Showing papers by "University of Freiburg published in 1980"
TL;DR: In this paper, a solution of the gauge hierarchy problem is given, without any further unnatural condition, a neutrino mass which is hierarchically small compared with the light-charged fermion masses.
988 citations
TL;DR: Aspirin can achieve a ceiling effect on TXB2 production in healthy subjects at a considerably lower dosage than currently employed regimens for antithrombotic therapy.
625 citations
TL;DR: By centrifuging total cellular DNA derived from human genital warts (condylomata acuminata) in CsCI‐ethidium bromide gradients, supercoiled DNA was isolated and it was concluded that the super coiled DNA molecules were derived from papilloma virus nucleocapsids.
Abstract: By centrifuging total cellular DNA derived from human genital warts (condylomata acuminata) in CsCl-ethidium bromide gradients, supercoiled DNA was isolated. The molecular weight of this DNA was determined by agarose gel electrophoresis and amounted to 5.1 X 10(4). This DNA isolated from an individual genital wart was annealed to fractions of aqueous supernatants of the same wart after prior centrifugation of this material in CsCl density gradients. Annealing was observed at a density of approximately 1.32 g/ml corresponding to the expected density of papilloma virus particles. Since such particles were also observed in the same preparation by electron microscopy, it was concluded that the supercoiled DNA molecules were derived from papilloma virus nucleocapsids. Positive hybridization was found with six additional preparations from individual genital warts. Therefore, it seems that the isolated DNA prevails in condylomata acuminata. The DNA is different from the other five types of human papilloma viruses described thus far in regard to its restriction endonuclease cleavage patterns. The virus analyzed is tentatively designated as human papilloma virus type 6 (HPV 6).
278 citations
TL;DR: Methods and parameters to quantify body sway as measured by a force-transducing platform determine the visual stabilization of posture and some of them seem of clinical significance not only for documentation and follow-up studies but also for differential diagnosis.
Abstract: Methods and parameters are described to quantify body sway as measured by a force-transducing platform. Analogue data representing the coordinates of the body's center of force (COF) are fed into a digital computer. Th following parameters are then calculated and tested for their diagnostic significance: sway path (SP), mean amplitude of sway (MA), mean sway frequency (MF), their lateral and sagittal components, and the quotients sagittal/lateral of these as well as the sway area (SA) circumscribed by the COF. Quotients of eyes open/eyes closed for all these parameters determine the visual stabilization of posture. Sway position and sway direction histograms allow for a more detailed analysis of MA and SP. Despite considerable inter- and intraindividual variance of these parameters (in 28 normals), some of them seem of clinical significance not only for documentation and follow-up studies but also for differential diagnosis. In patients with cerebellar lesions (n = 12), SP and MA were up to 10 times larger with a marked antero-posterior instability, MF being above normal. Patients with labyrinthine lesions (n = 10) showed significant instability only with eyes closed, MF being slightly below normal.
250 citations
TL;DR: An electronic Hamiltonian appropriate for describing core-hole processes is derived and its properties are discussed in this article, where a many-body theory is presented, and a useful linked-cluster theorem is proven.
Abstract: An electronic Hamiltonian appropriate for describing core-hole processes is derived and its properties are discussed. Based on this Hamiltonian a many-body theory is presented, and a useful linked-cluster theorem is proven. A distinction between relaxation and correlation terms can be made in each order of the perturbation expansion. Under certain well-defined conditions the core-ionization process can be visualized as a Franck-Condon transition between two multidimensional potential-energy surfaces in an abstract bosonic space. The corresponding approximation, the boson approximation, is discussed and applied to the water molecule.
235 citations
TL;DR: In this paper, the packing of long-chain diacetylene monocarboxylic acid in the form of Langmuir-Blodgett (LB) multilayers was investigated using electron diffraction and small angle X-ray techniques.
225 citations
TL;DR: The nucleotide sequence of ribosomal DNA coding for 16S rRNA from Zea mays chloroplast has been determined and a comparison with the 16s rRNA sequence from Escherichia coli reveals strong homology and demonstrates the prokaryotic nature ofchloroplast ribosomes from a higher plant.
Abstract: The nucleotide sequence of ribosomal DNA coding for 16S rRNA from Zea mays chloroplast has been determined. A comparison with the 16S rRNA sequence from Escherichia coli reveals strong homology and thereby demonstrates the prokaryotic nature of chloroplast ribosomes from a higher plant.
216 citations
TL;DR: In this article, the photochemical and thermal cis-trans isomerization of azo chromophores which were either dissolved, a pendant group or part of a crosslink in rubbery poly(ethyl acrylate) networks has been investigated.
216 citations
TL;DR: It is concluded that the oscillations around 1 Hz are due to the long latency and high threshold of vestibularly induced leg muscle discharges arriving in the counterbalancing phase of the trunk, which causes an overshoot in body sway.
Abstract: After minimizing proprioceptive input from the legs by ischemia without degradation of muscle force and excluding visual stabilization by eye closure, a characteristic anterior-posterior postural sway around 1 Hz was observed in three normal subjects. This is similar to the instability seen in two tabes dorsalis patients. From the spectral analysis of head and hip movements, displacements of the center of force and of ankle angle as well as from EMG recordings of the anterior tibial and gastrocnemius muscle it is concluded that the oscillations around 1 Hz are due to the long latency and high threshold of vestibularly induced leg muscle discharges (200–300 ms) arriving in the counterbalancing phase of the trunk, which causes an overshoot in body sway.
190 citations
176 citations
TL;DR: Chlorophyll a formation seems to be a light-dependent step which is required for the stabilization of the LHCP and might be explained by the deficiency of chlorophyll in the red light-treated plants.
Abstract: The effect of light on the biosynthesis of the light-harvesting chlorophyll a/b protein (LHCP) is investigated in wild-type barley (Hordeum vulgare L.) and in the chlorophyll b-less mutant chlorina f2. In dark-grown plants a short red light pulse triggers the appearance of mRNA activity for the LHCP. While the accumulation of this mRNA is controlled by phytochrome (Apel (1979) Eur. J. Biochem. 97, 183–188), the red light treatment is not sufficient to induce the appearance of the LHCP within the membrane. Thus, at least one of the subsequent steps in the biosynthetic pathway leading to the assembly of the LHCP is controlled by light. The red light-induced mRNA is taken up into the polysomes during the subsequent dark period and is translated in vitro in a cell-free protein synthesizing system. However, an accumulation of the freshly synthesized polypeptide within the plant is not observed. The apparent instability of the polypeptide might be explained by the deficiency of chlorophyll in the red light-treated plants. In the chlorophyll b-less barley mutant chlorina f2 an accumulation of the freshly synthesized apoprotein of the LHCP can be observed in the light. Thus, chlorophyll a formation seems to be a light-dependent step which is required for the stabilization of the LHCP.
TL;DR: D. pumilio is the first frog known to feed its free-living larvae, and not only involves egg attendance and tadpole transport, but also tadpole attendance and feeding.
Abstract: Brood care in Dendrobates pumilio not only involves egg attendance and tadpole transport, but also tadpole attendance and feeding. Each tadpole is carried by the attending female to a water-filled bromelial leaf axil and regularly fed on unfertilized eggs. The tadpole responds to an approaching adult with a specialized, conspicuous behavior signalling its presence. Male-male competition includes fighting, egg eating, and male tadpole transport. D. pumilio is the first frog known to feed its free-living larvae.
TL;DR: Action spectra for the inhibition by continuous (24-hour) irradiation of hypocotyl growth in 54-hour-old Sinapis alba L. seedlings show that the blue, red, and far-red (716 nm) wavebands are most inhibitory for dark-grown plants with high phytochrome content, whereas hypocotel growth in dark- grown plants with a low phy tochrome content are only slightly inhibited by blue and far -red radiation
Abstract: Action spectra for the inhibition by continuous (24-hour) irradiation of hypocotyl growth in 54-hour-old Sinapis alba L. seedlings were measured using seedlings which had had four different pretreatments. These seedlings were either ( a ) dark-grown with a high total phytochrome level, ( b ) dark-grown with a low total phytochrome level, ( c ) light-grown with chlorophyll, or ( d ) light-grown with no chlorophyll [treated with 4-chloro-5-(methylamino)-2-(α,α,α-trifluoro- m -tolyl)-3(2H) -pyridazinone (San 9789)]. The resulting action spectra show that the blue, red, and far-red (716 nm) wavebands are most inhibitory for dark-grown plants with high phytochrome content, whereas hypocotyl growth in dark-grown plants with a low phytochrome content are only slightly inhibited by blue and far-red radiation. In light-grown plants, the effectiveness of blue and far-red light almost disappears. The position of red light effectiveness in chlorophyll-containing plants is shifted to lower wavelengths compared with those containing no chlorophyll.
TL;DR: Dorsal, a new maternal-effect mutant, seems to exert a similar influence on the dorso-ventral coordinate for patterning in early embryonic pattern formation, which is temperature sensitive and is reported on here.
Abstract: Mutations altering the spatial pattern of embryonic primordia are valuable tools for studying the earliest steps of embryonic pattern formation. As the spatial organisation of the egg cell arises during oogenesis, such mutants are likely to affect the embryo via the maternal genome (maternal effect). In Drosophila, most maternal-effect mutants studied so far lead to early developmental arrest. A few others yield pattern defects apparently linked to local failure of blastodermal cellularisation rather than to abnormal arrangement of primordia or ooplasmic determinants1,2. A small number of mutants, however, are known in which the embryonic fate map is affected, for example, bicaudal3,4, which profoundly alters the antero-posterior pattern of embryonic organisation. The bicaudal phenotypes suggest that the mutation causes a perturbation of a morphogen gradient that defines the antero-posterior coordinate in early embryonic pattern formation5,6. A new maternal-effect mutant, dorsal, seems to exert a similar influence on the dorso-ventral coordinate for patterning6. Dorsal (dl) has both a recessive and a dominant maternal-effect phenotype. The dl recessive phenotype is marked by an apparently complete lack of dorso-ventral polarity from early embryogenesis onward6. The dl dominant (dlD) phenotype, which we report on here, is temperature sensitive: at 22 °C, dl/+females lay eggs which develop normally while eggs produced at high temperature (29 °C) yield abnormal larvae which fail to hatch. These mutant dlD larvae vary in phenotype but nearly always lack muscles and frequently part of the ventral hypoderm. They are defective in structures that arise from the ventral region of the blastoderm in normal embryogenesis6,7 (Fig. 1).
TL;DR: Results indicate that the STS locus is at Xp223, based on cytogenetic evidence obtained with an elongation technique, and it is concluded that ichthyosis in a male child and his mother is caused by an unbalanced X-Y translocation.
Abstract: A male child and his mother who are nullisomic and monosomic, respectively, for the distal portion of Xp because of an unbalanced X-Y translocation were tested for steroid sulfatase activity after clinical examination had yielded evidence for ichthyosis in the boy. Deficiency of steroid sulfatase was found in the male patient, while in his mother enzyme levels were in the heterozygous range. These results, based on cytogenetic evidence obtained with an elongation technique, indicate that the STS locus is at Xp223.
TL;DR: For two-dimensional nonlinear σ-models on riemannian symmetric spaces G/H, there exists a natural formulation in terms of a single gauge-invariant G-valued field as discussed by the authors.
TL;DR: Hydroxylations at positions 1 and 6 of the steroid skeleton are regularly encountered, as well as the occurrence of 3β-hydroxy- Δ 5 compounds and of bile acids of the 5α series, suggest that fetal bile acid synthesis differs markedly from that of the adult.
TL;DR: The active ATP-dependent uptake of Ca(2+) into a plasma membrane-enriched microsomal fraction from plants is stimulated by the addition of plant as well as bovine brain calmodulin and this stimulation occurs only when the microsomes are prepared in the presence of EDTA.
Abstract: The active ATP-dependent uptake of Ca2+ into a plasma membrane-enriched microsomal fraction from plants is stimulated by the addition of plant as well as bovine brain calmodulin. This stimulation occurs only when the microsomes are prepared in the presence of EDTA. Plant calmodulin also activates the bovine brain 3′,5′-cyclic-nucleotide phosphodiesterase (EC 3.1.4.17). Mitochondrial Ca2+ accumulation is not affected by calmodulin. The calmodulin-mediated activation of microsomal Ca2+ uptake is abolished by the antipsychotic drug fluphenazine, whereas the calmodulin-independent Ca2+ uptake is only slightly decreased.
TL;DR: In this article, it was shown that a certain four-dimensional field theory has powerful structures in common with the two-dimensional 0(1, 3) non-linear σ-model.
Abstract: We show that a certain four-dimensional field theory has powerful structures in common with the two-dimensional 0(1, 3) non-linear σ-model.
TL;DR: In this paper, the spectral function of ionization is discussed for the whole energy range, and it is found that different energy regions are likely to exhibit different types of many-body effects.
Abstract: The spectral function of ionization is discussed for the whole energy range. It is found that different energy regions are likely to exhibit different types of many-body effects. For the ionization out of an outer valence orbital most of the intensity appears in one main line. The many-body effects explain the additional satellite lines and, in addition, can lead to an ordering of main lines which is different from the ordering determined from one-particle calculations. For the ionization out of an inner valence orbital the intensity may be distributed over several lines and in many cases it is not possible to identify any of these lines as the main line representing the orbital. Such a breakdown of the quasiparticle picture of ionization is stressed to be a common phenomenon. Ionization of core orbitals can usually be viewed within a quasiparticle picture, i.e., the process leads to a main line accompanied by satellite lines. In cases, however, where the creation of the core hole leads to a strong charge transfer, the shake-up energies can become small or even negative and the quasiparticle picture may break down. The origin of the above effects is discussed and typical examples are presented.
TL;DR: Enzyme preparations from flowers of defined genotypes of Matthiola incana contain two dif ferent hydroxylases for hydroxolation of naringenin in the 3-and 3′-position, respectively.
Abstract: Abstract Enzyme preparations from flowers of defined genotypes of Matthiola incana contain two dif ferent hydroxylases for hydroxylation of naringenin in the 3-and 3′-position, respectively. The 3-hydroxylase is a soluble enzyme and requires as cofactors 2-oxoglutarate, Fe2+ and ascorbate. Besides naringenin eriodictyol is a substrate for the 3-hydroxylase. The 3′-hydroxylase is localized in the microsomal fraction and requires NADPH as cofactor. Naringenin and dihydro-kaempferol but not 4-coumarate or 4-coumaroyl-CoA are substrates for this enzyme. 3′-Hydroxylase activity is present only in genetic lines of M. incana with the wild-type allele b+.
TL;DR: Because of the structural similarity between the hopane ring system and cholesterol, a possible similarity in the function within the membrane was investigated, by inserting the glycolipid containing hopane into the cytoplasmic membrane using the monolayer technique.
TL;DR: In this paper, sufficient conditions are established when a continuous design contains maximal information for a prescribed s-dimensional parameter in a classical linear model, and the results apply in particular to a class of information functionals which covers c-, D-, A-, L-optimality.
TL;DR: Intactness and the oxidative and phosphorylative properties of the mitochondria remained unchanged during this time period and Na+ and Mg2+ do not induce Ca2+ release from mitochondria.
Abstract: Mitochondria from etiolated corn possess a much greater Ca2+ uptake capacity per mg protein than microsomes from the same source. Differences in energy requirements, sensitivity to specific inhibitors, and sedimentation properties enabled us to study both Ca2+ uptake mechanisms without mutual contamination. The microsomal Ca2+ uptake does not vary much among different plants as compared to the mitochondrial Ca2+ uptake; this is also true for different organs of the same plant. Mitochondrial Ca2+ uptake is more dependent on the age of the seedlings than microsomal uptake, because of changes in active Ca2+ uptake activity rather than of changes in efflux. Intactness and the oxidative and phosphorylative properties of the mitochondria remained unchanged during this time period. Na+ and Mg2+ do not induce Ca2+ release from mitochondria.
TL;DR: The existence of a strict correlation between presence of testicular tissue and the presence of H-Y antigen in mammals and man leads to the conclusion that HY antigen is an essential differentiation factor in testicular morphogenesis as mentioned in this paper.
Abstract: The existence of a strict correlation between presence of testicular tissue and presence of H-Y antigen in mammals and man leads to the conclusion that H-Y antigen is an essential differentiation factor in testicular morphogenesis. Presence of low titers of this differentiation antigen even in fertile females indicates that its morphogenetic effect depends on a threshold. Here, studies on H-Y antigen in female individuals with various deletions of the X-chromosome are reported. It turns out that deletion of Xp results in the synthesis of reduced amounts of H-Y antigen, while deletion of Xq does not. In a fertile female with only Xp223 deleted due to an X/Y translocation, including the distal Yq, presence of a reduced H-Y titer allows for the tentative assignment of a controlling gene repressing the H-Y structural gene. From the cases studied, it follows that the H-Y structural gene is autosomal and under the control of X- and Y-linked genes. The conception emerges that interaction between X- and Y-linked genes or their products results in variation of the H-Y antigen titer. The fate of the indifferent gonadal anlage to differentiate into the male or the female direction will depend on the titer of H-Y antigen reached by the action or interaction of the controlling genes involved.
TL;DR: With several proteins shown that electrons can be transferred intramolecularly from tyrosine to electron-deficient tryptophan units, it seems likely that the electron transfer proceeds directly between the aromatic groups, while they are maintained at a distance from each other.
TL;DR: This work has analysed E. gracilis strain Z 16S–23S spacer DNA at the nucleotide level, hoping this would allow identification of tRNA genes together with the processing sites of the respective primary transcripts, to demonstrate whether such similarities are also preserved in the chloroplast rDNA spacer region, or if this region has suffered a higher genetic drift rate.
Abstract: Chloroplasts of the unicellular flagellate eukaryote Euglena gracilis contain several copies of a circular 135–140-kilobase pair DNA1 which codes for chloroplast-specific stable RNAs (16S, 23S (refs 2, 3), 5S rRNAs4 and tRNAs5) and for an unknown number of chloroplast-specific proteins. The rRNA genes are located within three tandemly repeated DNA regions of approximately 5.6 kilobase pairs each6–8 and the arrangement of the structural genes within each repeat follows the prokaryotic pattern, being 5′-16S-23S-5S-3′ (ref. 9). Total chloroplast tRNA hybridizes to fragments of rDNA9 and it was suggested that the 16S–23S spacer region contains tRNA coding sequences as is observed in Escherichia coli10,11 and in spinach chloroplast12 rDNA. We have therefore analysed E. gracilis strain Z 16S–23S spacer DNA at the nucleotide level, hoping this would allow identification of tRNA genes together with the processing sites of the respective primary transcripts. Maize chloroplast 16S rDNA shows strong sequence homology with E. coli 16S rRNA13. Sequence analysis of a total spacer in E. gracilis should demonstrate whether such similarities are also preserved in the chloroplast rDNA spacer region, or if this region has suffered a higher genetic drift rate. The latter is suggested from the 189 bases which have been sequenced from the 2.4-kilobase pair rDNA spacer from maize chloroplasts14. Flanking sequences, coding for the 3′-terminal region of 16S rRNA and for the 5′-terminal region of 23S rRNA have also been sequenced, to compare the drift rates between the spacer and its adjacent structural genes.
TL;DR: The results suggest that male gonadal differentiation is dependent on a threshold level of H-Y antigen concentration, and support the assumptions of an X-linked gene escaping inactivation and of it controlling the expression of the H-y structural gene.
Abstract: H-Y antigen was examined in six patients exhibiting the characteristic features of Turner syndrome Five of the patients were of the karyotype 45,X, and one was a mosaic 45,X/46,Xi(Xq) H-Y antigen was detected in all of them, however, compared to male controls, their antigen titer was reduced Within the intermediate range between female and male controls, considerable interindividual variation was detected among the patients which could be due at least in part to biological variation The findings permit the inference that the H-Y structural gene is not Y-linked, and support the assumptions of an X-linked gene escaping inactivation and of it controlling the expression of the H-Y structural gene It is probable that the structural gene itself is autosomal The results also suggest that male gonadal differentiation is dependent on a threshold level of H-Y antigen concentration
TL;DR: A combined grading system (grades 0-5) is suggested which combines histologic pattern and nuclear anaplasia in tumors with several structural patterns the most poorly differentiated one is evaluated.
Abstract: The histologic pattern of differentiation of prostate carcinoma and its grade of nuclear anaplasia was correlated with survival time in 197 patients with treated disease. In the histologic classification of prostatic carcinoma (Hohbach and Dhom, 1972) four patterns of growth are distinguished, which have different life expectancies. The survival probabilities of treated well and poorly differentiated adenocarcinoma do not show a significant difference when compared to age-matched male control groups. However, the survival probabilities in patients with cribriform and anaplastic carcinoma are significantly poorer. Even in metastatic carcinoma, the histologic pattern of differentiation seems to influence the survival probability. The grade of nuclear anaplasia (mild, moderate, marked) correlates well with the survival probability as well. The survival probability of patients with mild nuclear anaplasia does not differ from age-matched healthy males. Thus, a combined grading system (grades 0-5) is suggested which combines histologic pattern and nuclear anaplasia. In tumors with several structural patterns the most poorly differentiated one is evaluated. The reproducibility and validity of prognostic statements is more significant with the combined grading system than with only one single diagnostic criterion.
TL;DR: Upon exposure to the vapours of oleoresin from 8 conifers, bark beetlesIps typographus andI.
Abstract: Upon exposure to the vapours of oleoresin from 8 conifers, bark beetlesIps typographus andI. amitinus produced verbenol, a terpene alcohol, in a predictable pattern. Apparently, this pattern changed in relation to the varied enantiomeric composition of the α-pinene contained in the resin of the various coniferous species. For calibration, defined mixtures of (+)-and (−)-α-pinene were used to establish the different levels of beetle response in the production of cis-and trans-verbenol. Methodical and ecological implications of the phenomenon are discussed.