188 research outputs found
Reversible low-light induced photoswitching of crowned spiropyran-DO3A complexed with gadolinium(III) ions.
Photoswitchable spiropyran has been conjugated to the crowned ring system DO3A, which improves its solubility in dipolar and polar media and stabilizes the merocyanine isomer. Adding the lanthanide ion gadolinium(III) to the macrocyclic ring system leads to a photoresponsive magnetic resonance imaging contrast agent that displays an increased spin-lattice relaxation time (T₁) upon visible light stimulation. In this work, the photoresponse of this photochromic molecule to weak light illumination using blue and green light emitting diodes was investigated, simulating the emission spectra from bioluminescent enzymes. Photon emission rate of the light emitting diodes was changed, from 1.75 × 10¹⁶ photons·s⁻¹ to 2.37 × 10¹² photons·s⁻¹. We observed a consistent visible light-induced isomerization of the merocyanine to the spiropyran form with photon fluxes as low as 2.37 × 10¹² photons·s⁻¹ resulting in a relaxivity change of the compound. This demonstrates the potential for use of the described imaging probes in low light level applications such as sensing bioluminescence enzyme activity. The isomerization behavior of gadolinium(III)-ion complexed and non-complexed spiropyran-DO3A was analyzed in water and ethanol solution in response to low light illumination and compared to the emitted photon emission rate from over-expressed Gaussia princeps luciferase
Corrupción y gestión migratoria en el México posrevolucionario
This work studies the nature, extension and significances of the corruption practices inside the Mexican Migration Service during the first decades of the 20th century. In a context in which the need to enter or exit the country was seen, both by Mexicans or foreigners, as an opportunity for illicit enrichment, the article reveals how corruption practices flourished under the increase of immigration regulations. The pervasiveness of these practices allows one to assess them as a consubstantial part of the political order as opposed to an issue of a moral character.En este trabajo se estudia la naturaleza, extensión y significados de prácticas de corrupción en el Servicio de Migración de México durante las primeras décadas del siglo XX. Se advierten las maneras en que la corrupción creció al amparo de un ensanchamiento de las regulaciones migratorias y el control fronterizo, en un contexto en que la necesidad de ingresar o salir de país por parte de extranjeros y mexicanos era valorada como una oportunidad para enriquecimientos ilícitos. La dimensión alcanzada por estas prácticas permite valorarlas como parte consustancial del orden político antes que como un asunto de carácter moral
Targeting and killing of glioblastoma with activated T cells armed with bispecific antibodies
Abstract
Background
Since most glioblastomas express both wild-type EGFR and EGFRvIII as well as HER2/neu, they are excellent targets for activated T cells (ATC) armed with bispecific antibodies (BiAbs) that target EGFR and HER2.
Methods
ATC were generated from PBMC activated for 14 days with anti-CD3 monoclonal antibody in the presence of interleukin-2 and armed with chemically heteroconjugated anti-CD3×anti-HER2/neu (HER2Bi) and/or anti-CD3×anti-EGFR (EGFRBi). HER2Bi- and/or EGFRBi-armed ATC were examined for in vitro cytotoxicity using MTT and 51Cr-release assays against malignant glioma lines (U87MG, U118MG, and U251MG) and primary glioblastoma lines.
Results
EGFRBi-armed ATC killed up to 85% of U87, U118, and U251 targets at effector:target ratios (E:T) ranging from 1:1 to 25:1. Engagement of tumor by EGFRBi-armed ATC induced Th1 and Th2 cytokine secretion by armed ATC. HER2Bi-armed ATC exhibited comparable cytotoxicity against U118 and U251, but did not kill HER2-negative U87 cells. HER2Bi- or EGFRBi-armed ATC exhibited 50—80% cytotoxicity against four primary glioblastoma lines as well as a temozolomide (TMZ)-resistant variant of U251. Both CD133– and CD133+ subpopulations were killed by armed ATC. Targeting both HER2Bi and EGFRBi simultaneously showed enhanced efficacy than arming with a single BiAb. Armed ATC maintained effectiveness after irradiation and in the presence of TMZ at a therapeutic concentration and were capable of killing multiple targets.
Conclusion
High-grade gliomas are suitable for specific targeting by armed ATC. These data, together with additional animal studies, may provide the preclinical support for the use of armed ATC as a valuable addition to current treatment regimens
Search for Cosmic-ray Boosted Sub-GeV Dark Matter using Recoil Protons at Super-Kamiokande
We report a search for cosmic-ray boosted dark matter with protons using the
0.37 megatonyears data collected at Super-Kamiokande experiment during
the 1996-2018 period (SKI-IV phase). We searched for an excess of proton
recoils above the atmospheric neutrino background from the vicinity of the
Galactic Center. No such excess is observed, and limits are calculated for two
reference models of dark matter with either a constant interaction
cross-section or through a scalar mediator. This is the first experimental
search for boosted dark matter with hadrons using directional information. The
results present the most stringent limits on cosmic-ray boosted dark matter and
exclude the dark matter-nucleon elastic scattering cross-section between
and for dark matter mass
from 10 MeV/ to 1 GeV/.Comment: With 1-page appendi
Search for Periodic Time Variations of the Solar B Neutrino Flux Between 1996 and 2018 in Super-Kamiokande
We report a search for time variations of the solar B neutrino flux using
5,804 live days of Super-Kamiokande data collected between May 31, 1996, and
May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino
interaction over 22 calendar years to search for solar neutrino flux
modulations with unprecedented precision. Periodic modulations are searched for
in a data set comprised of five-day interval solar neutrino flux measurements
with a maximum likelihood method. We also applied the Lomb-Scargle method to
this data set to compare it with previous reports. The only significant
modulation found is due to the elliptic orbit of the Earth around the Sun. The
observed modulation is consistent with astronomical data: we measured an
eccentricity of (1.530.35)\,\%, and a perihelion shift is
(1.513.5)\,days.Comment: 8 pages, 5 figures, 2 tables, and data file:
"sksolartimevariation5804d.txt
Search for astrophysical electron antineutrinos in Super-Kamiokande with 0.01wt% gadolinium-loaded water
We report the first search result for the flux of astrophysical electron
antineutrinos for energies O(10) MeV in the gadolinium-loaded Super-Kamiokande
(SK) detector. In June 2020, gadolinium was introduced to the ultra-pure water
of the SK detector in order to detect neutrons more efficiently. In this new
experimental phase, SK-Gd, we can search for electron antineutrinos via inverse
beta decay with efficient background rejection and higher signal efficiency
thanks to the high efficiency of the neutron tagging technique. In this paper,
we report the result for the initial stage of SK-Gd with a exposure at 0.01% Gd mass concentration. No significant excess
over the expected background in the observed events is found for the neutrino
energies below 31.3 MeV. Thus, the flux upper limits are placed at the 90%
confidence level. The limits and sensitivities are already comparable with the
previous SK result with pure-water () owing
to the enhanced neutron tagging
Measurement of the cosmogenic neutron yield in Super-Kamiokande with gadolinium loaded water
Cosmic-ray muons that enter the Super-Kamiokande detector cause hadronic
showers due to spallation in water, producing neutrons and radioactive
isotopes. Those are a major background source for studies of MeV-scale
neutrinos and searches for rare events. Since 2020, gadolinium was introduced
in the ultra-pure water in the Super-Kamiokande detector to improve the
detection efficiency of neutrons. In this study, the cosmogenic neutron yield
was measured using data acquired during the period after the gadolinium
loading. The yield was found to be at
259 GeV of average muon energy at the Super-Kamiokande detector.Comment: 10 pages, 10 figures, 3 table
Euclid: The importance of galaxy clustering and weak lensing cross-correlations within the photometric Euclid survey
Context. The data from the Euclid mission will enable the measurement of the angular positions and weak lensing shapes of over a billion galaxies,
with their photometric redshifts obtained together with ground-based observations. This large dataset, with well-controlled systematic effects, will
allow for cosmological analyses using the angular clustering of galaxies (GCph) and cosmic shear (WL). For Euclid, these two cosmological probes
will not be independent because they will probe the same volume of the Universe. The cross-correlation (XC) between these probes can tighten
constraints and is therefore important to quantify their impact for Euclid.
Aims. In this study, we therefore extend the recently published Euclid forecasts by carefully quantifying the impact of XC not only on the
final parameter constraints for different cosmological models, but also on the nuisance parameters. In particular, we aim to decipher the amount
of additional information that XC can provide for parameters encoding systematic effects, such as galaxy bias, intrinsic alignments (IAs), and
knowledge of the redshift distributions.
Methods. We follow the Fisher matrix formalism and make use of previously validated codes. We also investigate a different galaxy bias model,
which was obtained from the Flagship simulation, and additional photometric-redshift uncertainties; we also elucidate the impact of including the
XC terms on constraining these latter.
Results. Starting with a baseline model, we show that the XC terms reduce the uncertainties on galaxy bias by ∼17% and the uncertainties on IA
by a factor of about four. The XC terms also help in constraining the γ parameter for minimal modified gravity models. Concerning galaxy bias,
we observe that the role of the XC terms on the final parameter constraints is qualitatively the same irrespective of the specific galaxy-bias model
used. For IA, we show that the XC terms can help in distinguishing between different models, and that if IA terms are neglected then this can lead
to significant biases on the cosmological parameters. Finally, we show that the XC terms can lead to a better determination of the mean of the
photometric galaxy distributions.
Conclusions. We find that the XC between GCph and WL within the Euclid survey is necessary to extract the full information content from the data
in future analyses. These terms help in better constraining the cosmological model, and also lead to a better understanding of the systematic effects
that contaminate these probes. Furthermore, we find that XC significantly helps in constraining the mean of the photometric-redshift distributions,
but, at the same time, it requires more precise knowledge of this mean with respect to single probes in order not to degrade the final “figure of
merit”
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