Showing papers by "University of Mainz published in 1972"

Topochemical polymerization of monomers with conjugated triple bonds

Abstract: Solid-state polymerization of monomers with conjugated triple bonds turns out to be a versatile method for synthesis of crystalline polymers of high molecular weight exhibiting a fully conjugated backbone. The reaction is best described as an 1.4-addition polymerization of the conjugated triple bonds giving rise to a polymer with three cumulated double bonds per repeating unit. The all-trans configuration of the substituents is a consequence of the solid-state reaction mechanism and is already predetermined by the packing of the molecules in the monomer lattice. It was shown by X-ray analysis in the case of poly(2.4-hexadiin-1.6-diol-bis-phenylurethane) that the polymer diacetylenes can be described by either a butatriene structure or by a mesomeric en-in-structure. Polymerization of the colorless monomer crystals is achieved by irradiation with UV- or high-energy radiation or by simply annealing the monomer crystals below their melting point. Deep red, blue or black polymer crystals are obtained exhibiting strong dichroism with the fibre axis as the direction of main absorption. These crystals possess semiconducting properties (EA = 0.6–1.0 eV, depending on the substituents at the conjugated backbone). Die Festkorperpolymerisation von Monomeren mit konjugierten Dreifachbindungen ist eine vielseitige und einfache Methode zur Synthese von kristallinen Polymeren mit einer vollkommen konjugierten Hauptkette und hohem Molekulargewicht. Die Polymerisation last sich am besten als eine 1.4-Additionsreaktion der konjugierten Dreifachbindungen beschreiben. Dabei entsteht ein Polymeres mit 3 kumulierten Doppelbindungen pro Grundbaustein. Die trans-Konfiguration der Substituenten ergibt sich zwanglos aus dem Mechanismus der Festkorperpolymerisation und wird durch die Packung der Monomermolekule im Kristallgitter vorherbestimmt. Aufgrund der Strukturdaten aus einer Rontgenstruktur-analyse des Polymeren aus 2.4-Hexadiin-1.6-diol-bis-phenylurethan mus angenommen werden, das die polymeren Diacetylene entweder durch die Butatrien-Struktur oder eine mesomere en-in-Struktur beschrieben werden konnen. Die Polymerisation der farblosen Monomerkristalle wird durch Bestrahlung mit UV- oder energiereicher Strahlung oder aber durch Tempern der Monomerkristalle unterhalb ihres Schmelzpunktes bewirkt. Tief rot, blau oder schwarz gefarbte Polymerkristalle werden dabei erhalten, die einen starken Dichroismus aufweisen. Die Faserachse ist die Richtung der Hauptabsorption. Die Polymerkristalle sind Halbleiter. Die Aktivierungsenergie der Leitfahigkeit liegt in Abhangigkeit von den Substituenten an der konjugierten Hauptkette bei 0,6–1,0 eV.

A novel method of determination of reactivity ratios in binary and ternary copolymerizations

Abstract: The determination of reactivity ratios is simplified by using an excess of one monomer (M1) at a time large enough that the copolymers will have a very small content of the other monomer (M2). In this case chain propagation takes place almost exclusively by addition to polymer radicals with a terminal M1-unit (P) and monomer consumption by propagation of P may be neglected. One reactivity ratio (r1) is obtained from monomer conversions by means of a simple integrated equation which is valid up to high conversions. A calculation is proposed in order to account for the neglected propagation via P. The other reactivity ratio (r2) is obtained from copolymerizations with excess M2. As the new method uses an integrated form of the MAYO equation it permits the determination of monomer conversions directly by gas chromatography of unreacted monomers. Thus, if desired, analysis of copolymers can be avoided. The gas chromatographic method has been tested with the radical copolymerization of styrene and methyl methacrylate. In ternary and quaternary copolymerizations the new method offers particular advantages.

The Effect of Dexamethasone on Water and Electrolyte Content and on rCBF in Perifocal Brain Edema in Man

Abstract: The results of clinical studies are reported dealing with the relationship between cerebral edema and regional cerebral blood flow in patients with brain tumor as well as with the effect of dexamethasone on this relationship. rCBF is found to be significantly reduced in brain tissue surrounding brain tumors. Autoregulation as well as cerebrovascular reactivity to PaCO2 is focally or generally impaired. Water content of perifocal white matter is markedly increased. The combination of tissue lactacidosis, low regional blood flow and vasoparalysis seems to be a characteristic finding in this type of local brain edema. The increased local tissue pressure, due to the increased tissue water content, is a main factor responsible for the local flow decrease. A locally elevated tissue pressure will tend to collapse the capillaries and the venules, raise the local cerebrovascular resistance and counteract the vasodilating effect of a low tissue pH.

Topochemical Reactions of Monomers with Conjugated Triple‐Bonds VII Mechanism of Transition from Monomer to Polymer Phase During Solid‐State Polymerisation

Abstract: The lattice-controlled solid-state polymerisation of three different modifications of 2,4-hexadiin-1,6-diol-bis(phenylurethane) was investigated by X-ray and optical methods. The polymerisation is a homogeneous reaction. The polymer grows in the form of single chains within the crystal of the monomer. The chains extend along a definite crystallographic direction. Monomer and polymer are isomorphous and monomer-polymer single crystals of various compositions are obtained up to a quantitative conversion in the case of modification I or III. Phase separation into a mesomorphic polymer and oriented monomer phase was observed on annealing partially polymerised single-crystals of modification II below the transition point to modification III.

Circulatory effects of peridural block: 3. Effects of acute blood loss.

Abstract: High peridural analgesia was studied in 20 volunteers in whom peridural block was achieved before and after removal of 10 ml/kg blood to simulate mild acute hemorrhage. One group was given 2 per cent lidocaine containing 1:200,000 epinephrine, while in another group lidocainc alone was used. The gro

Effects of several muscarinic agonists on cardiac performance and the release of noradrenaline from sympathetic nerves of the perfused rabbit heart

Abstract: Summary 1 The effects of several muscarinic agonists on atrial tension development, ventricular rate and noradrenaline release from terminal sympathetic fibres evoked by electrical nerve stimulation (SNS) and 1,1-dimethyl-4-phenylpiperazinium (DMPP) were measured in isolated perfused rabbit hearts. 2 Hexamethonium, in a concentration which almost abolished the release of noradrenaline by DMPP, had no effect on the release produced by SNS, confirming that the stimulation was postganglionic. 3 The order of potency for inhibition of atrial tension development was N-methyl-1,2,5,6, tetrahydro-nicotinic acid prop-2-yne ester (MH-1)>oxotremorine > acetylcholine > methacholine > carbachol > furtrethonium > pilocarpine>4-(m-chlorophenylcarbamoyloxy)-2-butynyltrimethylammonium chloride (McN-A-343)>N-benzyl-3-pyrrolidyl acetate methobromide (AHR 602). All effects were abolished by atropine (1·4 × 10−6M). 4 Each compound was more potent relative to acetylcholine in inhibiting ventricular rate than atrial tension. With the exception of carbachol, the order of potency was the same. 5 Both AHR 602 and McN-A-343 facilitated the release of noradrenaline by SNS and inhibited that by DMPP. The effects were atropine-resistant and hence non-muscarinic. 6 The muscarinic compounds (except AHR 602 and McN-A-343) each produce atropine-sensitive inhibition of noradrenaline release evoked both by SNS and DMPP although it is likely that furtrethonium and pilocarpine have additional non-muscarinic inhibitory activity against DMPP. The order of potency on both parameters and the potencies relative to acetylcholine were in good agreement with those for inhibition of atrial tension. 7 The results suggest that similar muscarinic receptors mediate inhibition of atrial tension development, ventricular rate and neuronal noradrenaline release caused by SNS and DMPP. 8 In terms of the two muscarinic sites known to be present in the superior cervical ganglion, the receptors of the terminal fibres mediating inhibition of noradrenaline release are more likely to correspond to those mediating hyper-polarization than to those mediating depolarization, for which AHR 602 and McN-A-343 show specificity.

Vibrational analysis of the electronic spectrum of ethylene based on ab initio SCF-CI calculations

Abstract: Ab initio calculations for CH2 twisting and CC stretching vibrational wavefunctions and energy levels are reported for various electronic states of ethylene C2H4. Electronic transition moments between these states are also obtained to allow a calculation of the oscillator strengths for vibrational transitions involved in various electronic band systems; from this study it is concluded that thevertical electronic energy differenceΔE e may differ significantly from the energy of the absorption maximumΔE max with which it is often equated. In particular it is found in the case of theπ→π * singlet-singlet excitation of ethylene that theΔE e value overestimates the most probable vibrational transition energy (7.89 eV) by some 0.4 eV, thereby offering an explanation for the fact that previous attempts to predict the location of theV-N Franck-Condon absorption maximum have consistently obtained substantially higher results than the 7.66 eV value actually observed. Similar calculations for various Rydberg species and for theN-T transition are also found to obtain a quite consistent representation of the electronic spectrum of this system.

Die spektroskopische untersuchung einer cyclischen, tetrameren verbindung aus p‐kresol und formaldehyd

Abstract: In Anlehnung an den Syntheseweg von HAYES und HUNTER wurde eine cyclische, tetramere Verbindung (VII) uber eine linear 4-Kernverbindung (VI) (aus p-Kresol und Formaldehyd) hergestellt. Ihre Struktur wurde spektroskopisch untersucht. Mittels UV- und IR-Spektren last sich VII von der Ausgangsstufe VI und einem Konkurrenzprodukt VIII unterscheiden. Die H-NMR-Spektren der Ringverbindung und ihrer Ausgangsverbindung (VI) stimmen vollstandig mit den angegebenen Strukturformeln uberein; sie geben, bei 20 und 60°C aufgenommen, Hinweise auf bestimmte Konformere der Ringverbindung. Das massenspektrometrisch bestimmte Molekulargewicht (480) stimmt mit dem berechneten (480,6) uberein. Following the syntheses of HAYES and HUNTER a cyclic, tetrameric compound (VII) was prepared by ring closure of a linear four nuclear compound (VI), starting from p-cresol and formaldehyde. The structure of VII was investigated by spectroscopic analysis. By means of UV -and IR- spectra, VII can be distinguished from the starting compound VI and a side product, VIII. The H-NMR-spectra of the cyclic condensate and its starting compound VI are totally identical with the supplied structures. Determined at 20 and 60°C, they give information about certaing conformers of the cyclic compound. The molecular weight (480) received by mass spectroscopic measures, is identical with the calculated value (480,6).

Synthesen mit substituierten Malondialdehyden, XI. γ‐Formyl‐tetramethinmerocyanin‐, γ‐Formyl‐pentamethincyanin‐ und [2.2.2]Heptamethincyanin‐Farbstoffe

Abstract: Durch Kondensation des Formylmalondialdehyds (Triformylmethan) 5 mit heterocyclischen Imoniumsalzen 4 werden je nach Reaktionsbedingungen neuartige γ-Formyl-tetramethinmerocyanin-(6), γ-Formyl-pentamethincyanin-(8) und trinucleare symmetrische [2.2.2]Heptamethincyanin-Farbstoffe (9) dargestellt. Die Isolierung der Mono- (6) und Dikondensationsprodukte (8) des Formylmalondialdehyds ermoglicht die Darstellung unsymmetrischer Farbstoffe 8 und 9 mit verschiedenen Endgruppen. — Die trinuclearen [2.2.2]Heptamethincyanine 9 lassen sich in Analogie zu den phenylogen Guanidiniumionen (Triphenylmethanfarbstoffe) als methinyloge Guanidiniumkationen 3 (n = 3) auffassen. — Die spektroskopischen Eigenschaften der neuen Farbstoffe werden in Abhangigkeit von Struktur (Tab. 1–3) und Losungsmittel (Abbild. 1 und 2) zusammen mit den Ergebnissen einfacher HMO-Rechnungen (Abbild. 7 und 8) mitgeteilt. — Die Nomenklatur der trinuclearen Farbstoffe 9 wird erortert. Syntheses with Substituted Malondialdehydes, XI. γ-Formyl-tetramethinemerocyanine, γ-Formyl-pentamethinecyanine, and [2.2.2]Heptamethinecyanine Dyes Condensation of formylmalondialdehyde (triformylmethane) 5 with heterocyclic imonium salts 4 under suitable reaction conditions yields novel γ-formyl-tetramethinemerocyanine (6), γ-formyl-pentamethinecyanine (8), and trinuclear symmetrical [2.2.2]heptamethinecyanine dyes (9). The isolation of the monocondensation (6) and dicondensation products (8) of formylmalondialdehyde allows the preparation of unsymmetrical dyes 8 and 9 with different end groups. — The trinuclear [2.2.2]heptamethinecyanine dyes 9 may be regarded as methinylogous guanidinium cations 3 (n = 3), by analogy with the phenylogous guanidinium ions (triphenylmethane dyes). — The spectral properties of the new dyes are described as a function of structure (table 1–3) and solvent (fig. 1 and 2) together with the results of simple HMO calculations (fig. 7 and 8). — The nomenclature of the trinuclear dyes 9 is discussed.

Suitability of the isolated perfused rat brain for studying effects on cerebral metabolism.

Abstract: The concentrations of P-creatine, creatine, ATP, ADP, AMP, glycogen, glucose, glucose-6-P, fructose diphosphate, dihydroxyacetone-P, α-glycero-P, lactate and pyruvate were measured in the isolated perfused rat brain as well as in rat brain in vivo. Similar levels were observed in the isolated brain and in intact animals, and the values measured were in good accordance with those described in the literature. Only the pyruvate and lactate content were significantly higher in the isolated brain but the lactate/pyruvate ratio remained unchanged. An anesthetic or ischemia caused just the same effects on energy metabolism of the isolated rat brain as described for intact animals. Thus, 1.5 mM phenobarbital in the perfusion medium produced a statistically significant increase in P-creatine and glucose levels as well as a decrease of pyruvate, lactate and α-glycero-P levels. After ischemia of the isolated brain the concentrations of high-energy phosphates, glycogen, glucose, and pyruvate fell considerably concomitantly with significant accumulations of creatine, AMP, α-glycero-P and lactate. The results indicate that the isolated perfused rat brain may be a useful tool for studying cerebral metabolism.

Association between C′3 phenotypes and various diseases

Abstract: The distribution of C′3 phenotypes in leprosy, rheumatism, diabetes, hyperlipedemia and hepatitis were studied There was a significant excess of FF-phenotypes in patients with rheumatic factor while in hepatitis the SS-phenotype was significantly lower and a relatively high frequency of FF was stated The results are discussed

Long survival time of an isolated perfused rat brain.

Abstract: INVESTIGATIONS on brain metabolism and the effect of drugs on the central nervous system using an isolated brain require a sustained viability of the complete brain for several hours. Survival times of isolated perfused brain preparations have been found to vary among conventional laboratory animals. Thus, EMMENEGGER, TAESCHLER and C E R L E ~ (1963) and BARRETT, INGENITO and PROCITA (1969) gave satisfactory proof of viability of isolated perfused cat brain for up to 2 h. Maintenance of brain functions of cat brain perfused in situ was observed by GEIGER and MAGNES (1947) for 4 h. The longest survival time of an isolated brain has, as far as we know, been reported by WHITE, ALBM and VERDURA (1964) who recorded spontaneous EEG from isolated monkey brain for 7 h. Because of the subtle preparation techniques required to isolate the arterial supply to the brain it is only in recent years that the rat has been used for brain perfusion. THOMPSON, ROBERTSON and BAWR (1968) described an in situ technique in which the rat head was perfused via the aortic arch, whereas the preparation of ANDJUS, SUHARA and SLOVITER (1967) consisted of the completely detached rat skull and its contents, from which the extracranial structures had been removed. ANDJUS et al. (1967) achieved a maximal survival time of 5 h, operating with an open perfusion circuit. In experiments where the perfusion blood was recirculated, most preparations showed spontaneous electrical activity for 1 h. Under our conditions of perfusion, viability was successfully maintained for a much longer time. Male Sprague-Dawley rats weighing 200-300 g were anaesthetized with urethane (1.2 g/kg intraperitoneally) and the isolation of the brain performed according to ANDJUS et al. (1967). ‘Simplified blood‘, consisting of 30 per cent well-washed red cells (from bovine blood not older than 24 h), 4 % (w/v) bovine serum albumin (quality: trocken, ‘reinst’; Behringwerke, Marburg) and 22 mM-glucose in a Krebs-Henseleit solution was used as the perfusion medium. Two apparatuses for recirculation perfusion were developed and will be described elsewhere. Spontaneous electrical activity of the isolated brain was assessed to be a sensitive criterion of metabolic and functional condition. Besides the EEG we examined reflex activities-comeal reflex, pupillary reactions, spontaneous blinking, movements of facial structures after pinching the upper lip-as well as glucose consumption and lactate production measured in the perfusion medium. In order to establish the efficiency of our perfusion method we continued the perfusion in a series of six experiments until the spontaneous EEG disappeared. An average viability of 7 h was observed. In one case the spontaneous EEG persisted for almost 10 h (comparable result in the literature: 2 h; ANDJUS et al., 1967). The shortest experiment lasted 4 h. The bipolar recorded EEG showed in each case an increase in spike frequency during the first 5 min of perfusion (Fig. 1). Continuing perfusion for several hours the amplitude of the EEG decreased and finally disappeared. Concomitantly, the pupils became increasingly dilated and fixed. The corneal reflex could usually be detected during the whole experiment, although reflex movements of remnants of muscle occured only up to a perfusion time of 4 h. Interruption of perfusion for 30 s caused a gradual disappearance of the EEG (Fig. 2). When perfusion was restarted the EEG returned to its previous level. The longer the brain had been perfused the more time was needed to restore the EEG after resuming perfusion. At the same time, the normally constricted pupils dilated then constricted again after resuming perfusion. Application of 10 mg pentylenetetrazol caused convulsive discharge of the EEG. The characteristic spike wave pattern could be induced up to 30 min after the spontaneous EEG had ceased and once present lasted up to 2 h.

Zustände und Reaktionen des Carbanions bei der anionischen Polymerisation des Styrols

Abstract: I. Einleitung: Die 3 Formen der aktiven Endgruppe . . . . . . . . . . 1 II. Experimentelle Methoden . . . . . . . . . . . . . . . . . . . . 5 1. Versuchstechnik . . . . . . . . . . . . . . . . . . . . . . . 5 2. Auswertung der MeBdaten . . . . . . . . . . . . . . . . . . 8 3. Messung der elektrischen Leitf~ihigkeit . . . . . . . . . . . . . t t III. Nebenreaktionen der Initiatorsysteme . . . . . . . . . . . . . . . 12 IV. Die Gleichgewichte zwischen den 3 Formen der aktiven Endgruppe und die Geschwindigkeitskonstanten der Monomeraddition . . . . . . . 24 1. Ergebnisse der Messungen der elektrischen Leitf~ihigkeit . . . . . 24 2. Ergebnisse der kinetischen Messungen . . . . . . . . . . . . . 27 V. Geschwindigkeitskonstanten der Oberg~inge zwischen den 3 Formen der aktiven Endgruppe . . . . . . . . . . . . . . . . . . . . . . . 35 VI. Zusammenfassung der Ergebnisse . . . . . . . . . . . . . . . . 41 VII. Literatur . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Eradicating mosquitoes using translocations: a first field experiment.

Abstract: THEORETICAL considerations have led to the assumption that chromosomal translocations with ensuing semisterility could be used to control pests1–3. Inversions could have the same effect in animals and plants in which crossing over occurs in both sexes4. Many translocations of different type and with various degrees of sterility have been produced in the mosquito Culex pipiens5–8. Preliminary laboratory experiments with these translocations have shown that a cage population can be diminished and finally exterminated after a few generations by the release of translocation heterozygotes into the population9.

Ab initio SCF and CI calculations on the barrier to internal rotation of 1,3-butadiene

Abstract: Ab initio SCF and CI calculations employing a set of gaussian lobe functions have been carried out for the ground and excited states of five geometrical C4H6-structures occurring in the course of rotation from cis-butadiene to the trans-isomer. The rotational potential curves are discussed for the ground and excited states. Particularly the potential curve of the lowest triplet state is considered in this connection thereby substantiating quantitatively the proposed mechanism for induced dimerisation of C4H6. Possible assignments of the lowest singlet excited states in trans-butadiene are discussed.

Temporal retrogasserian resection of trigeminal root versus controlled elective percutaneous electrocoagulation of the ganglion of gasser in the treatment of trigeminal neuralgia. Report on a series of 531 cases.

Abstract: In his experience with 531 surgical procedures for the relief of trigeminal neuralgia between 1955 to 1970, the author developed a strong preference for the percutaneous electro-coagulation of the gasserian ganglion. Although the method was repeatedly modified in the early years, a standardized technique of controlled, selective and fractional coagulation in the semiawake state of neurolept-anaesthesia was used since 1963 in 183 of his 311 patients, treated in this manner. The advantages of the method, particularly in comparison to open intracranial root sections, are: Minimal operative risk, control of operative effect during the operation, small sensibility deficit, low rate of complications, short hospitalization, short convalescence and satisfactory final result in 93% of the patients (after a second or third coagulation, if needed) in a three-year follow-up period.

DNA Content in Nine Species of Nematocera with Special Reference to the Sibling Species of the Anopheles maculipennis Group and the Culex pipiens Group

Abstract: DNA values were determined for the nine species: Telmatoscopus meridionalis (family Psychodidae), Dixa obscura (family Dixidae), and Culiseta litorea, Culex pipiens, Aedes caspius, Anopheles labranchiae, Anopheles atroparvus, Anopheles stephensi, and Anopheles freeborni (family Culicidae). The DNA content indicated that the species could be divided into three categories: The Culex group with Culex pipiens, Culiseta litorea and Aedes caspius containing 1.02, 0.92 and 0.99 pg DNA in the haploid set, the Anopheles group including the four Anopheles species A. labranchiae, A. atroparvus, A. stephensi, A. freeborni and Telmatoscopus meridionalis with 0.23, 0.24, 0.24, 0.29 and 0.24 pg DNA and the third group with Dixa obscura containing 0.16 pg DNA. Within the sibling species of the Anopheles maculipennis group DNA differences were found to be present between the palaearctic and the nearctic populations. No deviations could be found between two Culex pipiens populations which were reproductively isolated.

Thymidine-, uridine- and choline-kinase in rabbit kidney cells infected with herpesvirus hominis, type I and II.

Abstract: Data are presented about the activity of the thymidine-, uridine- and choline-kinase after infection with 21 strains ofherpesvirus hominis of serotype I or II in rabbit kidney cells. Type I strains increase the activity of the thymidine-kinase 15–20 fold over the controls, whereas the type II strains demonstrate a moderate activity, the level of the enzyme is increased 2–5 fold. One giant cell forming strain exhibits unusual properties, the TK activity decreases in correlation to the controls. The uridine- and choline-kinases induce the respective enzymes in different manner. The strains tested are divided into 5 groups depending upon the activity of the enzymatic activity. The implications of the results are discussed.

Die endokrinen drüsen im embryo von Oncopeltus fasciatus Dallas (Insecta, Heteroptera)

Abstract: The differentiation of the endocrine glands in the embryo of Oncopeltus fasciatus is described. The function of these glands can be correlated with the embryonic moults. The nuclei of some tissues already become polyploid in the embryo. It is discussed whether the endomitotic growth is dependent upon the function of the endocrine glands.