false

1980

Compression creep and stress-relaxation tests have been performed on PMMA at several deformations after the sample yielding. At large loading rates, the behaviour observed was found significantly affected by the temperature rise due to the plastic deformation. Creep and stress-relaxation data taken holding the samples at constant temperature after the material loading could be collected into single curves by means of a time shift factor proportional to the loading rate. Retardations- und Relaxationsuntersuchungen bei Druckbeanspruchung von PMMA wurden bei verschiedenen Deformationen oberhalb des Fliespunktes durchgefuhrt. Bei hohen Beanspruchungsgeschwindigkeiten wurde festgestellt, das das…

EFFECT OF MOISTURE ON THE BULK PROPERTIES OF SALTED POLY(CAPROAMIDE).

1980

The glass-transition temperature (Tg) and the elastic modulus of nylon-6 and its mixtures with 4% w/w LiCl and with 2% LiCl+3% LiBr were investigated. In one set of experiments care was taken to avoid absorption of moisture during the measurements. In another set of experiments, samples were exposed to atmospheric humidity for different lengths of time. Both unoriented and oriented specimens were investigated. The presence of 4% LiCl almost doubles the amount of moisture absorbed at equilibrium by nylon-6. The Tg was found to be greatly affected by the moisture content and by salt type. When strict precautions to exclude moisture are taken, the addition of 4% LiCl raises the Tg of nylon-6 b…

Die thermische polymerisation von methylmethacrylat, 3. Verhalten des ungesättigten dimeren bei der polymerisation

1980

The thermal polymerization of methyl methacrylate is accompanied by the formation of appreciable amounts of an unsaturated dimer (H-1). The behaviour of H-1 during homopolymerization in presence of an initiator at 60, 80 and 100°C and during copolymerization with MMA in presence of an initiator at 60°C are investigated. The rate of (H-1)-homopolymerization is very low. The transfer constant to monomer H-1 is about CH-1 = 3·10−3 at 80°C as received from Pn-determinations. The termination is essentially by disproportionation. The copolymerization parameters as resulting from polymerizations with labeled MMA at 60°C are rMMA = 1,8 and rH-1 = 0,33, respectively.

LOW BIRTHWEIGHT REVISED

1980

The location by early auditory evoked potentials (EAEP) of acoustic nerve and brainstem demyelination in multiple sclerosis (MS).

1980

Tone pips of suprathreshold intensities elicit an acoustic nerve response (I) and six low amplitude brainstem potentials (II-VII) during the initial 10 ms. Seven waves were studied in 40 control subjects and 5 waves (I-V) in 47 patients with MS. The results suggest involvement of the auditory pathway of 24 of 27 patients in the clinically "definite", of 5 of 9 cases in the "probable" and in none of 5 patients in the "possible" MS groups. EAEPs were normal in 6 cases with a spinal form with one exception where changes of potential were indicative of a midbrain lesion. Dysfunction within the acoustic pathway was observed at the level of the acoustic nerve and in the medulla oblongata, pons an…

false

1980

Migration of Leukocytes into Filters Coated Homogeneously with Immune Complexes, Antigens, Lectins or Tripeptides

1980

Cellulose nitrate filters were incubated in solutions of albumin, a chemotactically active tripeptide (f-Met-Leu-Phe), immune complexes or lectins and afterwards washed with buffer. They showed a dose-dependent increased leukocyte migration, when tested in typical Boyden chambers in comparison to filters treated only with buffer. The tripeptide, the immune complexes and the lectins were stimulatory at very low concentrations and acted inhibitory at high concentrations. Treating filters with formaldehyde or glutardialdehyde had no clear stimulatory effect. These findings extend earlier observations obtained with casein. They show that cells move very effectively on solid substrata in the abs…

Vesico-uterine fistula treated by amenorrhoea induced with contraceptive steroids. Two case reports.

1980

2 case reports of women with vesico-uterine fistulae who were successfully treated by inducing amenorrhea by the continuous administration of an estrogen-progestogen compound for 6 months are presented. Ortho-Novum 1/50 was used. The amenorrheic condition induced by continuous ingestion of an oral contraceptive agent allowed the fistula time to heal since fistulae rarely close spontaneously because of fluids flowing fhrough them inhibiting the healing process. This method of management should be tried before surgery the generally recommended treatment.

Una estimacion de la funcion de produccion ces generalizada mutivariante

1980

International audience; La función de producción CES generalizada ha sido ya objeto de numerosos trabajos econométricos. Pero hay que senalar que el econometra se ha centrado principalmente en resolyer el problema bidimensional clasico, capital-trabajo, sin abordar el caso multidimensional de esta relacion técnica, a excepcion, sin embargo, de los trabajos de generalizacion del anaIisis de transformadon de BOX y COX ( 1 ). El método que proponemos aqui es una extension multivariante del procedimiento de KMENTA (2), que exige la introduccion de restricciones no lineales implicitas en los. parametros de la forma estructural del mo4elo, con el fin de garantizar las cofidiciones de identificaci…

The effect of indole-3-acetic-acid on the photosynthetic apparatus of Sinapis alba

1980

The influence of indole-3-acetic-acid (IAA) during the development of primary leaves of Sinapis alba was studied. IAA treatment (4 ppm ≈ 22.8 μM) caused a decrease of dry weight, soluble reducing sugars, soluble protein, chlorophylls, carotenoids and cytochrome f; it also caused a lower ratio of protein to chlorophyll, a lower ratio of chlorophyll a to chlorophyll b and a higher ratio of chlorophyll per cytochrome f. Furthermore, IAA treatment induced a significantly lower rate of CO2 fixation and a depressed nitrite reductase activity. Similar effects could also be observed in adaptation reactions brought about by red light and low-light (or shade) conditions.

On localization of moving objects in the visual system of cats.

1980

In cortical areas direction-specific receptive fields occur systematically. Direction specifity is based on unsymmetric coupling of neurons. Such a coupling allows an exact localization of moved stimuli. For this task, the asymmetry in the time domain is compensated for by a spatial asymmetry.

Isolation and characterization of a chlorogenic acid esterase from Aspergillus niger.

1980

Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split…

Development of antennal sensilla during moulting inNeomysis integer (Leach) (Crustacea, Mysidacea)

1980

The sensilla are associated with 6 enveloping cells. The innermost enveloping cell (e 1) secretes the dendritic sheath (=thecogen cell). All other enveloping cells are involved in the formation of the outer cuticular apparatus in secreting the cuticle of a definite region of the new hair shaft. The development of the new sensilla begins when an exuvial space expands between old cuticle and epithelium. The newly forming hair shafts lie folded back in an invagination of the epidermal tissue. Only a distal shaft part projects into the free exuvial space. The cuticle of the distal and middle shaft region is secreted by the three middle enveloping cells (e 2–e 4) (=trichogen cells), which are ar…

Assessment of various factors influencing esophageal pressure measurement

1980

Die intraluminale Manometrie wird zunehmend fur die Diagnose osophagealer Motilitatsstorungen eingesetzt. Die klinische Validitat der Methode hangt jedoch entscheidend von einer exakten Standardisierung der Methodik, des Untersuchungsablaufes und der Kenntnis der Einflusgrosen auf das Mesergebnis ab. Im ersten Teil dieser Studie wurde der Einflus verschiedener methodischer Faktoren auf das Ergebnis der Osophagusdruckmessung in Modellversuchen, bei 44 gesunden Probanden und bei 74 Patienten mit axialer Hiatushernie mit einem elektromagnetischen Mikrotransducer untersucht. Signifikante Unterschiede der Meswerte fanden sich in Abhangigkeit von der Sensorposition im oberen Osophagussphinkter (p…

T-cell-derived helper factor allows in vivo induction of cytotoxic T cells in nu/nu mice

1980

T-cell immunocompetence and diversity are thought to be generated in the thymus1,2. This view is based on the findings that (1) T-cell ontogeny is thymus dependent3,4, (2) the major histocompatibility restrictions of T-cell interactions are phenotypically related to the H–2 type of the thymus5–9, and (3) the phenotypic manifestation of H–2-linked immune responsiveness parallels the restriction elements selected in thymus10–12. However, it is unclear whether pre-thymic cells programmed to develop into T cells do already express a receptor diversity, also whether pre-thymic cells have the potential to react against self-antigens, and whether the mechanism of self-tolerance is initiated in the…

Fetal rhabdomyomatous nephroblastoma. Pathologic histology and special clinical and biologic features.

1980

Fetal rhabdomyomatous nephroblastoma is a very rare variant of Wilms' tumor. The special clinical and histologic features of this variant are presented on the basis of a case seen in a boy who was 13 months old at nephrectomy 8 months ago and has remained healthy since then. The tumor chiefly consists of fetal striated muscle; it occurs predominantly in infancy and early childhood and is often bilateral. Angiography shows a relative paucity of vessels. The volume of the tumor (determined by ultrasonography) decreases only slightly after preoperative radio- and chemotherapy because of a predominance of mesenchymal structures. The finding of nodular renal blastema in renal parenchyma with an …

Intestinal filtration as a consequence of increased mucosal hydraulic permeability

1980

Two mechanisms have been proposed to explain the secretory action of laxative compounds in the intestine: 1. increase of the intracellular amount of cyclic adenosine monophosphate due to stimulation of the adenylate cyclase system and 2. inhibition of intestinal transfer processes, in particular the Na,K-ATPase activated sodium absorption. In a set of in vivo and in vitro experiments in rat colon it could be demonstrated that dihydroxy bile acids (deoxycholate) and diphenolic laxatives (oxyphenisatin) enhance the hydraulic permeability of the mucosal tissue. The permeability changes take place--and there is good experimental evidence--at the zonulae occludentes which bind the epithelial cel…

Calculation of proton activity in aqueous protolyte solutions

1980

Abstract A general and thermodynamically exact equation for the calculation of the proton (hydroxide ion) activity of aqueous solutions of monoprotic acidic (and basic) species is given. Under certain conditions, various approximate equations can be derived from the exact form; the applicability of these depends mainly on both the thermodynamic equilibrium constant, K p , of the protolytic reaction, and the stoichiometric concentration, C o , of the protolyte. Taking into account the mean ionic activity coefficients which are calculated by means of the Davies equation, diagrams are constructed exhibiting those combinations of K p and C o for which the respective approximations can be applie…

Gallstone dissolution with chenodeoxycholic acid. A clinical study.

1980

Out of 95 patients with radiolucent gallstones who enrolled in a clinical study with chenodeoxycholic acid (CDC) for gallstone dissolution 75 patients with cholecystolithiasis completed 12 months of treatment. As a side effect 31% of patients reported intermittent diarrhea which did not cause cessation of therapy or missing of work. The incidence of biliary colic was markedly decreased during treatment in comparison to the rate in the year before. From more than 20 laboratory values checked before start and every 3 months during therapy only aminotransferases increased up to 3 fold in 20% of patients. gamma-GT elevated in 31% of patients before treatment improved in half of these patients d…

Selective, homogeneous hydrogenation of cycloheptatriene to cycloheptene catalyzed by (η4-cycloocta-1,5-diene)(η6-cyclohepta-1,3,5-triene)ruthenium(0)

1980

Abstract In the presence of small amounts of [Ru(η 4 -COD)](η 6 -C 8 H 10 )] (1), cycloheptatriene is hydrogenated to cycloheptene, under one atmosphere of hydrogen at room temperature in homogeneous phase. The formation of a small amount of cyclooctene and the existence of an induction period, which do not occur when [Ru(η 4 -COD)(η 6 -C 7 H 8 )] (2) is used as the catalyst, suggest that 2 is the real catalyst. The selectivity of this hydrogenation is 100% in n-hexane as solvent, 99.5% in THF, and low in ethanol. Conversion is quantitative in THF and ethanol, but not more than 65% in n-hexane. In the presence of 1 or 2, cycloheptene is rapidly hydrogenated to cycloheptane in THF and ethano…

Photoproduction of pions at low energy

1980

Presented in this paper is a field theory model for photoproduction of pions at low energy. In particular, it is shown that certain interaction terms, which were previously considered to be essential in order to explain the experimental situation corresponding to the spin-3/2 resonances, are really unnecessary and that the presence of these terms are not justifiable from the theoretical point of view. Further, the free parameters in the theory representing the off-mass-shell effects of the spin-3/2 particles are fixed on the basis of theoretical considerations.

Calculation of small-angle neutron scattering by macromolecules in the semicrystalline state

1980

The conformation of macromolecules in the semicrystalline state has been studied by various authors with respect to the validity of the adjacent re-entry — or switchboard model by application of small-angle neutron scattering. Analytical as well as Monte-Carlo calculations show that the experimental results for melt crystallized polyethylene and isotactic polypropylene can be interpreted on the basis of the solidification model. In this model it is assumed that crystallization occurs by straightening of coil sequences without a long range diffusion process.

The effect of cathartic agents on transmucosal electrical potential difference in the human rectum.

1980

Active ion transport in the colon is generating a transmucosal electrical potential difference (PD) of about 40 mV. Cathartic agents inhibit electrolyte and water net-absorption or cause net-secretion which should be reflected in a change of PD. In 83 normal subjects the effect of an isotonic eletrolyte solution (control) and different cathartic agents on rectal PD was tested: Laxatives (bisacodyl, rhein), bile acids (cholic and deoxycholic acid), fatty acids (oleic and ricinoleic acid) and cardiac glycosides (meproscillarin, digitoxin, digoxin). Bisacodyl, deoxycholic acid in high concentration, meproscillarin and digitoxin significantly decreased PD, while the other substances did not. Ca…

Enantioselektive Trifluoracetylierung mit Hilfe chiraler Polyamide

1980

(S)-Poly(2-aminobutyric acid) (1) [(S)-poly(imino-1-methyl-3-oxotrimethylene)] was transformed into its N-trifluoroacetyl derivative 4. The IR spectra and the circular dichroism of both substances were compared. In addition, (S)-poly[N-(1-phenylethyl)acrylamide] (2) ((S)-poly-[1-(1-phenylethylaminocarbonyl)ethylene]) was trifluoroacetylated leading to polymer 5. 4 was found to react as trifluoroacetylating agent with L-1-phenylethylamine (L-3) twice as fast as it reacts with D-3. Accordingly, the reaction of 4 with D,L-3 leads preferentially to the L-form of N-(1-phenylethyl)trifluoroacetamide with optical yields up to 6%. The reaction of 5 with D,L-3 affords the D-form of N-(1-phenylethyl)…

Die digitiformen Sensillen auf dem Maxillarpalpus von Coleoptera

1980

The digitiform sensilla on the distal segment of the maxillar palps ofAgabus bipustulatus (L.) andHydrobius fuscipes (L.) were investigated by electron microscopic methods. Each sensillum is innervated by a single bipolar sensory cell. The sensilla ofHydrobius are associated with three enveloping cells, which enclose an inner and outer receptor lymph cavity. A single enveloping cell only is found in the completely differentiated sensilla ofAgabus. These sensilla do not form an outer lymph cavity. The area beneath the hair base is filled by the distal process of the enveloping cell and by extensions of epidermal cells. Only one extra-cellular space exists, which seems to be homologous to an …

A direct determination of the proton electron mass ratio

1980

The cyclotron frequencies of free protons and electrons in a magnetic field of 5.81 Tesla with superimposed electrostatic quadrupole field have been measured. The increase of energy connected with a transition at cyclotron frequency is detected by the measurement of the time of flight through an inhomogeneous magnetic field. From the ratio of the measured cyclotron frequencies of both particles the proton electron mass ratio is deduced. The resultm p /m e =1,836.1527(11) agrees within the limits of error (0.6 ppm) with the value of the indirect determination.

Biochemical Characterization of an Acetylcholine-hydrolyzing Enzyme from Bean Seedlings.

1980

An acetylcholine hydrolyzing enzyme was prepared and purified (40 times) from dwarf bean hypocotyl hooks. The purity of the enzyme was proved by polyacrylamide gel electrophoresis. The molecular weight of the enzyme was determined to be 65,000 daltons. Enzyme activity was the highest at pH 8.0 and between 30 and 36 C. The enzyme had an apparent affinity constant (K(m)) for acetylcholine of 460/micromolar. The affinity for substrate analogs increased from butyrylthiocholine to propionylthiocholine to acetylthiocholine. The enzyme activity was inhibited by choline, neostigmine, physostigmine, manganese, and calcium. Magnesium had no influence on the enzyme activity. We conclude that the enzym…

Veränderungen der Schmelzoberfläche bei der Klebetechnik

1980

An 11 aus kieferorthopadischen Grunden zu extrahierenden Zahnen wurden vestibular und oral mit Hilfe der Klebetechnik Kunststoffbrackets befestigt. 12 Wochen danach wurden diese Zahne extrahiert, in Einzelschnitte von 100 nµ Dicke zerlegt und polarisationsoptisch untersucht. Dabei wurden regelmasig im Zervikalbereich der Klebestelle Demineralisationen festgestellt.

Mise en évidence d'une production de protéases exocellulaires par les levures au cours de la fermentation alcoolique du moût de raisin

1980

<p style="text-align: justify;">La durée d'activité très limitée dans le temps des protéases du raisin est confirmée en vinification en blanc, mais une nouvelle activité protéolytique peut être caractérisée à 37 °C et à pH 3,7 dans le moût au cours de la fermentation alcoolique.</p><p style="text-align: justify;">Cette activité doit être attribuée à des protéases exocellulaires libérées dans le milieu des levures. Parmi les souches essayées <em>S. bayanus</em> a une activité protéolytique plus importante que <em>S. cerevisiae</em>, ce qui se traduit par l'obtention de vins plus riches en azote soluble, donc plus stables du point de vue protéique et …

Vergleichende Untersuchungen über die Häufigkeit von Zahnstellungs- und Kieferanomalien bei Patienten mit Deformitäten der Wirbelsäule

1980

Value and limits of computer-assisted tomography.

1980

Three years ago, at the VIIth International Congress of Radiology in Otorhinolaryngology, held in Copenhagen, the early impressive results of computer-assisted tomography (CAT) in otorhinolaryngology were presented. Since considerable technologic and diagnostic progress of CAT has taken place in the meantime, questions about the increase in CAT's value and the expansion of its limits are appropriate now. Computed and, in some cases, conventional tomograms of facial lesions are used in the discussion of these questions. There is no doubt of CAT's advance within the last few years; there are, however, limits of CAT to be emphasized: (a) coronal CAT might be uncomfortable (especially if the ga…

Assessment of various factors influencing esophageal pressure measurement. II. Significance of physiological factors in intraluminal manometry.

1980

In the second part of this study the effect of age, sex, body size, body weight and timing of the manometric examination (morning vs. noon) on esophageal pressure measurement was investigated in a total of 119 healthy subjects, using an electromagnetic microtransducer. Additionally intraindividual variation of pressures was studied over a period of 6 months. Of these parameters only age influenced upper esophageal sphincter (UES) pressure significantly: The mean UES pressure of younger subjects (20-49 years) was significantly higher (144.4 +/- 8.6 mmHg) compared to that of older subjects (50-80 years) where a mean pressure of 103.4 +/- 7.2 mmHg was recorded (p less than 0.0005). Intraindivi…

Dielectric behaviour of a γ-irradiated polycarbonate

1980

Dielectric measurements on a γ-irradiated polycarbonate in a dose range 0–20 Mrad and at test frequencies of 103 and 104 Hz have been carried out. The glass transition temperature shows a maximum at 3.5 Mrad and then decreases at larger doses. This result is in line with other experiments (intrinsic viscosity, dynamic-mechanical measurements, etc) already reported: the Tg values are however larger in the present results. This is probably due to the plasticizing action of the absorbed moisture present in the previous tests. A Tg vs 1/[n]2 plot (1/[n]2 is proportional to 1/m ) allows to find the value of the glass transition point at an infinite molecular weight and the dependency of Tg on mo…

Beta-delayed neutrons and high-energy gamma-rays from decay of137I

1980

Beta-delayed neutrons and high-energyγ-rays following decay of137I have been studied in order to characterizeβ-decay to and deexcitation of neutron-unbound levels in137Xe. The totalγ-ray intensity observed accounts for at least 20% of theβ-intensity to levels aboveB n . No evidence was found for neutron andγ-ray emission from the same levels. With the experimentalβ-strength function aboveB n detailed tests were performed on the reproduction of the experimental neutron spectrum, the level density and Porter-Thomas fluctuations of the reducedβ-transition probabilities to highly excited states in137Xe.

Produktintegration mit nicht-�quidistanten St�tzstellen

1980

For the numerical evaluation of $$\int\limits_a^b {(t - a)^{\alpha - 1} x(t)dt}$$ , 0<?<1 andx `smooth', product integration rules are applied. It is known that high-order rules, e.g. Gauss-Legendre quadrature, become `normal'-order rules in this case. In this paper it is shown that the high order is preserved by a nonequidistant spacing. Furthermore, the leading error terms of this product integration method and numerical examples are given.

Distribution of radioactive elements in three progressively metamorphosed pelite series of the Bohemian Massif

1980

The variations of the content of radioactive elements in pelitic rocks in dependence on the grade of metamorphism were studied in three regions of the Bohemian Massif with a different character and age of metamorphism. The concentrations of Th, U and K were determined by gammaspectrometric method, the major elements Si, Ti, Al, Fe, Mn, Ca, K, P by the X-ray fluorescence method. An increasing mobility of radioactive elements was found with the help of variation diagrams in the higher stages of metamorphism, the migration being apparent especially for Th and usually starting in the garnet or biotite zone. A significant negative correlation of both Th and U content with the content of SiO2 was…