81 research outputs found
The Use of Hybrid System of Classification for the retrieval and modification of Mechanical Products
ABSTRACT With people becoming more individualistic i
Determination of the amount of bioaccessible fumonisin B1 in different matrices after in vitro digestion
The slow component of the delayed rectifier potassium current in undiseased human ventricular myocytes
Objective: The purpose of this study was to investigate the properties of the slow component of the delayed rectifier potassium current (I-Ks) in myocytes isolated from undiseased human left ventricles. Methods: The whole-cell configuration of the patch-clamp technique was applied in 58 left ventricular myocytes from 15 hearts at 37 degreesC. Nisoldipine (1 muM) was used to block inward calcium current (I-Ca) and E-4031 (1-5 muM) was applied to inhibit the rapid component of the delayed rectifier potassium current (I-Ks). Results: In 31 myocytes an E-4031 insensitive, but L-735,821 and chromanol 293B sensitive, tail current was identified which was attributed to the slow component of I-K (I-Ks). Activation of I-Ks was slow (tau = 903 +/- 101 ms at 50 mV, n = 24), but deactivation of the current was relatively rapid ( tau =122.4 +/- 11.7 ms at -40 mV, n = 19). The activation of I-Ks was voltage independent but its deactivation showed clear voltage dependence. The deactivation was faster at negative voltages (about 100 ms at -50 mV) and slower at depolarized potentials (about 300 ms at 0 mV). In six cells, the reversal potential was -81.6 +/- 2.8 mV on an average which is close to the K+ equilibrium potential suggesting K+ as the main charge carrier. Conclusion: In undiseased human ventricular myocytes, I-Ks exhibits slow activation and fast deactivation kinetics. Therefore, in humans I-Ks differs from that reported in guinea pig, and it best resembles I-Ks described in dog and rabbit ventricular myocytes
X-ray structural analysis and antitumor activity of new salicylic acid derivatives
This Thesis project is going to be situated in my home town Ăstersund, 600 kilometers north from Stockholm.ItÂŽs a small town with 60 000 people and it is the only city of the region JĂ€mtland in Norrland, Sweden.In the city centre of Ăstersund there is one existing bus terminal station where the buses arrive with people from the entire region.The task for this Thesis project is to rebuild the existing bus station in Ăstersund where the actual terminal building is going to be completely demolished and the entire block within the current bus stops is going to be rearranged.The topography of the terminal area is now dividing the regional buses that arrives on the upper level from the city buses that stops at the lower level. Therefore the main challenge of the new proposal is how one would strengthen the junction between these two flows of people and how a new architecture could enable the encounter between the countryside and the urban city.Detta examensprojekt kommer att vara belĂ€gen i min hemstad Ăstersund, 600 kilometer norr om Stockholm. Det Ă€r en liten stad med 60 000 personer och det Ă€r den enda staden i regionen JĂ€mtland, Norrland. I centrum av Ăstersund finns en befintlig bussterminalen dĂ€r bussarna anlĂ€nder med folk frĂ„n hela regionen. Uppgiften för detta projekt Ă€r att bygga om den befintliga busstationen i Ăstersund topografin pĂ„ terminalomrĂ„det i dagslĂ€get separerar de regionala bussarna som anlĂ€nder pĂ„ den övre nivĂ„n frĂ„n stadsbussarna som stannar pĂ„ en lĂ€gre nivĂ„. Den största utmaningen i det nya förslaget Ă€r hur man istĂ€llet skulle kunna stĂ€rka förbindelsen mellan dessa tvĂ„ flöden av mĂ€nniskor och hur en ny arkitektur kan möjliggöra mötet mellan glesbyggd och den urbana staden
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Massive stars in extremely metal-poor galaxies: a window into the past
Cosmic history has witnessed the lives and deaths of multiple generations of massive stars, all of them invigorating their host galaxies with ionizing photons, kinetic energy, fresh material, and stellar-mass black holes. Ubiquitous engines as they are, astrophysics needs a good understanding of their formation, evolution, properties and yields throughout the history of the Universe, and with decreasing metal content mimicking the environment at the earliest epochs. Ultimately, a physical model that could be extrapolated to zero metallicity would enable tackling long-standing questions such as âWhat did the first, very massive stars of the Universe look like?â or âWhat was their role in the re-ionization of the Universe?â Yet, most of our knowledge of metal-poor massive stars is drawn from one single point in metallicity. Massive stars in the Small Magellanic Cloud (SMC, âŒ1/5Zâ ) currently serve as templates for low-metallicity objects in the early Universe, even though significant differences with respect to massive stars with poorer metal content have been reported. This White Paper summarizes the current knowledge on extremely (sub-SMC) metal poor massive stars, highlighting the most outstanding open questions and the need to supersede the SMC as standard. A new paradigm can be built from nearby extremely metal-poor galaxies that make a new metallicity ladder, but massive stars in these galaxies are out of reach to current observational facilities. Such a task would require an L-size mission, consisting of a 10m-class space telescope operating in the optical and the ultraviolet ranges. Alternatively, we propose that ESA unites efforts with NASA to make the LUVOIR mission concept a reality, thus continuing the successful partnership that made the Hubble Space Telescope one of the greatest observatories of all time
THESEUS::A key space mission concept for Multi-Messenger Astrophysics
The recent discovery of the electromagnetic counterpart of the gravitational
wave source GW170817, has demonstrated the huge informative power of
multi-messenger observations. During the next decade the nascent field of
multi-messenger astronomy will mature significantly. Around 2030, third
generation gravitational wave detectors will be roughly ten times more
sensitive than the current ones. At the same time, neutrino detectors currently
upgrading to multi km^3 telescopes, will include a 10 km^3 facility in the
Southern hemisphere that is expected to be operational around 2030. In this
review, we describe the most promising high frequency gravitational wave and
neutrino sources that will be detected in the next two decades. In this
context, we show the important role of the Transient High Energy Sky and Early
Universe Surveyor (THESEUS), a mission concept proposed to ESA by a large
international collaboration in response to the call for the Cosmic Vision
Programme M5 missions. THESEUS aims at providing a substantial advancement in
early Universe science as well as playing a fundamental role in multi-messenger
and time-domain astrophysics, operating in strong synergy with future
gravitational wave and neutrino detectors as well as major ground- and
space-based telescopes. This review is an extension of the THESEUS white paper
(Amati et al. 2017), also in light of the discovery of GW170817/GRB170817A that
was announced on October 16th, 2017.Comment: 25 pages, 13 figures, accepted to Advances in Space Research with
minor revisions. Details on the THESEUS instrumentation, science case and
expected performances can also be found in Amati et al. 2017
(arXiv:1710.04638) and in the presentations of the THESEUS Workshop 2017
(http://www.isdc.unige.ch/theseus/workshop2017-programme.html). v2 few typos
correcte
Massive stars in extremely metal-poor galaxies : a window into the past
Cosmic history has witnessed the lives and deaths of multiple generations of massive stars, all of them invigorating their host galaxies with ionizing photons, kinetic energy, fresh material, and stellar-mass black holes. Ubiquitous engines as they are, astrophysics needs a good understanding of their formation, evolution, properties and yields throughout the history of the Universe, and with decreasing metal content mimicking the environment at the earliest epochs. Ultimately, a physical model that could be extrapolated to zero metallicity would enable tackling long-standing questions such as âWhat did the first, very massive stars of the Universe look like?â or âWhat was their role in the re-ionization of the Universe?â Yet, most of our knowledge of metal-poor massive stars is drawn from one single point in metallicity. Massive stars in the Small Magellanic Cloud (SMC, âŒ1/5Zâ ) currently serve as templates for low-metallicity objects in the early Universe, even though significant differences with respect to massive stars with poorer metal content have been reported. This White Paper summarizes the current knowledge on extremely (sub-SMC) metal poor massive stars, highlighting the most outstanding open questions and the need to supersede the SMC as standard. A new paradigm can be built from nearby extremely metal-poor galaxies that make a new metallicity ladder, but massive stars in these galaxies are out of reach to current observational facilities. Such a task would require an L-size mission, consisting of a 10m-class space telescope operating in the optical and the ultraviolet ranges. Alternatively, we propose that ESA unites efforts with NASA to make the LUVOIR mission concept a reality, thus continuing the successful partnership that made the Hubble Space Telescope one of the greatest observatories of all time
The THESEUS space mission concept: science case, design and expected performances
THESEUS is a space mission concept aimed at exploiting Gamma-Ray Bursts for investigating the early Universe and at providing a substantial advancement of multi-messenger and time-domain astrophysics. These goals will be achieved through a unique combination of instruments allowing GRB and X-ray transient detection over a broad field of view (more than 1sr) with 0.5Âż1 arcmin localization, an energy band extending from several MeV down to 0.3ÂżkeV and high sensitivity to transient sources in the soft X-ray domain, as well as on-board prompt (few minutes) follow-up with a 0.7Âżm class IR telescope with both imaging and spectroscopic capabilities. THESEUS will be perfectly suited for addressing the main open issues in cosmology such as, e.g., star formation rate and metallicity evolution of the inter-stellar and intra-galactic medium up to redshift
10, signatures of Pop III stars, sources and physics of re-ionization, and the faint end of the galaxy luminosity function. In addition, it will provide unprecedented capability to monitor the X-ray variable sky, thus detecting, localizing, and identifying the electromagnetic counterparts to sources of gravitational radiation, which may be routinely detected in the late ¿20s/early ¿30s by next generation facilities like aLIGO/ aVirgo, eLISA, KAGRA, and Einstein Telescope. THESEUS will also provide powerful synergies with the next generation of multi-wavelength observatories (e.g., LSST, ELT, SKA, CTA, ATHENA).© 2018 COSPARS.E. acknowledges the financial support from contracts ASI-INAF 1/009/10/0, NARO15 ASI-INAF 1/037/12/0 and ASI 2015-046-R.0. R.H. acknowledges GACR grant 13-33324S. S.V. research leading to these results has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 606176. D.S. was supported by the Czech grant 1601116S GA CR. Maria Giovanna Dainotti acknowledges funding from the European Union through the Marie Curie Action FP7-PEOPLE-2013-IOF, under grant agreement No. 626267 (>Cosmological Candles>)
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