Universidade Estadual Paulista (Unesp)

We study the group of surjective linear isometries on certain real Banach sequence spaces using the preservation of extreme points in the closed unit ball. Our main result provides a characterization of the extreme points of the dual unit ball of the James-Schreier space V 1 . As a consequence, we show that the only isometries on V 1 are ± I d . We also obtain a Banach-Stone-type result for Lorentz sequence spaces, analogous to one proved in [13] for Lorentz function spaces.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by dopaminergic neuron loss, and growing evidence highlights neuroinflammation as a key contributor to disease progression. Annexin A1 (AnxA1), a glucocorticoid-regulated protein with anti-inflammatory and pro-resolving functions, and its N-terminal peptide Ac2-26 have shown neuroprotective potential, but the mechanisms underlying their effects in PD remain unclear. Here, we investigated the effects of AnxA1 and Ac2-26 in a 6-hydroxydopamine (6-OHDA) mouse model of PD using C57BL/6 wild-type (AnxA1+/+) and AnxA1 knockout (AnxA1-/-) mice. Animals received a unilateral 6-OHDA injection into the striatum, followed by intraperitoneal injection of Ac2-26 or saline. Motor behavior, dopaminergic neuron survival, cytokine levels, and glial changes were analyzed. Ac2-26 improved motor performance and protected against 6-OHDA-induced dopaminergic degeneration in the striatum and substantia nigra (SN) of AnxA1+/+ mice, preventing the loss of tyrosine hydroxylase (TH)+ neurons. These protective effects were reduced in AnxA1-/- mice. Ac2-26 also modulated neuroinflammation in a genotype-dependent manner, increasing anti-inflammatory cytokines and limiting pro-inflammatory mediators in the SN of AnxA1+/+ animals. In females, genetic deletion of AnxA1 led to reduced TH expression, impaired behavioral recovery, and disruption of the estrous cycle. Overall, Ac2-26 confers neuroprotection through AnxA1-dependent regulation of neuroinflammation, dopaminergic integrity, and hormonal balance, supporting its potential as a therapeutic target in PD.

This study presents an innovative electroanalytical method for detecting the fungicide Fenpropimorph (FPM) in vegetable samples. Initial tests used various supporting electrolytes, with scan potentials from 0.00V to +1.60V on a boron-doped diamond electrode (BDD) and from 0.00V to -1.80V on a polished solid silver amalgam electrode (p-AgSAE) using square wave voltammetry (SWV). A small voltammetric peak appeared around +1.10V (vs. Ag/AgCl in KCl 3.00molL₋1) on BDD, while on p-AgSAE, a well-defined voltammetric peak was observed in all tested buffer solutions. Experimental conditions, including pH values and voltammetric parameters (pulse frequency, pulse amplitude, and scan increment), were optimized, resulting in a clearly defined peak on p-AgSAE with suitable intensity, position, and reproducibility for analytical purposes. Analytical parameters were calculated, and the method was applied to vegetable samples (lettuce, tomatoes, and potatoes), which were then compared with gas chromatography-mass spectrometry results. Greene's calculator indicated that the proposed procedure is a suitable analytical method for detecting FPM in complex samples.

We present an extensive investigation on the properties of Eu 3+ optical emissions associated with deformation of ZnO host applying an external hydrostatic pressure, combining in situ synchrotron X-ray diffraction and photoluminescence spectroscopy with first-principles calculations. A pressure-induced phase transition from the hexagonal wurtzite to the cubic rocksalt structure near 10 GPa is accompanied by complete quenching of the 5 D 0 → 7 F J emissions near the threshold, followed by a partial but reproducible recovery at higher pressures, likely associated with the emergence of structural disorder. Concurrently, as the crystal field strength increases, the Stark components of the emissions exhibit a systematic redshift (∼0.40 ± 0.02meV/GPa) and pressure-induced broadening (∼0.55 ± 0.02 meV/GPa). The first-principles calculations support the observed pressure-induced shifts in the Eu-4f states and emphasize the influence of lattice symmetry on their electronic environment. These findings establish hydrostatic pressure as a powerful tool for tuning rare-earth optical emissions through symmetry-driven and local-environment modifications, laying the foundation for pressure-engineered photonic functionalities and luminescent devices. • Pressure-driven wurtzite-to-rocksalt transition modulates Eu 3+ luminescence in ZnO. • The structural transition initiates at ∼5.8 GPa, with cubic dominance above 10GPa. • Redshift and Stark splitting due to enhanced lattice symmetry and crystal field. • DFT reveals symmetry-dependent reshaping of electronic states under compression. • Lattice symmetry control governs RE optical activity under extreme conditions.