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  • 1
    Electronic Resource
    Electronic Resource
    Glucose tolerance in two unacculturated Indian tribes of Brazil (1982)
    Springer
    Diabetologia 23 (1982), S. 90-93 
    Details
    ISSN: 1432-0428
    Keywords: Oral glucose tolerance ; plasma insulin ; growth hormone ; pancreatic polypeptide ; Amerindian tribes ; Marubo ; Yanomama
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Plasma levels of glucose, insulin, growth hormone, and pancreatic polypeptide in response to a standard oral glucose load were studied in the Yanomama and the Marubo, two relatively unacculturated Amerindian tribes of the Brazilian Amazon. The findings in the two tribes differed significantly from each other and in the degree of deviation from control subjects. The average responses in both tribes differed significantly from those of age- and sex-matched Caucasoid control subjects studied in Ann Arbor, Michigan; however, of the two tribes, the Marubo, the more acculturated group, resembled the controls more closely. Plasma concentrations of glucose and the hormones at three time points (fasting, 1 h, 2 h) were compared by means of a multivariate analysis. When the Marubo were compared with the control subjects, the only highly significant difference was in the plasma glucose concentrations (all three points were higher in the Marubo); however, the Yanomama differed significantly from the control subjects with respect to all four plasma indicators (p 〈 0.05). Unlike the Marubo, the Yanomama showed no significant rise in plasma glucose at 1 h and no decrease at 2 h. Neither tribe exhibited the bimodality of the 2 h glucose value characteristic of acculturated Amerindians, such as the Pima, but the samples studied were small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01271166
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  • 2
    Electronic Resource
    Electronic Resource
    Internal hernia. Report of nine cases (1997)
    Springer
    Hernia 1 (1997), S. 143-145 
    Details
    ISSN: 1248-9204
    Keywords: Internal hernia ; Winslow's foramen ; Small bowel obstruction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Internal abdominal hernias are rare and develop when one or more viscera protrude through an intraperitoneal orifice while remaining within the peritoneal cavity. This orifice may be normal (Winslow's foramen) or paranormal (peritoneal fossae); these hernias possess a sac and are true hernias. Protrusion may be through a pathologic hole, without a sac, realizing an internal prolapse or procidentia. The clinical diagnosis is always difficult and leads to an urgent operation for intestinal obstruction. The treatment is often simple and the results are generally excellent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02426421
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  • 3
    Electronic Resource
    Electronic Resource
    Etude, par spectroscopie infra-rouge, de la conformation de quelques composés peptidiques modèles (1969)
    New York : Wiley-Blackwell
    Biopolymers 8 (1969), S. 69-89 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some experimental data are given on the infrared spectra between 3300 and 3500 cm-1 of dilute solutions in carbon tetrachloride of three types of model compounds: CH3-CONH-CH(R1)-CONH(R2), (I); CH3-CON(CH3)-CH(R1)-CONH(R2), (II) and CH3-CONH-CH(R1)-CON(R2)2, (III). In studying the N-H stretching bands, it was found that there are two types of intramolecular hydrogen bonds in these molecules; these result in two different cyclized conformations, C5 and C7, which contain respectively, five and seven atoms in the ring. By using model substances I, II, and III, in which the nitrogen atoms are unequally substituted, it is possible to identify the N-H stretching bands which are to be ascribed to the N-H oscillators included in the two different chelated conformations. It is found also that the stretching frequency of a free N-H oscillator depends upon the substituent on the nitrogen atom. Thus, it is possible to observe, with some of the model compounds I, four different absorption bands located at 3340, 3420, 3440, and 3460 cm-1. The first two are ascribed to the N-H oscillators included in the H—bonds which lock the C7 and C5 conformations; the last two correspond to free N-H which differ with the substituent on the nitrogen atom.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1969.360080107
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  • 4
    Electronic Resource
    Electronic Resource
    Experimental and theoretical investigations on the folding modes of depsipeptide molecules (1977)
    New York : Wiley-Blackwell
    Biopolymers 16 (1977), S. 1033-1052 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coupling of N-acyl-α-amino-acids with α-hydroxyacid-methyl amides results in depsipeptide molecules containing two chiral centers and one ester function inserted between two amide functions. Their conformational features have been investigated by IR spectroscopy, proton magnetic resonance, X-ray diffraction, and theoretical P.C.I.L.O. calculations.It is shown that most of these molecules are folded by an intramolecular 4 → 1 hydrogen bonding. Two folded conformations, similar to the well known β turn in peptides, are described, the stability of which depends on the configurational sequence in the investigated molecule.LL and LD species are folded in two different ways whereas LG sequences containing an achiral hydroxy-acid residue accommodate both of them. The presence of a N-terminal achiral amino acid noticeably decreases the folding ratio.The above conclusions are then compared with the conformational features of homologous tripeptide molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1977.360160507
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  • 5
    Electronic Resource
    Electronic Resource
    Liquid transport through membranes prepared by grafting of polar monomers onto poly(tetrafluoroethylene) films. I. Some fractionations of liquid mixtures by pervaporation (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1061-1076 
    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 separation of various liquid mixtures including systems of chloroform-hydrocarbons or ethyl ether, water-alcohols and water-nucleophilic organic solvents have been investigated by the pervaporation technique. Membranes were obtained by grafting Lewis base onto poly(tetrafluoroethylene) (PTFE) films. The PTFE backbone has been chosen for its mechanical and chemical resistance. N-Vinylpyrrolidone and 4-vinylpyridine were selected because of their great affinity for the electrophilic compounds. In all cases, the compound which has the greatest affinity for the membrane pervaporates selectively through modified PTFE films. Selectivity and rates were studied. It is concluded that because selectivity is very important, total separation of different mixtures is possible at a good yield, with a faster rate when the temperature is increased or the thickness of the membrane is decreased.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160502
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  • 6
    Electronic Resource
    Electronic Resource
    Liquid transport through membranes prepared by grafting of polar monomers onto poly(tetrafluoroethylene) films. II. Some factors determining pervaporation rate and selectivity (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 351-364 
    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 effect of some factors including temperature, pressure, film thickness, and grafting ratio on the fractionation of binary liquid mixtures has been investigated by pervaporation through poly(tetrafluoroethylene) films grafted with N-vinylpyrrolidone or 4-vinylpyridine. The purpose was to estimate the best conditions in which the pervaporation process must be carried out. It was concluded that the pervaporation rate is increased at roughly constant selectivity when the temperature of the liquid charge is higher or when the downstream vapor pressure or the film thickness are decreased. A pressure higher than 1 atmosphere above the liquid does not increase the rate. When the grafting ratio is increased, the rate shows a maximum, and for particular conditions, the selectivity becomes much higher.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180204
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  • 7
    Electronic Resource
    Electronic Resource
    Detection of human somatic cell structural gene mutations by two-dimensional electrophoresis (1987)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 2 (1987), S. 13-19 
    Details
    ISSN: 0887-3585
    Keywords: two-dimensional electrophoresis ; ethylnitrosourea ; somatic mutations ; structural variants ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The feasibility of detecting human somatic structural gene mutations by two dimensional electrophoresis has been investigated. A lymphoblastoid cell line was grown as a mass culture in the presence of ethylnitrosourea, after which cells were regrown as single cell clones. A total of 257 polypeptide spots were analyzed in gels derived from 186 clones. Four structural mutations were detected by visual analysis of the gels. Computer analysis of gels corresponding to the mutant clones was also undertaken. At a spot size threshold of 200 spots to be matched using a computer algorithm, all four mutant polypeptides were detected. These results indicate the usefulness of the two-dimensional approach for mutagenesis studies at the protein level.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340020103
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  • 8
    Electronic Resource
    Electronic Resource
    Polymérisation radicalaire du pentadiène-1,3. II. Microstructure des résidus pentadiéniques dans les homo- et copolymères des cis et trans pentadiènes-1,3 avec l'acrylonitrile (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1093-1113 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The microstructure of diene units was investigated in radical homopolymers of the cis and trans isomers of 1,3-pentadiene and copolymers with acrylonitrile, synthetized in bulk and emulsion. Experiments were carried out by infrared spectroscopy, 100 MHz 1H-NMR, and 25 MHz 13C-NMR studies. No difference between the bulk and emulsion samples was noted. The microstructure of poly(1,3-pentadiene) is practically independent of the cis or trans configuration of the diene monomer and is as follows: 56-59% trans-1,4, 15-17% cis-1,4, 16-20% trans-1,2 7-10% cis-1,2 and 0% 3,4. On the other hand, up to about 30% of incorporated acrylonitrile (10% in the feed), the microstructure of the pentadiene fraction in the copolymers is not affected. This finding suggests that the penultimate unit has very little influence on the polymerization process involving the terminal pentadienly unit. Beyond 10% of acrylonitrile in the feed, the proportions of the structural units were linearly dependent upon the acrylonitrile content: trans-1,4 content increased whereas the amounts of cis-1,4 trans-1,2 and cis-1,2 decreased (except the cis-1,2 fraction, constant in the copolymers from the cis-diene). These results are discussed on the assumption that the microstructure of pentadiene residues is strongly associated with the acrylonitrile comonomer in the feed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1988.080260412
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  • 9
    Electronic Resource
    Electronic Resource
    Polymérisation radicalaire du pentadiène-1,3. I. Copolymérisation des cis et trans pentadiènes-1,3 avec l'acrylonitrile. Détermination des rapports de réactivité (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 883-900 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cis (CP) and trans (TP) isomers of 1,3-pentadiene (piperylene) were homo and copolymerized with acrylonitrile (A) in bulk and emulsion, at 50°C, using azobisisobutyronitrile and potassium persulfate as free radical initiators. The cis isomer reacts more rapidly than the trans monomer. The copolymer compositions were determined from nitrogen analysis, 100-MHz 1H-NMR and 25-MHz 13C-NMR spectra. The results thus obtained show that both the bulk and emulsion processes yield copolymers characterized by a very similar composition. Data plotted according to the Kelen-Tüdös method indicate that the terminal-unit model is applicable to the piperylene-acrylonitrile system. Reactivity ratios for bulk copolymerization were as follows: rA = 0.079, rTP = 0.114, and rA = 0.033, rCP = 0.188. These values are very small and hence suggest a strong alternating tendency for acrylonitrile and 1,3-pentadiene in both comonomer systems. This latter conclusion is corroborated by the comparison of the NMR spectra of the synthesized copolymers with that of a standard alternating sample. The reactivity (Q) and electronegativity (e) of the 1,3-pentadiene isomers calculated from the reactivity ratios by the Alfrey - Price equations were QTP = 0.56, eTP = -0.97 and QCP = 1.215, eCP = -1.055 for trans and cis dienes, respectively.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240507
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  • 10
    Electronic Resource
    Electronic Resource
    Caractéristiques géométriques de la séquence Hα—Cα—N—H de l'isoquinuclidone-3 examinée dans différents etats physiques influence sur la constante de couplage vicinal JHαH (1974)
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 523-536 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The X-ray structure analysis of a crystalline sample of 2-azabicyclo-[2,2,2]-octanone-3 or 3-isoquinuclidone shows that the molecules of this compound are associated in centrosymmetrical dimers stabilized by two N—H—O=C hydrogen bonds in which the N,H,O atoms are nearly collinear. As a consequence of this interaction, the H atom is shifted from its usual position and the Cα—N—H angle is increased to 125°.Using infrared spectroscopy (νN-H frequency range), it is possible to demonstrate that 3-isoquinuclidone is mainly in a dimeric form when dissolved in an inert solvent such as CCl4 and to observe the dimer-monomer equilibrium on dilution from saturation to a low concentration (0.005 mole/l.). On the contrary, dimers are broken off when operating in a polar medium (acetonitrile, deuterochloroform).In the same experimental conditions, measurements of the JHαH vicinal coupling constant, by nuclear magnetic resonance spectroscopy, afford a concentration-dependent result in the case of CCl4 solutions (increasing from 5.4 to 5.7 Hz when diluting from 0.5 to 0.005 mole/l.) and a constant one (5.8 Hz) in the case of CH3CN or CDCl3 solutions. Then the 0.4-Hz difference can be attributed to geometrical changes in the Hα—Cα—N—H system when dimers are broken off and the valence angle Cα—N—H consequently decreases from 125° to its standard value (about 115°). This experimental observation is consistent with the result of a theoretical analysis performed by the INDO method.Then it seems that the use of the formulas proposed by Karplus to account for the valence angle distorsions in ethane-like systems, in the case of the Hα—Cα—N—H sequence, could yield overstimated corrections.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1974.360130306
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