A method based on fluorescence lifetime distribution analysis is proposed for the determination of micellar size distributions in polydisperse systems. The exponential series method is employed to determine the lifetime distribution for a probe in the presence of quencher. This distribution is then analyzed by the maximum entropy method in order to recover the size distribution function. The method has been tested on sodium dodecyl sulfate and cetyltrimethylammonium chloride micellar systems in the presence and absence of added salt. Excellent agreement is obtained with other methods of size determination in cases where it is reasonable to make such comparisons. In both systems, the addition of salt is observed to bring about first a shift in the averageaggregation number to approximately double the zero salt value and then the development of a bimodal distribution. This latter phenomenon is interpreted as a transitional phase between spherical and rod-shaped micelles.

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The ill-conditioned nature of the lifetime distribution analysis is demonstrated using the fluorescence decay data of pyrene adsorbed on variously dehydroxylated silica gel surfaces. A set of physically plausible results can be obtained only after a regularization technique is employed in the data reduction. This study indicates that a bimodal distribution appears to be suitable for describing the lifetime of pyrene adsorbed on a silica gel surface.

In a lifetime distribution analysis of six polycyclic aromatic hydrocarbons (PAHs) adsorbed on silica gel surfaces, a dramatic photophysical effect on the surface can be seen in the PAHs where the lowest excited singlet state is of 'Lb type. This suggests that this effect is related to the symmetry of the lowest excited singlet state of the particular molecule. In addition, a comparison of the photophysical behavior of these PAHs adsorbed on a highly dehydroxylated and on a hydroxylated silica gel surface suggests that the natures of these two types of adsorption may be different. These results show that the regularized lifetime distribution analysis is a useful tool in the surface photophysical studies. Introductioo

The genus Amanita, comprising three subgenera and eleven sections, is one of the most species diverse genera within the class Agaricomycetes. To date, 54 species have been validly reported from Thailand. During surveys of macro-fungi in northern Thailand in 2019 and 2020, three Amanita species were collected and identified as the members of Amanita sect. Lepidella based on morphological and molecular data. Among the three species, two species were identified as A. aureofloccosa and A. manicata and A. aureofloccosa is reported as a new record in Thailand. Interestingly, the third species was distinct from all other known species within sect. Lepidella. We describe the third species as a new species, namely A. albicarnosa. All these three taxa are documented with morphological characteristics, a phylogenetic tree, line drawings, color photographs, and comparisons with morphologically similar taxa. A distributional map of the sampling sites and a key to the Thai species of Amanita sect. Lepidella are also provided.