5,563 results match your criteria: "Universita di Pisa[Affiliation]"

A 2D chiral microcavity based on apparent circular dichroism.

Nat Commun

April 2024

Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI, 53706, USA.

Engineering asymmetric transmission between left-handed and right-handed circularly polarized light in planar Fabry-Pérot (FP) microcavities would enable a variety of chiral light-matter phenomena, with applications in spintronics, polaritonics, and chiral lasing. Such symmetry breaking, however, generally requires Faraday rotators or nanofabricated polarization-preserving mirrors. We present a simple solution requiring no nanofabrication to induce asymmetric transmission in FP microcavities, preserving low mode volumes by embedding organic thin films exhibiting apparent circular dichroism (ACD); an optical phenomenon based on 2D chirality.

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Chromosome 22q11.2 deletion is among the strongest known genetic risk factors for neuropsychiatric disorders, including autism and schizophrenia. Brain imaging studies have reported disrupted large-scale functional connectivity in people with 22q11 deletion syndrome (22q11DS).

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The observation of WWγ production in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of 138  fb^{-1} is presented. The observed (expected) significance is 5.6 (5.

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RNA: The Unsuspected Conductor in the Orchestra of Macromolecular Crowding.

Chem Rev

April 2024

RNA Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy.

This comprehensive Review delves into the chemical principles governing RNA-mediated crowding events, commonly referred to as granules or biological condensates. We explore the pivotal role played by RNA sequence, structure, and chemical modifications in these processes, uncovering their correlation with crowding phenomena under physiological conditions. Additionally, we investigate instances where crowding deviates from its intended function, leading to pathological consequences.

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Cyanobacteria use large antenna complexes called phycobilisomes (PBSs) for light harvesting. However, intense light triggers non-photochemical quenching, where the orange carotenoid protein (OCP) binds to PBS, dissipating excess energy as heat. The mechanism of efficiently transferring energy from phycocyanobilins in PBS to canthaxanthin in OCP remains insufficiently understood.

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The isoproterenol-induced myocardial fibrosis: A biochemical and histological investigation.

Biomed Pharmacother

May 2024

Department of Veterinary Sciences, University of Pisa, via Delle Piagge 2-56124, Pisa, Italy; CISUP, Centro per l'Integrazione della Strumentazione dell'Università di Pisa, Lungarno Pacinotti 43, Pisa 56126, Italy.

The isoproterenol (ISO)-induced myocardial fibrosis is considered a reliable and repeatable experimental model characterized by a relatively low mortality rate. Although is well-known that ISO stimulates the β1 adrenergic receptors at the myocardial level, a high degree of heterogeneity emerges around the doses and duration of the treatment generating unclear results. Therefore, we propose to gain insights into the progression of ISO-induced myocardial fibrosis, in order to critically analyze and optimize the experimental model.

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A search is reported for near-threshold structures in the J/ψJ/ψ invariant mass spectrum produced in proton-proton collisions at sqrt[s]=13  TeV from data collected by the CMS experiment, corresponding to an integrated luminosity of 135  fb^{-1}. Three structures are found, and a model with quantum interference among these structures provides a good description of the data. A new structure is observed with a local significance above 5 standard deviations at a mass of 6638_{-38}^{+43}(stat)_{-31}^{+16}(syst)  MeV.

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Electronic Excited States from Physically Constrained Machine Learning.

ACS Cent Sci

March 2024

Laboratory of Computational Science and Modeling, Institut des Matériaux, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.

Data-driven techniques are increasingly used to replace electronic-structure calculations of matter. In this context, a relevant question is whether machine learning (ML) should be applied directly to predict the desired properties or combined explicitly with physically grounded operations. We present an example of an integrated modeling approach in which a symmetry-adapted ML model of an effective Hamiltonian is trained to reproduce electronic excitations from a quantum-mechanical calculation.

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Membrane fluctuations of human red blood cells investigated by the current signal noise in scanning ion conductance microscopy.

Micron

June 2024

Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (INO-CNR), Via Moruzzi 1, Pisa 56124, Italy. Electronic address:

Human red blood cells show submicron membrane fluctuations (CMFs) that have been mainly studied with optical microscopies. Although the functional role of this phenomenon is still uncertain, the amplitude of membrane fluctuations is considered as an indicator of mechanical resilience to the stress encountered in the capillary beds. We investigate here the membrane fluctuations in red blood cells using the scanning ion conductance microscopy (SICM), a scanning probe technique that avoids the probe-sample contact.

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Most of the northern hemisphere donkey breeds are faced with the risk of extinction, thus donkey reproduction is considered an emerging branch of theriogenology, and the management of artificial insemination and induction of ovulation is a crucial point in setting up preservation protocols. For four consecutive cycles, six jennies' ovarian activity was routinely monitored; an ultrasound examination was performed daily from the evidence of a follicle diameter ≥27 mm until ovulation. Upon reaching a follicular diameter ≥32 ± 2 mm (Hour 0), oestrous jennies were treated alternatively with 0.

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The replacement of synthetic and petroleum-based ingredients with greener alternatives of natural origin is an imperative issue in rubber technology for the tire industry. In this study, a glycerin-esterified maleated rosin resin, derived from natural resources, is examined as a potential tackifier in styrene-butadiene rubber (SBR) formulations. A comparison is made with two synthetic resins commonly used as tackifiers in tire manufacturing: a petroleum-derived aromatic resin and a phenolic resin.

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Convergently evolved placental villi show multiscale structural adaptations to differential placental invasiveness.

Biol Lett

March 2024

The Institute of Developmental Sciences, Human Development and Health, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.

Despite having a single evolutionary origin and conserved function, the mammalian placenta exhibits radical structural diversity. The evolutionary drivers and functional consequences of placental structural diversity are poorly understood. Humans and equids both display treelike placental villi, however these villi evolved independently and exhibit starkly different levels of invasiveness into maternal tissue (i.

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ATLAS measured the centrality dependence of the dijet yield using 165  nb^{-1} of p+Pb data collected at sqrt[s_{NN}]=8.16  TeV in 2016. The event centrality, which reflects the p+Pb impact parameter, is characterized by the total transverse energy registered in the Pb-going side of the forward calorimeter.

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Chemical Composition, Repellent, and Phytotoxic Potentials of the Fractionated Resin Essential Oil from Araucaria heterophylla Growing in Tunisia.

Chem Biodivers

May 2024

Laboratory of Heterocyclic Chemistry, Natural Products and Reactivity (LR11ES39), Team: Medicinal Chemistry and Natural Products, Faculty of Science of Monastir, University of Monastir, Avenue of Environment, 5019, Monastir, Tunisia Phone.

The resin essential oil (REO) of the Tunisian Araucaria heterophylla trunk bark was investigated for its chemical composition. Then, it was evaluated for its insecticidal and allelopathic activities. The REO was obtained by hydrodistillation for 9 h (yield of 4.

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Article Synopsis
  • The study examines Neolithic navigation in the Mediterranean by focusing on the construction and chronology of boats, particularly five canoes discovered at the La Marmotta site.
  • The analysis of these canoes and related nautical objects highlights the advanced technical skills of Neolithic societies.
  • This technological expertise was crucial for their expansion, enabling them to inhabit a vast area stretching from Cyprus to the Iberian Peninsula over several millennia.
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Rhodopsins are light-responsive proteins forming two vast and evolutionary distinct superfamilies whose functions are invariably triggered by the photoisomerization of a single retinal chromophore. In 2018 a third widespread superfamily of rhodopsins called heliorhodopsins was discovered using functional metagenomics. Heliorhodopsins, with their markedly different structural features with respect to the animal and microbial superfamilies, offer an opportunity to study how evolution has manipulated the chromophore photoisomerization to achieve adaptation.

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Prevalence and clinical outcomes of isolated or combined moderate to severe mitral and tricuspid regurgitation in patients with cardiac amyloidosis.

Eur Heart J Cardiovasc Imaging

June 2024

Cardiology, ASST Spedali Civili di Brescia; Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Piazzale Spedali Civili, 1, 25123 Brescia, Italy.

Article Synopsis
  • The study focused on the prevalence and impact of mitral regurgitation (MR) and tricuspid regurgitation (TR) in patients with cardiac amyloidosis (CA), highlighting a lack of existing research on this topic.
  • Among 538 patients analyzed, 44.6% had no significant MR/TR, while a significant portion experienced varying degrees of MR or TR, with common causes being atrial functional issues and right ventricular overload.
  • Results indicated that patients with MR/TR had worse health outcomes, including higher hospitalization rates for heart failure, more symptoms, and increased risk of death or worsening heart failure, with TR presenting the most severe risks.
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Using the gamma-index analysis for inter-fractional comparison of in-beam PET images for head-and-neck treatment monitoring in proton therapy: A Monte Carlo simulation study.

Phys Med

April 2024

Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, Largo Bruno Pontecorvo 3, Pisa, 56127, Italy; Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3, Pisa, 56127, Italy.

Article Synopsis
  • In-beam Positron Emission Tomography (PET) serves as a non-invasive method for monitoring treatment effects during proton therapy, focusing on challenges in clinical interpretation of anatomical changes.
  • This study examines the suitability of gamma-index analysis, commonly used for dose comparisons, to assess changes in in-beam PET distributions, particularly in head-and-neck patients.
  • Findings indicate that gamma-index analysis effectively identifies anatomical changes, with specific tolerance values established for accurate comparisons, highlighting the method's potential in tracking changes throughout treatment.
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The structure of the spirocyclic product obtained by reacting catechol with 1,1-dichloro-2-(chloromethyl)cyclopropane is shown by NMR and X-ray analysis to be that of a 2-methylcyclopropene (MeCP), instead of the previously reported 2-methylenecyclopropane (MCP) one. The study of the equilibration between the two isomeric forms by experimental and computational means (including both Density Functional Theory - DFT - and Coupled Cluster with single, double, and perturbative triple excitations - CCSD(T) - calculations) revealed that, at variance with most of the alkylidenecyclopropane/alkylcyclopropene systems described to date, for the compounds of the present study the MeCP derivative is more stable by≈ 2.5-3.

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We developed a fluorescent molecular probe based on gold nanoparticles functionalized with ,'-bis(2-(1-piperazino)ethyl)-3,4,9,10-perylenetetracarboxylic acid diimide dihydrochloride, and these probes exhibit potential for applications in microscopic thermometry. The intensity of fluorescence was affected by changes in temperature. Chemical environments, such as different buffers with the same pH, also resulted in different fluorescence intensities.

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Ectopic pregnancy (EP) is a life-threatening disease that affects humans and other mammals. Tumors causing ruptures of the reproductive tract have been identified as possible predisposing factors in human and veterinary medicine. We here describe a case of concomitant ectopic pregnancy and lymphoma in a Eurasian red squirrel found deceased in Italy and submitted to the public health laboratory Istituto Zooprofilattico Sperimentale del Lazio e della Toscana (IZSLT) for post-mortem examination.

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We introduce a quantum mechanics/molecular mechanics semiclassical method for studying the solvation process of molecules in water at the nuclear quantum mechanical level with atomistic detail. We employ it in vibrational spectroscopy calculations because this is a tool that is very sensitive to the molecular environment. Specifically, we look at the vibrational spectroscopy of thymidine in liquid water.

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Ocean warming and acidification, decreases in dissolved oxygen concentrations, and changes in primary production are causing an unprecedented global redistribution of marine life. The identification of underlying ecological processes underpinning marine species turnover, particularly the prevalence of increases of warm-water species or declines of cold-water species, has been recently debated in the context of ocean warming. Here, we track changes in the mean thermal affinity of marine communities across European seas by calculating the Community Temperature Index for 65 biodiversity time series collected over four decades and containing 1,817 species from different communities (zooplankton, coastal benthos, pelagic and demersal invertebrates and fish).

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Article Synopsis
  • The study uses an unsupervised anomaly-detection technique to search for new resonances in particle collision data from the ATLAS experiment at the Large Hadron Collider, focusing on events with electrons or muons.
  • An autoencoder is trained on the data to identify unusual patterns by analyzing the reconstruction loss, with the research examining nine invariant mass spectra involving pairs of jets and leptons or photons.
  • No significant anomalies were found, leading to the establishment of limits on potential Gaussian signals of various widths for the analyzed invariant masses in the anomalous regions.
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Serotonin-releasing fibers depart from the raphe nuclei to profusely innervate the entire central nervous system, displaying in some brain regions high structural plasticity in response to genetically induced abrogation of serotonin synthesis. Chronic fluoxetine treatment used as a tool to model peri-physiological, clinically relevant serotonin elevation is also able to cause structural rearrangements of the serotonergic fibers innervating the hippocampus. Whether this effect is limited to hippocampal-innervating fibers or extends to other populations of axons is not known.

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