4,044 research outputs found
Morphology of Galaxies in JWST Fields: Initial Distribution and Evolution of Galaxy Morphology
A recent study from the Horizon Run (HR5) cosmological simulation has
predicted that galaxies with in the
cosmic morning () dominantly have disk-like morphology in
the CDM universe, which is driven by the tidal torque in the initial
matter fluctuations. For a direct comparison with observation, we identify a
total of about James Webb Space Telescope (JWST) galaxies with at utilizing deep JWST/NIRCam images of
publicly released fields, including NEP-TDF, NGDEEP, CEERS, COSMOS, UDS, and
SMACS J07237327. We estimate their stellar masses and photometric redshifts
with the redshift dispersion of and outlier fraction
of only about . We classify galaxies into three morphological types,
`disks', `spheroids', and `irregulars', applying the same criteria used in the
HR5 study. The morphological distribution of the JWST galaxies shows that disk
galaxies account for at all redshift ranges. However, in the
high-mass regime (), spheroidal
morphology becomes the dominant type. This implies that mass growth of galaxies
is accompanied with morphological transition from disks to spheroids. The
fraction of irregulars is about 20\% or less at all mass and redshifts. All the
trends in the morphology distribution are consistently found in the six JWST
fields. These results are in close agreement with the results from the HR5
simulation, particularly confirming the prevalence of disk galaxies at small
masses in the cosmic morning and noon.Comment: Accepted for publication in ApJ, 30 pages, 14 figures, 5 tables, 3
appendice
Downregulation of protein kinase CK2 activity induces age-related biomarkers in C. elegans
Studies show that a decrease in protein kinase CK2 (CK2) activity is associated with cellular senescence. However, the role of CK2 in organism aging is still poorly understood. Here, we investigated whether protein kinase CK2 (CK2) modulated longevity in Caenorhabditis elegans. CK2 activity decreased with advancing age in the worms. Knockdown of kin-10 (the ortholog of CK2 beta) led to a short lifespan phenotype and induced age-related biomarkers, including retardation of locomotion, decreased pharyngeal pumping rate, increased lipofuscin accumulation, and reduced resistance to heat and oxidative stress. The long lifespan of age-1 and akt-1 mutants was significantly suppressed by kin-10 RNAi, suggesting that CK2 acts downstream of AGE-1 and AKT-1. Kin-10 knockdown did not further shorten the short lifespan of daf-16 mutant worms but either decreased or increased the transcriptional activity of DAF-16 depending on the promoters of the target genes, indicating that CK2 is an upstream regulator of DAF-16 in C. elegans. Kin-10 knockdown increased production of reactive oxygen species (ROS) in the worms. Finally, the ROS scavenger N-acetyl-L-cysteine significantly counteracts the lifespan shortening and lipofuscin accumulation induced by kin-10 knockdown. Therefore, the present results suggest that age-dependent CK2 downregulation reduces longevity by associating with both ROS generation and the AGE-1-AKT-1-DAF-16 pathway in C. elegans. © Copyright 2017 Elsevier B.V., All rights reserved.1111sci
Warm Surprises from Cold Duets: N-Body Simulations with Two-Component Dark Matter
We explore extensive N-body simulations with two-component cold dark matter
candidates. We delve into the temperature evolution, power spectrum, density
perturbation, and maximum circular velocity functions. We find that the
substantial mass difference between the two candidates and the annihilation of
the heavier components to the lighter ones effectively endow the latter with
warm dark matter-like behavior, taking advantage of all distinct features that
warm dark matter candidates offer, without observational bounds on the warm
dark matter mass. Moreover, we demonstrate that the two-component dark matter
model aligns well with observational data, providing valuable insights into
where and how to search for the elusive dark matter candidates in terrestrial
experiments.Comment: 7 pages, 5 figure
Nanoscale reaction vessels: Highly ordered nanocrystal arrays inside porous anodic alumina nanowells
Using an anodic alumina template as a nanoscale reaction vessel, the authors developed a simple and unique method to prepare highly ordered arrays of nanocrystals in isolated nanowells. The highly ordered arrays of nanoscale wells were fabricated by short anodization. After the nanoscale wells were filled with a precursor solution of NaCl by dewetting, the solvent of the precursor solution was evaporated, resulting in spontaneous formation of uniformly sized NaCl nanocrystals inside the nanoscale wells. The size of crystals could be easily adjusted by varying the concentration of the precursor solution and the size of nanoscale wells. This approach is simple and cost-effective, and it can fabricate nanocrystal arrays on substrates with high throughput. It can also be readily adapted to synthesize other types of high-density nanocrystal arrays on different substrates. © 2015 The Authorsopen0
Three-way Translocation of MLL/MLLT3, t(1;9;11)(p34.2;p22;q23), in a Pediatric Case of Acute Myeloid Leukemia
The chromosome band 11q23 is a common target region of chromosomal translocation in different types of leukemia, including infantile leukemia and therapy-related leukemia. The target gene at 11q23, MLL, is disrupted by the translocation and becomes fused to various translocation partners. We report a case of AML with a rare 3-way translocation involving chromosomes 1, 9, and 11: t(1;9;11)(p34.2;p22;q23). A 3-yr-old Korean girl presented with a 5-day history of fever. A diagnosis of AML was made on the basis of the morphological evaluation and immunophenotyping of bone marrow specimens. Flow cytometric immunophenotyping showed blasts positive for myeloid lineage markers and aberrant CD19 expression. Karyotypic analysis showed 46,XX,t(1;9;11)(p34.2;p22;q23) in 19 of the 20 cells analyzed. This abnormality was involved in MLL/MLLT3 rearrangement, which was confirmed by qualitative multiplex reverse transcription-PCR and interphase FISH. She achieved morphological and cytogenetic remission after 1 month of chemotherapy and remained event-free for 6 months. Four cases of t(1;9;11)(v;p22;q23) have been reported previously in a series that included cases with other 11q23 abnormalities, making it difficult to determine the distinctive clinical features associated with this abnormality. To our knowledge, this is the first description of t(1;9;11) with clinical and laboratory data, including the data for the involved genes, MLL/MLLT3
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