background: application noninvasive ventilation in the patients with exacerbation of chronic obstructive pulmonary disease (copd) reduced mortality. this case-control study was designed to compare efficiency and outcome of non-invasive (niv) versus invasive positive pressure ventilation (ippv) in respiratory failure due to copd methods: the patients were assigned to niv or ippv intermittantly.t...

Recently, bulk nano-structured materials produced by severe plastic deformation (SPD) have attracted scientists attention.  Materials produced by SPD are of great importance because of (1) non-porous structure, (2) great mechanical properties such as high strength and toughness and (3) proper dimension for mechanical and physical testing.  Several methods have been introduced for imposing the s...

In this paper, the general solution of steady-state two-dimensional non-axisymmetric mechanical and thermal stresses and mechanical displacements of a hollow thick cylinder made of fluid-saturated functionally graded porous material (FGPM) is presented. The general form of thermal and mechanical boundary conditions is considered on the inside and outside surfaces. A direct method is used to sol...

background: today, electronic mass media such as television (tv), influence behavioral patterns of their audiences. this study aimed to evaluate what messages on food advertisements related to oral health were transmitted (appeals) and how they were transferred (performance methods & artistic techniques) in islamic republic of iran broadcasting (irib). methods: in this cross sectional study, br...