Patterns and prognostic impact of CNS infiltration in adults with newly diagnosed acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is highly associated with central nervous system (CNS) infiltration and can be associated with higher risk of relapse. Conventional cytology (CC) is the traditional method for diagnosing CNS infiltration, although the use of immunophenotyping by flow cytometry (FC) has gained prominence in recent years due to its higher sensitivity. Also, some authors have proposed that CSF contamination by a traumatic lumbar puncture (TLP) could have a clinical impact. This retrospective study accessed the impact of CNS infiltration by CC or FC on overall survival, event-free survival, and relapse rate. In a cohort of 105 newly diagnosed ALL patients, CNS1, CNS2, and CNS3 status were found in 84%, 14%, and 2%, respectively. We found that extramedullary disease at the diagnosis, higher leukocyte counts, and higher blast percentage were associated with a positive CC. Sensitivity and specificity of CC were 53% and 98%, respectively. Three-year overall survival was 42.5%. Conversely, TLP was not associated with a positive CC nor had an impact on relapse rates. In multivariate analysis, a positive CC was associated with an increased relapse rate (HR 2.074, p = 0.037), while its detection by FC did not associate with this endpoint. Survival rates seem to be increasing over the last years by the adoption of a stratified CNS prophylaxis risk strategy. CSF contamination does not represent a major concern according to our report, as it did not increase CNS involvement or relapse rates.

Reviewing the effect of aggregates in Rhodamine 6G aqueous solution on fluorescence quantum efficiency

Rhodamines constitute a class of dyes extensively investigated and applied in various contexts, primarily attributed to their high luminescence quantum yield. This study delves into the impact of aggregation on the thermal and optical properties of Rhodamine 6G (R-6G) solutions in distilled water. Examined properties encompass thermal diffusivity (D), temperature coefficient of the refractive index (dn/dT), fluorescence quantum efficiency (η), and energy transfer (ET). These parameters were assessed through thermal lens (TL) and conventional absorption and emission spectroscopic techniques. The dimerization of R-6G solutions was revisited, revealing that an increase in R-6G concentration alters the features of absorption and emission spectra due to dimer formation, resulting in unexpected behavior of η. Consequently, we introduce a novel model for the fraction of absorbed energy converted into heat (φ), which accounts for emissions from both monomers and dimers. Employing this model, we investigate and discuss the concentration-dependent behaviors of η for monomers (ηm) and dimers (ηd). Notably, our findings demonstrate that ηm values necessitate ηd = 0.2, a relatively substantial value that cannot be disregarded. Additionally, applying the Förster theory for dipole-dipole electric ET, we calculate microparameters for ET between monomers (CDD) and monomer-dimer (CDA). Critical ranges for ET in each case are quantified. Microparameter analysis indicates that ET between monomer-monomer and monomer-dimer species of R-6G dissolved in distilled water holds significance, particularly in determining ηm. These results bear significance, especially in scenarios involving high dye concentrations. While applicable to R-6G in water, similar assessments in other media featuring aggregates are encouraged.

Modeling population and thermal lenses in the presence of Auger Upconversion for Nd(3+) doped materials

We present a theoretical model to thermal (TL) and population (PL) lenses effects in the presence of Auger upconversion (AU) for analysis of Nd(3+) doped materials. The model distinguishes and quantifies the contributions from TL and PL. From the experimental and theoretical results, the AU cannot be neglected because it plays an important role on the excited state population and therefore on the temperature and polarizability difference between excited and ground states. Considering the extensive use of these techniques, the model presented here could be useful for the investigation of materials and also to avoid misleading analysis of lenses transients.

Femtosecond-laser-written, stress-induced Nd:YVO4 waveguides preserving fluorescence and Raman gain

We report the formation of optical waveguides in the self-Raman Nd:YVO(4) laser crystal by femtosecond laser inscription. The confocal fluorescence and Raman images have revealed that the waveguide is constituted by a locally compressed area in which the original fluorescence and Raman gains of the Nd:YVO(4) system are preserved. Thus the obtained structures emerge as promising candidates for highly efficient self-Raman integrated laser sources.

Thermally resistant waveguides fabricated in Nd:YAG ceramics by crossing femtosecond damage filaments

We report on femtosecond laser writing of channel waveguides in Nd(3+) ion doped YAG ceramics by multiple inscriptions of damage filaments. Waveguiding between filaments was found to resist annealing temperatures as high as 1500 degrees C. Microluminescence imaging experiments have been carried out to elucidate the potential application of the obtained waveguides as integrated laser sources as well as to elucidate the waveguiding mechanisms.