نتایج جستجو برای: alder
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We explored possible interactions among gray wolves (Canis lupus), Rocky Mountain elk (Cervus elaphus), and thinleaf alder (Alnus incana spp. tenuifoli) in northern Yellowstone National Park. We developed an alder age structure based on annual growth rings for plants growing along six streams in areas accessible to ungulates on the northern range. Alder stems (n = 412) along the six streams ori...
Description of the Dry Alder Complex Sitka alder (Alnus viridis ssp. sinuata) is the dominant species of the Dry Alder Complex, and willow (Salix spp.) is also present on some sites (Figure ). Characteristic understorey species are fireweed (Epilobium angustifolium) on sites mesic and wetter, and pinegrass (Calamagrostis rubescens) on sites drier than mesic (Kimmins and Comeau ). Thimbleb...
Nature's repertoire of biosynthetic transformations has recently been recognized to include the Diels-Alder cycloaddition reaction. Evidence now exists that there are enzymes that mediate the Diels-Alder reaction in secondary metabolic biosynthetic pathways. 2002 marked the 100th anniversary of Alder's birth and 75 years since the discovery of the Diels-Alder reaction. It would appear that livi...
Detailed analysis of calculated data from an experimental/computational study of intramolecular furan Diels-Alder reactions has led to the unusual discovery that the mean contraction of the newly forming C-C σ-bonds from the transition state to the product shows a linear correlation with both reaction Gibbs free energies and reverse energy barriers. There is evidence for a similar correlation i...
the aim of this study is comparison of soil characteristics and biodiversity in plantation of bald cypress and caucasian alder forest stands in kludeh region (mazandaran province). in order to study biodiversity in forest stands and control region, 10 sample plots (releve) were selected and the name and abundance of plant species of the forest floor were recorded. biodiversity of herbal plants ...
In this study, we explore the potential to reconstruct lake-level (and groundwater) fluctuations from tree-ring chronologies of black alder (Alnus glutinosa L.) for three study lakes in the Mecklenburg Lake District, northeastern Germany. As gauging records for lakes in this region are generally short, long-term reconstructions of lake-level fluctuations could provide valuable information on pa...
A fascinating aspect of the Diels–Alder reaction is its endo selectivity. This endo preference is much less pronounced in intermolecular cases compared with the intramolecular and transannular Diels–Alder (IMDA and TADA) reactions. Nevertheless, high endo selectivity is observed in the Diels– Alder additions of (E)-1-O-substituted dienes catalyzed by Lewis acids that lead to cis-1,6-disubstitut...
Consultant Gynaecologist, Department of Paediatric Surgery, Alder Hey Children’s Hospital, Liverpool and Liverpool Women’s Hospital, Liverpool, UK Specialist Registrar, Department of Obstetrics and Gynaecology, Liverpool Women’s Hospital, Liverpool, UK Biomedical Scientist, Department of Biochemistry, Alder Hey Children’s Hospital, Liverpool, UK Consultant Gynaecologist, Department of Gynaecolo...
This review is an endeavor to highlight the progress in the inverse-electron-demand hetero-Diels-Alder reactions of 1-oxa-1,3-butadienes in recent years. The huge number of examples of 1-oxadienes cycloadditions found in the literature clearly demonstrates the incessant importance of this transformation in pyran ring synthesis. This type of reaction is today one of the most important methods fo...
Many isoprenylated flavonoids have been isolated from Japanese mulberry tree (Moraceae). Among them, kuwanons G (1) and H (2) were the first isolated active substances exhibiting a hypotensive effect. These compounds are considered to be formed through an enzymatic Diels-Alder type reaction between an isoprenyl portion of an isoprenylphenol as the diene and an alpha, beta-double bond of chalcon...
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