Exploration of field-like torque and field-angle tunability in coupled spin-torque nano oscillators for synchronization.

We investigate the influence of field-like torque and the direction of the external magnetic field on a one-dimensional array of serially connected spin-torque nano oscillators (STNOs), having free layers with perpendicular anisotropy, to achieve complete synchronization between them by analyzing the associated Landau-Lifshitz-Gilbert-Slonczewski equation. The obtained results for synchronization are discussed for the cases of 2, 10, and 100 oscillators separately. The roles of the field-like torque and the direction of the external field on the synchronization of the STNOs are explored through the Kuramoto order parameter. While the field-like torque alone is sufficient to bring out global synchronization in the system made up of a small number of STNOs, the direction of the external field is also needed to be slightly tuned to synchronize the one-dimensional array of a large number of STNOs. The formation of complete synchronization through the construction of clusters within the system is identified for the 100 oscillators. The large amplitude synchronized oscillations are obtained for small to large numbers of oscillators. Moreover, the tunability in frequency for a wide range of currents is shown for the synchronized oscillations up to 100 spin-torque oscillators. In addition to achieving synchronization, the field-like torque increases the frequency of the synchronized oscillations. The transverse Lyapunov exponents are deduced to confirm the stable synchronization in coupled STNOs due to the field-like torque and to validate the results obtained in the numerical simulations. The output power of the array is estimated to be enhanced substantially due to complete synchronization by the combined effect of field-like torque and tunability of the field-angle.

Harnessing vibrational resonance to identify and enhance input signals.

We report the occurrence of vibrational resonance and the underlying mechanism in a simple piecewise linear electronic circuit, namely, the Murali-Lakshmanan-Chua circuit, driven by an additional biharmonic signal with widely different frequencies. When the amplitude of the high-frequency force is tuned, the resultant vibrational resonance is used to detect the low-frequency signal and also to enhance it into a high-frequency signal. Further, we also show that even when the low-frequency signal is changed from sine wave to square and sawtooth waves, vibrational resonance can be used to detect and enhance them into high-frequency signals. These behaviors, confirmed by experimental results, are illustrated with appropriate analytical and numerical solutions of the corresponding circuit equations describing the system. Finally, we also verify the signal detection in the above circuit even with the addition of noise.

Realization of all logic gates and memory latch in the SC-CNN cell of the simple nonlinear MLC circuit.

We investigate the State-Controlled Cellular Neural Network framework of Murali-Lakshmanan-Chua circuit system subjected to two logical signals. By exploiting the attractors generated by this circuit in different regions of phase space, we show that the nonlinear circuit is capable of producing all the logic gates, namely, or, and, nor, nand, Ex-or, and Ex-nor gates, available in digital systems. Further, the circuit system emulates three-input gates and Set-Reset flip-flop logic as well. Moreover, all these logical elements and flip-flop are found to be tolerant to noise. These phenomena are also experimentally demonstrated. Thus, our investigation to realize all logic gates and memory latch in a nonlinear circuit system paves the way to replace or complement the existing technology with a limited number of hardware.

Spiral wave chimera-like transient dynamics in three-dimensional grid of diffusive ecological systems.

In the present article, we demonstrate the emergence and existence of the spiral wave chimera-like transient pattern in coupled ecological systems, composed of prey-predator patches, where the patches are connected in a three-dimensional medium through local diffusion. We explore the transition scenarios among several collective dynamical behaviors together with transient spiral wave chimera-like states and investigate the long time behavior of these states. The transition from the transient spiral chimera-like pattern to the long time synchronized or desynchronized pattern appears through the deformation of the incoherent region of the spiral core. We discuss the transient dynamics under the influence of the species diffusion at different time instants. By calculating the instantaneous strength of incoherence of the populations, we estimate the duration of the transient dynamics characterized by the persistence of the chimera-like spatial coexistence of coherent and incoherent patterns over the spatial domain. We generalize our observations on the transient dynamics in a three-dimensional grid of diffusive ecological systems by considering two different prey-predator systems.

Tunable nonlinear spectra of anti-directional couplers.

We produce transmission and reflection spectra of the anti-directional coupler (ADC) composed of linearly coupled positive- and negative-refractive-index arms, with intrinsic Kerr nonlinearity. Both reflection and transmission feature two highly amplified peaks at two distinct wavelengths in a certain range of values of the gain, making it possible to design a wavelength-selective mode-amplification system. We also predict that a blend of gain and loss in suitable proportions can robustly enhance reflection spectra that are detrimentally affected by the attenuation, in addition to causing red and blue shifts owing to the Kerr effect. In particular, ADC with equal gain and loss coefficients is considered in necessary detail.

Endocrine disrupting chemicals may deregulate DNA repair through estrogen receptor mediated seizing of CBP/p300 acetylase.

PURPOSE: Environmental pollutants are known to induce DNA breaks, leading to genomic instability. Here, we propose a novel mechanism for the genotoxic effects exerted by environmentally exposed endocrine-disrupting chemicals (EDCs). METHODS: Bibliographic research and presentation of the analysis. DISCUSSION: In mammals, nucleotide excision repair, base excision repair, homologous recombination and non-homologous end-joining pathways are some of the major DNA repair pathways. p300 along with CREB-binding protein (CBP) contributes to chromatin remodeling, DNA damage response and repair of both single- and double-stranded DNA breaks. In addition to its role in DNA repair, CBP/p300 also acts as a coactivator to interact with the estrogen receptor and androgen receptor during its estrogen- and androgen-dependent transactivation, respectively. Since activated estrogen receptors (ERs) seize p300 from the repressed genes and redistribute it to the enhancer genes to activate transcription, the cellular functioning may be based on a balance between these pathways and any disturbance in one may alter the other, leading to undesirable physiological effects. CONCLUSION: In conclusion, CBP/p300 is important for DNA repair and nuclear hormone receptor transactivation. Activated hormone receptors can sequester p300 to regulate the hormonal effects. Hence, we believe that activation of ERs by EDCs results in sequestration of CBP/p300 for ER transactivation and transcription initiation of its target genes, leading to a competition for CBP/P300, resulting in the deregulation of all other pathways involving p300/CBP.

Route to logical strange nonchaotic attractors with single periodic force and noise.

Strange nonchaotic attractors (SNAs) have been identified and studied in the literature exclusively in quasiperiodically driven nonlinear dynamical systems. It is an interesting question to ask whether they can be identified with other types of forcings as well, which still remains an open problem. Here, we show that robust SNAs can be created by a small amount of noise in periodically driven nonlinear dynamical systems by a single force. The robustness of these attractors is tested by perturbing the system with logical signals, leading to the emulation of different logical elements in the SNA regions.

Nonlinear anti-directional couplers with gain and loss.

Following the concept of PT-symmetric couplers, we propose a linearly coupled system of nonlinear waveguides, made of positive- and negative-index materials, which carry, respectively, gain and loss. We report novel bi- and multistability states pertaining to transmitted and reflective intensities, which are controlled by the ratio of the gain and loss coefficients, and phase mismatch between the waveguides. These states offer transmission regimes with extremely low threshold intensities for transitions between coexisting states, and very large amplification ratios between the input and output intensities leading to an efficient way of controlling light with light.

Tailoring PT-symmetric soliton switch.

We theoretically demonstrate soliton steering in parity-time (PT)-symmetric coupled nonlinear dimers. We show that if the length of the PT-symmetric system is set to 2π, contrary to the conventional one that operates satisfactorily well only at the half-beat coupling length, the PT dimer remarkably yields an ideal soliton switch exhibiting almost 99.99% energy efficiency with an ultralow critical power.

Nondegenerate Solitons in Manakov System.

It is known that the Manakov equation which describes wave propagation in two mode optical fibers, photorefractive materials, etc., can admit solitons which allow energy redistribution between the modes on collision that also leads to logical computing. In this Letter, we point out that the Manakov system can admit a more general type of nondegenerate fundamental solitons corresponding to different wave numbers, which undergo collisions without any energy redistribution. The previously known class of solitons which allows energy redistribution among the modes turns out to be a special case corresponding to solitary waves with identical wave numbers in both the modes and traveling with the same velocity. We trace out the reason behind such a possibility and analyze the physical consequences.

A Multimodal Authentication for Biometric Recognition System using Intelligent Hybrid Fusion Techniques.

Biometric Recognition and Authentication is used in many applications for the secured identification of the persons. Several Researches has been carried out to strengthen the security algorithms through which the identification can be done in secured manner. With this objective, a new algorithm called Hybrid Adaptive Fusion(HAF) has been proposed which works on the principle of hybrid fusion of two feature inputs such as Hand geometry and iris of the users. As mentioned, the proposed algorithm uses the novel and hybrid fusion of feature extraction along with the accurate machine learning classifier. Effective Linear Binary Patterns (ELBP) and Scale Invariant Fourier Transform (SIFT) are stored in the databases for the further verification. The features stored are fed into the Extreme Learning machines for the detection of the verified users. This algorithm has been tested with the CASIA Image Datasets and with the different classifiers such as Neural Networks, Baiyes Networks. The proposed algorithm with ELM has better accuracy of 98.5% when compared with the other machine learning algorithms.

No calcitonin change in a person taking dulaglutide diagnosed with pre-existing medullary thyroid cancer.

BACKGROUND: Glucagon-like peptide-1 receptor agonists, such as dulaglutide, exenatide and liraglutide, are approved to treat Type 2 diabetes mellitus. Although these drugs provide substantial glycaemic control, studies in rodents have prompted concerns about the development of medullary thyroid carcinoma. These data are reflected in the US package insert, with boxed warnings and product labelling noting the occurrence of these tumours after clinically relevant exposures in rodents, and contraindicating glucagon-like peptide-1 receptor agonist use in people with a personal or family history of medullary thyroid carcinoma, or in people with multiple endocrine neoplasia type 2. However, there are substantial differences between rodent and human responses to glucagon-like peptide-1 receptor agonists. This report presents the case of a woman with pre-existing medullary thyroid carcinoma who exhibited no significant changes in serum calcitonin levels despite treatment with dulaglutide 2.0 mg for 6 months in the Assessment of Weekly AdministRation of LY2189265 [dulaglutide] in Diabetes-5 clinical study (NCT00734474). CASE REPORT: Elevated serum calcitonin was noted in a 56-year-old woman with Type 2 diabetes mellitus at the 6-month discontinuation visit in a study of long-term dulaglutide therapy. Retroactive assessment of serum collected before study treatment yielded an elevated calcitonin level. At 3 months post-study, calcitonin level remained elevated; ultrasonography revealed multiple bilateral thyroid nodules. Eventually, medullary thyroid carcinoma was diagnosed; the woman was heterozygous positive for a germline RET proto-oncogene mutation. CONCLUSION: The tumour was not considered stimulated by dulaglutide therapy because calcitonin remained stable throughout.

Stable amplitude chimera states in a network of locally coupled Stuart-Landau oscillators.

We investigate the occurrence of collective dynamical states such as transient amplitude chimera, stable amplitude chimera, and imperfect breathing chimera states in a locally coupled network of Stuart-Landau oscillators. In an imperfect breathing chimera state, the synchronized group of oscillators exhibits oscillations with large amplitudes, while the desynchronized group of oscillators oscillates with small amplitudes, and this behavior of coexistence of synchronized and desynchronized oscillations fluctuates with time. Then, we analyze the stability of the amplitude chimera states under various circumstances, including variations in system parameters and coupling strength, and perturbations in the initial states of the oscillators. For an increase in the value of the system parameter, namely, the nonisochronicity parameter, the transient chimera state becomes a stable chimera state for a sufficiently large value of coupling strength. In addition, we also analyze the stability of these states by perturbing the initial states of the oscillators. We find that while a small perturbation allows one to perturb a large number of oscillators resulting in a stable amplitude chimera state, a large perturbation allows one to perturb a small number of oscillators to get a stable amplitude chimera state. We also find the stability of the transient and stable amplitude chimera states and traveling wave states for an appropriate number of oscillators using Floquet theory. In addition, we also find the stability of the incoherent oscillation death states.

Implementation of dynamic dual input multiple output logic gate via resonance in globally coupled Duffing oscillators.

We have used a system of globally coupled double-well Duffing oscillators under an enhanced resonance condition to design and implement Dual Input Multiple Output (DIMO) logic gates. In order to enhance the resonance, the first oscillator in the globally coupled system alone is excited by two forces out of which one acts as a driving force and the other will be either sub-harmonic or super-harmonic in nature. We report that for an appropriate coupling strength, the second force coherently drives and enhances not only the amplitude of the weak first force to all the coupled systems but also drives and propagates the digital signals if any given to the first system. We then numerically confirm the propagation of any digital signal or square wave without any attenuation under an enhanced resonance condition for an amplitude greater than a threshold value. Further, we extend this idea for computing various logical operations and succeed in designing theoretically DIMO logic gates such as AND/NAND, OR/NOR gates with globally coupled systems.

Design and implementation of dynamic logic gates and R-S flip-flop using quasiperiodically driven Murali-Lakshmanan-Chua circuit.

We report the propagation of a square wave signal in a quasi-periodically driven Murali-Lakshmanan-Chua (QPDMLC) circuit system. It is observed that signal propagation is possible only above a certain threshold strength of the square wave or digital signal and all the values above the threshold amplitude are termed as "region of signal propagation." Then, we extend this region of signal propagation to perform various logical operations like AND/NAND/OR/NOR and hence it is also designated as the "region of logical operation." Based on this region, we propose implementing the dynamic logic gates, namely, AND/NAND/OR/NOR, which can be decided by the asymmetrical input square waves without altering the system parameters. Further, we show that a single QPDMLC system will produce simultaneously two outputs which are complementary to each other. As a result, a single QPDMLC system yields either AND as well as NAND or OR as well as NOR gates simultaneously. Then, we combine the corresponding two QPDMLC systems in a cross-coupled way and report that its dynamics mimics that of fundamental R-S flip-flop circuit. All these phenomena have been explained with analytical solutions of the circuit equations characterizing the system and finally, the results are compared with the corresponding numerical and experimental analysis.

Treatment satisfaction in people with type 2 diabetes mellitus treated with once-weekly dulaglutide: data from the AWARD-1 and AWARD-3 clinical trials.

AIMS: To compare treatment satisfaction among people with type 2 diabetes receiving dulaglutide 1.5 mg and dulaglutide 0.75 mg (a once-weekly, long-acting, glucagon-like peptide-1 receptor agonist) with those receiving either exenatide or placebo (AWARD-1 study) or metformin (AWARD-3 study) over 52 weeks. METHODS: The Diabetes Treatment Satisfaction Questionnaire status version (DTSQs) and change version (DTSQc) were used to evaluate total treatment satisfaction and perceived frequency of hyperglycaemia and hypoglycaemia. RESULTS: In the AWARD-1 study, significant improvements from baseline were observed in total DTSQs score for both dulaglutide doses (26 and 52 weeks) and exenatide (26 weeks). The improvement was significantly greater with both dulaglutide doses compared with placebo (26 weeks) and exenatide (26 and 52 weeks). The perceived frequency of hyperglycaemia was lower for all groups at 26 and 52 weeks compared with baseline. The improvement was greater with both dulaglutide doses and exenatide compared with placebo at 26 weeks, and was also greater with both dulaglutide doses compared with exenatide at 26 and 52 weeks. The exenatide group had an increase in perceived frequency of hypoglycaemia at 26 and 52 weeks. In the AWARD-3 study, significant improvements from baseline were observed for total DTSQs scores in all groups at 26 and 52 weeks. Perceived frequency of hyperglycaemia was lower for all groups at 26 and 52 weeks compared with baseline, and this improvement was greater with both dulaglutide doses compared with metformin at 52 weeks. CONCLUSIONS: Dulaglutide was associated with improvements in treatment satisfaction and a decrease in perceived frequency of hyperglycaemia.

Applicability of 0-1 test for strange nonchaotic attractors.

We show that the recently introduced 0-1 test can successfully distinguish between strange nonchaotic attractors (SNAs) and periodic/quasiperiodic/chaotic attractors, by suitably choosing the arbitrary parameter associated with the translation variables in terms of the golden mean number which avoids resonance with the quasiperiodic force. We further characterize the transition from quasiperiodic to chaotic motion via SNAs in terms of the 0-1 test. We demonstrate that the test helps to detect different dynamical transitions to SNAs from quasiperiodic attractor or the transitions from SNAs to chaos. We illustrate the performance of the 0-1 test in detecting transitions to SNAs in quasiperiodically forced logistic map, cubic map, and Duffing oscillator.

Simulation of universal optical logic gates under energy sharing collisions of Manakov solitons and fulfillment of practical optical logic criteria.

The universal optical logic gates, namely, nand and nor gates, have been theoretically simulated by employing the energy sharing collision of bright optical solitons in the Manakov system, governing pulse propagation in a highly birefringent fiber. Further, we also realize the two-input optical logic gates, such as and, or, xor, xnor, for completeness of our scheme. Interestingly, our idea behind the simulation naturally satisfies all the criteria for practical optical logic, which in turn displays the strength and versatility of our theoretical simulation of universal optical logic gates. Hence, our approach paves the way for the experimentalists to create a new avenue in this direction if the energy sharing collisions of Manakov solitons are experimentally realized in the future.

The effect of teriparatide compared with risedronate on reduction of back pain in postmenopausal women with osteoporotic vertebral fractures.

UNLABELLED: The effect of teriparatide and risedronate on back pain was tested, and there was no difference in the proportion of patients experiencing a reduction in back pain between groups after 6 or 18 months. Patients receiving teriparatide had greater increases in bone mineral density and had fewer vertebral fractures. INTRODUCTION: This study aimed to understand the effect of teriparatide in reducing back pain in patients with prevalent back pain and vertebral fracture compared to risedronate. METHODS: In an 18-month randomized, double-blind, double-dummy trial, we investigated the effects of teriparatide (20 µg/day) vs. risedronate (35 mg/week) in postmenopausal women with back pain likely due to vertebral fracture. The primary objective was to compare the proportion of subjects reporting ≥30% reduction in worst back pain severity from baseline to 6 months as assessed by a numeric rating scale in each treatment group. Pre-specified secondary and exploratory outcomes included assessments of average and worst back pain at additional time points, disability and quality of life, bone mineral density, incidence of fractures, and safety. RESULTS: At 6 months, 59% of teriparatide and 57% of risedronate patients reported ≥30% reduction in worst back pain and there were no differences between groups in the proportion of patients experiencing reduction in worst or average back pain at any time point, disability, or quality of life. There was a greater increase from baseline in bone mineral density at the lumbar spine (p = 0.001) and femoral neck (p = 0.02) with teriparatide compared to risedronate and a lower incidence of vertebral fractures at 18 months (4% teriparatide and 9% risedronate; p = 0.01). Vertebral fractures were less severe (p = 0.04) in the teriparatide group. There was no difference in the overall incidence of adverse events. CONCLUSIONS: Although there were no differences in back pain-related endpoints, patients receiving teriparatide had greater skeletal benefit than those receiving risedronate.

Anticipating, complete and lag synchronizations in RC phase-shift network based coupled Chua's circuits without delay.

We construct a new RC phase shift network based Chua's circuit, which exhibits a period-doubling bifurcation route to chaos. Using coupled versions of such a phase-shift network based Chua's oscillators, we describe a new method for achieving complete synchronization (CS), approximate lag synchronization (LS), and approximate anticipating synchronization (AS) without delay or parameter mismatch. Employing the Pecora and Carroll approach, chaos synchronization is achieved in coupled chaotic oscillators, where the drive system variables control the response system. As a result, AS or LS or CS is demonstrated without using a variable delay line both experimentally and numerically.