172 research outputs found
Bone Regeneration in Artificial Jaw Cleft by Use of Carbonated Hydroxyapatite Particles and Mesenchymal Stem Cells Derived from Iliac Bone
Objectives of the Study. Cleft lip and palate (CLP) is a prevalent congenital anomaly in the orofacial region. Autogenous iliac bone grafting has been frequently employed for the closure of bone defects at the jaw cleft site. Since the related surgical procedures are quite invasive for patients, it is of great importance to develop a new less invasive technique. The aim of this study was to examine bone regeneration with mesenchyme stem cells (MSCs) for the treatment of bone defect in artificially created jaw cleft in dogs. Materials and Methods. A bone defect was prepared bilaterally in the upper incisor regions of beagle dogs. MSCs derived from iliac bone marrow were cultured and transplanted with carbonated hydroxyapatite (CAP) particles into the bone defect area. The bone regeneration was evaluated by standardized occlusal X-ray examination and histological observation. Results. Six months after the transplantation, perfect closure of the jaw cleft was achieved on the experimental side. The X-ray and histological examination revealed that the regenerated bone on the experimental side was almost equivalent to the original bone adjoining the jaw cleft. Conclusion. It was suggested that the application of MSCs with CAP particles can become a new treatment modality for bone regeneration for CLP patients
Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas Giants
We compare the planet-to-star mass-ratio distribution measured by
gravitational microlensing to core accretion theory predictions from population
synthesis models. The core accretion theory's runaway gas accretion process
predicts a dearth of intermediate-mass giant planets that is not seen in the
microlensing results. In particular, the models predict fewer
planets at mass ratios of than inferred
from microlensing observations. This tension implies that gas giant formation
may involve processes that have hitherto been overlooked by existing core
accretion models or that the planet-forming environment varies considerably as
a function of host-star mass. Variation from the usual assumptions for the
protoplanetary disk viscosity and thickness could reduce this discrepancy, but
such changes might conflict with microlensing results at larger or smaller mass
ratios, or with other observations. The resolution of this discrepancy may have
important implications for planetary habitability because it has been suggested
that the runaway gas accretion process may have triggered the delivery of water
to our inner solar system. So, an understanding of giant planet formation may
help us to determine the occurrence rate of habitable planets.Comment: 12 pages, 2 figures, 1 table, accepted for publication in ApJ
RNA Modification in Inflammatory Bowel Diseases
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder characterized by damage to the intestinal mucosa, which is caused by a combination of factors. These include genetic and epigenetic alterations, environmental influence, microorganism interactions, and immune conditions. Some populations with IBD show a cancer-prone phenotype. Recent studies have provided insight into the involvement of RNA modifications in the specific pathogenesis of IBD through regulation of RNA biology in epithelial and immune cells. Studies of several RNA modification-targeting reagents have shown preferable outcomes in patients with colitis. Here, we note a new awareness of RNA modification in the targeting of IBD and related diseases, which will contribute to early diagnosis, disease monitoring, and possible control by innovative therapeutic approaches
Pulmonary Artery Leiomyosarcoma Diagnosed without Delay
A 63-year-old female presented with abnormal lung shadows but had, apart from this, few symptoms. Computed tomography (CT) revealed multiple nodules and blockage of the pulmonary artery. She was immediately diagnosed with pulmonary artery sarcoma based on a careful differential diagnosis and underwent surgery. Her tumor was pathologically diagnosed as leiomyosarcoma (i.e. intimal sarcoma). Pulmonary artery sarcoma can be easily confounded with thromboembolism in a clinical setting and some cases are diagnosed post mortem only. In our case, clinical prediction scores (Wells score, Geneva score, and revised Geneva score) for the pulmonary embolism showed low probability. Moreover, chest CT showed uncommon findings for pulmonary thromboembolism, as the nodules were too big for thrombi. Because surgical resection can provide the only hope of long-term survival in cases of pulmonary artery sarcoma, clinicians should consider this possibility in the differential diagnosis of pulmonary embolism. Clinical prediction scores and CT findings might help to reach the correct diagnosis of pulmonary artery sarcoma
Sleep-EEG-based parameters for discriminating fatigue and sleepiness
Sleep quality can be evaluated from the viewpoint of recovery from fatigue and sleepiness; however, it is difficult to investigate sleep quality while distinguishing between the two. The aim of this study is to find biomarkers that can discriminate between daytime fatigue and sleepiness and to assess sleep quality in consideration thereof. We collected answers to questionnaires regarding daytime fatigue and sleepiness, as well as EEG data measured during sleep, from 754 city government employees in a rural area of Japan. The respondents were categorized into four groups in accordance with the severity of fatigue and sleepiness as assessed by the questionnaires: fatigued and sleepy (FS), fatigued, non-sleepy (FO), non-fatigued and sleepy (SO), and non-fatigued and non-sleepy (neither fatigued nor sleepy; NE) groups. EEG data of medial frontal electrodes were obtained with a one-channel portable electroencephalograph, and various sleep parameters such as powers or sleep durations in each stage were compared among the four groups. Statistical tests confirmed significant differences in some derived sleep parameters among the four groups. The Theta Delta power may be a biomarker that can discriminate between fatigue and sleepiness. In addition, the Delta and Theta powers may be associated with sleep quality in terms of recovery from sleepiness and fatigue, respectively. Moreover, high frequency or long duration of mid-arousals may contribute to recovery from fatigue. The results showed that fatigue and sleepiness have different effects on sleep, and multiple sleep parameters derived from EEG are associated with sleep quality
Work Habit-Related Sleep Debt; Insights From Factor Identification Analysis of Actigraphy Data.
The present study investigates the factors of "Weekday sleep debt (WSD)" by comparing activity datacollected from persons with and without WSD. Since it has been reported that the amount of sleep debt aswell the difference between the social clock and the biological clock is associated with WSD, specifying thefactors of WSD other than chronotype may contribute to sleep debt prevention. We recruited 324 healthy male employees working at the same company and collected their 1-week wrist actigraphy data and answers to questionnaires. Because 106 participants were excluded due to measurement failure of the actigraphy data, the remaining 218 participants were included in the analysis. All participants were classified into WSD or non-WSD groups, in which persons had WDS if the difference between their weekend sleep duration and the mean weekday sleep duration was more than 120 min. We evaluated multiple measurements derived from the collected actigraphy data and trained a classifier that predicts thepresence of WSD using these measurements. A support vector machine (SVM) was adopted as the classifier. In addition, to evaluate the contribution of each indicator to WSD, permutation feature importance was calculated based on the trained classifier. Our analysis results showed significant importance of the following three out of the tested 32 factors: (1) WSD was significantly related to personswith evening tendency. (2) Daily activity rhythms and sleep were less stable in the WSD group than in thenon-WSD group. (3) A specific day of the week had the highest importance in our data, suggesting thatwork habit contributes to WSD. These findings indicate some WSD factors: evening chronotype, instability of the daily activity rhythm, and differences in work habits on the specific day of the week. Thus, it is necessary to evaluate the rhythms of diurnal activities as well as sleep conditions to identify the WSDfactors. In particular, the diurnal activity rhythm influences WSD. It is suggested that proper management of activity rhythm may contribute to the prevention of sleep debt
Free-Floating planet Mass Function from MOA-II 9-year survey towards the Galactic Bulge
We present the first measurement of the mass function of free-floating
planets (FFP) or very wide orbit planets down to an Earth mass, from the MOA-II
microlensing survey in 2006-2014. Six events are likely to be due to planets
with Einstein radius crossing times, days, and the shortest has
days and an angular Einstein radius of as. We measure the detection efficiency depending on both
and with image level simulations for the first
time. These short events are well modeled by a power-law mass function,
dexstar with for . This implies a total of FFP or very wide orbit
planets of mass per star, with a total mass of
per star. The number of FFPs is
times the number of planets in wide orbits (beyond the snow line), while the
total masses are of the same order. This suggests that the FFPs have been
ejected from bound planetary systems that may have had an initial mass function
with a power-law index of , which would imply a total mass of
star. This model predicts that Roman Space
Telescope will detect FFPs with masses down to that of
Mars (including with ). The
Sumi(2011) large Jupiter-mass FFP population is excluded.Comment: 17 pages, 7 figures, accepted for publication in A
A Planetary Microlensing Event with an Unusually Red Source Star: MOA-2011-BLG-291
We present the analysis of planetary microlensing event MOA-2011-BLG-291,
which has a mass ratio of and a source star that
is redder (or brighter) than the bulge main sequence. This event is located at
a low Galactic latitude in the survey area that is currently planned for NASA's
WFIRST exoplanet microlensing survey. This unusual color for a microlensed
source star implies that we cannot assume that the source star is in the
Galactic bulge. The favored interpretation is that the source star is a lower
main sequence star at a distance of kpc in the Galactic disk.
However, the source could also be a turn-off star on the far side of the bulge
or a sub-giant in the far side of the Galactic disk if it experiences
significantly more reddening than the bulge red clump stars. However, these
possibilities have only a small effect on our mass estimates for the host star
and planet. We find host star and planet masses of and from a Bayesian
analysis with a standard Galactic model under the assumption that the planet
hosting probability does not depend on the host mass or distance. However, if
we attempt to measure the host and planet masses with host star brightness
measurements from high angular resolution follow-up imaging, the implied masses
will be sensitive to the host star distance. The WFIRST exoplanet microlensing
survey is expected to use this method to determine the masses for many of the
planetary systems that it discovers, so this issue has important design
implications for the WFIRST exoplanet microlensing survey
Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii
Short-timescale microlensing events are likely to be produced by substellar brown dwarfs (BDs), but it is difficult to securely identify BD lenses based on only event timescales t_E because short-timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD-lens events found from the search for lensing events not only with short timescales (t_E ≲ 6 days) but also with very small angular Einstein radii (θ_E ≲ 0.05 mas) among the events that have been found in the 2016–2019 observing seasons. These events include MOA-2017-BLG-147, MOA-2017-BLG-241, and MOA-2019-BLG-256, in which the first two events are produced by single lenses and the last event is produced by a binary lens. From the Monte Carlo simulations of Galactic events conducted with the combined t_E and θ_E constraint, it is estimated that the lens masses of the individual events are
0.051^(+0.100)_(−0.027) M⊙, 0.044^(+0.090)_(−0.023) M⊙, and 0.046^(+0.067)_(−0.023) M⊙/0.038^(+0.056)_(−0.019) M⊙ and the probability of the lens mass smaller than the lower limit of stars is ~80% for all events. We point out that routine lens mass measurements of short-timescale lensing events require survey-mode space-based observations
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