Showing papers by "University of Hamburg published in 1971"

Die Bestimmung optischer Konstanten von Metallen durch Anregung von Oberflächenplasmaschwingungen

Abstract: A method is given to determine accurately the optical constants and the thickness of thin films when the real and the imaginary part of the dielectric constants obey the condition ɛ r <- 1, ɛ i ¦ɛ r ¦. The method makes use of the possibility to excite surface plasma waves with the help of the inhomogeneous light wave obtained by total reflexion. The accuracy of the method is pointed out. As an example the optical constants of silver foils in the wavelength interval 4000 to 6000 A are determined.

Local observables and particle statistics. II

Abstract: Starting from the principles of local relativistic Quantum Theory without long range forces, we study the structure of the set of superselection sectors (charge quantum numbers) and its implications for the particle aspects of the theory. Without assuming the commutation properties (or even the existence) of unobservable fields connecting different sectors (charge-carrying fields), one has a particle-antiparticle symmetry, an intrinsic notion of statistics for identical particles, and a spin-statistics theorem. Particles in “pseudoreal sectors” cannot be their own antiparticles (a variant of Carruthers' theorem). We also show how scattering states and transition probabilities are obtained in this frame.

On the anatomy of Asian Bamboos, with special reference to their vascular bundles

Abstract: A comparative histological investigation of 52 bamboo species from 14 genera, collected in seven Asian countries, was carried out; 1200 internodes from 250 culms were examined therein. The anatomical structure of the culms is characterized exclusively by the collateral vascular bundles embedded in parenchymatous ground tissue which exhibits four basic types. A classification system was devised for these vascular bundle types and their combinations within the culm; it was found to correlate well with the system of Holttum based on the structure of the ovary. A comprehensive description of the marked variability of the vascular bundle structure within one culm and between culms of a single species is given. The implications of such a representative description of a singles pecies and the introduction of an identification key are discussed.

A new definition of singular points in general relativity

Abstract: To any space time a boundary is attached on which incomplete geodesics terminate as well as inextensible timelike curves of finite length and bounded acceleration. The construction is free ofad hoc assumptions concerning the topology of the boundary and the identification of curves defining the same boundary point. Moreover it is a direct generalization of the Cauchy completion of positive definite Riemannian spaces.

Genetic interpretation of regressive evolutionary processes: studies on hybrid eyes of two astyanax cave populations (characidae, pisces).

Abstract: In a series of central Mexican limeormes, the extremely ubiquitous Astyanax stone caves several populations of cavermexicanus advanced farthest north and tonicolous characins are found, which are day it has crossed the Rio Grande into members of one species as crosses persouthern Texas. Subsequently it gave rise formed by Sadoglu (1957) suggested. Into several hypogean populations during the dividuals of these cave populations are Pleistocene age. pale and have reduced eyes. They do not The extent to which cave systems of differ very much phenotypically. All may the Sierra de El Abra were connected easily be distinguished from an epigean during their history is unknown. They characin, Astyanax mexicanus (Filippi) were probably largely isolated originally, (Synonym: A. fasciatus Cuvier), which is but have become more and more interfully pigmented and has non-reduced eyes. connected (Mitchell, pers. comm.). Thus The latter type may be crossbred with the cavernicolous populations of Astyanax above mentioned cave fish and must thereevolved separately for a time at least. fore be recognized as their ancestral form. Crosses of two cave populations--that Furthermore at least one of the cave popuof La Cueva de El Pachon (Anoptichthys lations, that of La Cueva Chica, is the antrobius) and that of La Cueva de los result of secondary hybridization between Sabinos (A. hubbsi, Alvarez, 1946)-with epigean and hypogean forms (Kosswig, the epigean form were first performed 1960). and examined by Sadoglu (1957). She The caves inhabited by these fish are came to the conclusion that individuals situated in the Sierra de El Abra (central of the population of Pachon possessed a Mexico, San Luis Potosi), a small mounlarger number of degenerative genes than tain range created during the early Tertiary those of Sabinos, and concluded that the period. Mitchell (1969) assumes that the former cave fish were phylogenetically caves were ready for colonization as early older. as the mid-Tertiary period. This author's own studies have proved Myers (1966) demonstrated that the that, contrary to Sadoglu's conclusions, the characiformes, which have a pre-Tertiary number of genes responsible for eye forSouth Continental origin, being primary fresh water fish, were only able to get mation in both populations is the same to the northern part of America after a (Wilkens, 1970a). Concerning the numland bridge had been established in ber of genes involved in the formation late Pliocene times. During the whole of the melanophore system, the population Tertiary period they were stopped from of Pachon shows at least three in addition doing so by a sea barrier between North to a single gene for albinism (Sadoglu, and South America. Among the characif1955), whereas that of Sabinos shows at

Arrangement, ultrastructure, and adrenergic innervation of smooth musculature of the ductuli efferentes, ductus epididymidis and ductus deferens of man

Abstract: 1. There is a gradual proximo-distal increase in the thickness of the muscle coat of the human ductuli efferentes, duetus epididymidis and ductus deferens. Circularly arranged smooth muscle bundles predominate in the ductuli efferentes and ductus epididymidis of the caput section. Scanty strands of longitudinally and obliquely oriented smooth muscle bundles form an additional, incomplete outer muscle layer around the ductus epididymidis of the corpus. Small smooth muscle-like cells constitute the muscle elements of the upper sections of the excretory ducts (from the ductuli efferentes to the midcauda). At the transition of the corpus and cauda epididymidis ordinary large smooth muscle cells join the small contractile cells to form—in more distal sections of the cauda—a composed, thick subepithelial muscle coat. In most distal portions of the cauda, the two-layered muscle coat of the ductus epididymidis is transformed into a three-layered coat, a pattern of construction which is retained in the vas deferens. 2. Electron microscopically, three types of contractile cells are distinguished in the human ductuli efferentes and ductus epididymidis: a) contractile cells of medium transparency containing exclusively thin myofilaments (60 A in diameter), b) dark contractile cells containing bundles of thin myofilaments (60 A in diameter) and single coarse filaments (140 A in diameter), c) light contractile cells with loosely dispersed, interweaving thin and thick myofilaments. Commutual diameter changes at regular intervals are seen in individual myofilaments, giving the impression of structural periodicity not unlike that of filaments of striated muscle. Ordinary smooth muscle cells of the cauda epididymidis and vas deferens are characterized by uniformly sized, closely packed but evenly distributed thin myofilaments with numerous dense patches. 3. Fluorescence microscopy performed on formaldehyde treated freeze dried tissues reveals that the contractile cells of the ductuli efferentes in man and monkey receive a low number of single adrenergic terminal fibres penetrating the depth of the muscle coat. The adrenergic innervation of the ductus epididymidis is restricted to small peritubular nerve fascicles running contiguous to the most superficially located bundles of smooth muscle-like cells. The adrenergic ground plexus is rather wide-meshed in the proximal cauda, becomes increasingly dense in more distal cauda sections and in initial, funicular portions of the vas deferens, and reaches maximum density in abdominal parts of the ductus. Perivascular and adventitial adrenergic plexuses are well developed at arteries of the caput and corpus epididymidis in man, monkey, rabbit, guinea-pig and rat. 4. Electron microscopically, noradrenergic nerves have been identified by the presence of small granular vesicles in preterminal varicose axon dilatations. Nerve fibre swellings filled with small empty spherical vesicles have been considered to belong to “cholinergic” neurons whereas occasional varicosities equipped with some large membrane bound granules and abundant mitochondria may represent local expansions of sensory axons. 5. Neuromuscular relationships in the upper sections of excretory ducts comprise adrenergic synapses by distance (more than 1000 A), and a few intimate, ensheated close contacts, whereas the main type of contact of nerves to ordinary smooth muscle cells in the lower duct section is by means of close but not intimate approach (500–2000 A). 6. Adrenergic synapses in the ductus epididymidis and ductus deferens of the monkey resemble—what concerns their morphology, relationship to effectors and distribution pattern—those of man. 7. In accordance with the total number of vascular and non-vascular adrenergic nerves, visualized by fluorescence microscopy, the amount of noradrenaline varied considerably in different sections of the human male internal genital organs: The lowest amounts were estimated in the testis (0.12±0.03 μg/g). Medium to high concentrations were detected in various sections of the caput and corpus epididymidis (ductuli efferentes 0.60±0.09 μg/g; ductuli efferentes and caput 0.72±0.13 μg/g; corpus epididymidis 1.04±0.25 μg/g; proximal cauda 0.95±0.17 μg/g; distal cauda 0.97±0.19 μg/g). The highest noradrenaline content was found in the human vas deferens (prox. vas deferens 1.11±0.21 μg/g; interm. vas deferens 1.20±0.42 μg/g; distal portion 1.43±0.39 μg/g). 8. For comparison, the noradrenaline content of the testis and epididymis of the rhesus monkey, the epididymis of the rabbit and the vas deferens of the rabbit, mouse, guinea-pig and rat has been determined. 9. Adrenaline of exogenous origin was detected in the vas deferens, cauda epididymidis and plexus pampiniformis of two cases who received this catecholamine as part of the local anaesthetic drug mixture. Due to methodological reasons, the presence of small amounts of adrenaline of endogenous source in adrenergic nerves of the human and monkey internal male genital organs cannot be excluded. 10. The differences in motility behaviour of the ductus epididymidis (spontaneous, rhythmic contractions) and ductus deferens (absence of any spontaneous movements under conditions at rest) in vivo and in vitro have been correlated with the occurrence of specialized contractile cells in the upper segment (ductuli efferentes, ductus epididymidis of the caput, corpus and initial cauda) and ordinary large smooth muscle cells in the lower segment (ductus epididymidis of the distal cauda and the vas deferens) and furthermore correlated with differences in the pattern of the adrenergic innervation; the concept is advanced that progressive cytological differentiation of smooth muscle cells and the development of a dense direct adrenergic innervation suppresses autocontractility and, that the reverse condition may favour spontaneous motility of smooth muscle elements.

The sea surface temperature deviation and the heat flow at the sea-air interface

Abstract: The deviation of the sea surface temperature from the water temperature below is calculated as a function of the heat flow through the air-sea interface, using wind tunnel determinations of the effective thermal diffusivity in a boundary layer. The influence ofQ, shortwave radiation, andH, latent and sensible heat transfer plus effective back radiation, and U, wind speed, can be described by:T0 −Tw =C1 ·H/U +C2 ·Q/U. The calculated coefficients vary slightly with reference depth, Tables II and III. They are in good agreement with independent observations.

On the mass and momentum transfer between short gravity waves and larger-scale motions

Abstract: Interactions between short gravity waves and larger-scale flows are investigated in the two-scale approximation. The effect of the wave field on the mean flow is described by an interaction stress tensor and a surface mass transfer. The results are applied to Phillips’ and Longuet-Higgins’ model of short waves breaking on the crests of long carrier waves. It is found that the work done on the long waves by the interaction stresses (corresponding to Longuet-Higgins’ ‘maser’ mechanism of wave generation) is almost exactly balanced by the loss of potential energy arising from the mass transfer. The residual energy transfer leads to attenuation of the long waves, independent of their propagation direction relative to the short waves. Damping factors are estimated from the upwind–downwind ratios of radar backscatter cross-sections. It is found that interactions with waves shorter than 35cm yield attenuation rates about an order of magnitude smaller than the observed growth rates due to the wind.

Nichtsenkrechte Interbandübergänge in Graphit durch unelastische Elektronenstreuung

Abstract: Characteristic energy loss measurements are carried out on natural graphite single crystals. The frequency and wave vector dependent dielectric constant ɛ(ω,q) forq⊥c-axis is determined by Kramers Kronig Analysis. The results are interpreted in terms of non vertical interband transitionsE(k)→E(k+q) between the π-bands within the two dimensional approximation.

Basic two-dye stains for epoxy-embedded 0.3-1 sections.

Abstract: Dyes used in the 3 methods recommended are: I, thionin and acridine orange (T-AO); II, Janus green and Darrow red (JG-DR); III, methyl green and methyl violet (MG-MV). The first 2 methods were two-solution stains, applied in sequence; the third, required only one solution since methyl violet is present in commercial methyl green. Staining solution and timing was as follows: Method I. 0.1% thionin in a 45% ethanolic solution of 0.01 N NaOH, 5 min at 70 C; rinsing in water and followed by 1 min in a 1% aqueous solution of acridine orange made up in 0.02 N NaOH, also at 70 C, then washed, and dried on slides. Method II. 0.5% Janus green in aqueous 0.05 N NaOH, 5 min at 70 C; rinsing in water then into 0.5% Darrow red in 0.05 N NaOH (aq.), 2 min at 70 C., washing, and drying on slides. Method III. 1% methyl green (commercial, unpurified) in 1% aqueous borax for 15-20 min at 20-25 C, washing and attaching to slides. All staining was performed by floating the sections on the staining solutions, all drying at 70...

Zur Cytologie der pränatalen Gonaden-Entwicklung beim Menschen

Abstract: Es wurden die Anlagen von 16 menschlichen, embryonalen und fetalen Hoden mit dem Elektronenmikroskop untersucht. Das Alter der Embryonen reichte von 40 Tagen bis zu 22 Wochen Ovulationsalter (OA). Untersucht wurden die cytologischen Veranderungen der mannlichen Keimzelle. Dabei gelang eine eindeutige Abgrenzung von zwei Geschlechtszelltypen durch cytomorphologische Kriterie: “Gonocyten” findet man vorwiegend bis zur 12. Woche. Sie sind in einer I. Phase uberwiegend frei von Glykogen und in einer 2. Phase etwa ab dem 45. Tag OA durch zunehmende Glykogeneinlagerung im Cytoplasma charakterisiert. In einer 3. Phase ab der 10.–12. Woche treten neben den Gonocyten “fetale Spermatogonien” auf, die ab der 18. Woche etwa ein Drittel der vorhandenen Geschlechtszellen ausmachen. Fetale Spermatogonien sind an einem lockeren Kern, an der veranderten Mitochondrienstruktur, dem Auftreten von intermitochondrialer Substanz und intercellularen Brucken sowie dem Fehlen von Glykogen zu erkennen. Ein Teil dieser fetalen Spermatogonien zeigt degenerative Zellveranderungen, die als Zeichen eines spateren Zelltodes gewertet werden. Die Frage, ob Gonocyten oder fetale Spermatogonien den Zellpool darstellen, aus dem sich die Spermatogonien des postnatalen und adulten Hodens entwickeln und ableiten, wird diskutiert, kann aber mit dem vorhandenen Material und den Ergebnissen nicht beantwortet werden.

Cyclic Acyloxonium Ions in Carbohydrate Chemistry

Abstract: Publisher Summary The neighboring-group reactions studied most intensively have been those of acyloxy groups, which constitute the complex neighboring-groups. The intermediate formation of a dioxolanylium ion is invoked. The formation of such a ring between C-1 and C-2 of aldoses determines the stereochemical outcome of glycosylation reactions from glycosyl halides. Neighboring-group reactions of acyloxy groups involve a synchronous process whereby the nucleophilic oxygen atom of the carbonyl group becomes attached at the same time as the nucleophilic leaving group is split off. The intermediate dioxolanylium ion is exceedingly reactive. The chapter presents reactions that can generate the dioxolanylium and dioxanylium ring-systems selectively in carbohydrate derivatives, in the absence of a nucleophile and in the presence of a difficultly polarizable complex anion. The various rearrangement reactions such as rearrangement of acyloxonium ions in polyol systems and monosaccharides, rearrangement of esters of polyols and monosaccharides in liquid hydrogen fluoride, rearrangement of cyclitols with acetic acid-sulfuric acid, and rearrangement of saccharides with other lewis acids are studied in the chapter.

The causal boundary of space-times

Abstract: A definition of a causal boundary $$\dot V$$ is given by assigning a future and a past endpoint to any non-extensible timelike or null line. A topology and a partial ordering can be introduced on $$\bar V: = \dot V \cup V$$ . The usual conditions for the causal structure can be formulated as properties of $$\dot V$$ . This boundary is compared with other types of boundaries.

On the relationship between geostrophic and surface wind at sea

Abstract: The ratio between observed surface and geostrophic wind speed has been investigated from observations at the German Bight, taking geostrophic wind and the air-sea temperature difference as parameters. The ratio decreases with increasing geostrophic wind and increasing stability. While stability is an important parameter for light to moderate winds, variation of the ratio with geostrophic wind speed cannot be neglected, taking the full range of geostrophic wind speeds into consideration. From the Navier-Stokes equations, such a variation is to be expected. For light winds, the (local) surface wind may exceed the (mesoscale) geostrophic wind. Both effects together can be described approximately by a linear relation between the surface wind and geostrophic wind, with a slope of 0.56 and a constant term b>0 varying with stability. The residual error was 2 m/s. Variation with latitude is inferred from the Navier-Stokes equations.

On the superpropagator of fields with exponential coupling

Abstract: We define the vacuum expectation value of the time-ordered product of two exponentials of free fields as a distribution using minimal singularity as a criterion. The implication of this definition for an exponentially self-coupled scalar field is studied in second order of a perturbation expansion.

Alpha-1-antitrypsin: physiology, genetics and pathology.

Abstract: Alpha1-antitrypsin (α1) is a glycoprotein in human serum that inhibits the enzymatic activity of trypsin and other proteolytic enzymes. Its concentration in normal serum is 200–250 mg/100 ml. In certain physiological and pathological situations, such as pregnancy, under contraceptive medication and during inflammation, the level of α1-at is elevated. The physiological role of α1 is not known, but the interaction with proteolytic enzymes from white blood cells is probably important. Electrophoretic techniques distinguish several phenotypes, which can be explained by the existence of several codominant alleles at one locus (probably the structural locus). Two alleles PiZ and PiS cause low concentrations of α1-at in serum: the approximate concentrations of α1-at for the different phenotypes are Z/Z 10%, M/Z 50–60%, S/S 60%, M/S 80%, where the level of 212 mg/100 ml found in the M/M phenotype is taken as 100%; thus the effect of these alleles on the α1-at concentration is additive. Homozygosity for the PiZ allele is strongly associated with chronic obstructive lung disease and there is also an association of COPD and heterozygosity for the PiZ or PiS or both, but to a lesser degree.

Umlagerungen bei der durch Lithiumbutyl initiierten Polyreaktion der Diene Isopren und Butadien

Abstract: Bei der Reaktion von Lithiumbutyl mit Isopren in Diathylather entstehen Lithiumnonenyle, die bei der Zersetzung mit Wasser 36% 2-Methylocten-(1) und die cis-trans-Isomeren des 3-Methyl-octens-(2) im Verhaltnis 63:1 ergeben. Nach Entfernung des Diathylathers vom Lithiumnonenyl durch Abkondensation nach wiederholterZugabe von n-Heptan werden die Kohlenwasserstoffe im Verhaltnis 26 : 74 gefunden, wahrend nach erneuter Zugabe von Diathylather wieder das Verhaltnis 36 : 64 auftritt. Das Verhaltnis der verschiedenen isomeren Lithiumnonenyle ist vom Losungsmittel abhangig. Die Isomeren lagern sich reversibel um; auch in Diathylather findet in erheblichem Umfange 1.4-Addition von Isopren an Lithiumbutyl statt. Wahrend bei −10°C fur die Polyreaktion des Isoprens mit Lithiumbutyl als Initiator die Geschwindigkeitskonstanten gefunden werden, betragen die entsprechenden Werte fur die Polyreaktion des Butadiens Das kinetisch erfasbare Assoziationsverhalten von Lithiumpolyisoprenyl wird durch beschrieben, wahrend Lithiumpolybutadienyl durch beschrieben wird. Die Vermutung, das primar immer 1.4-Verknupfung erfolgt, deren Produkt dann unter der Wirkung des Initiators isomerisiert, wird gestutzt durch die Zunahme der 1.4-cis-Struktur mit fallender Initiatorkonzentration: Text Table Text. Initiatorkonz. 1.4-cis-Struktur Mol/l Isopren Butadien 3·10−2 80% 35% 5·10−5 95% 70% <10−5 98% – Die bewiesene Umlagerung lost den Widerspruch zwischen postuliertem Primarschritt und gefundenen Produktstrukturen. Die Initiatorabhangigkeit der Stereoselektivitat wird mit Hilfe einer Geschwindigkeitskonstanten ki, cis = 105 ± 10 I/Mol·sec der Isomerisierungsreaktion simuliert. The reaction of lithiumbutyl with isoprene in diethylether produces lithiumnonenyls, which yield after decomposition with water 36% 2-methyloctene-(l) and the cis-trans-isomers of 3-methyloctene-(2) in the ratio 63:1. After removal of diethylether from the lithiumnonenyl by decondensation by means of vacuum with repeated addition of n-heptane, the hydrocarbons appear in the ratio 26:74. After adding a further amount of diethylether the initial ratio of 36:64 is obtained again. The lithiumnonenyls are therefore rearranged reversibly, depending on the solvent; also in diethylether a 1.4-addition of isoprene to lithiumbutyl takes place in a considerable extent. The rate constants of the polymerization of isoprene with lithiumbutyl as initiator at atemperature of −10°C were found to be The corresponding values for the polymerization of butadiene amount to The association of lithiumpolyisoprenyl attained kinetically is described by while lithiumpolybutadienyl is described by The supposition that primarily always a 1.4-addition takes place, followed by an isomerisation, is confirmed by the increase of 1 .4 4 structures with decreasing concentration of the initiator. Text Table Text. Concn. of initiator 1.4-cis-structure mole/l. Isoprene Butadiene 3·10−2 80% 35% 5·10−5 95% 70% <10−5 98% – The proved rearrangement solves the contradiction between postulated primary step and the determined structures of the products. The dependence of the stereoselectivity on the concentration of the initiator is simulated by means of a rate constant of isomerization ki, cis = 105 ± 10 l./mole.sec.

Nahrungs-Eisenresorption aus Schweine-Fleisch, -Leber und -Hämoglobin bei Menschen mit normalen und erschöpften Eisenreserven

Abstract: Radiochemisch reines59Fe wurde ca. 72 kg schweren Schweinen einen Monat vor der Schlachtung intravenos injiziert. An Personen mitnormalen underschopften Eisenreserven wurde die59Fe-Resorption aus jeweils 5 mg59Fe enthaltenden Fleisch- bzw. Hackfleischmengen (∼ 200 g), Leber-Mengen (∼ 25 g) und Hamoglobin (1,44 g) ermittelt. Die59Fe-Resorption wurde aus der mit einem 4π-Grosraum-Radioaktivitatsdetektor mit flussigem organischem Szintillator gemessenen59Fe-Gesamtkorperretention errechnet.

Determination of the ellipticity of light and of optical constants by use of two reflection polarizers.

Abstract: A method is described which allows the determination of the ellipticity of light (i.e., the degree of polarization as well as the phase difference of the mutually perpendicular electric field components) by intensity measurements behind two reflection polarizers. The method yields simultaneously the complex reflection coefficient of the first polarizer and its optical constants if it consists of only one mirror. The method is especially suited for the extreme ultraviolet where neither transmission polarizers nor simple phase shifters are available.

Über selektive katalytische Oxydationen, XXVIII. Katalytische Oxydation der 1.6‐Anhydro‐α‐D‐galaktofuranose. Darstellung der 1.6‐Anhydro‐β‐L‐altrofuranose

Abstract: 1.6-Anhydro-β-D-glucofuranose (1) und 1.6-Anhydro-α-D-galaktofuranose (3) wurden den Bedingungen der katalytischen Oxydation unterworfen, wobei nur 3 an der aquatorialen 5-Hydroxylgruppe zur 1.6-Anhydro-β-L-arabino-hexofuranos-5-ulose (4) oxydiert wurde. Die Ketose 4 konnte stereoselektiv mit Pd-C/H2 zur 1.6-Anhydro-β-L-altrofuranose (2) reduziert werden. Die Anhydroverbindung 2 wurde zu 1.6% im sauren Medium im Gleichgewicht der Altrose nachgewiesen. Die optische Drehung von 2 steht in Ubereinstimmung mit einem berechneten Wert.

Electron microscopical evidence for innervation of chief cells in human parathyroid gland.

Abstract: Erstmalig werden ultrastrukturell neuroepitheliale Synapsen vegetativer Nerven an den Hauptzellen von Nebenschilddrusen (Mensch) nachgewiesen. Eine nervose Beeinflussung der Parathormonsynthese und -sekretion ist daher moglich.