Found: 7010 publications , showing page 337 of 585
Scientific paper
Enantiomeric separation of TAPP, H-Tyr-(D)Ala-Phe-Phe-NH2, by capillary electrophoresis using 18-crown-6-tetracarboxylic acid as a chiral selector
H. Brunnkvist, B. Karlberg, I. Granelli
2003
| J. Chromatogr. B
| 793
(343-350)
A capillary electrophoresis method for the enantiomeric separation of the tetrapeptide H–Tyr–(d)Ala–Phe–Phe–NH2 (TAPP), has been developed and validated. The preferred background electrolyte (BGE) consisted of 0.1 M aqueous phosphoric acid adjusted to pH 3.0 with triethanolamine. The chiral selectors 18-crown-6-tetracarboxylic acid (18C6H4) and heptakis(2,6-di-O-methyl)-β-cyclodextrin (2,6-DM-β-CD) were compared and the crown ether 18C6H4 was found to be superior. The separation of TAPP and its enantiomer was accomplished within 30 min with a resolution greater than 3.5. The method was then investigated with respect to selectivity, linearity, accuracy, range, precision, detection limit (DL), quantitation limit (QL) and robustness, essentially following International Conference of Harmonisation (ICH) guidelines for the validation of analytical methods. The DL and QL for the TAPP enantiomer were found to be 0.3 and 0.8%, respectively, at the target TAPP concentration of 1 mg/ml. Robustness was tested using a full factorial design for the following four experimental variables varied at two levels: pH of the BGE, chiral selector concentration in the BGE, phosphoric acid concentration in the BGE, and temperature. The method showed good performance with respect to all of the validation parameters, and proved to be robust to changes in the experimental parameters within the tested domain.
Scientific paper
A field survey of chemicals and biological products used in shrimp farming.
A baseline model for deposition in an emission test bench
Jansson, A.; Dessagne, J-M.; Fronius, J.; Heimann, M.; Mark, D.; Rautio, S.
2003
| Ventilation 2003
(403-408)
Technical report
Trängselavgifter i Stockholm ? Luftkvalitetsförändringars beräknade hälsokonsekvenser.
Forsberg, B.; Segerstedt, B.; Johansson, C.
2003
| SEPA & Statens folkhälsoinstitut
Scientific paper
Motilin-bicelle interactions: membrane position and translational diffusion
Andersson, A; Maler, L
2003
| FEBS Lett.
| 545
(2-3)
(139-143)
Presentation abstract
trans-norpinic, pinic and cis-pinonic acid in the forest aerosol.
Levin, A.; Wideqvist, U.; Alsberg, T. & Janson
2003
NCoE/BACCI Workshop on Atmospheric Aerosols, Formation and Chemistry
biogenic secondary organic aerosol
,
monoterpenes
,
soa
Presentation abstract
Predicted health impacts of road pricing in Stockholm ? a local assessment.
Forsberg, B.; Johansson, C.; Segerstedt, B. & Burman
2003
2nd AIRNET Annual Conference / NERAM International Colloquium
congestion fees
,
no2
,
pm10
,
traffic planning
Technical report
Provningsjämförelser av Aluminiumfraktioner 2001 & 2002.
Andrén, C.
2003
| Department of Applied Environmental Science (ITM)
(1-44)
| Report No: 117
Scientific paper
Screening of Biomarkers in Rat Urine Using LC/Electrospray Ionization-MS and Two-Way Data Analysis
H T. Idborg, Edlund, Per-Olof, Kvalheim, Olav M, Schuppe-Koistinen, Ina, S P. Jacobsson
2003
| 75(18)
(4784-4792)
Biofluids, like urine, form very complex matrixes containing a large number of potential biomarkers, that is, changes of endogenous metabolites in response to xenobiotic exposure. This paper describes a fast and sensitive method of screening biomarkers in rat urine. Biomarkers for phospholipidosis, induced by an antidepressant drug, were studied. Urine samples from rats exposed to citalopram were analyzed using solid-phase extraction (SPE) and liquid chromatography mass spectrometry (LC/MS) analysis detecting negative ions. A fast iterative method, called Gentle, was used for the automatic curve resolution, and metabolic fingerprints were obtained. After peak alignment principal component analysis (PCA) was performed for pattern recognition, PCA loadings were studied as a means of discovering potential biomarkers. In this study a number of potential biomarkers of phospholipidosis in rats are discussed. They are reported by their retention time and base peak, as their identification is not within the scope of the study. In addition to the fact that it was possible to differentiate control samples from dosed samples, the data were very easy to interpret, and signals from xenobiotic-related substances were easily removed without affecting the endogenous compounds. The proposed method is a complement or an alternative to NMR for metabolomic applications.
Scientific paper
Stable carbon and nitrogen isotopes in lake plankton and seston: variability among 10 fractions, two seasons, and two lakes.
Vuorio, K.; Ventelä, A.-M.; Sipura, J.; Tarvainen, M.; Meili, M.; Sarvala, J.