A POSSIBLE BINARY SYSTEM OF A STELLAR REMNANT IN THE HIGH-MAGNIFICATION GRAVITATIONAL MICROLENSING EVENT OGLE-2007-BLG-514

Miyake, N.,Udalski, A.,Sumi, T.,Bennett, D. P.,Dong, S.,Street, R. A.,Greenhill, J.,Bond, I. A.,Gould, A.,Kubiak, M.,Szymań,ski, M. K.,Pietrzyń,ski, G.,Soszyń,ski, I.,Ulaczyk, K.,Wyrzyk IOP Publishing 2012 The Astrophysical journal Vol.752 No.2

<P>We report the extremely high-magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 +/- 0.007 and a projected separation of s = 0.072 +/- 0.001 in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D-L = 3.11 +/- 0.39 kpc and total mass M-L = 1.40 +/- 0.18 M-circle dot; this leads to the primary and secondary components having masses of M-1 = 1.06 +/- 0.13 M-circle dot and M-2 = 0.34 +/- 0.04 M-circle dot, respectively. The parallax model indicates that the binary lens system is likely constructed by the main-sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbital motion of the source around a companion) and parallax (q = 0.270 +/- 0.005, s = 0.083 +/- 0.001). The primary component of the binary lens is relatively massive, with M-1 = 0.9(-0.3)(+4.6) M-circle dot and it is at a distance of D-L = 2.6(-0.9)(+3.8) kpc. Given the secure mass ratio measurement, the companion mass is therefore M-2 = 0.2(-0.1)(+1.2) M-circle dot. The xallarap model implies that the primary lens is likely a stellar remnant, such as a white dwarf, a neutron star, or a black hole.</P>

MOA-2010-BLG-073L: AN M-DWARF WITH A SUBSTELLAR COMPANION AT THE PLANET/BROWN DWARF BOUNDARY

Street, R. A.,Choi, J.-Y.,Tsapras, Y.,Han, C.,Furusawa, K.,Hundertmark, M.,Gould, A.,Sumi, T.,Bond, I. A.,Wouters, D.,Zellem, R.,Udalski, A.,Snodgrass, C.,Horne, K.,Dominik, M.,Browne, P.,Kains, N.,Br IOP Publishing 2013 The Astrophysical journal Vol.763 No.1

<P>We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010 March 18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source light curve, we demonstrate that it is an irregular variable over timescales >200 days. Its dereddened color, (V - I)(S),(0), is 1.221 +/- 0.051 mag, and from our lens model we derive a source radius of 14.7 +/- 1.3 R-circle dot, suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q = 0.0654 +/- 0.0006. The Einstein crossing time of the event, t(E) = 44.3 +/- 0.1 days, was sufficiently long that the light curve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, D-L = 2.8 +/- 0.4 kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with M-L,M-1 = 0.16 +/- 0.03 M-circle dot, while the companion has M-L,M-2 = 11.0 +/- 2.0 M-J, putting it in the boundary zone between planets and brown dwarfs.</P>

A SUB-SATURN MASS PLANET, MOA-2009-BLG-319Lb

Miyake, N.,Sumi, T.,Dong, Subo,Street, R.,Mancini, L.,Gould, A.,Bennett, D. P.,Tsapras, Y.,Yee, J. C.,Albrow, M. D.,Bond, I. A.,Fouqué,, P.,Browne, P.,Han, C.,Snodgrass, C.,Finet, F.,Furusawa, K IOP Publishing 2011 The Astrophysical journal Vol.728 No.2

<P>We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K-or M-dwarf star in the inner Galactic disk or Galactic bulge. The high-cadence observations of the MOA-II survey discovered this microlensing event and enabled its identification as a high-magnification event approximately 24 hr prior to peak magnification. As a result, the planetary signal at the peak of this light curve was observed by 20 different telescopes, which is the largest number of telescopes to contribute to a planetary discovery to date. The microlensing model for this event indicates a planet-star mass ratio of q = (3.95 +/- 0.02) x 10(-4) and a separation of d = 0.97537 +/- 0.00007 in units of the Einstein radius. A Bayesian analysis based on the measured Einstein radius crossing time, t(E), and angular Einstein radius,theta(E), along with a standard Galactic model indicates a host star mass of M-L = 0.38(-0.18)(+0.34) M-circle dot and a planet mass of M-p = 50(-24)(+44)M(circle plus), which is half the mass of Saturn. This analysis also yields a planet-star three-dimensional separation of a = 2.4(-0.6)(+1.2) AU and a distance to the planetary system of D-L = 6.1(-1.2)(+1.1) kpc. This separation is similar to 2 times the distance of the snow line, a separation similar to most of the other planets discovered by microlensing.</P>

Degradation of Bradykinin, a Cardioprotective Substance, during a Single Passage through Isolated Rat-Heart

M. Ahmad,I. J. Zeitlin,J. R. Parratt,A. R. Pitt 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.3

(Received March 15, 2005) Angiotensin converting enzyme (ACE) inhibitors have cardioprotective effects in different species including human. This cardioprotective effect is mainly due to the inhibition of bradykinin (BK) degradation rather than inhibition of the conversion of angiotensin I to angiotensin II. Bradykinin, a nonapeptide, has been considered to be the potential target for various enzymes including ACE, neutral endopeptidase 24.11, carboxypeptidase M, carboxypeptidase N, proline aminopeptidase, endopeptidase 24.15, and meprin. In the present study, the coronary vascular beds of Sprague Dawley rat isolated hearts were perfused (single passage) with Krebs solution alone or with different concentrations of BK i.e. 2.75×10-10, 10-7, 10-6 and 10-5 M solution. Percent degradation of BK was determined by radioimmunoassay. The degradation products of BK after passing through the isolated rat-hearts were determined using RP-HPLC and mass spectroscopy. All the four doses of BK significantly decreased the perfusion pressure during their passage through the hearts. The percentage degradation of all four doses was decreased as the concentration of drug was increased, implying saturation of a fixed number of active sites involved in BK degradation. Bradykinin during a single passage through the hearts degraded to give [1-7]-BK as the major metabolite, and [1-8]-BK as a minor metabolite, detected on HPLC. Mass spectroscopy not only confirmed the presence of these two metabolites but also detected traces of [1-5]-BK and arginine. These findings showed that primarily ACE is the major cardiac enzyme involved in the degradation of bradykinin during a single passage through the coronary vascular of bed the healthy rat heart, while carboxypeptidase M may have a minor role.

A systematic investigation of the thermoelectric stability of Pt–Rh thermocouples between 1300 °C and 1500 °C

Pearce, J V,Edler, F,Elliott, C J,Greenen, A,Harris, P M,Izquierdo, C Garcia,Kim, Y-G,Martin, M J,Smith, I M,Tucker, D,Veltcheva, R I BUREAU INTERNATIONAL DES POIDS ET MESURES 2018 METROLOGIA -BERLIN- Vol.55 No.4

<P>By using a simple model to relate the electromotive force drift rate of Pt–Rh thermoelements to d<I>S</I>/d<I>c</I>, i.e. the sensitivity of the Seebeck coefficient, <I>S</I>, to rhodium mass fraction, <I>c</I>, the composition of the optimal pair of Pt–Rh wires that minimizes thermoelectric drift can be determined. The model has been applied to four multi-wire thermocouples each comprising 5 or 7 Pt–Rh wires of different composition. Two thermocouples were exposed to a temperature of around 1324 °C, one thermocouple to around 1492 °C, i.e. the melting points of the Co–C and Pd–C high temperature fixed points, respectively, and one thermocouple to a series of temperatures between 1315 °C and 1450 °C. The duration of exposure at each temperature was several thousand hours. By performing repeated calibrations <I>in situ</I> with the appropriate fixed point during the high temperature exposure, the drift performance has been quantified with high accuracy, entirely free from errors associated with thermoelectric homogeneity. By combining these results it is concluded that the Pt-40%Rh versus Pt-6%Rh is the most stable at the temperatures investigated. A preliminary reference function was determined and is presented.</P>

Fatigue crack effect on magnetic flux leakage for A283 grade C steel

M.I.M. Ahmad,A. Arifin,S. ABDULLAH,W.Z.W. Jusoh,S.S.K. Singh 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.6

This paper presents the characterization of fatigue crack in the A283 Grade C steel using the MMM method by identifying the effects of magnetic flux leakage towards the crack growth rate, da/dN, and crack length.The previous and current research on the relation between MMM parameters and fatigue crack effect is still unclear and requires specific analysis to validate that. This method is considered to be a passive magnetic method among other Non-Destructive Testing (NDT) methods. The tension-tension fatigue test was conducted with a testing frequency of 10 Hz with 4 kN loaded, meanwhile the MMM response signals were captured using a MMM instrument. A correlation between the crack growth rate and magnetic flux leakage produces a sigmoid shape curve with a constant values which present the gradient, m value is in the ranges of 1.4357 to 4.0506, and the y-intercept, log C in the ranges of 4×10<SUP>-7</SUP> to 0.0303. Moreover, a linear relation was obtained between the crack length and magnetic flux leakage which present the R-Squared values is at 0.830 to 0.978. Therefore, MMM method has their own capability to investigate and characterize the fatigue crack effects as a main source of fracture mechanism for ferrous-based materials.

OGLE-2014-BLG-0289: Precise Characterization of a Quintuple-peak Gravitational Microlensing Event

Udalski, A.,Han, C.,Bozza, V.,Gould, A.,Bond, I. A.,Mró,z, P.,Skowron, J.,Wyrzykowski, Ł.,Szymań,ski, M. K.,Soszyń,ski, I.,Ulaczyk, K.,Poleski, R.,Pietrukowicz, P.,Kozłowski, S.,Abe, F American Astronomical Society 2018 The Astrophysical journal Vol.853 No.1

<P>We present the analysis of the binary-microlensing event OGLE-2014-BLG-0289. The event light curve exhibits five very unusual peaks, four of which were produced by caustic crossings and the other by a cusp approach. It is found that the quintuple-peak features of the light curve provide tight constraints on the source trajectory, enabling us to precisely and accurately measure the microlensing parallax pi(E). Furthermore, the three resolved caustics allow us to measure the angular Einstein radius theta(E). From the combination of pE and qE, the physical lens parameters are uniquely determined. It is found that the lens is a binary composed of two M dwarfs with masses M-1 = 0.52 +/- 0.04 M-circle dot and M-2 = 0.42 +/- 0.03 M-circle dot separated in projection by a(perpendicular to) = 6.4 +/- 0.5 au. The lens is located in the disk with a distance of D-L = 3.3 +/- 0.3 kpc. The reason for the absence of a lensing signal in the Spitzer data is that the time of observation corresponds to the flat region of the light curve.</P>

OGLE-2011-BLG-0265Lb: A JOVIAN MICROLENSING PLANET ORBITING AN M DWARF

Skowron, J.,Shin, I.-G.,Udalski, A.,Han, C.,Sumi, T.,Shvartzvald, Y.,Gould, A.,Dominis Prester, D.,Street, R. A.,Jørgensen, U. G.,Bennett, D. P.,Bozza, V.,Szymań,ski, M. K.,Kubiak, M.,Pietrzy
IOP Publishing 2015 The Astrophysical journal Vol.804 No.1

<P>We report the discovery of a Jupiter-mass planet orbiting an M-dwarf star that gave rise to the microlensing event OGLE-2011-BLG-0265. Such a system is very rare among known planetary systems and thus the discovery is important for theoretical studies of planetary formation and evolution. High-cadence temporal coverage of the planetary signal, combined with extended observations throughout the event, allows us to accurately model the observed light curve. However, the final microlensing solution remains degenerate, yielding two possible configurations of the planet and the host star. In the case of the preferred solution, the mass of the planet is M-p = 0.9 +/- 0.3 M-J, and the planet is orbiting a star with a mass M = 0.22 +/- 0.06 M-circle dot. The second possible configuration (2 sigma away) consists of a planet with M-p = 0.6 +/- 0.3M(J) and host star with M = 0.14 +/- 0.06M(circle dot). The system is located in the Galactic disk 3-4 kpc toward the Galactic bulge. In both cases, with an orbit size of 1.5-2.0 AU, the planet is a 'cold Jupiter'-located well beyond the 'snow line' of the host star. Currently available data make the secure selection of the correct solution difficult, but there are prospects for lifting the degeneracy with additional follow-up observations in the future, when the lens and source star separate.</P>

MOA-2011-BLG-293Lb: A TEST OF PURE SURVEY MICROLENSING PLANET DETECTIONS

Yee, J. C.,Shvartzvald, Y.,Gal-Yam, A.,Bond, I. A.,Udalski, A.,Kozłowski, S.,Han, C.,Gould, A.,Skowron, J.,Suzuki, D.,Abe, F.,Bennett, D. P.,Botzler, C. S.,Chote, P.,Freeman, M.,Fukui, A.,Furusawa, K. IOP Publishing 2012 The Astrophysical journal Vol.755 No.2

<P>Because of the development of large-format, wide-field cameras, microlensing surveys are now able to monitor millions of stars with sufficient cadence to detect planets. These new discoveries will span the full range of significance levels including planetary signals too small to be distinguished from the noise. At present, we do not understand where the threshold is for detecting planets. MOA-2011-BLG-293Lb is the first planet to be published from the new surveys, and it also has substantial follow-up observations. This planet is robustly detected in survey+follow-up data (Delta chi(2) similar to 5400). The planet/host mass ratio is q = (5.3 similar to 0.2) x 10(-3). The best-fit projected separation is s = 0.548 +/- 0.005 Einstein radii. However, due to the s <-> s(-1) degeneracy, projected separations of s-1 are only marginally disfavored at Delta chi(2) = 3. A Bayesian estimate of the host mass gives M-L = 0.43(-0.17)(+0.27) M-circle dot, with a sharp upper limit of M-L < 1.2 M-circle dot from upper limits on the lens flux. Hence, the planet mass is m(p) = 2.4(-0.9)(+1.5) M-Jup, and the physical projected separation is either r(perpendicular to) similar or equal to 1.0 AU or r(perpendicular to) similar or equal to 3.4 AU. We show that survey data alone predict this solution and are able to characterize the planet, but the Delta chi(2) is much smaller (Delta chi(2) similar to 500) than with the follow-up data. The Delta chi(2) for the survey data alone is smaller than for any other securely detected planet. This event suggests a means to probe the detection threshold, by analyzing a large sample of events like MOA-2011-BLG-293, which have both follow-up data and high-cadence survey data, to provide a guide for the interpretation of pure survey microlensing data.</P>

Role of a highly conserved proline-126 in ThDP binding of Mycobacterium tuberculosis acetohydroxyacid synthase

Baig, I.A.,Gedi, V.,Lee, S.C.,Koh, S.H.,Yoon, M.Y. IPC Science and Technology Press ; Elsevier Scienc 2013 Enzyme and microbial technology Vol.53 No.4

Acetohydroxyacid synthase (AHAS) of Mycobacterium tuberculosis is a promising target for the development of anti-tuberculosis agents. With the absence of an available bacterial AHAS crystal structure, that of M. tuberculosis, site-directed mutagenesis has been a useful tool for determining its structural and functional features. In this study, a highly conserved proline residue (P126 of M. tuberculosis AHAS) was selected, and the possible role was evaluated by site-directed mutagenesis. P126 was replaced by valine, threonine, alanine, and glutamate to yield P126V, P126T, P126A, and P126E, respectively. All variants were expressed in their soluble forms in Escherichia coli and purified to near homogeneity. The molecular mass (SDS-PAGE) of the purified variants was ~68kDa, which is similar to that of wild-type AHAS. The P126V, P126T, and P126A variants exhibited significantly lower activity than wild-type AHAS, whereas P126E was inactive under the tested assay conditions. Furthermore, the P126V and P126T variants showed a significantly decreased preference toward pyruvate and ThDP as substrate and cofactor respectively, whereas the P126A showed similar kinetics to that of wild-type AHAS. Like in AHAS from yeast Saccharomyces cerevisiae (PDB ID: 1N0H), residue P126 is located in the ThDP binding pocket of M. tuberculosis AHAS homology model. Collectively, these results suggest that the conserved P126 plays a significant role in the ThDP binding of M. tuberculosis AHAS.