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  • American Institute of Physics (AIP)  (441)
  • Blackwell Publishing Ltd  (437)
  • Wiley-Blackwell  (358)
  • Blackwell Science Pty  (34)
  • Macmillian Magazines Ltd.  (21)
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  • 1
    ISSN: 1434-1948
    Keywords: Palladium ; Dithiadiazole ; Radicals ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new 1,2,3,5-dithiadiazoles, [4-(4′-C5H4N)CN2S2] (L1) and [4-(3′-C5H4N)CN2S2] (L2), with different pyridyl groups at the 4-position were prepared. As Lewis bases, the dithiadiazoles reacted with Lewis acids via their pyridyl groups to form acid-base adducts with retention of the five-membered dithiadiazole ring. Ligands L1 and L2 reacted with excess triethylborane to give L1BEt3 and L2BEt3 (1a and 1b) and with Mn(CO)5Br to give the fac-Mn(CO)3Br(L1)2 (2a) and fac-Mn(CO)3Br(L2)2 (2b) complexes. When reacted with Pd0 complexes, namely, Pd(PPh3)4 and a mixture of [Pd2(dba)3] and dppf, the dithiadiazoles underwent ring-opening reaction by reductive cleavage of the S-S bond of the dithiadiazole ring. The resulting formation of Pd-S bonds gave the corresponding trinuclear complexes [Pd3{μ-SNC(4′-C5H4N)NS-S,S′}2(PPh3)4] (3a), [Pd3{μ-SNC(3′-C5H4N)NS-S,S′}2(PPh3)4] (3b), and [Pd3{μ-SNC(4′-C5H4N)NS-S,S′}2(dppf)2] (4) [dba = dibenzylideneacetone, dppf = 1,1′-bis(diphenylphosphanyl)ferrocene]. Complexes 3a and 3b reacted with excess triethylborane to give the corresponding acid-base adducts [Pd3{μ-SNC(4′-C5H4NBEt3)NS-S,S′}2(PPh3)4] (5a) and [Pd3{μ-SNC(3′-C5H4NBEt3)NS-S,S′}2(PPh3)4] (5b.) Complex 3a reacted with Mn(CO)5Br to give {[Pd3{μ-SNC(4′-C5H4N)NS-S,S′}2(PPh3)4][MnBr(CO)3]}n (6). The structures of 3a, 5a, and 5b were established by X-ray crystallography.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Li L, Xu JN, Wong YH, Wong JTY, Pang SF, Shiu SYW. Molecular and cellular analyses of melatonin receptor-mediated cAMP signaling in rat corpus epididymis. J. Pineal Res. 1998; 25:219–228. © Munksgaard, Copenhagen〈section xml:id="abs1-1"〉〈title type="main"〉AbstractBy using 2-[125I]iodomelatonin receptor binding studies, we have previously demonstrated high affinity melatonin receptors, the binding activities of which are regulated by testosterone, in the corpus epididymis of rats. In this report, some of the basic molecular and cellular characteristics of these high affinity melatonin receptors in rat corpus epididymis were analyzed. MEL1A and MEL1B receptor mRNAs were expressed by rat corpus epididymal epithelial cells as revealed by in situ hybridization. Functionally, these high affinity melatonin receptors are negatively coupled to adenylyl cyclase via pertussis toxin (PTX) sensitive Gi protein and the inhibitory effects of melatonin on forskolin-stimulated cAMP accumulation were enhanced by 5α-dihydrotestosterone (5α-DHT). Interestingly, opposing interactions between melatonin and (β-adrenergic receptor signaling in rat epididymal epithelial cells were observed with melatonin inhibiting norepinephrine- and isoproterenol-stimulated cAMP accumulation. In conclusion, our data support a modulatory action of melatonin, mediated via pertussis toxin-sensitive Gicoupled MEL1A and MEL1B receptors, in androgenic and adrenergic regulation of rat corpus epididymal epithelial cell functions.
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  • 3
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: © 1999 American Institute of Physics.
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3663-3665 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Time-resolved reflectance difference spectroscopy (TRDS) has been applied to study the dynamics and relaxation processes of the 2.7 eV ZnSe/GaAs interface state associated with Zn–As bonds. The instantaneous screening due to the photoexcited carriers and ∼18 ps recovery time of the 2.7 eV interface state is observed in the TRDS spectra. The rapid cooling of the hot carrier in the spectral region above the ZnSe band edge is also observed. © 1999 American Institute of Physics.
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 1915-1917 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: ZnS1−xTex (0≤x≤1) single-crystal alloy films were grown on GaAs and Si substrates by molecular beam epitaxy. Strong photoluminescence in the yellow to blue light region, with room-temperature external quantum efficiencies of 2%–4% at an unoptimized excitation wavelength of 365 nm, was observed. The enhancement of luminescence was attributed to the presence of Te isoelectronic hole traps in the films. Strong bowing of the band-gap energy as a function of composition x was also observed, with the minimum near x=0.7. The line width as well as the Stokes shift of the luminescence peak from the band edge were found to increase as Te composition decreases. © 1995 American Institute of Physics.
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  • 6
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
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  • 7
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Melatonin has been shown to regulate gene transcription through RZR/ROR nuclear receptors in mammalian cells. Thiazolidine dione CGP 52608 is a selective agonist of RZR/ROR receptors with little or no affinity for the cell surface G protein-coupled melatonin receptors. In this study, we addressed whether nuclear signaling may be involved in indoleamine-induced encystment of the unicellular dinoflagellates by examining their responses to CGP 52608. Three species of dinoflagellates (Alexandrium catenella, Amphidinium carterae, and Crypthecodinium cohnii) encysted in the presence of CGP 52608 and the responses were reversible and dose-dependent. Since a previous study has implicated the involvement of G proteins in mediating indoleamine-induced encystment of dinoflagellates, we explored the possibility of cross-talks between G protein-dependent and nuclear signaling pathways. The responses of A. catenella to either mastoparan (a direct activator of mammalian G proteins) or indoleamines were assessed in the presence or absence of CGP 52608. Interestingly, CGP 52608 synergized with either indoleamines or mastoparan to produce a more rapid encystment response. These findings suggest that nuclear signaling may be involved in the indoleamine-induced encystment of dinoflagellates.
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  • 8
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Exogenous indoleamines such as melatonin and 5-methoxytryptamine have been shown to induce cyst formation (encystment) in many species of dinoflagellate. Induction of inositol phosphates formation by indoleamine has previously been demonstrated in Crypthecodiniurn cohnii. In addition, depletion of extracellular Ca2+ blocks the indoleamine-induced encystment. In the present study, 12 indoleamines (including melatonin and related compounds) were examined for their abilities to induce Ca2+ influx, inositol phosphates formation, and encystment in C. cohnii. The results showed that melatonin, 5-methoxytryptamine, and the peptide toxin mastoparan stimulated 45Ca2+ influxes in dose- and time-dependent manners. The EC50 values of 5-methoxytrypramine and mastoparan to stimulate 45Ca2+ uptake were 2 mM and 35 μM, respectively. The 5-methoxytryptamine- and mastoparan-induced 45Ca2+ influx were partially attenuated by the calcium channel blockers, verapamil and ruthenium red. A series of indoleamines were examined for their structure-activity relationship on the induction of encystment and formation of inositol phosphates. Melatonin-induced inositol phosphates formation was completely blocked by U73122, indicating the possible involvement of phospholipase C. Taken together, we conclude that indoleamines may induce encystment of the dinoflagellate C. cohnii via parallel activation of phospholipase C and Ca2+ influx signaling pathways. However, activation of phospholipase C and Ca2+ influx are not always necessary or sufficient for inducing encystment. Also, these data provided the first direct evidence of a Ca2+ influx regulating mechanism in dinoflagellate C. cohnii.
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  • 9
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: As part of the ongoing sequencing of the complete Salmonella typhimurium LT2 genome, a partly ordered set of 416 lambda clones has been developed, representing over 90% of the genome. The average insert size is 17 kb. Sequences were obtained from both ends of each clone in this set. A total of over 600 kb of sequence has been deposited in the genome survey sequence section of GenBank. This resource of clones is available from the Salmonella Genome Stock Center. A preliminary comparison with the Escherichia coli K12 genome indicates that there are likely to be many hundred insertion deletion events, encompassing more than one gene, that distinguish these genomes. Fully 30% of the S. typhimurium sequences have no close homologs in the GenBank database.
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cutaneous pathology 21 (1994), S. 0 
    ISSN: 1600-0560
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We report an unusual case of vulvar acantholytic dermatosis with features of pemphigus vegetans in a 22-year-old Indian girl who presented with a “warty” lesion in her left labium majus. Following excision of this lesion, she presented with 2 localized recurrent lesions on the left and right labia majora about 21/2 years later which were also excised. All 3 biopsies showed histological features typical of pemphigus which included extensive suprabasal acautholysis with bullae formation, prominent villus-like processes at the base of the bullae, focal hyperkeratosis and papillomatosis, and the occasional mixed neutrophil and eosinophilic intraepidermal abscess. IgG and C3 immunofluorescence was positive in the intercellular spaces of the epidermis. These lesions, which probably represent a form of pemphigus vegetans, have not been previously reported as a cause of localized vulvar acantholytic dermatosis.
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