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  • 1
    Electronic Resource
    Electronic Resource
    Flow distribution in the fiber lumen side of a hollow-fiber module (1986)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 32 (1986), S. 1937-1947 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Little attention has been paid to the flow distribution among many thousands of fibers in the hollow-fiber modules of artificial kidney, ultrafiltration, and reverse osmosis devices despite its potential importance in the efficiency of the module. Numerical study by a finite-difference method, as well as experiment by direct sampling from individual fibers and high-speed photography of a color tracer, has shown that there exists a significant degree of nonuniformity in the flow distribution, which depends on the manifold design, the Reynolds number, and the pressure drop along the fibers.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690321202
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  • 2
    Electronic Resource
    Electronic Resource
    Microencapsulation of recombinant Saccharomyces cerevisiae cells with invertase activity in liquid-core alginate capsules (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 51 (1996), S. 157-162 
    Details
    ISSN: 0006-3592
    Keywords: calcium-alginate capsules ; microencapsulation ; invertase ; recombinant Saccharomyces cerevisiae ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: As a means of integrating cell growth and immobilization, recombinant Saccharomyces cerevisiae cells with invertase activity were immobilized in liquid-core alginate capsules and cultured to a high density. S. cerevisiae cells of SEY 2102 (MAT α ura3-52 leu2-3, 112 his4-519) harboring plasmid pRB58 with the SUC2 gene coding for invertase were grown to 83 g/L of liquid-core volume inside the capsule on a dry weight basis. The cloned invertase was expressed well in the immobilized cells with slightly higher activity than the free cells in a batch culture. Invertase in the immobilized cells showed slightly more improved thermal stability than in the free cells. Storage in a Na-acetate buffer at 4°C and 10°C for 1 month resulted in 7% and 8% loss in activity, respectively. The sucrose hydrolysis reaction was stably maintained for 25 repeated batches for 7 days at 30°C. Continuous hydrolysis of 0.3 M sucrose was carried out in a packed bed reactor with a conversion of more than 90% at a maximum productivity of 55.5 g glucose/L per hour for 7 days. In a continuous stirred tank reactor, the maximum productivity of 80.8 g glucose/L per hour was achieved at a conversion of 59.1% using 1.0 M sucrose solution, and 0.5 M sucrose solution was hydrolyzed for 1 week with a 95% conversion at a productivity of 48.8 g/L per hour. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Nucleotides. Part XXXVIPart XXXV:[1]. Syntheses and biological characterization of phosphorothioate analogues of (3′-5′)adenylate trimer (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 892-898 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The four protected diastereoisomcrs 7a/7b and 8a/8b P-thioadenylyl-(3′-5′)-P-thioadenylyI-(3′-5′)-adenosine were synthesized, separated, and deblocked to the free oligonucleotides (Scheme). Biochemical characterization of these (3′-5′)phosphorothioate analogues of adenyiate trimer indicate that these compounds, and the corresponding 5′-monophosphates, neither bind to nor activate RNase L, and are considered to be valuable control compounds in screening experiments.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740420
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  • 4
    Electronic Resource
    Electronic Resource
    Nucleotides. Part IL.Part XLVIII: [1]. Synthesis and Characterization of Cordycepin-Trimer-Vitamin and -Lipid Conjugates Potential Inhibitors of HIV-1 ReplicationDedicated to Prof. Dr. Richard Neidlein on the occasion of his 65th birthday (1996)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 79 (1996), S. 619-633 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of biodegradable 2′- and 5′ -ester and 2′- and 5′ -carbonate conjugates of the antivirally active 3′-deoxyadenylyl-(2′-5′)-3′-deoxyadenylyl-(2′-5′)-3′-deoxyadenosine (cordycepin-trimer core) with the vitamins, E, D2, and A and the lipids 1,2-di-O-palmitoylglycerol and 1,2-di-O-hexadecylglycerol were achieved first by preparation of the trimeric educts 19-21 (Scheme 1). Secondly, these substances were condensed with the lipophilic residues via a succinate or carbonate linker and then deprotected by β-elimination of the npeoc and npe protecting groups and acid treatment for detritylation without harming the ester and carbonate functions, respectively (Scheme 2). Metabolically stable cordycepin-trimer-vitamin and -lipid conjugates are a new class of bioconjugates that inhibit HIV-1-induced syncytia formation with IC50 values of 7, 18, and 24 m̈M for 39, 29, and 42, respectively, and inhibit HIV-1 reverse transcriptase (RT) activity from 14 to 96% (see Table). Of the nine conjugates tested, inhibition of HIV-1 replication by 28, 29, 32, 40, and 42 may be attributed in part to the activation of the RNase L/PKR antiviral pathways. Trimer conjugate 42 showed the greatest inhibition of HIV-1 replication, i.e., a 120-fold decrease in HIV-1-induced syncytia formation and an 88% inhibition of HIV-1 reverse transcriptase (RT). This inhibition of replication of HIV-1 by 42 can be attributed in part to the activation of recombinant, human RNase L. The inhibition of HIV-1 replication by the cordycepin-trimer-vitamin and -lipid conjugates is significantly greater than that observed for the (2′-5′) A-trimer core or cordycepin-trimer core.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19960790305
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  • 5
    Electronic Resource
    Electronic Resource
    Nucleosides. Part LX.Part LIX: [1]. Synthesis and Characterization of Monomeric Cordycepin-Vitamin and Cordycepin-Lipid Conjugates Model Substances for Biodegradable Ester and Carbonate Linkages in Conjugates and Potential Inhibitors of HIV-1 ReplicationDedicated to Prof. Dr. h. c. Hans-Jürgen Bestmann on the occassion of his 70th birthday and in admiration to his interesting contribution to organic chemistry (1996)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 79 (1996), S. 609-618 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomeric 3′-deoxyadenosine (cordycepin) was modified at the 2′-O- (13-18) and 5′-O-position (25-29) by the vitamins E, D2, and A and by the two lipids 1,2-di-O-palmitoylglycerol and 1,2-di-O-hexadecylglycerol via succinate or carbonate linkages. The base-labile conjugates afforded protection groups like the 2-(4-nitro-phenyl)ethoxycarbonyl (npeoc) and monomethoxytrityl group (MeOTr) that are cleavable without harming the ester and carbonate bonds, respectively. Monomeric conjugates of cordycepin and vitamin E, vitamin D2, 1,2-di-O-palmitoylglycerol, and 1,2-di-O-hexadecylglycerol (see 13, 14, 17, 18, 25, 26, 28, and 29) inhibited HIV-1-induced syncytia formation 1.7 to 6.2 fold compared to 1.5-fold for cordycepin (see Table); IC50 values for 25 and 28 were 257 and 267 m̈M, respectively. In addition, the monomeric cordycepin-vitamin and -lipid conjugates inhibited HIV-1 RT activity 28-49% which compares with a 13% inhibition of HIV-1 RT observed for cordycepin. The minimal inhibition of HIV-1-induced syncytia formation and HIV-1 RT activity did not proceed by the activation of RNase L. The monomeric conjugates tested (13, 14) increased PKR expression.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19960790304
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  • 6
    Electronic Resource
    Electronic Resource
    Nucleotides. Part LIIIPart LII: [1].. 6-Aminohexanoyl-linked conjugates of monomeric and trimeric cordycepin (1997)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 80 (1997), S. 1061-1072 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To improve cell permeability, monomeric 3′-deoxyadenosine (cordycepin) and antivirally active trimeric 3′-deoxyadenylyl-(2′-5′)-3′-deoxyadenylyl-(2′-5′)-3′-deoxyadenosine (2′-5′)d3 (A-A-A); (cordycepin-trimer core) were modified at the 2′-O- or 5′-O-position by myristic, cholic, and folic acid = tetradecanoic, 3α, 7α, 12α -trihy-droxy-5β-cholan-24-oic, and N-{4-{[(2-amino-3,4-dihydro-4-oxopteridin-6-yl)methyl]amino}benzoyl}-L-glutamic acid, resp., linked by a 6-aminohexamoyl spacer. Syntheses of the trimeric educts 21, 27, and 28 were performed by phosphoramidite chemistry, using β-eliminating 2-(4-nitrophenyl)ethyl (npe), 2-(4-nitrophenyl)ethoxycarbonyl (npeoc) and (9H-fluoren-9-yl)methoxycarbonyl (fmoc) groups which allow a deprotection by DBU in an aprotic solvent without harming the ester-bounded conjugates, to give the products 24-26 and 31-33. The metabollically stable (2′-5′)A derivatives 26 and 33, covalently linked to folic acid either at the 2′-terminus or at the 5′-terminus of (2′-5′)d3′(A-A-A), respectively, are a new class of the anti-HIV-1 compounds. Inhibition of HIV-1 reverse transcriptase (RT) activity by 26 and 33 was 45 and 81%, respectively. Only 33 activated recombinant, human RNase L by 35%.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19970800405
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  • 7
    Electronic Resource
    Electronic Resource
    A theoretical study on keto-enol tautomerization involving simple carbonyl derivatives (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 18 (1997), S. 56-69 
    Details
    ISSN: 0192-8651
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The relative stabilities of the keto and enol forms [Δ E0 (enol-keto)] and the energy barriers to enolization of the keto forms [Δ E≠ (transition state-keto)] for CH3COR (R = CH3, H, F, and CN) and CH3CHY (Y = CH2, NH, and S) are investigated theoretically by Hartree-Fock and Möoller-Plesset second-order calculations with 6-31G** basis sets. Specific and bulk solvent effects are considered by incorporating one water molecule and applying the self-consistent reaction field (SCRF) method to the reaction system, respectively. The Δ E0MP2 values are all positive, in agreement with the lower stability of the enol form in the gas phase as well as in solution. In contrast to a relatively small effect of specific as well as bulk solvation on Δ E0, there is a large lowering of Δ E≠ (by ca. 30 kcal/mol) when solvent effects are accounted for. In general, both Δ E0 and Δ E≠ are depressed in solution and hence enolization is favored thermodynamically as well as kinetically. The keto form is strongly stabilized by a π donor, whereas the enol isomer is stabilized by a π as well as a σ-acceptor substituent, R. As a result, substituent R = F is the most unfavorable whereas R = CN is the most favorable for the enolization. The water catalyzed enolization in the neutral water proceeds concertedly, but carbon deprotonation is more important than carbonyl-oxygen protonation by water in the rate determining step. © 1997 by John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Ab initio studies of three-membered ring formation through intramolecular nucleophilic substitution (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 18 (1997), S. 1773-1784 
    Details
    ISSN: 0192-8651
    Keywords: three-membered ring formation ; intramolecular nucleophilic substitution ; ab initio molecular orbital method ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Three-membered ring (3MR) forming processes of -X(SINGLE BOND)CH2(SINGLE BOND)CH2(SINGLE BOND)F and -CH2(SINGLE BOND)C((SINGLE BOND)Y)(SINGLE BOND)CH2(SINGLE BOND)F (X(DOUBLE BOND)CH2, O, or S and Y(DOUBLE BOND)0 or S) through a gas phase neighboring group mechanism (SNi) are studied theoretically using the ab initio molecular orbital method with the 6-31+G* basis set. When electron correlation effects are considered, the activation (ΔG≠) and reaction energies (ΔG0) are lowered by ca. 10 kcal mol-1, indicating the importance of the electron correlation effect in these reactions. The contribution of entropy of activation (-TΔS≠) at 298 K to ΔG≠ is very small, and the reactions are enthalpy controlled. The ΔG≠ and ΔG0 values for these ring closure processes largely depend on the stabilities of the reactants and the heteroatom acting as a nucleophilic center. The Bell-Evans-Polanyi principle applies well to all these reaction series.   © 1997 John Wiley & Sons, Inc.   J Comput Chem 18: 1773-1784, 1997
    Additional Material: 6 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Diffusion of radioactively tagged penetrants through random and block styrene-butadiene copolymers and filled cis-polybutadiene (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 467-476 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The diffusion of radioactively tagged n-hexadecane in trace amounts has been studied in 22 random styrene-butadiene (SBR) copolymers with different styrene contents and butadiene microstructures; in several SBR block copolymers with different average block lengths (also diffusion of tagged 1,1-diphenyl ethane); in a triblock SBR copolymer cast from different solvents and also molded at elevated temperature; and in cis-polybutadiene filled to different extents with carbon black, calcium carbonate, and microglass spheres. The diffusion coefficient in random SBR copolymers decreased with increasing content of styrene and/or vinyl configuration and could be correlated with fractional free volume on the basis of linear additivity of the cis, trans, vinyl, and styrene moieties. In SBR block copolymers, the diffusion coefficient increased with increasing average block sequence length. For the triblock copolymer, the diffusion coefficient was approximately the same for samples molded or cast from solvents which are good for polybutadiene, but was far smaller for a sample cast from ethyl acetate, in which the polystyrene domains are probably lamellar. The effect of fillers on diffusion in cis-polybutadiene was compared with calculations on the basis of several theoretical models.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210213
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  • 10
    Electronic Resource
    Electronic Resource
    Diffusion of radioactively tagged penetrants through rubbery polymers. I. Penetrants with very low solubility (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 773-781 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The diffusion of radioactively tagged n-hexadecane, 1,7-heptanediol, and ethylene glycol has been studied in one polar and six nonpolar rubbery polymers. The penetrant-polymer pairs included some in which the two components were miscible in all proportions and some in which they were nearly incompatible (solubility of penetrant in polymer of the order of 1%). The theory for the thin smear method for measuring the diffusion coefficient was evaluated for incompatible pairs with two cases: case 2, when the rate-limiting step is diffusion through the polymer; and case 3, when the rate-limiting step is entry into the polymer across the penetrant-polymer interface. They are easily distinguished experimentally from each other and from case 1, which refers to completely miscible pairs. In examples of case 3, e.g., ethylene glycol with butadiene or styrene-butadiene rubbers, the half-time for saturating the polymer surface in contact with the penetrant was found to be several days at 25°C. The diffusion coefficients, when compared in four hydrocarbon rubbers, of n-hexadecane and 1,7-heptanediol were similar in magnitude even though in each rubber the hexadecane was soluble in all proportions and the diol only very slightly. The diffusion coefficient of ethylene glycol, despite its extreme thermodynamic incompatibility, appeared to be somewhat larger than those of the other penetrants.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210317
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