Full-size solar dynamic heat receiver thermal-vacuum tests

The testing of a full-size, 120 kW, solar dynamic heat receiver utilizing high-temperature thermal energy storage is described. The purpose of the test program was to quantify receiver thermodynamic performance, operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partly simulate a low-Earth-orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to allow axially and circumferentially varied flux distributions. A closed-Brayton cycle engine simulator conditioned a helium-xenon gas mixture to specific interface conditions to simulate the various operational modes of the solar dynamic power module on the Space Station Freedom. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles, each 94 minutes in duration, was completed during the test conduct period

Ground test program for a full-size solar dynamic heat receiver

Test hardware, facilities, and procedures were developed to conduct ground testing of a full size, solar dynamic heat receiver in a partially simulated, low Earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment were designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed Brayton cycle engine simulator to circulate and condition the helium xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described

Neuropsychologic function in toddlers exposed to cocaine in utero: A preliminary study

Patterns of neuropsychological performance on A-not-B, inhibition, motor, cognitive, language, and behavior tasks were examined in 34 toddlers--17 cocaine-exposed (CE) and 17 nonexposed (NE) controls. CE toddlers exhibited greater perseveration, less inhibition, poorer emotional regulation, and less task orientation relative to NE toddlers. Overall cognitive and language skills and motor impairment status were comparable among CE and NE toddlers. Differences in perseveration, emotional regulation, and task orientation between CE and NE toddlers remained significant after statistically controlling for overall cognitive skill. Prenatal cocaine exposure may impart selective vulnerability for deficits in executive function, inhibition, and emotional regulation in toddlers, perhaps related to the concurrent rapid frontal lobe maturation and the neurobiology of cocaine. Furthermore, these findings suggest that performance can be broken down into meaningful neuropsychological components in very young children

Die solitäre abszedierende Osteomyelitis des Kieferköpfchens: Eine Rarität

Zusammenfassung: Fall: Es wird über den seltenen Fall einer solitären abszedierenden, sekundär chronischen Osteomyelitis des linken Processus condylaris berichtet. Aus dem Abszessmaterial wurde der Keim Haemophilus aphrophilus isoliert. Therapeutisch erfolgte eine Resektion des Processus condylaris mit Sofortrekonstruktion des Kondylus mithilfe einer Kopfendoprothese. Diskussion: Mögliche Ursachen für diese seltene Lokalisation einer sekundär chronischen Osteomyelitis werden anhand der Literatur aufgearbeitet und dem vorliegenden Fall gegenübergestellt. Schlussfolgerung: Als mögliche Ursache wird eine Keiminokulation durch die Nadel bei einer Lokalanästhesie, eine bakterielle Kontamination während der Zahnextraktion oder eine hämatogene Aussaat durch den Extraktionsvorgang angenomme

Broadband multi-wavelength campaign on PKS 2005-489

The spectral energy distribution (SED) of high-frequency peaked BL Lac objects (HBL) is characterized by two peaks: one in the UV-X-ray and one in the GeV-TeV regime. An interesting object for analyzing these broadband characteristics is PKS 2005-489, which in 2004 showed the softest TeV spectrum ever measured. In 2009, a multi-wavelength campaign has been conducted with, for the first time, simultaneous observations by H.E.S.S. (TeV), Fermi/LAT (GeV), RXTE (keV), Swift (keV, UV, optical) and ATOM (optical) to cover the two peaks of the SED. During this campaign PKS 2005-489 underwent a high state in all wavebands which gives the opportunity to study in detail the emission processes of a high state of this interesting HBL.Comment: 2009 Fermi Symposium; eConf Proceedings C09112

Die kondyläre Metastasierung: Literaturrecherche und ein Fallbericht

Zusammenfassung: Hintergrund: Kondyläre Metastasen sind eine Rarität. In der Literaturrecherche entsprachen nur 23 der insgesamt 69 gefundenen Fälle den Kriterien von Meyer u. Shklar. Fallbericht: Bei einem 48-jährigen Mann mit Schmerzen im linken Kiefergelenk wurde im linken Kondylus eine solitäre Metastase eines kurz zuvor operierten Lungenkarzinoms gefunden. Aufgrund der ausgedehnten Umgebungsinfiltration erfolgte eine kurative Radiatio. Im Verlauf traten weitere Skelettmetastasen auf. Diskussion: Kieferköpfchenmetastasen unterscheiden sich bezüglich ihres Verlaufs kaum von den Metastasen des extraartikulären Kieferbereiches. Unter den metastasierenden Tumoren rangiert das Mammakarzinom als Primärtumor an erster Stelle, gefolgt vom Lungenkarzinom. Klinisch und radiologisch können keine spezifischen Parameter für eine Diagnosestellung angegeben werden. Bei der Differenzialdiagnostik der Gelenkserkrankungen sollte jedoch insbesondere bei Patienten mit bekannten Primärtumoren und Gelenksbeschwerden sowie radiologischen Auffälligkeiten eine mögliche Metastasierung berücksichtigt werden. Die Diagnose sollte für eine entsprechende Therapieplanung histologisch gesichert werden. Das therapeutische Vorgehen ist in der Regel palliativ, da die Grunderkrankung bei Diagnosestellung einer Kieferköpfchenmetastase zumeist weit fortgeschritten is

Observations of OJ 287 from the Geodetic VLBI Archive of the Washington Correlator

We present 27 geodetic VLBI maps of OJ 287 obtained from the archive of the Washington correlator. The observations presented here were made between 1990 October and 1996 December. During this period a sequence of six superluminal components has been identified. We measured the proper motion of these components to be approximately 0.5 mas/yr, which is about twice as high as that seen in previous VLBI observations. These results imply a higher component ejection rate than previously observed, in good agreement with the observed occurrences of radio outbursts. We have examined a possible connection between VLBI components and optical flares in the framework of a binary black hole system.Comment: 9 pages, 5 included figures, emulateapj.sty, accepted to The Astrophysical Journa

Unidentified Galactic High-Energy Sources as Ancient Pulsar Wind Nebulae in the light of new high energy observations and the new code

In a Pulsar Wind Nebula (PWN), the lifetime of inverse Compton (IC) emitting electrons exceeds the lifetime of its progenitor pulsar (as well as its shell-type remnant), but it also exceeds the age of those that emit via synchrotron radiation. Therefore, during its evolution, the PWN can remain bright in IC so that its GeV-TeV gamma-ray flux remains high for timescales much larger (for 10^5 - 10^6 yrs) than the pulsar lifetime and the X-ray PWN lifetime. In this scenario, the magnetic field in the cavity induced by the wind of the progenitor star plays a crucial role. This scenario is in line with the discovery of several unidentified or "dark" sources in the TeV gamma-ray band without X-ray counterparts; and it is also finding confirmation in the recent discoveries at GeV gamma rays. Moreover, these consequences could be also important for reinterpreting the detection of starburst galaxies in the TeV gamma-ray band when considering a leptonic origin of the gamma-ray signal. Both theoretical aspects and their observational proofs will be discussed, as well as the first results of our new modeling code.Comment: Proceedings of the 5th International Symposium on High-Energy Gamma-Ray Astronomy (Gamma2012

Toxicity of statins on rat skeletal muscle mitochondria

Abstract.: We investigated mitochondrial toxicity of four lipophilic stains (cerivastatin, fluvastatin, atorvastatin, simvastatin) and one hydrophilic statin (pravastatin). In L6 cells (rat skeletal muscle cell line), the four lipophilic statins (100μmol/l) induced death in 27-49% of the cells. Pravastatin was not toxic up to 1mmol/l. Cerivastatin, fluvastatin and atorvastatin (100μmol/l) decreased the mitochondrial membrane potential by 49-65%, whereas simvastatin and pravastatin were less toxic. In isolated rat skeletal muscle mitochondria, all statins, except pravastatin, decreased glutamate-driven state 3 respiration and respiratory control ratio. Beta-oxidation was decreased by 88-96% in the presence of 100μmol/l of the lipophilic statins, but only at higher concentrations by pravastatin. Mitochondrial swelling, cytochrome c release and DNA fragmentation was induced in L6 cells by the four lipophilic statins, but not by pravastatin. Lipophilic statins impair the function of skeletal muscle mitochondria, whereas the hydrophilic pravastatin is significantly less toxi

Tricritical Behavior in Charge-Order System

Tricritical point in charge-order systems and its criticality are studied for a microscopic model by using the mean-field approximation and exchange Monte Carlo method in the classical limit as well as by using the Hartree-Fock approximation for the quantum model. We study the extended Hubbard model and show that the tricritical point emerges as an endpoint of the first-order transition line between the disordered phase and the charge-ordered phase at finite temperatures. Strong divergences of several fluctuations at zero wavenumber are found and analyzed around the tricritical point. Especially, the charge susceptibility chi_c and the susceptibility of the next-nearest-neighbor correlation chi_R are shown to diverge and their critical exponents are derived to be the same as the criticality of the susceptibility of the double occupancy chi_D0. The singularity of conductivity at the tricritical point is clarified. We show that the singularity of the conductivity sigma is governed by that of the carrier density and is given as |sigma-sigma_c|=|g-g_c|^{p_t}Alog{|g-g_{c}|}+B), where g is the effective interaction of the Hubbard model, sigma_c g_c represents the critical conductivity(interaction) and A and B are constants, respectively. Here, in the canonical ensemble, we obtain p_t=2beta_t=1/2 at the tricritical point. We also show that p_t changes into p_{t}'=2beta=1 at the tricritical point in the grand-canonical ensemble when the tricritical point in the canonical ensemble is involved within the phase separation region. The results are compared with available experimental results of organic conductor (DI-DCNQI)2Ag.Comment: 20 pages, 32 figures, to appear in J. Phys. Soc. Jpn. Vol.75(2006)No.