No abstract

No abstract

Photodynamic therapy (PDT) is a treatment modality that can be indicated for several cancer types and precancer lesions. One of the main applications of PDT is the treatment of superficial skin lesions such as basal cell carcinoma, Bowen's disease and actinic keratosis. Three elements are necessary in PDT, a photosensitizer (PS); light at specific wavelength to be absorbed by the PS, and molecular oxygen. A typical PS used for skin lesion is protoporphyrin IX (PpIX), which is an intrinsic PS; its production is stimulated by a pro-drug, such as 5-aminolevulinic acid (ALA). Before starting a treatment, it is very important to follow up the PpIX production (to ensure that enough PS was produced prior to a PDT application) and, during a PDT session, to monitor its photodegradation (as it is evidence of the photodynamic effect taking place). The aim of this paper is to present a unique device, LINCE (MMOptics -São Carlos, Brazil), that brings together two probes that can, respectively, allow for fluorescence imaging and work as a light source for PDT treatment. The fluorescence probe of the system is optically based on 400 nm LED (light emitting diodes) arrays that allow observing the fluorescence emission over 450 nm. The PDT illumination probe options are constituted of 630 nm LED arrays for small areas and, for large areas, of both 630 nm and 450 nm LED arrays. Joining both functions at the same device makes PDT treatment simpler, properly monitorable and, hence, more clinically feasible. LINCE has been used in almost 1000 PDT treatments of superficial skin lesions in Brazil, with 88.4% of clearance of superficial BCC.

We have measured the total collisional loss rate for ultracold sodium atoms held in a magneto-optical trap operating on the D1 line. The collisional rate is extracted from the decay of the fluorescence from trapped atoms. We observe an intensity dependence corresponding to radiative escape and hyperfine changing collisions in the trap. The results obtained are compared with previous measurements for traps operating on the D2 line.

No abstract

No abstract

No abstract

utilizado no trabalho, em especial ao Edivaldo Cardoso. • Aos técnicos da oficina mecânica pela confecção das peças utilizadas nos lasers e armadilhas, sob orientação de Carlos Nazareth. • Ao Sílvio Tonissi e Marcelo Urso pelo auxilio imprecindível em eletrônica.