Nitric oxide (NO) is an important molecule in headache pathophysiology. NO regulates vascular tone and acts as a potent vasodilator, and thus participates in regulating blood flow. NO is also considered to play a role in processing sensory information and pain sensitization. In this article, we review the role of NO in one of the primary headache disorders, cluster headache (CH). The pathophysiology of CH is still not completely understood. A multifactorial genesis where NO is likely to be involved is probable. The level of NO production has been shown to correlate with disease activity in several inflammatory disorders, such as cystitis, multiple sclerosis, and cerebral lupus erythematosus. In this article, the issue of whether similar circumstances apply for CH and also the role of NO in the pathophysiology of CH in a wider perspective are discussed.

Role of nitric oxide in cluster headache.

This paper aims to investigate stochastic dynamics of nonlinear vibro-impact system with viscoelastic term subjected to wide-band noise. Firstly, the viscoelastic term is approximated as equivalent damping and stiffness forces. Then, the non-smooth transformation is adopted to convert the vibro-impact system into a system without barriers. By using of the stochastic averaging method based on generalized harmonic function, the probability densities of the stationary response are obtained and dynamical influence of viscoelastic parameters and restitution coefficient of the system are discussed as well. Comparison between the analytical simulation and numerical simulation results shows an excellent agreement.

Stochastic response of Duffing-Van der Pol vibro-impact system with viscoelastic term under wide-band excitation

Several medications have been proposed as the first line drugs in the treatment of migraine attack. However, the low efficacy, potential complications of medications and the intolerance of some patients for oral route due to nausea and vomiting establish a difficult situation in some migraine patients. This report describes a dramatic pain relief with 60 mg of intravenous propofol in a patient with migraine attack refractory to treatment with metoclopramide, promethazine, dexamethasone and meperidine. Pain relief in this patient besides earlier case reports suggests that subanesthetic doses of propofol may be an alternative to other treatment modalities for acute migraine.

/pdf/propofol-alleviates-intractable-migraine-headache-a-case-3cpijpc7hk.pdf

Propofol alleviates intractable migraine headache: a case report.

The stochastic P-bifurcation behavior of a bistable Van der Pol system with fractional time-delay feedback under Gaussian white noise excitation is studied. Firstly, based on the minimal mean square error principle, the fractional derivative term is found to be equivalent to the linear combination of damping force and restoring force, and the original system is further simplified to an equivalent integer order system. Secondly, the stationary Probability Density Function (PDF) of system amplitude is obtained by stochastic averaging, and the critical parametric conditions for stochastic P-bifurcation of system amplitude are determined according to the singularity theory. Finally, the types of stationary PDF curves of system amplitude are qualitatively analyzed by choosing the corresponding parameters in each area divided by the transition set curves. The consistency between the analytical solutions and Monte Carlo simulation results verifies the theoretical analysis in this paper.

/pdf/stochastic-p-bifurcation-in-a-bistable-van-der-pol-sbyflbyl6z.pdf

Stochastic P-bifurcation in a bistable Van der Pol oscillator with fractional time-delay feedback under Gaussian white noise excitation

This paper investigates the stochastic P-bifurcation behavior of bistability in a generalized Van der Pol system with fractional time-delay feedback under additive and multiplicative Gaussian white...

https://journals.sagepub.com/doi/pdf/10.1177/1461348419878534

Stochastic P-bifurcation in a generalized Van der Pol oscillator with fractional delayed feedback excited by combined Gaussian white noise excitations:

The principal resonance of Duffing oscillator to combined deterministic and random external excitation was investigated. The random excitation was taken to be white noise or harmonic with separable random amplitude and phase. The method of multiple scales was used to determine the equations of modulation of amplitude and phase. The one peak probability density function of each of the two stable stationary solutions was calculated by the linearization method. These two one-peak-density functions were combined using the probability of realization of the two stable stationary solutions to obtain the double peak probability density function. The theoretical analysis are verified by numerical results.

On double peak probability density functions of duffing oscillator to combined deterministic and random excitations

The response of visco-elastic system to combined deterministic harmonic and random excitation was investigated. The method of harmonic balance and the method of stochastic averaging were used to determine the response of the system. The theoretical analysis was verified by numerical results. Theoretical analyses and numerical simulations show that when the intensity of the random excitation increase, the nontrivial steady state solution may change from a limit cycle to a diffused limit cycle. Under some conditions the system may have two steady slate solutions and jumps may exist.

Visco-elastic systems under both deterministic harmonic and random excitation

This paper gives the direct formulas of stiffness matrixes of two kinds of Kirchhoff nonlinear elements under total-Lagrange coordinate. For the first one, it includes not only the quadric terms of increments of strain and displacement but also the influence of rotations. For the second one, it is simplified and its nonlinear is considered by taking into account the influence of axial force on the equilibrium equation in the linear beam theory.

方同

Papers

On double peak probability density functions of duffing oscillator to combined deterministic and random excitations

Visco-elastic systems under both deterministic harmonic and random excitation

The nonlinear numerical analysis method for frames