| 1. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 2. |
- Agmon-Levin, Nancy, et al.
(författare)
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International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies
- 2014
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 73:1, s. 17-23
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Tidskriftsartikel (refereegranskat)abstract
- Anti-nuclear antibodies (ANA) are fundamental for the diagnosis of autoimmune diseases, and have been determined by indirect immunofluorescence assay (IIFA) for decades. As the demand for ANA testing increased, alternative techniques were developed challenging the classic IIFA. These alternative platforms differ in their antigen profiles, sensitivity and specificity, raising uncertainties regarding standardisation and interpretation of incongruent results. Therefore, an international group of experts has created recommendations for ANA testing by different methods. Two groups of experts participated in this initiative. The European autoimmunity standardization initiative representing 15 European countries and the International Union of Immunologic Societies/World Health Organization/Arthritis Foundation/Centers for Disease Control and Prevention autoantibody standardising committee. A three-step process followed by a Delphi exercise with closed voting was applied. Twenty-five recommendations for determining ANA (1-13), anti-double stranded DNA antibodies (14-18), specific antibodies (19-23) and validation of methods (24-25) were created. Significant differences between experts were observed regarding recommendations 24-25 (p<0.03). Here, we formulated recommendations for the assessment and interpretation of ANA and associated antibodies. Notably, the roles of IIFA as a reference method, and the importance of defining nuclear and cytoplasmic staining, were emphasised, while the need to incorporate alternative automated methods was acknowledged. Various approaches to overcome discrepancies between methods were suggested of which an improved bench-to-bedside communication is of the utmost importance. These recommendations are based on current knowledge and can enable harmonisation of local algorithms for testing and evaluation of ANA and related autoantibodies. Last but not least, new more appropriate terminologies have been suggested.
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| 3. |
- Axmon, Anna, et al.
(författare)
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CYP1A1 and GSTM1 polymorphisms affect urinary 1-hydroxypyrene levels after PAH exposure
- 2000
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Ingår i: Carcinogenesis. - : Oxford University Press. - 0143-3334 .- 1460-2180. ; 21:4, s. 669-676
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Tidskriftsartikel (refereegranskat)abstract
- Certain human biotransformation enzymes have been implicated in the formation and scavenging of the ultimate reactive metabolites, the diolepoxides, from polycyclic aromatic hydrocarbons (PAHs). In the present study, performed on aluminum smelter workers, we have analyzed airborne PAH, the pyrene metabolite 1-hydroxypyrene (1-OHP) in urine, and genotypes for biotransformation enzymes involved in PAH metabolism. The aim was to evaluate the correlation between external exposure and biomarkers of exposure and to investigate to what extent genetic polymorphism in metabolic enzymes can explain interindividual variation in urinary 1-OHP levels. DNA was prepared from blood samples from 98 potroom workers and 55 controls and altogether eight polymorphisms in the CYP1A1, mEH, GSTM1, GSTP1 and GSTT1 genes were analyzed. The 1-OHP excretion was found to correlate significantly (P 100-fold) and univariate and multivariate regression analyses were used to find the variables that could determine differences in excretion. The variation could, to some degree, be explained by differences in exposure to airborne particulate-associated PAHs, the use of personal respiratory protection devices, smoking habits and genetic polymorphisms in the cytochrome P450 1A1, GSTM1 and GSTT1 enzymes. The part of the variance that could be explained by differences in biotransformation genotypes seemed to be of the same order of magnitude as the variance explained by differences in exposure. In the control group as well as in the occupationally exposed group, the highest 1-OHP levels were observed in individuals carrying the CYP1A1 Ile/Val genotype who were also of the GSTM1 null genotype. The results show that urinary 1-OHP is a sensitive indicator of recent human exposure to PAHs and that it may also to some extent reflect the interindividual variation in susceptibility to PAHs.
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| 4. |
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| 5. |
- Bohlin, Pernilla, et al.
(författare)
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Field evaluation of a passive personal air sampler for screening of PAH exposure in workplaces
- 2010
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 12:7, s. 1437-1444
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Tidskriftsartikel (refereegranskat)abstract
- New sampling methods are needed to simplify and enable frequent monitoring of workers' exposure to polycyclic aromatic hydrocarbons (PAHs). The sampler needs to fulfil some key operational requirements for occupational exposure assessments: (i) be usable as a personal sampler; (ii) work over 8 h exposure time; (iii) sequester PAHs both in gas and particle phase, (iv) yield reliable estimates of air concentrations. Here, a new smaller design of the traditional polyurethane foam (PUF) passive air sampler (PAS) (i.e. a 'mini-PUF') was introduced and assessed against these requirements in sites with elevated PAH concentrations. The exposure times were 2 weeks and 8 hours. The obtained sampling rates (R-values) were not significantly different between gas phase (0.4-3.3 m(3) day(-1), 0.3-2.3 L min(-1)) and particle associated PAHs (0.5-1.9 m(3) day(-1), 0.4-1.3 L min(-1)). The accuracy in estimating air concentrations was within +/-25% from the active sampler for half of the PAHs for the mini-PUF under 8 h exposures. Significant correlations (p < 0.003) were found between personally deployed mini-PUFs and a co-deployed personal active sampling method. This together with the low costs and ease-of-use of the mini-PUF encourage application in exposure assessments.
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| 6. |
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| 7. |
- Claeson, Anna-Sara, 1974-, et al.
(författare)
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Volatile metabolites from microorganisms grown on humid building materials and synthetic media
- 2002
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 667-672
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Tidskriftsartikel (refereegranskat)abstract
- Growth of different microorganisms is often related to dampness in buildings. Both fungi and bacteria produce complicated mixtures of volatile organic compounds that include hydrocarbons, alcohols, ketones, sulfur- and nitrogen-containing compounds etc. Microbially produced substances are one possible explanation of odour problems and negative health effects in buildings affected by microbial growth. A mixture of five fungi, Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi were grown on three different humid building materials (pinewood, particle board and gypsum board) and on one synthetic medium. Six different sampling methods were used, to be able to collect both non-reactive volatile organic compounds and reactive compounds such as volatile amines, aldehydes and carboxylic acids. Analysis was performed using gas chromatography, high-performance liquid chromatography and ion chromatography, mass spectrometry was used for identification of compounds. The main microbially produced metabolites found on pinewood were ketones (e.g. 2-heptanone) and alcohols (e.g. 2-methyl-1-propanol). Some of these compounds were also found on particle board, gypsum board and the synthetic medium, but there were more differences than similarities between the materials. For example, dimethoxymethane and 1,3,5-trioxepane and some nitrogen containing compounds were found only on particle board. The metabolite production on gypsum board was very low, although some terpenes (e.g. 3-carene) could be identified as fungal metabolites. On all materials, except gypsum board, the emission of aldehydes decreased during microbial growth. No low molecular weight carboxylic acids were identified.
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| 8. |
- Claeson, Anna-Sara, 1974-
(författare)
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Volatile organic compounds from microorganisms : identification and health effects
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Damp building materials are subjected to degradation processes due to moisture and also microbial growth, with both of these giving rise to emissions of volatile organic compounds (VOCs) that may contribute to indoor air health problems. The overall aim of this thesis was to investigate emissions of reactive and non-reactive VOCs from damp building materials and from the microorganisms growing on them, and also to investigate the possible health impact of these compounds. Three studies were carried out in order to study emissions of VOCs. The first investigated emissions from a mixture of five fungi (Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi) and the second emissions from the bacterium Streptomyces albidoflavus. In both studies the microorganisms were cultivated on three different building materials (pine wood, particle board and gypsum board) and one synthetic media, MEA and TGEA respectively. The bacterium was also cultivated on sand. Air samples from the cultures were collected on six different adsorbents and chemosorbents to sample a wide range of compounds such as VOCs, aldehydes, amines and light-weight organic acids. The samples were analyzed with gas chromatography, high-pressure liquid chromatography and ion chromatography. Mass spectrometry was used for identification of the compounds. Alcohols and ketones were the predominant compound groups identified. The bacterial culture growing on TGEA emitted ammonia, methylamine, diethylamine and ethylamine. The third study dealt with secondary emissions collected from buildings with moisture and mould problems. Samples were taken when the materials were dry and also after they had been wet for a week. Most alcohols and ketones could be identified from the wet materials. Trimethylamine and triethylamine, were identified from sand contaminated by Bacillus. One study looked at the development of a method for analysis of primary and secondary amines with LC-MS/MS. A three-step process was developed, with the first step screening the samples for NIT derivatives with selected reaction monitoring, SRM. In the second step a precursor ion scan gave the [M+H]+ ion, and the last step involved fragmentation with a product ion scan. It was possible to separate and identify all the investigated amines, which showed that the method was both specific and selective and therefore well suited for the analysis of amines in complex environments. The last study comprised two exposure studies. In study 1 each participant took part in two exposure conditions, one with air from mouldy building materials and one with blank air for a 60 minute period. In study 2 each participant was exposed four times (for a period of 10 min) at random to air from mouldy building materials and blank air, with and without nose-clip. The participants rated air quality and symptoms before, during and after each exposure. Exposure to moderate VOC levels resulted in reports of perceived poor air quality, but no such results were received when exposing the participants to low VOC levels.
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| 9. |
- Ekman, Jenny, et al.
(författare)
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Comparison of sampling methods for 1,6-hexamethylene diisocyanate, (HDI) in a commercial spray box
- 2002
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Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 127:1, s. 169-173
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Tidskriftsartikel (refereegranskat)abstract
- In this study three different types of samplers for the determination of 1,6-hexamethylene diisocyanate in air were compared. The experimental set up was a simulation of real life conditions with spray painting operations performed inside a commercial, full sized, spray box. The sampling methods were 1-(2-methoxyphenyl)-piperazine impregnated on glass fibre filter, and the same reagent in impinger, and also dibutylamine in impinger. All analyses were performed by LC-MS-MS. The determined concentrations varied between 20 and 90 microg m(-3) with relative standard deviations from 7 to 17% for each method. No significant difference was found between the three methods using ANOVA with a significance level of alpha = 0.05.
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| 10. |
- Eriksson, Kåre, et al.
(författare)
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Dermal exposure to terpenic resin acids in Swedish carpentry workshops and sawmills
- 2004
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press. - 0003-4878 .- 1475-3162. ; 48:3, s. 267-275
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of this study was to evaluate dermal exposure to the resin acids abietic acid, dehydroabietic acid and 7-oxodehydroabietic acid during collecting in sawmills and during sawing in carpentry workshops, respectively. METHODS: Sampling was performed by fastening patches at 12 different areas on a sampling overall, one patch on the front of a cap, one patch on the chest inside the clothing and one patch on the inner lower right leg. Exposure of the hands was assessed by fastening patches on cotton gloves representing the dorsal sides and the palms of the left and right hands. Sampling was performed on 30 different occasions in the sawmills and in the carpentry workshops with mean sampling times of 120 and 59 min, respectively. The acids were solvent desorbed from the patches. Identification and quantification of the resin acids was performed by gas chromatography-mass spectrometry. RESULTS: The geometric means (GMs) of the potential body exposures to abietic acid, dehydroabietic acid and 7-oxodehydroabietic acid during sawing and collecting of wood from pine and spruce were 3346 and 17 247 micro g/h, respectively. The GM of the potential exposure on the hands was 3020 micro g/h in the carpentry workshops and 4365 micro g/h in the sawmills. Resin acids were detected on the inner chest and inner lower front right leg, respectively. CONCLUSIONS: There is a potential dermal exposure to terpenic resin acids in carpentry workshops as well as in sawmills. The hands have the highest exposure during sawing as well as during collecting. There is a spatial distribution of contaminants, with the outer chest, arms and legs showing the highest exposures. Resin acids also contaminated the inner chest and inner lower leg. It is necessary to take action to reduce dermal exposure to these allergenic substances.
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| 11. |
- Eriksson, Kåre, et al.
(författare)
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Quantification of melatonin in human saliva by liquid chromatography-tandem mass spectrometry using stable isotope dilution
- 2003
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Ingår i: Journal of chromatography. B. - : Elsevier. - 1570-0232 .- 1873-376X. ; 794:1, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- A method for the determination of melatonin in human saliva has been developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS). Saliva was collected in plastic tubes. 7-D-Melatonin was added as internal standard and the samples were cleaned and concentrated by solid-phase extraction. The limit of detection was 1.05 pg x ml(-1) and the limit of quantification was 3.0 pg x ml(-1). The accuracy of the method was +/-14% at 5.60 pg x ml(-1) and +/-9% at 19.6 pg x ml(-1). The precision was +/-13% at 6.18 pg x ml(-1) and +/-11% at 31.2 pg x ml(-1), respectively. Our HPLC-MS-MS method shows a high sensitivity and specificity for melatonin and more reliable results compared with a radioimmunoassay. The chromatographic method has been used to determine the circadian rhythm of melatonin among three nurses working the night shift and a patient suffering from an inability to fall asleep at night.
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| 12. |
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| 13. |
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| 14. |
- Gustafsson, Maria, 1976, et al.
(författare)
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Retention of Low-Density Lipoprotein in Atherosclerotic Lesions of the Mouse. Evidence for a Role of Lipoprotein Lipase
- 2007
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Ingår i: Circ Res. - 1524-4571. ; 101:8, s. 777-783
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Tidskriftsartikel (refereegranskat)abstract
- Direct binding of apolipoprotein (apo)B-containing lipoproteins to proteoglycans is the initiating event in atherosclerosis, but the processes involved at later stages of development are unclear. Here, we investigated the importance of the apoB-proteoglycan interaction in the development of atherosclerosis over time and investigated the role of lipoprotein lipase (LPL) to facilitate low-density lipoprotein (LDL) retention at later stages of development. Atherosclerosis was analyzed in apoB transgenic mice expressing LDL with normal (control LDL) or reduced proteoglycan-binding (RK3359-3369SA LDL) activity after an atherogenic diet for 0 to 40 weeks. The initiation of atherosclerosis was delayed in mice expressing RK3359-3369SA LDL, but they eventually developed the same level of atherosclerosis as mice expressing control LDL. Retention studies in vivo showed that although higher levels of (131)I-tyramine cellobiose-labeled control LDL ((131)I-TC-LDL) were retained in nonatherosclerotic aortae compared with RK3359-3369SA (131)I-TC-LDL, the retention was significantly higher and there was no difference between the groups in atherosclerotic aortae. Lower levels of control (125)I-TC-LDL and RK3359-3369SA (125)I-TC-LDL were retained in atherosclerotic aortae from ldlr(-/-) mice transplanted with lpl(-/-) compared with lpl(+/+) bone marrow. Uptake of control LDL or RK3359-3369SA LDL into macrophages with specific expression of human catalytically active or inactive LPL was increased compared with control macrophages. Furthermore, transgenic mice expressing catalytically active or inactive LPL developed the same extent of atherosclerosis. Thus, retention of LDL in the artery wall is initiated by direct LDL-proteoglycan binding but shifts to indirect binding with bridging molecules such as LPL.
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| 15. |
- Hagenbjörk-Gustafsson, Annika, 1956-, et al.
(författare)
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Validation of a diffusive sampler for NO2
- 1999
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 1, s. 349-352
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Tidskriftsartikel (refereegranskat)abstract
- A diffusive sampler for NO2, Willems badge, was validated in laboratory experiments and field tests. The collecting reagent for NO2 in the sampler is triethanolamine, and the analysis is based on a modified colorimetric method, theSaltzman method. The analysis was performed by a flow injection analysis (FIA) technique. The sampling rate for the sampler was determined to be 40.0 ml min−1. There was no effect of NO2 concentration or relative humidity on sampling rate, and the influence of sampling time was found to be small. The detection limit was 4 mg m−3 for a 24 hsample. The capacity is high enough to allow sampling of 150 mg m−3 for 7 days, which is twice the recommended Swedish short-term (24 h) guideline value as a 98-percentile over 6 months. In field tests, the sampler performedwell, even at wind speeds higher than 2 m s−1, and at low temperatures. The overall uncertainty of the method was 24%. The sensitivity and capacity of the method also make it suitable for personal sampling for 2–8 h in working environments.
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| 16. |
- Hagenbjörk-Gustafsson, Annika, et al.
(författare)
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Validation of the Willems badge diffusive sampler for nitrogen dioxide determinations in occupational environments
- 2002
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Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 127:1, s. 163-168
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Tidskriftsartikel (refereegranskat)abstract
- The Willems badge, a diffusive sampler for nitrogen dioxide, has previously been validated for ambient air measurements. This paper describes the laboratory and field validation of the Willems badge for personal sampling under working environment conditions. The mean sampling rate in the laboratory tests was 46 ml min(-1), with an RSD of 12%. No statistically significant effects on sampling rate of the sampling time, concentration of NO2 or relative humidity were found. A slightly decreased sampling rate was observed at low wind velocity. This was also confirmed during static sampling, which makes the sampler less appropriate for static sampling indoors. No back diffusion was observed. Storage of the samplers for two weeks before or after exposure did not affect the sampling rate. Our analysis is based on a modified colorimetric method, performed by FIA (flow injection analysis). This technique was compared to ion chromatography analysis. The use of ion chromatography lowered the detection limit from 11 to 2 microg m(-3) for an 8 h sample, and furthermore enabled the detection of other anions. In conclusion, the diffusive sampler was found to perform well for personal measurements in industrial environments.
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| 17. |
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| 18. |
- Hiukka, A, et al.
(författare)
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ApoCIII-Enriched LDL in Type 2 Diabetes Displays Altered Lipid Composition, Increased Susceptibility for Sphingomyelinase and Increased binding to Biglycan.
- 2009
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 58:9, s. 2018-2026
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Tidskriftsartikel (refereegranskat)abstract
- Objective- Apolipoprotein CIII (apoCIII) is an independent risk factor for cardiovascular disease, but the molecular mechanisms involved are poorly understood. Here, we investigated potential proatherogenic properties of apoCIII-containing LDL from hypertriglyceridemic patients with type 2 diabetes. Research design and methods - LDL was isolated from controls and subjects with type 2 diabetes, and from apoB transgenic mice. LDL-biglycan binding was analyzed with a solid-phase assay using immunoplates coated with biglycan. Lipid composition was analyzed with mass spectrometry. Hydrolysis of LDL by sphingomyelinase was analyzed after labeling plasma LDL with [(3)H]sphingomyelin. ApoCIII isoforms were quantified after isoelectric focusing. Human aortic endothelial cells were incubated with desialylated apoCIII or with LDL enriched with specific apoCIII isoforms. Results- We showed that enriching LDL with apoCIII only induced a small increase in LDL-proteoglycan binding, and this effect was dependent on a functional Site A in apoB100. Our findings indicated that intrinsic characteristics of the diabetic LDL other than apoCIII per se are responsible for further increased proteoglycan binding of diabetic LDL with high endogenous apoCIII, and we showed alterations in the lipid composition of diabetic LDL with high apoCIII. We also demonstrated that high apoCIII increased susceptibility of LDL to hydrolysis and aggregation by SMase. In addition, we demonstrated that sialylation of apoCIII increased with increasing apoCIII content, and that sialylation of apoCIII was essential for its proinflammatory properties. Conclusions- We have demonstrated a number of features of apoCIII-containing LDL from hypertriglyceridemic patients with type 2 diabetes that could explain the proatherogenic role of apoCIII.
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| 19. |
- Laudette, Marion, et al.
(författare)
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Cardiomyocyte-specific PCSK9 deficiency compromises mitochondrial bioenergetics and heart function
- 2023
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Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 119:7, s. 1537-1552
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Tidskriftsartikel (refereegranskat)abstract
- Aims Pro-protein convertase subtilisin-kexin type 9 (PCSK9), which is expressed mainly in the liver and at low levels in the heart, regulates cholesterol levels by directing low-density lipoprotein receptors to degradation. Studies to determine the role of PCSK9 in the heart are complicated by the close link between cardiac function and systemic lipid metabolism. Here, we sought to elucidate the function of PCSK9 specifically in the heart by generating and analysing mice with cardiomyocyte-specific Pcsk9 deficiency (CMPcsk9−/− mice) and by silencing Pcsk9 acutely in a cell culture model of adult cardiomyocyte-like cells. Methods and results Mice with cardiomyocyte-specific deletion of Pcsk9 had reduced contractile capacity, impaired cardiac function, and left ventricular dilatation at 28 weeks of age and died prematurely. Transcriptomic analyses revealed alterations of signalling pathways linked to cardiomyopathy and energy metabolism in hearts from CM-Pcsk9−/− mice vs. wild-type littermates. In agreement, levels of genes and proteins involved in mitochondrial metabolism were reduced in CM-Pcsk9−/− hearts. By using a Seahorse flux analyser, we showed that mitochondrial but not glycolytic function was impaired in cardiomyocytes from CM-Pcsk9−/− mice. We further showed that assembly and activity of electron transport chain (ETC) complexes were altered in isolated mitochondria from CM-Pcsk9−/− mice. Circulating lipid levels were unchanged in CM-Pcsk9−/− mice, but the lipid composition of mitochondrial membranes was altered. In addition, cardiomyocytes from CM-Pcsk9−/− mice had an increased number of mitochondria–endoplasmic reticulum contacts and alterations in the morphology of cristae, the physical location of the ETC complexes. We also showed that acute Pcsk9 silencing in adult cardiomyocyte-like cells reduced the activity of ETC complexes and impaired mitochondrial metabolism. Conclusion PCSK9, despite its low expression in cardiomyocytes, contributes to cardiac metabolic function, and PCSK9 deficiency in cardiomyocytes is linked to cardiomyopathy, impaired heart function, and compromised energy production.
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| 20. |
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| 21. |
- Levin, Jan-Olof, 1947-
(författare)
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Experimental studies of kinetic solvent deuterium isotope effects on proton abstraction in alcohol solution
- 1974
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present dissertation is an account based on investigations published in the following papers:I. JAN-OLGF LEVIN and CHRISTOFFER RAPPE, Solvent Deuterium Isotope Effects in Alcohols. I. Racemization of Phenyl2,2-Diphenylcyclopropyl Ketone, 3-Nethyl-4-phenyl-2-butanone and 2-Nethyl-1-indanone. Chem. Scr., 1, 233-235 (1971 ).II. JAN-0L0F LEVIN, Solvent Deuterium Isotope Effects in Alcohols. II. Effect of Solvent-Base System on Kinetic Solvent Isotope Effects in Fiydrogen Abstraction Reactions. Chem. Scr., 4, 85-88 (1973).III. JAN-0L0F LEVIN, Solvent Deuterium Isotope Effects in Alcohols. III. Alkoxide Catalyzed Racemizations of Indenes. Chem. Scr., J5, 89-91 (1974).IV. JAN-OL0F LEVIN, Solvent Deuterium Isotope Effects in Alcohols. IV. Hydrogen Abstraction Reactions in Alcohols Containing Amines. Chem. Scr., in press.These papers will be referred to by the Roman numerals I-IV.
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| 22. |
- Levin, Malin, 1973, et al.
(författare)
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Evaluation of macrophage-specific promoters using lentiviral delivery in mice.
- 2012
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Ingår i: Gene therapy. - : Springer Science and Business Media LLC. - 1476-5462 .- 0969-7128. ; 19:11, s. 1041-7
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Tidskriftsartikel (refereegranskat)abstract
- In gene therapy, tissue-specific promoters are useful tools to direct transgene expression and improve efficiency and safety. Macrophage-specific promoters (MSPs) have previously been published using different delivery systems. In this study, we evaluated five different MSPs fused with green fluorescent protein (GFP) to delineate the one with highest specificity using lentiviral delivery. We compared three variants of the CD68 promoter (full length, the 343-bp proximal part and the 150-bp proximal part) and two variants (in forward and reverse orientation) of a previously characterized synthetic promoter derived from elements of transcription factor genes. We transduced a number of cell lines and primary cells in vitro. In addition, hematopoietic stem cells were transduced with MSPs and transferred into lethally irradiated recipient mice. Fluorescence activated cell sorting analysis was performed to determine the GFP expression in different cell populations both in vitro and in vivo. We showed that MSPs can efficiently be used for lentiviral gene delivery and that the 150-bp proximal part of the CD68 promoter provides primarily macrophage-specific expression of GFP. We propose that this is the best currently available MSP to use for directing transgene expression to macrophage populations in vivo using lentiviral vectors.
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| 23. |
- Levin, Malin, 1973, et al.
(författare)
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Rip2 deficiency leads to increased atherosclerosis despite decreased inflammation.
- 2011
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Ingår i: Circulation research. - 1524-4571. ; 109:11, s. 1210-8
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Tidskriftsartikel (refereegranskat)abstract
- The innate immune system and in particular the pattern-recognition receptors Toll-like receptors have recently been linked to atherosclerosis. Consequently, inhibition of various signaling molecules downstream of the Toll-like receptors has been tested as a strategy to prevent progression of atherosclerosis. Receptor-interacting protein 2 (Rip2) is a serine/threonine kinase that is involved in multiple nuclear factor-κB (NFκB) activation pathways, including Toll-like receptors, and is therefore an interesting potential target for pharmaceutical intervention.
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| 24. |
- Liljelind, Ingrid E, et al.
(författare)
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Comparison of self-assessment and expert assessment of occupational exposure to chemicals
- 2001
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Tyoterveyslaitos, Finnish Institute of Occupational Health. - 0355-3140 .- 1795-990X. ; 27:5, s. 311-317
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Occupational assessments of chemical exposure are often inadequate because of difficulties in obtaining sufficient numbers of measurements by trained professionals (experts). The objective of this study was to determine whether workers can provide unbiased data via self-assessments of exposure facilitated by the use of simple passive monitors for personal sampling.METHODS: Untrained workers obtained personal measurements of their exposures to gaseous contaminants (terpenes in sawmills and styrene in reinforced plastics factories) with passive monitors and written instructions. To study the validity of the self-assessments, an occupational hygienist performed exposure measurements on the same occupational groups after the workers had obtained two or more measurements independently. The potential bias of the self-assessments was evaluated by comparing the self-assessments with the expert assessments in mixed-effects statistical models.RESULTS: A total of 153 terpene (97 self and 56 expert) and 216 styrene (159 self and 57 expert) measurements were obtained from four sawmills and six reinforced plastics factories, respectively. No significant differences in the geometric mean exposures were observed between the self-assessments and the expert assessments in 3 of 4 sawmills and 5 of 6 reinforced plastics factories (P > 0.10). The potential bias of the self-assessments of exposure ranged from less than 0.1% to 102% and was less than 17% in 9 of the 10 groups investigated.CONCLUSIONS: The results indicate that untrained, unsupervised workers are able to collect consistently unbiased exposure data by employing currently available passive monitors.
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| 25. |
- Lindahl, R, et al.
(författare)
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Determination of morpholine in air by derivatisation with 1-naphthylisothiocyanate and HPLC analysis
- 2001
-
Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 126:2, s. 152-154
-
Tidskriftsartikel (refereegranskat)abstract
- A method for the determination of morpholine in air was developed. Samples were collected with adsorbent tubes containing XAD-2 resin coated with 1-naphthylisothiocyanate (NIT). The thiourea derivative formed was subsequently desorbed with acetonitrile and analysed by HPLC with UV detection. The recovery after gas phase spiking with morpholine (2.2-1570 micrograms) was 91% (86-100%) with a relative standard deviation of 5.5%. No effect on recovery from relative humidity or amount of morpholine was seen. The lowest level tested corresponded to 7 mg m-3 (1/10 threshold limit value) for a 15 min sampling period with a sampling rate of 20 ml min-1. Exposed NIT-coated XAD-2 tubes were stable at room temperature for at least 2 weeks.
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| 26. |
- Lindahl, Roger, et al.
(författare)
-
Development of a method for the determination of naphthalene and phenanthrene in workplace air using diffusive sampling and thermal desorption GC-MS analysis
- 2011
-
Ingår i: Annals of Occupational Hygiene. - : Oxford University Press. - 0003-4878 .- 1475-3162. ; 55:6, s. 681-687
-
Tidskriftsartikel (refereegranskat)abstract
- Diffusive sampling methods have been validated for the determination of naphthalene and phenanthrene in workplace air. The diffusive sampler tested was the Perkin Elmer ATD tube, and the analysis was performed with thermal desorption, gas chromatography, and mass spectrometric detection. The sampling methods were validated in controlled test atmospheres, mainly according to the protocol proposed in the European standard EN 838. For the determination of naphthalene, the diffusive sampling rate was 0.41 ml min21 with a coefficient of variation (CV) of 19%. The mean sampling rate for phenanthrene was 0.49 ml min21 with a CV of 21%. Field tests confirmed the naphthalene results but could not be used to confirm the phenanthrene results. The method is not recommended for phenanthrene sampling unless the method has been tested in the specific environment and the results confirm the laboratory tests.
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| 27. |
- Lindahl, Roger, et al.
(författare)
-
Development of a miniaturized diffusive sampler for true breathing-zone sampling and thermal desorption gas chromatographic analysis
- 2009
-
Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 11:7, s. 1340-1344
-
Tidskriftsartikel (refereegranskat)abstract
- Exposure measurements should be performed as close as possible to the nose and mouth for a more correct assessment of exposure. User-friendly sampling equipment, with a minimum of handling before, during and after measurement, should not affect ordinary work. In diffusive (passive) sampling, no extra equipment as sampling pumps is needed, making the measurements more acceptable to the user. The diffusive samplers are normally attached on a shoulder, on a breast-pocket or on the lapel. There are, however, difficulties if true breathing-zone sampling is to be performed, since available diffusive samplers normally cannot be arranged close to the nose/mouth. The purpose of this work was to study the performance of a miniaturized tube type diffusive sampler attached to a headset for true breathing-zone sampling. The basis for this miniaturization was the Perkin Elmer ATD tube. Both the size of the tube and the amount of adsorbent was decreased for the miniaturized sampler. A special tube holder to be used with a headset was designed for the mini tube. The mini tube is thermally desorbed inside a standard PE tube. The new sampler was evaluated for the determination of styrene, both in laboratory experiments and in field measurements. As reference method, diffusive sampling with standard Perkin Elmer tubes, thermal desorption and gas chromatographic (GC) analysis was used. The sampling rate was determined to 0.356 mL min-1 (CV 9.6%) and was not significantly affected by concentration, sampling time or relative humidity.
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| 28. |
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| 29. |
- Modig, Lars, et al.
(författare)
-
Cancerframkallande ämnen i tätortsluft : Exponering och halter i Umeå 2001
- 2002
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Exponeringen för ett antal cancerframkallande ämnen undersöktes i ett slumpmässigt urval av allmänbefolkningen i Umeå, 2001. Den huvudsakliga studien genomfördes från slutet av september till mitten av oktober som personburna 7-dygns mätningar på totalt 60 personer, medan några av mätningarna genomfördes i januari 2002. Parallellt med de personburna mätningarna genomfördes även mätningar vid två stationära platser i Umeå, bibliotekstaket och E4:an. Mätningarna omfattade bensen, 1,3-butadien, formaldehyd, acetaldehyd, PAH (polyaromatiska kolväten) samt kvävedioxid (NO2). Mätningarna genomfördes med passiva provtagare med undantag för PAH där provtagningen genomfördes med hjälp av en pump. Resultatet från de personburna provtagningarna av bensen gav medianvärdet 1,5 μg/m3, vilket kan jämföras med resultatet från fjolårets studie i Göteborg (1μg/m3) och den av Institutet för miljömedicin (IMM) föreslagna lågrisknivån 1,3μg/m3. Exponeringen för bensen var signifikant associerad till tiden som deltagarna vistats inomhus, utomhus på arbetsplatsen, i rum med rökning samt om de var rökare. Det var marginell skillnad mellan medianhalten uppmätt vid E4:an och den personburna halten (1,6 μg/m3 och 1,5 μg/m3) medan halten på bibliotekstaket låg lägre (1,0 μg/m3). Medianvärdet för butadien var 0,4 μg/m3, vilket är samma som halten uppmätt vid E4:an men högre jämfört med halten på bibliotekstaket (0,12 μg/m3). Det var signifikant skillnad mellan rökare och icke-rökare (p=0,007), och tid som tillbringats i rum med rökning var signifikant förknippat med ökad exponering för butadien. Mätningar genomfördes för både formaldehyd och acetaldehyd, dock redovisas enbart resultaten för formaldehyd på grund av problem med provtagningen av acetaldehyd. Bland mätningarna som genomfördes personburet var medianhalten formaldehyd 15 μg/m3 vilket kan jämföras med resultaten från samma studie i Göteborg förra året (19 μg/m3). Resultatet ligger inom det intervall som angivit som lågrisknivå (IMM, 12-60 μg/m3). Halterna som uppmättes vid E4:an och Biblioteket var nästintill lika (3,5 μg/m3 och 3,0 μg/m3), dock var de betydligt lägre jämfört med den halt som uppmättes personburet. Bostadstyp (villa alt lägenhet), framstod som den enda variabeln som var signifikant associerad till den personburna halten formaldehyd. PAH-mätningarna genomfördes stationärt hemma hos 10 deltagare ur befolkningsurvalet, samt personburet och stationärt på 10 personer i anknytning till forskargruppen. Mediankoncentrationen av bens(a)pyren, mätt personburet, var 0,08 ng/m3 vilket är i nivå med resultaten från Göteborg. Halterna hemma hos personerna från befolkningsurvalet samt de med anknytning till kliniken var 0,17 respektive 0,07 ng/m3. De stationära utomhusmätningarna visade att halten vid E4:an var betydligt högre jämfört med halten på Bibliotekstaket (0,3 respektive 0,1 ng/m3). Kvävedioxid (NO2) mättes som ett lokalt tillägg i syfte att undersöka samband mellan NO2, som trafikindikator, och övriga ämnen. Median halten för mätningarna som gjordes personburet var 8 μg/m3 medan resultaten från de stationära mätningarna var betydligt högre. NO2 uppvisade ingen signifikant korrelation till övriga ämnen mätta personburet. Vidare sågs inga samband till vistelse i specifika miljöer.
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| 30. |
- Modig, Lars, et al.
(författare)
-
Cancerframkallande ämnentätortsluft - Umeå 2001
- 2002
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Exponeringen för ett antal cancerframkallande ämnen undersöktes i ett slumpmässigturval av allmänbefolkningen i Umeå, 2001. Den huvudsakliga studien genomfördesfrån slutet av september till mitten av oktober som personburna 7-dygns mätningar påtotalt 60 personer, medan några av mätningarna genomfördes i januari 2002. Parallelltmed de personburna mätningarna genomfördes även mätningar vid två stationäraplatser i Umeå, bibliotekstaket och E4:an. Mätningarna omfattade bensen, 1,3-butadien, formaldehyd, acetaldehyd, PAH (polyaromatiska kolväten) samtkvävedioxid (NO2). Mätningarna genomfördes med passiva provtagare med undantagför PAH där provtagningen genomfördes med hjälp av en pump.Resultatet från de personburna provtagningarna av bensen gav medianvärdet1,5 μg/m3, vilket kan jämföras med resultatet från fjolårets studie i Göteborg (1μg/m3)och den av Institutet för miljömedicin (IMM) föreslagna lågrisknivån 1,3μg/m3.Exponeringen för bensen var signifikant associerad till tiden som deltagarna vistatsinomhus, utomhus på arbetsplatsen, i rum med rökning samt om de var rökare. Detvar marginell skillnad mellan medianhalten uppmätt vid E4:an och den personburnahalten (1,6 μg/m3 och 1,5 μg/m3) medan halten på bibliotekstaket låg lägre (1,0μg/m3).Medianvärdet för butadien var 0,4 μg/m3, vilket är samma som halten uppmätt vidE4:an men högre jämfört med halten på bibliotekstaket (0,12 μg/m3). Det varsignifikant skillnad mellan rökare och icke-rökare (p=0,007), och tid som tillbringats irum med rökning var signifikant förknippat med ökad exponering för butadien.Mätningar genomfördes för både formaldehyd och acetaldehyd, dock redovisas enbartresultaten för formaldehyd på grund av problem med provtagningen av acetaldehyd.Bland mätningarna som genomfördes personburet var medianhalten formaldehyd15 μg/m3 vilket kan jämföras med resultaten från samma studie i Göteborg förra året(19 μg/m3). Resultatet ligger inom det intervall som angivit som lågrisknivå (IMM,12-60 μg/m3). Halterna som uppmättes vid E4:an och Biblioteket var nästintill lika(3,5 μg/m3 och 3,0 μg/m3), dock var de betydligt lägre jämfört med den halt somuppmättes personburet. Bostadstyp (villa alt lägenhet), framstod som den endavariabeln som var signifikant associerad till den personburna halten formaldehyd.PAH-mätningarna genomfördes stationärt hemma hos 10 deltagare urbefolkningsurvalet, samt personburet och stationärt på 10 personer i anknytning tillforskargruppen. Mediankoncentrationen av bens(a)pyren, mätt personburet, var 0,08ng/m3 vilket är i nivå med resultaten från Göteborg. Halterna hemma hos personernafrån befolkningsurvalet samt de med anknytning till kliniken var 0,17 respektive 0,07ng/m3. De stationära utomhusmätningarna visade att halten vid E4:an var betydligthögre jämfört med halten på Bibliotekstaket (0,3 respektive 0,1 ng/m3).Kvävedioxid (NO2) mättes som ett lokalt tillägg i syfte att undersöka samband mellanNO2, som trafikindikator, och övriga ämnen. Median halten för mätningarna somgjordes personburet var 8 μg/m3 medan resultaten från de stationära mätningarna varbetydligt högre. NO2 uppvisade ingen signifikant korrelation till övriga ämnen mättapersonburet. Vidare sågs inga samband till vistelse i specifika miljöer.
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| 31. |
- Nordenhäll, C, et al.
(författare)
-
Airway inflammation following exposure to diesel exhaust : a study of time kinetics using induced sputum
- 2000
-
Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 15:6, s. 1046-1051
-
Tidskriftsartikel (refereegranskat)abstract
- The adverse health effects of particulate matter pollution are of increasing concern. In a recent bronchoscopic study in healthy volunteers, pronounced airway inflammation was detected following exposure to diesel exhaust (DE). The present study was conducted in order to evaluate the time kinetics of the inflammatory response following exposure to DE using induced sputum from healthy volunteers. Fifteen healthy nonsmoking volunteers were exposed to DE particles with a 50% cut-off aerodynamic diameter of 10 microm 300 microg x m(-3) and air for 1 h on two separate occasions. Sputum induction with hypertonic saline was performed 6 and 24 h after each exposure. Analyses of sputum differential cell counts and soluble protein concentrations were performed. Six hours after exposure to DE, a significant increase was found in the percentage of sputum neutrophils (37.7 versus 26.2% p=0.002) together with increases in the concentrations of interleukin-6 (12.0 versus 6.3 pg x mL(-1), p=0.006) and methylhistamine (0.11 versus 0.12 microg x L(-1), p=0.024). Irrespective of exposure, a significant increase was found in the percentage of sputum neutrophils at 24 as compared to 6 h, indicating that the procedure of sputum induction itself may change the composition of sputum. This study demonstrates that exposure to diesel exhaust induces inflammatory response in healthy human airways, represented by an early increase in interleukin-6 and methylhistamine concentration and the percentage of neutrophils. Induced sputum provides a safe tool for the investigation of the inflammatory effects of diesel exhaust, but care must be taken when interpreting results from repeated sputum inductions.
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| 32. |
- Nordenhäll, C, et al.
(författare)
-
Diesel exhaust enhances airway responsiveness in asthmatic subjects
- 2001
-
Ingår i: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 17:5, s. 909-915
-
Tidskriftsartikel (refereegranskat)abstract
- Particulate matter (PM) pollution has been associated with negative health effects, including exacerbations of asthma following exposure to PM peaks. The aim of the present study was to investigate the effects of short-term exposure to diesel exhaust (DE) in asthmatics, by specifically addressing the effects on airway hyperresponsiveness, lung function and airway inflammation. Fourteen nonsmoking, atopic asthmatics with stable disease, on continuous treatment with inhaled corticosteroids, were included. All were hyperresponsive to methacholine. Each subject was exposed to DE (particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) 300 microg x m(-3)) and air during 1 h on two separate occasions. Lung function was measured before and immediately after the exposures. Sputum induction was performed 6 h, and methacholine inhalation test 24 h, after each exposure. Exposure to DE was associated with a significant increase in the degree of hyperresponsiveness, as compared to after air, of 0.97 doubling concentrations at 24 h after exposure (p < 0.001). DE also induced a significant increase in airway resistance (p=0.004) and in sputum levels of interleukin (IL)-6 (p=0.048). No changes were detected in sputum levels of methyl-histamine, eosinophil cationic protein, myeloperoxidase and IL-8. This study indicated that short-term exposure to diesel exhaust, equal to high ambient levels of particulate matter, is associated with adverse effects in asthmatic airways, even in the presence of inhaled corticosteroid therapy. The increase in airway responsiveness may provide an important link to epidemiological findings of exacerbations of asthma following exposure to particulate matter.
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| 33. |
- Olofsson, Sven-Olof, 1947, et al.
(författare)
-
Triglyceride containing lipid droplets and lipid droplet-associated proteins.
- 2008
-
Ingår i: Current opinion in lipidology. - 0957-9672. ; 19:5, s. 441-7
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE OF REVIEW: Cytosolic lipid droplets are now recognized as dynamic organelles. This review summarizes our current understanding of the mechanisms involved in the formation of lipid droplets, the importance of lipid droplet-associated proteins and the link between lipid droplet accumulation and development of insulin resistance. RECENT FINDINGS: Lipid droplets are formed as primordial droplets and they increase in size by fusion. This fusion process requires the alpha-soluble N-ethylmaleimide-sensitive factor adaptor protein receptor SNAP23, which is also involved in the insulin-dependent translocation of a glucose transporter to the plasma membrane. Recent data suggest that SNAP23 is the link between increased lipid droplet accumulation and development of insulin resistance. Lipid droplets also form tight interactions with other organelles. Furthermore, additional lipid droplet-associated proteins have been identified and shown to play a role in droplet assembly and turnover, and in sorting and trafficking events. SUMMARY: Recent studies have identified a number of key proteins that are involved in the formation and turnover of lipid droplets, and SNAP23 has been identified as a link between accumulation of lipid droplets and development of insulin resistance. Further understanding of lipid droplet biology could indicate potential therapeutic targets to prevent accumulation of lipid droplets and associated complications.
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| 34. |
- Paal, D Molander, et al.
(författare)
-
Harmonized Nordic strategies for isocyanate monitoring in workroom atmospheres
- 2002
-
Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 685-687
-
Tidskriftsartikel (refereegranskat)abstract
- The Nordic Network on Isocyanates (NORDNI) is financed by the Nordic Council of Ministers and is under the administration of Prof. Yngvar Thomassen and co-workers. National Institute of Occupational Health, Norway. The aim of NORDNI is to establish a broad network between the Nordic National Institutes of Occupational Health working within the field of isocyanate exposure and strategies for sampling and determination of isocyanates in workroom atmospheres. This viewpoint article summarizes the resolutions that were established at the 1st NORDNI consensus meeting arranged in Frøya, Norway, 31st August-2nd September, 2001. The consensus platform from the 1st NORDNI meeting was presented at the 4th International Symposium on Modern Principles of Air Monitoring, Lillehammer, Norway, 3-7 February, 2002.
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| 35. |
- Sandström, K. J. Mattias, et al.
(författare)
-
Amperometric biosensor for formic acid in air
- 2000
-
Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 70:1–3, s. 182-187
-
Tidskriftsartikel (refereegranskat)abstract
- The possibility of developing a simple, inexpensive and specific personal passive “real-time” air sampler incorporating a biosensor for formic acid was investigated. The sensor is based on the enzymatic reaction between formic acid and formate dehydrogenase (FDH) with nicotinamide adenine dinucleotide (NAD+) as a co-factor and Meldola's blue as mediator. An effective way to immobilise the enzyme, co-factor and Meldola's blue on screen-printed, disposable, electrodes was found to be in a mixture of glycerol and phosphate buffer covered with a gas-permeable membrane. Steady-state current was reached after 4–15 min and the limit of detection was calculated to be below 1 mg/m3. However, the response decreased by 50% after storage at −15°C for 1 day.
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| 36. |
- Sandström, K. J. Mattias, et al.
(författare)
-
Multivariate evaluation of factors influencing the performance of a formic acid biosensor for use in air monitoring
- 2001
-
Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 126:11, s. 2008-2014
-
Tidskriftsartikel (refereegranskat)abstract
- A formic acid biosensor for air monitoring has been evaluated using chemometric methods. Using experimental design eleven factors that could influence the performance of the biosensor were examined. The response matrices consisted of six parameters (steady state currents at three different formic acid concentrations and response rates during changes in formic acid concentrations) describing the performance of the biosensor. The data were evaluated using a combination of principal component analysis (PCA) and multiple linear regression (MLR). To confirm the conclusions from the PCA-MLR partial least squares (PLS) was also used. The most important factor for the biosensor performance was found to be the enzyme concentration. Using the information from the chemometric analyses the optimum operation conditions for the biosensor were determined. The steady state currents were increased by 18-30% and the initial two response rates increased by 47-89% compared with a biosensor that had not been optimised.
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| 37. |
- Schulte-Ladbeck, Rasmus, et al.
(författare)
-
Characterization of chemical interferences in the determination of unsaturated aldehydes using aromatic hydrazine reagents and liquid chromatography
- 2001
-
Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 3:3, s. 306-310
-
Tidskriftsartikel (refereegranskat)abstract
- A systematic investigation on interferences in the determination of unsaturated aldehydes and ketones using the 2,4-dinitrophenylhydrazine (DNPH) method is described. Acrolein, crotonaldehyde, methacrolein and 1-buten-3-one are derivatized with DNPH in the presence of an acidic catalyst to form the respective hydrazones. The unstable hydrazones react with excess reagent to form adducts. These are identified by high-performance liquid chromatography (HPLC)-mass spectrometry and spectroscopic techniques after cryogenic fraction collection of the adducts. The quantification of the unsaturated carbonyls with the DNPH method remains difficult. N-Methyl-4-hydrazino-7-nitrobenzofurazan (MNBDH) was used as an alternative reagent for this purpose. As with DNPH, the formation of a side product is observed. In contrast to DNPH, the alteration of the pH immediately after sampling leads to only one reaction product, which is stable and storable in solution at 4 degrees C for 2 days.
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| 38. |
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| 39. |
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| 40. |
- Strandberg, Bo, 1960, et al.
(författare)
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Field evaluation of two diffusive samplers and two adsorbent media to determine 1,3-butadiene and benzene levels in air
- 2006
-
Ingår i: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 40:40, s. 7686-7695
-
Tidskriftsartikel (refereegranskat)abstract
- Two types of diffusive samplers, both of which are compatible with thermal desorption, but differ in their geometry-SKC-Ultra (badge-type) and Radiello (radial symmetry-type)-were evaluated indoors and outdoors under varying temperature, humidity and wind speed conditions, using the graphitized adsorbents Carbopack X or Carbograph 5 to measure 1,3-butadiene and benzene in ambient air. The results obtained by diffusive sampling were compared with results obtained using a conventional active sampling method over both long (1 week) and shorter periods (6-24 h). Analysis and detection were performed using an automatic thermal desorber (ATD) connected to a gas chromatograph-flame ionization detector (GC/FID). Results from each sampler and adsorbent combination were examined using ordinary or multiple linear regression analysis. The overall uncertainty (OU) was also determined. In general, the results obtained with both samplers showed good agreement with those obtained by active sampling. Carbopack X appeared to be a more efficient adsorbent than Carbograph 5 for 1,3-butadiene, but the two adsorbents were equivalent for benzene. No effects of either humidity or air velocity were observed. Minor temperature effects were observed for both samplers for 1,3-butadiene. In summary, the results confirmed the accuracy of sampling rates previously determined for the two samplers and adsorbents. We consider the two samplers to be suitable for stationary and personal monitoring for the general population of 1,3-butadiene and benzene in various environments, indoors and outdoors. They are almost independent of meteorological conditions and may be suitable for monitoring industrial atmospheres.
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| 41. |
- Sunesson, Anna-Lena, et al.
(författare)
-
Passive sampling in combination with thermal desorption and gas chromatography as a tool for self-assessment of chemical exposure
- 2002
-
Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 706-710
-
Tidskriftsartikel (refereegranskat)abstract
- Diffusive samplers for monitoring of air quality are user-friendly devices that can normally be operated by the user himself. Hence these samplers are suitable for self-assessment. Practical and work organisational aspects of self-assessment of chemical exposure were studied in different occupational settings. It was found that the diffusive sampler used in these studies, the Perkin-Elmer tube in combination with thermal desorption, worked well for the purpose and could be correctly handled by the individuals using it. The results from self-assessments agreed well with expert measurements carried out by an occupational hygienist. However, in order to obtain a sustainable system of self-assessment strong organizational support is needed.
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| 42. |
- von Zweigbergk, Peter, et al.
(författare)
-
Development of a diffusive sampling method for determination of methyl isocyanate in air
- 2002
-
Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 663-666
-
Tidskriftsartikel (refereegranskat)abstract
- A diffusive sampling method for determination of methyl isocyanate in air has been developed. A glass fibre filter impregnated with 1-(2-methoxyphenyl)piperazine in a commercially available diffusive sampling device was used to collect methyl isocyanate and the derivative formed was analysed with LC-MS/MS. The sampling rate was determined to be 15.6 ml min(-1), with a relative standard deviation of 7.3%. The sampler was validated for sampling periods from 15 min to 8 h, for relative humidities from 20% to 80% and for concentrations from I to 46 microg m(-3). A field validation was also made and the diffusive sampling results showed no difference compared to a pumped reference method. The impregnated filters have to be stored apart from the diffusive sampler housing and loaded into the sampler prior to each sampling.
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| 43. |
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