118 research outputs found
Discovery of the shell structure via break radii in the outer halo of the Milky Way
Based on the \textit{Gaia} DR3 RR Lyrae catalog, we use two methods to fit
the density profiles with an improved broken power law, and find that there are
two break radii coinciding with the two apocenter pile-ups of high-eccentricity
Gaia-Sausage-Enceladus (GSE) merger. Also, there is a break caused by the
Sagittarius (Sgr) stream. Combining the positions of all breaks, we briefly
analyze the metallicity and its dispersion as a function of as well as its
distribution in cylindrical coordinates. For the clean sample, the
ellipsoid axial ratio in 36\,{\rm
kpc}\,\textless\,r\,\textless\,96\,{\rm kpc} becomes much smaller than that of
the inner halo (r\,\textless\,36\,{\rm kpc}), while the major axis has a
large uncertainty in the region of and the one in the region
of is obviously different from that dominated by the
Hercules-Aquila Cloud (HAC) and the Virgo Overdensity (VOD) in the inner halo,
which indicates that there is an over-density structure distributed at low
zenithal angles. Finally, we found that the over-density structure in the outer
halo (r\,\textgreater\,50\,{\rm kpc}) is shell-shaped and relatively
metal-rich compared to the outer background halo. We conclude that the shells
could be the apocenter pile-ups of the high-eccentricity GSE merger, which is
supported by previous numerical simulations.Comment: 16 pages, 14 Figures, accepted for publication in MNRA
The relationship between future self-continuity and intention to use Internet wealth management: The mediating role of tolerance of uncertainty and trait anxiety
This study aimed to analyze the mediating effect of tolerance of uncertainty (TU) and trait anxiety (TA) on future self-continuity (FSC) and intention to use Internet wealth management (IUIWM) systems. A questionnaire survey was distributed online and a total of 388 participants completed questionnaire, The questionnaire included the following scales: Chinese version of the FSC, Intention to Use the Internet Wealth Management, TU, and TA. Pearson correlation was used to investigate the correlation coefficient between variables while the sequential regression method was used to analyze relationship between variables. To analyze the collected data, the SPSS 26.0 was used. A two-step procedure was applied to analyze the mediation effect. Confirmatory factor analysis (CFA) was conducted to test the measurement model. Afterward, the Maximum Likelihood method was used for path analysis, and the Bias-corrected Bootstrap method was used to investigate determine the estimated value and confidence interval of the mediating effect
Self-organized Voids Revisited: Experimental Verification of the Formation Mechanism*
In this paper, several experiments were conducted to further clarify the
formation mechanism of self organized void array induced by a single laser
beam, including energy-related experiments, refractive-index-contrast-related
experiments, depth-related experiments and effective-numerical-aperture
experiment. These experiments indicate that the interface spherical aberration
is indeed responsible for the formation of void arrays
In ovo serial skeletal muscle diffusion tractography of the developing chick embryo using DTI: feasibility and correlation with histology
Abstract
Background
Magnetic resonance imaging is a noninvasive method of evaluating embryonic development. Diffusion tensor imaging (DTI), based on the directional diffusivity of water molecules, is an established method of evaluating tissue structure. Yet embryonic motion degrades the in vivo acquisition of long-duration DTI. We used a dual-cooling technique to avoid motion artifact and aimed to investigate whether DTI can be used to monitor chick embryonic skeletal muscle development in ovo, and to investigate the correlation between quantitative DTI parameters fractional anisotropy (FA) and fiber length and quantitative histologic parameters fiber area percentage (FiberArea%) and limb length.
Results
From 84 normally developing chick embryos, 5 were randomly chosen each day from incubation days 5 to 18 and scanned using 3.0 Tesla magnetic resonance imaging. A dual-cooling technique is used before and during imaging. Eggs were cracked for making histological specimen after imaging. 3 eggs were serially imaged from days 5 to 18. We show that skeletal muscle fibers can be tracked in hind limb in DTI beginning with incubation day 8. Our data shows a good positive correlation between quantitative DTI and histologic parameters (FA vs FiberArea%: r= 0.943, p\u3c0.0001; Fiber_length vs Limb_length: r=0.974, p\u3c0.0001). The result of tracked fibers in DTI during incubation corresponds to the development of chick embryonic skeletal muscle as reported in the literature.
Conclusion
Diffusion tensor imaging can provide a noninvasive means of evaluating skeletal muscle development in ovo
Association of Interleukin-2 Gene Polymorphism with Henoch-schönlein Purpura Nephritis
Henoch-Schönlein purpura nephritis (HSPN) is a common vasculitis that mostly affects children, and previous studies have indicated that genetic factors may influence disease susceptibility. The aim of this study was to evaluate a possible association of three interleukin-2 (IL-2) gene polymorphisms (rs3136534, rs2069776, and rs2069762) with HSPN in the Chinese population.
A total of 81 patients with HSPN and 200 healthy children were enrolled. The distribution of genotypes, allelic frequencies, and haplotype frequencies among the three IL-2 polymorphisms were analyzed using the Sequenom MassARRAY system by means of matrix-assisted laser desorption ionization-time of flight mass spectrometry method.
Compared to the healthy controls, genotyping analysis demonstrated rs3136534 was associated with a decreased HSPN risk in the dominant inheritance model (G/T+T/T vs. G/G; OR, 0.54; 95% CI, 0.31–0.93). However, the frequency of the T allele and haplotypes of rs3136534 showed no statistical significance. For the frequency of genotype, allele, and haplotype of the rs2069776 and rs20697622 polymorphisms, no significant differences were observed between HSPN patients and controls.
Our results suggest that the rs3136534 polymorphism of the IL-2 gene is associated with susceptibility to HSPN in Chinese children.
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Does Serum Vitamin D Level Affect COVID-19 Infection and Its Severity?-A Case-Control Study
Background: As effective medication to treat COVID-19 is currently unavailable, preventive remedies may be particularly important. Objective: To examine the relationship between serum 25-hydroxy vitamin D (25(OH)D) level and COVID-19 infection, its severity, and its clinical case characteristics. Methods: This case-control study compared serum 25(OH)D levels and rates of vitamin D deficiency (VDD) between 80 healthy controls and 62 patients diagnosed with COVID-19 and admitted to Guangxi People’s Hospital, China, 2/16/2020–3/16/2020. Cases were categorized into asymptomatic, mild/moderate, and severe/critical disease. Logistic regression analysis was conducted to examine the associations between 25(OH)D level, or VDD, and case status/severity of COVID-19 while controlling for demographics and comorbidities. A threshold level of vitamin D for conveying COVID-19 risk was estimated. Results: Severe/critical COVID-19 cases were significantly older and had higher percentages of comorbidity (renal failure) compared to mild cases. The serum 25(OH)D concentration in COVID-19 patient was much lower than that in healthy control. And 25(OH)D level was the lowest in severe/ critical cases, compared with mild cases. In further, significantly higher rates of VDD were found in COVID-19 cases (41.9%) compared to healthy controls (11.1%). And VDD was the greatest in severe/critical cases (80%), compared with mild cases (36%). These statistically significant associations remained even after controlling for demographics and comorbidities. A potential threshold of 25(OH)D (41.19nmol/L) to protect against COVID-19 was identified. Conclusion: Elderly and people with comorbidities were susceptible to severe COVID-19 infection. VDD was a risk factor for COVID-19, especially for severe/critical cases. While further confirmation is needed, vitamin D supplementation may have prevention or treatment potential for COVID- 19 disease
Effect of FTY720 on Some Physiological Indexes of Non-Obese Diabetic (NOD) Mice
The studies were performed to investigate the physiological characteristics of non-obese diabetic (NOD) mice treated with FTY720. At the age of 12 weeks, each mouse was fed with FTY720 or physiological saline once a day for 10 weeks running, and their blood glucose, weight, anti-GAD antibody and organ indexes were determined. No mouse in group FTY720 (NOD mice treated with FTY720) showed diabetic symptoms. The average content of serum anti-GAD antibody in group FTY720 decreased 48.75% (P < 0.01). It was concluded that the spleen, kidney and liver of NOD mice treated with FTY720 shriveled significantly in the progression of diabetes (P < 0.01 or P < 0.05). The body weight of group FTY720 mice was slightly lower than that of the model control (MC) group and these two groups both had less body weight than the normal control (NC) group (P < 0.01). The result of tests of anti-GAD antibody suggested that FTY720 treatment could suppress the anti-GAD response
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