Showing papers by "University of Cologne published in 1976"

General Relativity with Spin and Torsion: Foundations and Prospects

Abstract: A generalization of Einstein's gravitational theory is discussed in which the spin of matter as well as its mass plays a dynamical role. The spin of matter couples to a non-Riemannian structure in space-time, Cartan's torsion tensor. The theory which emerges from taking this coupling into account, the ${U}_{4}$ theory of gravitation, predicts, in addition to the usual infinite-range gravitational interaction medicated by the metric field, a new, very weak, spin contact interaction of gravitational origin. We summarize here all the available theoretical evidence that argues for admitting spin and torsion into a relativistic gravitational theory. Not least among this evidence is the demonstration that the ${U}_{4}$ theory arises as a local gauge theory for the Poincar\'e group in space-time. The deviations of the ${U}_{4}$ theory from standard general relativity are estimated, and the prospects for further theoretical development are assessed.

Fractional Programming. II, On Dinkelbach's Algorithm

Abstract: Dinkelbach's algorithm [Dinkelbach, W. 1967. On nonlinear fractional programming. Management Sci.13 492--498.] solving the parametric equivalent of a fractional program is investigated. It is shown that the algorithm converges superlinearly and often locally quadratically. A priori and a posteriori error estimates are derived. Using those estimates and duality as introduced in Part I, a revised version of the algorithm is proposed. In addition, a similar algorithm is presented where, in contrast to Dinkelbach's procedure, the rate of convergence is still controllable. Error estimates are derived also for this algorithm.

IS-elements in microorganisms.

Abstract: The bacterial chromosome, while evolving by point mutations in its DNA, is thought to be rather stable with regard to its gross organization. For example, even though the DNAs of Salmonella and Escherichia cross-hybridize only weakly due to divergent sequence evolution (Demerec and New, 1965; Brenner et al., 1969), the genetic maps of the two bacteria are rather similar with respect to the order of functions (Sanderson and Demerec, 1965).

Fractional Programming. I, Duality

Abstract: This paper, which is presented in two parts, is a contribution to the theory of fractional programming, i.e., maximization of quotients subject to constraints. In Part I a duality theory for linear and concave-convex fractional programs is developed and related to recent results by Bector, Craven-Mond, Jagannathan, Sharma-Swarup, et al. Basic duality theorems of linear, quadratic and convex programming are extended. In Part II Dinkelbach's algorithm solving fractional programs is considered. The rate of convergence as well as a priori and a posteriori error estimates are determined. In view of these results the stopping rule of the algorithm is changed. Also the starting rule is modified using duality as introduced in Part I. Furthermore a second algorithm is proposed. In contrast to Dinkelbach's procedure the rate of convergence is still controllable. Error estimates are obtained too.

Study of the frequency distribution of the fluorescent light induced by monochromatic radiation

Abstract: The frequency distribution of the fluorescent light induced by monochromatic dye laser radiation was investigated. To exclude the influence of the Doppler width a strongly collimated atomic beam was used. The spectrum was measured by means of a piezoelectrically tunable spherical Fabry Perot. The interaction region between the laser light and the atomic beam was placed into the center of the interferometer. Thus the observed fluorescence spectrum was considerably more intense than in the case where the interferometer is used separately from the beam. The fluorescence spectrum was observed for different directions of polarization of the incident laser beam. In the case of weak excitation the spectrum consists of a sharp component essentially due to elastically scattered light. At high intensities a structure of three components is observed which is in agreement with theoretical predictions when circularly polarized light is used for excitation.

Idiotypic analysis of lymphocytes in vitro. I. Specificity and heterogeneity of B and T lymphocytes reactive with anti-idiotypic antibody.

Abstract: Guinea pig anti-idiotypic antibodies (anti-Id) of the IgG1 class, directed to an A/J antibody to Group A streptococcal carbohydrate (A-CHO), or directed to a BALB/c myeloma protein that binds the same antigen, stimulate B-precursor cells as well as T-helper cells when injected into mice of the appropriate strain. The strain-specific induction of both precursor and helper activity was detected by in vitro secondary responses of primed spleen cells to A-CHO or to 2,4,6-trinitrophenyl (TNP) upon challenge with Group A streptococcal vaccine (Strep.A) or with TNP-Strep.A, respectively. B- and T-cell populations primed with anti-Id were uniform with respect to the binding of antigen and of anti-Id. This was in contrast to cells primed with Strep.A, which were heterogenous. Taken together, B and T cells that possess the same antigen-binding specificity share idiotypic determinants, reveal the same idiotypic polymorphism, and may display similar degrees of heterogeneity with respect to the binding of antigen and anti-Id. Since the anti-Id used in this study detect Id determinants associated with the heavy chain of the variable region of mouse antibodies, the data suggest that this region of the immunoglobulin molecule is shared between T- and B-cell antigen receptors.

A survey of translocation in laminariales (Phaeophyceae)

Abstract: A survey of translocation of photoassimilates in 13 genera of Laminariales is presented. All showed long-distance transport of 14C-labeled products from mature source tissue to meristematic sinks (haptera and intercalary growing regions). In plants with several laminae forming one frond, older laminae may provide assimilates for the growth of younger ones, and in Macrocystis spp., where fronds of different ages and developmental stage arise from a common holdfast, mature fronds initiate and support new fronds. Translocation velocities vary from species to species but are in the range of 55 to 570 mm/h. The results strongly support the hypothesis that Laminariales in general have an effective translocation system, on which their thallus growth depends.

Tissue Distribution of Ia Antigens and their Expression on Lymphocyte Subpopulations

Abstract: The major histocompatibility {H-2) complex in the IXth linkage group on the 17th mouse chromosome consists of K, I, S and D regions with K and D coding for the classical H-2 transplantation antigens and S controlling soluble serum proteins. The central segment of the H-2 complex, the / (immune response) region is of particular interest because during the last few years it has become apparent that it plays a major role in numerous immunological phenomena including genetic control of immune responsiveness, mixed lymphocyte and graft versus host reactions, graft rejection, and cellular interaction in the immune system (Shreffler & David 1975). Because adequate understanding of the nature and interrelationship of these reactions depends largely on the elucidation of the molecular entities involved, much effort has been invested into the identification of /-region gene products. These studies were considerably facilitated by the use of congenic pairs of mice, such as A.TL (X« P S^ D^ and A.TH {K' I\" 5* D^ which have identical H-2K and H-2D regions and differ only in their / and S regions. Antisera produced in these mice by reciprocal immunization with lymphoid cells permitted the detection of a group of polymorphic cell-surface structures, designated Ia antigens (immune-region-associated antigen) (David et al. 1973, Gotze et al. 1973, Hauptfeld et al. 1973, Hammerling et al. 1974, Shreffler et al. 1974). Simultaneously Sachs & Cone (1973) were able to identify Ia antigens with conventional anti-H2 sera when tested against appropriate target strains. More than 15 different Ia

Infrared Spectroscopy of Polymers

Abstract: Since 1945 inrared (IR) spectroscopy has become one of the most important methods for characterizing and studying the chemical and physical structure of compounds. Especially in the polymer field, IR spectroscopy and Raman spectroscopy have proved valuable for analytical and structural investigations. An IR spectrum of a polymer sample provides the following qualitative and quantitative information about the chemical and physical structure of the polymer under consideration: Chemical nature of the polymer: type and degree of branching, nature of end groups, impurities, etc. Steric order: cis-trans isomerism, stereoregularity, etc. Conformational order: physical arrangement of a polymer chain, planar zigzag conformation, helix conformation, etc. Crystallinity: number of chains per unit cell, intermolecular forces, etc.

Fine structure of baroreceptor terminals in the carotid sinus of guinea pigs and mice

Abstract: A light and electron microscopic study was undertaken on the baroreceptor axon terminals in the carotid sinus of guinea pigs and mice, using serial semithin and thin sections. Together with their enveloping Schwann cells, numerous lanceolate axon terminals are organized into a well-defined discoid end organ, referred to as the ‘baroreceptor unit’. Baroreceptor units measure 100 to 150 μm in diameter and are arranged in a hexagonal pattern. These end organs represent free branched lanceolate mechanoreceptors of complex type (Andres and von During, 1973) which belong to the main group of stretch receptors. In the guinea pig the lanceolate terminals enter the media and approach the innermost layers near the intima. In the mouse the terminals are seen to spread in the adventitia and along the medio-adventitial border. Only a few of them penetrate the external elastic layer. Species differences concerning the localization and extent of these visceral mechanoreceptors are discussed, as well as the modified architecture of the sinus wall in the receptor area (‘elastic segment’). Lanceolate terminals form beaded varicosities which are equipped with finger-like or lamellar axoplasmic protrusions. These projections contain a well-differentiated receptor matrix. They are attached to collagen and elastic fibers. The varicosities include densely packed mitochondria, neurotubules, profiles of axoplasmic reticulum, clear and granular vesicles, and striking accumulations of glycogen particles, lamellated bodies and lysosomes. Four types of varicosities are discerned according to their main axoplasmic components. Various types of these varicosities occur within an individual lanceolate terminal. The adrenergic innervation of the carotid sinus was studied by fluorescence histochemistry. In guinea pigs a multilayered wide-meshed plexus of fluorescent fibers occurs in the adventitia where it is closely related to baroreceptor stem fibers. However, adrenergic axons do not enter the media. In mice fluorescent fibers are extremely rare in the adventitia of the carotid sinus.

Systemic use of a new retinoid with and without local dithranol treatment in generalized psoriasis.

Abstract: giving little trouble undl 3 years ago. It then became more active, new lesions appeared, especially on her scalp, and the older ones enlarged. Topical steroids, combined with the use of Uvistat before light exposure, did not help her at all. She was started on chloroquin sulphate 200 mg twice daily, with initial relief. This had to be stopped after 5 weeks because of nausea, retching, photophobia, and weakness in the legs. After the chloroquine was stopped, she flared severely over the face and neck, and when seen in July she was both unsightly and depressed. She was given beta-carotene 50 mg three times daily, and had complete comfort within 2 weeks. This was maintained and all the lesions have regressed satisfactorily. She has been able to discondnue local steroids, and has had no sideeffects from the beta-carotene, which was stopped after 2 months.

The effects of “Cell age” upon the lethal effects of physical and chemical mutagens in the yeast, Saccharomyces cerevisiae

Abstract: Summary Yeast cultures progressing from the exponential to the stationary phase of growth showed changes in cell sensitivity to physical agents such as UV light, heat shock at 52° C and the chemical mutagens ethyl methane sulphonate, nitrous acid and mitomycin C. Exponential phase cells showed maximum resistance to UV light and minimum resistance to heat shock and the three chemicals. The increased resistance of exponential phase cells to UV light was shown to be dependent upon the functional integrity of the RAD 50 gene. Treatment of growing yeast cultures with radioactively labelled ethyl methane sulphonate indicated the preferential uptake of radioactivity during the sensitive exponential stage of growth. The results indicated that the differential uptake of the chemical mutagens was responsible for at least a fraction of the variations in cell sensitivity observed in yeast cultures at different phases of growth.

Idiotypic analysis of lymphocytes in vitro. II. Genetic control of T-helper cell responsiveness to anti-idiotypic antibody.

Abstract: When the IgG1 fraction of anti-idiotypic antibodies raised in guinea pigs is injected into mice, sensitization of idiotypic T and B lymphocytes occurs (1-3). In the present study we analyze the genetic requirements for T-helper cell sensitization by anti-idiotypic antibody. This was done by measuring, in a suitable panel of mouse strains, helper cell responsiveness to two anti-idiotypic reagents which recognize distinct, strain-specific idiotypes, namely the A5A and the S117 marker. Whenever helper cell sensitization by anti-idiotypic antibody was successful, helper function could be specifically inhibited by the same and only the same anti-idiotype. This indicates that helper cells induced by anti-idiotypic antibody express idiotypic determinants on their receptors for antigen. Helper cell sensitization by anti-idiotypic antibody was found in all strains expressing the corresponding or a cross-reactive idiotype at the immunoglobulin level. Idiotype-negative strains were always unresponsive to anti-idiotypic stimulation. In addition, responsiveness did not depend on the H-2 haplotype. Since the A5A and the S117 idiotype are markers for V genes in the heavy-chain linkage group, the present results support the view that the same genes in the Ig-1 complex code for variable portions of immunoglobulins and T-helper cell receptors.

Short-term and circadian rhythms in the behaviour of the vole, Microtus agrestis (L.).

Abstract: The activity behaviour of the vole, Microtus agrestis, has been recorded in order to investigate the relationship between short-term rhythm and circadian rhythm. A simple device was developed, allowing separate monitoring of the time spent in or outside the nest, wheel-running, eating and drinking. Under natural light conditions during summer, a distinct differentiation between a short term rhythm of eating and drinking during the day-time and a circadian rhythm of wheel-running during the night was observed. The short-term rhythm depends closely on metabolic demands (hunger, thirst, excretion). Control of these demands by an endogenous oscillation could not be substantiated. The circadian rhythm of wheel-running activity is, however, controlled by an endogenous oscillation, synchronized by light conditions. It is subjected to seasonal variations. a) The threshold of light intensity below which wheel-running occurs is lowest during summer ( 5 lx). b) Wheel-running is controlled by a circadian oscillation during summer only whereas it is an integrated part of the short-term rhythm during spring and autumn (experiments during the winter have not yet been performed). Experiments gave evidence that the properties of the cage can deeply influence the amount and pattern of wheel-running activity. It is concluded that wheel-running reflects a certain level of excitation, which may be caused by different behavioural intentions. The seasonal changes of the control of wheel-running activity are discussed with respect to this assumption. The relevancy of locomotor activity patterns as usually recorded in the laboratory to reveal the physiological and ecological significance of endogenously controlled behavioural patterns is discussed.

Intracellular forms of adenovirus DNA: integrated form of adenovirus DNA appears early in productive infection.

Abstract: In KB cells productively infected with adenovirus type 2, alkali-stable greater than 100S and 40-100S viral DNAs are synthesized starting 2-4 hr postinfection, i.e., before unit length (34 S) viral DNA is made. The amount of greater than 100S and 40-100S viral DNA increases when 34S viral DNA synthesis begins, and at 16-18 hr postinfection, the 40-100S viral DNA represents 5-20% of the total intracellular viral DNA. The 40-100S viral DNA is synthesized throughout infection. Part of the 40-100S DNA synthesized 5-8 hr postinfection has a density in alkaline CsCl gradients intermediate between those of viral and cellular DNAs. This finding indicates that newly synthesized viral DNA is covalently linked to cellular DNA. Viral sequences can be excised from the cellular DNA of infected cells with the EcoRI restriction endonuclease. Fragments of viral DNA are detected in polyacrylamide-agarose gels by DNA-DNA hybridization, and these fragments correspond in size to most of the known EcoRI fragments of adenovirus 2 DNA. Viral DNA sequences in size-classes between the EcoRI-A and -C fragments are also found and probably represent viral DNA linked to cellular sequences.

Morphology and histochemistry of the adrenal medulla. I. Various types of primary catecholamine-storing cells in the mouse adrenal medulla.

Abstract: Semithin sections (Araldite) of mouse adreno-medullary tissue were examined in the light microscope after perfusion fixation with glutaraldehyde, glutaraldehyde/formaldehyde or after freeze-drying followed by a treatment with hot formaldehyde gas. The following methods were employed: (i) aldehyde-induced fluorescence of catecholamines, (ii) Schmorl's ferric ferricyanide reaction, (iii) argentaffin reaction, and (iiii) staining with alkaline lead citrate followed by Timm's silver sulphide reaction. The correspondence of results obtained by the various methods was proven in consecutive sections or by successively applying different methods to identical sections.

Density matrix of quantum fluids

Abstract: An elaborate cluster analysis of the single-particle occupation probability ${n}_{\stackrel{^}{q}}$ and associated one-body density matrix $n(r)$ is performed for a Fermi system described by a Jastrow wave function. A diagrammatic formalism rooted in Ursell-Mayer theory facilitates the analysis. It is conjectured, and demonstrated to convincingly high cluster order, that ${n}_{\stackrel{^}{q}}$ may be written as $n[N(q)+{N}_{1}(q)]$, where $n$ is a strength factor independent of wave number $q$ and the quantities $N(q)$ and ${N}_{1}(q)$ may be expressed as series of irreducible cluster contributions. The strength factor $n$ has the form $n={e}^{Q}$, where $Q$ may also be expressed as a series of irreducible cluster contributions. Massive partial summations on the latter series yield a compact expression for $Q$ in terms of the spatial distribution functions corresponding to the Jastrow wave function. Working with the Fourier inverse of ${n}_{\stackrel{^}{q}}$, it is further demonstrated that $n(r)$ may be cast in the form $\ensuremath{\rho}n[{N}_{1}(r)+{N}_{2}(r)]\mathrm{exp}\mathcal{Q}(r)$, where $\ensuremath{\rho}$ is the particle density and the functions ${N}_{1}(r)$, ${N}_{2}(r)$, and $\mathcal{Q}(r)$ are all given by irreducible cluster series. Massive partial summations are executed in the $\mathcal{Q}(r)$ series to achieve a compact expression of this quantity in terms of the aforementioned spatial distribution functions. One has $\mathcal{Q}(0)=Q$. The leading diagrams necessary for a quantitative evaluation of the momentum distribution of liquid $^{3}\mathrm{He}$ and nuclear matter are displayed. Specialization to infinite degeneracy of the single-particle levels, while shrinking the Fermi wave number to zero (Bose limit), allows liquid $^{4}\mathrm{He}$ to be treated as well. In this limit off-diagonal long-range order appears, the condensate fraction ${\ensuremath{\rho}}^{\ensuremath{-}1}n(\ensuremath{\infty})={n}_{c}$ being just the strength factor $n$. It may also be shown (under certain reasonable assumptions) that the customary ${r}^{\ensuremath{-}2}$ long-range behavior of the two-body correlations implies a singular behavior ${n}_{q}={n}_{c}(\frac{\mathrm{mc}}{2\ensuremath{\hbar}}){q}^{\ensuremath{-}1}$ of the Bose momentum distribution for small $q$.

On the existence of surfaces with prescribed mean curvature and boundary

Abstract: (Subscripts denote differentiation, "" is the euclidean inner product and " x " the vector cross product on/R3) Under the conformality condition (03) Eq (04) expresses the fact that x has mean curvature H(x(u, v)) in x(u, v) whenever (u, v) is a regular point of the surface (For the singular points see Section 65) We shall say that x solves the Plateau problem for H and F in S, if x satisfies the above four conditions, and x solves the Dirichlet problem for H and y in S, if x satisfies (01), (04) and the Dirichlet boundary condition corresponding to a given boundary mapping y : c3B ~]R 3

Antimicrobial Susceptibility of Propionibacterium acnes and Related Microbial Species

Abstract: The minimal inhibitory concentrations of 32 antimicrobial agents were established for 73 strains of Propionibacterium acnes and four related species (P. granulosum, P. avidum, Corynebacterium minutissimum, and C. parvum). Most strains showed good susceptibility to those agents usually considered active against gram-positive organisms. With the exception of C. minutissimum, the strains tested revealed more or less identical susceptibility ranges. The lowest minimal inhibitory concentrations were observed with benzylpenicillin, ampicillin, cephalothin, rifampin, erythromycin, clindamycin, and minocycline. C. minutissimum was more susceptible to gentamicin, sisomicin, tobramycin, and fusidic acid but more resistant to most other drugs than were the other species examined.

Nutritive and non-nutritive blood flow in canine skeletal muscle after partial microembolization.

Abstract: Partial microembolization of the previously dilated gastrocnemius muscle of the dog was performed by intra-arterial injection of latex microspheres (max. diameter 50 mum). No particles larger than 10 mum were recovered from the venous blood. Blood to tissue clearance of 4-amino-antipyrine was found to decrease after microembolization, and capillary transport coefficients were disproportionately lowered in comparison with the observed decrease of total blood flow. Venous oxygen saturation increased despite decreasing total blood flow in the working muscle after microembolization. The data indicate a shift of blood flow from nutritive to functionally non-nutritive channels.

The influence of the prolactin-inhibitor bromocriptin (CB 154) on human luteal function in vivo

Abstract: Five volunteers with normal ovarian cycles received oral doses of 2×2.5 mg or 3×2.5 mg bromocriptin (CB 154)/day respectively. The treatment started at the onset of menstruation and lasted one complete cycle. In addition to the decrease of prolactin secretion, a reduction of plasma progesterone concentrations during the corpus luteum phase was demonstrated. This fall of progesterone seemed to be preferentially due to bromocriptin-induced hypoprolactinaemia and not to direct ovarian effects of the drug.