42 research outputs found
Ultracold Atoms as a Target: Absolute Scattering Cross-Section Measurements
We report on a new experimental platform for the measurement of absolute
scattering cross-sections. The target atoms are trapped in an optical dipole
trap and are exposed to an incident particle beam. The exponential decay of the
atom number directly yields the absolute total scattering cross-section. The
technique can be applied to any atomic or molecular species that can be
prepared in an optical dipole trap and provides a large variety of possible
scattering scenarios
A Scanning Electron Microscope for Ultracold Atoms
We propose a new technique for the detection of single atoms in ultracold
quantum gases. The technique is based on scanning electron microscopy and
employs the electron impact ionization of trapped atoms with a focussed
electron probe. Subsequent detection of the resulting ions allows for the
reconstruction of the atoms position. This technique is expected to achieve a
much better spatial resolution compared to any optical detection method. In
combination with the sensitivity to single atoms, it makes new in situ
measurements of atomic correlations possible. The detection principle is also
well suited for the addressing of individual sites in optical lattices.Comment: 5 pages, 2 figure
Markov Properties of Electrical Discharge Current Fluctuations in Plasma
Using the Markovian method, we study the stochastic nature of electrical
discharge current fluctuations in the Helium plasma. Sinusoidal trends are
extracted from the data set by the Fourier-Detrended Fluctuation analysis and
consequently cleaned data is retrieved. We determine the Markov time scale of
the detrended data set by using likelihood analysis. We also estimate the
Kramers-Moyal's coefficients of the discharge current fluctuations and derive
the corresponding Fokker-Planck equation. In addition, the obtained Langevin
equation enables us to reconstruct discharge time series with similar
statistical properties compared with the observed in the experiment. We also
provide an exact decomposition of temporal correlation function by using
Kramers-Moyal's coefficients. We show that for the stationary time series, the
two point temporal correlation function has an exponential decaying behavior
with a characteristic correlation time scale. Our results confirm that, there
is no definite relation between correlation and Markov time scales. However
both of them behave as monotonic increasing function of discharge current
intensity. Finally to complete our analysis, the multifractal behavior of
reconstructed time series using its Keramers-Moyal's coefficients and original
data set are investigated. Extended self similarity analysis demonstrates that
fluctuations in our experimental setup deviates from Kolmogorov (K41) theory
for fully developed turbulence regime.Comment: 25 pages, 9 figures and 4 tables. V3: Added comments, references,
figures and major correction
T-BET and EOMES sustain mature human NK cell identity and antitumor function
Since the T-box transcription factors (TFs) T-BET and EOMES are necessary for initiation of NK cell development, their ongoing requirement for mature NK cell homeostasis, function, and molecular programming remains unclear. To address this, T-BET and EOMES were deleted in unexpanded primary human NK cells using CRISPR/Cas9. Deleting these TFs compromised in vivo antitumor response of human NK cells. Mechanistically, T-BET and EOMES were required for normal NK cell proliferation and persistence in vivo. NK cells lacking T-BET and EOMES also exhibited defective responses to cytokine stimulation. Single-cell RNA-Seq revealed a specific T-box transcriptional program in human NK cells, which was rapidly lost following T-BET and EOMES deletion. Further, T-BET- and EOMES-deleted CD56bright NK cells acquired an innate lymphoid cell precursor-like (ILCP-like) profile with increased expression of the ILC-3-associated TFs RORC and AHR, revealing a role for T-box TFs in maintaining mature NK cell phenotypes and an unexpected role of suppressing alternative ILC lineages. Our study reveals the critical importance of sustained EOMES and T-BET expression to orchestrate mature NK cell function and identity
Adipose and muscle tissue profile of CD36 transcripts in obese subjects highlights the role of CD36 in fatty acid homeostasis and insulin resistance
Fatty acid (FA) metabolism is tightly regulated across several tissues and impacts insulin sensitivity. CD36 facilitates cellular FA uptake, and CD36 genetic variants associate with lipid abnormalities and susceptibility to metabolic syndrome. The objective of this study was to gain insight regarding the in vivo metabolic influence of muscle and adipose tissue CD36. For this, we determined the relationships between CD36 alternative transcripts, which can reflect tissue-specific CD36 regulation, and measures of FA metabolism and insulin resistance
Cytokine-induced memory-like natural killer cells exhibit enhanced responses against myeloid leukemia
Transplantation and autoimmunit