| 1. |
- Rosén, Tomas, 1985-, et al.
(författare)
-
Cross-Sections of Nanocellulose from Wood Analyzed by Quantized Polydispersity of Elementary Microfibrils
- 2020
-
Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 14:12, s. 16743-16754
-
Tidskriftsartikel (refereegranskat)abstract
- Bio-based nanocellulose has been shown to possess impressive mechanical properties and simplicity for chemical modifications. The chemical properties are largely influenced by the surface area and functionality of the nanoscale materials. However, finding the typical cross-sections of nanocellulose, such as cellulose nanofibers (CNFs), has been a long-standing puzzle, where subtle changes in extraction methods seem to yield different shapes and dimensions. Here, we extracted CNFs from wood with two different oxidation methods and variations in degree of oxidation and high-pressure homogenization. The cross-sections of CNFs were characterized by small-angle X-ray scattering and wide-angle X-ray diffraction in dispersed and freeze-dried states, respectively, where the results were analyzed by assuming that the cross-sectional distribution was quantized with an 18-chain elementary microfibril, the building block of the cell wall. We find that the results agree well with a pseudosquare unit having a size of about 2.4 nm regardless of sample, while the aggregate level strongly depends on the extraction conditions. Furthermore, we find that aggregates have a preferred cohesion of phase boundaries parallel to the (110)-plane of the cellulose fibril, leading to a ribbon shape on average.
|
|
| 2. |
- Abarenkov, Kessy, et al.
(författare)
-
The UNITE database for molecular identification and taxonomic communication of fungi and other eukaryotes: sequences, taxa and classifications reconsidered
- 2024
-
Ingår i: Nucleic Acids Research. - 0305-1048 .- 1362-4962. ; 52:D1, s. D791-D797
-
Tidskriftsartikel (refereegranskat)abstract
- UNITE (https://unite.ut.ee) is a web-based database and sequence management environment for molecular identification of eukaryotes. It targets the nuclear ribosomal internal transcribed spacer (ITS) region and offers nearly 10 million such sequences for reference. These are clustered into similar to 2.4M species hypotheses (SHs), each assigned a unique digital object identifier (DOI) to promote unambiguous referencing across studies. UNITE users have contributed over 600 000 third-party sequence annotations, which are shared with a range of databases and other community resources. Recent improvements facilitate the detection of cross-kingdom biological associations and the integration of undescribed groups of organisms into everyday biological pursuits. Serving as a digital twin for eukaryotic biodiversity and communities worldwide, the latest release of UNITE offers improved avenues for biodiversity discovery, precise taxonomic communication and integration of biological knowledge across platforms. Graphical Abstract
|
|
| 3. |
- Abdalla, H., et al.
(författare)
-
Gamma-ray blazar spectra with HESS II mono analysis : The case of PKS2155-304 and PG1553+113
- 2017
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 600
-
Tidskriftsartikel (refereegranskat)abstract
- Context. The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument's energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift >= 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553 + 113 (0.43 < z < 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims. The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155-304 and PG 1553 + 113 near their SED peaks at energies approximate to 100 GeV. Methods. Multiple observational campaigns of PKS 2155 304 and PG 1553 + 113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1-5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results. Using the data from CT5, the energy spectra of PKS 2155 304 and PG 1553 + 113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155 304, which transits near zenith, and 110 GeV for the more northern PG 1553 + 113. The measured spectra, well fitted in both cases by a log-parabola spectral model ( with a 5.0 similar to statistical preference for non-zero curvature for PKS 2155 304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E approximate to 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155 304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties.
|
|
| 4. |
-
Aktörer och marknader i omvandling : studier i företagandets historia tillägnade Kersti Ullenhag
- 2011
-
Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- This book is a Festschrift to professor emerita Kersti Ullenhag in honour of her 75th birthday. Kersti Ullenhag has been a teacher and researcher in economic history at Uppsala University since the mid 1960’s. Her research has focused on different aspects of business history, often combining micro-oriented empirical case studies with Schumpeterian theories on entrepreneurship. In 19 chapters this book deals with research topics such as the roots of business history,political economy, business and entrepreneurship, the development of financial markets and gender perspectives in business and society.
|
|
| 5. |
- Bergström, Göran, 1977-
(författare)
-
Från svensk malmexport till utländsk etablering : Grängesbergsbolagets internationalisering 1953-1980
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of this thesis is to analyze the internationalisation of the Grängesberg Company from 1953 to 1980. The strategies that the company used and the knowledge it gained by participating in international mining projects are studied. The first and largest mining activity abroad was the Lamco project in Liberia. By transferring the company’s competence and knowledge of mining activities to Liberia, the Grängesberg Company used an international strategy of horizontal integration. The company’s contacts were of importance to start the production in 1963. The main ambition was thereafter to negotiate new long-term contracts in order to create stability for the project in the 1960s and the 1970s. Through its involvement in the Lamco project, the Grängesberg Company also acquired shares in a Belgian steel company and became half-owner with the Liberian state in a foreign shipping company. The experience and knowledge that the company gained in the Lamco project was used to increase its internationalisation in the 1970s. Appointing a Mineral Project Group, it investigated existing mineral projects abroad and formulated new internationalisation strategies such as vertical integration and diversification. The main motive for the further expansion abroad in the mining area was a need for resources for its domestic production. The most important outcome was the acquisition of a Canadian copper company, and the company integrated backwards to gain access to copper. The Grängesberg Company also used its competence by doing prospecting work in New Caledonia, Peru and Canada and consultant work in mining projects in Iran and Saudi Arabia in the 1970s. The study has shown that further international expansion became limited because of the downturn of the international economy in the 1970s, but also because of the company’s cautious attitude towards the political risks that were associated with international mining projects.
|
|
| 6. |
- Björn, Erik, et al.
(författare)
-
Recent Advances in Mercury Speciation Analysis with Focus on Spectrometric Methods and Enriched Stable Isotope Applications
- 2007
-
Ingår i: Ambio. - 0044-7447 .- 1654-7209. ; 36:6, s. 443–51-
-
Tidskriftsartikel (refereegranskat)abstract
- This paper discusses some recent advances in spectrometric methods and approaches for mercury speciation analysis of environmental samples with focus on isotope dilution techniques for determination of mercury species' concentrations in gaseous samples and reaction rates in soils and sediments. Such analytical data is important inter alia in fundamental research on mercury biogeochemistry and for risk assessments of mercury-contaminated soils and sediments and for designing effective remedial actions. The paper describes how the use of enriched stable isotope tracers in mercury speciation analysis can improve the traceability and accuracy of results, facilitate rational method developments, and be useful for studying biogeochemical processes, i.e. rate of reactions and fluxes, of mercury species. In particular the possibilities to study and correct for unwanted species transformation reactions during sample treatment and to study “natural” transformations of species in environmental samples, or micro- and mesocosm ecosystems, during incubations are highlighted. Important considerations to generate relevant data in isotope tracer experiments as well as reliability and quality assurance of mercury speciation analysis in general are also discussed.
|
|
| 7. |
- Boud, David, et al.
(författare)
-
Creating a world class program : Reciprocity and constraints in global study.
- 2006
-
Ingår i: International Journal of Lifelong Education. - : Informa UK Limited. - 0260-1370 .- 1464-519X. ; 25:6, s. 609-622
-
Tidskriftsartikel (refereegranskat)abstract
- The article reflects on the construction of a common Master's programme across four universities located on four continents, in order to explore the role of networks in international educational collaboration. The study draws on the documented processes of the principal members of the programme team. It is presented as a case study of the development of the programme that uses ideas drawn from actor-network theory to draw attention to the conjunction of human and non-human actors that shaped the resulting web-based courses. Constraints arising from major institutional and systemic obstacles were addressed through the effects of the actor-network. The reciprocity of action and de-centring of individual activity made possible through the collaboration enabled the human actors to sustain a level of innovation within their own institutions that would not have been possible through them acting alone.
|
|
| 8. |
- Boud, David, et al.
(författare)
-
Making sense of new forms of practice : multiple perspectives in researching an intercultural programme across continents.
- 2006
-
Ingår i: Standing Conference on University Teaching and Research in the Education of Adults,2006.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The focus of the symposium is on researching a programme with multiple sites of practice (in four conutries on four continents), learners distributed across the world and an emphasis on a pedagogy that embeds intercultural understanding. Studies from different perspectives are used to explore research issues in intercultural courses.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
- Carlström, Mattias, 1941-, et al.
(författare)
-
Dietary nitrate attenuates oxidative stress, prevents cardiac and renal injuries, and reduces blood pressure in salt-induced hypertension
- 2011
-
Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 89:3, s. 574-585
-
Tidskriftsartikel (refereegranskat)abstract
- Aims Reduced bioavailability of endogenous nitric oxide (NO) is a central pathophysiological event in hypertension and other cardiovascular diseases. Recently, it was demonstrated that inorganic nitrate from dietary sources is converted in vivo to form nitrite, NO, and other bioactive nitrogen oxides. We tested the hypothesis that dietary inorganic nitrate supplementation may have therapeutic effects in a model of renal and cardiovascular disease. Methods and results Sprague-Dawley rats subjected to unilateral nephrectomy and chronic high-salt diet from 3 weeks of age developed hypertension, cardiac hypertrophy and fibrosis, proteinuria, and histological as well as biochemical signs of renal damage and oxidative stress. Simultaneous nitrate treatment (0.1 or 1 mmol nitrate kg(-1) day(-1)), with the lower dose resembling the nitrate content of a diet rich in vegetables, attenuated hypertension dose-dependently with no signs of tolerance. Nitrate treatment almost completely prevented proteinuria and histological signs of renal injury, and the cardiac hypertrophy and fibrosis were attenuated. Mechanistically, dietary nitrate restored the tissue levels of bioactive nitrogen oxides and reduced the levels of oxidative stress markers in plasma (malondialdehyde) and urine (Class VI F2-isoprostanes and 8-hydroxy-2-deoxyguanosine). In addition, the increased circulating and urinary levels of dimethylarginines (ADMA and SDMA) in the hypertensive rats were normalized by nitrate supplementation. Conclusion Dietary inorganic nitrate is strongly protective in this model of renal and cardiovascular disease. Future studies will reveal if nitrate contributes to the well-known cardioprotective effects of a diet rich in vegetables.
|
|
| 12. |
- Carlström, Mattias, et al.
(författare)
-
Role of nitric oxide deficiency in the development of hypertension in hydronephrotic animals
- 2008
-
Ingår i: American Journal of Physiology - Renal Physiology. - : American Physiological Society. - 0363-6127 .- 1522-1466 .- 1931-857X. ; 294:2, s. 362-370
-
Tidskriftsartikel (refereegranskat)abstract
- Hydronephrotic animals develop renal injury and hypertension, which is associated with an abnormal tubuloglomerular feedback (TGF). The TGF sensitivity is coupled to nitric oxide (NO) in the macula densa. The involvement of reduced NO availability in the development of hypertension in hydronephrosis was investigated. Hydronephrosis was induced by ureteral obstruction in young rats. Blood pressure and renal excretion were measured in adulthood, under different sodium conditions, and before and after chronic administration of either N-G- nitro-L-arginine methyl ester (L-NAME) or L-arginine. Blood samples for ADMA, SDMA, and L-arginine analysis were taken and the renal tissue was used for histology and determination of NO synthase (NOS) proteins. TGF characteristics were determined by stop-flow pressure technique before and after administration of 7-nitroindazole (7-NI) or L-arginine. Hydronephrotic animals developed salt-sensitive hypertension, which was associated with pressure natriuresis and diuresis. The blood pressure response to L-NAME was attenuated and L-arginine supplementation decreased blood pressure in hydronephrotic animals, but not in the controls. Under control conditions, reactivity and sensitivity of the TGF response were greater in the hydronephrotic group. 7-NI administration increased TGF reactivity and sensitivity in control animals, whereas, in hydronephrotic animals, neuronal NOS (nNOS) inhibition had no effect. L-Arginine attenuated TGF response more in hydronephrotic kidneys than in controls. The hydronephrotic animals displayed various degrees of histopathological changes. ADMA and SDMA levels were higher and the renal expressions of nNOS and endothelial NOS proteins were lower in animals with hydronephrosis. Reduced NO availability in the diseased kidney in hydronephrosis, and subsequent resetting of the TGF mechanism, plays an important role in the development of hypertension.
|
|
| 13. |
- Cervin-Ellqvist, Maria, 1994, et al.
(författare)
-
Metacognitive illusion or self-regulated learning? Assessing engineering students’ learning strategies against the backdrop of recent advances in cognitive science
- 2021
-
Ingår i: Higher Education. - : Springer Science and Business Media LLC. - 1573-174X .- 0018-1560. ; 82:3, s. 477-498
-
Tidskriftsartikel (refereegranskat)abstract
- Knowing how students approach learning in higher education contexts is key to promote learning strategies that are effective in the long run. Previous research has concluded that students often use ineffective learning strategies but believe them to be effective—a phenomenon known as metacognitive illusion. In a bid to broaden the perspective on students’ use of learning strategies, this study draws on the notion of self-regulated learning as a theoretical lens. A questionnaire, comprising both open-ended and closed-ended questions, was developed to gather data from 416 engineering students. The questionnaire was geared towards (1) mapping what learning strategies students use in a real-world setting, in real courses, (2) probing their metacognitive awareness of the effectiveness of various learning strategies and (3) investigating why students choose certain learning strategies. We also compared which learning strategies the engineering students chose across programs and types of courses. The findings reveal a complex picture of why students sometimes use seemingly ineffective learning strategies, and we conclude that this is not always due to metacognitive illusion. It is instead often linked to attempts to regulate behaviour, motivation and/or learning context, sometimes in response to the context. This study adds to the current HE research investigating students’ abilities to reflect on, assess and take control of their learning in an effective way, confirming that students need explicit guidance.
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
- Coenye, Tom, et al.
(författare)
-
Advenella incenata gen. nov., sp nov., a novel member of the Alcaligenaceae, isolated from various clinical samples
- 2005
-
Ingår i: INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY. - : Microbiology Society. - 1466-5026 .- 1466-5034. ; 55, s. 251-256
-
Tidskriftsartikel (refereegranskat)abstract
- A polyphasic taxonomic study of 14 isolates recovered from various human and veterinary clinical samples was performed. Phenotypically these isolates shared several characteristics with members of the Alcaligenaceae and related genera. Random amplified polymorphic DNA fingerprinting and whole-cell protein analysis suggested the presence of multiple genomic groups, which was confirmed by DNA–DNA hybridization experiments. 16S rRNA gene sequence analysis indicated that these isolates were related to the genera Pelistega, Taylorella, Oligella, Pigmentiphaga, Alcaligenes, Kerstersia, Achromobacter and Bordetella and belonged to the family Alcaligenaceae. Based on the results of the present study the organisms were classified in a novel genus, Advenella gen. nov. This genus comprises one named species, Advenella incenata sp. nov. (type strain LMG 22250T=CCUG 45225T) and five currently unnamed genomic species. The DNA G+C content of members of the novel genus Advenella is between 54·0 and 57·7 mol%.
|
|
| 17. |
- Coseri, Sergiu, et al.
(författare)
-
Correction : One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate
- 2015
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:117, s. 96927-
-
Tidskriftsartikel (refereegranskat)abstract
- Correction for ‘One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate’ by Sergiu Coseri et al., RSC Adv., 2015, 5, 85889–85897.The authors regret that the images presented for Fig. 1 and 3 in the original article present incorrect carbohydrate structures. The amended versions of these images, in which the 3-position hydroxyl groups are equatorial rather than axial, are presented below.
|
|
| 18. |
- Coseri, Sergiu, et al.
(författare)
-
One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate
- 2015
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:104, s. 85889-85897
-
Tidskriftsartikel (refereegranskat)abstract
- Water soluble cellulose derivatives are highly required products for many practical purposes, expanding the limited applications of pure cellulose caused by the highly ordered hydrogen bond network and high crystallinity. In this connection, this paper, presents a new approach to obtain water soluble carboxyl-functionalized cellulosic materials, combining two of the most common selective oxidation protocols for cellulose, i.e. nitroxyl mediated reaction and periodate oxidation, in a one-shot reaction. It was found that, under specific reaction conditions, fully oxidized, 2,3,6-tricarboxy cellulose can be obtained in large amounts. The other valuable oxidized fractions were found to possess large amounts of carboxylic groups, as determined by potentiometric titration. 13C-NMR evidenced the presence of three distinctive carboxylic groups in the fully oxidized product, whereas for the partially oxidized samples, 13C CP-MAS solid-state NMR did not detect any carbonyl signals. The oxidized products were characterized by means of FTIR and X-ray photoelectron spectroscopy (XPS). Moreover, the changes of the degree of polymerization occurring after oxidative treatments were viscometrically determined.
|
|
| 19. |
|
|
| 20. |
- Eek, Tom, et al.
(författare)
-
Neural suppression in odor recognition memory
- 2023
-
Ingår i: Chemical Senses. - : Oxford University Press. - 0379-864X .- 1464-3553. ; 48
-
Tidskriftsartikel (refereegranskat)abstract
- Little is known about the neural basis of lower- and higher-order olfactory functions such as odor memory, compared with other sensory systems. The aim of this study was to explore neural networks and correlates associated with 3 functions: passive smelling (PS), odor encoding (OE), and in particular odor recognition memory (ORM). Twenty-six healthy participants were examined using functional magnetic resonance imaging conducted across 3 sessions, one for each function. Independent component analysis revealed a difference between sessions where a distinct ORM component incorporating hippocampus and posterior cingulate showed delayed triggering dissociated from odor stimulation and recognition. By contrasting Hit for ORM (target odors correctly recognized as old) and a combination of PS and detected odors from OE, we found significantly lower activations in amygdala, piriform cortex, insula, thalamus, and the inferior parietal lobule. Region of interest analysis including anterior insula, posterior cingulate gyrus, dentate gyrus, left middle frontal gyrus, amygdala, and piriform cortex demonstrated that Hit were associated with lower activations compared with other memory responses. In summary, our findings suggest that successful recognition of familiar odors (odor familiarity) is associated with neural suppression in the abovementioned regions of interest. Additionally, network including the hippocampus and posterior cingulate is engaged in a postrecognition process. This process may be related to incidental encoding of less familiar and more novel odors (odor novelty) and should be subject for future research.
|
|
| 21. |
- Eek, Tom, et al.
(författare)
-
Odor Recognition Memory in Parkinson's Disease : A Systematic Review
- 2021
-
Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 13
-
Forskningsöversikt (refereegranskat)abstract
- Olfactory impairment is a central non-motor symptom in Parkinson's disease (PD). Previous studies have demonstrated that olfactory dysfunction is associated with mental illness and impaired cognition. The frequently investigated olfactory functions are odor detection, discrimination, and identification. However, few studies have focused on odor recognition memory (ORM). ORM tasks involves episodic memory which therefore can facilitate the detection of dementia among patients with PD and consequently adjust their treatment. Thus, the aim of this systematic review is to summarize the existing research on ORM in PD. Databases and reference lists were used for data collection. Studies were included in the review if they met the eligibility criteria derived from the PICOS-framework. Quality evaluation of the studies was based on the STROBE-statement. Six studies with small samples were included in the analysis which demonstrated the scarce research on the subject. The studies targeting ORM were heterogenous and involved two main tasks: odor recognition and odor matching. The synthesis of the data demonstrated that PD patients performed significantly lower than controls on both tasks, especially on odor matching task. Only the odor recognition task exhibited a difference between patients with PD vs. Alzheimer's disease (AD). PD patients performed significantly better than AD patients. The findings based on the available limited data support the notion that odor recognition task can be of importance in identifying Parkinson's disease dementia (PDD). To investigate this hypothesis, future research needs to include larger samples of PD, PDD and AD patients executing the same odor recognition task.
|
|
| 22. |
|
|
| 23. |
- Fernlund, Eva I., et al.
(författare)
-
Serum biomarkers of early stages of hypertrophic cardiomyopathy in a young population
- 2015
-
Ingår i: Journal of the American College of Cardiology. - 0735-1097. ; 65:10S, s. 787-787
-
Konferensbidrag (refereegranskat)abstract
- Background: Hypertrophic cardiomyopathy (HCM) is the most common monogenic cardiac disorder and the leading cause of sudden cardiac death in the young. Although in a majority of HCM cases there are gene mutations coding for sarcomere proteins, the onset for the clinical consequences of these mutations are difficult to predict, as these mutations do not show any clear relationship to the degree of myocardial hypertrophy. Hence identification of early markers for this disease is important. The aim of this study was to investigate novel serum biomarkers reflecting myocardial remodeling, microfibrosis and coronary endotheliopathy in young presymtomatic HCM patients and in individuals at risk for developing HCM. Methods: Eighty-nine participants (18 HCM patients, 14 HCM-risk individuals, and 57 healthy controls) with median age of 15 (range 0-30) years underwent assessment with echocardiography and serum analysis for myostatin, cathepsin S, endostatin, type I collagen degradation marker (ICTP), matrix metalloproteinase (MMP) 9, vascular (VCAM) and intercellular adhesion molecules (ICAM). In some individuals, myocardial perfusion was measured both at rest and after adenosine via magnetic resonance. Results: Both cathepsin S and endostatin were increased in the HCM group (p0.3) and diastolic function, expressed as E/e' (p0.3). In the HCM-risk group, myostatin was decreased (p0.1). Conclusion: To the best of our knowledge, this is the first study to suggest early onset changes in biomarkers of myoblast regulation, endothelial function and matrix remodeling in young presymptomatic HCM patients and in HCM-risk individuals.
|
|
| 24. |
- Forouzanfar, Mohammad H, et al.
(författare)
-
Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks in 188 countries, 1990-2013 : a systematic analysis for the Global Burden of Disease Study 2013.
- 2015
-
Ingår i: The Lancet. - 0140-6736 .- 1474-547X. ; 386:10010, s. 2287-2323
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Global Burden of Disease, Injuries, and Risk Factor study 2013 (GBD 2013) is the first of a series of annual updates of the GBD. Risk factor quantification, particularly of modifiable risk factors, can help to identify emerging threats to population health and opportunities for prevention. The GBD 2013 provides a timely opportunity to update the comparative risk assessment with new data for exposure, relative risks, and evidence on the appropriate counterfactual risk distribution.METHODS: Attributable deaths, years of life lost, years lived with disability, and disability-adjusted life-years (DALYs) have been estimated for 79 risks or clusters of risks using the GBD 2010 methods. Risk-outcome pairs meeting explicit evidence criteria were assessed for 188 countries for the period 1990-2013 by age and sex using three inputs: risk exposure, relative risks, and the theoretical minimum risk exposure level (TMREL). Risks are organised into a hierarchy with blocks of behavioural, environmental and occupational, and metabolic risks at the first level of the hierarchy. The next level in the hierarchy includes nine clusters of related risks and two individual risks, with more detail provided at levels 3 and 4 of the hierarchy. Compared with GBD 2010, six new risk factors have been added: handwashing practices, occupational exposure to trichloroethylene, childhood wasting, childhood stunting, unsafe sex, and low glomerular filtration rate. For most risks, data for exposure were synthesised with a Bayesian meta-regression method, DisMod-MR 2.0, or spatial-temporal Gaussian process regression. Relative risks were based on meta-regressions of published cohort and intervention studies. Attributable burden for clusters of risks and all risks combined took into account evidence on the mediation of some risks such as high body-mass index (BMI) through other risks such as high systolic blood pressure and high cholesterol.FINDINGS: All risks combined account for 57·2% (95% uncertainty interval [UI] 55·8-58·5) of deaths and 41·6% (40·1-43·0) of DALYs. Risks quantified account for 87·9% (86·5-89·3) of cardiovascular disease DALYs, ranging to a low of 0% for neonatal disorders and neglected tropical diseases and malaria. In terms of global DALYs in 2013, six risks or clusters of risks each caused more than 5% of DALYs: dietary risks accounting for 11·3 million deaths and 241·4 million DALYs, high systolic blood pressure for 10·4 million deaths and 208·1 million DALYs, child and maternal malnutrition for 1·7 million deaths and 176·9 million DALYs, tobacco smoke for 6·1 million deaths and 143·5 million DALYs, air pollution for 5·5 million deaths and 141·5 million DALYs, and high BMI for 4·4 million deaths and 134·0 million DALYs. Risk factor patterns vary across regions and countries and with time. In sub-Saharan Africa, the leading risk factors are child and maternal malnutrition, unsafe sex, and unsafe water, sanitation, and handwashing. In women, in nearly all countries in the Americas, north Africa, and the Middle East, and in many other high-income countries, high BMI is the leading risk factor, with high systolic blood pressure as the leading risk in most of Central and Eastern Europe and south and east Asia. For men, high systolic blood pressure or tobacco use are the leading risks in nearly all high-income countries, in north Africa and the Middle East, Europe, and Asia. For men and women, unsafe sex is the leading risk in a corridor from Kenya to South Africa.INTERPRETATION: Behavioural, environmental and occupational, and metabolic risks can explain half of global mortality and more than one-third of global DALYs providing many opportunities for prevention. Of the larger risks, the attributable burden of high BMI has increased in the past 23 years. In view of the prominence of behavioural risk factors, behavioural and social science research on interventions for these risks should be strengthened. Many prevention and primary care policy options are available now to act on key risks.FUNDING: Bill & Melinda Gates Foundation.
|
|
| 25. |
|
|
| 26. |
- Frese, Udo, et al.
(författare)
-
A multilevel relaxation algorithm for simultaneous localisation and mapping
- 2005
-
Ingår i: IEEE Transactions on robotics. - 1552-3098 .- 1941-0468. ; 21:2, s. 196-207
-
Tidskriftsartikel (refereegranskat)abstract
- This paper addresses the problem of simultaneous localisation and mapping (SLAM) by a mobile robot. An incremental SLAM algorithm is introduced that is derived from multigrid methods used for solving partial differential equations. The approach improves on the performance of previous relaxation methods for robot mapping because it optimizes the map at multiple levels of resolution. The resulting algorithm has an update time that is linear in the number of estimated features for typical indoor environments, even when closing very large loops, and offers advantages in handling non-linearities compared to other SLAM algorithms. Experimental comparisons with alternative algorithms using two well-known data sets and mapping results on a real robot are also presented
|
|
| 27. |
|
|
| 28. |
- Goldsmith, Paul F., et al.
(författare)
-
Herschel Measurements of Molecular Oxygen in Orion
- 2011
-
Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 737:2, s. 96 (1-17)
-
Tidskriftsartikel (refereegranskat)abstract
- We report observations of three rotational transitions of molecular oxygen (O2) in emission from the H2 Peak 1 position of vibrationally excited molecular hydrogen in Orion. We observed the 487 GHz, 774 GHz, and 1121 GHz lines using the Heterodyne Instrument for the Far Infrared on the Herschel Space Observatory, having velocities of 11 km s–1 to 12 km s–1 and widths of 3 km s–1. The beam-averaged column density is N(O2) = 6.5 × 1016 cm–2, and assuming that the source has an equal beam-filling factor for all transitions (beam widths 44, 28, and 19''), the relative line intensities imply a kinetic temperature between 65 K and 120 K. The fractional abundance of O2 relative to H2 is (0.3-7.3) × 10–6. The unusual velocity suggests an association with a ~5'' diameter source, denoted Peak A, the Western Clump, or MF4. The mass of this source is ~10 Msun and the dust temperature is ≥150 K. Our preferred explanation of the enhanced O2 abundance is that dust grains in this region are sufficiently warm (T ≥ 100 K) to desorb water ice and thus keep a significant fraction of elemental oxygen in the gas phase, with a significant fraction as O2. For this small source, the line ratios require a temperature ≥180 K. The inferred O2 column density sime5 × 1018 cm–2 can be produced in Peak A, having N(H2) sime 4 × 1024 cm–2. An alternative mechanism is a low-velocity (10-15 km s–1) C-shock, which can produce N(O2) up to 1017 cm–2.
|
|
| 29. |
- Gustafsson, Lena, et al.
(författare)
-
Rapid ecological response and intensified knowledge accumulation following a north European mega-fire
- 2019
-
Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 34:4, s. 234-253
-
Forskningsöversikt (refereegranskat)abstract
- Deepened knowledge on response of biota and ecological processes following fire is essential for a future with warmer climate and more disturbances. In 2014 the first mega-fire (13,100 ha) for at least a century in Scandinavia hit south-central Sweden, in a production forest landscape shaped by clearcutting forestry. Ecological dynamics is followed in >20 projects from universities, authorities and citizen science initiatives, rapidly accumulating substantial amounts of data. We outline projects and summarize their results during the first four years, demonstrating a rapid succession of fungi, lichens, vascular plants, birds, mammals, ticks, butterflies, beetles, and drastically altered carbon dynamics. We characterize forest operations including regeneration measures and point to patterns in pest and pathogen infestations. 8,000 ha is set aside for natural succession, with the rest harvested and managed for forest production, offering excellent opportunities for studies on salvage logging effects, already evident for birds. We demonstrate a strong regrowth of deciduous trees, and the protected part will in some decades likely develop into the largest deciduous-dominated area in boreal north Europe outside Russia. Continued studies of biodiversity and ecological processes are urgent for this unique area.
|
|
| 30. |
- Gårdebjer, Sofie, 1985, et al.
(författare)
-
The Babushka concept – An instructional sequence to enhance laboratory learning in science education
- 2017
-
Ingår i: Journal of Education in Science, Environment and Health. - : ISRES Publishing. - 2149-214X. ; 3:2, s. 213-222
-
Tidskriftsartikel (refereegranskat)abstract
- This paper deals with a novel method for improving the traditional “verification” laboratory in science education. Drawing on the idea of integrated instructional units, we describe an instructional sequence which we call the Babushka concept. This concept consists of three integrated instructional units: a start-up lecture, a laboratory session and a wrap-up lecture. Like the Russian nested doll, the sequence has a nested conceptual structure, moving from “bigger” questions to “smaller” ones. The students are actively involved during the lectures by answering reflective questions. This careful sequencing of ideas and activities aims to help the students to relate new ideas to prior knowledge, and to understand the purpose of the laboratory activity. The Babushka concept was implemented in a master’s course in pharmaceutical technology and its impact was evaluated using both qualitative and quantitative methods. The evaluation focused on the students’ perceptions of the intervention as well as their learning gains. A majority of the students found the Babushka concept helpful for their learning and agreed that this concept should be used in other courses. Moreover, the number of correct answers on the final written exam increased by 10%. We briefly discuss one way to enhance the Babushka concept.
|
|
| 31. |
- Hansson, Lars-Olof, et al.
(författare)
-
Comparison between Chicken and Rabbit Antibody Based Particle Enhanced Cystatin C Reagents for Immunoturbidimetry
- 2008
-
Ingår i: Journal of immunoassay & immunochemistry. - : Informa UK Limited. - 1532-1819 .- 1532-4230. ; 29:1, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- We have compared three commercial particle enhanced cystatin C reagents. One of the reagents utilizes chicken antibodies and the other two reagents are rabbit antibody based. We show that the chicken antibody based reagent yields a higher delta absorbance when reacting with the antigen. IgY coupled to latex particles show a strong scatter response even at high antigen concentrations in contrast to the steep decline in scatter previously reported for IgY antibodies in solution. The reagent also showed a low CV for duplicate samples. Laying hens thus seems as an interesting source of antibodies for particle-enhanced immunoassays.
|
|
| 32. |
- Hedman, Daniel, 1989-, et al.
(författare)
-
Impact of training and validation data on the performance of neural network potentials : A case study on carbon using the CA-9 dataset
- 2021
-
Ingår i: Carbon Trends. - : Elsevier. - 2667-0569. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- The use of machine learning to accelerate computer simulations is on the rise. In atomistic simulations, the use of machine learning interatomic potentials (ML-IAPs) can significantly reduce computational costs while maintaining accuracy close to that of ab initio methods. To achieve this, ML-IAPs are trained on large datasets of images, which are atomistic configurations labeled with data from ab initio calculations. Focusing on carbon, we use deep learning to train neural network potentials (NNPs), a form of ML-IAP, based on the state-of-the-art end-to-end NNP architecture SchNet and investigate how the choice of training and validation data affects the performance of the NNPs. Training is performed on the CA-9 dataset, a 9-carbon allotrope dataset constructed using data obtained via ab initio molecular dynamics (AIMD). Our results show that image generation with AIMD causes a high degree of similarity between the generated images, which has a detrimental effect on the performance of the NNPs. But by carefully choosing which images from the dataset are included in the training and validation data, this effect can be mitigated. We conclude by benchmarking our trained NNPs in applications such as relaxation and phonon calculation, where we can reproduce ab initio results with high accuracy.
|
|
| 33. |
|
|
| 34. |
- Jonsson, Niklas, et al.
(författare)
-
Calprotectin as an early biomarker of bacterial infections in critically ill patients : an exploratory cohort assessment
- 2017
-
Ingår i: Criminology & Public Policy. - 1538-6473 .- 1745-9133. ; 19:3, s. 205-213
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Calprotectin is the most abundant protein in the cytosolic fraction of neutrophils, and neutrophil degranulation is a major response to bacterial infections.OBJECTIVES: To assess the value of plasma calprotectin as an early marker of bacterial infections in critically ill patients and compare it with the corresponding values for procalcitonin (PCT), C-reactive protein (CRP) and white blood cell count (WBC).METHODS: We measured daily plasma calprotectin levels in 110 intensive care unit patients using a newly developed turbidimetric assay run on clinical chemistry analysers. The likelihood of infection was determined according to the International Sepsis Forum criteria.RESULTS: Overall, 58 patients (52.7%) developed a suspected or confirmed bacterial infection. Plasma calprotectin predicted such infections within 24 hours with an area under the receiver operating characteristics curve (ROC area) of 0.78 (95% CI, 0.68-0.89). The ROC area for calprotectin was significantly greater than the corresponding ROC areas for WBC (P < 0.001) and PCT (P = 0.02) but only marginally better than the ROC area for CRP (0.71; 95% CI, 0.68-0.89).CONCLUSION: Plasma calprotectin appears to be a useful early marker of bacterial infections in critically ill patients, with better predictive characteristics than WBC and PCT.
|
|
| 35. |
|
|
| 36. |
|
|
| 37. |
- Kassebaum, Nicholas J., et al.
(författare)
-
Global, regional, and national disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE), 1990-2015 : a systematic analysis for the Global Burden of Disease Study 2015
- 2016
-
Ingår i: The Lancet. - 0140-6736 .- 1474-547X. ; 388:10053, s. 1603-1658
-
Tidskriftsartikel (refereegranskat)abstract
- Background Healthy life expectancy (HALE) and disability-adjusted life-years (DALYs) provide summary measures of health across geographies and time that can inform assessments of epidemiological patterns and health system performance, help to prioritise investments in research and development, and monitor progress toward the Sustainable Development Goals (SDGs). We aimed to provide updated HALE and DALYs for geographies worldwide and evaluate how disease burden changes with development. Methods We used results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) for all-cause mortality, cause-specific mortality, and non-fatal disease burden to derive HALE and DALYs by sex for 195 countries and territories from 1990 to 2015. We calculated DALYs by summing years of life lost (YLLs) and years of life lived with disability (YLDs) for each geography, age group, sex, and year. We estimated HALE using the Sullivan method, which draws from age-specific death rates and YLDs per capita. We then assessed how observed levels of DALYs and HALE differed from expected trends calculated with the Socio-demographic Index (SDI), a composite indicator constructed from measures of income per capita, average years of schooling, and total fertility rate. Findings Total global DALYs remained largely unchanged from 1990 to 2015, with decreases in communicable, neonatal, maternal, and nutritional (Group 1) disease DALYs off set by increased DALYs due to non-communicable diseases (NCDs). Much of this epidemiological transition was caused by changes in population growth and ageing, but it was accelerated by widespread improvements in SDI that also correlated strongly with the increasing importance of NCDs. Both total DALYs and age-standardised DALY rates due to most Group 1 causes significantly decreased by 2015, and although total burden climbed for the majority of NCDs, age-standardised DALY rates due to NCDs declined. Nonetheless, age-standardised DALY rates due to several high-burden NCDs (including osteoarthritis, drug use disorders, depression, diabetes, congenital birth defects, and skin, oral, and sense organ diseases) either increased or remained unchanged, leading to increases in their relative ranking in many geographies. From 2005 to 2015, HALE at birth increased by an average of 2.9 years (95% uncertainty interval 2.9-3.0) for men and 3.5 years (3.4-3.7) for women, while HALE at age 65 years improved by 0.85 years (0.78-0.92) and 1.2 years (1.1-1.3), respectively. Rising SDI was associated with consistently higher HALE and a somewhat smaller proportion of life spent with functional health loss; however, rising SDI was related to increases in total disability. Many countries and territories in central America and eastern sub-Saharan Africa had increasingly lower rates of disease burden than expected given their SDI. At the same time, a subset of geographies recorded a growing gap between observed and expected levels of DALYs, a trend driven mainly by rising burden due to war, interpersonal violence, and various NCDs. Interpretation Health is improving globally, but this means more populations are spending more time with functional health loss, an absolute expansion of morbidity. The proportion of life spent in ill health decreases somewhat with increasing SDI, a relative compression of morbidity, which supports continued efforts to elevate personal income, improve education, and limit fertility. Our analysis of DALYs and HALE and their relationship to SDI represents a robust framework on which to benchmark geography-specific health performance and SDG progress. Country-specific drivers of disease burden, particularly for causes with higher-than-expected DALYs, should inform financial and research investments, prevention efforts, health policies, and health system improvement initiatives for all countries along the development continuum.
|
|
| 38. |
|
|
| 39. |
|
|
| 40. |
- Larsson, Karolina, et al.
(författare)
-
Polylactide latex/nanofibrillated cellulose bionanocomposites of high nanofibrillated cellulose content and nanopaper network structure prepared by a papermaking route
- 2012
-
Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 125:3, s. 2460-2466
-
Tidskriftsartikel (refereegranskat)abstract
- Previous attempts to use polylactide (PLA) latex particles and nanofibrillated cellulose (NFC) in papermaking processing have been limited to low NFC content. In the present study, a bionanocomposite material was successfully produced using a PLA latex and NFC. The components were mixed using a wet mixing method and bionanocomposite films were made by filtration followed by hot pressing. In composite materials, the dispersion of the reinforcing component in the matrix is critical for the material properties. Biopolymers such as PLA are non-polar and soluble only in organic solvents; NFC is, however, highly hydrophilic. By utilizing latex, i.e., an aqueous dispersion of biopolymer micro-particles, wet mixing is possible and the problem of aggregation of the hydrophilic nanocellulose in organic solvent is avoided. The properties of the resulting NFC/PLA latex bionanocomposite films were analyzed. Thorough blending resulted in good dispersion of the reinforcing component within the matrix. Adding increasing amounts of NFC improved the Young's modulus, tensile strength, and strain at break of the bionanocomposite material. The increase in the tensile properties was linear with increasing NFC content as a result of the good dispersion. The NFC also improved the thermal stability of the bionanocomposite material.
|
|
| 41. |
- Larsson, Karolina, 1978-
(författare)
-
Taxonomy and Phylogeny of Catenulida (Platyhelminthes) with Emphasis on the Swedish Fauna
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on phylogenetic and taxonomic studies of Catenulida (Platyhelminthes). Catenulida is a group of microscopic free-living worms mainly found in freshwater habitats. The Swedish catenulid fauna was previously virtually unknown. The taxonomy of Catenulida is difficult because of the paucity of good morphological characters, which makes species identification extremely difficult. Molecular phylogenies are inferred from DNA sequences. Based on two molecular markers, 18S rDNA and 28S rDNA, the phylogenetic position of Catenulida has now been well established as the sister group to the rest of the flatworms, Rhabditophora. Within Catenulida there is a basal split between two major clades: Retronectidae + Catenulidae and Stenostomidae. The hypothesis of the marine Retronectidae as the sister group of the limnic Catenulida is rejected. Four molecular markers, 18S rDNA, 28S rDNA, ITS-5.8S and CO1, are used as a backbone to infer phylogeny and to generate hypotheses about species delimitation in Catenulida using parsimony jackknifing and Bayesian analysis. Anokkostenostomum comes out non-monophyletic, and Suomina nested within Catenula, so two new synonymies are proposed: Stenostomum Schmidt, 1848 (Anokkostenostomum Noreña et al. 2005) and Catenula Duges, 1832 (Suomina Marcus, 1945) are proposed. A first report on Swedish freshwater Catenulida are given. A total of 13 species are reported from Sweden. Four of them, all belonging to the taxon Stenostomum are new to science: S. gotlandense n.sp.; S. handoelense n.sp.; S. heebuktense n.sp. and S. steveoi n.sp.
|
|
| 42. |
- Larsson, Lisa, 1987-
(författare)
-
Att sträcka ut sig i staden : En studie om social reproduktion, parkplanering och re-kreation i västra Kungsholmens parker
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Social reproduction is a multifaceted concept that encompasses the practices, processes and places through which individuals and societies reproduce themselves. This thesis examines social reproduction by looking at restorative and relaxing practices and place experiences – what I dub re-creation – in urban parks in Stockholm. It traces how different park planning ideals regulate the practices that support individuals’ social reproduction. The study contrasts modernist parks of the early welfare era (planned throughout the 1930s and 1940s) to contemporary neoliberal, compact city parks (planned over the past two decades), using interviews with 34 park users in western Kungsholmen, as well as an analysis of planning documents and interviews with planning officials. The findings suggest that re-creation in parks involves long walks in nature-like parks that enable reflection, rest, and reproduction necessary for work and other obligations, which can reinforce dominant capitalist social relations. However, re-creation practices are also used to find relief from headwork and social media compulsions. Furthermore, a sense of self is supported by the affectionate bonds that park users develop with various features of the park environment. The study shows that modernist parks are designed to be interconnected and emulate regional landscapes and nature, and are regulated for active re-creation, while compact city parks are more constructed, programmed and delimited by city blocks, with regulation focused on specific activities that emphasize “city life”. The modernist parks are invariably appropriated for re-creation. By contrast, the current trend towards attracting more visitors, activities, and functions in parks, which decreases and fragments park space, compromises re-creation and risks making this form of social reproduction increasingly insecure as urban densification continues. By showing how different park planning ideals influence re-creation practices, the study provides insights that can inform a more nuanced approach to park planning supporting diverse reproductive practices. In particular, the study underscores the need to ensure that parks provide interconnected spaces for active as well as inactive re-creation practices, and that allow individuals to reflect, relax, and reproduce.
|
|
| 43. |
|
|
| 44. |
|
|
| 45. |
- Larsson, Mats, 1953-, et al.
(författare)
-
Risk Management in Early Banking : An International Perspective of Swedish Savings Banks, 1820-1910
- 2021
-
Bok (refereegranskat)abstract
- This book deals with risk management and the organisation of banking in Swedish savings banks alongside the development in other European countries. The period of analysis begins with the establishment of the first savings banks in 1820 and ends in 1910. During this period, banking developed as a well-functioning system for deposits and credits. The book focuses on this development from a theoretical perspective connected to risk management and the role of trust and legitimacy in credits and savings. The analysis deals with the overall development of the Swedish banking system and the role of savings banks as well as bank connections with different groups of customers. Of interest to financial historians, academics, and researchers, it also analyses the role of insider lending and the practical aspects of granting credits, such as the use of collaterals and the level of interest rates to compensate higher risks.
|
|
| 46. |
- Larsson, Mats, 1953-, et al.
(författare)
-
Sweden : Tradition and renewal
- 2018
-
Ingår i: Business Groups in the West. - Oxford : Oxford University Press. - 9780198717973 ; , s. 245-272
-
Bokkapitel (refereegranskat)
|
|
| 47. |
|
|
| 48. |
- Larsson, Per Tomas, et al.
(författare)
-
Bulking method for chemical pulps and its effect on cellulose structure - A CP/MAS 13C-NMR Study
- 2021
-
Ingår i: TAPPICon LIVE. - : TAPPI Press. - 9781713848370 ; , s. 460-464
-
Konferensbidrag (refereegranskat)abstract
- Cellulose-rich never-dried acetate grade Eucalyptus dissolving pulp was used to study the effects on the supramolecular structure of cellulose due to the addition of AlCl3 during drying from acidic conditions (pH 3.5). CP/MAS 13C-NMR was the analytical technique used for taking measures of the cellulose supramolecular structure. In this study AlCl3 was used as source of Al3+, but Al2(SO4)3 has been shown to give the same effect and it is believed that any salt of Al3+ will give the same effect. The presence of AlCl3 increased the average lateral fibril aggregate dimensions some 25% above that reached by the pulp dried without addition of AlCl3. The observed changes in cellulose supramolecular structure due to the addition of AlCl3 are large considering the low AlCl3 concentration that was used. No change in degree of crystallinity was observed as the result of drying, either with or without AlCl3 addition. Although the mechanism of action for AlCl3, causing the observed effects on the cellulose supramolecular structure, is currently not fully understood, the interpretation made was that the presence of AlCl3 increased the agglomeration of the cellulose that always take place during the first drying of cellulosic fibres. This can be seen as an increased degree of physical cross-linking in the cellulose network.
|
|
| 49. |
- Larsson, Per T., et al.
(författare)
-
Fiber length and bonding effects on tensile strength and toughness of kraft paper
- 2018
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 53:4, s. 3006-3015
-
Tidskriftsartikel (refereegranskat)abstract
- Fiber length and fiber-to-fiber bonding effects on tensile strength and fracture toughness of kraft paper have experimentally been investigated. Laboratory sheets were made from kraft pulp, each with a distinct set of fiber lengths. Additionally, the fiber–fiber bond strength was improved by carboxymethyl (CMC) grafting. The tensile strength and work of fracture toughness results were compared to predictions from a shear-lag model which considers the fiber–fiber bond shear strength, the fiber tensile strength and fiber pull-out work. The tensile strength and fracture work for papers with weak fiber–fiber bonds increased with fiber length consistent with the shear-lag model. CMC-treated fibers provided strong fiber–fiber bonds. Papers made from such fibers displayed high strength and work of fracture independent of fiber length which indicates that the failure process is governed by fiber failures rather than bond failures. The fracture toughness, expressed as the critical value of the J-integral, increased strongly with fiber length for both untreated and CMC-treated papers. The results show that long fibers and CMC addition are extremely beneficial for improving the fracture toughness. © 2017, Springer Science+Business Media, LLC.
|
|
| 50. |
- Larsson, R., et al.
(författare)
-
Implementation of adaptive control systems in industrial dry kilns
- 2003
-
Ingår i: Proceedings 8th International IUFRO Wood Drying Conference. - Brasov : Transilvania University of Brasov, Faculty of Wood Industry. ; , s. 397-400
-
Konferensbidrag (refereegranskat)abstract
- Capacity optimisation of Norway spruce, 150x50 mm2 was carried out in a full-scale kiln dryer starting at 50 °C wet bulb temperature. The objective was to reach as high capacity as possible. Maximum allowed moisture content (MC) standard deviation was 10% of the end moisture content value with 2 % maximum allowed amount of checks. An adaptive control strategy for the process control of a kiln dryer was used to optimise the drying process. The temperature drop across the load (TDL) was used to achieve a constant moisture flux from the drying batch. The drying time was 56 h and the total cycle time was 66. 7 h. The end moisture content was 15. 6 % with a standard deviation of 1. 4 %-units. It was concluded that adjustments in TDL due to the amount of heartwood need to be done using this control strategy. Optimising start parameters for different wood species and board dimensions considering maximum allowed checking is important to achieve maximum capacity with this control strategy.
|
|
