Action mechanism of water soluble ethanol on phospholipid monolayers using a quartz crystal oscillator

Interaction between phospholipid monolayers (dihexadecyl phosphate: DHP, dipalmitoyl phosphatidyl choline: DPPC) and water soluble ethanol has been studied using quartz crystal microbalance (QCM) method and quartz crystal impedance (QCI) method. The quartz crystal oscillator was attached horizontally on the DHP and DPPC monolayers that were formed on the water surface. At low concentration, increased ethanol concentration decreased the frequency for QCM and increased the resistance for QCI. Both frequency and resistance approached asymptotically to a saturation value. A further increase in ethanol concentration induced a sudden and discontinuous linear change (a decrease in frequency and an increase in resistance). Based on these results, we propose the following action mechanism of ethanol on phospholipid monolayers: at low concentration, the ethanol hydrates adsorb into the monolayer/water interface and saturate on the interface. The monolayer viscosity also increases with the adsorption of hydrates. A further increase in concentration causes multilayer formation of hydrates and/or penetration of hydrates into the monolayer core. The viscosity of the interfacial layer (monolayer and interfacial structured water) changes dramatically according to the action of ethanol hydrates.     

On the Mourre estimates for Floquet Hamiltonians

Letters in Mathematical Physics - In the spectral and scattering theory for a Schrödinger operator with a time-periodic potential $$H(t)=p^2/2+V(t,x)$$ , the Floquet Hamiltonian $$K=-i\partial...     

Gelfand-Zetlin basis for Uq(gl(N+1)) modules

The Gelfand-Zetlin basis of U_q(gl(N+1)) modules is constructed via the lowering operator method.     

Studies on oxygen determination in organic microanalysis. II. On the microanalysis of oxygen by decrease in the quantity of anhydro-iodic acid

Summary Oxygen in organic compounds is determined by means of the decrease in weight of anhydro-iodic acid. Anhydro-iodic acid is stable in air and can be used for a long time. Satisfactory analyses are obtained.

---

Zusammenfassung Sauerstoff kann in organischen Verbindungen durch Messung des Gewichtsverlustes der Anhydrojodsäure bestimmt werden. Diese ist an der Luft beständig und bleibt lange Zeit verwendungsfähig. Zufriedenstellende Analysenergebnisse werden erhalten.

---

Résumé Le dosage de l'oxygène dans les composés organiques est effectué par la détermination de la diminution de poids de l'acide anhydroiodique. L'acide anhydroiodique est stable à l'air et peut être employé pendant des temps très longs. Des résultats satisfaisants ont été obtenus par les auteurs.

     

Influence of electroless nickel plating of hydrogen-absorbing alloys on cycle characteristics of nickel-metal hydride batteries

The effects of electroless nickel plating of a hydrogen-absorbing alloy on the cycle characteristics of a nickel-metal hydride battery were investigated. The cycle life was improved by employing an electroless nickel-plated hydrogen-absorbing alloy for the negative electrode, which retained the same high-rate level and low-temperature characteristics compared to a cell using a non-plated hydrogen-absorbing alloy. The electroless nickel-plated hydrogen-absorbing alloy provided better electrochemical characteristics when its surface was partly and tightly covered by nickel particles under optimal electroless plating conditions.     

Studies on oxygen determination in organic microanalysis. I. A modified purification method of nitrogen gas

Summary Reduced copper has been used generally for removing the oxygen in the nitrogen gas in the microdetermination of oxygen, but instead of reduced copper the authors have used about 20 g of Raney-nickel in the dry state prepared through the development of Raney-alloy, and have found that the oxygen is removed completely from the nitrogen gas at room temperature; Raney-nickel has also a much greater capacity than the reduced copper.

---

Zusammenfassung Zur Reinigung des für die Mikrobestimmung des Sauerstoffs verwendeten Stickstoffs wurde üblicherweise reduziertes Kupfer verwendet. An dessen Stelle verwenden die Verfasser etwa 20 g trockenes Raney-Nickel und konnten feststellen, daß der Stickstoff damit schon bei Zimmertemperatur vollständig von Sauerstoff befreit wird. Außerdem hat Raney-Nickel eine viel höhere Kapazität als reduziertes Kupfer.

---

Résumé On emploie en général le cuivre réduit pour l'élimination de l'oxygène contenu dans l'azote lors du microdosage de l'oxygène; au lieu de ce réactif les auteurs ont employé environ 20 g de nickel de Raney, à l'état sec préparé à partir d'alliage de Raney; ils ont trouvé que l'oxygène était éliminé complètement de l'azote à la température ambiante; le nickel de Raney a également une capacité d'absorption beaucoup plus grande que le cuivre réduit.

     

Molecular chain conformation and crystallite structure of cellulose. I. Fine structure of rayon fibers

A most reasonable folded-chain model for the fine structure of rayons (cellulose II) has been developed through experimental work on a theoretical basis. All the materials uniformly gave a levelling-off DP of about 40, equivalent to a length around 200 Å, for cellulose molecule segments at the early stage of heterogeneous acid hydrolysis when the first minor fraction is scarcely dissolved. Measurements by small-angle and wide-angle x-ray scattering put the crystallite length from various rayon fibers at about 200 Å, without exception. A family of GPC chromatograms, furthermore, on the hydrolyzed cellulose exhibited a single peak considered to represent monodispersed materials. These data suggest that clearly divided sections exist within the microfibril along its axis in a regular manner at an interval of about 200 Å. This cannot be explained in terms of the fringed micelle model. On the other hand, the possibility that cellulose II may have a folded-chain conformation has been demonstrated. A single cellulose molecule is essentially folded back and forth in the (101) plane to form a sheetlike structure. Such a structure is the basic unit that can fit perfectly into the unit cell of cellulose II. The cellulose molecule can achieve a fairly sharp U-turn in the (101) plane, with only one glucose unit of in the half-boat conformation. A crystallite consists of a number of sheets held together by secondary forces in the (101) plane. Accordingly, crystallographically, the crystallites are closely packed at the surface of each fold at its longitudinal edges to make up the cellulose microfibril. According to our model, the oxygen atom of the glucosidic link in the fold, where acid hydrolysis would have to take place, protrudes partially from the surface of the crystallite; a pair of atoms at the folds are then facing each other and are therefore, accessible for hydrolysis. This would explain chain scission of cellulose II at these sites in hydrolysis. This folded-chain model is supported further by other experimental evidence.     

Photoinduced DNA end capping via N3-methyl-5-cyanovinyl-2'-deoxyuridine

A modified oligodeoxynucleotide (ODN) containing N(3)-methyl-5-cyanovinyl-2'-deoxyuridine reacts by photoirradiation at 366 nm with an adenine residue of a complementary template ODN to yield an end-capped ODN in 87% yield.