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  • *Light  (2)
  • Burkard sporetrap  (2)
  • Inorganic Chemistry  (2)
  • 1995-1999  (6)
  • 1
    ISSN: 1573-3025
    Schlagwort(e): Aerobiology ; Methodology ; Sampling error ; Burkard sporetrap
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two years of data from four longitudinal traverses along each day's slide prepared from a continuously running Burkard sporetrap have been analyzed statistically. Using the Friedman test, a statistically significant difference was found between the four traverses, with a greater than 7% loss of pollen grains in the two outer traverses in relation to the inner. Four slides were then selected for more detailed analysis, using 18 longitudinal traverses with a 1-mm separation from the upper to the lower edge of the Melinex tape. There was found to be a progressive decline from the centre to the outside, and more than 4% of pollen grains were found outside the typical 14 mm width of the impaction orifice. There was no correlation between pollen grain size and the decline in counts from the centre to the outside. For the complete data set, there was a general rise in the diversity of bollen types with increasing sample counts, but above about 1000 pollen grains per sample there were no more than 27 pollen types found, often even fewer. A discussion is presented of whether four traverses really should be a fixing sample size, or whether it might be better to fix the total pollen count beginning with a traverse in the middle of the slide and ending with a variable number of traverses when that count is reached.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1573-3025
    Schlagwort(e): Aerobiology ; Methodology ; Sampling error ; Burkard sporetrap
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two years of data from four longitudinal traverses along each day's slide prepared from a continuously running Burkard sporetrap have been analyzed statistically. Using the Friedman test, a statistically significant difference was found between the four traverses, with a greater than 7% loss of pollen grains in the two outer traverses in relation to the inner. Four slides were then selected for more detailed analysis, using 18 longitudinal traverses with a 1-mm separation from the upper to the lower edge of the Melinex tape. There was found to be a progressive decline from the centre to the outside, and more than 4% of pollen grains were found outside the typical 14 mm width of the impaction orifice. There was no correlation between pollen grain size and the decline in counts from the centre to the outside. For the complete data set, there was a general rise in the diversity of pollen types with increasing sample counts, but above about 1000 pollen grains per sample there were no more than 27 pollen types found, often even fewer. A discussion is presented of whether four traverses really should be a fixing sample size, or whether it might be better to fix the total pollen count beginning with a traverse in the middle of the slide and ending with a variable number of traverses when that count is reached.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 0044-2313
    Schlagwort(e): Stibocanes ; conformational analysis ; x-ray structures ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Die Beziehung zwischen starker transannularer sekundärer Bindung und Konformation in Diphenyldithiophosphinatstibocanen X(CH2CH2S)2SbS2PPh2 (X = O, S)Die beiden Stibocane 1-Oxa-4,6-dithia-5-stibocan-diphenyldithiophosphinat O(CH2CH2S)2SbS2PPh2 1 und 1,3,6-Trithia-2-stibocan-diphenyldithiophosphinat S(CH2CH2S)2SbS2PPh2 2 wurden aus den entsprechenden Chloro-oxa- und -thia-stibocanen 3 und 6 sowie dem Ammoniumsalz der Diphenyldithiophosphinsäure in CH2Cl2 dargestellt. 1 und 2 wurden durch IR, EI-MS und Multikern-NMR-(1H, 13C, 31P{1H}) Spektren charakterisiert. Die Kristallstruktur von 1 zeigt zwei Sb1 ⃛ S1 intermolekulare Wechselwirkungen [3.987(2) Å] so daß sich ein dimeres Molekül ergibt sowie eine endocyclische, transannulare Sb1 ⃛ O1 [2.555(6) Å] und eine exocyclische Sb1 ⃛ S4 sekundäre Wechselwirkung [3.327(2) Å]. Die Koordination am Antimon kann als AX4YE ψ-trigonal bipyramidale Geometrie beschrieben werden, mit A = Sb, X = S1, S2, S3, O1; Y = S4. S1, S2 und das freie Elektronenpaar liegen in der äquatorialen Ebene, O1 und S3 besetzen die axialen Positionen. Die sekundäre Bindung Sb1 ⃛ S4 liegt über einer Ebene, die von dem freien Elektronenpaar der trigonalen Bipyramide, S2 und S3 gebildet wird. Molekül 2 zeigt ebenfalls eine endocyclische, transannulare Sb1 ⃛ S2 [2.949(3) Å] und eine exocyclische Sb1 ⃛ S5 sekundäre Wechselwirkung [3.216(3) Å]. Antimon ist hier ebenfalls fünffach koordiniert, wodurch sich eine AX4YE ψ-trigonale bipyramidale Geometrie ergibt, mit S1, S3 und dem freien Elektronenpaar in der äquatorialen Ebene und mit S2 und S4 in den axialen Positionen. Die sekundäre Bindung Sb1 ⃛ S5 liegt auch hier über einer Ebene, die von dem freien Elektronenpaar der trigonalen Bipyramide, S3 und S4 gebildet wird.
    Notizen: The two stibocanes 1-oxa-4,6-dithia-5-stibocane diphenyldithiophosphinate O(CH2CH2S)2SbS2PPh2 1 and 1,3,6-trithia-2-stibocane diphenyldithiophosphinate S(CH2CH2S)2 · SbS2PPh2 2 were prepared from the corresponding chloro oxa- and thia-stibocanes 3 and 6, and the ammonium salt of diphenyldithiophosphinic acid in CH2Cl2. 1 and 2 were characterized by IR, EI-MS and multinuclear NMR (1H, 13C, 31P{1H}). The crystalline state of 1 features two Sb1 ⃛ S1 intermolecular interactions [3.987(2) Å] that results in a dimer. Alongside 1 displays both an endocyclic, transannular Sb1 ⃛ O1 interaction [2.555(6) Å] and an exocyclic Sb1 ⃛ S4 secondary interaction [3.327(2) Å]. The coordination geometry at the antimony could be described as AX4YE ψ-trigonal bipyramid geometry with A = Sb, X = S1, S2, S3,O1; Y = S4; S1, S2 and the lone pair lays on the equatorial plane with O1 and S4 in axial positions. The Sb1 ⃛ S4 secondary bonding is face capping one of the planes form by the lone pair, S2 and S3 of the trigonal bipyramid. 2 also displays both an endocyclic, transannular Sb1 ⃛ S2 interaction [2.949(3) Å] and an exocyclic Sb1 ⃛ S5 secondary interaction [3.216(3) Å]. The antimony becomes five-coordinate, giving the AX4YE ψ-trigonal bipyramid geometry with S1, S3 and the lone pair laying on the equatorial plane with S2 and S4 in axial positions. The Sb1 ⃛ S5 also here is face capping the plane form by the lone pair, S3 and S4 of the trigonal bipyramid.The conformation of the eight membered ring in 2 is boat-chair. In 1 the main conformation is chair-planar.Die Konformation des Achtringes in 2 ist Wanne-Sessel. In 1 ist die Konformation des Achtringes Sessel-planar.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 0044-2313
    Schlagwort(e): Stibocanes ; dithiophosphinates ; conformational analysis ; x-ray structures ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Konformative Trends und intermolekulare Assoziation in Dialkyldithiophosphinat-Stibocanen X(CH2CH2S)2SbS2PR2 (X = O, S; R = Me, Et)Alkylstibocanes O/S(CH2CH2S) 2SbS2PMe2/ Et2 1-4 wurden aus den entsprechenden Chlorooxa- und -thiastibocanen bzw. Natriumdialkyldithiophosphinaten in CH2Cl2 dargestellt und durch IR, EI-MS und Multikern-NMR (1H, 13C, 31P{1H}) charakterisiert. Die Kristall- und Molekülstrukturen von O(CH2CH2S) 2SbS2PMe2 1 und S(CH2CH2S) 2PMe2 3 wurden bestimmt. Die Kristallstruktur von 1 zeigt ein Dimer durch zwei Sb … S-intermolekulare Wechselwirkungen (3,960(3) Å). 3 bildet im kristallinen Zustand eine dimere Struktur durch eine sekundäre Sb … Sb-Bindung (4,067(1) Å), 1 und 3 zeigen endocyclische, transannulare Sb … O/S-Wechselwirkungen (1: 2,561(7) Å; 3: 2,972(1) Å) und exocyclische, sekundäre Sb … S-Bindungen (1: 3,454(2) Å; 3: 3,147(2) Å). Die Strukturen von 1 und 3 können als trigonal bipyramidal beschrieben werden mit zusätzlichen sekundären Kontakten über eine Ebene bzw. Kantenverbrückt. Die Konformation des Achtrings in 3 ist Wanne-Sessel, die in 1 Sessel-planar.
    Notizen: The alkyl stibocanes O/S(CH2CH2S)2SbS2PMe2/ Et2 1-4 were prepared from the corresponding chloro oxa and thiastibocanes, and sodium dialkyldithiophosphinates in CH2Cl2. Compounds 1-4 were characterized by IR, EI-MS and multinuclear NMR (1H, 13C, 31P{1H}). The crystal and molecular structures of O(CH2CH2S)2SbS2PMe2 1 and S(CH2CH2S)2SbS2PMe2 3 were determined. The crystalline state of 1 has two Sb … S intermolecular interactions [3.960(3) Å] that results in a dimer. The crystalline state of 3 features a dimeric structure through an Sb … Sb secondary bonding [4.067(1) Å]. Compounds 1 and 3 display both an endocyclic, transannular Sb … O/S interaction [1, 2.561(7) Å; 3 2.972(1) Å] and an exocyclic Sb … S secondary bonding [1, 3.454(2) Å, 3, 3.147(2) Å]. The coordination geometry in 1 and 3 could be described as trigonal bipyramidal with additional secondary bonding contacts face capping or edge bridging the polyhedron. The conformation of the eight membered ring in 3 is boat-chair. Whereas in 1, the mean conformation is chair-planar.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 1999-04-16
    Beschreibung: In mammals, ocular photoreceptors mediate an acute inhibition of pineal melatonin by light. The effect of rod and cone loss on this response was assessed by combining the rd mutation with a transgenic ablation of cones (cl) to produce mice lacking both photoreceptor classes. Despite the loss of all known retinal photoreceptors, rd/rd cl mice showed normal suppression of pineal melatonin in response to monochromatic light of wavelength 509 nanometers. These data indicate that mammals have additional ocular photoreceptors that they use in the regulation of temporal physiology.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lucas, R J -- Freedman, M S -- Munoz, M -- Garcia-Fernandez, J M -- Foster, R G -- New York, N.Y. -- Science. 1999 Apr 16;284(5413):505-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Sir Alexander Fleming Building, Imperial College of Science, Technology and Medicine, London, SW7 2AZ, UK. r.j.lucas@ic.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10205062" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Biological Clocks/physiology ; Circadian Rhythm/*physiology ; Cryptochromes ; Darkness ; *Drosophila Proteins ; *Eye Proteins ; Flavoproteins/genetics/physiology ; *Light ; Light Signal Transduction ; Melatonin/*metabolism ; Mice ; Mice, Inbred C3H ; Mice, Transgenic ; *Photoreceptor Cells, Invertebrate ; Photoreceptor Cells, Vertebrate/*physiology ; Pineal Gland/*metabolism ; Receptors, G-Protein-Coupled ; Retina/cytology/*physiology ; Retinal Ganglion Cells/physiology ; Retinal Pigments/genetics/physiology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 1999-04-16
    Beschreibung: Circadian rhythms of mammals are entrained by light to follow the daily solar cycle (photoentrainment). To determine whether retinal rods and cones are required for this response, the effects of light on the regulation of circadian wheel-running behavior were examined in mice lacking these photoreceptors. Mice without cones (cl) or without both rods and cones (rdta/cl) showed unattenuated phase-shifting responses to light. Removal of the eyes abolishes this behavior. Thus, neither rods nor cones are required for photoentrainment, and the murine eye contains additional photoreceptors that regulate the circadian clock.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Freedman, M S -- Lucas, R J -- Soni, B -- von Schantz, M -- Munoz, M -- David-Gray, Z -- Foster, R -- New York, N.Y. -- Science. 1999 Apr 16;284(5413):502-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, Alexander Fleming Building, Imperial College of Science, Technology and Medicine, London, SW7 2AZ, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10205061" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Biological Clocks/*physiology ; Circadian Rhythm/*physiology ; *Light ; Mice ; Mice, Transgenic ; Motor Activity ; *Ocular Physiological Phenomena ; Photoreceptor Cells, Vertebrate/*physiology ; Pigments, Biological/physiology ; Retinal Cone Photoreceptor Cells/physiology ; Retinal Pigments/physiology ; Retinal Rod Photoreceptor Cells/physiology
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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