A review of photodiagnostic investigations over 26 years: experience of the National Scottish Photobiology Service (1989-2015).

Background The Scottish Photobiology Service is the national referral pathway for patients with cutaneous photosensitivity diseases in Scotland. We reviewed the pattern of diagnosis of photosensitivity diseases and investigations performed between 1989 and 2015. Methods and Results Data were collected from the Photodiagnostic Database, annual reports and paper records. The total number of patients assessed each year was stable over the period studied (median 242 [range 231-266]), with most being new patients (median 69 [range 62-73]%). Monochromator phototesting was the most utilised investigation, although the use of provocation testing and photopatch testing has increased. The most common diagnosis was polymorphic light eruption, and there was a trend to increasing diagnosis of photoaggravated atopic eczema. Conclusions The pattern of diagnosis of photosensitivity diseases remains fairly stable in Scotland and we wish to emphasise the importance of this Scottish specialist service for patients with photosensitivity diseases and referrers.

Metodologia para germinação de sementes de Leonurus sibiricus L / Methodology for Leonurus sibiricus L. seed germination

O objetivo do trabalho foi investigar a influência de diferentes temperaturas, o comportamento fotoblástico e a absorção de água de sementes de Leonurus sibiricus L. Essa espécie medicinal é originária da Índia, distribuída pela Ásia, África e América, utilizada no tratamento de reumatismo, problemas dermatológicos e respiratórios. Para tanto, as sementes foram submetidas a temperaturas entre 5 a 40ºC, com intervalos de 5ºC, e alternadas de 20/30, 20/25 e 25/30ºC, com 5 repetições de 50 sementes cada, em condições de luz e escuro. No estudo da absorção de água as sementes foram colocadas para germinar na temperatura de 20ºC e na presença da luz e pesadas para avaliar o ganho de água durante todo o processo germinativo, até a protrusão da radícula. Pelos resultados verificou-se que os maiores porcentuais de germinação e índice de velocidade de germinação ocorreram na temperatura constante de 20ºC, e nas temperaturas alternadas 20/25, 25/30, 25/30ºC sob luz. Houve germinação na temperatura mínima de 10ºC e na máxima 40ºC. No ensaio de absorção de água verificou-se que as sementes iniciam a protrusão da radícula com 65 horas de exposição e seguem padrão trifásico na curva de absorção. O modelo estatístico ajustado para a espécie foi y = 1,869 (1 - 0,414 exp ( -0,201t) + exp [-2,397 + 0,037 (t - 65)], com R²= 0,9998.

The aim of this study was to investigate the influence of different temperatures on the photoblastic response and water uptake of Leonurus sibiricus L. seeds. This medicinal species is from India and has been distributed over Asia, Africa and America, where it is used in the treatment of rheumatic, dermatological and respiratory disorders. Thus, seeds were subjected to temperatures between 5 and 40ºC, at 5ºC intervals, and 20/30, 20/25 and 25/30ºC alternate temperatures, with five replicates of 50 seeds each, under light and dark conditions. In the study of water uptake, seeds were allowed to germinate at 20ºC under light and weighed throughout the germinative process until radicle protrusion. The highest germination percentage and speed index were detected at 20ºC constant temperature and at 20/25, 25/30 and 25/30ºC alternate temperatures under light. There was germination at 10ºC (minimum temperature) and at 40ºC (maximum temperature). The study on water uptake showed that seeds began radicle protrusion at 65h exposure and follow the triphasic pattern in the uptake curve. The statistical model fit for the species was y = 1.869 (1 - 0.414 exp (-0.201 t) + exp [-2.397 + 0.037 (t - 65)], R² = 0.9998.

Light transport in tissue by 3D Monte Carlo: influence of boundary voxelization.

Monte Carlo (MC) based simulations of photon transport in living tissues have become the "gold standard" technique in biomedical optics. Three-dimensional (3D) voxel-based images are the natural way to represent human (and animal) tissues. It is generally believed that the combination of 3D images and MC based algorithms allows one to produce the most realistic models of photon propagation. In the present work, it is shown that this approach may lead to large errors in the MC data due to the "roughness" of the geometrical boundaries generated by the presence of the voxels. In particular, the computed intensity of the light detected on the tissue surface of a simple cubic tissue phantom may display errors from -80% to 120%. It is also shown that these errors depend in a complex manner on optical and geometrical parameters such as the interoptode distance, scattering coefficient, refractive index, etc. and on the degree of voxelization ("roughness") of the boundaries. It is concluded that if one wants to perform reliable 3D Monte Carlo simulations on complex geometries, such as human brain, skin or trabecular bone, it is necessary to introduce boundary meshing techniques or other equivalent procedures in the MC code to eliminate the deleterious effect of voxelization.

Radiometric quantities and units used in photobiology and photochemistry: recommendations of the Commission Internationale de L'Eclairage (International Commission on Illumination).

To characterize photobiological and photochemical phenomena, standardized terms and units are required. Without a uniform set of descriptors, much of the scientific value of publications can be lost. Attempting to achieve an international consensus for a common language has always been difficult, but now with truly international scientific publications, it is all the more important. As photobiology and photochemistry both represent the fusion of several scientific disciplines, it is not surprising that the physical terms used to describe exposures and dosimetric concepts can vary from author to author. There are, however, international organizations that were established to minimize the confusion produced by poor or inconsistent technical terminology. This note is to review the standardized terms and provide a background on how such terms are developed, with the hope that all readers will attempt to follow the standardized terminology.