740 research outputs found
Study of the island morphology at the early stages of Fe/Mo(110) MBE growth
We present theoretical study of morphology of Fe islands grown at Mo(110)
surface in sub-monolayer MBE mode. We utilize atomistic SOS model with bond
counting, and interactions of Fe adatom up to third nearest neighbors. We
performed KMC simulations for different values of adatom interactions and
varying temperatures. We have found that, while for the low temperature islands
are fat fractals, for the temperature 500K islands have faceted rhombic-like
shape. For the higher temperature, islands acquire a rounded shape. In order to
evaluated qualitatively morphological changes, we measured averaged aspect
ration of islands. We calculated dependence of the average aspect ratio on the
temperature, and on the strength of interactions of an adatom with neighbors.Comment: 6 pages, 6 figures. Proceedings of 11-th Symposium on Surface
Physics, Prague 200
Enhanced low-energy -decay strength of Ni and its robustness within the shell model
Neutron-capture reactions on very neutron-rich nuclei are essential for
heavy-element nucleosynthesis through the rapid neutron-capture process, now
shown to take place in neutron-star merger events. For these exotic nuclei,
radiative neutron capture is extremely sensitive to their -emission
probability at very low energies. In this work, we present
measurements of the -decay strength of Ni over the wide range
MeV. A significant enhancement is found in the
-decay strength for transitions with MeV. At present,
this is the most neutron-rich nucleus displaying this feature, proving that
this phenomenon is not restricted to stable nuclei. We have performed
-strength calculations within the quasiparticle time-blocking
approximation, which describe our data above MeV very well.
Moreover, large-scale shell-model calculations indicate an nature of the
low-energy strength. This turns out to be remarkably robust with
respect to the choice of interaction, truncation and model space, and we
predict its presence in the whole isotopic chain, in particular the
neutron-rich .Comment: 9 pages, 9 figure
On-Orbit Measurement of Next Generation Space Solar Cell Technology on the International Space Station
Measurement is essential for the evaluation of new photovoltaic (PV) technology for space solar cells. NASA Glenn Research Center (GRC) is in the process of measuring several solar cells in a supplemental experiment on NASA Goddard Space Flight Center's (GSFC) Robotic Refueling Mission's (RRM) Task Board 4 (TB4). Four industry and government partners have provided advanced PV devices for measurement and orbital environment testing. The experiment will be on-orbit for approximately 18 months. It is completely self-contained and will provide its own power and internal data storage. Several new cell technologies including four- junction (4J) Inverted Metamorphic Multijunction (IMM) cells will be evaluated and the results compared to ground-based measurements
New coronavirus disease 2019 (COVID-19): Is there an impact on male reproductive health
The male reproductive health depends on several factors that can be divided into two main groups: the first group, genetic or hereditary (in particular, Klinefelter syndrome, etc.), the second acquired factors that depend on the person's lifestyle (bad habits, diet), stress, infectious diseases of the genitourinary system, etc. The presence of infectious and inflammatory diseases of the male reproductive system leads to impaired reproductive and endocrine function, significantly reducing the reproductive potential. In the last three years of our time around the world, including Russia, the number of people who have become ill with a new viral infection (COVID-19) caused by the new coronavirus (SARS-CoV-2), which causes dysfunction and has a negative effect on many organs and organs, body systems.The overview of recent publications is devoted to the study of the effect of SARS-CoV-2 on the reproductive health of men. The search was performed using the Medline, PubMed, and EMBASE databases
Pathological findings in semen analysis from COVID-19 survivors and the impact of various SARS-COV-2 vaccines on spermatogenesis
Male reproductive health depends on many factors, including whether infectious diseases occur in the reproductive system. Such changes may be reflected in the semen analysis. In the past three years, the number of individuals who fell ill with COVID-19 caused by SARS-CoV-2 has been growing worldwide, including in Russia. This infection causes dysfunction and a negative effect on many organs and systems, including reproductive organs, which is reflected in abnormal semen parameters. Despite the high efficacy and small number of side effects found in clinical trials, only 56% of the population in the US and 49% in the Russian Federation reported wanting the vaccine. One of the reasons for distrust of vaccines is the potential negative impact on fertility. A literature review is devoted to the study of the effect of SARS-CoV-2 and vaccination on male reproductive health. The search was carried out using Medline, PubMed, and EMBASE databases
Extended Thromboprophylaxis with Betrixaban in Acutely Ill Medical Patients
Background
Patients with acute medical illnesses are at prolonged risk for venous thrombosis. However, the appropriate duration of thromboprophylaxis remains unknown.
Methods
Patients who were hospitalized for acute medical illnesses were randomly assigned to receive subcutaneous enoxaparin (at a dose of 40 mg once daily) for 10±4 days plus oral betrixaban placebo for 35 to 42 days or subcutaneous enoxaparin placebo for 10±4 days plus oral betrixaban (at a dose of 80 mg once daily) for 35 to 42 days. We performed sequential analyses in three prespecified, progressively inclusive cohorts: patients with an elevated d-dimer level (cohort 1), patients with an elevated d-dimer level or an age of at least 75 years (cohort 2), and all the enrolled patients (overall population cohort). The statistical analysis plan specified that if the between-group difference in any analysis in this sequence was not significant, the other analyses would be considered exploratory. The primary efficacy outcome was a composite of asymptomatic proximal deep-vein thrombosis and symptomatic venous thromboembolism. The principal safety outcome was major bleeding.
Results
A total of 7513 patients underwent randomization. In cohort 1, the primary efficacy outcome occurred in 6.9% of patients receiving betrixaban and 8.5% receiving enoxaparin (relative risk in the betrixaban group, 0.81; 95% confidence interval [CI], 0.65 to 1.00; P=0.054). The rates were 5.6% and 7.1%, respectively (relative risk, 0.80; 95% CI, 0.66 to 0.98; P=0.03) in cohort 2 and 5.3% and 7.0% (relative risk, 0.76; 95% CI, 0.63 to 0.92; P=0.006) in the overall population. (The last two analyses were considered to be exploratory owing to the result in cohort 1.) In the overall population, major bleeding occurred in 0.7% of the betrixaban group and 0.6% of the enoxaparin group (relative risk, 1.19; 95% CI, 0.67 to 2.12; P=0.55).
Conclusions
Among acutely ill medical patients with an elevated d-dimer level, there was no significant difference between extended-duration betrixaban and a standard regimen of enoxaparin in the prespecified primary efficacy outcome. However, prespecified exploratory analyses provided evidence suggesting a benefit for betrixaban in the two larger cohorts. (Funded by Portola Pharmaceuticals; APEX ClinicalTrials.gov number, NCT01583218. opens in new tab.
Morphological changes in testicles of patients with idiopathic infertility after novel coronavirus infection (COVID-19)
Introduction. SARS-CoV-2 causes several negative processes in the body and complicates the course of chronic somatic diseases, causing dysfunction and having a negative effect on many organs and systems of the body, including organs of the reproductive system.Objective. To study morphological changes in testicles of patients who have undergone a new coronavirus infection.Materials and methods. Objects of morphological research were testicular tissues obtained by intraoperative biopsy under intravenous anesthesia served. Material sampling was carried out in 12 patients aged 25–29 years with idiopathic infertility who underwent COVID-19. Patients showed ultrasound signs of fibrosis in the testicles, which were absent before infection with SARS-CoV-2. The biopsy was performed 12 months after COVID-19.Results. In all observations, changes were observed that are characteristic of the inflammatory process, nonbacterial autoimmune genesis. Histio-lymphocytic infiltration of testicular tissue with destruction of single tubules and parenchyma atrophy, combined with varying degrees of sclerosis, was verified.Conclusion. In testicular biopsy specimens from patients who have undergone COVID-19, an autoimmune inflammatory process is recorded, manifested by lymphocytic infiltration of testicular tissue, which was combined with varying degrees of sclerosis
Recent growth coherence in long-term oak (Quercus spp.) ring width chronologies in the Czech Republic
At last, a Pennsylvanian stem-stonefly (Plecoptera) discovered
<p>Abstract</p> <p>Background</p> <p>Stem-relatives of many winged insect orders have been identified among Pennsylvanian fossils (Carboniferous Period). Owing to their presumed 'basal' position in insect phylogeny, stoneflies were expected to occur at this period. However, no relative has ever been designated convincingly.</p> <p>Results</p> <p>In this paper, we report specimens belonging to a new fossil insect species collected from the Tupo Formation (Pennsylvanian; China). The wing venation of <it>Gulou carpenteri </it><b>gen. et sp. nov</b>. exhibits character states diagnostic of the order Plecoptera, but lack character states shared by unequivocal representatives of the order. Derived from this identification, the delimitation of the fossil species is ascertained based on comparison of several extant stonefly species. This comparative analysis allowed a trait present in <it>G. carpenteri </it><b>gen. et sp. nov</b>., but rarely occurring in extant species, to be documented and highlighted as atavistic. Affinities of taxa formerly proposed as putative stem-stoneflies are reconsidered in the light of the new discovery.</p> <p>Conclusions</p> <p><it>Gulou carpenteri </it><b>gen. et sp. nov</b>. is considered the only genuine Plecoptera reported from the Pennsylvanian. Continuing efforts on the systematics of Pennsylvanian winged insects indicate a fauna more diverse than previously appreciated. It suggests that insects already had a long, yet undocumented, history by this time.</p
Nonpharmacologic Therapies in Patients With Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review With Meta-Analysis
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