Oscillation Phenomena in the disk around the massive black hole Sagittarius A*

We report the detection of radio QPOs with structure changes using the Very Long Baseline Array (VLBA) at 43 GHz. We found conspicuous patterned changes of the structure with P = 16.8 +- 1.4, 22.2 +- 1.4, 31.2 +- 1.5, 56.4 +- 6 min, very roughly in a 3:4:6:10 ratio. The first two periods show a rotating one-arm structure, while the P = 31.4 min shows a rotating 3-arm structure, as if viewed edge-on. At the central 50 microasec the P = 56.4 min period shows a double amplitude variation of those in its surroundings. Spatial distributions of the oscillation periods suggest that the disk of SgrA* is roughly edge-on, rotating around an axis with PA = -10 degree. Presumably, the observed VLBI images of SgrA* at 43 GHz retain several features of the black hole accretion disk of SgrA* in spite of being obscured and broadened by scattering of surrounding plasma.Comment: 24 pages, 20 figures, revised version submitted to MN main journal (2010, Jan., 12th

A Measurement of Proper Motions of SiO Maser Sources in the Galactic Center with the VLBA

We report on the high-precision astrometric observations of maser sources around the Galactic Center in the SiO J=1--0 v=1 and 2 lines with the VLBA during 2001 -- 2004. With phase-referencing interferometry referred to the radio continuum source Sgr A*, accurate positions of masers were obtained for three detected objects: IRS 10 EE (7 epochs), IRS 15NE (2 epochs), and SiO 6 (only 1 epoch). Because circumstellar masers of these objects were resolved into several components, proper motions for the maser sources were derived with several different methods. Combining our VLBA results with those of the previous VLA observations, we obtained the IRS 10EE proper motion of 76+-3 km s^{-1} (at 8 kpc) to the south relative to Sgr A*. Almost null proper motion of this star in the east--west direction results in a net transverse motion of the infrared reference frame of about 30+-9 km s^{-1} to the west relative to Sgr A*. The proper-motion data also suggests that IRS 10EE is an astrometric binary with an unseen massive companion.Comment: High-res. figures are available at ftp://ftp.nro.nao.ac.jp/nroreport/no656.pdf.gz . PASJ 60, No. 1 (2008) in pres

The Evaluation of Repetitive Overhead Movements in Heating Ventilation and Air Conditioning Technicians

Air conditioning technicians are the most non-fatally injured amongst construction workers. It has been identified that the shoulder is one of joints most commonly affected areas in industrial workers. While repetitive overhead movements have been evaluated in construction workers, it has not been described in air conditioning (AC) technicians. PURPOSE: To describe repetitive arm movement performed by AC technicians using inertial measurement unit (IMU) system, throughout a full work day. METHODS: An IMU is a small portable motion detection monitor that combines information from triaxial accelerometers, gyroscopes, and magnetometers to track translational movements. Six AC technicians participated on six separate days. Four IMU monitors were secured 2cm below the spinous process of the 7th cervical vertebrae (C7), the flat broad portion of the acromion process on the dominant arm, the posterior aspect of the dominant arm just superior of the elbow, and on the dorsal aspect of the dominant-side wrist to track multi-axial joint kinematics. An investigator then accompanied each participant to their work place to capture data and log when the participants were performing work-specific (e.g., mounting ceiling vents, installing and repairing air conditioning units), tasks and non-work-specific tasks. The arm activity was described separately and compared between times when the technicians performed work-specific and non-work specific tasks. Wilcoxon signed rank tests were used to compare the variables between times spent performing work-specific tasks and non-work-specific tasks. RESULTS: It was found that they spent 3.9±1.4 hours (41.6±15.6 %) performing work-specific tasks and 4.9±1.1 hours (53.8±11.9 %) performing non-work-specific tasks. The participants’ arm were elevated above 60° for 1.7±0.7 hours (18.5±8.0 %), and above 90° for 0.4±0.2 hours (4.2±2.6 %). It was also found that the participants spent 7.1 – 18.5% of their work shift with arm above 60° for more than 5 seconds and 1.0 – 4.9% above 90° for more than 5 seconds. CONCLUSION: These findings were similar to what has been reported in previous studies on electricians. Previous studies on manual laborers identified arm exposure as a risk factor for shoulder musculoskeletal disorders. Specifically, the greater time spent with arm maintained above 60° for more than 5 seconds has been correlated with shoulder pain. Our group of participants spent 7.1 – 18.5% of the work shift maintaining arm above 60° for more than 5 seconds, which is comparable to the ranges reported in a previous longitudinal study (2 – 21%). Considering that 27% of the participants in the previous study developed shoulder pain within 2.5 years of the follow up period, similar proportion of AC technicians may be at risk for developing pain and additional dysfunctional pathology

Change in thermal transitions and water uptakes of poly(l-lactic acid) blends upon hydrolytic degradation

AbstractThis article reports experimental data related to the research article entitled “Poly(malic acid-co-l-lactide) as a Superb Degradation Accelerator for Poly(l-lactic acid) at Physiological Conditions” (H.T. Oyama, D. Tanishima, S. Maekawa, 2016) [1]. Hydrolytic degradation of poly(l-lactic acid) (PLLA) blends with poly(aspartic acid-co-l-lactide) (PAL) and poly(malic acid-co-l-lactide) (PML) oligomers was investigated in a phosphate buffer solution at 40°C. It was found in the differential scanning calorimetry measurements that upon hydrolysis the cold crystallization temperature (Tc) and the melting temperature (Tm) significantly shifted to lower temperature. Furthermore, the hydrolysis significantly promoted water sorption in both blends

Comparison of the measured and modelled electron densities and temperatures in the ionosphere and plasmasphere during 20-30 January, 1993

International audienceWe present a comparison of the electron density and temperature behaviour in the ionosphere and plasmasphere measured by the Millstone Hill incoherent-scatter radar and the instruments on board of the EXOS-D satellite with numerical model calculations from a time-dependent mathematical model of the Earth's ionosphere and plasmasphere during the geomagnetically quiet and storm period on 20?30 January, 1993. We have evaluated the value of the additional heating rate that should be added to the normal photoelectron heating in the electron energy equation in the daytime plasmasphere region above 5000 km along the magnetic field line to explain the high electron temperature measured by the instruments on board of the EXOS-D satellite within the Millstone Hill magnetic field flux tube in the Northern Hemisphere. The additional heating brings the measured and modelled electron temperatures into agreement in the plasmasphere and into very large disagreement in the ionosphere if the classical electron heat flux along magnetic field line is used in the model. A new approach, based on a new effective electron thermal conductivity coefficient along the magnetic field line, is presented to model the electron temperature in the ionosphere and plasmasphere. This new approach leads to a heat flux which is less than that given by the classical Spitzer-Harm theory. The evaluated additional heating of electrons in the plasmasphere and the decrease of the thermal conductivity in the topside ionosphere and the greater part of the plasmasphere found for the first time here allow the model to accurately reproduce the electron temperatures observed by the instruments on board the EXOS-D satellite in the plasmasphere and the Millstone Hill incoherent-scatter radar in the ionosphere. The effects of the daytime additional plasmaspheric heating of electrons on the electron temperature and density are small at the F-region altitudes if the modified electron heat flux is used. The deviations from the Boltzmann distribution for the first five vibrational levels of N2(v) and O2(v) were calculated. The present study suggests that these deviations are not significant at the first vibrational levels of N2 and O2 and the second level of O2, and the calculated distributions of N2(v) and O2(v) are highly non-Boltzmann at vibrational levels v > 2. The resulting effect of N2(v > 0) and O2(v > 0) on NmF2 is the decrease of the calculated daytime NmF2 up to a factor of 1.5. The modelled electron temperature is very sensitive to the electron density, and this decrease in electron density results in the increase of the calculated daytime electron temperature up to about 580 K at the F2 peak altitude giving closer agreement between the measured and modelled electron temperatures. Both the daytime and night-time densities are not reproduced by the model without N2(v > 0) and O2(v > 0), and inclusion of vibrationally excited N2 and O2 brings the model and data into better agreement.Key words: Ionosphere (ionospheric disturbances; ionosphere-magnetosphere interactions; plasma temperature and density) <p style="line-height: 20px;"

p21 is decreased in polycystic kidney disease and leads to increased epithelial cell cycle progression: roscovitine augments p21 levels.

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is a common genetic disease with few treatment options other than renal replacement therapy. p21, a cyclin kinase inhibitor which has pleiotropic effects on the cell cycle, in many cases acts to suppress cell cycle progression and to prevent apoptosis. Because defects in cell cycle arrest and apoptosis of renal tubular epithelial cells occur in PKD, and in light of earlier reports that polycystin-1 upregulates p21 and that the cyclin-dependent kinase inhibitor roscovitine arrests progression in a mouse model, we asked whether (1) p21 deficiency might underlie ADPKD and (2) the mechanism of the salutary roscovitine effect on PKD involves p21.Methodsp21 levels in human and animal tissue samples as well as cell lines were examined by immunoblotting and/or immunohistochemisty. Apoptosis was assessed by PARP cleavage. p21 expression was attenuated in a renal tubular epithelial cell line by antisense methods, and proliferation in response to p21 attenuation and to roscovitine was assessed by the MTT assay.ResultsWe show that p21 is decreased in human as well as a non-transgenic rat model of ADPKD. In addition, hepatocyte growth factor, which induces transition from a cystic to a tubular phenotype, increases p21 levels. Furthermore, attenuation of p21 results in augmentation of cell cycle transit in vitro. Thus, levels of p21 are inversely correlated with renal tubular epithelial cell proliferation. Roscovitine, which has been shown to arrest progression in a murine model of PKD, increases p21 levels and decreases renal tubular epithelial cell proliferation, with no affect on apoptosis.ConclusionThe novelty of our study is the demonstration in vivo in humans and rat models of a decrement of p21 in cystic kidneys as compared to non-cystic kidneys. Validation of a potential pathogenetic model of increased cyst formation due to enhanced epithelial proliferation and apoptosis mediated by p21 suggests a mechanism for the salutary effect of roscovitine in ADPKD and supports further investigation of p21 as a target for future therapy

Slow relaxation to equipartition in spring-chain systems

In this study, one-dimensional systems of masses connected by springs, i.e., spring-chain systems, are investigated numerically. The average kinetic energy of chain-end particles of these systems is larger than that of other particles, which is similar to the behavior observed for systems made of masses connected by rigid links. The energetic motion of the end particles is, however, transient, and the system relaxes to thermal equilibrium after a while, where the average kinetic energy of each particle is the same, that is, equipartition of energy is achieved. This is in contrast to the case of systems made of masses connected by rigid links, where the energetic motion of the end particles is observed in equilibrium. The timescale of relaxation estimated by simulation increases rapidly with increasing spring constant. The timescale is also estimated using the Boltzmann-Jeans theory and is found to be in quite good agreement with that obtained by the simulation