88 research outputs found
Localization of massive fermions on the baby-skyrmion branes in 6 dimensions
We construct brane solutions in 6 dimensional Einstein-Skyrme systems. A
class of baby skyrmion solutions realizes warped compactification of the extra
dimensions and gravity localization on the brane for negative bulk cosmological
constant. Coupling of the fermions with the brane skyrmions lead to the brane
localized fermions. In terms of the level crossing picture, emergence of the
massive localized modes as well as the zero mode are observed. Nonlinear nature
of the skyrmions brings richer information for the fermions level structure.
The level comprises doubly degenerate lowest plus single excited modes. The
three generation of the fundamental fermions is based on this structure. The
quark/lepton mass hierarchy is successfully obtained in terms of a slightly
deformed baby-skyrmions with topological charge three.Comment: 16 pages, 17 figures. One figure added, some points clarified,
references improved. Version accepted for publicatio
Organellar Glue: A Molecular Tool to Artificially Control Chloroplast–Chloroplast Interactions
細胞小器官を接着する新技術「オルガネラグルー」を開発 --オルガネラ間コミュニケーションの操作に期待--. 京都大学プレスリリース. 2022-09-30.Organelles can physically interact to facilitate various cellular processes such as metabolite exchange. Artificially regulating these interactions represents a promising approach for synthetic biology. Here, we artificially controlled chloroplast–chloroplast interactions in living plant cells with our organelle glue (ORGL) technique, which is based on reconstitution of a split fluorescent protein. We simultaneously targeted N-terminal and C-terminal fragments of a fluorescent protein to the chloroplast outer envelope membrane or cytosol, respectively, which induced chloroplast–chloroplast interactions. The cytosolic C-terminal fragment likely functions as a bridge between two N-terminal fragments, thereby bringing the chloroplasts in close proximity to interact. We modulated the frequency of chloroplast–chloroplast interactions by altering the ratio of N- and C-terminal fragments. We conclude that the ORGL technique can successfully control chloroplast–chloroplast interactions in plants, providing a proof of concept for the artificial regulation of organelle interactions in living cells
Obliquity of an Earth-like planet from frequency modulation of its direct imaged lightcurve: mock analysis from general circulation model simulation
Direct-imaging techniques of exoplanets have made significant progress
recently, and will eventually enable to monitor photometric and spectroscopic
signals of earth-like habitable planets in the future. The presence of clouds,
however, would remain as one of the most uncertain components in deciphering
such direct-imaged signals of planets. We attempt to examine how the planetary
obliquity produce different cloud patterns by performing a series of GCM
(General Circulation Model) simulation runs using a set of parameters relevant
for our Earth. Then we use the simulated photometric lightcurves to compute
their frequency modulation due to the planetary spin-orbit coupling over an
entire orbital period, and attempt to see to what extent one can estimate the
obliquity of an Earth-twin. We find that it is possible to estimate the
obliquity of an Earth-twin within the uncertainty of several degrees with a
dedicated 4 m space telescope at 10 pc away from the system if the stellar flux
is completely blocked. While our conclusion is based on several idealized
assumptions, a frequency modulation of a directly-imaged earth-like planet
offers a unique methodology to determine its obliquity.Comment: 29 pages, 18 figures, accepted for publication in Ap
Single-shot laser-driven neutron resonance spectroscopy for temperature profiling
Lan Z., Arikawa Y., Mirfayzi S.R., et al. Single-shot laser-driven neutron resonance spectroscopy for temperature profiling. Nature Communications 15, 5365 (2024); https://doi.org/10.1038/s41467-024-49142-y.The temperature measurement of material inside of an object is one of the key technologies for control of dynamical processes. For this purpose, various techniques such as laser-based thermography and phase-contrast imaging thermography have been studied. However, it is, in principle, impossible to measure the temperature of an element inside of an object using these techniques. One of the possible solutions is measurements of Doppler brooding effect in neutron resonance absorption (NRA). Here we present a method to measure the temperature of an element or an isotope inside of an object using NRA with a single neutron pulse of approximately 100 ns width provided from a high-power laser. We demonstrate temperature measurements of a tantalum (Ta) metallic foil heated from the room temperature up to 617 K. Although the neutron energy resolution is fluctuated from shot to shot, we obtain the temperature dependence of resonance Doppler broadening using a reference of a silver (Ag) foil kept to the room temperature. A free gas model well reproduces the results. This method enables element(isotope)-sensitive thermometry to detect the instantaneous temperature rise in dynamical processes
Localizing gravity on Maxwell gauged CP1 model in six dimensions
We shall consider about a 3-brane embedded in six-dimensional space-time with
a negative bulk cosmological constant. The 3-brane is constructed by a
topological soliton solution living in two-dimensional axially symmetric
transverse subspace. Similar to most previous works of six-dimensional soliton
models, our Maxwell gauged CP1 brane model can also achieve to localize gravity
around the 3-brane. The CP1 field is described by a scalar doublet and derived
from O(3) sigma model by projecting it onto two-dimensional complex space. In
that sense, our framework is more effective than other solitonic brane models
concerning with gauge theory. We shall also discuss about linear stability
analysis for our new model by fluctuating all fields.Comment: 23 pages, 7 figures; references adde
Serum growth differentiation factor 15 is a novel biomarker with high predictive capability for liver cancer occurrence in patients with MASLD regardless of liver fibrosis
Kumazaki S., Hikita H., Tahata Y., et al. Serum growth differentiation factor 15 is a novel biomarker with high predictive capability for liver cancer occurrence in patients with MASLD regardless of liver fibrosis. Alimentary Pharmacology and Therapeutics , (2024); https://doi.org/10.1111/apt.18063.Background and Aims: Although metabolic dysfunction-associated steatotic liver disease (MASLD) patients with a Fib-4 index >1.3 are recommended for fibrosis evaluation via elastography or biopsy, a more convenient method identifying high-risk populations requiring follow-up is needed. We explored the utility of serum levels of growth differentiation factor-15 (GDF15), a cell stress-responsive cytokine related to metabolic syndrome, for stratifying the risk of clinical events in MASLD patients. Methods: Serum GDF15 levels were measured in 518 biopsy-performed MASLD patients, 216 MASLD patients for validation, and 361 health checkup recipients with MASLD. Results: In the biopsy-MASLD cohort, multivariate analysis indicated that the serum GDF15 level was a risk factor for liver cancer, independent of the fibrosis stage or Fib-4 index. Using a GDF15 cutoff of 1.75 ng/mL based on the Youden index, high-GDF15 patients, regardless of fibrosis status, had a higher liver cancer incidence rate. While patients with a Fib-4 index 1.3 developed liver cancer and decompensated liver events at significantly higher rates and had poorer prognoses. In the validation cohort, high-GDF15 patients had significantly higher incidences of liver cancer and decompensated liver events and poorer prognoses than low-GDF15 patients, whether limited to high-Fib-4 patients. Among health checkup recipients with MASLD, 23.0% had a Fib-4 index >1.3, 2.7% had a Fib-4 index >1.3 and >1.75 ng/mL GDF15. Conclusions: Serum GDF15 is a biomarker for liver cancer with high predictive capability and is useful for identifying MASLD patients requiring regular surveillance
Five doses of the mRNA vaccination potentially suppress ancestral-strain stimulated SARS-CoV2-specific cellular immunity: a cohort study from the Fukushima vaccination community survey, Japan
The bivalent mRNA vaccine is recommended to address coronavirus disease variants, with additional doses suggested for high-risk groups. However, the effectiveness, optimal frequency, and number of doses remain uncertain. In this study, we examined the long-term cellular and humoral immune responses following the fifth administration of the mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine in patients undergoing hemodialysis. To our knowledge, this is the first study to monitor long-term data on humoral and cellular immunity dynamics in high-risk populations after five doses of mRNA vaccination, including the bivalent mRNA vaccine. Whereas most patients maintained humoral immunity throughout the observation period, we observed reduced cellular immune reactivity as measured by the ancestral-strain-stimulated ELISpot assay in a subset of patients. Half of the individuals (50%; 14/28) maintained cellular immunity three months after the fifth dose, despite acquiring humoral immunity. The absence of a relationship between positive controls and T-Spot reactivity suggests that these immune alterations were specific to SARS-CoV-2. In multivariable analysis, participants aged ≥70 years showed a marginally significant lower likelihood of having reactive results. Notably, among the 14 individuals who received heterologous vaccines, 13 successfully acquired cellular immunity, supporting the effectiveness of this administration strategy. These findings provide valuable insights for future vaccination strategies in vulnerable populations. However, further research is needed to evaluate the involvement of immune tolerance and exhaustion through repeated vaccination to optimize immunization strategies
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