Shahid Beheshti University of Medical Sciences and Health Services

About: Shahid Beheshti University of Medical Sciences and Health Services is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Population & Medicine. The organization has 19456 authors who have published 33659 publications receiving 365676 citations.

A computational framework for propagated waves in a sandwich doubly curved nanocomposite panel

Abstract: In the current report, characteristics of the propagated wave in a sandwich structure with a soft core and multi-hybrid nanocomposite (MHC) face sheets are investigated. The higher-order shear deformable theory (HSDT) is applied to formulate the stresses and strains. Rule of the mixture and modified Halpin–Tsai model are engaged to provide the effective material constant of the multi-hybrid nanocomposite face sheets of the sandwich panel. By employing Hamilton’s principle, the governing equations of the structure are derived. Via the compatibility rule, the bonding between the composite layers and a soft core is modeled. Afterward, a parametric study is carried out to investigate the effects of the CNTs' weight fraction, core to total thickness ratio, various FG face sheet patterns, small radius to total thickness ratio, and carbon fiber angel on the phase velocity of the FML panel. The results show that the sensitivity of the phase velocity of the FML panel to the $${W}_{\rm{CNT}}$$ and different FG face sheet patterns can decrease when we consider the core of the panel more much thicker. It is also observed that the effects of fiber angel and core to total thickness ratio on the phase velocity of the FML panel are hardly dependent on the wavenumber. The presented study outputs can be used in ultrasonic inspection techniques and structural health monitoring.

Role of gut microbiota in the pathogenesis of colorectal cancer; a review article.

Abstract: Colorectal cancer (CRC) is one of the most frequently diagnosed cancers worldwide. Lifestyle is identified as one of the most important risk factors for CRC, especially in sporadic colorectal cancer. The natural composition of the gut microbiota changes rapidly during the first decade of life. Maintaining homeostasis in the gut is essential as structural and metabolic functions of the commensal microbiota inhibit gut colonization of pathogens. Dysbiosis, imbalance in function or structure of gut microbiota, has been associated with a variety of diseases, such as colorectal cancer. The aim of this review was to investigate the possible links between the dysbiosis in gut microbiota and colorectal cancer, and the potential role of anaerobic gut microbiota in the pathogenesis of colorectal cancer. Based on this review, various studies have shown that some of the gut microbiota such as anaerobic bacteria significantly increased in CRC patients, but we suggest more investigations are required to assess the importance of these bacteria and their metabolites in the pathogenesis of CRC are required.

Toxicity Effect of Silver Nanoparticles on Mice Liver Primary Cell Culture and HepG2 Cell Line

Abstract: Nano-silver (AgNP) has biological properties which are significant for consumer products, food technology, textiles and medical applications (e.g. wound care products, implantable medical devices, in diagnosis, drug delivery, and imaging). For their antibacterial activity, silver nanoparticles are largely used in various commercially available products. Thus, the use of nano-silver is becoming more and more widespread in medicine. In this study we investigated the cytotoxic effects of AgNPs on liver primary cells of mice, as well as the human liver HepG 2 cell. Cell viability was examined with MTT assay after HepG 2 cells exposure to AgNPs at 1, 2, 3, 4, 5, 7.5, 10 ppm compared to mice primary liver cells at 1, 10, 50, 100, 150, 200, 400 ppm for 24 h. AgNPs caused a concentration-dependent decrease of cell viability in both cells. IC 50 value of 2.764 ppm (µg/mL) was calculated in HepG 2 cell line and IC 50 value of 121.7 ppm (µg/mL) was calculated in primary liver cells of mice. The results of this experiment indicated that silver nanoparticles had cytotoxic effects on HepG 2 cell line and primary liver cells of mice. The results illustrated that nano-silver had 44 times stronger inhibitory effect on the growth of cancerous cells (HepG 2 cell line) compared to the normal cells (primary liver cells of mice). Which might further justify AgNPs as a cytotoxic agents and a potential anticancer candidate which needs further studies in this regard.