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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 8 (1995), S. 89-95 
    ISSN: 0897-3806
    Keywords: paraglottic space ; airway anaesthesia ; upper airway ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Superior laryngeal nerve anaesthesia is frequently used to facilitate endotracheal intubation in the awake patient. We have modified the transcutaneous approach to this nerve block to employ a short bevel needle. This improves tactile perception in performing the procedure thus simplifying identification of the correct depth of injection. This study was designed to determine the anatomical basis of superior laryngeal nerve anaesthesia and to estimate the success rate using our modified technique. At autopsy, 20 cadavers had nerve block performed substituting 0.02% methylene blue for local anaesthetic. Dissection was then performed to identify the anatomical structures stained by the simulated local anaesthetic. Additional dissections were performed in formalin-fixed cadavers. We found that the dye was injected into the paraglottic space bounded laterally by the thyrohyoid membrane and thyroid cartilage, medially by the laryngeal submucosa, caudad by the conus elasticus, cephalad by the hyoid bone, and anteriorly and posteriorly by the anterior and posterior thyrohyoid ligaments, respectively. The internal laryngeal nerve, the sensory branch of the superior laryngeal nerve, passed through this compartment and was heavily stained with simulated local anaesthetic. Resistance to the passage of the short bevel needle was provided by the lateral glossoepiglottic fold, not the thyrohyoid membrane as we had expected. Of 40 injections, 39 were deemed successful for a success rate of 97.5%. We conclude that this is a simple and highly successful technique for performing superior laryngeal nerve anaesthesia. © 1995 WiIey-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 393-397 
    ISSN: 1059-910X
    Keywords: Surface charging ; Environmental scanning electron microscopy ; Particles ; Filters ; Air samples ; Conductive coating ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This work provides examples of some of the imaging capabilities of environmental scanning electron microscopy applied to easily charged samples relevant to particle analysis. Environmental SEM (also referred to as high pressure or low vacuum SEM) can address uncoated samples that are known to be difficult to image. Most of these specimens are difficult to image by conventional SEM even when coated with a conductive layer. Another area where environmental SEM is particularly applicable is for specimens not compatible with high vacuum, such as volatile specimens. Samples from which images were obtained that otherwise may not have been possible by conventional methods included fly ash particles on an oiled plastic membrane impactor substrate, a one micrometer diameter fiber mounted on the end of a wire, uranium oxide particles embedded in oil-bearing cellulose nitrate, teflon and polycarbonate filter materials with collected air particulate matter, polystryene latex spheres on cellulosic filter paper, polystyrene latex spheres “loosely” sitting on a glass slide, and subsurface tracks in an etched nuclear track-etch detector. Surface charging problems experienced in high vacuum SEMs are virtually eliminated in the low vacuum SEM, extending imaging capabilities to samples previously difficult to use or incompatible with conventional methods. © 1993 Wiley-Liss, Inc.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 18 (1987), S. 339-348 
    ISSN: 0148-7280
    Keywords: B-1,3-glucanase ; cortical granules ; hyaline layer ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The ultrastructural localization of B-1,3-glucanase in three species of sea urchin eggs was determined using a monospecific antibody in an electronmicroscopic immunogold procedure. In all three species, Lytechinus variegatus, Strongylocentrotus purpuratus, and Arbacia punctulata, B-1,3-glucanase was localized specifically to the cortical granules. No other organelle within the egg contained significant label. During the fertilization reaction, B-1,3-glucanase was released from cortical granules into the perivitelline space and became associated with the hyaline layer. No significant label was found in association with the fertilization envelope.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 10 (1989), S. 16-19 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Atrial natriuretic peptides appear to elicit their actions in some target tissues by binding to a novel cell-surface transmembrane protein which possesses both peptide binding and guanylate cyclase activities. Ligand binding stimulates enzyme activity to produce increased intracellular concentrations of cyclic GMP which, in turn, mediates the cell's physiological response.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Als Höhepunkte auf dem Gebiet der Organoelementchemie der schwereren Elemente der vierten Hauptgruppe (Gruppe 14 des Periodensystems) in den 80er Jahren gelten die Darstellung und vollständige Charakterisierung dreier Verbindungsklassen, deren Existenz bis dahin aufgrund ihrer Reaktivität für nicht möglich gehalten wurde. Hierbei handelt es sich um 1) die dreigliedrigen Ringsysteme Cyclotrisilan, -trigerman und -tristannan, 2) Moleküle mit Element-Element-Doppelbindungen einschließlich Disilen, Digermen und Distannen sowie 3) gespannte Polycyclen mit einem Gerüst aus den schwereren Elementen der 4. Hauptgruppe, z. B. Bicyclo[1.1.0]tetrasilan, Hexagermaprisman und Octasilacuban. Die meisten dieser Verbindungen sind durch sperrige Substituenten stabilisiert. Die Verbindungen ermöglichten Untersuchungen über die Veränderungen physikalischer und chemischer Eigenschaften in Abhängigkeit vom Element und den Substituenten sowie über die thermische und photochemische Reaktivität dieser Systeme, wobei zweiwertige Carben-Analoga nachgewiesen wurden. Parallel zu den experimentellen Arbeiten wurden an nahezu allen im Beitrag diskutierten Stammverbindungen Rechnungen durchgeführt. Einige Polycyclen weisen den Weg zu Verbindungen mit einer Element-Element-Dreifachbindung.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diese Übersicht stellt neuere experimentelle Ergebnisse der Erforschung der unendlichen Geschichte der Vitamin-B12-Biosynthese vor, wobei hauptsächlich auf Arbeiten aus der Arbeitsgruppe des Autors zurückgegriffen wird. Darüber hinaus gibt sie einen persönlichen Ausblick auf die Zukunft der Naturstoff-Biosyntheseforschung. Von zentraler Bedeutung ist mittlerweile die leistungsfähige Kombination von molekularbiologischen und modernsten spektroskopischen Techniken. Jene dienen der Suche nach und der Expression von Genen, die für die Enzyme der Biosynthese codieren, diese machen die biochemischen Vorgänge im NMR-Röhrchen direkt beobachtbar. Als logische Weiterentwicklung dieser Ansätze wird die Durchführbarkeit der Eintopf-Multienzymsynthese von Naturstoffen vorgestellt. Dank der Entwicklung und Nutzung von Klonierungstechniken und der daraus resultierenden Verfügbarkeit von Enzymen für die C-C-Verknüpfung hat sich ein grundlegender Wandel im “Handwerkszeug“ des Bioorganikers vollzogen. Gleichzeitig seien aber auch die Organiker angesprochen, die sich diesen technischen Fortschritt zunutze machen wollen. Ihnen wird sich eine neue Welt natürlicher Katalysatoren erschließen, die Synthesen mit hohen Ausbeuten bei einem oftmals überraschenden, aber durchaus willkommenen Mangel an Substratspezifität versprechen. Und schließlich hoffen wir, unsere Begeisterung für diese modernen Methoden weiterzugeben, mit denen heutige wie auch künftige Generationen von Chemikern die Synthesewege der Natur zu komplexen Naturstoffen erforschen können.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 19 (1997), S. 281-284 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Genetic analysis of Drosophila has shown that a morphogenetic gradient of the Transforming Growth Factor-β family member dpp patterns the embryonic dorsalventral axis. Molecular and embryological evidence from Xenopus has strongly suggested a similar role for Bmp-4, the dpp homolog, in patterning the dorsalventral axis of chordates. A recent report has now identified mutations in two genes, dino and swirl, that disrupt dorsal-ventral patterning in the zebrafish Danio rerio(1). Characterization of these mutations parallels findings from Drosophila, thus establishing a genetic framework for the analysis of dorsalventral patterning in a vertebrate.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0570-0833
    Keywords: Bond theory ; Tin ; Germanium ; Silicon ; Strained molecules ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The organometallic chemistry of the Group 14 elements E = Si, Ge, Sn in the 1980's is highlighted by the successful construction and characterization of three systems previously thought to be too reactive to exists: (1) three-membered ring compounds including cyclotrisilane, cyclotrigermane, and cyclotristannane, (2) molecules containing E—E double bonds including disilene, digermene, and distannene, and (3) strained polycycles containing a skeleton of Group 14 elements, such as bicyclo[1.1.0]tetrasilane, hexagemaprismane, and octasilacubane. The majority of these numerous compounds now available are fully substituted with bulky ligands to suppress the reactivity intrinsic to the systems. These compounds permit examinations of (1) the variation of physical and chemical properties of a system with these elements and also with the ligands and (2) how two systems are interrelated thermally and photochemically with the intermediacy of the divalent (carbene-like) species. Theoretical calculations on virtually all of the parent compounds discussed in this review are evaluated alongside the experimental results. Some polycycles may constitute a stepping-stone on the way to compounds with a triple bond.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 32 (1993), S. 1223-1243 
    ISSN: 0570-0833
    Keywords: Vitamins ; Natural products ; Biosynthesis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This review contains an account of recent experimental results in the continuing saga of vitamin B12 biosynthesis (largely from the author's laboratory) as well as a personal view of future directions of research in natural product biosynthesis. The emphasis is on the powerful combination of molecular biology in the search for, and the expression of, the genes encoding the biosynthetic enzymes and state-of-the-art spectroscopic techniques, in order to “view” the biochemical events as they take place in the NMR tube. As a logical development of these approaches, the feasibility of one-flask, multienzyme synthesis of natural products is addressed.[Based on a lecture given at the 27th Euchem Conference on Stereochemistry, 26th April to 4th May, 1992. Bürgenstock, Switzerland. A more explicit account of this new field has been given in “Genetically Engineered Synthesis of Complex Natural Products” (A. I. Scott Terruhedron, 1992, 48, 2559).] Implicit throughout is the profound change in the “tools of the trade” of the bioorganic chemist, thanks to the harnessing and exploitation of cloning techniques and the resultant availability of enzymes which can make carbon-carbon bonds. It is also our desire to alert organic chemists, who may wish to take advantage of these technical developments, to the fact that they will be rewarded by a new world of natural catalysts capable of high yielding, synthetic chemistry often with a surprising, but welcome, lack of substrate specificity. Finally we hope to convey our enthusiasm for the methods now at the disposal of present and future generations of chemists for studying Nature's synthetic routes to complex natural products.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Hoboken, NJ [u.a.] : Wiley-Blackwell
    Journal of Orthopaedic Research 3 (1985), S. 160-169 
    ISSN: 0736-0266
    Keywords: Matrix vesicles ; Cartilage ; Calcification ; Matrix vesicle enzymes ; Osteoarthritis ; Life and Medical Sciences
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The enzymatic activities and in vitro calcification properties of matrix vesicle fractions isolated from normal and osteoarthritic (OA) human articular cartilage were compared to determine the essential conditions for calcification in these tissues. Four groups of human cartilage were examined, I, normal articular cartilage from aged, nonOA joints; II, discolored or fibrillated cartilage from OA joints; III, osteophytic cartilage from OA joints; IV, loose body cartilage from OA joints. Fetal bovine growth plate cartilage was also studied. Both ATP- and 5′-AMP-dependent in vitro matrix vesicle calcification occurs in all cartilage groups examined and, for human articular cartilage, these activities increase progressively from Groups I to II to III. Calcification does not occur in the absence of either phosphate or pyrophosphate. Alkaline phosphatase, 5′-AMPase, and ATP:pyrophosphohydrolase activities are increased in Groups III and IV cartilage compared with Group I and are detected at high levels in fetal bovine growth plate cartilage. Pyrophosphatase activity occurs in only those cartilage groups juxtaposed to areas of new bone formation (osteophytic, loose body, and bovine growth plate). These results suggest that OA, growth plate, and even normal articular cartilage all have the potential to undergo calcification as long as both phosphate and pyrophosphate ions can be generated at sufficiently high levels. However, the capacity for cartilage to deposit hydroxyapatite, as it does during bone formation, may depend on the presence of pyrophosphatase activity.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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