Optimum Functions for Radial Wires of Monopole Antennas with Arbitrary Elevation Angles

Monopole antennas on the earth usually use ground screen with simple radial wires to improve their radiation performance. The number of radials,N, is usually considered a constant in the screen. This paper studies the effect of changing N and considering it as a function of distance, ρ, from the monopole using a simple and yet a fast method. The function N(ρ) is optimized for different beam angles of an HF monopoleantenna. The theoretical functions are converted to practical functions to be formed using meandered lines. Practicable calculated results are validated bymethod of moments. Furthermore it is shown that for low angle radiation aconstant N(ρ) with optimized radius of the ground screen is the best choice. The results can be used for higher frequencies, i.e. VHF and UHF frequency bands as well

The Rules of Human T Cell Fate in vivo.

The processes governing lymphocyte fate (division, differentiation, and death), are typically assumed to be independent of cell age. This assumption has been challenged by a series of elegant studies which clearly show that, for murine cells in vitro, lymphocyte fate is age-dependent and that younger cells (i.e., cells which have recently divided) are less likely to divide or die. Here we investigate whether the same rules determine human T cell fate in vivo. We combined data from in vivo stable isotope labeling in healthy humans with stochastic, agent-based mathematical modeling. We show firstly that the choice of model paradigm has a large impact on parameter estimates obtained using stable isotope labeling i.e., different models fitted to the same data can yield very different estimates of T cell lifespan. Secondly, we found no evidence in humans in vivo to support the model in which younger T cells are less likely to divide or die. This age-dependent model never provided the best description of isotope labeling; this was true for naïve and memory, CD4+ and CD8+ T cells. Furthermore, this age-dependent model also failed to predict an independent data set in which the link between division and death was explored using Annexin V and deuterated glucose. In contrast, the age-independent model provided the best description of both naïve and memory T cell dynamics and was also able to predict the independent dataset

Three-dimensional graphene foam as a conductive scaffold for cardiac tissue engineering

Myocardial infarction is one of the major causes of mortality throughout the world. Cardiac scaffolds are tissue-engineered structures for the treatment of myocardial infarction and are employed for tissue support and cell delivery to the injured region. In this study, we fabricated nanostructured graphene foams as porous and biocompatible cardiac tissue-engineering scaffolds. Three-dimensional graphene foam and two-dimensional graphene were fabricated using chemical vapor deposition. We showed that the nickel etching had no effect on the structural appearance of the three-dimensional graphene foam. Toxicity of the prepared samples was evaluated on human umbilical vein endothelial cells at 48 h and 72 h and showed no toxic effects on the viability of the cells. Moreover, both samples supported the adhesion and growth of neonatal cardiomyocytes with three-dimensional graphene foam showing a more extensive effect on the expression of the cardiac genes involved in muscle contraction and relaxation (troponin-T) and gap junctions (Connexin 43). Hence, conductive three-dimensional graphene foam with its large surface area and specific surface properties could provide a promising platform for cardiac tissue engineering. © The Author(s) 2019

Selenium Supplementation and the Effects on Reproductive Outcomes, Biomarkers of Inflammation, and Oxidative Stress in Women with Polycystic Ovary Syndrome

Selenium supplementation could be effective on reproductive outcomes, biomarkers of inflammation, and oxidative stress among women with polycystic ovary syndrome (PCOS). The aim of the study was to determine the effects of selenium supplementation on reproductive outcomes, biomarkers of inflammation, and oxidative stress in PCOS patients. The present randomized double-blind, placebo-controlled trial was conducted on 64 women aged 18-40 years old with PCOS at the clinic affiliated to Ardabil University of Medical Sciences, Ardabil, Iran. The participants were randomly assigned to 2 groups receiving either 200 μg selenium daily (n=32) or placebo (n=32) for 8 weeks. Hormonal profiles, biomarkers of inflammation, and oxidative stress were measured and compared both before and after the treatment. After 8 weeks of intervention, pregnancy rate in the selenium group was higher than in the placebo group: 18.8 (6/32) vs. 3.1 (1/32), p=0.04. In addition, alopecia (40.6 vs. 9.4, p=0.004) and acne (46.9 vs. 12.5 , p=0.003) decreased following the consumption of selenium supplements compared with placebo. Additionally, patients who received selenium supplements had significantly decreased serum dehydroepiandrosterone (DHEA) levels (p=0.02), hirsutism (modified Ferriman-Gallwey scores) (p<0.001), serum high sensitivity C-reactive protein (hs-CRP) (p=0.02), and plasma malondialdehyde (MDA) levels (p=0.01) compared with placebo. We did not observe any significant effects of taking selenium supplements on other hormonal profiles, nitric oxide (NO), and other biomarkers of oxidative stress. Taken together, selenium supplementation for 8 weeks among PCOS women had beneficial effects on reproductive outcomes, DHEA, hs-CRP, and MDA levels. Supporting Information for this article is available online at http://www.thieme-connect.de/products. © Georg Thieme Verlag KG Stuttgart. New York

The role of vitamin D in the age of COVID-19: A systematic review and meta-analysis

Background: Evidence recommends that vitamin D might be a crucial supportive agent for the immune system, mainly in cytokine response regulation against COVID-19. Hence, we carried out a systematic review and meta-analysis in order to maximise the use of everything that exists about the role of vitamin D in the COVID-19. Methods: A systematic search was performed in PubMed, Scopus, Embase and Web of Science up to December 18, 2020. Studies focused on the role of vitamin D in confirmed COVID-19 patients were entered into the systematic review. Results: Twenty-three studies containing 11 901 participants entered into the meta-analysis. The meta-analysis indicated that 41 of COVID-19 patients were suffering from vitamin D deficiency (95 CI, 29-55), and in 42 of patients, levels of vitamin D were insufficient (95 CI, 24-63). The serum 25-hydroxyvitamin D concentration was 20.3 ng/mL among all COVID-19 patients (95 CI, 12.1-19.8). The odds of getting infected with SARS-CoV-2 are 3.3 times higher among individuals with vitamin D deficiency (95 CI, 2.5-4.3). The chance of developing severe COVID-19 is about five times higher in patients with vitamin D deficiency (OR: 5.1, 95 CI, 2.6-10.3). There is no significant association between vitamin D status and higher mortality rates (OR: 1.6, 95 CI, 0.5-4.4). Conclusion: This study found that most of the COVID-19 patients were suffering from vitamin D deficiency/insufficiency. Also, there is about three times higher chance of getting infected with SARS-CoV-2 among vitamin-D-deficient individuals and about five times higher probability of developing the severe disease in vitamin-D-deficient patients. Vitamin D deficiency showed no significant association with mortality rates in this population. © 2021 John Wiley & Sons Lt

Global mortality associated with 33 bacterial pathogens in 2019: a systematic analysis for the Global Burden of Disease Study 2019

Background Reducing the burden of death due to infection is an urgent global public health priority. Previous studies have estimated the number of deaths associated with drug-resistant infections and sepsis and found that infections remain a leading cause of death globally. Understanding the global burden of common bacterial pathogens (both susceptible and resistant to antimicrobials) is essential to identify the greatest threats to public health. To our knowledge, this is the first study to present global comprehensive estimates of deaths associated with 33 bacterial pathogens across 11 major infectious syndromes. Methods We estimated deaths associated with 33 bacterial genera or species across 11 infectious syndromes in 2019 using methods from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, in addition to a subset of the input data described in the Global Burden of Antimicrobial Resistance 2019 study. This study included 343 million individual records or isolates covering 11 361 study-location-years. We used three modelling steps to estimate the number of deaths associated with each pathogen: deaths in which infection had a role, the fraction of deaths due to infection that are attributable to a given infectious syndrome, and the fraction of deaths due to an infectious syndrome that are attributable to a given pathogen. Estimates were produced for all ages and for males and females across 204 countries and territories in 2019. 95% uncertainty intervals (UIs) were calculated for final estimates of deaths and infections associated with the 33 bacterial pathogens following standard GBD methods by taking the 2·5th and 97·5th percentiles across 1000 posterior draws for each quantity of interest. Findings From an estimated 13·7 million (95% UI 10·9–17·1) infection-related deaths in 2019, there were 7·7 million deaths (5·7–10·2) associated with the 33 bacterial pathogens (both resistant and susceptible to antimicrobials) across the 11 infectious syndromes estimated in this study. We estimated deaths associated with the 33 bacterial pathogens to comprise 13·6% (10·2–18·1) of all global deaths and 56·2% (52·1–60·1) of all sepsis-related deaths in 2019. Five leading pathogens—Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, and Pseudomonas aeruginosa—were responsible for 54·9% (52·9–56·9) of deaths among the investigated bacteria. The deadliest infectious syndromes and pathogens varied by location and age. The age-standardised mortality rate associated with these bacterial pathogens was highest in the sub-Saharan Africa super-region, with 230 deaths (185–285) per 100 000 population, and lowest in the high-income super-region, with 52·2 deaths (37·4–71·5) per 100 000 population. S aureus was the leading bacterial cause of death in 135 countries and was also associated with the most deaths in individuals older than 15 years, globally. Among children younger than 5 years, S pneumoniae was the pathogen associated with the most deaths. In 2019, more than 6 million deaths occurred as a result of three bacterial infectious syndromes, with lower respiratory infections and bloodstream infections each causing more than 2 million deaths and peritoneal and intra-abdominal infections causing more than 1 million deaths. Interpretation The 33 bacterial pathogens that we investigated in this study are a substantial source of health loss globally, with considerable variation in their distribution across infectious syndromes and locations. Compared with GBD Level 3 underlying causes of death, deaths associated with these bacteria would rank as the second leading cause of death globally in 2019; hence, they should be considered an urgent priority for intervention within the global health community. Strategies to address the burden of bacterial infections include infection prevention, optimised use of antibiotics, improved capacity for microbiological analysis, vaccine development, and improved and more pervasive use of available vaccines. These estimates can be used to help set priorities for vaccine need, demand, and development