100 research outputs found
Modeling of extreme freshwater outflow from the north-eastern Japanese river basins to western Pacific Ocean
This study demonstrates the importance of accurate extreme discharge input in hydrological and oceanographic combined modeling by introducing two extreme typhoon events. We investigated the effects of extreme freshwater outflow events from river mouths on sea surface salinity distribution (SSS) in the coastal zone of the north-eastern Japan. Previous studies have used observed discharge at the river mouth, as well as seasonally averaged inter-annual, annual, monthly or daily simulated data. Here, we reproduced the hourly peak discharge during two typhoon events for a targeted set of nine rivers and compared their impact on SSS in the coastal zone based on observed, climatological and simulated freshwater outflows in conjunction with verification of the results using satellite remote-sensing data. We created a set of hourly simulated freshwater outflow data from nine first-class Japanese river basins flowing to the western Pacific Ocean for the two targeted typhoon events (Chataan and Roke) and used it with the integrated hydrological (CDRMV3.1.1) and oceanographic (JCOPE-T) model, to compare the case using climatological mean monthly discharges as freshwater input from rivers with the case using our hydrological model simulated discharges. By using the CDRMV model optimized with the SCE-UA method, we successfully reproduced hindcasts for peak discharges of extreme typhoon events at the river mouths and could consider multiple river basin locations. Modeled SSS results were verified by comparison with Chlorophyll-a distribution, observed by satellite remote sensing. The projection of SSS in the coastal zone became more realistic than without including extreme freshwater outflow. These results suggest that our hydrological models with optimized model parameters calibrated to the Typhoon Roke and Chataan cases can be successfully used to predict runoff values from other extreme precipitation events with similar physical characteristics. Proper simulation of extreme typhoon events provides more realistic coastal SSS and may allow a different scenario analysis with various precipitation inputs for developing a nowcasting analysis in the future
Life Beyond the Solar System: Space Weather and Its Impact on Habitable Worlds
The search of life in the Universe is a fundamental problem of astrobiology
and a major priority for NASA. A key area of major progress since the NASA
Astrobiology Strategy 2015 (NAS15) has been a shift from the exoplanet
discovery phase to a phase of characterization and modeling of the physics and
chemistry of exoplanetary atmospheres, and the development of observational
strategies for the search for life in the Universe by combining expertise from
four NASA science disciplines including heliophysics, astrophysics, planetary
science and Earth science. The NASA Nexus for Exoplanetary System Science
(NExSS) has provided an efficient environment for such interdisciplinary
studies. Solar flares, coronal mass ejections and solar energetic particles
produce disturbances in interplanetary space collectively referred to as space
weather, which interacts with the Earth upper atmosphere and causes dramatic
impact on space and ground-based technological systems. Exoplanets within close
in habitable zones around M dwarfs and other active stars are exposed to
extreme ionizing radiation fluxes, thus making exoplanetary space weather (ESW)
effects a crucial factor of habitability. In this paper, we describe the recent
developments and provide recommendations in this interdisciplinary effort with
the focus on the impacts of ESW on habitability, and the prospects for future
progress in searching for signs of life in the Universe as the outcome of the
NExSS workshop held in Nov 29 - Dec 2, 2016, New Orleans, LA. This is one of
five Life Beyond the Solar System white papers submitted by NExSS to the
National Academy of Sciences in support of the Astrobiology Science Strategy
for the Search for Life in the Universe.Comment: 5 pages, the white paper was submitted to the National Academy of
Sciences in support of the Astrobiology Science Strategy for the Search for
Life in the Univers
Impact of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets
The current progress in the detection of terrestrial type exoplanets has
opened a new avenue in the characterization of exoplanetary atmospheres and in
the search for biosignatures of life with the upcoming ground-based and space
missions. To specify the conditions favorable for the origin, development and
sustainment of life as we know it in other worlds, we need to understand the
nature of astrospheric, atmospheric and surface environments of exoplanets in
habitable zones around G-K-M dwarfs including our young Sun. Global environment
is formed by propagated disturbances from the planet-hosting stars in the form
of stellar flares, coronal mass ejections, energetic particles, and winds
collectively known as astrospheric space weather. Its characterization will
help in understanding how an exoplanetary ecosystem interacts with its host
star, as well as in the specification of the physical, chemical and biochemical
conditions that can create favorable and/or detrimental conditions for
planetary climate and habitability along with evolution of planetary internal
dynamics over geological timescales. A key linkage of (astro) physical,
chemical, and geological processes can only be understood in the framework of
interdisciplinary studies with the incorporation of progress in heliophysics,
astrophysics, planetary and Earth sciences. The assessment of the impacts of
host stars on the climate and habitability of terrestrial (exo)planets will
significantly expand the current definition of the habitable zone to the
biogenic zone and provide new observational strategies for searching for
signatures of life. The major goal of this paper is to describe and discuss the
current status and recent progress in this interdisciplinary field and to
provide a new roadmap for the future development of the emerging field of
exoplanetary science and astrobiology.Comment: 206 pages, 24 figures, 1 table; Review paper. International Journal
of Astrobiology (2019
Validation of a novel radiation mapping platform for the reduction of operator-induced shielding effects
Living donor liver transplantation using sensitized lymphocytotoxic crossmatch positive graft
We describe a successful living donor liver transplantation (LDLT) using a lymphocytotoxic crossmatch highly positive graft. A 41-year-old woman with alcoholic liver cirrhosis was referred as a potential candidate for LDLT, and her husband was willing to donate his partial liver. As the T-lymphocytotoxic crossmatch titer was over 10,000×, the patient was first infused with rituximab for preoperative desensitization, and then five rounds of plasmapheresis were performed. After the third plasmapheresis, the lymphocytotoxic crossmatch test was negative. A left liver graft including the caudate lobe was implanted, and anti-CD25 antibody (basiliximab) was administered on postoperative days 1 and 4. The postoperative course was uneventful except for an episode of mild acute cellular rejection on postoperative day 27. Although the impact of a lymphocytotoxic crossmatch-positive liver graft on acute cellular rejection and graft survival in LDLT remains controversial, perioperative desensitization may provide benefits when using a highly sensitized liver graft
Identification of α(1,6)fucosylated proteins differentially expressed in human colorectal cancer
<p>Summary</p> <p>Background</p> <p>A universal hallmark of cancer cells is the change in their glycosylation phenotype. One of the most frequent alterations in the normal glycosylation pattern observed during carcinogenesis is the enhancement of α(1,6)linked fucose residues of glycoproteins, due to the up-regulation of the α(1,6)fucosyltransferase activity. Our previous results demonstrated the specific alteration of this enzyme activity and expression in colorectal cancer, suggesting its implication in tumour development and progression.</p> <p>Methods</p> <p>In the current work we combined a LCA-affinity chromatography with SDS-PAGE and mass spectrometry in order to identify α(1,6)fucosylated proteins differentially expressed in colorectal cancer. This strategy allowed the identification of a group of α(1,6)fucosylated proteins candidates to be involved in CRC malignancy.</p> <p>Results</p> <p>The majority of the identified proteins take part in cell signaling and interaction processes as well as in modulation of the immunological response. Likewise, we confirmed the increased expression of GRP94 in colorectal cancer tissue and the significant down-regulation of the IgGFcBP expression in tumour cells.</p> <p>Conclusion</p> <p>All these results validate the importance of <it>core-</it>fucosylated proteins profile analysis to understand the mechanisms which promote cancer onset and progression and to discover new tumour markers or therapeutic targets.</p
Cobalamin in inflammation III — glutathionylcobalamin and methylcobalamin/adenosylcobalamin coenzymes: the sword in the stone? How cobalamin may directly regulate the nitric oxide synthases
Several mysteries surround the structure and function of the nitric oxide synthases (NOS). The NOS oxygenase domain structure is unusually open with a large area of solvent that could accommodate an unidentified ligand. The exact mechanism of the two-step five-electron monoxygenation of arginine to NG-hydroxy-L-arginine, thence to citrulline and nitric oxide (NO), is not clear, particularly as arginine/NG-hydroxy-L-arginine is bound at a great distance to the supposed catalytic heme Fe [III], as the anti-stereoisomer. The Return of the Scarlet Pimpernel Paper proposed that cobalamin is a primary indirect regulator of the NOS. An additional direct regulatory effect of the ‘base-off’ dimethylbenzimidazole of glutathionylcobalamin (GSCbl), which may act as a sixth ligand to the heme iron, promote Co-oriented, BH4/BH3 radical catalysed oxidation of L-arginine to NO, and possibly regulate the rate of inducible NOS/NO production by the NOS dimers, is further advanced. The absence of homology between the NOS and methionine synthase/methylmalonyl CoA mutase may enable GSCbl to regulate both sets of enzymes simultaneously by completely separate mechanisms. Thus, cobalamin may exert central control over both pro-and anti-inflammatory systems
The diagnostic accuracy of US, CT, MRI and 1H-MRS for the evaluation of hepatic steatosis compared with liver biopsy: a meta-analysis
OBJECTIVE: To meta-analyse the diagnostic accuracy of US, CT, MRI and (1)H-MRS for the evaluation of hepatic steatosis. METHODS: From a comprehensive literature search in MEDLINE, EMBASE, CINAHL and Cochrane (up to November 2009), articles were selected that investigated the diagnostic performance imaging techniques for evaluating hepatic steatosis with histopathology as the reference standard. Cut-off values for the presence of steatosis on liver biopsy were subdivided into four groups: (1) >0, >2 and >5% steatosis; (2) >10, >15 and >20%; (3) >25, >30 and >33%; (4) >50, >60 and >66%. Per group, summary estimates for sensitivity and specificity were calculated. The natural-logarithm of the diagnostic odds ratio (lnDOR) was used as a single indicator of test performance. RESULTS: 46 articles were included. Mean sensitivity estimates for subgroups were 73.3-90.5% (US), 46.1-72.0% (CT), 82.0-97.4% (MRI) and 72.7-88.5% ((1)H-MRS). Mean specificity ranges were 69.6-85.2% (US), 88.1-94.6% (CT), 76.1-95.3% (MRI) and 92.0-95.7% ((1)H-MRS). Overall performance (lnDOR) of MRI and (1)H-MRS was better than that for US and CT for all subgroups, with significant differences in groups 1 and 2. CONCLUSION: MRI and (1)H-MRS can be considered techniques of choice for accurate evaluation of hepatic steatosi
- …