arXiv subjects

Tomokazu Fukuda

Publications and source records attributed to Tomokazu Fukuda.

4 recordsLinked to original sources

arXiv2024

Method of Tracking and Analysis of Fluorescent-Labeled Cells Using Automatic Thresholding and Labeling

High-throughput screening using cell images is an efficient method for screening new candidates for pharmaceutical drugs. To complete the screening process, it is essential to have an efficient process for analyzing cell images. This paper presents a new method for efficiently tracking cells and quantitatively detecting the signal ratio between cytoplasm and nuclei. Existing methods include those that use image processing techniques and those that utilize artificial intelligence (AI). However, these methods do not consider the correspondence of cells between images, or require a significant amount of new learning data to train AI. Therefore, our method uses automatic thresholding and labeling algorithms to compare the position of each cell between images, and continuously measure and analyze the signal ratio of cells. This paper describes the algorithm of our method. Using the method, we experimented to investigate the effect of the number of opening and closing operations during the binarization process on the tracking of the cells. Through the experiment, we determined the appropriate number of opening and closing processes.

cs.CV↗

arXiv2017

Search for Tetraneutron by Pion Double Charge Exchange Reaction at J-PARC

Tetraneutron ($^4n$) has come back in the limelight, because of recent observation of a candidate resonant state at RIBF. We propose to investigate the pion double charge exchange (DCX) reaction, i.e. $^4\mathrm{He}(π^- , π^+)$, as an alternative way to populate tetraneutron. An intense $π^-$ beam with the kinetic energy of ~850 MeV, much higher than that in past experiments at LAMPF and TRIUMF, will open up a possibility to improve the experimental sensitivity of the formation cross section, which will be much smaller than hitherto known DCX cross sections such as $^9\mathrm{Be}(π^-, π^+)^9\mathrm{He}\ (g.s.)$.

nucl-ex↗

arXiv2015

Search for the deeply bound $K^-pp$ state from the semi-inclusive forward-neutron spectrum in the in-flight $K^-$ reaction on helium-3

An experiment to search for the $K^-pp$ bound state was performed via the in-flight $^3$He($K^-,n)$ reaction using 5.3 $\times$ $10^9$ kaons at 1 GeV/$c$ at the J-PARC hadron experimental facility. In the semi-inclusive neutron missing-mass spectrum at $θ_{n}^{lab}=0^\circ$, no significant peak was observed in the region corresponding to $K^-pp$ binding energy larger than 80 MeV, where a bump structure has been reported in the $Λp$ final state in different reactions. Assuming the state to be isotropically decaying into $Λp$, mass-dependent upper limits on the production cross section were determined to be 30--180, 70--250, and 100--270 $μ$b/sr, for the natural widths of 20, 60, and 100 MeV, respectively, at 95\% confidence level.

nucl-ex↗

arXiv2012

The K1.8BR spectrometer system at J-PARC

A new spectrometer system was designed and constructed at the secondary beam line K1.8BR in the hadron hall of J-PARC to investigate $\bar K N$ interactions and $\bar K$-nuclear bound systems. The spectrometer consists of a high precision beam line spectrometer, a liquid $^3$He/$^4$He/D$_2$ target system, a Cylindrical Detector System that surrounds the target to detect the decay particles from the target region, and a neutron time-of-flight counter array located $\sim$15 m downstream from the target position. Details of the design, construction, and performance of the detector components are described.

physics.ins-det↗