Application of a Cosserat Continuum Model to Non-associated Plasticity

A severe, spurious dependence of numerical simulations on the mesh size and orientation can be observed in elasto-plastic models with a non-associated flow rule. Such mesh dependency effects are quite well-known and vastly investigated in problems with the presence of strain softening in the constitutive relation. However, other material instabilities, like non-associated plastic flow, can also cause mesh sensitivity. Indeed, loss of well-posedness of the problem in quasi-static analyses is the fundamental cause of the observed mesh dependence. It has been known since long that non-associated plastic flow can cause loss of stability, but the consequence for mesh sensitivity, and subsequently, for the difficulty of the equilibrium-finding iterative procedure to converge, have remained largely unnoticed. The present thesis deals with exploring the possibility of using non-standard continua, namely the Cosserat continuum models, in non-associated plasticity problems to tackle the pathological mesh dependencies not only on the size of the elements but also on the orientation of them. The motivation in this thesis for using the Cosserat continuum models for this purpose, lies in the additional parameters that are specified in such a model, i.e. the micro-rotations and characteristic length scale. These features make the Cosserat continuum model a suitable choice to simulate and capture the behavior of the granular and geomaterials. The characteristic length scale helps regularise the strain localisation problems and prevent loss of uniqueness of solution. The mesh size dependency of the results for classical non-associated plasticity models is analysed in depth using an infinitely long shear layer. It is shown that the mesh effect disappears when the standard continuum model is replaced by a Cosserat continuum. Next, the dependence of the shear-band inclination in a biaxial test on the mesh size as well as on the mesh orientation is investigated. The orientation of the developed shear band is found to be dependent on the orientation of the mesh for classical models. Using a Cosserat continuum model, numerical solutions result for shear-band formation which are independent of the size and the orientation of the discretisation

Comparative antibacterial effects of ginger and marjoram extract versus conventional irrigants on mature Enterococcus faecalis biofilms : an in vitro study

This study evaluated antibacterial effects of Ginger and Marjoram extract compared with Routine Intracanal Irrigants on Mature Enterococcus faecalis Biofilms. Sixty-six extracted human teeth, were randomly assigned to four groups 5.25% sodium hypochlori

Analyzing Interface Bonding Schemes for VLC with Mobility and Shadowing

Node mobility and shadowing are the most common reasons requiring a handover in vehicular visible light communications (VVLC). In order to provide seamless mobility during the handover, it is required to decrease the network outage duration. This paper aims to improve the outage duration in handover caused by mobility and shadow for VLC networks. We analyze interface bonding schemes using two different primary interface reselection methods. The results show that using "failure"interface selection method instead of "always"method reduces the VLC handover outage duration by 62% and 44% in bonding schemes for transmission control protocol (TCP) and user datagram protocol (UDP) network traffic, respectively

Levels of Blood Biomarkers among Patients with Myocardial Infarction in Comparison to Control Group

BACKGROUND: Myocardial infarction (MI) as a term for a heart attack happens due to reduced blood flow to heart myocardium and lack of oxygen supply caused by plaques inthe interior walls of coronary arteries. With respect to the importance of MI etiology, we aimed to study the relationship of MI and blood examination variables.METHODS: This study was conducted in Mazandaran Heart Center as a hospital-based case-control Comprising 894 participants including 465 cases and 429 controls, individually matched by sex and age. Considered blood markers were analyzed using routine laboratory methods and equipment.RESULTS: Of all participants, 64.3% of the cases and 51.0% of the controls were males with a mean age of 61.2 (±13.8) in cases and 62.4 (±14.) in controls. We could not find any differences between cases and controls for total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and alkaline-phosphatase (ALP) (P>0.05). However, levels of creatine-kinase-muscle/brain (CK-MB) (P<0.0001), fasting-blood-sugar (FBS) (P<0.0001), aspartateaminotransferase (AST) (P<0.0001), alanine-transferase (ALT) (P<0.0001) and erythrocyte sedimentation rate (ESR) (P=0.001) were significantly higher in cases compared to the controls (P<0.05). Multivariable analyses revealed that the risk of MI was associated with high levels of AST (adjusted OR=24.3, 95%CI=3.5±165.6, P=0.001) and LDL (adjusted OR=7.4, 95%CI=1.0±51.8, P=0.001).CONCLUSION: Our investigation indicated that the levels of CK-MB, FBS, AST, ALT and ESR were significantly higher in patients with MI. Besides, our findings showed that the risk of MI in cases with high levels of AST and LDL was about 24 and 7 times more than the control group respectively

Circulating and Endometrial Profiles of miR-145, miR-155-5p, miR-224, MPP-5, and PECAM-1 Expression in Patients with Repeated Implantation Failure: A Case Control Study

Objective: An association between microRNAs (miRNAs) and adhesion proteins expression with repeated implantationfailure (RIF) has been recently reported; however, these findings are controversial. This study aims to evaluatethe endometrial and circulating expressions of miR-145, miR-155-5p, and miR-224 in addition to the endometrialexpressions of membrane protein palmitoylated-5 (MPP-5) and endothelial cell adhesion molecule-1 (PECAM-1) inpatients with RIF compared to control subjects.Materials and Methods: This case-control study was carried out between June 2021-July 2022. Subjects included 17patients with RIF and 17 control subjects, who had previous spontaneous term pregnancy with a live birth, who referredto the Medical Centre of Arash Hospital, Tehran, Iran. Endometrial tissue samples were obtained via hysteroscopyand Pipelle catheter in the RIF and control subjects, respectively. Plasma samples were collected after ovulationin all subjects. The expression levels of MPP5, PECAM-1, miR-224, miR-145, and miR-155-5p were evaluated byquantitative real-time polymerase chain reaction (qRT-PCR). The student’s t test, chi-square, Mann-Whitney U, andanalysis of covariance (ANCOVA) were used for data analyses.Results: RIF patients had less endometrial miR-155-5p expression, and higher endometrial and circulating expressions ofmiR-145 and miR-224 compared to control subjects. Endometrial PECAM-1 and MPP5 expression significantly decreased inpatients with RIF compared to the control group. There was a positive correlation between circulating miR-224 and endometrialmiR-155-5p, and between circulating miR-155-5p and endometrial PECAM-1 expression levels in patients with RIF.Conclusion: The present study suggests that circulating miR-224, endometrial miR-145, and PECAM-1 can bereliable, novel biomarkers for diagnosis of RIF

Interactions of Colorectal Cancer, Dietary Fats, and Polymorphisms of Arachidonate Lipoxygenase and Cyclooxygenase Genes: A Literature Review

ObjectiveGenetics and dietary factors play important roles in the development of colorectal cancer (CRC). However, the underlying mechanisms of the interactions between CRC, gene polymorphisms, and dietary fat are unclear. This review study investigated the effects of polymorphisms of arachidonate lipoxygenase (ALOX) and cyclooxygenase (COX) genes in the association between CRC and dietary fat.MethodsAll the related papers published from 2000 to 2022 were collected from different databases such as PubMed, Science Direct, Scopus, and Cochran using related keywords such as colorectal cancer, ALOX, COX, polymorphism, and dietary fat. Non-English and unrelated documents were excluded.ResultsSome single-nucleotide polymorphisms (SNPs) in the ALOX and COX genes, such as rs2228065, rs6413416, and rs4986832 in the ALOX gene, and rs689465 in the COX gene may play significant roles in the association between the risk of CRC and dietary fats. SNPs of ALOX and COX genes may influence the effects of dietary fatty acids on the risk of CRC.ConclusionSome polymorphisms of the ALOX and COX genes may have important roles in the effects of dietary fat on the risk of CRC. If future studies confirm these results, dietary recommendations for preventing colorectal cancer may be personalized based on the genotype of the ALOX and COX genes

IFI27 transcription is an early predictor for COVID-19 outcomes, a multi-cohort observational study

PurposeRobust biomarkers that predict disease outcomes amongst COVID-19 patients are necessary for both patient triage and resource prioritisation. Numerous candidate biomarkers have been proposed for COVID-19. However, at present, there is no consensus on the best diagnostic approach to predict outcomes in infected patients. Moreover, it is not clear whether such tools would apply to other potentially pandemic pathogens and therefore of use as stockpile for future pandemic preparedness.MethodsWe conducted a multi-cohort observational study to investigate the biology and the prognostic role of interferon alpha-inducible protein 27 (IFI27) in COVID-19 patients.ResultsWe show that IFI27 is expressed in the respiratory tract of COVID-19 patients and elevated IFI27 expression in the lower respiratory tract is associated with the presence of a high viral load. We further demonstrate that the systemic host response, as measured by blood IFI27 expression, is associated with COVID-19 infection. For clinical outcome prediction (e.g., respiratory failure), IFI27 expression displays a high sensitivity (0.95) and specificity (0.83), outperforming other known predictors of COVID-19 outcomes. Furthermore, IFI27 is upregulated in the blood of infected patients in response to other respiratory viruses. For example, in the pandemic H1N1/09 influenza virus infection, IFI27-like genes were highly upregulated in the blood samples of severely infected patients.ConclusionThese data suggest that prognostic biomarkers targeting the family of IFI27 genes could potentially supplement conventional diagnostic tools in future virus pandemics, independent of whether such pandemics are caused by a coronavirus, an influenza virus or another as yet-to-be discovered respiratory virus

Investigation of multi-scale modeling strategies to simulate high velocity impact damage

The presentthesis deals with setting up computationally efficient muli-scale finite element (FE) models for simulation of impact problems in industrial applications. In particular, the main focus is to introduce and investigate possible mesh-matching techniques in the FE explicit code PAM-CRASH to be used at the boundaries of non-conform meshes. Two methods, namely multi-point constraint and a contact-type tied interface are investigated in a low-complexity model under quasi-static loading. Due to superiority of tied interface method in sense of convenience of application, this method is selected to be investigated further in multi-scale simulations of low-velocity impact of hard object on a CFRP laminated plate and high velocity impact of a soft body on a C-frame stiffened composaite panel. As the outcome of teh study, tied interface method in multi-scale FE-models proved to reproduce sufficiently accurate global responses as well as delamination in the impact zone compared to test data

Understanding the Relationship between Microstructure and Physicochemical Properties of Ultrafiltered Feta-Type Cheese Containing Saturea bachtiarica Leaf Extract

Microwave-assisted extraction was optimized to prepare Satureja bachtiarica leaf (SBL) extract based on antimicrobial (IZD) and antioxidant activities (DPPH) and extraction yield (EY). At optimum condition, i.e., 800 W power and 8 min, the best extraction results with EY = 16%, IZD = 73.56 mm, and DPPH = 24.2% were obtained. To develop a novel Feta-cheese, the influence of SBL extract, rennet, and starter concentrations were evaluated in terms of rheological, textural, and sensorial properties. At the optimized condition, the acceptance, taste, the strength of the network (A), and the distance between sequential cross-linking points (ξ) were 8.13, 8.07, 34,036.12 Pa·s1/z, and 5.41 nm, respectively. At the 60th day of storage time, the lowest z value (the network extensity parameter) of the cheese samples was observed. SEM image texture indices showed a good correlation with the studied instrumental texture parameters during 60 days of storage. The mold and yeast counts and their growth rate in the SBL extract-added cheese were lower than those for control one; whereas, the former cheese showed a greater LAB population between the 80th and 120th days. The antimicrobial and antioxidant qualities of SBL extract showed a significant influence on cheese properties

A polynomial analog baseband predistorter for compensation of wireless amplifier’s distortion

This paper presents a new analog polynomial pre-distortion circuit using 350nm CMOS technology to reduce the distortion of the power amplifier in wireless communication systems. The proposed pre-distortion circuit uses the polynomial approach. The coefficients of the polynomial are controlled by multiplying them with sufficient digit defined through the indirect learning process to provide best practice linearization. Circuit level simulation of the proposed circuit is using Cadence DFW II is used as proof of concept. The simulation set-up comprises a power amplifier, excited with a four carrier GSM signal, pre-distorted by the proposed circuit. Simulation results show that using the pre-distortion circuit the 3rd order intermodulation distortion is reduced on average by 12 and 16 dB.publishe