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  • Articles  (16)
  • Chemistry  (10)
  • Life and Medical Sciences  (4)
  • Pisces  (2)
  • Fundamental concepts
  • Aircraft Propulsion and Power
  • 1990-1994  (16)
  • 1
    Electronic Resource
    Electronic Resource
    Reproduction in an aggregating grouper, the red hind,epinephelus guttatus (1994)
    Springer
    Environmental biology of fishes 41 (1994), S. 269-286 
    Details
    ISSN: 1573-5133
    Keywords: Spawning ; Serranidae ; Pisces ; Puerto Rico ; Protogyny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis We examined the reproductive pattern of an aggregating grouper, the red hind,Epinephelus guttatus, in Puerto Rico. Macroscopic and histological examination of gonads confirmed that, although mature, ripe ovaries are found over a three-month period, spawning activity is limited to about 2 weeks each year. Females are determinate spawners and individuals are able to spawn more than once during the course of the annual spawning season. The red hind is protogynous and 50% maturity is attained at 215 mm fork length. In western Puerto Rico, spawning occurs in aggregations at several sites within loosely defined areas located towards the edge of the insular platform. Sex ratios of individuals taken by hook and line at one of the aggregation areas over a consecutive six-year period, suggest considerable intra- and inter-annual variation most likely attributable to a combination of differential ingress and egress by males and females during the course of an aggregation and to fluctuations in recruitment, differential mortality by sex and sex change among years. A comparative assessment of the reproductive patterns of seven western AtlanticEpinephelus spp. suggests that aggregation-spawning is associated with medium- to large-sized groupers, while smaller groupers do not aggregate. Mating systems vary among congeners in association with trends in male-female size dimorphism, sexual pattern and sperm competition. The short-term, localized, nature of spawning aggregations renders species with this reproductive mode particularly vulnerable to fishing pressure at spawning sites. Aggregating species, therefore, may require special management consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02197849
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  • 2
    Electronic Resource
    Electronic Resource
    Reproduction in an aggregating grouper, the red hind,epinephelus guttatus (1994)
    Springer
    Environmental biology of fishes 41 (1994), S. 269-286 
    Details
    ISSN: 1573-5133
    Keywords: Spawning ; Serranidae ; Pisces ; Puerto Rico ; Protogyny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis We examined the reproductive pattern of an aggregating grouper, the red hind,Epinephelus guttatus, in Puerto Rico. Macroscopic and histological examination of gonads confirmed that, although mature, ripe ovaries are found over a three-month period, spawning activity is limited to about 2 weeks each year. Females are determinate spawners and individuals are able to spawn more than once during the course of the annual spawning season. The red hind is protogynous and 50% maturity is attained at 215 mm fork length. In western Puerto Rico, spawning occurs in aggregations at several sites within loosely defined areas located towards the edge of the insular platform. Sex ratios of individuals taken by hook and line at one of the aggregation areas over a consecutive six-year period, suggest considerable intra- and inter-annual variation most likely attributable to a combination of differential ingress and egress by males and females during the course of an aggregation and to fluctuations in recruitment, differential mortality by sex and sex change among years. A comparative assessment of the reproductive patterns of seven western AtlanticEpinephelus spp. suggests that aggregation-spawning is associated with medium- to large-sized groupers, while smaller groupers do not aggregate. Mating systems vary among congeners in association with trends in male-female size dimorphism, sexual pattern and sperm competition. The short-term, localized, nature of spawning aggregations renders species with this reproductive mode particularly vulnerable to fishing pressure at spawning sites. Aggregating species, therefore, may require special management consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023817
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of [5 + 6]-, [6 + 6]-, and [6 + 7]-Bicyclic Guanidines from C,C'-Bis(iminophosphoranes) (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1641-1652 
    Details
    ISSN: 0009-2940
    Keywords: Bis(iminophosphoranes) ; Guanidines, bicyclic ; Aza Wittig reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A one-pot synthesis of [5 + 6]-, [6 + 6]-, and [6 + 7]-rigid bicyclic guanidines (6, 8, 19, 21, 23) based on a bis(iminophosphorane)-mediated annulation strategy is reported. The crystal and molecular structure of the parent [5 + 6]-bicyclic guanidine 8 has been established by X-ray diffraction. The crystallographically independent molecule forms dimers through a centre of symmetry by N-H-N hydrogen bonds. The molecule, and therefore the dimer, is statistically disordered in a 65/35 ratio. A statistical study of N-H-N hydrogen bonds of this kind of dimers has been carried out by using the Cambridge Structural Database.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270916
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  • 4
    Electronic Resource
    Electronic Resource
    Broadband dielectric spectroscopy on an oxovanadium metallomesogen compoundThis work was supported by the CICYT (Spain, project MAT-91-0962-C02-02) and the EC Human Capital and Mobility Programme (ERB4050 PL922749). (1994)
    Weinheim : Wiley-Blackwell
    Advanced Materials 6 (1994), S. 941-944 
    Details
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19940061208
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  • 5
    Electronic Resource
    Electronic Resource
    Behaviour of a silica filler surface-modified with boron-amine groups (1994)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 217 (1994), S. 107-117 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Verhalten von mit primären Boramingruppen modifizierten Silikat-Füllstoffen wurde unter verschiedenen Reaktionsbedingungen untersucht. Der Füllstoff mit den besten Verstärkungseigenschaften wurde eingesetzt, um zwei unterschiedliche Vulkanisationssysteme zu vergleichen: ein wirksames Vulkanisationsverfahren (EV), das nach ISO als Methode zur Untersuchung des Verstärkungsverhaltens neuer Silikate empfohlen wird, sowie ein konventionelles Verfahren. Die besten Ergebnisse werden mit Silikat erhalten, welches 3 h bei 500°C behandelt wurde; unter diesen Bedingungen werden die meisten der primären Boramingruppen fixiert. Die Eigenschaften des nach dem EV-Verfahren modifizierten Silikats ähneln denen von mit Silan modifizierten Silikaten und sind in einigen Fallen besser als jene, welche nach dem konventionellen Verfahren erhalten werden. In allen Fallen wird die verstarkende Wirkung von gefällten Silikat-Füllstoffen durch die Boraminbehandlung verbessert.
    Notes: The behaviour of silica fillers modified with primary boron-amine groups has been studied under different reaction conditions. The filler with the best reinforcing properties was used to compare two different vulcanization systems: an efficient vulcanization system, EV, which is the recommended ISO Standards method to study the reinforcing behaviour of new silicas, and a conventional vulcanization system.The results indicate that the best properties are obtained with silica treated for 3 h at 500°C, reaction conditions which fix most of the primary boron-amine groups. Using the EV system, the properties of this modified silica are similar to those of silane-modified silica, and in some cases better than those obtained with a conventional vulcanization system. In all cases, the boron-amination treatment significantly improves the behaviour of precipitated silica as a reinforcing filler.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1994.052170111
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  • 6
    Electronic Resource
    Electronic Resource
    Targeting of aequorin for calcium monitoring in intracellular compartments (1994)
    New York : Wiley-Blackwell
    Journal of Bioluminescence and Chemiluminescence 9 (1994), S. 177-184 
    Details
    ISSN: 0884-3996
    Keywords: Photoproteins ; calcium ; organelles ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We have recently developed a new method for monitoring Ca2+ concentrations in defined cell compartments. The cDNA encoding the Ca2+-sensitive photoprotein aequorin has been modified in order to include specific targeting sequences and expressed in eukaryotic cells; the recombinant protein, specifically located inside the cells, has allowed the direct study of mitochondrial and nuclear Ca2+ concentrations in living cells. The principles, and the application, of this new methodology are discussed in this article.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bio.1170090312
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  • 7
    Electronic Resource
    Electronic Resource
    A novel preparation route of aromatic poly(amido-imide)s (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 15 (1994), S. 95-98 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1994.030150201
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  • 8
    Electronic Resource
    Electronic Resource
    Analysis of a bioactive synthetic analogue of tuftsin by tandem mass spectrometry: Anomalous fast atom bombardment activated processes (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 262-266 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fast atom bombardment (FAB) tandem mass spectrometry has been used to analyse the biologically potent, partially modified retro-inverso (PMRI) synthetic isomer of tuftsin: this compound represents the active peptide of the fraction of γ-globulin (leukokinin) which binds specifically to blood neutrophilic leukocytes and monocytes. Protonated molecules and fragment ions were collisionally dissociated at low energies in a triple-quadrupole mass spectrometer to yield a complete picture of the reactions that occur in the condensed and in the gas phase. The study shows that, when retro-inversion is within the N-terminal amino acid, charge localization at the basic sites (possibly at the N-terminus) induces a marked decomposition of the molecule, the loss of ammonia being the most favourable fragmentation process. Also, artifacts are formed in the liquid phase via bimolecular reactions promoted by the high-energy beam. The findings indicate that despite the fact that PMRI isomers of this type are stable against exo-peptidases and also stable under acidic conditions, they appear to be labile under conditions where the energy deposition, due to FAB is necessarily high.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200230504
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis, characterization, and degradation of block polyesteramides containing poly(L-lactide) segments (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 1813-1820 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Random multiblock polyesteramides (PEAs) having polyester (PE) content of 20-50 wt % have been prepared by low-temperature polycondensation using sebacoyl chloride, 1,6-diaminohexane, and telechelic oligomers of L-lactide with Mn = 600-1500. The PEAs were characterized by IR and 1H-NMR spectroscopy, wide-angle X-ray diffraction, and thermal analysis. Only the polyamide segments are able to crystallize, and the crystallinity depends on the composition and architecture of the PEAs. From viscosity and IR measurements it was established that the chain degradation of PEA powders or films suspended in buffer solutions occurs by hydrolysis of the ester linkages. The degradation rate is influenced by pH, PE content, and, to a lesser extent, by crystallinity. © 1992 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070461013
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  • 10
    Electronic Resource
    Electronic Resource
    Mass spectrometric study of simple olefinic flames: Comparison with laser diagnostics of C2H4/O2/Ar flames at 20 torr (1992)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 6 (1992), S. 278-283 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A new research apparatus for characterization of low-pressure premixed flames has been developed. This instrument incorporates several spectral techniques in one apparatus so that various diagnostic techniques can be quantitatively compared and the usable detection range expanded. Features include detection by mass analysis with a triple quadrupole mass spectrometer and by laser techniques such as laser-induced fluorescence. Temperature profiles of the flame both with and without the mass spectrometer probe were obtained by thermocople. Concentration profiles of the highly reactive flame species H·, O, and OH· were obtained and compared.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290060411
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