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  • 1
    Electronic Resource
    Electronic Resource
    Site transfer of Si in GaAs after heavy ion MeV implantation and annealing (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 2692-2699 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical and optical properties of n-type and p-type epitaxial GaAs layers have been studied after MeV implantation of heavy (Xe and Er) ions. All implanted layers were highly resistive immediately after implantation. Annealing to only moderate temperature (725 °C) recovered the as-grown electrical properties of beryllium-doped p-type layers. However, after annealing silicon-doped n-type layers, we observe a dramatic change from the as-grown carrier profiles. After anneal, the silicon-doped, n-type layers became conductive but the carrier profiles were markedly different from the as-grown material. A significant thickness of the implanted portion of the epitaxial layers shows distinct p-type conductivity after annealing. We have correlated this p-type activity with a transfer of silicon from the gallium sublattice (SiGa) to the arsenic sublattice (SiAs). The site transfer is viewed to result from the altered thermodynamics governing site occupancy during annealing of Si in GaAs under the unique damage conditions produced by heavy ion MeV implantation. Additionally, the observed thermal stability of the site transfer process above 875 °C may have implications for implantation isolation techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351518
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  • 2
    Electronic Resource
    Electronic Resource
    Ion implantation into (x11)A-oriented InP and GaAs (x≤4) (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 7774-7778 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Si, Ge, and Be implantations were performed into (x11)A-oriented semi-insulating InP and GaAs substrates for x≤4. For comparison some of the implantations were also performed into (110)- and (100)-oriented substrates. For 200 keV/5×1013 cm−2 Si and 200 keV/3×1013 cm−2 Ge implants after 850 °C/7 s annealing, the InP is always n type with similar sheet resistance independent of the substrate orientation. No in-diffusion of Si or Ge was observed after annealing for any substrate orientation. Similar behavior was observed for Si implants in GaAs and for Si/B co-implants in both InP and GaAs. Photoluminescence measurements were performed on the Si- and Si/B-implanted InP and GaAs. For 30 keV/1.5×1014 cm−2 Be implants in both InP and GaAs, the in-diffusion of Be in (311)A-oriented substrates is less compared to the (100) material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356612
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  • 3
    Electronic Resource
    Electronic Resource
    Evidence of donor–acceptor pair recombination from a new emission band in semiconducting diamond (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 2136-2138 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Steady state and time resolved photoluminescence studies of type IIb boron-doped synthetic diamond reveal a new broad red emission band that exhibits many of the features of classic donor–acceptor pair recombination. This recombination is thought to be between an as-yet unidentified neutral donor, possibly nitrogen related, approximately 3.6 eV below the conduction band edge and neutral boron acceptors at 0.37 eV above the valence band edge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.111710
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  • 4
    Electronic Resource
    Electronic Resource
    Photoluminescence and magnetic resonance studies of Er3+ in MeV ion-implanted GaAs (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 502-504 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of post-implantation annealing have been studied in MeV Er-implanted GaAs by monitoring the Er3+ electron paramagnetic resonance (EPR) signal as well as the Er3+ and near-band-edge photoluminescence (PL) spectra as a function of the anneal temperature. Er3+ PL is observed from several distinct Er sites in the annealed material. In addition, the observed dependences upon anneal temperature suggest that the Er3+ PL is emitted from centers that are not in the Er3+ state at equilibrium. Absolute EPR measurements of the Er3+ concentration indicate that only a small fraction (〈0.1%) of the Er in the sample is Er3+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104621
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  • 5
    Electronic Resource
    Electronic Resource
    Short report: cefprozil for the eradication of Helicobacter pylori infection (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 6 (1992), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Helicobacter pylori infection has proven to be extraordinarily difficult to eradicate. Antimicrobial monotherapies have been particularly disappointing, with most eradication rates in the range of 0 to 15%. We evaluated cefprozil (250 mg q.d.s. for 14 days) in 12 H. pylori-infected subjects. The 13C-urea breath test was used to evaluate effectiveness of therapy. Eradication was defined as a negative urea breath test 4 to 6 weeks after the end of treatment. Suppression of H. pylori was demonstrated in 4 of 12 (33%) by a negative urea breath test two days after start of treatment. H. pylori infection was not eradicated in any subject (0%). Adverse events were intermittent and mild. Cefprozil does not appear to offer promise as monotherapy for the eradication of H. pylori.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2036.1992.tb00564.x
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  • 6
    Electronic Resource
    Electronic Resource
    Short report: a non-metronidazole triple therapy for eradication of Helicobacter pylori infection–tetracycline, amoxicillin, bismuth (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 7 (1993), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Triple therapies using bismuth, metronidazole and tetracycline or amoxicillin were the first truly successful anti-H. pylori therapies. Metronidazole resistance has become an increasing problem that has severely limited the usefulness of the original triple therapy. Resistance to tetracycline or amoxicillin has not been reported and both are effective against H. pylori. We therefore tested a new triple therapy consisting of 500 mg tetracycline, 500 mg amoxicillin, and 2 tablets of bismuth subsalicylate each administered four times daily (with meals and at bedtime) for 14 days during treatment with ranitidine 300 mg daily. H. pylori eradication was defined as no evidence of H. pylori one or more months after stopping therapy. H. pylori status was evaluated by a combination of urea breath test and histology. Sixteen patients with H. pylori infection and active peptic ulcers were enrolled. The new triple therapy was successful in only 7 individuals (43%). Metronidazole appears to be critical for the effectiveness of the original triple therapy. An alternative to metronidazole will be required for a new successful triple therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2036.1993.tb00076.x
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  • 7
    Electronic Resource
    Electronic Resource
    .delta. Opioid antagonist activity and binding studies of regioisomeric isothiocyanate derivatives of naltrindole: evidence for .delta. receptor subtypes (1992)
    s.l. : American Chemical Society
    Journal of medicinal chemistry 35 (1992), S. 4086-4091 
    Details
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jm00100a014
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  • 8
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    Review of Brendan O'Leary, "The Asiatic Mode of Production Oriental Despotism, Historical Materialism and Indian History" (Book Review) (1991)
    London : Periodicals Archive Online (PAO)
    Journal of the Economic and Social History of the Orient. 34 (1991) 365 
    Details
    ISSN: 0022-4995
    Topics: Ethnic Sciences , History , Sociology , Economics
    Description / Table of Contents: INDIAN SUBCONTINENT
    Notes: SUBJECTS
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:6133-1991-034-00-000029
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  • 9
    Electronic Resource
    Electronic Resource
    Mutagenic and genotoxic activities of extracts derived from the cooked and raw edible mushroomAgancus bisporus (1990)
    Springer
    Journal of cancer research and clinical oncology 116 (1990), S. 475-479 
    Details
    ISSN: 1432-1335
    Keywords: Agaricus bisporus ; Histidine artefacts ; Genotoxic effects ; Salmonella typhimurium ; Primary rat hepatocytes ; DNA amplification ; Short-term in vivo tests ; micronuclei ; DNA single-strand breaks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A. bisporus has been reported to be carcinogenic to mice [Toth et al. (1986) Cancer Res 38:177–180] and mutagenic inSalmonella typhimurium [Sterner et al. (1982) Mutat Res 101:269–281]. The effects of different heat treatments on the mutagenicity of raw, cooked (boiled) and friedA. bisporus extracts in theS. typhimurium test is reported. The spectrum of potential mutagenic activity ofA. bisporus extracts was tested in vitro in Syrian hamster embryo cells for selective DNA amplification and in primary rat hepatocytes for DNA singlestrand breaks. DNA single-strand breaks were also determined in liver cells of rats and micronuclei were measured in bone marrow cells of mice in vivo following oral application ofA. bisporus extracts. It was shown that the complexA. bisporus extracts per se are not detectably mutagenic inS. typhimurium and that the previously observed increase in number of colonies per plate is probably due to a histidine artefact. No indication of genotoxicity was seen in the two in vitro assays with primary mammalian cells with two different end points. No evidence of in vivo genotoxic effects was observed in the rat liver cells. Finally,A. bisporus was not genotoxic in the micronucleus assay of mouse bone marrow cells in contrast to its previously reported carcinogenicity in mice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01612997
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  • 10
    Electronic Resource
    Electronic Resource
    Allelism of SNQ1 and ATR1, genes of the yeast Saccharomyces cerevisiae required for controlling sensitivity to 4-nitroquinoline-N-oxide an aminotriazole (1990)
    Springer
    Current genetics 18 (1990), S. 93-96 
    Details
    ISSN: 1432-0983
    Keywords: Mutagen resistance ; DNA sequencing ; Transmembrane protein ; Gene disruption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary SNQ1 gene function is required for the expression of resistance to 4NQO in wild-type yeast. The sequence of a 3.7 kb yeast DNA containing the gene SNQ1 was determined. The SNQ1 gene consists of an open reading frame of 1641 bp and encodes, according to the hydrophobicity analysis of the putative protein, a transmembrane protein of 547 amino acids. Homology searches in yeast genome databanks revealed a 100% sequence homology with gene ATR1 which controls resistance to aminotriazole in S. cerevisiae. Pre-treatment of wild-type yeast, but not of snq1-0::LEU2 disruption mutants, with sublethal doses of aminotriazole induced hyper-resistance to 4-nitroquinoline-N-oxide. Partial deletion of the nucleotide sequence coding for a putative ATP-binding site has no, or little, influence on resistance to 4NQO whereas total deletion of the region coding for this ATP-binding domain leads to 4NQO-sensitive nullmutants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00321122
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