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  • 1
    Electronic Resource
    Electronic Resource
    Preparation and structure of (calix[8]arene methyl ether) · 2CDCl3 (1986)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 4 (1986), S. 247-253 
    Details
    ISSN: 1573-1111
    Keywords: calix[8]arene ; crystal structure ; CDCl3 guest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The methyl ether of calix[8]arene crystallizes from CDCl3 with two molecules of the solvent per molecule of host. An X-ray structural investigation has shown that the CDCl3 guests exist within the calixarene framework. The complex resides on a crystallographic center of inversion, and the cavity is roughly circular in projection as measured by the distance between centroids of aromatic rings related by the center: 14.5, 13.9, 10.1, and 11.2 Å. Six of the oxygen atoms are found on the inside and two on the outside. Crystals belong to the triclinic space group $$P\bar 1$$ witha=11.741(9),b=11.810(9),c=12.484(8) Å, α=94.74(8), β=104.41(8), γ=111.30(9)°, andD c =1.31 g cm−3 forZ=1. Refinement led to a finalR value of 0.086 for 949 observed reflections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00657998
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  • 2
    Electronic Resource
    Electronic Resource
    Reaction of trimethylaluminum with calixarenes. I. Synthesis and structure of [Calix[8]arene methyl ether] [AlMe3]6·2 toluene and of [p-tert-butylcalix[8]arene methyl ether] [AlMe3]6·4 benzene (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 581-590 
    Details
    ISSN: 1573-1111
    Keywords: Calix[8]arene ; crystal structure ; AlMe3 ; aromatic adduct
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reaction of the methyl ether of calix[8]arene with AlMe3 yields [calix[8]arene methyl ether] [AlMe3]6·2 toluene,1, while that ofp-tert-butylcalix[8]arene gives [p-tert-butylcalix[8]arene methyl ether] [AlMe3]6·4 benzene,2. Both compounds1 and2 fail to react with alkali metal salts, MX. In1, the absence of a butylpara-substituent affords greater flexibility than is the case for thetert-butyl compound2. Thus, all six of the AlMe3 groups are located on the outside of the macrocyclic ring (in projection) in1, but two AlMe3 units are found on the inside in2. Colorless, air-sensitive crystals of1 belong to the triclinic space group $$P\bar 1$$ witha=13.690(8),b=14.317(4),c=14.738(6) Å, α=76.11(3), β=62.36(4), γ=82.41(4)o, andD c =1.06 g cm−3 forZ=1. Refinement led toR=0.101 for 1154 observed reflections.2 crystallizes in $$P\bar 1$$ with α=12.400(6),b=16.229(8),c=19.251(5) Å, α=96.17(3), β=107.25(3), γ=101.54(3)o, andD c =1.01 g cm−3 forZ=1. Refinement of2 gaveR=0.128 for 4351 observed reflections. The macrocyclic array in both1 and2 lies about a crystallographic center of inversion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662997
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  • 3
    Electronic Resource
    Electronic Resource
    Alternative methods of modifying the calixarene conformation. The synthesis and molecular structures oft-butylcalix[4]arene methyl ether complexed with aluminum alkyl species (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 747-758 
    Details
    ISSN: 1573-1111
    Keywords: Calix[4]arene ; aluminum alkyl ; crystal structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The configurations of calix[4]arenes may be modified by the formation of donor-acceptor complexes which make use of the basicity of the oxygen atoms of the macrocycle. The complex [t-butylcalix[4]arene methyl ether][AlMe3]2,2, exhibits the previously unseen ‘1,2-alternate’ geometry, while [t-butylcalix[4]arene methyl ether][MeAlCl2]2,3, and [t-butylcalix[4]arene methyl ether][EtAlCl2]2,4, show the ‘1,3-alternate’ configuration.2 crystallizes in the triclinic space groupPl witha=11.14(1),b=11.60(1),c=12.02(1) Å, α=77.32(8), β=67.91(8), and γ=69.34(8)o withD c =1.06 g cm−3 forZ=1. Refinement based on 1270 observed reflections led toR=0.106.3 as the benzene solvate belongs to the monoclinic space groupC2/c witha=12.116(2),b=21.557(7),c=23.470(6) Å, and β=104.05(2)o withD c =1.13 g cm−3 forZ=4. Refinement based on 2335 observed reflections led toR=0.075.4 crystallizes in the monoclinic space groupC2/c witha=12.062(4),b=21.175(6),c=21.596(5) Å, and β=100.78(4)o withD c =1.18 g cm−3 forZ=4. Refinement based on 2529 observed reflections gaveR=0.082. The Al-O lengths in all three complexes are normal for donor-acceptor interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656595
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  • 4
    Electronic Resource
    Electronic Resource
    Organic clays. Synthesis and structure of Na5[calix[4] arene sulfonate] · 12 H2O, K5[calix[4]arene sulfonate]·8 H2O, Rb5[calix[4]arene sulfonate]·5 H2O, and Cs5[calix[4] arene sulfonate] ·4 H2O (1989)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 7 (1989), S. 203-211 
    Details
    ISSN: 1573-1111
    Keywords: Calix[4]arene ; crystal structure ; clay mineral ; alkali metal ion ; layered structure ; water soluble ; sulfonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The title calixarenes all exist in the solid state as bilayers of anionic calixarenes in the cone configuration. These layers alternate with inorganic regions which contain the cations and the water molecules. The overall structures bear a close resemblance to those found for clay minerals. The sodium salt crystallizes in the triclinic space groupPĪ witha = 10.998(6),b = 13.582(5),c = 14.472(5) Å,α = 74.01(3),β = 89.09(4),γ = 86.50(4)°, andZ = 2 forD calc = 1.72 g cm−3. Refinement based on 4727 observed reflections led to a conventionalR = 0.050. The potassium salt crystallizes in the triclinic space groupPĪ witha = 11.815(9),b = 13.636(6),c = 14.040(9) Å,α = 100.24(5),β = 111.86(9),γ = 95,14(9)°, andZ = 2 forD calc = 1.77 g cm−3. Refinement based on 2977 observed reflections led toR = 0.15. The rubidium and cesium salts are isostructural and crystallize in the monoclinic space groupP21/n with parameters for Rb[Cs]a = 11.603(5) [11.704(3)],b = 28.607(8) [29.747(9)],c = 12.512(5) [12.604(4)] Å,β = 91.70(4) [91.63(2)°], andZ = 4 forD calc = 2.01 [2.24] g cm−3. Refinement based on 1750 [4257] observed reflections led toR = 0.108 [0.075]. Disorder of the cations was observed for the rubidium and cesium salts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01060722
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  • 5
    Electronic Resource
    Electronic Resource
    On the rheology of cold drawing. I. Elastic materialsDedicated to Hershel Markovitz on the occasion of his retirement from Carnegie Mellon. (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1801-1822 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this, the first paper in a series on neck formation and steady-state drawing of polymeric fibers and films under uniaxial tension, the emphasis is laid on those aspects of the mechanics of cold drawing that are not sensitive to viscoelastic effects and, therefore, can be treated by use of constitutive assumptions appropriate to elastic materials. It is here shown that a unidimensional theory which has been employed to model the mechanics of slender bars in tension6 can be derived as an approximation for three-dimensional bars and, in a sense which can be made precise, is valid to within an error of the order of the fourth power of the thickness. A particular constitutive equation for incompressible, three-dimensional, elastic materials is explored in detail and is found to yield, for such slender bars as thin fibers and wide (but thin) strips of film, equations of equilibrium whose solutions are in good qualitative accordance with the necks and drawing configurations observed in practice.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260901
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  • 6
    Electronic Resource
    Electronic Resource
    Adsorption of low density lipoproteins onto selected biomedical polymers (1987)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 21 (1987), S. 683-700 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: This study examines the interaction of human low density lipoprotein (LDL) with a select group of biomedical polymers. The adsorption characteristics of LDL on cured filler-free poly(dimethyl Siloxane) (C-PDMS), Biomer, Cardiomat 610, Kraton 1650, poly(hydroxyethyl methacrylate) (PHEMA) and glass are presented. Adsorption of LDL to charged hydrophilic glass control surfaces occurred rapidly, reaching plateau concentrations within one minute (0.19 ± 0.01 ug/cm2). Adsorption of LDL to polymer surfaces appeared to be dependent upon both the polymer hydrophobicity (or apolar nature), and flexibility (or dynamic nature) at the interface. Increased surface concentrations were observed for Biomer (0.32 ± 0.01 ug/cm2) as well as other polymers which exhibited both hydrophobic and elastomeric próperties. Temperature changes between 25°C and 37°C were found to significantly influence the surface concentration of LDL on Biomer (0.16 ± 0.01 ug/cm2 at 25°C versus 0.32 ± 0.01 ug/cm2 at 37°C). A lipid core phase transition at 36°C was believed to be responsible for the temperature influence. Preliminary competitive adsorption studies of LDL with albumin (HSA) and serum on silicone surfaces suggests that LDL adsorption occurred rapidly and preferentially (0.25 ± 0.01 ug/cm2 for LDL alone; 0.33 ± 0.01 ug/cm2 for LDL + HSA; 0.15 ± 0.01 ug/cm2 LDL + serum). Preliminary studies on the role of LDL in calcification were not conclusive. It can be concluded that LDL adsorption is dependent upon polymer hydrophobicity, flexibility and temperature. Competitive adsorption experiments suggests that LDL may have substantial influence on protein adsorption.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820210602
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  • 7
    Electronic Resource
    Electronic Resource
    Retrieval and analysis of a clinical total artificial heart (1986)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 20 (1986), S. 417-431 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Examination by light microscopy, scanning electron microscopy (SEM), and x-ray microanalysis of a clinical total artificial heart (TAH) implanted for 112 days revealed no evidence of calcification, pannus, or vegetative thrombus. A macroscopic thrombus was seen along the suture line in the right atrium but did not obstruct blood flow or valve function. Microscopic thrombi (〈0.1 mm) and evidence of microemboli were observed on the pumping diaphragm using SEM. Characterization of selected polyetherurethane (PEU) samples from the pumping bladders and housing by Curie-point pyrolysis mass spectrometry (Py-MS) revealed unexpected differences between postmortem retrieved ventricles. Although the origin of these differences could be traced back to batch-to-batch variations in the original PEU material (Biomer), the precise nature of the observed differences in chemical structure and/or composition is still unknown. Numerical comparison between pyrolysis mass spectra from PEU samples exposed to blood or tissue and unexposed samples from the same ventricles did not detect evidence of biodegradation. Continual improvements in fabrication and quality control should minimize surface imperfections and ensure polymer reproducibility; however, existing materials and design parameters appear to be adequate for continued clinical implantation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820200402
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  • 8
    Electronic Resource
    Electronic Resource
    Evaluation of anti-inflammatory agents using a model of granuloma formation evoked by divinyl copolymer beads in the mouse lung (1986)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 20 (1986), S. 301-314 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: We have developed and quantitated a reproducible standardized granulomatous inflammatory reaction using divinyl copolymer beads. Approximately 10000 gas sterilized beads (43-53 μm in diameter) are injected into the tail veins of mice and embolize to the lungs where they evoke granuloma formation which is maximal at 48 h. The anti-inflammatory effects of both steroidal and nonsteroidal agents, namely, bacterial levan, hydrocortisone acetate, polyanetholsulfonate, indomethacin, acetylsalicylic acid, ellagic acid, and aminophylline were determined by comparing granuloma size in treated animals with those in untreated controls. Granulomas in paraffin sections were traced on the ground glass screen of a light microscope and the area of each granuloma measured with a digitizer-computer programmed to prepare histograms and merge data from replicate experiments. Of the agents tested, the greatest reductions in granuloma size occurred after treatment with bacterial levan (71%), hydrocorticone (70%), polyanetholsulfonate (58%), and indomethacin (55%).
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820200304
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  • 9
    Electronic Resource
    Electronic Resource
    FDA - Medical device news corner (1988)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 119-123 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820221304
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