Damage mechanics model for fracture process of steel-concrete composite slabs

Composite slab construction using permanent cold-formed steel decking has become one of the most economical and industrialized forms of flooring systems in modern building structures. Structural performance of the composite slab is affected directly by the horizontal shear bond phenomenon at steel-concrete interface layer. This study utilizes 3D nonlinear finite element quasistatic analysis technique to analyze the shear bond damage and fracture mechanics of the composite slabs. Fracture by opening and sliding modes of the plain concrete over the corrugated steel decking had been modeled with concrete damaged plasticity model available in ABAQUS/Explicit module. The horizontal shear bond was simulated with cohesive element. Cohesive fracture properties such as fracture energy and initiation stress were derived from horizontal shear bond stress versus end slip curves. These curves were extracted from bending tests of narrow width composite slab specimens. Results of the numerical analyses match the experimental results accurately. This study demonstrated that the proposed finite element model and analysis procedure can predict the behavior of composite slabs accurately. The procedure can be used as a cheaper alternative to experimental work for investigating the ultimate strength and actual fracture and damage behavior of steel-concrete composite slab systems

Green synthesis and chemical characterization of Thymus vulgaris leaf aqueous extract conjugated gold nanoparticles for the treatment of acute myeloid leukemia in comparison to doxorubicin in a leukemic mouse model

Recently, metallic nanoparticles have been used for the treatment of several disorders, such as cancer. Indeed, finding the chemotherapeutic drug of nanoparticles is in researching the priority of both developed and developing countries. The present study confirms the ability of aqueous extract of Thymus vulgaris grown under in vitro condition for the biosynthesis of gold nanoparticles (AuNPs). Also, in this study, we indicated the antioxidant, cytotoxicity, and anti-acute myeloid leukemia properties of AuNPs compared to doxorubicin in a leukemic mouse model. The synthesized AuNPs were characterized using different techniques including X-ray diffraction (XRD), energy Dispersive X-ray Spectrometry (EDS), fourier-transform infrared spectroscopy (FT-IR) spectroscopy, ultraviolet-visible spectroscopy (UV-Vis.), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). In vivo design, induction of acute myeloid leukemia was done by 7,12-Dimethylbenzaanthracene (DMBA) in 75 mice. Then, the animals were randomly divided into six subgroups, including control, untreated, doxorubicin, AuNPs, T. vulgaris, and HAuCl4. By quantitative real-time PCR, sphingosine-1-phosphate receptor-1 and sphingosine-1-phosphate receptor-5 mRNA expression in lymphocytes were significantly (P <= 0.01) raised by treating the leukemic mice with the AuNPs and doxorubicin. Also, AuNPs similar to doxorubicin, significantly (P <= 0.01) enhanced the anti-inflammatory cytokines (IL4, IL5, IL10, IL13, and IFN alpha) and the platelet, lymphocyte, and red blood cell (RBC) parameters and reduced the pro-inflammatory cytokines (IL1, IL6, IL12, IL18, IFNY, and TNF alpha), and the total white blood cell (WBC), blast, monocyte, neutrophil, eosinophil, and basophil counts as compared to the untreated mice. In vitro design, 2,2-diphenyl-1-picrylhydrazyl (DPPH) test revealed similar antioxidant potentials for doxorubicin and AuNPs. Furthermore, AuNPs similar to doxorubicin had low cell viability dose-dependently against 32D-FLT3-ITD, Human HL-60/vcr, and Murine C1498 cell lines without any cytotoxicity on HUVEC cell line. Above results confirm the excellent antioxidant, cytotoxicity, and anti-acute myeloid leukemia effects of AuNPs compared to doxorubicin. After confirming these results in clinical trial studies, AuNPs can be used as a chemotherapeutic drug for the treatment of acute myeloid leukemia in human

Green synthesis of gold nanoparticles using potato starch as a phytochemical template, green reductant and stabilizing agent and investigating its cytotoxicity, antioxidant and anti-ovarian cancer effects

Herein we have demonstrated a sustainable pathway for the Au nanoparticles synthesis using potato starch as a phytochemical template, green reductant and stabilizing agent. The reaction was initiated by ultrasound irradiation as a non-conventional source of energy. As-synthesized nanocomposite material (Starch/Au NPs) physicochemical characteristics was determined over several analytical techniques like TEM, UV-Vis, SEM, XRD and EDX. The in vitro cytotoxic and anti-ovarian potentials of biologically synthesized Starch/Au nanocomposite were assessed against OVCAR-3 and OVCAR-4 cancer cells. The anti-ovarian cancer activities of the Starch/Au nanocomposite were validated by the significant diminishing of OVCAR-3 and OVCAR-4 cancer cells. The IC50 of the Starch/Au nanocomposite were found as 285 and 189 & mu;g/mL respectively against the said cell lines. The outstanding results of this current research definitely could lead the biologically synthesized Starch/Au nancomposite as a potential adjuvant chemopreventive and chemotherapeutic agent to cure the ovarian cancer. The material also exhibited significant antioxidant properties. However, it necessitates in vivo animal studies to ascertain further evidences as anti-ovarian cancer agents