Red light treatment of dark-grown 6-day-old barley seedlings (Hordeum vulgare L.) strongly reduces the lag in chlorophyll accumulation in subsequent white light over that found in dark control seedlings placed under white light. Fluence-response studies show that the effect has both very low fluence and low fluence components. Kinetic studies indicate that the reduction in lag begins immediatel...

We report on the ablation and fabrication of optical waveguide using allyl-diglycol CR39 polymer. Pulse nanosecond (ns) laser (248 nm KrF) and continuous wave (CW) (244 nm argon-ion) irradiation are performed to observe surface modification on the polymer and potentially utilize it for channel waveguide. The pulsed UV laser creates craters with different depth as fluence increases to quantify t...

BACKGROUND To develop a new procedure for laser prostatectomy through a biopsy needle, we evaluated the efficacy of interstitial laser irradiation with a pulsed Ho:YAG laser (lambda: 2.1 microns) in the normal canine prostate. METHODS Pathological studies were performed up to 6 months after interstitial laser irradiation in 26 mongrel dogs (15.4 +/- 2.6 kg). Two dogs underwent the identical p...

Fluence-response relationships of phototropism in light- and dark-grown buckwheat (Fagopyrum esculentum Moench.) were compared using systematically varied fluence rates and irradiation times of unilateral monochromatic blue light. Etiolated seedlings respond to most fluence rates in a tri-phasic manner. Phase one differs from classic first positive in that reciprocity is not observed and the pe...

In this first paper of a two-paper series, we present a method for 10 optimizing the dynamic delivery of fluence maps in radiation therapy. For a given fluence map and a given delivery time, the optimization of the leaf trajectories of a multi-leaf collimator to approximately form the given fluence map is a nonconvex optimization problem. Its general solution has not been addressed in the liter...

Dynamic changes in internal light fluence were measured during interstitial laser heating of tissue phantoms and ex vivo bovine liver. In albumen phantoms, the results demonstrate an unexpected rise in optical power transmitted approximately I cm away from the source during laser exposure at low power (0.5-1 W), and a decrease at higher powers (1.5-2.5 W) due to coagulation and possibly charrin...

Fluence-response curves for the induction of seed germination after 24 hours pretreatment at 35 degrees C of Rumex obtusifolius and Arabidopsis thaliana show two phases of response: (a) a very low fluence-response (10(-4) - 10(-1) micromoles per square meter) and (b) a low fluence-response (1 - 10(3) micromoles per square meter).

This work presents a numerical study of the fluence-resolution behaviour for two coherent lensless X-ray imaging techniques. To this end the fluence-resolution relationship of inline near-field holography and far-field coherent diffractive imaging are compared in numerical experiments. To achieve this, the phase reconstruction is carried out using iterative phase-retrieval algorithms on simulat...

Photodynamic therapy (PDT) of the thoracic cavity can be performed in conjunction with surgery to treat cancers of the lung and its pleura. However, illumination of the cavity results in tissue exposure to a broad range of fluence rates. In a murine model of intrathoracic PDT, we studied the efficacy of 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH; Photochlor(®))-mediated PDT in reduc...

Hypocotyl growth in Cucumis sativus L. cv Ridge Greenline is inhibited by increasing blue light (B) fluence rate in a near log linear fashion once a low fluence threshold is exceeded. Deviation from log linearity at the highest fluence rate used here is due to light perceived by the cotyledons and this effect is assigned to phytochrome. This response can be removed by Norflurazon treatment, wit...