Effect of layer angle and ambient temperature on the mechanical and fracture characteristics of unidirectional 3D printed PLA material

This study aims to investigate the mechanical properties and crack resistance of unidirectional polylactic acid-based 3D printed components. In this regard, the effects of three printing angles (e.g., 0°, 45°, and 90°) and four ambient temperatures (e.g., −20, 0, 20, and 40 °C) on the tensile, flexural, and mode-I fracture characteristics were investigated. Additionally, utilizing theoretical theories appropriate for 3D printed samples as transversely isotropic samples, the results were assessed and expanded. Using the concepts of inlayer and interlayer failure modes in layered samples, the critical printing angle that separates the failure modes were evaluated. Also, failure patterns and the behavior of load-displacement curves were observed and assessed. The results show that an increase in temperature from − 20–40 °C caused tensile strength to decrease by 55–75%. Considering the samples isotropically, the strengths and energies were compared, then considering the anisotropy, inlayer, and interlayer tensile and shear strengths were reviewed. The results show that perpendicularly and transitively printed specimens have tensile strengths that are 4.4 and 2.5 times lower than parallel to loading direction printed specimens. Also, the critical printing angle is calculated as 23–31° based on the test temperature (respecting the load direction)

Simultaneous doxorubicin encapsulation and in-situ microfluidic micellization of bio-targeted polymeric nanohybrids using dichalcogenide monolayers : A molecular in-silico study

The rate of Riboflavin (RF) consumption in cancerous cells is interestingly high and this might imply the use of RF ligand in nanocarriers in order to target anticancer drugs into cancer cells. This study aimed to develop a hybrid drug carrier of Doxorubicin (DOX) loaded on RF targeted micelles composed of hydrophobic polylacticglycolic acid (PLGA) and hydrophilic polyethylene glycol (PEG). In this regard, a simultaneous encapsulation of DOX and in-situ micellization as well as the self-assembly of PLGA-PEG-RF molecules were investigated. Moreover, the effects of microfluidic environment and transition metal dichalcogenide (TMD) nanolayers on the micellization properties (e.g., stability, size, and self-assembly interaction energies) of nanocarriers were simulated for the first time. To this purpose, the simulations were performed using two non-microfluidic methods as well as a novel microfluidic one. The molecular simulations revealed that all of the selected TMDs, especially MoSe2, had a great impact on the stability and size of nanocarriers. MoSe2 significantly enhanced the loading capacity as well as the stability of RF-targeted micelles and reduced the size of nanocarriers. Likewise, the results of various analyses demonstrated that the microfluidic method is the most effective way to synthesize nano carriers with higher stability and smaller particle size. Hence, the use of MoSe2 monolayer, micelle containing RF, and microfluidic method were believed to be the best approach in order to improve the quality of micelles. The present work sheds new light on the use of TMDs in the synthesis of smart carriers for cancer treatment.Peer reviewe

Engineering of 2D nanomaterials to trap and kill SARS-CoV-2 : a new insight from multi-microsecond atomistic simulations

In late 2019, coronavirus disease 2019 (COVID-19) was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Spike protein is one of the surface proteins of SARS-CoV-2 that is essential for its infectious function. Therefore, it received lots of attention for the preparation of antiviral drugs, vaccines, and diagnostic tools. In the current study, we use computational methods of chemistry and biology to study the interaction between spike protein and its receptor in the body, angiotensin-I-converting enzyme-2 (ACE2). Additionally, the possible interaction of two-dimensional (2D) nanomaterials, including graphene, bismuthene, phosphorene, p-doped graphene, and functionalized p-doped graphene, with spike protein is investigated. The functionalized p-doped graphene nanomaterials were found to interfere with spike protein better than the other tested nanomaterials. In addition, the interaction of the proposed nanomaterials with the main protease (M-pro) of SARS-CoV-2 was studied. Functionalized p-doped graphene nanomaterials showed more capacity to prevent the activity of M-pro. These 2D nanomaterials efficiently reduce the transmissibility and infectivity of SARS-CoV-2 by both the deformation of the spike protein and inhibiting the M-pro. The results suggest the potential use of 2D nanomaterials in a variety of prophylactic approaches, such as masks or surface coatings, and would deserve further studies in the coming years.Peer reviewe

Ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br): a green and neutral reaction media for the efficient, catalyst-free synthesis of quinoxaline derivatives

Quinoxaline derivatives were produced in excellent yields and short reaction times via the condensation of 1,2-diamines with 1,2-diketones in the neutral ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) under catalyst-free and microwave irradiation conditions

Experimental and Computational Study on the Microfluidic Control of Micellar Nanocarrier Properties

Microfluidic-based synthesis is a powerful technique to prepare well-defined homogenous nanoparticles (NPs). However, the mechanisms defining NP properties, especially size evolution in a microchannel, are not fully understood. Herein, microfluidic and bulk syntheses of riboflavin (RF)-targeted poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG-RF) micelles were evaluated experimentally and computationally. Using molecular dynamics (MD), a conventional "random"model for bulk self-assembly of PLGA-PEG-RF was simulated and a conceptual "interface"mechanism was proposed for the microfluidic self-assembly at an atomic scale. The simulation results were in agreement with the observed experimental outcomes. NPs produced by microfluidics were smaller than those prepared by the bulk method. The computational approach suggested that the size-determining factor in microfluidics is the boundary of solvents in the entrance region of the microchannel, explaining the size difference between the two experimental methods. Therefore, this computational approach can be a powerful tool to gain a deeper understanding and optimize NP synthesis. © 2021 The Authors. Published by American Chemical Society

Morphine Attenuated the Cytotoxicity Induced by Arsenic Trioxide in H9c2 Cardiomyocytes.

Arsenic trioxide (ATO) is an efficient drug for the treatment of the patients with acute promyelocytic leukemia (APL). Inhibition of proliferation as well as apoptosis, attenuation of migration, and induction of differentiation in tumor cells are the main mechanisms through which ATO acts against APL. Despite advantages of ATO in treatment of some malignancies, certain harmful side effects, such as cardiotoxicity, have been reported. It has been well documented that morphine has antioxidant, anti-apoptotic, and cytoprotective properties and is able to attenuate cytotoxicity. Therefore, in this study, we aimed to investigate the protective effects of morphine against ATO toxicity in H9c2 myocytes using multi-parametric assay including thiazolyl blue tetrazolium bromide (MTT) assay, reactive oxygen species (ROS) generation, caspase 3 activity, nuclear factor kappa B (NF-κB) phosphorylation assay, and expression of apoptotic markers. Our results showed that morphine (1 μM) attenuated cytotoxicity induced by ATO in H9c2 cells. Results of this study suggest that morphine may have protective properties in management of cardiac toxicity in patients who receive ATO as an anti-cancer treatment

Psychometric Properties of the Cornell Scale for Depression in Dementia in Elderly Individuals with Dementia in Isfahan, Iran

Introduction: Depression is the second most prevalent psychological disorder in the elderly. This study was designed to evaluate the psychometric properties of the Cornell Scale for Depression in Dementia (CSDD) in the elderly population afflicted with dementia in Isfahan, Iran. Materials and Methods: This psychometric study was performed on 110 elderly individuals who were selected randomly from among individuals who were referred to the elderly clinic of Isfahan and were diagnosed as a case of dementia based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) criteria. All participants completed the CSDD, Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS). The collected data were analyzed descriptive statistics, Cronbach’s alpha, factor analysis, and the Pearson correlation coefficient in SPSS software. Results: Total scale reliability coefficient was 0.85 and the reliability of the factors of depression, psychotic depressive symptoms, sleep disorders, somatic symptoms, and anxiety was 0.77, 0.63, 0.79, 0.62, and 0.47, respectively. The correlation coefficient of GDS and MMSE with total scale of CSDD was obtained as 0.47 (P < 0.01) and 0.35 (P < 0.10), respectively, using the Pearson coefficient. Exploratory factor analysis showed that the 5 abovementioned extracted factors had common variance of 58.72%. Conclusion: The Persian version of CSDD contained acceptable psychometric properties in this sample of Iranian elderly individuals with dementia

β-Amyloid Targeting with Two-Dimensional Covalent Organic Frameworks : Multi-Scale In-Silico Dissection of Nano-Biointerface

Cytotoxic aggregation of misfolded beta-amyloid (A beta) proteins is the main culprit suspected to be behind the development of Alzheimer's disease (AD). In this study, A beta interactions with the novel two-dimensional (2D) covalent organic frameworks (COFs) as therapeutic options for avoiding beta-amyloid aggregation have been investigated. The results from multi-scale atomistic simulations suggest that amine-functionalized COFs with a large surface area (more than 1000 m(2)/gr) have the potential to prevent A beta aggregation. Gibb's free energy analysis confirmed that COFs could prevent protofibril self-assembly in addition to inhibiting beta-amyloid aggregation. Additionally, it was observed that the amine functional group and high contact area could improve the inhibitory effect of COFs on A beta aggregation and enhance the diffusivity of COFs through the blood-brain barrier (BBB). In addition, microsecond coarse-grained (CG) simulations with three hundred amyloids reveal that the presence of COFs creates instability in the structure of amyloids and consequently prevents the fibrillation. These results suggest promising applications of engineered COFs in the treatment of AD and provide a new perspective on future experimental research.Peer reviewe

Physico-chemical characterization and anti-laryngeal cancer effects of the gold nanoparticles

Most recently, gold nanoparticles due to anticancer properties have been considered in medical science. So the aim of the study was green synthesis of gold nanoparticles using Ocimum basilicum extract and its anticancer activity. The prepared Au nanoparticles were characterized by advanced physicochemical techniques like Fourier Transformed Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD) and UV–vis spectroscopy study. It has been established that Au nanoparticles have a spherical shape with a mean diameter from 19 to 44 nm. In the cellular and molecular part of the recent study, the treated cells with Au nanoparticles were assessed by MTT assay for 48 h about the cytotoxicity and anti-human laryngeal cancer properties on normal (HUVEC) and cancer (HEp-2, TU212, KB, UM-SCC-5, UM-SCC-11A and UM-SCC-11B) cell lines. In the antioxidant test, the IC50 of Au nanoparticles and BHT against DPPH free radicals were 228 and 208 µg/mL, respectively. The IC50 of Au nanoparticles were 174, 231, 179, 143, 230, and 216 µg/mL against HEp-2, TU212, KB, UM-SCC-5, UM-SCC-11A and UM-SCC-11B cell lines, respectively. The viability of malignant cell lines reduced dose-dependently in the presence of Au nanoparticles. It appears that the anti-cancer effect of Au nanoparticles e to their antioxidant effects