We study the influence of the instantaneous appearance of a conformal Killing vector (CKV) in self-gravitating fluid spheres during their evolution. For doing that we introduce a tensor variable whose time dependence allows the existence of a CKV for a given value of the time-like coordinate. We consider adiabatic and dissipative fluids. The analysis of different relevant physical variables in this process provides a smoking gun signature from the emergence of CKV at some point of the evolution. Prospective applications of these results, as well as open questions and pending issues related to this problem, are discussed.
Se determinó la composición química del aceite virgen obtenido por presión mecánica de semillas de uva de las variedades Syrah, Tintorera y de una mezcla de las variedades Syrah-Tempranillo-Merlot. Métodos analíticos oficiales fueron empleados en la determinación de dos índices de calidad (acidez e índice de peróxidos), del perfil de ácidos grasos y para la cuantificación de los componentes minoritarios más importantes. Los valores de acidez e índice de peróxidos coincidieron con los señalados por el Codex Alimentarius para los aceites comestibles de buena calidad. El ácido linoleico fue el ácido graso más abundante en todas las muestras, representando alrededor del 65%, seguido por el ácido oleico con niveles cercanos al 25%. La concentración total de fitoesteroles se ubicó en el intervalo de 5179 hasta 5480 mg/kg siendo el β-sitosterol el más importante constituyendo más del 66% del total. El colesterol fue detectado en los aceites vírgenes provenientes de las variedades Syrah y Tintorera, con concentraciones inferiores al máximo permitido para los aceites vegetales comestibles. El ester 1-butanil-3-metil acetato, fue el componente volátil encontrado en mayor proporción con concentraciones de 5,4; 6,8 y 11,0 mg/kg para las variedades Syrah, Tintorera y la mezcla de semillas respectivamente. Otros compuestos volátiles también presentes en los aceites fueron el Trans-2-hexenal (0,1 a 0,5 mg/kg), E-2-pentenal (3,1 a 4,2 mg/kg), hexanal (1,4 a 1,9 mg/kg) y heptanal (0,1 a 0,3 mg/kg). Esos compuestos pueden ser los responsables de los aromas afrutados que se detectaron en todas las muestras de aceites vírgenes estudiadas. Los isómeros α y γ tocotrienoles, representaron más del 80% de los tococromanoles presentes, mientras que los tocoferoles constituyeron menos del 10%. El color verde intenso observado en los aceites fue asociado a la presencia de clorofila y otros pigmentos vegetales.
To systematically evaluate and update the evidence about photobiomodulation therapy (PBMT) as a therapy for the prevention and/or treatment of oral mucositis (OM) induced by antineoplastic therapies. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic literature search was conducted across PubMed, Web of Science, Scopus, and Embase as the primary databases. Additional searches were performed in the Virtual Health Library (VHL) and LILACS through the BIREME platform, as well as in Redalyc and the Wiley Online Library, covering the period from 2020 to 2026. Only randomized clinical trials published within the last six years investigating PBMT as a preventive or therapeutic intervention for oral mucositis (OM) in cancer patients receiving chemotherapy and/or radiotherapy were included. Seven studies comprising 329 patients were included. PBMT proved to be highly effective in the management of OM (RR 0.50, 95
Background: Simulation-based training is a critical component of robotic surgical education. While virtual reality platforms are well established for basic skills acquisition, they lack the ability to replicate tissue handling required for procedural simulation. Synthetic models have emerged as a promising alternative; however, formal validation is required prior to their integration into training curricula. This study aimed to establish the face and content validity of the International Medical Robotics Academy (IMRA) Surgical model for robotic transabdominal preperitoneal (TAPP) inguinal hernia repair. Methods: A prospective content validity study was conducted using an international expert panel. Surgeons with experience in robotic TAPP repair and prior exposure to the IMRA model were recruited. A 48-item survey instrument was developed and organized across domains including anatomical fidelity, procedural relevance, haptic properties, and educational utility. Items were rated on a 4-point Likert scale. Item-level content validity indices (I-CVI) were calculated, with a threshold of ≥ 0.78 for retention. The scale-level content validity index (S-CVI/Ave) was computed, with ≥ 0.90 considered acceptable. Face validity was assessed using five global rating items (1–10 scale). Results: Ten expert surgeons from three countries participated. The overall face validity score was 8.78/10, with all domains exceeding 8.0, including educational value (9.40) and procedural relevance (8.90). The S-CVI/Ave was 0.929. Of 48 items, 44 (91.7
We construct and analyse a class of static spherically symmetric spacetimes in general relativity sourced exclusively by classical electrostatic configurations. Using a spherically symmetric Painlev & eacute;-Gullstrand-like metric with unit lapse and a radial shift function, we develop piecewise-defined solutions where the interior geometry is flat and the exterior is supported by several sources inspired by electromagnetic distributions. These include point-charge-like fields, Yukawa-screened electric fields, dielectric layers, and Hulth & eacute;n-type field. The Einstein equations naturally impose a relation between the energy density and radial pressure, while the tangential pressure is derived from the metric. We systematically evaluate the classical energy conditions in each model and study the appearance of singular behaviour using Israel junction conditions. This framework offers an analytically tractable setting to explore the gravitational effects of physically simple, well-understood sources without resorting to exotic matter.
