583 research outputs found
The Light and Period Variations of the Eclipsing Binary BX Draconis
New CCD photometric observations of BX Dra were obtained for 26 nights from
2009 April to 2010 June. The long-term photometric behaviors of the system are
presented from detailed studies of the period and light variations, based on
the historical data and our new observations. All available light curves
display total eclipses at secondary minima and inverse O'Connell effects with
Max I fainter than Max II, which are satisfactorily modeled by adding the
slightly time-varying hot spot on the primary star. A total of 87 times of
minimum light spanning over about 74 yrs, including our 22 timing measurements,
were used for ephemeris computations. Detailed analysis of the O-C diagram
showed that the orbital period has changed in combinations with an upward
parabola and a sinusoidal variation. The continuous period increase with a rate
of +5.65 \times 10^-7 d yr^-1 is consistent with that calculated from the
Wilson-Devinney synthesis code. It can be interpreted as a mass transfer from
the secondary to the primary star at a rate of 2.74 \times 10^-7 M\odot yr^-1,
which is one of the largest rates for contact systems. The most likely
explanation of the sinusoidal variation with a period of 30.2 yrs and a
semi-amplitude of 0.0062 d is a light-traveltime effect due to the existence of
a circumbinary object. We suggest that BX Dra is probably a triple system,
consisting of a primary star with a spectral type of F0, its secondary
component of spectral type F1-2, and an unseen circumbinary object with a
minimum mass of M3 = 0.23 M\odot.Comment: 24 pages, including 5 figures and 9 tables, accepted for publication
in PAS
Electrical Investigation of the Oblique Hanle Effect in Ferromagnet/Oxide/Semiconductor Contacts
We have investigated the electrical Hanle effect with magnetic fields applied
at an oblique angle ({\theta}) to the spin direction (the oblique Hanle effect,
OHE) in CoFe/MgO/semiconductor (SC) contacts by employing a three-terminal
measurement scheme. The electrical oblique Hanle signals obtained in
CoFe/MgO/Si and CoFe/MgO/Ge contacts show clearly different line shapes
depending on the spin lifetime of the host SC. Notably, at moderate magnetic
fields, the asymptotic values of the oblique Hanle signals (in both contacts)
are consistently reduced by a factor of cos^2({\theta}) irrespective of the
bias current and temperature. These results are in good agreement with
predictions of the spin precession and relaxation model for the electrical
oblique Hanle effect. At high magnetic fields where the magnetization of CoFe
is significantly tilted from the film plane to the magnetic field direction, we
find that the observed angular dependence of voltage signals in the CoFe/MgO/Si
and CoFe/MgO/Ge contacts are well explained by the OHE, considering the
misalignment angle between the external magnetic field and the magnetization of
CoFe.Comment: 19 pages, 8 figure
Enzymatic hydrolysate from velvet antler suppresses adipogenesis in 3T3-L1 cells and attenuates obesity in high-fat diet-fed mice
The purpose of the current study was to investigate the potential anti-obesity activity of an enzymatic hydrolysate of velvet antler in inhibiting adipogenesis in 3T3-L1 cells and in high-fat diet (HFD)-fed obese mice. The enzy- matic hydrolysate was prepared using the commercial food grade protease, Protamex. The velvet antler Protamex hydrolysate (VAPH) indicated profound inhibitory effects on adipogenesis dose-dependently by decreasing the accumulation of triglycerides and down-regulating expression levels of adipogenesis-related proteins C/EBPα, SREBP-1, and PPARγ. In a mouse model of HFD-induced obesity, oral administration of VAPH (100 and 300 mg/kg for 13 weeks) significantly reduced the body weight gain that had resulted from the HFD. VAPH treat- ment also lowered the serum glucose and triglyceride levels, while increasing the HDL-C level. Furthermore, the treatment greatly reduced hepatic lipid droplet accumulation as well as the size of adipocytes. Current findings H has profound anti-obesity effects and could be an effective candidate for preventing obesity and obesity-related chronic diseases
A New SX Phe Star in the Globular Cluster M15
A new SX Phe star (labelled SXP1) found from CCD photometry is the first
to be discovered in the globular cluster M15. It is a blue straggler and is
located 102\arcsec.8 north and 285\arcsec.6 west of the center of M15
\citep{har96}. Mean magnitudes of SXP1 are = 18$\fm$671 and
= 18\fm445. The amplitude of variability of SXP1 is measured to be . From multiple-frequency analysis based on the Fourier
decomposition method, we detect two very closely separated pulsating
frequencies: the primary frequency at c/d for both - and
-bands, and the secondary frequency at c/d for the -band and
24.343 c/d for the -band. This star is the second among known SX Phe stars
found to pulsate with very closely separated frequencies ().
These frequencies may be explained by excitation of nonradial modes; however,
we have an incomplete understanding of this phenomenon in the case of SX Phe
stars with relatively high amplitudes. The metallicity-period and the
variability amplitude-period relations for SXP1 in M15 are found to be
consistent with those for SX Phe stars in other globular clusters.Comment: 15 pages with 6 figures, accepted by the Astronomical Journal
(scheduled May 2001
New-type of Multi-purpose Standard Radon Chamber in South Korea
Radon is an inert and a radioactive gas which is colorless, tasteless and odorless. As the radon decay proceeds, and if DNA damage continues beyond repair capacity of cells in the human body, it can cause severe health problems such as lung cancer in the long-term. There is a tendency that those countries where legal restriction on radon is strict, various studies related to radon are under way. In South Korea, radon has been regulated under recommendation level. Even though there are about 3 standard radon chambers in Korea, they have not been in an active use because of lack of demand. Also, most of them are specialized in calibration of radon detectors only. Recently, Korean government started giving some attention to radon issue and supporting radon research fields. Thus, this study was carried out to develop a new type of radon chamber for multi-purpose such as 1) radon emission rate from natural and artificial radon sources; 2) calibration of radon detectors; 3) evaluation of radon mitigation efficiency. Keywords: Radon, Radon Chamber, Indoor Air Quality, Chamber Desig
Anti-inflammatory effects of enzymatic hydrolysates of velvet antler in RAW 264.7 cells in vitro and zebrafish model
Enzymatic hydrolysis has been successfully used for the extraction of numerous biologically active components from a wide variety of natural sources. In the present study, velvet antler was subjected to the extraction process using Alcalase protease. We analyzed bioactive components, such as uronic acid, sulfated-glycosaminoglycans (sulfated-GAGs), and sialic acid, present in the velvet antler Alcalase hydrolysate (VAAH) and assessed their anti-inflammatory effects in zebrafish as well as in vitro using cell lines. VAAH mainly contained uronic acid (78.22 mg/g) and sulfated-GAGs (50.47 mg/g), while the amount of sialic acid was negligible (5.55 mg/g). VAAH inhibited the production of nitric oxide (NO) by lipopolysaccharide (LPS)-induced cells in a dosedependent manner and the inhibitory effect of VAAH on NO production was higher than that of hot water extracts. VAAH treatment also reduced the expression of inflammatory mediators such as nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, we evaluated anti-inflammatory effects of VAAH using LPS-stimulated zebrafish. Treatment with LPS significantly increased cell death, NO, and reactive oxygen species (ROS) levels in zebrafish. Notably, VAAH significantly inhibited the extent of LPS-stimulated cell death and generation of NO and ROS in zebrafish. These results suggest that VAAH alleviated inflammation and cell death by inhibiting the generation of ROS induced by LPS treatment. Thus, VAAH could be used as a potential natural remedy with a trong anti-inflammatory effect. Taken together, we believe that based on our present results, enzymatic hydrolysis of velvet antler may be an effective process to make antler products acceptable as elements of health foods and nutraceutical components with increased biological activity
A simple iterative independent component analysis algorithm for vibration source signal identification of complex structures
ABSTRACT:Independent Component Analysis (ICA), one of the blind source separation methods, can be applied for extracting unknown source signals only from received signals. This is accomplished by finding statistical independence of signal mixtures and has been successfully applied to myriad fields such as medical science, image processing, and numerous others. Nevertheless, there are inherent problems that have been reported when using this technique: insta- bility and invalid ordering of separated signals, particularly when using a conventional ICA technique in vibratory source signal identification of complex structures. In this study, a simple iterative algorithm of the conventional ICA has been proposed to mitigate these problems. The proposed method to extract more stable source signals having valid order includes an iterative and reordering process of extracted mixing matrix to reconstruct finally converged source signals, referring to the magnitudes of correlation coefficients between the intermediately separated signals and the signals measured on or nearby sources. In order to review the problems of the conventional ICA technique and to vali- date the proposed method, numerical analyses have been carried out for a virtual response model and a 30m class submarine model. Moreover, in order to investigate applicability of the proposed method to real problem of complex structure, an experiment has been carried out for a scaled submarine mockup. The results show that the proposed method could resolve the inherent problems of a conventional ICA technique
In Situ Self-Cross-Linkable, Long-Term Stable Hyaluronic Acid Filler by Gallol Autoxidation for Tissue Augmentation and Wrinkle Correction
Copyright © 2019 American Chemical Society.Injectable fillers mainly aim to augment tissue volume and correct wrinkles in cosmetic and plastic reconstructions. However, the development of long-lasting, injectable fillers with minimal complications of pain, toxicity, and displacement has been challenging because of the absence of reliable cross-linking chemistry. Here, we report a novel cross-linker-free injectable hydrogel formulated by autoxidation as a highly biocompatible, easily injectable, and long-term volumetrically stable filler agent. Self-cross-linkable hyaluronic acid (SC-HA) with gallol moieties could form a hydrogel via autoxidation of gallols in vivo without additional cross-linking agents. The gelation of SC-HA in situ after injection is accelerated by the self-production of oxygen species and endogenous peroxidase in vivo. The SC-HA filler does not require a high injection force, thus minimizing pain, bleeding, and tissue damage-associated complications. In addition, improved tissue adhesiveness of the SC-HA hydrogel by oxidized gallols (shear strength; 2 kPa) prevented displacement of the filler constructs from the injection site. The SC-HA filler retained its mechanical properties in vivo (600-700 Pa) for wrinkle correction and volumetric augmentation up to 1 year after injection. Overall, the performance of the SC-HA hydrogel as an injectable dermal filler was superior to that of commercially available, chemically cross-linked biphasic HA filler composites in terms of injectability, tissue adhesiveness, and long-term volumetric augmentation. Our injectable HA hydrogel with no need of cross-linkers provides a long-lasting filler that has clinical utility for cosmetic applications11sciescopu
Reconstituting ring-rafts in bud-mimicking topography of model membranes.
During vesicular trafficking and release of enveloped viruses, the budding and fission processes dynamically remodel the donor cell membrane in a protein- or a lipid-mediated manner. In all cases, in addition to the generation or relief of the curvature stress, the buds recruit specific lipids and proteins from the donor membrane through restricted diffusion for the development of a ring-type raft domain of closed topology. Here, by reconstituting the bud topography in a model membrane, we demonstrate the preferential localization of cholesterol- and sphingomyelin-enriched microdomains in the collar band of the bud-neck interfaced with the donor membrane. The geometrical approach to the recapitulation of the dynamic membrane reorganization, resulting from the local radii of curvatures from nanometre-to-micrometre scales, offers important clues for understanding the active roles of the bud topography in the sorting and migration machinery of key signalling proteins involved in membrane budding
Transcatheter Arterial Embolization as Treatment for a Life-Threatening Retroperitoneal Hemorrhage Complicating Heparin Therapy
Spontaneous retroperitoneal hemorrhage is a distinct clinical entity that can present in the absence of specific underlying pathology or trauma and is typically associated with anticoagulation therapy. We report a case of a 74-year-old female patient with a cerebral infarction related to atrial fibrillation who developed a spontaneous lumbar arterial hemorrhage complicating heparin therapy. The diagnosis was suggested by a computed tomography scan and confirmed by angiography. She was treated successfully with transcatheter embolization
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