Evaluation of the Leap Motion Controller as a New Contact-Free Pointing Device

PubMed Central

Bachmann, Daniel; Weichert, Frank; Rinkenauer, Gerhard

2015-01-01

This paper presents a Fitts' law-based analysis of the user's performance in selection tasks with the Leap Motion Controller compared with a standard mouse device. The Leap Motion Controller (LMC) is a new contact-free input system for gesture-based human-computer interaction with declared sub-millimeter accuracy. Up to this point, there has hardly been any systematic evaluation of this new system available. With an error rate of 7.8 % for the LMC and 2.8% for the mouse device, movement times twice as large as for a mouse device and high overall effort ratings, the Leap Motion Controller's performance as an input device for everyday generic computer pointing tasks is rather limited, at least with regard to the selection recognition provided by the LMC. PMID:25609043

β Cephei and SPB stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Kołaczkowski, Z.; Pigulski, A.; Soszyński, I.; Udalski, A.; Szymański, M.; Kubiak, M.; Żebruń, K.; Pietrzyński, G.; Woźniak, P. R.; Szewczyk, O.; Wyrzykowski, L.; Ogle Team

2004-05-01

This is a progress report of the study of pulsating main-sequence stars in the LMC. Using the OGLE-II photometry supplemented by the MACHO photometry, we find 64 β Cephei stars in the LMC. Their periods are generally much longer than observed in the stars of this type in the Galaxy (the median value is 0.27 d compared with the 0.17 d in the Galaxy). In 20 stars with short periods attributable to the β Cephei-type instability, we also find modes with periods longer than ~0.4d. They are likely low-order g modes, which means that in these stars both kinds of variability, β Cephei and SPB, are observed. We also show examples of the multiperiodic SPB stars in the LMC, the first beyond our Galaxy.

Linear relations between leaf mass per area (LMA) and seasonal climate discovered through Linear Manifold Clustering (LMC)

NASA Astrophysics Data System (ADS)

Kiang, N. Y.; Haralick, R. M.; Diky, A.; Kattge, J.; Su, X.

2016-12-01

Leaf mass per area (LMA) is a critical variable in plant carbon allocation, correlates with leaf activity traits (photosynthetic activity, respiration), and is a controller of litterfall mass and hence carbon substrate for soil biogeochemistry. Recent advances in understanding the leaf economics spectrum (LES) show that LMA has a strong correlation with leaf life span, a trait that reflects ecological strategy, whereas physiological traits that control leaf activity scale with each other when mass-normalized (Osnas et al., 2013). These functional relations help reduce the number of independent variables in quantifying leaf traits. However, LMA is an independent variable that remains a challenge to specify in dynamic global vegetation models (DGVMs), when vegetation types are classified into a limited number of plant functional types (PFTs) without clear mechanistic drivers for LMA. LMA can range orders of magnitude across plant species, as well as vary within a single plant, both vertically and seasonally. As climate relations in combination with alternative ecological strategies have yet to be well identified for LMA, we have assembled 22,000 records of LMA spanning 0.004 - 33 mg/m2 from the numerous contributors to the TRY database (Kattge et al., 2011), with observations distributed over several climate zones and plant functional categories (growth form, leaf type, phenology). We present linear relations between LMA and climate variables, including seasonal temperature, precipitation, and radiation, as derived through Linear Manifold Clustering (LMC). LMC is a stochastic search technique for identifying linear dependencies between variables in high dimensional space. We identify a set of parsimonious classes of LMA-climate groups based on a metric of minimum description to identify structure in the data set, akin to data compression. The relations in each group are compared to Köppen-Geiger climate classes, with some groups revealing continuous linear relations between what might appear to be distinct classes. We discuss these results with regard to parameterization and evaluation of DGVMs with regard to plant diversity and representing the carbon cycle.

Herschel Key Program Heritage: a Far-Infrared Source Catalog for the Magellanic Clouds

NASA Astrophysics Data System (ADS)

Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta; Babler, Brian; Engelbracht, Charles W.; Gordon, Karl; Hony, Sacha; Misselt, Karl; Montiel, Edward; Okumura, Koryo; Panuzzo, Pasquale; Roman-Duval, Julia; Sauvage, Marc; Boyer, Martha L.; Chen, C.-H. Rosie; Indebetouw, Remy; Matsuura, Mikako; Oliveira, Joana M.; Srinivasan, Sundar; van Loon, Jacco Th.; Whitney, Barbara; Woods, Paul M.

2014-12-01

Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC due to both the SMC's smaller size and its lower dust content. The YSO candidate lists may be contaminated at low flux levels by background galaxies, and so we differentiate between sources with a high (“probable”) and moderate (“possible”) likelihood of being a YSO. There are 2493/425 probable YSO candidates in the LMC/SMC. Approximately 73% of the Herschel YSO candidates are newly identified in the LMC, and 35% in the SMC. We further identify a small population of dusty objects in the late stages of stellar evolution including extreme and post-asymptotic giant branch, planetary nebulae, and supernova remnants. These populations are identified by matching the HERITAGE catalogs to lists of previously identified objects in the literature. Approximately half of the LMC sources and one quarter of the SMC sources are too faint to obtain accurate ample FIR photometry and are unclassified.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta

Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from themore » Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC due to both the SMC's smaller size and its lower dust content. The YSO candidate lists may be contaminated at low flux levels by background galaxies, and so we differentiate between sources with a high (“probable”) and moderate (“possible”) likelihood of being a YSO. There are 2493/425 probable YSO candidates in the LMC/SMC. Approximately 73% of the Herschel YSO candidates are newly identified in the LMC, and 35% in the SMC. We further identify a small population of dusty objects in the late stages of stellar evolution including extreme and post-asymptotic giant branch, planetary nebulae, and supernova remnants. These populations are identified by matching the HERITAGE catalogs to lists of previously identified objects in the literature. Approximately half of the LMC sources and one quarter of the SMC sources are too faint to obtain accurate ample FIR photometry and are unclassified.« less

Surface modification effects on defect-related photoluminescence in colloidal CdS quantum dots.

PubMed

Lee, TaeGi; Shimura, Kunio; Kim, DaeGwi

2018-05-03

We investigated the effects of surface modification on the defect-related photoluminescence (PL) band in colloidal CdS quantum dots (QDs). A size-selective photoetching process and a surface modification technique with a Cd(OH)2 layer enabled the preparation of size-controlled CdS QDs with high PL efficiency. The Stokes shift of the defect-related PL band before and after the surface modification was ∼1.0 eV and ∼0.63 eV, respectively. This difference in the Stokes shifts suggests that the origin of the defect-related PL band was changed by the surface modification. Analysis by X-ray photoelectron spectroscopy revealed that the surface of the CdS QDs before and after the surface modification was S rich and Cd rich, respectively. These results suggest that Cd-vacancy acceptors and S-vacancy donors affect PL processes in CdS QDs before and after the surface modification, respectively.

The Multiplicity of Massive Stars: A High Angular Resolution Survey With The HST Fine Guidance Sensor

DTIC Science & Technology

2015-01-01

al. (2014), and of the Large Magellanic Cloud (LMC) Tarantula Nebula region by Sana et al. (2013b), demonstrate that the binary frequency may be »70...Monte-Carlo method to fit spectroscopic results for a large sample of O-type stars in the Tarantula Nebula region of the LMC, and they find a best fit

Neutral gas and diffuse interstellar bands in the LMC

NASA Technical Reports Server (NTRS)

Danks, Anthony C.; Penprase, Brian

1994-01-01

Tracing the dynamics of the neutral gas and observing diffuse interstellar bands in the LMC (Large Magellanic Cloud) was the focus of this study. The S/N values, a Quartz lamp exposure, a T horium Argon Comparision lamp exposure, and spectral plots for each star observed were taken. The stars observed were selected to sample the 30 Dor vicinty. NaI absorption profiles are included.

Evaluation of the Leap Motion Controller during the performance of visually-guided upper limb movements.

PubMed

Niechwiej-Szwedo, Ewa; Gonzalez, David; Nouredanesh, Mina; Tung, James

2018-01-01

Kinematic analysis of upper limb reaching provides insight into the central nervous system control of movements. Until recently, kinematic examination of motor control has been limited to studies conducted in traditional research laboratories because motion capture equipment used for data collection is not easily portable and expensive. A recently developed markerless system, the Leap Motion Controller (LMC), is a portable and inexpensive tracking device that allows recording of 3D hand and finger position. The main goal of this study was to assess the concurrent reliability and validity of the LMC as compared to the Optotrak, a criterion-standard motion capture system, for measures of temporal accuracy and peak velocity during the performance of upper limb, visually-guided movements. In experiment 1, 14 participants executed aiming movements to visual targets presented on a computer monitor. Bland-Altman analysis was conducted to assess the validity and limits of agreement for measures of temporal accuracy (movement time, duration of deceleration interval), peak velocity, and spatial accuracy (endpoint accuracy). In addition, a one-sample t-test was used to test the hypothesis that the error difference between measures obtained from Optotrak and LMC is zero. In experiment 2, 15 participants performed a Fitts' type aiming task in order to assess whether the LMC is capable of assessing a well-known speed-accuracy trade-off relationship. Experiment 3 assessed the temporal coordination pattern during the performance of a sequence consisting of a reaching, grasping, and placement task in 15 participants. Results from the t-test showed that the error difference in temporal measures was significantly different from zero. Based on the results from the 3 experiments, the average temporal error in movement time was 40±44 ms, and the error in peak velocity was 0.024±0.103 m/s. The limits of agreement between the LMC and Optotrak for spatial accuracy measures ranged between 2-5 cm. Although the LMC system is a low-cost, highly portable system, which could facilitate collection of kinematic data outside of the traditional laboratory settings, the temporal and spatial errors may limit the use of the device in some settings.

Evaluation of the Leap Motion Controller during the performance of visually-guided upper limb movements

PubMed Central

Gonzalez, David; Nouredanesh, Mina; Tung, James

2018-01-01

Kinematic analysis of upper limb reaching provides insight into the central nervous system control of movements. Until recently, kinematic examination of motor control has been limited to studies conducted in traditional research laboratories because motion capture equipment used for data collection is not easily portable and expensive. A recently developed markerless system, the Leap Motion Controller (LMC), is a portable and inexpensive tracking device that allows recording of 3D hand and finger position. The main goal of this study was to assess the concurrent reliability and validity of the LMC as compared to the Optotrak, a criterion-standard motion capture system, for measures of temporal accuracy and peak velocity during the performance of upper limb, visually-guided movements. In experiment 1, 14 participants executed aiming movements to visual targets presented on a computer monitor. Bland-Altman analysis was conducted to assess the validity and limits of agreement for measures of temporal accuracy (movement time, duration of deceleration interval), peak velocity, and spatial accuracy (endpoint accuracy). In addition, a one-sample t-test was used to test the hypothesis that the error difference between measures obtained from Optotrak and LMC is zero. In experiment 2, 15 participants performed a Fitts’ type aiming task in order to assess whether the LMC is capable of assessing a well-known speed-accuracy trade-off relationship. Experiment 3 assessed the temporal coordination pattern during the performance of a sequence consisting of a reaching, grasping, and placement task in 15 participants. Results from the t-test showed that the error difference in temporal measures was significantly different from zero. Based on the results from the 3 experiments, the average temporal error in movement time was 40±44 ms, and the error in peak velocity was 0.024±0.103 m/s. The limits of agreement between the LMC and Optotrak for spatial accuracy measures ranged between 2–5 cm. Although the LMC system is a low-cost, highly portable system, which could facilitate collection of kinematic data outside of the traditional laboratory settings, the temporal and spatial errors may limit the use of the device in some settings. PMID:29529064

The HERschel Inventory of the Agents of Galaxy Evolution in the Magellanic Clouds, a HERschel Open Time Key Program

NASA Technical Reports Server (NTRS)

Meixner, Margaret; Panuzzo, P.; Roman-Duval, J.; Engelbracht, C.; Babler, B.; Seale, J.; Hony, S.; Montiel, E.; Sauvage, M.; Gordon, K.;

The location of the peroneus longus tendon in the cuboid groove: sonographic study in various positions of the ankle-foot in asymptomatic volunteers.

PubMed

Choo, Hye Jung; Lee, Sun Joo; Huang, Brady K; Resnick, Donald L

2018-04-10

To evaluate the normal location of the peroneus longus tendon (PL) in the cuboid groove in various ankle-foot positions by ultrasonography in asymptomatic volunteers. Ultrasonographic assessment of the PL in the cuboid groove was performed in 20 feet of ten healthy volunteers. Each PL was examined in five ankle-foot positions (i.e., neutral, dorsiflexion, plantar-flexion, supination, and pronation). The PL location was qualitatively categorized as "inside" when the PL was entirely within the cuboid groove, as "overlying" when some part of the PL was perched on the cuboid tuberosity, and as "outside" when the PL was entirely on the cuboid tuberosity. For quantitative evaluation of the PL location, the distance between the PL and the cuboid groove was measured. The width of the cuboid groove was measured in the neutral position. The PL location did not significantly change with changes in the ankle-foot position. Qualitatively, an "overlying" PL was the most common type, regardless of the ankle-foot position. "Inside" PLs were found in only 35, 20, 30, 25, and 35% of feet in neutral, dorsiflexion, plantar-flexion, supination, and pronation positions, respectively. The quantitative PL location was also not significantly different among all ankle-foot positions and it was significantly negatively correlated with the cuboid groove width. In healthy volunteers, 65% or more of the PLs were partially or completely located outside of the cuboid groove, regardless of the ankle-foot position. The PL location relative to the cuboid groove was related to the cuboid groove width.

LM1-64: a Newly Reported Lmc-Pn with WR Nucleus

NASA Astrophysics Data System (ADS)

Pena, M.; Olguin, L.; Ruiz, M. T.; Torres-Peimbert, S.

1993-05-01

The object LM1-64 was reported by Lindsay & Mullan (1963, Irish Astron. J., 5, 51) as a probable PN in the LMC. Optical and UV spectra taken by us confirm that suggestion. LM1-64 is a high excitation planetary nebulae which shows evidence of having a WC central star. Broad stellar emission at lambda 4650 is detected in the optical spectrum obtained with the CTIO 4m telescope, in 1989. A UV spectrum in the range from 1200 Angstroms to 2000 Angstroms was obtained with IUE in 1990. We have measured all the emission line fluxes available and determined values for the physical conditions and chemical abundances of the nebular ionized gas. The derived values are T(OIII) = 14000K, log He/H = 11.05, log C/H = 9.48, log O/H = 8.55 and log Ne/H = 7.94. LM1-64 shows a large C enhancement in the envelope as result of the central star activity, while He, O and Ne are comparable to the average values reported for the LMC-PNe (Monk, Barlow & Clegg, 1988, MNRAS, 234, 583). We have estimated the He II Zanstra temperature of the central star to be ~ 80,000 K. This temperature is much higher than the values reported for the known LMC-PNe with WR nucleus that Monk et al. have classified as W4 to W8. The only other high temperature WR nucleus in a LMC-PN is N66 which recently showed evidence of undergoing a WR episode (Torres-Peimbert, Ruiz, Peimbert & Pe\\ na, 1993, IAU Symp. 155, eds. A. Acker & R. Weinberger, in press).

THERMAL PRESSURES IN THE INTERSTELLAR MEDIUM OF THE MAGELLANIC CLOUDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welty, Daniel E.; York, Donald G.; Lauroesch, James T.

2016-04-20

We discuss the thermal pressures ( n {sub H} T ) in predominantly cold, neutral interstellar gas in the Magellanic Clouds, derived from analyses of the fine-structure excitation of neutral carbon, as seen in high-resolution Hubble Space Telescope /Space Telescope Imaging Spectrograph spectra of seven diverse sight lines in the LMC and SMC. Detailed fits to the line profiles of the absorption from C i, C i*, and C i** yield consistent column densities for the three to six C i multiplets detected in each sight line. In the LMC and SMC, N (C i{sub tot}) is consistent with Galacticmore » trends versus N (Na i) and N (CH), but is slightly lower versus N (K i) and N (H{sub 2}). As for N (Na i) and N (K i), N (C i{sub tot}) is generally significantly lower, for a given N (H{sub tot}), in the LMC and (especially) in the SMC, compared to the local Galactic relationship. For the LMC and SMC components with well-determined column densities for C i, C i*, and C i**, the derived thermal pressures are typically factors of a few higher than the values found for most cold, neutral clouds in the Galactic ISM. Such differences are consistent with the predictions of models for clouds in systems (like the LMC and SMC) that are characterized by lower metallicities, lower dust-to-gas ratios, and enhanced radiation fields—where higher pressures are required for stable cold, neutral clouds. The pressures may be further enhanced by energetic activity (e.g., due to stellar winds, star formation, and/or supernova remnants) in several of the regions probed by these sight lines. Comparisons are made with the C i observed in some quasar absorption-line systems.« less

Operator assistant to support deep space network link monitor and control

NASA Technical Reports Server (NTRS)

Cooper, Lynne P.; Desai, Rajiv; Martinez, Elmain

1992-01-01

Preparing the Deep Space Network (DSN) stations to support spacecraft missions (referred to as pre-cal, for pre-calibration) is currently an operator and time intensive activity. Operators are responsible for sending and monitoring several hundred operator directivities, messages, and warnings. Operator directives are used to configure and calibrate the various subsystems (antenna, receiver, etc.) necessary to establish a spacecraft link. Messages and warnings are issued by the subsystems upon completion of an operation, changes of status, or an anomalous condition. Some points of pre-cal are logically parallel. Significant time savings could be realized if the existing Link Monitor and Control system (LMC) could support the operator in exploiting the parallelism inherent in pre-cal activities. Currently, operators may work on the individual subsystems in parallel, however, the burden of monitoring these parallel operations resides solely with the operator. Messages, warnings, and directives are all presented as they are received; without being correlated to the event that triggered them. Pre-cal is essentially an overhead activity. During pre-cal, no mission is supported, and no other activity can be performed using the equipment in the link. Therefore, it is highly desirable to reduce pre-cal time as much as possible. One approach to do this, as well as to increase efficiency and reduce errors, is the LMC Operator Assistant (OA). The LMC OA prototype demonstrates an architecture which can be used in concert with the existing LMC to exploit parallelism in pre-cal operations while providing the operators with a true monitoring capability, situational awareness and positive control. This paper presents an overview of the LMC OA architecture and the results from initial prototyping and test activities.

Fourier Analysis of First-Overtone RR Lyrae Variables in the LMC

NASA Astrophysics Data System (ADS)

Clement, C. M.; Muzzin, A. V.; Rowe, J. F.; MACHO Collaboration

2002-05-01

Simon's (1989, ApJ, 343, L17) Fourier decomposition technique has been applied to the V magnitudes of the first-overtone RR Lyrae (RR1) variables in 16 LMC fields observed by the MACHO collaboration. The Fourier coefficients R21 and φ 31 derived for these stars have been compared with the coefficients of RR1 variables in the galactic globular clusters Omega Centauri, M2, M3, M5, M68, M107 (NGC 6171) and NGC 6441. Our analysis indicates that the majority of the LMC RR1 variables have coefficients similar to those in the Oosterhoff type I (OoI) clusters M3 and M5 and to the OoI variables in Omega Centauri. In a study of hydrodynamic pulsation models of first overtone RR Lyrae variables, Simon & Clement (1993, ApJ, 410, 526) found that the Fourier phase parameter φ 31 depends essentially on mass and luminosity. From this, we conclude that the masses and luminosities of most of the RR1 variables in the LMC are comparable to those of the OoI RR1 variables in Omega Centauri, M3 and M5, a fact that should be considered when RR Lyrae variables are used for determining the distance to the LMC. The MACHO collaboration includes C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennet, K. H. Cook, A. J. Drake, K. C. Freeman, M. Geha, K. Griest, M. J. Lehner, S. L. Marshall, D. Minniti, C. A. Nelson, B. A. Peterson, P. Popowski, M. R. Pratt, P. J. Quinn, C. W. Stubbs, W. Sutherland, T. Vandehel and D. L. Welch. This research has been supported in part by the Natural Sciences and Engineering Research Council of Canada.

Response of the Milky Way's disc to the Large Magellanic Cloud in a first infall scenario

NASA Astrophysics Data System (ADS)

Laporte, Chervin F. P.; Gómez, Facundo A.; Besla, Gurtina; Johnston, Kathryn V.; Garavito-Camargo, Nicolas

2018-01-01

We present N-body and hydrodynamical simulations of the response of the Milky Way's baryonic disc to the presence of the Large Magellanic Cloud during a first infall scenario. For a fiducial Galactic model reproducing the gross properties of the Galaxy, we explore a set of six initial conditions for the Large Magellanic Cloud (LMC) of varying mass which all evolve to fit the measured constraints on its current position and velocity with respect to the Galactic Centre. We find that the LMC can produce strong disturbances - warping of the stellar and gaseous discs - in the Galaxy, without violating constraints from the phase-space distribution of stars in the Solar Neighbourhood. All models correctly reproduce the phases of the warp and its antisymmetrical shape about the disc's mid-plane. If the warp is due to the LMC alone, then the largest mass model is favoured (2.5 × 1011 M⊙). Still, some quantitative discrepancies remain, including deficits in height of ΔZ = 0.7 kpc at R = 22 kpc and ΔZ = 0.7 kpc at R = 16 kpc. This suggests that even higher infall masses for the LMC's halo are allowed by the data. A comparison with the vertical perturbations induced by a heavy Sagittarius dSph model (1011 M⊙) suggest that positive interference with the LMC warp is expected at R = 16 kpc. We conclude that the vertical structure of the Galactic disc beyond the Solar Neighbourhood may jointly be shaped by its most massive satellites. As such, the current structure of the Milky Way suggests we are seeing the process of disc heating by satellite interactions in action.

Proper motion separation of Be star candidates in the Magellanic Clouds and the Milky Way

NASA Astrophysics Data System (ADS)

Vieira, Katherine; García-Varela, Alejandro; Sabogal, Beatriz

2017-08-01

We present a proper motion investigation of a sample of Be star candidates towards the Magellanic Clouds, which has resulted in the identification of separate populations, in the Galactic foreground and in the Magellanic background. Be stars are broadly speaking B-type stars that have shown emission lines in their spectra. In this work, we studied a sample of 2446 and 1019 Be star candidates towards the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), respectively, taken from the literature and proposed as possible Be stars due to their variability behaviour in the OGLE-II I band. JHKs magnitudes from the InfraRed Survey Facility catalogue and proper motions from the Southern Proper Motion 4 catalogue were obtained for 1188 and 619 LMC and SMC Be stars candidates, respectively. Colour-colour and vector-point diagrams were used to identify different populations amongst the Be star candidates. In the LMC sample, two populations with distinctive infrared colours and kinematics were found, the bluer sample is consistent with being in the LMC and the redder one with belonging to the Milky Way disc. This settles the nature of the redder sample that had been described in previous publications as a possible unknown subclass of stars amongst the Be candidates in the LMC. In the SMC sample, a similar but less evident result was obtained, since this apparent unknown subclass was not seen in this galaxy. We confirm that in the selection of Be stars by their variability, although generally successful, there is a higher risk of contamination by Milky Way objects towards redder B - V and V - I colours.

Development of a new assessment tool for cervical myelopathy using hand-tracking sensor: Part 1: validity and reliability.

PubMed

Alagha, M Abdulhadi; Alagha, Mahmoud A; Dunstan, Eleanor; Sperwer, Olaf; Timmins, Kate A; Boszczyk, Bronek M

2017-04-01

To assess the reliability and validity of a hand motion sensor, Leap Motion Controller (LMC), in the 15-s hand grip-and-release test, as compared against human inspection of an external digital camera recording. Fifty healthy participants were asked to fully grip-and-release their dominant hand as rapidly as possible for two trials with a 10-min rest in-between, while wearing a non-metal wrist splint. Each test lasted for 15 s, and a digital camera was used to film the anterolateral side of the hand on the first test. Three assessors counted the frequency of grip-and-release (G-R) cycles independently and in a blinded fashion. The average mean of the three was compared with that measured by LMC using the Bland-Altman method. Test-retest reliability was examined by comparing the two 15-s tests. The mean number of G-R cycles recorded was: 47.8 ± 6.4 (test 1, video observer); 47.7 ± 6.5 (test 1, LMC); and 50.2 ± 6.5 (test 2, LMC). Bland-Altman indicated good agreement, with a low bias (0.15 cycles) and narrow limits of agreement. The ICC showed high inter-rater agreement and the coefficient of repeatability for the number of cycles was ±5.393, with a mean bias of 3.63. LMC appears to be valid and reliable in the 15-s grip-and-release test. This serves as a first step towards the development of an objective myelopathy assessment device and platform for the assessment of neuromotor hand function in general. Further assessment in a clinical setting and to gauge healthy benchmark values is warranted.

Plumbagin suppresses dendritic cell functions and alleviates experimental autoimmune encephalomyelitis.

PubMed

Zhang, Kai; Ge, Zhenzhen; Da, Yurong; Wang, Dong; Liu, Ying; Xue, Zhenyi; Li, Yan; Li, Wen; Zhang, Lijuan; Wang, Huafeng; Zhang, Huan; Peng, Meiyu; Hao, Junwei; Yao, Zhi; Zhang, Rongxin

2014-08-15

Plumbagin (PL, 5-hydroxy-2-methyl-1,4-naphthoquinone) is a herbal compound derived from medicinal plants of the Droseraceae, Plumbaginaceae, Dioncophyllaceae, and Ancistrocladaceae families. Reports have shown that PL exerts immunomodulatory activity and may be a novel drug candidate for immune-related disease therapy. However, its effects on dendritic cells (DCs), the most potent antigen-presenting cells (APCs), remain unclear. In this study, we demonstrate that PL inhibits the differentiation, maturation, and function of human monocyte-derived DCs. PL can also restrict the expression of Th1- and Th17-polarizing cytokines in mDC. In addition, PL suppresses DCs both in vitro and in vivo, as demonstrated by its effects on the mouse DC line DC2.4 and mice with experimental autoimmune encephalomyelitis (EAE), respectively. Notably, PL ameliorated the clinical symptoms of EAE, including central nervous system (CNS) inflammation and demyelination. Our results demonstrate the immune suppressive and anti-inflammatory properties of PL via its effects on DCs and suggest that PL could be a potential treatment for DC-related autoimmune and inflammatory diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

Exploring the nature and synchronicity of early cluster formation in the Large Magellanic Cloud - III. Horizontal branch morphology

NASA Astrophysics Data System (ADS)

Wagner-Kaiser, R.; Mackey, Dougal; Sarajedini, Ata; Cohen, Roger E.; Geisler, Doug; Yang, Soung-Chul; Grocholski, Aaron J.; Cummings, Jeffrey D.

2018-03-01

We leverage new high-quality data from Hubble Space Telescope program GO-14164 to explore the variation in horizontal branch morphology among globular clusters in the Large Magellanic Cloud (LMC). Our new observations lead to photometry with a precision commensurate with that available for the Galactic globular cluster population. Our analysis indicates that, once metallicity is accounted for, clusters in the LMC largely share similar horizontal branch morphologies regardless of their location within the system. Furthermore, the LMC clusters possess, on average, slightly redder morphologies than most of the inner halo Galactic population; we find, instead, that their characteristics tend to be more similar to those exhibited by clusters in the outer Galactic halo. Our results are consistent with previous studies, showing a correlation between horizontal branch morphology and age.

Multiwavelength Modeling of Nove Atmospheres

NASA Technical Reports Server (NTRS)

Huschildt, P. H.

2001-01-01

LMC 1988 #1 was a slow, CO type, dust forming classical nova. It was the first extragalactic nova to be observed with the IUE satellite. We have successfully fitted observed ultraviolet and optical spectra of LMC 1988 #1 taken within the first two months of its outburst (when the atmosphere was still optically thick) with synthetic spectra computed using PHOENIX nova model atmospheres. The synthetic spectra reproduce most of the features seen in the spectra and provide V band magnitudes consistent with the observed light curve. The fits are improved by increasing the CNO abundances to 10 times the solar values. The bolometric luminosity of LMC 1988 #1 was approximately constant at 2 x 10(exp 38) ergs per second at a distance of 47.3 kpc for the first 2 months of the outburst until the formation of the dust shell.

Discovery of a Possible Symbiotic Binary in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Mathew, Blesson; Reid, Warren A.; Mennickent, R. E.; Banerjee, D. P. K.

2017-12-01

We report the discovery of a possible symbiotic star, in the Large Magellanic Cloud (LMC). The object under consideration here, designated as RP 870, was detected during the course of a comprehensive H$\\alpha$ survey of the LMC by Reid & Parker (2012). The spectrum of RP 870 showed high ionization emission lines of He I, He II and [O III] and molecular absorption bands of TiO $\\lambda$$\\lambda$6180, 7100. The collective signatures of a hot component (high excitation/ionization lines) and of a cool component (TiO molecular bands) are seen in RP 870, from which we propose it as a symbiotic star. Since known symbiotic systems are rare in the LMC, possibly less than a dozen are known, we thought the present detection to be interesting enough to be reported.

Uncertainties in the interstellar extinction curve and the Cepheid distance to M101

NASA Astrophysics Data System (ADS)

Nataf, David M.

2015-05-01

I revisit the Cepheid-distance determination to the nearby spiral galaxy M101 (Pinwheel Galaxy) of Shappee & Stanek, in light of several recent investigations questioning the shape of the interstellar extinction curve at λ ≈ 8000 Å (i.e. the I band). I find that the relatively steep extinction ratio AI/E(V - I) = 1.1450 from Fitzpatrick & Massa is slightly favoured relative to AI/E(V - I) = 1.2899 from Fitzpatrick and significantly favoured relative the historically canonical value of AI/E(V - I) = 1.4695, from Cardelli et al. The steeper extinction curves, with lower values of AI/E(V - I), yield fits with reduced scatter, metallicity dependences to the dereddened Cepheid luminosities that are closer to values inferred in the Local Group, and that are less sensitive to the choice of reddening cut imposed in the sample selection. The increase in distance modulus to M101 when using the preferred extinction curve is Δμ ˜ 0.06 mag, resulting in the estimate of the distance modulus to M101 relative to the LMC is ΔμLMC ≈ 10.72 ± 0.03 (stat). The best-fitting metallicity dependence is dMI/d{[O/H]} ≈ (-0.38 ± 0.14 (stat)) mag dex-1.

Observation of X-ray eclipses from LMC X-4

NASA Technical Reports Server (NTRS)

Li, F.; Rappaport, S.; Epstein, A.

1978-01-01

Observations made with the Rotation Modulation Collimator system (RMC) have revealed that X-ray source X-4 in the Large Magellanic Cloud (LMC X-4) is most likely part of a binary system. An analysis of the star's coordinates is presented, with attention given to orbital period and flux intensity variations. Stellar mass and orbital inclination angle are estimated for both X-4 and its companion star.

Differential gene expression is not required for facultative sex allocation: a transcriptome analysis of brain tissue in the parasitoid wasp Nasonia vitripennis

PubMed Central

Boulton, Rebecca A.; Green, Jade; Trivedi, Urmi; Pannebakker, Bart A.; Ritchie, Michael G.; Shuker, David M.

2018-01-01

Whole-transcriptome technologies have been widely used in behavioural genetics to identify genes associated with the performance of a behaviour and provide clues to its mechanistic basis. Here, we consider the genetic basis of sex allocation behaviour in the parasitoid wasp Nasonia vitripennis. Female Nasonia facultatively vary their offspring sex ratio in line with Hamilton's theory of local mate competition (LMC). A single female or ‘foundress’ laying eggs on a patch will lay just enough sons to fertilize her daughters. As the number of ‘foundresses’ laying eggs on a patch increases (and LMC declines), females produce increasingly male-biased sex ratios. Phenotypic studies have revealed the cues females use to estimate the level of LMC their sons will experience, but our understanding of the genetics underlying sex allocation is limited. Here, we exposed females to three foundress number conditions, i.e. three LMC conditions, and allowed them to oviposit. mRNA was extracted from only the heads of these females to target the brain tissue. The subsequent RNA-seq experiment confirmed that differential gene expression is not associated with the response to sex allocation cues and that we must instead turn to the underlying neuroscience to reveal the underpinnings of this impressive behavioural plasticity. PMID:29515880

ASCA Observations of LMC SNRS

NASA Technical Reports Server (NTRS)

Hughes, John P.

1999-01-01

We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K(alpha) emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, & Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based an these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last approximately 1500 yr came from Type Ia SNs.

Human platelet lysate in mesenchymal stromal cell expansion according to a GMP grade protocol: a cell factory experience.

PubMed

Becherucci, Valentina; Piccini, Luisa; Casamassima, Serena; Bisin, Silvia; Gori, Valentina; Gentile, Francesca; Ceccantini, Riccardo; De Rienzo, Elena; Bindi, Barbara; Pavan, Paola; Cunial, Vanessa; Allegro, Elisa; Ermini, Stefano; Brugnolo, Francesca; Astori, Giuseppe; Bambi, Franco

2018-05-02

The use of platelet lysate (PL) for the ex-vivo expansion of mesenchymal stromal/stem cells (MSCs) was initially proposed by Doucet et al. in 2005, as an alternative to animal serum. Moreover, regulatory authorities discourage the use of fetal bovine serum (FBS) or other animal derivatives, to avoid risk of zoonoses and xenogeneic immune reactions. Even if many studies investigated PL composition, there still are some open issues related to its use in ex-vivo MSC expansion, especially according to good manufacturing practice (GMP) grade protocols. As an authorized cell factory, we report our experience using standardized PL produced by Azienda Ospedaliero Universitaria Meyer Transfusion Service for MSC expansion according to a GMP grade clinical protocol. As suggested by other authors, we performed an in-vitro test on MSCs versus MSCs cultured with FBS that still represents the best way to test PL batches. We compared 12 MSC batches cultured with DMEM 5% PL with similar batches cultured with DMEM 10% FBS, focusing on the MSC proliferation rate, MSC surface marker expression, MSC immunomodulatory and differentiation potential, and finally MSC relative telomere length. Results confirmed the literature data as PL increases cell proliferation without affecting the MSC immunophenotype, immunomodulatory potential, differentiation potential and relative telomere length. PL can be considered a safe alternative to FBS for ex-vivo expansion of MSC according to a GMP grade protocol. Our experience confirms the literature data: a large number of MSCs for clinical applications can be obtained by expansion with PL, without affecting the MSC main features. Our experience underlines the benefits of a close collaboration between the PL producers (transfusion service) and the end users (cell factory) in a synergy of skills and experiences that can lead to standardized PL production.

Time-resolved photoluminescence characterization of oxygen-related defect centers in AlN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genji, Kumihiro; Uchino, Takashi, E-mail: uchino@kobe-u.ac.jp

2016-07-11

Time-resolved photoluminescence (PL) spectroscopy has been employed to investigate the emission characteristics of oxygen-related defects in AlN in the temperature region from 77 to 500 K. Two PL components with different decay constants are observed in the near-ultraviolet to visible regions. One is the PL component with decay time of <10 ns and its peak position shifts to longer wavelengths from ∼350 to ∼500 nm with increasing temperature up to 500 K. This PL component is attributed to the radiative relaxation of photoexcited electrons from the band-edge states to the ground state of the oxygen-related emission centers. In the time region from tens tomore » hundreds of nanoseconds, the second PL component emerges in the wavelength region from 300 to 400 nm. The spectral shape and the decay profiles are hardly dependent on temperature. This temperature-independent PL component most likely results from the transfer of photoexcited electrons from the band-edge states to the localized excited state of the oxygen-related emission centers. These results provide a detailed insight into the radiative relaxation processes of the oxygen-related defect centers in AlN immediately after the photoexcitation process.« less

Detection of a Very Bright Source Close to the LMC Supernova SN 1987A: Erratum

NASA Astrophysics Data System (ADS)

Nisenson, P.; Papaliolios, C.; Karovska, M.; Noyes, R.

1988-01-01

In the Letter "Detection of a Very Bright Source Close to the LMC Supernova SN 1987A" by P. Nisenson, C. Papaliolios, M. Karovska, and R. Noyes (1987 Ap. J. [Letters], 320, L15), two of the figure labels for Figure 1 were inadvertently transposed in the production process. A corrected version of the figure appears as Plate L4. The Journal regrets the error.

THE ARAUCARIA PROJECT: ON THE TIP OF THE RED GIANT BRANCH DISTANCE DETERMINATION TO THE MAGELLANIC CLOUDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Górski, Marek; Gieren, Wolfgang; Catelan, Márcio

2016-06-01

We present a precise optical and near-infrared determination of the tip of the red giant branch (TRGB) brightness in the Large and Small Magellanic Clouds (respectively, LMC and SMC). The commonly used calibrations of the absolute magnitude of the TRGB lead to an overestimation of the distance to the LMC and SMC in the K band, and an underestimation of the distance in the optical I band for both galaxies. Reported discrepancies are at the level of 0.2 mag, with respect to the very accurate distance determinations to both MCs based on late-type eclipsing binaries. The differential distances between themore » LMC and SMC obtained in the J and K bands, and for the bolometric brightness are consistent with each other, and with the results obtained from eclipsing binaries and other distance indicators.« less

Numerical Simulation and Experimental Casting of Nickel-Based Single-Crystal Superalloys by HRS and LMC Directional Solidification Processes

NASA Astrophysics Data System (ADS)

Yan, Xuewei; Wang, Run'nan; Xu, Qingyan; Liu, Baicheng

2017-04-01

Mathematical models for dynamic heat radiation and convection boundary in directional solidification processes are established to simulate the temperature fields. Cellular automaton (CA) method and Kurz-Giovanola-Trivedi (KGT) growth model are used to describe nucleation and growth. Primary dendritic arm spacing (PDAS) and secondary dendritic arm spacing (SDAS) are calculated by the Ma-Sham (MS) and Furer-Wunderlin (FW) models respectively. The mushy zone shape is investigated based on the temperature fields, for both high-rate solidification (HRS) and liquid metal cooling (LMC) processes. The evolution of the microstructure and crystallographic orientation are analyzed by simulation and electron back-scattered diffraction (EBSD) technique, respectively. Comparison of the simulation results from PDAS and SDAS with experimental results reveals a good agreement with each other. The results show that LMC process can provide both dendritic refinement and superior performance for castings due to the increased cooling rate and thermal gradient.

VizieR Online Data Catalog: LMC PNe multiwavelength photometry (Reid, 2014)

NASA Astrophysics Data System (ADS)

Reid, W. A.

2017-07-01

Using the 2MASS 6x catalogue for the LMC (Cutri et al. 2003, Cat. II/246; 2012, Cat. VII/233), magnitudes were obtained for 274 PNe in J, 269 in H and 263 in Ks. To increase the number of detections available for comparison, magnitudes were also obtained from the InfraRed Survey Facility (IRSF) Magellanic Clouds Point Source Catalogue (Kato et al., 2007, Cat. II/288). The 3.6, 4.5, 5.8 and 8um bands were obtained with the IRAC on board Spitzer. This study used the archival data from the Spitzer legacy programme SAGE (Meixner et al., 2006, Cat. J/AJ/132/2268) which mapped the central 7x7deg2 area of the LMC. The MIPS data were also obtained from both the Hora et al. (2008, Cat. J/AJ/135/726) and Gruendl & Chu (2009, Cat. J/ApJS/184/172) studies. (3 data files).

Monitoring methods and predictive models for water status in Jonathan apples.

PubMed

Trincă, Lucia Carmen; Căpraru, Adina-Mirela; Arotăriţei, Dragoş; Volf, Irina; Chiruţă, Ciprian

2014-02-01

Evaluation of water status in Jonathan apples was performed for 20 days. Loss moisture content (LMC) was carried out through slow drying of wholes apples and the moisture content (MC) was carried out through oven drying and lyophilisation for apple samples (chunks, crushed and juice). We approached a non-destructive method to evaluate LMC and MC of apples using image processing and multilayer neural networks (NN) predictor. We proposed a new simple algorithm that selects the texture descriptors based on initial set heuristically chosen. Both structure and weights of NN are optimised by a genetic algorithm with variable length genotype that led to a high precision of the predictive model (R(2)=0.9534). In our opinion, the developing of this non-destructive method for the assessment of LMC and MC (and of other chemical parameters) seems to be very promising in online inspection of food quality. Copyright © 2013 Elsevier Ltd. All rights reserved.

The deep levels in InGaAlP epilayers grown by metalorganic chemical vapor deposition using tertiarybutylphosphine

NASA Astrophysics Data System (ADS)

Izumiya, T.; Ishikawa, H.; Mashita, M.

1994-12-01

InGaAlP epilayers and double-hetero structure light emitting diodes (LEDs) were grown by metalorganic chemical vapor deposition (MOCVD) using tertiarybutylphosphine (TBP). The photoluminescence (PL) intensities were low compared with the epilayer grown using PH 3, and depended markedly on the TBP synthesis lots. Deep levels, were studied and two oxygen related levels were observed in the epilayers with small PL intensities. An intimate relation between the deep levels and the photoluminescence (PL) intensity has been found. A larger TBP flow rate reduced the deep level concentrations and improved the PL intensity.

The Optical Gravitational Lensing Experiment. Catalog of RR Lyr Stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Soszynski, I.; Udalski, A.; Szymanski, M.; Kubiak, M.; Pietrzynski, G.; Wozniak, P.; Zebrun, K.; Szewczyk, O.; Wyrzykowski, L.

2003-06-01

We present the catalog of RR Lyr stars discovered in a 4.5 square degrees area in the central parts of the Large Magellanic Cloud (LMC). Presented sample contains 7612 objects, including 5455 fundamental mode pulsators (RRab), 1655 first-overtone (RRc), 272 second-overtone (RRe) and 230 double-mode RR Lyr stars (RRd). Additionally we attach alist of several dozen other short-period pulsating variables. The catalog data include astrometry, periods, BVI photometry, amplitudes, and parameters of the Fourier decomposition of the I-band light curve of each object. We present density map of RR Lyr stars in the observed fields which shows that the variables are strongly concentrated toward the LMC center. The modal values of the period distribution for RRab, RRc and RRe stars are 0.573, 0.339 and 0.276 days, respectively. The period-luminosity diagrams for BVI magnitudes and for extinction insensitive index W_I are constructed. We provide the log P-I, log P-V and log P-W_I relations for RRab, RRc and RRe stars. The mean observed V-band magnitudes of RR Lyr stars in the LMC are 19.36 mag and 19.31 mag for ab and c types, respectively, while the extinction free values are 18.91 mag and 18.89 mag. We found a large number of RR Lyr stars pulsating in two modes closely spaced in the power spectrum. These stars are believed to exhibit non-radial pulsating modes. We discovered three stars which simultaneously reveal RR Lyr-type and eclipsing-type variability. If any of these objects were an eclipsing binary system containing RR Lyr star, then for the first time the direct determination of the mass of RR Lyr variable would be possible. We provide a list of six LMC star clusters which contain RR Lyr stars. The richest cluster, NGC 1835, hosts 84 RR Lyr variables. The period distribution of these stars suggests that NGC1835 shares features of Oosterhoff type I and type II groups. All presented data, including individual BVI observations and finding charts are available from the OGLE Internet archive.

Spectroscopic studies of Wolf-Rayet stars. III - The WC subclass

NASA Technical Reports Server (NTRS)

Torres, A. V.; Conti, P. S.; Massey, P.

1986-01-01

Wolf-Rayet (W-R) stars, which are the descendants of massive O-type stars, can be subdivided into three groups depending on their spectral appearance. These groups include the nitrogen class (WN), the carbon class (WC), and the oxygen class (WO). The present paper is concerned with the WC stars. The assignment of WC subtypes has been based on visual inspections of photographic plates. One of the aims of this study is related to the quantification of the visual estimates. The measured ratios of equivalent widths and the FWHM of the 4650 A line for Galactic and LMC stars are presented, and the reclassification of some stars is proposed on this basis. In particular, it is shown that the majority of the LMC WC stars should logically be classified WC4 instead of WC5. Comments on individual stars are provided, and terminal velocities are discussed. It is attempted to give a complete overview of the most important spectroscopic features of the WC stars in the optical region.

Hitomi Observations of the LMC SNR N132D: Fast and Asymmetric Iron-rich Ejecta

NASA Astrophysics Data System (ADS)

Miller, Eric D.; Hitomi Collaboration

2018-01-01

We present Hitomi Soft X-ray Spectrometer (SXS) observations of N132D, a young, ~2500 year-old, X-ray bright, O-rich core-collapse supernova remnant in the LMC. Despite a very short observation of only 3.7 ksec, the SXS easily detects the line complexes of He-like S K and Fe K with 16-17 counts in each. The Fe K feature is measured for the first time at high spectral resolution, and we find that the Fe K-emitting material is highly redshifted at ~1000 km/s compared to the local LMC ISM, indicating (1) that it arises from the SN ejecta, and (2) that this ejecta is highly asymmetric, since no corresponding blue-shifted component is found. The S K-emitting material has a velocity consistent with the local LMC ISM, and is likely swept-up ISM material. These results are consistent with spatial mapping of these emission lines with XMM-Newton and Chandra, which show the Fe K concentrated in the interior of the remnant and the S K tracing the outer shell. Most importantly, they highlight the power of high-spectral-resolution imaging observations, and demonstrate the new window that has been opened with Hitomi and will be greatly widened with future missions such as the X-ray Astronomy Recovery Mission (XARM) and Athena.

Relative Effect of Lecture Method Supplemented with Music and Computer Animation on Senior Secondary School Students' Retention in Electrochemistry

ERIC Educational Resources Information Center

Akpoghol, T. V.; Ezeudu, F. O.; Adzape, J. N.; Otor, E. E.

2016-01-01

The study investigated the effects of Lecture Method Supplemented with Music (LMM) and Computer Animation (LMC) on senior secondary school students' retention in electrochemistry in Makurdi metropolis. Three research questions and three hypotheses guided the study. The design of the study was quasi experimental, specifically the pre-test,…

Carrier concentration dependence of donor activation energy in n-type GaN epilayers grown on Si (1 1 1) by plasma-assisted MBE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Mahesh; Central Research Laboratory, Bharat Electronics, Bangalore 560 013; Bhat, Thirumaleshwara N.

Highlights: ► The n-type GaN layers were grown by plasma-assisted molecular beam epitaxy. ► The optical characteristics of a donor level in Si-doped GaN were studied. ► Activation energy of a Si-related donor was estimated from temperature dependent PL measurements. ► PL peak positions, FWHM of PL and activation energies are found to be proportional to the cube root of carrier density. ► The involvement of donor levels is supported by the temperature-dependent electron concentration measurements. -- Abstract: The n-type GaN layers were grown by plasma-assisted MBE and either intentionally doped with Si or unintentionally doped. The optical characteristics ofmore » a donor level in Si-doped, GaN were studied in terms of photoluminescence (PL) spectroscopy as a function of electron concentration. Temperature dependent PL measurements allowed us to estimate the activation energy of a Si-related donor from temperature-induced decay of PL intensity. PL peak positions, full width at half maximum of PL and activation energies are found to be proportional to the cube root of carrier density. The involvement of donor levels is supported by the temperature-dependent electron concentration measurements.« less

Structured star formation in the Magellanic inter-Cloud region

NASA Astrophysics Data System (ADS)

Mackey, A. D.; Koposov, S. E.; Da Costa, G. S.; Belokurov, V.; Erkal, D.; Fraternali, F.; McClure-Griffiths, N. M.; Fraser, M.

2017-12-01

We use a new contiguous imaging survey conducted using the Dark Energy Camera to investigate the distribution and properties of young stellar populations in the Magellanic inter-Cloud region. These young stars are strongly spatially clustered, forming a narrow chain of low-mass associations that trace the densest H I gas in the Magellanic Bridge and extend, in projection, from the SMC to the outer disc of the LMC. The associations in our survey footprint have ages ≲ 30 Myr, masses in the range ∼100-1200 M⊙ and very diffuse structures with half-light radii of up to ∼100 pc. The two most populous are strongly elliptical and aligned to ≈10°, with the axis joining the centres of the LMC and the SMC. These observations strongly suggest that the young inter-Cloud populations formed in situ, likely due to the compression of gas stripped during the most recent close LMC-SMC encounter. The associations lie at distances intermediate between the two Clouds, and we find no evidence for a substantial distance gradient across the imaged area. Finally, we identify a vast shell of young stars surrounding a central association, that is spatially coincident with a low column density bubble in the H I distribution. The properties of this structure are consistent with a scenario where stellar winds and supernova explosions from massive stars in the central cluster swept up the ambient gas into a shell, triggering a new burst of star formation. This is a prime location for studying stellar feedback in a relatively isolated environment.

Effectiveness of manual physical therapy to the cervical spine in the management of lateral epicondylalgia: a retrospective analysis.

PubMed

Cleland, Joshua A; Whitman, Julie M; Fritz, Julie M

2004-11-01

Retrospective ex-post facto design. To retrospectively review the management of patients with lateral epicondylalgia, and to compare self-reported outcomes to assess the potential benefit of manual physical therapy to the cervical spine. It has been postulated that dysfunction of the cervical spine may contribute to the symptoms associated with lateral epicondylalgia; however, the literature assessing the effectiveness of manual physical therapy to the cervicothoracic region in this patient population has been inconclusive. Documentation and analysis of outcomes of management strategies focusing on the cervical spine may lead to determining the most effective and efficient clinical practices. Of the 213 charts reviewed, 112 satisfied inclusion-exclusion criteria and were divided into 2 groups: those who received treatment solely directed at the elbow (local management [LM]), or those who received treatment directed at the elbow and cervical manual therapy (LM+C). Telephone follow-up interviews were used to determine the number of successful outcomes. Percentages of successful outcomes in each group were compared using chi-square analysis. An independent samples t test was used to compare the total number of visits per group. Sixty-one of the 112 patients were in the LM group, while 51 received LM+C. Seventy five percent of the patients available for follow-up in the LM group and 80% in the LM+C group reported a successful outcome. Patients in the LM group received a greater number of visits (mean, 9.7; SD, 2.4) than patients in the LM+C group (mean, 5.6; SD, 1.7; P<.01). The results of this retrospective review suggest that most patients had successful outcomes regardless of the inclusion of manual therapy interventions to the cervical spine. The LM+C group achieved the successful long-term outcome in significantly fewer visits.

Thermal Quenching of Photoluminescence in ZnO and GaN

NASA Astrophysics Data System (ADS)

Albarakati, Nahla Mubarak

Investigation of the thermal quenching of photoluminescence (PL) in semiconductors provides valuable information on identity and characteristics of point defects in these materials, which helps to better understand and improve the properties of semiconductor materials and devices. Abrupt and tunable thermal quenching (ATQ) of PL is a relatively new phenomenon with an unusual behavior of PL. This mechanism was able to explain what a traditional model failed to explain. Usually, in traditional model used to explain "normal" quenching, the slope of PL quenching in the Arrhenius plot determines the ionization energy of the defect causing the PL band. However, in abrupt quenching when the intensity of PL decreases by several orders of magnitude within a small range of temperature, the slope in the Arrhenius plot has no relation to the ionization energy of any defect. It is not known a priori if the thermal quenching of a particular PL band is normal or abrupt and tunable. Studying new cases of unusual thermal quenching, classifying and explaining them helps to predict new cases and understand deeper the ATQ mechanism of PL thermal quenching. Very few examples of abrupt and tunable quenching of PL in semiconductors can be found in literature. The abrupt and tunable thermal quenching, reported here for the first time for high-resistivity ZnO, provides an evidence to settle the dispute concerning the energy position of the Li Zn acceptor. In high-resistivity GaN samples, the common PL bands related to defects are the yellow luminescence (YL) band and a broad band in the blue spectral region (BL2). In this work, we report for the first time the observation of abrupt and tunable thermal quenching of the YL band in GaN. The activation energies for the YL and BL2 bands calculated through the new mechanism show agreement with the reported values. From this study we predict that the ATQ phenomenon is quite common for high-resistivity semiconductors.

Chronic pain coping styles in patients with herniated lumbar discs and coexisting spondylotic changes treated surgically: Considering clinical pain characteristics, degenerative changes, disability, mood disturbances, and beliefs about pain control.

PubMed

Misterska, Ewa; Jankowski, Roman; Głowacki, Maciej

2013-12-27

Pain catastrophizing, appraisals of pain control, styles of coping, and social support have been suggested to affect functioning in patients with low back pain. We investigated the relation of chronic pain coping strategies to psychological variables and clinical data, in patients treated surgically due to lumbar disc herniation and coexisting spondylotic changes. The average age of study participants (n=90) was 43.47 years (SD 10.21). Patients completed the Polish versions of the Chronic Pain Coping Inventory-42 (PL-CPCI-42), Beck Depression Inventory (BDI-PL), Coping Strategies Questionnaire (CSQ-PL), Beliefs about Pain Control Questionnaire (BPCQ-PL), and Roland-Morris Disability Questionnaire (RMQ-PL). In the PL-CPCI-42 results, resting, guarding and coping self-statements were frequently used as coping strategies (3.96 SD 1.97; 3.72 SD 1.72; 3.47 SD 2.02, respectively). In the CSQ-PL domains, catastrophizing and praying/hoping were frequently used as coping strategies (3.62 SD 1.19). The mean score obtained from the BDI-PL was 11.86 SD 7.23, and 12.70 SD 5.49 from the RMDQ-PL. BPCQ-PL results indicate that the highest score was in the subscale measuring beliefs that powerful others can control pain (4.36 SD 0.97). Exercise correlated significantly with beliefs about internal control of pain (rs=0.22). We identified associations between radiating pain and guarding (p=0.038) and between sports recreation and guarding (p=0.013) and task persistence (p=0.041). Back pain characteristics, depressive mood, disability, and beliefs about personal control of pain are related to chronic LBP coping styles. Most of the variables related to advancement of degenerative changes were not associated with coping efforts.

Determinants of Treatment Abandonment in Childhood Cancer: Results from a Global Survey.

PubMed

Friedrich, Paola; Lam, Catherine G; Kaur, Geetinder; Itriago, Elena; Ribeiro, Raul C; Arora, Ramandeep S

2016-01-01

Understanding and addressing treatment abandonment (TxA) is crucial for bridging the pediatric cancer survival gap between high-income (HIC) and low-and middle-income countries (LMC). In childhood cancer, TxA is defined as failure to start or complete curative cancer therapy and known to be a complex phenomenon. With rising interest on causes and consequences of TxA in LMC, this study aimed to establish the lay-of-the-land regarding determinants of TxA globally, perform and promote comparative research, and raise awareness on this subject. Physicians (medical oncologists, surgeons, and radiation therapists), nurses, social workers, and psychologists involved in care of children with cancer were approached through an online survey February-May 2012. Queries addressed social, economic, and treatment-related determinants of TxA. Free-text comments were collected. Descriptive and qualitative analyses were performed. Appraisal of overall frequency, burden, and predictors of TxA has been reported separately. 581 responses from 101 countries were obtained (contact rate = 26%, cooperation rate = 70%). Most respondents were physicians (86%), practicing pediatric hematology/oncology (86%) for >10 years (54%). Providers from LMC considered social/economic factors (families' low socioeconomic status, low education, and long travel time), as most influential in increasing risk of TxA. Treatment-related considerations such as preference for complementary and alternative medicine and concerns about treatment adverse effects and toxicity, were perceived to play an important role in both LMC and HIC. Perceived prognosis seemed to mediate the role of other determinants such as diagnosis and treatment phase on TxA risk. For example, high-risk of TxA was most frequently reported when prognosis clearly worsened (i.e. lack of response to therapy, relapse), or conversely when the patient appeared improved (i.e. induction completed, mass removed), as well as before aggressive/mutilating surgery. Provider responses allowed development of an expanded conceptual model of determinants of TxA; one which illustrates established and emerging individual, family, center, and context specific factors to be considered in order to tackle this problem. Emerging factors included vulnerability, family dynamics, perceptions, center capacity, public awareness, and governmental healthcare financing, among others. TxA is a complex and multifactorial phenomenon. With increased recognition of the role of TxA on global pediatric cancer outcomes, factors beyond social/economic status and beliefs have emerged. Our results provide insights regarding the role of established determinants of TxA in different geographical and economic contexts, allow probing of key determinants by deliberating their mechanisms, and allow building an expanded conceptual model of established and emerging determinants TxA.

On the impact of helium abundance on the Cepheid period-luminosity and Wesenheit relations and the distance ladder

NASA Astrophysics Data System (ADS)

Carini, R.; Brocato, E.; Raimondo, G.; Marconi, M.

2017-08-01

This work analyses the effect of the helium content on synthetic period-luminosity relations (PLRs) and period-Wesenheit relations (PWRs) of Cepheids and the systematic uncertainties on the derived distances that a hidden population of He-enhanced Cepheids may generate. We use new stellar and pulsation models to build a homogeneous and consistent framework to derive the Cepheid features. The Cepheid populations expected in synthetic colour-magnitude diagrams of young stellar systems (from 20 to 250 Myr) are computed in several photometric bands for Y = 0.25 and 0.35, at a fixed metallicity (Z = 0.008). The PLRs appear to be very similar in the two cases, with negligible effects (few per cent) on distances, while PWRs differ somewhat, with systematic uncertainties in deriving distances as high as ˜ 7 per cent at log P < 1.5. Statistical effects due to the number of variables used to determine the relations contribute to a distance systematic error of the order of few percent, with values decreasing from optical to near-infrared bands. The empirical PWRs derived from multiwavelength data sets for the Large Magellanic Cloud (LMC) is in a very good agreement with our theoretical PWRs obtained with a standard He content, supporting the evidence that LMC Cepheids do not show any He effect.

Differential uptake of salicylate in serum, cerebrospinal fluid, and perilymph.

PubMed

Jastreboff, P J; Hansen, R; Sasaki, P G; Sasaki, C T

1986-10-01

After intraperitoneal administration of salicylate in anesthetized rats and guinea pigs, we found that salicylate levels in perilymph (PL) are closely related to both drug levels in cerebrospinal fluid (CSF) and in serum, with higher levels systematically observed in PL than in CSF. Further analysis suggests that salicylate is not passively transported into PL across CSF but, rather, is transported from blood directly to PL. The time course of salicylate uptake in rats reveals maximum levels at 1 1/2 hours (serum) and two to four hours (CSF and PL). On the other hand, salicylate uptake into serum and CSF of guinea pigs exhibits a longer time course, with maximum levels reached at four hours (serum) and five hours (CSF). These data, not previously available, are basic to our understanding of salicylate-related auditory effects.

The X-ray eclipse of the LMC binary CAL 87

NASA Technical Reports Server (NTRS)

Schmidtke, P. C.; Mcgrath, T. K.; Cowley, A. P.; Frattare, L. M.

1993-01-01

ROSAT-PSPC observations of the LMC eclipsing binary CAL 87 show a short-duration, shallow X-ray eclipse which coincides in phase with the primary optical minimum. Characteristics of the eclipse suggest the X-ray emitting region is only partially occulted. Similarities with the eclipse of the accretion-disk corona in X 1822-37 are discussed. However, no temperature variation through eclipse is found for CAL 87. A revised orbital period, combining published data and recent optical photometry, is given.

ASTRONOMY: The Distance to the Large Magellanic Cloud.

PubMed

Cole, A A

2000-08-18

The Large Magellanic Cloud (LMC), a satellite of the Milky Way, is an important yardstick by which most intergalactic distances are measured. But as Cole explains in this Perspective, how far away the LMC is remains a matter of dispute, with far reaching implications in cosmology. But observations of Cepheids and of eclipsing binaries, two types of stars that allow absolute luminosity and thus absolute distances to be determined, are promising to resolve this important issue in the not too distant future.

Kinesiophobia in pre-operative patients with cervical discopathy and coexisting degenerative changes in relation to pain-related variables, psychological state and sports activity.

PubMed

Misterska, Ewa; Jankowski, Roman; Głowacki, Jakub; Shadi, Milud; Walczak, Michał; Głowacki, Maciej

2015-01-14

No research group has ever investigated the level of kinesiophobia in a well defined group of preoperative patients treated due to cervical discopathy and degenerative spine disease, confirmed by X-ray and magnetic resonance imaging (MRI) examinations. We aimed to investigate the degree of kinesiophobia and the differences in pain-related and psychosocial characteristics between patients with high and low levels of kinesiophobia, in relation to factors commonly associated with neck pain. Sixty-five consecutive patients with cervical discopathy and coexisting degenerative changes were assessed pre-surgically. The mean pain duration was 31.7 SD 34.0 months. Patients completed the Polish versions of the Tampa Scale for Kinesiophobia (TSK-PL) on 2 occasions, and the following once: Neck Disability Index (NDI-PL), State-Trait Anxiety Inventory (STAI-PL), Coping Strategies Questionnaire (CSQ-PL), and the Visual Analogue Scale (VAS-PL). A high level of kinesiophobia was indicated in 81.5% and 87.7% of patients in first and second completion, respectively. Patients with high and low kinesiophobia differ in regards to the recreation section of NDI-PL (p=0.012), gender (p=0.043), and sports activity (p=0.024). Correlations were identified between TSK-PL and marital status (p=0.023) and sports activity (p=0.024). Kinesiophobia levels are higher in patients with chronic cervical pain before surgical treatment. Fear of movement tends to be higher in women and among patients avoiding sports recreation before surgical treatment. Although sports activity and socio-demographic data are predictors of kinesiophobia, psychological, pain-related, and clinical data are not. These findings should be considered when planning rehabilitation after surgical treatment of cervical discopathy and coexisting degenerative changes.

A Cosmic Zoo in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

2010-06-01

Astronomers often turn their telescopes to the Large Magellanic Cloud (LMC), one of the closest galaxies to our own Milky Way, in their quest to understand the Universe. In this spectacular new image from the Wide Field Imager (WFI) at ESO's La Silla Observatory in Chile, a celestial menagerie of different objects and phenomena in part of the LMC is on display, ranging from vast globular clusters to the remains left by brilliant supernovae explosions. This fascinating observation provides data for a wide variety of research projects unravelling the life and death of stars and the evolution of galaxies. The Large Magellanic Cloud (LMC) is only about 160 000 light-years from our own Milky Way - very close on a cosmic scale. This proximity makes it a very important target as it can be studied in far more detail than more distant systems. The LMC lies in the constellation of Dorado (the Swordfish), deep in the southern sky and well placed for observations from ESO's observatories in Chile. It is one of the galaxies forming the Local Group surrounding the Milky Way [1]. Though enormous on a human scale, the LMC is less than one tenth the mass of our home galaxy and spans just 14 000 light-years compared to about 100 000 light-years for the Milky Way. Astronomers refer to it as an irregular dwarf galaxy [2]. Its irregularity, combined with its prominent central bar of stars suggests to astronomers that tidal interactions with the Milky Way and fellow Local Group galaxy, the Small Magellanic Cloud, could have distorted its shape from a classic barred spiral into its modern, more chaotic form. This image is a mosaic of four pictures from the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The image covers a region of sky more than four times as large as the full Moon. The huge field of view of this camera makes it possible to see a very wide range of objects in the LMC in a single picture, although only a small part of the entire galaxy can be included. Dozens of clusters of young stars can be seen as well as traces of glowing gas clouds. Huge numbers of faint stars fill the image from edge to edge and in the background, more galaxies, far beyond the LMC, are visible. Globular clusters are collections of hundreds of thousands to millions of stars bound by gravity into a roughly spherical shape just a few light-years across. Many clusters orbit the Milky Way and most are ancient, over ten billion years old, and composed mainly of old red stars. The LMC also has globular clusters and one is visible as the fuzzy white oval cluster of stars in the upper right part of the image. This is NGC 1978, an unusually massive globular cluster. Unlike most other globular clusters, NGC 1978 is believed to be just 3.5 billion years old. The presence of this kind of object in the LMC leads astronomers to think that the LMC has a more recent history of active star formation than our own Milky Way. As well as being a vigorous region of star birth, the LMC has also seen many spectacular stellar deaths in the form of brilliant supernova explosions. At the top right of the image, the remnant of one such supernova, a strangely shaped wispy cloud called DEM L 190, often also referred to as N 49, can be seen. This giant cloud of glowing gas is the brightest supernova remnant in the LMC, and is about 30 light-years across. At the centre, where the star once burned, now lies a magnetar, a neutron star with an extremely powerful magnetic field. It was only in 1979 that satellites orbiting Earth detected a powerful gamma-ray burst from this object, drawing attention to the extreme properties of this new class of stellar exotica created by supernova explosions. This part of the Large Magellanic Cloud is so packed with star clusters and other objects that astronomers can spend entire careers exploring it. With so much activity, it is easy to see why astronomers are so keen to study the strange creatures in this heavenly zoo. Notes [1] http://en.wikipedia.org/wiki/Local_Group [2] http://en.wikipedia.org/wiki/Galaxy_morphological_classification More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

Identification of two new HMXBs in the LMC: an ˜2013 s pulsar and a probable SFXT

NASA Astrophysics Data System (ADS)

Vasilopoulos, G.; Maitra, C.; Haberl, F.; Hatzidimitriou, D.; Petropoulou, M.

2018-03-01

We report on the X-ray and optical properties of two high-mass X-ray binary systems located in the Large Magellanic Cloud (LMC). Based on the obtained optical spectra, we classify the massive companion as a supergiant star in both systems. Timing analysis of the X-ray events collected by XMM-Newton revealed the presence of coherent pulsations (spin period ˜2013 s) for XMMU J053108.3-690923 and fast flaring behaviour for XMMU J053320.8-684122. The X-ray spectra of both systems can be modelled sufficiently well by an absorbed power law, yielding hard spectra and high intrinsic absorption from the environment of the systems. Due to their combined X-ray and optical properties, we classify both systems as SgXRBs: the 19th confirmed X-ray pulsar and a probable supergiant fast X-ray transient in the LMC, the second such candidate outside our Galaxy.

Network adaptation improves temporal representation of naturalistic stimuli in Drosophila eye: I dynamics.

PubMed

Zheng, Lei; Nikolaev, Anton; Wardill, Trevor J; O'Kane, Cahir J; de Polavieja, Gonzalo G; Juusola, Mikko

2009-01-01

Because of the limited processing capacity of eyes, retinal networks must adapt constantly to best present the ever changing visual world to the brain. However, we still know little about how adaptation in retinal networks shapes neural encoding of changing information. To study this question, we recorded voltage responses from photoreceptors (R1-R6) and their output neurons (LMCs) in the Drosophila eye to repeated patterns of contrast values, collected from natural scenes. By analyzing the continuous photoreceptor-to-LMC transformations of these graded-potential neurons, we show that the efficiency of coding is dynamically improved by adaptation. In particular, adaptation enhances both the frequency and amplitude distribution of LMC output by improving sensitivity to under-represented signals within seconds. Moreover, the signal-to-noise ratio of LMC output increases in the same time scale. We suggest that these coding properties can be used to study network adaptation using the genetic tools in Drosophila, as shown in a companion paper (Part II).

Massive star evolution and SN 1987A

NASA Technical Reports Server (NTRS)

Arnett, David

1991-01-01

The evolution of massive stars through hydrogen and helium burning is addressed. A set of stellar evolutionary sequences for mass/solar mass of 15, 20, and 25, and metallicity of 0.002, 0.005, 0.007, 0.010, and 0.20 are presented; semiconvection is restricted to operating slower than the local thermal time scale. Using these sequences, simple models of the massive star content of the LMC are found to agree moderately well with the new observational data of Fitzpatrick and Garmany (1990). LMC supergiants were detected only in their postmain-sequence phases, so that 5-10 times more massive stars are there but not identified as such. It is argued that SN 1987A exhibits the normal evolution of a single star of about 20 solar mases having LMC abundances. Despite the variety of envelope behavior, the structure of the core at collapse is rather similar for the stars of a given mass. Variations due to different rates of mass loss are likely to be larger than those due to composition.

Cúmulos jóvenes inmersos en campos de edad intermedia en la barra de la Nube Mayor de Magallanes

NASA Astrophysics Data System (ADS)

Piatti, A. E.; Geisler, D.; Bica, E.; Clariá, J. J.

We present Washington system photometry for 11 star clusters immersed in the northwest part of the Large Magellanic Cloud (LMC) bar. The fields are heavily populated by the intermediate-age component of the LMC bar. We succeeded in disentangling cluster colour-magnitude diagrams from those of the fields and in deriving reddening and ages for five clusters - SL 218, BRHT4b, NGC 1839, NGC 1838 and NGC 1863 - with the aid of recent Washington System theoretical isochrones. The resulting cluster ages range between 50 and 125 Myr. Despite their proximity, NGC 1836 and BRHT4b have very different ages. Thus the possibility for these two objects being a binary cluster is very unlikely, although a capture cannot be ruled out a priori. Our results suggest that for each intermediate-age cluster remaining in the LMC bar region, a number of robust young blue star clusters occurs in the same region (Piatti et al. 2003, MNRAS, 343, 851).

The Near-infrared Tip of the Red Giant Branch. II. An Absolute Calibration in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Hoyt, Taylor J.; Freedman, Wendy L.; Madore, Barry F.; Seibert, Mark; Beaton, Rachael L.; Hatt, Dylan; Jang, In Sung; Lee, Myung Gyoon; Monson, Andrew J.; Rich, Jeffrey A.

2018-05-01

We present a new empirical JHK absolute calibration of the tip of the red giant branch (TRGB) in the Large Magellanic Cloud (LMC). We use published data from the extensive Near-Infrared Synoptic Survey containing 3.5 million stars, 65,000 of which are red giants that fall within one magnitude of the TRGB. Adopting the TRGB slopes from a companion study of the isolated dwarf galaxy IC 1613, as well as an LMC distance modulus of μ 0 = 18.49 mag from (geometric) detached eclipsing binaries, we derive absolute JHK zero points for the near-infrared TRGB. For a comparison with measurements in the bar alone, we apply the calibrated JHK TRGB to a 500 deg2 area of the 2MASS survey. The TRGB reveals the 3D structure of the LMC with a tilt in the direction perpendicular to the major axis of the bar, which is in agreement with previous studies.

Spectrophotometry of Wolf-Rayet stars. I - Continuum energy distributions

NASA Technical Reports Server (NTRS)

Morris, Patrick W.; Brownsberger, Kenneth R.; Conti, Peter S.; Massey, Philip; Vacca, William D.

1993-01-01

All available low-resolution IUE spectra are assembled for Galactic, LMC, and SMC W-R stars and are merged with ground-based optical and NIR spectra in order to collate in a systematic fashion the shapes of these energy distributions over the wavelength range 0.1-1 micron. They can be consistently fitted by a power law of the form F(lambda) is approximately equal to lambda exp -alpha over the range 1500-9000 A to derive color excesses E(B-V) and spectral indices by removing the 2175-A interstellar absorption feature. The WN star color excesses derived are found to be in good agreement with those of Schmutz and Vacca (1991) and Koesterke et al. (1991). Significant heterogeneity in spectral index values was generally seen with any given subtype, but the groups consisting of the combined set of Galactic and LMC W-R stars, the separate WN and WC sequences, and the Galactic and LMC W-R stars all showed a striking and consistent Gaussian-like frequency distribution of values.

What drives the formation of massive stars and clusters?

NASA Astrophysics Data System (ADS)

Ochsendorf, Bram; Meixner, Margaret; Roman-Duval, Julia; Evans, Neal J., II; Rahman, Mubdi; Zinnecker, Hans; Nayak, Omnarayani; Bally, John; Jones, Olivia C.; Indebetouw, Remy

2018-01-01

Galaxy-wide surveys allow to study star formation in unprecedented ways. In this talk, I will discuss our analysis of the Large Magellanic Cloud (LMC) and the Milky Way, and illustrate how studying both the large and small scale structure of galaxies are critical in addressing the question: what drives the formation of massive stars and clusters?I will show that ‘turbulence-regulated’ star formation models do not reproduce massive star formation properties of GMCs in the LMC and Milky Way: this suggests that theory currently does not capture the full complexity of star formation on small scales. I will also report on the discovery of a massive star forming complex in the LMC, which in many ways manifests itself as an embedded twin of 30 Doradus: this may shed light on the formation of R136 and 'Super Star Clusters' in general. Finally, I will highlight what we can expect in the next years in the field of star formation with large-scale sky surveys, ALMA, and our JWST-GTO program.

Network Adaptation Improves Temporal Representation of Naturalistic Stimuli in Drosophila Eye: I Dynamics

PubMed Central

Wardill, Trevor J.; O'Kane, Cahir J.; de Polavieja, Gonzalo G.; Juusola, Mikko

2009-01-01

Because of the limited processing capacity of eyes, retinal networks must adapt constantly to best present the ever changing visual world to the brain. However, we still know little about how adaptation in retinal networks shapes neural encoding of changing information. To study this question, we recorded voltage responses from photoreceptors (R1–R6) and their output neurons (LMCs) in the Drosophila eye to repeated patterns of contrast values, collected from natural scenes. By analyzing the continuous photoreceptor-to-LMC transformations of these graded-potential neurons, we show that the efficiency of coding is dynamically improved by adaptation. In particular, adaptation enhances both the frequency and amplitude distribution of LMC output by improving sensitivity to under-represented signals within seconds. Moreover, the signal-to-noise ratio of LMC output increases in the same time scale. We suggest that these coding properties can be used to study network adaptation using the genetic tools in Drosophila, as shown in a companion paper (Part II). PMID:19180196

Spectral and Timing States in Black Hole Binaries

NASA Astrophysics Data System (ADS)

Wilms, J.

Results on the long term variability of galactic black hole candidates are reviewed. I mainly present the results of a > 2 year long campaign with RXTE to monitor the canonical soft state black hole candidates LMC X-1 and LMC X-3 using monthly observations. These observations are presented within the context of the RXTE-ASM long term quasi-periodic variability on timescales of about 150d. For LMC X-3, times of low ASM count rate are correlated with a significant hardening of the X-ray spectrum. The observation with the lowest flux during the whole monitoring campaign can be modeled with a simple γ=1.7 power law -- a hard state spectrum. Since these spectral hardenings occur on the 150 d timescale it is probable that they are associated with periodic changes in the accretion rate. Possible causes for this behavior are discussed, e.g. a wind driven limit-cycle or long-term variability of the donor star.

Investigating the low-mass slope and possible turnover in the LMC IMF

NASA Astrophysics Data System (ADS)

Gennaro, Mario

2014-10-01

We propose to derive the Initial Mass Function (IMF) of the field population of the Large Magellanic Cloud (LMC) down to 0.2 solar masses, probing the mass regime where the characteristic IMF turnover is observed in our Galaxy. The power of the HST, using the WFC3 IR channel, is necessary to obtain photometric mass estimates for the faint, cool, dwarf stars with masses below the expected IMF turnover point. Only by probing the IMF down to such masses, it will be possible to clearly distinguish between a bottom-heavy or bottom-light IMF in the LMC. Recent studies, using the deepest available observations for the Small Magellanic Cloud, cannot find clear evidence of a turnover in the IMF for this galaxy, suggesting a bottom-heavy IMF in contrast to the Milky Way. A similar study of the LMC is needed to confirm a possible dependence of the low-mass IMF with galactic environment. Studies of giant ellipticals have recently challenged the picture of a universal IMF, and suggest an enviromental dependence of the IMF, with the most massive galaxies having a larger fraction of low mass stars and no IMF turnover. A study of possible IMF variations from resolved stellar populations in nearby galaxies is of great importance in sheding light on this issue. Our simple approach, using direct evidence from basic star counts, is much less prone to systematic errors with respect to studies of more distant objects which have to rely on the observations of integrated properties.

Lean Manufacturing Auto Cluster at Chennai

NASA Astrophysics Data System (ADS)

Bhaskaran, E.

2012-10-01

Due the presence of lot of automotive Industry, Chennai is known as Detroit of India, that producing over 40 % of the Indian vehicle and components. Lean manufacturing concepts have been widely recognized as an important tool in improving the competitiveness of industries. This is a continuous process involving everyone, starting from management to the shop floor. Automotive Component Industries (ACIs) in Ambattur Industrial Estate, Chennai has formed special purpose vehicle (SPV) society namely Ambattur Industrial Estate Manufacturers Association (AIEMA) Technology Centre (ATC) lean manufacturing cluster (ATC-LMC) during July 2010 under lean manufacturing competitiveness scheme, that comes under National Manufacturing Competitiveness Programme of Government of India. The Tripartite Agreement is taken place between National Productivity Council, consultants and cluster (ATC-LMC). The objective is to conduct diagnostic study, study on training and application of various lean manufacturing techniques and auditing in ten ACIs. The methodology adopted is collection of primary data/details from ten ACIs. In the first phase, diagnostic study is done and the areas for improvement in each of the cluster member companies are identified. In the second phase, training programs and implementation is done on 5S and other areas. In the third phase auditing is done and found that the lean manufacturing techniques implementation in ATC-LMC is sustainable and successful in every cluster companies, which will not only enhance competitiveness but also decrease cost, time and increase productivity. The technical efficiency of LMC companies also increases significantly.

Antiphospholipid Antibodies and Recurrent Thrombotic Events: Persistence and Portfolio

PubMed Central

Amory, Colum F.; Levine, Steve R.; Brey, Robin L.; Gebregziabher, Mulugeta; Tuhrim, Stanley; Tilley, Barbara C.; Simpson, Ann-Catherin N.; Sacco, Ralph L.; Mohr, J.P.

2015-01-01

Background There are very limited prospective data on the significance of persistent of antiphospholipid antibodies (aPL) and recurrent thrombo-occlusive events (TOEs). We investigated the prognostic value of (1) two newer aPL assays, (2) an aPL portfolio, and (3) persistent aPL positivity following stroke. Methods 1,770 subjects from the APASS-WARSS study underwent further aPL testing for antibodies to phosphatidylserine (aPS) and β2-glycoprotein-I (anti-β2GPI) from stored sera. Follow-up aPL status was also tested in a subset of subjects. Primary analysis was based on time to any TOE (ischemic stroke, MI, TIA, DVT, PE, or systemic arterial occlusion)/death at 2 years. Cox proportional hazard analyses assessed whether aPL independently related to outcome. Results Persistent anti-β2GPI decreased the time to TOE/death after adjustment for potential confounders (HR=2.86, CI 1.21-6.76, p=0.017). When persistent anti-β2GPI was combined with another persistently positive aPL, time to TOE/death was also reduced (HR=3.79, CI 1.18-12.14, p=0.025). Neither persistent aCL, persistent aPS alone, nor a single positive anti-β2GPI or aPS was associated with decreased time to TOE/death. No single positive aPL, portfolio of baseline aPL, or any persistent aPL increased the rate of TOE/death. Conclusions Rates of TOE/death were not influenced by aPL results at baseline or follow-up. Persistent anti-β2GPI alone and with persistent second aPL were independently associated with decreased time to TOE/death. Persistent aPL, an aPL portfolio, and newer aPL in ischemic stroke patients are not helpful in predicting an increased rate of recurrent TOEs. PMID:26513489

Separation, purification, and α-glucosidase inhibition of polysaccharides from Coriolus versicolor LH1 mycelia.

PubMed

Hsu, Wen-kuang; Hsu, Tai-hao; Lin, Fang-yi; Cheng, Yuan-kai; Yang, John Po-wen

2013-01-30

Intracellular polysaccharides (iPs) were separated and purified from Coriolus versicolor LH1 mycelia and characterized for their α-glucosidase inhibitory properties. Three iP fractions (iPL-F5-2-1, iPL-F5-4-1, and iPL-F5-5-1) were extracted, separated, and purified from LH1 mycelia using microwave extraction technology, a DEAE-Sepharose CL-6B column, a Diaion HP20 macroporous adsorption column, and a Sephadex™ G-50 gel-permeation column. The principal constituents of iPL-F5-2-1, iPL-F5-4-1, and iPL-F5-5-1 were saponins and polyphenoic compound mixtures. The enzyme inhibition activity, IC(50) values, of these three fractions were 1.7, 1.8, and 0.8 mg/mL, respectively. The α-glucosidase inhibitory properties were related to the presence of α-(1,4) glycosidic linkages in the polysaccharide structure and the total relative percentage of d-glucose and d-galactose in the structure of polysaccharides, other than triterpenoids. Copyright © 2012 Elsevier Ltd. All rights reserved.

VizieR Online Data Catalog: DIB in VLT-FLAMES Tarantula Survey (van Loon+, 2013)

NASA Astrophysics Data System (ADS)

van Loon, J. T.; Bailey, M.; Tatton, B. L.; Maíz Apellániz, J.; Crowther, P. A.; de Koter, A.; Evans, C. J.; Henault-Brunet, V.; Howarth, I. D.; Richter, P.; Sana, H.; Simon-Diaz, S.; Taylor, W.; Walborn, N. R.

2012-11-01

Equivalent widths of the 4428, 5780, 5797 and 6614 Diffuse Interstellar Bands (DIBs) were measured for up to 800 OB-type stars in the Tarantula Nebula (30 Doradus, containing the massive compact star cluster R136) in the Large Magellanic Cloud (LMC). The Galactic foreground and LMC components were fitted simultaneously, with Lorentzians for the 4428 DIB and Gaussians for the other DIBs. All fits were inspected by eye, and a flag was reset to zero if the fit was rejected. (3 data files).

Bright X-ray transient in the LMC

NASA Astrophysics Data System (ADS)

Saxton, R.; Read, A. M.; Li, D. Y.

2018-01-01

We report a bright X-ray transient in the LMC from an XMM-Newton slew made on 5th January 2018. The source, XMMSL2 J053629.4-675940, had a soft X-ray (0.2-2 keV) count rate in the EPIC-pn detector, medium filter of 1.82+/-0.56 c/s, equivalent to a flux Fx=2.3+/-0.7E-12 ergs/s/cm2 for a nominal spectrum of a power-law of slope 2 absorbed by a column NH=3E20 cm^-2.

LMC: Logarithmantic Monte Carlo

NASA Astrophysics Data System (ADS)

Mantz, Adam B.

2017-06-01

LMC is a Markov Chain Monte Carlo engine in Python that implements adaptive Metropolis-Hastings and slice sampling, as well as the affine-invariant method of Goodman & Weare, in a flexible framework. It can be used for simple problems, but the main use case is problems where expensive likelihood evaluations are provided by less flexible third-party software, which benefit from parallelization across many nodes at the sampling level. The parallel/adaptive methods use communication through MPI, or alternatively by writing/reading files, and mostly follow the approaches pioneered by CosmoMC (ascl:1106.025).

Statistical manifestation of quantum correlations via disequilibrium

NASA Astrophysics Data System (ADS)

Pennini, F.; Plastino, A.

2017-12-01

The statistical notion of disequilibrium (D) was introduced by López-Ruiz, Mancini, and Calbet (LMC) (1995) [1] more than 20 years ago. D measures the amount of ;correlational structure; of a system. We wish to use D to analyze one of the simplest types of quantum correlations, those present in gaseous systems due to symmetry considerations. To this end we extend the LMC formalism to the grand canonical environment and show that D displays distinctive behaviors for simple gases, that allow for interesting insights into their structural properties.

VizieR Online Data Catalog: Synthetic JWST/MIRI fluxes and magnitudes (Jones+, 2017)

NASA Astrophysics Data System (ADS)

Jones, O. C.; Meixner, M.; Justtanont, K.; Glasse, A.

2018-01-01

In order to predict fluxes and colors through the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) filters, we have made use of Spitzer-IRS spectra, from the SAGE-Spec legacy survey of the LMC (Kemper+ 2010, J/PASP/122/683). The IRS spectra cover a wavelength range from 5.3 to 38um with spectral resolutions, R~60-600. For all sources in the LMC, we adopt a distance modulus of 18.49+/-0.05. See section 2 for further explanations. (2 data files).

The mass of the black hole in the X-ray binary LMC X-1

NASA Astrophysics Data System (ADS)

Abubekerov, M. K.; Antokhina, E. A.; Gostev, N. Yu.; Cherepashchuk, A. M.; Shimansky, V. V.

2016-12-01

A dynamical estimate of the mass of the black hole in the LMC X-1 binary system is obtained in the framework of a Roche model for the optical star, based on fitting of the He I 4471 Å and He II 4200 Å absorption lines assuming LTE. The mass of the black hole derived from the radial-velocity curve for the He II 4200 Å line is m x = 10.55 M ⊙, close to the value found earlier based on a model with two point bodies [1].

The origin and location of the 5 March 1979 gamma-ray burst

NASA Technical Reports Server (NTRS)

Kazanas, Demosthenes

1988-01-01

Evidence and arguments concerning the origin and location of the gamma-ray burst (GRB) of March 5, 1979 are reviewed. This GRB has been positionally identified with the SNR 49 in the LMC. Such an association would fix the GRB's distance at 55 kpc, and the observed flux from the GRB would require prodigious energy and luminosity, casting doubt on the GRB's distance and its association with the LMC. Some Kosmos 856 observations which may provide more direct evidence on the energy released are discussed.

Comparison of long-term outcome between anti-Jo1- and anti-PL7/PL12 positive patients with antisynthetase syndrome.

PubMed

Marie, I; Josse, S; Decaux, O; Dominique, S; Diot, E; Landron, C; Roblot, P; Jouneau, S; Hatron, P Y; Tiev, K P; Vittecoq, O; Noel, D; Mouthon, L; Menard, J-F; Jouen, F

2012-08-01

The aims of the present study were to: compare the characteristics between antisynthetase syndrome (ASS) patients with anti-Jo1 antibody and those with anti-PL7/PL12 antibody. The medical records of 95 consecutive patients with ASS were reviewed. Seventy-five of these patients had anti-Jo1 antibody; the other patients had anti-PL7 (n=15) or anti-PL12 (n=5) antibody. At ASS diagnosis, the prevalence of myalgia (p=0.007) and muscle weakness (p=0.02) was significantly lower in the group of anti-PL7/PL12-positive patients than in those with anti-Jo1 antibody; median value of CK (p=0.00003) was also lower in anti-PL7/PL12 patients. Anti-Jo1 positive patients developed more rarely myositis resolution (21.3% vs. 46.2%); in addition, the overall recurrence rate of myositis was higher in anti-Jo1 positive patients than in patients with anti-PL7/PL12 antibody (65.9% vs. 19.4%). Anti-Jo1-positive patients, compared with those with anti-PL7/PL12 antibody, more often experienced: joint involvement (63.3%vs. 40%) and cancer (13.3% vs. 5%). By contrast, anti-PL7/PL12 positive patients, compared with those with anti-Jo1 antibody, more commonly exhibited: ILD (90% vs. 68%); in anti-PL7/PL12 positive patients, ILD was more often symptomatic at diagnosis, and led more rarely to resolution of lung manifestations (5.6% vs. 29.4%). Finally, the group of anti-PL7/PL12 positive patients more commonly experienced gastrointestinal manifestations related to ASS (p=0.02). Taken together, although anti-Jo1 positive patients with ASS share some features with those with anti-PL7/PL12 antibody, they exhibit many differences regarding clinical phenotype and long-term outcome. Our study underscores that the presence of anti-Jo1 antibody results in more severe myositis, joint impairment and increased risk of cancer. On the other hand, the presence of anti-PL7/PL12 antibody is markedly associated with: early and severe ILD, and gastrointestinal complications. Thus, our study interestingly indicates that the finding for anti-Jo1 and anti-PL7/PL12 antibodies impacts both the long-term outcome and prognosis of patients with ASS. Copyright © 2012 Elsevier B.V. All rights reserved.

Placental growth factor (PlGF) is a surrogate marker in preeclamptic hypertension.

PubMed

Teixeira, Patrícia Gonçalves; Cabral, Antônio Carlos Vieira; Andrade, Silvia Passos; Reis, Zilma Silveira Nogueira; da Cruz, Lívia Pieroni Barroso; Pereira, Jacqueline Braga; Martins, Breno Oliveira de Barcelos; Rezende, Cezar Alencar de Lima

2008-01-01

To evaluate plasma levels of angiogenic factors and their association with preeclampsia. Twenty-three women with preeclampsia and nine normotensive pregnant women from the Maternity of Hospital das Clínicas of Belo Horizonte/MG-Brazil were assessed by National High Blood Pressure Education Program Working Group Creteria (NHBPEPWG). The plasma levels of vascular endothelial growth factor (VEGF) and Placental growth factor (PlGF) were determined by ELISA assay. Plasma concentration of PlGF was 12-fold lower in preeclampsia versus non preeclampsia pregnancies. An inverse correlation was observed between PlGF plasma levels and mean arterial pressure (MAP); a decrease in 1pg/mL of PlGF resulted in 6.18 mm Hg increase in MAP. These results indicate that PlGF is related to MAP in pregnant women.

A Semi-analytical Model for Wind-fed Black Hole High-mass X-Ray Binaries: State Transition Triggered by Magnetic Fields from the Companion Star

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yaji, Kentaro; Yamada, Shinya; Masai, Kuniaki

We propose a mechanism of state transition in wind-fed black hole (BH) binaries (high-mass X-ray binaries) such as Cyg X-1 and LMC X-1. Modeling a line-driven stellar wind from the companion by two-dimensional hydrodynamical calculations, we investigate the processes of wind capture by, and accretion onto, the BH. We assume that the wind acceleration is terminated at the He ii ionization front because ions responsible for line-driven acceleration are ionized within the front, i.e., the He iii region. It is found that the mass accretion rate inferred from the luminosity is remarkably smaller than the capture rate. Considering the difference,more » we construct a model for the state transition based on the accretion flow being controlled by magnetorotational instability. The outer flow is torus-like, and plays an important role to trigger the transition. The model can explain why state transition does occur in Cyg X-1, while not in LMC X-1. Cyg X-1 exhibits a relatively low luminosity, and then the He ii ionization front is located and can move between the companion and BH, depending on its ionizing photon flux. On the other hand, LMC X-1 exhibits too high luminosity for the front to move considerably; the front is too close to the companion atmosphere. The model also predicts that each state of high-soft or low-hard would last fairly long because the luminosity depends weakly on the wind velocity. In the context of the model, the state transition is triggered by a fluctuation of the magnetic field when its amplitude becomes comparable to the field strength in the torus-like outer flow.« less

The stellar mass, star formation rate and dark matter halo properties of LAEs at z ˜ 2

NASA Astrophysics Data System (ADS)

Kusakabe, Haruka; Shimasaku, Kazuhiro; Ouchi, Masami; Nakajima, Kimihiko; Goto, Ryosuke; Hashimoto, Takuya; Konno, Akira; Harikane, Yuichi; Silverman, John D.; Capak, Peter L.

2018-01-01

We present average stellar population properties and dark matter halo masses of z ˜ 2 Lyα emitters (LAEs) from spectral energy distribution fitting and clustering analysis, respectively, using ≃ 1250 objects (NB387≤25.5) in four separate fields of ≃ 1 deg2 in total. With an average stellar mass of 10.2 ± 1.8 × 108 M⊙ and star formation rate of 3.4 ± 0.4 M⊙ yr-1, the LAEs lie on an extrapolation of the star-formation main sequence (MS) to low stellar mass. Their effective dark matter halo mass is estimated to be 4.0_{-2.9}^{+5.1} × 10^{10}{ }M_{⊙} with an effective bias of 1.22^{+0.16}_{-0.18}, which is lower than that of z ˜ 2 LAEs (1.8 ± 0.3) obtained by a previous study based on a three times smaller survey area, with a probability of 96%. However, the difference in the bias values can be explained if cosmic variance is taken into account. If such a low halo mass implies a low H I gas mass, this result appears to be consistent with the observations of a high Lyα escape fraction. With the low halo masses and ongoing star formation, our LAEs have a relatively high stellar-to-halo mass ratio (SHMR) and a high efficiency of converting baryons into stars. The extended Press-Schechter formalism predicts that at z = 0 our LAEs are typically embedded in halos with masses similar to that of the Large Magellanic Cloud (LMC); they will also have similar SHMRs to the LMC, if their star formation rates are largely suppressed after z ˜ 2 as some previous studies have reported for the LMC itself.

DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. I. DUST PROPERTIES AND INSIGHTS INTO THE ORIGIN OF THE SUBMILLIMETER EXCESS EMISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, Karl D.; Roman-Duval, Julia; Meixner, Margaret

The dust properties in the Large and Small Magellanic clouds (LMC/SMC) are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 μm. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a power-law emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models, we investigate the origin of the submillimeter excess, defined as the submillimeter emission above that expected from SMBB models fit to observations <200more » μm. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 μm submillimeter excesses of 27% and 43% for the LMC and SMC, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our fitting results show that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submillimeter excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 ± 1.7) × 10{sup 5} and (8.3 ± 2.1) × 10{sup 4} M {sub ☉} for the LMC and SMC, respectively. We find significant correlations between the submillimeter excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.« less

Chemoport with a non-collapsible chamber as a replacement for an Ommaya reservoir in the treatment of leptomeningeal carcinomatosis.

PubMed

Gwak, Ho-Shin; Lee, Chang-Hyun; Yang, Hee Seok; Joo, Jungnam; Shin, Sang Hoon; Yoo, Heon; Lee, Jin Soo; Lee, Seung Hoon

2011-10-01

The Ommaya reservoir for intraventricular chemotherapy of leptomeningeal carcinomatosis (LMC) patients has been reported to have some complications. We introduced a Chemoport reservoir, with a solid non-collapsible, high-profile chamber as a the replacement for the Ommaya reservoir in LMC patients. To evaluate the usefulness of Chemoport as an alternative to Ommaya for the intraventricular chemotherapy of LMC. The medical records of 155 patients (89 Ommaya and 66 Chemoport) who underwent intraventricular chemotherapy via a subgaleal reservoir were reviewed. Chemoport was secured with engraving of skull. Reservoir malfunction, including one intracranial hemorrhage (ICH) under the burr hole occurred, in six patients. During the course of therapy, cerebrospinal fluid (CSF) infection was diagnosed in 19 patients and intraventricular hemorrhage with ICH was evident in three patients of the Ommaya group. Incidence of the above-mentioned complications showed no difference between the two groups. CSF leakage under a galeal flap or through a wound edge occurred more frequently in the Ommaya group (12 patients) than in the Chemoport group (two patients) and the difference was statistically significant (p = 0.03). One-hundred and four patients showed increased intracranial pressure (ICP) and 74 of them received additional CSF drainage to control increased ICP by either intermittent CSF drainage in both groups or continuous extraventricular drainage (EVD) of CSF using designated hooked needle only in the Chemoport group. Among the factors related to the control ICP, the number of chemotherapies, type of reservoir in favor of Chemoport, and EVD showed significantly improved control of ICP (p < 0.05). Chemoport, as a reservoir for intraventricular chemotherapy, has superior ICP control at an equal or lower rate of complications compared with the Ommaya reservoir.

Indian Society for Apheresis and apheresis tourism in India--is there a future?

PubMed

Srivastava, R

2006-04-01

Apheresis has now become an internationally popular mode of treatment for multiple immune complex disorders. However, the treatment remains quite expensive in Western Europe and the US. Apheresis tourism is a part of medical tourism or medical tourism specially related to therapeutic apheresis (TA) treatment in a foreign country on a cost effective basis. In the last couple of years, 'Medical Tourism' has become an upcoming and growing enterprise in India. The Indian Society for Apheresis (ISA) has taken a plunge at the opportune time and is trying to promote apheresis tourism in India. ISA is a member of various international apheresis organizations globally including the World Apheresis Association (WAA), the International Society for Apheresis (ISFA), the International Society for Artificial Organs (ISAO) and an associate of other national apheresis societies. The Indian Society for Apheresis (ISA) and the Ludhiana MediCiti (LMC) at Ludhiana Punjab are taking a big step in this direction. The therapeutic apheresis (TA) center at LMC is being set up as a Therapeutic Apheresis Institute and Research Center of excellence. The potential future impacts on the apheresis scenario are summarized.

Modeling transiting circumstellar disks: characterizing the newly discovered eclipsing disk system OGLE LMC-ECL-11893

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Erin L.; Mamajek, Eric E.; Pecaut, Mark J.

2014-12-10

We investigate the nature of the unusual eclipsing star OGLE LMC-ECL-11893 (OGLE J05172127-6900558) in the Large Magellanic Cloud recently reported by Dong et al. The eclipse period for this star is 468 days, and the eclipses exhibit a minimum of ∼1.4 mag, preceded by a plateau of ∼0.8 mag. Spectra and optical/IR photometry are consistent with the eclipsed star being a lightly reddened B9III star of inferred age ∼150 Myr and mass ∼4 M {sub ☉}. The disk appears to have an outer radius of ∼0.2 AU with predicted temperatures of ∼1100-1400 K. We model the eclipses as being duemore » to either a transiting geometrically thin dust disk or gaseous accretion disk around a secondary object; the debris disk produces a better fit. We speculate on the origin of such a dense circumstellar dust disk structure orbiting a relatively old low-mass companion, and on the similarities of this system to the previously discovered EE Cep.« less

Structural changes in the hot Algol OGLE-LMC-DPV-097 and its disc related to its long cycle

NASA Astrophysics Data System (ADS)

Garcés L, J.; Mennickent, R. E.; Djurašević, G.; Poleski, R.; Soszyński, I.

2018-06-01

Double Periodic Variables (DPVs) are hot Algols showing a long photometric cycle of uncertain origin. We report the discovery of changes in the orbital light curve of OGLE-LMC-DPV-097 which depend on the phase of its long photometric cycle. During the ascending branch of the long cycle the brightness at the first quadrature is larger than during the second quadrature, during the maximum of the long cycle the brightness is basically the same at both quadratures, during the descending branch the brightness at the second quadrature is larger than during the first quadrature, and during the minimum of the long cycle the secondary minimum disappears. We model the light curve at different phases of the long cycle and find that the data are consistent with changes in the properties of the accretion disc and two disc spots. The disc's size and temperature change with the long-cycle period. We find a smaller and hotter disc at minimum, and larger and cooler disc at maximum. The spot temperatures, locations, and angular sizes also show variability during the long cycle.

Large Magellanic Cloud Planetary Nebula Morphology: Probing Stellar Populations and Evolution.

PubMed

Stanghellini; Shaw; Balick; Blades

2000-05-10

Planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) offer the unique opportunity to study both the population and evolution of low- and intermediate-mass stars, by means of the morphological type of the nebula. Using observations from our LMC PN morphological survey, and including images available in the Hubble Space Telescope Data Archive and published chemical abundances, we find that asymmetry in PNe is strongly correlated with a younger stellar population, as indicated by the abundance of elements that are unaltered by stellar evolution (Ne, Ar, and S). While similar results have been obtained for Galactic PNe, this is the first demonstration of the relationship for extragalactic PNe. We also examine the relation between morphology and abundance of the products of stellar evolution. We found that asymmetric PNe have higher nitrogen and lower carbon abundances than symmetric PNe. Our two main results are broadly consistent with the predictions of stellar evolution if the progenitors of asymmetric PNe have on average larger masses than the progenitors of symmetric PNe. The results bear on the question of formation mechanisms for asymmetric PNe-specifically, that the genesis of PNe structure should relate strongly to the population type, and by inference the mass, of the progenitor star and less strongly on whether the central star is a member of a close binary system.

Massive runaway stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Gvaramadze, V. V.; Kroupa, P.; Pflamm-Altenburg, J.

2010-09-01

The origin of massive field stars in the Large Magellanic Cloud (LMC) has long been an enigma. The recent measurements of large offsets (˜ 100 km s-1) between the heliocentric radial velocities of some very massive (O2-type) field stars and the systemic LMC velocity provides a possible explanation of this enigma and suggests that the field stars are runaway stars ejected from their birthplaces at the very beginning of their parent cluster's dynamical evolution. A straightforward way to prove this explanation is to measure the proper motions of the field stars and to show that they are moving away from one of the nearby star clusters or OB associations. This approach is, however, complicated by the long distance to the LMC, which makes accurate proper motion measurements difficult. We used an alternative approach for solving the problem (first applied for Galactic field stars), based on the search for bow shocks produced by runaway stars. The geometry of detected bow shocks would allow us to infer the direction of stellar motion, thereby determining their possible parent clusters. In this paper we present the results of a search for bow shocks around six massive field stars that have been proposed as candidate runaway stars. Using archival Spitzer Space Telescope data, we found a bow shock associated with one of our programme stars, the O2 V((f*)) star BI 237, which is the first-ever detection of bow shocks in the LMC. Orientation of the bow shock suggests that BI 237 was ejected from the OB association LH 82 (located at ≃ 120 pc in projection from the star). A by-product of our search is the detection of bow shocks generated by four OB stars in the field of the LMC and an arc-like structure attached to the candidate luminous blue variable R81 (HD 269128). The geometry of two of these bow shocks is consistent with the possibility that their associated stars were ejected from the 30 Doradus star-forming complex. We discuss implications of our findings for the problem of the origin of runaway stars and the early dynamical evolution of star clusters.

Two serendipitous low-mass LMC clusters discovered with HST1

NASA Astrophysics Data System (ADS)

Santiago, Basilio X.; Elson, Rebecca A. W.; Sigurdsson, Steinn; Gilmore, Gerard F.

1998-04-01

We present V and I photometry of two open clusters in the LMC down to V~26. The clusters were imaged with the Wide Field and Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope (HST), as part of the Medium Deep Survey Key Project. Both are low-luminosity (M_V~-3.5), low-mass (M~10^3 Msolar) systems. The chance discovery of these two clusters in two parallel WFPC2 fields suggests a significant incompleteness in the LMC cluster census near the bar. One of the clusters is roughly elliptical and compact, with a steep light profile, a central surface brightness mu_V(0)~20.2 mag arcsec^-2, a half-light radius r_hl~0.9 pc (total visual major diameter D~3 pc) and an estimated mass M~1500 Msolar. From the colour-magnitude diagram and isochrone fits we estimate its age as tau~(2-5)x10^8 yr. Its mass function has a fitted slope of Gamma=Deltalogphi(M)/DeltalogM=-1.8+/-0.7 in the range probed (0.9<~M/Msolar<~4.5). The other cluster is more irregular and sparse, having shallower density and surface brightness profiles. We obtain Gamma=-1.2+/-0.4, and estimate its mass as M~400 Msolar. A derived upper limit for its age is tau<~5x10^8 yr. Both clusters have mass functions with slopes similar to that of R136, a massive LMC cluster, for which HST results indicate Gamma~-1.2. They also seem to be relaxed in their cores and well contained in their tidal radii.

Clouds, Streams and Bridges. Redrawing the blueprint of the Magellanic System with Gaia DR1

NASA Astrophysics Data System (ADS)

Belokurov, Vasily; Erkal, Denis; Deason, Alis J.; Koposov, Sergey E.; De Angeli, Francesca; Evans, Dafydd Wyn; Fraternali, Filippo; Mackey, Dougal

2017-04-01

We present the discovery of stellar tidal tails around the Large and the Small Magellanic Clouds (LMC and SMC, respectively) in the Gaia DR1 data. In between the Clouds, their tidal arms are stretched towards each other to form an almost continuous stellar bridge. Our analysis relies on the exquisite quality of the Gaia's photometric catalogue to build detailed star-count maps of the Clouds. We demonstrate that the Gaia DR1 data can be used to detect variable stars across the whole sky, and, in particular, RR Lyrae stars in and around the LMC and the SMC. Additionally, we use a combination of Gaia and GALEX to follow the distribution of Young Main Sequence stars in the Magellanic System. Viewed by Gaia, the Clouds show unmistakable signs of interaction. Around the LMC, clumps of RR Lyrae are observable as far as ˜20°, in agreement with the most recent map of Mira-like stars reported in Deason et al. The SMC's outer stellar density contours show a characteristic S-shape, symptomatic of the onset of tidal stripping. Beyond several degrees from the centre of the dwarf, the Gaia RR Lyrae stars trace the Cloud's trailing arm, extending towards the LMC. This stellar tidal tail mapped with RR Lyrae is not aligned with the gaseous Magellanic Bridge, and is shifted by some ˜5° from the Young Main Sequence bridge. We use the offset between the bridges to put constraints on the density of the hot gaseous corona of the Milky Way.

GUSTO: Gal/Xgal U/LDB Spectroscopic-Stratospheric TeraHertz Observatory

NASA Astrophysics Data System (ADS)

Kidd Walker, Christopher; Kulesa, Craig; Goldsmith, Paul; Groppi, Christopher; Helmich, Frank; Hollenbach, David; Kawamura, Jonathan; Langer, William; Melnick, Gary; Neufeld, David; Pineda, Jorge; Stacey, Gordon; Stark, Antony; Tielens, Alexander; Wolfire, Mark; Yorke, Harold; Young, Erick

2018-01-01

GUSTO is a recently selected NASA Explorer mission that will map in unprecedented detail the structure, dynamics, energy balance, and evolution of the interstellar medium within the Milky Way and Large Magellanic Cloud. GUSTO is a balloon-borne, 0.85-m on-axis telescope that will observe in three important interstellar lines: [CII], [OI], and [NII] at 158, 63, and 205 microns, respectively. With its 60" angular resolution, high-velocity resolution, and efficient “On-The-Fly” mapping strategy, GUSTO will address key unanswered questions about the stellar life cycle and provide new insights into the birth and evolution of stars and galaxies. From its Ultra-Long-Duration Balloon (ULDB) platform at an altitude of 33 km, GUSTO will survey ~100 deg2 of the Milky Way and 24 deg2 of the LMC at 60" angular resolution using three 8-pixel heterodyne array receivers. The GUSTO receivers provide sub-km/s velocity resolution and bandwidths sufficiently wide to track all clouds orbiting in the Milky Way and LMC. GUSTO will detect and locate in three dimensions every important interstellar cloud (AV > 0.5–1) in the surveyed regions. The baseline mission of 100 days can be completed in one ULDB Antarctic balloon flight, and an extended mission of up to 169 days is possible. GUSTO’s observing campaign comprises three distinct surveys: GPS: A Galactic Plane Survey (42 days); LMCS: An LMC Survey (36 days); TDS: Targeted Deep Surveys of selected regions in the Galaxy and LMC (18 days). In our presentation we will discuss both the science goals of GUSTO and the mission implementation.

Survivability of immunoassay reagents exposed to the space radiation environment on board the ESA BIOPAN-6 platform as a prelude to performing immunoassays on Mars.

PubMed

Derveni, Mariliza; Allen, Marjorie; Sawakuchi, Gabriel O; Yukihara, Eduardo G; Richter, Lutz; Sims, Mark R; Cullen, David C

2013-01-01

The Life Marker Chip (LMC) instrument is an immunoassay-based sensor that will attempt to detect signatures of life in the subsurface of Mars. The molecular reagents at the core of the LMC have no heritage of interplanetary mission use; therefore, the design of such an instrument must take into account a number of risk factors, including the radiation environment that will be encountered during a mission to Mars. To study the effects of space radiation on immunoassay reagents, primarily antibodies, a space study was performed on the European Space Agency's 2007 BIOPAN-6 low-Earth orbit (LEO) space exposure platform to complement a set of ground-based radiation studies. Two antibodies were used in the study, which were lyophilized and packaged in the intended LMC format and loaded into a custom-made sample holder unit that was mounted on the BIOPAN-6 platform. The BIOPAN mission went into LEO for 12 days, after which all samples were recovered and the antibody binding performance was measured via enzyme-linked immunosorbent assays (ELISA). The factors expected to affect antibody performance were the physical conditions of a space mission and the exposure to space conditions, primarily the radiation environment in LEO. Both antibodies survived inactivation by these factors, as concluded from the comparison between the flight samples and a number of shipping and storage controls. This work, in combination with the ground-based radiation tests on representative LMC antibodies, has helped to reduce the risk of using antibodies in a planetary exploration mission context.

The ultraviolet view of the Magellanic Clouds from GALEX: A first look at the LMC source catalog

NASA Astrophysics Data System (ADS)

Simons, Raymond; Thilker, David; Bianchi, Luciana; Wyder, Ted

2014-03-01

The Galaxy Evolution Exporer (GALEX) has performed unprecedented imaging surveys of the Magellanic Clouds (MC) and their surrounding areas including the Magellanic Bridge (MB) in near-UV (NUV, 1771-2831 Å) and far-UV (FUV, 1344-1786 Å) bands at 5″ resolution. Substantially more area was covered in the NUV than FUV, particularly in the bright central regions, because of the GALEX FUV detector failure. The 5σ depth of the NUV imaging varies between 20.8 and 22.7 (ABmag). Such imaging provides the first sensitive view of the entire content of hot stars in the Magellanic System, revealing the presence of young populations even in sites with extremely low star-formation rate surface density like the MB, owing to high sensitivity of the UV data to hot stars and the dark sky at these wavelengths. The density of UV sources is quite high in many areas of the LMC and SMC. Crowding limits the quality of source detection and photometry from the standard mission pipeline processing. We performed custom-photometry of the GALEX data in the MC survey region (<15° from the LMC, <10° from the SMC). After merging multiple detections of sources in overlapping images, the resulting catalog we have produced for the LMC contains nearly six million unique NUV point sources within 15° and is briefly presented herein. This paper provides a first look at the GALEX MC survey and highlights some of the science investigations that the entire catalog and imaging dataset will make possible.

A 2.4% DETERMINATION OF THE LOCAL VALUE OF THE HUBBLE CONSTANT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riess, Adam G.; Scolnic, Dan; Jones, David O.

We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample of reliable SNe Ia having a Cepheid-calibrated distance to a total of 19; these in turn leverage the magnitude-redshift relation based on ∼300 SNe Ia at z < 0.15. All 19 hosts as well as the megamaser system NGC 4258more » have been observed with WFC3 in the optical and NIR, thus nullifying cross-instrument zeropoint errors in the relative distance estimates from Cepheids. Other noteworthy improvements include a 33% reduction in the systematic uncertainty in the maser distance to NGC 4258, a larger sample of Cepheids in the Large Magellanic Cloud (LMC), a more robust distance to the LMC based on late-type detached eclipsing binaries (DEBs), HST observations of Cepheids in M31, and new HST -based trigonometric parallaxes for Milky Way (MW) Cepheids. We consider four geometric distance calibrations of Cepheids: (i) megamasers in NGC 4258, (ii) 8 DEBs in the LMC, (iii) 15 MW Cepheids with parallaxes measured with HST /FGS, HST /WFC3 spatial scanning and/or Hipparcos , and (iv) 2 DEBs in M31. The Hubble constant from each is 72.25 ± 2.51, 72.04 ± 2.67, 76.18 ± 2.37, and 74.50 ± 3.27 km s{sup 1} Mpc{sup 1}, respectively. Our best estimate of H {sub 0} = 73.24 ± 1.74 km s{sup 1} Mpc{sup 1} combines the anchors NGC 4258, MW, and LMC, yielding a 2.4% determination (all quoted uncertainties include fully propagated statistical and systematic components). This value is 3.4 σ higher than 66.93 ± 0.62 km s{sup 1} Mpc{sup 1} predicted by ΛCDM with 3 neutrino flavors having a mass of 0.06 eV and the new Planck data, but the discrepancy reduces to 2.1 σ relative to the prediction of 69.3 ± 0.7 km s{sup 1} Mpc{sup 1} based on the comparably precise combination of WMAP +ACT+SPT+BAO observations, suggesting that systematic uncertainties in CMB radiation measurements may play a role in the tension. If we take the conflict between Planck high-redshift measurements and our local determination of H {sub 0} at face value, one plausible explanation could involve an additional source of dark radiation in the early universe in the range of Δ N {sub eff} ≈ 0.4–1. We anticipate further significant improvements in H {sub 0} from upcoming parallax measurements of long-period MW Cepheids.« less

A 2.4% Determination of the Local Value of the Hubble Constant

NASA Astrophysics Data System (ADS)

Riess, Adam G.; Macri, Lucas M.; Hoffmann, Samantha L.; Scolnic, Dan; Casertano, Stefano; Filippenko, Alexei V.; Tucker, Brad E.; Reid, Mark J.; Jones, David O.; Silverman, Jeffrey M.; Chornock, Ryan; Challis, Peter; Yuan, Wenlong; Brown, Peter J.; Foley, Ryan J.

2016-07-01

We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample of reliable SNe Ia having a Cepheid-calibrated distance to a total of 19; these in turn leverage the magnitude-redshift relation based on ˜300 SNe Ia at z < 0.15. All 19 hosts as well as the megamaser system NGC 4258 have been observed with WFC3 in the optical and NIR, thus nullifying cross-instrument zeropoint errors in the relative distance estimates from Cepheids. Other noteworthy improvements include a 33% reduction in the systematic uncertainty in the maser distance to NGC 4258, a larger sample of Cepheids in the Large Magellanic Cloud (LMC), a more robust distance to the LMC based on late-type detached eclipsing binaries (DEBs), HST observations of Cepheids in M31, and new HST-based trigonometric parallaxes for Milky Way (MW) Cepheids. We consider four geometric distance calibrations of Cepheids: (I) megamasers in NGC 4258, (II) 8 DEBs in the LMC, (III) 15 MW Cepheids with parallaxes measured with HST/FGS, HST/WFC3 spatial scanning and/or Hipparcos, and (IV) 2 DEBs in M31. The Hubble constant from each is 72.25 ± 2.51, 72.04 ± 2.67, 76.18 ± 2.37, and 74.50 ± 3.27 km s-1 Mpc-1, respectively. Our best estimate of H 0 = 73.24 ± 1.74 km s-1 Mpc-1 combines the anchors NGC 4258, MW, and LMC, yielding a 2.4% determination (all quoted uncertainties include fully propagated statistical and systematic components). This value is 3.4σ higher than 66.93 ± 0.62 km s-1 Mpc-1 predicted by ΛCDM with 3 neutrino flavors having a mass of 0.06 eV and the new Planck data, but the discrepancy reduces to 2.1σ relative to the prediction of 69.3 ± 0.7 km s-1 Mpc-1 based on the comparably precise combination of WMAP+ACT+SPT+BAO observations, suggesting that systematic uncertainties in CMB radiation measurements may play a role in the tension. If we take the conflict between Planck high-redshift measurements and our local determination of H 0 at face value, one plausible explanation could involve an additional source of dark radiation in the early universe in the range of ΔN eff ≈ 0.4-1. We anticipate further significant improvements in H 0 from upcoming parallax measurements of long-period MW Cepheids. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

Antiphospholipid Antibodies and Recurrent Thrombotic Events: Persistence and Portfolio.

PubMed

Amory, Colum F; Levine, Steven R; Brey, Robin L; Gebregziabher, Mulugeta; Tuhrim, Stanley; Tilley, Barbara C; Simpson, Ann-Catherin C; Sacco, Ralph L; Mohr, Jay P

2015-01-01

There are very limited prospective data on the significance of persistent antiphospholipid antibodies (aPL) and recurrent thrombo-occlusive events (TOEs). We investigated the prognostic value of (1) 2 newer aPL assays, (2) an aPL portfolio and (3) persistent aPL positivity following stroke. A total of 1,770 subjects from the APASS-WARSS study underwent further aPL testing for antibodies to phosphatidylserine (aPS) and anti-β2-glycoprotein-I (anti-β2GPI) from stored sera. Follow-up aPL status was also tested in a subset of subjects. Primary analysis was based on time to any TOE (ischemic stroke, myocardial infarction, transient ischemic attack, deep vein thrombosis, pulmonary embolism or systemic arterial occlusion)/death at 2 years. Cox proportional hazard analyses assessed whether aPL independently related to outcome. Persistent anti-β2GPI decreased the time to TOE/death after adjustment for potential confounders (hazards ratio (HR) 2.86, 95% CI 1.21-6.76, p = 0.017). When persistent anti-β2GPI was combined with another persistently positive aPL, time to TOE/death was also reduced (HR 3.79, 95% CI 1.18-12.14, p = 0.025). Neither persistent anticardiolipin antibodies nor persistent aPS alone nor a single positive anti-β2GPI nor aPS was associated with decreased time to TOE/death. No single positive aPL, portfolio of baseline aPL or any persistent aPL increased the rate of TOE/death. Rates of TOE/death were not influenced by aPL results at baseline or follow-up. Persistent anti-β2GPI alone, and with persistent second aPL, was independently associated with decreased time to TOE/death. Persistent aPL, an aPL portfolio and newer aPL in ischemic stroke patients are not helpful in predicting an increased rate of recurrent TOEs. © 2015 S. Karger AG, Basel.

VizieR Online Data Catalog: New planetary nebulae in LMC (Reid+, 2006)

NASA Astrophysics Data System (ADS)

Reid, W. A.; Parker, Q. A.

2006-05-01

Over the last few years, we have specially constructed additional deep, homogeneous, narrow-band H and matching broad-band 'SR' (Short Red) maps of the entire central 25deg2 of the LMC. These unique maps were obtained from co-adding 12 well-matched UKST 2-h Hα exposures and six 15-min equivalent SR-band exposures on the same field using high-resolution Tech-Pan film. The 'SuperCOSMOS' plate-measuring machine at the Royal Observatory Edinburgh (Hambly et al., 2001MNRAS.326.1279) has scanned, co-added and pixel-matched these exposures, creating 10-m (0.67-arcsec) pixel data which goes 1.35 and 1mag deeper than individual exposures, achieving the full canonical Poissonian depth gain, e.g. Bland-Hawthorn, Shopbell & Malin (1993AJ....106.2154B). This gives a depth ~21.5 for the SR images and Requiv~22 for Hα (4.5x10-17erg/cm2/s/{AA}) which is at least 1-mag deeper than the best wide-field narrow-band LMC images currently available. (2 data files).

The MACHO Project LMC Variable Star Inventory. VIII. The Recent Star Formation History of the Large Magellanic Cloud from the Cepheid Period Distribution

NASA Astrophysics Data System (ADS)

Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Bersier, D. F.; Cook, K. H.; Freeman, K. C.; Griest, K.; Guern, J. A.; Lehner, M.; Marshall, S. L.; Minniti, D.; Peterson, B. A.; Pratt, M. R.; Quinn, P. J.; Rodgers, A. W.; Stubbs, C. W.; Sutherland, W.; Tomaney, A.; Vandehei, T.; Welch, D. L.

1999-02-01

We present an analysis of the period distribution of about 1800 Cepheids in the LMC, based on data obtained by the MACHO microlensing experiment and on a previous catalog by C. H. Payne Gaposchkin. Using stellar evolution and pulsation models, we construct theoretical period-frequency distributions that are compared with the observations. These models reveal that a significant burst of star formation has occurred recently in the LMC (~1.15x10^8 yr). We also show that during the last ~10^8 yr, the main center of star formation has been propagating from southeast to northwest along the bar. We find that the evolutionary masses of Cepheids are still smaller than pulsation masses by ~7% and that the red edge of the Cepheid instability strip could be slightly bluer than indicated by theory. There are approximately 600 Cepheids with periods below ~2.5 days that cannot be explained by evolution theory. We suggest that they are anomalous Cepheids and that a number of these stars are double-mode Cepheids.

Determinants of Treatment Abandonment in Childhood Cancer: Results from a Global Survey

PubMed Central

Lam, Catherine G.; Kaur, Geetinder; Itriago, Elena; Ribeiro, Raul C.; Arora, Ramandeep S.

2016-01-01

Background Understanding and addressing treatment abandonment (TxA) is crucial for bridging the pediatric cancer survival gap between high-income (HIC) and low-and middle-income countries (LMC). In childhood cancer, TxA is defined as failure to start or complete curative cancer therapy and known to be a complex phenomenon. With rising interest on causes and consequences of TxA in LMC, this study aimed to establish the lay-of-the-land regarding determinants of TxA globally, perform and promote comparative research, and raise awareness on this subject. Methods Physicians (medical oncologists, surgeons, and radiation therapists), nurses, social workers, and psychologists involved in care of children with cancer were approached through an online survey February-May 2012. Queries addressed social, economic, and treatment-related determinants of TxA. Free-text comments were collected. Descriptive and qualitative analyses were performed. Appraisal of overall frequency, burden, and predictors of TxA has been reported separately. Results 581 responses from 101 countries were obtained (contact rate = 26%, cooperation rate = 70%). Most respondents were physicians (86%), practicing pediatric hematology/oncology (86%) for >10 years (54%). Providers from LMC considered social/economic factors (families’ low socioeconomic status, low education, and long travel time), as most influential in increasing risk of TxA. Treatment-related considerations such as preference for complementary and alternative medicine and concerns about treatment adverse effects and toxicity, were perceived to play an important role in both LMC and HIC. Perceived prognosis seemed to mediate the role of other determinants such as diagnosis and treatment phase on TxA risk. For example, high-risk of TxA was most frequently reported when prognosis clearly worsened (i.e. lack of response to therapy, relapse), or conversely when the patient appeared improved (i.e. induction completed, mass removed), as well as before aggressive/mutilating surgery. Provider responses allowed development of an expanded conceptual model of determinants of TxA; one which illustrates established and emerging individual, family, center, and context specific factors to be considered in order to tackle this problem. Emerging factors included vulnerability, family dynamics, perceptions, center capacity, public awareness, and governmental healthcare financing, among others. Conclusion TxA is a complex and multifactorial phenomenon. With increased recognition of the role of TxA on global pediatric cancer outcomes, factors beyond social/economic status and beliefs have emerged. Our results provide insights regarding the role of established determinants of TxA in different geographical and economic contexts, allow probing of key determinants by deliberating their mechanisms, and allow building an expanded conceptual model of established and emerging determinants TxA. PMID:27736871

LMC O Supergiant Mass Loss Rates Determined from P V, S V and IR Excesses

NASA Astrophysics Data System (ADS)

Massa, Derck; Prinja, R.; Fullerton, A.; Lennon, D.

2012-05-01

We use HST/STIS and FUSE spectra and Spitzer/IRAC photometry to obtain independent mass loss rates for 7 LMC O supergiants. The mass loss rates are derived from the P Cygni profiles of the P V 1118, 1128 resonance doublet, the S V 1502 and N IV 1718 excited state lines, and the IR excesses of a combination of ground based and Spitzer photometry. The different mass loss rates are compared to each other and to theoretical expectations. We discuss the causes for the differences between the various determinations.

Planck early results. XVII. Origin of the submillimetre excess dust emission in the Magellanic Clouds

NASA Astrophysics Data System (ADS)

Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Bernard, J.-P.; Bersanelli, M.; Bhatia, R.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bot, C.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Cabella, P.; Cardoso, J.-F.; Catalano, A.; Cayón, L.; Challinor, A.; Chamballu, A.; Chiang, L.-Y.; Chiang, C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Couchot, F.; Coulais, A.; Crill, B. P.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Dobashi, K.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Fukui, Y.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hovest, W.; Hoyland, R. J.; Huffenberger, K. M.; Jaffe, A. H.; Jones, W. C.; Juvela, M.; Kawamura, A.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knox, L.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leach, S.; Leonardi, R.; Leroy, C.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; MacTavish, C. J.; Madden, S.; Maffei, B.; Mandolesi, N.; Mann, R.; Maris, M.; Martínez-González, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Onishi, T.; Osborne, S.; Pajot, F.; Paladini, R.; Paradis, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Poutanen, T.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Savini, G.; Scott, D.; Seiffert, M. D.; Smoot, G. F.; Starck, J.-L.; Stivoli, F.; Stolyarov, V.; Sudiwala, R.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Torre, J.-P.; Tristram, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Varis, J.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Wilkinson, A.; Ysard, N.; Yvon, D.; Zacchei, A.; Zonca, A.

2011-12-01

The integrated spectral energy distributions (SED) of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) appear significantly flatter than expected from dust models based on their far-infrared and radio emission. The still unexplained origin of this millimetre excess is investigated here using the Planck data. The integrated SED of the two galaxies before subtraction of the foreground (Milky Way) and background (CMB fluctuations) emission are in good agreement with previous determinations, confirming the presence of the millimetre excess. In the context of this preliminary analysis we do not propose a full multi-component fitting of the data, but instead subtract contributions unrelated to the galaxies and to dust emission. The background CMB contribution is subtracted using an internal linear combination (ILC) method performed locally around the galaxies. The foreground emission from the Milky Way is subtracted as a Galactic Hi template, and the dust emissivity is derived in a region surrounding the two galaxies and dominated by Milky Way emission. After subtraction, the remaining emission of both galaxies correlates closely with the atomic and molecular gas emission of the LMC and SMC. The millimetre excess in the LMC can be explained by CMB fluctuations, but a significant excess is still present in the SMC SED. The Planck and IRAS-IRIS data at 100 μm are combined to produce thermal dust temperature and optical depth maps of the two galaxies. The LMC temperature map shows the presence of a warm inner arm already found with the Spitzer data, but which also shows the existence of a previously unidentified cold outer arm. Several cold regions are found along this arm, some of which are associated with known molecular clouds. The dust optical depth maps are used to constrain the thermal dust emissivity power-law index (β). The average spectral index is found to be consistent with β = 1.5 and β = 1.2 below 500μm for the LMC and SMC respectively, significantly flatter than the values observed in the Milky Way. Also, there is evidence in the SMC of a further flattening of the SED in the sub-mm, unlike for the LMC where the SED remains consistent with β = 1.5. The spatial distribution of the millimetre dustexcess in the SMC follows the gas and thermal dust distribution. Different models are explored in order to fit the dust emission in the SMC. It is concluded that the millimetre excess is unlikely to be caused by very cold dust emission and that it could be due to a combination of spinning dust emission and thermal dust emission by more amorphous dust grains than those present in our Galaxy. Corresponding author: J.-P. Bernard, e-mail: jean-philippe.bernard@cesr.fr

Active avoidance requires inhibitory signaling in the rodent prelimbic prefrontal cortex

PubMed Central

Bravo-Rivera, Christian; Rodriguez-Romaguera, Jose; Pagan-Rivera, Pablo A; Burgos-Robles, Anthony; Roman-Ortiz, Ciorana; Quirk, Gregory J

2018-01-01

Much is known about the neural circuits of conditioned fear and its relevance to understanding anxiety disorders, but less is known about other anxiety-related behaviors such as active avoidance. Using a tone-signaled, platform-mediated avoidance task, we observed that pharmacological inactivation of the prelimbic prefrontal cortex (PL) delayed avoidance. Surprisingly, optogenetic silencing of PL glutamatergic neurons did not delay avoidance. Consistent with this, inhibitory but not excitatory responses of rostral PL neurons were associated with avoidance training. To test the importance of these inhibitory responses, we optogenetically stimulated PL neurons to counteract the tone-elicited reduction in firing rate. Photoactivation of rostral (but not caudal) PL neurons at 4 Hz impaired avoidance. These findings suggest that inhibitory responses of rostral PL neurons signal the avoidability of a potential threat and underscore the importance of designing behavioral optogenetic studies based on neuronal firing responses. PMID:29851381

Enhancement of visible photoluminescence in the SiNx films by SiO2 buffer and annealing

NASA Astrophysics Data System (ADS)

Xu, M.; Xu, S.; Chai, J. W.; Long, J. D.; Ee, Y. C.

2006-12-01

The authors report a simple method to significantly enhance the photoluminescence (PL) of SiNx films by incorporating a SiO2 buffer and annealing treatment under N2 protection. Strong visible PL is achieved with annealing temperature above 650°C. Optimal PL is obtained at 800°C. The composition and structure analysis reveal that strong PL is directly related to the content of the Si-O and Si-N bonds in the SiNx films. These bonds provide effective luminescent centers and passivate the interface between Si core and the surrounding oxide.

Impact of roasting on the flavan-3-ol composition, sensory-related chemistry, and in vitro pancreatic lipase inhibitory activity of cocoa beans.

PubMed

Stanley, Todd H; Van Buiten, Charlene B; Baker, Scott A; Elias, Ryan J; Anantheswaran, Ramaswamy C; Lambert, Joshua D

2018-07-30

Roasting is an important cocoa processing step, but has been reported to reduce the polyphenol content in the beans. We investigated the impact of whole-bean roasting on the polyphenol content, aroma-related chemistry, and in vitro pancreatic lipase (PL) inhibitory activity of cocoa under a range of roasting conditions. Total phenolics, (-)-epicatechin, and proanthocyanidin (PAC) dimer - pentamer content was reduced by roasting. By contrast, roasting at 150 °C or greater increased the levels of catechin and PAC hexamers and heptamers. These compounds have greater PL inhibitory potency. Consistent with these changes in PAC composition and this previous data, we found that roasting at 170 °C time-dependently increased PL inhibitory activity. Cocoa aroma-related compounds increased with roasting above 100 °C, whereas deleterious sensory-related compounds formed at more severe temperatures. Our results indicate that cocoa roasting can be optimized to increase the content of larger PACs and anti-PL activity, while maintaining a favorable aroma profile. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Most Metal-poor Stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Schlaufman, Kevin C.

2018-06-01

The chemical abundances of the most metal-poor stars in a galaxy can be used to investigate the earliest stages of its formation and chemical evolution. Differences between the abundances of the most metal-poor stars in the Milky Way and in its satellite dwarf galaxies have been noted and provide the strongest available constraints on the earliest stages of general galactic chemical evolution models. However, the masses of the Milky Way and its satellite dwarf galaxies differ by four orders of magnitude, leaving a gap in our knowledge of the early chemical evolution of intermediate mass galaxies like the Magellanic Clouds. To close that gap, we have initiated a survey of the metal-poor stellar populations of the Magellanic Clouds using the mid-infrared metal-poor star selection of Schlaufman & Casey (2014). We have discovered the three most metal-poor giant stars known in the Large Magellanic Cloud (LMC) and reobserved the previous record holder. The stars have metallicities in the range -2.70 < [Fe/H] < -2.00 and three show r-process enhancement: one has [Eu II/Fe] = +1.65 and two others have [Eu II/Fe] = +0.65. The probability that four randomly selected very metal-poor stars in the halo of the Milky Way are as r-process enhanced is 0.0002. For that reason, the early chemical enrichment of the heaviest elements in the LMC and Milky Way were qualitatively different. It is also suggestive of a possible chemical link between the LMC and the ultra-faint dwarf galaxies nearby with evidence of r-process enhancement (e.g., Reticulum II and Tucana III). Like Reticulum II, the most metal-poor star in our LMC sample is the only one not enhanced in r-process elements.

A modern search for Wolf-Rayet stars in the Magellanic Clouds: First results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massey, Philip; Neugent, Kathryn F.; Morrell, Nidia

Over the years, directed surveys and incidental spectroscopy have identified 12 Wolf-Rayet (WR) stars in the Small Magellanic Cloud (SMC) and 139 in the Large Magellanic Cloud (LMC), numbers which are often described as 'essentially complete'. Yet, new WRs are discovered in the LMC almost yearly. We have therefore initiated a new survey of both Magellanic Clouds using the same interference-filter imaging technique previously applied to M31 and M33. We report on our first observing season, in which we have successfully surveyed ∼15% of our intended area of the SMC and LMC. Spectroscopy has confirmed nine newly found WRs inmore » the LMC (a 6% increase), including one of WO-type, only the third known in that galaxy and the second to be discovered recently. The other eight are WN3 stars that include an absorption component. In two, the absorption is likely from an O-type companion, but the other six are quite unusual. Five would be classified naively as 'WN3+O3 V', but such a pairing is unlikely given the rarity of O3 stars, the short duration of this phase (which is incommensurate with the evolution of a companion to a WN star), and because these stars are considerably fainter than O3 V stars. The sixth star may also fall into this category. CMFGEN modeling suggests these stars are hot, bolometrically luminous, and N-rich like other WN3 stars, but lack the strong winds that characterize WNs. Finally, we discuss two rare Of?p stars and four Of supergiants we found, and propose that the B[e] star HD 38489 may have a WN companion.« less

Study of the Correlations and the MAXI Hardness Ratio between the Anomalous and Normal Low States of LMC X-3

NASA Astrophysics Data System (ADS)

Torpin, Trevor; Boyd, Patricia T.; Smale, Alan P.

2015-01-01

The bright, unusual black-hole X-ray binary LMC X-3 has been monitored virtually continuously by the Japanese MAXI X-ray All-Sky Monitor aboard the International Space Station (Matsuoka, et al., PASJ, 2009) from August 2009 to the present. Comparison with RXTE PCA and ASM light curves during the ~2.33-year period of overlap demonstrate that despite slight differences in energy-band boundaries both the ASM and MAXI faithfully reproduce characteristics of the high-amplitude, nonperiodic long-term variability, on the order of 100-300 days, clearly seen in the more sensitive PCA monitoring. The mechanism for this variability at a timescale many times longer than the 1.7-day orbital period is still unknown. Models to explain the long-term variability invoke mechanisms such as changes in mass transfer rate, and/or a precessing warped accretion disk. Observations of LMC X-3 have not definitely determined whether wind accretion or Roche-love overflow is the driver of the long-term variability. Recent MAXI monitoring of LMC X-3 includes excellent coverage of a rare anomalous low state (ALS) where the X-ray source cannot be distinguished from the background, as well as several normal low states, in which the source count rate passes smoothly through a low, yet detectable value. Pointed Swift XRT and UVOT observations also sample this ALS and one normal low state well. We combine these data sets to study the correlations between the wavelength regimes observed during the ALS versus the normal low. We also examine the behavior of the X-ray hardness ratios using XRT and MAXI monitoring data during the ALS versus the normal low state.

The Contribution of Thermally-Pulsing Asymptotic Giant Branch and Red Supergiant Starts to the Luminosities of the Magellanic Clouds at 1-24 micrometers

NASA Technical Reports Server (NTRS)

Melbourne, J.; Boyer, Martha L.

2013-01-01

We present the near-through mid-infrared flux contribution of thermally-pulsing asymptotic giant branch (TP-AGB) and massive red supergiant (RSG) stars to the luminosities of the Large and Small Magellanic Clouds (LMC and SMC, respectively). Combined, the peak contribution from these cool evolved stars occurs at approx 3 - 4 micron, where they produce 32% of the SMC light, and 25% of the LMC flux. The TP-AGB star contribution also peaks at approx 3 - 4 micron and amounts to 21% in both galaxies. The contribution from RSG stars peaks at shorter wavelengths, 2.2 micron, where they provide 11% of the SMC flux, and 7% for the LMC. Both TP-AGB and RSG stars are short lived, and thus potentially impose a large stochastic scatter on the near-IR derived mass-to-light (M/L) ratios of galaxies at rest-frame 1 - 4 micron. To minimize their impact on stellar mass estimates, one can use the M/L ratio at shorter wavelengths (e.g., at 0.8 - 1 micron). At longer wavelengths (much > 8 micron), emission from dust in the interstellar medium dominates the flux. In the LMC, which shows strong polycyclic aromatic hydrocarbon (PAH) emission at 8 micron, TP-AGB and RSG contribute less than 4% of the 8 micron flux. However, 19% of the SMC 8 micron flux is from evolved stars, nearly half of which is produced by the rarest, dustiest, carbon-rich TP-AGB stars. Thus, star formation rates of galaxies, based on an 8 micron flux (e.g., observed-frame 24 micron at z = 2), may be biased modestly high, especially for galaxies with little PAH emission.

MYSST: Mapping Young Stars in Space and Time - The HII Complex N44 in the LMC

NASA Astrophysics Data System (ADS)

Gouliermis, Dimitrios

2016-10-01

The stellar initial mass function (IMF), and the timescale and lengthscale of star formation (SF) are critical issues for our understanding of how stars form. Low-mass pre-main-sequence (PMS) stars, having typical contraction times on the order of a few 10 Myr, are the live chronometers of the SF process and primary informants on the low-mass IMF of their host clusters. Our studies show that young star clusters, embedded in star-forming regions of the Large Magellanic Cloud (LMC), encompass rich samples of PMS stars, sufficient to study clustered SF in low-metallicities with optical HST photometry. Yet, the lack of a complete comprehensive stellar sample retains important questions about the universality of the IMF, and the time- and length-scale of SF across a typical molecular cloud unanswered. We propose to address these issues by employing both ACS and WFC3 with their high sensitivity and spatial resolving power to obtain deep photometry (m_555 29 mag) of the LMC star-forming complex N44. We will accomplish a detailed mapping of PMS stars that will trace the whole hierarchy of star formation springing from one giant molecular cloud. Our analysis will provide an unbiased determination of the timescale for SF and the sub-solar IMF down to the hydrogen burning limit in a variety of clustering scales for the first time. Our findings will have a significant impact on our comprehensive understanding of SF in the low-metallicity environment of the LMC. We maximize the HST observing efficiency using both ACS/WFC and WFC3/UVIS in parallel for the simultaneous observations of N44, its ensemble of HII regions and their young stellar clusters in the same F555W and F814W filters.

Did LMC X-3 Undergo a 'Her X-1-like' Anomalous Low State?

NASA Technical Reports Server (NTRS)

Boyd, Patricia t.

2008-01-01

The black hole X-ray binary LMC X-3 has been monitored by the Rossi X-ray Timing Explorer (RXTE) from its launch to the present by the All-Sky Monitor (ASM). This well-sampled light curve is supplemented by frequent pointed observations with the PCA and HEXTE instruments which provide improved sensitivity, time resolution and spectral information. The long-term X-ray luminosity of the system is strongly modulated on timescales of hundreds of days. The mean 2-10 kev X-ray flux varies by a factor of more than 100 during this long-term cycle. This variability has been attributed to the precession of a bright, tilted, and warped accretion disk---the mechanism also invoked to explain the 35-day super-orbital period in the X-ray binary pulsar system Her X-1. The ASM light curve displays a unique episode, starting in December 2003, during which LMC X-3 displayed a very low, nearly constant flux, for about 80 days. This is markedly different from the typical low-flux excursions in LMC X-3, which smoothly evolve toward and then away from a minimum flux on about a 10-day time scale. The character of the long-term variability, as measured by amplitude and characteristic time scale, is not the same after this long low state as it was before. Similar shifts in long-term period and amplitude are seen after the so-called "anomalous low states" in Her X-1, when the 35-day X-ray modulation ceases for an unpredictable length of time. These similar shifts in the long-term amplitude and timescale in the two systems suggests they share a similar mechanism which gives rise to the anomalous low states

ELEMENTAL DEPLETIONS IN THE MAGELLANIC CLOUDS AND THE EVOLUTION OF DEPLETIONS WITH METALLICITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tchernyshyov, Kirill; Meixner, Margaret; Seale, Jonathan

2015-10-01

We present a study of the composition of gas and dust in the Large and Small Magellanic Clouds (LMC and SMC) using UV absorption spectroscopy. We measure P ii and Fe ii along 84 spatially distributed sightlines toward the MCs using archival Far Ultraviolet Spectroscopic Explorer observations. For 16 of those sightlines, we also measure Si ii, Cr ii, and Zn ii from new Hubble Space Telescope Cosmic Origins Spectrograph observations. We analyze these spectra using a new spectral line analysis technique based on a semi-parametric Voigt profile model. We have combined these measurements with H i and H{sub 2}more » column densities and reference stellar abundances from the literature to derive gas-phase abundances, depletions, and gas-to-dust ratios (GDRs). Of our 84 P and 16 Zn measurements, 80 and 13, respectively, are depleted by more than 0.1 dex, suggesting that P and Zn abundances are not accurate metallicity indicators at and above the metallicity of the SMC. Si, Cr, and Fe are systematically less depleted in the SMC than in the Milky Way (MW) or LMC. The minimum Si depletion in the SMC is consistent with zero. We find GDR ranges of 190–565 in the LMC and 480–2100 in the SMC, which is broadly consistent with GDRs from the literature. These ranges represent actual location to location variation and are evidence of dust destruction and/or growth in the diffuse neutral phase of the interstellar medium. Where they overlap in metallicity, the gas-phase abundances of the MW, LMC, and SMC and damped Lyα systems evolve similarly with metallicity.« less

New Observations of Candidate Herbig Ae/Be Stars in the LMC and SMC

NASA Astrophysics Data System (ADS)

Bjorkman, K. S.; Wisniewski, J. P.; Bjorkman, J. E.; Hesselbach, E. N.

2005-12-01

Based on analysis of the EROS microlensing data set, Lamers, Beaulieu, & de Wit (1999) and de Wit, Beaulieu, & Lamers (2002) identified 21 candidate Herbig Ae/Be (HAeBe) stars in the Large Magellanic Cloud (LMC). They based the selection of candidates on the irregular photometric variability exhibited by these stars, which bore some resemblance to the variability exhibited by known Galactic HAeBe stars. The candidate stars identified were designated as EROS LMC HAeBe Candidates, or ELHCs. A smaller number (7) of candidate stars identified in the SMC (Beaulieu et al. 2001; de Wit et al. 2003) were similarly designated ESHCs. Using the CTIO 0.9m telescope and imaging camera, we obtained B, V, R, and Hα photometry of 2 fields in the LMC encompassing 12 of the ELHCs. We used the CTIO 4m Blanco telescope with the Hydra multi-object spectrograph to obtain optical spectroscopy of all the ELHC stars as well as the ESHC stars. Further observations included JHK photometry of both the ELHC and ESHC fields using the CTIO 4m plus the ISPI infrared imager. We will discuss the results from our observations, and comment on the implications for the tentative identification of these stars as candidate HAeBe stars. We will also compare our results with the recent findings of de Wit et al. (2005). This work has been supported in part by NASA LTSA grant (KSB) NAG5-8054 and NASA GSRP Fellowship (JPW) NGT5-5069 to the University of Toledo. We thank the NOAO TAC for providing observing time for this project, and for providing travel support for JPW.

Asthma and asthma-related health care utilization among people without disabilities and people with physical disabilities.

PubMed

Stransky, Michelle L; McGrath, Robert; Reichard, Amanda; McClain, Monica; Phillips, Kimberly G; Houtenville, Andrew; Drum, Charles E

2016-10-01

Previous research has shown that people with disabilities have higher rates of some chronic diseases and receive poorer disease-specific care than their counterparts without disabilities. Yet, little is known about the relationship between asthma and disability. This study examines whether differences in the prevalence of asthma, asthma flare, and asthma-related measures of health care quality, utilization and cost exist among people with physical limitations (PL) and without any limitations. Data from the 2004-2010 Medical Expenditure Panel Survey were pooled to compare outcomes for working-age adults (18-64) with PL to those with no limitations. People with PL had higher rates of asthma (13.8% vs. 5.9%, p < 0.001) and recent asthma flare (52.6% vs. 39.6%, p < 0.001) than people without limitations. There were no differences in health care quality, utilization or cost between people with PL and people without limitations in multivariate analyses. Although there are no differences in asthma-related quality or utilization of health care, people with PL have poorer asthma control than people without limitations. Research is needed to determine what factors (e.g., focus on other acute ailments, perceptions that asthma control cannot improve) are related to this outcome. Future research must also examine differences in asthma severity, and its impact on asthma control and health care-related outcomes, among people with and without disabilities. Copyright © 2016 Elsevier Inc. All rights reserved.

Behavioural and physiological mechanisms of polarized light sensitivity in birds.

PubMed

Muheim, Rachel

2011-03-12

Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system.

Behavioural and physiological mechanisms of polarized light sensitivity in birds

PubMed Central

Muheim, Rachel

2011-01-01

Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system. PMID:21282180

Photoluminescence Intermittency and Photo-Bleaching of Single Colloidal Quantum Dot.

PubMed

Qin, Haiyan; Meng, Renyang; Wang, Na; Peng, Xiaogang

2017-04-01

Photoluminescence (PL) blinking of single colloidal quantum dot (QD)-PL intensity switching between different brightness states under constant excitation-and photo-bleaching are roadblocks for most applications of QDs. This progress report shall treat PL blinking and photo-bleaching both as photochemical events, namely, PL blinking as reversible and photo-bleaching being irreversible ones. Most studies on single-molecule spectroscopy of QDs in literature are related to PL blinking, which invites us to concentrate our discussions on the PL blinking, including its brief history in 20 years, analysis methods, competitive mechanisms and different strategies to battle it. In terms of suppression of the PL blinking, wavefunction confinement-confining photo-generated electron and hole within the core and inner portion of the shell of a core/shell QD-demonstrates significant advantages. This strategy yields nearly non-blinking QDs with their emission peaks covering most part of the visible window. As expected, the resulting QDs from this new strategy also show substantially improved anti-bleaching features. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Human platelet lysate supports the formation of robust human periodontal ligament cell sheets.

PubMed

Tian, Bei-Min; Wu, Rui-Xin; Bi, Chun-Sheng; He, Xiao-Tao; Yin, Yuan; Chen, Fa-Ming

2018-04-01

The use of stem cell-derived sheets has become increasingly common in a wide variety of biomedical applications. Although substantial evidence has demonstrated that human platelet lysate (PL) can be used for therapeutic cell expansion, either as a substitute for or as a supplement to xenogeneic fetal bovine serum (FBS), its impact on cell sheet production remains largely unexplored. In this study, we manufactured periodontal ligament stem cell (PDLSC) sheets in vitro by incubating PDLSCs in sheet-induction media supplemented with various ratios of PL and FBS, i.e. 10% PL without FBS, 7.5% PL + 2.5% FBS, 5% PL + 5% FBS, 2.5% PL + 7.5% FBS or 10% FBS without PL. Cultures with the addition of all the designed supplements led to successful cell sheet production. In addition, all the resultant cellular materials exhibited similar expression profiles of matrix-related genes and proteins, such as collagen I, fibronectin and integrin β1. Interestingly, the cell components within sheets generated by media containing both PL and FBS exhibited improved osteogenic potential. Following in vivo transplantation, all sheets supported significant new bone formation. Our data suggest that robust PDLSC sheets can be produced by applying PL as either an alternative or an adjuvant to FBS. Further examination of the relevant influences of human PL that benefit cell behaviour and matrix production will pave the way towards optimized and standardized conditions for cell sheet production. Copyright © 2017 John Wiley & Sons, Ltd.

Oxidative degradation and non-enzymatic browning due to the interaction between oxidised lipids and primary amine groups in different marine PL emulsions.

PubMed

Lu, F S H; Nielsen, N S; Baron, C P; Jacobsen, C

2012-12-15

Due to the beneficial health effects of marine phospholipids (PL) there is an increasing industrial interest in using them for nutritional applications including emulsified foods. This study was undertaken to investigate both oxidative and hydrolytic stability of marine PL emulsions in relation to the chemical composition of the marine PL used. Moreover, non-enzymatic browning reactions were also investigated. Emulsions were prepared by high pressure homogenizer using different concentrations and sources of marine PL. In some formulations, fish oil was added in order to study the effect of increasing levels of triglycerides in the emulsions. The oxidative and hydrolytic stability of emulsions was investigated through measurement of peroxide value, free fatty acids, and (31)P NMR during storage at 2°C for up to 32 days. The oxidative stability of marine PL emulsions during storage was further investigated through the measurement of secondary volatile compounds by solid-phase microextraction (SPME) and dynamic headspace (DHS) connected to gas chromatography (GC-MS). Non-enzymatic browning reactions were investigated through the measurement of Strecker derived volatiles, colour changes and pyrrole content. The results suggested that the oxidative stability of marine PL emulsions was significantly influenced by the chemical composition and the concentration of marine PL used to prepare them. Emulsions with good oxidative stability could be prepared from marine PL of high purity and high content of PL and antioxidant and low TAG content. Copyright © 2012 Elsevier Ltd. All rights reserved.

Synthetic and natural plagioclases: iron variations and its influence on VNIR reflectance spectra

NASA Astrophysics Data System (ADS)

Carli, Cristian; Orlando, Andrea; Borini, Daniele; Giuli, Gabriele; Serventi, Giovanna; Pratesi, Giovanni; Sgavetti, Maria

2017-04-01

Besides being one of the most important rock-forming phases, plagioclase (pl) is a common surface mineral in several Solar System bodies. In particular, pl is present in meteorites and lunar samples, both in lunar Highland, where it is the dominant phase, and Maria samples. Moreover, pl has been detected in Martian meteorites, as well as in HEDs. In visible and near-infrared (VNIR) reflectance spectroscopy this phase is characterized by a crystal field (C.F.) absorption band in iron-bearing samples. In particular, Burns (1993) summarized the electronic absorptions due to iron, pointing out: 1) a broad absorption around 1.25 μm related to a C.F. transition due to Fe2+ replacing Ca2+ in seven-fold coordinated sites; 2) narrow absorptions around 0.4 μm related to tetrahedrally coordinated Fe3+ ions replacing Al in the tetrahedral sites. A better understanding of the spectral properties of Fe2+-pl can be an important tool to investigate the spectral influence of pl in regolith material in which it can be mixed with variable amount of other components with variable abundance. This goal can be reached working on synthetic pl with variable FeO and An contents, which must be well characterized to be sure about the attribution of absorption bands seen in reflectance spectra, as well as working on well characterized (in term of An, iron amount and Fe2+/Fe3+) terrestrial pl. Future rover mission will have onboard hyperspectral instrument working in the VNIR with relative high spatial resolution and, so, with the possibility of measured pl crystals. For this reason, working more in detail on iron bearing plagioclase can be an important task. Here, we present our results on synthetic An90 mol% pl with different iron contents (0, 0.5 and 1.0 FeO wt%) with the aim to investigate the effects of iron substitution on the VNIR spectra of pl. Reagent-grade oxides and carbonates reactants used as starting materials were thoroughly mixed to ensure homogeneity. Each experimental charge weighed about 200 mg. All the experiments have been carried out in a Deltech vertical gas-mixing (CO - CO2) quenching furnace equipped with an oxygen fugacity probe. Temperatures were in the 1395 - 1580 ˚ C range and run duration varied from 15 min to 48 hours. The synthesis procedure envisaged two stages: 1) preparation of a glass from the starting material at high temperature (1550 or 1580 ˚ C); 2) annealing at lower T (1395 ˚ C). The produced pl were grinded and sieved at about <100 μm, VNIR reflectance and EXAFS spectra have been acquired to define the reflectance spectra and the Fe2+/Fe3+ ratio on each experiment. Moreover, the obtained products were characterized by several techniques such as optical microscopy, XRD, SEM, EMPA, to assess the pl-crystallinity and its chemical composition. Spectra collected on synthetic samples are compared with those of natural pl, and the broad 1.25gμm C.F. absorption parameters have been related to Fe2+ abundance and Fe2+/Fe3+ ratio. Reference: Burns, R.G., 1993. Mineralogical Applications of Crystal Field Theory. Cambridge University Press, 551 pp.

Quantitative comparison of OSEM and penalized likelihood image reconstruction using relative difference penalties for clinical PET

NASA Astrophysics Data System (ADS)

Ahn, Sangtae; Ross, Steven G.; Asma, Evren; Miao, Jun; Jin, Xiao; Cheng, Lishui; Wollenweber, Scott D.; Manjeshwar, Ravindra M.

2015-08-01

Ordered subset expectation maximization (OSEM) is the most widely used algorithm for clinical PET image reconstruction. OSEM is usually stopped early and post-filtered to control image noise and does not necessarily achieve optimal quantitation accuracy. As an alternative to OSEM, we have recently implemented a penalized likelihood (PL) image reconstruction algorithm for clinical PET using the relative difference penalty with the aim of improving quantitation accuracy without compromising visual image quality. Preliminary clinical studies have demonstrated visual image quality including lesion conspicuity in images reconstructed by the PL algorithm is better than or at least as good as that in OSEM images. In this paper we evaluate lesion quantitation accuracy of the PL algorithm with the relative difference penalty compared to OSEM by using various data sets including phantom data acquired with an anthropomorphic torso phantom, an extended oval phantom and the NEMA image quality phantom; clinical data; and hybrid clinical data generated by adding simulated lesion data to clinical data. We focus on mean standardized uptake values and compare them for PL and OSEM using both time-of-flight (TOF) and non-TOF data. The results demonstrate improvements of PL in lesion quantitation accuracy compared to OSEM with a particular improvement in cold background regions such as lungs.

Pyridoxal 5'-phosphate, pyridoxal, and 4-pyridoxic acid in the paired serum and cerebrospinal fluid of children.

PubMed

Akiyama, Tomoyuki; Hayashi, Yumiko; Hanaoka, Yoshiyuki; Shibata, Takashi; Akiyama, Mari; Tsuchiya, Hiroki; Yamaguchi, Tokito; Kobayashi, Katsuhiro

2017-09-01

We quantified pyridoxal 5'-phosphate (PLP), pyridoxal (PL), and 4-pyridoxic acid (PA) in paired serum and cerebrospinal fluid (CSF) samples from children and investigated the effect of age on the concentrations and CSF-to-serum ratios of these vitamers. Serum and CSF samples prospectively collected from 49 pediatric patients were analyzed. PLP, PL, and PA were measured using high-performance liquid chromatography with fluorescence detection, using pre-column derivatization by semicarbazide. Effects of age on these vitamers, the PLP-to-PL ratio, CSF-to-serum PLP ratio, and CSF-to-serum PL ratio were evaluated using correlation analysis. The PLP, PL, and PA concentrations in the serum and CSF were higher at younger ages, except for CSF PA concentrations that were mostly below the limit of detection (<1.2nmol/l). The PLP-to-PL ratios in the serum and CSF correlated positively with age. The CSF-to-serum PLP ratio and CSF-to-serum PL ratio were independent of age. Age-related changes in PLP, PL, and PA in serum and in CSF from pediatric patients and CSF-to-serum ratios of PLP and PL demonstrated in this study will provide valuable information for evaluating PLP supply to the central nervous system from the peripheral blood. Copyright © 2017 Elsevier B.V. All rights reserved.

VizieR Online Data Catalog: The distance modulus of the LMC (Kovacs, 2000)

NASA Astrophysics Data System (ADS)

Kovacs, G.

2000-11-01

This table provides periods, intensity averaged V magnitudes and magnitude averaged V-Rc (Johnson V & Kron-Cousins R) colors of the MACHO LMC double-mode RR Lyrae variables employed in the above paper. For the calculation of the averages, an iterative 3-sigma condition was used to omit outliers. Further references (coordinates, amplitude ratios, etc.) to these variables can be found in Alcock et al. (1997ApJ...482...89A) and in Alcock et al. (2000, Cat. ). Trasformation to the standard system has been performed in accordance with Alcock et al. (1999PASP..111.1539A). (1 data file).

Discovery of a 50 millisecond pulsar in the Large Magellanic Cloud

NASA Technical Reports Server (NTRS)

Seward, F. D.; Harnden, F. R., Jr.; Helfand, D. J.

1984-01-01

The present investigation is concerned with the discovery of a new pulsed X-ray source in the Large Magellanic Cloud (LMC) supernova remnant 0540 - 693. The SNR 0540 - 693 is one of three suspected Crab-like remnants in the LMC. The existing X-ray, optical, and radio observations of the remnant itself are discussed, and an analysis is conducted of the implications of the period, period derivative, and X-ray pulse shape of the new source. It is concluded that the pulsed X-ray source is almost certainly a young, isolated pulsar. Many of its properties are very similar to those of the Crab pulsar.

VizieR Online Data Catalog: OGLE eclipsing binaries in LMC (Wyrzykowski+, 2003)

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2003-09-01

We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive. (2 data files).

Imaging of four planetary nebulae in the Magellanic Clouds using the Hubble Space Telescope Faint Object Camera

NASA Technical Reports Server (NTRS)

Blades, J. C.; Barlow, M. J.; Albrecht, R.; Barbieri, C.; Boksenberg, A.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

1992-01-01

Using the Faint Object Camera on-board the Hubble Space Telescope, we have obtained images of four planetary nebulae (PNe) in the Magellanic Clouds, namely N2 and N5 in the SMC and N66 and N201 in the LMC. Each nebula was imaged through two narrow-band filters isolating forbidden O III 5007 and H-beta, for a nominal exposure time of 1000 s in each filter. In forbidden O III, SMC N5 shows a circular ring structure, with a peak-to-peak diameter of 0.26 arcsec and a FWHM of 0.35 arcsec while SMC N2 shows an elliptical ring structure with a peak-to-peak diameter of 0.26 x 0.21. The expansion ages corresponding to the observed structures in SMC N2 and N5 are of the order of 3000 yr. LMC N201 is very compact, with a FWHM of 0.2 arcsec in H-beta. The Type I PN LMC N66 is a multipolar nebula, with the brightest part having an extent of about 2 arcsec and with fainter structures extending over 4 arcsec.

A study of X-ray variation in LMC X-1 with Suzaku

NASA Astrophysics Data System (ADS)

Koyama, Shu; Kubota, Aya; Yamada, Shinya; Makishima, Kazuo; Tashiro, Makoto; Terada, Yukikatsu

LMC X-1 is one of persistently luminous X-ray black hole binaries accompanying an O type star. It has been observed repeatedly since its discovery by a rocket mission (Mark et al. 1969). LMC X-1 was observed with Suzaku in July 2009 for 120 ksec, and was detected over a wide X-ray band of 0.5-50 keV. As Steiner et al. (2012) reported, the source was in the soft state with 10% of Eddington luminosity, and the spectrum showed a clear iron line emission. We analyzed the Suzaku light curve and found intensity-correlated variations in the spectral hardness ratio on a timescale of 10 ksec. The variation is explained by 10% changes in the Comptonised emission, possibly accompanied by those in the narrow iron line. Assuming that the variation timescale corresponds to the viscous time scale of a standard accretion disk, these components are considered to have been emitted from a region at a distance of 150 Rg from the black hole. We also found 3 mHz QPO in lower energy band. We discuss geometry of accretion flow and interpretation of the low freqency QPO.

A New Threshold of Precision, 30 micro-arcsecond Parallaxes and Beyond

NASA Astrophysics Data System (ADS)

Riess, Adam

2017-08-01

The star formation histories of our nearest neighbors, M31 and theLMC, have been the subjects of intensive study but the 3% to 5%uncertainty in their distance limits knowledge of the ages of theirstructures to 0.6 to 1.0 Gyr. Two recent developments make it possibleto reach the previously unimaginable precision in distance of 1%. Thefirst is the development of DASH, which allows HST and WFC3 to slewtens of arcminutes between exposures within an orbit under gyrocontrol with enough precision to efficiently observe widelydistributed Cepheids.The second is the arrival of parallaxmeasurements from Gaia which are calibrating the individual distancesof long period Cepheids in the Milky Way to 2%. However, bandpass andzeropoint differences between ground and space observations wouldcompromise the precision of the Gaia parallaxes when building aCepheid bridge to our neighbors. We propose to dash around the LMC andM31 with WFC3 to rapidly collect 3 band photometry of over 70 longperiod Cepheids using the same photometric system as a calibration setof Cepheids in the Milky Way. These will nullify otherwise systematicerrors to extend the precision of Gaia beyond the Milky Way and clockthe formation of structures in M31 and the LMC to 100 Myr.

Egg Phospholipids and Cardiovascular Health

PubMed Central

Blesso, Christopher N.

2015-01-01

Eggs are a major source of phospholipids (PL) in the Western diet. Dietary PL have emerged as a potential source of bioactive lipids that may have widespread effects on pathways related to inflammation, cholesterol metabolism, and high-density lipoprotein (HDL) function. Based on pre-clinical studies, egg phosphatidylcholine (PC) and sphingomyelin appear to regulate cholesterol absorption and inflammation. In clinical studies, egg PL intake is associated with beneficial changes in biomarkers related to HDL reverse cholesterol transport. Recently, egg PC was shown to be a substrate for the generation of trimethylamine N-oxide (TMAO), a gut microbe-dependent metabolite associated with increased cardiovascular disease (CVD) risk. More research is warranted to examine potential serum TMAO responses with chronic egg ingestion and in different populations, such as diabetics. In this review, the recent basic science, clinical, and epidemiological findings examining egg PL intake and risk of CVD are summarized. PMID:25871489

Physical properties and evolution of GMCs in the Galaxy and the Magellanic Clouds

NASA Astrophysics Data System (ADS)

Onishi, Toshikazu

2015-08-01

Most stars are born as clusters in Giant Molecular Clouds (hereafter GMCs), and therefore the understanding of the evolution of GMCs in a galaxy is one of the key issues to investigate the evolution of the galaxy. The recent state-of-the-art radio telescopes have been enabling us to reveal the distribution of GMCs extensively in the Galaxy as well as in the nearby galaxies, and the physical properties and the evolution of the GMCs leading to cluster formations are actively being investigated. Here we present a review of studies of spatially resolved GMCs in the Galaxy and in the Large Magellanic Cloud (LMC), aiming at providing a template of GMC properties. For the Galactic GMCs, we will focus on the recent extensive survey of GMCs along the Galactic plane; the recent studies suggest cloud-cloud collision as mechanism of massive star formation. For the extra galactic GMCs, we will present recent high-resolution observations of GMCs in the LMC.The LMC is among the nearest star-forming galaxy (distance ~ 50kpc) and is almost face-on. From these aspects, it is becoming the most popular region for studying interstellar medium over an entire galaxy. For molecular gas, the NANTEN covered the entire LMC with a spatial resolution of 40 pc, revealing 272 molecular clouds whose mass ranges from ~104 to ~107 M⊙, which is the first uniform sample of GMCs in a single galaxy. Our Spitzer SAGE and Herschel HERITAGE surveys show that the interstellar medium has much smaller scale structures; full of filamentary and shell-like structures. In order to resolve the filamentary distributions and pre-stellar cores we definitely need to resolve clouds at sub-pc resolutions with ALMA and to cover regions of active cluster formation which are to be selected based on the Spitzer and Hershel data. Our ALMA targets in Cycle 1 and Cycle 2 include N159, which is the most intense and concentrated molecular cloud as shown by the brightest CO J=3-2 source in the LMC, and GMCs with different evolutionary stages. We present the maps of pre-stellar cores and linking filaments at sub-pc resolution and discuss the formation process of massive clusters.

Afghanistan: Narcotics and U.S. Policy

DTIC Science & Technology

2009-06-18

Defense Appropriation P.L. 110-116 FY2008 Bridge Fund P.L. 110-161 (Division L ) FY2008 Supplemental P.L. 110-252 (Title IX, Chapter 1) Total...Moreau and Sami Yousafzai, with Donatella Lorch, “Flowers of Destruction,” Newsweek, July 14, 2003; Andrew North, “Warlord Tells Police Chief to Go...Gen. Walter L . Sharp, Director of Strategic Plans (J-5), Before the House International Relations Committee, September 23, 2004. 81 House of Commons

Establishing the Galactic Centre distance using VVV Bulge RR Lyrae variables

NASA Astrophysics Data System (ADS)

Majaess, D.; Dékány, I.; Hajdu, G.; Minniti, D.; Turner, D.; Gieren, W.

2018-06-01

This study's objective was to exploit infrared VVV (VISTA Variables in the Via Lactea) photometry for high latitude RRab stars to establish an accurate Galactic Centre distance. RRab candidates were discovered and reaffirmed (n=4194) by matching Ks photometry with templates via χ 2 minimization, and contaminants were reduced by ensuring targets adhered to a strict period-amplitude (Δ Ks) trend and passed the Elorietta et al. classifier. The distance to the Galactic Centre was determined from a high latitude Bulge subsample (|b|>4°, R_{GC}=8.30 ± 0.36 kpc, random uncertainty is relatively negligible), and importantly, the comparatively low color-excess and uncrowded location mitigated uncertainties tied to the extinction law, the magnitude-limited nature of the analysis, and photometric contamination. Circumventing those problems resulted in a key uncertainty being the M_{Ks} relation, which was derived using LMC RRab stars (M_{Ks}=-(2.66± 0.06) log {P}-(1.03± 0.06), (J-Ks)0=(0.31± 0.04) log {P} + (0.35± 0.02), assuming μ _{0,LMC}=18.43). The Galactic Centre distance was not corrected for the cone-effect. Lastly, a new distance indicator emerged as brighter overdensities in the period-magnitude-amplitude diagrams analyzed, which arise from blended RRab and red clump stars. Blending may thrust faint extragalactic variables into the range of detectability.

A CHANDRA OBSERVATION OF SNR 0540 - 697

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seward, F. D.; Williams, R. M.; Chu, Y.-H.

2010-07-15

This paper describes a Chandra observation of SNR 0540 - 697 within the H II complex N159 in the Large Magellanic Cloud (LMC). Scattering from the nearby bright source LMC X-1, which obscures the western edge of the remnant, has been removed. Larger than previously believed, the 2.'0 x 2.'8 remnant is defined by optical filaments and two lobes of X-ray emission. A band of intervening material absorbs X-rays from the central part of the remnant. The N Lobe of the remnant is relatively bright and well defined, while emission from the S Lobe is much weaker. There is structuremore » within the N Lobe but no clear X-ray emission from an outer shell indicating a shock in the interstellar medium. The X-ray spectrum is thermal with emission lines from Fe, Mg, and Si. The observed temperature and luminosity of the hot gas are 0.6 keV and 6 x 10{sup 35} erg s{sup -1}, respectively. These are consistent with characteristics expected for older remnants. There is also diffuse thermal X-ray emission north of N159 extending into N160, evidence for a larger remnant or bubble.« less

Amygdala inputs to prefrontal cortex guide behavior amid conflicting cues of reward and punishment

PubMed Central

Burgos-Robles, Anthony; Kimchi, Eyal Y.; Izadmehr, Ehsan M.; Porzenheim, Mary Jane; Ramos-Guasp, William A.; Nieh, Edward H.; Felix-Ortiz, Ada C.; Namburi, Praneeth; Leppla, Christopher A.; Presbrey, Kara N.; Anandalingam, Kavitha K.; Pagan-Rivera, Pablo A.; Anahtar, Melodi; Beyeler, Anna; Tye, Kay M.

2017-01-01

Orchestrating appropriate behavioral responses in the face of competing signals that predict either rewards or threats in the environment is crucial for survival. The basolateral amygdala (BLA) and prelimbic (PL) medial prefrontal cortex (mPFC) have been implicated in reward-seeking and fear-related responses, but how information flows between these reciprocally-connected structures to coordinate behavior is unknown. We recorded neuronal activity from the BLA and PL while rats performed a task where in shock- and sucrose-predictive cues were simultaneously presented to induce competition. The correlated firing primarily displayed a BLA→PL directionality during the shock-associated cue. Furthermore, the majority of optogenetically-identified PL-projecting BLA neurons recorded encoded the shock-associated cue, and more accurately predicted behavioral responses during competition than unidentified BLA neurons. Finally, BLA→PL photostimulation increased freezing, whereas both chemogenetic and optogenetic inhibition reduced freezing. The BLA→PL circuit plays a critical role in governing the selection of behavioral responses in the face of competing signals. PMID:28436980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Samuel L.; Krishnan, Retheesh; Elbaradei, Ahmed

A detailed understanding of the photoluminescence (PL) from silicon nanocrystals (SiNCs) is convoluted by the complexity of the decay mechanism, including a stretched-exponential relaxation and the presence of both nanosecond and microsecond time scales. In this publication, we analyze the microsecond PL decay of size-resolved SiNC fractions in both full-spectrum (FS) and spectrally resolved (SR) configurations, where the stretching exponent and lifetime are used to deduce a probability distribution function (PDF) of decay rates. For the PL decay measured at peak emission, we find a systematic shift and narrowing of the PDF in comparison to the FS measurements. In amore » similar fashion, we resolve the PL lifetime of the ‘blue’, ‘peak’, and ‘red’ regions of the spectrum and map PL decays of different photon energy onto their corresponding location in the PDF. Furthermore, a general trend is observed where higher and lower photon energies are correlated with shorter and longer lifetimes, respectively, which we relate to the PL line width and electron-phonon coupling.« less

Water-Soluble Polymers with Strong Photoluminescence through an Eco-Friendly and Low-Cost Route.

PubMed

Guo, Zhaoyan; Ru, Yue; Song, Wenbo; Liu, Zhenjie; Zhang, Xiaohong; Qiao, Jinliang

2017-07-01

Photoluminescence (PL) of nonconjugated polymers brings a favorable opportunity for low-cost and nontoxic luminescent materials, while most of them still exhibit relatively weak emission. Strong PL from poly[(maleic anhydride)-alt-(vinyl acetate)] (PMV) from low-cost monomer has been found in organic solvents, yet the necessity of noxious solvents would hinder its practical applications. Herein, through a novel, eco-friendly, and one-step route, PMV-derived PL polymers can be fabricated with the highest quantum yield of 87% among water-soluble nonconjugated PL polymers ever reported. These PMV-derived polymers emit strong blue emission in both solutions and solids, and can be transformed into red-emission agents easily. These PL polymers exhibit application potentials in light-conversion agricultural films. It is assumed that this work not only puts forward a convenient preparation routine for nonconjugated polymers with high PL, but also provides an industrial application possibility for them. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-Temperature Photoluminescence of CsPbX 3 (X = Cl, Br, I) Nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diroll, Benjamin T.; Nedelcu, Georgian; Kovalenko, Maksym

2017-03-30

Recent synthetic developments have generated intense interest in the use of cesium lead halide perovskite nanocrystals for light-emitting applications. This work presents the photoluminescence (PL) of cesium lead halide perovskite nanocrystals with tunable halide composition recorded as function of temperature from 80 to 550 K. CsPbBr 3 nanocrystals show the highest resilience to temperature while chloride-containing samples show relatively poorer preservation of photoluminescence at elevated temperatures. Thermal cycling experiments show that PL loss of CsPbBr 3 is largely reversible at temperatures below 450 K, but shows irreversible degradation at higher temperatures. Time-resolved measurements of CsPbX 3 samples show an increasemore » in the PL lifetime with temperature elevation, consistent with exciton fission to form free carriers, followed by a decrease in the apparent PL lifetime due to trapping. In conclusion, PL persistence measurements and time-resolved spectroscopies implicate thermally assisted trapping, most likely to halogen vacancy traps, as the mechanism of reversible PL loss.« less

The PL6-Family Plasmids of Haloquadratum Are Virus-Related.

PubMed

Dyall-Smith, Mike; Pfeiffer, Friedhelm

2018-01-01

Plasmids PL6A and PL6B are both carried by the C23 T strain of the square archaeon Haloquadratum walsbyi , and are closely related (76% nucleotide identity), circular, about 6 kb in size, and display the same gene synteny. They are unrelated to other known plasmids and all of the predicted proteins are cryptic in function. Here we describe two additional PL6-related plasmids, pBAJ9-6 and pLT53-7, each carried by distinct isolates of Haloquadratum walsbyi that were recovered from hypersaline waters in Australia. A third PL6-like plasmid, pLTMV-6, was assembled from metavirome data from Lake Tyrell, a salt-lake in Victoria, Australia. Comparison of all five plasmids revealed a distinct plasmid family with strong conservation of gene content and synteny, an average size of 6.2 kb (range 5.8-7.0 kb) and pairwise similarities between 61-79%. One protein (F3) was closely similar to a protein carried by betapleolipoviruses while another (R6) was similar to a predicted AAA-ATPase of His 1 halovirus (His1V_gp16). Plasmid pLT53-7 carried a gene for a FkbM family methyltransferase that was not present in any of the other plasmids. Comparative analysis of all PL6-like plasmids provided better resolution of conserved sequences and coding regions, confirmed the strong link to haloviruses, and showed that their sequences are highly conserved among examples from Haloquadratum isolates and metagenomic data that collectively cover geographically distant locations, indicating that these genetic elements are widespread.

The VLT-FLAMES Tarantula Survey. IX. The interstellar medium seen through diffuse interstellar bands and neutral sodium&

NASA Astrophysics Data System (ADS)

van Loon, J. Th.; Bailey, M.; Tatton, B. L.; Maíz Apellániz, J.; Crowther, P. A.; de Koter, A.; Evans, C. J.; Hénault-Brunet, V.; Howarth, I. D.; Richter, P.; Sana, H.; Simón-Díaz, S.; Taylor, W.; Walborn, N. R.

2013-02-01

Context. The Tarantula Nebula (a.k.a. 30 Dor) is a spectacular star-forming region in the Large Magellanic Cloud (LMC), seen through gas in the Galactic disc and halo. Diffuse interstellar bands (DIBs) offer a unique probe of the diffuse, cool-warm gas in these regions. Aims: The aim is to use DIBs as diagnostics of the local interstellar conditions, whilst at the same time deriving properties of the yet-unknown carriers of these enigmatic spectral features. Methods: Spectra of over 800 early-type stars from the Very Large Telescope Flames Tarantula Survey (VFTS) were analysed. Maps were created, separately, for the Galactic and LMC absorption in the DIBs at 4428 and 6614 Å and - in a smaller region near the central cluster R 136 - neutral sodium (the Na i D doublet); we also measured the DIBs at 5780 and 5797 Å. Results: The maps show strong 4428 and 6614 Å DIBs in the quiescent cloud complex to the south of 30 Dor but weak absorption in the harsher environments to the north (bubbles) and near the OB associations. The Na maps show at least five kinematic components in the LMC and a shell-like structure surrounding R 136, and small-scale structure in the Milky Way. The strengths of the 4428, 5780, 5797 and 6614 Å DIBs are correlated, also with Na absorption and visual extinction. The strong 4428 Å DIB is present already at low Na column density but the 6614, 5780 and 5797 Å DIBs start to be detectable at subsequently larger Na column densities. Conclusions: The carriers of the 4428, 6614, 5780 and 5797 Å DIBs are increasingly prone to removal from irradiated gas. The relative strength of the 5780 and 5797 Å DIBs clearly confirm the Tarantula Nebula as well as Galactic high-latitude gas to represent a harsh radiation environment. The resilience of the 4428 Å DIB suggests its carrier is large, compact and neutral. Structure is detected in the distribution of cool-warm gas on scales between one and >100 pc in the LMC and as little as 0.01 pc in the Sun's vicinity. Stellar winds from the central cluster R 136 have created an expanding shell; some infalling gas is also detected, reminiscent of a galactic "fountain". Full Tables A.2-A.4 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/550/A108

A Spitzer Space Telescope Far-infrared Spectral Atlas of Compact Sources in the Magellanic Clouds. II. The Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

van Loon, Jacco Th.; Oliveira, Joana M.; Gordon, Karl D.; Sloan, G. C.; Engelbracht, C. W.

2010-04-01

We present far-infrared spectra, λ = 52-93 μm, obtained with the Spitzer Space Telescope in the spectral energy distribution mode of its Multiband Imaging Photometer for Spitzer instrument, of a selection of luminous compact far-infrared sources in the Small Magellanic Cloud (SMC). These comprise nine young stellar objects (YSOs), the compact H II region N 81 and a similar object within N 84, and two red supergiants (RSGs). We use the spectra to constrain the presence and temperature of cool dust and the excitation conditions within the neutral and ionized gas, in the circumstellar environments and interfaces with the surrounding interstellar medium. We compare these results with those obtained in the Large Magellanic Cloud (LMC). The spectra of the sources in N 81 (of which we also show the Infrared Space Observatory-Long-wavelength Spectrograph spectrum between 50 and 170 μm) and N 84 both display strong [O I] λ63 μm and [O III] λ88 μm fine-structure line emission. We attribute these lines to strong shocks and photo-ionized gas, respectively, in a "champagne flow" scenario. The nitrogen content of these two H II regions is very low, definitely N(N)/N(O) < 0.04 but possibly as low as N(N)/N(O) < 0.01. Overall, the oxygen lines and dust continuum are weaker in star-forming objects in the SMC than in the LMC. We attribute this to the lower metallicity of the SMC compared to that of the LMC. While the dust mass differs in proportion to metallicity, the oxygen mass differs less; both observations can be reconciled with higher densities inside star-forming cloud cores in the SMC than in the LMC. The dust in the YSOs in the SMC is warmer (37-51 K) than in comparable objects in the LMC (32-44 K). We attribute this to the reduced shielding and reduced cooling at the low metallicity of the SMC. On the other hand, the efficiency of the photo-electric effect to heat the gas is found to be indistinguishable to that measured in the same manner in the LMC, ≈0.1%-0.3%. This may result from higher cloud-core densities, or smaller grains, in the SMC. The dust associated with the two RSGs in our SMC sample is cool, and we argue that it is swept-up interstellar dust, or formed (or grew) within the bow-shock, rather than dust produced in these metal-poor RSGs themselves. Strong emission from crystalline water-ice is detected in at least one YSO. The spectra constitute a valuable resource for the planning and interpretation of observations with the Herschel Space Observatory and the Stratospheric Observatory For Infrared Astronomy.

Effects of Fluid Load on Human Urine Characteristics Related to Workplace Drug testing

DTIC Science & Technology

2012-03-01

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Comparison of Photoluminescence Imaging on Starting Multi-Crystalline Silicon Wafers to Finished Cell Performance: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, S.; Yan, F.; Dorn, D.

2012-06-01

Photoluminescence (PL) imaging techniques can be applied to multicrystalline silicon wafers throughout the manufacturing process. Both band-to-band PL and defect-band emissions, which are longer-wavelength emissions from sub-bandgap transitions, are used to characterize wafer quality and defect content on starting multicrystalline silicon wafers and neighboring wafers processed at each step through completion of finished cells. Both PL imaging techniques spatially highlight defect regions that represent dislocations and defect clusters. The relative intensities of these imaged defect regions change with processing. Band-to-band PL on wafers in the later steps of processing shows good correlation to cell quality and performance. The defect bandmore » images show regions that change relative intensity through processing, and better correlation to cell efficiency and reverse-bias breakdown is more evident at the starting wafer stage as opposed to later process steps. We show that thermal processing in the 200 degrees - 400 degrees C range causes impurities to diffuse to different defect regions, changing their relative defect band emissions.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Kai; Ma, Ying -Zhong; Simpson, Mary Jane

Charge carrier trapping degrades the performance of organometallic halide perovskite solar cells. To characterize the locations of electronic trap states in a heterogeneous photoactive layer, a spatially resolved approach is essential. Here, we report a comparative study on methylammonium lead tri-iodide perovskite thin films subject to different thermal annealing times using a combined photoluminescence (PL) and femtosecond transient absorption microscopy (TAM) approach to spatially map trap states. This approach coregisters the initially populated electronic excited states with the regions that recombine radiatively. Although the TAM images are relatively homogeneous for both samples, the corresponding PL images are highly structured. Themore » remarkable variation in the PL intensities as compared to transient absorption signal amplitude suggests spatially dependent PL quantum efficiency, indicative of trapping events. Furthermore, detailed analysis enables identification of two trapping regimes: a densely packed trapping region and a sparse trapping area that appear as unique spatial features in scaled PL maps.« less

Apollo 16 far-ultraviolet imagery and spectra of the Large Magellanic Cloud

NASA Technical Reports Server (NTRS)

Page, T.; Carruthers, G. R.

1976-01-01

The Large Magellanic Cloud was observed by the far ultraviolet camera spectrograph from the lunar surface during the Apollo 16 mission 22 April 1972. Images were obtained with about 3 arc min resolution, in the 1,050 to 1,600 and 1,250 to 1,600 A wavelength ranges, of nearly the entire LMC. Spectra were also obtained in the 1,050 to 1,600 and 900 to 1,600 A ranges along a strip 1/4 deg wide (determined by the instrument's grid collimator) passing across the LMC. The images and spectra have been scanned with a PDS microdensitometer, and isodensity contour plots have been prepared using the Univac 1108 computer.

Comparative analyses of industrial-scale human platelet lysate preparations.

PubMed

Pierce, Jan; Benedetti, Eric; Preslar, Amber; Jacobson, Pam; Jin, Ping; Stroncek, David F; Reems, Jo-Anna

2017-12-01

Efforts are underway to eliminate fetal bovine serum from mammalian cell cultures for clinical use. An emerging, viable replacement option for fetal bovine serum is human platelet lysate (PL) as either a plasma-based or serum-based product. Nine industrial-scale, serum-based PL manufacturing runs (i.e., lots) were performed, consisting of an average ± standard deviation volume of 24.6 ± 2.2 liters of pooled, platelet-rich plasma units that were obtained from apheresis donors. Manufactured lots were compared by evaluating various biochemical and functional test results. Comprehensive cytokine profiles of PL lots and product stability tests were performed. Global gene expression profiles of mesenchymal stromal cells (MSCs) cultured with plasma-based or serum-based PL were compared to MSCs cultured with fetal bovine serum. Electrolyte and protein levels were relatively consistent among all serum-based PL lots, with only slight variations in glucose and calcium levels. All nine lots were as good as or better than fetal bovine serum in expanding MSCs. Serum-based PL stored at -80°C remained stable over 2 years. Quantitative cytokine arrays showed similarities as well as dissimilarities in the proteins present in serum-based PL. Greater differences in MSC gene expression profiles were attributable to the starting cell source rather than with the use of either PL or fetal bovine serum as a culture supplement. Using a large-scale, standardized method, lot-to-lot variations were noted for industrial-scale preparations of serum-based PL products. However, all lots performed as well as or better than fetal bovine serum in supporting MSC growth. Together, these data indicate that off-the-shelf PL is a feasible substitute for fetal bovine serum in MSC cultures. © 2017 AABB.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machado, Thales R.; QIO-UJI, Universitat Jaume I, 12071 Castellón; Sczancoski, Júlio C.

Defect-related photoluminescence (PL) in materials have attracted interest for applications including near ultraviolet (NUV) excitable light-emitting diodes and in biomedical field. In this paper, hydroxyapatite [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}] nanorods with intense PL bands (bluish- and yellowish-white emissions) were obtained when excited under NUV radiation at room temperature. These nanoparticles were synthesized via chemical precipitation at 90 °C followed by distinct heat treatments temperatures (200–800 °C). Intense and broad emission profiles were achieved at 350 °C (380–750 nm) and 400 °C (380–800 nm). UV–Vis spectroscopy revealed band gap energies (5.58–5.78 eV) higher than the excitation energies (~3.54 and ~2.98more » eV at 350 and 415 nm, respectively), confirming the contribution of defect energy levels within the forbidden zone for PL emissions. The structural features were characterized by X-ray diffraction, Rietveld refinement, thermogravimetric analysis, and Fourier transform infrared spectroscopy. By means of these techniques, the relation between structural order-disorder induced by defects, chemical reactions at both lattice and surface of the materials as well as the PL, without activator centers, was discussed in details. - Graphical abstract: The self-activated photoluminescence emissions of chemically precipitated hydroxyapatite nanorods were improved by different heat treatment temperatures. - Highlights: • HA nanorods were synthesized with improved self-activated PL at room temperature. • PL profile and intensity dependents on the temperature of posterior heat treatments. • Bluish- and yellowish-white emissions under NUV excitation (350 and 415 nm). • Broad and intense profiles achieved at 350 °C (380–750 nm) and 400 °C (380–800 nm). • PL from the e′–h{sup •} recombination between defect energy levels within the band gap.« less

Exposing the Secrets of Two Well-Known Lactobacillus casei Phages, J-1 and PL-1, by Genomic and Structural Analysis

PubMed Central

Dieterle, Maria Eugenia; Bowman, Charles; Batthyany, Carlos; Lanzarotti, Esteban; Turjanski, Adrián; Hatfull, Graham

2014-01-01

Bacteriophage J-1 was isolated in 1965 from an abnormal fermentation of Yakult using Lactobacillus casei strain Shirota, and a related phage, PL-1, was subsequently recovered from a strain resistant to J-1. Complete genome sequencing shows that J-1 and PL-1 are almost identical, but PL-1 has a deletion of 1.9 kbp relative to J-1, resulting in the loss of four predicted gene products involved in immunity regulation. The structural proteins were identified by mass spectrometry analysis. Similarly to phage A2, two capsid proteins are generated by a translational frameshift and undergo proteolytic processing. The structure of gene product 16 (gp16), a putative tail protein, was modeled based on the crystal structure of baseplate distal tail proteins (Dit) that form the baseplate hub in other Siphoviridae. However, two regions of the C terminus of gp16 could not be modeled using this template. The first region accounts for the differences between J-1 and PL-1 gp16 and showed sequence similarity to carbohydrate-binding modules (CBMs). J-1 and PL-1 GFP-gp16 fusions bind specifically to Lactobacillus casei/paracasei cells, and the addition of l-rhamnose inhibits binding. J-1 gp16 exhibited a higher affinity than PL-1 gp16 for cell walls of L. casei ATCC 27139 in phage adsorption inhibition assays, in agreement with differential adsorption kinetics observed for both phages in this strain. The data presented here provide insights into how Lactobacillus phages interact with their hosts at the first steps of infection. PMID:25217012

Origin of stretched-exponential photoluminescence relaxation in size-separated silicon nanocrystals

DOE PAGES

Brown, Samuel L.; Krishnan, Retheesh; Elbaradei, Ahmed; ...

2017-05-25

A detailed understanding of the photoluminescence (PL) from silicon nanocrystals (SiNCs) is convoluted by the complexity of the decay mechanism, including a stretched-exponential relaxation and the presence of both nanosecond and microsecond time scales. In this publication, we analyze the microsecond PL decay of size-resolved SiNC fractions in both full-spectrum (FS) and spectrally resolved (SR) configurations, where the stretching exponent and lifetime are used to deduce a probability distribution function (PDF) of decay rates. For the PL decay measured at peak emission, we find a systematic shift and narrowing of the PDF in comparison to the FS measurements. In amore » similar fashion, we resolve the PL lifetime of the ‘blue’, ‘peak’, and ‘red’ regions of the spectrum and map PL decays of different photon energy onto their corresponding location in the PDF. Furthermore, a general trend is observed where higher and lower photon energies are correlated with shorter and longer lifetimes, respectively, which we relate to the PL line width and electron-phonon coupling.« less

Genome-wide association study of interferon-related cytopenia in chronic hepatitis C patients

PubMed Central

Thompson, Alexander J.; Clark, Paul J.; Singh, Abanish; Ge, Dongliang; Fellay, Jacques; Zhu, Mingfu; Zhu, Qianqian; Urban, Thomas J.; Patel, Keyur; Tillmann, Hans L.; Naggie, Susanna; Afdhal, Nezam H.; Jacobson, Ira M.; Esteban, Rafael; Poordad, Fred; Lawitz, Eric J.; McCone, Jonathan; Shiffman, Mitchell L.; Galler, Greg W.; King, John W.; Kwo, Paul Y.; Shianna, Kevin V.; Noviello, Stephanie; Pedicone, Lisa D.; Brass, Clifford A.; Albrecht, Janice K.; Sulkowski, Mark S.; Goldstein, David B.; McHutchison, John G.; Muir, Andrew J.

2012-01-01

Background & Aims Interferon-alfa (IFN)-related cytopenias are common and may be dose-limiting. We performed a genome wide association study on a well-characterized genotype 1 HCV cohort to identify genetic determinants of peginterferon-α (peg-IFN)-related thrombocytopenia, neutropenia, and leukopenia. Methods 1604/3070 patients in the IDEAL study consented to genetic testing. Trial inclusion criteria included a platelet (Pl) count ≥80 × 109/L and an absolute neutrophil count (ANC) ≥ 1500/mm3. Samples were genotyped using the Illumina Human610-quad BeadChip. The primary analyses focused on the genetic determinants of quantitative change in cell counts (Pl, ANC, lymphocytes, monocytes, eosinophils, and basophils) at week 4 in patients >80% adherent to therapy (n = 1294). Results 6 SNPs on chromosome 20 were positively associated with Pl reduction (top SNP rs965469, p = 10−10). These tag SNPs are in high linkage disequilibrium with 2 functional variants in the ITPA gene, rs1127354 and rs7270101, that cause ITPase deficiency and protect against ribavirin (RBV)-induced hemolytic anemia (HA). rs1127354 and rs7270101 showed strong independent associations with Pl reduction (p = 10−12, p = 10−7) and entirely explained the genome-wide significant associations. We believe this is an example of an indirect genetic association due to a reactive thrombocytosis to RBV-induced anemia: Hb decline was inversely correlated with Pl reduction (r = −0.28, p = 10−17) and Hb change largely attenuated the association between the ITPA variants and Pl reduction in regression models. No common genetic variants were associated with pegIFN-induced neutropenia or leucopenia. Conclusions Two ITPA variants were associated with thrombocytopenia; this was largely explained by a thrombocytotic response to RBV-induced HA attenuating IFN-related thrombocytopenia. No genetic determinants of pegIFN-induced neutropenia were identified. PMID:21703177

Sex allocation theory reveals a hidden cost of neonicotinoid exposure in a parasitoid wasp

PubMed Central

Whitehorn, Penelope R.; Cook, Nicola; Blackburn, Charlotte V.; Gill, Sophie M.; Green, Jade; Shuker, David M.

2015-01-01

Sex allocation theory has proved to be one the most successful theories in evolutionary ecology. However, its role in more applied aspects of ecology has been limited. Here we show how sex allocation theory helps uncover an otherwise hidden cost of neonicotinoid exposure in the parasitoid wasp Nasonia vitripennis. Female N. vitripennis allocate the sex of their offspring in line with Local Mate Competition (LMC) theory. Neonicotinoids are an economically important class of insecticides, but their deployment remains controversial, with evidence linking them to the decline of beneficial species. We demonstrate for the first time to our knowledge, that neonicotinoids disrupt the crucial reproductive behaviour of facultative sex allocation at sub-lethal, field-relevant doses in N. vitripennis. The quantitative predictions we can make from LMC theory show that females exposed to neonicotinoids are less able to allocate sex optimally and that this failure imposes a significant fitness cost. Our work highlights that understanding the ecological consequences of neonicotinoid deployment requires not just measures of mortality or even fecundity reduction among non-target species, but also measures that capture broader fitness costs, in this case offspring sex allocation. Our work also highlights new avenues for exploring how females obtain information when allocating sex under LMC. PMID:25925105

Yellow supergiants in open clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sowell, J.R.

1986-01-01

Superluminous giant stars (SLGs) have been reported in young globular clusters in the Large Magellanic Cloud (LMC). These stars appear to be in the post-asymptotic-giant-branch phase of evolution. This program was an investigation of galactic SLG candidates in open clusters, which are more like the LMC young globular clusters. These were chosen because luminosity, mass, and age determinations can be made for members since cluster distances and interstellar reddenings are known. Color magnitude diagrams were searched for candidates, using the same selection criteria as for SLGs in the LMC. Classification spectra were obtained of 115 program stars from McGraw-Hill Observatorymore » and of 68 stars from Cerro Tololo Inter-American Observatory Chile. These stars were visually classified on the MK system using spectral scans of standard stars taken at the respective observations. Published information was combined with this program's data for 83 stars in 30 clusters. Membership probabilities were assigned to these stars, and the clusters were analyzed according to age. It was seen that the intrinsically brightest supergiants are found in the youngest clusters. With increasing cluster age, the absolute luminosities attained by the supergiants decline. Also, it appears that the evolutionary tracks of luminosity class II stars are more similar to those of class I than of class III.« less

Network adaptation improves temporal representation of naturalistic stimuli in Drosophila eye: II mechanisms.

PubMed

Nikolaev, Anton; Zheng, Lei; Wardill, Trevor J; O'Kane, Cahir J; de Polavieja, Gonzalo G; Juusola, Mikko

2009-01-01

Retinal networks must adapt constantly to best present the ever changing visual world to the brain. Here we test the hypothesis that adaptation is a result of different mechanisms at several synaptic connections within the network. In a companion paper (Part I), we showed that adaptation in the photoreceptors (R1-R6) and large monopolar cells (LMC) of the Drosophila eye improves sensitivity to under-represented signals in seconds by enhancing both the amplitude and frequency distribution of LMCs' voltage responses to repeated naturalistic contrast series. In this paper, we show that such adaptation needs both the light-mediated conductance and feedback-mediated synaptic conductance. A faulty feedforward pathway in histamine receptor mutant flies speeds up the LMC output, mimicking extreme light adaptation. A faulty feedback pathway from L2 LMCs to photoreceptors slows down the LMC output, mimicking dark adaptation. These results underline the importance of network adaptation for efficient coding, and as a mechanism for selectively regulating the size and speed of signals in neurons. We suggest that concert action of many different mechanisms and neural connections are responsible for adaptation to visual stimuli. Further, our results demonstrate the need for detailed circuit reconstructions like that of the Drosophila lamina, to understand how networks process information.

The diffuse source at the center of LMC SNR 0509–67.5 is a background galaxy at z = 0.031

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pagnotta, Ashley; Walker, Emma S.; Schaefer, Bradley E., E-mail: pagnotta@amnh.org

2014-06-20

Type Ia supernovae (SNe Ia) are well-known for their use in the measurement of cosmological distances, but our continuing lack of concrete knowledge about their progenitor stars is both a matter of debate and a source of systematic error. In our attempts to answer this question, we presented unambiguous evidence that LMC SNR 0509–67.5, the remnant of an SN Ia that exploded in the Large Magellanic Cloud 400 ± 50 yr ago, did not have any point sources (stars) near the site of the original supernova explosion, from which we concluded that this particular supernova must have had a progenitormore » system consisting of two white dwarfs. There is, however, evidence of nebulosity near the center of the remnant, which could have been left over detritus from the less massive WD, or could have been a background galaxy unrelated to the supernova explosion. We obtained long-slit spectra of the central nebulous region using GMOS on Gemini South to determine which of these two possibilities is correct. The spectra show Hα emission at a redshift of z = 0.031, which implies that the nebulosity in the center of LMC SNR 0509–67.5 is a background galaxy, unrelated to the supernova.« less

Mid-infrared Integrated-light Photometry Of LMC Star Clusters

NASA Astrophysics Data System (ADS)

Pessev, Peter; Goudfrooij, P.; Puzia, T.; Chandar, R.

2008-03-01

Massive star clusters (Galactic Globular Clusters and Populous Clusters in the Magellanic Clouds) are the best available approximation of Simple Stellar Populations (SSPs). Since the stellar populations in these nearby objects are studied in details, they provide fundamental age/metallicity templates for interpretation of the galaxy properties, testing and calibration of the SSP Models. Magellanic Cloud clusters are particularly important since they populate a region of the age/metallicity parameter space that is not easily accessible in our Galaxy. We present the first Mid-IR integrated-light measurements for six LMC clusters based on our Spitzer IRAC imaging program. Since we are targeting a specific group of intermediate-age clusters, our imaging goes deeper compared to SAGE-LMC survey data. We present a literature compilation of clusters' properties along with multi-wavelength integrated light photometry database spanning from the optical (Johnson U band) to the Mid-IR (IRAC Channel 4). This data provides an important empirical baseline for the interpretation of galaxy colors in the Mid-IR (especially high-z objects whose integrated-light is dominated by TP-AGB stars emission). It is also a valuable tool to check the SSP model predictions in the intermediate-age regime and provides calibration data for the next generation of SSP models.

Sage Studies Of The Mass Return From AGB And RSG Stars In The Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Sargent, Benjamin A.; Srinivasan, S.; Meixner, M.

2011-01-01

The Surveying the Agents of a Galaxy's Evolution (SAGE; PI: M. Meixner) Spitzer Space Telescope Legacy project aims to further our understanding of the life cycle of matter in galaxies by studying this life cycle in our neighboring galaxy, the Large Magellanic Cloud (LMC). Combining SAGE mid-infrared photometry with that at shorter wavelengths from other catalogs, the spectral energy distribution (SED) for each of >25000 Asymptotic Giant Branch (AGB) and Red Supergiant (RSG) stars in the LMC has been assembled. To model mass loss from these stars, my colleagues and I have constructed the grid of RSG and AGB models (GRAMS) using the radiative transfer code 2Dust. I will discuss how GRAMS was constructed, and how we use it to determine the mass-loss rate for each evolved star studied, which gives the total mass-loss return to the LMC from AGB and RSG stars. In my talk, I show how this total mass-loss return is divided into oxygen-rich (O-rich) and carbon-rich (C-rich) dust using SED-fitting to identify O-rich versus C-rich AGB stars. Applications of this work to determining the mass return from evolved stars in other galaxies, including the Milky Way, will also be discussed.

Application of a relativistic accretion disc model to X-ray spectra of LMC X-1 and GRO J1655-40

NASA Astrophysics Data System (ADS)

Gierliński, Marek; Maciołek-Niedźwiecki, Andrzej; Ebisawa, Ken

2001-08-01

We present a general relativistic accretion disc model and its application to the soft-state X-ray spectra of black hole binaries. The model assumes a flat, optically thick disc around a rotating Kerr black hole. The disc locally radiates away the dissipated energy as a blackbody. Special and general relativistic effects influencing photons emitted by the disc are taken into account. The emerging spectrum, as seen by a distant observer, is parametrized by the black hole mass and spin, the accretion rate, the disc inclination angle and the inner disc radius. We fit the ASCA soft-state X-ray spectra of LMC X-1 and GRO J1655-40 by this model. We find that, having additional limits on the black hole mass and inclination angle from optical/UV observations, we can constrain the black hole spin from X-ray data. In LMC X-1 the constraint is weak, and we can only rule out the maximally rotating black hole. In GRO J1655-40 we can limit the spin much better, and we find 0.68<=a<=0.88. Accretion discs in both sources are radiation-pressure dominated. We do not find Compton reflection features in the spectra of any of these objects.

Prefrontal neurons encode context-based response execution and inhibition in reward seeking and extinction

PubMed Central

Moorman, David E.; Aston-Jones, Gary

2015-01-01

The prefrontal cortex (PFC) guides execution and inhibition of behavior based on contextual demands. In rodents, the dorsal/prelimbic (PL) medial PFC (mPFC) is frequently considered essential for execution of goal-directed behavior (“go”) whereas ventral/infralimbic (IL) mPFC is thought to control behavioral suppression (“stop”). This dichotomy is commonly seen for fear-related behaviors, and for some behaviors related to cocaine seeking. Overall, however, data for reward-directed behaviors are ambiguous, and few recordings of PL/IL activity have been performed to demonstrate single-neuron correlates. We recorded neuronal activity in PL and IL during discriminative stimulus driven sucrose seeking followed by multiple days of extinction of the reward-predicting stimulus. Contrary to a generalized PL-go/IL-stop hypothesis, we found cue-evoked activity in PL and IL during reward seeking and extinction. Upon analyzing this activity based on resultant behavior (lever press or withhold), we found that neurons in both areas encoded contextually appropriate behavioral initiation (during reward seeking) and withholding (during extinction), where context was dictated by response–outcome contingencies. Our results demonstrate that PL and IL signal contextual information for regulation of behavior, irrespective of whether that involves initiation or suppression of behavioral responses, rather than topographically encoding go vs. stop behaviors. The use of context to optimize behavior likely plays an important role in maximizing utility-promoting exertion of activity when behaviors are rewarded and conservation of energy when not. PMID:26170333

The EPOCH Project. I. Periodic variable stars in the EROS-2 LMC database

NASA Astrophysics Data System (ADS)

Kim, Dae-Won; Protopapas, Pavlos; Bailer-Jones, Coryn A. L.; Byun, Yong-Ik; Chang, Seo-Won; Marquette, Jean-Baptiste; Shin, Min-Su

2014-06-01

The EPOCH (EROS-2 periodic variable star classification using machine learning) project aims to detect periodic variable stars in the EROS-2 light curve database. In this paper, we present the first result of the classification of periodic variable stars in the EROS-2 LMC database. To classify these variables, we first built a training set by compiling known variables in the Large Magellanic Cloud area from the OGLE and MACHO surveys. We crossmatched these variables with the EROS-2 sources and extracted 22 variability features from 28 392 light curves of the corresponding EROS-2 sources. We then used the random forest method to classify the EROS-2 sources in the training set. We designed the model to separate not only δ Scuti stars, RR Lyraes, Cepheids, eclipsing binaries, and long-period variables, the superclasses, but also their subclasses, such as RRab, RRc, RRd, and RRe for RR Lyraes, and similarly for the other variable types. The model trained using only the superclasses shows 99% recall and precision, while the model trained on all subclasses shows 87% recall and precision. We applied the trained model to the entire EROS-2 LMC database, which contains about 29 million sources, and found 117 234 periodic variable candidates. Out of these 117 234 periodic variables, 55 285 have not been discovered by either OGLE or MACHO variability studies. This set comprises 1906 δ Scuti stars, 6607 RR Lyraes, 638 Cepheids, 178 Type II Cepheids, 34 562 eclipsing binaries, and 11 394 long-period variables. catalog of these EROS-2 LMC periodic variable stars is available at http://stardb.yonsei.ac.kr and at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/566/A43

Hitomi observations of the LMC SNR N 132 D: Highly redshifted X-ray emission from iron ejecta

NASA Astrophysics Data System (ADS)

Hitomi Collaboration; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steven W.; Angelini, Lorella; Audard, Marc; Awaki, Hisamitsu; Axelsson, Magnus; Bamba, Aya; Bautz, Marshall W.; Blandford, Roger; Brenneman, Laura W.; Brown, Gregory V.; Bulbul, Esra; Cackett, Edward M.; Chernyakova, Maria; Chiao, Meng P.; Coppi, Paolo S.; Costantini, Elisa; de Plaa, Jelle; de Vries, Cor P.; den Herder, Jan-Willem; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan E.; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew C.; Ferrigno, Carlo; Foster, Adam R.; Fujimoto, Ryuichi; Fukazawa, Yasushi; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi C.; Gandhi, Poshak; Giustini, Margherita; Goldwurm, Andrea; Gu, Liyi; Guainazzi, Matteo; Haba, Yoshito; Hagino, Kouichi; Hamaguchi, Kenji; Harrus, Ilana M.; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko S.; Hornschemeier, Ann; Hoshino, Akio; Hughes, John P.; Ichinohe, Yuto; Iizuka, Ryo; Inoue, Hajime; Inoue, Yoshiyuki; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Iwai, Masachika; Kaastra, Jelle; Kallman, Tim; Kamae, Tsuneyoshi; Kataoka, Jun; Katsuda, Satoru; Kawai, Nobuyuki; Kelley, Richard L.; Kilbourne, Caroline A.; Kitaguchi, Takao; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Koyama, Katsuji; Koyama, Shu; Kretschmar, Peter; Krimm, Hans A.; Kubota, Aya; Kunieda, Hideyo; Laurent, Philippe; Lee, Shiu-Hang; Leutenegger, Maurice A.; Limousin, Olivier; Loewenstein, Michael; Long, Knox S.; Lumb, David; Madejski, Greg; Maeda, Yoshitomo; Maier, Daniel; Makishima, Kazuo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian R.; Mehdipour, Missagh; Miller, Eric D.; Miller, Jon M.; Mineshige, Shin; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Mukai, Koji; Murakami, Hiroshi; Mushotzky, Richard F.; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakashima, Shinya; Nakazawa, Kazuhiro; Nobukawa, Kumiko K.; Nobukawa, Masayoshi; Noda, Hirofumi; Odaka, Hirokazu; Ohashi, Takaya; Ohno, Masanori; Okajima, Takashi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stéphane; Petre, Robert; Pinto, Ciro; Porter, Frederick S.; Pottschmidt, Katja; Reynolds, Christopher S.; Safi-Harb, Samar; Saito, Shinya; Sakai, Kazuhiro; Sasaki, Toru; Sato, Goro; Sato, Kosuke; Sato, Rie; Sato, Toshiki; Sawada, Makoto; Schartel, Norbert; Serlemtsos, Peter J.; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall K.; Soong, Yang; Stawarz, Łukasz; Sugawara, Yasuharu; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Takayuki; Tanaka, Takaaki; Tanaka, Yasuo; Tanaka, Yasuyuki T.; Tashiro, Makoto S.; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi Go; Uchida, Hiroyuki; Uchiyama, Hideki; Uchiyama, Yasunobu; Ueda, Shutaro; Ueda, Yoshihiro; Uno, Shin'ichiro; Urry, C. Megan; Ursino, Eugenio; Watanabe, Shin; Werner, Norbert; Wilkins, Dan R.; Williams, Brian J.; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko Y.; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yatsu, Yoichi; Yonetoku, Daisuke; Zhuravleva, Irina; Zoghbi, Abderahmen

2018-03-01

We present Hitomi observations of N 132 D, a young, X-ray bright, O-rich core-collapse supernova remnant in the Large Magellanic Cloud (LMC). Despite a very short observation of only 3.7 ks, the Soft X-ray Spectrometer (SXS) easily detects the line complexes of highly ionized S K and Fe K with 16-17 counts in each. The Fe feature is measured for the first time at high spectral resolution. Based on the plausible assumption that the Fe K emission is dominated by He-like ions, we find that the material responsible for this Fe emission is highly redshifted at ˜ 800 km s-1 compared to the local LMC interstellar medium (ISM), with a 90% credible interval of 50-1500 km s-1 if a weakly informative prior is placed on possible line broadening. This indicates (1) that the Fe emission arises from the supernova ejecta, and (2) that these ejecta are highly asymmetric, since no blueshifted component is found. The S K velocity is consistent with the local LMC ISM, and is likely from swept-up ISM material. These results are consistent with spatial mapping that shows the He-like Fe concentrated in the interior of the remnant and the S tracing the outer shell. The results also show that even with a very small number of counts, direct velocity measurements from Doppler-shifted lines detected in extended objects like supernova remnants are now possible. Thanks to the very low SXS background of ˜ 1 event per spectral resolution element per 100 ks, such results are obtainable during short pointed or slew observations with similar instruments. This highlights the power of high-spectral-resolution imaging observations, and demonstrates the new window that has been opened with Hitomi and will be greatly widened with future missions such as the X-ray Astronomy Recovery Mission (XARM) and Athena.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chandar, Rupali; Fall, S. Michael; Whitmore, Bradley C., E-mail: Rupali.Chandar@utoledo.ed, E-mail: fall@stsci.ed, E-mail: whitmore@stsci.ed

We compare the observed bivariate distribution of masses (M) and ages (tau) of star clusters in the Large Magellanic Cloud (LMC) with the predicted distributions g(M, tau) from three idealized models for the disruption of star clusters: (1) sudden mass-dependent disruption, (2) gradual mass-dependent disruption, and (3) gradual mass-independent disruption. The model with mass-independent disruption provides a good, first-order description of these cluster populations, with g(M, tau) {proportional_to} M {sup beta}tau{sup g}amma, beta = -1.8 +- 0.2 and gamma = -0.8 +- 0.2, at least for clusters with ages tau {approx}< 10{sup 9} yr and masses M {approx}> 10{sup 3}more » M{sub sun} (more specifically, tau {approx}< 10{sup 7}(M/10{sup 2} M{sub sun}){sup 1.3} yr). This model predicts that the clusters should have a power-law luminosity function, dN/dL {proportional_to} L {sup -1.8}, in agreement with observations. The first two models, on the other hand, fare poorly when describing the observations, refuting previous claims that mass-dependent disruption of star clusters is observed in the LMC over the studied M-tau domain. Clusters in the SMC can be described by the same g(M, tau) distribution as for the LMC, but with smaller samples and hence larger uncertainties. The successful g(M, tau) model for clusters in the Magellanic Clouds is virtually the same as the one for clusters in the merging Antennae galaxies, but extends the domain of validity to lower masses and to older ages. This indicates that the dominant disruption processes are similar in these very different galaxies over at least tau {approx}< 10{sup 8} yr and possibly tau {approx}< 10{sup 9} yr. The mass functions for young clusters in the LMC are power laws, while that for ancient globular clusters is peaked. We show that the observed shapes of these mass functions are consistent with expectations from the simple evaporation model presented by McLaughlin and Fall.« less

Design, Development, and Integration of A Space Shuttle Orbiter Bay 13 Payload Carrier

NASA Technical Reports Server (NTRS)

Spencer, Susan H.; Phillips, Michael W.; Upton, Lanny (Technical Monitor)

2002-01-01

Bay 13 of the Space Shuttle Orbiter has been limited to small sidewall mounted payloads and ballast. In order to efficiently utilize this space, a concept was developed for a cross-bay cargo carrier to mount Orbital Replacement Units (ORU's) for delivery to the International Space Station and provide additional opportunities for science payloads, while meeting the Orbiter ballast requirements. The Lightweight Multi-Purpose Experiment Support Structure (MPESS) Carrie (LMC) was developed and tested by NASA's Marshall Space Flight Center and the Boeing Company. The Multi-Purpose Experiment Support Structure (MPESS), which was developed for the Spacelab program was modified, removing the keel structure and relocating the sill trunnions to fit in Bay 13. Without the keel fitting, the LMC required a new and innovative concept for transferring Y loads into the Orbiter structure. Since there is no keel fitting available in the Bay 13 location, the design had to utilize the longeron bridge T-rail to distribute the Y loads. This concept has not previously been used in designing Shuttle payloads. A concept was developed to protect for Launch-On-Need ORU's, while providing opportunities for science payloads. Categories of potential ORU's were defined, and Get-Away Special (GAS) payloads of similar mass properties were provided by NASA's Goddard Space Flight Center. Four GAS payloads were manifest as the baseline configuration, preserving the capability to swap up to two ORU's for the corresponding science payloads, after installation into the Orbiter cargo bay at the pad, prior to closeout. Multiple configurations were considered for the analytical integration, to protect for all defined combinations of ORU's and GAS payloads. The first physical integration of the LMC war performed by Goddard Space Flight Center and Kennedy Space Center at an off-line facility at Kennedy Space Center. This paper will discuss the design challenges, structural testing, analytical and physical integration for the LMC's successful maiden flight on STS-108/ISS UF-1 mission in December 2001.

Geometry of the Large Magellanic Cloud Using Multi- wavelength Photometry of Classical Cepheids

NASA Astrophysics Data System (ADS)

Deb, Sukanta; Ngeow, Chow-Choong; Kanbur, Shashi M.; Singh, Harinder P.; Wysocki, Daniel; Kumar, Subhash

2018-05-01

We determine the geometrical and viewing angle parameters of the Large Magellanic Cloud (LMC) using the Leavitt law based on a sample of more than 3500 common classical Cepheids (FU and FO) in optical (V, I), near-infrared (JHKs) and mid-infrared ([3.6] μm and [4.5] μm) photometric bands. Statistical reddening and distance modulus free from the effect of reddening to each of the individual Cepheids are obtained using the simultaneous multi-band fit to the apparent distance moduli from the analysis of the resulting Leavitt laws in these seven photometric bands. A reddening map of the LMC obtained from the analysis shows good agreement with the other maps available in the literature. Extinction free distance measurements along with the information of the equatorial coordinates (α, δ) for individual stars are used to obtain the corresponding Cartesian coordinates with respect to the plane of the sky. By fitting a plane solution of the form z = f(x, y) to the observed three dimensional distribution, the following viewing angle parameters of the LMC are obtained: inclination angle i = 25°.110 ± 0°.365, position angle of line of nodes θlon = 154°.702 ± 1°.378. On the other hand, modelling the observed three dimensional distribution of the Cepheids as a triaxial ellipsoid, the following values of the geometrical axes ratios of the LMC are obtained: 1.000 ± 0.003: 1.151 ± 0.003: 1.890 ± 0.014 with the viewing angle parameters: inclination angle of i = 11°.920 ± 0°.315 with respect to the longest axis from the line of sight and position angle of line of nodes θlon = 128°.871 ± 0°.569. The position angles are measured eastwards from north.

Optical properties of nearly lattice-matched GaN/(Al,In)N quantum wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liaugaudas, Gediminas; Jacopin, Gwénolé; Carlin, Jean-François

2016-05-28

We report a systematic study of the photoluminescence (PL) properties of a series of nearly lattice-matched (LM) GaN/(Al,In)N single quantum well (SQW) samples, with well thickness ranging from 1.5 to 5 nm, grown by metalorganic vapor phase epitaxy. Temperature dependent PL and time-resolved PL measurements reveal similar trends among the studied SQW samples, which also indicate strong localization effects. The observed PL energy behavior, akin to the S-shape, accompanied first by a narrowing and then a broadening of the PL line width with increasing temperature, closely resemble previous observations made on the more established (In,Ga)N/GaN QW system. The similar trends observedmore » in the PL features of those two QW systems imply that the PL properties of LM GaN/(Al,In)N SQW samples are also governed by localized states. The effects of carrier transfer among these localization sites are clearly observed for the 3 nm thick QW, evidenced by an increasing PL intensity in the lower energy spectral window and a concomitant increase in the corresponding PL decay time. Time-resolved data corroborate the picture of strongly localized carriers and also indicate that above a well thickness dependent delocalization temperature carrier distribution across the localized sites reaches thermal equilibrium, as the PL decay times over different spectral regions converge to the same value. Based on the difference between the calculated QW ground state transition energy, obtained using the envelope wave function formalism, and the measured PL energy, a localization energy of at least a few hundreds of meV has been extracted for all of the studied SQW samples. This rather large value also implies that In-related localization effects are more pronounced in the GaN/(Al,In)N system with respect to those in the (In,Ga)N/GaN one for a similar In content.« less

Synergistic suppression of human breast cancer cells by combination of plumbagin and zoledronic acid In vitro.

PubMed

Qiao, Han; Wang, Ting-yu; Yan, Wei; Qin, An; Fan, Qi-ming; Han, Xiu-guo; Wang, Yu-gang; Tang, Ting-ting

2015-09-01

Zoledronic acid (ZA), a bisphosphonate, is currently used in combination with chemotherapeutic agents to suppress breast cancer cell proliferation or breast cancer-induced osteolysis. The aim of this study was to investigate the effects of ZA combined with a natural anticancer compound plumbagin (PL) against human breast cancer cells in vitro. Human breast cancer MDA-MB-231SArfp cells were treated with ZA, PL or a combination of ZA and PL. The cell growth, apoptosis and migration were evaluated using CCK-8 assay, flow cytometry and transwell assay, respectively. The expression of apoptosis-related proteins was measured using real-time PCR and Western blotting. Synergism was evaluated using Compusyn software, and the combination index (CI) and drug reduction index (DRI) values were determined. PL or ZA alone caused mild cytotoxicity (the IC50 value at 24 h was 12.18 and above 100 μmol/L, respectively). However, the combination of ZA and PL caused a synergistic cytotoxicity (CI=0.26). The DRI values also showed a synergistic effect between PL and ZA, with actual values of 5.52 and 3.59, respectively. Furthermore, PL and ZA synergistically induced apoptosis and inhibited migration of the breast cancer cells. Moreover, the combination of ZA and PL decreased the expression of Notch-1, cleaved PARP, Bcl-2 and Bcl-xl, and increased the expression of cleaved caspase-3, CDKN1A and ID1. When the breast cancer cells were transfected with specific siRNA against Notch-1, the combination of ZA and PL markedly increased the expression of Bcl-2. Combination of ZA and PL synergistically suppresses human breast cancer MDA-MB-231SArfp cells in vitro. PL can inhibit ZA-induced activation of the Notch-1 signaling pathway and subsequently reduce the expression of Bcl-2, thus potentiating cancer cell apoptosis.

Antibacterial activity and mechanism of action of ε-poly-L-lysine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Ruosong; Xu, Hengyi; Wan, Cuixiang

Highlights: •Antibacterial activity and mechanism of ε-PL against E. coli O157:H7 was investigated. •Critical inhibitory factors toward the growth of E. coli O157:H7 by ε-PL was analyzed. •Cell membrane integrity and cell morphology of E. coli O157:H7 was affected by ε-PL. •A positive correlation between reactive oxygen species levels and ε-PL concentration in E. coli O157:H7 cells. •ε-PL induced the expression of different genes related to oxidative/redox stress, SOS response, virulence. -- Abstract: ε-Poly-L-lysine (ε-PL) is widely used as an antibacterial agent because of its broad antimicrobial spectrum. However, the mechanism of ε-PL against pathogens at the molecular level hasmore » not been elucidated. This study investigated the antibacterial activity and mechanism of ε-PL against Escherichia coli O157:H7 CMCC44828. Propidium monoazide-PCR test results indicated that the threshold condition of ε-PL for complete membrane lysis of E. coli O157:H7 was 10 μg/mL (90% mortality for 5 μg/mL). Further verification of the destructive effect of ε-PL on cell structure was performed by atomic force microscopy and transmission electron microscopy. Results showed a positive correlation between reactive oxygen species (ROS) levels and ε-PL concentration in E. coli O157:H7 cells. Moreover, the mortality of E. coli O157:H7 was reduced when antioxidant N-acetylcysteine was added. Results from real-time quantitative PCR (RT-qPCR) indicated that the expression levels of oxidative stress genes sodA and oxyR were up-regulated 4- and 16-fold, respectively, whereas virulence genes eaeA and espA were down-regulated after ε-PL treatment. Expression of DNA damage response (SOS response) regulon genes recA and lexA were also affected by ε-PL. In conclusion, the antibacterial mechanism of ε-PL against E. coli O157:H7 may be attributed to disturbance on membrane integrity, oxidative stress by ROS, and effects on various gene expressions, such as regulation of oxidative stress, SOS response, and changes in virulence.« less

Visible photoluminescence from plasma-polymerized-organosilicone thin films deposited from HMDSO/O2 induced remote plasma: effect of oxygen fraction

NASA Astrophysics Data System (ADS)

Naddaf, M.; Saloum, S.

2008-09-01

Visible photoluminescence (PL) from thin films deposited on silicon wafers by remote plasma polymerization of the hexamethyledisiloxane (HMDSO)/O2 mixture in a radio-frequency hollow cathode discharge reactor has been investigated as a function of different oxygen fractions ( \\chi _{O_2 } =0 , 0.38, 0.61, 0.76 and 0.9). At room temperature, the film deposited at \\chi _{O_2 } =0 exhibits a strong, broad PL band peak centred at around 537.6 nm. A blue shift and a considerable decrease (~one order) in the intensity of the PL peak are observed after the addition of oxygen. Furthermore, in contrast to the film deposited from pure HMDSO, the low temperature (15 K) PL spectra of the film deposited from different HMDSO/O2 mixtures exhibit two separated 'green-blue' and 'yellow-green' PL peaks. The PL behaviour of the deposited films is correlated with their structural and morphological properties, investigated by using Fourier transform infrared, atomic force microscope and contact angle techniques. In addition, it is found from spectrophotometry measurements that the deposited films have relatively low absorption coefficients (in the range 100-500 cm-1) in the spectral range of their PL emission, attractive for possible integrated optics devices.

Photoluminescence properties of anodic aluminum oxide formed in a mixture of ammonium fluoride and oxalic acid

NASA Astrophysics Data System (ADS)

Li, Shou-Yi; Wang, Jian; Li, Yan

2017-06-01

Highly ordered anodic aluminum oxide (AAO) membranes are fabricated electrochemically in an electrolyte mixture with various concentrations of C2H2O4 or NH4F. Photoluminescence (PL) properties of AAO membranes have been investigated before and after annealing in the range from 300°C to 650°C. X-ray diffraction reveals the amorphous nature of AAO membranes. Energy dispersive spectroscopy indicates the presence of fluorine species incorporated in oxide membranes during the anodizing. PL measurements show a strong PL band in the wavelength range of 350 to 550 nm. With the increase of the concentration of the NH4F or C2H2O4 in the electrolyte mixture, the peak positions of the PL bands have a blueshift or redshift and the intensities have a maximum value. As indicated by the PL excitation spectra, there are two excitation peaks of 285 and 330 nm, which can account for the PL emission band. We have proposed that the PL originates from optical transitions in two kinds of centers that are related to oxygen vacancies, F+ (285 nm) and F (330 nm). This work is not only beneficial to further understanding of the light-emitting property of AAO membranes but also enlarges the application scope.

Chemical Evolution and History of Star Formation in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Gustafsson, Bengt

1995-07-01

Large scale processes controlling star formation and nucleosynthesis are fundamental but poorly understood. This is especially true for external galaxies. A detailed study of individual main sequence stars in the LMC Bar is proposed. The LMC is close enough to allow this, has considerable spread in stellar ages and a structure permitting identification of stellar populations and their structural features. The Bar presumably plays a dominant role in the chemical and dynamical evolution of the galaxy. Our knowledge is, at best, based on educated guesses. Still, the major population of the Bar is quite old, and many member stars are relatively evolved. The Bar seems to contain stars similar to those of Intermediate to Extreme Pop II in the Galaxy. We want to study the history of star formation, chemical evolution and initial mass function of the population dominating the Bar. We will use field stars close to the turn off point in the HR diagram. From earlier studies, we know that 250-500 such stars are available for uvby photometry in the PC field. We aim at an accuracy of 0.1 -0.2 dex in Me/H and 25% or better in relative ages. This requires an accuracy of about 0.02 mag in the uvby indices, which can be reached, taking into account errors in calibration, flat fielding, guiding and problems due to crowding. For a study of the luminosity function fainter stars will be included as well. Calibration fields are available in Omega Cen and M 67.

Precision Landing and Hazard Avoidance Doman

NASA Technical Reports Server (NTRS)

Robertson, Edward A.; Carson, John M., III

2016-01-01

The Precision Landing and Hazard Avoidance (PL&HA) domain addresses the development, integration, testing, and spaceflight infusion of sensing, processing, and GN&C functions critical to the success and safety of future human and robotic exploration missions. PL&HA sensors also have applications to other mission events, such as rendezvous and docking. Autonomous PL&HA builds upon the core GN&C capabilities developed to enable soft, controlled landings on the Moon, Mars, and other solar system bodies. Through the addition of a Terrain Relative Navigation (TRN) function, precision landing within tens of meters of a map-based target is possible. The addition of a 3-D terrain mapping lidar sensor improves the probability of a safe landing via autonomous, real-time Hazard Detection and Avoidance (HDA). PL&HA significantly improves the probability of mission success and enhances access to sites of scientific interest located in challenging terrain. PL&HA can also utilize external navigation aids, such as navigation satellites and surface beacons. Advanced Lidar Sensors High precision ranging, velocimetry, and 3-D terrain mapping Terrain Relative Navigation (TRN) TRN compares onboard reconnaissance data with real-time terrain imaging data to update the S/C position estimate Hazard Detection and Avoidance (HDA) Generates a high-resolution, 3-D terrain map in real-time during the approach trajectory to identify safe landing targets Inertial Navigation During Terminal Descent High precision surface relative sensors enable accurate inertial navigation during terminal descent and a tightly controlled touchdown within meters of the selected safe landing target.

Sustained conditioned responses in prelimbic prefrontal neurons are correlated with fear expression and extinction failure.

PubMed

Burgos-Robles, Anthony; Vidal-Gonzalez, Ivan; Quirk, Gregory J

2009-07-01

During auditory fear conditioning, it is well established that lateral amygdala (LA) neurons potentiate their response to the tone conditioned stimulus, and that this potentiation is required for conditioned fear behavior. Conditioned tone responses in LA, however, last only a few hundred milliseconds and cannot be responsible for sustained fear responses to a tone lasting tens of seconds. Recent evidence from inactivation and stimulation studies suggests that the prelimbic (PL) prefrontal cortex is necessary for expression of learned fears, but the timing of PL tone responses and correlations with fear behavior have not been studied. Using multichannel unit recording techniques in behaving rats, we observed sustained conditioned tone responses in PL that were correlated with freezing behavior on a second-to-second basis during the presentation of a 30 s tone. PL tone responses were also correlated with conditioned freezing across different experimental phases (habituation, conditioning, extinction). Moreover, the persistence of PL responses after extinction training was associated with failure to express extinction memory. Together with previous inactivation findings, the present results suggest that PL transforms transient amygdala inputs to a sustained output that drives conditioned fear responses and gates the expression of extinction. Given the relatively long latency of conditioned responses we observed in PL (approximately 100 ms after tone onset), we propose that PL integrates inputs from the amygdala, hippocampus, and other cortical sources to regulate the expression of fear memories.

50-500 MeV observations of LMC supernova 1987A

NASA Astrophysics Data System (ADS)

Summer, T. J.; Rochester, G. K.; Sood, R. K.; Thomas, J.; Waldron, L.; Manchanda, R. K.; Frye, G.; Jenkins, T.; Koga, R.; Staubert, R.; Kendziorra, E.; Ubertini, P.; Bazzano, A.; La Padula, C.

Since the discovery of the supernova outburst in the LMC in 1987, two attempts (on day 55 and day 407) have been made to measure the high energy gamma-ray flux in the range 50-500 MeV, by using a balloon-borne spark chamber telescope. On day 55, no positive signal was seen from the source. A 3 sigma upper limit of 2.9 x 10 to the -5th ph/sq cm s was obtained after the analysis of the spark chamber data. Preliminary analysis of the quick look data obtained in the second flight shows that the gamma-ray flux even on day 407 was less than 9 x 10 to the -4th ph/sq cm s (3 sigma).

REVIEWS OF TOPICAL PROBLEMS: Gravitational microlensing

NASA Astrophysics Data System (ADS)

Zakharov, Aleksandr F.; Sazhin, Mikhail V.

1998-10-01

The foundations of standard microlensing theory are discussed as applied to stars in the Galactic bulge, Magellanic Clouds or other nearby galaxies and gravitational microlenses assumed to lie in-between these stars and the terrestrial observer. In contrast to the review article by Gurevich et al. [48], microlensing by compact objects is mainly considered. Criteria for the identification of microlensing events are discussed as also are microlensing events not satisfying these criteria, such as non-symmetrical light curves and chromatic and polarization effects. The Large Magellanic Cloud (LMC) and Galactic bulge microlensing data of the MACHO group are discussed in detail and also the LMC data of EROS and the Galactic bulge data of OGLE are presented. A detailed comparison of theoretical predictions and observations is given.

The Tip of the Red Giant Branch Distances to Type Ia Supernova Host Galaxies. IV. Color Dependence and Zero-point Calibration

NASA Astrophysics Data System (ADS)

Jang, In Sung; Lee, Myung Gyoon

2017-01-01

We present a revised Tip of the Red Giant Branch (TRGB) calibration, accurate to 2.7% of distance. A modified TRGB magnitude corrected for its color dependence, the QT magnitude, is introduced for better measurement of the TRGB. We determine the color-magnitude relation of the TRGB from photometry of deep images of HST/ACS fields around eight nearby galaxies. The zero-point of the TRGB at the fiducial metallicity ([Fe/H] = -1.6 ({(V-I)}0,{TRGB}=1.5)) is obtained from photometry of two distance anchors, NGC 4258 (M106) and the Large Magellanic Cloud (LMC), to which precise geometric distances are known: MQT,TRGB = -4.023 ± 0.073 mag from NGC 4258 and MQT,TRGB = -4.004 ± 0.096 mag from the LMC. A weighted mean of the two zero-points is MQT,TRGB = -4.016 ± 0.058 mag. Quoted uncertainty is ˜2× smaller than those of previous calibrations. We compare the empirical TRGB calibration derived in this study with theoretical stellar models, finding that there are significant discrepancies, especially for red color ({({{F}}606{{W}}-{{F}}814{{W}})}0≳ 2.5). We provide the revised TRGB calibration in several magnitude systems for future studies.

Determination of the electron-capture coefficients and the concentration of free electrons in GaN from time-resolved photoluminescence

PubMed Central

Reshchikov, M. A.; McNamara, J. D.; Toporkov, M.; Avrutin, V.; Morkoç, H.; Usikov, A.; Helava, H.; Makarov, Yu.

2016-01-01

Point defects in high-purity GaN layers grown by hydride vapor phase epitaxy are studied by steady-state and time-resolved photoluminescence (PL). The electron-capture coefficients for defects responsible for the dominant defect-related PL bands in this material are found. The capture coefficients for all the defects, except for the green luminescence (GL1) band, are independent of temperature. The electron-capture coefficient for the GL1 band significantly changes with temperature because the GL1 band is caused by an internal transition in the related defect, involving an excited state acting as a giant trap for electrons. By using the determined electron-capture coefficients, the concentration of free electrons can be found at different temperatures by a contactless method. A new classification system is suggested for defect-related PL bands in undoped GaN. PMID:27901025

Energy transfer networks: Quasicontinuum photoluminescence linked to high densities of defects

DOE PAGES

Laurence, Ted A.; Ly, Sonny; Bude, Jeff D.; ...

2017-11-06

In a series of studies related to laser-induced damage of optical materials and deposition of plastics, we discovered a broadly emitting photoluminescence with fast lifetimes that we termed quasicontinuum photoluminescence (QC-PL). Here in this paper, we suggest that a high density of optically active defects leads to QC-PL, where interactions between defects affect the temporal and spectral characteristics of both excitation and emission. We develop a model that predicts the temporal characteristics of QC-PL, based on energy transfer interactions between high densities of defects. Our model does not explain all spectral broadening and redshifts found in QC-PL, since we domore » not model spectral changes in defects due to proximity to other defects. However, we do provide an example of a well-defined system that exhibits the QC-PL characteristics of a distribution in shortened lifetimes and broadened, redshifted energy levels: an organic chromophore (fluorescein) that has been dried rapidly on a fused silica surface. Recently, we showed that regions of fused silica exposed to up to 1 billion high-fluence laser shots at 351 rm nm at subdamage fluences exhibit significant transmission losses at the surface. Here, we find that these laser-exposed regions also exhibit QC-PL. Increases in the density of induced defects on these laser-exposed surfaces, as measured by the local transmission loss, lead to decreases in the observed lifetime and redshifts in the spectrum of the QC-PL, consistent with our explanation for QC-PL. In conclusion, we have found QC-PL in an increasing variety of situations and materials, and we believe it is a phenomenon commonly found on surfaces and nanostructured materials.« less

Energy transfer networks: Quasicontinuum photoluminescence linked to high densities of defects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laurence, Ted A.; Ly, Sonny; Bude, Jeff D.

In a series of studies related to laser-induced damage of optical materials and deposition of plastics, we discovered a broadly emitting photoluminescence with fast lifetimes that we termed quasicontinuum photoluminescence (QC-PL). Here in this paper, we suggest that a high density of optically active defects leads to QC-PL, where interactions between defects affect the temporal and spectral characteristics of both excitation and emission. We develop a model that predicts the temporal characteristics of QC-PL, based on energy transfer interactions between high densities of defects. Our model does not explain all spectral broadening and redshifts found in QC-PL, since we domore » not model spectral changes in defects due to proximity to other defects. However, we do provide an example of a well-defined system that exhibits the QC-PL characteristics of a distribution in shortened lifetimes and broadened, redshifted energy levels: an organic chromophore (fluorescein) that has been dried rapidly on a fused silica surface. Recently, we showed that regions of fused silica exposed to up to 1 billion high-fluence laser shots at 351 rm nm at subdamage fluences exhibit significant transmission losses at the surface. Here, we find that these laser-exposed regions also exhibit QC-PL. Increases in the density of induced defects on these laser-exposed surfaces, as measured by the local transmission loss, lead to decreases in the observed lifetime and redshifts in the spectrum of the QC-PL, consistent with our explanation for QC-PL. In conclusion, we have found QC-PL in an increasing variety of situations and materials, and we believe it is a phenomenon commonly found on surfaces and nanostructured materials.« less

Energy transfer networks: Quasicontinuum photoluminescence linked to high densities of defects

NASA Astrophysics Data System (ADS)

Laurence, Ted A.; Ly, Sonny; Bude, Jeff D.; Baxamusa, Salmaan H.; Lepró, Xavier; Ehrmann, Paul

2017-11-01

In a series of studies related to laser-induced damage of optical materials and deposition of plastics, we discovered a broadly emitting photoluminescence with fast lifetimes that we termed quasicontinuum photoluminescence (QC-PL). Here, we suggest that a high density of optically active defects leads to QC-PL, where interactions between defects affect the temporal and spectral characteristics of both excitation and emission. We develop a model that predicts the temporal characteristics of QC-PL, based on energy transfer interactions between high densities of defects. Our model does not explain all spectral broadening and redshifts found in QC-PL, since we do not model spectral changes in defects due to proximity to other defects. However, we do provide an example of a well-defined system that exhibits the QC-PL characteristics of a distribution in shortened lifetimes and broadened, redshifted energy levels: an organic chromophore (fluorescein) that has been dried rapidly on a fused silica surface. Recently, we showed that regions of fused silica exposed to up to 1 billion high-fluence laser shots at 351 rm nm at subdamage fluences exhibit significant transmission losses at the surface. Here, we find that these laser-exposed regions also exhibit QC-PL. Increases in the density of induced defects on these laser-exposed surfaces, as measured by the local transmission loss, lead to decreases in the observed lifetime and redshifts in the spectrum of the QC-PL, consistent with our explanation for QC-PL. We have found QC-PL in an increasing variety of situations and materials, and we believe it is a phenomenon commonly found on surfaces and nanostructured materials.

The clinical significance of antiphospholipid antibodies in systemic lupus erythematosus

PubMed Central

Ünlü, Ozan; Zuily, Stephane; Erkan, Doruk

2016-01-01

Antiphospholipid syndrome (APS) is the association of thrombosis and/or pregnancy morbidity with antiphospholipid antibodies (aPL). Thirty to forty percent of systemic lupus erythematosus (SLE) patients are tested positive for aPL, which may have an impact on the SLE presentation, management, and prognosis. Compared with SLE patients without aPL, those with aPL have a higher prevalence of thrombosis, pregnancy morbidity, valve disease, pulmonary hypertension, livedo reticularis, thrombocytopenia, hemolytic anemia, acute/chronic renal vascular lesions, and moderate/severe cognitive impairment; worse quality of life; and higher risk of organ damage. The use of low-dose aspirin (LDA) is controversial for primary thrombosis and pregnancy morbidity prevention because of the lack of strong prospective controlled data. Similarly, the use of anticoagulation is controversial for patients with an aPL-related nephropathy. Until further studies are available, physicians should discuss the risk/benefits of LDA or anticoagulation as well as the available literature with patients. PMID:27708976

Imaging electronic trap states in perovskite thin films with combined fluorescence and femtosecond transient absorption microscopy

DOE PAGES

Xiao, Kai; Ma, Ying -Zhong; Simpson, Mary Jane; ...

2016-04-22

Charge carrier trapping degrades the performance of organometallic halide perovskite solar cells. To characterize the locations of electronic trap states in a heterogeneous photoactive layer, a spatially resolved approach is essential. Here, we report a comparative study on methylammonium lead tri-iodide perovskite thin films subject to different thermal annealing times using a combined photoluminescence (PL) and femtosecond transient absorption microscopy (TAM) approach to spatially map trap states. This approach coregisters the initially populated electronic excited states with the regions that recombine radiatively. Although the TAM images are relatively homogeneous for both samples, the corresponding PL images are highly structured. Themore » remarkable variation in the PL intensities as compared to transient absorption signal amplitude suggests spatially dependent PL quantum efficiency, indicative of trapping events. Furthermore, detailed analysis enables identification of two trapping regimes: a densely packed trapping region and a sparse trapping area that appear as unique spatial features in scaled PL maps.« less

Relations between policy for medical teaching and basic need satisfaction in teaching.

PubMed

Engbers, Rik; Fluit, Cornelia R M G; Bolhuis, Sanneke; Sluiter, Roderick; Stuyt, Paul M J; Laan, Roland F J M

2015-10-01

Policy initiatives that aim to elevate the position of medical teaching to that of medical research could influence the satisfaction of three basic psychological needs related to motivation for medical teaching. To explore relations between the satisfaction of three basic psychological needs towards medical teaching and two policy initiatives for medical teaching: (Junior) Principal Lecturer positions [(J)PL positions] and Subsidized Innovation and Research Projects in Medical Education (SIRPMEs). An online questionnaire was used to collect data about medical teaching in the setting of a university hospital. We adapted the Work-related Basic Need Satisfaction scale (Van den Broeck et al. in J Occup Organ Psychol, 83(4):981-1002, 2010), in order to measure feelings of autonomy, competence, and relatedness in teaching. We examined the relations between (J)PL positions and SIRPMEs and the satisfaction of three basic psychological needs. A total of 767 medical teachers participated. The initiatives appear to be related to different beneficial outcomes in terms of feelings of autonomy, competence, and relatedness in medical teaching. Either a (J)PL position is obtained by teachers who feel competent and related towards medical teaching, or obtaining a (J)PL position makes teachers feel more competent and related towards teaching, or these relations could be interacting. Also, either a SIRPME is obtained by teachers who feel competent and autonomous towards medical teaching, or obtaining a SIRPME makes teachers feel more competent and autonomous towards teaching, or these relations could be interacting. Additional research needs to scrutinize the causal or interacting relations further and to determine optimal conditions for these policy initiatives more specifically. Implications for future research are discussed.

Inactivation of Alicyclobacillus acidoterrestris ATCC 49025 spores in apple juice by pulsed light. Influence of initial contamination and required reduction levels.

PubMed

Ferrario, Mariana I; Guerrero, Sandra N

The purpose of this study was to analyze the response of different initial contamination levels of Alicyclobacillus acidoterrestris ATCC 49025 spores in apple juice as affected by pulsed light treatment (PL, batch mode, xenon lamp, 3pulses/s, 0-71.6J/cm 2 ). Biphasic and Weibull frequency distribution models were used to characterize the relationship between inoculum size and treatment time with the reductions achieved after PL exposure. Additionally, a second order polynomial model was computed to relate required PL processing time to inoculum size and requested log reductions. PL treatment caused up to 3.0-3.5 log reductions, depending on the initial inoculum size. Inactivation curves corresponding to PL-treated samples were adequately characterized by both Weibull and biphasic models (R adj 2 94-96%), and revealed that lower initial inoculum sizes were associated with higher inactivation rates. According to the polynomial model, the predicted time for PL treatment increased exponentially with inoculum size. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Where and what is the paralaminar nucleus? A review on a unique and frequently overlooked area of the primate amygdala

PubMed Central

deCampo, Danielle; Fudge, Julie

2011-01-01

The primate amygdala is composed of multiple subnuclei that play distinct roles in amygdala function. While some nuclei have been areas of focused investigation, others remain virtually unknown. One of the more obscure regions of the amygdala is the paralaminar nucleus (PL). The PL in humans and non-human primates is relatively expanded compared to lower species. Long considered to be part of the basal nucleus, the PL has several interesting features that make it unique. These features include a dense concentration of small cells, high concentrations of receptors for corticotropin releasing hormone and benzodiazepines, and dense innervation of serotonergic fibers. More recently, high concentrations of immature-appearing cells have been noted in the primate PL, suggesting special mechanisms of neural plasticity. Following a brief overview of amygdala structure and function, this review will provide an introduction to the history, embryology, anatomical connectivity, immunohistochemical and cytoarchitectural properties of the PL. Our conclusion based on the following information, is that the PL is a unique subregion of the amygdala that may yield important clues about the normal growth and function of the amygdala, particularly in higher species. PMID:21906624

Emission mechanisms in stabilized iron-passivated porous silicon: Temperature and laser power dependences

NASA Astrophysics Data System (ADS)

Rahmani, M.; Moadhen, A.; Mabrouk Kamkoum, A.; Zaïbi, M.-A.; Chtourou, R.; Haji, L.; Oueslati, M.

2012-02-01

Photoluminescence (PL) measurements of porous silicon (PS) and iron-porous silicon nanocomposites (PS/Fe) with stable optical properties versus temperature and laser power density have been investigated. The presence of iron in PS matrix is confirmed by Raman spectroscopy. The PL intensity of PS and PS/Fe increases at low temperature, the evolution of integrated PL intensity follows the modified Arrhenius model. The incorporation of iron in PS matrix reduces the activation energy traducing the existence of shallow levels related to iron atoms. Also, the temperature dependence of the porous silicon PL peak position follows a linear evolution at high temperature and a quadratic one at low temperature. Such evolution is due to the thermal carriers' redistribution and an energy transfer. Similarly, we have compared the laser power dependence of the PL in PS and PS/Fe layers. The results prove that the recombination process in PS is realised through the lower energy traps localised in the electronic gap. However, the observed emission in PS/Fe is essentially due to direct transitions. So, we can conclude that the presence of iron in PS matrix induces a strong modification of the PL mechanisms.

Circulating cell-derived microparticles in women with pregnancy loss.

PubMed

Alijotas-Reig, Jaume; Palacio-Garcia, Carles; Farran-Codina, Immaculada; Zarzoso, Cristina; Cabero-Roura, Luis; Vilardell-Tarres, Miquel

2011-09-01

To analyze cell-derived microparticles (cMP) in pregnancy loss (PL), both recurrent miscarriages (RM) and unexplained fetal loss (UFL). Non-matched case-control study was performed at Vall d'Hebron Hospital. Cell-derived microparticles of 53 PL cases, 30 with RM, 16 with UFL, and 7 (RM + UFL), were compared to 38 healthy pregnant women. Twenty healthy non-pregnant women act as controls. Cell-derived microparticles were analyzed through flow cytometry. Results are given as total annexin (A5+), endothelial-(CD144+/CD31+ CD41-), platelet-(CD41+), leukocyte-(CD45+) and CD41- c-MP/μL of plasma. Antiphospholipid antibodies (aPLA) were analyzed according to established methods. Comparing PL versus healthy pregnant, we observed a significant endothelial cMP decrease in PL. When comparing RM subgroup with controls, we observed significant decreases in endothelial cMP. When comparing the PL positive for aPLA versus PL-aPLA-negative, no cMP numbering differences were seen. Pregnancy loss seems to be related to endothelial cell activation and/or consumption. A relationship between aPLA and cMP could not be demonstrated. © 2011 John Wiley & Sons A/S.

Bias Properties of Extragalactic Distance Indicators. VIII. H0 from Distance-limited Luminosity Class and Morphological Type-Specific Luminosity Functions for SB, SBC, and SC Galaxies Calibrated Using Cepheids

NASA Astrophysics Data System (ADS)

Sandage, Allan

1999-12-01

Relative, reduced to absolute, magnitude distributions are obtained for Sb, Sbc, and Sc galaxies in the flux-limited Revised Shapley-Ames Catalog (RSA2) for each van den Bergh luminosity class (L), within each Hubble type (T). The method to isolate bias-free subsets of the total sample is via Spaenhauer diagrams, as in previous papers of this series. The distance-limited type and class-specific luminosity functions are normalized to numbers of galaxies per unit volume (105 Mpc3), rather than being left as relative functions, as in Paper V. The functions are calculated using kinematic absolute magnitudes, based on an arbitrary trial value of H0=50. Gaussian fits to the individual normalized functions are listed for each T and L subclass. As in Paper V, the data can be freed from the T and L dependencies by applying a correction of 0.23T+0.5L to the individual absolute magnitudes. Here, T=3 for Sb, 4 for Sbc, and 5 for Sc galaxies, and the L values range from 1 to 6 as the luminosity class changes from I to III-IV. The total luminosity function, obtained by combining the volume-normalized Sb, Sbc, and Sc individual luminosity functions, each corrected for the T and L dependencies, has an rms dispersion of 0.67 mag, similar to much of the Tully-Fisher parameter space. Absolute calibration of the trial kinematic absolute magnitudes is made using 27 galaxies with known T and L that also have Cepheid distances. This permits the systematic correction to the H0=50 kinematic absolute magnitudes of 0.22+/-0.12 mag, givingH0=55+/-3(internal) km s-1 Mpc-1 . The Cepheid distances are based on the Madore/Freedman Cepheid period-luminosity (PL) zero point that requires (m-M)0=18.50 for the LMC. Using the modern LMC modulus of (m-M)0=18.58 requires a 4% decrease in H0, giving a final value of H0=53+/-7 (external) by this method. These values of H0, based here on the method of luminosity functions, are in good agreement with (1) H0=55+/-5 by Theureau and coworkers from their bias-corrected Tully-Fisher method of ``normalized distances'' for field galaxies; (2) H0=56+/-4 from the method through the Virgo Cluster, as corrected to the global kinematic frame (Tammann and coworkers); and (3) H0=58+/-5 from Cepheid-calibrated Type Ia supernovae (Saha and coworkers). Our value here also disagrees with the final value from the NASA ``Key Project'' group value of H0=70+/-7. Analysis of the total flux-limited sample of Sb, Sbc, and Sc galaxies in the RSA2 by the present method, but uncorrected for selection bias, would give an incorrect value of H0=71 using the same Cepheid calibration. The effect of the bias is pernicious at the 30% level; either it must be corrected by the methods in the papers of this series, or the data must be restricted to the distance-limited subset of any sample, as is done here.

Oxygen and relative humidity monitoring with films tailored for enhanced photoluminescence

DOE PAGES

Cui, Weipan; Liu, Rui; Manna, Eeshita; ...

2014-10-31

In this study, approaches to generate porous or doped sensing films, which significantly enhance the photoluminescence (PL) of oxygen optical sensors, and thus improve the signal-to-noise (S/N) ratio, are presented. Tailored films, which enable monitoring the relative humidity (RH) as well, are also presented. Effective porous structures, in which the O 2-sensitive dye Pt octaethylporphyrin (PtOEP) or the Pd analog PdOEP was embedded, were realized by first generating blend films of polyethylene glycol (PEG) with polystyrene (PS) or with ethyl cellulose (EC), and then immersing the dried films in water to remove the water-soluble PEG. This approach creates pores (voids)more » in the sensing films. The dielectric contrast between the films’ constituents and the voids increases photon scattering, which in turn increases the optical path of the excitation light within the film, and hence light absorption by the dye, and its PL. Optimized sensing films with a PEG:PS ratio of 1:4 (PEG’s molecular weight M w ~8000) led to ~4.4× enhancement in the PL (in comparison to PS films). Lower M w ~200 PEG with a PEG:EC ratio of 1:1 led to a PL enhancement of ~4.7×. Film-dependent PL enhancements were observed at all oxygen concentrations. The strong PL enhancement enables (i) using lower dye (luminophore) concentrations, (ii) reducing power consumption and enhancing the sensor’s operational lifetime when using organic light emitting diodes (OLEDs) as excitation sources, (iii) improving performance when using compact photodetectors with no internal gain, and (iv) reliably extending the dynamic range.« less

A Round-Efficient Authenticated Key Agreement Scheme Based on Extended Chaotic Maps for Group Cloud Meeting.

PubMed

Lin, Tsung-Hung; Tsung, Chen-Kun; Lee, Tian-Fu; Wang, Zeng-Bo

2017-12-03

The security is a critical issue for business purposes. For example, the cloud meeting must consider strong security to maintain the communication privacy. Considering the scenario with cloud meeting, we apply extended chaotic map to present passwordless group authentication key agreement, termed as Passwordless Group Authentication Key Agreement (PL-GAKA). PL-GAKA improves the computation efficiency for the simple group password-based authenticated key agreement (SGPAKE) proposed by Lee et al. in terms of computing the session key. Since the extended chaotic map has equivalent security level to the Diffie-Hellman key exchange scheme applied by SGPAKE, the security of PL-GAKA is not sacrificed when improving the computation efficiency. Moreover, PL-GAKA is a passwordless scheme, so the password maintenance is not necessary. Short-term authentication is considered, hence the communication security is stronger than other protocols by dynamically generating session key in each cloud meeting. In our analysis, we first prove that each meeting member can get the correct information during the meeting. We analyze common security issues for the proposed PL-GAKA in terms of session key security, mutual authentication, perfect forward security, and data integrity. Moreover, we also demonstrate that communicating in PL-GAKA is secure when suffering replay attacks, impersonation attacks, privileged insider attacks, and stolen-verifier attacks. Eventually, an overall comparison is given to show the performance between PL-GAKA, SGPAKE and related solutions.

Antiphospholipid antibodies and non-thrombotic manifestations of systemic lupus erythematosus.

PubMed

İlgen, U; Yayla, M E; Ateş, A; Okatan, İ E; Yurteri, E U; Torgutalp, M; Keleşoğlu, A B D; Turgay, T M; Kınıklı, G

2018-04-01

Objectives The aim of this study was to investigate the association between antiphospholipid antibodies and non-thrombotic and non-gestational manifestations of systemic lupus erythematosus. Methods Systemic lupus erythematosus patients with persistently positive antiphospholipid antibodies or lupus anticoagulant were identified and grouped as systemic lupus erythematosus with antiphospholipid syndrome (SLE-APS), systemic lupus erythematosus with positive antiphospholipid antibodies/lupus anticoagulant without antiphospholipid syndrome (SLE-aPL), and systemic lupus erythematosus with negative aPLs (SLE-No aPL). Groups were compared in terms of non-thrombotic systemic lupus erythematosus manifestations and laboratory features retrospectively. Results A total of 150 systemic lupus erythematosus patients, 26 with SLE-APS, 25 with SLE-aPL, and 99 with SLE-No aPL, were identified. Livedo reticularis, neurologic involvement, and thrombocytopenia were more common in antiphospholipid antibody positive systemic lupus erythematosus cases. Malar rash, arthritis, and pleuritis were more common in the SLE-No aPL, SLE-APS, and SLE-aPL groups, respectively. Positivity rates and titers of specific antiphospholipid antibodies did not differ between the SLE-APS and SLE-aPL groups. Conclusions Presence of antiphospholipid syndrome or persistent antiphospholipid antibodies may be related to non-thrombotic and non-gestational systemic lupus erythematosus manifestations. Patients with systemic lupus erythematosus plus antiphospholipid syndrome and persistent antiphospholipid antibodies without antiphospholipid syndrome also differ in terms of systemic lupus erythematosus manifestations.

The microstructure and photoluminescence of ZnO-MoS2 core shell nano-materials

NASA Astrophysics Data System (ADS)

Yu, H.; Liu, C. M.; Huang, X. Y.; Lei, M. Y.

2017-01-01

In this paper, ZnO-MoS2-FT (FT is the fabrication temperature of MoS2) core shell nano-material samples (with ZnO as a core and MoS2 as a shell material) were fabricated on ITO substrate using hydrothermal method. The crystal structure, morphology, optical absorption and photoluminescence (PL) of samples were investigated. Compared with that of pure ZnO nanorods, ZnO-MoS2-FT samples show an enhanced light absorption. In addition, ultraviolet (UV) and visible (Vis) PL intensity of ZnO-MoS2-FT samples excited by 325 nm laser are greatly weakened. The UV PL peak position is not changed obviously. However, the Vis PL peak position is changed visibly. The Vis PL of ZnO-MoS2-FT samples under UV excitation indicates that the ratio of oxygen interstitial to oxygen vacancy is decreased. The suppression of UV PL of ZnO-MoS2-FT samples may be related to the weakening of crystal quality of ZnO, easier separation of electron-hole pairs, enhancement of light absorption, and newly introduced defects in the interface between ZnO and MoS2. Under 514 nm laser excitation, the PL peak position of ZnO-MoS2-FT samples has a red shift with FT being increased from 80 to 160 °C. The influence of excitation power (EP) on the PL of ZnO-MoS2-FT samples was also investigated. The PL of ZnO-MoS2-FT samples have a red shift with EP being increased. This may be due to the sample temperature is increased with EP, resulting an enhancement of electron-phonon interaction. A schematic diagram of charge generation and transfer is presented to understand the mechanism of PL of ZnO-MoS2 under UV and Vis excitation.

Secondary Teachers' Reflections from a Year of Professional Learning Related to Academic Language

ERIC Educational Resources Information Center

Carter, Hannah; Crowley, Kimberly; Townsend, Dianna R.; Barone, Diane

2016-01-01

This article explores the changing beliefs and practices of 25 secondary teachers participating in a yearlong professional learning (PL) partnership. To demonstrate differences in teachers' approaches to and understandings resulting from that PL, the authors looked more closely at three teachers and found that their ideas about academic language…

Excerpts from U.S. Coast Guard Regulations and Policies Related to the Edible Oil Regulatory Reform Act -- P.L. 104-55

DOT National Transportation Integrated Search

1997-04-11

The Edible Oil Regulatory Reform Act (P.L. 104-55) requires "the head of any Federal agency to differentiate between fats, oils, and greases of animal, marine, or vegetable origin, and other oils and : greases, in issuing certain regulations, and for...

Toward an embedded training tool for Deep Space Network operations

NASA Technical Reports Server (NTRS)

Hill, Randall W., Jr.; Sturdevant, Kathryn F.; Johnson, W. L.

1993-01-01

There are three issues to consider when building an embedded training system for a task domain involving the operation of complex equipment: (1) how skill is acquired in the task domain; (2) how the training system should be designed to assist in the acquisition of the skill, and more specifically, how an intelligent tutor could aid in learning; and (3) whether it is feasible to incorporate the resulting training system into the operational environment. This paper describes how these issues have been addressed in a prototype training system that was developed for operations in NASA's Deep Space Network (DSN). The first two issues were addressed by building an executable cognitive model of problem solving and skill acquisition of the task domain and then using the model to design an intelligent tutor. The cognitive model was developed in Soar for the DSN's Link Monitor and Control (LMC) system; it led to several insights about learning in the task domain that were used to design an intelligent tutor called REACT that implements a method called 'impasse-driven tutoring'. REACT is one component of the LMC training system, which also includes a communications link simulator and a graphical user interface. A pilot study of the LMC training system indicates that REACT shows promise as an effective way for helping operators to quickly acquire expert skills.

ASCA observations of the Large Magellanic Cloud supernova remnant sample: Typing supernovae from their remnants

NASA Technical Reports Server (NTRS)

Hughes, John P.; Hayashi, Ichizo; Helfand, David; Hwang, Una; Itoh, Masayuki; Kirshner, Robert; Koyama, Katsuji; Markert, Thomas; Tsunemi, Hiroshi; Woo, Jonathan

1995-01-01

We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K alpha emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, & Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based on these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last approximately 1500 yr came from Type Ia SNs.

Hubble views a spectacular supernova with interstellar material over 160,000 light-years away

NASA Image and Video Library

2017-12-08

This NASA/ESA Hubble Space Telescope image captures the remnants of a long-dead star. These rippling wisps of ionized gas, named DEM L316A, are located some 160,000 light-years away within one of the Milky Way’s closest galactic neighbors — the Large Magellanic Cloud (LMC). The explosion that formed DEM L316A was an example of an especially energetic and bright variety of supernova, known as a Type Ia. Such supernova events are thought to occur when a white dwarf star steals more material than it can handle from a nearby companion, and becomes unbalanced. The result is a spectacular release of energy in the form of a bright, violent explosion, which ejects the star’s outer layers into the surrounding space at immense speeds. As this expelled gas travels through the interstellar material, it heats up and ionizes it, producing the faint glow that Hubble’s Wide Field Camera 3 has captured here. The LMC orbits the Milky Way as a satellite galaxy and is the fourth largest in our group of galaxies, the Local Group. DEM L316A is not the only supernova remnant in the LMC; Hubble came across another one in 2010 with SNR 0509, and in 2013 it snapped SNR 0519. Image credit: ESA (European Space Agency)/Hubble & NASA, Y. Chu

Sex allocation theory reveals a hidden cost of neonicotinoid exposure in a parasitoid wasp.

PubMed

Whitehorn, Penelope R; Cook, Nicola; Blackburn, Charlotte V; Gill, Sophie M; Green, Jade; Shuker, David M

2015-05-22

Sex allocation theory has proved to be one the most successful theories in evolutionary ecology. However, its role in more applied aspects of ecology has been limited. Here we show how sex allocation theory helps uncover an otherwise hidden cost of neonicotinoid exposure in the parasitoid wasp Nasonia vitripennis. Female N. vitripennis allocate the sex of their offspring in line with Local Mate Competition (LMC) theory. Neonicotinoids are an economically important class of insecticides, but their deployment remains controversial, with evidence linking them to the decline of beneficial species. We demonstrate for the first time to our knowledge, that neonicotinoids disrupt the crucial reproductive behaviour of facultative sex allocation at sub-lethal, field-relevant doses in N. vitripennis. The quantitative predictions we can make from LMC theory show that females exposed to neonicotinoids are less able to allocate sex optimally and that this failure imposes a significant fitness cost. Our work highlights that understanding the ecological consequences of neonicotinoid deployment requires not just measures of mortality or even fecundity reduction among non-target species, but also measures that capture broader fitness costs, in this case offspring sex allocation. Our work also highlights new avenues for exploring how females obtain information when allocating sex under LMC. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

UGC 4703 Interacting Pair Near the Isolated Spiral Galaxy NGC 2718: A Milky Way Magellanic Cloud Analog

NASA Astrophysics Data System (ADS)

Paudel, Sanjaya; Sengupta, C.

2017-11-01

We present an analysis of physical and morphological properties of an interacting pair of dwarf galaxies, UGC 4703, located in the vicinity of an isolated Milky Way (MW) type spiral galaxy NGC 2718. Based on the comparison of physical and morphological properties with that of the Large and Small Magellanic Clouds (LMC and SMC), we report that the UGC 4703 pair-NGC 2718 system is probably an LMC-SMC-MW analog. Located at a sky-projected distance of 81 kpc from NGC 2718, we find that UGC 4703 is clearly interacting with its nearby lower-mass companion UGC 4703B, forming a bridge of stellar stream between them. Total B-band luminosity of UGC 4703 and its companion is -17.75 and -16.25 mag, respectively. We obtained H I 21 cm line data of UGC 4703 using the GMRT to get a more detailed view of neutral hydrogen (H I) emission. The H I image revealed evidence of interaction between the dwarf galaxy pair but no extended emission, such as the Magellanic Stream. We also detected star-forming regions along the UGC 4703/4703B bridge with stellar mass exceeding 107 M ⊙. While comparing the optical and H I morphology of the interacting dwarf pairs (UGC 4703-4703B and LMC-SMC), we discuss possible differences in interaction histories of these systems.

Clustering of local group distances: Publication bias or correlated measurements? II. M31 and beyond

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Grijs, Richard; Bono, Giuseppe

2014-07-01

The accuracy of extragalactic distance measurements ultimately depends on robust, high-precision determinations of the distances to the galaxies in the local volume. Following our detailed study addressing possible publication bias in the published distance determinations to the Large Magellanic Cloud (LMC), here we extend our distance range of interest to include published distance moduli to M31 and M33, as well as to a number of their well-known dwarf galaxy companions. We aim at reaching consensus on the best, most homogeneous, and internally most consistent set of Local Group distance moduli to adopt for future, more general use based on themore » largest set of distance determinations to individual Local Group galaxies available to date. Based on a careful, statistically weighted combination of the main stellar population tracers (Cepheids, RR Lyrae variables, and the magnitude of the tip of the red-giant branch), we derive a recommended distance modulus to M31 of (m−M){sub 0}{sup M31}=24.46±0.10 mag—adopting as our calibration an LMC distance modulus of (m−M){sub 0}{sup LMC}=18.50 mag—and a fully internally consistent set of benchmark distances to key galaxies in the local volume, enabling us to establish a robust and unbiased, near-field extragalactic distance ladder.« less

Chemical Abundances of Two Stars in the Large Magellanic Cloud Globular Cluster NGC 1718

NASA Astrophysics Data System (ADS)

Sakari, Charli M.; McWilliam, Andrew; Wallerstein, George

2017-05-01

Detailed chemical abundances of two stars in the intermediate-age Large Magellanic Cloud (LMC) globular cluster NGC 1718 are presented, based on high-resolution spectroscopic observations with the MIKE spectrograph. The detailed abundances confirm NGC 1718 to be a fairly metal-rich cluster, with an average [Fe/H] ˜ -0.55 ± 0.01. The two red giants appear to have primordial O, Na, Mg and Al abundances, with no convincing signs of a composition difference between the two stars - hence, based on these two stars, NGC 1718 shows no evidence for hosting multiple populations. The Mg abundance is lower than Milky Way field stars, but is similar to LMC field stars at the same metallicity. The previous claims of very low [Mg/Fe] in NGC 1718 are therefore not supported in this study. Other abundances (Si, Ca, Ti, V, Mn, Ni, Cu, Rb, Y, Zr, La and Eu) all follow the LMC field star trend, demonstrating yet again that (for most elements) globular clusters trace the abundances of their host galaxy's field stars. Similar to the field stars, NGC 1718 is found to be mildly deficient in explosive α-elements, but moderately to strongly deficient in O, Na, Mg, Al and Cu, elements that form during hydrostatic burning in massive stars. NGC 1718 is also enhanced in La, suggesting that it was enriched in ejecta from metal-poor asymptotic giant branch stars.

Platelet lysate induces chondrogenic differentiation of umbilical cord-derived mesenchymal stem cells.

PubMed

Hassan, Ghmkin; Bahjat, Mohammad; Kasem, Issam; Soukkarieh, Chadi; Aljamali, Majd

2018-01-01

Articular cartilage has a poor capacity for self-repair, and thus still presents a major challenge in orthopedics. Mesenchymal stem cells (MSCs) are multipotent stem cells with the potential to differentiate into chondrocytes in the presence of transforming growth factor beta (TGF-β). Platelet lysate (PL) contains a relatively large number of growth factors, including TGF-β, and has been shown to ameliorate cartilage repair. Here, we investigated the ability of PL to direct chondrogenic differentiation of MSCs along with other standard differentiation components in a pellet culture system. We isolated and expanded MSCs from human umbilical cords using a PL-supplemented medium and characterized the cells based on immunophenotype and potential for differentiation to adipocytes and osteocytes. We further cultured MSCs as pellets in a chondrogenic-differentiation medium supplemented with PL. After 21 days, the pellets were processed for histological analysis and stained with alician blue and acridine orange. The expression of SOX9 was investigated using RT-PCR. MSCs maintained their stemness characteristics in the PL-supplemented medium. However, the distribution of cells in the pellets cultured in the PL-supplemented chondrogenic differentiation medium had a greater similarity to cartilage tissue-derived chondrocytes than to the negative control. The intense alician blue staining indicated an increased production of mucopolysaccharides in the differentiated pellets, which also showed elevated expression of SOX9 . Our data suggest that MSCs could be differentiated to chondrocytes in the presence of PL and absence of exogenous TGF-β. Further research needs to be conducted to understand the exact role and potential of PL in chondrogenic differentiation and chondrocyte regeneration.

Enhanced ε-poly-L-lysine production by inducing double antibiotic-resistant mutations in Streptomyces albulus.

PubMed

Wang, Liang; Chen, Xusheng; Wu, Guangyao; Li, Shu; Zeng, Xin; Ren, Xidong; Tang, Lei; Mao, Zhonggui

2017-02-01

ε-Poly-L-lysine (ε-PL), as a food additive, has been widely used in many countries. However, its production still needs to be improved. We successfully enhanced ε-PL production of Streptomyces albulus FEEL-1 by introducing mutations related to antibiotics, such as streptomycin, gentamicin, and rifampin. Single- and double-resistant mutants (S-88 and SG-31) were finally screened with the improved ε-PL productions of 2.81 and 3.83 g/L, 1.75- to 2.39-fold compared with that of initial strain FEEL-1. Then, the performances of mutants S-88 and SG-31 were compared with the parent strain FEEL-1 in a 5-L bioreactor under the optimal condition for ε-PL production. After 174-h fed-batch fermentation, the ε-PL production and productivity of hyper-strain SG-31 reached the maximum of 59.50 g/L and 8.21 g/L/day, respectively, which was 138 and 105% higher than that of FEEL-1. Analysis of streptomycin-resistant mutants demonstrated that a point mutation occurred in rpsL gene (encoding the ribosomal protein S12). These single and double mutants displayed remarkable increases of the activities and transcriptional levels of key enzymes in ε-PL biosynthesis pathway, which may be responsible for the enhanced mycelia viability, respiratory activity, and ε-PL productions of SG-31. These results showed that the new breeding method, called ribosome engineering, could be a novel and effective breeding strategy for the evolution of ε-PL-producing strains.

Comparative Analysis of EPA/DHA-PL Forage and Liposomes in Orotic Acid-Induced Nonalcoholic Fatty Liver Rats and Their Related Mechanisms.

PubMed

Chang, Mengru; Zhang, Tiantian; Han, Xiuqing; Tang, Qingjuan; Yanagita, Teruyoshi; Xu, Jie; Xue, Changhu; Wang, Yuming

2018-02-14

Nonalcoholic fatty liver disease (NAFLD) has become one predictive factor of death from various illnesses. The present study was to comparatively investigate the effects of eicosapentaenoic acid-enriched and docosahexaenoic acid-enriched phospholipids forage (EPA-PL and DHA-PL) and liposomes (lipo-EPA and lipo-DHA) on NAFLD and demonstrate the possible protective mechanisms involved. The additive doses of EPA-PL and DHA-PL in all treatment groups were 1% of total diets, respectively. The results showed that Lipo-EPA could significantly improve hepatic function by down-regulating orotic acid-induced serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels by 55.6% and 34.2%, respectively (p < 0.01). Moreover, lipo-EPA exhibited excellent inhibition on the mRNA expression of SREBP-1c and FAS at the values of 0.454 ± 0.09 (p < 0.01) and 0.523 ± 0.08 (p < 0.01), respectively, thus ameliorating OA-induced NAFLD. Meanwhile, lipo-EPA could significantly suppress the SREBP-2 and HMGR levels (31.4% and 66.7%, p < 0.05, respectively). In addition, EPA-PL and lipo-DHA could also significantly suppress hepatic lipid accumulation mainly by enhancement of hepatic lipolysis and cholesterol efflux. Furthermore, DHA-PL played a certain role in inhibiting hepatic lipogenesis and accelerating cholesterol efflux. The results obtained in this work might contribute to the understanding of the biological activities of EPA/DHA-PL and liposomes and further investigation on its potential application values for food supplements.

Diagnostic Performance of Placental Growth Factor in Women With Suspected Preeclampsia Attending Antenatal Facilities in Maputo, Mozambique.

PubMed

Ukah, U Vivian; Mbofana, Francisco; Rocha, Beatriz Manriquez; Loquiha, Osvaldo; Mudenyanga, Chishamiso; Usta, Momade; Urso, Marilena; Drebit, Sharla; Magee, Laura A; von Dadelszen, Peter

2017-03-01

In well-resourced settings, reduced circulating maternal-free placental growth factor (PlGF) aids in either predicting or confirming the diagnosis of preeclampsia, fetal growth restriction, stillbirth, preterm birth, and delivery within 14 days of testing when preeclampsia is suspected. This blinded, prospective cohort study of maternal plasma PlGF in women with suspected preeclampsia was conducted in antenatal clinics in Maputo, Mozambique. The primary outcome was the clinic-to-delivery interval. Other outcomes included: confirmed diagnosis of preeclampsia, transfer to higher care, mode of delivery, intrauterine fetal death, preterm birth, and low birth weight. Of 696 women, 95 (13.6%) and 601 (86.4%) women had either low (<100 pg/mL) or normal (≥100 pg/mL) plasma PlGF, respectively. The clinic-to-delivery interval was shorter in low PlGF, compared with normal PlGF, women (median 24 days [interquartile range, 10-49] versus 44 [24-81], P =0.0042). Also, low PlGF was associated with a confirmed diagnosis of preeclampsia, higher blood pressure, transfer for higher care, earlier gestational age delivery, delivery within 7 and 14 days, preterm birth, cesarean delivery, lower birth weight, and perinatal loss. In urban Mozambican women with symptoms or signs suggestive of preeclampsia, low maternal plasma PlGF concentrations are associated with increased risks of adverse pregnancy outcomes, whether the diagnosis of preeclampsia is confirmed. Therefore, PlGF should improve the provision of precision medicine to individual women and improve pregnancy outcomes for those with preeclampsia or related placenta-mediated complications. © 2017 American Heart Association, Inc.

Technology and Children with Disabilities: A Guide for Family Members. P.L. 100-407: Technology-Related Assistance for Individuals with Disabilities Act of 1988. P.L. 100-360: Medicare Catastrophic Coverage Act.

ERIC Educational Resources Information Center

Turnbull, H. Rutherford, III

The booklet describes the provisions and the significance of two laws which provide technology services or devices for persons with disabilities: Public Law 100-407, the Technology Related Assistance for Individuals with Disabilities Act of 1988; and Public Law 100-360, the Medicare Catastrophic Coverage Act. The first authorizes federal funds to…

Community-wide assessment of pollen limitation in hummingbird-pollinated plants of a tropical montane rain forest

PubMed Central

Wolowski, Marina; Ashman, Tia-Lynn; Freitas, Leandro

2013-01-01

Background and Aims Although pollen limitation of reproduction (PL) has been widely studied, our understanding of its occurrence in tropical communities, especially for bird-pollinated plants, is underdeveloped. In addition, inclusion of both quantity and quality aspects in studies of PL are generally lacking. Within hummingbird-pollinated plants, a prediction was made for higher PL for the quality than quantity aspects and a minor effect of temporal variation because hummingbirds are constant and efficient pollen vectors but they may transfer low quality pollen. Methods Field hand and open pollination experiments were conducted on 21 species in a tropical montane rain forest over 2 years. The quantity (fruit set and seeds per fruit) and quality (seed weight and germination) aspects of reproduction were assessed as the response to open pollination relative to outcross hand pollination. The relationships between the effect size of quantity and quality aspects of reproduction and predictive plant features (self-incompatibility, autogamy, density and pollinator specialization level) were assessed with phylogenetic generalized linear models. Key Results Just over half of all the species expressed PL for one or more response variables. On average, the severity of PL was strong for one quality variable (seed germination; 0·83), but insignificant for another (seed weight; –0·03), and low to moderate for quantity variables (0·31 for seeds per fruit and 0·39 for fruit set). There was only a minor contribution of temporal variation to PL within the studied species. Common predictors of PL, i.e. phylogenetic relatedness, self-incompatibility, autogamy, plant density and pollinator specialization level, did not adequately explain variation in PL within this community. Conclusions Despite the measurable degree of PL within these hummingbird-pollinated plants, the causes of pollen quality and quantity insufficiency are not clear. Variables other than those tested may contribute to PL or causes of PL may vary among species and cannot adequately be accounted for when assessed from the within-community perspective. PMID:23845434

Photoluminescence due to early stage of oxygen precipitation in multicrystalline Si for solar cells

NASA Astrophysics Data System (ADS)

Higuchi, Fumito; Tajima, Michio; Ogura, Atsushi

2017-07-01

To analyze the early stage of oxygen precipitation in n-type multicrytalline Si, the spectral change of photoluminescence (PL) induced by thermal treatment at 450-650 °C was investigated in relation to the changes in excess donor and interstitial oxygen concentrations. We observed the characteristic PL bands in the near-band-edge region and sharp lines in the deep-level region in correspondence with the generation of thermal donors and new donors. The observed PL spectral variation is essentially the same as that in Czochralski-grown Si annealed at 450-650 °C.

Spatially resolved surface-related exciton polariton dynamics in a single ZnO tetrapod

NASA Astrophysics Data System (ADS)

Sun, Fangfang; Sun, Liaoxin; Zhang, Bo; Wang, Hailong

2018-02-01

The band-edge emission lifetime in a single ZnO tetrapod is studied by using the time-resolved confocal micro-photoluminescence (TR- μPL) spectroscopic technique at room temperature. By performing μPL and TR- μPL mapping along the tapered arm of tetrapod, we observe whispering gallery mode (WGM) polaritons and find that the predominant radiative lifetime of exciton polaritons decreases linearly with increasing the surface-to-volume ratio of the sample. This behavior is ascribed to the surface electric field induced enhancement of the radiative decay rate of the exciton-like polaritons coupling with LO phonons.

Synthesis and properties of Rb2GeF6:Mn4+ red-emitting phosphors

NASA Astrophysics Data System (ADS)

Sakurai, Shono; Nakamura, Toshihiro; Adachi, Sadao

2018-02-01

Rb2GeF6:Mn4+ red-emitting phosphors were synthesized by coprecipitation and their structural and optical properties were investigated by laser microscopy observation, X-ray diffraction (XRD) analysis, photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, and PL decay measurement. Single-crystalline ingots in the form of a hexagonal pyramid were prepared with a basal plane diameter of ˜2 mm. The XRD analysis suggested that Rb2GeF6 crystallizes in the hexagonal structure (C6v4 = P63mc) with a = 0.5955 nm and c = 0.9672 nm. The phosphor exhibited the strong Mn4+-related zero-phonon line (ZPL) emission peak typically observed in host crystals with piezoelectrically active lattices such as a hexagonal lattice. The quantum efficiencies of the bulk ingot and powdered samples were 87 and 74%, respectively, with nearly the same luminescence decay time of ˜6 ms. The exact ZPL energies and related crystal-field and Racah parameters were obtained from the PL and PLE spectra by Franck-Condon analysis. Temperature-dependent PL intensities were analyzed from T = 20 to 500 K using a thermal quenching model by considering Bose-Einstein phonon statistics. A comparative discussion on the phosphor properties of Rb2GeF6:Mn4+ and Rb2MF6:Mn4+ with M = Si and Ti was also given.

Impact of extended defects on recombination in CdTe heterostructures grown by molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Zaunbrecher, Katherine N.; Kuciauskas, Darius; Swartz, Craig H.; Dippo, Pat; Edirisooriya, Madhavie; Ogedengbe, Olanrewaju S.; Sohal, Sandeep; Hancock, Bobby L.; LeBlanc, Elizabeth G.; Jayathilaka, Pathiraja A. R. D.; Barnes, Teresa M.; Myers, Thomas H.

2016-08-01

Heterostructures with CdTe and CdTe1-xSex (x ˜ 0.01) absorbers between two wider-band-gap Cd1-xMgxTe barriers (x ˜ 0.25-0.3) were grown by molecular beam epitaxy to study carrier generation and recombination in bulk materials with passivated interfaces. Using a combination of confocal photoluminescence (PL), time-resolved PL, and low-temperature PL emission spectroscopy, two extended defect types were identified and the impact of these defects on charge-carrier recombination was analyzed. The dominant defects identified by confocal PL were dislocations in samples grown on (211)B CdTe substrates and crystallographic twinning-related defects in samples on (100)-oriented InSb substrates. Low-temperature PL shows that twin-related defects have a zero-phonon energy of 1.460 eV and a Huang-Rhys factor of 1.50, while dislocation-dominated samples have a 1.473-eV zero-phonon energy and a Huang-Rhys factor of 1.22. The charge carrier diffusion length near both types of defects is ˜6 μm, suggesting that recombination is limited by diffusion dynamics. For heterostructures with a low concentration of extended defects, the bulk lifetime was determined to be 2.2 μs with an interface recombination velocity of 160 cm/s and an estimated radiative lifetime of 91 μs.

Impact of extended defects on recombination in CdTe heterostructures grown by molecular beam epitaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaunbrecher, Katherine N.; Kuciauskas, Darius; Swartz, Craig H.

Heterostructures with CdTe and CdTe 1-xSex (x ~ 0.01) absorbers between two wider-band-gap Cd1-xMgxTe barriers (x ~ 0.25-0.3) were grown by molecular beam epitaxy to study carrier generation and recombination in bulk materials with passivated interfaces. Using a combination of confocal photoluminescence (PL), time-resolved PL, and low-temperature PL emission spectroscopy, two extended defect types were identified and the impact of these defects on charge-carrier recombination was analyzed. The dominant defects identified by confocal PL were dislocations in samples grown on (211)B CdTe substrates and crystallographic twinning-related defects in samples on (100)-oriented InSb substrates. Low-temperature PL shows that twin-related defects havemore » a zero-phonon energy of 1.460 eV and a Huang-Rhys factor of 1.50, while dislocation-dominated samples have a 1.473-eV zero-phonon energy and a Huang-Rhys factor of 1.22. The charge carrier diffusion length near both types of defects is ~6 um, suggesting that recombination is limited by diffusion dynamics. For heterostructures with a low concentration of extended defects, the bulk lifetime was determined to be 2.2 us with an interface recombination velocity of 160 cm/s and an estimated radiative lifetime of 91 us.« less

Plasma levels of hypoxia-regulated factors in patients with age-related macular degeneration.

PubMed

Ioanna, Zygoula; Christian, Schori; Christian, Grimm; Daniel, Barthelmes

2018-02-01

Various hypoxia-related proteins are differentially expressed in the retina and secreted to the vitreous and/or aqueous humor of patients affected by dry or neovascular age-related macular degeneration (nAMD). To determine whether these conditions alter concentrations of cytokines also in the systemic circulation, we measured plasma levels of six hypoxia-related proteins. Plasma was prepared from EDTA blood that was collected from patients affected by dry AMD (n = 5), nAMD (n = 11), proliferative diabetic retinopathy (PDR; n = 9), and patients with an epiretinal membrane (ERM; n = 11). ERM samples served as negative controls, PDR samples as positive controls. Protein concentrations of vascular endothelial growth factor (VEGF), erythropoietin (EPO), angiopoietin-like 4 (ANGPTL4), placental growth factor (PlGF), tumor necrosis factor alpha (TNF-α), and pigment epithelium-derived factor (PEDF) were determined by enzyme-linked immunosorbent assay (ELISA). The concentration of PlGF was significantly increased in plasma of patients affected by nAMD. Although no statistically significant differences were found for EPO, ANGPTL4, PlGF, TNF-α, and PEDF, the mean concentration of VEGF was lowest in the nAMD group. Plasma concentrations of the six factors did not correlate with gender or age of patients. nAMD may increase plasma concentrations of PlGF, making it a candidate as a biomarker for the neovascular form of AMD. Other factors, however, were not differentially regulated, suggesting that their systemic concentrations are not generally increased in hypoxia-related retinal diseases.

The Multiple Stellar Populations in the Ancient LMC Globular Clusters Hodge 11 and NGC 2210

NASA Astrophysics Data System (ADS)

Chaboyer, Brian; Gilligan, Christina; Wagner-Kaiser, Rachel; Mackey, Dougal; Sarajedini, Ata; Cummings, Jeffrey; Grocholski, Aaron; Geisler, Doug; Cohen, Roger; Villanova, Sandro; Yang, Soung-Chul; Parisi, Celeste

2018-01-01

Hubble Space telescope images of the ancient LMC globular clusters Hodge 11 and NGC 2210 in the F336W, F606W and F814W filters were obtained between June 2016 and April 2017. These deep images has been analyzed with the Dolphot software package. High quality photometry has been obtained from three magnitudes brighter than the horizontal branch, to about four magnitudes fainter than the main sequence turn-off. Both clusters show an excess of red main sequence stars in the F336W filter, indicating that multiple stellar populations exist in both clusters. Hodge 11 shows irregularities in its horizontal branch morphology, which is indicative of the presence of an approximately 0.1 dex internal helium abundance spread.

CORS BAADE-WESSELINK DISTANCE TO THE LMC NGC 1866 BLUE POPULOUS CLUSTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molinaro, R.; Ripepi, V.; Marconi, M.

2012-03-20

We used optical, near-infrared photometry, and radial velocity data for a sample of 11 Cepheids belonging to the young LMC blue populous cluster NGC 1866 to estimate their radii and distances on the basis of the CORS Baade-Wesselink method. This technique, based on an accurate calibration of surface brightness as a function of (U - B), (V - K) colors, allows us to estimate, simultaneously, the linear radius and the angular diameter of Cepheid variables, and consequently to derive their distance. A rigorous error estimate on radii and distances was derived by using Monte Carlo simulations. Our analysis gives amore » distance modulus for NGC 1866 of 18.51 {+-} 0.03 mag, which is in agreement with several independent results.« less

Our Galactic Neighbor Hosts Complex Organic Molecules

NASA Astrophysics Data System (ADS)

Hensley, Kerry

2018-03-01

For the first time, data from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the presence of methyl formate and dimethyl ether in a star-forming region outside our galaxy. This discovery has important implications for the formation and survival of complex organic compounds importantfor the formation of life in low-metallicity galaxies bothyoung and old.No Simple Picture of Complex Molecule FormationALMA, pictured here with the Magellanic Clouds above, has observed organic molecules in our Milky Way Galaxy and beyond. [ESO/C. Malin]Complex organic molecules (those with at least six atoms, one or more of which must be carbon) are the precursors to the building blocks of life. Knowing how and where complex organic molecules can form is a key part of understanding how life came to be on Earth and how it might arise elsewhere in the universe. From exoplanet atmospheres to interstellar space, complex organic molecules are ubiquitous in the Milky Way.In our galaxy, complex organic molecules are often found in the intense environments of hot cores clumps of dense molecular gas surrounding the sites of star formation. However, its not yet fully understood how the complex organic molecules found in hot cores come to be. One possibility is that the compounds condense onto cold dust grains long before the young stars begin heating their natal shrouds. Alternatively, they might assemble themselves from the hot, dense gas surrounding the blazing protostars.Composite infrared and optical image of the N 113 star-forming region in the LMC. The ALMA coverage is indicated by the gray line. Click to enlarge. [Sewio et al. 2018]Detecting Complexity, a Galaxy AwayUsing ALMA, a team of researchers led by Marta Sewio (NASA Goddard Space Flight Center) recently detected two complex organic molecules methyl formate and dimethyl ether for the first time in our neighboring galaxy, the Large Magellanic Cloud (LMC). Previous searches for organic molecules in the LMC detected small amounts of methanol, the parentmolecule of the two newly-discovered compounds. By revealing the spectral signatures of dimethyl ether and methyl formate, Sewio and collaboratorsfurther prove thatorganic chemistry is hard at work in hot cores in the LMC.This discovery is momentous because dwarf galaxies like theLMC tend to have a lower abundance of the heavy elements that make up complex organic molecules most importantly, oxygen, carbon, and nitrogen. Beyond lacking the raw materials necessary to create complex molecules, the gas of low-metallicity galaxies does a poorer job preventing the penetration of high-energy photons. The impinging photons warm dust grains, resulting in a lower probability of forming and maintaining complex organic molecules. Despite this, organic molecules appear to beable todevelop and persist which has exciting implications for organic chemistry in low-metallicity environments.ALMA observation of emission by methyl formate in a hot core in the LMC.[Adapted from Sewio et al. 2018]A Lens into the PastIn the early universe, before the budding galaxies have had time to upcycle their abundant hydrogen into heavier elements, organic chemistry is thought to proceed slowly or not at all. The discovery of complex organic molecules in a nearby low-metallicity galaxy upends this theory and propels us toward a better understanding of the organic chemistry in the early universe.CitationMarta Sewio et al 2018ApJL853L19. doi:10.3847/2041-8213/aaa079

Amino compounds in poultry litter, litter-amended pasture soils and grass shoots

USDA-ARS?s Scientific Manuscript database

Organic N accounts for 95-98% of total soil N contents with amino compounds (ACs) as major ingredients. But relatively little is known about the effects of poultry litter (PL) application on soil AC pools and turnover. In this work, we determined 21 AC contents in 23 PL samples, 15 soil samples with...

Some Observations on the Identification and Interpretation of the 3PL IRT Model

ERIC Educational Resources Information Center

Azevedo, Caio Lucidius Naberezny

2009-01-01

The paper by Maris, G., & Bechger, T. (2009) entitled, "On the Interpreting the Model Parameters for the Three Parameter Logistic Model," addressed two important questions concerning the three parameter logistic (3PL) item response theory (IRT) model (and in a broader sense, concerning all IRT models). The first one is related to the model…

VizieR Online Data Catalog: Spitzer/IRS obs. of Magellanic carbon stars (Sloan+, 2016)

NASA Astrophysics Data System (ADS)

Sloan, G. C.; Kraemer, K. E.; McDonald, I.; Groenewegen, M. A. T.; Wood, P. R.; Zijlstra, A. A.; Lagadec, E.; Boyer, M. L.; Kemper, F.; Matsuura, M.; Sahai, R.; Sargent, B. A.; Srinivasan, S.; van Loon, J. T.; Volk, K.

2016-09-01

Table 1 lists the 144 objects in the LMC and 40 in the SMC observed with the IRS (spectral coverage at 5-14um and 14-37um, respectively, with a resolution R~80-120) and identified as carbon stars. A variety of Spitzer observing programs contributed to the present sample of carbon stars (see Note 2 in table 1). We adopt distance moduli for the LMC and SMC of 18.5 and 18.9, respectively. For all of our targets, we have constructed SEDs based on multi-epoch photometry in the optical, near-IR, and mid-IR from several surveys. The mid-IR data come from the SAGE survey of the LMC (Meixner et al. 2006, J/AJ/132/2268) and the SAGE-SMC survey for the SMC (Gordon et al. 2011AJ....142..102G)). The SAGE-VAR survey adds four epochs from the Warm Spitzer Mission at 3.6 and 4.5um for portions of the LMC and SMC (Riebel et al. 2015ApJ...807....1R). We also used additional epochs at 3.4 and 4.6um from the Wide-field Infrared Survey Experiment (WISE; Wright et al. 2010AJ....140.1868W) and the NEOWISE reactivation mission (Mainzer et al. 2014ApJ...792...30M). Near-IR photometry comes from the 2MASS survey, and the deeper 2MASS-6X survey provides a second epoch at J, H, and Ks (Cutri et al. 2012, II/281; Skrutskie et al. 2006, VII/233). Additional epochs come from the Deep Near-IR Survey of the Southern Sky (DENIS) at J and Ks (Cioni et al. 2000, II/228) and the IR Survey Facility (IRSF) at J, H, and Ks (Kato et al. 2007, II/288). In the optical, we relied on the Magellanic Clouds Photometric Survey (MCPS) at U, B, V, and I (Zaritsky et al. 2002, J/AJ/123/855; 2004, J/AJ/128/1606). DENIS adds data at I. Additional mean magnitudes at V and I in the LMC come from the OGLE-III Shallow Survey (Ulaczyk et al. 2013, J/AcA/63/1). Where possible, we replaced the V and I data with mean magnitudes from the OGLE-III surveys of the Magellanic Clouds, which also give pulsation periods and amplitudes (Soszynski et al. 2009, J/AcA/59/335; 2011, J/AcA/61/217). We also consider a Galactic control sample using spectra from the Short-Wavelength Spectrometer (SWS) on the Infrared Space Observatory (ISO); see section 2.5. (7 data files).

Characterization of potential plasma biomarkers related to cognitive impairment by untargeted profiling of phospholipids using the HILIC-ESI-IT-TOF-MS system.

PubMed

Song, Shuang; Cheong, Ling-Zhi; Man, Qing-Qing; Pang, Shao-Jie; Li, Yue-Qi; Ren, Biao; Zhang, Jian

2018-05-01

Early diagnosis of neural changes causing cognitive impairment is critical for development of preventive therapies for dementia. Biomarkers currently characterized cannot be extensively applied due to the invasive sampling of cerebrospinal fluid. The other imaging approaches are either expensive or require a high technique. Phospholipids (PLs), which are basic constituents of neurons, might be a key variable in the pathogenesis of cognitive impairment. Changes in plasma PL provide the possibility for development of novel biomarkers with minimal invasion and high patient acceptance. In this work, a HILIC-ESI-IT-TOF-MS system was introduced for untargeted profiling of plasma PLs to investigate the relationship between changes of plasma PL profiles and cognitive impairment. A total of 272 types of PL molecular structures were characterized in human plasma and quantified through the internal standard method. Univariate analysis shows 29 PLs were significantly different between the control (n = 41) and the cognitive impairment (CI) group (n = 41). Multivariate analysis (PCA and OPLS-DA) was conducted based on these 29 potential PL biomarkers. Both univariate and multivariate analyses show abnormality of PL metabolism in the CI group, and the downregulation of ethanolamine plasmalogen (pPE) supply, especially those with PUFAs, in the circulation system should be strongly associated with neurodegeneration. A discriminative model was established with satisfied fit (R2) and prediction (Q2) abilities, and the classification test showed better recognition of the CI group than the control group indicating that this model of PL biomarkers could be used as indicators for screening of CI. Graphical abstract Characterization of potential plasma biomarkers related to cognitive impairment by untargeted profiling of phospholipids.

Synopsis of Precision Landing and Hazard Avoidance (PL&HA) Capabilities for Space Exploration

NASA Technical Reports Server (NTRS)

Robertson, Edward A.

2017-01-01

Until recently, robotic exploration missions to the Moon, Mars, and other solar system bodies relied upon controlled blind landings. Because terrestrial techniques for terrain relative navigation (TRN) had not yet been evolved to support space exploration, landing dispersions were driven by the capabilities of inertial navigation systems combined with surface relative altimetry and velocimetry. Lacking tight control over the actual landing location, mission success depended on the statistical vetting of candidate landing areas within the predicted landing dispersion ellipse based on orbital reconnaissance data, combined with the ability of the spacecraft to execute a controlled landing in terms of touchdown attitude, attitude rates, and velocity. In addition, the sensors, algorithms, and processing technologies required to perform autonomous hazard detection and avoidance in real time during the landing sequence were not yet available. Over the past decade, NASA has invested substantial resources on the development, integration, and testing of autonomous precision landing and hazard avoidance (PL&HA) capabilities. In addition to substantially improving landing accuracy and safety, these autonomous PL&HA functions also offer access to targets of interest located within more rugged and hazardous terrain. Optical TRN systems are baselined on upcoming robotic landing missions to the Moon and Mars, and NASA JPL is investigating the development of a comprehensive PL&HA system for a Europa lander. These robotic missions will demonstrate and mature PL&HA technologies that are considered essential for future human exploration missions. PL&HA technologies also have applications to rendezvous and docking/berthing with other spacecraft, as well as proximity navigation, contact, and retrieval missions to smaller bodies with microgravity environments, such as asteroids.

Optical properties of ion-beam-synthesized Au nanoparticles in SiO2 matrix

NASA Astrophysics Data System (ADS)

Hsieh, Chang-Lin; Oyoshi, Keiji; Chao, Der-Sheng; Tsai, Hsu-Sheng; Hong, Wei-Lun; Takeda, Yoshihiko; Liang, Jenq-Horng

2016-05-01

In recent years, gold (Au) nanoparticles have been synthesized via various methods and used in optical and biomedical detection. Au nanoparticles contain some remarkable dimension-dependent optical properties due to surface plasmon resonance (SPR) in Au nanoparticles which causes high absorption in visible light regions. Since SPR in well-crystallized Au nanoparticles can enhance the local electromagnetic field, it is thus expected that greater efficiency in the photoluminescence (PL) originating from oxygen deficiency centers (ODC) can be achieved in Au-implanted SiO2 matrix. In order to demonstrate the enhancement of PL, Au nanoparticles were formed in SiO2 film using ion beam synthesis and their optical and microstructural properties were also investigated in this study. The results revealed that a clear absorption peak at approximately 530 nm was identified in the UV-Vis spectra and was attributed to SPR induced by Au nanoparticles in SiO2. The SPR of Au nanoparticles is also dependent on thermal treatment conditions, such as post-annealing temperature and ambient. The Au nanoparticle-containing SiO2 film also displayed several distinctive peaks at approximately 320, 360, 460, and 600 nm in the PL spectra and were found to be associated with ODC-related defects and non-bridging oxygen hole centers (NBOHC) in SiO2. In addition, the PL peak intensities increased as post-annealing temperature increased, a finding contradictory to the defect recovery but highly consistent with the SPR tendency. A maximum PL emission was achieved when the Au-implanted SiO2 film was annealed at 1100 °C for 1 h under N2. Therefore, the existence of Au nanoparticles in SiO2 film can induce SPR effects as well as enhance PL emission resulting from defect-related luminescence centers.

THE MID-INFRARED EXTINCTION LAW IN THE LARGE MAGELLANIC CLOUD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Jian; Jiang, B. W.; Xue, M. Y.

Based on photometric data from the Spitzer/SAGE survey, using red giants as extinction tracers, the mid-infrared (MIR) extinction laws in the Large Magellanic Cloud (LMC) are derived for the first time in the form of A{sub λ}/A{sub K{sub S}}. This quantity refers to the extinction in the four Infrared Array Camera (IRAC) bands (i.e., [3.6], [4.5], [5.8], and [8.0] μm) relative to the Two Micron All Sky Survey K{sub S} band at 2.16 μm. We obtain the near-infrared extinction coefficient to be E(J – H)/E(H – K{sub S} ) ≈ 1.29 ± 0.04 and E(J – K{sub S} )/E(H –more » K{sub S} ) ≈ 1.94 ± 0.04. The wavelength dependence of the MIR extinction A{sub λ}/A{sub K{sub S}} in the LMC varies from one sightline to another. The overall mean MIR extinction is A{sub [3.6]}/A{sub K{sub S}}∼0.72±0.03, A{sub [4.5]}/A{sub K{sub S}}∼0.94±0.03, A{sub [5.8]}/A{sub K{sub S}}∼0.58±0.04, and A{sub [8.0]}/A{sub K{sub S}}∼0.62±0.05. Except for the extinction in the IRAC [4.5] μm band, which may be contaminated by the 4.6 μm CO gas absorption of red giants used to trace LMC extinction, the extinction in the other three IRAC bands show a flat curve, close to the Milky Way R{sub V} = 5.5 model extinction curve, where R{sub V} is the optical total-to-selective extinction ratio. The possible systematic bias caused by the correlated uncertainties of K{sub S} – λ and J – K{sub S} is explored in terms of Monte Carlo simulations. We find that this bias could lead to an overestimation of A{sub λ}/A{sub K{sub S}} in the MIR.« less

Massive Star Cluster Populations in Irregular Galaxies as Probable Younger Counterparts of Old Metal-rich Globular Cluster Populations in Spheroids

NASA Astrophysics Data System (ADS)

Kravtsov, V. V.

2006-09-01

Peak metallicities of metal-rich populations of globular clusters (MRGCs) belonging to early-type galaxies and spheroidal subsystems of spiral galaxies (spheroids) of different mass fall within the somewhat conservative -0.7<=[Fe/H]<=-0.3 range. Indeed, if possible age effects are taken into account, this metallicity range might become smaller. Irregular galaxies such as the Large Magellanic Cloud (LMC), with longer timescales of formation and lower star formation (SF) efficiency, do not contain old MRGCs with [Fe/H]>-1.0, but they are observed to form populations of young/intermediate-age massive star clusters (MSCs) with masses exceeding 104 Msolar. Their formation is widely believed to be an accidental process fully dependent on external factors. From the analysis of available data on the populations and their hosts, including intermediate-age populous star clusters in the LMC, we find that their most probable mean metallicities fall within -0.7<=[Fe/H]<=-0.3, as the peak metallicities of MRGCs do, irrespective of signs of interaction. Moreover, both the disk giant metallicity distribution function (MDF) in the LMC and the MDFs for old giants in the halos of massive spheroids exhibit a significant increase toward [Fe/H]~-0.5. That is in agreement with a correlation found between SF activity in galaxies and their metallicity. The formation of both the old MRGCs in spheroids and MSC populations in irregular galaxies probably occurs at approximately the same stage of the host galaxies' chemical evolution and is related to the essentially increased SF activity in the hosts around the same metallicity that is achieved very early in massive spheroids, later in lower mass spheroids, and much later in irregular galaxies. Changes in the interstellar dust, particularly in elemental abundances in dust grains and in the mass distribution function of the grains, may be among the factors regulating star and MSC formation activity in galaxies. Strong interactions and mergers affecting the MSC formation presumably play an additional role, although they can substantially intensify the internally regulated MSC formation process. Several implications of our suggestions are briefly discussed.

Mechanical Player Load™ using trunk-mounted accelerometry in football: Is it a reliable, task- and player-specific observation?

PubMed

Barreira, Paulo; Robinson, Mark A; Drust, Barry; Nedergaard, Niels; Raja Azidin, Raja Mohammed Firhad; Vanrenterghem, Jos

2017-09-01

The aim of the present study was to examine reliability and construct convergent validity of Player Load™ (PL) from trunk-mounted accelerometry, expressed as a cumulative measure and an intensity measure (PL · min - 1 ). Fifteen male participants twice performed an overground football match simulation that included four different multidirectional football actions (jog, side cut, stride and sprint) whilst wearing a trunk-mounted accelerometer inbuilt in a global positioning system unit. Results showed a moderate-to-high reliability as indicated by the intra-class correlation coefficient (0.806-0.949) and limits of agreement. Convergent validity analysis showed considerable between-participant variation (coefficient of variation range 14.5-24.5%), which was not explained from participant demographics despite a negative association with body height for the stride task. Between-task variations generally showed a moderate correlation between ranking of participants for PL (0.593-0.764) and PL · min - 1 (0.282-0.736). It was concluded that monitoring PL ® in football multidirectional actions presents moderate-to-high reliability, that between-participant variability most likely relies on the individual's locomotive skills and not their anthropometrics, and that the intensity of a task expressed by PL · min - 1 is largely related to the running velocity of the task.

Microstructure optimization for high-performance PrBa0.5Sr0.5Co1.5Fe0.5O5+δ-La2NiO4+δ core-shell cathode of solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Li, Jin; Qiu, Peng; Xia, Meng; Jia, Lichao; Chi, Bo; Pu, Jian; Li, Jian

2018-03-01

Four PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF)-La2NiO4+δ (LN) core-shell cathodes, designated as PL-0, PL-1, PL-3 and PL-5, are prepared by infiltrating LN solution into PBSCF scaffold, and they are investigated in terms of the effect of LN thickness on their electrochemical performance. PL-3 with a continuous LN coating of a moderate average thickness (∼9 nm) demonstrates the lowest initial polarization resistance (0.51 Ω cm2) and highest power density (0.71 W cm-2) among all the cathodes. Polarized at 400 mA cm-2 and 700 °C for up to 40 h, the polarization resistance of all the prepared cathodes increases to approach a stable level after early stage decrease due to current activation, and PL-3 exhibits a slower average rate of performance degradation (25%). The electrochemical performance improvement is mainly attributed to that LN has a relatively high oxygen surface exchange coefficient and continuous LN coating depresses Sr segregation at PBSCF/LN interface.

Strong Photoluminescence Enhancement of Silicon Oxycarbide through Defect Engineering

PubMed Central

Ford, Brian; Tabassum, Natasha; Nikas, Vasileios; Gallis, Spyros

2017-01-01

The following study focuses on the photoluminescence (PL) enhancement of chemically synthesized silicon oxycarbide (SiCxOy) thin films and nanowires through defect engineering via post-deposition passivation treatments. SiCxOy materials were deposited via thermal chemical vapor deposition (TCVD), and exhibit strong white light emission at room-temperature. Post-deposition passivation treatments were carried out using oxygen, nitrogen, and forming gas (FG, 5% H2, 95% N2) ambients, modifying the observed white light emission. The observed white luminescence was found to be inversely related to the carbonyl (C=O) bond density present in the films. The peak-to-peak PL was enhanced ~18 and ~17 times for, respectively, the two SiCxOy matrices, oxygen-rich and carbon-rich SiCxOy, via post-deposition passivations. Through a combinational and systematic Fourier transform infrared spectroscopy (FTIR) and PL study, it was revealed that proper tailoring of the passivations reduces the carbonyl bond density by a factor of ~2.2, corresponding to a PL enhancement of ~50 times. Furthermore, the temperature-dependent and temperature-dependent time resolved PL (TDPL and TD-TRPL) behaviors of the nitrogen and forming gas passivated SiCxOy thin films were investigated to acquire further insight into the ramifications of the passivation on the carbonyl/dangling bond density and PL yield. PMID:28772802

A Round-Efficient Authenticated Key Agreement Scheme Based on Extended Chaotic Maps for Group Cloud Meeting

PubMed Central

Lee, Tian-Fu; Wang, Zeng-Bo

2017-01-01

The security is a critical issue for business purposes. For example, the cloud meeting must consider strong security to maintain the communication privacy. Considering the scenario with cloud meeting, we apply extended chaotic map to present passwordless group authentication key agreement, termed as Passwordless Group Authentication Key Agreement (PL-GAKA). PL-GAKA improves the computation efficiency for the simple group password-based authenticated key agreement (SGPAKE) proposed by Lee et al. in terms of computing the session key. Since the extended chaotic map has equivalent security level to the Diffie–Hellman key exchange scheme applied by SGPAKE, the security of PL-GAKA is not sacrificed when improving the computation efficiency. Moreover, PL-GAKA is a passwordless scheme, so the password maintenance is not necessary. Short-term authentication is considered, hence the communication security is stronger than other protocols by dynamically generating session key in each cloud meeting. In our analysis, we first prove that each meeting member can get the correct information during the meeting. We analyze common security issues for the proposed PL-GAKA in terms of session key security, mutual authentication, perfect forward security, and data integrity. Moreover, we also demonstrate that communicating in PL-GAKA is secure when suffering replay attacks, impersonation attacks, privileged insider attacks, and stolen-verifier attacks. Eventually, an overall comparison is given to show the performance between PL-GAKA, SGPAKE and related solutions. PMID:29207509

Absence of micronucleus formation in CHO-K1 cells cultivated in platelet lysate enriched medium.

PubMed

Bernardi, Martina; Adami, Valentina; Albiero, Elena; Madeo, Domenico; Rodeghiero, Francesco; Astori, Giuseppe

2014-03-01

Human platelet lysate (PL) represents an effective substitute of fetal bovine serum (FBS) for mesenchymal stromal cell (MSC) cultivation. Compared to FBS, PL favors MSC proliferation significantly shortening the population doubling time and avoiding the risks related to the use of animal derivatives. Growth factors contained in the platelets are released upon platelet disruption following freezing/thawing cycles or as we have recently described by using ultrasound. We have investigated whether the increased cell proliferation achieved by using PL could induce mitotic stress and whether the potential formation of free radicals during PL production by ultrasound could cause chromosomal instability in mammalian cells. We have applied an image analysis assisted high content screening (HCS) in vitro micronucleus assay in the Chinese Hamster Ovarian K1 (CHO-K1) rodent mammalian cell line. PL was produced by sonication; for the micronucleus assay, CHO-K1 cells were exposed to increasing concentrations of PL. Cytokinesis was blocked by cytochalasin B, nuclei were stained with bisbenzimide and images were acquired and analyzed automatically using an HCS system, both with a 20× and a 10× objective. Our results suggest that growth stimulus induced by the use of PL did not significantly increase micronucleus formation in CHO-K1 cells compared to negative control. Micronucleus testing in conjunction with HCS could represent a valid tool to evaluate the safety of ancillary materials used in the production of cell-based medicinal products. Copyright © 2013 Elsevier GmbH. All rights reserved.

Comparison of allogeneic platelet lysate and fetal bovine serum for in vitro expansion of equine bone marrow-derived mesenchymal stem cells.

PubMed

Seo, Jong-pil; Tsuzuki, Nao; Haneda, Shingo; Yamada, Kazutaka; Furuoka, Hidefumi; Tabata, Yasuhiko; Sasaki, Naoki

2013-10-01

Mesenchymal stem cells (MSCs) are promising candidates for cell-based therapy and tissue engineering approaches. Fetal bovine serum (FBS) is commonly used for in vitro MSC expansion; however, the use of FBS may be associated with ethical, scientific, and safety issues. This study aimed to compare the ability of allogeneic platelet lysate (PL) and FBS to cause equine bone marrow-derived MSC expansion. MSCs were isolated from bone marrow aspirate in media supplemented with either PL or FBS, and cell proliferation properties and characteristics were examined. There were no significant differences in MSC yield, colony-forming unit-fibroblast (CFU-F) assay, and population doubling time between PL and FBS cultures. In addition, both PL-MSCs and FBS-MSCs showed similar results in term of ALP staining, osteogenic differentiation, and RT-PCR, although there were subtle differences in morphology, growth pattern, and adhesive properties. These results suggest that PL is a suitable alternative to FBS for use in equine MSC expansion, without the problems related to FBS use. Published by Elsevier India Pvt Ltd.

Human platelet lysate successfully promotes proliferation and subsequent chondrogenic differentiation of adipose-derived stem cells: a comparison with articular chondrocytes.

PubMed

Hildner, F; Eder, M J; Hofer, K; Aberl, J; Redl, H; van Griensven, M; Gabriel, C; Peterbauer-Scherb, A

2015-07-01

Fetal calf serum (FCS) bears a potential risk for carrying diseases and eliciting immune reactions. Nevertheless, it still represents the gold standard as medium supplement in cell culture. In the present study, human platelet lysate (PL) was tested as an alternative to FCS for the expansion and subsequent chondrogenic differentiation of human adipose-derived stem cells (ASCs). ASCs were expanded with 10% FCS (group F) or 5% PL (group P). Subsequently, three-dimensional (3D) micromass pellets were created and cultured for 5 weeks in chondrogenic differentiation medium. Additionally, the de- and redifferentiation potential of human articular chondrocytes (HACs) was evaluated and compared to ASCs. Both HACs and ASCs cultured with PL showed strongly enhanced proliferation rates. Redifferentiation of HACs was possible for cells expanded up to 3.3 population doublings (PD). At this stage, PL-expanded HACs demonstrated better redifferentiation potential than FCS-expanded cells. ASCs could also be differentiated following extended passaging. Glycosaminoglycan (GAG) quantification and qRT-PCR of 10 cartilage related markers demonstrated a tendency for increased chondrogenic differentiation of PL-expanded ASCs compared to cells expanded with FCS. Histologically, collagen type II but also collagen type X was mainly present in group P. The present study demonstrates that PL strongly induces proliferation of ASCs, while the chondrogenic differentiation potential is retained. HACs also showed enhanced proliferation and even better redifferentiation when previously expanded with PL. This suggests that PL is superior to FCS as a supplement for the expansion of ASCs and HACs, particularly with regard to chondrogenic (re)differentiation. Copyright © 2013 John Wiley & Sons, Ltd.

[Anti-synthetase syndrome: anti-PL-7, anti-PL-12 and anti-EJ].

PubMed

Souza, Fernando Henrique Carlos de; Cruellas, Marcela Gran Pina; Levy-Neto, Mauricio; Shinjo, Samuel Katsuyuki

2013-08-01

Due to the scarcity of studies in the literature, we conducted an analysis of a series of patients with the anti-PL-7, PL-12 and EJ types of antisynthetase syndrome (ASS). We conducted a retrospective cohort study of 20 patients with ASS (8 with anti-PL-7, 6 with PL-12, 6 with EJ) monitored in our department between 1982 and 2012. The mean patient age at disease onset was 38.5 ± 12.9 years, and the disease duration was 4.5 ± 6.4 years. Of all the patients, 70% were white and 85% were female. Constitutional symptoms occurred in 90% of cases. All patients presented objective muscle weakness in the limbs; in addition, 30% were bedridden and 65% demonstrated high dysphagia at diagnosis. Joint and pulmonary involvement and Raynaud's phenomenon occurred in 50%, 40% and 65% of cases, respectively, with more than half of the patients presenting incipient pneumopathy, ground-glass opacity and/or pulmonary fibrosis. There were no cases of neurological and/or cardiac involvement. All patients received prednisone or other immunosuppressants depending on tolerance, side effects and/or disease refractoriness. Importantly, patients with the anti-EJ type of ASS demonstrated higher rates of recurrence. Two patients died during follow-up, and 1 patient had breast cancer at the time of diagnosis. ASS (anti-PL-7, PL-12 and EJ) was found to predominantly affect white women. Although the autoantibodies described in the present study are more related to pulmonary than joint involvement, our patients showed a significant percentage of both types of involvement and a high percentage of myopathy. We also observed a low mortality rate.

Photoluminescence probing of interface evolution with annealing in InGa(N)As/GaAs single quantum wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao, Jun, E-mail: jshao@mail.sitp.ac.cn; Qi, Zhen; Zhu, Liang

The effects of thermal annealing on the interfaces of InGa(N)As/GaAs single quantum wells (SQWs) are investigated by excitation-, temperature-, and magnetic field-dependent photoluminescence (PL). The annealing at 750 °C results in more significant blueshift and narrowing to the PL peak than that at 600 °C. Each of the PL spectra can be reproduced with two PL components: (i) the low-energy component (LE) keeps energetically unchanged, while the high-energy component (HE) moves up with excitation and shows at higher energy for the In{sub 0.375}Ga{sub 0.625}As/GaAs but crosses over with the LE at a medium excitation power for the In{sub 0.375}Ga{sub 0.625}N{sub 0.012}As{sub 0.988}/GaAsmore » SQWs. The HE is broader than the corresponding LE, the annealing at 750 °C narrows the LE and HE and shrinks their energetic separation; (ii) the PL components are excitonic, and the InGaNAs shows slightly enhanced excitonic effects relative to the InGaAs SQW; (iii) no typical S-shape evolution of PL energy with temperature is detectable, and similar blueshift and narrowing are identified for the same annealing. The phenomena are mainly from the interfacial processes. Annealing improves the intralayer quality, enhances the interfacial In-Ga interdiffusion, and reduces the interfacial fluctuation. The interfacial interdiffusion does not change obviously by the small N content and hence similar PL-component narrowing and blueshift are observed for the SQWs after a nominally identical annealing. Comparison with previous studies is made and the PL measurements under different conditions are shown to be effective for probing the interfacial evolution in QWs.« less

Wolf-Rayet spin at low metallicity and its implication for black hole formation channels

NASA Astrophysics Data System (ADS)

Vink, Jorick S.; Harries, Tim J.

2017-07-01

Context. The spin of Wolf-Rayet (WR) stars at low metallicity (Z) is most relevant for our understanding of gravitational wave sources, such as GW 150914, and of the incidence of long-duration gamma-ray bursts (GRBs). Two scenarios have been suggested for both phenomena: one of them involves rapid rotation and quasi-chemical homogeneous evolution (CHE) and the other invokes classical evolution through mass loss in single and binary systems. Aims: The stellar spin of WR stars might enable us to test these two scenarios. In order to obtain empirical constraints on black hole progenitor spin we infer wind asymmetries in all 12 known WR stars in the Small Magellanic Cloud (SMC) at Z = 1 / 5 Z⊙ and within a significantly enlarged sample of single and binary WR stars in the Large Magellanic Cloud (LMC at Z = 1 / 2 Z⊙), thereby tripling the sample of Vink from 2007. This brings the total LMC sample to 39, making it appropriate for comparison to the Galactic sample. Methods: We measured WR wind asymmetries with VLT-FORS linear spectropolarimetry, a tool that is uniquely poised to perform such tasks in extragalactic environments. Results: We report the detection of new line effects in the LMC WN star BAT99-43 and the WC star BAT99-70, along with the well-known WR LBV HD 5980 in the SMC, which might be undergoing a chemically homogeneous evolution. With the previous reported line effects in the late-type WNL (Ofpe/WN9) objects BAT99-22 and BAT99-33, this brings the total LMC WR sample to four, I.e. a frequency of 10%. Perhaps surprisingly, the incidence of line effects amongst low Z WR stars is not found to be any higher than amongst the Galactic WR sample, challenging the rotationally induced CHE model. Conclusions: As WR mass loss is likely Z-dependent, our Magellanic Cloud line-effect WR stars may maintain their surface rotation and fulfill the basic conditions for producing long GRBs, both via the classical post-red supergiant or luminous blue variable channel, or resulting from CHE due to physics specific to very massive stars.

The effects of platelet lysate patches on the activity of tendon-derived cells.

PubMed

Costa-Almeida, Raquel; Franco, Albina R; Pesqueira, Tamagno; Oliveira, Mariana B; Babo, Pedro S; Leonor, Isabel B; Mano, João F; Reis, Rui L; Gomes, Manuela E

2018-03-01

Platelet-derived biomaterials are widely explored as cost-effective sources of therapeutic factors, holding a strong potential for endogenous regenerative medicine. Particularly for tendon repair, treatment approaches that shift the injury environment are explored to accelerate tendon regeneration. Herein, genipin-crosslinked platelet lysate (PL) patches are proposed for the delivery of human-derived therapeutic factors in patch augmentation strategies aiming at tendon repair. Developed PL patches exhibited a controlled release profile of PL proteins, including bFGF and PDGF-BB. Additionally, PL patches exhibited an antibacterial effect by preventing the adhesion, proliferation and biofilm formation by S. aureus, a common pathogen in orthopaedic surgical site infections. Furthermore, these patches supported the activity of human tendon-derived cells (hTDCs). Cells were able to proliferate over time and an up-regulation of tenogenic genes (SCX, COL1A1 and TNC) was observed, suggesting that PL patches may modify the behavior of hTDCs. Accordingly, hTDCs deposited tendon-related extracellular matrix proteins, namely collagen type I and tenascin C. In summary, PL patches can act as a reservoir of biomolecules derived from PL and support the activity of native tendon cells, being proposed as bioinstructive patches for tendon regeneration. Platelet-derived biomaterials hold great interest for the delivery of therapeutic factors for applications in endogenous regenerative medicine. In the particular case of tendon repair, patch augmentation strategies aiming at shifting the injury environment are explored to improve tendon regeneration. In this study, PL patches were developed with remarkable features, including the controlled release of growth factors and antibacterial efficacy. Remarkably, PL patches supported the activity of native tendon cells by up-regulating tenogenic genes and enabling the deposition of ECM proteins. This patch holds great potential towards simultaneously reducing post-implantation surgical site infections and promoting tendon regeneration for prospective in vivo applications. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Pl(17) is a novel gene independent of known downy mildew resistance genes in the cultivated sunflower (Helianthus annuus L.).

PubMed

Qi, L L; Long, Y M; Jan, C C; Ma, G J; Gulya, T J

2015-04-01

Pl 17, a novel downy mildew resistance gene independent of known downy mildew resistance genes in sunflowers, was genetically mapped to linkage group 4 of the sunflower genome. Downy mildew (DM), caused by Plasmopara halstedii (Farl.). Berl. et de Toni, is one of the serious sunflower diseases in the world due to its high virulence and the variability of the pathogen. DM resistance in the USDA inbred line, HA 458, has been shown to be effective against all virulent races of P. halstedii currently identified in the USA. To determine the chromosomal location of this resistance, 186 F 2:3 families derived from a cross of HA 458 with HA 234 were phenotyped for their resistance to race 734 of P. halstedii. The segregation ratio of the population supported that the resistance was controlled by a single dominant gene, Pl 17. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) primers were used to identify molecular markers linked to Pl 17. Bulked segregant analysis using 849 SSR markers located Pl 17 to linkage group (LG) 4, which is the first DM gene discovered in this linkage group. An F2 population of 186 individuals was screened with polymorphic SSR and SNP primers from LG4. Two flanking markers, SNP SFW04052 and SSR ORS963, delineated Pl 17 in an interval of 3.0 cM. The markers linked to Pl 17 were validated in a BC3 population. A search for the physical location of flanking markers in sunflower genome sequences revealed that the Pl 17 region had a recombination frequency of 0.59 Mb/cM, which was a fourfold higher recombination rate relative to the genomic average. This region can be considered amenable to molecular manipulation for further map-based cloning of Pl 17.

Application of U/Th and 40Ar/39Ar Dating to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic Site in Ardèche, France

PubMed Central

Michel, Véronique; Shen, Guanjun; Shen, Chuan-Chou; Wu, Chung-Che; Vérati, Chrystèle; Gallet, Sylvain; Moncel, Marie-Hélène; Combier, Jean; Khatib, Samir; Manetti, Michel

2013-01-01

Refined radio-isotopic dating techniques have been applied to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic site in France. Evidence of Levallois core technology appeared in level 4b in the middle of the sequence, became predominant in the upper horizons, and was best represented in uppermost level 1, making the site one of the oldest examples of Levallois technology. In our dating study, fourteen speleothem samples from levels 7, 6 and 5b, were U/Th-dated. Four pure calcite samples from the speleothem PL1 (levels 5b, 6) yield ages between 265 ± 4 (PL1-3) and 312 ± 15 (PL1-6) thousand years ago (ka). Three samples from the top of a second stalagmite, PL2, yield dates ranging from 288 ± 10 ka (PL2-1) to 298 ± 17 ka (PL2-3). Three samples from the base of PL2 (level 7) yield much younger U/Th dates between 267 and 283 ka. These dates show that the speleothems PL1 and PL2 are contemporaneous and formed during marine isotope stage (MIS) 9 and MIS 8. Volcanic minerals in level 2, the upper sequence, were dated by the 40Ar/39Ar method, giving a weighted mean of 302.9 ± 2.5 ka (2σ) and an inverse isochron age of 302.9 ± 5.9 ka (2σ). Both 40Ar/39Ar dating of volcanic sanidines and U/Th dating of relatively pure and dense cave calcites are known to be well established. The first parallel application of the two geochronometers to Orgnac 3 yields generally consistent results, which point to the reliability of the two methods. The difference between their age results is discussed. PMID:24349273

Application of U/Th and 40Ar/39Ar dating to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic site in Ardèche, France.

PubMed

Michel, Véronique; Shen, Guanjun; Shen, Chuan-Chou; Wu, Chung-Che; Vérati, Chrystèle; Gallet, Sylvain; Moncel, Marie-Hélène; Combier, Jean; Khatib, Samir; Manetti, Michel

2013-01-01

Refined radio-isotopic dating techniques have been applied to Orgnac 3, a Late Acheulean and Early Middle Palaeolithic site in France. Evidence of Levallois core technology appeared in level 4b in the middle of the sequence, became predominant in the upper horizons, and was best represented in uppermost level 1, making the site one of the oldest examples of Levallois technology. In our dating study, fourteen speleothem samples from levels 7, 6 and 5b, were U/Th-dated. Four pure calcite samples from the speleothem PL1 (levels 5b, 6) yield ages between 265 ± 4 (PL1-3) and 312 ± 15 (PL1-6) thousand years ago (ka). Three samples from the top of a second stalagmite, PL2, yield dates ranging from 288 ± 10 ka (PL2-1) to 298 ± 17 ka (PL2-3). Three samples from the base of PL2 (level 7) yield much younger U/Th dates between 267 and 283 ka. These dates show that the speleothems PL1 and PL2 are contemporaneous and formed during marine isotope stage (MIS) 9 and MIS 8. Volcanic minerals in level 2, the upper sequence, were dated by the (40)Ar/(39)Ar method, giving a weighted mean of 302.9 ± 2.5 ka (2σ) and an inverse isochron age of 302.9 ± 5.9 ka (2σ). Both (40)Ar/(39)Ar dating of volcanic sanidines and U/Th dating of relatively pure and dense cave calcites are known to be well established. The first parallel application of the two geochronometers to Orgnac 3 yields generally consistent results, which point to the reliability of the two methods. The difference between their age results is discussed.

Activity in prelimbic cortex is required for adjusting the anxiety response level during the elevated plus-maze retest.

PubMed

Stern, C A J; Do Monte, F H M; Gazarini, L; Carobrez, A P; Bertoglio, L J

2010-09-29

The prelimbic (PL) subregion of medial prefrontal cortex has been implicated in anxiety regulation. It is unknown, however, whether PL cortex also serves to fine-tuning the level of anxiety-related behavior exhibited on the next exposure to the same potentially threatening situation. To address this, we infused cobalt (1.0 mM) to temporarily inactivate the PL cortex during testing, post-testing or retesting in the elevated plus-maze (EPM). This protocol was chosen because it allowed us to concurrently investigate anxiety and the process of aversive learning and memory. PL cortex inactivation during the EPM testing increased the exploration of open-arms, substantiating its role in anxiety. PL cortex inactivation during the EPM retesting counteracted the further avoidance to open-arms exhibited by rats. Interestingly, as evidenced by min-by-min analysis, the cobalt-treated group behaved on EPM retesting as did the vehicle-treated group on EPM testing. This result may imply that activity in PL cortex is necessary for retrieving previously learned information that adjusts the anxiety response level on EPM retesting. Alternatively, a simple reduction in anxiety could explain the cobalt-induced increase in retest open-arms exploration. Neither test nor post-test PL cortex inactivation affected the further avoidance to open-arms observed on EPM retesting. To extend the investigation of PL cortex role in the regulation of open-arms avoidance, we infused other drugs prior to testing or retesting in the EPM. Antagonism of PL cortex adrenergic beta-1 receptors with atenolol (10 nmol), cholinergic muscarinic receptors with scopolamine (20 nmol) or glutamatergic N-methyl-d-aspartic acid (NMDA) receptors with AP5 (6.0 nmol) interfered with the level of open-arms exploration on testing, but not on retesting. Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Evaluating the distance between the femoral tunnel centers in anatomic double-bundle anterior cruciate ligament reconstruction using a computer simulation

PubMed Central

Tashiro, Yasutaka; Okazaki, Ken; Iwamoto, Yukihide

2015-01-01

Purpose We aimed to clarify the distance between the anteromedial (AM) bundle and posterolateral (PL) bundle tunnel-aperture centers by simulating the anatomical femoral tunnel placement during double-bundle anterior cruciate ligament reconstruction using 3-D computer-aided design models of the knee, in order to discuss the risk of tunnel overlap. Relationships between the AM to PL center distance, body height, and sex difference were also analyzed. Patients and methods The positions of the AM and PL tunnel centers were defined based on previous studies using the quadrant method, and were superimposed anatomically onto the 3-D computer-aided design knee models from 68 intact femurs. The distance between the tunnel centers was measured using the 3-D DICOM software package. The correlation between the AM–PL distance and the subject’s body height was assessed, and a cutoff height value for a higher risk of overlap of the AM and PL tunnel apertures was identified. Results The distance between the AM and PL centers was 10.2±0.6 mm in males and 9.4±0.5 mm in females (P<0.01). The AM–PL center distance demonstrated good correlation with body height in both males (r=0.66, P<0.01) and females (r=0.63, P<0.01). When 9 mm was defined as the critical distance between the tunnel centers to preserve a 2 mm bony bridge between the two tunnels, the cutoff value was calculated to be a height of 160 cm in males and 155 cm in females. Conclusion When AM and PL tunnels were placed anatomically in simulated double-bundle anterior cruciate ligament reconstruction, the distance between the two tunnel centers showed a strong positive correlation with body height. In cases with relatively short stature, the AM and PL tunnel apertures are considered to be at a higher risk of overlap when surgeons choose the double-bundle technique. PMID:26170727

Investigation of critical inter-related factors affecting the efficacy of pulsed light for inactivating clinically relevant bacterial pathogens.

PubMed

Farrell, H P; Garvey, M; Cormican, M; Laffey, J G; Rowan, N J

2010-05-01

To investigate critical electrical and biological factors governing the efficacy of pulsed light (PL) for the in vitro inactivation of bacteria isolated from the clinical environment. Development of this alternative PL decontamination approach is timely, as the incidence of health care-related infections remains unacceptably high. Predetermined cell numbers of clinically relevant Gram-positive and Gram-negative bacteria were inoculated separately on agar plates and were flashed with

GFP-Mutant Human Tau Transgenic Mice Develop Tauopathy Following CNS Injections of Alzheimer's Brain-Derived Pathological Tau or Synthetic Mutant Human Tau Fibrils.

PubMed

Gibbons, Garrett S; Banks, Rachel A; Kim, Bumjin; Xu, Hong; Changolkar, Lakshmi; Leight, Susan N; Riddle, Dawn M; Li, Chi; Gathagan, Ronald J; Brown, Hannah J; Zhang, Bin; Trojanowski, John Q; Lee, Virginia M-Y

2017-11-22

Neurodegenerative proteinopathies characterized by intracellular aggregates of tau proteins, termed tauopathies, include Alzheimer's disease (AD), frontotemporal lobar degeneration (FTLD) with tau pathology (FTLD-tau), and related disorders. Pathological tau proteins derived from human AD brains (AD-tau) act as proteopathic seeds that initiate the templated aggregation of soluble tau upon intracerebral injection into tau transgenic (Tg) and wild-type mice, thereby modeling human tau pathology. In this study, we found that aged Tg mice of both sexes expressing human tau proteins harboring a pathogenic P301L MAPT mutation labeled with green fluorescent protein (T40PL-GFP Tg mouse line) exhibited hyperphosphorylated tau mislocalized to the somatodentritic domain of neurons, but these mice did not develop de novo insoluble tau aggregates, which are characteristic of human AD and related tauopathies. However, intracerebral injections of either T40PL preformed fibrils (PFFs) or AD-tau seeds into T40PL-GFP mice induced abundant intraneuronal pathological inclusions of hyperphosphorylated T40PL-GFP. These injections of pathological tau resulted in the propagation of tau pathology from the injection site to neuroanatomically connected brain regions, and these tau inclusions consisted of both T40PL-GFP and WT endogenous mouse tau. Primary neurons cultured from the brains of neonatal T40PL-GFP mice provided an informative in vitro model for examining the uptake and localization of tau PFFs. These findings demonstrate the seeded aggregation of T40PL-GFP in vivo by synthetic PFFs and human AD-tau and the utility of this system to study the neuropathological spread of tau aggregates. SIGNIFICANCE STATEMENT The stereotypical spread of pathological tau protein aggregates have recently been attributed to the transmission of proteopathic seeds. Despite the extensive use of transgenic mouse models to investigate the propagation of tau pathology in vivo , details of the aggregation process such as the early seeding events leading to new tau pathology have remained elusive. This study validates the use of GFP-labeled tau expressed by neurons in vivo and in vitro as models for investigating mechanisms underlying the seeded transmission of tau pathology as well as tau-focused drug discovery to identify disease-modifying therapies for AD and related tauopathies. Copyright © 2017 the authors 0270-6474/17/3711485-10$15.00/0.

GFP-Mutant Human Tau Transgenic Mice Develop Tauopathy Following CNS Injections of Alzheimer's Brain-Derived Pathological Tau or Synthetic Mutant Human Tau Fibrils

PubMed Central

Banks, Rachel A.; Kim, Bumjin; Xu, Hong; Changolkar, Lakshmi; Leight, Susan N.; Riddle, Dawn M.; Li, Chi; Brown, Hannah J.; Zhang, Bin

2017-01-01

Neurodegenerative proteinopathies characterized by intracellular aggregates of tau proteins, termed tauopathies, include Alzheimer's disease (AD), frontotemporal lobar degeneration (FTLD) with tau pathology (FTLD-tau), and related disorders. Pathological tau proteins derived from human AD brains (AD-tau) act as proteopathic seeds that initiate the templated aggregation of soluble tau upon intracerebral injection into tau transgenic (Tg) and wild-type mice, thereby modeling human tau pathology. In this study, we found that aged Tg mice of both sexes expressing human tau proteins harboring a pathogenic P301L MAPT mutation labeled with green fluorescent protein (T40PL-GFP Tg mouse line) exhibited hyperphosphorylated tau mislocalized to the somatodentritic domain of neurons, but these mice did not develop de novo insoluble tau aggregates, which are characteristic of human AD and related tauopathies. However, intracerebral injections of either T40PL preformed fibrils (PFFs) or AD-tau seeds into T40PL-GFP mice induced abundant intraneuronal pathological inclusions of hyperphosphorylated T40PL-GFP. These injections of pathological tau resulted in the propagation of tau pathology from the injection site to neuroanatomically connected brain regions, and these tau inclusions consisted of both T40PL-GFP and WT endogenous mouse tau. Primary neurons cultured from the brains of neonatal T40PL-GFP mice provided an informative in vitro model for examining the uptake and localization of tau PFFs. These findings demonstrate the seeded aggregation of T40PL-GFP in vivo by synthetic PFFs and human AD-tau and the utility of this system to study the neuropathological spread of tau aggregates. SIGNIFICANCE STATEMENT The stereotypical spread of pathological tau protein aggregates have recently been attributed to the transmission of proteopathic seeds. Despite the extensive use of transgenic mouse models to investigate the propagation of tau pathology in vivo, details of the aggregation process such as the early seeding events leading to new tau pathology have remained elusive. This study validates the use of GFP-labeled tau expressed by neurons in vivo and in vitro as models for investigating mechanisms underlying the seeded transmission of tau pathology as well as tau-focused drug discovery to identify disease-modifying therapies for AD and related tauopathies. PMID:28986461

Transparently wrap-gated semiconductor nanowire arrays for studies of gate-controlled photoluminescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nylund, Gustav; Storm, Kristian; Torstensson, Henrik

2013-12-04

We present a technique to measure gate-controlled photoluminescence (PL) on arrays of semiconductor nanowire (NW) capacitors using a transparent film of Indium-Tin-Oxide (ITO) wrapping around the nanowires as the gate electrode. By tuning the wrap-gate voltage, it is possible to increase the PL peak intensity of an array of undoped InP NWs by more than an order of magnitude. The fine structure of the PL spectrum reveals three subpeaks whose relative peak intensities change with gate voltage. We interpret this as gate-controlled state-filling of luminescing quantum dot segments formed by zincblende stacking faults in the mainly wurtzite NW crystal structure.

Apparatus for determining past-service conditions and remaining life of thermal barrier coatings and components having such coatings

DOEpatents

Srivastava, Alok Mani; Setlur, Anant Achyut; Comanzo, Holly Ann; Devitt, John William; Ruud, James Anthony; Brewer, Luke Nathaniel

2004-05-04

An apparatus for determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating ("TBC") of the component comprises a radiation source that provides the exciting radiation to the TBC to excite a photoluminescent ("PL") material contained therein, a radiation detector for detecting radiation emitted by the PL material, and means for relating a characteristic of an emission spectrum of the PL material to the amount of a crystalline phase in the TBC, thereby inferring the past-service conditions or the remaining useful life of the component or the TBC.

Lipidomic approach to identify patterns in phospholipid profiles and define class differences in mammary epithelial and breast cancer cells.

PubMed

Dória, M Luísa; Cotrim, Zita; Macedo, Bárbara; Simões, Cláudia; Domingues, Pedro; Helguero, Luisa; Domingues, M Rosário

2012-06-01

Breast cancer is the leading cause of cancer-related deaths in women. Altered cellular functions of cancer cells lead to uncontrolled cellular growth and morphological changes. Cellular biomembranes are intimately involved in the regulation of cell signaling; however, they remain largely understudied. Phospholipids (PLs) are the main constituents of biological membranes and play important functional, structural and metabolic roles. The aim of this study was to establish if patterns in the PL profiles of mammary epithelial cells and breast cancer cells differ in relation to degree of differentiation and metastatic potential. For this purpose, PLs were analyzed using a lipidomic approach. In brief, PLs were extracted using Bligh and Dyer method, followed by a separation of PL classes by thin layer chromatography, and subsequent analysis by mass spectrometry (MS). Differences and similarities were found in the relative levels of PL content between mammary epithelial and breast cancer cells and between breast cancer cells with different levels of aggressiveness. When compared to the total PL content, phosphatidylcholine levels were reduced and lysophosphatydilcholines increased in the more aggressive cancer cells; while phosphatidylserine levels remained unchanged. MS analysis showed alterations in the classes of phosphatidylcholine, lysophosphatidylcholine, sphingomyelin, and phosphatidylinositides. In particular, the phosphatidylinositides, which are signaling molecules that affect proliferation, survival, and migration, showed dramatic alterations in their profile, where an increase of phosphatdylinositides saturated fatty acids chains and a decrease in C20 fatty acids in cancer cells compared with mammary epithelial cells was observed. At present, information about PL changes in cancer progression is lacking. Therefore, these data will be useful as a starting point to define possible PLs with prospective as biomarkers and disclose metabolic pathways with potential for therapy.

Femtosecond laser-induced size reduction and emission quantum yield enhancement of colloidal silicon nanocrystals: Effect of laser ablation time.

PubMed

Zhang, Yingxiong; Wu, Wenshun; Hao, Huilian; Shen, Wenzhong

2018-06-19

Colloidal silicon (Si) nanocrystals (NCs) with different sizes were successfully prepared by femtosecond laser ablation under different laser ablation time (LAT). The mean size decreases from 4.23 to 1.42 nm with increasing LAT from 30 to 120 min. In combination with structural characterization, temperature-dependent photoluminescence (PL), time-resolved PL, and PL excitation spectra, we attribute room temperature blue emissions peaked at 405 and 430 nm to the radiative recombination of electron-hole pairs via the oxygen deficient centers related to Si-C-H2 and Si-O-Si bonds of colloidal Si NCs prepared in 1-octene, respectively. In particular, the measured PL quantum yield of colloidal Si NCs has been enhanced significantly from 23.6% to 55.8% with prolonging LAT from 30 to 120 min. © 2018 IOP Publishing Ltd.

Electronic bandstructure of semiconductor dilute bismide structures

NASA Astrophysics Data System (ADS)

Erucar, T.; Nutku, F.; Donmez, O.; Erol, A.

2017-02-01

In this work electronic band structure of dilute bismide GaAs/GaAs1-xBix quantum well structures with 1.8% and 3.75% bismuth compositions have been investigated both experimentally and theoretically. Photoluminescence (PL) measurements reveal that effective bandgap of the samples decreases approximately 65 meV per bismuth concentration. Temperature dependence of the effective bandgap is obtained to be higher for the sample with higher bismuth concentration. Moreover, both asymmetric characteristic at the low energy tail of the PL and full width at half maximum (FWHM) of PL peak increase with increasing bismuth composition as a result of increased Bi related defects located above valence band (VB). In order to explain composition dependence of the effective bandgap quantitatively, valence band anti-crossing (VBAC) model is used. Bismuth composition and temperature dependence of effective bandgap in a quantum well structure is modeled by solving Schrödinger equation and compared with experimental PL data.

Pathological love: impulsivity, personality, and romantic relationship.

PubMed

Sophia, Eglacy C; Tavares, Hermano; Berti, Marina P; Pereira, Ana P; Lorena, Andrea; Mello, Cidália; Gorenstein, Clarice; Zilberman, Monica L

2009-05-01

Pathological love (PL)--behavior characterized by providing repetitive and uncontrolled care and attention to the partner in a romantic relationship--is a rarely studied condition, despite not being rare and causing suffering. This study aims at investigating impulsivity, personality, and characteristics related to the romantic relationship in this population. Eighty-nine individuals (50 with PL; 39 individuals with no psychiatric disorder) were compared regarding impulsivity, personality, type of attachment, satisfaction with romantic relationship, and love style. Individuals with PL have higher levels of impulsivity (P<.001; Barratt Impulsiveness Scale), higher self-transcendence, that is, are more unconventional and hold sense of communion with a wider reality (P<.001; Temperament and Character Inventory) and keep dissatisfactory romantic relationships (P<.001; Adapted Relationship Assessment Scale). Individuals with PL present personality traits and relationship aspects that must be taken into account in devising assessment and therapeutic strategies for this population.

Donor-acceptor pair recombination luminescence from monoclinic Cu{sub 2}SnS{sub 3} thin film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aihara, Naoya; Tanaka, Kunihiko, E-mail: tanaka@vos.nagaokaut.ac.jp; Uchiki, Hisao

2015-07-20

The defect levels in Cu{sub 2}SnS{sub 3} (CTS) were investigated using photoluminescence (PL) spectroscopy. A CTS thin film was prepared on a soda-lime glass/molybdenum substrate by thermal co-evaporation and sulfurization. The crystal structure was determined to be monoclinic, and the compositional ratios of Cu/Sn and S/Metal were determined to be 1.8 and 1.2, respectively. The photon energy of the PL spectra observed from the CTS thin film was lower than that previously reported. All fitted PL peaks were associated with defect related luminescence. The PL peaks observed at 0.843 and 0.867 eV were assigned to donor-acceptor pair recombination luminescence, the thermalmore » activation energies of which were determined to be 22.9 and 24.8 meV, respectively.« less

A novel approach to obtain highly intense self-activated photoluminescence emissions in hydroxyapatite nanoparticles

NASA Astrophysics Data System (ADS)

Machado, Thales R.; Sczancoski, Júlio C.; Beltrán-Mir, Héctor; Nogueira, Içamira C.; Li, Máximo S.; Andrés, Juan; Cordoncillo, Eloisa; Longo, Elson

2017-05-01

Defect-related photoluminescence (PL) in materials have attracted interest for applications including near ultraviolet (NUV) excitable light-emitting diodes and in biomedical field. In this paper, hydroxyapatite [Ca10(PO4)6(OH)2] nanorods with intense PL bands (bluish- and yellowish-white emissions) were obtained when excited under NUV radiation at room temperature. These nanoparticles were synthesized via chemical precipitation at 90 °C followed by distinct heat treatments temperatures (200-800 °C). Intense and broad emission profiles were achieved at 350 °C (380-750 nm) and 400 °C (380-800 nm). UV-Vis spectroscopy revealed band gap energies (5.58-5.78 eV) higher than the excitation energies ( 3.54 and 2.98 eV at 350 and 415 nm, respectively), confirming the contribution of defect energy levels within the forbidden zone for PL emissions. The structural features were characterized by X-ray diffraction, Rietveld refinement, thermogravimetric analysis, and Fourier transform infrared spectroscopy. By means of these techniques, the relation between structural order-disorder induced by defects, chemical reactions at both lattice and surface of the materials as well as the PL, without activator centers, was discussed in details.

Competition of the self-activated and Mn-related luminescence in ZnS single crystals

NASA Astrophysics Data System (ADS)

Bacherikov, Yu. Yu.; Vorona, I. P.; Markevich, I. V.; Korsunska, N. O.; Kurichka, R. V.

2018-06-01

The photoluminescence (PL) and photoluminescence excitation (PLE) spectra of ZnS single crystals thermally doped from ZnS/MnS mixture were studied at 300 and 77 K. PL spectra exhibit bands caused by Mn-related centers and centers of self-activated (SA) emission. Besides intrinsic maximum, a number of narrow peaks corresponded to Mn-related absorption are found in the PLE spectra of both SA and Mn-related emission. A redistribution of SA and Mn-related emission intensities is observed with temperature change. The mechanism of this phenomenon involving free hole trapping by MnZn and the possible position of a ground energy level of substitutional Mn are discussed.

Edades y metalicidades de cinco cúmulos estelares proyectados en dirección a la Nube Menor de Magallanes: implicaciones sobre los procesos de formación y evolución de estos sistemas

NASA Astrophysics Data System (ADS)

Piatti, A. E.; Santos, J. F. C.; Clariá, J. J.; Bica, E.; Sarajedini, A.; Geisler, D.

Washington photometry of the 5 star clusters Lindsay 32, Lindsay 38, Kron 28, Kron 44 and Lindsay 116 and their surrounding fields located towards the Small Magellanic Cloud (SMC) is presented for the first time. From the color-magnitude diagrams, cleaned from field stars contamination, the cluster and SMC field reddenings, ages and metallicities are determined. The ages - derived from the difference in the T1 magnitude betweem the giant clump and the Main Sequence turnoff point - vary between 2 and 6 Gyr, and the metallicities ([Fe/H]) between -1.65 and -1.10. Lindsay 116 is located closer to the Large Magellanic Cloud (LMC) than to the SMC and its fundamental parameters suggests a higher probability of belonging to the LMC. The results obtained in this work, combined with previous estimates of age and metallicity for other seven clusters, allow us to draw the following conclusions: (1) There does not exist an age-position relation in the SMC, but a age-metallicity one. (2) The chemical enrichment in the SMC has been very efficient during the last 5 Gyr. (3) The SMC clusters formation and evolution can be better represented by a bursting star formation process than by a continuum star formation mechanism.

The Long-term Light Curves of X-ray Binaries Contain Simultaneous Periodic and Random Components

NASA Technical Reports Server (NTRS)

White, Nicholas E. (Technical Monitor); Boyd, Patricia T.; Smale, Alan P.

2002-01-01

LMC X-3 and Cyg X-2 show large amplitude X-ray fluctuations that have been attributed to a warped accretion disk. Cyg X-3 displays high amplitude, apparently non-periodic oscillations. We reanalyze these systems using RXTE ASM data and time-frequency decomposition techniques. We find that the long-term variations in Cyg X-2 can be completely characterized by excursions whose durations are integer multiples of the orbital period, including one essentially identical to the reported "period" of 78 days. Cyg X-3 can be characterized in terms of integer multiples of a 71-day fundamental period unrelated to the 4.8 day orbital period, but suggestively close to the approximately equal to greater than 60 day reported precession period of the relativistic jet inferred from recent radio observations. The long-term excursions of LMC X-3 are related to each other by rational fractions, suggesting the characteristic time scale is 10.594 days, shorter than any observed excursion to date. We explore the phase space evolution of the light curves using a natural embedding and find that all three systems possess two rotation centers that organize the phase space trajectories, one of low luminosity and the other of high luminosity. The implications of this repeatable behavior on generic models of accretion disk dynamics and mass transfer variability are explored.

Development of the pulmonary surfactant system in two oviparous vertebrates.

PubMed

Johnston, S D; Orgeig, S; Lopatko, O V; Daniels, C B

2000-02-01

In birds and oviparous reptiles, hatching is often a lengthy and exhausting process, which commences with pipping followed by lung clearance and pulmonary ventilation. We examined the composition of pulmonary surfactant in the developing lungs of the chicken, Gallus gallus, and of the bearded dragon, Pogona vitticeps. Lung tissue was collected from chicken embryos at days 14, 16, 18 (prepipped), and 20 (postpipped) of incubation and from 1 day and 3 wk posthatch and adult animals. In chickens, surfactant protein A mRNA was detected using Northern blot analysis in lung tissue at all stages sampled, appearing relatively earlier in development compared with placental mammals. Chickens were lavaged at days 16, 18, and 20 of incubation and 1 day posthatch, whereas bearded dragons were lavaged at day 55, days 57-60 (postpipped), and days 58-61 (posthatched). In both species, total phospholipid (PL) from the lavage increased throughout incubation. Disaturated PL (DSP) was not measurable before 16 days of incubation in the chick embryo nor before 55 days in bearded dragons. However, the percentage of DSP/PL increased markedly throughout late development in both species. Because cholesterol (Chol) remained unchanged, the Chol/PL and Chol/DSP ratios decreased in both species. Thus the Chol and PL components are differentially regulated. The lizard surfactant system develops and matures over a relatively shorter time than that of birds and mammals. This probably reflects the highly precocial nature of hatchling reptiles.

Impact of extended defects on recombination in CdTe heterostructures grown by molecular beam epitaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaunbrecher, Katherine N.; National Renewable Energy Laboratory, Golden, Colorado 80401; Kuciauskas, Darius

Heterostructures with CdTe and CdTe{sub 1-x}Se{sub x} (x ∼ 0.01) absorbers between two wider-band-gap Cd{sub 1-x}Mg{sub x}Te barriers (x ∼ 0.25–0.3) were grown by molecular beam epitaxy to study carrier generation and recombination in bulk materials with passivated interfaces. Using a combination of confocal photoluminescence (PL), time-resolved PL, and low-temperature PL emission spectroscopy, two extended defect types were identified and the impact of these defects on charge-carrier recombination was analyzed. The dominant defects identified by confocal PL were dislocations in samples grown on (211)B CdTe substrates and crystallographic twinning-related defects in samples on (100)-oriented InSb substrates. Low-temperature PL shows that twin-related defects have amore » zero-phonon energy of 1.460 eV and a Huang-Rhys factor of 1.50, while dislocation-dominated samples have a 1.473-eV zero-phonon energy and a Huang-Rhys factor of 1.22. The charge carrier diffusion length near both types of defects is ∼6 μm, suggesting that recombination is limited by diffusion dynamics. For heterostructures with a low concentration of extended defects, the bulk lifetime was determined to be 2.2 μs with an interface recombination velocity of 160 cm/s and an estimated radiative lifetime of 91 μs.« less

VizieR Online Data Catalog: Early-type EBs with intermediate orbital periods (Moe+, 2015)

NASA Astrophysics Data System (ADS)

Moe, M.; Di Stefano, R.

2017-09-01

In this study, we select the NB~96000 systems in the OGLE-I catalog (Udalski et al. 2008AcA....58...89U) with mean magnitudes 16.0

Large Magellanic Cloud Distance and Structure from Near-Infrared Red Clump Observations

NASA Astrophysics Data System (ADS)

Koerwer, Joel F.

2009-07-01

We have applied the Infrared Survey Facility Magellanic Clouds Point-Source Catalog to the mapping of the red clump (RC) distance modulus across the Large Magellanic Cloud (LMC). Using the J- (1.25 μm) and H- (1.63 μm) band data to derive a reddening free luminosity function and a theoretical RC absolute magnitude from stellar evolution libraries, we estimate a distance modulus to the LMC of μ = 18.54 ± 0.06. The best fitting plane inclination, i, and the position angle of the line of nodes, phi, have little dependence on the assumed RC absolute magnitude; we find i = 23fdg5 ± 0fdg4 and phi = 154fdg6 ± 1fdg2. It was also noted that many fields included a significant asymptotic giant branch bump population that must be accounted for.

Far UV Observations of Interstellar Shocks

NASA Technical Reports Server (NTRS)

Raymond, John C.

1998-01-01

This grant covered analysis of Hopkins Ultraviolet Telescope data from the Astro-2 mission. The proposed research was aimed primarily at SNR shock waves, but the ASTRO-2 GO program was intended to make the GOs part of the instrument teams. The grant therefore covered extensive travel to Marshall Space Flight Center for mission simulations and the mission itself. In keeping with the unique nature of the ASTRO-2 GO program, I participated actively in the instrument team's investigations of HH objects and cataclysmic variables. Over the course of the Astro-2 mission, we obtained good observations of the supernova remnants SN1006 (1 position), Vela (3 positions), the Cygnus Loop (7 positions) and 0519-69 in the LMC (1 position) as part of this GI program, along with Puppis A (1 position), Vela (1 position), the Cygnus Loop (7 positions) and the Schweizer- Middleditch star (HUT PI program on SNRS). We also observed the Herbig-Haro object HH2 and about a dozen cataclysmic variables, including magnetic systems and dwarf novae. This GI grant covered modest travel for data analysis. We anticipate submitting papers on the non-radiative shock in northern Cygnus Loop, on the LMC Balmer-dominated remnant LMC 0519-69, on the radiative shocks in the Eastern Cygnus Loop (the XA region), and on the cataclysmic variable YZ Cnc over the course of the coming year. We have obtained extensive supporting data from ground-based telescopes for the Cygnus Loop spectra.

MASSCLEANage—Stellar Cluster Ages from Integrated Colors

NASA Astrophysics Data System (ADS)

Popescu, Bogdan; Hanson, M. M.

2010-11-01

We present the recently updated and expanded MASSCLEANcolors, a database of 70 million Monte Carlo models selected to match the properties (metallicity, ages, and masses) of stellar clusters found in the Large Magellanic Cloud (LMC). This database shows the rather extreme and non-Gaussian distribution of integrated colors and magnitudes expected with different cluster age and mass and the enormous age degeneracy of integrated colors when mass is unknown. This degeneracy could lead to catastrophic failures in estimating age with standard simple stellar population models, particularly if most of the clusters are of intermediate or low mass, like in the LMC. Utilizing the MASSCLEANcolors database, we have developed MASSCLEANage, a statistical inference package which assigns the most likely age and mass (solved simultaneously) to a cluster based only on its integrated broadband photometric properties. Finally, we use MASSCLEANage to derive the age and mass of LMC clusters based on integrated photometry alone. First, we compare our cluster ages against those obtained for the same seven clusters using more accurate integrated spectroscopy. We find improved agreement with the integrated spectroscopy ages over the original photometric ages. A close examination of our results demonstrates the necessity of solving simultaneously for mass and age to reduce degeneracies in the cluster ages derived via integrated colors. We then selected an additional subset of 30 photometric clusters with previously well-constrained ages and independently derive their age using the MASSCLEANage with the same photometry with very good agreement. The MASSCLEANage program is freely available under GNU General Public License.

Active Luminous Blue Variables in the Large Magellanic Cloud

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walborn, Nolan R.; Gamen, Roberto C.; Lajús, Eduardo Fernández

We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca ii] emission lines, as its spectralmore » type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.« less

Active Luminous Blue Variables in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Walborn, Nolan R.; Gamen, Roberto C.; Morrell, Nidia I.; Barbá, Rodolfo H.; Fernández Lajús, Eduardo; Angeloni, Rodolfo

2017-07-01

We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca II] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.

Information-Theoretical Complexity Analysis of Selected Elementary Chemical Reactions

NASA Astrophysics Data System (ADS)

Molina-Espíritu, M.; Esquivel, R. O.; Dehesa, J. S.

We investigate the complexity of selected elementary chemical reactions (namely, the hydrogenic-abstraction reaction and the identity SN2 exchange reaction) by means of the following single and composite information-theoretic measures: disequilibrium (D), exponential entropy(L), Fisher information (I), power entropy (J), I-D, D-L and I-J planes and Fisher-Shannon (FS) and Lopez-Mancini-Calbet (LMC) shape complexities. These quantities, which are functionals of the one-particle density, are computed in both position (r) and momentum (p) spaces. The analysis revealed that the chemically significant regions of these reactions can be identified through most of the single information-theoretic measures and the two-component planes, not only the ones which are commonly revealed by the energy, such as the reactant/product (R/P) and the transition state (TS), but also those that are not present in the energy profile such as the bond cleavage energy region (BCER), the bond breaking/forming regions (B-B/F) and the charge transfer process (CT). The analysis of the complexities shows that the energy profile of the abstraction reaction bears the same information-theoretical features of the LMC and FS measures, however for the identity SN2 exchange reaction does not hold a simple behavior with respect to the LMC and FS measures. Most of the chemical features of interest (BCER, B-B/F and CT) are only revealed when particular information-theoretic aspects of localizability (L or J), uniformity (D) and disorder (I) are considered.

Quantitative Analysis of Carbon Flow into Photosynthetic Products Functioning as Carbon Storage in the Marine Coccolithophore, Emiliania huxleyi.

PubMed

Tsuji, Yoshinori; Yamazaki, Masatoshi; Suzuki, Iwane; Shiraiwa, Yoshihiro

2015-08-01

The bloom-forming coccolithophore Emiliania huxleyi (Haptophyta) is a dominant marine phytoplankton, cells of which are covered with calcareous plates (coccoliths). E. huxleyi produces unique lipids of C37-C40 long-chain ketones (alkenones) with two to four trans-unsaturated bonds, β-glucan (but not α-glucan) and acid polysaccharide (AP) associated with the morphogenesis of CaCO3 crystals in coccoliths. Despite such unique features, there is no detailed information on the patterns of carbon allocation into these compounds. Therefore, we performed quantitative estimation of carbon flow into various macromolecular products by conducting (14)C-radiotracer experiments using NaH(14)CO3 as a substrate. Photosynthetic (14)C incorporation into low molecular-mass compounds (LMC), extracellular AP, alkenones, and total lipids except alkenones was estimated to be 35, 13, 17, and 25 % of total (14)C fixation in logarithmic growth phase cells and 33, 19, 18, and 18 % in stationary growth phase cells, respectively. However, less than 1 % of (14)C was incorporated into β-glucan in both cells. (14)C-mannitol occupied ca. 5 % of total fixed (14)C as the most dominant LMC product. Levels of all (14)C compounds decreased in the dark. Therefore, alkenones and LMC (including mannitol), but not β-glucan, function in carbon/energy storage in E. huxleyi, irrespective of the growth phase. Compared with other algae, the low carbon flux into β-glucan is a unique feature of carbon metabolism in E. huxelyi.

Optical characterization of single-crystal diamond grown by DC arc plasma jet CVD

NASA Astrophysics Data System (ADS)

Hei, Li-fu; Zhao, Yun; Wei, Jun-jun; Liu, Jin-long; Li, Cheng-ming; Lü, Fan-xiu

2017-12-01

Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition (CVD) were examined using a low-temperature photoluminescence (PL) technique. The results show that most of the nitrogen-vacancy (NV) complexes are present as NV- centers, although some H2 and H3 centers and B-aggregates are also present in the single-crystal diamond because of nitrogen aggregation resulting from high N2 incorporation and the high mobility of vacancies under growth temperatures of 950-1000°C. Furthermore, emissions of radiation-induced defects were also detected at 389, 467.5, 550, and 588.6 nm in the PL spectra. The reason for the formation of these radiation-induced defects is not clear. Although a Ni-based alloy was used during the diamond growth, Ni-related emissions were not detected in the PL spectra. In addition, the silicon-vacancy (Si-V)-related emission line at 737 nm, which has been observed in the spectra of many previously reported microwave plasma chemical vapor deposition (MPCVD) synthetic diamonds, was absent in the PL spectra of the single-crystal diamond prepared in this work. The high density of NV- centers, along with the absence of Ni-related defects and Si-V centers, makes the single-crystal diamond grown by DC arc plasma jet CVD a promising material for applications in quantum computing.

Prefrontal single-unit firing associated with deficient extinction in mice

PubMed Central

Fitzgerald, Paul J; Whittle, Nigel; Flynn, Shaun M; Graybeal, Carolyn; Pinard, Courtney; Gunduz-Cinar, Ozge; Kravitz, Alexxai; Singewald, Nicolas; Holmes, Andrew

2014-01-01

The neural circuitry mediating fear extinction has been increasingly well studied and delineated. The rodent infralimbic subregion (IL) of the ventromedial prefrontal cortex (vmPFC) has been found to promote extinction, whereas the prelimbic cortex (PL) demonstrates an opposing, pro-fear, function. Studies employing in vivo electrophysiological recordings have observed that while increased IL single-unit firing and bursting predicts robust extinction retrieval, increased PL firing can correlate with sustained fear and poor extinction. These relationships between single-unit firing and extinction do not hold under all experimental conditions, however. In the current study, we further investigated the relationship between vmPFC and PL single-unit firing and extinction using inbred mouse models of intact (C57BL/6J, B6) and deficient (129S1/SvImJ, S1) extinction strains. Simultaneous single-unit recordings were made in the PL and vmPFC (encompassing IL) as B6 and S1 mice performed extinction training and retrieval. Impaired extinction retrieval in S1 mice was associated with elevated PL single-unit firing, as compared to firing in extinguishing B6 mice, consistent with the hypothesized pro-fear contribution of PL. Analysis of local field potentials also revealed significantly higher gamma power in the PL of Sthan B6 mice during extinction training and retrieval. In the vmPFC, impaired extinction in S1 mice was also associated with exaggerated single-unit firing, relative to B6 mice. This is in apparent contradiction to evidence that IL activity promotes extinction, but could reflect a (failed) compensatory effort by the vmPFC to mitigate fear-promoting activity in other regions, such as the PL or amygdala. In support of this hypothesis, augmenting IL activity via direct infusion of the GABAA receptor antagonist picrotoxin rescued impaired extinction retrieval in S1 mice. Chronic fluoxetine treatment produced modest reductions in fear during extinction retrieval and increased the number of Zif268-labeled cells in layer II of IL, but failed to increase vmPFC single-unit firing. Collectively, these findings further support the important contribution these cortical regions play in determining the balance between robust extinction on the one hand, and sustained fear on the other. Elucidating the precise nature of these roles could help inform understanding of the pathophysiology of fear-related anxiety disorders. PMID:24231425

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowland, Clare E.; Fedin, Igor; Diroll, Benjamin T.

Elevated temperature optoelectronic performance of semiconductor nanomaterials remains an important issue for applications. Here we examine two-dimensional CdSe nanoplatelets (NPs) and CdS/CdSe/CdS shell/core/shell sandwich NPs at temperatures ranging from 300-700 K using static and transient spectroscopies as well as in-situ transmission electron microscopy. NPs exhibit reversible changes in PL intensity, spectral position, and emission linewidth with temperature elevation up to ~500 K, losing a factor of ~8 to 10 in PL intensity at 400 K relative to ambient. Temperature elevation above ~500 K yields thickness dependent, irreversible degradation in optical properties. Electron microscopy relates stability of the NP morphology upmore » to near 600 K followed by sintering and evaporation at still higher temperatures. The mechanism of reversible PL loss, based on differences in decay dynamics between time-resolved photoluminescence and transient absorption, arise primarily from hole trapping in both NPs and sandwich NPs.« less

Spin-exciton interaction and related micro-photoluminescence spectra of ZnSe:Mn DMS nanoribbon

NASA Astrophysics Data System (ADS)

Hou, Lipeng; Zhou, Weichang; Zou, Bingsuo; Zhang, Yu; Han, Junbo; Yang, Xinxin; Gong, Zhihong; Li, Jingbo; Xie, Sishen; Shi, Li-Jie

2017-03-01

For their spintronic applications the magnetic and optical properties of diluted magnetic semiconductors (DMS) have been studied widely. However, the exact relationships between the magnetic interactions and optical emission behaviors in DMS are not well understood yet due to their complicated microstructural and compositional characters from different growth and preparation techniques. Manganese (Mn) doped ZnSe nanoribbons with high quality were obtained by using the chemical vapor deposition (CVD) method. Successful Mn ion doping in a single ZnSe nanoribbon was identified by elemental energy-dispersive x-ray spectroscopy mapping and micro-photoluminescence (PL) mapping of intrinsic d-d optical transition at 580 nm, i.e. the transition of 4 T 1(4 G) → 6 A 1(6 s),. Besides the d-d transition PL peak at 580 nm, two other PL peaks related to Mn ion aggregates in the ZnSe lattice were detected at 664 nm and 530 nm, which were assigned to the d-d transitions from the Mn2+-Mn2+ pairs with ferromagnetic (FM) coupling and antiferromagnetic (AFM) coupling, respectively. Moreover, AFM pair formation goes along with strong coupling with acoustic phonon or structural defects. These arguments were supported by temperature-dependent PL spectra, power-dependent PL lifetimes, and first-principle calculations. Due to the ferromagnetic pair existence, an exciton magnetic polaron (EMP) is formed and emits at 460 nm. Defect existence favors the AFM pair, which also can account for its giant enhancement of spin-orbital coupling and the spin Hall effect observed in PRL 97, 126603(2006) and PRL 96, 196404(2006). These emission results of DMS reflect their relation to local sp-d hybridization, spin-spin magnetic coupling, exciton-spin or phonon interactions covering structural relaxations. This kind of material can be used to study the exciton-spin interaction and may find applications in spin-related photonic devices besides spintronics.

Comparison of orally administered cannabis extract and delta-9-tetrahydrocannabinol in treating patients with cancer-related anorexia-cachexia syndrome: a multicenter, phase III, randomized, double-blind, placebo-controlled clinical trial from the Cannabis-In-Cachexia-Study-Group.

PubMed

Strasser, Florian; Luftner, Diana; Possinger, Kurt; Ernst, Gernot; Ruhstaller, Thomas; Meissner, Winfried; Ko, You-Dschun; Schnelle, Martin; Reif, Marcus; Cerny, Thomas

2006-07-20

To compare the effects of cannabis extract (CE), delta-9-tetrahydrocannabinol (THC), and placebo (PL) on appetite and quality of life (QOL) in patients with cancer-related anorexia-cachexia syndrome (CACS). Adult patients with advanced cancer, CACS, weight loss (> or = 5% over 6 months), and Eastern Cooperative Oncology Group (ECOG) performance status (PS) < or = 2 were randomly assigned (2:2:1) to receive CE (standardized for 2.5 mg THC and 1 mg cannabidiol) or THC (2.5 mg) or PL orally, twice daily for 6 weeks. Appetite, mood, and nausea were monitored daily with a visual analog scale (VAS); QOL was assessed with the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 (composite score: questions 29 and 30). Cannabinoid-related toxicity was assessed every 2 weeks. Of 289 patients screened, 243 were randomly assigned and 164 (CE, 66 of 95 patients; THC, 65 of 100 patients; and PL, 33 of 48 patients) completed treatment. At baseline, groups were comparable for age (mean, 61 years), sex (54% men), weight loss (32% > or = 10%), PS (13% ECOG = 2), antineoplastic treatment (50%), appetite (mean VAS score, 31/100 mm), and QOL (mean score, 30/100). Intent-to-treat analysis showed no significant differences between the three arms for appetite, QOL, or cannabinoid-related toxicity. Increased appetite was reported by 73%, 58%, and 69% of patients receiving CE, THC, or PL, respectively. An independent data review board recommended termination of recruitment because of insufficient differences between study arms. CE at the oral dose administered was well tolerated by these patients with CACS. No differences in patients' appetite or QOL were found either between CE, THC, and PL or between CE and THC at the dosages investigated.

Transcriptome sequencing of a chimaera reveals coordinated expression of anthocyanin biosynthetic genes mediating yellow formation in herbaceous peony (Paeonia lactiflora Pall.).

PubMed

Zhao, Daqiu; Jiang, Yao; Ning, Chuanlong; Meng, Jiasong; Lin, Shasha; Ding, Wen; Tao, Jun

2014-08-19

Herbaceous peony (Paeonia lactiflora Pall.) is a traditional flower in China and a wedding attractive flower in worldwide. In its flower colour, yellow is the rarest which is ten times the price of the other colours. However, the breeding of new yellow P. lactiflora varieties using genetic engineering is severely limited due to the little-known biochemical and molecular mechanisms underlying its characteristic formation. In this study, two cDNA libraries generated from P. lactiflora chimaera with red outer-petal and yellow inner-petal were sequenced using an Illumina HiSeq™ 2000 platform. 66,179,398 and 65,481,444 total raw reads from red outer-petal and yellow inner-petal cDNA libraries were generated, which were assembled into 61,431 and 70,359 Unigenes with an average length of 628 and 617 nt, respectively. Moreover, 61,408 non-redundant All-unigenes were obtained, with 37,511 All-unigenes (61.08%) annotated in public databases. In addition, 6,345 All-unigenes were differentially expressed between the red outer-petal and yellow inner-petal, with 3,899 up-regulated and 2,446 down-regulated All-unigenes, and the flavonoid metabolic pathway related to colour development was identified using the Kyoto encyclopedia of genes and genomes database (KEGG). Subsequently, the expression patterns of 10 candidate differentially expressed genes (DEGs) involved in the flavonoid metabolic pathway were examined, and flavonoids were qualitatively and quantitatively analysed. Numerous anthoxanthins (flavone and flavonol) and a few anthocyanins were detected in the yellow inner-petal, which were all lower than those in the red outer-petal due to the low expression levels of the phenylalanine ammonialyase gene (PlPAL), flavonol synthase gene (PlFLS), dihydroflavonol 4-reductase gene (PlDFR), anthocyanidin synthase gene (PlANS), anthocyanidin 3-O-glucosyltransferase gene (Pl3GT) and anthocyanidin 5-O-glucosyltransferase gene (Pl5GT). Transcriptome sequencing (RNA-Seq) analysis based on the high throughput sequencing technology was an efficient approach to identify critical genes in P. lactiflora and other non-model plants. The flavonoid metabolic pathway and glucide metabolic pathway were identified as relatived yellow formation in P. lactiflora, PlPAL, PlFLS, PlDFR, PlANS, Pl3GT and Pl5GT were selected as potential candidates involved in flavonoid metabolic pathway, which inducing inhibition of anthocyanin biosynthesis mediated yellow formation in P. lactiflora. This study could lay a theoretical foundation for breeding new yellow P. lactiflora varieties.

Steady state and time resolved optical characterization studies of Zn 2SnO 4 nanowires for solar cell applications

DOE PAGES

Yakami, Baichhabi R.; Poudyal, Uma; Nandyala, Shashank R.; ...

2016-10-25

Nanowires are a promising option for sensitized solar cells, sensors, and display technology. Most of the work thus far has focused on binary oxides for these nanowires, but ternary oxides have advantages in additional control of optical and electronic properties. Here, we report on the diffuse reflectance, Low Temperature and Room Temperature Photoluminescence (PL), PL excitation spectrum, and Time Resolved PL (TRPL) of Zinc Tin Oxide (ZTO) nanowires grown by Chemical Vapor Deposition. The PL from the ZTO nanowires does not exhibit any band gap or near gap emission, and the diffuse reflectance measurement confirms that these ZTO nanowires havemore » a direct forbidden transition. The broad PL spectrum reveals two Gaussian peaks centered at 1.86 eV (red) and 2.81 eV (blue), representing two distinct defect states or complexes. The PL spectra were further studied by the Time Resolved Emission Spectrum and intensity dependent PL and TRPL. The time resolved measurements show complex non-exponential decays at all wavelengths, indicative of defect to defect transitions, and the red emissive states decay much slower than the blue emissive states. The effects of annealing in air and vacuum are studied to investigate the origin of the defect states in the nanowires, showing that the blue states are related to oxygen vacancies. We propose an energy band model for the nanowires containing defect states within the band gap and the associated transitions between these states that are consistent with our measurements.« less

Norepinephrine in prelimbic cortex delays extinction of amphetamine-induced conditioned place preference.

PubMed

Latagliata, Emanuele Claudio; Saccoccio, Pamela; Milia, Chiara; Puglisi-Allegra, Stefano

2016-03-01

Drug-associated cues exposure to induce extinction is a useful strategy to contrast cue-induced drug seeking. Treatments aimed at reducing motivational properties of cues are considered highly promising since they could decrease their ability to induce drug-conditioned behaviors. Norepinephrine (NE) in the medial prefrontal cortex (mPFC) is critical for attribution of motivational salience to highly salient stimuli, suggesting a major role in prelimbic (PL) mpFC to modulate the motivational properties of drug-related cues, invigorating them, and consequently, delaying extinction. To investigate if NE in PL fosters the maintenance of drug-seeking behavior, we assessed its role on amphetamine-induced conditioned place preference (CPP). Moreover, to affirm the specificity of NE in PL, we also assessed the role of NE in the infralimbic (IL) mPFC. The effects of selective NE depletion in the PL or in the IL of C57BL/6J mice were assessed on the expression of amphetamine-induced CPP before and after extinction procedure. NE-depleted mice in PL extinguished preference for Amph-paired chamber long before sham animals. By contrast, IL-depleted animals maintained place preference for more than 4 weeks after the procedure of extinction, having at that moment interrupted the test. Inactivation of NE in PL cortex blunts amphetamine-induced CPP, thus fostering extinction and showing to be critical for the maintenance of conditioned Amph-seeking behavior. Opposite effects of NE depletion in IL, seemingly in agreement with literature on extinction, are discussed in terms of balance of activity between PL and IL in extinction.

Photoluminescent enhancement of CdSe/Cd(1-x) Zn(x)S quantum dots by hexadecylamine at room temperature.

PubMed

Yang, Jie; Yang, Ping

2012-09-01

CdSe/Cd(1-x) Zn(x)S core/shell quantum dots (QDs) were fabricated in 1-octadecene via a two step synthesis. CdSe cores were first prepared using CdO, trioctylphosphine (TOP) selenium, and stearic acid. Subsquently, a Cd(1-x) Zn(x)S shell coating was carried out using zinc acetate dihydrate, cadmium acetate dihydrate, TOPS, and hexadecylamine (HDA) starting materials in the friendly organic system under relatively low temperature. The absorption and photoluminescence (PL) spectra have a significant red shift after the coverage of Cd(1-x)Zn(x)S shell on CdSe cores. The X-ray diffraction analysis of samples confirmed the formation of core/shell structure. The PL quantum yields (QYs) of CdSe/Cd(1-x)Zn(x)S QDs were improved gradually with time at room temperature. This is ascribed to the surface passivation of HDA to the QDs during store. This phenomenon was confirmed by the Fourier transform infrared spectrum of samples. Namely, HDA does not capped on the surface of as-prepared QDs, in which a low PL QYs was observed (less than 10%). Being storing for certain time, HDA attached to the surface of the QDs, in which the PL QYs increased (up to 31%) and the full width at half maximum of PL spectra decreased. Moreover, the fluorescence decay curve of the core/shell QDs is closer to a biexponential decay profile and has a longer average PL lifetime. The variation of average PL lifetime also indicated the influence of HDA during store.

Steady state and time resolved optical characterization studies of Zn 2SnO 4 nanowires for solar cell applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yakami, Baichhabi R.; Poudyal, Uma; Nandyala, Shashank R.

Nanowires are a promising option for sensitized solar cells, sensors, and display technology. Most of the work thus far has focused on binary oxides for these nanowires, but ternary oxides have advantages in additional control of optical and electronic properties. Here, we report on the diffuse reflectance, Low Temperature and Room Temperature Photoluminescence (PL), PL excitation spectrum, and Time Resolved PL (TRPL) of Zinc Tin Oxide (ZTO) nanowires grown by Chemical Vapor Deposition. The PL from the ZTO nanowires does not exhibit any band gap or near gap emission, and the diffuse reflectance measurement confirms that these ZTO nanowires havemore » a direct forbidden transition. The broad PL spectrum reveals two Gaussian peaks centered at 1.86 eV (red) and 2.81 eV (blue), representing two distinct defect states or complexes. The PL spectra were further studied by the Time Resolved Emission Spectrum and intensity dependent PL and TRPL. The time resolved measurements show complex non-exponential decays at all wavelengths, indicative of defect to defect transitions, and the red emissive states decay much slower than the blue emissive states. The effects of annealing in air and vacuum are studied to investigate the origin of the defect states in the nanowires, showing that the blue states are related to oxygen vacancies. We propose an energy band model for the nanowires containing defect states within the band gap and the associated transitions between these states that are consistent with our measurements.« less

SMC west halo: a slice of the galaxy that is being tidally stripped?. Star clusters trace age and metallicity gradients

NASA Astrophysics Data System (ADS)

Dias, B.; Kerber, L.; Barbuy, B.; Bica, E.; Ortolani, S.

2016-06-01

Context. The evolution and structure of the Magellanic Clouds is currently under debate. The classical scenario in which both the Large and Small Magellanic Clouds (LMC, SMC) are orbiting the Milky Way has been challenged by an alternative in which the LMC and SMC are in their first close passage to our Galaxy. The clouds are close enough to us to allow spatially resolved observation of their stars, and detailed studies of stellar populations in the galaxies are expected to be able to constrain the proposed scenarios. In particular, the west halo (WH) of the SMC was recently characterized with radial trends in age and metallicity that indicate tidal disruption. Aims: We intend to increase the sample of star clusters in the west halo of the SMC with homogeneous age, metallicity, and distance derivations to allow a better determination of age and metallicity gradients in this region. Positions are compared with the orbital plane of the SMC from models. Methods: Comparisons of observed and synthetic V(B-V) colour-magnitude diagrams were used to derive age, metallicity, distance, and reddening for star clusters in the SMC west halo. Observations were carried out using the 4.1 m SOAR telescope. Photometric completeness was determined through artificial star tests, and the members were selected by statistical comparison with a control field. Results: We derived an age of 1.23 ± 0.07 Gyr and [Fe/H] = -0.87 ± 0.07 for the reference cluster NGC 152, compatible with literature parameters. Age and metallicity gradients are confirmed in the WH: 2.6 ± 0.6 Gyr/° and -0.19 ± 0.09 dex/°, respectively. The age-metallicity relation for the WH has a low dispersion in metallicity and is compatible with a burst model of chemical enrichment. All WH clusters seem to follow the same stellar distribution predicted by dynamical models, with the exception of AM-3, which should belong to the counter-bridge. Brück 6 is the youngest cluster in our sample. It is only 130 ± 40 Myr old and may have been formed during the tidal interaction of SMC-LMC that created the WH and the Magellanic bridge. Conclusions: We suggest that it is crucial to split the SMC cluster population into groups: main body, wing and bridge, counter-bridge, and WH. This is the way to analyse the complex star formation and dynamical history of our neighbour. In particular, we show that the WH has clear age and metallicity gradients and an age-metallicity relation that is also compatible with the dynamical model that claims a tidal influence of the LMC on the SMC. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).Tables of photometry are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A11

Fernblock (Polypodium leucotomos Extract): Molecular Mechanisms and Pleiotropic Effects in Light-Related Skin Conditions, Photoaging and Skin Cancers, a Review

PubMed Central

Parrado, Concepcion; Mascaraque, Marta; Gilaberte, Yolanda; Juarranz, Angeles; Gonzalez, Salvador

2016-01-01

Healthier life styles include increased outdoors time practicing sports and walking. This means increased exposure to the sun, leading to higher risk of sunburn, photoaging and skin cancer. In addition to topical barrier products, oral supplementations of various botanicals endowed with antioxidant activity are emerging as novel method of photoprotection. Polypodium leucotomos extract (PL, commercial name Fernblock®, IFC Group, Spain) is a powerful antioxidant due to its high content of phenolic compounds. PL is administered orally, with proven safety, and it can also be used topically. Its mechanisms include inhibition of the generation and release of reactive oxygen species (ROS) by ultraviolet (UV) light. It also prevents UV- and ROS-induced DNA damage with inhibition of AP1 and NF-κB and protection of natural antioxidant enzyme systems. At the cellular level, PL decreases cellular apoptosis and necrosis mediated UV and inhibits abnormal extracellular matrix remodeling. PL reduces inflammation, prevents immunosuppression, activates tumor suppressor p53 and inhibits UV-induced cyclooxygenase-2 (COX-2) enzyme expression. In agreement with increased p53 activity, PL decreased UV radiation-induced cell proliferation. PL also prevents common deletions mitochondrial DNA damage induced by UVA, and MMP-1 expression induced Visible Light and Infrared Radiation. These cellular and molecular effects are reflected in inhibitions of carcinogenesis and photoaging. PMID:27367679

Fernblock (Polypodium leucotomos Extract): Molecular Mechanisms and Pleiotropic Effects in Light-Related Skin Conditions, Photoaging and Skin Cancers, a Review.

PubMed

Parrado, Concepcion; Mascaraque, Marta; Gilaberte, Yolanda; Juarranz, Angeles; Gonzalez, Salvador

2016-06-29

Healthier life styles include increased outdoors time practicing sports and walking. This means increased exposure to the sun, leading to higher risk of sunburn, photoaging and skin cancer. In addition to topical barrier products, oral supplementations of various botanicals endowed with antioxidant activity are emerging as novel method of photoprotection. Polypodium leucotomos extract (PL, commercial name Fernblock(®), IFC Group, Spain) is a powerful antioxidant due to its high content of phenolic compounds. PL is administered orally, with proven safety, and it can also be used topically. Its mechanisms include inhibition of the generation and release of reactive oxygen species (ROS) by ultraviolet (UV) light. It also prevents UV- and ROS-induced DNA damage with inhibition of AP1 and NF-κB and protection of natural antioxidant enzyme systems. At the cellular level, PL decreases cellular apoptosis and necrosis mediated UV and inhibits abnormal extracellular matrix remodeling. PL reduces inflammation, prevents immunosuppression, activates tumor suppressor p53 and inhibits UV-induced cyclooxygenase-2 (COX-2) enzyme expression. In agreement with increased p53 activity, PL decreased UV radiation-induced cell proliferation. PL also prevents common deletions mitochondrial DNA damage induced by UVA, and MMP-1 expression induced Visible Light and Infrared Radiation. These cellular and molecular effects are reflected in inhibitions of carcinogenesis and photoaging.

Real-Time Observation of Iodide Ion Migration in Methylammonium Lead Halide Perovskites.

PubMed

Li, Cheng; Guerrero, Antonio; Zhong, Yu; Gräser, Anna; Luna, Carlos Andres Melo; Köhler, Jürgen; Bisquert, Juan; Hildner, Richard; Huettner, Sven

2017-11-01

Organic-inorganic metal halide perovskites (e.g., CH 3 NH 3 PbI 3- x Cl x ) emerge as a promising optoelectronic material. However, the Shockley-Queisser limit for the power conversion efficiency (PCE) of perovskite-based photovoltaic devices is still not reached. Nonradiative recombination pathways may play a significant role and appear as photoluminescence (PL) inactive (or dark) areas on perovskite films. Although these observations are related to the presence of ions/defects, the underlying fundamental physics and detailed microscopic processes, concerning trap/defect status, ion migration, etc., still remain poorly understood. Here correlated wide-field PL microscopy and impedance spectroscopy are utilized on perovskite films to in situ investigate both the spatial and the temporal evolution of these PL inactive areas under external electric fields. The formation of PL inactive domains is attributed to the migration and accumulation of iodide ions under external fields. Hence, we are able to characterize the kinetic processes and determine the drift velocities of these ions. In addition, it is shown that I 2 vapor directly affects the PL quenching of a perovskite film, which provides evidence that the migration/segregation of iodide ions plays an important role in the PL quenching and consequently limits the PCE of organometal halide-based perovskite photovoltaic devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plumbagin, a vitamin K3 analogue ameliorate malaria pathogenesis by inhibiting oxidative stress and inflammation.

PubMed

Gupta, Amit Chand; Mohanty, Shilpa; Saxena, Archana; Maurya, Anil Kumar; Bawankule, Dnyaneshwar U

2018-03-22

Plumbagin, a vitamin K3 analogue is the major active constituent in several plants including root of Plumbago indica Linn. This compound has been shown to exhibit a wide spectrum of pharmacological activities. The present investigation was to evaluate the ameliorative effects of plumbagin (PL) against severe malaria pathogenesis due to involvement of oxidative stress and inflammatory response in Plasmodium berghei infected malaria in mice. Malaria pathogenesis was induced by intra-peritoneal injection of P. berghei infected red blood cells into the Swiss albino mice. PL was administered orally at doses of 3, 10 and 30 mg/kg/day following Peter's 4 day suppression test. Oral administration of PL showed significant reduction of parasitaemia and increase in mean survival time. PL treatment is also attributed to significant increase in the blood glucose and haemoglobin level when compared with vehicle-treated infected mice. Significant inhibition in level of oxidative stress and pro-inflammation related markers were observed in PL treated group. The trend of inhibition in oxidative stress markers level after oral treatment of PL was MPO > LPO > ROS in organ injury in P. berghei infected mice. This study showed that plumbagin is able to ameliorate malaria pathogenesis by augmenting anti-oxidative and anti-inflammatory mechanism apart from its effect on reducing parasitaemia and increasing mean survival time of malaria-induced mice.

Epidermal growth factor stimulates mouse placental lactogen I but inhibits mouse placental lactogen II secretion in vitro.

PubMed Central

Yamaguchi, M; Ogren, L; Endo, H; Thordarson, G; Kensinger, R; Talamantes, F

1992-01-01

This study was undertaken to determine whether epidermal growth factor (EGF) regulates the secretion of mouse placental lactogen (mPL)-I and mPL-II. Primary cell cultures were prepared from placentas from days 7, 9, and 11 of pregnancy and cultured for up to 5 days. Addition of EGF (20 ng/ml) to the medium resulted in significant stimulation of mPL-I secretion by the second day of culture in cells from days 7 and 9 of pregnancy and significant inhibition of mPL-II secretion by the third or fourth day of culture in cells from days 7, 9, and 11. Dose-response studies carried out with cells from day 7 of pregnancy demonstrated that the minimum concentration of EGF that stimulated mPL-I secretion and inhibited mPL-II secretion was 1.0 ng/ml. EGF did not affect the DNA content of the cells or cell viability, assessed by trypan blue exclusion, nor did it have a general effect on protein synthesis. There are three types of PL-containing giant cells in mouse placental cell cultures: cells that contain either mPL-I or mPL-II and cells that contain both hormones. Immunocytochemical analysis and the reverse hemolytic plaque assay indicated that EGF treatment was accompanied by a significant increase in the number of cells that produce mPL-I, but among the PL cells that contained mPL-I, there was no change in the fraction of cells that contained only mPL-I or the fraction that contained both mPL-I and mPL-II. In contrast, EGF treatment did affect the distribution of mPL-II among PL cells. In control cultures, about 75% of the cells that contained mPL-II also contained mPL-I, but in EGF-treated cultures, all of the cells that contained mPL-II also contained mPL-I. These data suggest that EGF regulates mPL-I and mPL-II secretion at least partly by regulating PL cell differentiation. PMID:1454826

Nano-engineered polyurethane resin-modified concrete.

DOT National Transportation Integrated Search

2014-04-01

The goal of the proposed work is to investigate the application of nano-engineered polyurethane (NEPU) emulsions for latex modified : concrete (LMC). NEPU emulsions are non-toxic, environment friendly, durable over a wide temperature range, provide b...

Choriodecidual Cells from Term Human Pregnancies Show Distinctive Functional Properties Related to the Induction of Labor

PubMed Central

Castillo-Castrejon, Marisol; Meraz-Cruz, Noemí; Gomez-Lopez, Nardhy; Flores-Pliego, Arturo; Beltrán-Montoya, Jorge; Viveros-Alcaráz, Martín; Vadillo-Ortega, Felipe

2014-01-01

Problem Human parturition is associated with an intrauterine pro-inflammatory environment in the choriodecidua. Evidence that some mediators of this signaling cascade also elicit responses leading to labor prompted us to characterize the cellular sources of these mediators in the human choriodecidua. Method of study Leukocyte-enriched preparations from human choriodecidua (ChL) and intervillous placental blood leukocytes (PL) were maintained in culture. Secretions of inflammatory cytokines, chemokines and MMP-9 were documented. Leukocyte phenotype of ChL and PL was determined by flow cytometry using specific fluorochrome-conjugated antibodies. Results and Conclusions ChL showed a distinct pro-inflammatory secretion pattern of cytokines and chemokines when compared with PL, including higher amounts of TNF-α and IL-6, and decreased secretions of IL-4 and IL-1ra. ChL also secreted more MIP-1α and MCP-1 and MMP-9 than PL. No significant differences were found in leukocytes subsets between compartments. Based on our findings, we propose that ChL isolated from fetal membranes at term are functionally different from PL and may collaborate to modulate the microenvironment linked to induction and progression of human labor. PMID:24286217

Shell Thickness Dependence of Interparticle Energy Transfer in Core-Shell ZnSe/ZnSe Quantum Dots Doping with Europium

NASA Astrophysics Data System (ADS)

Liu, Ni; Li, Shuxin; Wang, Caifeng; Li, Jie

2018-04-01

Low-toxic core-shell ZnSe:Eu/ZnS quantum dots (QDs) were prepared through two steps in water solution: nucleation doping and epitaxial shell grown. The structural and morphological characteristics of ZnSe/ZnS:Eu QDs with different shell thickness were explored by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results. The characteristic photoluminescence (PL) intensity of Eu ions was enhanced whereas that of band-edge luminescence and defect-related luminescence of ZnSe QDs was decreased with increasing shell thickness. The transformation of PL intensity revealed an efficient energy transfer process between ZnSe and Eu. The PL intensity ratio of Eu ions ( I 613) to ZnSe QDs ( I B ) under different shell thickness was systemically analyzed by PL spectra and time-resolved PL spectra. The obtained results were in agreement with the theory analysis results by the kinetic theory of energy transfer, revealing that energy was transmitted in the form of dipole-electric dipole interaction. This particular method of adjusting luminous via changing the shell thickness can provide valuable insights towards the fundamental understanding and application of QDs in the field of optoelectronics.

Kinetic energy dependence of carrier diffusion in a GaAs epilayer studied by wavelength selective PL imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, S.; Su, L. Q.; Kon, J.

Photoluminescence (PL) imaging has been shown to be an efficient technique for investigating carrier diffusion in semiconductors. In the past, the measurement was typically carried out by measuring at one wavelength (e.g., at the band gap) or simply the whole emission band. At room temperature in a semiconductor like GaAs, the band-to-band PL emission may occur in a spectral range over 200 meV, vastly exceeding the average thermal energy of about 26 meV. To investigate the potential dependence of the carrier diffusion on the carrier kinetic energy, we performed wavelength selective PL imaging on a GaAs double hetero-structure in amore » spectral range from about 70 meV above to 50 meV below the bandgap, extracting the carrier diffusion lengths at different PL wavelengths by fitting the imaging data to a theoretical model. The results clearly show that the locally generated carriers of different kinetic energies mostly diffuse together, maintaining the same thermal distribution throughout the diffusion process. Potential effects related to carrier density, self-absorption, lateral wave-guiding, and local heating are also discussed.« less

Near-IR period-luminosity relations for pulsating stars in ω Centauri (NGC 5139)

NASA Astrophysics Data System (ADS)

Navarrete, C.; Catelan, M.; Contreras Ramos, R.; Alonso-García, J.; Gran, F.; Dékány, I.; Minniti, D.

2017-08-01

Aims: The globular cluster ω Centauri (NGC 5139) hosts hundreds of pulsating variable stars of different types, thus representing a treasure trove for studies of their corresponding period-luminosity (PL) relations. Our goal in this study is to obtain the PL relations for RR Lyrae and SX Phoenicis stars in the field of the cluster, based on high-quality, well-sampled light curves in the near-infrared (IR). Methods: Observations were carried out using the VISTA InfraRed CAMera (VIRCAM) mounted on the Visible and Infrared Survey Telescope for Astronomy (VISTA). A total of 42 epochs in J and 100 epochs in KS were obtained, spanning 352 days. Point-spread function photometry was performed using DoPhot and DAOPHOT crowded-field photometry packages in the outer and inner regions of the cluster, respectively. Results: Based on the comprehensive catalog of near-IR light curves thus secured, PL relations were obtained for the different types of pulsators in the cluster, both in the J and KS bands. This includes the first PL relations in the near-IR for fundamental-mode SX Phoenicis stars. The near-IR magnitudes and periods of Type II Cepheids and RR Lyrae stars were used to derive an updated true distance modulus to the cluster, with a resulting value of (m - M)0 = 13.708 ± 0.035 ± 0.10 mag, where the error bars correspond to the adopted statistical and systematic errors, respectively. Adding the errors in quadrature, this is equivalent to a heliocentric distance of 5.52 ± 0.27 kpc. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, with the VISTA telescope (project ID 087.D-0472, PI R. Angeloni).

Effect of infection with bovine leukosis virus on lymphocyte proliferation and apoptosis in dairy cattle.

PubMed

Erskine, Ronald J; Corl, Christine M; Gandy, Jeffery C; Sordillo, Lorraine M

2011-08-01

To determine effects of infection with bovine leukosis virus (BLV) on lymphocyte proliferation and apoptosis in dairy cattle. 27 adult Holstein cows. Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood from lactating Holstein cows seronegative for BLV (n = 9 cows), seropositive for BLV and aleukemic (aleukemic; 9), and seropositive for BLV and persistently lymphocytotic (PL; 9). Isolated PBMCs were assayed for mitogen-induced proliferation and were analyzed by means of flow cytometry. The PBMCs from a subset of each group were assayed for apoptosis, caspase-9 activity, and expression of selected genes related to apoptosis. PL cows had significantly higher total lymphocyte counts and significantly lower proportions of T-lymphocyte populations than did BLV-negative and aleukemic cows. Both groups of BLV-infected cows had significantly higher proportions of B cells and major histocompatibility complex II-expressing cells than did BLV-negative cows. Proliferation with concanavalin A was significantly lower for PL cows, compared with proliferation for BLV-negative cows. Pokeweed mitogen-induced proliferation was significantly higher for aleukemic and PL cows than for BLV-negative cows. Gene expression of apoptosis-inhibitory proteins BCL2 and BCL2L1 was significantly higher for aleukemic cows and expression of BCL2 was significantly higher for PL cows than for BLV-negative cows. Cattle infected with BLV had marked changes in PBMC populations accompanied by alterations in proliferation and apoptosis mechanisms. Because the relative distribution and function of lymphocyte populations are critical for immune competence, additional studies are needed to investigate the ability of BLV-infected cattle to respond to infectious challenge.

Bacterial Population in Intestines of the Black Tiger Shrimp (Penaeus monodon) under Different Growth Stages

PubMed Central

Rungrassamee, Wanilada; Klanchui, Amornpan; Chaiyapechara, Sage; Maibunkaew, Sawarot; Tangphatsornruang, Sithichoke; Jiravanichpaisal, Pikul; Karoonuthaisiri, Nitsara

2013-01-01

Intestinal bacterial communities in aquaculture have been drawn to attention due to potential benefit to their hosts. To identify core intestinal bacteria in the black tiger shrimp (Penaeus monodon), bacterial populations of disease-free shrimp were characterized from intestines of four developmental stages (15-day-old post larvae (PL15), 1- (J1), 2- (J2), and 3-month-old (J3) juveniles) using pyrosequencing, real-time PCR and denaturing gradient gel electrophoresis (DGGE) approaches. A total of 25,121 pyrosequencing reads (reading length = 442±24 bases) were obtained, which were categorized by barcode for PL15 (7,045 sequences), J1 (3,055 sequences), J2 (13,130 sequences) and J3 (1,890 sequences). Bacteria in the phyla Bacteroides, Firmicutes and Proteobacteria were found in intestines at all four growth stages. There were 88, 14, 27, and 20 bacterial genera associated with the intestinal tract of PL15, J1, J2 and J3, respectively. Pyrosequencing analysis revealed that Proteobacteria (class Gammaproteobacteria) was a dominant bacteria group with a relative abundance of 89% for PL15 and 99% for J1, J2 and J3. Real-time PCR assay also confirmed that Gammaproteobacteria had the highest relative abundance in intestines from all growth stages. Intestinal bacterial communities from the three juvenile stages were more similar to each other than that of the PL shrimp based on PCA analyses of pyrosequencing results and their DGGE profiles. This study provides descriptive bacterial communities associated to the black tiger shrimp intestines during these growth development stages in rearing facilities. PMID:23577162

Bacterial population in intestines of the black tiger shrimp (Penaeus monodon) under different growth stages.

PubMed

Rungrassamee, Wanilada; Klanchui, Amornpan; Chaiyapechara, Sage; Maibunkaew, Sawarot; Tangphatsornruang, Sithichoke; Jiravanichpaisal, Pikul; Karoonuthaisiri, Nitsara

2013-01-01

Intestinal bacterial communities in aquaculture have been drawn to attention due to potential benefit to their hosts. To identify core intestinal bacteria in the black tiger shrimp (Penaeus monodon), bacterial populations of disease-free shrimp were characterized from intestines of four developmental stages (15-day-old post larvae (PL15), 1- (J1), 2- (J2), and 3-month-old (J3) juveniles) using pyrosequencing, real-time PCR and denaturing gradient gel electrophoresis (DGGE) approaches. A total of 25,121 pyrosequencing reads (reading length = 442±24 bases) were obtained, which were categorized by barcode for PL15 (7,045 sequences), J1 (3,055 sequences), J2 (13,130 sequences) and J3 (1,890 sequences). Bacteria in the phyla Bacteroides, Firmicutes and Proteobacteria were found in intestines at all four growth stages. There were 88, 14, 27, and 20 bacterial genera associated with the intestinal tract of PL15, J1, J2 and J3, respectively. Pyrosequencing analysis revealed that Proteobacteria (class Gammaproteobacteria) was a dominant bacteria group with a relative abundance of 89% for PL15 and 99% for J1, J2 and J3. Real-time PCR assay also confirmed that Gammaproteobacteria had the highest relative abundance in intestines from all growth stages. Intestinal bacterial communities from the three juvenile stages were more similar to each other than that of the PL shrimp based on PCA analyses of pyrosequencing results and their DGGE profiles. This study provides descriptive bacterial communities associated to the black tiger shrimp intestines during these growth development stages in rearing facilities.

Photoluminescence emission spectra of Makrofol® DE 1-1 upon irradiation with ultraviolet radiation

NASA Astrophysics Data System (ADS)

El Ghazaly, M.; Aydarous, Abdulkadir

Photoluminescence (PL) emission spectra of Makrofol® DE 1-1 (bisphenol-A based polycarbonate) upon irradiation with ultraviolet radiation of different wavelengths were investigated. The absorption-and attenuation coefficient measurements revealed that the Makrofol® DE 1-1 is characterized by high absorbance in the energy range 6.53-4.43 eV but for a lower energy than 4.43 eV, it is approximately transparent. Makrofol® DE 1-1 samples were irradiated with ultraviolet radiation of wavelength in the range from 250 (4.28 eV) to 400 (3.10 eV) nm in step of 10 nm and the corresponding photoluminescence (PL) emission spectra were measured with a spectrofluorometer. It is found that the integrated counts and the peak height of the photoluminescence emission (PL) bands are strongly correlated with the ultraviolet radiation wavelength. They are increased at the ultraviolet radiation wavelength 280 nm and have maximum at 290 nm, thereafter they decrease and diminish at 360 nm of ultraviolet wavelength. The position of the PL emission band peak was red shifted starting from 300 nm, which increased with the increase the ultraviolet radiation wavelength. The PL bandwidth increases linearly with the increase of the ultraviolet radiation wavelength. When Makrofol® DE 1-1 is irradiated with ultraviolet radiation of short wavelength (UVC), the photoluminescence emission spectra peaks also occur in the UVC but of a relatively longer wavelength. The current new findings should be considered carefully when using Makrofol® DE 1-1 in medical applications related to ultraviolet radiation.

Very-Early-Strength Latex-Modified Concrete Overlays

DOT National Transportation Integrated Search

1998-12-01

This report describes the installation and condition of the first two very-early-strength latex-modified concrete (LMC-VE) overlays to be constructed for the Virginia Department of Transportation. The overlays were prepared with a special blended cem...

Very-early-strength latex-modified concrete overlay.

DOT National Transportation Integrated Search

1998-12-01

This paper describes the installation and condition of the first two very-early-strength latex modified concrete (LMC-VE) overlays constructed for the Virginia Department of Transportation. The overlays were prepared with a special blended cement rat...

Energetics and Birth Rates of Supernova Remnants in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Leahy, D. A.

2017-03-01

Published X-ray emission properties for a sample of 50 supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) are used as input for SNR evolution modeling calculations. The forward shock emission is modeled to obtain the initial explosion energy, age, and circumstellar medium density for each SNR in the sample. The resulting age distribution yields a SNR birthrate of 1/(500 yr) for the LMC. The explosion energy distribution is well fit by a log-normal distribution, with a most-probable explosion energy of 0.5× {10}51 erg, with a 1σ dispersion by a factor of 3 in energy. The circumstellar medium density distribution is broader than the explosion energy distribution, with a most-probable density of ˜0.1 cm-3. The shape of the density distribution can be fit with a log-normal distribution, with incompleteness at high density caused by the shorter evolution times of SNRs.

Local normal galaxies

NASA Technical Reports Server (NTRS)

Fichtel, Carl E.

1990-01-01

In the near future, high energy (E greater than 20 MeV) gamma ray astronomy offers the promise of a new means of examining the closest galaxies. Two and possibly three local galaxies, the Small and Large Magellanic Clouds and M31, should be visible to the high energy gamma ray telescope on the Gamma Ray Observatory, and the first should be seen by GAMMA-1. With the assumptions of adequate cosmic ray production and reasonable magnetic field strengths, both of which should likely be satisfied, specific predictions of the gamma ray emission can be made separating the concepts of the galactic and universal nature of cosmic rays. A study of the synchrotron radiation from the Large Magellanic Cloud (LMC) suggests that the cosmic ray density is similar to that in the local region of our galaxy, but not uniform. It is hoped the measurements will be able to verify this independent of assumptions about the magnetic fields in the LMC.

Photoionisation modelling of Nova LMC 1990 #1

NASA Technical Reports Server (NTRS)

Dopita, M. A.; Meatheringham, S. J.; Sutherland, R.; Williams, R. E.; Starrfield, S.; Sonneborn, G.; Shore, S.

1992-01-01

Nova LMC 1990A was a very fast Ne-O-Mg nova, for which a particularly dense coverage of spectral observation in both the UV and optical was obtained. The data for the nebular phase were subjected to an analysis by the photoionization modeling code MAPPINGS 2. The following parameters were obtained: L(sub max) = 8 x 10(exp 4) solar luminosity, T(sub eff) = 2 x 10(exp 5) K and the mass of ejecta = 5/5 x 10(exp -5) solar mass. The abundnace ratios in the ejecta were similar to those obtained by Williams et al. (1985) in the case of V693 CrA 1981. The N/O ratio and the overabundance of Al is consistent with ourburst on a ONeMg white dwarf of mass approximately equal to 1.2 solar mass, but the super-Eddington luminosity, and amount of mass ejected presents some problems to theory.

On fast X-ray rotators with long-term periodicities

NASA Technical Reports Server (NTRS)

Naranan, S.; Elsner, R. F.; Darbro, W.; Ramsey, B. D.; Leahy, D. A.; Weisskopf, M. C.; Williams, A. C.; Hardee, P. E.; Sutherland, P. G.; Grindlay, J. E.

1985-01-01

The support of previous SAS 3 spacecraft observations by new data gathered by the Monitor Proportional Counter aboard the HEAO 2 spacecraft indicates that the pulse period history of the 13.5 sec-pulsing X-ray source LMC X-4 is consistent with standard accretion and torque models only if LMC X-4 is a fast rotator for which the accretion torques nearly cancel. This result leads to a neutron star magnetic field strength estimate of about 1.2 x 10 to the 13th G. Strong evidence is noted for Her X-1's status as a fast rotator, while SMC X-1 is probably an intermediate-to-fast rotator. In the context of slaved disk models for these objects, it is noted that the precession periods expected for the companion stars are significantly longer than the observed 1-2 month time scales; slaved disk models are thereby undermined.

NGC 1866: First Spectroscopic Detection of Fast-rotating Stars in a Young LMC Cluster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dupree, A. K.; Dotter, A.; Johnson, C. I.

High-resolution spectroscopic observations were taken of 29 extended main-sequence turnoff (eMSTO) stars in the young (∼200 Myr) Large Magellanic Cloud (LMC) cluster, NGC 1866, using the Michigan/ Magellan Fiber System and MSpec spectrograph on the Magellan -Clay 6.5 m telescope. These spectra reveal the first direct detection of rapidly rotating stars whose presence has only been inferred from photometric studies. The eMSTO stars exhibit H α emission (indicative of Be-star decretion disks), others have shallow broad H α absorption (consistent with rotation ≳150 km s{sup −1}), or deep H α core absorption signaling lower rotation velocities (≲150 km s{sup −1}).more » The spectra appear consistent with two populations of stars—one rapidly rotating, and the other, younger and slowly rotating.« less

Spectroscopic Results of Gravitational Microlenses: Are These Dark Objects or Faint Stars?

NASA Astrophysics Data System (ADS)

Joseph, C. L.; Gallagher, J.; Phillips, M.

1994-12-01

We report on the spectroscopic results obtained in October 1994 with the 4-meter telescope on Cerro Tololo Interamerican Observatory (CTIO). Spectra of 2 recent microlens candidates toward the Galactic bulge reported by the Optical Gravitational Lens Experiment (OGLE) as well as one caught in the early phases of brightening toward the LMC reported by the MAssive Compact Halo Object (MACHO) Project have been obtained. The spectral coverage is from 6500 to 9800 Angstroms at a resolution of 6 Angstroms. The long-term goal of this spectroscopic study is to obtain censored statistical evidence on the luminosity of the microlenses, constraining the nature of these lenses. Several models of composite spectra of a bulge or LMC star plus a cool lensing star of different spectral types are presented to demonstrate the ranges in the product of luminosity times distance that the faint star could be detected in a composite spectrum.

Enhanced Biodegradability of Pharmaceuticals and Personal Care Products by Ionizing Radiation.

PubMed

Kim, Hyun Young; Lee, O-Mi; Kim, Tae-Hun; Yu, Seungho

2015-04-01

The radiolytic degradation of antibiotic compounds, including lincomycin (LMC), sulfamethoxazole (SMX), and tetracycline (TCN), and the change of biodegradability of the radiation-treated target compounds were evaluated. As a result, the degradation of target antibiotics by hydrolysis, biodegradation, and gamma irradiation showed a compound-dependent manner. However, the biodegradability of all target compounds was enhanced by the gamma irradiation. The enhanced biodegradability after gamma irradiation (2 kGy) followed the trend of LMC (18.89%)

OGLE Collection of Star Clusters. New Objects in the Outskirts of the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Sitek, M.; Szymański, M. K.; Skowron, D. M.; Udalski, A.; Kostrzewa-Rutkowska, Z.; Skowron, J.; Karczmarek, P.; Cieślar, M.; Wyrzykowski, Ł.; Kozłowski, S.; Pietrukowicz, P.; Soszyński, I.; Mróz, P.; Pawlak, M.; Poleski, R.; Ulaczyk, K.

2016-09-01

The Magellanic System (MS), consisting of the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC) and the Magellanic Bridge (MBR), contains diverse sample of star clusters. Their spatial distribution, ages and chemical abundances may provide important information about the history of formation of the whole System. We use deep photometric maps derived from the images collected during the fourth phase of the Optical Gravitational Lensing Experiment (OGLE-IV) to construct the most complete catalog of star clusters in the Large Magellanic Cloud using the homogeneous photometric data. In this paper we present the collection of star clusters found in the area of about 225 square degrees in the outer regions of the LMC. Our sample contains 679 visually identified star cluster candidates, 226 of which were not listed in any of the previously published catalogs. The new clusters are mainly young small open clusters or clusters similar to associations.

Dust Abundance Variations in the Magellanic Clouds: Probing the Life-cycle of Metals with All-sky Surveys

NASA Astrophysics Data System (ADS)

Roman-Duval, Julia; Bot, Caroline; Chastenet, Jeremy; Gordon, Karl

2017-06-01

Observations and modeling suggest that dust abundance (gas-to-dust ratio, G/D) depends on (surface) density. Variations of the G/D provide timescale constraints for the different processes involved in the life cycle of metals in galaxies. Recent G/D measurements based on Herschel data suggest a factor of 5-10 decrease in dust abundance between the dense and diffuse interstellar media (ISM) in the Magellanic Clouds. However, the relative nature of the Herschel measurements precludes definitive conclusions as to the magnitude of those variations. We investigate variations of the dust abundance in the LMC and SMC using all-sky far-infrared surveys, which do not suffer from the limitations of Herschel on their zero-point calibration. We stack the dust spectral energy distribution (SED) at 100, 350, 550, and 850 microns from IRAS and Planck in intervals of gas surface density, model the stacked SEDs to derive the dust surface density, and constrain the relation between G/D and gas surface density in the range 10-100 M ⊙ pc-2 on ˜80 pc scales. We find that G/D decreases by factors of 3 (from 1500 to 500) in the LMC and 7 (from 1.5× {10}4 to 2000) in the SMC between the diffuse and dense ISM. The surface-density-dependence of G/D is consistent with elemental depletions, and with simple modeling of the accretion of gas-phase metals onto dust grains. This result has important implications for the sub-grid modeling of galaxy evolution, and for the calibration of dust-based gas-mass estimates, both locally and at high redshift.

Mineralization by mesenchymal stromal cells is variously modulated depending on commercial platelet lysate preparations.

PubMed

Boraldi, Federica; Burns, Jorge S; Bartolomeo, Angelica; Dominici, Massimo; Quaglino, Daniela

2018-03-01

Numerous cellular models have been developed to investigate calcification for regenerative medicine applications and for the identification of therapeutic targets in various complications associated with age-related diseases. However, results have often been contradictory due to specific culture conditions, cell type ontogeny and aging status. Human platelet lysate (hPL) has been recently investigated as valuable alternative to fetal bovine serum (FBS) in cell culture and bone regeneration. A parallel comparison of how all these multiple factors may converge to influence mineralization has yet to be reported. To compare mineralization of human mesenchymal cell types known to differ in extracellular matrix calcification potency, bone marrow-derived mesenchymal stromal cells and dermal fibroblasts from neonatal and adult donors, at both low and high passages, were investigated in an ex vivo experimental model by supplementing the osteogenic induction medium with FBS or with hPL. Four commercial hPL preparations were profiled by liquid chromatography/electrospray ionization quadrupole time-of-flight spectrometry, and mineralization was visualized by von Kossa staining and quantified by morphometric evaluations after 9, 14 and 21 days of culture. Data demonstrate that (i) commercial hPL preparations differ according to mass spectra profiles, (ii) hPL variously influences mineral deposition depending on cell line and possibly on platelet product preparation methods, (iii) donor age modifies mineral deposition in the presence of the same hPL and (iv) reduced in vitro proliferative capacity affects osteogenic induction and response to hPL. Despite the standardized procedures applied to obtain commercial hPL, this study highlights the divergent effects of different preparations and emphasizes the importance of cellular ontology, donor age and cell proliferative capacity to optimize the osteogenic induction capabilities of mesenchymal stromal cells and design more effective cell-based therapeutic protocols. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Biometrical analysis of the shoulder joint regarding glenoid implant dimensions for arthroplasty.

PubMed

Kircher, Jörn; Bittersohl, Bernd; Zilkens, Christoph; Hedtmann, Achim; Krauspe, Rüdiger

2014-05-01

Reduced bone stock and difficult intraoperative orientation are challenges in glenoid replacement surgery. New implant designs and methods for fixation, such as locking screws, extra-long central pegs and/or central compression screws are targeting these issues. The objective of this study is the analysis of the glenoid dimension regarding maximum central peg diameter and peg length (PL), and maximum screw length (SL) for glenoid fixation. Retrospective analysis of magnetic resonance imaging (n = 50) scans. Measurement of the maximum inferior glenoid diameter (GD), SL, maximum length of a 9.9, 10 and 11.4 mm central peg (PL) in the transverse plane; glenoid version (GV), humeral head diameter (HHD). Two independent measurements. Mean age: 49.0 ± 15.7 years (17-80) (n = 20 female, 49.6 ± 16.0; n = 30 male, 48.6 ± 15.7). Mean values of measurement were GD: 28.9 ± 3.7 mm (21-39); SL: 34.1 ± 4.9 mm (26-44); PL 9.9 mm: 19.4 ± 4.3 mm (9-30); PL 10 mm: 19.0 ± 4.4 mm (8-30); PL 11.4 mm: 16.5 ± 4.1 mm (7-26) with significant gender differences (p = 0.001; p = 0.022; p = 0.001); GV: -0.6° ± 4.9° (-10 to 11); HHD: 50.0 mm ± 4.9 (41-61). There was good correlation between PL and SL (r = 0.32, p = 0.024) and for GD and PL (r = 0.61, p = 0.001; r = 0.57, p = 0.001; r = 0.96, p = 0.001). The ratio of HHD and GD was very constant with 0.6 ± 0.07. These data indicate the high interindividual variability of glenoid morphology including significant gender-related differences. The good correlation between humeral head size and GD and maximum central PL can be helpful for cases with reduced bone stock in decision-making about implant size and bone grafting.

Different patterns of neuronal activities in the infralimbic and prelimbic cortices and behavioral expression in response to two affective odors, 2,5-dihydro-2,4,5-trimethylthiazoline and a mixture of cis-3-hexenol and trans-2-hexenal, in the freely moving rat.

PubMed

Nikaido, Y; Nakashima, T

2011-03-17

The medial prefrontal cortex (mPFC) is involved in stimulus perception, attentional control, emotional behavior, and the stress response. These functions are thought to be mediated by the infralimbic (IL) and prelimbic (PL) subregions of mPFC; however, few studies have examined the roles of IL and PL cortices in olfactory cognition. In the present study, we investigated the acute effects of two odors, 2,5-dihydro-2,4,5-trimethylthiazoline (TMT) and a mixture of cis-3-hexenol and trans-2-hexenal (green odor: GO), on behavioral responses and IL and PL neuronal activities using extracellular single-unit recordings in a freely moving rat. We found that the total number of spike firings in IL and PL neurons did not change with 10s presentation of odors. TMT presentation induced significant changes in burst firing activity in IL and PL neurons, while GO presentation induced changes in burst firing only in IL neurons. In the temporal profile of the firing activity of IL neurons, TMT exposure induced transient activation and GO exposure induced sustained activation. Those of PL neurons showed sustained activation during TMT exposure and transient activations during GO exposure. GO exposure induced a stretch-attend posture, whereas TMT exposure induced immobility. Furthermore, multiple regression analysis indicated that the property of the odor and neuronal activities of IL and PL regions were correlated with behavioral responses. These findings reveal that olfaction-related neurons exist in IL and PL regions, and that the neurons in these regions might temporarily encode odor information in order to modulate motor outputs by tuning firing properties in the early stage of cognition according to the odor property. Copyright © 2010 Elsevier B.V. All rights reserved.

[Effect of phospholipids containing omega-3 fatty acids on structural changes of microsomal lipids in cell membranes of functionally different cells].

PubMed

Datsenko, Z M; Volkov, H L; Kryvenko, O M; Nechytaĭlo, L O; Shovkun, S A; Khmel', T O; Perederiĭ, O F

2002-01-01

As a result of the experimental researches conducted it has been shown that administration of some normal animal marine phospholipids (PL) including in their structure omega-3 polyunsaturated fatty acids (PUFA) provides for quantitative changes of individual PL, fatty acids (FA) content and quantity in general and individual PL of liver, heart, brain and gonads microsomes. While estimating general microsomal PL fraction FA content under the action of PL omega-3 PUFA FA concentration change, unsaturation index (omega 6/omega 3) and relation of arachidonic acid to docosahexenic (AA/DHA) decrease have been identified. The decrease of AA/DHA relationship occurs due to AA and DHA quantitative changes. In the case of AA increase in some tissues there is observed the decrease of docosapentaenic acid and increase of DHA and eucosapentaenic (EPA) acidds. As a result of studying FA content in the individual PL composition it has been identified that certain PL classes characteristic for some tissues respond by changes of some certain FA. The relationship omega 6/omega 3 has been shown as decreasing in phosphatidilcholine (PC) all tissues microsomes (liver, gonads, heart, brain), in phosphatidilethanolamine (PEA) of liver and cardiac microsomes, in phosphatidilserine (PS) this relationship relationship decreases in the liver, brain and heart, for phosphatidilinositole (PI) the changes take place in liver, gonads, brain. Simultaneously, the decrease of AA/DHA relationship in the individual PL decrease of AA and increase of EPA and DHA depend on the tested tissues. The marine phospholipids might be supposed to render their effect on AA metabolism resulting in AA/DHA relationship in PEA and PS relationship displays itself as specific and depends on the tissues functions. The preference of PEA and PS use by certain tissues microsomes could be explained by their membrane protective capability.

[Cardiac abnormalities in patients with systemic lupus erythematosus: the role of antiphospholipid antibodies].

PubMed

Monti, Manuel; Borgognoni, Francesco; Pastacci, Loredana; Vincentelli, Giovanni Maria

2016-12-01

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease that has protean manifestations and follows a relapsing and remitting course. More than 90% of cases of SLE occur in women, frequently starting at childbearing age. It is characterized by the presence of autoantibodies potentially directed toward every organ or apparatus. Cardiac alterations are frequent in patients affected by SLE and the simultaneous presence of antiphospholipid antibodies (aPL), able to cause arterial thrombosis in any vascular district, is considered a possible risk factor for cardiac damage in SLE patients. The aim of this study is to correlate the main cardiac disorders, estimable through transthoracic echocardiography, in SLE patients as well as the typical autoantibody pattern of the disease. Our study included 76 patients: 38 SLE and 38 controls patients. Control patients have been properly selected to be comparable in gender, age and risks factors for cardiovascular disease. We performed autoantibody panel to assess the prevalence of various autoantibodies during SLE development (antinuclear antibody [ANA], double-stranded DNA [dsDNA], extractable nuclear antigen antibodies [ENA], aPL). In the study, the determination of the IgG and IgM isotypes for aPL (cardiolipin, phosphatidylinositol [aPI], phosphatidylserine, phosphatidic acid [aPA], and anti-β2-glycoprotein I antibodies) were checked. Echocardiography was performed in all patients. In patients affected by SLE, 94.7% was positive to ANA (relative risk 20; 95% confidence interval 4.9-340; p<0.0001) whereas 60.5% was positive for aPL. In patients with SLE, valvular alterations were observed, with a statistically significant correlation between mitral and aortic insufficiency (p=0.01 and p=0.02, respectively). Among aPL-positive patients, 68% (17/25) exhibited at least one hemodynamically significant echocardiographic alteration, vss 3/13 (23%) of patients with negative aPL, with a statistically significant correlation (relative risk 2; 95% confidence interval 1.0-29.8; p=0.01). Among positive-aPL patients, a statistically significant correlation was also observed between mitral insufficiency and aPI-IgG positivity (p=0.01) and, regarding non-valvular alterations, between left atrial enlargement and aPI-IgG positivity (p=0.01) and between left ventricular hypertrophy and aPA-IgG positivity (p=0.03). The present study confirms that SLE is an important risk factor for the presence of cardiac alterations, especially for valvular damage. Moreover, the presence of aPL antibodies in patients with SLE is significantly associated with an increased risk of heart disease, and some specific cardiac alterations are correlated with the positivity of some subclasses of aPL.

Platelet lysate activates quiescent cell proliferation and reprogramming in human articular cartilage: Involvement of hypoxia inducible factor 1.

PubMed

Nguyen, Van Thi; Cancedda, Ranieri; Descalzi, Fiorella

2018-03-01

The idea of rescuing the body self-repair capability lost during evolution is progressively gaining ground in regenerative medicine. In particular, growth factors and bioactive molecules derived from activated platelets emerged as promising therapeutic agents acting as trigger for repair of tissue lesions and restoration of tissue functions. Aim of this study was to assess the potential of a platelet lysate (PL) for human articular cartilage repair considering its activity on progenitor cells and differentiated chondrocytes. PL induced the re-entry in the cell cycle of confluent, growth-arrested dedifferentiated/progenitor cartilage cells. In a cartilage permissive culture environment, differentiated cells also resumed proliferation after exposure to PL. These findings correlated with an up-regulation of the proliferation/survival pathways ERKs and Akt and with an induction of cyclin D1. In short- and long-term cultures of articular cartilage explants, we observed a release of proliferating chondroprogenitors able to differentiate and form an "in vitro" tissue with properties of healthy articular cartilage. Moreover, in cultured cartilage cells, PL induced a hypoxia-inducible factor (HIF-1) alpha increase, its nuclear relocation and the binding to HIF-1 responsive elements. These events were possibly related to the cell proliferation because the HIF-1 inhibitor acriflavine inhibited HIF-1 binding to HIF-1 responsive elements and cell proliferation. Our study demonstrates that PL induces quiescent cartilage cell activation and proliferation leading to new cartilage formation, identifies PL activated pathways playing a role in these processes, and provides a rationale to the application of PL for therapeutic treatment of damaged articular cartilage. Copyright © 2017 John Wiley & Sons, Ltd.

Molecular Cloning and Functional Characterization of a Novel (Iso)flavone 4′,7-O-diglucoside Glucosyltransferase from Pueraria lobata

PubMed Central

Wang, Xin; Fan, Rongyan; Li, Jia; Li, Changfu; Zhang, Yansheng

2016-01-01

Pueraria lobata roots accumulate a rich source of isoflavonoid glycosides, including 7-O- and 4′-O-mono-glucosides, and 4′,7-O-diglucosides, which have numerous human health benefits. Although, isoflavonoid 7-O-glucosyltranferases (7-O-UGTs) have been well-characterized at molecular levels in legume plants, genes, or enzymes that are required for isoflavonoid 4′-O- and 4′,7-O-glucosylation have not been identified in P. lobata to date. Especially for the 4′,7-O-di-glucosylations, the genetic control for this tailing process has never been elucidated from any plant species. Through transcriptome mining, we describe here the identification and characterization of a novel UGT (designated PlUGT2) governing the isoflavonoid 4′,7-O-di-glucosylations in P. lobata. Biochemical roles of PlUGT2 were assessed by in vitro assays with PlUGT2 protein produced in Escherichia coli and analyzed for its qualitative substrate specificity. PlUGT2 was active with various (iso)flavonoid acceptors, catalyzing consecutive glucosylation activities at their O-4′ and O-7 positions. PlUGT2 was most active with genistein, a general isoflavone in legume plants. Real-time PCR analysis showed that PlUGT2 is preferentially transcribed in roots relative to other organs of P. lobata, which is coincident with the accumulation pattern of 4′-O-glucosides and 4′,7-O-diglucosides in P. lobata. The identification of PlUGT2 would help to decipher the P. lobata isoflavonoid glucosylations in vivo and may provide a useful enzyme catalyst for an efficient biotransformation of isoflavones or other natural products for food or pharmacological purposes. PMID:27066037

Effect of ambient oxygen on the photoluminescence of sol-gel-derived nanocrystalline ZrO2:Eu,Nb

NASA Astrophysics Data System (ADS)

Puust, Laurits; Kiisk, Valter; Eltermann, Marko; Mändar, Hugo; Saar, Rando; Lange, Sven; Sildos, Ilmo; Dolgov, Leonid; Matisen, Leonard; Jaaniso, Raivo

2017-06-01

The development of inorganic nanophosphors is an active research field due to many applications, including optical gas sensing materials. We found a systematic dependence of the photoluminescence (PL) of europium (Eu3+) impurity ions in zirconia (ZrO2) nanocrystals on the ambient oxygen concentration in a O2/N2 mixture at normal pressure. Europium-doped ZrO2 powders were synthesized via a sol-gel route. Heat-treatment at 1200 °C resulted in a well-developed monoclinic phase (XRD crystallite size of ~50 nm) and an intense PL of Eu3+ ions residing in the dominant phase (Eu3+ was excited directly at 395 or 464 nm). Co-doping with niobium resulted in a narrowing of the PL emission lines. Only Nb5+ was detected by XPS and is believed to charge-compensate Eu3+ activators throughout the material leading to a more regular crystal lattice. At room temperature, the exposure to oxygen suppressed the Eu3+ fluorescence, whereas, at elevated temperatures (300 °C), the effect was reversed. At 300 °C and under a focused continuous laser beam, a substantial PL response (>50%) was achieved when switching 100% of N2 for 100% of O2. PL decay kinetics clearly showed that at 300 °C fluorescence quenching centers were induced within the material by oxygen desorption. The relatively fast (<5 min) and sub-linear PL response to the changes of oxygen concentration shows that ZrO2:Eu,Nb is a promising PL-based oxygen sensing material over a wide-range of oxygen pressures.

Periodic assessment of plasma sFlt-1 and PlGF concentrations and its association with placental morphometry in gestational hypertension (GH) - a prospective follow-up study.

PubMed

Jeevaratnam, Kamalan; Nadarajah, Vishna Devi; Judson, John Paul; Nalliah, Sivalingam; Abdullah, Mohd Farouk

2010-09-28

Hypertensive disorders in pregnancy contributes to about 12% of maternal deaths in Malaysia and similarly worldwide. Early detection and adequate management are preventable strategies. Biochemical markers of abnormal angiogenesis would be more specific in early detection than routine blood pressure and proteinuria measurements. The aim of this study was to estimate maternal plasma PlGF and sFlt-1 levels in pregnant women with gestational hypertension at three intervals of pregnancy and correlate these biomarker levels with placental morphometry. Venous blood samples (antepartum, intrapartum and post partum periods) were drawn to estimate for sFlt-1 and PlGF levels while placental tissue samples were examined for placental morphometry. PlGF levels were lower in gestational hypertension (GH) compared to normotensive during antepartum and intrapartum period, whereas sFlt-1 levels were elevated in GH at antepartum, intrapartum and postpartum intervals during pregnancy. An inverse relationship between these two biomarkers was observed through correlation analysis. PlGF levels were inversely correlated with total villous surface area of the placental periphery (TCsa-C) and villous capillarization (VC-C) of the placental periphery. We established periodic values of for sFlt-1 and PlGF levels for the first time in an ethnically diverse Malaysian setting. We suggest the development of GH in women is related to defective capillarization. In demonstrating periodic changes, this study suggest the possibility of developing GH and other long term health complications as a result of prolonged exposure to sFlt-1. The correlation between PlGF levels and morphometric findings also support possible capillarization defect.

Laser exposure induced alteration of WS2 monolayers in the presence of ambient moisture

NASA Astrophysics Data System (ADS)

Atkin, P.; Lau, D. W. M.; Zhang, Q.; Zheng, C.; Berean, K. J.; Field, M. R.; Ou, J. Z.; Cole, I. S.; Daeneke, T.; Kalantar-Zadeh, K.

2018-01-01

Photoluminescence (PL) emergence in monolayer transition metal dichalcogenides (TMDs) such as WS2, has been one of the key attractions of such materials. However, there have been many observational contradictions in PL measurements presented in the past literature. This work addresses such issues. Firstly, the observational changes of the flakes’ PL patterns under exposure to various intensities of radiant exposure via laser sources are presented. These experiments show that these changes are a function of radiant exposure. Interestingly, it is observed that PL loss is accompanied by a change of the profile height for WS2 monolayers. In order to explore the fundamental mechanism for PL and height variations, laser irradiation was applied to monolayer WS2 flakes with varying radiant exposure to obtain PL maps, under the absence and presence of oxygen, H2O and nitrogen molecules in the atmosphere. It was seen that, after relatively high radiant exposure (>15 mJ µm-2), the PL pattern loss occurs only in the presence of atmospheric H2O molecules (45% humidity) and is also accompanied by an increase in height. Compositional analysis determined that this height increase was due to the substitution of surface S atoms with sulphate groups. This discovery represents an important step forward in understanding the necessary precautions when investigating optical properties of 2D TMDs in atmospheric conditions, and highlights the need for precise evaluation of the thresholds for radiant exposure at which specific reactions begin to occur. This knowledge is crucial for efficient and effective control of ambient operating conditions for optical characterisation of monolayer WS2 and TMDs in general.

Outcomes of photorefractive keratectomy following laser in situ keratomileusis: a cohort study.

PubMed

Iovieno, Alfonso; Teichman, Joshua C; Low, Stephanie; Yeung, Sonia N; Eve Lègarè, Marie; Lichtinger, Alejandro D; Slomovic, Allan R; Rootman, David S

2016-12-01

To analyze the outcomes of photorefractive keratectomy (PRK) on residual myopia and hyperopia post-laser in situ keratomileusis (LASIK) and to compare these results with PRK on eyes without previous laser refractive surgery. Retrospective comparative cohort study. Patients undergoing PRK between 2006 and 2010 were reviewed. Patients were divided into 4 groups, myopic or hyperopic PRK post-LASIK (mPRK-PL and hPRK-PL, respectively) and myopic or hyperopic PRK on corneas without previous laser refractive surgery (mPRK and hPRK, respectively). Uncorrected and corrected distance visual acuity, mean refractive spherical equivalent (MRSE), and mean keratometry and aberrations (total, higher order [HOA], coma, trefoil, and spherical aberration) were recorded at months 3 and 6 postoperatively, as were complications and attempted versus achieved MRSE. Thirty-three eyes of 25 patients who underwent PRK post-LASIK (21 eyes of 14 patients for hPRK-PL and 12 eyes of 11 patients for mPRK-PL) and 35 eyes of 21 patients who underwent PRK on virgin eyes (11 eyes of 8 patients for hPRK and 24 eyes of 13 patients for mPRK) were included in the study. The only significant differences in outcomes were found to be HOA at 3 months for hPRK-PL as compared with both hPRK and mPRK. Achieved MRSE was significantly different from expected MRSE for hPRK-PL at 3 months postoperatively. No haze- or flap-related complications were observed. Outcomes of PRK were not different in myopic and hyperopic corrections post-LASIK by 6 months or when compared with PRK in virgin eyes. HOA may render hPRK-PL results less predictable early in the postoperative period. Copyright © 2016 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Effect of Peptides' Binding on the Antimicrobial Activity and Biocompatibility of Protein-Based Substrates

NASA Astrophysics Data System (ADS)

Kaisersberger Vincek, Maja

This work reveals the effect of coupling approach (chemical by using carbodiimide chemistry and grafting-to vs. grafting-from synthesis routes, and enzymatic by using transglutaminase) of a hydrophilic epsilon-poly-L-lysine (epsilonPL) and an amphiphilic oligo-acyl-lysyl (OAK) derivative (K-7alpha 12-OH) to wool fibers and gelatine (GEL) macromolecules, respectively, and substrates antibacterial activity against Gram-negative E. coli and Gram-positive S. aureus bacteria after 1-24 h of exposure, as well as their cytotoxicity. Different spectroscopic (ultraviolet-visible, infrared, fluorescence and electron paramagnetic resonance) and separation techniques (size-exclusion chromatography and capillary zone electrophoresis) as well as zeta potential and potentiometric titration analysis, were performed to confirm the covalent coupling of epsilonPL/OAK, and to determine the amount and orientation of its immobilisation. The highest and kinetically the fastest level of bacterial reduction was achieved with wool/GEL functionalised with epsilonPL/OAK by chemical grafting-to approach. This effect correlated with both the highest grafting yield and conformationally the highly-flexible (brush-like) orientation linkage of epsilonPL/OAK, implicating on the highest amount of accessible amino groups interacting with bacterial membrane. However, OAK's amphipathic structure, the cationic charge and the hydrophobic moieties, resulted to relatively high reduction of S. aureus for grafting-from and the enzymatic coupling approaches using OAK-functionalised GEL. The epsilonPL/OAK-functionalised GEL did not induce toxicity in human osteoblast cells, even at 25-fold higher concentration than bacterial minimum inhibitory (MIC) concentration of epsilonPL/OAK, supporting their potential usage in biomedical applications. It was also shown that non-ionic surfactant adsorbs strongly onto the wool surface during the process of washing, thereby blocking the functional sites of immobilized epsilonPL and decreases its antibacterial efficiency.

[Diagnostic of ADHD in childhood and adolescence with the K-SADS-PL].

PubMed

Schmidt, Sören; Banaschewski, Tobias; Garbe, Edeltraut; Petermann, Franz; Petermann, Ulrike

2013-01-01

Attention Deficit-/Hyperactivity Disorder (ADHD) is one of the most prevalent psychiatric disorders in childhood and adolescence, often accompanied by comorbid disorders. A high standard of diagnostic assessment combined with a demand for valid diagnostic instruments is necessary. The K-SADS-PL is an established semi-structured interview, focusing on the categorical assessment of psychiatric disorders. The aim of the following study was to examine specific characteristics of ADHD symptomatology including functional and behavioral assessment. Therefore correlations between the result in a diagnostic interview (K-SADS-PL) and different ADHD-specific instruments were performed. Groups were formed (exposed vs. unexposed), based on the diagnostic finding in the K-SADS-PL. Group-specific test score differences were calculated and compared by multivariate analyses of covariance. Children with ADHD showed a significantly higher impact of conduct and emotional problems than the unexposed group. Health related quality of life was more impaired in children and families suffering from ADHD which refers to the relevance of family-oriented psychotherapy.

Method And Apparatus For Determining Health Of Thermal Barrier Coatings

DOEpatents

Srivastava, Alok Mani; Setlur, Anant Achyut; Comanzo, Holly Ann; Devitt, John William; Ruud, James Anthony; Brewer, Luke Nathaniel

2005-09-13

A method for determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating ("TBC") of the component comprises providing a photoluminescent ("PL") material in the TBC, directing an exciting radiation at the TBC, measuring the intensity of a characteristic peak in the emission spectrum of the PL material, and correlating the intensity of the characteristic peak or another quantity derived therefrom to an amount of a new phase that has been formed as a result of the exposure of the component to extreme temperatures. An apparatus for carrying out the method comprises a radiation source that provides the exciting radiation to the TBC, a radiation detector for detecting radiation emitted by the PL material, and means for relating a characteristic of the emission spectrum of the PL material to the amount of the new phase in the TBC, thereby inferring the past-service conditions or the remaining useful life of the component.

Impact of the oil industry on malaria diagnosis and management in north-east Scotland (1992-99).

PubMed

Mackenzie, A R; Laing, R B; Douglas, J G; Scott, N A; Smith, C C

2000-06-01

In order to assess the current pattern of malaria presenting to the Aberdeen Infection Unit a retrospective casenote review was undertaken of 110 patients admitted with that diagnosis between 1st January 1992 and 31st August 1999. Oil-related work was the reason for travel in 48 (43.6%) of the UK residents, holiday in 35 (31.8%), backpacking in 8 (7.3%) and other work in 5 (4.5%). Sixty-five patients (59.1%) had PL falciparum malaria (pure or mixed), 25 (22.7%) had PL vivax, 6 (5.4%) PL ovale and 3 (2.7%) PL malariae infection. No prophylaxis had been taken by 66% of the 47 UK-based oil workers and by 36% of the other 48 UK residents who had returned from Africa. There is a need for better education of oil workers and holidaymakers travelling to areas endemic for malaria. We are now setting up a travel advisory service in our Unit to address the problem.

Formation of size controlled Ge nanocrystals in Er-doped ZnO matrix and their enhancement effect in 1.54 μm photoluminescence

NASA Astrophysics Data System (ADS)

Fan, Ranran; Lu, Fei; Li, Kaikai; Liu, Kaijing

2018-06-01

This paper investigated the controllable growth of Ge nanocrystal (nc-Ge) in (Ge, Er) co-doped ZnO film, and the relationship between the size of nc-Ge and the enhancement of Er3+ related 1.54 μm photoluminescence (PL). It was found that nc-Ge with size of ∼5 nm was formed by annealing treatment at 600 °C. The intensity of 1.54 μm was significantly enhanced due to the existence of nc-Ge and showed an obvious dependence on nanocrystal size. The size of nc-Ge increased with the increase of the annealing temperature, and the nanocrystal with size of ∼5 nm made the most obvious contribution to PL enhancement. Prolonging annealing time could improve the crystalline structure of ZnO matrix but had no effect on PL intensity. The experimental results showed that the PL enhancement was mainly achieved by transferring the energy to Er through the resonance absorption of nc-Ge.

Photoluminescence and lasing properties of MAPbBr3 single crystals grown from solution

NASA Astrophysics Data System (ADS)

Aryal, Sandip; Lafalce, Evan; Zhang, Chuang; Zhai, Yaxin; Vardeny, Z. Valy

Recent studies of solution-grown single crystals of inorganic-organic hybrid lead-trihalide perovskites have suggested that surface traps may play a significant role in their photophysics. We study electron-hole recombination in single crystal MAPbBr3 through such trap states using cw photoluminescence (PL) and ps transient photoinduced absorption (PA) spectroscopies. By varying the depth of the collecting optics we examined the contributions from surface and bulk radiative recombination. We found a surface dominated PL band at the band-edge that is similar to that observed from polycrystalline thin films, as well as a weaker red-shifted emission band that originates from the bulk crystal. The two PL bands are distinguished in their temperature, excitation intensity and polarization dependencies, as well as their ps dynamics. Additionally, amplified spontaneous emission and crystal-related cavity lasing modes were observed in the same spectral range as the PL band assigned to the surface recombination. This work was funded by AFOSR through MURI Grant RA 9550-14-1-0037.

Oxygen related recombination defects in Ta{sub 3}N{sub 5} water splitting photoanode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Gao; Yu, Tao, E-mail: yscfei@nju.edu.cn, E-mail: yutao@nju.edu.cn; Zou, Zhigang

2015-10-26

A key route to improving the performance of Ta{sub 3}N{sub 5} photoelectrochemical film devices in solar driving water splitting to hydrogen is to understand the nature of the serious recombination of photo-generated carriers. Here, by using the temperature-dependent photoluminescence (PL) spectrum, we confirmed that for the Ta{sub 3}N{sub 5} films prepared by nitriding Ta{sub 2}O{sub 5} precursor, one PL peak at 561 nm originates from deep-level defects recombination of the oxygen-enriched Ta{sub 3}N{sub 5} phases, and another one at 580 nm can be assigned to band recombination of Ta{sub 3}N{sub 5} itself. Both of the two bulk recombination processes may decrease themore » photoelectrochemical performance of Ta{sub 3}N{sub 5}. It was difficult to remove the oxygen-enriched impurities in Ta{sub 3}N{sub 5} films by increasing the nitriding temperatures due to their high thermodynamically stability. In addition, a broadening PL peak between 600 and 850 nm resulting from oxygen related surface defects was observed by the low-temperature PL measurement, which may induce the surface recombination of photo-generated carriers and can be removed by increasing the nitridation temperature. Our results provided direct experimental evidence to understand the effect of oxygen-related crystal defects in Ta{sub 3}N{sub 5} films on its photoelectric performance.« less

Spatially Resolved X-ray Spectroscopy of the Large Magellanic Cloud Supernova Remnant N132D

NASA Astrophysics Data System (ADS)

Plucinsky, Paul; Sharda, Piyush; Gaetz, Terrance; Kashyap, Vinay

2018-01-01

We perform detailed X-ray spectroscopy of the brightest Supernova Remnant (SNR), N132D, in the Large Magellanic Cloud (LMC) using observations taken by the Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory (Chandra). By studying the spectra of regions on the well-defined rim running from NW to NE, we determine an average abundance set for O, Ne, Mg, Si, S and Fe for the local LMC environment. We note that the elements other than Fe and Ne show significant trends across this region, implying they cannot be approximated by a single, constant value. We characterize the blast wave properties and find a simple plane parallel shock model is sufficient to explain the X-ray spectrum of the forward shock moving into ambient LMC material, with a shock velocity near 800 km/s and a shock age of 600-1100 years. We find evidence of enhanced Si near the western blast wave which would imply an asymmetric explosion. We fit a region near the central, optical O-rich knots which exhibits enhanced abundances of O, Ne, Mg, Si, and Fe. Comparison to nucleosynthesis models of the ratios of these elements indicates a progenitor mass of 28-35 solar masses, consistent with most previous estimates. Lastly, we find an intriguing presence of a very hot plasma with a temperature of ~4.5 keV (assuming a non-equilibrium ionization model) to explain the Fe-K emission which is centrally concentrated in the lower half of the remnant.

The Evolution and Physical Parameters of WN3/O3s: A New Type of Wolf–Rayet Star

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neugent, Kathryn F.; Massey, Philip; Hillier, D. John

As part of a search for Wolf–Rayet (WR) stars in the Magellanic Clouds, we have discovered a new type of WR star in the Large Magellanic Cloud (LMC). These stars have both strong emission lines, as well as He ii and Balmer absorption lines and spectroscopically resemble a WN3 and O3V binary pair. However, they are visually too faint to be WN3+O3V binary systems. We have found nine of these WN3/O3s, making up ∼6% of the population of LMC WRs. Using cmfgen, we have successfully modeled their spectra as single stars and have compared the physical parameters with those ofmore » more typical LMC WNs. Their temperatures are around 100,000 K, a bit hotter than the majority of WN stars (by around 10,000 K), though a few hotter WNs are known. The abundances are what you would expect for CNO equilibrium. However, most anomalous are their mass-loss rates, which are more like that of an O-type star than a WN star. While their evolutionary status is uncertain, their low mass-loss rates and wind velocities suggest that they are not products of homogeneous evolution. It is possible instead that these stars represent an intermediate stage between O stars and WNs. Since WN3/O3 stars are unknown in the Milky Way, we suspect that their formation depends upon metallicity, and we are investigating this further by a deep survey in M33, which possesses a metallicity gradient.« less

The Catalina Surveys Southern periodic variable star catalogue

NASA Astrophysics Data System (ADS)

Drake, A. J.; Djorgovski, S. G.; Catelan, M.; Graham, M. J.; Mahabal, A. A.; Larson, S.; Christensen, E.; Torrealba, G.; Beshore, E.; McNaught, R. H.; Garradd, G.; Belokurov, V.; Koposov, S. E.

2017-08-01

Here, we present the results from our analysis of 6 yr of optical photometry taken by the Siding Spring Survey (SSS). This completes a search for periodic variable stars within the 30 000 deg2 of the sky covered by the Catalina Surveys. The current analysis covers 81 million sources with declinations between -20° and -75° with median magnitudes in the range 11 < V < 19.5. We find approximately 34 000 new periodic variable stars in addition to the ˜9000 RR Lyrae that we previously discovered in SSS data. This brings the total number of periodic variables identified in Catalina data to ˜110 000. The new SSS periodic variable stars mainly consist of eclipsing binaries, RR Lyrae, LPVs, RS CVn stars, δ Scutis, and Anomalous Cepheids. By cross-matching these variable stars with those from prior surveys, we find that ˜90 per cent of the sources are new discoveries and recover ˜95 per cent of the known periodic variables in the survey region. For the known sources, we find excellent agreement between our catalogue and prior values of luminosity, period, and amplitude. However, we find many variable stars that had previously been misclassified. Examining the distribution of RR Lyrae, we find a population associated with the Large Magellanic Cloud (LMC) that extends more than 20° from its centre confirming recent evidence for the existence of a very extended stellar halo in the LMC. By combining SSS photometry with Dark Energy Survey data, we identify additional LMC halo RR Lyrae, thus confirming the significance of the population.

The design of the local monitor and control system of SKA dishes

NASA Astrophysics Data System (ADS)

Schillirò, F.; Baldini, V.; Becciani, U.; Cirami, R.; Costa, A.; Ingallinera, A.; Marassi, A.; Nicotra, G.; Nocita, C.; Riggi, S.; Trigilio, C.

2016-08-01

The Square Kilometer Array (SKA) project aims at building the world's largest radio observatory to observe the sky with unprecedented sensitivity and collecting area. In the first phase of the project (SKA1), an array of dishes, SKA1-MID, will be built in South Africa. It will consist of 133 15m-dishes, which will include the MeerKAT array, for the 0.350-20 GHz frequency band observations. Each antenna will be provided with a local monitor and control system (LMC), enabling operations both to the Telescope Manager remote system, and to the engineers and maintenance staff; it provides different environment for the telescope control (positioning, pointing, observational bands), metadata collection for monitoring and database storaging, operational modes and functional states management for all the telescope capabilities. In this paper we present the LMC software architecture designed for the detailed design phase (DD), where we describe functional and physical interfaces with monitored and controlled sub-elements, and highlight the data flow between each LMC modules and its sub-element controllers from one side, and Telescope Manager on the other side. We also describe the complete Product Breakdown Structure (PBS) created in order to optimize resources allocation in terms of calculus and memory, able to perform required task for each element according to the proper requirements. Among them, time response and system reliability are the most important, considering the complexity of SKA dish network and its isolated placement. Performances obtained by software implementation using TANGO framework will be discussed, matching them with technical requirements derived by SKA science drivers.

Hubble Sees the Remains of a Star Gone Supernova

NASA Image and Video Library

2017-12-08

These delicate wisps of gas make up an object known as SNR B0519-69.0, or SNR 0519 for short. The thin, blood-red shells are actually the remnants from when an unstable progenitor star exploded violently as a supernova around 600 years ago. There are several types of supernovae, but for SNR 0519 the star that exploded is known to have been a white dwarf star — a Sun-like star in the final stages of its life. SNR 0519 is located over 150 000 light-years from Earth in the southern constellation of Dorado (The Dolphinfish), a constellation that also contains most of our neighboring galaxy the Large Magellanic Cloud (LMC). Because of this, this region of the sky is full of intriguing and beautiful deep sky objects. The LMC orbits the Milky Way galaxy as a satellite and is the fourth largest in our group of galaxies, the Local Group. SNR 0519 is not alone in the LMC; the NASA/ESA Hubble Space Telescope also came across a similar bauble a few years ago in SNR B0509-67.5, a supernova of the same type as SNR 0519 with a strikingly similar appearance. European Space Agency/NASA Hubble NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

MASSCLEANage-STELLAR CLUSTER AGES FROM INTEGRATED COLORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popescu, Bogdan; Hanson, M. M., E-mail: popescb@mail.uc.ed, E-mail: margaret.hanson@uc.ed

2010-11-20

We present the recently updated and expanded MASSCLEANcolors, a database of 70 million Monte Carlo models selected to match the properties (metallicity, ages, and masses) of stellar clusters found in the Large Magellanic Cloud (LMC). This database shows the rather extreme and non-Gaussian distribution of integrated colors and magnitudes expected with different cluster age and mass and the enormous age degeneracy of integrated colors when mass is unknown. This degeneracy could lead to catastrophic failures in estimating age with standard simple stellar population models, particularly if most of the clusters are of intermediate or low mass, like in the LMC.more » Utilizing the MASSCLEANcolors database, we have developed MASSCLEANage, a statistical inference package which assigns the most likely age and mass (solved simultaneously) to a cluster based only on its integrated broadband photometric properties. Finally, we use MASSCLEANage to derive the age and mass of LMC clusters based on integrated photometry alone. First, we compare our cluster ages against those obtained for the same seven clusters using more accurate integrated spectroscopy. We find improved agreement with the integrated spectroscopy ages over the original photometric ages. A close examination of our results demonstrates the necessity of solving simultaneously for mass and age to reduce degeneracies in the cluster ages derived via integrated colors. We then selected an additional subset of 30 photometric clusters with previously well-constrained ages and independently derive their age using the MASSCLEANage with the same photometry with very good agreement. The MASSCLEANage program is freely available under GNU General Public License.« less

A dearth of OH/IR stars in the Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

Goldman, Steven R.; van Loon, Jacco Th.; Gómez, José F.; Green, James A.; Zijlstra, Albert A.; Nanni, Ambra; Imai, Hiroshi; Whitelock, Patricia A.; Groenewegen, Martin A. T.; Oliveira, Joana M.

2018-01-01

We present the results of targeted observations and a survey of 1612-, 1665- and 1667-MHz circumstellar OH maser emission from asymptotic giant branch (AGB) stars and red supergiants (RSGs) in the Small Magellanic Cloud (SMC), using the Parkes and Australia Telescope Compact Array (ATCA) radio telescopes. No clear OH maser emission has been detected in any of our observations targeting luminous, long-period, large-amplitude variable stars, which have been confirmed spectroscopically and photometrically to be mid- to late-M spectral type. These observations have probed 3-4 times deeper than any OH maser survey in the SMC. Using a bootstrapping method with Large Magellanic Cloud (LMC) and Galactic OH/IR star samples and our SMC observation upper limits, we have calculated the likelihood of not detecting maser emission in any of the two sources considered to be the top maser candidates to be less than 0.05 per cent, assuming a similar pumping mechanism as the LMC and Galactic OH/IR sources. We have performed a population comparison of the Magellanic Clouds and used Spitzer IRAC and MIPS photometry to confirm that we have observed all high luminosity SMC sources that are expected to exhibit maser emission. We suspect that, compared to the OH/IR stars in the Galaxy and LMC, the reduction in metallicity may curtail the dusty wind phase at the end of the evolution of the most massive cool stars. We also suspect that the conditions in the circumstellar envelope change beyond a simple scaling of abundances and wind speed with metallicity.

Structural and Biochemical Analyses Reveal the Mechanism of Glutathione S-Transferase Pi 1 Inhibition by the Anti-cancer Compound Piperlongumine.

PubMed

Harshbarger, Wayne; Gondi, Sudershan; Ficarro, Scott B; Hunter, John; Udayakumar, Durga; Gurbani, Deepak; Singer, William D; Liu, Yan; Li, Lianbo; Marto, Jarrod A; Westover, Kenneth D

2017-01-06

Glutathione S-transferase pi 1 (GSTP1) is frequently overexpressed in cancerous tumors and is a putative target of the plant compound piperlongumine (PL), which contains two reactive olefins and inhibits proliferation in cancer cells but not normal cells. PL exposure of cancer cells results in increased reactive oxygen species and decreased GSH. These data in tandem with other information led to the conclusion that PL inhibits GSTP1, which forms covalent bonds between GSH and various electrophilic compounds, through covalent adduct formation at the C7-C8 olefin of PL, whereas the C2-C3 olefin of PL was postulated to react with GSH. However, direct evidence for this mechanism has been lacking. To investigate, we solved the X-ray crystal structure of GSTP1 bound to PL and GSH at 1.1 Å resolution to rationalize previously reported structure activity relationship studies. Surprisingly, the structure showed that a hydrolysis product of PL (hPL) was conjugated to glutathione at the C7-C8 olefin, and this complex was bound to the active site of GSTP1; no covalent bond formation between hPL and GSTP1 was observed. Mass spectrometry (MS) analysis of the reactions between PL and GSTP1 confirmed that PL does not label GSTP1. Moreover, MS data also indicated that nucleophilic attack on PL at the C2-C3 olefin led to PL hydrolysis. Although hPL inhibits GSTP1 enzymatic activity in vitro, treatment of cells susceptible to PL with hPL did not have significant anti-proliferative effects, suggesting that hPL is not membrane-permeable. Altogether, our data suggest a model wherein PL is a prodrug whose intracellular hydrolysis initiates the formation of the hPL-GSH conjugate, which blocks the active site of and inhibits GSTP1 and thereby cancer cell proliferation. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Structural and Biochemical Analyses Reveal the Mechanism of Glutathione S-Transferase Pi 1 Inhibition by the Anti-cancer Compound Piperlongumine*

PubMed Central

Harshbarger, Wayne; Gondi, Sudershan; Ficarro, Scott B.; Hunter, John; Udayakumar, Durga; Gurbani, Deepak; Singer, William D.; Liu, Yan; Li, Lianbo; Marto, Jarrod A.; Westover, Kenneth D.

2017-01-01

Glutathione S-transferase pi 1 (GSTP1) is frequently overexpressed in cancerous tumors and is a putative target of the plant compound piperlongumine (PL), which contains two reactive olefins and inhibits proliferation in cancer cells but not normal cells. PL exposure of cancer cells results in increased reactive oxygen species and decreased GSH. These data in tandem with other information led to the conclusion that PL inhibits GSTP1, which forms covalent bonds between GSH and various electrophilic compounds, through covalent adduct formation at the C7-C8 olefin of PL, whereas the C2-C3 olefin of PL was postulated to react with GSH. However, direct evidence for this mechanism has been lacking. To investigate, we solved the X-ray crystal structure of GSTP1 bound to PL and GSH at 1.1 Å resolution to rationalize previously reported structure activity relationship studies. Surprisingly, the structure showed that a hydrolysis product of PL (hPL) was conjugated to glutathione at the C7-C8 olefin, and this complex was bound to the active site of GSTP1; no covalent bond formation between hPL and GSTP1 was observed. Mass spectrometry (MS) analysis of the reactions between PL and GSTP1 confirmed that PL does not label GSTP1. Moreover, MS data also indicated that nucleophilic attack on PL at the C2-C3 olefin led to PL hydrolysis. Although hPL inhibits GSTP1 enzymatic activity in vitro, treatment of cells susceptible to PL with hPL did not have significant anti-proliferative effects, suggesting that hPL is not membrane-permeable. Altogether, our data suggest a model wherein PL is a prodrug whose intracellular hydrolysis initiates the formation of the hPL-GSH conjugate, which blocks the active site of and inhibits GSTP1 and thereby cancer cell proliferation. PMID:27872191

Fermi Gamma-Ray Observatory-Science Highlights for the First 8 Months

NASA Technical Reports Server (NTRS)

Moiseev, Alexander

2009-01-01

This viewgraph presentation reviews the science highlights for the first 8 months of the Fermi Gamma-Ray Observatory. Results from pulsars, flaring AGN, gamma ray bursts, diffuse radiation, LMC and electron spectrum are also presented.

High early strength latex modified concrete overlay.

DOT National Transportation Integrated Search

1988-01-01

This report describes the condition of the first high early strength latex modified concrete (LMC-HE) overlay to be constructed for the Virginia Department of Transportation. The overlay was prepared with type III cement and with more cement and less...

The evolution of rotating very massive stars with LMC composition

NASA Astrophysics Data System (ADS)

Köhler, K.; Langer, N.; de Koter, A.; de Mink, S. E.; Crowther, P. A.; Evans, C. J.; Gräfener, G.; Sana, H.; Sanyal, D.; Schneider, F. R. N.; Vink, J. S.

2015-01-01

Context. With growing evidence for the existence of very massive stars at subsolar metallicity, there is an increased need for corresponding stellar evolution models. Aims: We present a dense model grid with a tailored input chemical composition appropriate for the Large Magellanic Cloud (LMC). Methods: We use a one-dimensional hydrodynamic stellar evolution code, which accounts for rotation, transport of angular momentum by magnetic fields, and stellar wind mass loss to compute our detailed models. We calculate stellar evolution models with initial masses from 70 to 500 M⊙ and with initial surface rotational velocities from 0 to 550 km s-1, covering the core-hydrogen burning phase of evolution. Results: We find our rapid rotators to be strongly influenced by rotationally induced mixing of helium, with quasi-chemically homogeneous evolution occurring for the fastest rotating models. Above 160 M⊙, homogeneous evolution is also established through mass loss, producing pure helium stars at core hydrogen exhaustion independent of the initial rotation rate. Surface nitrogen enrichment is also found for slower rotators, even for stars that lose only a small fraction of their initial mass. For models above ~150 M⊙ at zero age, and for models in the whole considered mass range later on, we find a considerable envelope inflation due to the proximity of these models to their Eddington limit. This leads to a maximum ZAMS surface temperature of ~56 000 K, at ~180 M⊙, and to an evolution of stars in the mass range 50 M⊙...100 M⊙ to the regime of luminous blue variables in the Hertzsprung-Russell diagram with high internal Eddington factors. Inflation also leads to decreasing surface temperatures during the chemically homogeneous evolution of stars above ~180 M⊙. Conclusions: The cool surface temperatures due to the envelope inflation in our models lead to an enhanced mass loss, which prevents stars at LMC metallicity from evolving into pair-instability supernovae. The corresponding spin-down will also prevent very massive LMC stars to produce long-duration gamma-ray bursts, which might, however, originate from lower masses. The dataset of the presented stellar evolution models is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A71Appendices are available in electronic form at http://www.aanda.org