516 research outputs found
Case Report: Intrapulmonary Arteriovenous Anastomoses in COVID-19-Related Pulmonary Vascular Changes: A New Player in the Arena?
Up to now, COVID-19-related vascular changes were mainly described as thrombo-embolic events. A handful of researchers reported another type of vascular abnormality referred to as "vascular thickening" or "vascular enlargement," without specifying whether the dilated vessels are arteries or veins nor providing a physiopathological hypothesis. Our observations indicate that the vascular dilatation occurs in the venous compartment, and underlying mechanisms might include increased blood flow due to inflammation and the activation of arteriovenous anastomoses
Solvability for a nonlinear coupled system of Kirchhoff type for the beam equations with nonlocal boundary conditions
In this paper, we investigate a mathematical model for a nonlinear coupled system of Kirchhoff type of beam equations with nonlocal boundary conditions. We establish existence, regularity and uniqueness of strong solutions. Furthermore, we prove the uniform rate of exponential decay. The uniform rate of polynomial decay is considered
Impact of COVID-19 pneumonia on pulmonary vascular volume.
Pulmonary manifestations of COVID-19 pneumonia are well known. However, COVID-19 is also associated with a range of vascular manifestations such as embolism, congestion, and perfusion changes. Regarding congestion, research from different groups has suggested arteriovenous anastomosis dysregulation as a contributing factor. In this study, we aim to better describe the changes in vascular volume in affected lung zones and to relate them to pathophysiological hypotheses.
We performed automatic vascular volume extraction in 10 chest CTs of patients, including 2 female and 8 male with a mean age of 63.5 ± 9.3 years, diagnosed with COVID-19 pneumonia. We compared the proportion of vascular volumes between manually segmented regions of lung parenchyma with and without signs of pneumonia.
The proportion of vascular volume was significantly higher in COVID (CVasc) compared to non-COVID (NCVasc) areas. We found a mean difference (DVasc) of 5% and a mean ratio (RVasc) of 3.7 between the two compartments (p < 0.01).
Vascular volume in COVID-19 affected lung parenchyma is augmented relative to normal lung parenchyma, indicating venous congestion and supporting the hypothesis of pre-existing intra-pulmonary arteriovenous shunts
Manganese Defective Clustering: Influence on the Spectroscopic Features of Ceria-Based Nanomaterials
The influence of manganese modification on the spectroscopic features of manganese-doped CeO2 systems synthesized by the microwave-assisted hydrothermal route and their correlation with the presence of O defective structures were verified, focusing on their interaction with poisonous atmospheres. Raman and electron paramagnetic resonance studies confirmed the presence of defective clusters formed by dipoles and/or quadrupoles. The number of paramagnetic species was found to be inversely proportional to the doping concentration, resulting in an increase in the Mn2+ signal, likely due to the reduction of Mn3+ species after the interaction with CO. X-ray photoelectron spectroscopy data showed the pure system with 33% of its cerium species in the Ce3+ configuration, with an abrupt decrease to 19%, after the first modification with Mn, suggesting that 14% of the Ce3+ species are donating one electron to the Mn2+ ions, thus becoming nonparamagnetic Ce4+ species. On the contrary, 58% of the manganese species remain in the Mn2+ configuration with five unpaired electrons, corroborating the paramagnetic feature of the samples seen in the electron paramagnetic resonance study
RemixDrum: A smart musical instrument for music and visual art remix
The remix technique has been widely used in musical
\npractice, mainly due to the figure of Disc Jockeys (DJs), which
\ncombines several pre-existing sounds to produce completely new
\ncontent. However, this creation method also appears in other
\nforms of artistic expressions, such as architecture, photography,
\nfashion design, video games, etc. Recent technological advances
\nfavor the emergence of gadgets that help expand this practice,
\nsuch as Smart Musical Instruments (SMI), devices equipped
\nwith sensors, actuators, embedded intelligence, and wireless
\nconnectivity to allow new forms of musical expression. In view
\nof this scenario and the versatility of remix, this paper presents
\na prototype of an SMI, called RemixDrum, conceived not only
\nfor creating sounds through technological means but also to
\nallow the mixing of multimedia content, proposing a new context
\nof use for this type of interface and a new way to make art.
\nFinally, the prototype was evaluated quantitatively, measuring
\naverage latency, jitter and throughput, qualitatively, investigating
\nthe user experience and their interaction with the equipment,
\nand comparatively, through an analysis between our prototype
\nand related works, in order to analyze perceptible delays,
\nexpressiveness and other artistic factors
Vitamin E-analog Trolox prevents endoplasmic reticulum stress in frozen-thawed ovarian tissue of capuchin monkey (Sapajus apella)
Ovarian fragments were exposed to 0.5 M sucrose
and 1 M ethylene glycol (freezing solution; FS) with or
without selenium or Trolox. Histological and ultrastructural
analyses showed that the percentages of normal follicles in
control tissue and in tissue after exposure to FS+50 μM
Trolox were similar. Trolox prevented endoplasmic reticulum
(ER)-related vacuolization, which is commonly observed in
oocytes and stromal tissue after exposure to FS. From the evaluated stress markers, superoxide dismutase 1 (SOD1)
was up-regulated in ovarian tissue exposed to FS+10 ng/ml
selenium. Ovarian fragments were subsequently frozenthawed
in the presence of FS with or without 50 μM Trolox,
followed by in vitro culture (IVC). Antioxidant capacity in
ovarian fragments decreased after freeze-thawing in Troloxfree
FS compared with FS+50 μMTrolox. Although freezing
itself minimized the percentage of viable follicles in each solution, Trolox supplementation resulted in higher rates of
viable follicles (67 %), even after IVC (61 %). Furthermore,
stress markers SOD1 and ERp29 were up-regulated in ovarian
tissue frozen-thawed in Trolox-free medium. Relative mRNA
expression of growth factors markers was evaluated after
freeze-thawing followed by IVC. BMP4, BMP5, CTGF,
GDF9 and KL were down-regulated independently of the
presence of Trolox in FS but down-regulation was less pronounced
in the presence of Trolox. Thus, medium supplementation
with 50 μMTrolox prevents ER stress and, consequently,
protects ovarian tissue from ER-derived cytoplasmic
vacuolization. ERp29 but not ERp60, appears to be a key
marker linking stress caused by freezing-thawing and cell
vacuolization.http://link.springer.com/journal/441hb201
Influence of scrotal bipartition on spermatogenesis yield and sertoli cell efficiency in sheep
Abstract With the objective to assess the effect of scrotal bipartition on spermatogenesis in sheep, the testes were used from 12 crossbred rams of sheep farms in the municipality of Patos, Paraíba, Brazil, distributed into two groups: GI with six rams with scrotal bipartition, and GII with six rams without scrotal bipartition. The testicular biometry was measured and the testes were collected, fixed in Bouin and fragments were processed to obtain histological slides. The spermatogenesis yield and the Sertoli cell efficiency was estimated by counting the cells of the spermatogenetic line at stage one of the seminiferous epithelium cycle and the Sertoli cells. The results were submitted to analysis of variance with the ASSISTAT v.7.6 program and the mean values were compared by the Student-Newman-Keuls test (SNK) at 5% significance. The testicular biometric parameters did not show statistical difference (p>0.05) between the groups. The meiotic, spermatogenetic and Sertoli cell efficiency were higher in bipartitioned rams (p0.05) between GI and GII. The results indicated that there is superiority in the spermatogenetic parameters of bi-partitioned rams, suggesting that these sheep present, as reported in goats, indication of better reproductive indices
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