Bis(phenanthroline)-ethylenediamine conjugate displays excimer fluorescence upon binding with DNA

1,2-Bis(1,10-phenanthrolin-2-yl)ethylenediamine (1) displays a unique long-life time excimer fluorescence at 528 nm by binding with calf thymus DNA, while its monomer fluorescence at 400 nm shows a decrease upon binding with DNA.     

Pressure-induced hexagonal phase in a ternary microemulsion system composed of a nonionic surfactant, water, and oil

The pressure-induced phase transition in a microemulsion, consisting of pentaethylene glycol mono-n-dodecyl ether, water, and n-octane, was investigated by means of small-angle neutron scattering. A pressure-induced phase transition from a lamellar structure to a hexagonal structure was observed. The temperature-pressure phase boundary shows a positive slope with dTdP approximately 0.09 KMPa. The structure unit of the high-pressure hexagonal phase was an oil-in-water cylinder with the membrane thickness of 15.5 A, identical to the low-temperature hexagonal phase. Pressurizing was found to have the same effect by decreasing temperature. This behavior was satisfactorily explained with the pressure dependence of the spontaneous curvature of surfactant membranes. That is, the volume change of surfactant tails plays a dominant role in the structure change of the microemulsion with applying pressure.     

Intramolecular excimer of DI(1-pyrenylmethyleneoxycarbonyl) alkanes

Intramolecular excimer emission of a series of di(1-pyrenylmethyleneoxycarbonyl)alkanes (n = 0–22) has been studied under photostationary conditions. The intramolecular excimer formation rate constant decreases monotonously with increasing number of methylene units of the chains in the low temperature region. The temperature dependence of the rate constant for each sample was studied to give an apparent activation energy of ca. 5 kcal/mol.     

Studies on preparation and stability of styrene-methyl methacrylate and styrene -methacrylic acid copolymer latices

Summary Series of styrene-methyl methacrylate (SM) and styrene-methacrylic acid (SA) copolymer latices have been prepared by emulsion polymerization using polyoxyethylene nonyl phenyl ether as emulsifier and potassium persulphate as initiator. Trace carboxyl groups were detected both in polystyrene latex and styrene-methyl methacrylate copolymer latices. The stability and electrophoretic behaviour of these latices against barium chloride have been investigated. The values of the critical coagulation concentration (c. c. c.) increased with increasing methacrylic acid content for SA series latices, while they are almost independent of methyl methacrylate content for SM series latices. The effects of methyl methacrylate and methacrylic acid on the change in Hamaker constant were found to be almost identical. The difference inc. c. c. between SM and SA series latices seems to be due to the difference in electrical repulsion caused mainly by carboxyl groups on the surface.

---

Zusammenfassung Eine Serie der Styrol-Methyl-Methacrylat (SM) und Styrol-Methacrylsäure (SA) Mischpolymer-Latices wurde unter Verwendung von Polyoxyäthylennonylphenyläther als oberflächenaktives Agents und Kaliumpersulfat als Initiator von Emulsionspolymerisation hergestellt. Wenige Carboxylgruppen in beiden Polystyrol-Latex-und Styrol-Methyl-Methacrylat-Mischpolymer-Latices wurden gefunden. Stabilität und elektrophoretische Beweglichkeit dieser Latices gegen Bariumchlorid würden untersucht. Die Werte der kritischen Koagulaiionskonzentration (k. k. k.) nahm mit Zunahme des Gehaltes an Methacrylsäure für SA-Latices zu, während sie fast unabhängig vom Gehalt an Methyl-Methycrylat für SM-Latices sind. Die Wirkungen des Methyl-Methacrylats und der Methacrylsäure auf die Änderung der Hamaker Konstante sind meistens identisch. Der Unterschied in k. k. k. zwischen SM- und SA-Latices scheint hauptsächlich auf den Unterschied in der elektrischen Abstoß durch Carboxylgruppen auf der Oberfläche zuzückgeführt werden zu können.

---

---

With 4 figures, and 2 tables     

Effects of ruthenium hydride species on primary amine synthesis by direct amination of alcohols over a heterogeneous Ru catalyst

Heterogeneously catalysed synthesis of primary amines by direct amination of alcohols with ammonia has long been an elusive goal. In contrast to reported Ru-based catalytic systems, we report that Ru–MgO/TiO₂ acts as an effective heterogeneous catalyst for the direct amination of a variety of alcohols to primary amines at low temperatures of ca. 100 °C without the introduction of H₂ gas. The present system could be applied to a variety of alcohols and provides an efficient synthetic route for 2,5-bis(aminomethyl)furan (BAMF), an attention-getting biomonomer. The high catalytic performance can be rationalized by the reactivity tuning of Ru–H species using MgO. Spectroscopic measurements suggest that MgO enhances the reactivity of hydride species by electron donation from MgO to Ru.

Ru–MgO/TiO₂ exhibited high catalytic performance for direct amination of alcohols based on the acceleration effects of MgO.     

Evaluation of oriented lysozyme immobilized with monoclonal antibody

The orientation of a lysozyme immobilized with a monoclonal antibody was evaluated based on determination of the uppermost surface structure using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specific peaks of the oriented lysozyme immobilized with monoclonal anti-lysozyme antibody were obtained in comparison with reference samples, non-oriented immobilized lysozyme and immobilized anti-lysozyme antibody. All samples were freeze-dried before TOF-SIMS measurement, and then each sample was measured using TOF-SIMS with a bismuth cluster ion source. TOF-SIMS spectra were analyzed to select peaks specific to the oriented immobilized lysozyme as well as to identify their chemical formula and ensemble of amino acids. The possible chemical formulae of the lysozyme fragments were then investigated with an element matching program and a residue matching program. The results from TOF-SIMS spectra analysis were compared to the amino acid sequence of the lysozyme and its three-dimensional structure registered in the protein data bank. Finally, the fragment-ion-generating regions of the oriented immobilized lysozyme were determined based on the suggested residues and the three-dimensional structure.     

Polymerisation von Methyl- und ?thylmethacrylaten mit Alkalimetall-Alkoxidderivaten des Poly?thylenoxids

Ohne Zusammenfassung