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  • 1
    Electronic Resource
    Electronic Resource
    Theoretical study of the nature of the bonding in zirconium and titanium complexes [Cp2M(.mu.-X)]2, where M = Zr (X = I, PH2, and NH) and M = Ti (X = Cl) (1993)
    s.l. : American Chemical Society
    Organometallics 12 (1993), S. 2794-2805 
    Details
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/om00031a055
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  • 2
    Electronic Resource
    Electronic Resource
    Molecular mechanics in organic synthesis (1993)
    s.l. : American Chemical Society
    Chemical reviews 93 (1993), S. 2463-2486 
    Details
    ISSN: 1520-6890
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/cr00023a007
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  • 3
    Electronic Resource
    Electronic Resource
    The embryonic expression pattern of labial, posterior homeotic complex genes and the teashirt homologue in an apterygote insect (1999)
    Springer
    Development genes and evolution 209 (1999), S. 77-90 
    Details
    ISSN: 1432-041X
    Keywords: Key words Thermobia domestica ; Thysanura ; teashirt ; HOM-C ; Insect evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  During embryogenesis of the fruit fly, Drosophila melanogaster, the homeotic genes are required to specify proper cell fates along the anterior-posterior axis of the embryo. We cloned partial cDNAs of homologues of the Drosophila homeotic gene teashirt and five of the homeotic-complex (HOM-C) genes from the thysanuran insect, Thermobia domestica, and assayed their embryonic expression patterns. The HOM-C genes we examined were labial, Antennapedia, Ultrabithorax, abdominal-A and Abdominal-B. As the expression pattern of these HOM-C genes is largely conserved among insects and as Thermobia is a member of a phylogenetically basal order of insects, we were able to infer their ancestral expression patterns in insects. We compare the expression patterns of the Thermobia HOM-C genes with their expression in Drosophila and other insects and discuss the potential roles these genes may have played in insect evolution. Interestingly, the teashirt homologue shows greater variability between Thermobia and Drosophila than any of the HOM-C genes. In particular, teashirt is not expressed strongly in the Thermobia abdomen, unlike Drosophila teashirt. We propose that teashirt expression has expanded posteriorly in Drosophila and contributed to a homogenization of the Drosophila larval thorax and abdomen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050230
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  • 4
    Electronic Resource
    Electronic Resource
    The expression of two engrailed-related genes in an apterygote insect and a phylogenetic analysis of insect engrailed-related genes (1998)
    Springer
    Development genes and evolution 208 (1998), S. 547-557 
    Details
    ISSN: 1432-041X
    Keywords: Key words engrailed ; Thermobia domestica ; Oncopeltus fasciatus ; Dorsal ridge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Homologues of the Drosophila segment polarity gene engrailed have been cloned from many insect species, as well as other arthropods and non-arthropods. We have cloned partial cDNAs of two engrailed homologues, which we call engrailed-related genes, from the phylogenetically basal insect, Thermobia domestica (Order Thysanura) and possibly as many as four engrailed-related genes from the phylogenetically intermediate insect, Oncopeltus fasciatus (Order Hemiptera). Previous to our findings, only single engrailed-related homologues had been found in phylogenetically intermediate insect species (Tribolium and Schistocerca) and in the crustacean Artemia, while two engrailed-related homologues have been found in more derived orders (Hymenoptera and the engrailed and invected genes of lepidopterans and dipterans). Consequently, we performed a phylogenetic analysis of insect engrailed-related genes to determine whether insects ancestrally had one or two engrailed-related genes. We have found evidence of concerted evolution among engrailed-related paralogues, however, that masks the true phylogenetic history of these genes; the phylogeny may only be decipherable, therefore, by examining the presence or absence of engrailed-specific and invected-specific motifs, which will require cloning the full length cDNAs from more species. In addition, we examined the embryonic expression pattern of the two Thermobia engrailed-related genes; like Drosophila engrailed and invected, they are expressed in very similar patterns, but show one temporal difference in pregnathal segments that correlates with the tentative phylogenetic placement of the genes. Thermobia engrailed-related expression also confirms that the dorsal ridge is an ancient structure in insects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050214
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  • 5
    Electronic Resource
    Electronic Resource
    An improved H3 potential energy surface (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 4343-4359 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We report ab initio calculations of the ground state energy for 404 new conformations of H3, supplementing the set of 368 conformations reported previously by others. The entire dataset has been used to constrain an analytical functional form for the potential energy surface, building on that of Truhlar and Horowitz. The new surface extends the Truhlar and Horowitz surface to higher energies and offers some modest improvement at lower energies. In addition, we have eliminated a problem with derivatives of the London equation that was pointed out by Johnson. The new surface matches the 772 ab initio energies with an overall root-mean-square (rms) error of 0.25 mhartree (i.e., 0.16 kcal/mol) and a maximum absolute deviation of 1.93 mhartree (1.21 kcal/mol); for "noncompact'' conformations (no interatomic distance smaller than 1.15 bohr), the rms error is 0.17 mhartree (0.11 kcal/mol) and the maximum absolute deviation is 1.10 mhartree (0.69 kcal/mol). The classical barrier height for H+H2→H2+H is estimated to be 15.20±0.15 mhartree (i.e., 9.54±0.09 kcal/mol).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461758
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical structures and stabilities of allyl and 3,3,3-trifluoro-2-propenyl cations (1991)
    s.l. : American Chemical Society
    The @journal of organic chemistry 56 (1991), S. 575-580 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00002a018
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  • 7
    Electronic Resource
    Electronic Resource
    A refined H3 potential energy surface (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 7139-7152 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In evaluating some low temperature (T〈1000 K) thermal rate coefficients for inelastic rotational excitation of H2 by H atoms, Sun and Dalgarno have found a marked sensitivity to the potential energy surface adopted for the calculations. We have investigated the origin of the discrepancies between previous H3 potential energy surfaces and have developed a refined surface which addresses these concerns. New quasiclassical trajectory calculations of cross sections for low energy rotational excitation are reported. The refined surface is based on 8701 ab initio energies, most newly computed for this purpose. It has the same functional form as our earlier (BKMP) surface, but since the fit of the parameters is more fully constrained than for any previous surface it is a more accurate representation. The refined surface matches the ab initio energies with an overall rms error of 0.27 mEh (i.e., 0.17 kcal/mol) and a maximum absolute deviation of 6.2 mEh (for a very compact high energy equilateral triangle conformation). For "noncompact'' conformations (no interatomic distance smaller than 1.15 bohr), the rms error is 0.18 mEh and the maximum absolute deviation is 1.7 mEh. The refined surface is compared critically to four previous surfaces, including the DMBE surface of Varandas et al., in several respects: Legendre expansion coefficients; the interaction region for low energy rotational excitation; near the collinear saddle point; near conical intersections of the ground and first excited state surfaces; the van der Waals well; and compact geometries. We have also compared new first excited state ab initio energies for 1809 conformations with corresponding predictions from the DMBE surface. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471430
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  • 8
    Electronic Resource
    Electronic Resource
    Accurate ab initio potential energy computations for the H4 system: Tests of some analytic potential energy surfaces (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 4331-4342 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The interaction potential energy surface (PES) of H4 is of great importance for quantum chemistry, as a test case for molecule–molecule interactions. It is also required for a detailed understanding of certain astrophysical processes, namely, collisional excitation and dissociation of H2 in molecular clouds, at densities too low to be accessible experimentally. Accurate ab initio energies were computed for 6046 conformations of H4, using a multiple reference (single and) double excitation configuration interaction (MRD-CI) program. Both systematic and "random'' errors were estimated to have an rms size of 0.6 mhartree, for a total rms error of about 0.9 mhartree (or 0.55 kcal/mol) in the final ab initio energy values. It proved possible to include in a self-consistent way ab initio energies calculated by Schwenke, bringing the number of H4 conformations to 6101. Ab initio energies were also computed for 404 conformations of H3; adding ab initio energies calculated by other authors yielded a total of 772 conformations of H3. (The H3 results, and an improved analytic PES for H3, are reported elsewhere.) Ab initio energies are tabulated in this paper only for a sample of H4 conformations; a full list of all 6101 conformations of H4 (and 772 conformations of H3 ) is available from Physics Auxiliary Publication Service (PAPS), or from the authors.The best existing analytic PESs for H4 are shown to be accurate only for pairs of H2 molecules with intermolecular separations greater than about 3 bohr (1.6 A(ring)). High energy collisions (such as might lead to direct collisional dissociation) cannot be well represented by such surfaces. A more general analytic PES for H4 is required, which will be accurate for compact (high-energy) conformations and for conformations that cannot be subdivided into a pair of H2 molecules. Work in progress on devising such a surface (fitted to the 6101 conformations of this work) will be reported in a forthcoming paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461757
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  • 9
    Electronic Resource
    Electronic Resource
    Family History Status as a Prognostic Factor for Breast Cancer Patients Treated with Conservative Surgery and Irradiation (1995)
    Oxford, UK : Blackwell Publishing Ltd
    The @breast journal 1 (1995), S. 0 
    Details
    ISSN: 1524-4741
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: From 1977 to 1986, 264 women with stage I or II breast cancer and positive breast cancer family histories were treated with conservative surgery, axillary dissection, and irradiation. The records of these cases were reviewed and compared to those of 517 women with stage I or II breast cancer and negative breast cancer family histories who were treated similarly during the same time period. Patients with a negative family history were more likely to present with positive axillary lymph nodes than patients whose history was positive (33% vs. 26.5%, p = 0.054). There were no statistically significant differences found between the family history positive and family history negative women in terms of 5 and 10 year actuarial overall survival (5 yr: 91% vs. 90%, 10 yr: 86% vs. 82%) or relapse-free survival (5 yr: 76% vs. 76%, 10 yr: 64% vs. 61 %). Breast recurrence rates were likewise not significantly different for the two groups of patients (5 yr: 6% vs. 9%, 10 yr: 17% vs. 18%). A separate analysis restricted to lymph node-positive patients revealed no significant differences in survival between the family history positive and family history negative groups. It thus appears that women with early stage breast cancer who have a family history of the disease can be treated with breast-conserving surgery and definitive irradiation with the same excellent results as seen in women without such a family history.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1524-4741.1995.tb00241.x
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  • 10
    Electronic Resource
    Electronic Resource
    Modeling the Potential Impacts of Different Radon Policies for the U.S. Housing Stock (1995)
    Oxford, UK : Munksgaard International Publishers
    Indoor air 5 (1995), S. 0 
    Details
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: According to the Environmental Protection Agency (EPA) and other public health agencies in the United States, radon may be the leading cause (along with passive smoking) of lung cancer deaths among nonsmokers. Radon is estimated to be the second leading cause of lung cancer death in smokers behind smoking-related lung cancer. EPA estimates that 7,000 to 30,000 lung cancer deaths each year are due to radon exposure. (It is implied that radon-related lung cancer deaths can be prevented by reducing radon levels below EPA's guideline levels.) Current EPA radon policy is based on a strategy of education, the transfer of testing and remediation technologies to the public and private sectors, and recently proposed radon-resistant construction standards for new homes. This paper models the effectiveness of current, proposed, and alternative policies for reducing radon risks in U.S. residential construction. The results of our analysis suggest that EPA's projections of 2,200 “lives saved annually” as a result of its current action level of 4 pCi/l will not be achieved with its current policy in the near future. Overall, the response of radon-related mortality to most policy options is delayed and flat due in pan to the large number of houses with low radon levels and the long latency period between radon exposure and the development of cancer. The modeling results suggest that more aggressive smoking reduction programs may yield greater benefits in overall lung cancer mortality (but not reduced radon exposure) than most radon-related policies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0668.1995.t01-2-00006.x
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