621 research outputs found
Atmospheric fluctuations below 0.1 Hz during drift-scan solar diameter measurements
Measurements of the power spectrum of the seeing in the range 0.001-1 Hz have
been performed in order to understand the criticity of the transits' method for
solar diameter monitoring.Comment: 3 pages, 3 figures, proc. of the Fourth French-Chinese meeting on
Solar Physics Understanding Solar Activity: Advances and Challenges, 15 - 18
November, 2011 Nice, Franc
COVID-19 Vaccination Status among Adults Admitted to Intensive Care Units in Veneto, Italy
: This cohort study examines admissions to intensive care units for COVID-19–associated acute respiratory distress syndrome by COVID-19 vaccination status among adults in the Veneto region of Italy from May to December 2021
Sensitive gravity-gradiometry with atom interferometry: progress towards an improved determination of the gravitational constant
We here present a high sensitivity gravity-gradiometer based on atom
interferometry. In our apparatus, two clouds of laser-cooled rubidium atoms are
launched in fountain configuration and interrogated by a Raman interferometry
sequence to probe the gradient of gravity field. We recently implemented a
high-flux atomic source and a newly designed Raman lasers system in the
instrument set-up. We discuss the applications towards a precise determination
of the Newtonian gravitational constant G. The long-term stability of the
instrument and the signal-to-noise ratio demonstrated here open interesting
perspectives for pushing the measurement precision below the 100 ppm level
Precision measurements of gravity using cold atom sensors
We present a synthetic view of experiments we are performing using atom interferometry to determine the gravitational constant G and to test the Newtonian gravitational law at micrometric distances. Accurate gravity measurements with atom interferometry also find applications in geophysical studies and in satellite missions for the geoid mapping. Experiments in progress, using ultracold atom devices, for applications in geophyiscal and space monitoring will be also described
Synthesis and preliminary in vitro evaluation of DOTA-Tenatumomab conjugates for theranostic applications in tenascin expressing tumors
Tenatumomab is an anti-tenascin murine monoclonal antibody previously used in clinical trials for delivering radionuclides to tumors by both pre-targeting (biotinylated Tenatumomab within PAGRIT) and direct 131Iodine labeling approaches. Here we present the synthesis and in vitro characterization of three Tenatumomab con-jugates to bifunctional chelating agents (NHS-DOTA, NCS-DOTA and NCS-DTPA). Results indicate ST8198AA1(Tenatumomab-DOTAMA, derived by conjugation of NHS-DOTA), as the most promising candidate in terms ofconjugation rate andyield, stability,antigenimmunoreactivity andaffinity. Labeling efficiency of thedifferentchelators was investigated with a panel of cold metals indicating DOTAMA as the best chelator. Labeling ofTenatumomab-DOTAMA was then optimized with several metals and stability performed confirms suitability of this conjugate for further development. ST8198AA1 represents an improvement of the previous antibody forms because the labeling with radionuclides like177Lu or64Cu would allow theranostic applications in patientsbearing tenascin expressing tumor
Dissociation of the benzene molecule by UV and soft X-rays in circumstellar environment
Benzene molecules, present in the proto-planetary nebula CRL 618, are ionized
and dissociated by UV and X-ray photons originated from the hot central star
and by its fast wind. Ionic species and free radicals produced by these
processes can lead to the formation of new organic molecules. The aim of this
work is to study the photoionization and photodissociation processes of the
benzene molecule, using synchrotron radiation and time of flight mass
spectrometry. Mass spectra were recorded at different energies corresponding to
the vacuum ultraviolet (21.21 eV) and soft X-ray (282-310 eV) spectral regions.
The production of ions from the benzene dissociative photoionization is here
quantified, indicating that C6H6 is more efficiently fragmented by soft X-ray
than UV radiation, where 50% of the ionized benzene molecules survive to UV
dissociation while only about 4% resist to X-rays. Partial ion yields of H+ and
small hydrocarbons such as C2H2+, C3H3+ and C4H2+ are determined as a function
of photon energy. Absolute photoionization and dissociative photoionization
cross sections have also been determined. From these values, half-life of
benzene molecule due to UV and X-ray photon fluxes in CRL 618 were obtained.Comment: The paper contains 8 pages, 9 figures and 4 tables. Accepted to be
published on MNRAS on 2008 November 2
Precision Measurement of the Newtonian Gravitational Constant Using Cold Atoms
About 300 experiments have tried to determine the value of the Newtonian
gravitational constant, G, so far, but large discrepancies in the results have
made it impossible to know its value precisely. The weakness of the
gravitational interaction and the impossibility of shielding the effects of
gravity make it very difficult to measure G while keeping systematic effects
under control. Most previous experiments performed were based on the torsion
pendulum or torsion balance scheme as in the experiment by Cavendish in 1798,
and in all cases macroscopic masses were used. Here we report the precise
determination of G using laser-cooled atoms and quantum interferometry. We
obtain the value G=6.67191(99) x 10^(-11) m^3 kg^(-1) s^(-2) with a relative
uncertainty of 150 parts per million (the combined standard uncertainty is
given in parentheses). Our value differs by 1.5 combined standard deviations
from the current recommended value of the Committee on Data for Science and
Technology. A conceptually different experiment such as ours helps to identify
the systematic errors that have proved elusive in previous experiments, thus
improving the confidence in the value of G. There is no definitive relationship
between G and the other fundamental constants, and there is no theoretical
prediction for its value, against which to test experimental results. Improving
the precision with which we know G has not only a pure metrological interest,
but is also important because of the key role that G has in theories of
gravitation, cosmology, particle physics and astrophysics and in geophysical
models.Comment: 3 figures, 1 tabl
Using fractional exhaled nitric oxide (FeNO) to diagnose steroid-responsive disease and guide asthma management in routine care
Acknowledgements We thank Robin Taylor for his informative thinking and publications on FeNO, which have helped to influence and direct the thinking of the authors. Funding Extraction of the real-life dataset was funded by Research in Real Life Limited, the analysis of the dataset and the writing of this manuscript were co-funded (50:50) by Research in Real Life Limited and Aerocrine.Peer reviewedPublisher PD
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