@article{18762, abstract = {Consider the random variable $\mathrm{Tr}( f_1(W)A_1\dots f_k(W)A_k)$ where $W$ is an $N\times N$ Hermitian Wigner matrix, $k\in\mathbb{N}$, and choose (possibly $N$-dependent) regular functions $f_1,\dots, f_k$ as well as bounded deterministic matrices $A_1,\dots,A_k$. We give a functional central limit theorem showing that the fluctuations around the expectation are Gaussian. Moreover, we determine the limiting covariance structure and give explicit error bounds in terms of the scaling of $f_1,\dots,f_k$ and the number of traceless matrices among $A_1,\dots,A_k$, thus extending the results of [Cipolloni, Erdős, Schröder 2023] to products of arbitrary length $k\geq2$. As an application, we consider the fluctuation of $\mathrm{Tr}(\mathrm{e}^{\mathrm{i} tW}A_1\mathrm{e}^{-\mathrm{i} tW}A_2)$ around its thermal value $\mathrm{Tr}(A_1)\mathrm{Tr}(A_2)$ when $t$ is large and give an explicit formula for the variance.}, author = {Reker, Jana}, issn = {1083-6489}, journal = {Electronic Journal of Probability}, publisher = {Institute of Mathematical Statistics}, title = {{Multi-point functional central limit theorem for Wigner matrices}}, doi = {10.1214/24-EJP1247}, volume = {29}, year = {2024}, } @article{17154, abstract = {We compute the deterministic approximation for mixed fluctuation moments of products of deterministic matrices and general Sobolev functions of Wigner matrices. Restricting to polynomials, our formulas reproduce recent results of Male et al. (Random Matrices Theory Appl. 11(2):2250015, 2022), showing that the underlying combinatorics of non-crossing partitions and annular non-crossing permutations continue to stay valid beyond the setting of second-order free probability theory. The formulas obtained further characterize the variance in the functional central limit theorem given in the recent companion paper (Reker in Preprint, arXiv:2204.03419, 2023). and thus allow identifying the fluctuation around the thermal value in certain thermalization problems.}, author = {Reker, Jana}, issn = {1572-9656}, journal = {Mathematical Physics, Analysis and Geometry}, number = {3}, publisher = {Springer Nature}, title = {{Fluctuation moments for regular functions of Wigner Matrices}}, doi = {10.1007/s11040-024-09483-y}, volume = {27}, year = {2024}, } @article{18656, abstract = {We consider the time evolution of the out-of-time-ordered correlator (OTOC) of two general observables and in a mean field chaotic quantum system described by a random Wigner matrix as its Hamiltonian. We rigorously identify three time regimes separated by the physically relevant scrambling and relaxation times. The main feature of our analysis is that we express the error terms in the optimal Schatten (tracial) norms of the observables, allowing us to track the exact dependence of the errors on their rank. In particular, for significantly overlapping observables with low rank the OTOC is shown to exhibit a significant local maximum at the scrambling time, a feature that may not have been noticed in the physics literature before. Our main tool is a novel multi-resolvent local law with Schatten norms that unifies and improves previous local laws involving either the much cruder operator norm (cf. [10]) or the Hilbert-Schmidt norm (cf. [11]).}, author = {Cipolloni, Giorgio and Erdös, László and Henheik, Sven Joscha}, issn = {1095-0753}, journal = {Advances in Theoretical and Mathematical Physics}, number = {6}, pages = {2025--2083}, publisher = {International Press of Boston}, title = {{Out-of-time-ordered correlators for Wigner matrices}}, doi = {10.4310/ATMP.241031013250}, volume = {28}, year = {2024}, } @article{17326, abstract = {Magnetic fields in the stellar interiors are key candidates to explain observed core rotation rates inside solar-like stars along their evolution. Recently, asteroseismic estimates of radial magnetic field amplitudes near the hydrogen-burning shell (H-shell) inside about 24 red giants (RGs) have been obtained by measuring frequency splittings from their power spectra. Using general Lorentz-stress (magnetic) kernels, we investigated the potential for detectability of near-surface magnetism in a 1.3 M⊙ star of supersolar metallicity as it evolves from a mid subgiant to a late subgiant into an RG. Based on these sensitivity kernels, we decompose an RG into three zones—deep core, H-shell, and near-surface. The subgiants instead required decomposition into an inner core, an outer core, and a near-surface layer. Additionally, we find that for a low-frequency g-dominated dipolar mode in the presence of a typical stable magnetic field, ∼25% of the frequency shift comes from the H-shell and the remaining from deeper layers. The ratio of the subsurface tangential field to the radial field in the H-burning shell decides if subsurface fields may be potentially detectable. For p-dominated dipole modes close to vmax, this ratio is around two orders of magnitude smaller in subgiant phases than the corresponding RG. Further, with the availability of magnetic kernels, we propose lower limits of field strengths in crucial layers in our stellar model during its evolutionary phases. The theoretical prescription outlined here provides the first formal way to devise inverse problems for stellar magnetism and can be seamlessly employed for slow rotators.}, author = {Bhattacharya, Shatanik and Das, Srijan B and Bugnet, Lisa Annabelle and Panda, Subrata and Hanasoge, Shravan M.}, issn = {1538-4357}, journal = {Astrophysical Journal}, number = {1}, publisher = {IOP Publishing}, title = {{Detectability of axisymmetric magnetic fields from the core to the surface of oscillating post-main-sequence stars}}, doi = {10.3847/1538-4357/ad4708}, volume = {970}, year = {2024}, } @article{18172, abstract = {Red Giant stars host solar-like oscillations which have mixed character, being sensitive to conditions both in the outer convection zone and deep within the interior. The properties of these modes are sensitive to both core rotation and magnetic fields. While asteroseismic studies of the former have been done on a large scale, studies of the latter are currently limited to tens of stars. We aim to produce the first large catalogue of both magnetic and rotational perturbations. We jointly constrain these parameters by devising an automated method for fitting the power spectra directly. We successfully apply the method to 302 low-luminosity red giants. We find a clear bimodality in core rotation rate. The primary peak is at δνrot = 0.32 μHz, and the secondary at δνrot = 0.47 μHz. Combining our results with literature values, we find that the percentage of stars rotating much more rapidly than the population average increases with evolutionary state. We measure magnetic splittings of 2σ significance in 23 stars. While the most extreme magnetic splitting values appear in stars with masses > 1.1M⊙, implying they formerly hosted a convective core, a small but statistically significant magnetic splitting is measured at lower masses. Asymmetry between the frequencies of a rotationally split multiplet has previously been used to diagnose the presence of a magnetic perturbation. We find that of the stars with a significant detection of magnetic perturbation, 43\% do not show strong asymmetry. We find no strong evidence of correlation between the rotation and magnetic parameters.}, author = {Hatt, Emily J. and Ong, J. M.Joel and Nielsen, Martin B. and Chaplin, William J. and Davies, Guy R. and Deheuvels, Sébastien and Ballot, Jérôme and Li, Gang and Bugnet, Lisa Annabelle}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {2}, pages = {1060--1076}, publisher = {Oxford University Press}, title = {{Asteroseismic signatures of core magnetism and rotation in hundreds of low-luminosity red giants}}, doi = {10.1093/mnras/stae2053}, volume = {534}, year = {2024}, } @misc{18967, abstract = {Background: We identified small molecule tricyclic pyrone compound CP2 as a mild mitochondrial complex I (MCI) inhibitor that induces neuroprotection in multiple mouse models of AD. One of the major concerns while targeting mitochondria is the production of reactive oxygen species (ROS). CP2 consists of two diastereoisomers, D1 and D2, with distinct activity and toxicity profiles. This study was designed to understand how structure of D1 and D2 affects their binding to MCI and the consequential impact on ROS production. Method: The X-ray crystallography and cryo-electron microscopy (cryo-EM) at global resolution of 3.25-3.27Å were employed to identify the molecular structure of D1 and D2 and the D1 binding to the isolated ovine MCI. The assessment of the MCI inhibition and the extent of ROS generation were done in isolated MCI and human neuroblastoma MC65 cells using flow cytometry, a Seahorse extracellular flux analyzer, and the kinetic studies. Result: In the closed conformation of MCI, D1 selectively binds to the deep Quinone-site (Qd) but not to the shallow Q-site (Qs), sharing the same binding pocket as rotenone. In the open MCI state, D1 exclusively binds to the Qs in contrast to rotenone, which binds Qd and Qs in both closed and open states. At the same concentrations, D1 inhibits respiration to a greater extent compared to D2 (5:1 ratio) and produces higher level of ROS. Conclusion:Cryo-EM unambiguously identified binding of D1 to both the Qd and Qs sites, contingent upon the conformational state of MCI. In contrast to rotenone, D1 binds Qd only in the closed conformation during catalytic cycle, leading to mild inhibition. Superimposing X-ray crystallography data of D1 and D2 onto cryo-EM data suggests that the orientation of the methyl group in D2 induces a flatter conformation, resulting in lower binding affinity to MCI, which correlates with lower inhibition and toxicity compared to D1. At physiologically relevant concentrations, CP2 (D1:D2 = 1:1) demonstrates low MCI inhibition yielding negligible ROS levels. This observation provides new insight into the absence of toxicity associated with CP2 treatment in vivo, further highlighting feasibility for the development of safe and efficacious MCI inhibitors.}, author = {Petrova, Olga and Trushin, Sergey A and Nguyen, Thi Kim Oanh and Ostroot, Mark and Schellenberg, Matthew and Johnson, Graham and Trushina, Eugenia and Sazanov, Leonid A}, booktitle = {Alzheimer's & Dementia}, issn = {1552-5279}, number = {S6}, publisher = {Wiley}, title = {{Structure‐activity relationship study of neuroprotective complex I inhibitor CP2}}, doi = {10.1002/alz.085971}, volume = {20}, year = {2024}, } @article{18581, abstract = {Background: Human induced pluripotent stem cells represent a scalable source of youthful tissue progenitors and secretomes for regenerative therapies. The aim of our study was to investigate the potential of conditioned medium (CM) from hiPSC-mesenchymal progenitors (hiPSC-MPs) to stimulate osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (MSCs). We also investigated whether prolonged cultivation or osteogenic pre-differentiation of hiPSC-MPs could enhance the stimulatory activity of CM. Methods: MSCs were isolated from 13 donors (age 20–90 years). CM derived from hiPSC-MPs was added to the MSC cultures and the effects on proliferation and osteogenic differentiation were examined after 14 days and 6 weeks. The stimulatory activity of hiPSC-MP-CM was compared with the activity of MSC-derived CM and with the activity of CM prepared from hiPSC-MPs pre-cultured in growth or osteogenic medium for 14 days. Comparative proteomic analysis of CM was performed to gain insight into the molecular components responsible for the stimulatory activity. Results: Primary bone marrow-derived MSC exhibited variability, with a tendency towards lower proliferation and tri-lineage differentiation in older donors. hiPSC-MP-CM increased the proliferation and alkaline phosphatase activity of MSC from several adult/aged donors after 14 days of continuous supplementation under osteogenic conditions. However, CM supplementation failed to improve the mineralization of MSC pellets after 6 weeks under osteogenic conditions. hiPSC-MP-CM showed greater enhancement of proliferation and ALP activity than CM derived from bone marrow-derived MSCs. Moreover, 14-day cultivation but not osteogenic pre-differentiation of hiPSC-MPs strongly enhanced CM stimulatory activity. Quantitative proteomic analysis of d14-CM revealed a distinct profile of components that formed a highly interconnected associations network with two clusters, one functionally associated with binding and organization of actin/cytoskeletal components and the other with structural constituents of the extracellular matrix, collagen, and growth factor binding. Several hub proteins were identified that were reported to have functions in cell-extracellular matrix interaction, osteogenic differentiation and development. Conclusions: Our data show that hiPSC-MP-CM enhances early osteogenic differentiation of human bone marrow-derived MSCs and that prolonged cultivation of hiPSC-MPs enhances CM-stimulatory activity. Proteomic analysis of the upregulated protein components provides the basis for further optimization of hiPSC-MP-CM for bone regenerative therapies.}, author = {Marolt Presen, Darja and Goeschl, Vanessa and Hanetseder, Dominik and Ogrin, Laura and Stetco, Alexandra Larissa and Tansek, Anja and Pozenel, Laura and Bruszel, Bella and Mitulovic, Goran and Oesterreicher, Johannes and Zipperle, Johannes and Schaedl, Barbara and Holnthoner, Wolfgang and Grillari, Johannes and Redl, Heinz}, issn = {1757-6512}, journal = {Stem Cell Research and Therapy}, publisher = {Springer Nature}, title = {{Prolonged cultivation enhances the stimulatory activity of hiPSC mesenchymal progenitor-derived conditioned medium}}, doi = {10.1186/s13287-024-03960-5}, volume = {15}, year = {2024}, } @article{18904, abstract = {The Planetary Transits and Oscillations of stars mission (PLATO) will allow us to measure surface rotation and monitor photometric activity of tens of thousands of main sequence solar-type and subgiant stars. This paper is the first of a series dedicated to the preparation of the analysis of stellar surface rotation and photospheric activity with the near-future PLATO data. We describe in this work the strategy that will be implemented in the PLATO pipeline to measure stellar surface rotation, photometric activity, and long-term modulations. The algorithms are applied on both noise-free and noisy simulations of solar-type stars, which include activity cycles, latitudinal differential rotation, and spot evolution. PLATO simulated systematics are included in the noisy light curves. We show that surface rotation periods can be recovered with confidence for most of the stars with only six months of observations and that the recovery rate of the analysis significantly improves as additional observations are collected. This means that the first PLATO data release will already provide a substantial set of measurements for this quantity, with a significant refinement on their quality as the instrument obtains longer light curves. Measuring the Schwabe-like magnetic activity cycle during the mission will require that the same field be observed over a significant timescale (more than four years). Nevertheless, PLATO will provide a vast and robust sample of solar-type stars with constraints on the activity-cycle length. Such a sample is lacking from previous missions dedicated to space photometry.}, author = {Breton, S. N. and Lanza, A. F. and Messina, S. and Pagano, I. and Bugnet, Lisa Annabelle and Corsaro, E. and García, R. A. and Mathur, S. and Santos, A. R. G. and Aigrain, S. and Amard, L. and Brun, A. S. and Degott, L. and Noraz, Q. and Palakkatharappil, D. B. and Panetier, E. and Strugarek, A. and Belkacem, K. and Goupil, M.-J and Ouazzani, R. M. and Philidet, J. and Renié, C. and Roth, O.}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, publisher = {EDP Sciences}, title = {{Measuring stellar surface rotation and activity with the PLATO mission. I. Strategy and application to simulated light curves}}, doi = {10.1051/0004-6361/202449893}, volume = {689}, year = {2024}, } @article{18306, abstract = {Neutral sodium (Na i) is an alkali metal with a favorable absorption cross section such that tenuous gases are easily illuminated at select transiting exoplanet systems. We examine both the time-averaged and time-series alkali spectral flux individually, over 4 nights at a hot Saturn system on a ∼2.8 day orbit about a Sun-like star WASP-49 A. Very Large Telescope/ESPRESSO observations are analyzed, providing new constraints. We recover the previously confirmed residual sodium flux uniquely when averaged, whereas night-to-night Na i varies by more than an order of magnitude. On HARPS/3.6 m Epoch II, we report a Doppler redshift at vΓ,NaD = + 9.7 ± 1.6 km s−1 with respect to the planet's rest frame. Upon examining the lightcurves, we confirm night-to-night variability, on the order of ∼1%–4% in NaD, rarely coinciding with exoplanet transit, not readily explained by stellar activity, starspots, tellurics, or the interstellar medium. Coincident with the ∼+10 km s−1 Doppler redshift, we detect a transient sodium absorption event dFNaD/F⋆ = 3.6% ± 1% at a relative difference of ΔFNaD(t) ∼ 4.4% ± 1%, lasting ΔtNaD ≳ 40 minutes. Since exoplanetary alkali signatures are blueshifted due to the natural vector of radiation pressure, estimated here at roughly ∼−5.7 km s−1, the radial velocity is rather at +15.4 km s−1, far larger than any known exoplanet system. Given that the redshift magnitude vΓ is in between the Roche limit and dynamically stable satellite orbits, the transient sodium may be a putative indication of a natural satellite orbiting WASP-49 A b.}, author = {Oza, Apurva V. and Seidel, Julia V. and Hoeijmakers, H. Jens and Unni, Athira and Kesseli, Aurora Y. and Schmidt, Carl A. and Sivarani, Thirupathi and Bello-Arufe, Aaron and Gebek, Andrea and Meyer Zu Westram, Moritz and Sousa, Sérgio G. and Lopes, Rosaly M.C. and Hu, Renyu and De Kleer, Katherine and Fisher, Chloe and Charnoz, Sébastien and Baker, Ashley D. and Halverson, Samuel P. and Schneider, Nick M. and Psaridi, Angelica and Wyttenbach, Aurélien and Torres Rodriguez, Santiago and Bhatnagar, Ishita and Johnson, Robert E.}, issn = {2041-8213}, journal = {Astrophysical Journal Letters}, number = {2}, publisher = {IOP Publishing}, title = {{Redshifted sodium transient near exoplanet transit}}, doi = {10.3847/2041-8213/ad6b29}, volume = {973}, year = {2024}, } @article{18528, abstract = {The recent measurement of magnetic field strength inside the radiative interior of red giant stars has opened the way toward full 3D characterization of the geometry of stable large-scale magnetic fields. However, current measurements, which are limited to dipolar (ℓ = 1) mixed modes, do not properly constrain the topology of magnetic fields due to degeneracies on the observed magnetic field signature on such ℓ = 1 mode frequencies. Efforts focused toward unambiguous detections of magnetic field configurations are now key to better understand angular momentum transport in stars. We investigated the detectability of complex magnetic field topologies (such as the ones observed at the surface of stars with a radiative envelope with spectropolarimetry) inside the radiative interior of red giants. We focused on a field composed of a combination of a dipole and a quadrupole (quadrudipole) and on an offset field. We explored the potential of probing such magnetic field topologies from a combined measurement of magnetic signatures on ℓ = 1 and quadrupolar (ℓ = 2) mixed mode oscillation frequencies. We first derived the asymptotic theoretical formalism for computing the asymmetric signature in the frequency pattern for ℓ = 2 modes due to a quadrudipole magnetic field. To access asymmetry parameters for more complex magnetic field topologies, we numerically performed a grid search over the parameter space to map the degeneracy of the signatures of given topologies. We demonstrate the crucial role played by ℓ = 2 mixed modes in accessing internal magnetic fields with a quadrupolar component. The degeneracy of the quadrudipole compared to pure dipolar fields is lifted when considering magnetic asymmetries in both ℓ = 1 and ℓ = 2 mode frequencies. In addition to the analytical derivation for the quadrudipole, we present the prospect for complex magnetic field inversions using magnetic sensitivity kernels from standard perturbation analysis for forward modeling. Using this method, we explored the detectability of offset magnetic fields from ℓ = 1 and ℓ = 2 frequencies and demonstrate that offset fields may be mistaken for weak and centered magnetic fields, resulting in underestimating the magnetic field strength in stellar cores. We emphasize the need to characterize ℓ = 2 mixed-mode frequencies, (along with the currently characterized ℓ = 1 mixed modes), to unveil the higher-order components of the geometry of buried magnetic fields and to better constrain angular momentum transport inside stars.}, author = {Das, Srijan B and Einramhof, Lukas and Bugnet, Lisa Annabelle}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, publisher = {EDP Sciences}, title = {{Unveiling complex magnetic field configurations in red giant stars}}, doi = {10.1051/0004-6361/202450918}, volume = {690}, year = {2024}, } @article{15335, abstract = {Stable matching of neurotransmitters with their receptors is fundamental to synapse function and reliable communication in neural circuits. Presynaptic neurotransmitters regulate the stabilization of postsynaptic transmitter receptors. Whether postsynaptic receptors regulate stabilization of presynaptic transmitters has received less attention. Here, we show that blockade of endogenous postsynaptic acetylcholine receptors (AChR) at the neuromuscular junction destabilizes the cholinergic phenotype in motor neurons and stabilizes an earlier, developmentally transient glutamatergic phenotype. Further, expression of exogenous postsynaptic gamma-aminobutyric acid type A receptors (GABAA receptors) in muscle cells stabilizes an earlier, developmentally transient GABAergic motor neuron phenotype. Both AChR and GABAA receptors are linked to presynaptic neurons through transsynaptic bridges. Knockdown of specific components of these transsynaptic bridges prevents stabilization of the cholinergic or GABAergic phenotypes. Bidirectional communication can enforce a match between transmitter and receptor and ensure the fidelity of synaptic transmission. Our findings suggest a potential role of dysfunctional transmitter receptors in neurological disorders that involve the loss of the presynaptic transmitter.}, author = {Godavarthi, Swetha K. and Hiramoto, Masaki and Ignatyev, Yuri and Levin, Jacqueline B. and Li, Hui Quan and Pratelli, Marta and Borchardt, Jennifer and Czajkowski, Cynthia and Borodinsky, Laura N. and Sweeney, Lora Beatrice Jaeger and Cline, Hollis T. and Spitzer, Nicholas C.}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {15}, publisher = {National Academy of Sciences}, title = {{Postsynaptic receptors regulate presynaptic transmitter stability through transsynaptic bridges}}, doi = {10.1073/pnas.2318041121}, volume = {121}, year = {2024}, } @article{18305, abstract = {Motor circuits represent the main output of the central nervous system and produce dynamic behaviors ranging from relatively simple rhythmic activities like swimming in fish and breathing in mammals to highly sophisticated dexterous movements in humans. Despite decades of research, the development and function of motor circuits remain poorly understood. Breakthroughs in the field recently provided new tools and tractable model systems that set the stage to discover the molecular mechanisms and circuit logic underlying motor control. Here, we describe recent advances from both vertebrate (mouse, frog) and invertebrate (nematode, fruit fly) systems on cellular and molecular mechanisms that enable motor circuits to develop and function and highlight conserved and divergent mechanisms necessary for motor circuit development.}, author = {Kratsios, Paschalis and Zampieri, Niccolò and Carrillo, Robert and Mizumoto, Kota and Sweeney, Lora Beatrice Jaeger and Philippidou, Polyxeni}, issn = {1529-2401}, journal = {The Journal of Neuroscience}, number = {40}, publisher = {Society for Neuroscience}, title = {{Molecular and cellular mechanisms of motor circuit development}}, doi = {10.1523/JNEUROSCI.1238-24.2024}, volume = {44}, year = {2024}, } @article{17189, abstract = {Supergranules, which are solar flow features with a lateral scale of 30,000–40,000 km and a lifetime of ~24 h, form a prominent component of the Sun’s convective spectrum. However, their internal flows, which can be probed only by helioseismology, are not well understood. We analyse dopplergrams recorded by the Solar Dynamics Observatory satellite to identify and characterize ~23,000 supergranules. We find that the vertical flows peak at a depth of ~10,000 km, and remain invariant over the full range of lateral supergranular scales, contrary to numerical predictions. We also infer that, within the local seismic resolution (≳5,000 km), downflows are ~40% weaker than upflows, indicating an apparent mass-flux imbalance. This may imply that the descending flows also comprise plumes, which maintain the mass balance but are simply too small to be detected by seismic waves. These results challenge the widely used mixing-length description of solar convection.}, author = {Hanson, Chris S. and Das, Srijan B and Mani, Prasad and Hanasoge, Shravan and Sreenivasan, Katepalli R.}, issn = {2397-3366}, journal = {Nature Astronomy}, pages = {1088--1101}, publisher = {Springer Nature}, title = {{Supergranular-scale solar convection not explained by mixing-length theory}}, doi = {10.1038/s41550-024-02304-w}, volume = {8}, year = {2024}, } @misc{22802, abstract = {MESA inlist file for the paper "Unveiling complex magnetic field configurations in red giant stars" (10.1051/0004-6361/202450918)}, author = {Das, Srijan B and Einramhof, Lukas and Bugnet, Lisa}, publisher = {Institute of Science and Technology Austria}, title = {{MESA inlist file}}, doi = {10.5281/zenodo.12804810}, year = {2024}, } @article{18480, abstract = {Caloric restriction (CR) can extend the organism life- and health-span by improving glucose homeostasis. How CR affects the structure-function of pancreatic beta cells remains unknown. We used single nucleus transcriptomics to show that CR increases the expression of genes for beta cell identity, protein processing, and organelle homeostasis. Gene regulatory network analysis reveal that CR activates transcription factors important for beta cell identity and homeostasis, while imaging metabolomics demonstrates that beta cells upon CR are more energetically competent. In fact, high-resolution microscopy show that CR reduces beta cell mitophagy to increase mitochondria mass and the potential for ATP generation. However, CR beta cells have impaired adaptive proliferation in response to high fat diet feeding. Finally, we show that long-term CR delays the onset of beta cell aging hallmarks and promotes cell longevity by reducing beta cell turnover. Therefore, CR could be a feasible approach to preserve compromised beta cell structure-function during aging and diabetes.}, author = {Dos Santos, Cristiane and Cambraia, Amanda and Shrestha, Shristi and Cutler, Melanie and Cottam, Matthew and Perkins, Guy and Lev-Ram, Varda and Roy, Birbickram and Acree, Christopher and Kim, Keun Young and Deerinck, Thomas and Dean, Danielle and Cartailler, Jean Philippe and Macdonald, Patrick E. and Hetzer, Martin W and Ellisman, Mark and Arrojo E Drigo, Rafael}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Calorie restriction increases insulin sensitivity to promote beta cell homeostasis and longevity in mice}}, doi = {10.1038/s41467-024-53127-2}, volume = {15}, year = {2024}, } @article{15316, abstract = {Genomic DNA that resides in the nuclei of mammalian neurons can be as old as the organism itself. The life span of nuclear RNAs, which are critical for proper chromatin architecture and transcription regulation, has not been determined in adult tissues. In this work, we identified and characterized nuclear RNAs that do not turn over for at least 2 years in a subset of postnatally born cells in the mouse brain. These long-lived RNAs were stably retained in nuclei in a neural cell type–specific manner and were required for the maintenance of heterochromatin. Thus, the life span of neural cells may depend on both the molecular longevity of DNA for the storage of genetic information and also the extreme stability of RNA for the functional organization of chromatin.}, author = {Zocher, Sara and Mccloskey, Asako and Karasinsky, Anne and Schulte, Roberta and Friedrich, Ulrike and Lesche, Mathias and Rund, Nicole and Gage, Fred H. and Hetzer, Martin W and Toda, Tomohisa}, issn = {1095-9203}, journal = {Science}, number = {6691}, pages = {53--59}, publisher = {AAAS}, title = {{Lifelong persistence of nuclear RNAs in the mouse brain}}, doi = {10.1126/science.adf3481}, volume = {384}, year = {2024}, } @misc{22865, abstract = {Dataset for Dos Santos et al, 2024}, author = {Arrojo e Drigo, Rafael}, publisher = {Repository}, title = {{Calorie restriction increases insulin sensitivity to promote beta cell homeostasis and longevity}}, doi = {10.5281/zenodo.6491943}, year = {2024}, } @misc{23143, abstract = {The attached trajectories illustrate the thinning of the membrane by DSC2, the impact of Y53A, R54A mutations on this process.In order to comply with the size limit, the initial conformations as well as one illustrative example of the final productive simulation of each simulated system are provided herewith. The initial conformations are provided in PDB format, while the final productive simulations are uploaded in NetCDF (AMBER) format. }, author = {Tang, Xuechen}, publisher = {Zenodo}, title = {{The interaction between the DSC2 and the cell membrane}}, doi = {10.5281/zenodo.13889273}, year = {2024}, } @article{13093, abstract = {The direct, solid state, and reversible conversion between heat and electricity using thermoelectric devices finds numerous potential uses, especially around room temperature. However, the relatively high material processing cost limits their real applications. Silver selenide (Ag2Se) is one of the very few n-type thermoelectric (TE) materials for room-temperature applications. Herein, we report a room temperature, fast, and aqueous-phase synthesis approach to produce Ag2Se, which can be extended to other metal chalcogenides. These materials reach TE figures of merit (zT) of up to 0.76 at 380 K. To improve these values, bismuth sulfide (Bi2S3) particles also prepared in an aqueous solution are incorporated into the Ag2Se matrix. In this way, a series of Ag2Se/Bi2S3 composites with Bi2S3 wt % of 0.5, 1.0, and 1.5 are prepared by solution blending and hot-press sintering. The presence of Bi2S3 significantly improves the Seebeck coefficient and power factor while at the same time decreasing the thermal conductivity with no apparent drop in electrical conductivity. Thus, a maximum zT value of 0.96 is achieved in the composites with 1.0 wt % Bi2S3 at 370 K. Furthermore, a high average zT value (zTave) of 0.93 in the 300–390 K range is demonstrated.}, author = {Nan, Bingfei and Li, Mengyao and Zhang, Yu and Xiao, Ke and Lim, Khak Ho and Chang, Cheng and Han, Xu and Zuo, Yong and Li, Junshan and Arbiol, Jordi and Llorca, Jordi and Ibáñez, Maria and Cabot, Andreu}, issn = {2637-6113}, journal = {ACS Applied Electronic Materials}, number = {5}, pages = {2807--215}, publisher = {American Chemical Society}, title = {{Engineering of thermoelectric composites based on silver selenide in aqueous solution and ambient temperature}}, doi = {10.1021/acsaelm.3c00055}, volume = {6}, year = {2024}, } @article{17124, abstract = {In recent years, solution processes have gained considerable traction as a cost-effective and scalable method to produce high-performance thermoelectric materials. The process entails a series of critical steps: synthesis, purification, thermal treatments, and consolidation, each playing a pivotal role in determining performance, stability, and reproducibility. We have noticed a need for more comprehensive details for each of the described steps in most published works. Recognizing the significance of detailed synthetic protocols, we describe here the approach used to synthesize and characterize one of the highest-performing polycrystalline p-type SnSe. In particular, we report the synthesis of SnSe particles in water and the subsequent surface treatment with CdSe molecular complexes that yields CdSe-SnSe nanocomposites upon consolidation. Moreover, the surface treatment inhibits grain growth through Zenner pinning of secondary phase CdSe nanoparticles and enhances defect formation at different length scales. The enhanced complexity in the CdSe-SnSe nanocomposite microstructure with respect to SnSe promotes phonon scattering and thereby significantly reduces the thermal conductivity. Such surface engineering provides opportunities in solution processing for introducing and controlling defects, making it possible to optimize the transport properties and attain a high thermoelectric figure of merit.}, author = {Fiedler, Christine and Liu, Yu and Ibáñez, Maria}, issn = {1940-087X}, journal = {Journal of Visualized Experiments}, number = {207}, publisher = {MyJove Corporation}, title = {{Solution-processed, surface-engineered, polycrystalline CdSe-SnSe exhibiting low thermal conductivity}}, doi = {10.3791/66278}, volume = {2024}, year = {2024}, }