40 research outputs found
Multiple emission lines of H emitters at from the broad and medium-band photometry in the ZFOURGE Survey
We present a multiple emission lines study of 1300 H emitters
(HAEs) at in the ZFOURGE survey. In contrast to the traditional
spectroscopic method, our sample is selected based on the flux excess in the
ZFOURGE- broad-band data relative to the best-fit stellar continuum. Using
the same method, we also extract the strong diagnostic emission lines for these
individual HAEs: [OIII],
[OII]. Our measurements exhibit good consistency with
those obtained from spectroscopic surveys. We investigate the relationship
between the equivalent widths (EWs) of these emission lines and various galaxy
properties, including stellar mass, stellar age, star formation rate (SFR),
specific SFR (sSFR), ionization states (O32). We have identified a discrepancy
between between HAEs at and typical local star-forming galaxy
observed in the SDSS, suggesting the evolution of lower gas-phase metallicity
() and higher ionization parameters () with redshift. Notably, we have
observed a significant number of low-mass HAEs exhibiting exceptionally high
. Their galaxy properties are comparable to those of
extreme objects, such as extreme O3 emitters (O3Es) and Ly emitters
(LAEs) at . Considering that these characteristics may indicate
potential strong Lyman continuum (LyC) leakage, higher redshift anaglogs of the
low-mass HAEs could be significant contributors to the cosmic reionization.
Further investigations on this particular population are required to gain a
clearer understanding of galaxy evolution and cosmic reionization.Comment: 24 pages, 13 figures, submitted to Ap
Environmental impact on star-forming galaxies in a cluster during course of galaxy accretion
Galaxies change their properties as they assemble into clusters. In order to
understand the physics behind that, we need to go back in time and observe
directly what is occurring in galaxies as they fall into a cluster. We have
conducted a narrow-band and -band imaging survey on a cluster CL1604-D at
using a new infrared instrument SWIMS installed at the Subaru
Telescope. The narrow-band filter, NB1261, matches to H emission from
the cluster at . Combined with a wide range of existing data from
various surveys, we have investigated galaxy properties in and around this
cluster in great detail. We have identified 27 H emitters associated
with the cluster. They have significant overlap with MIPS 24m sources and
are located exclusively in the star forming regime on the rest-frame
diagram. We have identified two groups of galaxies near the cluster in the 2D
spatial distribution and the phase-space diagram, which are likely to be
in-falling to the cluster main body. We have compared various physical
properties of star forming galaxies, such as specific star formation rates
(burstiness) and morphologies (merger) as a function of environment; cluster
center, older group, younger group, and the field. As a result, a global
picture has emerged on how the galaxy properties are altered as they assemble
into a denser region. This includes the occurrence of mergers, enhancement of
star formation activity, excursion to the dusty starburst phase, and eventual
quenching to a passive phase.Comment: 19 pages, 15 figures. Accepted for publication in ApJ. Error bars in
Table 2 correcte
Fabrication of Functionalized Double-Lamellar Multifunctional Envelope-Type Nanodevices Using a Microfluidic Chip with a Chaotic Mixer Array
Multifunctional envelope-type nanodevices (MENDs) are very promising non-viral gene delivery vectors because they are biocompatible and enable programmed packaging of various functional elements into an individual nanostructured liposome. Conventionally MENDs have been fabricated by complicated, labor-intensive, time-consuming bulk batch methods. To avoid these problems in MEND fabrication, we adopted a microfluidic chip with a chaotic mixer array on the floor of its reaction channel. The array was composed of 69 cycles of the staggered chaotic mixer with bas-relief structures. Although the reaction channel had very large Péclet numbers (>105) favorable for laminar flows, its chaotic mixer array led to very small mixing lengths (<1.5 cm) and that allowed homogeneous mixing of MEND precursors in a short time. Using the microfluidic chip, we fabricated a double-lamellar MEND (D-MEND) composed of a condensed plasmid DNA core and a lipid bilayer membrane envelope as well as the D-MEND modified with trans-membrane peptide octaarginine. Our lab-on-a-chip approach was much simpler, faster, and more convenient for fabricating the MENDs, as compared with the conventional bulk batch approaches. Further, the physical properties of the on-chip-fabricated MENDs were comparable to or better than those of the bulk batch-fabricated MENDs. Our fabrication strategy using microfluidic chips with short mixing length reaction channels may provide practical ways for constructing more elegant liposome-based non-viral vectors that can effectively penetrate all membranes in cells and lead to high gene transfection efficiency
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target