Photoselective-Light Impacts on Fruit Bagging Microclimate, Quality, and Nutrients of Peach

The use of paper or nylon bags (fruit bagging) to surround tree fruit during development provides protection from a variety of pest-disease complexes for peach without yield reduction and different-colored bags have the potential to improve fruit quality based on findings from other crops. An experiment was conducted in 2019 at two locations in central Florida on peach [Prunus persica (L.) Batch] ‘TropicBeauty’ and ‘UFSun’ to analyze the impact of a commercially available white paper fruit bag combined with a photoselective insert. The insert reduced the amount of light outside the spectrum range of interest for blue (400–500 nm), green (500–600 nm), or red (>600 nm) wavebands, or decreased fluence rate with a neutral density black (>725 nm) insert. Relative to ambient, temperature inside all bagging treatments during the daytime hours was increased by 5.1 °C. During the same time, relative humidity was reduced by 10.1%, but calculations revealed that the water vapor pressure was elevated only for treatments that had a plastic colored (blue, green, or red) insert. An orthogonal contrast revealed that the elevated water vapor around the fruit in a colored bag increased the concentration of chlorophyll at harvest but had no effect on other quality parameters. Compared with unbagged fruit, red-bagged fruit were 1.8 times firmer and green-bagged fruit and had a lower peel chroma. White-bagged (without photoselective insert) fruit had similar nutrient concentrations for the peel, flesh, and pit when compared with unbagged fruit. When bags remained on the fruit until harvest, anthocyanin concentration in unbagged fruit peel was double the amount in white bags and 6-fold more than the bags with color inserts. Different-colored bagging treatments did not influence insect attraction or fruit quality parameters, such as fruit size, diameter, difference of absorbance (DA) index, total soluble solids (TSS), titratable acidity (TA), pH, peel lightness, peel hue, flesh lightness, flesh hue, or flesh chroma. Relative to full sun, the colored bag treatments allowed between 3.7% (black) and 17.4% (red) of the photosynthetically active radiation (PAR). Additional research is needed to determine if an increase in fluence rate at specific spectral wavelengths can affect the quality for peach grown in bags in the field.

Optimization of brain photodynamic therapy : a study of extended-time low-fluence-rate ALA-photodynamic therapy in a rat glioma mode

The importance of the rate of light delivery and the length of photodynamic therapy as an alternative treatment modality for brain glioma have been investigated and shown that optimized PDT regimens would have the potential to reduce the tumor recurrence and the treatment-induced morbidity. In a rat glioma model, using photosensitizer ALA-PpIX, we further investigated the effect of extended-time low-fluence-rate PDT on the number of apoptotic, necrotic, surviving, and infiltrated tumor cells, associated with three fluence rates of 0.5, 1.0, and 1.5 mW cm⁻², each at three treatment lengths of 24, 48, and 72 hours. Our results demonstrated that lowest fluence rate used in our study has an improved apoptosis to necrosis ratio; however higher fluence rates show a clear supremacy for tumor control in shorter treatment times. Therefore, low-fluence-rate brain ALA-PDT may only be more beneficial for tumor control at longer treatment periods.

Optimization of brain photodynamic therapy : a study of extended-time low-fluence-rate ALA-photodynamic therapy in a rat glioma mode

The importance of the rate of light delivery and the length of photodynamic therapy as an alternative treatment modality for brain glioma have been investigated and shown that optimized PDT regimens would have the potential to reduce the tumor recurrence and the treatment-induced morbidity. In a rat glioma model, using photosensitizer ALA-PpIX, we further investigated the effect of extended-time low-fluence-rate PDT on the number of apoptotic, necrotic, surviving, and infiltrated tumor cells, associated with three fluence rates of 0.5, 1.0, and 1.5 mW cm⁻², each at three treatment lengths of 24, 48, and 72 hours. Our results demonstrated that lowest fluence rate used in our study has an improved apoptosis to necrosis ratio; however higher fluence rates show a clear supremacy for tumor control in shorter treatment times. Therefore, low-fluence-rate brain ALA-PDT may only be more beneficial for tumor control at longer treatment periods.

Effects of Beam Conditions in Ground Irradiation Tests on Degradation of Photovoltaic Characteristics of Space Solar Cells

We investigated the effects of irradiation beam conditions on the performance degradation of silicon and triple-junction solar cells for use in space. The fluence rates of electron and proton beams were varied. Degradation did not depend on the fluence rate of protons for both cells. A higher fluence rate of electrons caused greater degradation of the Si cell, but the dependence was due to the temperature increase during irradiation. Two beam-area expansion methods, defocusing and scanning, were examined for proton irradiation of various energies (50 keV–10 MeV). In comparing the output degradation from irradiation with defocused and scanned proton beams, no significant difference in degradation was found for any proton energy. We plan to reflect these findings into ISO standard of irradiation test method of space solar cells.