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2025
- Book : 63(1)
- Pub. Date : 2025
- Page : pp.1-10
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2025
In animals, mitosis involves the breakdown of the nucleus. The reassembly of a nucleus after mitosis requires the reformation of the nuclear envelope around a single mass of chromosomes. This process requires Ankle2 (also known as LEM4 in humans) which interacts with PP2A and promotes the function of the Barrier-to-Autointegration Factor (BAF). Upon dephosphorylation, BAF dimers cross-bridge chromosomes and bind lamins and transmembrane proteins of the reassembling nuclear envelope. How Ankle2 functions in mitosis is incompletely understood. Using a combination of approaches in Drosophila, along with structural modeling, we provide several lines of evidence that suggest that Ankle2 is a regulatory subunit of PP2A, explaining how it promotes BAF dephosphorylation. In addition, we discovered that Ankle2 interacts with the endoplasmic reticulum protein Vap33, which is required for Ankle2 localization at the reassembling nuclear envelope during telophase. We identified the interaction sites of PP2A and Vap33 on Ankle2. Through genetic rescue experiments, we show that the Ankle2/PP2A interaction is essential for the function of Ankle2 in nuclear reassembly and that the Ankle2/Vap33 interaction also promotes this process. Our study sheds light on the molecular mechanisms of post-mitotic nuclear reassembly and suggests that the endoplasmic reticulum is not merely a source of membranes in the process, but also provides localized enzymatic activity.- Book : 13()
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2025
Neutron-induced reaction cross sections of short-lived nuclei are imperative to understand the origin of heavy elements in stellar nucleosynthesis and for societal applications, but their measurement is extremely complicated due to the radioactivity of the targets involved. One way of overcoming this issue is to combine surrogate reactions with the unique possibilities offered by heavy-ion storage rings. In this work, we describe the first surrogate-reaction experiment in inverse kinematics, which we successfully conducted at the Experimental Storage Ring (ESR) of the GSI/FAIR facility, using the Pb208(p,p′) reaction as a surrogate for neutron capture on Pb207. Thanks to the outstanding detection efficiencies possible at the ESR, we were able to measure for the first time the neutron-emission probability as a function of the excitation energy of Pb208. We have used this probability to select different descriptions of the γ-ray strength function and nuclear level density, and provide reliable results for the neutron-induced radiative capture cross section of Pb207 at energies for which no experimental data exist.
Published by the American Physical Society
2025
- Book : 134(7)
- Pub. Date : 2025
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2025
- Book : ()
- Pub. Date : 2025
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2025
- Book : ()
- Pub. Date : 2025
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2025
Abstract
Progress in physics understanding and theoretical model development of plasma transport and confinement (TC) in the ITPA TC Topical Group since the publication of the ITER Physics Basis (IPB) document (Doyle et al 2007 Nucl. Fusion
47 S18) was summarized focusing on the contributions to ITER and burning plasma prediction and control. This paper provides a general and streamlined overview on the advances that were mainly led by the ITPA TC joint experiments and joint activities for the last 15 years (see JEX/JA table in appendix). This paper starts with the scientific strategy and scope of the ITPA TC Topical group and overall picture of the major progress, followed by the progress of each research field: particle transport, impurity transport, ion and electron thermal turbulent transport, momentum transport, impact of 3D magnetic fields on transport, confinement mode transitions, global confinement, and reduced transport modeling. Cross references with other Topical Groups are given in order to highlight overlapped topics, such as the 3D effect on the plasma transport in the edge and L-H transition physics. The increasing overlap between the topical groups is a reflection of the progress on integrating the known physics into comprehensive models that are better and better able to reproduce the plasma transport. In recent years, such integration has become increasingly prevalent when considering transport from the SOL, through the edge pedestal, and into the plasma core. In the near future, increased collaboration also with the magneto-hydrodynamic and energetic particles community will be important as we approach burning plasma conditions in next-step fusion devices. A summary of remaining challenges and next steps for each research field is given in the Summary section.- Book : 65(3)
- Pub. Date : 2025
- Page : pp.033001-033001
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2025
AbstractUltraviolet (UV) photoacoustic microscopy has attracted lots of attention since it can provide histological images for disease diagnosis without any tissue processing or staining, holding great potential for rapid histopathology in hospitals. However, sometimes, the nuclear contrast in the images is relatively low due to the high UV absorption of various surrounding biomolecules (e.g., heme, myoglobin, lipids, etc.), resulting in low diagnostic accuracy. Here, a label‐free dual‐modality imaging system with ultraviolet photoacoustic and auto‐fluorescence (PAAF) microscopy is proposed, which can obtain photon absorption‐induced PA and AF images simultaneously using only one UV pulsed laser. With the opposite contrast acquired in the PA and AF images and the image fusion technique, this proposed PAAF microscopy enables high‐contrast and high‐sensitivity histological imaging for various tissues, even under a low excitation energy of 0.7 nJ and a high pulse‐to‐pulse energy fluctuation of ≈30%. Mouse brain, kidney, liver, lung, and human lung tissues processed by different clinical protocols have been imaged to demonstrate the versatility of PAAF microscopy, showing its promising applications in surgical pathology.- Book : ()
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2025
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2025
- Book : ()
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2025
Molecular clouds (MCs) are the places where stars are formed and their feedback starts to take place, regulating the evolution of galaxies. Therefore, MCs represent the critical scale at which to study how ultraviolet (UV) photons emitted by young stars are reprocessed in the far-infrared (FIR) by interaction with dust grains, thereby determining the multiwavelength continuum emission of galaxies. Our goal is to analyze the UV and IR emission of a MC at different stages of its evolution and relate its absorption and emission properties with its morphology and star formation rate. Such a study is fundamental to determining how the properties of MCs shape the emission from entire galaxies. We considered a radiation-hydrodynamic simulation of a MC with self-consistent chemistry treatment. The MC has a mass of M_ MC is resolved down to a scale of $0.06 pc$, and evolves for ≃ 2.4 Myr after the onset of star formation. We post-processed the simulation via Monte Carlo radiative transfer calculations to compute the detailed UV-to-FIR emission of the MC. Such results were compared with data from physically motivated analytical models, other simulations, and observations. We find that the simulated MC is globally UV-optically thick, but optically thin channels allow for photon escape ($0.1%-10%$), a feature that is not well captured in analytical models. The dust temperature spans a wide range (T_ dust ∼ 20-300 K) depending on the dust-to-stellar geometry, which is reproduced reasonably well by analytical models. However, the complexity of the dust temperature distribution is not captured in the analytical models, as is evidenced by the 10 K (20 K) difference in the mass (luminosity) average temperature. Indeed, the total IR luminosity is the same in all the models, but the IR emission peaks at shorter wavelengths in the analytical ones. Compared to a sample of Galactic clouds and other simulations, our spectral energy distribution (SED) is consistent with mid-IR data, but peaks at shorter wavelengths in the IR. This is due to a lack of cold dust, as a consequence of the high gas -- and thus dust -- consumption in our simulated MC. The attenuation properties of our MC change significantly with time, evolving from a Milky-Way-like relation to a flatter, featureless one. On the IRX-β plane, the MC position strongly depends on the observing direction and on its evolutionary stage. When the MC starts to disperse, the cloud settles at log( IRX) ∼ 1 and β ∼ -0.5, slightly below most of the local empirical relations. This work represents an important test for MC simulations and a first step toward the implementation of a physically informed, sub-grid model in large-scale numerical simulations to describe the emission from unresolved MC scales and its impact on the global galaxy SED.- Book : ()
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