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Showing papers by "National University of La Plata published in 1976"


Journal ArticleDOI
TL;DR: Studies were carried out to relate the changes of the fatty acid and lipid composition of rat microsomes with the modification of the activity of the linoleic acid desaturation evoked by an essential fatty acid deficient diet.

60 citations


Journal ArticleDOI
TL;DR: The effect of epinephrine was postulated to be mediated through an enhancement of the intracellular cyclic AMP levels that lead to an increase of a glucose metabolite that would inhibit delta6-desaturation activity.

41 citations


Journal ArticleDOI
TL;DR: The furanoid isomer of diadinoxanthin, absent during logarithmic growth, appears increasingly during the nutrient-deficient period, and changes in the amounts of chlorophyll a, chlorophyLL c and fucoxanthin are quite similar.
Abstract: Changes in the amounts of chlorophyll a, chlorophyll c, fucoxanthin, diadinoxanthin and β-carotene were determined during Phaeodactylum tricornutum growth. The transition of the culture from the logarithmic to the stationary phase is accompanied by an increase in the carotenoids: chlorophyll a ratio, associated with variations in the percentage of individual carotenoids. While fucoxanthin content decreases with the age of the culture, diadinoxanthin content increases and β-carotene remains almost constant. The furanoid isomer of diadinoxanthin, absent during logarithmic growth, appears increasingly during the nutrient-deficient period. Changes in the amounts of chlorophyll a, chlorophyll c and fucoxanthin are quite similar.

38 citations


Journal ArticleDOI
TL;DR: HTC cells were sensitive to insulin which enhanced the de-saturating route increasing eicosapentaenoic acid synthesis and depressed the elongating route decreasing eicOSatrienoic acid, and dibutyryl cyclic AMP decreased eicosa-11,14,17-tetraenoic Acid synthesis and increased eicosi-5,8,11, 14, 17-pentaenoic acids.
Abstract: Incubation of HTC cells (7288 C) with 114C-α-linolenic acid in Swim's 77 medium during 24 hours converted the fatty acid to octadeca-6,9,12,15-tetraenoic acid, eicosa-11,14,17-trienoic acid, eicosa-8,11,14,17-tetraenoic acid, eicosa-5,11,14,17-tetraenoic acid, eicosa-5,8,11,14,17-pentaenoic acid and unsaturated acids of 22 carbons The existence of two pathways was recognized: one initiated by a Δ6-desaturation and the other by an elongation ofα-linolenic acid Incubation of the cells with insulin and dibutyryl cyclic AMP modified both pathways in different ways HTC cells were sensitive to insulin which enhanced the de-saturating route increasing eicosapentaenoic acid synthesis and depressed the elongating route decreasing eicosatrienoic acid In an opposite way, dibutyryl cyclic AMP decreased eicosapentaenoic acid synthesis and increased eicosatrienoic acid

33 citations


Journal ArticleDOI
TL;DR: The following hydrated nitroprussides are described in this paper : Mn[Fe(CN) 5 NO]·2H 2 O, 2H 2 OD, Fe[Fe 5 NO], 4H 2 NO, Co[Fe 6 NO], Ni[Fe 7 NO], 6H 2 OM, Ni[Ni[Fe 8 NO], 3H 2 HO, Ni [Ni] 2 O], 4HO, Cu[Fe 9 NO], 2H 3 O, Zn[Fe 10 NO], Cd[Cd[Fe 11 NO], Z

29 citations


Journal ArticleDOI
01 Dec 1976-Lipids
TL;DR: The hypothesis that the oxidative desaturation of linoleic acid to γ-linolenic acid is the main controllable step in the biosynthesis of polyunsaturated fatty acids of the linoleoic acid family in the microsomes is supported.
Abstract: The effect of glucagon, dibutyryl cyclic adenosine 3′,5′-monophosphate, and epinephrine on the biosynthesis of polyunsaturated fatty acids of the linoleic acid family was studied. The incubations were performed with rat liver microsomes and labeled linoleic acid under desaturating and elongating conditions. Under desaturating conditions, linoleic acid was converted to γ-linolenic acid, whereas under elongating conditions it was converted to 20∶2ω6. Glucagon, dibutyryl cyclic AMP, and epinephrine decreased the oxidative desaturation of linoleic acid to γ-linolenic acid while the elongating reaction was not modified in the experimental conditions tested. Consequently, the results support the hypothesis that the oxidative desaturation of linoleic acid to γ-linolenic acid is the main controllable step in the biosynthesis of polyunsaturated fatty acids of the linoleic acid family in the microsomes.

27 citations


Journal ArticleDOI
TL;DR: In this paper, the infrared spectra of the isostructural MVO3 compounds (M=K, Rb, Cs, Tl, NH4), consisting in an array of infinite tetrahedral chains, are reported and discussed with the aid of a simplified factor group analysis.
Abstract: The infrared spectra of the isostructuralMVO3 compounds (M=K, Rb, Cs, Tl, NH4), consisting in an array of infinite tetrahedral chains, are reported and discussed with the aid of a simplified factor group analysis. In the case of NH4VO3 also the laser-Raman spectrum was recorded and analyzed. Force constants, mean amplitudes of vibration and other bond properties for the terminal VO2 groups, as well as for the VOV chain units are estimated.

18 citations


Journal ArticleDOI
TL;DR: The effect of three different carbon sources on the biosynthesis of polyunsaturated fatty acids of theα-linolenic acid series was investigated in hepatoma tissue culture (HTC) cells and ‘Fasting’ decreased both biosynthetic routes whereas glucose reactivated only the elongating pathway.
Abstract: The effect of three different carbon sources on the biosynthesis of polyunsaturated fatty acids of theα-linolenic acid series was investigated in hepatoma tissue culture (HTC) cells. Alpha linolenic acid was converted to higher homologs by a desaturating route that synthetized mainly 18:4 (Δ6, 9, 12, 15), 20:4 (Δ8, 11, 14, 17) and 20:5 (Δ5, 8, 11, 14, 17) and an elongating route that produced 20:3 (Δ11, 14, 17) and 20:4 (Δ5, 11, 14, 17) acids. ‘Fasting’ decreased both biosynthetic routes whereas glucose reactivated only the elongating pathway. Lactalbumin hydrolysate enhanced significantly only the desaturating route whereas glycerol was inactive. Glucose and aminoacids increased similarly the incorporation of labeledα linolenic acid in the cells. The results are independent of hormonal effects.

15 citations


Journal ArticleDOI
TL;DR: In this article, the infrared and Raman spectra of Ca3(VO4)2 are reported and discussed with the aid of the Site-Symmetrie (SS) rules.
Abstract: Inhaltsubersicht. Die IR- und Raman-Spektren von Ca3(VO4)2 wurden aufgenommen und an Hand der “Site-Symmetrie”-Regeln interpretiert. Auch das IR-Spektrum des isostrukturellen Ca3(AsO4)2 wurde zu Vergleichszwecken untersucht. The Vibrational Spectra of Ca3(VO4)2 and Ca3(AsO4)2 Abstract. The infrared and Raman spectra of Ca3(VO4)2 are reported and discussed with the aid of the “site symmetry” rules. For comparative purposes, the i.r. spectrum of the isostructural Ca3(AsO4)2 has been also analyzed.

15 citations




Journal ArticleDOI
TL;DR: In this paper, a calculation of the excess internal energy and the osmotic coefficient for a mixture of charged hard spheres of diameters equal to the ionic radii of NaCl, is done in the mean spherical approximation.

Journal ArticleDOI
TL;DR: In this article, the infrared and laser-Raman spectra of synthetic carnotite, K2[(UO2)2V2O8], are reported and discussed.
Abstract: The infrared and laser-Raman spectra of synthetic carnotite, K2[(UO2)2V2O8], are reported and discussed. Force constants for the terminal V-O bonds as well as for the UO22+ ions are evaluated. From the spectroscopic data, a U-O bond length of 1.81 A is estimated for the uranyl ion in this compound.


Journal ArticleDOI
01 Dec 1976
TL;DR: In this article, the structure of the odd-mass technetium isotopes is analyzed with the Alaga model which involves the coupling of a three-particle valence-shell cluster to the quadrupole vibrational field.
Abstract: The structure of the odd-mass technetium isotopes is analyzed with the Alaga model which involves the coupling of a three-particle valence-shell cluster to the quadrupole vibrational field. The calculated energy-level sequence and decay properties are consistent with the general trend of the available experimental information although no attempt of the best fit to individual properties was pursued.

Journal ArticleDOI
TL;DR: In this paper, the chain length distribution of polymer analogous nitrates of two native bacterial celluloses is investigated and the polymerization times of the latter differend in the numbers of generation of the bacteria produced during the fermentation of acetobacter xylinium.
Abstract: The chain length distribution of polymer analogous nitrates of two native bacterial celluloses is investigated. The polymerization times of the latter differend in the numbers of generation of the bacteria produced during the fermentation of acetobacter xylinium. The resulting distribution curves show that polydispersity and number of maxima increase with increasing number of generation. This result supports the hypothesis deduced from former kinetic investigations that each generation of bacteria initiates a certain number of molecules and that chain growth takes place without termination step. Es wurde die Kettenlangenverteilung der polymeranalogen Nitrate zweier nativer Bakteriencellulosen untersucht, deren Polymerisationszeiten sich in der Anzahl der wahrend der Fermentation von Acetobacter Xylinum entstandenen Bakteriengenerationen unterschied. Es zeigte sich, das die Breite der Verteilung sowie die Anzhal der Maxima mit steigender Anzahl der Generationen zunimmt. Dieser Befund unterstutzt die auf Grund vorangehender kinetischer Untersuchungen abgeleitete Hypothese, das jede Bakteriengeneration eine bestimmte Anzahl Molekule startet und das Kettenwachstum dann ohne Abbruchschritt verlauft.

Journal ArticleDOI
TL;DR: Mean amplitudes of vibration of a series of hexaoxometalates have been estimated using an approximation method and recently reported spectroscopic data arising from the study of the respective lithium salts as mentioned in this paper.
Abstract: Mean amplitudes of vibration of a series of hexaoxometalates have been estimated using an approximation method and recently reported spectroscopic data arising from the study of the respective lithium salts.

Journal ArticleDOI
TL;DR: In this paper, the anodic dissolution of nickel in HCl-DMSO solutions containing different supporting electrolytes has been studied between 20-40°C, where the electrodissolution and electrodeposition are predominantly activated electrode processes.

Journal ArticleDOI
TL;DR: The twelve tri-N-sulphonylhexhexahydro-1,3,5-triazine (R = alkyl or aryl) exhibit a common fragmentation pattern; most of the fragments are directly or indirectly generated from the [M RSO2]+ ion.
Abstract: The twelve tri-N-sulphonylhexahydro-1,3,5-triazines (R = alkyl or aryl) exhibit a common fragmentation pattern; most of the fragments are directly or indirectly generated from the [M RSO2]+ ion. Tri-N-Benzylsulphonylhexahydro-1,3,5-triazine (R = PhCH2) departs from the others mainly because the key ion [M RSO2]+ suffers a skeletal rearrangement with loss of SO2. The rationalizations presented are supported by metastable evidence, accurate mass measurements and deuterium labelling.

Journal ArticleDOI
TL;DR: In this article, the Raman spectra of liquid and solid bromyl fluoride, BrO2F, have been obtained and interpreted and in an attempt to obtain a deeper insight in the bond properties of this molecule, it seems interesting to determine some of its vibrational properties.
Abstract: Recently the Raman spectra of liquid and solid bromyl fluoride, BrO2F, have been obtained and interpreted1; therefore, and in an attempt to obtain a deeper insight in the bond properties of this molecule, it seems interesting to determine some of its vibrational properties.

Journal ArticleDOI
TL;DR: In this paper, the mean amplitudes of vibration for SF5Cl and SeF5Cl were calculated from spectroscopic data in the temperature range between 0 and 1000 K. The results were briefly discussed in comparison with those of related species.
Abstract: Mean amplitudes of vibration for SF5Cl and SeF5Cl have been calculated from spectroscopic data in the temperature range between 0 and 1000 K. The results are briefly discussed in comparison with those of related species. Some aspects concerning the bond properties of the two molecules are also analyzed.

Journal ArticleDOI
TL;DR: In this article, the infrared and laser-Raman spectra of crystalline Ba5(ReO6)2 have been used to calculate force constants and mean amplitudes of vibration for the ReO65− ion.
Abstract: The infrared and laser-Raman spectra of crystalline Ba5(ReO6)2 are reported and discussed. From the obtained spectroscopic data a calculation of force constants and mean amplitudes of vibration for the ReO65− ion has been carried out.


Journal ArticleDOI
TL;DR: In this paper, the kinetics of the hydrogen electrode reactions on Pt in the NaHSO4 + KHSO 4 melt at ca. 185°C were studied under potentiodynamic conditions.

Journal ArticleDOI
TL;DR: The circadian variation of the insulin-induced hypoglycemia depends on the time recovery from the glucose fall rather than on lower circulating glucose levels attained following hormone injection, which underline the importance of considering circadian variations when planning either experimental designs or insulin therapy.
Abstract: The hypoglycemic effect of i.v. insulin injected at 4 different times of day was studied in normal volunteers. It was found that the glucose fall induced by this treatment was quantitatively different, with the maximum effect observed at 1800 and 2400. The circadian variation of the insulin-induced hypoglycemia depends on the time recovery from the glucose fall rather than on lower circulating glucose levels attained following hormone injection. These results underline the importance of considering circadian variations when planning either experimental designs or insulin therapy.

Journal ArticleDOI
TL;DR: In this paper, an object with a mean radial velocity of −212.3 km s−1 has been observed in the 21 cm neutral hydrogen line and the total mass is estimated to be 190R2 (kpc) solar masses.
Abstract: An object located approximately atl=8°,b=−4° with a mean radial velocity of −212.3 km s−1 has been observed in the 21 cm neutral hydrogen line. The mean weighted velocity dispersion is 11.2 km s−1 and the total mass is estimated to be 190R2 (kpc) solar masses. We discuss possible interpretations of the origin and nature of this object. The most likely interpretation is that we observe an expanding object which has been ejected from the galactic nucleus.

Journal ArticleDOI
TL;DR: In this article, the impedances and leakage conductance of a cylindrical multiconductor system are calculated in the high-frequency limit, where the akin effect is dominant. And a rigorous proof of the so-called Wheeler's incremental inductance rule is given, baaed on some results of the domain variational theory for harmonic functions.
Abstract: The impedances and leakage conductance of a cylindrical multiconductor system are calculated in the high-frequency limit, where the akin effect is dominant. A rigorous proof of the so-called Wheeler's incremental inductance rule is given, baaed on some results of the ‘domain variational theory’ for harmonic functions.


Journal ArticleDOI
TL;DR: The mean amplitudes of vibration of the ClO2F2− anion have been calculated using known spectroscopic data in this article, and the results are briefly discussed and comparisons are made with other species containing Cl−O and Cl−F bonds.
Abstract: The mean amplitudes of vibration of the ClO2F2− anion have been calculated using known spectroscopic data. The results are briefly discussed and comparisons are made with other species containing Cl−O and Cl−F bonds.

Journal ArticleDOI
TL;DR: In this article, the i.r. spectra of HgCl(SCF3) were studied in a low temperature matrix, in CS2 solution and in the crystalline state (both as a powder mull and as monocrystals).