Optimum range of angle tracking radars: a theoretical computing

In this paper, we determine an optimal range for angle tracking radars (ATRs) based on evaluating the standard deviation of all kinds of errors in a tracking system. In the past, this optimal range has often been computed by the simulation of the total error components; however, we are going to introduce a closed form for this computation which allows us to obtain the optimal range directly. Thus, for this purpose, we firstly solve an optimization problem to achieve the closed form of the optimal range (Ropt.) and then, we compute it by doing a simple simulation. The results show that both theoretical and simulation-based computations are similar to each other

EFL paraphrasing skills with QuillBot: Unveiling students' enthusiasm and insights

EFL students' attitudes are crucial for the development of writing abilities, which in the age of cutting-edge technology depend extensively on artificial intelligence -mediated tools, and paraphrasing draws no exception. Therefore, this study aims to identify English as a foreign language student’s enthusiasm and insights about utilizing QuillBot to improve their paraphrasing skills. To achieve the study objectives, the quasi-experimental design was employed. Thirty-one preparatory year students were recruited to answer a questionnaire and semi-structured interview having verified the validity and reliability of the instruments. The sample of the test demonstrated that students improved their performance in synonyms, sentence structure, and word choice. The respondents hold high enthusiasm and insights toward utilizing QuillBot to improve their paraphrasing skills. In addition, students had positive feelings about utilizing QuillBot to improve their paraphrasing skills. In light of the findings, the researchers recommended employing QuillBot in a writing class while learning paraphrasing skills

Evaluation of the effect of hypericum triquetrifolium turra on memory impairment induced by chronic psychosocial stress in rats: Role of BDNF

Background: Chronic psychosocial stress impairs memory function and leads to a depression-like phenotype induced by a persistent status of oxidative stress. Hypericum perforatum L. (St. John’s wort) is widely used to relieve symptoms of anxiety and depression; however, its long-term use is associated with adverse effects. Hypericum triquetrifolium Turra is closely related to H. perforatum. Both plants belong to Hypericaceae family and share many biologically active compounds. Previous work by our group showed that methanolic extracts of H. triquetrifolium have potent antioxidant activity as well as high hypericin content, a component that proved to have stress-relieving and antidepressant effects by other studies. Therefore, we hypothesized that H. triquetrifolium would reduce stress-induced cognitive impairment in a rat model of chronic stress. Objective: To determine whether chronic treatment with H. triquetrifolium protects against stress-associated memory deficits and to investigate a possible mechanism. Methods: The radial arm water maze (RAWM) was used to test learning and memory in rats exposed to daily stress using the resident-intruder paradigm. Stressed and unstressed rats received chronic H. triquetrifolium or vehicle. We also measured levels of brain-derived neurotrophic factor (BDNF) in the hippocampus, cortex and cerebellum. Results: Neither chronic stress nor chronic H. triquetrifolium administration affected performance during acquisition. However, memory tests in the RAWM showed that chronic stress impaired different post-encoding memory stages. H. triquetrifolium prevented this impairment. Furthermore, hippocampal BDNF levels were markedly lower in stressed animals than in unstressed animals, and chronic administration of H triquetrifolium chronic administration protected against this reduction. No significant difference was observed in the effects of chronic stress and/or H. triquetrifolium treatment on BDNF levels in the cerebellum and cortex. Conclusion: H. triquetrifolium extract can oppose stress-associated hippocampus-dependent memory deficits in a mechanism that may involve BDNF in the hippocampus

Left Ventricular Assist Device Thrombosis Treated with Intravenous Tissue Plasminogen Activator in a Patient with COVID-19 Infection

Left ventricular assist device (LVAD) implantation is an established treatment for patients with end-stage, systolic heart failure as a bridge to heart transplantation or destination therapy. LVAD pump thrombosis is a life-threatening complication than can be triggered by prothrombotic conditions such as infection. Management of pump thrombosis presents as both a diagnostic and therapeutic challenge that is associated with a high morbidity and mortality. We report a case of pump thrombosis in a patient with a HeartMate II (Abbott Laboratories, Chicago, IL) and coronavirus (COVID-19) infection that was treated successfully with an intravenous thrombolytic, tissue plasminogen activator

Separation of breast cancer and organ microenvironment transcriptomes in metastases

Abstract Background The seed and soil hypothesis was proposed over a century ago to describe why cancer cells (seeds) grow in certain organs (soil). Since then, the genetic properties that define the cancer cells have been heavily investigated; however, genomic mediators within the organ microenvironment that mediate successful metastatic growth are less understood. These studies sought to identify cancer- and organ-specific genomic programs that mediate metastasis. Methods In these studies, a set of 14 human breast cancer patient-derived xenograft (PDX) metastasis models was developed and then tested for metastatic tropism with two approaches: spontaneous metastases from mammary tumors and intravenous injection of PDX cells. The transcriptomes of the cancer cells when growing as tumors or metastases were separated from the transcriptomes of the microenvironment via species-specific separation of the genomes. Drug treatment of PDX spheroids was performed to determine if genes activated in metastases may identify targetable mediators of viability. Results The experimental approaches that generated metastases in PDX models were identified. RNA sequencing of 134 tumors, metastases, and normal non-metastatic organs identified cancer- and organ-specific genomic properties that mediated metastasis. A common genomic response of the liver microenvironment was found to occur in reaction to the invading PDX cells. Genes within the cancer cells were found to be either transiently regulated by the microenvironment or permanently altered due to clonal selection of metastatic sublines. Gene Set Enrichment Analyses identified more than 400 gene signatures that were commonly activated in metastases across basal-like PDXs. A Src signaling signature was found to be extensively upregulated in metastases, and Src inhibitors were found to be cytotoxic to PDX spheroids. Conclusions These studies identified that during the growth of breast cancer metastases, there were genomic changes that occurred within both the cancer cells and the organ microenvironment. We hypothesize that pathways upregulated in metastases are mediators of viability and that simultaneously targeting changes within different cancer cell pathways and/or different tissue compartments may be needed for inhibition of disease progression