Synthesis and properties of weakly coupled dendrimeric multiporphyrin light-harvesting arrays and hole-storage reservoirsElectronic supplementary information (ESI) available: a description of multiphoton effects at high excitation intensities; the complete Experimental section including descriptions of the syntheses of the arrays; SEC data, 1H NMR spectra, and mass spectra for all new porphyrins and multiporphyrin arrays; a description of exploratory studies in the purification of Zn20Fb; data from a comparative study of analytical SEC conditions; representative mass spectral data under different conditions; and representative absorption and fluorescence spectra of the arrays. See http://www.rsc.org/suppdata/jm/b1/b105108n/

2001 ◽  
Vol 12 (1) ◽  
pp. 65-80 ◽  
Keyword(s):  
Comparative Study ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Fluorescence Spectra ◽  
Supplementary Information ◽  
High Excitation ◽  
Absorption And Fluorescence Spectra ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Weakly Coupled

scholarly journals Novel archaeal macrocyclic diether core membrane lipids in a methane-derived carbonate crust from a mud volcano in the Sorokin Trough, NE Black Sea

Archaea ◽  
2003 ◽  
Vol 1 (3) ◽  
pp. 165-173 ◽  
Author(s):  
Alina Stadnitskaia ◽  
Marianne Baas ◽  
Michael K. Ivanov ◽  
Tjeerd C. E. Van Weering ◽  
Jaap S. Sinninghe Damsté
Keyword(s):  
Black Sea ◽  
Mass Spectra ◽  
Membrane Lipids ◽  
Mud Volcano ◽  
The Novel ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Carbonate Formation ◽  
Carbonate Crust ◽  
Archaeal Lipids

A methane-derived carbonate crust was collected from the recently discovered NIOZ mud volcano in the Sorokin Trough, NE Black Sea during the 11th Training-through-Research cruise of the R/V Professor Logachev. Among several specific bacterial and archaeal membrane lipids present in this crust, two novel macrocyclic diphytanyl glycerol diethers, containing one or two cyclopentane rings, were detected. Their structures were tentatively identified based on the interpretation of mass spectra, comparison with previously reported mass spectral data, and a hydrogenation experiment. This macrocyclic type of archaeal core membrane diether lipid has so far been identified only in the deep-sea hydrothermal vent methanogenMethanococcus jannaschii. Here, we provide the first evidence that these macrocyclic diethers can also contain internal cyclopentane rings. The molecular structure of the novel diethers resembles that of dibiphytanyl tetraethers in which biphytane chains, containing one and two pentacyclic rings, also occur. Such tetraethers were abundant in the crust. Compound-specific isotope measurements revealed δ13C values of –104 to –111‰ for these new archaeal lipids, indicating that they are derived from methanotrophic archaea acting within anaerobic methane-oxidizing consortia, which subsequently induce authigenic carbonate formation.

Glandular Trichomes and the Yolatiles Obtained by Steam Distillation of Quercus robur Leaves

1993 ◽  
Vol 48 (9-10) ◽  
pp. 736-744 ◽  
Author(s):  
Ralf Engel ◽  
Paul-Gerhard Gülz ◽  
Thorsten Herrmann ◽  
Adolf Nahrstedt
Keyword(s):  
Electron Microscopy ◽  
Quercus Robur ◽  
Mass Spectra ◽  
Steam Distillation ◽  
Glandular Trichomes ◽  
Retention Indices ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Kováts Indices ◽  
Scanning Electron

Glandular trichomes in form of long stretched tubes are present on the lower leaf side of Quercus robur as shown by scanning electron microscopy. The glands contain an essential oil, which was isolated by steam distillation together with volatile waxy components of the leaves in an amount of 0.025% of fresh leaves. The product of steam distillation was analyzed by GC-MS. Identification of com pounds is based on comparison of their mass spectral data with those of authentic samples in combination with retention indices and MS data using the SeKoMS (Search Kovats Indices and Mass Spectra) Library. Altogether 184 components of the product of steam distillation were separated, 155 of which could be identified, another 7 were tentatively assigned. Three groups of substances according to their chemical composition are found: hexenyl derivatives and some acetals (32%); terpenes including monoterpenes (4% ), sesquiterpenes and diterpenes (21%); and alkane derivatives (35%). The residual 8% consist of benzyl alcohol, com pounds which stem from the degradation of carotenes, and miscellaneous constituents

Mass Spectra of Some Carbamates and Related Ureas. II

1968 ◽  
Vol 51 (2) ◽  
pp. 347-365 ◽  
Author(s):  
W R Benson ◽  
J N Damico
Keyword(s):  
Spectral Data ◽  
Relative Abundance ◽  
Mass Spectra ◽  
The Other ◽  
Methyl Isocyanate ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Fragmentation Patterns ◽  
Sulfur Containing

Abstract Mass spectral data for fourteen carbamates, live dithiocarbamates, one thiocarbamate, and eight phenylureas are given with some interpretations. Among the compounds examined were some sulfur-containing aliphatic oxime carbamates; these lost the sulfur moieties more easily than the methyl isocyanate moiety. In the aryl IV-methylcarbamate series, the CH3NCO moiety appears to be lost most easily, as it is in pyrolysis. When l-(2-chlorophenyI)-3- methylurea is fragmented, unexpectedly the [HNC0]+ ion is found in high relative abundance. However, the remaining ureas undergo fragmentation in a manner similar to their related carbamates. Although the two ethylene bisdithiocarbamates give essentially identical fragmentation patterns, the spectra of the other four thio- and dithiocarbamates show sufficient differences so that they may be distinguished from one another.

scholarly journals Novel Approaches to Visualization and Data Mining Reveals Diagnostic Information in the Low Amplitude Region of Serum Mass Spectra from Ovarian Cancer Patients

2004 ◽  
Vol 19 (4-5) ◽  
pp. 197-207 ◽  
Author(s):  
Donald J. Johann ◽  
Michael D. McGuigan ◽  
Stanimire Tomov ◽  
Vincent A. Fusaro ◽  
Sally Ross ◽  
...  
Keyword(s):  
Data Mining ◽  
Ovarian Cancer ◽  
High Resolution ◽  
Cancer Patients ◽  
Data Reduction ◽  
Mass Spectra ◽  
Diagnostic Information ◽  
Mass Spectral Data ◽  
Mining Operations ◽  
Mass Spectral

The ability to identify patterns of diagnostic signatures in proteomic data generated by high throughput mass spectrometry (MS) based serum analysis has recently generated much excitement and interest from the scientific community. These data sets can be very large, with high-resolution MS instrumentation producing 1–2 million data points per sample. Approaches to analyze mass spectral data using unsupervised and supervised data mining operations would greatly benefit from tools that effectively allow for data reduction without losing important diagnostic information. In the past, investigators have proposed approaches where data reduction is performed bya priori“peak picking” and alignment/warping/smoothing components using rule-based signal-to-noise measurements. Unfortunately, while this type of system has been employed for gene microarray analysis, it is unclear whether it will be effective in the analysis of mass spectral data, which unlike microarray data, is comprised of continuous measurement operations. Moreover, it is unclear where true signal begins and noise ends. Therefore, we have developed an approach to MS data analysis using new types of data visualization and mining operations in which data reduction is accomplished by culling via the intensity of the peaks themselves instead of by location. Applying this new analysis method on a large study set of high resolution mass spectra from healthy and ovarian cancer patients, shows that all of the diagnostic information is contained within the very lowest amplitude regions of the mass spectra. This region can then be selected and studied to identify the exact location and amplitude of the diagnostic biomarkers.

Flavan derivatives. XXV. Mass spectra of 3-hydroxyflavanones, flavan-3-ols, and flavan-3,4-diols

1968 ◽  
Vol 21 (12) ◽  
pp. 3025 ◽  
Author(s):  
JW Clark-Lewis
Keyword(s):  
Mass Spectra ◽  
Hydrogen Transfer ◽  
Diels Alder ◽  
Hydroxyl Group ◽  
Mass Spectral Data ◽  
Insertion Technique ◽  
Mass Spectral ◽  
Marked Enhancement ◽  
Characteristic Fragmentation ◽  
Fragmentation Patterns

Mass spectral data are reported for eight 3-hydroxyflavanones, ten flavan-3-ols, and twelve flavan-3,4-diol derivatives. The principal fragmentation of each of these three classes of compound yields ions derived by retro Diels-Alder fission of the heterocyclic nucleus, accompanied in the case of 3-hydroxyflavanones and flavan-3-ols by hydrogen transfer from the 3-hydroxyl group to the A ring fragment. Deuteration experiments with flavan-3-ols confirmed the origin of the hydrogen atom transferred. Flavan-3,4-diols show two characteristic fragmentation patterns depending on the insertion technique. Mass spectra obtained by indirect insertion of flavan-3,4-diols showed a very marked enhancement of the intensities of the M-18 and M-18-28 peaks, and of their fragmentation ions, compared with spectra obtained by direct insertion.

Comparative study of methods of computer-matching mass spectra. II

1976 ◽  
Vol 29 (3) ◽  
pp. 689 ◽  
Author(s):  
RJ Mathews ◽  
JD Morrison
Keyword(s):  
Comparative Study ◽  
Mass Spectra ◽  
Retrieval System ◽  
Mass Spectral

The performance of different methods of computer-matching mass spectra has been examined for several different classes of compounds that are frequently analysed in our laboratories. We have chosen to retain systems employing the 'Big-6' and 'Big-8' peaks, and then examine doubtful identifications with a Conversational Mass Spectral Retrieval System.

Umsetzung von 2-Dimethylamino-3-methyl- [1.3.2] oxazarsolan mit Protonensäuren / Reaction of 2-Dimethylamino-3-methyl-[1,3,2]oxazarsolan with Acid Molecules

1976 ◽  
Vol 31 (2) ◽  
pp. 246-250 ◽  
Author(s):  
Oswald Adler ◽  
Friedhelm Kober
Keyword(s):  
Molecular Weight ◽  
Spectral Data ◽  
Alkyl Group ◽  
Mass Spectra ◽  
Chemical Ionization ◽  
Mass Spectral Data ◽  
Mass Spectral

The reactions of 2-dimethylamino-3-methyl-[1,3,2]oxazarsolane with acid molecules HXR, H2X, HNR2 and H2NR (X = O, S; R = alkyl-group) are examined. IR, NMR and mass spectral data of the obtained arsolanes are discussed. The molecular weight determinations and the mass spectra with chemical ionization show an assoziation by As–N–Asor As–X–As-bridges.

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