Abstract The shrubby Usnea species of East Fennoscandia and the whole known Usnea flora of British Columbia were studied. Furthermore, the status and distribution of Usnea hirta and U. longissima, which have divergent habitat requirements and distribution patterns, were surveyd in East Fennoscandia. The two species also occur in British Columbia and their chemistry, ecology and distribution were compared in the two study areas. The nomenclature and taxonomy of U. hirta were also revised. Nine shrubby Usnea species were documented from East Fennoscandia and 25 species and species groups were recorded from British Columbia (when U. fulvoreagens and U. pacificana are included as distinct species). U. chaetophora, U. diplotypus and U. nidulans s. lat. were reported as new to North America, whereas U. esperantiana and U. rigida s. lat. were documented for the first time for Canada, and U. ceratina and U. rubicunda are new to British Columbia. U. pacificana was described as a new species from the Pacific Canada and the United States and U. wasmuthii was reported from the states of Washington and Oregon as new to North America. Several taxa were recognized as synonyms and lectotypified in our studies. In total, 21 secondary medullary substances or compound groups were found in the East Fennoscandian and 24 in the British Columbia Usnea species. Salazinic acid is the most common substance in both areas. New chemotypes were found in three shrubby Usnea species in East Fennoscandia and in six taxa in British Columbia. Differences in the chemistry of some species were found when comparing the East Fennoscandian and British Columbia specimens, e.g., in U. hirta and U. longissima. All the East Fennoscandian Usnea species studied have a relatively southern distribution or they are infrequent in northern regions, while most of the surveyed North American species have more or less maritime distribution. All these Usneae are primarily epiphytes and the majority of them prefer well-lit and moist sites.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 97-107). Also available on the World Wide Web.

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This study investigates the effects that lichens have on rock surfaces in which ancient rock art (petroglyphs and pictographs) may be found. The study area includes four sites in the United States: one quartzite site in southwest Minnesota, two sandstone sites in Wyoming, and one volcanic site in Central New Mexico. One additional granitic site studied is located northeast Queensland, Australia. The questions driving the pursuit of this dissertation research are: 1. How does the chemistry of the rock change with weathering and how deep is the profile? 2. Do lichens cause differential chemical changes? 3. How does the chemistry of the unaltered rock influence these changes? 4. Do lichens strip the patina or “desert varnish” from the rock surfaces? The results of this research confirm from elemental chemical analyses that geochemical changes do take place in the presence of lichens. The combined mechanical and chemical processes contribute to the degradation and greater erodability of all the rock surfaces studied. Chemically, we have demonstrated that cements that hold grains of rocks together can be dissoluble by lichen byproducts in the presence of an aqueous environment whether the rocks are sandstone or granite. This information regarding the mechanical and geochemical processes at work in natural environments has significant practical benefit for the management, conservation, and preservation of rock art sites everywhere.

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Thesis--University of Helsinki, 1989. / At head of title: Department of Oral Surgery, Institute of Electron Microscopy, University of Helsinki, and Fourth Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland. Includes bibliographical references (p. 58-71).

INTRODUCTION: Vulvar lichen sclerosus (LS) is characterized by thinning of the epithelium, and whitening of the vulvar skin which can lead to the characteristic symptoms of burning and itching. There is no cure for vulvar LS and topical corticosteroids are first-line treatment. The aims of this thesis are to propose a study to determine whether topical combination therapy with an ultra-potent corticosteroid and calcineurin inhibitor leads to greater improvement in symptoms and clinical appearance of disease than traditional first-line treatment with an ultra-potent corticosteroid alone, and to evaluate relapse rates between the combination therapy group compared to the topical corticosteroid only group. REVIEW OF LITERATURE: The ultra-potent corticosteroid clobetasol propionate is currently the first-line treatment for women with LS however not all patients achieve remission, and many patients have relapses. Topical calcineurin inhibitors such as tacrolimus are considered to be second-line treatments for vulvar LS and may eliminate the side effects of thinning that can occur with long-term therapy with corticosteroids. METHODS: A single-center randomized control trial will be conducted with post-menopausal women recruited from the dermatology and gynecology at Boston Medical Center. The patients will be randomized to either three months treatment with daily clobetasol propionate in the morning and tacrolimus ointment in the evening, or clobestasol propionate in the morning with a vehicle ointment in the evening. The patients will be evaluated for improvement in symptoms of burning and itching, and for clinical appearance of erythema, whitening of the skin, and hyperkeratosis, purpuric lesions and excoriations. The patients will also be followed for a year post-treatment for signs of relapse. CONCLUSION: The incidence of vulvar LS is increasing and may be under-reported. Though corticosteroids are an effective treatment for most patients, combination therapy with topical tacrolimus may increase the proportion of patients who achieve remission for vulvar LS and will improve their quality of life.