| 1. |
- Zhang, Renyun, et al.
(författare)
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Soap-film coating : High-speed deposition of multilayer nanofilms
- 2013
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Ingår i: Scientific Reports. - Nature Publishing Group : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. Art. no. 1477-
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Tidskriftsartikel (refereegranskat)abstract
- The coating of thin films is applied in numerous fields and many methods are employed for the deposition of these films. Some coating techniques may deposit films at high speed; for example, ordinary printing paper is coated with micrometre-thick layers of clay at a speed of tens of meters per second. However, to coat nanometre thin films at high speed, vacuum techniques are typically required, which increases the complexity of the process. Here, we report a simple wet chemical method for the high-speed coating of films with thicknesses at the nanometre level. This soap-film coating technique is based on forcing a substrate through a soap film that contains nanomaterials. Molecules and nanomaterials can be deposited at a thickness ranging from less than a monolayer to several layers at speeds up to meters per second. We believe that the soap-film coating method is potentially important for industrial-scale nanotechnology.
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| 2. |
- Blind, Per-Jonas, et al.
(författare)
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Fast-Track Program for Liver Resection - Factors Prolonging Length of Stay
- 2014
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Ingår i: Hepato-Gastroenterology. - 0172-6390. ; 61:136, s. 2340-2344
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Fast-track programs involving multi-modal measures to enhance recovery after surgery, reduce morbidity and decrease hospital length of stay (LOS) are used for different major surgical procedures. For liver resections, factors influencing LOS within a fast-track program have been studied only to a limited extent, which was the aim of the present study. Methodology: The present study comprises the first 64 patients included in a fast-track program for liver resections introduced in March 2012. Patient outcomes were compared to a historical cohort of patients (n=62) operated in 2009. Factors prolonging LOS was analyzed by uni- and multivariate analysis. Results: Median LOS was 6 days (range 3-42 days) within the fast-track program as compared with 8 days (range 5-47 days) in the historical cohort (P=0.004). On multivariate analysis, factors increasing LOS in the fast-track group were found to be the presence of complication (P=0.018), extent of resection (major as compared to minor) (P=0.001) and inability to drink > 1250 ml on the day after surgery (P=0.002). Conclusion: Patients who can only drink limited amounts of fluid the day after-liver resection represent a subset of patients that should be given special attention within a fast-track program.
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| 3. |
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| 4. |
- Johansson, Robert, et al.
(författare)
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Tailored vs. Standardized Internet-Based Cognitive Behavior Therapy for Depression and Comorbid Symptoms: A Randomized Controlled Trial
- 2012
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Ingår i: PLOS ONE. - San Francisco : Public Library of Science. - 1932-6203. ; 7:5
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: Major depression can be treated by means of cognitive behavior therapy, delivered via the Internet as guided self-help. Individually tailored guided self-help treatments have shown promising results in the treatment of anxiety disorders. This randomized controlled trial tested the efficacy of an Internet-based individually tailored guided self-help treatment which specifically targeted depression with comorbid symptoms. The treatment was compared both to standardized (non-tailored) Internet-based treatment and to an active control group in the form of a monitored online discussion group. Both guided self-help treatments were based on cognitive behavior therapy and lasted for 10 weeks. The discussion group consisted of weekly discussion themes related to depression and the treatment of depression. Methods: A total of 121 participants with diagnosed major depressive disorder and with a range of comorbid symptoms were randomized to three groups. The tailored treatment consisted of a prescribed set of modules targeting depression as well as comorbid problems. The standardized treatment was a previously tested guided self-help program for depression. Results: From pre-treatment to post-treatment, both treatment groups improved on measures of depression, anxiety and quality of life. The results were maintained at a 6-month follow-up. Subgroup analyses showed that the tailored treatment was more effective than the standardized treatment among participants with higher levels of depression at baseline and more comorbidity, both in terms of reduction of depressive symptoms and on recovery rates. In the subgroup with lower baseline scores of depression, few differences were seen between treatments and the discussion group. Conclusions: This study shows that tailored Internet-based treatment for depression is effective and that addressing comorbidity by tailoring may be one way of making guided self-help treatments more effective than standardized approaches in the treatment of more severe depression.
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| 5. |
- Neuman, Åsa, et al.
(författare)
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Infant wheeze, comorbidities and school age asthma
- 2014
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Ingår i: Pediatric Allergy and Immunology. - : Wiley. - 0905-6157 .- 1399-3038. ; 25:4, s. 380-386
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Tidskriftsartikel (refereegranskat)abstract
- Background: Factors associated with early onset of wheeze have been described, but there is limited knowledge on which of these infant wheezers who will have developed asthma in school age. The aim was to identify clinical risk factors for asthma in the 8-yr-old children that wheezed during infancy in a population-based setting. Methods: Three thousand two hundred and fifty-one children from a population-based birth cohort followed prospectively from infancy until age 8 yr were included in the study. Data were analyzed using multivariate logistic regression analysis. Results: Parents reported any wheeze episode before age 2 yr in 823 subjects (25%). Infant wheezers had an almost fourfold risk of asthma at age 8 [adjusted odds ratio (aOR) 3.68, 95% CI 2.74-4.96], equivalent to an asthma prevalence of 14% compared with 4% among non-wheezers (p < 0.001). After adjustments for sex, exposure to tobacco smoke and indoor dampness/mould, allergic heredity (aOR 1.53, 95% CI 1.02-2.30), increased frequency of wheeze (aOR 3.41, 95% CI 2.09-5.56 for children with >= 3 episodes compared with <= 2 episodes during the first 2 yr of life), infant eczema (aOR 2.31, 95% CI 1.52-3.49), and recurrent abdominal pain (aOR 2.33, 95% CI 1.30-4.16) remained risk factors for school age asthma in the infant wheezing group. Conclusions: Among infant wheezers, allergic heredity, increased severity of wheeze, infant eczema, and recurrent abdominal pain were independent risk factors for asthma at age 8 yr. Among children with three or four of these risk factors, 38% had asthma at school age.
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| 6. |
- Nilsson, Anna, et al.
(författare)
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Frequent detection of respiratory agents by multiplex PCR on oropharyngeal samples in Swedish school-attending adolescents
- 2012
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 44, s. 393-397
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Tidskriftsartikel (refereegranskat)abstract
- Background: Respiratory agents may be detected in the oropharynx of healthy individuals. The extent of this condition and the reasons behind it are largely unknown. The objective of this study was to determine the factors associated with the presence of respiratory agents in the oropharynx of adolescents healthy enough to attend school activities. Methods: On a single day in December, samples from the posterior wall of the oropharynx of adolescents aged 1015 y were obtained using cotton-tipped swabs. The samples were analyzed by real-time polymerase chain reaction (PCR) for the presence of 13 respiratory viruses and 2 bacteria (Mycoplasma pneumoniae and Chlamydophila pneumoniae). Results: Out of the 232 adolescents sampled, 67 (29%) had any respiratory symptom. A positive PCR result was found in 50 individuals (22%). Human rhinovirus was the most commonly found agent. Respiratory agents were significantly more frequent in the younger age group (1013 y) than in the older age group (1415 y): 26% (38/148) vs 14% (12/84), respectively; p = 0.04. Cough was the only symptom that was more common among individuals with a positive PCR test than among those with a negative PCR test: 8/50 (16%) vs 11/182 (6%); p = 0.02. Family size and class size were not associated with the likelihood of a positive PCR test. Conclusions: The presence of respiratory agents in the oropharynx is a frequent finding among adolescents healthy enough to attend school activities. The high prevalence was found to be associated with young age, but not with the size of the family or class. © 2012 Informa Healthcare.
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| 7. |
- Nilsson, Magnus, et al.
(författare)
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A 9-band WCDMA/EDGE transceiver supporting HSPA evolution
- 2011
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Ingår i: [Host publication title missing]. - 0193-6530. ; , s. 366-368
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Konferensbidrag (refereegranskat)abstract
- The future of cellular radio ICs lies in the integration of an ever-increasing number of bands and channel bandwidths. This paper presents a transceiver together with the associated discrete front-end components. The transceiver supports 4 EDGE bands and 9 WCDMA bands (l-VI and Vlll-X), while the radio can be configured to simultaneously support the 4 EDGE bands and up to 5 WCDMA bands: 3 high bands (HB) and 2 low bands (LB). The RX is a SAW-less homodyne composed of a main RX and a diversity RX. To reduce package complexity with so many bands, we chose to minimize the number of ports by using single-ended RF interfaces for both RX and TX. This saves seve ral package pins, but requires careful attention to grounding. The main RX has 8 LNA ports and the diversity RX has 5, with some LNAs supporting multiple bands. On the TX side, 2 ports are used for all EDGE bands and 4 for the WCDMA bands.
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| 8. |
- Sun, Xiaole, 1983-, et al.
(författare)
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Stable silicon isotope analysis on nanomole quantities using MC-ICP-MS with a hexapole gas-collision cell
- 2010
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Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 25:2, s. 156-162
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate in this study that a single focusing multiple collector inductively coupled plasma massspectrometer (MC-ICP-MS) equipped with a hexapole gas-collision cell (GV-instrument Isoprobe) canprecisely determine the d29Si (2S.D., 0.2&) using a total Si consumption of less than 14 nmole (390 ngSi). Testing and evaluation of background, rinse time, and major matrix effects have been performed ina systematic way to establish a procedure to measure d29Si in small quantities. Chemical purificationprior to analysis is required to remove potential interferences. For data collected during a four-yearperiod, the average d29Si value of IRMM-018 relative to NBS-28 was found to be 0.95& (n ¼ 23,2S.D. 0.16&) with a 95% confidence interval (0.95 0.028&). The mean d29Si value of the Big-Batchstandard was found to be 5.50& (n ¼ 6, 2S.D. 0.26&). Although determination of the d30Simeasurements is not possible, with our current instrument we demonstrate that this system providesa fast and long-term reliable method for the analysis of d29Si in purified samples with low Siconcentration (18 mM Si).
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| 9. |
- Tjärnhage, Torbjörn, et al.
(författare)
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Development of a laser-induced breakdown spectroscopy instrument for detection and classification of single particle aerosols in real-time
- 2013
-
Ingår i: Optics Communications. - Amsterdam : Elsevier. - 0030-4018 .- 1873-0310. ; 296, s. 106-108
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Tidskriftsartikel (refereegranskat)abstract
- Detection of aerosolized biological warfare agents by means of LIBS commonly operate with pulsed lasers running at constant repetition rate, resulting in very low hit rates. In this paper, we present a prototype where the LIBS laser is only fired if a particle is expected in the focal zone. A significantly improved hit rate for detection and classification of μm sized single particles in real-time is achieved. Hit rates of 40% and 70% for NaCl particles of sizes 3 and 7.0μm, respectively, can be reached in triggered configuration, as compared to 1% and 2% when the laser is un-triggered.
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| 10. |
- Wang-Hansen, Carolin, 1982, et al.
(författare)
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Characterization of particulate matter from direct injected gasoline engines
- 2013
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Ingår i: Topics in Catalysis. - : Springer Science and Business Media LLC. - 1572-9028 .- 1022-5528. ; 56:1-8, s. 446-451
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Tidskriftsartikel (refereegranskat)abstract
- The reactivity and reaction kinetics of particulate matter (PM) from direct injected gasoline (GDI) engines has been studied by O2 and NO2 based temperature programmed and isothermal step-response experiments, and the PM nano-structure has been characterized using HRTEM. The reactivity of the PM samples collected in filters during on-road driving was found to increase in the following order: Printex U\diesel\gasoline PI & gasoline DI\ethanol for O2 based combustion. The activation energies for O2 and NO2 based oxidation of PM collected from a GDI engine in an engine bench set-up was estimated to 146 and 71 kJ/mol respectively, which is comparable to corresponding values reported for diesel and model soot. Similar nano-structure features (crystallites plane dimensions, curvature and relative orientation) as observed for diesel soot were observed for gasoline PM.
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| 11. |
- Zhang, Renyun, et al.
(författare)
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High-speed deposition of multilayer nanofilms using soap-film coating
- 2013
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Konferensbidrag (refereegranskat)abstract
- High-speed deposition of multilayer nanofilms using soap-film coatingRenyun Zhang, Henrik A. Andersson, Mattias Andersson, Britta Andres, Per Edström, Sverker Edvardsson, Sven Forsberg, Magnus Hummelgård, Niklas Johansson, Kristoffer Karlsson, Hans-Erik Nilsson, Martin Olsen, Tetsu Uesaka, Thomas Öhlund & Håkan OlinDepartment of Applied Science and Design, Mid Sweden University, SE-85170 Sundsvall, SwedenEmail: renyun.zhang@miun.se or hakan.olin@miun.seCoating1 of thin films is of importance for making functionalized surfaces with applications in many fields from electronics to consumer packaging. To decrease the cost, large scale roll-to-roll2 coating techniques are usually done at high speed, for example, ordinary printing paper is coated at a speed of tens of meters per second by depositing micrometer thick layers of clay. However, nanometer thin films are harder to coat at high speed by wet-chemical methods, requiring special roll-to-roll vacuum techniques3 with the cost of higher complexity.Here, we report a simple wet chemical method for high-speed coating of films down to molecular thicknesses, called soap-film coating (SFC)4. The technique is based on forcing a substrate through a soap film that contains nanomaterials. In the simplest laboratory version, the films can be deposited by a hand-coating procedure set up in a couple of minutes. The method is quite general molecules or nanomaterials or sub-micrometer materials (Figure 1) with thicknesses ranging from less than a monolayer to several layers at speeds up to meters per second. The applications of soap-film coating is quite wide an we will show solar cells, electrochromic devices, optical nanoparticle crystals, and nano-film devices. We believe that the soap-film coating method is potentially important for industrial-scale nanotechnology.Fig. 1. Soap film coating of nanoparticles, layered materials, nanowires, and molecules. a sub-monolayer 240 nm silica nanoparticle (scale bar 2 µm) b monolayer c double layer. d monolayer gold nanoparticles. e single layer TiO2 nanoparticles. f sub-monolayer polystyrene (scale 2 µm), g monolayer of polystyrene. h triple-layer of polystyrene. i monolayer of Ferritin. j AFM image of <1.5 layer GO film (3 µm x 2 µm). k clay on glass (scale 2 µm). l SFC coated nanocellulose. m Absorbance spectra Rhodamine B on a glass slide. AFM of SDS layers n (2 µm x 1.5 µm) and o (20 µm x 15 µm).ReferencesTracton, A. A. Coating Technology Handbook (CRC Press, Boca Raton, 2006).Ohring, M. Materials science of thin films. (Academic press., 2001).Charles, B. Vacuum deposition onto webs, films and foils. (William Andrew, 2011).Zhang, R. Y., Andersson, H. A., Andersson, M., Andres, B., Edström, P., Edvardsson, S., Forsberg, S., Hummelgård, M., Johansson, N., Karlsson, K., Nilsson, H.-E., Olsen, M., Uesaka, T., Öhlund, T., Olin H. Soap film coating: High-speed deposition of multilayer nanofilms. Submitted.
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| 12. |
- Alling, Vanja, et al.
(författare)
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Non-conservative behavior of dissolved organic carbon across the Laptev and East Siberian Seas
- 2010
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Ingår i: Global Biogeochemical Cycles. - 0886-6236 .- 1944-9224. ; 24, s. GB4033-
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is expected to have a strong effect on the Eastern Siberian Arctic Shelf (ESAS) region, which includes 40% of the Arctic shelves and comprises the Laptev and East Siberian seas. The largest organic carbon pool, the dissolved organic carbon (DOC), may change significantly due to changes in both riverine inputs and transformation rates; however, the present DOC inventories and transformation patterns are poorly understood. Using samples from the International Siberian Shelf Study 2008, this study examines for the first time DOC removal in Arctic shelf waters with residence times that range from months to years. Removals of up to 10%–20% were found in the Lena River estuary, consistent with earlier studies in this area, where surface waters were shown to have a residence time of approximately 2 months. In contrast, the DOC concentrations showed a strong nonconservative pattern in areas with freshwater residence times of several years. The average losses of DOC were estimated to be 30%–50% during mixing along the shelf, corresponding to a first-order removal rate constant of 0.3 yr−1. These data provide the first observational evidence for losses of DOC in the Arctic shelf seas, and the calculated DOC deficit reflects DOC losses that are higher than recent model estimates for the region. Overall, a large proportion of riverine DOC is removed from the surface waters across the Arctic shelves. Such significant losses must be included in models of the carbon cycle for the Arctic Ocean, especially since the breakdown of terrestrial DOC to CO2 in Arctic shelf seas may constitute a positive feedback mechanism for Arctic climate warming. These data also provide a baseline for considering the effects of future changes in carbon fluxes, as the vast northern carbon-rich permafrost areas draining into the Arctic are affected by global warming.
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| 13. |
- Andersson K, Pernille
(författare)
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Changing the servicescape : The influence of music and self-disclosure on approach-avoidance behavior
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis is to investigate and understand the effect of a servicescape’s ambient and social conditions on consumers’ Approach/Avoidance behavior in a retail context. More specifically, this thesis investigates the effect of music (ambient stimuli) and employees’ self-disclosure (social stimuli) on consumers’ Approach/Avoidance behavior in a retail store. Paper I comprised two experiments. Experiment 1 investigated the influence of the independent variable No music/Music. Likewise, experiment 2 studied the influence of the independent variable No music/Slow-tempo music/Fast-tempo music. The dependent variables in both experiments were pleasure, arousal, and the resulting Approach/Avoidance behavior. Paper II investigated the influence of the independent variable self-disclosure. The dependent variables were Approach/Avoidance behavior, measured by pleasure, arousal, liking, satisfaction, and reciprocity. The conclusions of this thesis are that both ambient and social stimuli in a servicescape affect consumers’ internal responses, which in turn affect their behavior. Depending on the situation (type of purchase), retail (bank, supermarket, or electronic retail store), and stimuli (ambient or social), the internal and behavioral responses are different.
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| 14. |
- Berglund, Staffan, et al.
(författare)
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Delaktighet och hälsa : med ungdomar och beslutsfattare i Simrishamn mot hållbara strategier för ökad egenmakt, livskvalitet och jämlikhet i hälsa
- 2011
-
Rapport (refereegranskat)abstract
- Trots att vi lever i ett välfärdssamhälle, där kunskap och resurser inte borde vara något problem, ser vi en bestående ojämlikhet i hälsa och en ökande psykosocial ohälsa bland ungdomar. Hur är detta möjligt och vad kan man göra åt det? Genom vilka sociala interventioner och andra insatser kan unga människors reella delaktighet, egenmakt, välfärd, livskvalitet och hälsa främjas på ett hållbart sätt? Denna rapport från en pilotstudie genomförd i Simrishamn presenterar de teoretiska och empiriska bevekelsegrunderna för hur och varför en deltagarbaserad aktionsforskningsansats skulle kunna vara ett bra sätt att arbeta för att förbättra villkoren för ungdomars hälsa. Rapporten förespråkar dels ett ökat tvärvetenskapligt och professionsöverskridande samarbete mellan forskare och beslutsfattare, dels ett nära samarbete med ungdomarna själva. Det handlar om att få till stånd ett mer jämlikt utbyte av kunskap målgrupper och makthavare emellan – och därmed förhoppningsvis ett i längden mer jämlikt inflytande över användningen av samhällets resurser.
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| 15. |
- Berglund, Staffan, et al.
(författare)
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Delaktighet och hälsa : med ungdomar och beslutsfattare i Simrishamn mot hållbara strategier för ökad egenmakt, livskvalitet och jämlikhet i hälsa
- 2011
-
Bok (populärvet., debatt m.m.)abstract
- Trots att vi lever i ett välfärdssamhälle, där kunskap och resurser inte borde vara något problem, ser vi en bestående ojämlikhet i hälsa och en ökande psykosocial ohälsa bland ungdomar. Hur är detta möjligt och vad kan man göra åt det? Genom vilka sociala interventioner och andra insatser kan unga människors reella delaktighet, egenmakt, välfärd, livskvalitet och hälsa främjas på ett hållbart sätt? Denna rapport från en pilotstudie genomförd i Simrishamn presenterar de teoretiska och empiriska bevekelsegrunderna för hur och varför en deltagarbaserad aktionsforskningsansats skulle kunna vara ett bra sätt att arbeta för att förbättra villkoren för ungdomars hälsa. Rapporten förespråkar dels ett ökat tvärvetenskapligt och professionsöverskridande samarbete mellan forskare och beslutsfattare, dels ett nära samarbete med ungdomarna själva. Det handlar om att få till stånd ett mer jämlikt utbyte av kunskap målgrupper och makthavare emellan – och därmed förhoppningsvis ett i längden mer jämlikt inflytande över användningen av samhällets resurser.
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| 16. |
- Berglund, Staffan, et al.
(författare)
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Delaktighet och hälsa: med ungdomar och beslutsfattare mot hållbara strategier för ökad egenmakt, livskvalitet och jämlikhet i hälsa : Delrapport 1: Utgångspunkter för en deltagarbaserad aktionsforskningsansats
- 2011
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Trots att vi lever i ett välfärdssamhälle, där kunskap och resurser inte borde vara något problem, ser vi en bestående ojämlikhet i hälsa och en ökande psykosocial ohälsa bland ungdomar. Hur är detta möjligt och vad kan man göra åt det? Genom vilka sociala interventioner och andra insatser kan unga människors reella delaktighet, egenmakt, välfärd, livskvalitet och hälsa främjas på ett hållbart sätt? Denna rapport från en pilotstudie genomförd i Simrishamn presenterar de teoretiska och empiriska bevekelsegrunderna för hur och varför en deltagarbaserad aktionsforskningsansats skulle kunna vara ett bra sätt att arbeta för att förbättra villkoren för ungdomars hälsa. Rapporten förespråkar dels ett ökat tvärvetenskapligt och professionsöverskridande samarbete mellan forskare och beslutsfattare, dels ett nära samarbete med ungdomarna själva. Det handlar om att få till stånd ett mer jämlikt utbyte av kunskap målgrupper och makthavare emellan – och därmed förhoppningsvis ett i längden mer jämlikt inflytande över användningen av samhällets resurser.
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| 17. |
- Bounechada, Djamela, 1984, et al.
(författare)
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Vibrational Study of SOx Adsorption on Pt/SiO2
- 2014
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:51, s. 29713-29723
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Tidskriftsartikel (refereegranskat)abstract
- The formation of ad-SOx species on Pt/SiO2 upon exposure to SO2 in concentrations rang- ing from 10 to 50 ppm at between 200 and 400◦C has been studied by in situ diffuse reflectance infrared Fourier transformed spectroscopy. In parallel, first-principles calculations have been carried out to consolidate the experimental interpretations. It was found that sulfate species form on the silica surface with a concomitant removal/ rearrangement of silanol groups. For- mation of ad-SOx species occurs only after SO2 oxidation to SO3 on the platinum surface. Thus SO2 oxidation to SO3 is the first step in the SOx adsorption process, followed by spillover of SO3 to the oxide and, finally, the formation of sulfate species on the hydroxyl positions on the oxide. The sulfate formation is influenced by both temperature and SO2 concentration. Furthermore, exposure to hydrogen is shown to be sufficiently efficient as to remove ad-SOx species from the silica surface.
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| 18. |
- Edstrom, Per, et al.
(författare)
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Geometry Related Inter-Instrument Differences in Spectrophotometric Measurements
- 2010
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 25:2, s. 221-232
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Tidskriftsartikel (refereegranskat)abstract
- The L&W Elrepho d/0 and the Spectrolino 45/0 instruments are examined using paper samples with different properties. External factors that influence the measurements such as the sample background, the instrument calibration and the sample inhomogeneity are studied, and a methodology for their minimization is presented. Experimental measurements show that such external factors, if not minimized by proper routines, affect the inter-instrument differences far more (up to 4-5 Delta E-ab(star)) than the instrument geometry (the effect of which is small and of order 0.1 Delta E-ab(star)). The DORT2002 radiative transfer model is used to simulate differences caused by instrument geometry. The simulated and measured differences are found to agree in magnitude, and the differences are mapped against sample properties. It is observed that the 45/0 instrument detects higher reflectance from paper samples with negligible absorption and transmittance. When there is considerable absorption (dyed samples) or transmittance (thin samples), the d/0 instrument detects higher reflectance. The physical mechanism behind this behavior is studied and explained using DORT2002, and the instrument differences are shown to depend on the anisotropy of the reflected light. The model/measurement agreement is satisfactory as the characteristic behavior is captured in almost all cases studied. This new understanding is important for facilitating accurate data exchange between the paper and graphic arts industries, but also for interpretation of reflectance measurements in general.
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| 19. |
- Edström, Per, et al.
(författare)
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Geometry Related Inter-Instrument Differences in Spectrophotometric Measurements
- 2010
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 25:2, s. 221-232
-
Tidskriftsartikel (refereegranskat)abstract
- The L&W Elrepho d/0 and the Spectrolino 45/0 instruments are examined using paper samples with different properties. External factors that influence the measurements such as the sample background, the instrument calibration and the sample inhomogeneity are studied, and a methodology for their minimization is presented. Experimental measurements show that such external factors, if not minimized by proper routines, affect the inter-instrument differences far more (up to 4-5 Delta E-ab(star)) than the instrument geometry (the effect of which is small and of order 0.1 Delta E-ab(star)). The DORT2002 radiative transfer model is used to simulate differences caused by instrument geometry. The simulated and measured differences are found to agree in magnitude, and the differences are mapped against sample properties. It is observed that the 45/0 instrument detects higher reflectance from paper samples with negligible absorption and transmittance. When there is considerable absorption (dyed samples) or transmittance (thin samples), the d/0 instrument detects higher reflectance. The physical mechanism behind this behavior is studied and explained using DORT2002, and the instrument differences are shown to depend on the anisotropy of the reflected light. The model/measurement agreement is satisfactory as the characteristic behavior is captured in almost all cases studied. This new understanding is important for facilitating accurate data exchange between the paper and graphic arts industries, but also for interpretation of reflectance measurements in general.
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| 20. |
- Ekerstad, Niklas, et al.
(författare)
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Frailty is independently associated with 1-year mortality for elderly patients with non-ST-segment elevation myocardial infarction
- 2014
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Ingår i: European Journal of Preventive Cardiology. - : Sage Publications. - 2047-4873 .- 2047-4881. ; 21:10, s. 1216-1224
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: For the large population of elderly patients with cardiovascular disease, it is crucial to identify clinically relevant measures of biological age and their contribution to risk. Frailty is denoting decreased physiological reserves and increased vulnerability. We analysed the manner in which the variable frailty is associated with 1-year outcomes for elderly non-ST-segment elevation myocardial infarction (NSTEMI) patients. METHODS AND RESULTS: Patients aged 75 years or older, with diagnosed NSTEMI were included at three centres, and clinical data including judgment of frailty were collected prospectively. Frailty was defined according to the Canadian Study of Health and Aging Clinical Frailty Scale. Of 307 patients, 149 (48.5%) were considered frail. By Cox regression analyses, frailty was found to be independently associated with 1-year mortality after adjusting for cardiovascular risk and comorbid conditions (hazard ratio 4.3, 95% CI 2.4-7.8). The time to the first event was significantly shorter for frail patients than for nonfrail (34 days, 95% CI 10-58, p = 0.005). CONCLUSIONS: Frailty is strongly and independently associated with 1-year mortality. The combined use of frailty and comorbidity may constitute an important risk prediction concept in regard to cardiovascular patients with complex needs.
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| 21. |
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| 22. |
- Eriksson, Mikael, et al.
(författare)
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The MAX IV Facility
- 2013
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Ingår i: 11th International Conference on Synchrotron Radiation Instrumentation (SRI 2012). - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 425
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Konferensbidrag (refereegranskat)abstract
- The MAX IV synchrotron radiation facility is currently being constructed in Lund, Sweden. The accelerator park consists of a 3 GeV linac injector and 2 storage rings operated at 1.5 and 3 GeV respectively. The linac injector will also be used for the generation of short Xray pulses. Close to 30 straight sections will be available for IDs at the rings. The three machines mentioned above are described below with some emphasis on the effort to create a very small emittance in the 3 GeV ring. Some unconventional technical solutions imposed by the emittance minimisation are discussed.
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| 23. |
- Eriksson, Mikael, et al.
(författare)
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The MAX IV Synchrotron Light Source
- 2011
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Ingår i: [Host publication title missing]. - 9789290833666 ; , s. 3026-3028
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Konferensbidrag (refereegranskat)abstract
- The MAX IV synchrotron radiation facility is currently being constructed in Lund, Sweden. It consists of a 3 GeV linac injector and 2 storage rings operated at 1.5 and 3 GeV respectively. The linac injector will also be used for the generation of short X-ray pulses. The three machines mentioned above are described with some emphasis on the effort to create a very small emittance in the 3 GeV ring. Some unconventional technical solutions will also be presented.
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| 24. |
- Fehr, Manuela A., et al.
(författare)
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Iron enrichments and Fe isotopic compositions of surface sediments from the Gotland Deep, Baltic Sea
- 2010
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Ingår i: Chemical Geology. - : Elsevier BV. - 0009-2541 .- 1872-6836. ; 277:3-4, s. 310-322
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Tidskriftsartikel (refereegranskat)abstract
- Recent sediments from the Gotland Deep display enrichments in reactive Fe, associated with elevated Fe/Al ratios and light Fe isotopic signatures of the bulk sediments that are indicative of euxinic (anoxic and sulfidic) conditions. These enrichments can be explained by the Fe shuttle model where benthic Fe is transported from the shelf to the euxinic basin and transferred to the sediments by pyrite precipitation in the sulfidic water. The data provide evidence that the Fe shuttle at present results in accumulations of Fe that are larger compared to Fe enrichments during the Litorina Sea stage in the Gotland Deep probably caused by an increase of the benthic Fe flux from the shelf to the basin. The derived Fe enrichments are also larger compared to those in recent Black Sea sediments, which likely reflects the larger shelf to basin ratio of the Gotland Deep compare to the Black Sea. The Fe isotope data show no correlation with the organic C content of the samples indicating that the negative Fe isotope signatures are not associated with organic materials, as was suggested as an alternative explanation for the origin of the isotopically light Fe in sediments from the Litorina Sea stage. Conversely, pyrites carry the negative Fe isotopic signature of the sediments, which supports the Fe shuttle model. Variations in the abundance and Fe isotopic signature of reactive Fe and pyrite with depth suggest that syngenetically formed pyrite in the sulfidic water column has a less negative Fe isotopic composition compared to diagenetically produced pyrite.
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| 25. |
- Forsberg, Anton, et al.
(författare)
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Low background and high contrast PET imaging of amyloid-β with [11C]AZD2995 and [11C]AZD2184 in Alzheimer's disease patients
- 2013
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer-Verlag New York. - 1619-7070 .- 1619-7089. ; 40:4, s. 580-593
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The aim of this study was to evaluate AZD2995 side by side with AZD2184 as novel PET radioligands for imaging of amyloid-β in Alzheimer's disease (AD).METHODS: In vitro binding of tritium-labelled AZD2995 and AZD2184 was studied and compared with that of the established amyloid-β PET radioligand PIB. Subsequently, a first-in-human in vivo PET study was performed using [(11)C]AZD2995 and [(11)C]AZD2184 in three healthy control subjects and seven AD patients.RESULTS: AZD2995, AZD2184 and PIB were found to share the same binding site to amyloid-β. [(3)H]AZD2995 had the highest signal-to-background ratio in brain tissue from patients with AD as well as in transgenic mice. However, [(11)C]AZD2184 had superior imaging properties in PET, as shown by larger effect sizes comparing binding potential values in cortical regions of AD patients and healthy controls. Nevertheless, probably due to a lower amount of nonspecific binding, the group separation of the distribution volume ratio values of [(11)C]AZD2995 was greater in areas with lower amyloid-β load, e.g. the hippocampus.CONCLUSION: Both AZD2995 and AZD2184 detect amyloid-β with high affinity and specificity and also display a lower degree of nonspecific binding than that reported for PIB. Overall [(11)C]AZD2184 seems to be an amyloid-β radioligand with higher uptake and better group separation when compared to [(11)C]AZD2995. However, the very low nonspecific binding of [(11)C]AZD2995 makes this radioligand potentially interesting as a tool to study minute levels of amyloid-β. This sensitivity may be important in investigating, for example, early prodromal stages of AD or in the longitudinal study of a disease modifying therapy.
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| 26. |
- Gustafsson Coppel, Ludovic, 1975-, et al.
(författare)
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Fluorescence model for multi-layer papers using conventional spectrophotometers
- 2012
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:2, s. 418-425
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Tidskriftsartikel (refereegranskat)abstract
- We present an extension of a Kubelka- Munk based fluorescence model in which we introduce an apparent scattering (S UV) and absorption (K UV) coefficient for all wavelengths below 400 nm. We describe a method for modelling the total radiance factor of multi-layer papers and for estimating the optical parameters (S, K and Q) of each layer. Assuming that the fluorescent whitening agent only absorbs below 400 nm, we are able to determine S UV, K UV and the apparent quantum efficiency, Q(UV,λ) for 400 nm<λ<700 nm, from spectral radiance measurements in the visual part of the electromagnetic spectrum. We test the proposed method on different layered constructions made of three individual pilot paper layers. The proposed method allows the papermaker to determine the illumination independent fluorescence characteristics of single- and multilayer paper layers using a conventional singlemonochromator spectrophotometer operating in the visible part of the electromagnetic spectrum, and also to predict the radiance factor of fluorescing layered papers.
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| 27. |
- Hallén, Per, 1969, et al.
(författare)
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Gateways and shipping during the early modern times - The Gothenburg example 1720-1804
- 2012
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Ingår i: Paper for the Ninth European Social Science History Conference (ESSHC): session: Commodity Chains in the First Period of Globalization in Glasgow 11–14 April, 2012..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the 2010 Journal of Transport Geography Notteboom presented how the structure of Europe's container ports has been during 1985-2005. An economic historian who has studied trade during the early modern times immediately recognises the overview. There are striking resemblances between the gateways and multi-gateways port regions that Notteboom works with and with trade during the early modern times. The trade routes and transport systems built up during the age of sail ships have, in large part, the same importance today. This clearly shows that research in early modern trade and shipping has an important role to play when it comes to understanding modern infrastructure. In our paper, we will work with the shipping and trade through the gateway city of Gothenburg during chosen years between 1720 and 1804. The city's location between the North Sea and the Baltic Sea places it in the middle of one of the central regions in the world's economic development during the first period of globalisation. It was in this region that the superpowers of the time got much of the raw materials they needed. To try to understand the shape of shipping and trade in this region is therefore vital to understanding global developments. The source material is made up by custom records from Gothenburg harbour. These will be used to track ship movements to and from Gothenburg to determine the city's place in a larger system of gateways, primarily when it comes to the textiles and coal groups of goods, as well as products related to the substantial herring fishing industry. The theoretical starting point for the study is the extensive structure of theories that have been developed around gateways. Different opportunities to use the custom records in an analysis of shipping structure will be discussed. Which part of the information in the source material is suitable to use (goods, skipper, destinations)? How can one, in the best possible way, make the results comparable to other studies? This is a few of the questions that will be discussed in our methods section. The main point of this paper will be the analysis of the gateway system as seen from the Gothenburg horizon.
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| 28. |
- Jesson, Gerald, et al.
(författare)
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Carbon Dioxide-Mediated Generation of Hybrid Nanoparticles for Improved Bioavailability of Protein Kinase Inhibitors
- 2014
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Ingår i: Pharmaceutical research. - : Springer Science and Business Media LLC. - 0724-8741 .- 1573-904X. ; 31:3, s. 694-705
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Tidskriftsartikel (refereegranskat)abstract
- A versatile methodology is demonstrated for improving dissolution kinetics, gastrointestinal (GI) absorption, and bioavailability of protein kinase inhibitors (PKIs). The approach is based on nanoparticle precipitation by sub- or supercritical CO2 together with a matrix-forming polymer, incorporating surfactants either during or after nanoparticle formation. Notably, striking synergistic effects between hybrid PKI/polymer nanoparticles and surfactant added after particle formation is investigated. The hybrid nanoparticles, consisting of amorphous PKI embedded in a polymer matrix (also after 12 months), display dramatically increased release rate of nilotinib in both simulated gastric fluid and simulated intestinal fluid, particularly when surfactants are present on the hybrid nanoparticle surface. Similar results indicated flexibility of the approach regarding polymer identity, drug load, and choice of surfactant. The translation of the increased dissolution rate found in vitro into improved GI absorption and bioavalilability in vivo was demonstrated for male beagle dogs, where a 730% increase in the AUC(0-24h) was observed compared to the benchmark formulation. Finally, the generality of the formulation approach taken was demonstrated for a range of PKIs. Hybrid nanoparticles combined with surfactant represent a promising approach for improving PKI dissolution rate, providing increased GI absorption and bioavailability following oral administration.
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| 29. |
- Johansson, Niklas, et al.
(författare)
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Influence of finite-sized detection solid angle on bidirectional reflectance distribution function measurements
- 2014
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Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 53:6, s. 1212-1220
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with limitations and often overlooked sources of error introduced in compact double-beam goniophotometers. It is shown that relative errors in measured radiance factor, comparable to the total measurement uncertainty, can be introduced if recommended corrections are not carried out. Two different error sources are investigated, both related to the size of the detection solid angle. The first is a geometrical error that occurs when the size of the illuminated area and detector aperture are comparable to the distance between them. The second is a convolution error due to variations in radiant flux over the detector aperture, which is quantified by simulating the full 3D bidirectional reflectance distribution function (BRDF) of a set of samples with different degrees of anisotropic reflectance. The evaluation is performed for a compact double-beam goniophotometer using different detection solid angles, and it is shown that both error sources introduce relative errors of 1%–3%, depending on viewing angle and optical properties of the sample. Commercially available compact goniophotometers, capable of absolute measurements, are becoming more and more common, and the findings in this paper are therefore important for anyone using or planning to use this type of instrument.
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| 30. |
- Johansson, Niklas, 1973-, et al.
(författare)
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Separation of surface and bulk reflectance by absorption of bulk scattered light
- 2013
-
Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 52:19, s. 4749-4754
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Tidskriftsartikel (refereegranskat)abstract
- A method is proposed for separating light reflected from turbid media with a rough surface into a bulkand a surface component. Dye is added to the sample, thereby increasing absorption and canceling bulkscattering. The remaining reflected light is surface reflectance, which can be subtracted from the totalreflectance of an undyed sample to obtain the bulk component. The method is applied to paper wherethe addition of dye is accomplished by inkjet printing. The results show that the bulk scattered light isefficiently canceled, and that both the spectrally neutral surface reflectance and the surface topographyof the undyed paper is maintained. The proposed method is particularly suitable for characterization ofdielectric, highly randomized materials with significant bulk reflectance and rough surfaces, which aredifficult to analyze with existing methods. A reliable separation method opens up for new ways of analyzing,e.g., biological tissues and optical coatings, and is also a valuable tool in the development of morecomprehensive reflectance models.
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| 31. |
- Korsgren, Magnus, et al.
(författare)
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Inhalation of LPS induces inflammatory airway responses mimicking characteristics of chronic obstructive pulmonary disease.
- 2012
-
Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 32:1, s. 71-79
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Inhalation of lipopolysaccharide (LPS) produces both systemic and pulmonary inflammatory responses. The aim of this study was to further characterize the response to LPS in order to develop a human model suitable for early testing of drug candidates developed for the treatment for chronic obstructive pulmonary disease (COPD). Materials: Blood and induced sputum were obtained 4, 24 and 48 h following inhalation of saline and LPS (5 and 50 μg). Blood was analysed for C-reactive protein (CRP), α(1) -antitrypsin and neutrophils/leucocytes, and sputum was analysed for biomarkers of neutrophil inflammation and remodelling activities, i.e. neutrophil elastase (NE) protein/activity and α(1) -antitrypsin. Levels of tumour necrosis factor-α (TNFα) were measured in both blood and sputum. Urine was collected 0-24 and 24-48 h postchallenge, and desmosine, a biomarker of elastin degradation, was measured. Results: Lipopolysaccharide inhalation induced dose-dependent flu-like symptoms and increases in plasma CRP and α(1) -antitrypsin as well as increases in blood neutrophil/leucocyte numbers. Furthermore, LPS produced increases in sputum TNFα and sputum NE activity. Urine levels of desmosine were unaffected by the LPS challenge. All subjects recovered 48 h postchallenge, and indices of inflammatory activity were significantly lower at this observation point cf 24 h postchallenge. Conclusion: Inhalation of LPS in healthy volunteers can be used as a safe and stable model of neutrophil inflammation. Blood/plasma and sputum indices can be employed to monitor the response to LPS. We suggest that this model may be used for initial human studies of novel COPD-active drugs.
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| 32. |
- Lauridsen, Jonas, et al.
(författare)
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Microstructural and Chemical Analysis of AgI Coatings Used as a Solid Lubricant in Electrical Sliding Contacts
- 2012
-
Ingår i: Tribology letters. - : Springer Verlag (Germany). - 1023-8883 .- 1573-2711. ; 46:2, s. 187-193
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Tidskriftsartikel (refereegranskat)abstract
- AgI coatings have been deposited by electroplating on Ag-plated Cu coupons. Electron microscopy shows that the coatings consist of weakly agglomerated AgI grains. X-ray diffraction, differential scanning calorimetry, thermogravimetry, and mass spectrometry show that the AgI exhibits a reversible transformation from hexagonal to cubic phase at 150 A degrees C. AgI starts to decompose at 150 A degrees C with an accelerating rate up to the AgI melting temperature (555 A degrees C), where a complex-bonded hydroxide evaporates. Ag pin-on-disk testing shows that the iodine addition to Ag decreases the friction coefficient from 1.2 to similar to 0.4. The contact resistance between AgI and Ag becomes less than 100 mu I (c) after similar to 500 operations as the AgI deagglomerates, and Ag is exposed on the surface and remains low during at least 10,000 reciprocating operations. This makes AgI suitable as a solid lubricant in electrical contacts.
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| 33. |
- Lequien, Guillaume, et al.
(författare)
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A Correlation Analysis of the Roles of Soot Formation and Oxidation in a Heavy-Duty Diesel Engine
- 2013
-
Ingår i: SAE Technical Paper Series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
-
Konferensbidrag (refereegranskat)abstract
- Emissions and in-cylinder pressure traces are used to compare the relative importance of soot formation and soot oxidation in a heavy-duty diesel engine. The equivalence ratio at the lift-off length is estimated with an empirical correlation and an idealized model of diesel spray. No correlation is found between the equivalence ratio at lift-off and the soot emissions. This confirms that trends in soot emissions cannot be directly understood by the soot formation process. The coupling between soot emission levels and late heat release after end of injection is also studied. A regression model describing soot emissions as function of global engine parameters influencing soot oxidation is proposed. Overall, the results of this analysis indicate that soot emissions can be understood in terms of the efficiency of the oxidation process.
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| 34. |
- Lindqvist, Camilla, 1985, et al.
(författare)
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Fullerene Nucleating Agents: A Route Towards Thermally Stable Photovoltaic Blends
- 2014
-
Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6840 .- 1614-6832. ; 4:9, s. 1301437-
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Tidskriftsartikel (refereegranskat)abstract
- The bulk-heterojunction nanostructure of non-crystalline polymer: fullerene blends has the tendency to rapidly coarsen when heated above its glass transition temperature, which represents an important degradation mechanism. We demonstrate that fullerene nucleating agents can be used to thermally arrest the nanostructure of photovoltaic blends that comprise a non-crystalline thiophene-quinoxaline copolymer and the widely used fullerene derivative [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM). To this end, C-60 fullerene is employed to efficiently nucleate PCBM crystallization. Sub-micrometer-sized fullerene crystals are formed when as little as 2 wt% C-60 with respect to PCBM is added to the blend. These reach an average size of only 200 nanometers upon introduction of more than 8 wt% C-60. Solar cells based on C-60-nucleated blends indicate significantly improved thermal stability of the bulk-heterojunction nanostructure even after annealing at an elevated temperature of 130 degrees C, which lies above the glass transition temperature of the blend. Moreover, we find that various other compounds, including C-70 fullerene, single-walled carbon nanotubes, and sodium benzoate, as well as a number of commercial nucleating agents-commonly used to clarify isotactic polypropylene-permit to control crystallization of the fullerene phase.
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| 35. |
- Neuman, Magnus, et al.
(författare)
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Angular Variations of Color in Turbid Media – the Influence of Bulk Scattering on Goniochromism in Paper
- 2010
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Ingår i: 5th European Conference on Colour in Graphics, Imaging, and Vision and 12th International Symposium on Multispectral Colour Science 2010, CGIV 2010/MCS'10. - 9781617388897 ; , s. 407-413
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Konferensbidrag (refereegranskat)abstract
- The angular variations of color of a set of paper samples are experimentally assessed using goniophotometric measurements. The corresponding simulations are done using a radiative transfer based simulation tool, thus considering only the contribution of bulk scattering to the reflectance. It is seen that measurements and simulations agree and display the same characteristics, with the lightness increasing and the chroma decreasing as the observation polar angle increases. The decrease in chroma is larger the more dye the paper contains. Based on previous results about anisotropic reflectance from turbid media these findings are explained. The relative reflectance in large polar angles of wavelengths with strong absorption is higher than that of wavelengths with low absorption. This leads to a loss of chroma and color information in these angles. The increase in lightness is a result of the anisotropy affecting all wavelengths equally, which is the case for transmitting media and obliquely incident illumination. The only case with no color variations of this kind is when a nonabsorbing, non-transmitting medium is illuminated diffusely. The measured and simulated color differences are clearly large, and it is an open issue how angle resolved color should be handled in standard color calculations.
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| 36. |
- Pasternak, Björn, et al.
(författare)
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Elevated intraperitoneal matrix metalloproteinases-8 and -9 in patients who develop anastomotic leakage after rectal cancer surgery: a pilot study
- 2010
-
Ingår i: Colorectal Disease. - Chichester, West Sussex, United Kingdom : Wiley-Blackwell. - 1462-8910 .- 1463-1318. ; 12:7, s. e93-e98
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Tidskriftsartikel (refereegranskat)abstract
- Objective Experimental studies suggest that matrix metalloproteinase (MMP) enzymes mediate the early tissue breakdown that leads to a decrease in intestinal anastomotic strength. Patients with upregulation of MMPs in intestinal biopsies have an increased rate of anastomotic leakage. We measured MMPs and their inhibitors [tissue inhibitors of metalloproteinases (TIMPs)] in postoperative intraperitoneal fluid after rectal cancer surgery, and hypothesized that they would be elevated in patients who later would develop anastomotic leakage.Method Twenty-nine patients with rectal carcinoma underwent low anterior resection of the rectum for cancer. Intraperitoneal fluid was collected via a pelvic drain at a median of 4 h postoperatively. MMP-1, -2, -3, -7, -8, -9 and -13 were determined using particle-based multiplex flow-cytometry. TIMP-1 and -2 were measured by enzyme-linked immunosorbent assays. MMP-9 was considered the main outcome variable.Results Ten patients developed anastomotic leakage. These patients had increased intraperitoneal MMP-9 [median difference (m.d.) 29%; P = 0.03] and MMP-8 (m.d. 58%; P = 0.02), compared with patients who did not develop leakage. There were no differences between the groups for other MMPs and TIMPs.Conclusion Matrix metalloproteinase-8 and -9 appear to have an important role in the development of anastomotic leakage and may be promising pharmacological targets to protect anastomotic integrity. We suggest further investigation of MMPs as markers for anastomotic leakage.
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| 37. |
- Sandström, Alfred, et al.
(författare)
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Population collapses in introduced non-indigenous crayfish
- 2014
-
Ingår i: Biological Invasions. - : Springer Science and Business Media LLC. - 1387-3547 .- 1573-1464. ; 16:9, s. 1961-1977
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Tidskriftsartikel (refereegranskat)abstract
- Invasive species often have instable population dynamics and are known to collapse or oscillate heavily after passing through the initial lag/growth phases. Long-term data-series documenting these fluctuations are however rare. We use long-term (starting in the early 1960s), semi-quantitative data on the invasive signal crayfish (Pacifastacus leniusculus), capturing its population development after introduction in 44 Swedish lakes. In total 18 (41 %) of these populations had experienced a collapse. A stepwise discriminant function analysis including 20 different ecological or physicochemical characteristics identified three variables explaining collapses in the following order: stocking year, population age and mean air temperature. Populations stocked in the 1980s were more likely to collapse than populations stocked in the 1970s. Lakes with collapses were located in areas with 0.4 A degrees C higher yearly mean air temperatures than the still viable populations. Collapses also depended on the time phase of the population and started to occur 12 years after stocking and were most frequent in the interval 16-20 years after stocking and after 11-15 years duration of the established phase with harvestable densities. An analysis of prevalence and pathogen load of Aphanomyces astaci was conducted in eight of the studied populations. A. astaci was present in all populations but neither the level of prevalence nor the pathogen load in infested specimens differed significantly between lakes with collapses and lakes without. Our results highlight the potential sensitivity and instability of introduced crayfish. The importance of density-dependence and temperature suggest that both climate variability and/or fisheries can influence these processes.
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| 38. |
- Sun, Xiaole, 1983-, et al.
(författare)
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Climate Dependent Diatom Production is Preserved in Biogenic Si Isotope Signatures
- 2011
-
Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 8:11, s. 3491-3499
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to reconstruct diatom production in the subarctic northern tip of the Baltic Sea, Bothnian Bay, based on down-core analysis of Si isotopes in biogenic silica (BSi). Dating of the sediment showed that the samples covered the period 1820 to 2000. The sediment core record can be divided into two periods, an unperturbed period from 1820 to 1950 and a second period affected by human activities (from 1950 to 2000). This has been observed elsewhere in the Baltic Sea. The shift in the sediment core record after 1950 is likely caused by large scale damming of rivers. Diatom production was inferred from the Si isotope composition which ranged between δ30Si −0.18‰ and +0.58‰ in BSi, and assuming fractionation patterns due to the Raleigh distillation, the production was shown to be correlated with air and water temperature, which in turn were correlated with the mixed layer (ML) depth. The sedimentary record showed that the deeper ML depth observed in colder years resulted in less production of diatoms. Pelagic investigations in the 1990's have clearly shown that diatom production in the Baltic Sea is controlled by the ML depth. Especially after cold winters and deep water mixing, diatom production was limited and dissolved silicate (DSi) concentrations were not depleted in the water column after the spring bloom. Our method corroborates these findings and offers a new method to estimate diatom production over much longer periods of time in diatom dominated aquatic systems, i.e. a large part of the world's ocean and coastal seas.
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| 39. |
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| 40. |
- Sun, Xiaole, 1983-
(författare)
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Isotope-based reconstruction of the biogeochemical Si cycle : Implications for climate change and human perturbation
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The global silicon (Si) cycle is of fundamental importance for the global carbon cycle. Diatom growth in the oceans is a major sequestration pathway for carbon on a global scale (often referred to as the biological pump). Patterns of diatoms preserved in marine sediment records can reveal both natural and anthropogenic driven environmental change, which can be used to understand silicon dynamics and climate change. Si isotopes have been shown to have great potential in order to understand the Si cycle by revealing both past and present patterns of dissolved Si (DSi) utilization, primarily when diatoms form their siliceous frustules (noted as biogenic silica, BSi). However, studies using Si isotopes are still scarce and only a few studies exist where stable Si isotopes are used to investigate the biogeochemical Si cycle in aquatic systems. Therefore, this thesis focuses on developing analytical methods for studying BSi and DSi and also provides tools to understand the observed Si isotope distribution, which may help to understand impacts of climate change and human perturbations on marine ecosystems. The Baltic Sea, one of the biggest estuarine systems in the world, was chosen as the study site. BSi samples from a sediment core in Bothnian Bay, the most northern tip of the Baltic Sea, and diatom samples from the Oder River, draining into the southern Baltic Sea were measured and reported in Paper II and III, after establishing a method for Si isotope measurements (Paper I). Si isotope fractionation during diatom production and dissolution was also investigated in a laboratory-controlled experiment (Paper IV) to validate the observations from the field. The major result is that Si isotope signatures in BSi can be used as an historical archive for diatom growth and also related to changes in climate variables. There is isotopic evidence that the Si cycle has been significantly altered in the Baltic Sea catchment by human activities.
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| 41. |
- Sun, Xiaole, et al.
(författare)
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Silicon isotope enrichment in diatoms during nutrient-limited blooms in a eutrophied river system
- 2013
-
Ingår i: Journal of Geochemical Exploration. - : Elsevier BV. - 0375-6742 .- 1879-1689. ; 132, s. 173-180
-
Tidskriftsartikel (refereegranskat)abstract
- We examined the Si isotope fractionation by following a massive nutrient limited diatom bloom in a eutrophied natural system. The Oder River, which is a eutrophied river draining the western half of Poland and entering the southern Baltic Sea, exhibits diatom blooms that cause extreme Si isotope fractionation. The rapid nutrient depletion and fast BSi increase observed during the spring bloom suggest a closed system Rayleigh behavior for DSi and BSi in the river at certain time scales. A Si isotope fractionation factor ((30)epsilon(Dsi-Bsi)) of -1.6 +/- 0.31%. (2 sigma) is found based on observations between April and June, 2004. A very high delta Si-30 value of up to +3.05 parts per thousand. is measured in BSi derived from diatoms. This is about 2 times higher than previously recorded delta Si-30 in freshwater diatoms. The Rayleigh model used to predict the delta Si-30 values of DSi suggests that the initial value before the start of the diatom bloom is close to +2 parts per thousand, which is relatively higher than the previously reported values in other river water. This indicates that there is a biological control of the Si isotope compositions entering the river, probably caused by Si isotope fractionation during uptake of Si in phytoliths. Clearly, eutrophied rivers with enhanced diatom blooms deliver Si-30-enriched DSi and BSi to the coastal ocean, which can be used to trace the biogeochemistry of DSi/BSi in estuaries.
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| 42. |
- Tzamalis, G., et al.
(författare)
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Fluorescence light emission at 1 eV from a conjugated polymer
- 2010
-
Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 489:1-3, s. 92-95
-
Tidskriftsartikel (refereegranskat)abstract
- While polymer light-emitting diodes are currently finding commercial applications in displays and lighting, the development of low bandgap polymers emitting in the infrared has received much less attention in spite of potential applications for instance in the field of communication technologies. We report here a light emission at 1 eV from a low bandgap polymer made of an alternation of dialkoxy-phenylene units and a low bandgap monomer composed of an electron accepting 2-thia-1,3,5,8-tetraaza-cyclopenta[b]naphthalene group fenced with electron donating thiophene units. The electronic structure of the polymer chains has been characterized at a quantum-chemical level to shed light into the experimental results. (C) 2010 Published by Elsevier B.V.
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| 43. |
- Wang-Hansen, Carolin, 1982, et al.
(författare)
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Experimental Method for Kinetic Studies of Gas-Solid Reactions: Oxidation of Carbonaceous Matter
- 2011
-
Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:32, s. 16098-16108
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Tidskriftsartikel (refereegranskat)abstract
- A methodology comprising careful consideration of sample preparation, reactor design, experimental procedures, and data evaluation routines for precise analysis of the kinetics of gas␣solid reactions, specifically the oxidation of carbonaceous materials, has been developed and validated. The wellcontrolled solvent-free deposition of the carbonaceous material onto cordierite monolith substrates ensures experimental stud- ies in the absence of diffusion limitations, temperature gradients, and hot zones. These critical aspects are supported also by theoretical considerations. Temperature-programmed oxida- tion and isothermal oxygen step-response experiments in a continuous gas-flow reactor using a homogeneous synthetic carbon- black material demonstrate excellent reproducibility, and the conversion profiles agree well with previously reported data. An independent set of global kinetic parameters was estimated for each 5% subconversion interval using linear regression such that the conversion dependence of each parameter could be analyzed separately and compared to previously published data. The results show that the evolution of reactive carbons cannot be described with a single global reaction order. This is supported by intermittent ex situ measurements of the specific surface area of the carbon-black material during the course of isothermal oxidation, which reveals a developing microporous structure at high conversions. Physically the changes in carbon reaction order are interpreted as changes in fraction of accessible reactive carbon atoms during progressing oxidation. Moreover, at high conversions, the carbon reaction order approaches 0.7 implying not only that the evolution of the concentration of reactive carbon atoms is proportional to the external surface area of shrinking spheres but also that these spheres have approximately the same size.
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