Poly-β-hydroxybutyrate Production by Fast-Growing Rhizobia Cultivated in Sludge and in Industrial Wastewater

In our study, the potential of producing polyhydroxybutyrate (PHB) by cultivating fast-growing rhizobia (Sinorhizobium meliloti, Rhizobium leguminosarum bv. viciae, R. leguminosarum bv. phaseoli and R. leguminosarum bv. trifolii) in sludge and in industrial wastewater was evaluated. Results confirmed the possibility of using sludge as media for rhizobial growth. During growth, substantial quantity of PHB was accumulated and yields varied depending on the media and rhizobial species. Growing in sludge, PHB production did not exceed 3.7% w/w for all strains at the end of experiment (after 72 h). During the growth of S. meliloti, PHB yield varied and the maximum value reached 7.27% w/w after 60 h, with 1% Total Suspend Solid (TSS) sludge. Alkaline sludge pre-treatment affects rhizobial growth but did not improve the PHB accumulation. While growing S. meliloti in industrial wastewater, the PHB yields varied and the highest value was obtained with slaughterhouse wastewater (10.7% w/w) after 35 h of growth. Therefore, this work shows the potential of exploiting PHB production by rhizobia growing in wastewater or sludge which could be applied to bioplastic industry, and confirms the potential of these recyclable wastes for high production of rhizobial cells useable for legumes inoculants production. This study provides an environmentally sound way of sludge and wastewater management and use in diverse biotechnological applications.     

Observation of non-Förster-type energy-transfer behavior in quantum dot-phthalocyanine conjugates

The effect of linker chain length on the energy transfer from CdSe quantum dots (QDs) to silicon phthalocyanine (Pc) photodynamic therapy agents was investigated by steady-state and femtosecond time-resolved spectroscopy with 500 nm light for the specific excitation of the QD energy donor. The conjugation between the QD and the Pc was achieved with linker chains varying from 4 to 9 bond lengths by incorporating 1-6 methylene groups into the axial ligand of the Pc. With increasing chain length, the energy-transfer efficiency increased, which appears to be opposed to a purely F?rster-type resonance energy-transfer behavior that is commonly discussed for the energy transfer in QD conjugates. The obtained results provide strong evidence for a capping-layer-mediated energy transfer in the QD-based donor-acceptor conjugates.     

Spectrophotometric determination of trace level thorium with n-phenylbenzohydroxamic acid

A method for the determination of thorium(IV) based on thorium-PBHA complex, which is extracted into amyl alcohol, is described. The thorium is back-extracted from amyl alcohol with 0.2M hydrochloric acid and estimated spectrophotometrically with thorin. The system has a maximum absorbance at 545 nm and obeys Beer's law between 0.5 to 12.5 ppm and the molar absorption coefficients is 1.7·10 1·mol^?1·cm^?1., Various parameters for the extraction and back-extraction and the effect of diverse ions have been studied.     

Photometric determination of barium and calcium in lubricating oils and lubricating oil concentrates

Summary A rapid and sensitive method for the determination of barium and calcium in lubricating oils is described. It is based on the formation of barium chromate and calcium oxalate and the estimation of barium and calcium by determining chromium and oxalate ions. Results obtained are in close agreement with those obtained by the Standard IP Method.

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Photometrische Barium- und Calciumbestimmung in Schmierölen und Schmierölkonzentraten

Zusammenfassung Die schnelle und empfindliche Methode beruht auf der Fällung der Elemente als Chromat bzw. Oxalat und der photometrischen Bestimmung des Chromats aus der Farbe seiner Lösung und des Oxalats durch Reaktion mit Permanganat. Die Analysenergebnisse stimmen gut mit denen nach der Standardmethode des Institute of Petroleum überein.

     

Vibrational Dynamics and Heat Capacity of Trans‐1,4‐Polyisoprene (α‐Form)

Vibrational dynamics of the α‐polymorphic form of trans‐1‐4‐polyisoprene is described using Higg's method and the Urey‐Bradley force field. Characteristic features of dispersion profiles such as repulsion and bunching are reported. A comparison with the β‐form is presented and possible reasons for variation in heat capacity are discussed.