Showing papers by "University of Würzburg published in 1972"

Replacement of t-cell function by a t-cell product.

Abstract: WE have recently shown that the immune response to sheep red blood cells (SRBC) in vitro is T-cell dependent, that is, it can be abrogated by pretreatment of the spleen cells with anti-θ serum and complement1. We further reported that reconstitution of the system can be achieved by, among other things, the addition of allogeneic thymocytes2, while syngeneic thymocytes failed to function as helper cells. Positive allogeneic effects were only obtained if the added thymocytes could recognize the remaining B-cells as foreign. One of the explanations evoked for this allogeneic effect was the participation of a potentiating factor2,3. It seemed possible that on the heavy antigenic stimulation provided by the histocompatibility antigens carried by the B-cells, added T-cells produce a soluble factor which stimulates the immune response of B-cells to unrelated antigens. We now want to report the existence of two distinct factors, one of which can completely replace T-cells.

Stomatal responses to changes in humidity in plants growing in the desert.

Abstract: The stomata of plants growing in the Negev Desert, namely the stomata of the mesomorphic leaves of Prunus armeniaca, the xeromorphic stems of Hammada scoparia, and the succulent leaves of Zygophyllum dumosum, respond to changes in air humidity. Under dry air conditions diffusion resistance increases. Under moist air conditions diffusion resistance decreases. When the stomata close at low air humidity the water content of the apricot leaves increases. The stomata open at high air humidity in spite of a decrease in leaf water content. This excludes a reaction via the water potential in the leaf tissue and proves that the stomatal aperture has a direct response to the evaporative conditions in the atmosphere. In all species the response to air humidity is maintained over a period of many hours also when the soil is considerably dry. The response is higher in plants with poor water supply then in well watered plants. Thus for field conditions and for morphologically different types of photosynthesizing organs the results confirm former experiments carried out with isolated epidermal strips.

Occurrence of Epstein-Barr virus genomes in human lymphoblastoid cell lines.

Abstract: DURING the past two years, work in this and other laboratories has demonstrated viral genomes characteristic of Epstein–Barr (EB) virus in cell lines and biopsy cells derived from Burkitt lymphomas1–4, and anaplastic carcinomas of the nasopharynx5. Our technique consists of hybridizing DNA from the cells concerned with the complementary RNA (cRNA) obtained by the transcription of EB virus DNA in vitro with E. coli RNA polymerase. We have now applied the technique to various lymphoblastoid cell lines which lack virus particle and structural viral antigens and found that they all seem to carry EB virus genomes. DNA from human umbilical cord leucocytes, however, seems to be free of such genomes.

Trimethylphosphinkomplexe von Methylnickel-Verbindungen

Abstract: Es wird uber Darstellung und Eigenschaften komplexer Methylnickel-Verbindungen L2 NiR2 und L2NiRX (L (CH3)3P, R CH3, X Cl, Br, J) berichtet. Auskunft uber ihre Struktur in Losung wird aus den 1H-NMR-Spektren bei tiefen Temperaturen und aus den Infrarotspektren erhalten. Durch Addition weiterer Phosphinliganden entstehen die Komplexe L3NiR2 und L4NiRX. Methylnickel Compounds Containing Trimethylphosphine Ligands Methods of preparation and properties of methylnickel complexes are reported. The structure of L2NiR2 and L2NiRX (L (CH3)3P, R CH3, X Cl, Br, J) in solution can be determined by means of their low temperature 1H n.m.r. and infrared spectra. Addition of phosphine ligands yields new complexes L3NiR2 and L4NiRX.

Metabolism of trichloroethylene in man. I. The significance of trichloroethanol in long-term exposure conditions.

Abstract: Groups of 5 to 6 volunteers each participated in three experimental series involving inhalation of analytically controlled trichloroethylene concentrations for 6 h daily on 5 successive week days: (a) 50 ppm constant, (b) 250 ppm for 12min/h (high peak concentrations, average 50 ppm); (c) 100 ppm constant. The trichloroethanol (TCE) levels in the blood were determined 3 times daily, the TCE and trichloroacetic acid (TCA) levels in the urine twice daily by means of gas Chromatographic (TCE) and colorimetric (TCA) techniques. It was seen that TCE accumulates in the blood from day to day reaching maximum values of (a) 2.0 μg/ml, (b) 2.5 μg/ml, or (c) 5.0 μg/ml; the half life of TCE in the blood was 12 h in each case. After a single dose of 15 mg/kg chloral hydrate (normal hypnotic dose) TCE reached levels of approx. 7 μg/ml within 1 h; the pattern of elimination was identical to that obtained after Tri inhalation. The maximum TCE value after 100 ppm Tri coincides with that obtained 2 to 2 1/2 h after ingestion of chloral hydrate. There are some data in the literature indicating that such TCE levels reduce the performance ability in vigilance tests. The formation and accumulation of TCE probably is responsible for the “psycho-organic syndrome” encountered during occupational exposure to Tri. On inhalation of Tri for several days the urinary excretion of TCE and TCA does not follow certain rules which may be derived from single experiments (for instance, 6 h-inhalations). It would appear, therefore, that the procedures described in the literature for assessment of Tri exposure on the basis of TCE and/or TCA excretion are subject to revision.

Trichloroethylene exposure and trichloroethylene metabolites in urine and blood

Abstract: After trichloroethylene (Tri) inhalation the metabolite trichloroethanol (TCE) is excreted rapidly in the urine, while trichloroacetic acid (TCA) accumulates in the organism due to a high plasma protein binding rate. After exposure of 5 volunteers to 50 ppm Tri for 6 h, 50 μg/ml TCA is found in the plasma at the end of the 5th exposure day, the amount of TCE present in the blood amounting to not more than 2.3 μg/ml. Instead of the previously used control of TCE + TCA in the urine, it is suggested to determine the metabolites in the blood by means of a gas Chromatographic micro technique which provides a reliable criterion of the preceding Tri exposure.

Standardization of enzyme assays.

Abstract: Standardization of methods requires an enormous amount of work, organization, and the good will and cooperation of many people. The work on standardization has to be done in such a manner that all laboratories are willing to follow the decisions of these standardizing commissions. Therefore, the methods must be selected carefully in order to make them acceptable to most laboratories. Also, one should only choose those methods that have already been proven and that fulfill the strict requirements necessary for modern analytical methods. This is the first step in the standardization of methods. A second part of the work is the effort of international commissions to create definite terms and units in clinical chemistry-for enzyme nomenclature, enzyme activity, weight, volume, and concentration (units)-and to fix an international standard temperature. The third part will be a great deal of experimental work for the determination of optimal measurement conditions for the selected methods. Having obtained these results, we get the standardized conditions for measurement, but, as Figure 1 shows, it is not enough for the completely standardized enzymatic assay method. Other factors are to be considered: the stability of the compound to be assayed in the sample as well as the sampling itself, and on the other hand, the availability of stable and defined reference standards. Only with all these factors considered do we get a standardized enzymatic assay method (1).

Cellular autophagy and cell atrophy in the rat liver during long-term starvation. A quantitative morphological study with regard to diurnal variations.

Abstract: A quantitative approach was made to describe cellular autophagy in normal rat liver cells and during starvation from 1 to 10 days The following methods were combined: 1) morphometric evaluation of light and electron microscopical photographs; 2) counting of autophagic vacuoles directly on the electron microscope screen In controls (24 animals) the frequency of autophagic vacuoles containing all the main cytoplasmic constituents, endoplasmic reticulum + ground substance, mitochondria, microbodies, and glycogen shows marked diurnal variations During long term starvation (38 animals) this rhythm is no longer visible when comparing animals killed at day and at night

Mono- and divalent electrolyte patterns, pCO 2 and pH in relation to flow rate in normal human parotid saliva.

Abstract: In parotid saliva of normal subjects the pH, pCO2 and concentrations of sodium, potassium, calcium, magnesium, bicarbonate and inorganic phosphate were determined continuously after stimulation of salivary secretion by pilocarpine. The electrolyte concentrations showed a marked dependence on salivary flow rate. Sodium, calcium and bicarbonate concentrations and pH increased with increasing flow rate but the concentrations of potassium, magnesium and inorganic phosphate decreased with increasing flow rate. In general salivary electrolyte concentrations showed a tendency to approach plasma concentrations with increasing flow rate with the exception of the salivary magnesium concentration, which fell below its plasma level and bicarbonate which exceeded the plasma concentration. The results will be considered as a basis of further investigations on electrolyte excretion patterns in patients with hormonal and metabolic disturbances.

Autoradiographic investigation on the cell kinetics of crypt epithelia in the jejunum of the mouse. Confirmation of steady state growth with constant frequency distribution of cells throughout the cycle.

Abstract: Cell kinetic parameters of cells in the crypt of the jejunum of the mouse were obtained autoradiographically. A number of different methods used in cell proliferation studies were applied to the same animal strain kept under constant conditions. In order to avoid effects of geometrical factors, squashes of isolated crypts were used. The generation time was determined by the per cent labelled mitoses method of Quastler, modified by double labelling with 3H- and 14C-TdR. This modified method permits a more exact determination of the generation time. The duration of the cycle was 14 hr. Double labelling experiments in which an injection of 3H-TdR was followed by an injection of 14C-TdR after 1 hr showed that the cell flux was 7.0%/hr at the beginning of the S-phase and 7.68%/hr at the end. Assuming steady state growth a constant cell flux of 7.15%/hr within the whole cycle can be derived from the measured generation time of 14 hr. These results clearly show that the crypt epithelia constitute a steady state system with constant frequency distribution of the cells throughout the cycle. The per cent labelled mitoses method after a single injection of 3H-TdR as well as double labelling experiments with 3H- and 14C-TdR give an estimate of the S-phase of 8.0 or 7.4 hr respectively. Double determinations lead to a value of 0.54 or 0.52 hr respectively for the duration of mitosis and to values of 77% and 72%

The effect of light and temperature of the CO2 exchange of different life forms in the ground vegetation of a montane beech forest

Abstract: In a montane beech (Fagus sylvatica) forest the influence of the climatic factors, light and temperature, on net photosynthesis and on the CO2 balance of the ground vegetation was investigated. The total turnover of carbon was calculated. Species studied included: Athyrium filix-femina, Oxalis acetosella, Luzula luzuloides, Deschampsia flexuosa and young plants of Fagus sylvatica. 1. The light compensation point in all spp. is between 300 and 500 lux except for D. flexuosa where it is 2 klx. Light saturation is attained at 2-3 klx for A. filix-femina, at 5-6 klx for O. acetosella, and at 6-7 klx for L. luzuloides and F. sylvatica. The net photosynthesis of D. flexuosa increases linearly upto 12 klx. This plant, therefore, is more closely related to plants with high light requirements than all the other species under experiment. 2. The maximum rates of net photosynthesis in O. acetosella and A. filix-femina are higher than in all the other plants, independent of the reference system. Per unit dry weight they even attain rates of CO2 uptake (22-27 mg CO2/gdw·h) known from herbs under the much better light conditions of an open habitat. F. sylvatica and L. luzuloides exhibit per unit dry weight only 30% of this rate and D. flexuosa 25%. On a leaf surface area and chlorophyll content basis differences are smaller: F. sylvatics attains 75%, L. luzuloides reaches 50% and D. flexuosa only 30% of the maximal rates of net photosynthesis of O. acetosella and A. filix-femina. The higher CO2 uptake of O. acetosella and A. filix-femina points to a better adaptation of their photosynthetic apparatus in comparison to all the other species of the same habitat. 3. At light saturation the temperature optimum of A. filix-femina and O. acetosella covers a smaller range at lower temperatures than was found in the other species. These attain almost maximal rates of net photosynthesis over the whole range of temperatures of their natural habitat. At decreasing light intensities the temperature optimum of O. acetosella changes from 13-18° C at 8-12 klx to a range of even lower temperatures (9-12° C at 1 klx). 4. The respiration of the rhizome and the roots of O. acetosella is per unit dry weight 40% of the dark respiration rate in the above ground material. 5. The daily gain of net photosynthesis per unit dry weight of O. acetosella and A. filix-femina is 4 times as high as in L. luzuloides and in F. sylvatica and 7 times as high as in D. flexuosa. Per unit of surface area and chlorophyll content differences are smaller. The sequence in all cases remains the same. During the night D. flexuosa has the highest relative respiratory loss. Its CO2 gain over 24 hours is very small. 6. The importance of sun flecks on the CO2 balance is small in all species except D. flexuosa. More important is the mean light intensity and the rate of net photosynthesis which is attained under these conditions. The amount of CO2 photosynthetically bound in sun flecks is 6% of the daily balance in A. filix-femina, 16-19% of the daily balance in O. acetosella, L. luzuloides and F. sylvatica, and 27% of the daily balance in D. flexuosa. The existence of D. flexuosa is dependent on the occurrence of sun flecks on the forest floor. The ecological significance of the relative light intensity in the mosaic-like distribution of plants on the forest floor is discussed. 7. The varying success in adaptation to the conditions of the habitat becomes even more evident when compared with the primary production of the beech crown. The daily gain of net photosynthesis of O. acetosella and A. filix-femina per unit dry weight is much larger than in either the sun or shade leaves in the canopy of the same stand. Per unit surface area of the leaves they attain 18-20%, per unit chlorophyll content 32% (L. luzuloides and the young plants of F. sylvatica 16-27%, D. flexuosa 4%) of the gain of net photosynthesis in the beech sun leaves. 8. A comparison with a model of primary production (maximal rates of net photosynthesis under experimentally optimal conditions over the whole day = 100%) shows what effect the different climatic factors of the natural habitat have in limiting the CO2 balance, and to what extend the actual CO2 gain reaches the physiological optinum. On the forest floor the rate of net photosynthesis is reduced primarily through the intense shade of the beech canopy and by dawn and dusk (reduction of the maximal CO2 gain in O. acetosella and in A. filix-femina ca. 50%, in L. luzuloides and F. sylvatica ca. 60% and in D. flexuosa ca. 86%). The effect of additional clouds is smaller (reduction of the maximal CO2 gain in all species 4-6%, maximal 19%). The effect of temperature is very small for L. luzuloides, F. sylvatica and D. flexuosa. Corresponding to the low temperature optimum the influence of the prevailing temperatures is much higher in O. acetosella and A. filix-femina (4-6% reduction of the maximal CO2 gain through temperatures above optimum). 9. For an assessment of the competition potential of O. acetosella compared to L. luzuloides and F. sylvatica for the vegetation period of April to August, the carbon balances of the whole plants were estimated. These are compared with the dry weight increase. Among the three life forms of the rhizome geophyte (Oxalis), the hemicryptophyte (Luzula) and the phanerophyte (Fagus) there are striking differences in the use and in the distribution of the CO2 gain. L. luzuloides invests 65% of the net photosynthetic gain as dry weight increment (O. acetosella only 44%, F. sylvatica 40%). Moreover, the growth of L. luzuloides takes place primarily above ground with the establishment of new leaves. The relative proportion of the growth above ground to the total dry weight increment is for L. luzuloides 63%, as against 57% in F. sylvatica and only 42% in O. acetosella. In respect to the total carbon balance the better use of the CO2 gain gives L. luzuloides in this habitat a higher competition potential than the photosynthetically more active O. acetosella. The constitutional differences in the photosynthetic activity are compensated for by the distribution of the assimilates to shoot and root.

[Growth and regeneration in parenchymatous organs of the rat. Autoradiographic investigations with 3 H-thymidin].

Abstract: Die sowohl nach singularer 3H-Thymidin-Injektion als auch nach kontinuierlicher 3H-Thymidin-Dauerinfusion an Ratten erhobenen autoradiographischen Befunde lassen folgende Schlusse ziehen:

Extreme water stress and photosynthetic activity of the desert plant Artemisia herba-alba asso.

Abstract: During the dry season in the Negev desert (Israel) Artemisia herbaalba in its natural habitat has a very low water content. It shows values of negative hydrostatic pressure in the xylem down to -163 bars and an extreme of osmotic potential in the leaves of -92 bars. The diurnal water stress does not decrease strongly in the night. Under these conditions Artemisia is still photosynthetically active for a few hours of the day during the whole dry period.

Trimethylphosphin‐Komplexe von CuCl und AgCl: Darstellung, NMR‐ und NQR‐Spektren

Abstract: Aus (CH3)3P und CuCl bzw. AgCl wurden tetramere Verbindungen der Zusammensetzung [(CH3)3PMCl]4, Dimere der Formel {[(CH3)3P]2MCl}2, Monomere [(CH3)3P]3MCl und instabile, vermutlich ionisch aufgebaute Komplexe des Typs [(CH3)3P]4M⊕Cl⊖ erhalten (M Cu, Ag). Diese Koordinationsverbindungen wurden mit Hilfe der IR-, 1H-NMR-, 35Cl- und 63Cu-NQR-Spektroskopie naher charakterisiert und die Ergebnisse vergleichend diskutiert. Trimethylphosphine Complexes of CuCl and AgCl: Synthesis, N.M.R. and N.Q.R. Spectra Tetrameric complexes [(CH3)3PMCl]4, dimeric species {[(CH3)3P]2MCl}2, monomeric [(CH3)3P]3MCl, and unstable, probably ionic compounds [(CH3)3P]4M⊕Cl⊖ have been obtained from (CH3)3P and CuCl or AgCl, resp. (M Cu, Ag). These new compounds were characterized by i.r., 1H n.m.r., 35Cl and 63Cu n.q.r. spectra and the results compared and discussed.

A digital registration system for net photosynthesis and transpiration measurements in the field and an associated analysis of errors.

Abstract: A digital registration system used with temperature- and humidity-controlled cuvettes for net photosynthesis and transpiration measurements in the field is described. The associated errors of the measured parameters and calculated data are estimated. The digitalization is based on an analogue registration which is of primary importance in the control of experimental conditions in the cuvettes. The digital system is connected to the analogue registration in series. The error associated with digitalization is 0.1% across 70% of the scale. This error increases to 0.2% between 3 and 30% on the scale due to a minor lack of linearity. The reproducibility of the digitalization is ±0.024%.The error associated with data transfer in the digitalization and the errors of the analogue registration are estimated for temperature and humidity measurements (error of air and leaf temperature is ±0.1° C; error of the dew point temperature is ±1.1° C dew point). The effect of these errors on the calculation of relative humidity and the water vapour difference between the leaf and the air is determined using the progressive error law. At 30° C and 50% relative humidity, the error in relative humidity is ±7.4%, the error for the water vapour difference is ±6.6%. The dependence of these errors on temperature and humidity is shown.The instrument error of the net photosynthesis measurement is calculated to be ±4.2%. Transpiration measurements have an average inaccuracy of ±8.3%. The total diffusion resistance which is calculated from values of transpiration and the water vapour difference has an average error of ±10.9%. The sizeable influence of errors in humidity and temperature measurements on the calculated diffusion resistance is demonstrated. The additional influence of biological errors associated with field measurements is discussed.

Wirkung von K + auf die Fluxe und den Transport von Na + in Gerstenwurzeln, K + -stimulierter Na + -Efflux in der Wurzelrinde

Abstract: Barley roots grown on a nutrient solution containing 1 mM Na+ but no K+ are capable of a considerable Na+ transport via the symplasm of the root and the xylem vessels. K+ added to the medium surrounding the root cortex severely inhibits this transport after a lag period at a high rate constant (Fig. 3).

Cytomorphologische und morphometrische Studien der Hepatocarcinogenese

Abstract: Das Cytoplasma Nitrosomorpholin(NNM)-vergifteter Hepatocyten (Ratte) wird in langfristigen Stopversuchen, am Ende einer 7–9 wochigen Vergiftungsphase (12 mg NNM ad 100 ml Trinkwasser) sowie 4, 52, und 61–87 Wochen danach, morphologisch und morphometrisch untersucht. Dabei sind 4 Gruppen von Cytoplasmaalterationen (CyA) gegeneinander abzugrenzen, die fur bestimmte cellulare Schadigungstypen kennzeichnend sind: 1. Reversible toxische CyA (Glykogenschwund und Ergastoplasmadisorganisation), 2. persistierende toxische und posttoxische —d. h. erst nach Absetzen des NNM auftretende —CyA (ubermasige Glykogenspeicherung und Hypertrophie des agranularen endoplasmatischen Reticulums), 3. passagere posttoxische CyA (Verfettung) und 4. progrediente posttoxische CyA (Glykogenreduktion und relative Ribosomenvermehrung). Das Ausmas dieser Cytoplasmaveranderungen last sich z. T. durch morphometrische Bestimmung der Zellflachen (gemessen an der Kernzahl in definierten Blickfeldern) genauer erfassen. Die Ermittlung des prozentualen Anteils der einzelnen cellularen Schadigungstypen an der jeweiligen Gesamt-population gibt zudem Hinweise auf den Mechanismus der Zelltransformation. Die Ergebnisse stutzen die fruher schon geauserte Ansicht, das der Hepatombildung eine persistierende hepa-tocellulare Glykogenose vorausgeht. Hauptmerkmal der Zelltransformation ist eine allmahliche Glykogenreduktion, die im Stopversuch unabhangig von einer weiteren Einwirkung des Carcinogens ablauft. Die Zelltransformation ist demnach keine unmittelbare Folge der Intoxikation, sondern eine Reaktion der Zelle auf die primare toxische Lasion.

Organogold‐Chemie. X. Methylgold(I) und Gold(I)‐halogenide als komplexbildende Zentren für Trimethylphosphin und Trimethylphosphit

Abstract: Methylgold(I) bildet mit Phosphinen und Phosphiten nur 1 : 1-Komplexe, wahrend Gold(I)-halogenide ebenso wie Gold(I)-nitrat und -tetrafluoroborat zusatzlich 1 : 2- und 1 : 4-Komplexe aufzubauen vermogen. Von diesen kommt den 1 : 2-Verbindungen im festen Zustand und in wasriger Losung eine ionische Struktur mit linearer Ligandenanordnung am Kation zu. Die vermutlich tetraedrischen Komplex-Kationen der 1 : 4-Verbindungen verlieren leicht Phosphin, um in die 1 : 2-Komplexe uberzugehen. – Alle Verbindungen wurden IR- und NMR-spektroskopisch untersucht. Die im System H3C – Au/P(CH3)3/P(OCH3)3 besonders gunstigen Voraussetzungen erlaubten eine einfache NMR-spektroskopische Bestimmung der Gleichgewichtskonstanten fur die Ligandenaustauschreaktion nach Gl. (2). Organogold Chemistry, X. Trimethylphosphine and Trimethylphosphite as Ligands to Methylgold(I) and Gold(I) Halides Trimethylphosphine as well as trimethylphosphite only form 1 : 1 complexes with methylgold. With gold(I) halides, nitrate, and tetrafluoroborate, 1 : 2 and 1 : 4 complexes can also be obtained. The 1 : 2 compounds are assigned an ionic structure with a linear arrangement of ligands in the cation of the solid and of the aqueous solutions. The 1 : 4 compounds, which are likely to possess tetrahedral AuP4-cations, lose phosphine readily and are converted to the 1 : 2 complexes. All compounds were studied by infrared and n.m.r. spectroscopy. Favourable conditions with the system H3C–Au/P(CH3)3/P(OCH3)3 allow a straightforward determination of the equilibrium constant for the ligand exchange reaction according to eq. (2), using n.m.r.

Entwicklungsleistungen abdominaler Imaginalscheiben vonCalliphora erythrocephala (Insecta, Diptera). Experimentelle Untersuchungen zur Morphologie des Abdomens

Abstract: Um ihre Differenzierungsleistungen zu bestimmen, wurden abdominale Imaginalscheiben erwachsener Larven der SchmeisfliegeCalliphora erythrocephala thermokauterisiert, exstirpiert bzw. in gleichaltrige Wirte implantiert. Die Experimente erlauben Aussagen (a) zur Morphologie des Imaginalabdomens und (b) zum Problemkreis der „regulatorischen Aktivitatzwischen Imaginalscheiben“.

A new type of climatized gas exchange chamber for net photosynthesis and transpiration measurements in the field

Abstract: A temperature- and humidity-controlled plant chamber for CO2 and H2O exchange measurements in the field is described in which the heat exchanger assembly and humidity controlling water vapour trap are separated from the plant cuvette. The shape and construction material of the plant cuvette can vary according to the demands of the experimental conditions and the size and growth form of the plant. The natural illumination field is only slightly altered in this plant cuvette. In the chamber, the temperature and humidity conditions can either be held constant throughout a wide range of conditions or can be programmed to track ambient condition. In this manner, not only temperature and absolute humidity are replicated, but it is also possible to reproduce the natural conditions of water vapour gradient between the evaporating surfaces in the mesophyll and the atmosphere, the relative humidity of the air, and the temperature difference between the leaf and the ambient air. Thus, the chamber appears to be an appropriate instrument to investigate with sufficient accuracy the reactions of individual plants in cultivation or in natural communities under field conditions.

Experiments on Pattern Discrimination in Honey Bees

Abstract: Honey bees can discriminate between different n-painted stars (fig. 1) offered on a horizontal plane. If 2 of the 4 parameters are constant within one series of shapes, the results can be described by at least one of these different parameters uniquely (figs. 3, 4, 5). If only one of these values remains constant, one simple parameter does not describe the results (fig. 6a) as expected after earlier experiments.