No abstract

This ganglioside is highly immunogenic, and immunization of mice with this disialoganglioside fraction coated on Salmonella minnesota followed by fusion of immunized spleen cells with mouse myeloma and selection of the hybridoma by positive reactivity with the purified disialoganglioside resulted in the establishment of a hybridoma secreting immunoglobulin G2a antibody FH9 that reacts specifically with the ganglioside antigen above but not with monosialosyllactotetraosylceramide I (IV3NeuAcLc4), monosialosyllactotetraosylceramide II (III6NeuAcLc4), or any other gangliosides tested.

N-chloromorpholine to transfer their active chlorine to a suitable acceptor have been determined from both thermodynamic and kinetic standpoints. The secondary chloramines, although extremely weak bases, appear to react only in their protonated form. Of the tertiary N-chloro-ions. only N-chloroquinuclidinium ion and related bridgehead-nitrogen compounds are sufficiently stable to permit evaluation of their thermodynamic properties. The tendency to donate positive chlorine changes at pH 7 by a factor of lo6 on going from diethylchloramine to Nchloroquinuclidinium ion. The work partly overlaps the classical studies of Soper and his co-workers although the experimental approaches and some of the results differ substantially.

Oriental lacquer has been used as a surface coating for wood, porcelain and metal, and three different types are known: Japanese (or Chinese) lacquer (urushiol‐based), Vietnamese lacquer (laccol‐based) and Burmese lacquer (thitsiol‐based). Identification of these types in ancient coatings is very important in conservation and restoration studies. A two‐stage pyrolysis‐gas chromatography/mass spectrometry method is effective for the analysis of lacquer films. This is shown here using an ancient lacquer film sample from medieval material excavated at Tobarikyu (Japan), The sample was identified, by comparison with linseed oil and authentic lacquer films, as an urushiol‐based Rhus vernicifera (Japanese) lacquer which includes an added oil component.

, which correspond to the expulsion of one of the substituents on the central carbon atom. These fragment ions further decompose into various ions following hydrogen or skeletal rearrangement in the metastable time window. In a review of the mass spectra of compounds of this type, Beynon et al. have emphasized that deuterium labeling would seem to offer the only means of elucidating the true fragmentation process. ) from 1,1-dimethoxyethane, (CH 3 CH(OCH 3 ) 2 , 2).6 Further, they have reported that the metastable ion at m/z 45 (CH 2 =O CH 3 ) from 1 Á decomposes into the m/z 29 ion (CH 4 loss) in preference to the m/z 19 ion (C 2 H 2 loss). 7 The structure of the m/z 59 ion) from 2 Á has been investigated by measuring the intensity ratio of m*(H 2 O) and m*(C 2 H 4 ), where m*(X) is the intensity of the metastable peak corresponding to the loss of X from the m/z 59 ion. 8 The suggestion of Beynon et al.3 prompted us to reinvestigate the fragmentation mechanims of RR'C (OCH 3 ) 2 ions by using mass-analyzed ion kinetic energy (MIKE) spectrometry and D-labeling. In a preliminary report, we have proposed that sequential transfers of a methyl group and a hydrogen atom occur during the fragmentations of [M À H] from 1 and 2. 9 In this paper, more detailed fragmentation pathways of 1 and 2 are reported. The relative abundances of the ions in the MIKE spectra are rationalized by considering the total heat of formation (AE DH f ) of the ion plus the neutral fragment. EXPERIMENTALThe mass and unimolecular MIKE spectra were obtained using a JEOL JMS-HX100 tandem mass spectrometer. The electron energy was 70 eV, and the ion accelerating voltage was 5 kV. The CID spectrum of protonated ethanol was obtained using a JEOL JMS-DX303 tandem mass spectrometer equipped with a chemical ionization (CI) source. The electron energy was 200 eV, and the ion accelerating voltage was 3 kV. Samples were introduced via a heated (100°C) inlet system from which they were leaked into the ion source (180°C).Samples 1, 2 and ethanol were research grade products from Tokyo Kasei Co. Ltd, and were used without further purification. Ethanol was used as a reference compound. Isobutane was used as a reagent gas for CI. Samples 1-d 6 , (CH 2 (OCD 3 ) 2 ), and 2-d 6 , (CH 3 CH(OCD 3 ) 2 ), were prepared