Signal generation in three-photon microscopy is proportional to the inverse-squared of the pulse width. Group velocity dispersion is anomalous for water as well as many glasses near the 1,700 nm excitation window, which makes dispersion compensation using glass prism pairs impractical. We show that the high normal dispersion of a silicon wafer can be conveniently used to compensate the dispersion of a 1,700 nm excitation three-photon microscope. We achieved over a factor of two reduction in pulse width at the sample, which corresponded to over a 4x increase in the generated three-photon signal. This signal increase was demonstrated during in vivo experiments near the surface of the mouse brain as well as 900 μm below the surface.
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http://dx.doi.org/10.1364/BOE.6.001392 | DOI Listing |
Materials (Basel)
January 2025
School of Civil Engineering, Nantong Institute of Technology, Nantong 226000, China.
Adding expansion agents to compensate for concrete shrinkage is a common crack resistance technique, but excessive expansion can also increase the porosity of concrete and reduce its strength. The addition of fibers can reduce expansion and improve the compactness of concrete. However, too little fiber will not be effective in inhibition, while too much fiber will cause aggregation.
View Article and Find Full Text PDFOecologia
January 2025
Tohoku Research Center, Forestry and Forest Products Research Institute, Morioka, Iwate, Japan.
Vertical seed dispersal towards higher or lower altitudes is an important process for plants' adaptation to climate change. Although many plants depend on animals for seed dispersal, studies on vertical seed dispersal by animals, determined by complex animal behaviours, are scarce. Previous studies hypothesised that animals inhabiting temperate regions disperse seeds uphill in spring/summer and downhill in autumn/winter due to their seasonal movement following the altitudinal gradients in food phenology.
View Article and Find Full Text PDFEnviron Res
January 2025
Institute of BioEconomy, National Research Council (CNR), Florence, Italy.
Background: Climate change is a fundamental threat to human health and outdoor workers are one of the most vulnerable population subgroups. Increasing heat stress and heatwaves are directly associated with the health and safety of workers for a large spectrum of occupations. Heat stress negatively affects labour supply, productivity, and workability.
View Article and Find Full Text PDFNat Commun
January 2025
Hunan University of Technology and Business, Changsha, China.
The exposure to extreme heat at workplaces poses substantial threat to human effort and manual labour. This becomes more prominent due to the global dispersion of labour-intensive production activities via trade. We combine a climate model with an input-output model to quantify the risks associated with trade-related occupational extreme heat exposure.
View Article and Find Full Text PDFJ Neurooncol
January 2025
Department of Neurosurgery, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
Purpose: Diffusing alpha-emitters Radiation Therapy ("Alpha DaRT") is a new cancer treatment modality that employs radium-224-loaded metal sources implanted in solid tumors to disperse alpha-emitting atoms within a therapeutic "kill-zone" of a few millimeters around each source. Preclinical studies have demonstrated tumor growth delay in various cancer types, including glioblastoma multiforme, and the method is used in clinical trials for patients with skin and head and neck cancer. This study aims to assess the safety and feasibility of implementing Alpha DaRT for brain tumor treatment in a large animal model.
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