Showing papers by "Stockholm University published in 1973"
TL;DR: In the St. Elias Mountains in southern Yukon Territory and Alaska, C14-dated fluctuations of 14 glacier termini show two major intervals of Holocene glacier expansion, the older dating from 3300-2400 calendar yr BP and the younger corresponding to the Little Ice Age of the last several centuries.
863 citations
571 citations
TL;DR: A brief review of the concepts age distribution, transit time distribution, turnover time, average age and average transit time (residence time) and their relations is given in this article.
Abstract: A brief review is given of the concepts age distribution, transit time distribution, turn-over time, average age and average transit time (residence time) and their relations The characteristics of natural reservoirs are discussed in terms of these concepts, and a classification is proposed based on whether the average age is larger, equal to or smaller than the average transit time Some examples illustrate the differences between these various cases DOI: 101111/j2153-34901973tb01594x
518 citations
TL;DR: In this article, a discussion is given of atmospheric reactions in the H2O−CH4−O2−O3−NO ≥ 3−NO fixme x system.
Abstract: A discussion is given of atmospheric reactions in the H2O−CH4−O2−O3−NO
x
system. In the lower troposphere such reactions may lead to significant production of ozone. Their role in the odd hydrogen balance, especially of the troposphere and lower stratosphere, is discussed. CH3OH may be an intermediate in the oxidation cycle of methane, especially in the cold stratosphere. Its photodissociation into H2 and CH2O may consequently provide an important source for stratospheric H2. Catalytic photochemical chains of reactions involving NO
x
and HO
x
may also lead to tropospheric destruction of ozone. Due to lack of knowledge it is not possible at present to evaluate the importance of the before-mentioned reactions. With the aid of model calculations it is indicated that stratospheric ozone is most sensitive to changes in the adopted lower boundary values of N2O and that an increase in water vapour concentrations in the lower stratosphere will indeed cause some increase in ozone as predicted. Fluctuations in the flux of solar radiation near 190 nm may cause significant variations in stratospheric ozone concentrations.
485 citations
218 citations
167 citations
TL;DR: In this paper, a method for the selective degradation of polysaccharides containing uronic acid residues is described, which involves methylation of hydroxyl and carboxyl groups, base-catalysed elimination, and mild hydrolysis with acid.
149 citations
TL;DR: In this paper, detailed mapping of well-preserved moraine systems fronting 23 small glaciers in the Kebnekaise Mountains in Swedish Lapland reveals that the Holocene was punctuated by four prolonged intervals of...
Abstract: Detailed mapping of well-preserved moraine systems fronting 23 small glaciers in the Kebnekaise Mountains in Swedish Lapland reveals that the Holocene was punctuated by four prolonged intervals of ...
130 citations
TL;DR: The theory of van der Waals forces has now developed to a stage where it constitutes a powerful tool in theoretical investigations of many biological systems as mentioned in this paper, with the emphasis on the way they may be involved in various biological processes.
Abstract: The theory of van der Waals forces has now developed to a stage where it constitutes a powerful tool in theoretical investigations of many biological systems. In this review we shall consider both the theoretical and conceptual aspects of these forces with the emphasis on the way they may be involved in various biological processes.
109 citations
TL;DR: The results showed clear evidence for the existence of individual odor spaces, but in apparent contradiction to related studies in the literature individual differences were too large to establish a representative odor space for the whole group.
Abstract: Berglund, B., Berglund, U., Engen, T., & Ekman, G.1 Multidimensional analysis of twenty-one odors. Scand. J. Psychol., 1973, 14, 131–137.-The present paper reports an experiment on the application of multidimensional scaling to the sense of smell for the purpose of revealing basic psychophysical dimensions of odorants matched in perceived intensity and varying only in perceived quality. The results showed clear evidence for the existence of individual odor spaces, but in apparent contradiction to related studies in the literature individual differences were too large to establish a representative odor space for the whole group. For nearly all individual subjects one of the factors extracted seemed to represent a unique hedonic dimension apparently unrelated to the physical attributes of the odorants. It is suggested that such psychological factors may be as important a basis for the judgment of the similarity of odors as the physical attributes of the odorants. Both the interpretation of multidimensional analysis and the extent to which the sense of smell is analytic or synthetic depend on an understanding of this problem.
109 citations
TL;DR: The structure of the trisaccharide could be established as α-d-mannopyranoside-(1→3)-β-d.mannose moieties and 1 2-acetamido-2-deoxy- d-glucose residue, which is most probably a degradation product derived from the inner core of glycoprotein chains.
TL;DR: Water compartments, permeability, and the possible active translocation of various substances in rat liver microsomes were studied by using radioactive compounds and ultracentrifugation to disproved the hypothesis of an accumulation of charged substances inside of vesicles of being a major pathway.
Abstract: Water compartments, permeability, and the possible active translocation of various substances in rat liver microsomes were studied by using radioactive compounds and ultracentrifugation. The total water of the microsomal pellet, 3.4 µl/mg dry weight, is the sum of water in the extramicrosomal and intramicrosomal spaces, or 56 and 44%, respectively. Sucrose space accounts for 77% of the intramicrosomal water and the hydration water ∼ 14%, leaving almost no sucrose-impermeable space when using the ultracentrifugation approach. With increasing sucrose concentration, microsomes do not show an osmotic response. The intramicrosomal water decreases greatly in the presence of Cs+ and Mg++ in rough but not in smooth microsomes. Uncharged substances of molecular weight of up to at least 600 freely penetrate microsomal membranes, which already become impermeable to charged substances at a molecular weight of 90. These substances also induce an osmotic response. The vesicles can be made permeable to charged substances after water treatment and cooling, which, however, does not increase glucose-6-phosphatase and inosine diphosphatase (IDPase) activities, and these enzymes can still be activated by deoxycholate. IDPase, reduced nicotinamide adenine dinucleotide-cytochrome c reductase, and reduced nicotinamide adenine dinucleotide phosphate-dependent hydroxylation reactions, performed in vitro, also disproved the hypothesis of an accumulation of charged substances inside of vesicles of being a major pathway. The products of the enzymic reactions as well as the glucuronidated form of a hydroxylated product can be recovered on the cytoplasmic side of membranes, and little accumulation occurs in the intravesicular compartment.
TL;DR: Positive staining was inversely related to the number of lymphocytes with Fc or complement receptors or with surface immunoglobulin, thus suggesting that positive staining with FITC-conjugated hemagglutinin gave positive reactions with approximately 60% of the lymphocytes from normal donors.
Abstract: Neuraminidase treatment of human peripheral blood lymphocytes uncovers cell surface receptors that bind purified A hemagglutinin from the snail Helix pomatia. No hemagglutinin was bound to untreated lymphocytes. Binding studies with (125)I-labeled hemagglutinin suggested that the number of receptors on neuraminidase-treated lymphocytes was approximately 1.10(6)/cell. The apparent association constant for hemagglutinin binding to lymphocytes, as calculated from Scatchard's plots, was 5-7.10(8) liters/mol. Immunofluorescent staining with FITC-conjugated hemagglutinin gave positive reactions with approximately 60% of the lymphocytes from normal donors. Positive staining was inversely related to the number of lymphocytes with Fc or complement receptors or with surface immunoglobulin, thus suggesting that See PDF for Structure the lymphocytes with receptors for Helix pomatia A hemagglutinin are T cells. Cell fractionation on columns charged with hemagglutinin indicate that these receptors may be used for separating subpopulations of human peripheral lymphocytes.
TL;DR: In this paper, the MO-SCF-LCAO calculations have been carried out for benzene and the azabenzenes pyridine, pyridazine, pyrimidine, pyrazine, s-triazine and s-tetrazine.
TL;DR: In this article, all charged particles of transverse momentum p T between 1.5 and 4.4 GeV/c at center of mass angles 90° and 59.4° from p-p-collisions with √ s = 44 and 53 GeV has been measured.
TL;DR: The solvent deuterium effect on singlet oxygen lifetimes and azide quenching is used to demonstrate that the photodynamic inactivation of the enzymes alcohol dehydrogenase and trypsin involves Singlet oxygen.
Abstract: THE literature dealing with the photosensitized oxidation of proteins is extensive (Spikes and Livingston, 1969) and, although the changes occurring in the various protein molecules have been well described, the nature of the primary oxidizing entity is not known. At least two different reaction paths may be involved-one in which the protein reacts directly with the triplet state of the sensitizer, and an alternative pathway involving singlet-state excited oxygen (Kearns, 1969; Grossweiner, 1969; Kramer, 1972). Naturally, cases involving a mixed mechanism may also be conceived. In recent investigations we have determined the absolute lifetime of singlet oxygen (Merkel and Kearns, 1971, 1972) and developed diagnostic tests for singlet oxygen based on the large solvent deuterium effect on the lifetime of this excited state, as well as on the correlation between the lifetime of singlet oxygen and the intensity of the infrared absorption of the solvent (Merkel and Kearns, 1972; Merkel et al., 1972). Using these tools together with the phenomenon of quenching of singlet oxygen by azide (Hasty et al., 1972) and kinetic spectroscopy, conclusive evidence for the participation of singlet oxygen in the photosensitized oxidation of the free amino acids histidine, tryptophan and methionine was obtained (Nilsson et al., 1972). In the present Research Note we have used the solvent deuterium effect on singlet oxygen lifetimes and azide quenching to demonstrate that the photodynamic inactivation of the enzymes alcohol dehydrogenase and trypsin involves singlet oxygen.
TL;DR: Significant positive correlations were found between the secretion of both catecholamines and teachers' ratings indicating good social adjustment and emotional stability, as well as with measures of the pupils' subjective satisfaction with their school environment.
Abstract: Johansson, G. Frankenhaeuser, M. & Magnusson, D. Catecholamine output in school children as related to performance and adjustment. Scand. J. Psychol., 1973, 14, 20–28.-Excretion of two catecholamines, adrenaline and noradrenaline, was studied in a group of 240 children, sampled from a longitudinal study, during a “passive” period (viewing a film) and a subsequent “active” period (performing an arithmetic test). In the group of boys the mean adrenaline excretion increased significantly during the active as compared with the passive period. Among the children of both sexes, those who increased their adrenaline output during the arithmetic test as compared with the preceding passive period, performed better on the test in terms of speed and endurance, than did children who did not respond to mental work by adrenaline increase. Significant positive correlations were found between the secretion of both catecholamines and teachers' ratings indicating good social adjustment and emotional stability, as well as with measures of the pupils' subjective satisfaction with their school environment.
TL;DR: In this article, the eustatic changes closely follow climatic changes and the isostatic zero isobase is calculated for different areas of importance in the discussion of Holocene eustastic sea-level changes.
TL;DR: Two types of computationally efficient semi-implicit and leap-frog schemes for integrating the shallow-water equations are presented in this article, both for the pure initial value problem and for limited-area forecasts.
Abstract: Two types of computationally efficient semi-implicit and leap-frog schemes for integrating the shallow-water equations are presented. Their accuracy and stability are investigated, both for the pure initial value problem and for limited-area forecasts. The proper formulation of boundary conditions for the latter case is also discussed. Two sets of stable and sufficiently accurate boundary conditions are given. The practical usefulness of these conditions is also supported by computer experiments. DOI: 10.1111/j.2153-3490.1973.tb01601.x
TL;DR: A coupling factor purified from an acetone powder extract of Rhodospirillum rubrum chromatophores restores to decoupled chromatophile both photophosphorylation and Mg2+-dependent ATPase activities.
Abstract: 1
A coupling factor has been purified from an acetone powder extract of Rhodospirillum rubrum chromatophores This restores to decoupled chromatophores (extracted with respect to coupling factor) both photophosphorylation and Mg2+-dependent ATPase activities The coupling factor had been partially purified by gel filtration through a Sepharose 6B column, and further purified by ultra-filtration and sucrose-density-gradient centrifugation At each stage of purification, the coupling factor activity was coincident with a Ca2+-dependent ATPase activity, increasing in total activity during the purification Mg2+, Mn2+, Co2+ or Zn2+ could not substitute for Ca2+ in activation of this soluble ATPase, but these four metals strongly inhibited the activity of the Ca2+-dependent ATPase
2
By incubation with decoupled chromatophores, the soluble Ca2+-dependent ATPase was rebound to the membrane in the presence of either Mg2+ or Ca2+ This binding resulted in a partial masking of the Ca2+-dependent ATPase activity of the soluble enzyme
3
The purified ATPase has a Km value of 12 mM for ATP The Ki values for inhibition of the soluble Ca2+-dependent ATPase by Mg2+ (170 μM), and by ADP (42 μM) are in close agreement with the corresponding Km values for Mg2+-dependent ATPase and photophosphorylation, respectively, as measured with chromatophores
4
The membrane-bound Mg2+- or Ca2+-dependent ATPase activities were inhibited by oligomycin Azide and parahydroxymercuribenzoate inhibited both the soluble and the membrane-bound ATPase activities Treatment with phospholipase A inhibited both the membrane-bound ATPase, but had no effect on the soluble Ca2+-dependent ATPase
5
The sedimentation constant at 1 mg protein/ml of the extensively purified coupling factor is s20, w= 131 × 10−13 s, and the approximate molecular weight 350000
TL;DR: In this article, the effect of an external field on the oxonium ion, H3O+, has been studied with the MO-LCAO method in order to determine its equilibrium geometry.
Abstract: The oxonium ion, H3O+, has been studied with the MO-LCAO method in order to determine its equilibrium geometry. The main purpose has been to study effects of the external electrostatic forces exerted on the ion situated in crystals whose structures are experimentally known. Calculations have also been performed on the free ion, where the energy minimum is found for a non-planar conformation with H-O-H angles of 116.6° and O-H distances of 0.96 A. The effect of an external field is essentially to lengthen the O-H distances and decrease the H-O-H angles in order to form approximately linear hydrogen bonds.
TL;DR: Results of binding experiments with a series of derivatives of dodecane suggest that type I binding to cytochrome P-450K requires, besides a proper chain length, the presence of a carbonyl group together with an electron pair on a neighboring atom at the end of the carbon chain.
TL;DR: In this article, a phenomenological expansion of nuclear rotational energies terms of the angular velocity is discussed and applied to the doubly even nucleaides in the mass between Ce and Pt.
TL;DR: A kinetic scheme is presented, which involves loops corresponding to one ping pong and one sequential mechanism that can explain all experimental findings obtained so far in glutathione reductase.
01 Jan 1973
TL;DR: The chemistry of the stratosphere has become a very important and controversial topic, since it was proposed that large scale SST operation could cause a reduction in atmospheric O3 due to the catalytic action of nitrogen oxides emitted from the exhaust as discussed by the authors.
Abstract: The chemistry (and meteorology) of the stratosphere has become a very important and controversial topic, since it was proposed that large scale SST operation could cause a reduction in atmospheric O3 due to the catalytic action of nitrogen oxides emitted from the exhaust (Crutzen, 1971; Johnston, 1971.) There are strong indications that oxides of nitrogen play the dominant role in controlling the natural atmospheric O3 content (Crutzen, 1970), but too little is known about the details of the chemistry of nitrogen oxides in the stratosphere, a subject which is treated by Nicolet (1971). Important new ideas have emerged in recent years about the main chemical processes in the stratosphere. The main purpose of this paper is to outline some of these ideas and to indicate the main problems. Some possible consequences for the gas phase chemistry of the troposphere have been indicated on the basis of recent models by Levy (1971, 1972) and McConnell et al. (1971).
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TL;DR: When subjects whose adrenalineoutput decreased rapidly were compared with those whose adrenaline output decreased slowly, it was found that ‘rapid decreasers’ had higher baseline levels of adrenaline, performed better on the choice-reaction task, and had lower scores in neuroticism.
TL;DR: In this article, data on the inclusive production spectra of K S 0 and Λ from proton-proton collisions at 19 GeV were presented and discussed in connection with the earlier studied inclusive π − production spectrum.