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    Algal organic matter fluorescence analysis of Chlorella sp. for biomass estimation
    Cadondon, Jumar; Lesidan, James Roy; Bulan, Jejomar; Vallar, Edgar; Shiina, Tatsuo; Galvez, Maria Cecilia (Multidisciplinary Digital Publishing Institute (MDPI), 2023-11-15)
    Algal Organic Matter (AOM) is derived from the dissolved organic matter composition of the algal species being observed. In this study, excitation–emission fluorescence spectroscopy was used to determine Chlorella sp.’s AOM and pigment characteristics in varying algal biomass concentrations. The AOM and pigment characteristics were observed at 400–600 nm and 600–800 nm fluorescence emission, respectively, with an excitation spectrum of 300–450 nm. F450/680 was computed based on the ratio between the dissolved organic matter contribution at 450 nm and chlorophyll-a at 680 nm. F450/680 positively correlated with algal biomass (r = 0.96) at an excitation wavelength of 405 nm. This study is a good reference for those interested in algal biomass estimation and production in natural waters.
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    Structural, electronic, and optical properties of copper doped monolayer molybdenum disulfide: A density functional theory study
    Ducut, Melsa Rose D.; Rojas, Kurt Irvin M.; Bautista, Reilly V.; Arboleda, Nelson B. Jr. (Elsevier, 2025)
    We conducted first-principles calculations to investigate the effect of doping monolayer molybdenum disulfide (MoS2) with Cu in its structural, electronic, and optical properties. We found that Cu doping changes the material from an n-type semiconductor into a p-type semiconductor by shifting the Fermi energy level towards the valence band in all variations of concentration and site. The absorption coefficient, photoconductivity, and reflectivity calculations indicate that Cu-doped MoS2 is sensitive to violet light. In addition, Cu doping elevates the sensitivity of the material to low-energy light. These results show that Cu-doped MoS2 can be used in optoelectronic applications.