Etude de la microstructure des oligomeres desactives du butadiene-1,3

Oligomers of butadiene have been prepared in hydrocarbons in the presence of butyllithium isomers. Nuclear magnetic resonance (NMR), gas chromatography and i.r. spectroscopy allowed the study of the microstructures of the products. Various parameters (nature of the deactivator, the solvent and the initiator as well as the monomer/initiator ratio) influence the microstructure. All the results may be explained on the basis of delocalized living species in anionic polymerization of conjugated dienes.     

Rohrleitungen aus Glas

Ohne ZusammenfassungDer Text erscheint ausführlich in Die Chemische Fabrik, 1938, Heft 49/50. — Dieser Vortrag trat an die Stelle des von Dr. G. Schott angemeldeten Vortrages: Technische Anwendung von Jenaer Glas in der chemischen Industrie.     

Zwei neue pentacyclische dimere des cycloheptatriens

Titanium - catalyzed dimerization of cycloheptatriene affords pentacyclo[7.5.0.0^2,8.0^5,14.0^7,11]tetradeca-3,12-diene, $\text{3}$, and pentacyclo[8.4.0.0^3,7.0^4,14.0^6,11]tetradeca-8,12-diene, $\text{4}$. By heating, $\text{3}$ is converted quantitatively into $\text{4}$.     

THE PHOTOMORPHOGENETIC CONTROL OF THE DEVELOPMENT OF PLASTID GLYCERALDEHYDE-PHOSPHATE DEHYDROGENASE AND PHOSPHORIBULOKINASE ACTIVITIES IN COTYLEDONS OF MUSTARD SEEDLINGS

The plastid glyceraldehyde-phosphate dehydrogenase and phosphoribulokinase of mustard cotyledon extracts were activated by preincubation with ATP and with ATP and dithiothreitol respectively. By in vitro activation prior to assay, it was possible to determine the potential activities, which appear to have been directly proportional to the amount of each enzyme protein present. In this way it was possible to deduce the net synthesis of these two enzymes. The induction of synthesis of glyceraldehyde-phosphate dehydrogenase and phosphoribulokinase, by continuous far red or white light were similar hut net synthesis in continuous far red continued longer for glyceraldehyde-phosphate dehydrogenase than for phosphoribulokinase. The kinetics of the development of the glyceraldehyde-phosphate dehydrogenase potential activity were very close to those reported by Bruning et al. (1975) for this enzyme. The data do not permit elimination of either the single switch or multiple switches hypotheses for the action of phytochrome. Continuous white illumination gave results similar to those for continous far red for the net synthesis of the two enzymes but it was more effective than far-red in bringing about enzyme activation in vivo.     

Über Fluoride des zweiwertigen Eisens: Ba2[Fe3F10]

On the Knowledge of Ba₂[Fe₃F₁₀] For the first time colourless single crystals of Ba₂Fe₃F₁₀ have been prepared by reduction of a mixture of 3 BaF₂/7 FeF₃ in a Fe-tube (reaction with the wall 750°C, 60 d). Ba₂Fe₃F₁₀ crystallizes in the monoclinic spcgr. P2₁/c with a = 788.3(1), b = 623.0(1), c = 1868.0(3) pm, β = 111.79(1)º, Z = 4. (Fourcircle diffractometer PW 1100, Fa. Philips, MoKα, 2383 of 2383 I₀(hkl), R = 8.1%, R_w = 4.1%, parameters see in the text). The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Post-column reaction detection of biotin in human plasma ultrafiltrate based on laser-induced fluorescence energy transfer in the far-red spectral region

High performance liquid chromatography followed by post-column reaction detection in the far-red spectral region provides added sensitivity and selectivity. A homogeneous fluorescence energy transfer assay in the competitive mode based on the binding of biotin and streptavidin was developed as an on-line post-column reaction detection system. The labels used for energy transfer were R-Phycoerythrin conjugated to biotin and Cyanine 5 labeled with streptavidin. The energy transfer peak was measured at 670 nm and excitation was achieved using the 488 nm line of an argon ion laser. The biotin concentration in plasma ultrafiltrate ranged from 0.024 to 6.12 ng/mL (n = 6). The precision of the two controls, 0.24 and 2. 44 ng/mL, was found to be 18.70% and 9.92% relative standard deviation respectively. Accuracy was 10.47% and 1.95% difference from spiked, respectively (n = 6). The limit of detection was 21.70 pg/mL (8.90 x 10(-11)M) calculated based on a factor of 2x the standard deviation of the blank (n = 6). The correlation coefficient for the calibration curve was found to be 0.9995. Recovery from plasma ultrafiltrate at 2.44 ng/mL was 103.40% (n = 6). Detection selectivity was indicated by the absence of background fluorescence in six different plasma samples collected from six individual donors. Endogenous levels were detected in two of the six pools of plasma ultrafiltrates.     

Use of reference pools to compare the qualitative and quantitative determination of polychlorinated biphenyls by packed and capillary gas chromatography with electron capture detection. Part 1. Serum

Serum for reference pools of in vivo polychlorinated biphenyls (PCBs) was obtained from four goats that had received one dose (100 mg kg-1) of a selected technical Aroclor (AR) (1016, 1242, 1254 or 1260) and were allowed to recover for 30 d. These pools were used to assess the differences in an analytical method that determines and quantifies PCBs using packed-column gas chromatography (PCGC) (quantified on the basis of mean mass percent. data for grouped PCB peaks) and capillary-column gas chromatography (CCGC) (quantified on the basis of percent. composition data for specific congeners). With CCGC, results were statistically significantly different (p less than or equal to 0.0002) from results with PCGC for ARs 1016, 1242 and 1254 but not for AR 1260 (p = 0.23). When comparing these gas chromatographic methods using bovine serum spiked in vitro with the same ARs at 17-25 p.p.b., it was found that the methods were not statistically significantly different for any of the ARs (p = 0.30-0.92). Levels of serum PCB determined by the two methods for 12 persons, divided into two groups according to exposure, were compared using the paired t-test. Group 1 consisted of three persons with dietary and/or environmental exposure; one with dietary and/or environmental exposure in addition to occupational exposure dating back 20 years. Group 2 consisted of eight persons with recent occupational exposure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Study of the formation of β-lial alloy by electrochemical techniques in molten LiCl+KCl

The formation of β-LiAl during electrochemical incorporation of lithium into α-LiAl alloy from molten LiCl+KCl was investigated by chronoamperometric and chronopotentiometric techniques. It is shown that at the very beginning of the lithium incorporation a supersaturation of the α-phase occurs, the incorporation being controlled by the metal diffusion in the β-phase.The initial stages of formation of β-LiAl are explained in terms of a model involving nucleation and three-dimensional growth. In contrast with the model for conventional electrolytical metal deposition the process is controlled in the first moment by the lithium/aluminium interdiffusion in the growing β-nuclei. However according to the high value of the interdiffusion coefficient the process is rapidly limited by the ohmic resistance of the circuit.     

Spectrophotometric determination of the protolytic dissociation constants of the new chromogenic reagent "palladiazo"-I Investigations with sodium hydroxide, perchloric acid and different aqueous buffer solutions

The "palladiazo" reagent has been subjected to a detailed spectrophotometric investigation in concentrated perchloric acid, different aqueous buffers and concentrated sodium hydroxide solutions. K(1)-K(10) and (1)-(10) values corresponding to the instability constants of the protolytic equilibria involved and to the molar absorptivities at 540 and 630 run of the different proton complex species of the system have been calculated by a number of analytical and graphical spectrophotometric methods. Special attention has been paid to the study of the complicated phenomena implied by the interaction of the reagent with perchloric acid, which has been shown to give rise to alteration of the initial isomeric composition of the reagent and to the formation of addition and/or oxidation products derived from side-reactions undergone by the reagent with the medium. All the instability constants and molar absorptivities, which have been determined by several methods, are tabulated for comparison.     

Behavior of acridine toward sodium amide and alkali

Acridine undergoes the Chichibabin reaction with difficulty in dimethylaniline or xylene at temperatures up to 150–160°, but a mixture of 9-aminoacridine and diacridanyl, with predominance of the latter, is formed at higher temperatures. Fusion of acridine with alkali at 300–350° gives acridone in 28% yield.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1673–1675, December, 1972.