| 1. |
- Isaksson, Marléne, et al.
(författare)
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Patch Testing with Formaldehyde 2.0% in Parallel with 1.0% by the Swedish Contact Dermatitis Research Group
- 2014
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Ingår i: Acta Dermato-Venereologica. - : Taylor & Francis. - 0001-5555 .- 1651-2057. ; 94:4, s. 408-410
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Tidskriftsartikel (refereegranskat)abstract
- In a multicentre study consecutively patch-tested dermatitis patients were tested simultaneously with 1.0% and 2.0% (w/v) formaldehyde in aqua applied with a micro-pipette (15 mu l) to the filter paper disc in Finn Chambers (0.30 mg/cm(2) and 0.60 mg/cm(2), respectively). A total of 2,122 dermatitis patients were patch-tested. In all, 77 (3.6%) patients reacted positively to formaldehyde; 37 reacted only to 2.0%, 35 reacted to both concentrations and 5 patients reacted only to 1.0%. Significantly more patients were thus diagnosed with contact allergy to formaldehyde with 2.0% compared to 1.0% (p<0.001) without causing more irritant reactions. The detected number of isolated allergic reactions to the 2 formaldehyde-releasers in the Swedish baseline series and not to formaldehyde itself raises the question whether quaternium-15 1.0% and diazolidinyl urea 2.0% should be present in the Swedish baseline series.
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| 2. |
- Almstrand, Robert, et al.
(författare)
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Three-dimensional stratification of bacterial biofilm populations in a moving bed biofilm reactor for nitritation-anammox.
- 2014
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 15:2, s. 2191-206
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Tidskriftsartikel (refereegranskat)abstract
- Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers.
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| 3. |
- Andersson Chan, Anneli, 1971-, et al.
(författare)
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Increased nitrogen removal in existing volumes at Sundet wastewater treatment plant, Växjö
- 2014
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Ingår i: Water practice and technology. - : IWA Publishing. - 1751-231X. ; 9:2, s. 215-224
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Tidskriftsartikel (refereegranskat)abstract
- Many wastewater treatment plants need to improve their nitrogen removal due to stricter requirements and increasing loads. This often means larger bioreactor volumes, which can be very expensive and is sometimes impossible if space is limited. Therefore, there is a need for compact hybrid solutions that can increase capacity within existing volumes. Two full-scale demonstration projects using moving bed biofilm reactor (MBBR) technology has proven to be an efficient way to treat nitrogen in existing volumes at Sundet wastewater treatment plant in Växjö. Increased nitrification and denitrification capacity in parts of the main stream were demonstrated through the Hybas™ process, a combination of MBBR and activated sludge using the integrated fixed-film activated sludge technology. The ANITA™ Mox process, using autotrophic N-removal through anaerobic ammonium oxidation (anammox), provided high nitrogen removal for the sludge liquor. Data collected on-site for over a year are analyzed and compared with the performance of conventional treatment systems. These two full-scale demonstration projects have been a successful learning experience in identifying and correcting both process and operational issues, which may not have arisen at pilot scale. The set objectives in terms of nitrogen removal were met for both processes and design modifications have been identified that will improve future operation at Sundet WWTP.
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| 4. |
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| 5. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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Air-oxidized linalool: a frequent cause of fragrance contact allergy.
- 2012
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 67:5, s. 247-259
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Tidskriftsartikel (refereegranskat)abstract
- Background. Linalool is a common fragrance terpene that, in pure form, is not allergenic or is a very weak allergen. However, linalool autoxidizes on air exposure, and the oxidation products can cause contact allergy. In a Swedish study, oxidized linalool 6.0% in petrolatum (pet.) gave 5% positive patch test reactions in 2500 dermatitis patients. Objectives. To investigate whether oxidized linalool 6%, with a stable concentration of the main haptens, the linalool hydroperoxides (Lin-OOHs) in pet., could be a useful tool for the detection of contact allergy in an international setting. Methods. Oxidized linalool 6.0% (Lin-OOHs 1%) pet. was tested in 2900 consecutive dermatitis patients in Denmark, the United Kingdom, Singapore, Spain, Sweden, and Australia. Results. Overall, 6.9% (range 3–13%) of the patients showed positive patch test reactions to oxidized linalool. Doubtful reactions were found in 9.2% of the patients (range 0–36%). Few irritant reactions were seen. Conclusions. In an international setting, oxidized linalool has been shown to be a common allergen. Oxidized linalool 6.0% (Lin-OOHs 1%) pet. is a useful, standardized and stable tool for the detection of contact allergy in dermatitis patients. Many patients showing positive patch test reactions to oxidized linalool would not have been informed of their fragrance allergy if this specific test had not been performed
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| 6. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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An international multicentre study on the allergenic activity of air-oxidized R-limonene
- 2013
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873. ; 68:4, s. 214-223
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Tidskriftsartikel (refereegranskat)abstract
- Background. Limonene is a common fragrance terpene that, in its pure form, is not allergenic or is a very weak allergen. However, limonene autoxidizes on air exposure, and the oxidation products can cause contact allergy. Oxidized R-limonene has previously been patch tested in multicentre studies, giving 2–3% positive patch test reactions in consecutive patients. Objectives. To investigate whether oxidized R-limonene 3.0% in petrolatum, with a stable concentration of the main haptens, limonene hydroperoxides (Lim-OOHs), could be a useful tool for the detection of contact allergy in an international setting. Methods. Oxidized R-limonene 3.0% (Lim-OOHs 0.33%) pet. was tested in 2900 consecutive dermatitis patients in Denmark, the United Kingdom, Singapore, Spain, Sweden, and Australia. Results. Overall, 5.2% (range 2.3–12.1%) of the patients showed a positive patch test reaction to oxidized R-limonene. Doubtful reactions were found in 7.0% of the patients (range 0–24%). Few irritant reactions were seen. Conclusions. Oxidized R-limonene at 3.0% pet. with a specified content of Lim-OOHs 0.33% is a standardized and useful tool for the detection of contact allergy in dermatitis patients. Many patients showing positive patch test reactions to oxidized R-limonene would not be informed of their fragrance allergy if this specific test had not been performed.
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| 7. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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Linalool - a significant contact sensitizer after air exposure
- 2010
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 62:1, s. 32-41
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Tidskriftsartikel (refereegranskat)abstract
- Background: Linalool is a widely used fragrance terpene. Pure linalool is not allergenic or a very weak allergen, but autoxidizes on air exposure and the oxidation products can cause contact allergy. Oxidized (ox.) linalool has previously been patch tested at a concentration of 2.0% in petrolatum (pet.) in 1511 patients, and 1.3% positive patch test reactions were observed. Objective: To investigate the optimal patch test concentration for detection of contact allergy to ox. linalool. Methods: Four concentrations of ox. linalool (2.0%, 4.0%, 6.0%, 11.0% pet.) were tested in 3418 consecutive dermatitis patients. Results: Ox. linalool 2.0%, 4.0%, 6.0%, and 11.0% pet. detected positive patch test reactions in 0.83%, 3.2%, 5.3%, and 7.2% of the tested patients, respectively. The doubtful reactions increased with rising concentrations but relatively less, giving 5.1%, 6.4%, and 7.3% doubtful reactions, respectively, for ox. linalool 4.0%, 6.0%, and 11.0% pet. Few irritative reactions were seen. Conclusions: Raising the patch test concentration for ox. linalool gave a better detection of contact allergy, as many as 5-7% positive patch test reactions were detected. We suggest a patch test concentration of ox. linalool 6.0% pet. for future patch testing, giving a dose per unit area of 2.4 mg/cm(2) when 20 mg test substance is tested in small Finn Chambers (R).
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| 8. |
- Bråred Christensson, Johanna, 1965, et al.
(författare)
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Positive patch test reactions to oxidized limonene: exposure and relevance
- 2014
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 71:5, s. 264-272
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Tidskriftsartikel (refereegranskat)abstract
- Background. R-Limonene is a common fragrance terpene found in domestic and industrial products. R-Limonene autoxidizes on air exposure, and the oxidation products can cause contact allergy. In a recent multicentre study, 5.2% (range 2.3-12.1%) of 2900 patients showed a positive patch test reaction to oxidized R-limonene. Objective. To study the exposure to limonene among consecutive dermatitis patients reacting to oxidized R-limonene in an international setting, and to assess the relevance of the exposure for the patients' dermatitis. Methods. Oxidized R-limonene 3.0% (containing limonene hydroperoxides at 0.33%) in petrolatum was tested in 2900 consecutive dermatitis patients in Australia, Denmark, the United Kingdom, Singapore, Spain, and Sweden. A questionnaire assessing exposure to limonene-containing products was completed. Results. Overall, exposure to products containing limonene was found and assessed as being probably relevant for the patients' dermatitis in 36% of the limonene-allergic patients. In Barcelona and Copenhagen, >70% of the patients were judged to have had an exposure to limonene assessed as relevant. Conclusions. Oxidized R-limonene is a common fragrance allergen, and limonene was frequently found in the labelling on the patients' products, and assessed as relevant for the patients' dermatitis. A large number of domestic and occupational sources for contact with R-limonene were identified.
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| 9. |
- Christensson, Magnus, et al.
(författare)
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Experience from start-ups of the first ANITA Mox Plants
- 2013
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 67:12, s. 2677-2684
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Tidskriftsartikel (refereegranskat)abstract
- ANITA (TM) Mox is a new one-stage deammonification Moving-Bed Biofilm Reactor (MBBR) developed for partial nitrification to nitrite and autotrophic N-removal from N-rich effluents. This deammonification process offers many advantages such as dramatically reduced oxygen requirements, no chemical oxygen demand requirement, lower sludge production, no pre-treatment or requirement of chemicals and thereby being an energy and cost efficient nitrogen removal process. An innovative seeding strategy, the 'BioFarm concept', has been developed in order to decrease the start-up time of new ANITA Moxinstallations. New ANITA Mox installations are started with typically 3-15% of the added carriers being from the 'BioFarm', with already established anammox biofilm, the rest being new carriers. The first ANITA Mox plant, started up in 2010 at Sjolunda wastewater treatment plant (WWTP) in Malmo, Sweden, proved this seeding concept, reaching an ammonium removal rate of 1.2 kgN/m(3) d and approximately 90% ammonia removal within 4 months from start-up. Thisfirst ANITA Mox plant is also the BioFarm used for forthcoming installations. Typical features of this first installation were low energy consumption, 1.5 kW/NH4-N-removed, low N2O emissions, <1% of the reduced nitrogen and a very stable and robust process towards variations in loads and process conditions. The second ANITA Mox plant, started up at Sundets WWTP in Vaxjo, Sweden, reached full capacity with more than 90% ammonia removal within 2 months from start-up. By applying a nitrogen loading strategy to the reactor that matches the capacity of the seeding carriers, more than 80% nitrogen removal could be obtained throughout the start-up period.
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| 10. |
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