Showing papers by "Martin Luther University of Halle-Wittenberg published in 1973"
TL;DR: In this paper, the actual position of the system of liquid crystalline modifications is discussed, which is based on the relations of miscibility of the liquid crystal modifications and on their texture.
Abstract: We deal with the actual position of the system of liquid crystalline modifications. This system is based on the relations of miscibility of the liquid crystalline modifications and on their texture...
150 citations
TL;DR: The occurrence and distribution of rare amino acids in 104 species and 40 genera of the Mimosaceae have been studied from a comparative phytochemic.
32 citations
TL;DR: In this paper, it was shown that this method is not suitable for the unequivocal determination of the coordination number in tin complexes, since it is unsuitable for the analysis of stannatranes.
28 citations
TL;DR: PGF2a protected maximal 84 % of the animals for 10 min from letal ventricular fibrillations due to CaCl2, while ajmaline acted only in 50 %, and the difference of equieffective doses in CaCl 2- and aconitine-induced arrhythmias was about one thousand fold.
28 citations
TL;DR: A linear relation between the maximum velocities and the σ+-values for direct conjugation was established, leading to some conclusions concerning the mechanism of the splitting-off of aldehyde.
Abstract: The Michaelis constants of yeast pyruvate decarboxylase at full substrate activation and the maximum decarboxylation rates were determined from a total of 21 aliphatic and aromatic α-oxo acids in the absence of buffer substances By means of a pyruvamide-activated enzyme it was possible to confirm experimentally the Km-values obtained by extrapolation The substrate binding rate of pyruvate decarboxylase increases linearly with increasing H+ concentration, which indicates that only the undissociated pyruvic acid acts as the substrate of the enzyme Whilst the substrate binding rate can be correlated linearly with the steric substituent constants of aliphatic α-oxo acids, it was not possible to find a corresponding relation between the aromatic α-oxo acids and the Hammett σ-constants, which indicates steric peculiarities in the active centre of pyruvate decarboxylase On the other hand, a linear relation between the maximum velocities and the σ+-values for direct conjugation was established, leading to some conclusions concerning the mechanism of the splitting-off of aldehyde
28 citations
TL;DR: In this paper, ausammenfassung α-Ketosauren bilden in unpolaren Losungsmitteln ein stabiles Protonenchelat zwischen der Carboxylgruppe und der α-Carbonylgruppe aus, das den n-π-*-Ubergang der α -CarbONYl-gruppe im Vergleich zum Spektrum des unchelatisierten Molekuls stark bathochrom verschiebt und ausser
24 citations
TL;DR: In this paper, a Berry-pseudorotation (Δ G * 25 = 18.3 kcal/mol) and a ring-inversion between four different conformations of these molecules are proposed.
22 citations
01 Dec 1973
TL;DR: The species of the genusVicia are characterized by a significant karyological differentiation in regard to the number and morphology of chromosomes and to the DNA content of the genomes.
Abstract: The species of the genusVicia are characterized by a significant karyological differentiation in regard to the number and morphology of chromosomes and to the DNA content of the genomes. Some species groups represent descending dysploid series; polyploidy has been found only in few perennial taxa.
20 citations
20 citations
TL;DR: The results reported in this communication suggest that plastid ribosome deficient mutants are more common than hitherto assumed.
19 citations
01 Dec 1973
TL;DR: In this paper, the experimental results of karyotype analysis and progeny testing of two lines of Vicia cordata have been discussed, these strains can be used as a model illustrating an initial speciation.
Abstract: The species of the genusVicia are characterized by a significant karyological differentiation in regard to the number and morphology of chromosomes and to the DNA content of the genomes. Some species groups represent descending dysploid series; polyploidy has been found only in few perennial taxa. The species are strongly separated by internal isolation factors, incompatibility and hybrid sterility being the most important ones. InVicia the speciation process is initiated by chromosomal rearrangements as an isolation mechanism, protected by this genetical barrier a divergent evolution of the new derivates may happen, the rate and the scale of it being dependent on the direction and force of the selection pressures. The self-pollination of most of the annual species ofVicia favours this process of quantum speciation even if the other isolation mechanisms are still imperfectly developped in the beginning of the speciation process. By this means a sympatric speciation is also possible, this is supported by distribution patterns of species in some groups of the genus. In this paper the experimental results of karyotype analysis and progeny testing of two lines ofVicia cordata have been discussed, these strains can be used as a model illustrating an initial speciation. The plants of them are very similar in morphological respect, their karyotypes however are clearly differentiated, the differences between them being in the same order as between good species of theVicia sativa complex. TheV. cordata strains are genetically isolated (besides their autogamy) by an incompatibility barrier, the fertility of the heterozygous individuals is however only slightly reduced. One of these strains has a karyotype typically for the speciesV. cordata while the structurally changed one of the second strain results from a chromosomal interchange. It is possible to identify those chromosomes involved in the reciprocal translocation by a comparison of the mitotic complement of both the strains, by the meiotic behaviour of their hybrids and by cytological testing of their progenies. Similar interchanges should be due to the karyotype evolution within theV. sativa complex at all according to the discussed dates. Some of the chromosomes of these taxa however have not been affected by major structural rearrangements, they are forming regular bivalents in the species hybrids indicating thus an high degree of homology. The utilization of interspecific gene transfer by recombination seems therefore possible for breeding purposes. We suppose that quantum speciation with a primary development of internal isolation followed by phylogenetic divergence is an important evolutionary pathway within many mainly annual and autogamous plant groups.
TL;DR: In this article, a total dosage up to 1 mg PGF 2a as i.v. infusions of 10-40 μg/min was investigated on patients with arrhythmias of several kinds.
TL;DR: In this article, the Synthese von α-Amino-chlormethylketonen 1, 2 aus Aminosauren mit freier and N-alkylierter Aminogruppe was beschrieben.
Abstract: Es wird die Synthese von α-Amino-chlormethylketonen 1, 2 aus Aminosauren mit freier und N-alkylierter Aminogruppe uber die Diazoketone sowie die Darstellung der entsprechenden Aminosaurehydrazide 4 beschrieben. Durch Kupplung von N-Acylaminosauren mit α-Amino-chlormethylketonen und Abspaltung der Schutzgruppe wurden α-Amino-chlormethylketone von Peptiden mit freier N-terminaler Aminofunktion (3) erhalten.
Es wird auf die Eigenschaften der Verbindungen und speziell die Instabilitat der α-Aminoketone eingegangen.
TL;DR: In this paper, the Ester in glatter Reaktion zu 1,3-Azarsolidin-2-carbonsauren 1-6 bzw deren Estern reagieren, werden im Falle der β-Ketocarbonsaureester je nach den Reaktionsbedingungen.
Abstract: Wahrend sekundare 2-Aminoathylarsine, RAs(H)CH2CH2NHR′ mit α-Ketocarbonsauren und deren Ester in glatter Reaktion zu 1,3-Azarsolidin-2-carbonsauren 1–6 bzw deren Estern reagieren, werden im Falle der β-Ketocarbonsaureester je nach den Reaktionsbedingungen entweder die 1,3-Azarsolidin-2-essigsaureester 11 oder Enaminoester 10 erhalten Die Umsetzung der γ- und δ-Ketocarbonsauren und deren Ester mit 2-Aminoathylphenylarsin liefert bicyclische 1,3-Azarsolidin-2,3-γ- bzw -δ-lactame 12, und 13 Die Eigenschaften der einzelnen Substanzklassen werden beschrieben
TL;DR: The 1,3-benzazarsoline derivates of o -Aminophenylarsines are obtained by reduction of o-nitrophenylarsonic acid.
TL;DR: In this paper, a differential scanning calorimeter and density measurement were used to investigate 4,4′-di-nhexadecyloxy- and octidecyloxyazoxybenzene.
Abstract: 4,4′-di-n-hexadecyloxy- and octadecyloxyazoxybenzene have been investigated by means of a differential scanning calorimeter and the latter also by density measurement. Both substances exhibit smectic B and C modifications, which have been proved by miscibility investigation. Under favourable circumstances both types of modifications may exhibit schlieren textures.
01 Dec 1973
TL;DR: A total of 1330 spring barley varieties of the Gatersleben collection was tested with ten races of Erysiphe graminis hordei, with resistance to some of the races shown by 123 local varieties and cultivars shown.
Abstract: Insgesamt 1330 Sommergersten des Sortiments Gatersleben wurden mit zehn Rassen vonErysiphe graminis f. sp.hordei, darunter auch Rassen mit Virulenz fur die Resistenztrager ‘Emir’, ‘Amsel’ und ‘Lyallpur 3645’, gepruft.
TL;DR: In this article, the IR-Spektren der dargestellten Verbindungen werden mitgeteilt, e.g., aus n-Butyllithium bzw.
Abstract: Aus Natrium-phenylphosphid und γ-Chlorpropylmercaptan bzw. Cyclohexensulfid werden die ω-Mercaptoalkyl-phenyl-phosphine 1 bzw. 2 hergestellt. Diese sowie das β-Mercaptoathyl-phenylphosphin 3 werden u.a. als Ammonium-dithiophosphinate charakterisiert und reagieren mit Sauerstoff unter Isomerisierung zu Alkyl-phenylphosphin-sulfiden. n-Butyllithium bzw. Natrium metallieren 1–3 primar an der SH- und sekundar an der PH-Gruppierung. 3 wird durch Chlorameisensaure-athylester bzw. Acetylchlorid bei einem Molverhaltnis von 1:1 an der SH-Gruppe acyliert; ein Uberschus von Acetylchlorid acyliert auch die PH-Gruppe. Athylen- und Propylenoxid reagieren mit 1–3 unter Addition an die SH-Funktion. Phenylisocyanat dagegen setzt sich zunachst mit der PH-Funktion von 2 bzw. 3 unter Bildung der Carbamoyl-phosphine 17, 18 um. Mit uberschussigem Isocyanat reagiert dann auch die Mercaptogruppe. Phenylisothiocyanat reagiert nur im Molverhaltnis 1:1, z.B. zu β-Mercaptoathyl-phenyl-(N-phenyl-thiocarbamoyl)-phosphin 19, welches sich durch intramolekulare H2S-Abspaltung in 3-Phenyl-2-phenyl-imino-1,3-thiaphospholan 25 uberfuhren last. Die Carbamoyl- bzw. Thiocarbamoylmercaptoalkylphosphine setzen sich mit Aminen zu den ω-Mercaptoalkyl-phenylphosphinen und disubstituierten Harnstoffen bzw. Thioharnstoffen um. Die IR-Spektren der dargestellten Verbindungen werden mitgeteilt.
TL;DR: In this paper, 1H and 31PNMR parameters are reported for dimethylaminomethylene phosphoranes (1 to 4), and the reaction of NaNH2 gives 4.
Abstract: Es Werden die 1H- und 31PNMR-Spektren der Dimethylamino methylen-phosphorane
mitgeteilt und ein einfaches Herstellungsverfahren fur 4 beschricben.
1H and 31PNMR parameters are reported for dimethyl-aminomethylene phosphoranes (1 to 4). The reaction of
with NaNH2 gives 4.
TL;DR: In this article, the Acylierung der Aminopropylphosphine erfolgt ausschlieslich am Stickstoff, wahrend die Alkylierung tertiare Phosphine liefert.
Abstract: Durch radikalische Addition von Phenylphosphin an Allylamin bzw. dessen N-substituierte Derivate werden sekundare (3-Aminopropyl)-phenylphosphine 1 synthetisiert. Die Acylierung der Aminopropylphosphine erfolgt ausschlieslich am Stickstoff, wahrend die Alkylierung tertiare Phosphine liefert. Mit Carbonylverbindungen erfolgt intramolekulare Cyclokondensation im Sinne einer modifizierten MANNICH-Reaktion unter Bildung der 1,3-Azaphosphorinane 8. Diphenyldisulfid oder elementares Brom oxydieren Aminopropylphosphine zu 1,2-Azaphospholanen 10.
TL;DR: The assumption of sphere-like carrier particles relationships describing the degree of substrate transformation in diffusion-controlled flow enzyme reactors and enzyme columns as a function of the kinetic parameters, the enzyme concentration, the partition coefficient of the substrate between free solution and carrier, the flow rate and the diffusivity of substrate are derived.
Abstract: With the assumption of sphere-like carrier particles relationships describing the degree of substrate transformation in diffusion-controlled flow enzyme reactors and enzyme columns as a function of the kinetic parameters, the enzyme concentration, the partition coefficient of the substrate between free solution and carrier, the external or initial substrate concentration, the flow rate and the diffusivity of substrate are derived. These relations include the case of negligible diffusion effects as a limiting case. The turnover equations (cf. Eqns. (13) and (20)) will aid in the comparison between free and insolubilized enzymes, in the design of preparativescale reactors as well as in the estimation of the apparent kinetic parameters.
TL;DR: In this paper, the DCCI coupling rates with Boc-Gly and BocVal-Acp on Merrifield-resins and 8% crosslinked macroporous resins were determined quantitatively and the influence of the two supports on the rate of peptide chain lengthening investigated.
TL;DR: In this article, a lineare Beziehung der Carbonylfrequenzen, chemischen Verschiebungen, and Halbstufenpotentiale zu den HAMMETT-Konstanten der Substituenten gefunden is discussed.
Abstract: Zum Studium des Substituenteneinflusses an 1,2-Dicarbonsaureimiden werden ihre IR-, UV-, NMR-Spektren und Polarogramme untersucht. Es wird eine lineare Beziehung der Carbonylfrequenzen, chemischen Verschiebungen und Halbstufenpotentiale zu den HAMMETT-Konstanten der Substituenten gefunden. Zur Erklarung der Substituenteneffekte an Maleinimiden ist eine gewisse Delokalisation der Imid-Ring-Elektronen anzunehmen.
TL;DR: In this paper, the influence of the electronic band structure on the thermoelectrical properties of BixSb1-x-alloys (0 ≦ (1 − x) ≦ 1) was investigated.
Abstract: Es wird der Einflus der elektronischen Bandstruktur auf die thermoelektrischen Eigenschaften von BixSb1–x-Legierungen (0 ≦ (1 – x) ≦ 1) untersucht. In dem Legierungsbereich mit hoher thermoelektrischer Effektivitat sind die differentielle Thermokraft und der Quotient aus elektrischer und thermischer Leitfahigkeit gleichermasen an dem Anwachsen des Gutefaktors (relativ zu reinem Wismut) beteiligt. Es zeigte sich, das die Abnahme von Beweglichkeitsverhaltnissen von Ladungstragern unterschiedlichen Vorzeichens uberkompensiert wird durch Veranderungen der partiellen Seebeck-Koeffizienten. Das resultiert aus Modifikationen in der elektronischen Bandstruktur und aus einer Verschiebung der Fermigrenze in einem m-Bandmodell mit m > 2. Hierdurch wird auch die elektrische Leitfahigkeit und die Warmeleitfahigkeit unterschiedlich beeinflust.
The authors investigate the influence of the electronic band structure on the thermoelectrical properties of BixSb1–x-alloys (0 ≦ (1–x) ≦ 1). For alloys with a high figure of merit the differential thermoelectric power and the ratio σ/k (σ: electrical conductivity, k: thermal conductivity) give an equal share to the increase of the figure of merit (in relation to pure bismuth). It become evident that the descrease of ratios of mobility for free carriers with different sign is overcompensated by means of modifications of the partial Seebeck coefficients. This is a result of changes in the electronic band structure and in the position of the Fermi level in an m-band-model with m > 2, impairing the electrical conductivity and the thermal conductivity in different wise.
TL;DR: There was a conspicuous correlation between the occurrence of additional variants of alanine aminopeptidase and the presence of diseases of the biliary tract which in part could be detected only on reexamination.
TL;DR: Die Eingliederung der Formenkreise von Angelica archangelica L. und A. lucida L. werden mit morphologischen Merkmalen begrundet, die jedoch eng miteinander verwandt sind durch Arealkarten und Arealdiagnosen veranschaulicht.
Abstract: Die Eingliederung der Formenkreise von Angelica archangelica L. und A. lucida L. und ihre Stellung innerhalb der Gattung Angelica L. werden mit morphologischen Merkmalen begrundet.
Sie werden zwei verschiedenen Sektionen, der sect. Coelopleurum (Leder.) Pimen. und der sect. Archangelica Regel der Gattung Angelica L. zugeordnet, die jedoch eng miteinander verwandt sind.
Die zirkumpolare vorwiegend holarktische Verbreitung der Gattung Angelica L. und die Verbreitung der Arten der Sektionen werden durch Arealkarten und Arealdiagnosen veranschaulicht. A. archangelica L. wird in die subsp. archangelica mit den var. decurrens (Ledeb.) comb. nov., f. decurrens, f. tschimganica (Korov.) comb. nov., f. komarovii (Schischk.) comb. nov., f. himalaica (Clarke) comb. nov., var. sativa (Mill.) Rikli und in die subsp. litoralis (Fries) Thell. gegliedert.
The species of the Angelica archangelica L.-group and Angelica lucida L.-group are included in Angelica L. based on morphological coincidences and simularities.
Both related groups represent different section, the sect. Coelopleurum (Ledeb.) Pimen. and sect. Archangelica Regel of the genus Angelica L.
The area of Angelica L. shows an holarctic distribution (fig. 1). A map and diagnoses give an idea of the distribution patterns of the species. They generally occur in mesic sites along rivers often also along the edge of forests. A. archangelica L. is divided into subsp. archangelica with var. decurrens (Ledeb.) comb. nov., f. decurrens, f. tschimganica (Korov.) comb. nov., f. komarowii (Schischk.) comb, nov., f. himalaica (Clarke) comb. nov., var. sativa (Mill.) Rikli and subsp. litoralis (Fries) Thell.
TL;DR: In this paper, the 1 H NMR spectra of HCPR 2 (NMe) 2 R = Me, Et, n−Bu) O = Me 2 NH 2 ]X and the products of their slow dismutation are and HC(NMe 2 ) 3.
TL;DR: In this article, the elastic compliances s11 and s′11 for the [110]-direction as well as the morphic piezoelectric moduli d31 and d33 are determined.
Abstract: Fur das ferroelektrische GMO wurden die elastischen Nachgiebigkeiten s11 und s′11 fur die [110]-Richtung sowie die morphischen Piezomoduln d31 und d33 bestimmt. Alle diese Stoffgrosen steigen bei Annaherung and den Umwandlungspunkt an. Die Ergebnisse lassen einige qualitative Aussagen uber Kopplungen mit den Umwandlungsparametern im Rahmen der thermodynamischen Theorie zu.
The elastic compliances s11 and s′11 for the [110]-direction as well as the morphic piezoelectric moduli d31 and d33 are determined. All these coefficients increase with rising temperature up to the transition point. Some qualitative conclusions can be drawn about the coupling with the transition parameters in terms of the thermodynamic theory.
TL;DR: In this article, the synthesis and reactivity of ω-phenylarsino carboxylic acids, amides, and esters were studied. But the synthesis of secondary ω -phenylarboxyly acids from 2 and 3 has not been studied.
Abstract: Ausgehend vom Natrium-diphenylarsid und Chlorcarbonsauren bzw. deren Amiden oder Estern sind im fl. NH3 die entsprechenden Diphenylarsinocarbonsauren und Derivate leicht zuganglich. Die Eigenschaften und Reaktionen der Verbindungen werden beschrieben. Uber die Synthese der sek. ω-Arsinocarbonsauren PhAs(H)(CH2)nCOOH aus 2 und 3 wird berichtet.
Organo-arsenic Compounds. XX. Synthesis and Reactivity of Diphenylarsino Carboxylic Acids
Natrium diphenylarside reacts with chlorocarboxylic acids and their amides or esters in liquid ammonia to give the corresponding diphenylarsino carboxylic acids, amides, and esters. Their properties and some reactions are described. The synthesis of secondary ω-phenylarsino carboxylic acids from 2 and 3 has been studied.