit from the number of occupants information known as occupancy. Due to interrupted real-time continuous monitoring capabilities of state-of-the-art cameras, a vision-based system can be easily deployed for occupancy monitoring. However, processing of images or videos over insecure channels can raise several privacy concerns due to constant recording of an image or video footage. In this context, occupancy monitoring along with privacy protection is a challenging task. This paper presents a novel chaos-based lightweight privacy preserved occupancy monitoring scheme. Persons&rsquo, movements were detected using a Gaussian mixture model and Kalman filtering. A specific region of interest, i.e., persons&rsquo, faces and bodies, was encrypted using multi-chaos mapping. For pixel encryption, Intertwining and Chebyshev maps were employed in confusion and diffusion processes, respectively. The number of people was counted and the occupancy information was sent to the ThingSpeak cloud platform. The proposed chaos-based lightweight occupancy monitoring system is tested against numerous security metrics such as correlation, entropy, Number of Pixel Changing Rate (NPCR), Normalized Cross Correlation (NCC), Structural Content (SC), Mean Absolute Error (MAE), Mean Square Error (MSE), Peak to Signal Noise Ratio (PSNR), and Time Complexity (TC). All security metrics confirm the strength of the proposed scheme.

Chaos-based encryption schemes have attracted many researchers around the world in the digital image security domain. Digital images can be secured using existing chaotic maps, multiple chaotic maps, and several other hybrid dynamic systems that enhance the non-linearity of digital images. The combined property of confusion and diffusion was introduced by Claude Shannon which can be employed for digital image security. In this paper, we proposed a novel system that is computationally less expensive and provided a higher level of security. The system is based on a shuffling process with fractals key along with three-dimensional Lorenz chaotic map. The shuffling process added the confusion property and the pixels of the standard image is shuffled. Three-dimensional Lorenz chaotic map is used for a diffusion process which distorted all pixels of the image. In the statistical security test, means square error (MSE) evaluated error value was greater than the average value of 10000 for all standard images. The value of peak signal to noise (PSNR) was 7.69(dB) for the test image. Moreover, the calculated correlation coefficient values for each direction of the encrypted images was less than zero with a number of pixel change rate (NPCR) higher than 99%. During the security test, the entropy values were more than 7.9 for each grey channel which is almost equal to the ideal value of 8 for an 8-bit system. Numerous security tests and low computational complexity tests validate the security, robustness, and real-time implementation of the presented scheme.

The present framework addresses the buoyancy assisting heat and mass transfer of a slender body of revolution, positioned in a saturated porous medium considering thermal radiation and Buongiorno's model. In this analysis, the results are presented for the flow behavior over a paraboloid, a cone, and a cylinder. The governing flow equations are solved and validated numerically by adopting Runge-Kutta-Fehlberg method. The problem of this kind may encounter in automatic industries related to geophysical and geothermal applications where surface heat and mass transport takes place. Effects of involved controlling Physical quantities of the governing systems on heat and mass transfer rates as well as temperature and concentration profiles are reported with the help of tables and graphs. The obtained result indicates that temperature profiles are lesser in the revolution of flow over cone compared to paraboloid and cylinder type of body revolution. This result helps us to conclude the revolution of flow over cone is useful for cooling treatments.

Thermal images play a vital character at nuclear plants, Power stations, Forensic labs biological research, and petroleum products extraction. Safety of thermal images is very important. Image data has some unique features such as intensity, contrast, homogeneity, entropy and correlation among pixels that is why somehow image encryption is trickier as compare to other encryptions. With conventional image encryption schemes it is normally hard to handle these features. Therefore, cryptographers have paid attention to some attractive properties of the chaotic maps such as randomness and sensitivity to build up novel cryptosystems. That is why, recently proposed image encryption techniques progressively more depends on the application of chaotic maps. This paper proposed an image encryption algorithm based on Chebyshev chaotic map and S8 Symmetric group of permutation based substitution boxes. Primarily, parameters of chaotic Chebyshev map are chosen as a secret key to mystify the primary image. Then, the plaintext image is encrypted by the method generated from the substitution boxes and Chebyshev map. By this process, we can get a cipher text image that is perfectly twisted and dispersed. The outcomes of renowned experiments, key sensitivity tests and statistical analysis confirm that the proposed algorithm offers a safe and efficient approach for real-time image encryption.

When we listen regarding quantum cryptography, the first thinking that comes up to mind is, how can there be any connection between physics and cryptographic ciphers. In fact, it comes into view that is one of the hottest research in the field of cryptology to exploit physics and has been confirmed as the important objective in the protection of digital data. The topic of quantum magnets and matrix Lorenz Systems has begun to draw increasing attention in recent years. In last decade, chaotic systems have been utilized in many encryption algorithms. In this regard, Lorenz chaotic system based on differential equations achieved more recognition because of its fundamental sensitivity to initial conditions and easiness in use. This manuscript has two parts. First, we have constructed substitution boxes (S-Boxes) based on quantum magnets and matrix Lorenz chaotic system and permutation of the symmetric group S256 and then designated an image encryption algorithm based on proposed S-boxes and Lorenz chaotic system. In cryptography, it is essential to construct secure S-Boxes to propose cryptographically strong systems. Recently, some image encryption techniques that are weak against robustness have been proposed based on chaotic S-boxes. In the first part of the manuscript, an S-Box design is proposed. Continuous-time Lorenz system is chosen as the chaotic system. The presented image encryption algorithm is based on two rounds of a novel chaotic substitution-permutation network uses proposed S-boxes for substitution purpose by iterations of the Lorenz chaotic system and special kind of permutation process to get the full cipher image. The proposed algorithms for S-box construction and image encryption give very good and coherent performance results when we analyze them with renowned analyses.

Temperature can affect the action potential of a neuron such that the firing pattern is changed under its variation. To incorporate the effects of the temperature, recently, a thermosensitive neuron was proposed in which a thermistor was added to a simple FitzHugh-Nagumo neuron model. Here, thermosensitive neurons are studied to realize the consequence of the thermistor on the neurons’ collective behavior. For specific coupling strengths, the chimera state is developed. The parameter region of the occurrence of the chimera state is obtained by computing the strength of incoherence and shows that the occurrence of the chimera is highly dependent on the coefficient of temperature change in the thermistor. Since, in reality, the neurons are not identical and also the thermistors are not precisely the same, the network is further considered with non-identical neurons. For this purpose, the coefficient of temperature changes in thermistors is not fixed and selected randomly from a normal distribution. The results show that for distributions with a small standard deviation, the behavior of the network changes slightly. While with increasing the standard deviation, the synchronization is achieved for higher coupling strengths, and the region of chimera is extended. Furthermore, although in the asynchronous network the neurons have different attractors, by the appearance of coherent groups and creation of the chimera, the attractors become identical.

Researchers have recently paid significant attention to special chaotic systems. In this work, we introduce an oscillator with different special features. In addition, the oscillator is symmetrical. The features and oscillator dynamics are discovered through different tools of nonlinear dynamics. An electronic circuit is designed to mimic the oscillator’s dynamics. Moreover, the combined synchronization of two drives and one response oscillator is reported. Numerical examples illustrate the correction of our approach. This work is partially funded by Centre for Nonlinear Systems, Chennai Institute of Technology, India vide funding number CIT/CNS/2021/RD/064.

Properties of metal selenides are dependent on their band gaps which can be tuned with size and morphology. Nanotubes particularly are important for their enhanced surface area and reaction sites. Extensive experimental effort has been made over the years on the synthesis of metal selenides nanotubes using templates and without templates. This review article deals with the synthesis of metal selenide nanotubes via chemical methods, hydrothermal methods, solid state reactions, electrochemical methods and UV-irradiation. Applications of metal selenide nanotubes in solar cells, supercapacitors, batteries and water splitting have been discussed and compared with other selenide materials and morphologies.

There have been many different investigations of nonlinear dynamical systems. In this paper, we introduce a new chaotic system. In the proposed system, the attractor can be modified by adding a nonlinear term to the third state equation, thereby generating six different self-excited chaotic attractors. Some dynamical properties such as Hopf bifurcation, bifurcation diagrams, and multistability of the proposed system are investigated. The new system shows topologically different attractors for all six cases. We investigate two cases in depth. We also use nonlinear feedback control to drive the system to equilibrium, using two cases for illustration. Qatar National-Library The publication of this article was funded by the Qatar National-Library.

Background To describe the case of a new born baby with absent nails on fingers. Case report A term female baby was born to 27 years old G3P3 mother of Asian(Chinese)origin via spontaneous vaginal delivery with normal antenatal scans.During routine newborn examination it was found that the nails are absent on the middle and ring finger of both hands with shortening of distal phalanx of right ring finger.Rest of the newborn examination was within normal limits.Findings of fingers were consistent with Anonychia Congenita.There is a strong family history of similar findings in father,uncle and grandfather affecting the fingers of hands and feet. Discussion Anonychia congenita is a rare congenital condition with unknown prevalence which manifest as absence of some or all nails.Inheritance is autosomal dominant.Mutations in R-spodin 4(RSPO4) gene which is located on short arm of chromosome 20 cause anonychia congenita.It can occur as isolated anomaly or as a part of syndromes that affect multiple parts of body like Coffin -Siris syndrome and nail-patella syndrome.

Spiral waves are spatiotemporal patterns, observed in complex networks of biological oscillators such as heart and brain. In this paper, at first a modified Hindmarsh–Rose model with external electromagnetic radiation and discontinuous exponential flux coupling is introduced. Then a 2-dimensional network of the proposed model is constructed. The spatiotemporal patterns of the network are investigated in two different cases of periodic and quasi-periodic external magnetic excitations, by varying the external force parameters. As a consequence, the effective factors on the formation and elimination of spiral waves are reported.

In this article we have comprehensively reported the synthesis, complete chemical characterization (FTIR, multinuclear NMR, single crystal XRD, CHNS, AAS) and biological applications of seventeen ferrocene incorporated selenoureas. Biological applications include comparative DNA binding studies (with, cyclic voltammetry), antioxidant activities (DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging), anti-inflammatory activities (nitrite inhibition), phase I enzyme inhibition activities (aromatase inhibition), phase II enzyme induction studies (quinone reductase induction) and cytotoxic studies against neuroblastoma (MYCN2 and SK-N-SH), liver cancer (Hepa 1c1c7) breast cancer (MCF-7) and human cervical carcinoma HeLa cells (ATCC® CCL-2). All the compounds showed decent structure dependent biological applications. We are thankful to Higher Education Commission Islamabad, Pakistan and Pakistan Academy of Sciences for financial support. Appendix A Scopus

Quantum processing inspired every field of science and technology. Quantum digital content privacy schemes usually employs photons to communicate a key. In this article, we are utilizing different states which correspond to diverse spinning. There are two fundamental particles namely fermions and bosons which are related to half spinning and full spinning. We have utilized the notions of quantum spinning, Hadamard and Redheffer matrices along with Brownian random motion to design robust encryption mechanism. The present scheme is further tested against numerous standards of information security. The simulation outcomes of our presented image encryption scheme attains high level of security, and declines the encryption and the decryption time of image data. - 2019, Springer Science+Business Media, LLC, part of Springer Nature. The authors extent their gratitude to the Deanship of Scientific Research at King Khalid University for funding this work through research groups program under grant number R. G. P-2/58/40. Scopus

In this paper, a new four-dimensional nonlinear oscillator is introduced. This oscillator is memristive and can exhibit chaotic behavior. A complete dynamical analysis is done on each parameter of this system by the help of bifurcation diagram and Lyapunov exponents’ diagram. In order to estimate parameters of the proposed system, we use a new cost function based on the similarity between return maps. Then, with the help of ions motion optimization method, we minimize the obtained cost function and find the exact value of parameters. Scopus