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  • Cell & Developmental Biology  (6)
  • Atomic, Molecular and Optical Physics  (4)
  • Computational Chemistry and Molecular Modeling  (4)
  • Field-flow fractionation  (3)
Material
Years
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 34 (1992), S. 325-330 
    ISSN: 1612-1112
    Keywords: Field-flow fractionation ; Secondary chemical equilibria ; Colloidal systems ; Retention theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The application range of field-flow fractionation (FFF) can be extended to low molecular weight solutes, as demonstrated a few years ago by Berthod et al., by taking profit of secondary chemical equilibria (SCE) occurring between the bulk carrier and a retained carrier component. The theory of solute retention in this SCE-FFF method is developed for any value of the solute distribution coefficient and of the retention ratio of the retained carrier component, provided that the Brownian mode of retention applies for this component and that the flow velocity profile is parabolic. This removes some of the limitations of the model previously developed by Berthod and Armstrong and sheds light on the potentialities of the SCE-FFF method for physico-chemical studies about secondary chemical equilibria in colloidal systems. Remaining assumptions in the model are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 1643-1652 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron density and the molecular electrostatic potential of the β-carbolines are studied using ab initio STO-3G wave functions. The analysis was done from the point of view of a previous model built with monoamine oxidase substrates and irreversible inhibitors. The results confirm the usefulness of the model and make it possible to propose new precision to the molecular electrostatic potential patterns needed to have monoamine oxidase inhibitory activity.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 1627-1641 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Similarities and differences between mitochondrial monoamine oxidase (MAO) substrates and inhibitors (both A and B types) are considered, studying quantitatively two molecular properties: electron density and molecular electrostatic potential (MEP). The following molecules are considered: substrates: PHEA, BZA, tele-N-methyl-histamine, phenylethanolamine, phenylpropylamine, tryptamine, dopamine, phenoxylethylamine, noradrenaline, serotonin, and p-nitro-phenylethanolamine; inhibitors: Deprenil, Clorgyline, and Lilly 51641 (only the moiety involved in the A-B differentiation is considered). The wave functions needed to calculate the analyzed properties are of ab initio quality, and have been calculated in analogous conformations, all near the energetic minima. Electron densities distributions are qualitatively compared by means of a correlation coefficient defined over the whole space. Otherwise, patterns of the possible zones of electrostatic interactions are described by means of the distances and angles between minima, in order to differentiate MAO-A and MAO-B substrates. The results reproduce efficiently the experimental classification and enable us to predict the type of enzymatic action of molecules not yet experimentally classified.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 15 (1982), S. 426-432 
    ISSN: 1612-1112
    Keywords: Polymer analysis ; Molecular weight distribution ; Steric exclusion chromatography ; Field-flow fractionation ; Light scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The classical method for the determination of the molecular weight distribution (MWD) curve of a polymer requires fractionation according to the molecular weight and prior calibration of the separator. It is shown that the use of a dual detection system which includes a molecular mass sensitive detector eliminates the need for prior calibration. The principles of operation of a low-angle light scattering photometer, working as such a detector, are presented, as well as the basic equations for determination of the MWD curve from the elution curve and of the average molecular weights. Then the performances of the light scattering photometer are discussed with special emphasis on the various sources of errors and unaccuracies in these determinations.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1612-1112
    Keywords: Field-flow fractionation ; Three-dimensional flow velocity profile ; Rectangular cross-section channel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The shape of the velocity profile established in a carrier liquid flowing in a duct of rectangular cross-section under conditions of isoviscous flow is well known and can be calculated by using an approximate or the exact solution of Navier-Stokes equation. The series evaluated when applying the exact solution were found to converge very rapidly. Consequently, computing can be substantially shortened without loss of accuracy by summing only the first three terms of the series. A fair agreement between the approximate solution of Takahashi and Gill and the exact solution was obtained for all practically applicable aspect ratios of the separation channels used in field-flow fractionation. This conclusion is of interest when calculating various separation parameters in three-dimensional channels for field-flow fractionation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 46 (1993), S. 515-518 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Squeezed states are normally studied in configuration space or using the Glauber formalism for the coherent states. Here we show that the use of the Fock-Bargmann space can lead to more general solutions, especially in the case of squeezed states associated with the square of field amplitude. The relations that we obtain are completely general and several well-known, approximate results can be obtained as the limit cases of our approach.© 1993 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 30 (1991), S. 100-104 
    ISSN: 1040-452X
    Keywords: Embryo ; Incision ; Zona pellucida ; Trophoblast ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Experiment I was designed to determine if cell-free synchronous uterine flushings contain an embryotoxic substance that is normally screened by the intact zona pellucida. Sixty 4-cell embryos were allocated to three treatment groups: (1) control embryos (n = 20) were cultured in Modified Kreb's Ringer Bicarbonate medium + 10% bovine calf serum (mKRB-BCS), (2) UF embryos (n = 20) were cultured in 80% mKRB-BCS + 20% sterile dialyzed uterine flushings (UF), (3) MicroUF embryos (n = 20) received a microsurgical incision in the zona pellucida and were cultured in 80% mKRB-BCS + 20% UF. Following 72 h in culture at 37°C under a 90% N2, 5% CO2, and 5% O2 atmosphere, the number of nuclei/embryo and the incidence of protrusion of the trophoblast through the zona pellucida (PTZ) were recorded. Addition of UF had no effect on embryo development. A greater (P 〉 .005) proportion of MicroUF embryos exhibited PTZ as compared to UF and control embryos. Experiment II was devised to further characterize the occurrence of PTZ in Micro porcine embryos. Thirty-three 4- to 10-cell embryos and 14 morulae were distributed across two treatments: (1) control embryos (n = 16 and 6, respectively) were cultured as described in Experiment I; and (2) micro embryos were treated similarly to MicroUF embryos in Experiment I but were cultured in mKRB-BCS only. At the onset of PTZ, embryos were immediately fixed and examined. The proportion of embryos exhibiting PTZ was greater (P 〈 .007) for Micro versus control embryos. Both the mean time to PTZ and the number of nuclei present were greater for blastocysts cultured from control as opposed to Micro morulae (P 〈 .0001 and P 〈 .0002, respectively). These results indicate that (a) cell-free synchronous uterine flushings are not detrimental to embryos with incised zonae and (b) microsurgery increases the incidence of and reduces the time to protrusion of the embryo through the zona pellucida in cultured embryos.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 113 (1982), S. 1-6 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 127-134 
    ISSN: 0148-7280
    Keywords: lipid peroxidation ; human sperm motility ; morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The formation of malondialdehyde (MDA), a product of lipid peroxidation (LPO), was measured in human spermatozoa from 27 subjects with normal sperm characteristics. Peroxidation of lipids in washed spermatozoa was induced by catalytic amounts of ferrous ions and ascorbate and malondiaidehyde dctermint-d by thiobarbituric method. MDA formation varied considerably from one sample to another. The studied population showed a strong correlation between lipid peroxidation potential (amount of MDA formed by 108 spermatozoa after 1 hour of incubation) and 1) initial motility r = -0.623, P = 0.001; and 2) morphologic abnormalities of the midpiece r = 0.405, P = 0.05. These results suggest that poor motility is linked with membrane fragility and that spermatozoa with midpiece abnormalities probably have membrane and/or cytoplasmic antiperoxidant system defects. Because LPO potential is related to the two most important characteristics of fertility, it seems possible that it has the potential to become a good biochemical index of semen quality.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 23 (1989), S. 229-232 
    ISSN: 0148-7280
    Keywords: mouse model ; IVF ; environment ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A study of mouse gamete processing for in vitro fertilization (IVF) under various conditions showed that it is necessary to control the atmosphere if the temperature is raised from 22°C to 37°C. The data suggest that maximum IVF success is attained by processing the gametes at 37°C, under an atmosphere of 5% O2 and 5% CO2, and overlaying the medium with silicone oil.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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