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  • Analytical Chemistry and Spectroscopy  (8)
  • Carbon disulfide  (2)
  • in infants and children  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 128 (1997), S. 881-891 
    ISSN: 1434-4475
    Keywords: 2-Methoxymethylpyrrolidine ; Carbon disulfide ; Pyrrolidine-1-dithiocarboxylates ; Crystal structure ; Diastereomers ; HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Formation of the 2-methoxymethyl-pyrrolidine-1-dithiocarboxylates2–4 and alkylation of2 and3 were studied. Enantiomeric and diastereomeric derivatives of4, the preparation of diastereomeric mixtures of4 by alkylation of3 in the presence of strong bases, and formation of6 by phase transfer alkylation of2 are described. The two enantiomers of 2-(4-bromophenyl)-2-oxo-ethyl 2-methoxymethylpyrrolidine-1-dithiocarboxylate2 have been characterized by X-ray analysis.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2161
    Keywords: Key words Joints ; sacroiliac ; Children ; skeletal system ; MR contrast enhancement ; Arthritis ; in infants and children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. To determine in a prospective study the normal MRI morphology of the sacroiliac joints (SIJs) in relation to age and sex during adolescence. Design and patients. A total of 98 children (63 boys, mean age 12.7±2.8 years; 35 girls, mean age 13.7±2.3 years), ranging in age from 8 to 17 years, with juvenile chronic arthritis (JCA) but without signs of sacroiliitis fulfilled the study prerequisites (no back pain and no pathologic changes of the SIJs on physical examination before MRI in a 1.5-year follow-up). An additional eight HLA-B27-negative boys and eight HLA-B27-negative girls without arthritis served as controls. The MRI protocol comprised a T1-weighted SE sequence, an opposed-phase T2*-weighted GE sequence, and a dynamic contrast-enhanced study in single-section technique. Results. Noncontrast MRI permitted differentiation of “open” from ossified segmental and lateral apophyses of the sacral wings, with a significant difference in age (P 〈0.05) between children with open and ossified apophyses. Ossification of the apophyses of the sacral wings was seen significantly earlier (P 〈0.05) in girls than in boys. Girls also had a significantly higher incidence of transitional lumbosacral vertebrae, pelvic asymmetries, and accessory joints. In the contrast-enhanced opposed-phase MRI study, normal cartilage of the SIJs showed no contrast enhancement whereas the joint capsule showed a moderate enhancement. Conclusion. There are significant age- and sex-related differences in the normal MRI morphology of juvenile SIJs. Our findings might serve as a standard of comparison for the evaluation of pathologic changes – in particular for the early identification of juvenile sacroiliitis.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2161
    Keywords: Key words MR imaging ; Sacroiliitis ; Spondyloarthropathy ; Arthritis ; in infants and children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Purpose. To verify the diagnostic value of contrast-enhanced MR imaging compared with conventional radiography in the diagnosis of sacroiliitis in children. Design and patients. Radiography and MR imaging of the sacroiliac joints were performed in 185 children subdivided into the following groups according to the modified European Spondyloarthropathy (SpA) Study Group (ESSG) criteria: group 1, undifferentiated spondyloarthropathy (uSpA) (n=53, 94.5% HLA-B27+); group 2, differentiated SpA (n=45, 93.3% HLA-B27+); group 3, patients with no signs of SpA other than oligoarthritis (n=39, 92.3% HLA-B27+); group 4, HLA-B27+ controls with various other non-SpA diagnoses (n=22); and group 5, HLA-B27– controls with various other non-SpA diagnoses (n=26). Radiographs were evaluated on the basis of the modified New York criteria independently by three experienced radiologists masked to the clinical data. In a second step, the same radiologists independently evaluated the MR images without knowledge of the clinical data and radiographic findings using the recently published criteria developed by our group. These criteria allow differentiation of acute and chronic inflammatory changes. Results. Radiography demonstrated sacroiliitis in 18 patients: 4 of 53 in group 1 (7.5%), 14 of 45 in group 2 (31%), but none in groups 3, 4 and 5. In contrast, MR imaging demonstrated acute and/or chronic sacroiliitis in 44 patients: 18 of 53 in group 1 (34%), 21 of 45 in group 2 (46.7%) and 5 of 39 in group 3 (12.8%), but none in groups 4 and 5. The percentage of sacroiliitis detected by MR imaging was significantly higher than that detected by radiography (P〈0.001). Conclusion. Contrast-enhanced MR imaging is a useful method for detecting sacroiliitis in children. Advantages of contrast-enhanced MR imaging compared with conventional radiography are a higher sensitivity due to the ability to document early and acute changes and the absence of radiation exposure.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0935-6304
    Keywords: Reversed phase LC-GC ; Vaporizer/percolumn solvent split/gas discharge system ; Phthalates in water ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reversed phase liquid chromatography (RPLC) was coupled on-line to gas chromatography (GC) via the vaporizer chamber/preco-lumn solvent split/gas discharge interface outlined recently. Water-containing eluents were driven into a vaporizer chamber at 300°C by the LC pump. The Vapors were removed through an early vapor exist by the carrier gas. Solvent/solute separation occurred in hte retaining precolumn. Special attention was paid to the parame-ters determining the losses of the most volatile compounds. The oven temperature during transfer was lowered close to the dew point of the eluent (the temperature at which recondensation occurs) in order to maximise the retention power of the retaining precolumn. The dew point depends on the transfer rate, the gas flow rate, and the gas inlet pressure. Sometimes even better retention of the vola-tiles was observed at temperatures below the dew point, i.e. despite partial reconsideration. The method was applied to the analysis of phthalates in drinking and surface waters. The detection limits, using MS, were 5-10 ng/l.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 89-95 
    ISSN: 0935-6304
    Keywords: Gas chromatography, GC ; Injector design ; Splitless injection ; Injector overflow ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Injector overflow is determined quantitatively by analysis of the septum purge effluent. Vaporizing chambers must have an internal volume of about 1 ml (e.g. 80 × 3.6 mm i.d.). This allows splitless injection of volumes between 1 and 2.5 μl, depending on the solvent. The septum purge should be closed during splitless transfer to prevent losses by back-diffusion.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 613-614 
    ISSN: 0935-6304
    Keywords: Press fit connections ; High temperature fused silica ; Polyimide ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recently introduced fused silica, primarily of the high temperature type, no longer allows the formation of a reliable press-fit seal. Attempts to tighten the connection with various kinds of glue proved unsatisfactory. Manufacturers of fused silica tubing are urged to devote more attention to the problem.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 49-50 
    ISSN: 0935-6304
    Keywords: Coupled LC-GC ; Olive oil ; Erythrodiol ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 591-598 
    ISSN: 0935-6304
    Keywords: On-line coupled LC-GC ; Partially concurrent eluent evaporation ; Early vapor exit ; Retaining pre-column ; Irradiated fat ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper reports two subjects. It describes LC-GC transfer by partially concurrent eluent evaporation at a greatly accelerated rate, as required for optimal compatibility with 2-3 mm i.d. LC columns and LC flow rates up to some 500 μl/min. Evaporation rates around 200 μl/min were obtained using a 0.53 mm. i.d. uncoated pre-column and an early vapor exit. A stationary-phasecoated “retaining” pre-column was used for preventing escape of volatile solutes through the vapor exit.The technique was used for the detection of food irradiation by analyzing selected radiolysis products of triglycerides, namely alkanes/alkanes and aldehydes. Extracted fat of chicken, hazel-nuts, and soup mixes was injected in LO and the relevant fractions were transferred on-line to GC. For chicken and nuts, detection of irradiation was possible down to doses below 0.5 kGy. Detection limits were higher for soup mixes due to interfering peaks.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 33-39 
    ISSN: 0935-6304
    Keywords: Coupled LC-GC ; Group-type analysis ; Mineral oil ; Batching oil (jute) ; Food contamination by hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatics of a C15—C30 mineral oil fraction, the “batching oil” used for producing jute fabrics, were analyzed for estimating the toxicity of oil transferred from jute bags to foods. Group-type pre-separation according to ring systems occurred on a LC NH2 column with pentane and small additions of methanol as eluent. LC fractions were characterized by LC-GC-MS and quantitated by LC-GC-FID. The oil contained 23% aromatics and 1% “polars”; some 99.5% of the aromatics were alkylated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 573-578 
    ISSN: 0935-6304
    Keywords: Large sample volumes ; Vaporizing chambers ; Evaporation rates ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The suitability of some chambers for sample evaporation at high input flow rates (〉100 μl/min) was studied by visual experiments. The chambers were at temperatures far above the solvent boiling point in order to achieve the heat transfer required. Shooting liquid owing to violent evaporation, flooding of the chamber as a result of cooling, and excessively high vapor pressure causing backflow into the gas supply system were found to be the limiting factors. Fused silica capillaries into which a piece of wire or polyimide-free fused silica capillary had been inserted were found to be suitable for the vaporization of “easy” solvents, such as alkanes (up to some 1.7 ml/min), but packed beds were required to achieve favorable evaporation of dichloromethane or methanol/water (up to some 800 and 300 μl/min, respectively).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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