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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 1834-1842 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Charged dust particles electrostatically trapped in rf plasmas may exhibit kinetic energies greatly exceeding that of the surrounding gas. The high particle energies are a result of charged particle interactions with local potential fields perturbed by the presence of neighboring particles. Laser Doppler velocimetry is used to experimentally investigate the two-dimensional dynamics of monodisperse 10.2 μm polystyrene latex spherical particles trapped in an argon plasma. Spatially resolved particle velocities and local particle concentrations are reported for variations in rf power and pressure. The experimental results are compared with laser light scatter, often employed for studying particle dynamics. Various theories are reviewed in an attempt to interpret the experimental results. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 134-136 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using a high-resolution magneto-optical imaging technique, we study the flow of transport currents around cracks in monofilament (BiPb)2Sr2Ca2Cu2Ox composite conductors. Shunting through the Ag clad is directly observed. The current in the silver decays exponentially with distance from the crack as expected in a one dimensional distributed resistance model. At 77 K, the transfer length, λ, is approximately 0.56 mm, implying an interface resistivity of 7.5×10−8 Ω cm2. This transfer length is found to increase slightly with increasing temperature. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 102 (1980), S. 7715-7718 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 56 (1934), S. 153-154 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd.
    Alimentary pharmacology & therapeutics 11 (1997), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The effect of acute pentoxifylline treatment in an experimental model of colitis was assessed using the trinitrobenzene sulphonic acid (TNBS)-induced rat model of colitis.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:Animals were treated with intracolonic injection (250 μL) of TNBS (50 mg in 50% ethanol) to induce inflammation and ulcers. Animals received pentoxifilline (100 mg/kg intracolonically) or saline 24 and 48 h following TNBS treatment. Five days following TNBS treatment, colons were dissected and scored according to the morphology damage score. The colons were then rolled longitudinally, fixed in formalin and embedded in paraffin. The collagen content of colonic sections was determined by a Sirius red–Fast green technique.〈section xml:id="abs1-3"〉〈title type="main"〉Results:Animals treated with TNBS alone had significantly higher gross morphology damage scores compared to animals treated with saline. Pentoxifylline significantly reduced the gross morphology damage score in animals receiving TNBS. Colonic collagen levels were significantly elevated in TNBS-treated animals compared to animals receiving saline. Pentoxifylline treatment did not alter the collagen content of colons from TNBS-treated animals.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusion:TNBS treatment significantly elevates morphology damage score compared to controls. The results also suggest that colonic collagen was significantly elevated in animals treated with TNBS compared to controls. Pentoxifylline treatment was not sufficient to reduce the elevation in colonic collagen, although pentoxifylline treatment was sufficient to reduce the pathological changes due to TNBS, thus bringing the morphology damage score down to control levels.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 377 (1995), S. 687-688 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - Over the past several decades, the observed increase in mean temperatures over much of the world has been a result of a disproportionate increase in night-time temperatures1. Here we show that, in the United States and the former Soviet Union, the evaporation of water, as measured by ...
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1420-9071
    Keywords: HIV RNase H ; inhibitors ; novenamines ; micelles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Few inhibitors of the RNase H function associatesd with the HIV-1 reverse transcriptase have been discovered to date. We observed that three novenamines, U-34445, U-35122, and U-35401, are specific inhibitors of the HIV-1 RT RNase H function. All three compounds are strong amphiphiles and contain one ionizable group. Hence, a priori, in aqueous solutions the inhibitors might exist in at least four different physical states, namely protonated monomers, ionized monomers, protonated micelles and ionized micelles. The three inhibitors all yielded anomalous dose-response curves, indicating that the four molecular species have different inhibitory potentials. In order to identify the inhibitory species, the amphiphilic properties of these compounds were studied. It was established that in alkaline solutions, around pH 8, all compounds are ionized and form micelles at concentrations above their CMC. Both the protonated and the ionized forms of these molecules from stable insoluble monomolecular layers at the air/water interface. The anomalies of the dose-response curves can be resolved by taking into account the fact that, in solution, the relative proportion of these molecules in each physical state depends on the pH and on their analytical concentration. Thus interpreted the results indicate that RNase H is inhibited only by the ionized micellar form of these compounds and not by their monomeric form. Around their pKa (∼pH5) the three componds reproducibly form uniformly sized, self-emulsified colloidal particles that may be used as an efficient drug delivery system.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0428
    Keywords: Ciglitazone ; C57BL/6J-ob/ob mice ; C57BL/KsJ-db/db mice ; β-cell granulation ; electron microscopy ; rough endoplasmic reticulum ; Golgi apparatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pancreases of treated and control male C57BL/6J-ob/ob and C57BL/KsJ-db/db mice were evaluated by qualitative and morphometric microscopic techniques to determine the effects of chronic ciglitazone treatment on the morphology of β cells and surface area and number of pancreatic islets. The β cells of treated ob/ob and db/db mice displayed moderate to heavy granulation whereas most β cells of untreated obese and diabetic mice were extensively degranulated. Although moderate proliferation of the rough endoplasmic reticulum and Golgi apparatus was evident in some β cells of treated db/db mice, both groups of treated ob/ob and db/db mice displayed an improved pattern of insulin synthesis and storage. In contrast, the β cells of untreated ob/ob and db/db mice were in a severe state of stress which was indicated by extensive hypertrophy of the rough endoplasmic reticulum, Golgi apparatus and mitochondria. Some β cells of untreated db/ db mice also displayed lysosome aggregates indicative of early stages of necrosis. Morphometric analysis revealed that the surface area of islets of treated ob/ob mice was significantly smaller in comparison with that of untreated ob/ob mice. Since the surface area of islets of treated C57BL/6J-+/? mice (lean littermates of ob/ob mice) was less than that of treated ob/ob mice, the progression of islet hypertrophy in the obese mice was probably arrested or attenuated but not to the level of the treated +/? mice. The number of pancreatic islets was significantly greater in treated than in untreated db/ db mice. A majority of the islets of untreated db/db mice were atrophie and consisted of acinar and endocrine cells whereas most of the islets of treated db/db mice appeared to be intact and unremarkable. The results of this study suggest that ciglitazone is an effective hypoglycaemic agent which may directly or indirectly promote β-cell regranulation and an improved pattern of insulin synthesis and storage in ob/ob and db/db mice. However, in treated db/db mice, there still was some evidence of stress in the β cells. Overall, the prolonged treatment with ciglitazone also seemed to inhibit the hypertrophy of islets in ob/ob mice and protect the structural integrity and viability of islets in db/db mice.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 95 (1997), S. 757-763 
    ISSN: 1432-2242
    Keywords: Key words Alien gene transfer ; Intergeneric hybrids ; Molecular markers ; Thinopyrum ; Triticum turgidum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The objective of this study was to detect the presence of alien chromatin in intergeneric hybrids of durum wheat (Triticum turgidum, 2n=4x=28; AABB genomes) with the perennial grass Thinopyrum junceiforme (2n=4x=28; J1J1J2J2) using RAPD markers. The first step was to identify amplification of species-specific DNA markers in the parental grass species and durum wheat cultivars. Initially, the genomic DNA of five grass species (Thinopyrum junceiforme, Th. bessarabicum, Lophopyrum elongatum, Leymus karataviensis and Elytrigia pycnantha) and selected durum cultivars (‘Langdon’, ‘Durox’, ‘Lloyd’, ‘Monroe’, and ‘Medora’) was screened with 40 oligonucleotide primers (nano-mers). Three oligonucleotides that amplified DNA fragments specific to a grass species or to a durum cultivar were identified. Primer PR21 amplified DNA fragments specific to each of the five durum cultivars, and primers PR22 and PR23 amplified fragments specific to each of the grass species. Intergeneric hybrids between the durum cultivars ‘Langdon’, ‘Lloyd’ and ‘Durox’ and Th. junceiforme, and their backcross (BC) progeny were screened with all 40 primers. Six primers amplified parent-specific DNA fragments in the F1 hybrids and their BC1 progeny. Three primers, PR22, PR23 and PR41, that amplified Th. junceiforme DNA fragments in both F1 and BC1 were further analyzed. The presence of an amplified 1.7-kb Th. junceiforme DNA fragment in the F1 hybrids and BC1 progeny was confirmed using Southern analysis by hybridization with both Th. junceiforme genomic DNA and Th. junceiforme DNA amplified with primer PR41. With the exception of line BC1F2 no. 5, five selfed progeny of BC1 and a BC2 of line 3 (BC1F2 no. 3בLloyd’) from a cross of ‘Lloyd’×Th. junceiforme showed the presence of the 1.7-kb DNA fragment. All selfed BC1 and BC2 lines retained the 600-bp fragment that was confirmed after hybridization with Th. junceiforme DNA amplified with primer PR22. Other experiments using RFLP markers also showed the presence of up to seven Th. junceiforme DNA fragments in the F1 hybrids and their BC progeny after hybridization with Th. junceiforme DNA amplified with primer PR41. These studies show the usefulness of molecular markers in detecting alien chromatin/DNA fragments in intergeneric hybrids with durum wheat.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 260 (1998), S. 372-380 
    ISSN: 1617-4623
    Keywords: Key words Maize ; Flavonoids ; Myb ; Tandem repeats ; Tissue-specific silencing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The maize P gene encodes a Myb-homologous transcriptional regulator of flavonoid pigmentation in floral organs, and different P gene alleles condition precise tissue- and organ-specific pigmentation patterns. To determine the molecular basis for allele-specific expression patterns, we have isolated and compared two natural alleles of the P gene which differ in expression, structure and copy number. The P-rr allele is associated with pigmentation of most floral tissues and contains a single copy of the P gene. In contrast, the P-wr allele restricts pigmentation to a subset of floral tissues, and is composed of six gene copies arranged in a tandem head-to-tail array. Each of the six repeats contains a single P gene, including regulatory and coding sequences. Despite the six-fold tandem repetition of P-wr gene copies, P-wr mRNA levels in kernel pericarp are much reduced compared to mRNA levels from the single-copy P-rr gene. Moreover, the P-wr multicopy complex is hypermethylated relative to P-rr. Thus, maize P gene alleles may represent a natural system for studying the effects of methylation and gene copy number on tissue-specific gene expression. We discuss the possibility that somatic pairing of repeated gene copies may be involved in regulating gene expression.
    Type of Medium: Electronic Resource
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