Search

Intragastric balloon (IGB) therapy has shown efficacy in weight loss but its role in NAFLD remains unknown. We conducted a systematic review and meta-analysis to evaluate the efficacy of IGB in NAFLD. Meta-analysis was performed to estimate the pooled proportion of patients with improvement in steatosis as determined by imaging and histology following IGB placement. Nine studies were included in our analysis. Four hundred forty-two IGBs were placed. Improvement in steatosis was seen in 79.2% of patients and NAS in 83.5% of patients, and HOMA-IR score improved in 64.5% of patients. A reduction in liver volume by CT scan was noticed in 93.9% of patients undergoing IGB placement. IGB is an effective and safe short-term therapeutic modality for patients with NAFLD.

The propagation properties of electrostatic cnoidal waves (periodic waves) and solitons are studied in a magnetized electron-positron-ion (EPI) plasma bearing ion pressure anisotropy and superthermality. In a two-dimensional geometry, we considered the ions to be warm having pressure anisotropy due to magnetic field. The anisotropic ions are modeled via double adiabatic Chew-Golberger-Low (CGL) theory and the lighter species (electron and positron) are following kappa distributions. A Korteweg-de Vries (KdV)-type equation is derived by employing reductive perturbation technique, and obtained the nonlinear periodic waves solutions with appropriate boundary conditions. The anisotropy in the ion thermal pressure relative to the external magnetic field (different values in parallel and perpendicular directions) have significant effects on the characteristics of cnoidal waves. It is observed that by increasing the ion parallel and perpendicular pressure (keeping the relative anisotropy) tends to reduce the wavelength of the cnoidal wave structure, while the amplitude tends to increase. The influence of superthermality of electron and positron, the positron content and strength of the external magnetic field on the cnoidal waves are studied in detail. Furthermore, phase portrait analysis is carried out and traced out the equilibrium points around which nonlinear periodic waves can be formed. The saddle points which correspond to the homoclinic orbits are also shown. The investigation can be useful in exploring the nonlinear wave dynamics in both laboratory and space plasma where ion pressure anisotropy and superthermality exist.

A theory of double-pulse photodetachment spectra in the presence of time dependent field has been developed. We derived a general formula for the total population generated by the double-pulse laser applying the time dependent closed orbit theory. We analyzed the double-pulse spectra for H− in the presence of constant electric field superposed with a sinusoidal time dependent field. The effects of the amplitude of time dependent field and laser parameters have been investigated. It has been shown that the population has peak or valley when the time delay between the two pulses of the double-pulse laser is equal to the time of the closed orbit emanating at the peak of the first pulse of the double-pulse laser. We also shown that the laser phase parameter modulates the population.

The propagation of linear and nonlinear electrostatic waves is investigated in magnetized dusty plasma with stationary negatively or positively charged dust, cold mobile ions and non-extensive electrons. Two normal modes are predicted in the linear regime, whose characteristics are investigated parametrically, focusing on the effect of electrons non-extensivity, dust charge polarity, concentration of dust and magnetic field strength. Using the reductive perturbation technique, a Zakharov-Kuznetsov (ZK) type equation is derived which governs the dynamics of small-amplitude solitary waves in magnetized dusty plasma. The properties of the solitary wave structures are analyzed numerically with the system parameters i.e. electrons non-extensivity, concentration of dust, polarity of dust and magnetic field strength. Following Allen and Rowlands (J. Plasma Phys. 53:63, 1995), we have shown that the pulse soliton solution of the ZK equation is unstable, and have analytically traced the dependence of the instability growth rate on the nonextensive parameter $q$ for electrons, dust charge polarity and magnetic field strength. The results should be useful for understanding the nonlinear propagation of DIA solitary waves in laboratory and space plasmas.