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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 108 (1998), S. 2197-2207 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The kinetics of HDO surface and bulk diffusion on ultrathin (25–192 BL; 90–700 Å) single-crystal H216O ice multilayers were studied using a combination of laser-induced thermal desorption (LITD) probing and isothermal desorption depth-profiling. The single-crystal hexagonal ice multilayers were grown epitaxially on a single-crystal Ru(001) metal substrate with the basal (001) facet of ice parallel to the Ru(001) surface. HDO surface diffusion on the single-crystal ice multilayer was not observed within the resolution of the LITD experiment at T=140 K. These LITD surface diffusion experiments yielded an upper limit to the HDO surface diffusion coefficient of Ds≤1×10−9 cm2/s at T=140 K. The bulk diffusion coefficients were measured along the c axis of the hexagonal ice crystal which is perpendicular to the (001) plane. HDO was observed to diffuse readily into the underlying H216O ice multilayer. The measured HDO bulk diffusion coefficients ranged from D=2.2(±0.3)×10−16 cm2/s to D=3.9(±0.4)×10−14 cm2/s over the temperature range from 153 to 170 K. The HDO bulk diffusion coefficients were measured for H216O thicknesses of 25–192 BL (1 BL=1.06×1015 molecules/cm2) and initial HDO adlayer thicknesses of 2–9 BL. The HDO bulk diffusion was independent of H216O film thickness and initial HDO coverage. Arrhenius analysis of the temperature-dependent bulk diffusion coefficients yielded a diffusion activation energy of EA=17.0±1.0 kcal/mol and a diffusion preexponential of Do=4.2(±0.8)×108 cm2/s. Compared with extrapolations from macroscopic diffusion kinetics obtained earlier at temperatures close to the melting point, these bulk diffusion coefficients are larger and may reflect the perturbation of the ultrathin ice films induced by the nearby interfaces. The differences between these HDO diffusion kinetics and recently measured kinetics for H218O indicate that H/D exchange and molecular transport make comparable contributions to the HDO diffusion coefficient. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 54 (1998), S. 1341-1343 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Annals of surgical oncology 5 (1998), S. 33-36 
    ISSN: 1534-4681
    Keywords: Breast ; Lobular carcinoma in situ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: We thought that observation for patients with lobular carcinoma in situ (LCIS) had been generally accepted by the mid-1980s. A questionnaire mailed to oncologic surgeons in 1988 revealed that 33% of the respondents still advised unilateral mastectomy, although a slim majority (54%) advised observation. New studies have been published in the intervening 8 years, and we decided it would be worth recirculating the 1988 questionnaire. Methods: The identical questionnaire was mailed to members of the same oncologic societies (Society of Surgical Oncology [SSO] and Society for the Study of Breast Disease), but changes in membership necessitated new mailing lists. Results: Observation has yet to be universally accepted by the oncologic community, but at this time 85% of the respondents suggest it as the preferred option for their patients. Conclusions: Recent studies have questioned some of the tenets laid down by Haagensen in 1978, but it appears clear that his formulation of LCIS as a marker of increased risk continues to gain ground over the original concept of inevitable progression to invasive disease.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of orthopaedic and trauma surgery 118 (1998), S. 111-112 
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Calcaneal fractures in young children are rare. Bilateral calcaneal fractures in this age group are exceptional. In the literature only 4 cases of bilateral calcaneal fractures have been reported, and the youngest patient was 6 years old (range 6–17 years) [2, 8]. Jonasch [4] estimated that calcaneal fractures accounted for 0.005% of all fractures before the age of 15, in contrast to 1%–2% in adults. This is confirmed by other studies [5, 8, 10]. It is not unlikely that the incidence is indeed higher because the joint involvement in childhood injuries is often subtle, and the fracture can easily be overlooked on initial X-ray examination [7, 8]. We survey the literature and report the case of a 5-year-old boy who sustained bilateral calcaneal fractures and an additional fracture of the neck of the talus on one side, a combination which to our knowledge has never been described before.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cardiovascular drugs and therapy 12 (1998), S. 151-153 
    ISSN: 1573-7241
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of clinical monitoring and computing 14 (1998), S. 89-94 
    ISSN: 1573-2614
    Keywords: Anesthesia ; automatic ; recordkeeping ; medical records ; computers ; human factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine
    Notes: Abstract Objective. To install and successfully use early commercial automatic anesthesia recordkeepers, the Diatek Arkive “Organizer” units, in the operating rooms at a major university medical center. Methods. Because of the history of previous academic attempts at automatic anesthesia recordkeeping, the units were installed on a “surprise” basis, with hardly any discussion of the devices beforehand. Results. The devices themselves had a number of minor difficulties at the start, most of which were promptly corrected. Eventually the units were in use in all non-cardiac general operating rooms. At one point, usage reached over 90% of possible cases. Continued opposition to the device on the part of certain individuals, coupled with the obsolescence of the present devices in light of new technology, led to the eventual abandonment of the system and removal of the devices from service. Discussion. Total resistance to the new devices on the part of a few vocal faculty members was a major factor in the ultimate downfall of the system. The method of introduction, and especially the lack of involvement of faculty, residents, surgeons, operating room personnel, hospital computer personnel, and the hospital administration in the installation also played a role in the failure of the system. Lack of a workable training mechanism for new residents prevented that user group from rapidly gaining comfort with the systems.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 70 (1998), S. 623-626 
    ISSN: 0020-7608
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The leaky aquifer function W(x, y) is an incomplete Bessel function which has had application in hydrology and more recently in electronic-structure calculations. This article presents an expansion which improves the efficiency of the calculation of W in the only part of its range not treated adequately by previously published methods, namely, the regime where x and y are both larger than unity but one is much larger than the other.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 623-626, 1998
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0268-2605
    Keywords: fungicidal activity ; Ceratocystis ulmi ; triphenyltin(IV) ; tributyltin(IV) ; phenolic bridge ; carboxylate bridge ; polymers ; trigonal bipyramidal structures ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methods of synthesis, elemental analysis, IR and NMR spectroscopic data and fungicidal activity against Ceratocystis ulmi are reported for a series of triorganotin esters of N-arylidene-ω-amino acids of general formula R3SnOCO(CH2)nN = CHAr (R = Ph, n-Bu; Ar = 2-HOC6H4, 2-HOC10H6; n = 1, 2, 3 and 5). The crystal structures for two of the compounds, tributyltin N-2-hydroxynaphthalidene glycinate (1) and tributyltin N-2-hydroxynaphthalidene-β-alaninate (2), have been determined. Although both of these compounds have a trans-R3SnO2 structure, in compound 1 the carboxylate group is monodentate and the fifth coordination position around the tin atom is taken up by a coordinated phenolic group, whereas in 2 the carboxylate group is bridging. These two examples thus correspond to the two different structures reported for trans-R3SnO2 complexes. Both compounds were found to be active against Ceratocystis ulmi, but there was no significant difference in their levels of biological activity against this particular fungus. Apart from compound 1, the other tributyltin compounds reported are believed to adopt the carboxylate bridging mode shown by compound (2).Crystal data: for 1, crystals monoclinic, space group P21/c, a = 12.9435(11) Å, b = 13.5769(10) Å, c = 15.7715(12) Å, β = 108.919(6)°, Z = 4, Rf = 0.046 and Rw = 0.058 for 1448 significant reflections; for 2, crystals monoclinic, space group C 2/c,a = 24.588(14) Å, b = 9.733(3) Å, c = 27.611(12) Å,β = 113.49(4)°, Z = 8, Rf = 0.053 and Rw = 0.069 for 3822 significant reflections. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 68 (1998), S. 385-404 
    ISSN: 0020-7608
    Keywords: lattice sums ; Ewald method ; electrostatic energy ; two-dimensional ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This study presents formulas for the electrostatic energy of lattices with two-dimensional periodicity, based on Fourier representations and alternatively on the Ewald procedure for convergence acceleration. The work extends the contributions of previous investigators by taking full advantage of plane-group symmetry and by providing analytical formulas for all derivatives of the energy through second order. The derivatives considered include those with respect to the positions of all charges within the unit cell, those with respect to the lattice vectors (cell deformations), and those involving both types of variables.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 68: 385-404, 1998
    Type of Medium: Electronic Resource
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