bluuebunny/crossref_metadata_2025 huggingface dataset:
The current status of the Nano-JASMINE project
Authors: Kobayashi Y. , Gouda N. , Yano T. , Suganuma M. , Yamauchi M. , Yamada Y. , Sako N. , Nakasuka S.
Published: July 2008

Nano-JASMINE is a nano-size astrometry satellite that will carry out astrometry measurements of nearby bright stars for more than one year. This will enable us to detect annual parallaxes of stars within 300 pc from the Sun. We expect the satellite to be launched as a piggy-back system as early as in 2009 into a Sun synchronized orbit at the altitude between 500 and 800 km. Being equipped with a beam combiner, the satellite has a capability to observe two different fields simultaneously and will be able to carry out HIPPARCOS-type observations along great circles. A 5 cm all aluminum made reflecting telescope with a aluminum beam combiner is developed. Using the on-board CCD controller, experiments with a real star have been executed. A communication band width is insufficient to transfer all imaging data, hence, we developed an onboard data processing system that extracts stellar image data from vast amount of imaging data. A newly developed 2K × 1K fully-depleted CCD will be used for the mission. It will work in the time delayed integration(TDI) mode. The bus system has been designed with special consideration of the following two points. Those are the thermal stabilization of the telescope and the accuracy of the altitude control. The former is essential to achieve high astrometric accuracies, on the order of 1 mas. Therefore relative angle of the beam combiner must be stable within 1 mas. A 3-axes control of the satellite will be realized by using fiber gyro and triaxial reaction wheel system and careful treatment of various disturbing forces.
Laser interferometric high-precision geometry (angle and length) monitor for JASMINE
Authors: Niwa Y. , Arai K. , Ueda A. , Sakagami M. , Gouda N. , Kobayashi Y. , Yamada Y. , Yano T.
Published: July 2008

The telescope geometry of JASMINE should be stabilized and monitored with the accuracy of about 10 to 100 pm or 10 to 100 prad of rms over about 10 hours. For this purpose, a high-precision interferometric laser metrology system is employed. Useful techniques for measuring displacements on extremely small scales are the wave-front sensing method and the heterodyne interferometrical method. Experiments for verification of measurement principles are well advanced.
Development of a very small telescope for a milli-arcsec space astrometry
Authors: Suganuma M. , Kobayashi Y. , Gouda N. , Yano T. , Yamada Y. , Takato N. , Yamauchi M.
Published: July 2008

We are preparing a reflecting telescope for Nano-JASMINE, a very small satellite for global space astrometry of milli-arcsecond accuracy. The telescope has a 5-cm diameter primary mirror and a beam-combiner in front of it. It occupies only about 12x12x17cm and is entirely made out of aluminum alloy. The telescope and its surrounding structures are carefully designed for thermal stability of the optics, especially to control changes in the relative angle of the beam-combiner.
Space Astrometry JASMINE
Authors: Yano T. , Gouda N. , Kobayashi Y. , Yamada Y. , Tsujimoto T. , Suganuma M. , Niwa Y. , Yamauchi M.
Published: July 2008

JASMINE is the acronym of the Japan Astrometry Satellite Mission for INfrared (z-band: 0.9 micron) Exploration, and is planned to be launched around 2017. The main objective of JASMINE is to study the fundamental structure and evolution of the Milky Way bulge components. In order to accomplish these objectives, JASMINE will measure trigonometric parallaxes, positions and proper motions of about ten million stars in the Galactic bulge with a precision of 10 microarcsec at z = 14mag.

The primary mirror for the telescope has a diameter of 75cm with a focal length of 22.5m. The back-illuminated CCD is fabricated on a 300 micron thick substrate which is fully depleted. These thick devices have extended near infrared response. The size of the detector for z-band is 3cm×3cm with 2048×2048 pixels. The size of the field of view is about 0.6deg×0.6deg by using 64 detectors on the focal plane. The telescope is designed to have only one field of view, which is different from the designs of other astrometric satellites. JASMINE will observe overlapping fields without gaps to survey a total area of about 20deg×10 deg around the Galactic bulge. Accordingly we make a “large frame” of 20deg×10 deg by linking the small frames using stars in overlapping regions. JASMINE will observe the Galactic bulge repeatedly during the mission life of about 5 years.
From the Roemer mission to Gaia
Authors: Høg E.
Published: July 2008

At the IAU symposium in Shanghai September 1992 the present author made the first proposal for a specific mission concept post-Hipparcos, the first scanning astrometry mission with CCDs in time-delayed integration mode (TDI). Direct imaging on CCDs in long-focus telescopes was described as later adopted for the Gaia mission. The mission called Roemer was designed to provide accurate astrometry and multi-colour photometry of 400 million stars brighter than 18 mag in a five-year mission. The early years of this mission concept are reviewed.
The Infrared Astrometry today
Authors: Kharin A. S. , Vedenicheva I. P. , Zolotukhina A. V.
Published: July 2008

Infrared Astrometry is one of the seven subdivisions of astrometry that detects emission in the range from 0.7 to 350 μm. Specific features and some problems of this one are discussed here and more details are provided on our web site “INFRARED ASTROMETRY” with the following URL http://www.mao.kiev.ua/IR. This web page includes 7 sections that will be expanded and regularly updated.
Asteroid astrometry as a link between ICRF and the Dynamical Reference Frames
Authors: Nedelcu D. A. , Souchay J. , Birlan M. , Popescu P. P. , Paraschiv P. V. , Badescu O.
Published: July 2008

Highly accurate astrometry of asteroids in the frame of QSOs will provide the direct link between the Dynamical Reference Frame and the International Celestial Reference Frame. We propose a procedure that implies a selection of events for asteroids with accurately determined orbits crossing the CCD field containing the selected quasars. For asteroid ephemerides, a numerical integration method coupled with precise modelling of asteroid brightness will be used for analyzing our observations. A list of predictions for this type of “close approaches” will be presented.
Multi-wavelength VLBI phase-delay astrometry of a complete sample of radio sources
Authors: Martí-Vidal I. , Marcaide J. M. , Guirado J. C.
Published: July 2008

We report on the first global high-precision (differential phase-delay) astrometric analyses performed on a complete set of radio sources. We have observed the S5 polar cap sample, consisting of 13 quasars and BL Lac objects, with the VLBA at 8.4, 15, and 43 GHz. We have developed new algorithms to enable the use of the differential phase-delay observable in global astrometric observations. From our global analyses, we determine the relative positions between all pairs of sources with typical precisions ranging from 10 to 200 μas, depending on observing frequency and source separation. In this paper, we discuss the impact of this observable in the enhancement of the astrometric precision. Since a large fraction of the S5 polar cap sources are ICRF defining sources, this may result in a test of the ICRF stability. Our multi-epoch/multi-frequency approach will also provide both absolute kinematics and spectral information of all sources in the sample. In turn, this will provide an important check on key predictions of the standard jet interaction model.
Solved and unsolved questions in the non-rigid Earth nutation study
Authors: Huang C. L.
Published: July 2008

At the IAU 26th GA held in Prague in 2006, a new precession model (P03) was recommended and adopted to replace the old one, IAU1976 precession model. This new P03 model is to match the IAU2000 nutation model that is for anelastic Earth model and was adopted in 2003 to replace the previous IAU1980 model. However, this IAU2000 nutation model is also not a perfect one for our complex Earth, as stated in the resolution of IAU nutation working group. The Earth models in the current nutation theories are idealized and too simple, far from the real one. They suffer from several geophysical factors: the an-elasticity of the mantle, the atmospheric loading and wind, the oceanic loading and current, the atmospheric and oceanic tides, the (lateral) heterogeneity of the mantle, the differential rotation between the inner core and the mantle, and various couplings between the fluid outer core and its neighboring solids (mantle and inner core). In this paper, first we give a very brief review of the current theoretical studies of non-rigid Earth nutation, and then focus on the couplings near the core-mantle boundary and the inner core-outer core boundary, including the electro-magnetic, viscous, topographic, and gravitational couplings. Finally, we outline some interesting future studies.
Radio interferometric tests of general relativity
Authors: Fomalont E. B. , Kopeikin S.
Published: July 2008

Since VLBI techniques produce a microarcsecond positional accuracy of celestial objects, tests of GR using radio sources as probes of a gravitational field have been made. We present the results from two recent tests using the VLBA: in 2005, the measurement of the classical solar deflection; and in 2002, the measurement of the retarded gravitational deflection associated with Jupiter. The deflection experiment measured γ to an accuracy of 3 × 10−4; the Jupiter experiment measured the retarded term to 20% accuracy. The controversy over the interpretation of the retarded term is summarized.
Preliminary investigation of the gravitomagnetic effects on the lunar orbit
Authors: Deng X. M.
Published: July 2008

Gravitomagnetic effects are studied in this paper. Starting from the metric in the BCRS and then using the matching method, the metric in the GCRS are derived. Furthermore, we give some estimation of the order of the gravitomagnetic effects on the lunar orbit.
Second post-Newtonian approximation of light propagation in Einstein-Aether theory
Authors: Xie Y. , Huang T. Y.
Published: July 2008

Future deep space laser ranging missions together with astrometry missions will be able to test relativistic gravity to an unprecedented level of accuracy and will require second post-Newtonian approximation of relevant theories of gravity. Einstein-aether theory is adopted as the theory of gravity and the second post-Newtonian approximation of light propagation is studied.
JASMINE data analysis
Authors: Yamada Y. , Gouda N. , Yano T. , Kobayashi Y. , Niwa Y. ,   JASMINE Working group
Published: July 2008

Japan Astrometry Satellite Mission for Infrared Exploration (JASMINE) aims to construct a map of the Galactic bulge with a 10 μasaccuracy. We use z-band CCD or K-band array detector to avoid dust absorption, and observe about 10 × 20 degrees area around the Galactic bulge region.

In this poster, we show the observation strategy, reduction scheme, and error budget. We also show the basic design of the software for the end-to-end simulation of JASMINE, named JASMINE Simulator.
Structure and kinematics of the Milky Way spirals traced by open clusters
Authors: Zhu Z.
Published: July 2008

Selecting 301 open clusters with complete spatial velocity measurements and ages, we are able to estimate the disk structure and kinematics of the Milky Way. Our analysis incorporates the disk scale height, the circular velocity of the Galactic rotation, the Galactocentric distance of the Sun and the ellipticity of the weak elliptical potential of the disk. We have derived the distance of the Sun to the Galactic center R0=8.03±0.70 kpc, that is in excellent agreement with the literature. From kinematic analysis, we found an age-dependent rotation of the Milky Way. The mean rotation velocity of the Milky Way is obtained as 235±10 km s−1. Using a dynamic model for an assumed elliptical disk, a clear weak elliptical potential of the disk with ellipticity of ε(R0) = 0.060±0.012 is detected, the Sun is found to be near the minor axis with a displacement of 30°±3°. The motion of clusters is suggested to be on elliptical orbits other than the circular rotation.
15 years of high precision astrometry in the Galactic Center
Authors: Gillessen S. , Genzel R. , Eisenhauer F. , Ott T. , Trippe S. , Martins F.
Published: July 2008

In 1992, we obtained the first observations of S2 a star close to the supermassive black hole at the Galactic Center. In 2002, S2 passed its periastron and in 2007, it completed a first fully observed revolution. This orbit allowed us to determine the mass of and the distance to the supermassive black hole with unprecedented accuracy. Here we present a re-analysis of the data set, enhancing the astrometric accuracy to 0.5 mas and increasing the number of well-determined stellar orbits to roughly 15. This allows to constrain the extended mass distribution around the massive black hole and will lead in the near future to the detection of post-Newtonian effects. We will also give an outlook on the potential of interferometric near-infrared astrometry with 10 microarcsecond accuracy from the VLTI.
Mass segregation effects in very young open clusters
Authors: Chen L. , de Grijs R. , Zhao J. L.
Published: July 2008

We derived proper motions and membership probabilities of stars in the regions of two very young (~ 2–4 Myr-old) open clusters NGC 2244 and NGC 6530. Both clusters show clear evidence of mass segregation, which provides strong support for the suggestion that the observed mass segregation is – at least partially – due to the way in which star formation has proceeded in these complex star-forming regions (“primordial” mass segregation).
Are parallaxes of long-period variable stars and red supergiants reliable?
Authors: Babusiaux C. , Jorissen A.
Published: July 2008

We have studied the impact of long-term variability and surface brightness asymmetries on the parallaxes of long-period variable stars and red supergiants.
Exploiting kinematics and UBVIc photometry to establish high fidelity membership of the open cluster Blanco 1
Authors: Cargile P. A. , James D. J. , Platais I. , Mermilliod J.-C. , Deliyannis C. , Steinhauer A.
Published: July 2008

We present the results of a wide-field, high-precision UBVIc CCD photometric survey of the Galactic open cluster Blanco 1. Standardized photometry was acquired using the Y4Kcam on the SMARTS 1m telescope at CTIO. We have also determined new high-precision proper motions (σμ = 0.3 mas yr−1) over an eight square degree area down to V = 16.5. Combined with 1D kinematic data, our survey yields a complete list of cluster members down to ~ 0.5 M⊙ and new high-fidelity color-magnitude diagrams are presented for Blanco 1. Having established a bona fide membership catalog, astrophysical characteristics of solar-type cluster members such as X-ray activity and lithium abundance have been studied to gain more insights in the process of internal mixing and convection. Our new results should also help to better understand its peculiar location in the Milky Way and to unravel its dynamical history.
Preliminary proper motion analysis of the Carina dwarf spheroidal
Authors: Carlin J. L. , Majewski S. R. , Casetti-Dinescu D.I. , Girard T. M.
Published: July 2008

We present preliminary results from a proper motion study of the Carina dwarf spheroidal galaxy. Our proper motions show a scatter of ~1.1 mas yr−1 per Carina member star, and we determinate the mean ensemble motion to an accuracy of ~7 mas century−1. While this is a precise measurement of the relative proper motions of Carina members, our correction to an absolute frame is limited by the small number of measured QSOs in the field.
Galactic kinematics near the sun from open clusters
Authors: Shen M.
Published: July 2008

A catalogue of open clusters is used to analyze the Galactic kinematics near the Sun. The Galactic open clusters, which are components of Galactic thin disk, were selected for our analysis. Based on kinematical data for around 270 Galactic open clusters, we found the Galactic rotation curve remains flat near the Sun. We also found Ve = 6.40±3.39 km s−1 inside the solar circle, which shows a weak trend of stars moving toward the Galactic anti-center.
The globular cluster tidal radii
Authors: Wu Z. Y.
Published: July 2008

The orbits and theoretical tidal radii for a sample of 45 Galactic globular clusters are calculated. The orbital phase dependence between the theoretical and observed tidal radii is noted.
Educating astrometry and celestial mechanics students for the 21st century
Authors: van Altena W. F. , Stavinschi M.
Published: July 2008

Astrometry and Celestial Mechanics have entered a new era with the advent of Micro-arcsecond positions, parallaxes and proper motions. Cutting-edge science topics will be addressed that were far beyond our grasp only a few years ago. It will be possible to determine definitive distances to Cepheid variables, the center of our Galaxy, the Magellanic Clouds and other Local Group members. We will measure the orbital parameters of dwarf galaxies that are merging with the Milky Way, define the kinematics, dynamics and structure of our Galaxy and search for evidence of the Dark Matter that makes up most of the mass in the universe. Stellar masses will be determined routinely to 1% accuracy and we will be able to make full orbit solutions and mass determinations for Extrasolar planetary systems. If we are to take advantage of Micro-arcsecond astrometry, we need to reformulate our study of reference frames, systems and the equations of motion in the context of special and general relativity. Methods also need to be developed to statistically analyze our data and calibrate our instruments to levels beyond current standards. As a consequence, our curricula must be drastically revised to meet the needs of students in the 21st Century. With the above considerations in mind, we developed a syllabus for an introductory one-semester course in Astrometry and Celestial Mechanics. This course gives broad introductions to most topics in our fields and a base of knowledge from which a student can elect areas for self-study or attendance at centers where advanced courses, workshops or internships are available.
A project of teaching ground-based astrometry
Authors: Arlot J.-E. , Jin W. J. , Zhu J. , Peng Q. Y. , Colas F. , Shen K. X. , Tang Z. H. , Zhu Z. , Lainey V. , Thuillot W. , Vienne A.
Published: July 2008

The optical ground-based astrometry of solar system objects may have its accuracy strongly improved by using new methods for making observations and reductions of them. New photometric methods of observating the mutual phenomena occurring in the solar system, may provide astrometric data with a higher precision than the classical direct imaging. In order to help preparing observers for the future campaigns of observations (2008–2010) and to promote this kind of high-accuracy astrometry, we plan to organize a spring school in 2008 in Beijing, China, for PhD and post-doctoral students, and for interested young astronomers.
The Gaia mission – a rich resource for outreach activities
Authors: O'Flaherty K. S. , Douglas J. , Prusti T.
Published: July 2008

Space science missions, and astronomy missions in particular, capture the public imagination at all levels. ESA's Gaia mission is no exception to this. In addition to its key scientific goal of providing new insight into the origin, formation, and evolution of the Milky Way, Gaia also touches on many other scientific topics of broad appeal, for example, solar system objects, stars (including rare and exotic ones), dark matter, gravitational light bending. The mission naturally provides a rich resource for outreach possibilities whether it be to the general public, or to specific interest groups, such as scientists from other fields or educators. We present some examples of possible outreach activities for Gaia.
Astrometry with digital sky surveys: from SDSS to LSST
Authors: Ivezić Ž. , Monet D. G. , Bond N. , Jurić M. , Sesar B. , Munn J. A. , Lupton R. H. , Gunn J. E. , Knapp G. R. , Tyson A. J. , Pinto P. , Cook K. ,   SDSS Collaboration and LSST Collaboration
Published: July 2008

Major advances in our understanding of the Universe have historically come from dramatic improvements in our ability to accurately measure astronomical quantities. The astrometric observations obtained by modern digital sky surveys are enabling unprecedentedly massive and robust studies of the kinematics of the Milky Way. For example, the astrometric data from the Sloan Digital Sky Survey (SDSS), together with half a century old astrometry from the Palomar Observatory Sky Survey (POSS), have enabled the construction of a catalog that includes absolute proper motions as accurate as 3 mas/year for about 20 million stars brighter than V=20, and for 80,000 spectroscopically confirmed quasars which provide exquisite error assessment. We discuss here several ongoing studies of Milky Way kinematics based on this catalog. The upcoming next-generation surveys will maintain this revolutionary progress. For example, we show using realistic simulations that the Large Synoptic Survey Telescope (LSST) will measure proper motions accurate to 1 mas/year to a limit 4 magnitude fainter than possible with SDSS and POSS catalogs, or with the Gaia survey. LSST will also obtain geometric parallaxes with accuracy similar to Gaia's at its faint end (0.3 mas at V=20), and extend them to V=24 with an accuracy of 3 mas. We discuss the impact that these LSST measurements will have on studies of the Milky Way kinematics, and potential synergies with the Gaia survey.
Understanding Self-Harm and Suicide Websites
Authors: Baker Darren , Fortune Sarah
Published: July 2008

Self-harm and suicide websites have been heavily criticized both in the literature and the wider media, despite the fact that very little is known about them. To date, no study has interviewed users of these sites about them. This qualitative study aims to explore the accounts of young adults who engage in self-harming and suicidal behaviors and use websites dedicated to these issues, in order to develop a broader understanding of these websites and to identify potential implications for future research. In-depth interviews were conducted via e-mail with 10 participants, who were recruited directly from self-harm and suicide websites. Using discourse analysis, we identified three main ways in which participants wrote about the sites. They constructed them as sources of empathy and understanding, as communities, and as a way of coping with social and psychological distress. These discourses gave users access to important, socially valued identities, such as being understood, belonging to a community and coping with their problems. If health professionals and researchers hope to understand people who use self-harm and suicide websites, and engage them in their services, they must take a more balanced view and not focus solely on the possible risks associated with using such sites.
Suicidal Behavior as Communication in a Cultural Context
Authors: Hjelmeland Heidi , Knizek Birthe Loa , Kinyanda Eugene , Musisi Seggane , Nordvik Hilmar , Svarva Kyrre
Published: July 2008

In this study, we attempt to even out some of the imbalance in suicide research caused by the fact that most such research has been conducted in the Western part of the world with the corresponding common disregard of the potential problems in generalizing findings to different cultural settings. Our point of departure was to look at suicidal behavior as communication and our main purpose was to investigate whether Qvortrups semiotic four-factor model, which has been empirically supported in the West, would be applicable in an African context, exemplified by Uganda. Interviews of patients admitted to hospital following an act of nonfatal suicidal behavior were conducted in Uganda and Norway and the data were compared. The results showed that the four-factor structure found in the West was not applicable in the Ugandan context, but that two by two of these factors were collapsed into a two-factor model in Uganda: One factor regarding the external dialog and one factor regarding the internal dialog. Some differences and some similarities were found between Norway and Uganda when suicidal behavior was considered as a communicative act. The results are discussed in terms of the differences in the psychological characteristics of the suicidal persons in the two countries, as well as the different cultural settings of the study.
Real-time detection of actively metabolizing microbes by redox sensing as applied to methylotroph populations in Lake Washington
Authors: Kalyuzhnaya Marina G , Lidstrom Mary E , Chistoserdova Ludmila
Published: July 2008

Redox sensor green (RSG), a novel fluorescent dye from Invitrogen was employed as a tool for real-time detection of microbes metabolically active in situ, in combination with flow cytometry and cell sorting. Lake Washington sediment, an environment known for high rates of methane oxidation, was used as a model, and methylotrophs were targeted as a functional group. We first tested and optimized the performance of the dye with pure methylotroph cultures. Most cells in actively growing cultures were positive for staining, whereas in starved cultures, few cells fluoresced. However, starved cells could be activated by addition of substrate. High numbers of fluorescing cells were observed in a Lake Washington sediment sample, and activation of subpopulations of cells was demonstrated in response to methane, methanol, methylamine and formaldehyde. The fraction of the population activated by methane was investigated in more detail, by phylogenetic profiling. This approach showed that the major responding species were the Methylomonas species, previously isolated from the site, and Methylobacter species that have not yet been cultivated from Lake Washington. In addition, from the methane-stimulated fraction, uncultivated bacterial sequences were obtained that belonged to unclassified Deltaproteobacteria, unclassified Verrucomicrobiles and unclassified Acidobacteria, suggesting that these microbes may also be involved in methane metabolism. The approach was further tested for its utility in facilitating enrichment for functional types that possess specific metabolic activities but resist cultivation. It was demonstrated that in enrichment cultures inoculated with cells that were sorted after stimulation with methane, Methylobacter sequences could be detected, whereas in enrichment cultures inoculated by randomly sorted cells, Methylomonas species quickly outcompeted all other types.
Ribophorin I regulates substrate delivery to the oligosaccharyltransferase core
Authors: Wilson Cornelia M. , Roebuck Quentin , High Stephen
Published: July 2008

Protein N-glycosylation is widespread among biological systems, and the fundamental process of transferring a lipid-linked glycan to suitable asparagine residues of newly synthesized proteins occurs in both prokaryotes and eukaryotes. The core reaction is mediated by Stt3p family members, and in many organisms this component alone is sufficient to constitute the so called oligosaccharyltransferase (OST). However, eukaryotes typically have a more elaborate OST with several additional subunits of poorly defined function. In the mammalian OST complex one such subunit, ribophorin I, is proposed to facilitate the N-glycosylation of certain precursors during their biogenesis at the endoplasmic reticulum. Here, we use cell culture models to show that ribophorin I depletion results in substrate-specific defects in N-glycosylation, clearly establishing a defined physiological role for ribophorin I. To address the molecular mechanism of ribophorin I function, a cross-linking approach was used to explore the environment of nascent glycoproteins during the N-glycosylation reaction. We show for the first time that ribophorin I can regulate the delivery of precursor proteins to the OST complex by capturing substrates and presenting them to the catalytic core.
IKK1 and IKK2 cooperate to maintain bile duct integrity in the liver
Authors: Luedde Tom , Heinrichsdorff Jan , de Lorenzi Rossana , De Vos Rita , Roskams Tania , Pasparakis Manolis
Published: July 2008

Inflammatory destruction of intrahepatic bile ducts is a common cause of vanishing bile duct syndrome and cholestasis, often progressing to biliary cirrhosis and liver failure. However, the molecular mechanisms underlying the pathogenesis of inflammatory biliary disease are poorly understood. Here, we show that the two IκB kinases, IKK1/IKKα and IKK2/IKKβ, display distinct collaborative and specific functions that are essential to protect the liver from cytokine toxicity and bile duct disease. Combined conditional ablation of IKK1 and IKK2, but not of each kinase alone, sensitized the liver to
in vivo
LPS challenge, uncovering a redundant function of the two IκB kinases in mediating canonical NF-κB signaling in hepatocytes and protecting the liver from TNF-induced failure. Unexpectedly, mice with combined ablation of IKK1 and IKK2 or IKK1 and NEMO spontaneously developed severe jaundice and fatal cholangitis characterized by inflammatory destruction of small portal bile ducts. This bile duct disease was caused by the combined impairment of canonical NF-κB signaling together with inhibition of IKK1-specific functions affecting the bile–blood barrier. These results reveal a novel function of the two IκB kinases in cooperatively regulating liver immune homeostasis and bile duct integrity and suggest that IKK signaling may be implicated in human biliary diseases.
Mucosal penetration primes
Vibrio cholerae
for host colonization by repressing quorum sensing
Authors: Liu Zhi , Miyashiro Tim , Tsou Amy , Hsiao Ansel , Goulian Mark , Zhu Jun
Published: July 2008

To successfully infect a host and cause the diarrheal disease cholera,
Vibrio cholerae
must penetrate the intestinal mucosal layer and express virulence genes. Previous studies have demonstrated that the transcriptional regulator HapR, which is part of the quorum sensing network in
V. cholerae
, represses the expression of virulence genes. Here, we show that
hapR
expression is also modulated by the regulatory network that governs flagellar assembly. Specifically, FliA, which is the alternative σ-factor (σ
28
) that activates late-class flagellin genes in
V. cholerae
, represses
hapR
expression. In addition, we show that mucin penetration by
V. cholerae
is sufficient to break flagella and so cause the secretion of FlgM, the anti-σ factor that inhibits FliA activity. During initial colonization of host intestinal tissue,
hapR
expression is repressed because of low cell density. However, full repression of
hapR
expression does not occur in
fliA
mutants, which results in attenuated colonization. Our results suggest that
V. cholerae
uses flagellar machinery to sense particular intestinal signals before colonization and enhance the expression of virulence genes by modulating the output of quorum sensing signaling.
Differential and chaotic calcium signatures in the symbiosis signaling pathway of legumes
Authors: Kosuta Sonja , Hazledine Saul , Sun Jongho , Miwa Hiroki , Morris Richard J. , Downie J. Allan , Oldroyd Giles E. D.
Published: July 2008

Understanding how the cell uses a limited set of proteins to transduce very different signals into specific cellular responses is a central goal of cell biology and signal transduction disciplines. Although multifunctionality in signal transduction is widespread, the mechanisms that allow differential modes of signaling in multifunctional signaling pathways are not well defined. In legume plants, a common symbiosis signaling pathway composed of at least seven proteins mediates infection by both mycorrhizal fungi and rhizobial bacteria. Here we show that the symbiosis signaling pathway in legumes differentially transduces both bacterial and fungal signals (inputs) to generate alternative calcium responses (outputs). We show that these differential calcium responses are dependent on the same proteins, DMI1 and DMI2, for their activation, indicating an inherent flexibility in this signaling pathway. By using Lyapunov and other mathematical analyses, we discovered that both bacterial-induced and fungal-induced calcium responses are chaotic in nature. Chaotic systems require minimal energy to produce a wide spectrum of outputs in response to marginally different inputs. The flexibility provided by chaotic systems is consistent with the need to transduce two different signals, one from rhizobial bacteria and one from mycorrhizal fungi, by using common components of a single signaling pathway.
Crystal and cryoEM structural studies of a cell wall degrading enzyme in the bacteriophage φ29 tail
Authors: Xiang Ye , Morais Marc C. , Cohen Daniel N. , Bowman Valorie D. , Anderson Dwight L. , Rossmann Michael G.
Published: July 2008

The small bacteriophage φ29 must penetrate the ≈250-Å thick external peptidoglycan cell wall and cell membrane of the Gram-positive
Bacillus subtilis
, before ejecting its dsDNA genome through its tail into the bacterial cytoplasm. The tail of bacteriophage φ29 is noncontractile and ≈380 Å long. A 1.8-Å resolution crystal structure of gene product 13 (gp13) shows that this tail protein has spatially well separated N- and C-terminal domains, whose structures resemble lysozyme-like enzymes and metallo-endopeptidases, respectively. CryoEM reconstructions of the WT bacteriophage and mutant bacteriophages missing some or most of gp13 shows that this enzyme is located at the distal end of the φ29 tail knob. This finding suggests that gp13 functions as a tail-associated, peptidoglycan-degrading enzyme able to cleave both the polysaccharide backbone and peptide cross-links of the peptidoglycan cell wall. Comparisons of the gp13
−
mutants with the φ29 mature and emptied phage structures suggest the sequence of events that occur during the penetration of the tail through the peptidoglycan layer.
SUMOylation of the MAGUK protein CASK regulates dendritic spinogenesis
Authors: Chao Hsu-Wen , Hong Chen-Jei , Huang Tzyy-Nan , Lin Yi-Ling , Hsueh Yi-Ping
Published: July 2008

Membrane-associated guanylate kinase (MAGUK) proteins interact with several synaptogenesis-triggering adhesion molecules. However, direct evidence for the involvement of MAGUK proteins in synapse formation is lacking. In this study, we investigate the function of calcium/calmodulin-dependent serine protein kinase (CASK), a MAGUK protein, in dendritic spine formation by RNA interference. Knockdown of CASK in cultured hippocampal neurons reduces spine density and shrinks dendritic spines. Our analysis of the time course of RNA interference and CASK overexpression experiments further suggests that CASK stabilizes or maintains spine morphology. Experiments using only the CASK PDZ domain or a mutant lacking the protein 4.1–binding site indicate an involvement of CASK in linking transmembrane adhesion molecules and the actin cytoskeleton. We also find that CASK is SUMOylated. Conjugation of small ubiquitin-like modifier 1 (SUMO1) to CASK reduces the interaction between CASK and protein 4.1. Overexpression of a CASK–SUMO1 fusion construct, which mimicks CASK SUMOylation, impairs spine formation. Our study suggests that CASK contributes to spinogenesis and that this is controlled by SUMOylation.
Inhibition of adipogenesis: a new job for the ER Ca2+ pool
Authors: Meldolesi Jacopo
Published: July 2008

Adipogenesis is the process of differentiation of adipocytes from mesenchymal multipotent cells through adipocyte precursors. In this issue, a study by the groups of Opas and Michalak (Szabo, E., Y. Qiu, S. Baksh, M. Michalak, and M. Opas. 2008. J. Cell. Biol. 182:103–116) demonstrates that this process is repressed by increasing intracellular Ca2+, which, in turn, is dependent on the expression of calreticulin, the major Ca2+-binding protein of the endoplasmic reticulum lumen.
Venous air embolism during the use of a Nd YAG laser
Authors: Aqil M. , Ulhaq A. , Arafat A. , Hussain A. , Rasheed A. , Turkistani A.
Published: July 2008

We report a case of a 47‐year‐old female who suffered a cardiac arrest during sub‐mucosal diathermy of the inferior turbinate using a Nd YAG laser. The possible causes of the cardiac arrest are discussed. Venous air embolism due to Nd YAG laser was thought to be the most likely cause in this case. Although venous air embolism has previously been reported during nasal sinus surgery and choanal atresia when using a Nd YAG laser, the occurrence of this complication during a relatively minor surgical procedure has not previously been reported. It is important, therefore, to raise the awareness of this life threatening complication during use of a Nd YAG laser regardless of the duration of surgery. We recommend the use of appropriate methods and techniques to avoid this life threatening complication during the use of Nd YAG laser even for relatively short procedures.
The effects of interrupted or continuous administration of sevoflurane on preconditioning before cardio‐pulmonary bypass in coronary artery surgery: comparison with continuous propofol
Authors: Bein B. , Renner J. , Caliebe D. , Hanss R. , Bauer M. , Fraund S. , Scholz J.
Published: July 2008

Volatile anaesthetics have been shown to exert cardioprotective properties in experimental and clinical studies. However, the mode of administration may influence these cardioprotective effects. The present study was designed to compare the effect of interrupted administration of sevoflurane before cardiopulmonary bypass with continuous sevoflurane administration and with propofol‐only anaesthesia, on cardioprotection as assessed by left ventricular performance and myocardial cell damage during coronary artery bypass grafting. Forty‐two patients scheduled for coronary bypass surgery were randomly assigned to one of three groups: propofol‐only (P; n = 14), continuous (SevoC; n = 14) and interrupted sevoflurane administration (SevoI; n = 14). Myocardial cell damage as assessed by Troponin T (cTNT) and creatine kinase MB (CK‐MB) were chosen as the primary endpoints and echocardiographic myocardial performance index (MPI) measurements were also performed. Up to 48 h postoperatively, in group SevoI, postoperative cTNT values (mean (SD) 0.13 (0.04) ng.ml−1) were significantly (p < 0.05) lower than both the P (0.26 (0.31) ng.ml−1) and SevoC (0.25 (0.17) ng.ml−1) groups. CK‐MB levels were also significantly (p < 0.05) lower in the SevoI group at 24 h after surgery and MPI significantly improved compared with both the P and SevoC groups. There was, however, no difference with respect to cytokine release and length of stay in either the intensive care unit or in the hospital. We conclude that prior interrupted sevoflurane administration confers some cardioprotection as compared with continuous sevoflurane administration or propofol‐based anaesthesia.
A procedure‐specific systematic review and consensus recommendations for postoperative analgesia following total knee arthroplasty
Authors: Fischer H. B. J. , Simanski C. J. P. , Sharp C. , Bonnet F. , Camu F. , Neugebauer E. A. M. , Rawal N. , Joshi G. P. , Schug S. A. , Kehlet H.
Published: July 2008

The PROSPECT Working Group, a collaboration of anaesthetists and surgeons, conducts systematic reviews of postoperative pain management for different surgical procedures (http://www.postoppain.org). Evidence‐based consensus recommendations for the effective management of postoperative pain are then developed from these systematic reviews, incorporating clinical practice observations, and transferable evidence from other relevant procedures. We present the results of a systematic review of pain and other outcomes following analgesic, anaesthetic and surgical interventions for total knee arthroplasty (TKA). The evidence from this review supports the use of general anaesthesia combined with a femoral nerve block for surgery and postoperative analgesia, or alternatively spinal anaesthesia with local anaesthetic plus spinal morphine. The primary technique, together with cooling and compression techniques, should be supplemented with paracetamol and conventional non‐steroidal anti‐inflammatory drugs or COX‐2‐selective inhibitors, plus intravenous strong opioids (high‐intensity pain) or weak opioids (moderate‐ to low‐intensity pain).
Population pharmacokinetic and pharmacodynamic modelling of the effects of nicorandil in the treatment of acute heart failure
Authors: Iida Satofumi , Kinoshita Haruki , Holford Nicholas H. G.
Published: July 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Nicorandil injection is used for unstable angina and for acute heart failure in Japan.

• The pharmacokinetics of nicorandil following oral administration have been described in healthy subjects.

WHAT THIS STUDY ADDS

• This paper describes the differences in nicorandil pharmacokinetics between healthy subjects and acute heart failure patients.

• A population pharmacokinetic‐pharmacodynamic model for nicorandil in acute heart failure patients is described using pulmonary artery wedge pressure as the biomarker.

• A rational guide for initial dosing of nicorandil to achieve a target effect on pulmonary artery wedge pressure was based on pharmacokinetic and pharmacodynamic principles.

AIMS

The aims of the study were 1) to evaluate the pharmacokinetics of nicorandil in healthy subjects and acute heart failure (AHF) patients and 2) to evaluate the exposure‐response relationship with pulmonary arterial wedge pressure (PAWP) in AHF patients and to predict an appropriate dosing regimen for nicorandil.

METHODS

Based on the data from two healthy volunteer and three AHF patient studies, models were developed to characterize the pharmacokinetics and pharmacodynamics of nicorandil. PAWP was used as the pharmacodynamic variable. An asymptotic exponential disease progression model was used to account for time dependent changes in PAWP that were not explained by nicorandil exposure. The modelling was performed using NONMEM version V.

RESULTS

The pharmacokinetics of nicorandil were characterized by a two‐compartment model with linear elimination. CL, V1 and V2 in AHF patients were 1.96, 1.39 and 4.06 times greater than in healthy subjects. Predicted plasma concentrations were assumed to have an immediate concentration effect relationship on PAWP. An inhibitory Emax model with Emax of −11.7 mmHg and EC50 of 423 µg l−1 was considered the best relationship between nicorandil concentrations and PAWP. PAWP decreased independently of nicorandil exposure. This drug independent decline was described by an asymptotic decrease of 6.1 mmHg with a half‐life of 5.3 h.

CONCLUSIONS

AHF patients have higher clearance and initial distribution volume of nicorandil compared with healthy subjects. The median target nicorandil concentration to decrease PAWP by 30% is predicted to be 748 µg l−1, indicating that a loading dose of 200 µg kg−1 and a maintenance dose of 400 µg kg−1 h−1 would be appropriate for the initial treatment of AHF.
Proteomic analysis of human bone marrow mesenchymal stem cells transduced with human telomerase reverse transcriptase gene during proliferation
Authors: Huang G. P. , Pan Z. J. , Huang J. P. , Yang J. F. , Guo C. J. , Wang Y. G. , Zheng Q. , Chen R. , Xu Y. L. , Wang G. Z. , Xi Y. M. , Shen D. , Jin J. , Wang J. F.
Published: July 2008

Abstract.  Objectives: Previous studies have reported immortalization and tumorigenicity of human mesenchymal stem cells (hMSCs) transduced with exogenous human telomerase reverse transcriptase (hTERT). We also have established a line of hMSCs transduced with hTERT (hTERT–hMSCs) and we have cultured these cells for 290 population doublings (PDs) during which they demonstrated a large proliferation potential but with no tumorigenicity. The aim of this study was to investigate the protein expression profile of hTERT–hMSCs with two‐dimensional gel electrophoresis and peptide mass fingerprinting by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, to be able to analyse the effects of exogenous hTERT on protein expression in hMSCs. Materials and methods: We generated proteome maps of primary hMSCs and hTERT–hMSCs at PD 95 and PD 275. Results: A total of 1543 ± 145 protein spots in gels of primary MSCs at PD 12, 1611 ± 186 protein spots in gels of hTERT–hMSCs at PD 95 and 1451 ± 126 protein spots in gels of hTERT–hMSCs at 275 PD were detected. One hundred of these were successfully identified, including 20 which were differentially expressed. Conclusions: The results suggest that sustaining levels of prohibitin and p53 expression along with differential expression of proteins in hTERT–hMSCs provide an insight into lack of transforming activity of hTERT–hMSCs during cell proliferation.
Phospholipase C‐delta extends intercellular signalling range and responses to injury‐released growth factors in non‐excitable cells
Authors: Mi L. Y. , Ettenson D. S. , Edelman E. R.
Published: July 2008

Abstract.  Objectives: Intercellular communication in non‐excitable cells is restricted to a limited range close to the signal source. Here, we have examined whether modification of the intracellular microenvironment could prolong the spatial proposition of signal generation and could increase cell proliferation. Material and methods: Mathematical models and experimental studies of endothelial repair after controlled mechanical injury were used. The models predict the diffusion range of injury‐released growth factors and identify important parameters involved in a signalling regenerative mode. Transfected human umbilical vein endothelial cells (HUVECs) were used to validate model results, by examining intercellular calcium signalling range, cell proliferation and wound healing rate. Results: The models predict that growth factors have a limited capacity of extracellular diffusion and that intercellular signals are specially sensitive to cell phospholipase C‐delta (PLCδ) levels. As basal PLCδ levels are increased by transfection, a significantly increased intercellular calcium range, enhanced cell proliferation, and faster wound healing rate were observed. Conclusion: Our in silico and in vitro studies demonstrated that non‐excitable endothelial cells respond to stimuli in a complex manner, in which intercellular communication is controlled by physicochemical properties of the stimulus and by the cell microenvironment. Such findings may have profound implications for our understanding of the tight nature of autocrine cell growth control, compensation to stress states and response to altered microenvironment, under pathological conditions.
The role of manager in children's homes: the process of managing and leading a well‐functioning staff team
Authors: Hicks Leslie
Published: July 2008

This paper is based on qualitative findings from a mixed methods project which investigated the roles of managers of children's homes and the relationship of these to their use of resources and the outcomes for young people in their care. The research formed part of the Costs and Effectiveness of Services to Children in Need research initiative, originally funded by the Department of Health. Main findings from the project overall and in particular from the multi‐level modelling analysis indicated that the influence which the process of providing care has on the kind of outcomes experienced by young people is of paramount importance. This paper provides a brief overview of the project and its aims. Drawing on the qualitative strand of the project and overall project findings, the paper investigates three aspects of managing children's homes: establishing working relationships with staff teams, the role of managers and bringing about working with the young people in their care. It situates the role of manager within the wider context of literature on leadership and investigates what leadership in children's homes entails. Finally, the paper highlights the importance of the role of manager in relationship to the development of good practice in children's homes.