Autonomous University of Baja California

Solar ultraviolet (UV) radiation is the primary etiological factor in the development of several cutaneous malignancies, including carcinomas. In this context, the use of sunscreen formulations usually helps to prevent and reduce UV skin damage. The aim of this work was to explore the impact of the process conditions on some relevant physicochemical properties in sunscreens with a formulation based on quercetin Pickering emulsions stabilized with ZnO particles. Four formulations were prepared by controlling the speed and homogenization time using green coffee oil as the external phase and a mixture of stabilizers, water, and polyethylene glycol as the dissolution media. The stability of the emulsified systems was analyzed in terms of time after 28 days of storage by optical microscopy and digital image analysis to determine the mean particle size. The Turbiscan Stability Index (TSI), Sun Protection Factor (SPF), rheological behavior, and antioxidant activity were also evaluated. The system with the highest physical stability, minimal changes in rheological properties, and superior stability during storage time with respect to breakage phenomena was obtained at 15,000 rpm/2 min, with a SPF of 40 and exhibiting one of the highest antioxidant capacities compared to other treatments. This stability was constant during the evaluation period. With these results we established the optimal conditions for the potential development of sunscreens with desirable attributes to reduce the harmful effects of UV radiation in addition to establishing the encapsulation conditions of bioactive compounds and facilitating its scale-up.

We present the theory and experimental realization of a quantum polarization-displacement receiver for photonic communications with laser coherent states modulated in their polarization degree of freedom, employing an unconditionally polarization-nulling photon counting scheme. We describe the quantum detection analysis for Polarization Shift Keying (PolSK) modulation formats with laser coherent states, deriving their theoretical performance bounds in error probability and mutual information; and we propose a receiver structure based on a polarization-displacement technique, inspired on the conventional quadrature-displacement schemes employed in the reception of Phase Shift Keying (PSK) modulation formats. Experimentally, we implement our coherent states receiver in a polarization-nulling configuration, employing linear optics for the polarization rotations and displacement, with photon counting at the telecommunications wavelength of 1550 nm, and performing post-detection count–to–voltage operations and logical decision with optimized photon number thresholds; additionally, as a reference, we also implement a quadrature-nulling receiver for a binary PSK format. We perform measurements on the symbol error probability of our receiver, as a function of the photon number of the received photonic signal, finding good agreement with the theoretical estimation at low photon numbers. This receiving structure has advantages over the conventional polarization-splitting and separate photon counting schemes, which is of interest in quantum communications, quantum cryptography and other fields in quantum information.

Introduction:Sleep quality is recognized as a key determinant of sports performance, yet sleep disturbances are commonly observed among athletes, with a higher prevalence being reported in females. This study aimed to examine sex-specific associations of sleep disturbances with cardiorespiratory fitness, body composition, and metabolic flexibility in athletes.Methods:Fifty-nine athletes (n = 22 females, 18-35 yr, 8%-45% body fat) underwent a 3-h assessment, including validated questionnaires for assessing insomnia severity, daytime sleepiness, sleep quality, and psychological strain (i.e., perceived stress and anxiety levels). Bioelectrical impedance and indirect calorimetry were used for body composition and resting metabolism assessment, respectively, while near-infrared spectroscopy and a graded cardiopulmonary exercise test were applied to determine peak oxygen uptake, ventilatory thresholds, muscle O2 saturation, and maximal fat oxidation. Partial correlations and multiple regression analyses were used to explore associations between sleep disorders, fitness components, and physiological outcomes.Results:About 63% of athletes reported insomnia symptoms, with higher insomnia severity (effect size: 0.54, P = 0.04) and anxiety scores (effect size: 0.33, P = 0.03) in females. Insomnia severity was a significant negative predictor of the respiratory compensation point (beta = -0.09; P = 0.04), while the sleep quality index was inversely associated with the ventilatory threshold (beta = -0.63; P = 0.04), independent of sex and fitness level. No associations were found between sleep quality and disturbances with body composition, muscle O2 saturation, or fat oxidation rates.Conclusion:Insomnia severity and poor sleep quality contribute to an impaired ventilatory efficiency during low-to-moderate intensity exercise, having no influence on cardiovascular fitness and metabolic flexibility. Thus, enhancing sleep hygiene may improve endurance training adaptations in athletes regardless of sex and fitness level.

This work presents an alternating voltage-induced electrochemical synthesis strategy for the controlled formation of hierarchical selenium nanoclusters in colloidal state. The method enables the generation of primary trigonal selenium nanoparticles that self-assemble into stable nanoclusters through a Se⁰/Se(IV) redox cycling mechanism. Structural and physicochemical analyses confirm the formation of crystalline t-Se nanostructures stabilized by citrate-mediated surface interactions, resulting in enhanced colloidal stability and controlled growth. Unlike conventional chemical or green routes, this electrochemical approach allows modulation of nucleation and assembly through alternating potential control, providing reproducibility and architectural precision. The proposed mechanism highlights the synergistic interplay between electrochemical oxidation–reduction processes and chemical reduction, offering a scalable platform for the synthesis of hierarchical non-metallic nanostructures with potential catalytic and biomedical relevance. Colloidal Se-nanoclusters.