Molecular orbital calculation of the electronic structure of poly(N-vinylcarbazole)

Energy levels and molecular orbital wave functions of π-electrons in a carbazole ring are calculated by the ω-method. The result agrees well with observed optical absorption spectra of carbazole and poly(N-vinylcarbazole) (PVCA). Molecular orbital wave functions are obtained for a PVCA chain in a 3/1 helix. The overlap integral between adjacent carbazole rings is evaluated for each molecular orbital of the ring. The result affords evidence for hole conduction in PVCA and explains the photoconductivity spectrum under high de field.     

Acute toxicity and rapid excretion in urine of tetramethylarsonium salts found in some marine animals

Acute toxicity in mice, and excretion in their urine, of tetramethylarsonium salts which are arsenic compounds found in some marine animals, were examined using synthetic tetramethylarsonium iodide. The oral, intraperitoneal and intravenous LD₅₀ values of tetramethylarsonium iodide [(CH₃)₄As⁺I^?] were determined to be 890, 175 and 82 mg kg^?1, respectively. When sublethal doses of tetramethylarsonium iodide were orally administered to mice, 53–58% of the arsenic administered was recovered in urine after 6 h and 65–81% after 72 h. High-performance liquid chromatography–inductively coupled plasma (HPLC–ICP) and fast atom bombardment mass spectrometric (FAB MS) analyses revealed that a tetramethylarsonium salt was the only arsenic compound excreted in urine. These results suggested that the major part of orally administered tetramethylarsonium iodide was absorbed from the gastrointestinal tract in mice and then rapidly excreted in urine without biotransformation.     

Application of the vanadium(V)-xylenol orange reagent to the assay of serum glucose

The VXO reagent (mixture of V(V) and xylenol orange) provided in our earlier studies is found very useful for the colorimetric determination of traces of hydrogen peroxide. In this paper the reagent is successfully extended to the assay of glucose in serum by the combined use of glucose oxidase.The VXO reagent exhibited a characteristic absorption maximum at 582 nm, and the presence of glucose together with glucose oxidase led to a significant decrease in the absorbance of the reagent. A linear relation was found between the magnitude of the decrease and glucose concentration in the range of 5 to 400 mg/100 ml. The average recovery of glucose added in serum was 98.6% and the data were reliable with a coefficient of variation below 3.0%. A good correlation to the method by 4-aminoantipyrine-phenol was found: r = 0.970. Ascorbic acid and uric acid did not interfere with the assay.     

Pavoninins,shark-repelling and ichthyotoxic steroid n-acetylglucosaminides from the defense secretion of the sole pardachirus pavoninus (soleidae)

Six steroid itN-acctylglueosaminides, pavoninins-1 to -6, have been isolated from the defense secretion of the sole P. pavoninus guided by ichthyotoxicity and hemolytic activity, and their structures determined to be 1–6 by spcctroscopic studies and chemical correlations. The pavoninins are considered to be the factors responsible for the repellent property of the sole against predatory fishes.     

The Weyl functional near the Yamabe invariant

For a compact manifold M ofdim M=n≥4, we study two conformal invariants of a conformal class C on M. These are the Yamabe constant Y_C(M) and the L^n/2-norm W_C(M) of the Weyl curvature. We prove that for any manifold M there exists a conformal class C such that the Yamabe constant Y_C(M) is arbitrarily close to the Yamabe invariant Y(M), and, at the same time, the constant W_C(M) is arbitrarily large. We study the image of the mapYW:C→(Y_C(M), W_C(M))∈R ² near the line {(Y(M), w)|w∈R}. We also apply our results to certain classes of 4-manifolds, in particular, minimal compact Kähler surfaces of Kodaira dimension 0, 1 or 2.     

Determination of selenium in sediments by fluorimetry with 2,3-diaminonaphthalene after an improved pretreatment by tellurium coprecipitation

Summary An improved fluorimetric method for the determination of selenium in estuary sediments and sedimentary core samples is described. For the separation of selenium, coprecipitation with tellurium-ascorbic acid method gave satisfactory results. The status of the pollution caused by selenium in Nagoya area, which is one of the most industrially active areas in Japan, was estimated, based on the results obtained with this method. Several g/g of selenium were determined in the sediments. Interferences by foreign ions were eliminated by the coprecipitation procedure. Selenium added was recovered by 95–101%.

---

Selenbestimmung in Sedimenten mit Hilfe der Fluorimetrie mit 2,3-Diaminonaphthalin nach einer verbesserten Vorbehandlung durch Tellur-Mitfällung

Zusammenfassung Gehalte bis zu mehreren g/g Selen wurden nach dem verbesserten Verfahren in den Sedimenten des Hafens von Nagoya bestimmt. Störungen durch Fremdionen wurden durch das Mitfällungsverfahren mit Tellur/Ascorbinsäure verhindert. Zugesetztes Selen wurde zu 95 bis 101% wiedergefunden.