Feldionen- und Elektronenstoß-Massenspektrometrie von Polymeren und Copolymeren, 5. Aliphatische und aromatische Polyamide und Polyimide

The aliphatic polyamides polyamide-6 ( 1 ), and polyamide-6,6 ( 2 ), the aromatic polyamides of terephthalic acid with different diamines [p-phenylenediamine, ( 3 ), 4,4′-biphenylylenediamine, ( 4 ), 4,4′-oxydianiline, ( 5 )] as well as polyimides of pyromellitic acid with aliphatic diamines [ethylenediamine, ( 6 ), hexamethylenediamine, ( 7 )] and aromatic diamines [4,4′-biphenylylenediamine, ( 8 ), 4,4′-methylenedianiline, ( 9 ), 4,4′-isopropylenedianiline, ( 10 ), 4,4′-oxydianiline, ( 11 )] were pyrolyzed at temperatures between 800 K and 1073 K within the vacuum of the high temperature inlet system of a field ion mass spectrometer. Amines, amides, imides and nitriles are characteristic fragments of the thermal degradation. The degradation mechanisms which are determined by structure and amount of the thermal decomposition products, are described.     

Molmassenverteilung und lösungszustand von linearen polyethylenen, 1. Lichtstreuungs-, viskositäts- und GPC-messungen

Light scattering, viscosity and GPC measurements were performed on a homologous series of linear polyethylenes with viscosity average molar masses in decahydronaphthalene at 135°C between 1,0 · 10⁵ and 2,7 · 10⁶ g · mol^?1 and relatively broad molar mass distributions. 1,2,4-Trichlorobenzene, α-chloronaphthalene, decahydronaphthalene (decalin) and decane were used as solvents. In the case of linear polyethylene in decahydronaphthalene and decane relationships between intrinsic viscosity and weight average molar mass were established. The values of the weight average molar masses obtained by light scattering are considerably higher than those obtained by viscosity and GPC measurements. These discrepancies are explained by molecular aggregation of the polyethylene macromolecules.     

RhodosporidiumBANNO: Dosiseffektbeziehungen,Mutageneffektivität und Mutantenspektrum bei der Induktion Auxotrophie verursachender Mutationen durch ultraviolettes Licht und N-Methyl-N′-nitro-N-nitrosoguanidin

The kinetics, efficiency, and specificity of induction of forward mutations to auxotrophy by ultraviolet light (UV) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) was examined in stationary phase cells of Rhodosporidium (Rhodotorula) wild strain Rgl. In comparison to the spontaneous level the frequency of auxotrophic mutants was increased more than 1000 times by both mutagens, however, the mutagenic efficiency of MNNG was higher than that of UV. We found that the forward mutation rate is a linear function of the applicated UV and MNNG doses in the range to 600 J m^?2 or 25 mm x min, respectively. The 35 studied biosynthetic pathways to amino acids, purines, pyrimidines, and vitamins are genetically blocked at different frequencies, but there is not any significant difference between UV and MNNG induced frequencies of mutants with a specific requirement. However, in difference to the approximately equal distribution of the MNNG-induced nic mutants among the genetic blocks of the tryptophan-nicotinamide pathway, UV-induced nic mutants occurred with a higher frequency in the genes of the tryptophan pyrrolase and the 3-hydroxykynureninase than in the genes of the other enzymes of the pathway.     

Synthese und eigenschaften von äthylenterephthalat-pleionomeren,

In order to synthesize the higher oligomers and pleionomers of ethylenterephthalate with methylester endgroups in pure form, the monomethylesterchlorides of the mono-. di-, and trimeric dicarboxylic acids were synthesized. The synthesis of the desired dimethylesters was effected by using the monomethylesterchlorides as earboxylic components and glycol and some oligoesterdiols as bifunctional fragments. The heptameric and higher dimethylesters can be considered pleionomers because they do not differ in some solubility, melting point, IR-spectrum, and DEBYE ogramm from the polymer.     

Feldionen- und Elektronenstoß-Massenspektrometrie von Polymeren und Copolymeren, 3. Copolymere des α-Methylstyrols mit Methylmethacrylat und Acrylnitril

Pyro-field ion mass spectrometry was used to study the primary fragments as well as the depolymerization behaviour of some α-methylstyrene (α-MS) copolymers. α-MS-methyl methacrylate (MMA) copolymers, when pyrolyzed, decompose mainly into the two monomers. The zip-depolymerization usually proceeds through the whole chain, disregarding the hetero-links between different monomeric units. Hetero-fragments are formed only with a small probability; still lower is the concentration of homo-dimers in the pyrolysate. Primary fragments of poly(acrylonitrile) (PAN) are acrylonitrile (AN), (AN)₂, (AN)₃, HCN, C₃H₅CN, C₄H₇CN, C₅H₉CN and higher nitriles. During pyrolysis of α-MS-AN copolymers, α-MS sequences zipdepolymerize with formation of the monomer. This retropolymerization stops at heterolinks, and fragments of the type α-MS-AN or α-MS-(AN)₂ are formed. Long AN sequences in the copolymer cause, as PAN itself, formation of AN oligomeres as well as higher alkene cyanides. Isolated AN units lead to the formation of monomeric AN.     

Lösungs- und verdünnungswärmen von polyethylenglykolen in wasser und benzol, 1. Experimentelle ergebnisse

Dissolution and dilution enthalpies of poly(ethylene glycol)s were measured in water and benzene, resp., by microcalorimetry. The enthalpies depend on both solute concentration and molar mass, indicating interactions between hydroxyl endgroups, ether groups and solvent molecules. Low molar mass samples form hydrogen bonds between hydroxyl and ether groups at solute concentrations of 0,003 g/cm³ and higher. High molar mass samples form intermolecular associates through dispersion forces at concentrations above 0,06 (benzene) and 0,1 g/cm³ (water).     

Wirkung von Ölen und Fettsäuren auf Wachstum und Enzymbildung bei Thermoactinomyces vulgaris III. Einfluß von Kulturgefäßen,Stammaterial und Medienzusammensetzung

The influence of rape-oil as antifoam agent on growth and protease synthesis of T. vulgaris was studied. The turbulence and the aeration conditions caused by the culture vessel have a fundamental importance for the so-called oil effect. A higher aeration rate induces an enhanced lysis of the mycelium and consequently a reduced enzyme synthesis. The tentency to lysis of the mycelium at different selectants is variable. The addition of oil to the culture medium reduces this tendency and promotes the protease production. The oil effect on the enzyme synthesis is higher in deficient medium than in full one.     

Über polyenarylene und polyenheteroarylene. 2. Mitt.: Poly-[thienylen-(2.5)-äthenamer-alt-phenylen-(p,m,o)-äthenamer] und einige oligomere. Synthese,spektrales verhalten und elektrische leitfähigkeit

Starting with 2.5-bis(triphenylphosphoniomethyl) thiophene dichloride and terephthalic, isophthalic and phthalic aldehyde the poly[thienylene-(2.5)-ethenamer-alt-phenylene-(p,m,o)-ethenamers] were prepared via the WITTIG reaction. These polymers have terminal aldehyde groups. The poly[phenylene-p-ethenamer-alt-phenylene-(p,m,o)-ethenamers] and some oligomers with 3 aromatic systems and 2 vinylene groups respectively oligomers with 5 aromatic systems and 4 vinylene groups were prepared in an analogous manner. These polymers and oligomers were characterized by their UV, visible, IR and mass spectra. X-ray diffraction patterns were made for further information about the solid state of these products. The electrical conductivity of the oligomers and polymers was investigated.     

Thrombozytentransfusion: Klinik,Kontrollen und Komplikationen

Summary Thrombocytopenia is the most common cause of bleeding tendency, and, if due to impaired platelet production, is best treated by platelet transfusions. Prophylactic transfusions for asymptomatic patients should be considered if platelet count is below 20000/l. However, if bleeding occurs or surgery is inevitable, platelet count should be maintained above 50000/l. The benefit of platelet transfusions has to be balanced against risks like fever, infections and haemolysis.The effectiveness of platelet transfusions should be examined after 1 and 24 hrs by measuring the corrected count increment (CCI). Not only alloimmunization is a reason for unsatisfactory platelet increments. A poor CCI can also be due to fever, sepsis, hepato-splenomegaly or special drugs, which must be taken into account when assessing the demand for platelet transfusions.

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Abkürzungsverzeichnis ALL akute lymphatische Leukämie - AML akute myeloische Leukämie - ARDS Adult Respiratory Distress Syndrome - BZ Blutungszeit - CCI Corrected Count Increment - CML chronische myeloische Leukämie - CMV Cytomegalievirus - DCT direkter Coombstest - DIC disseminierte intravasale Gerinnung - EK Erythrozytenkonzentrat - GVHD Graft Versus Host Disease - KG Körpergewicht - KMT Knochenmarktransplantation - PML Promyelozytenleukämie - PRP plättchenreiches Plasma - PTP post-transfusionelle thrombozytopenische Purpura - SSA schwere aplastische Anämie - TK Thrombozytenkonzentrat - VK Variationskoeffizient     

Polypropylenglykol in lösung,zahlenmittelmolekulargewicht und reibungsverhalten

Molecular weights of poly(propylene glycol) are determined by measurement of the elevation of the condensation temperature and of the boiling temperature. For determination of the condensation temperature elevation, a new apparatus with 8 thermoelements is described. The physically determined M_n-values were somewhat lower than those determined chemically by the hydroxyl number. The solution behaviour of the polymer was tested by diffusion measurements in acectone and benzene. From M_n = 4000 down to very low molecular weights, diffusion coefficients D are observed yielding constant exponents in the relation D = K·M^?b with b = 0.52 for acetone and 0.55 for benzene.     

Über Polyarylenalkenylene und Polyheteroarylenalkenylene, 4. Synthesen und Charakterisierung von Poly(2,7-fluorenylenvinylenarylenvinylen)en und einigen dazugehörigen Oligomeren

Some poly(2,7-fluorenylenevinylenarylenevinylene)s ( 3a–c ) and some of their corresponding oligomers were prepared via the Wittig-reaction starting from 2,7-fluorenedicarbaldehyde ( 1 ) and “mono- and bis-Wittig-salts” of the benzene and thiophene series. 2-Fluorenecarbaldehyde ( 6 ) submitted to the same reaction with “mono- and bis-Wittig-salts” gave an additional series of oligomers. These polymers and oligomers were characterized by elemental analyses and by their IR- and electronic spectra–the oligomers in addition by their mass spectra. The electrical conductivities of the polymers and oligomers were investigated as well as the thermooxidative degradation of the polymers and of some oligomers.     

Proteinkristalle und Tubuli-Bündel in Hefezellen. II. Isolierung,biochemische und elektronenmikroskopische Charakterisierung

A purified fraction of crystals stabilized with Cd²⁺ is prepared from Saccharomyces carlsbergensis protoplasts by means of differential centrifugation. As proved by negative staining the crystals are hexagonal with well preserved surface which in its turn also reveals a hexagonal fine structure. Crystals are digestible by pronase (1 mg/ml) in phosphate buffer (pH 7.4). The molecular weight of protein subunits is 38000 ± 300 D. Amino acid composition of the crude crystal protein is similar to that of microtubular protein (MTP) from brain and sperm, except that lysin content is much higher. The crystal protein exhibits more differences, however, after purification by preparative gel electrophoresis. The level of glycine, alanine, and valine is increased, whereas that of glutamic acid is decreased.     

Modifizierte ionenaustauscherharze — synthese und eigenschaften, 2. Synthese sulfoethylierter und sulfopropylierter styrol-divinylbenzol-harze

Sulfomethylated and sulfopropylated resins were prepared by polymer analogous reactions, starting from macroporous poly(styrene-co-divinylbenzene) matrices. Different reaction paths were used in the synthesis. It could be shown that sulfoalkylation can be achieved directly by reaction of the polystyrene resins with sultones. Alternatively, haloalkylated matrices were prepared and by halogen/sulfo-substitution the corresponding ion exchange resins.     

Kinetik der Bromierung von Phenolen und phenolischen Mehrkernverbindungen, 1. Mechanismus und meßmethode

The bromination of 2-(2-hydroxy-5-methylbenzyl)-4,6-dimethylphenol ( 1 ) and 2-[2-hydroxy-3-(2-hydroxy-5-methylbenzyl)-5-methylbenzyl]-4,6-dimethylphenol ( 2a ) was investigated in acetic acid at 22°C. For [Br₂]₀=1,4·10^?3 and 6,0·10^?3mol dm^?3 and for concentrations of the phenolic compounds [P]₀ between 1,1·10^?3 and 5,5·10^?3 mol dm^?3 the reaction can be described by the following rate law: The brominated compound formed during the reaction shows no influence on the reaction rate, which, however, is decreased by hydrogen bromide. In spite of this, the bromination is very suitable for the determination of the reactivity of phenols and oligonuclear phenolic compounds, because the reaction can be followed easily by measurement of the absorbance of bromine at 450nm. For small conversions (15%) a second order rate law was assumed and the obtained second order rate constant k′₂ was determined as a function of the bromine concentration.     

Nucleosidpolyphosphate: Vorkommen,Metabolismus und Funktion

Procaryotes have regulatory systems allowing to vary the metabolism in response to nutritional variations, to reduce the growth, and to start development. Nucleoside polyphosphates are mediators of coordinated alterations of metabolism. In this review, after a brief recall of the characteristics of the stringent response, the occurrence, determinations, and the metabolism of the nucleoside polyphosphates are presented. The representation of the pleiotropic effects includes the regulation of the protein synthesis and of the protein synthesis apparatus, of the protein turnover, of the N- and carbohydrate metabolism, of the formation of cell membranes and cell walls as well as the possible function of the development.     

Über die zusammenhänge,zwischen den exponenten in den beziehungen zwischen molekulargewicht einerseits und staudinger-index,sedimentationskoeffizient und diffusionskoeffizient andererseits

The preparation of 3.4-diaminostyrene from 1-(3′.4′-diamino-phenyl)ethanol as well as from 3.4-diamino cinnamic acid is accompanied by the formation of 3.4-diaminoethylbenzene as by-product. 3.4-Diaminostyrene is prepared without by-product by the reduction of 3-nitro-4-aminostyrene; it can be condensed to corresponding vinylheterocycles.     

Über Polyarylenalkenylene und Polyheteroarylenalkenylene, 7. Die Anwendung von HMO-Rechnungen auf elektronenspektroskopische und struckturanalytische Probleme oligomerer und polymerer Polyarylenalkenylene und Polyheteroarylenalkenylene

For the homologous series of the di-2-thienyl- and diphenylalkapolyenes with one to six olefinic double bonds and the oligomeric arylene- respectively 2,5-thienylenevinylenes and 2,5-thienylene-1,3-butadienylenes we have calculated by the HMO method the energy values of π → π^* transition (Δx_j values), which are in good agreement with the λ_max values (π → π^* transitions). We have also calculated the bond orders for the carbon-carbon bonds of all of these compounds. From the calculated bond orders one can see, that the adaptation of the bonds is reached for the tetramers or pentamers. The bond lengths of 5 simple oligomers-estimated by X-ray diffraction patterns-are in good agreement with the calculated bond orders corresponding to the adaptation of their bonds in such conjugated π-electron systems.