193 research outputs found
Background-deflection Brillouin microscopy reveals altered biomechanics of intracellular stress granules by ALS protein FUS
Altered cellular biomechanics have been implicated as key photogenic triggers in age-related diseases. An aberrant liquid-to-solid phase transition, observed in in vitro reconstituted droplets of FUS protein, has been recently proposed as a possible pathogenic mechanism for amyotrophic lateral sclerosis (ALS). Whether such transition occurs in cell environments is currently unknown as a consequence of the limited measuring capability of the existing techniques, which are invasive or lack of subcellular resolution. Here we developed a non-contact and label-free imaging method, named background-deflection Brillouin microscopy, to investigate the three-dimensional intracellular biomechanics at a sub-micron resolution. Our method exploits diffraction to achieve an unprecedented 10,000-fold enhancement in the spectral contrast of single-stage spectrometers, enabling, to the best of our knowledge, the first direct biomechanical analysis on intracellular stress granules containing ALS mutant FUS protein in fixed cells. Our findings provide fundamental insights on the critical aggregation step underlying the neurodegenerative ALS disease
Insight on Hole-Hole Interaction and Magnetic Order from Dichroic Auger-Photoelectron Coincidence Spectra
The absence of sharp structures in the core-valence-valence Auger line shapes
of partially filled bands has severely limited the use of electron spectroscopy
in magnetic crystals and other correlated materials. Here by a novel interplay
of experimental and theoretical techniques we achieve a combined understanding
of the Photoelectron, Auger % and Auger-Photoelectron
Coincidence Spectra (APECS) of CoO. This is a prototype antiferromagnetic
material in which the recently discovered Dichroic Effect in Angle Resolved
(DEAR) APECS reveals a complex pattern in the strongly correlated Auger line
shape. A calculation of the \textit{unrelaxed} spectral features explains the
pattern in detail, labeling the final states by the total spin. The present
theoretical analysis shows that the dichroic effect arises from a
spin-dependence of the angular distribution of the photoelectron-Auger electron
pair detected in coincidence, and from the selective power of the dichroic
technique in assigning different weights to the various spin components. Since
the spin-dependence of the angular distribution exists in the antiferromagnetic
state but vanishes at the N\'eel temperature, the DEAR-APECS technique detects
the phase transition from its local effects, thus providing a unique tool to
observe and understand magnetic correlations in such circumstances, where the
usual methods (neutron diffraction, specific heat measurements) are not
applicable.Comment: Accepted by: Physical Review Letter
Global Transformer Architecture for Indoor Room Temperature Forecasting
A thorough regulation of building energy systems translates in relevant energy savings and in a better comfort for the occupants. Algorithms to predict the thermal state of a building on a certain time horizon with a good confidence are essential for the implementation of effective control systems. This work presents a global Transformer architecture for indoor temperature forecasting in multi-room buildings, aiming at optimizing energy consumption and reducing greenhouse gas emissions associated with HVAC systems. Recent advancements in deep learning have enabled the development of more sophisticated forecasting models compared to traditional feedback control systems. The proposed global Transformer architecture can be trained on the entire dataset encompassing all rooms, eliminating the need for multiple room-specific models, significantly improving predictive performance, and simplifying deployment and maintenance. Notably, this study is the first to apply a Transformer architecture for indoor temperature forecasting in multi-room buildings. The proposed approach provides a novel solution to enhance the accuracy and efficiency of temperature forecasting, serving as a valuable tool to optimize energy consumption and decrease greenhouse gas emissions in the building sector.publishedVersio
Global Transformer Architecture for Indoor Room Temperature Forecasting
A thorough regulation of building energy systems translates in relevant
energy savings and in a better comfort for the occupants. Algorithms to predict
the thermal state of a building on a certain time horizon with a good
confidence are essential for the implementation of effective control systems.
This work presents a global Transformer architecture for indoor temperature
forecasting in multi-room buildings, aiming at optimizing energy consumption
and reducing greenhouse gas emissions associated with HVAC systems. Recent
advancements in deep learning have enabled the development of more
sophisticated forecasting models compared to traditional feedback control
systems. The proposed global Transformer architecture can be trained on the
entire dataset encompassing all rooms, eliminating the need for multiple
room-specific models, significantly improving predictive performance, and
simplifying deployment and maintenance. Notably, this study is the first to
apply a Transformer architecture for indoor temperature forecasting in
multi-room buildings. The proposed approach provides a novel solution to
enhance the accuracy and efficiency of temperature forecasting, serving as a
valuable tool to optimize energy consumption and decrease greenhouse gas
emissions in the building sector
Non-Ischemic Scar Underlines Ventricular Arrhythmias in Kearns-Sayre Syndrome
Kearns-Sayre syndrome (KSS) is a rare mitochondrial disease in which cardiac involvement has been associated with poor prognosis. Although the most common clinical manifestation is progressive conduction system impairment, patients can suffer from ventricular arrhythmias. Yet, they show a high prevalence of sudden cardiac death, whose etiopathological mechanism is not completely understood. Cardiac magnetic resonance is a rising tool to detect subclinical heart involvement in many heart diseases and was recently able to detect nonischemic scar, which is an arrhythmogenic substrate, in patients affected by KSS
Electronic structure of copper phthalocyanine:An experimental and theoretical study of occupied and unoccupied levels
An experimental and theoretical study of the electronic structure of copper phthalocyanine (CuPc) molecule is presented. We performed x-ray photoemission spectroscopy (XPS) and photoabsorption [x-ray absorption near-edge structure (XANES)] gas phase experiments and we compared the results with self-consistent field, density functional theory (DFT), and static-exchange theoretical calculations. In addition, ultraviolet photoelectron spectra (UPS) allowed disentangling several outer molecular orbitals. A detailed study of the two highest occupied orbitals (having a(1u) and b(1g) symmetries) is presented: the high energy resolution available for UPS measurements allowed resolving an extra feature assigned to vibrational stretching in the pyrrole rings. This observation, together with the computed DFT electron density distributions of the outer valence orbitals, suggests that the a(1u) orbital (the highest occupied molecular orbital) is mainly localized on the carbon atoms of pyrrole rings and it is doubly occupied, while the b(1g) orbital, singly occupied, is mainly localized on the Cu atom. Ab initio calculations of XPS and XANES spectra at carbon K-edge of CuPc are also presented. The comparison between experiment and theory revealed that, in spite of being formally not equivalent, carbon atoms of the benzene rings experience a similar electronic environment. Carbon K-edge absorption spectra were interpreted in terms of different contributions coming from chemically shifted C 1s orbitals of the nonequivalent carbon atoms on the inner ring of the molecule formed by the sequence of CN bonds and on the benzene rings, respectively, and also in terms of different electronic distributions of the excited lowest unoccupied molecular orbital (LUMO) and LUMO+1. In particular, the degenerate LUMO appears to be mostly localized on the inner pyrrole ring
Carbon nanostructures for directional light dark matter detection
Carbon nanostructures offer exciting new possibilities in the detection of light dark matter. A darkmatter particle with mass between 1 MeV and 1 GeV scattering off an electron in the carbon wouldtransfer sufficient energy to extract the electron from the lattice. In 2D materials, such as grapheneor carbon nanotubes, these electrons would be released directly into the vacuum, avoiding theirre-absorption in the medium. We present two novel detector concepts: a ’Graphene-FET’ design,based on graphene sheets, developed at Princeton University; and a ’Dark-PMT’ based on alignedcarbon nanotubes, developed in University of Rome Sapienza. We discuss their light dark matterdiscovery potential, the status of the RD, and the recent commissioning of a state-of-the-art carbonnanotube growing facility in Rome
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