2,667 research outputs found
Scaffolding with video prior to sophomore physics lab: The addition and resolution of vectors
Technical note: colab_zirc_dims: a Google Colab-compatible toolset for automated and semi-automated measurement of mineral grains in laser ablation–inductively coupled plasma–mass spectrometry images using deep learning models
Collecting grain measurements for large detrital zircon age datasets is a
time-consuming task, but a growing number of studies suggest such data are
essential to understanding the complex roles of grain size and morphology in
grain transport and as indicators for grain provenance. We developed the
colab_zirc_dims Python package to automate
deep-learning-based segmentation and measurement of mineral grains from
scaled images captured during laser ablation at facilities that use Chromium
targeting software. The colab_zirc_dims
package is implemented in a collection of highly interactive Jupyter
notebooks that can be run either on a local computer or installation-free
via Google Colab. These notebooks also provide additional functionalities
for dataset preparation and for semi-automated grain segmentation and
measurement using a simple graphical user interface. Our automated grain
measurement algorithm approaches human measurement accuracy when applied to
a manually measured n=5004 detrital zircon dataset. Errors and
uncertainty related to variable grain exposure necessitate semi-automated
measurement for production of publication-quality measurements, but we
estimate that our semi-automated grain segmentation workflow will enable
users to collect grain measurement datasets for large (n≥5000)
applicable image datasets in under a day of work. We hope that the
colab_zirc_dims toolset allows more
researchers to augment their detrital geochronology datasets with grain
measurements.</p
Search for {\eta}'(958)-nucleus bound states by (p,d) reaction at GSI and FAIR
The mass of the {\eta}' meson is theoretically expected to be reduced at
finite density, which indicates the existence of {\eta}'-nucleus bound states.
To investigate these states, we perform missing-mass spectroscopy for the (p,
d) reaction near the {\eta}' production threshold. The overview of the
experimental situation is given and the current status is discussed.Comment: 6 pages, 3 figures; talk at II Symposium on applied nuclear physics
and innovative technologies, September 24th - 27th, 2014, Jagiellonian
University, Krak\'ow Poland; to appear in Acta Physica Polonica
\b{eta}-delayed three-proton decay of 31Ar
The beta decay of 31Ar, produced by fragmentation of a 36Ar beam at 880
MeV/nucleon, was investigated. Identified ions of 31Ar were stopped in a
gaseous time projection chamber with optical readout allowing to record decay
events with emission of protons. In addition to \b{eta}-delayed emission of one
and two protons we have clearly observed the beta-delayed three-proton branch.
The branching ratio for this channel in 31Ar is found to be 0.07(2)%.Comment: 5 pages, 3 figures, submitted to Physical Rev.
Spermidine/Spermine N1-Acetyltransferase 1 (SAT1)—A Potential Gene Target for Selective Sensitization of Glioblastoma Cells Using an Ionizable Lipid Nanoparticle to Deliver siRNA
Spermidine/spermine N1-acetyltransferase 1 (SAT1) responsible for cell polyamine catabolism is overexpressed in glioblastoma multiforme (GB). Its role in tumor survival and promoting resistance towards radiation therapy has made it an interesting target for therapy. In this study, we prepared a lipid nanoparticle-based siRNA delivery system (LNP-siSAT1) to selectively knockdown (KD) SAT1 enzyme in a human glioblastoma cell line. The LNP-siSAT1 containing ionizable DODAP lipid was prepared following a microfluidics mixing method and the resulting nanoparticles had a hydrodynamic size of around 80 nm and a neutral surface charge. The LNP-siSAT1 effectively knocked down the SAT1 expression in U251, LN229, and 42MGBA GB cells, and other brain-relevant endothelial (hCMEC/D3), astrocyte (HA) and macrophage (ANA-1) cells at the mRNA and protein levels. SAT1 KD in U251 cells resulted in a 40% loss in cell viability. Furthermore, SAT1 KD in U251, LN229 and 42MGBA cells sensitized them towards radiation and chemotherapy treatments. In contrast, despite similar SAT1 KD in other brain-relevant cells no significant effect on cytotoxic response, either alone or in combination, was observed. A major roadblock for brain therapeutics is their ability to cross the highly restrictive blood–brain barrier (BBB) presented by the brain microcapillary endothelial cells. Here, we used the BBB circumventing approach to enhance the delivery of LNP-siSAT1 across a BBB cell culture model. A cadherin binding peptide (ADTC5) was used to transiently open the BBB tight junctions to promote paracellular diffusion of LNP-siSAT1. These results suggest LNP-siSAT1 may provide a safe and effective method for reducing SAT1 and sensitizing GB cells to radiation and chemotherapeutic agents
Spectroscopy of -nucleus bound states at GSI and FAIR --- very preliminary results and future prospects ---
The possible existence of \eta'-nucleus bound states has been put forward
through theoretical and experimental studies. It is strongly related to the
\eta' mass at finite density, which is expected to be reduced because of the
interplay between the anomaly and partial restoration of chiral
symmetry. The investigation of the C(p,d) reaction at GSI and FAIR, as well as
an overview of the experimental program at GSI and future plans at FAIR are
discussed.Comment: 7 pages, 3 figures; talk at the International Conference on Exotic
Atoms and Related Topics (EXA2014), Vienna, Austria, 15-19 September 2014. in
Hyperfine Interactions (2015
Discovery and Cross-Section Measurement of Neutron-Rich Isotopes in the Element Range from Neodymium to Platinum at the FRS
With a new detector setup and the high-resolution performance of the fragment
separator FRS at GSI we discovered 57 new isotopes in the atomic number range
of 60: \nuc{159-161}{Nb}, \nuc{160-163}{Pm}, \nuc{163-166}Sm,
\nuc{167-168}{Eu}, \nuc{167-171}{Gd}, \nuc{169-171}{Tb}, \nuc{171-174}{Dy},
\nuc{173-176}{Ho}, \nuc{176-178}{Er}, \nuc{178-181}{Tm}, \nuc{183-185}{Yb},
\nuc{187-188}{Lu}, \nuc{191}{Hf}, \nuc{193-194}{Ta}, \nuc{196-197}{W},
\nuc{199-200}{Re}, \nuc{201-203}{Os}, \nuc{204-205}{Ir} and \nuc{206-209}{Pt}.
The new isotopes have been unambiguously identified in reactions with a
U beam impinging on a Be target at 1 GeV/u. The isotopic production
cross-section for the new isotopes have been measured and compared with
predictions of different model calculations. In general, the ABRABLA and COFRA
models agree better than a factor of two with the new data, whereas the
semiempirical EPAX model deviates much more. Projectile fragmentation is the
dominant reaction creating the new isotopes, whereas fission contributes
significantly only up to about the element holmium.Comment: 9 pages, 4 figure
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