Viscoelastic wave–ice interactions: a computational fluid–solid dynamic approach

A computational fluid–solid dynamic model is employed to simulate the interaction between water waves and a consolidated ice cover. The model solves the Navier–Stokes equations for the ocean-wave flow around a solid body, and the solid behavior is formalized by the Maxwell viscoelastic model. Model predictions are compared against experimental flume tests of waves interacting with viscoelastic plates. The decay rate and wave dispersion predicted by the model are shown to be in good agreement with experimental results. Furthermore, the model is scaled, by simulating the wave interaction with an actual sea ice cover formed in the ocean. The scaled decay and dispersion results are found to be still valid in full scale. It is shown that the decay rate of waves in a viscoelastic cover is proportional to the quadratic of wave frequency in long waves, whilst biquadrate for short waves. The former is likely to be a viscoelastic effect, and the latter is likely to be related to the energy damping caused by the fluid motion. Overall, the modeling approach and results of the present paper are expected to provide new insights into wave–ice interactions and help researchers to dynamically simulate similar fluid–structure interactions with high fidelity

Prevalence of PER and VEB Type Extended Spectrum Betalactamases among Multidrug Resistant Acinetobacter baumannii Isolates in North-West of Iran

Objective(s): Drug resistant Acinetobacter baumannii have emerged as a major problem in many hospitals and intensive care units. Various types of extended spectrum beta-lactamases (ESBLs) are responsible for resistance to beta-lactam antibiotics in different parts of the world. The objective of this study was to determine the prevalence of integron class1 (INT 1) and ESBL types PER-1, PER-2 and VEB-1 among A. baumannii strains isolated from Tabriz, North-West of Iran

The role of the serum exosomal and endometrial microRNAs in recurrent implantation failure

It has been identified that endometrium specific microRNAs have different expression levels in endometrial tissues and maternal serum during endometrial cycle. The aim of this study was to analyze microRNA expression levels in recurrent implantation failure patients and healthy controls endometrial samples for enlightening the aetiopathogenesis of the disease. The second aim was to search for a potential noninvasive molecular biomarker in early diagnosis and treatment of Recurrent Implantation Failure (RIF) patients

Antimicrobial Susceptibility Pattern and Prevalence of Extended-Spectrum beta-Lactamase Genotypes among Clinical Isolates of Acinetobacter baumanii in Tabriz, North-West of Iran

Background: Multidrug resistant (MDR) Acinetobacter baumanii strains have emerged as novel nosocomial pathogens threatening patients' lives, especially in intensive-care units (ICU). Various types of extended-spectrum beta-lactamases (ESBLs) are involved in conferring resistance to beta-lactam antibiotics, making their genotypic characterization an essential prerequisite to take proper preventative measures

Endometrial gene expression profiling of recurrent implantation failure after in vitro fertilization

Recurrent implantation failure (RIF) is diagnosed when good-quality embryos repeatedly fail to implant after transfer in several in vitro fertilization (IVF) treatment cycles. Different expression profiles in maternal mRNAs could be referring to many diseases including RIF. This study aimed to reveal significantly dysregulated selected genes expression between healthy fertile women and RIF patients in the implantation window days of the natural menstrual cycle. MME, WWC1, TNC, and FOXP3 genes were chosen as target genes regarding their possible relations with the implantation process. Pathways with these genes were identified and the relationship between these pathways and RIF was investigated. In this study, the endometrial biopsy samples were collected in the secretory phase (cycle day 20-24) of the menstrual cycle from RIF patients (n = 34) and healthy fertile controls (n = 34). After "Pathway and network-oriented GWAS analysis" (PANOGA) and "Kyoto Encyclopedia of Genes and Genomes" (KEGG) pathway analysis; "Membrane Metalloendopeptidase" (MME), "WW and C2 Domain Containing 1" (WWC1), "Tenascin C" (TNC) and "Forkhead Box P3" (FOXP3) genes were chosen as target genes by regarding their possible relation with implantation process. Detection of differences in mRNA expressions between the control group and RIF patients has been performed with the droplet digital PCR (ddPCR) method. Results of the study showed that MME and WWC1 genes expression levels are significantly (p < 0,05) up-regulated 4.9 and 5.2 times respectively and TNC gene expression level is significantly (p < 0,05) down-regulated 9 times in the RIF samples compared to the control group. However, no statistically significant difference was observed between the patient group and the control group in the expression of the FOXP3 gene (p < 0.05). Changes are observed in the expression of the renin-angiotensin system pathway in which the MME gene is involved in the implantation process. The increase in MME gene expression can be speculated to cause implantation failure by restricting the invasion of trophoblast cells. Increasing WWC1 gene expression in the Hippo signaling pathway inhibits "Yes-associated protein 1" (YAP) expression, which is a transcriptional cofactor. Inhibition of YAP protein expression may impair the implantation process by causing the failure of endometrial decidualization. The TNC gene is located in the focal adhesion pathway and this pathway reduces cell adhesion on the endometrial surface to facilitate the attachment of the embryo to the endometrium. The reason for implantation failure might be that the intercellular connections are not suitable for implantation as a result of decreased expression of the focal adhesion pathway in which the TNC gene is effective. Considering the relations between the pathways of the target genes and the implantation process, changes in the expression of target genes might be a cause of RIF