Swelling effect onα-relaxation in high density polyethylene

Summary Swelling effects of carbon tetrachloride on the mechanical relaxations in the crystal mat and the melt-crystallized samples of high density polyethylene were studied using a torsion pendulum. A very strong-relaxation peak appears by swelling at the low temperature side of the original-relaxation for the crystal mat. It was shown that this strong-relaxation originates from the slippage between the highly swollen lamellae. For the melt-crystallized sample, the-relaxation peak is decreased by swelling, but its temperature is unchanged. This behavior suggests that the-relaxation in the melt-crystallized sample originates mainly from deformation process of intermosaic block region. The swelling effect on-relaxation was also discussed.

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Zusammenfassung Quellungseffekte von Tetrachlorkohlenstoff auf das mechanische Relaxationsverhalten in Einkristall-Matten und schmelzkristallisierten Proben von linearem Polyäthylen wurden mit den Torsionspendeln untersucht. Ein sehr starkes-Maximum tritt durch die Quellung bei tieferen Temperaturen als der der-Relaxation in den nicht gequollenen Einkristall-Matten auf. Es wird gezeigt, daß diese starke-Relaxation auf das Gleiten der ausreichend gequollenen Lamellen zurückzuführen ist. Bei schmelzkristallisierten Proben wird das-Maximum durch die Quellung erniedrigt, seine Temperaturlage wird jedoch nicht verändert. Dies zeigt, daß die-Relaxation in der schmelzkristallisierten Probe hauptsäcblich auf Deformations-Prozessen in den Blöcken beruht. Auch die Quellungseffekte auf die-Relaxationen wurden diskutiert.

     

Molecular modeling of a putative antagonist binding site on helix III of the β-adrenoceptor

Summary In recent biochemical studies it was demonstrated that residue Asp¹¹³ of the-adrenoceptor (-AR) is an indispensable amino acid for the binding of-AR antagonists. Earlier fluorescence studies showed that a tryptophan-rich region of the-AR is involved in the binding of propranolol, the prototype-AR antagonist. Bearing these two biochemical findings in mind, we explored the-AR part containing Asp¹¹³, for an energetically favorable antagonist binding site. This was done by performing molecular docking studies with the antagonist propranolol and a specific-AR peptide which included, besides Asp¹¹³, two possibly relevant tryptophan residues. In the docking calculations, the propranolol molecule was allowed to vary all its internal torsional angles. The receptor peptide was kept in an-helix conformation, while side chains relevant to ligand binding were flexible to enable optimal adaptations to the ligand's binding conformation. By means of force-field calculations the total energy was minimized, consisting of the intramolecular energies of both ligand and receptor peptide, and the intermolecular energy. We found an antagonist binding site, consisting of amino acids Asp¹¹³ and Trp¹⁰⁹, which enabled energetically favorable interactions with the receptor-binding groups of propranolol. According to these results, binding involves three main interaction points: (i) a reinforced ionic bond; (ii) a hydrogen bond; and (iii) a hydrophobic/charge transfer interaction. The deduced binding site shows a difference in affinity between the levo- and dextrorotatory isomers of propranolol caused by a difference in ability to form a hydrogen bond, which is in conformity with the experimentally observed stereoselectivity. Moreover, it also provides an explanation for the ₁-selectivity ofp-phenyl substituted phenoxypropanolamines like betaxolol. Thep-phenyl substituent of betaxolol was shown to be sterically hindered upon binding to the ₂-AR peptide, whereas this hindrance is very likely to be much less with the ₁-AR peptide. Finally, the proposed antagonist binding site is discussed in the light of some recent biochemical findings and theories.Abbreviations -AR -adrenergic receptor - cDNA complementary DNA - H-bond hydrogen bond - VdW van der Waals - QSAR quantitative structure-activity relationship - ¹²⁵I-pBABC p-(bromoacetamido)benzyl-1-[¹²⁵I]iodocarazol     

Secondary metabolites of Astragalus danicus Retz. and A. inopinatus Boriss.

The chemical composition of the above-ground parts of Astragalus danicus and A. inopinatus collected in the Baikal region (Eastern Siberia) was studied for the first time. From A. danicus, pentacyclic triterpene saponins were isolated and identified, viz., 3-O-(-glucuronopyranosyl)-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-d-xylopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-d-glucopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-l-rhamnopyranosyl)-(12)-O-(-d-xylopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-l-rhamnopyranosyl)-(12)-O-(-d-glucopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-methyl-d-chiro-inositol, and linolenic acid. In A. inopinatus, the same saponins were identified as well as tricosan-1-ol and tetracosan-1-ol, 5,7,4"-trihydroxyflavon (apigenin), and a tetracyclic triterpenoid, 20(R),24(S)-epoxycyclolanost-9(11)-ene-3,6,16,25-tetrol (cycloastragenol). All reported compounds from the both genus of Astragalus were isolated for the first time. Methanolic extracts of A. danicusand A. inopinatus exhibited low inhibitory activity with respect to the growth of HeLa cells. The chloroform fraction of A. danicus showed a strong antimicrobial activity against Staphylococcus aureus and a strong cytotoxic activity against HeLa cells.     

Structure and hyperfine coupling constants of radicals in muon-irradiated single-crystal naphthalene

We have observed muonated cyclohexadienyl-type radicals in a naphthalene single crystal, using the standard transverse-fieldSR technique. Two types of radicals were found, corresponding to muonium addition at the and positions. Owing to the crystal field, the isotropic hyperfine coupling constants show large shifts from the solution values, and there is significant anisotropy in the hyperfine tensors. The results for the radicals are similar to those observed for protonated-hydronaphthyl radicals, but isotope effects are evident. The radicals, whose protonated analogues have not been fully studied, show a more pronounced localized character. Based on the hyperfine tensor directions and geometrical considerations, we have assigned each radical to a specific muon site within the crystal.     

Hydrogen adsorption on chromia-supported iridium catalyst

Effect of thermal pretreatment of chromia-supported iridium catalyst on hydrogen adsorption was studied. It was found that the hydrogen uptake by Ir/Cr₂O₃ was highly dependent on the reduction temperature. The catalyst proved to be resistant to sintering in oxygen atmosphere at temperatures up to 700 °C and it showed symptoms of redispersion even at 650 °C.

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. Ir/Cr₂O₃ . 700°C, , 650°C .

     

Secondary structure of peptides 16th. Characterization of proteins by means of13C NMR CP/MAS spectroscopy

50.3 or 75.4 MHz¹³C NMR cross-polarization/magic angle spinning spectra of human hair, horse hair, horse hoof, parrot feather, sperm whale myoglobin, and horse heart cytochrome C were measured. The spectra of human hair and horse hair indicate nearly equal mole fractions of-sheets and-helices and a low percentage of amorphous regions, whereas horse hoof contains a higher fraction of amorphous proteins. The parrot feathers contain a small-helix fraction (ca. 10±5 %) in additon to a large-sheet fraction whereas cytochrome C contains 70–90%-helices. The spectrum of myoglobin could not interpreted in terms of defined secondary structures. The usefulness of the¹³C NMR CP/MAS spectroscopy for the characterization of proteins is compared with that of IR spectroscopy and X-ray diffraction.     

Thermal Expansion of Mixed Zirconium Phosphates

A series of framework phosphates with varied ratio of cations Na_5-2x B _x ^IIZr(PO₄)₃, B^II = Mg, Ca, Sr, Ba (0 x 2) and Na_5-3x Fe _x Zr(PO₄)₃ (0 x 1.33) were synthesized and studied under heating. The coefficients of thermal expansion along crystal axes _a and _c were calculated, and their dependences on the cationic composition (nature and concentration) and on the occupancy of out-of-framework structural positions were established.     

Effect of cross-conjugation on properties of α-mercurated carbonyl compounds

Conclusions The polarographic data and the data of the IR spectra of the-mercurated esters of the cinnamic and crotonic acids show that in these compounds the- conjugation of the C-Hg bond with the C=O group is weakly expressed, and may be completely absent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1912–1913, August, 1973.     

Chemical peculiarities and structure of 2-(indane-1′, 3′-dionid-2′-yl)pyridinium (α-pyrophthalone)

The fine structure of 2-(indane-1,3-dionid-2-yl)pyridinium (-pyrophthalone) was determined by PMR spectroscopy and x-ray diffraction analysis. The -pyrophthalone molecule is almost planar; the dihedral angle between the pyridine ring and the indanedione ring is 5°. The structure is stabilized by an intramolecular hydrogen bond with a length of 2.73 Å. The molecules are packed in the crystal at van der Waals distances similar to those in molecular self-complexes. The data obtained for -pyrophthalone confirm a dipolar ion structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1076–1080, August, 1978.     

13C NMR spectra and stereoisomerism in series of androstano-and estrano-D′-pentaranes

Conclusions The stereoisomerism in series of androstano- and estrano-D-pentaranes in solution has been investigated by¹³C NMR. The orientation of the D ring in the 15,16-, 15,16-, and 15,16-isomers relative to the steroid skeleton, as well as the boat conformation of the D ring, were determined from the¹³C chemical shifts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1038–1045, May, 1984.     

The polystyrene affinity of methylglycosides,deoxysugars and glucooligosaccharides

The partition coefficients K _av of methylglycopyranosides, deoxysugars and glucooligosaccharides for partition between polystyrene gel and aqueous solvent systems were determined. Each group of sugars showed widely different polystyrene affinities and these affinities increased markedly in NaCl solution but were eliminated in 50% methanol. The K _av for methyl-D-mannoside (10.6) was remarkably greater than those of methyl--D-glucoside (3.0) and methyl--D-galactoside (2.2). Another notable feature was that the polystyrene affinity was affected by the position of the OH-H substitutions in deoxysugars and by the type of the glucosidic linkages of glucodisaccharides. The inspection of the overall K _av spectrum together with the accessible surface data of sugar molecules suggests that the hydrophobicity of sugars is determined by a set of several factors including CH-surface area, hydration effect of OH groups and molecular planarity and rigidity.     

Necrosaminreihe, 5. Mitt.: Über eine einfache Synthese von aliphatischen α-Diaminen

Zusammenfassung Es wird eine Reaktionsfolge beschrieben, die eine einfache Darstellung der langkettigen -Diamine erlaubt. Die Synthese wird an Beispielen des 2,3-Diamino-tridecans (7 a), 2,3-Diamino-nonadecans (7b) und 4,5-Diamino-eicosans (14) geprüft. -Aminosäuren und Carbonsäureanhydride werden mittels derDakin-West-Reaktion in die -Acylamidoketone übergeführt.7a und7b werden über die Stufen -Acetamidoketon (4), -Aminoketon (5), Oxim (6) und dessen Reduktion mit Lithiumaluminiumhydrid gewonnen.14 wird über die Stufen 2-Benzoylaminomargarinsäure (10), 5-Benzoylamino-eicosanon-(40 (11), 5-Benzoylaminoeicosanon-(4)-oxim (12) und 4-Amino-5-benzylamino-eicosan (13) dargestellt.

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A simple synthesis of long-chain -diamines is described. The method is illustrated by the preparation of 2,3-diaminotridecane (7a), 2,3-diaminononadecane (7b) and 4,5-diaminoeicosane (14). In the first reaction step -amino acids and carboxylic acid anhydrides are converted into -acylamido ketones by means of theDakin-West reaction. Both7 a and7 b are prepared through the intermediates -acetamido ketone (4), -amino ketone (5) and oxime (6) followed by the reduction of the latter with lithium aluminum hydride.14 is prepared via 2-benzoylaminomargaric acid (10), 5-benzoylamino-4-eicosanone (11), 5-benzoylamino-4-eicosanone oxime (12) and 4-amino-5-benzylaminoeicosane (13).

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4. Mitt.:P. Alaupovi undM. Protenik, Croat. Chem. Acta28, 225 (195).     

Transformed steroids. 121. Synthesis of the δ-lactone of 3β-acetoxy-16α-hydroxy-6-oxo-24-nor-5α-chol-17(20)-en-23-oic acid

The synthesis of the ¹⁷⁽²⁰⁾-16 analog of natural chiogralactone is described. Attempts to introduce a 6-oxo group directly into the -lactone proved unsuccessful, since the first stage — saponification — took place with the formation of three products: the 3-hydroxy--lactone, the 3-hydroxy-²⁰⁽²²⁾-lactone, and the 15,17(20)-dienoic acid. The synthesis of the desired compound was effected from the ethyl ester of the 5,16-dienoic acid by the scheme 3-acetate3-tosylate6-hydroxy-3,5-cyclosteroid6-oxo-3,5-cyclosteroid6-oxo-5H--lactone. It has been shown that the cyclopropane ring in the 3,5-cyclosteroid -lactone is extremely stable under the conditions of acid treatments.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 184–187, March–April, 1981.     

Biosynthesis of asterosaponins from cholesterol and other sterols under the conditions ofin vitro homogenates of starfish gonads and pyloric ceca

Conditions have been selected for performing thein vitro biosynthesis of asterosaponins from cholesterol and other sterols in homogenates and cultures of the gonads and pyloric ceca of Far Eastern starfish. It has been shown that the aglycone moiety of an asterosaponin can be biosynthesized from cholesterol, cholesterol sulfate, 5-cholestanol, and 3,6-dihydroxy-5-cholestane but not from 3, 6-dihydroxy-5-cholestane. Of the give precursors studied, cholesterol was transformed into asterosaponins most completely.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 663–667, September–October, 1985.     

A study of nitrogen- and sulfur-containing heterocycles

The catalytic hydrogenation of N--cyanoacylureas and 1-alkyl-3--cyanoacylureas in the presence of hydrochlorides of aromatic amines has given N--arylaminoacryloyl-, 1-alkyl-3--arylaminoacryloyl-, N--alkyl--arylaminoacryloyl-, and 1-alkyl-3--alkyl--arylaminoacryloylureas. The action of N- -phenylaminoacryloyl- and 1-methyl -3- -phenylaminoacryloylureas of ethanolic hydrogen chloride has given uracil and 1-methyluracil.For Communication IX, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 6, pp. 847–850, June, 1970.     

The thermoanalytical determination of deactivation types of cation-exchanger catalyst's

The dependence of the thermal decomposition of a cation-exchanger catalyst on its deactivation type has been ascertained, and thermal analysis has been suggested as a diagnostic method for the determination of the condition of such a catalyst.

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Zusammenfassung Die Abhängigkeit der thermischen Zersetzung eines Kationaustauscher-Katalysators von seinem Inaktivierungstyp wurde bewiesen und die Thermoanalyse als diagnostische Methods für die Bestimmung des Zustandes eines solchen Katalysators vorgeschlagen.

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. , .

     

Verfolgung der Verbrennungsreaktionen Exothermer Massen auf Basis von Aluminium,Fluoriden und Natriumverbindungen mit Differenzialthermoanalyse

Zusammenfassung Das Verbrennen von Mischungen der exothermen Systeme Al-NaF-NaNO₃ und Al-CaF₂-NaNO₃ wurde durch Röntgenanalyse ergänzte DTA untersucht. Um den Einfluß des durch Dissoziation von NaNO₃ gebildeten Sauerstoffs zu bestimmen wurden auch Mischungen, welche anstatt NaNO₃ NaNO₂ oder Na₂O₂ enthielten, geprüft.Zwei, bei 310° bzw. 850° einsetzende exotherme Reaktionen wurden in den Gemischen vom Typ Al-NaF-NaNO₃ gefunden. Die erste ist der Dissoziation von NaNO₃ zuzuschreiben, die zweite ist der Anwesenheit von Luft zuzuordnen.Beide exothermen Reaktionen wurden im System Al-CaF₂-NaNO₃ in Richtung höherer Temperaturen verschoben. Die Untersuchung der NaNO₂- oder Na₂O₂-haltigen Gemische anstatt NaNO₃ zeigte, daß die Dissoziation von NaNO₃ den zum Verbrennen benötigten Sauerstoff liefert, andererseits würde letztere Reaktion sonst nur in begrenztem Ausmaß stattfinden.

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Combustion of exothermic mixtures belonging to the system Al-NaF-NaNO₃ and Al-CaF₂-NaNO₃ was investigated by DTA and X-ray analysis. In order to determine the influence of the oxygen generated by dissociation of NaNO₃, the mixtures containing NaNO₂ or Na₂O₂ instead of NaNO₃ were also examined.Two exothermic reactions starting at 310° and 850° rsp. were found in the mixtures of the Al-NaF-NaNO₃ type. The first is due to the dissociation of NaNO₃ and the second proceeds independence of the availability of air.Both exothermic reactions were shifted to higher temperatures in the system Al-CaF₂-NaNO₃. Investigation of the mixtures containing NaNO₂ or Na₂O₂ instead of NaNO₃ has proved that the dissociation of NaNO₃ supplies the oxygen required for combustion which should otherwise proceed only in a limited extent.

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Résumé On a étudié, par ATD et par analyse aux rayons X, la combustion des mélanges exothermiques appartenant aux systèmes Al-NaF-NaNO₃ et Al-CaF₂-NaNO₃. Afin de déterminer l'influence de l'oxygène engendré par la dissociation de NaNO₃, on a étudié de même des mélanges contenant NaNO₂ ou Na₂O₂ au lieu de NaNO₃.On a trouvé, dans les mélanges du type Al-NaF-NaNO₃, des réactions exothermiques à partir des temperatures respectives de 310° et 850°. La première est due à la dissociation de NaNO₃ et la seconde dépend de l'air disponible.Dans le système Al-CaF₂-NaNO₃ les deux réactions sont déplacées vers les températures plus élevées. L'examen de mélanges contenant NaNO₂ ou Na₂O₂ au lieu de NaNO₃ à montré que c'est la dissociation de NaNO₃ qui fournit l'oxygène nécessaire pour la combustion. Celleci n'aurait lieu, autrement, que d'une manière limitée.

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, l-NaF-NaNO₃ Al-CaF₂-NaNO₃. , NaNO₃, , NaNO₃, , NaNO₂ Na₂. , Al-NaF-NaNO₃ , 310° 850°. , . Al-CaF₂-NaNO₃ . , NaNO₂ Na₂O₂, , , , , .

     

Binding energy of oxygen to the surface of promoted V?Mo?O catalysts for acrolein oxidation to acrylic acid

It has been established that P, Cs and Cu additives to V–Mo–O catalysts affect essentially both binding energy of surface oxygen and mobility of bulk oxygen.

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P, Cs Cu V–Mo–O .

     

Thermal decomposition of Cu(I) phosphine complexes

The thermal decomposition of Cu(I) phosphine complexes of the general types (CuXPPh₃)₄, [CuX(PPh₃)₂] and [CuX(PPh₃)₃] was investigated.The thermal decomposition of (CuXPPh₃)₄, where X denotes Cl^–, Br^–, I^–, NO ₃ ^– and PPh₃=P(C₆H₅)₃, occurs with formation of a phosphine oxide intermediate. For the remaining complexes this intermediate was not proved in the thermal decomposition.

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Zusammenfassung Die thermische Zersetzung der Cu(I)-Phosphinkomplexe vom allgemeinen Typ (CuXPPh₃)₄ und [CuX(PPh₃)₂], wie auch [CuX(PPh₃)₃] wurde untersucht. Die thermische Zersetzung von (CuXPPh₃)₄, wobei X=Cl^–, Br^–, I^– und NO ₃ ^– bedeutet und PPh₃=P(C₆H₅)₃, verläuft unter Bildung eines Phosphinoxid Zwischenproduktes, bei den übrigen Komplexen konnte dieses im Laufe der thermischen Zersetzung nicht nachgewiesen werden.

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Résumé On a étudié la décomposition thermique des complexes phosphine-Cu(I) de formule générale (CuXPPh₃)₄, [CuX(PPh₃)₂], [CuX(PPh₃)₃]. La décomposition thermique de (CuXPPh₃)₄, où X désigne Cl^–, Br^–, I^– et NO ₃ ^– , et PPh₃=P(C₆H₅)₃, s'effectue avec formation d'un oxyde de phosphine intermédiaire; avec les autres complexes, cet intermédiaire n'a pas été mis en évidence au cours de la décomposition thermique.

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(CuXPPb₃)₄ [CuX(PPh₃)₂] [CuX(PPh₃)₃]. (CuXPPh₃)₄, X=Cl^–, Br^–, I^–, NO ₃ ^– , PPh₃=(₆₅)₃ . .

     

Reaction scheme in the non-isothermal decomposition of (C6H5NH3)4Mo8O26 · 2 H2O

The thermogravimetric decomposition of anilinum octamolybdate has been studied under non-isothermal conditions to elucidate the chemical reactions taking place in the first step of decomposition of the anhydrous compound.The decomposition products were analyzed by gas-liquid chromatography, gas chromatography-mass spectrometry (GC/MS), infrared spectroscopy and X-ray powder diffraction.The main decomposition product of aniline turned out to be indole, which is different from the major product in the isothermal decomposition at the same temperature, i.e. N-ethyl-aniline.A dehydrocyclization reaction is suggested as the rate-dependent process. This is probably due to the catalytic effect of the octamolybdate anion.

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Zusammenfassung Die thermische Zersetzung von Anilinoctamolybdat wurde unter nicht-isothermen Bedingungen thermogravimetrisch untersucht, um die im ersten Zersetzungsschritt der wasserfreien Verbindung verlaufenden chemischen Reaktionen aufzuklären. Die Zersetzungsprodukte wurden mittels Gas-Flüssigkeits-Chromatographie, Gaschromatographie-Massenspektrometrie (GC/MS), Infrarotspektroskopie und Röntgendiffraktometrie analysiert. Als Hauptprodukt der Zersetzung von Anilin wurde Indol gefunden, während bei isothermer Zersetzung bei gleicher Temperatur vorwiegend N-Äthylanilin entsteht. Es wird angenommen, daß beim nicht-isothermen Prozeß eine wahrscheinlich durch das Octamolybdat katalysierte Dehydrocyclisierungsreaktion verläuft.

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, . - , -- , . , -N- . , , -.