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  • 1
    Electronic Resource
    Electronic Resource
    Site, histological type, and thickness of primary cutaneous malignant melanoma in western Netherlands since 1980 (1997)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 136 (1997), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: An increasing incidence of cutaneous malignant melanoma had been observed in the Netherlands.Therefore, between 1989 and 1992 a preventive skin cancer campaign was organized in part of western Netherlands. The effect of this screening campaign has yet to be evaluated by investigating the distribution of all in situ and invasive primary cutaneous melanoma according to anatomical subsite, tumour thickness, and histological type in a population-based study during 1980–92. A total number of 2236 (1361 female; 875 male) invasive and 580 (395 female; 185 male) in situ melanomas were diagnosed. The median age of patients with thin lesions was 46 years, intermediate lesions 54 years, and thick lesions 65 years, which may be indicative of slow tumour progression. The median thickness of the invasive lesions was 0·9 mm for women and 1·1 mm for men and the invasive to in situ ratio was 3·4 for female and 4·7 for male subjects, suggesting a reasonable awareness of melanoma in this population. The relative tumour density (RTD) was remarkably high for melanomas in the head/neck area for both sexes and invasive melanoma on the male trunk and the lower legs of females. The low RTD of invasive melanomas on the lower limbs of men and the high density in the head/neck area for both sexes are remarkable and support the aetiological role of ultraviolet exposure. It is concluded that our findings are in many ways similar to those of other descriptive studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.1997.d01-1236.x
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental demonstration of a binary wire for quantum-dot cellular automata (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 2875-2877 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental studies are presented of a binary wire based on the quantum-dot cellular automata computational paradigm. The binary wire consists of capacitively coupled double-dot cells charged with single electrons. The polarization switch caused by an applied input signal in one cell leads to the change in polarization of the adjacent cell and so on down the line, as in falling dominos. Wire polarization was measured using single islands as electrometers. Experimental results are in very good agreement with the theory and confirm there are no metastable states in the wire. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124043
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  • 3
    Electronic Resource
    Electronic Resource
    Monthly variation in sperm motility in common carp assessed using computer-assisted sperm analysis (CASA) (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 48 (1996), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Sperm motility variables from the milt of the common carp Cyprinus carpio were assessed using a computer-assisted sperm analysis (CASA) system across several months (March-August 1992) known to encompass the natural spawning period. Two-year-old pond-raised males obtained each month were primed with an exogeneous hormone injection of carp pituitary extract and stripped of milt 18–24h later. The milt was diluted, activated and videotaped using a high-speed (200 Hz) videocamera and recorder. Videotaped samples were subsequently analysed using the CellTrak/S CASA system (Motion Analysis Corp.) for percent motility, curvilinear and straight-line velocity. In addition to assessing changes in motility parameters across several months, a comparison was made between two predilution/ activation media combinations (homologous seminal plasma/NaCl+HEPES v. 2-h incubation in 200 mM KCl+Tris/Tris). The percentage of motile cells assessed immediately after activation was significantly greater in the summer months (May, June, July) when compared to a spring sampling point (March); when assessed 1 min after activation, cells prediluted in seminal plasma maintained a higher percentage of motility than those prediluted in KC1. Curvilinear and straight-line velocities exhibited a slight seasonal trend; variations in response to the predilution treatments were observed with these measurements. Sperm count gradually increased through April and May (9–63 × 109 to 2–38 × lO10ml– 1 milt), declined in June and July (to 1–83 × lO10ml– 1 milt), and was followed by a steep increase in August (2–74 × 1010 ml– 1 milt). Mean seminal plasma osmolality remained relatively constant (250–265 mOsmol kg – 1) throughout the sampling period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1996.tb01815.x
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  • 4
    Electronic Resource
    Electronic Resource
    Computer-assisted motion analysis of sperm from the common carp (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 47 (1995), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Computer-assisted semen analysis (CASA) technology was applied to the measurement of sperm motility parameters in the common carp Cyprinus carpio. Activated sperm were videotaped at 200 frames s−1 and analysed with the CellTrak/S CASA research system. The percentage of motile cells and both sperm head curvilinear velocity and straight-line velocity were measured following exposure of carp sperm to three predilution conditions and activation in media of differing ionic strengths and osmotic pressures. The highest percentage of motile sperm was obtained following predilution of sperm in seminal plasma and activation in Na-HEPES buffer pH 8.0. This level of motility was equalled after predilution in 200 mm KCl for 2 h. Straight-line velocities and curvilinear velocities of 130 μm s−1 and 210 μm s−1, respectively, were observed. Duration of motility was higher under seminal plasma predilution conditions (over 50% motile sperm at 55 s post-activation). The application provides a sound basis for the assessment of Sperm Characteristics in fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1995.tb06023.x
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  • 5
    Electronic Resource
    Electronic Resource
    Reproductive physiology of yellow perch (Perca flavescens): environmental and endocrinological cues (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of applied ichthyology 12 (1996), S. 0 
    Details
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An understanding of the mechanisms involved in the regulation of reproductive processes in yellow perch is fundamental for intensive culture of this commercially important, freshwater, perciform fish. This paper describes the annual reproductive cycle of female and male perch. It presents the current state of knowledge on the regulation of ovarian steroidogenesis, final maturation of oocytes and ovulation in this species. Moreover, data concerning biochemistry of spermatozoa and seminal plasma as well as testicular steroidogenesis are summarized. In addition to endocrinological factors, the involvement of environmental (photoperiod and temperature) cues in the regulation of yellow perch reproduction is reviewed. Finally, practical aspects of controlling perch reproduction are outlined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0426.1996.tb00079.x
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  • 6
    Electronic Resource
    Electronic Resource
    Highly saturated packings and reduced coverings (1998)
    Springer
    Monatshefte für Mathematik 125 (1998), S. 127-145 
    Details
    ISSN: 1436-5081
    Keywords: 52C17 ; packing ; covering ; saturated ; reduced ; convex ; body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We introduce and study certain notions which might serve as substitutes for maximum density packings and minimum density coverings. A body is a compact connected set which is the closure of its interior. A packingP with congruent replicas of a bodyK isn-saturated if non−1 members of it can be replaced withn replicas ofK, and it is completely saturated if it isn-saturated for eachn≥1. Similarly, a coveringC with congruent replicas of a bodyK isn-reduced if non members of it can be replaced byn−1 replicas ofK without uncovering a portion of the space, and its is completely reduced if it isn-reduced for eachn≥1. We prove that every bodyK ind-dimensional Euclidean or hyperbolic space admits both ann-saturated packing and ann-reduced covering with replicas ofK. Under some assumptions onK⊂E d (somewhat weaker than convexity), we prove the existence of completely saturated packings and completely reduced coverings, but in general, the problem of existence of completely saturated packings, and completely reduced coverings remains unsolved. Also, we investigate some problems related to the the densities ofn-saturated packings andn-reduced coverings. Among other things, we prove that there exists an upper bound for the density of ad+2-reduced covering ofE d with congruent balls, and we produce some density bounds for then-saturated packings andn-reduced coverings of the plane with congruent circles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01332823
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  • 7
    Electronic Resource
    Electronic Resource
    Isomerization of substituted tricyclic 4,5-dihydropyrazoles (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 971-977 
    Details
    ISSN: 1434-4475
    Keywords: Isomerization ; N-Substituted 2H-benz[g]indazoles ; 1H and13C NMR spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Isomerisierung einiger tricyclischer 2-Pyrazoline mit N-Carbamoyl-, N-Thiocarbamoyl-und N-Phenyl-substituenten unter saurer und basischer Katalyse wurde untersucht. Ausgehend von dencis odertrans 3-H,3a-H-Diastereomeren wurdencis- undtrans Gleichgewichtsgemische gewonnen, die getrennt und durch1H- und13C-NMR-Spektroskopie untersucht wurden. Ein Mechanismus für die Isomerisierung von Pyrazolinen wird vorgeschlagen, der durch den Deuteriumaustausch in Position 3a-C unterstützt wird.
    Notes: Summary The acid and base catalyzed isomerization of some tricyclic 2-pyrazolines with N-Carbamoyl-,N-thiocarbamoyl-and N-phenyl substituents was investigated. Starting fromcis ortrans 3-H, 3a-H diastereomers, equilibrium mixtures ofcis andtrans diastereomers were prepared which were separated and subsequently studied by1H NMR and13C NMR spectroscopy. A mechanism for the isomerization of the pyrazolines is suggested, supported by a deuterium exchange at C-3a.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807038
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  • 8
    Electronic Resource
    Electronic Resource
    Conformational analysis of 2,3-dihydro-2,2-dimethyl-1,4-benzoxazepines and their 1,5-isomers (1997)
    Springer
    Monatshefte für Chemie 128 (1997), S. 625-632 
    Details
    ISSN: 1434-4475
    Keywords: Ring inversion ; Stereochemistry ; Dihydro-1,4-benzoxazepines ; Dihydro-1,5-benzoxaepines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Konformation von 2,3-Dihydro-2,2-dimethyl-1,4-benzoxazepinen (1,3,5 und7) und ihren 1,5-Isomeren (2,4 und6) wurde mittels temperaturabhängiger NMR-Spektroskopie untersucht. Der Einfluß von Substituenten auf die Ringinversion wird diskutiert. Die erhaltenen Resultate werden durch AMl-Rechnungen bestätigit.
    Notes: Summary Conformational analysis of 2,3-dihydro-2,2-dimethyl-1,4-benzoxazepines (1,3,5, and7) and their 1,5-isomers (2,4, and6) was performed by temperature dependent NMR measurements. The effect of substituents on the ring inversion was studied. The results obtained were corroborated by AMl calculations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807593
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and spectroscopic investigation of some dimeric coumarin and furanocoumarin models (1997)
    Springer
    Monatshefte für Chemie 128 (1997), S. 701-712 
    Details
    ISSN: 1434-4475
    Keywords: bis-Coumarins ; bis-Furanocoumarins ; Chirality ; Aldehyde hydrates ; 1H NMR ; 13C NMR ; Mass spectrometry ; Fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Synthese einiger dimerer Cumarin- und Furanocumarin-Modellverbindungen und ihre Strukturaufklärung mit1H- und13C-NMR- sowie Massenspektrometrie werden beschrieben. In Gegenwart von Feuchtigkeit werden einige der Aldehyde von ihren Hydraten begleitet. Verdoppelungen der Methoxy-1H-Signale von8 in Anwesenheit eines chiralen Lanthanoid-Verschiebungsreagenzes beweisen, daß8 ein Dimer ist. In den Massenspektren finden sich Hinweise für heterolytische Spaltungen der O-C-Bindungen. Solche Fragmentierungen sind bei aromatischen Ethern ungewöhnlich.
    Notes: Summary The synthesis of some dimeric coumarin and furanocoumarin models and their structure elucidation by1H NMR,13C NMR, and mass spectroscopy is presented. In the presence of moisture some aldehydes are accompanied by their hydrates. Methoxy signal doubling in the presence of a chiral lanthanide shift reagent proves the dimeric nature of compound8. In the mass spectra, heterolytic cleavage of the O-C linkage was noticed which is a rare fragmentation in the case of aromatic ethers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807602
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  • 10
    Electronic Resource
    Electronic Resource
    Stereoselective epoxidation of 2-arylidene-1-indanones and 2-arylidene-1-benzosuberones (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 683-690 
    Details
    ISSN: 1434-4475
    Keywords: 2-Arylidene-1-indanones ; 2-Arylidene-1-benzosuberones ; Dimethyldioxirane ; Stereoselective epoxidations ; Epoxides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Oxidation der (E)- und (Z)-Isomeren von 2-Aryliden-1-indanonen (1) und 2-Aryliden-1-benzosuberonen (4) mit alkalischem Wasserstoffperoxyd (Methodei) liefert aus beiden Isomeren die Spiroepoxidetrans-2a–g undtrans-5a–g als einzige Produkte. Epoxidierung der (E)-Isomeren1a–g und4a–g mit Dimethyldioxiran (Methodeii) ergab die entsprechendentrans-Spiroepoxide in sehr guten Ausbeuten, während die (Z)-Isomeren1a,c,e und4a,c,e diecis-Spiroepoxide in nur mäßiger Ausbeute liefern. Oxidation von (Z)-1c und (Z)-4c,e mit Dimethyldioxiran (Methodeii) ergab die Dione3c und6c,e sowie einige Nebenprodukte. Wurden (Z)-1a,c,e und (Z)-4a,c,e einer Epoxidation mitm-Chlorperbenzoesäure (Methodeiii) unterworfen, entstanden 6:1-Gemische der Spiroepoxidecis-2a,c,e undtrans-2a,c,e odercis-5a,c,e undtrans-5a,c,e.
    Notes: Summary Oxidation of the (E) and (Z) isomers of 2-arylidene-1-indanones (1) and 2-arylidene-1-benzosuberones (4) by alkaline hydrogen peroxide (methodi) afforded the spiroepoxidestrans-2a–g andtrans-5a–g from both isomers as sole products in high yields. On the other hand, dimethyldioxirane epoxidation(methodii) of the (E) isomers1a–g and4a–g gave the correspondingtrans spiroepoxides in good yields, whereas the (Z) isomers1a,c,e and4a,c,e led to thecis spiroepoxides in moderate yields. Dimethyldioxirane oxidation (methodii) of (Z)-1c and (Z)-4c,e gave diones3c and6c,e as by-products as well. Epoxidation of (Z)-1a,c,e and (Z)-4a,c,e bym-chloroperoxybenzoic acid (methodiii) resulted inca. 6:1 mixtures ofcis-2a,c,e andtrans-2a,c,e orcis-5a,c,e andtrans-5a,c,e spiroepoxides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00817259
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