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 & Cancer. The organization has 19456 authors who have published 33659 publications receiving 365676 citations.

Energy gap opening in submonolayer lithium on graphene: Local density functional and tight-binding calculations

Abstract: The adsorption of an alkali-metal submonolayer on graphene occupying every third hexagon of the honeycomb lattice in a commensurate $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R30\ifmmode^\circ\else\textdegree\fi{}$ arrangement induces an energy gap in the spectrum of graphene. To exemplify this type of band gap, we present ab initio density functional theory calculations of the electronic band structure of ${\text{C}}_{6}\text{Li}$. An examination of the lattice geometry of the compound system shows the possibility that the nearest-neighbor hopping amplitudes have alternating values constructed in a Kekul\'e-type structure. The band structure of the textured tight-binding model is calculated and shown to reproduce the expected band gap as well as other characteristic degeneracy removals in the spectrum of graphene induced by lithium adsorption. More generally we also deduce the possibility of energy gap opening in periodic metal on graphene compounds ${\text{C}}_{x}M$ if $x$ is a multiple of 3.

Design and fabrication of GelMA/chitosan nanoparticles composite hydrogel for angiogenic growth factor delivery

Abstract: The cellular microenvironment plays a crucial role in improving cell response and function of an engineered tissue. Scaffolds mimicking the native ECM and capable of releasing growth factors are great candidates for tissue engineering applications. Gelatin methacryloyl (GelMA) hydrogel, a photocrosslinkable biomaterial possessing tunable properties, has been widely used in tissue engineering. It has been suggested that incorporating micro/nano carriers in GelMA could provide a sustained release of growth factors. Specifically, chitosan nanoparticles can be used for growth factor delivery due to its biocompatibility, easy method of synthesis, and preventing the biomolecule from degradation. In this study, GelMA/chitosan nanoparticles composite hydrogel was developed to deliver an angiogenic growth factor (bFGF). The hydrogel was prepared by photopolymerization and its chemical and physical properties were characterized. Its degradation and swelling characteristics were also evaluated. The size of nanoparticles was evaluated and the profile of bFGF release from the hydrogel and its effect on the viability of fibroblast cells was studied. The results showed that GelMA/chitosan nanoparticles can significantly promote cell proliferation due to its biocompatible structure and providing a sustained profile of bFGF release. This hydrogel scaffold can be used for efficient delivery of bFGF in various applications and especially for angiogenesis.

Effect of low level laser therapy on proliferation and differentiation of the cells contributing in bone regeneration.

Abstract: Introduction: Low level laser therapy (LLLT) also known as photobiomodulation, is a treatment that uses low-level lasers or light-emitting diodes (LEDs) to change cellular function and is a clinically well accepted tool in regenerative medicine and dentistry. Considering the variety of laser, exposure, cells and study types, the exact effects of low level laser therapy seems to be unclear. The aim of this study was to review the data published in the field of the effects of low level laser therapy on proliferation and differentiation of the cells contributing in bone regeneration. Methods: To access relevant articles, an electronic search in PubMed was conducted from 2001 to April 2014. English language published papers on low level laser therapy were found using the selected keywords .The full texts of potentially suitable articles were obtained for final assessment according to the exclusion and inclusion criteria. Results: 240 articles were found from 2001 to April 2014. Following the initial screening of titles and abstracts as well as the final screening of full texts, 22 articles completely fulfilled the inclusion criteria of this study. Wavelength used in LLLT irradiation varied between 600 to 1000 nm with an energy density of 0.04–60J/cm2 . Although almost all studies agreed on getting positive effects from LLLT, some had opposing results. Conclusion: Low level laser with low-energy density range appears to exert a biostimulatory effect on bone tissue, enhance osteoblastic proliferation and differentiation on cell lines used in in vitro studies. Despite the fact that many researches have been recently done on the effects of LLLT on different cell lines, without knowing the precise mechanism and effects, we are not able to offer a clinical treatment protocol. This paper is a beginning to help further progress and extend practical use of LLLT in future.

The microbiome and breast cancer: a review.

Abstract: The human microbiome plays an integral role in physiology, with most microbes considered benign or beneficial. However, some microbes are known to be detrimental to human health, including organisms linked to cancers and other diseases characterized by aberrant inflammation. Dysbiosis, a state of microbial imbalance with harmful bacteria species outcompeting benign bacteria, can lead to maladies including cancer. The microbial composition varies across body sites, with the gut, urogenital, and skin microbiomes particularly well characterized. However, the microbiome associated with normal breast tissue and breast diseases is poorly understood. Collectively, studies have shown that breast tissue has a distinct microbiome with particular species enriched in the breast tissue itself, as well as the nipple aspirate and gut bacteria of women with breast cancer. More importantly, the breast and associated microbiomes may modulate therapeutic response and serve as potential biomarkers for diagnosing and staging breast cancer.

Emerging Theranostic Biogenic Silver Nanomaterials for Breast Cancer: A Systematic Review

Abstract: Breast cancer remains the second common cause of cancer death in United State women in 2018. Consequently, it is of growing need to explore new strategies to treat cancer at various stages of breast cancer. This review discussing the efficacy of biogenic silver nanoparticles (AgNPs) against breast cancer and/or normal cells and its mechanisms of AgNPs toxicity. The research articles were systematically collected through databases including Cochrane, Web of Science, PubMed, Scopus, Science Direct, ProQuest, Google Scholar, and Embase. Significantly, most of the studies were carried out on MCF-7 cancer cell line. Furthermore, the general approach was phyto-fabrication of AgNPs. Specifically, a hefty 71.27% of studies employed plants to bio-fabricate AgNPs. Additionally, fungi with 14.89% of the studies were the second predominant resources conducted for synthesis of AgNPs. Majority of studies bio-fabricated spherical AgNPs with an average diameter of less than 100 nm. Interestingly, the general approach suggested significant toxic effects of biogenic AgNPs with inhibitory concentration of 50% in breast cancer cell lines, while less toxicity was reported in normal cell lines. Regarding the recent advantages in cancer nanomedicine, it is expected that biogenic AgNPs may emerge as potential breast cancer therapeutic agents alone or in combination with FDA-approved anti-cancer drugs in the near future.