BACKGROUND AND OBJECTIVES Molecular oxygen in the tissue to be treated by photodynamic therapy (PDT) is critical for photodynamic cell killing. The fluence rate of PDT light delivery has been identified as an important modulator of tissue oxygenation and treatment outcome. This article provides supporting evidence for the role of fluence rate in PDT and discusses the underlying mechanisms. ST...

Up-conversion lasing actions are normally difficult to realize in light-emitting materials due small multi-photon absorption cross section and fast dephasing of excited states during excitation. This paper reports an easily accessible up-conversion amplified spontaneous emission (ASE) organic-inorganic hybrid perovskites (MAPbBr3) films by optically exciting broad gap with sub-bandga...

We have demonstrated that the external quantum efficiency (EQE) of organic photovoltaic cells with a heterojunction zinc phthalocyanine (ZnPc) and fullerene (C60) bilayer films, which are used as donor an acceptor, respectively, is improved by photopolymerization (photon energy: 2–4 eV light fluence: 0.4 W cm−2) between adjacent C60 molecules via [2 + 2] cycloadditional four-membered ring. Comp...

New sources and detectors are allowing scientists to look at matter with finer spatial and temporal resolutions. These experiments can produce data that are a series of severely Poisson limited snap-shots of randomly oriented samples. An extreme case of this is destructive imaging of single particles with an x-ray free-electron laser – many frames are needed for a reconstruction, but there is n...

Photoacoustic imaging (PAI) is a non-invasive and non-ionizing imaging modality that combines the absorption contrast of light with ultrasound resolution. Laser is used to deposit optical energy into a target (i.e., optical fluence). Consequently, the target temperature rises, and then thermal expansion occurs that leads to generating a PA signal. In general, most image reconstruction algorithm...

This research focused on studying how light and endogenous abscisic acid regulate leaf development in Hippuris vulgaris, a species of heterophyllic aquatic plant. Amounts of photosynthetically active radiation greater than 300 micromoles per square meter per second caused submerged H. vulgaris shoots to produce aerial-type leaves. Abscisic acid was not detected in shoots grown under noninducing...

Scattering by interstellar dust grains can produce time variable X-ray halos around gamma-ray bursts (GRB). In particular, an X-ray expanding ring is expected when a short pulse of X-ray radiation is scattered by a narrow layer of dust in our Galaxy. We present a new method to detect and analyze dust scattering expanding rings around gamma-ray bursts, using as an example XMM-Newton data of GRB ...

Nonlinear optical phenomena in semiconductors present several fundamental problems in modern optics that are of great importance for the development of optoelectronic devices. In particular, the details of photo-induced lattice dynamics at early time-scales prior to carrier recombination remain poorly understood. We demonstrate the first integrated measurements of both optical and structural, m...

Laser irradiation parameters, especially the laser fluence and the number of pulses are very important factors affecting microstructures formation and improvement of the surface characteristics in different medical, electronic and the other industrial applications. Information about the fluence domain and the number of pulses for the formation of the structures is very important and determines ...