6,311 research outputs found
Index to NASA Tech Briefs, January - June 1967
Technological innovations for January-June 1967, abstracts and subject inde
Index to NASA Tech Briefs, January - June 1966
Index to NASA technological innovations for January-June 196
LPS-induced TNF-α factor mediates pro-inflammatory and pro-fibrogenic pattern in non-alcoholic fatty liver disease
Lipopolysaccharide (LPS) is currently considered one of the major players in non-alcoholic fatty liver disease (NAFLD) pathogenesis and progression. Here, we aim to investigate the possible role of LPS-induced TNF-α factor (LITAF) in inducing a pro-inflammatory and pro-fibrogenic phenotype of non-alcoholic steatohepatitis (NASH).We found that children with NAFLD displayed, in different liver-resident cells, an increased expression of LITAF which correlated with histological traits of hepatic inflammation and fibrosis. Total and nuclear LITAF expression increased in mouse and human hepatic stellate cells (HSCs). Moreover, LPS induced LITAF-dependent transcription of IL-1β, IL-6 and TNF-α in the clonal myofibroblastic HSC LX-2 cell line, and this effect was hampered by LITAF silencing. We showed, for the first time in HSCs, that LITAF recruitment to these cytokine promoters is LPS dependent. However, preventing LITAF nuclear translocation by p38MAPK inhibitor, the expression of IL-6 and TNF-α was significantly reduced with the aid of p65NF-ĸB, while IL-1β transcription exclusively required LITAF expression/activity. Finally, IL-1β levels in plasma mirrored those in the liver and correlated with LPS levels and LITAF-positive HSCs in children with NASH.In conclusion, a more severe histological profile in paediatric NAFLD is associated with LITAF over-expression in HSCs, which in turn correlates with hepatic and circulating IL-1β levels outlining a panel of potential biomarkers of NASH-related liver damage. The in vitro study highlights the role of LITAF as a key regulator of the LPS-induced pro-inflammatory pattern in HSCs and suggests p38MAPK inhibitors as a possible therapeutic approach against hepatic inflammation in NASH
Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) VIII. A less biased view of the early co-evolution of black holes and host galaxies
We present ALMA [CII] line and far-infrared (FIR) continuum observations of
three low-luminosity quasars () discovered by our
Subaru Hyper Suprime-Cam (HSC) survey. The [CII] line was detected in all three
targets with luminosities of , about one order
of magnitude smaller than optically luminous ()
quasars. The FIR continuum luminosities range from
(3 limit) to , indicating a wide range
in star formation rates in these galaxies. Most of the HSC quasars studied thus
far show [CII]/FIR luminosity ratios similar to local star-forming galaxies.
Using the [CII]-based dynamical mass () as a surrogate for bulge
stellar mass (), we find that a significant fraction of
low-luminosity quasars are located on or even below the local relation, particularly at the massive end of the galaxy mass
distribution. In contrast, previous studies of optically luminous quasars have
found that black holes are overmassive relative to the local relation. Given
the low luminosities of our targets, we are exploring the nature of the early
co-evolution of supermassive black holes and their hosts in a less biased way.
Almost all of the quasars presented in this work are growing their black hole
mass at much higher pace at than the parallel growth model, in which
supermassive black holes and their hosts grow simultaneously to match the local
relation at all redshifts. As the low-luminosity
quasars appear to realize the local co-evolutionary relation even at , they should have experienced vigorous starbursts prior to the currently
observed quasar phase to catch up with the relation.Comment: 19 pages, 11 figures, 4 tables. Accepted for publication in
Publications of the Astronomical Society of Japan (PASJ
The Pointing System of the Herschel Space Observatory. Description, Calibration, Performance and Improvements
We present the activities carried out to calibrate and characterise the
performance of the elements of attitude control and measurement on board the
Herschel spacecraft. The main calibration parameters and the evolution of the
indicators of the pointing performance are described, from the initial values
derived from the observations carried out in the performance verification phase
to those attained in the last year and half of mission, an absolute pointing
error around or even below 1 arcsec, a spatial relative pointing error of some
1 arcsec and a pointing stability below 0.2 arsec. The actions carried out at
the ground segment to improve the spacecraft pointing measurements are
outlined. On-going and future developments towards a final refinement of the
Herschel astrometry are also summarised. A brief description of the different
components of the attitude control and measurement system (both in the space
and in the ground segments) is also given for reference. We stress the
importance of the cooperation between the different actors (scientists, flight
dynamics and systems engineers, attitude control and measurement hardware
designers, star-tracker manufacturers, etc.) to attain the final level of
performance.Comment: 28 pages, 8 figures, accepted for publication in Experimental
Astronom
Focal Plane Alignment and Detector Characterization for the Subaru Prime Focus Spectrograph
We describe the infrastructure being developed to align and characterize the
detectors for the Subaru Measurement of Images and Redshifts (SuMIRe) Prime
Focus Spectrograph (PFS). PFS will employ four three-channel spectrographs with
an operating wavelength range of 3800 to 12600 . Each spectrograph
will be comprised of two visible channels and one near infrared (NIR) channel,
where each channel will use a separate Schmidt camera to image the captured
spectra onto their respective detectors. In the visible channels, Hamamatsu 2k
x 4k CCDs will be mounted in pairs to create a single 4k x 4k detector, while
the NIR channel will use a single Teledyne 4k x 4k H4RG HgCdTe device.Comment: 16 pages, 27 figures, SPIE ATI Montreal 201
Triple redundant hydrogen sensor with in situ calibration
To meet sensing and calibration needs, an in situ calibration technique was developed. It is based on electrolytic generation of a hydrogen/air atmosphere within a hydrogen sensor. The hydrogen is generated from water vapor in the air, and being electrical in nature, the in situ calibration can be performed completely automatically in remote locations. Triply redundant sensor elements are integrated within a single, compact housing, and digital logic provides inter-sensor comparisons to warn of and identify malfunctioning sensor elements. An evaluation of this concept is presented
High-speed craft (HSC) : a study of their safe operation and navigation, and their impact upon the Malacca Strait
The dissertation is a study of the safe operation and navigation of High-speed Craft (HSC) and their impact upon the Malacca Strait. The definitions of HSC are compared and illustrated. The future trend, growth and development of current types of HSC and their inherent design limitations are investigated. The maneuvering systems and characteristics of HSC are analyzed. The active safety system employed by HSC is compared to the passive safety system of conventional vessels. The operation and navigation problems due to high-speed are investigated. The human resource management methods of reducing human errors are discussed. The navigational requirements of the HSC Code are reviewed to determine its weaknesses. The difficulties in various operational environments and the importance of appropriate aids to navigation are discussed. The collision avoidance techniques used by HSC operators are examined to determine their impact on the Colregs. Relevant rules affected by these techniques are discussed with a view of suggesting possible solutions. The factors affecting the development of HSC services in the littoral states of Malacca Strait are explored. Particular reference is made to developments in Malaysia. A brief look is taken at the marine environment in the Malacca Strait. The proposals by the littoral states to the International Maritime Organization to enhance the safety of navigation and the protection of the marine environment are considered for further improvement. Additionally, training methodology for HSC operators by a number of institutions is also investigated. The concluding chapters examine the results of the study and recommendations are made concerning the need to revise Chapter 13 of the HSC Code and the International Convention for Preventing Collisions at Sea. Proposals are also made regarding the need to improve the aids to navigation and the safety of navigation in the Malacca Strait
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