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| 2. |
- Berglund, Johan, et al.
(author)
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Surface Topography of Nitrided Steel Surfaces
- 2019
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In: <em>J. Phys.: Conf. Ser.</em>. - : Institute of Physics Publishing.
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Conference paper (peer-reviewed)abstract
- The effect of nitrocarburizing were investigated for two different steels, 42CrMo4 and 25CrMo4, with objective to evaluate the influence of initial surface topography on the resulting nitrocarburized surface with regard to surface topography and thickness of the compound layer. It was found that the nitrocarburizing process has an impact on the surface topography. The process creates a short-wave isotropic structure on the original surface and this is particularly evident for the smoother original surfaces. No significant effect on the compound layer thickness depending on the surface topography before heat treatment could be observed. © Published under licence by IOP Publishing Ltd.
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| 3. |
- Chasoglou, Dimitris, et al.
(author)
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High performance structural PM steel components by means of induction sintering
- 2014
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In: Advances in Powder Metallurgy and Particulate Materials - 2014, Proceedings of the 2014 World Congress on Powder Metallurgy and Particulate Materials, PM 2014. - : Metal Powder Industries Federation. - 9780985339760 ; , s. 56-515
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Conference paper (peer-reviewed)abstract
- In an effort to find alternative routes for the production of sintered parts, induction sintering has been considered a promising candidate because it incorporates short production times. This study is a novel approach which explores the possibility of producing PM steel parts by means of induction sintering. In this work, green compacts from Distaloy-DH powder have been induction sintered at different temperatures and by varying the sintering time and atmosphere. The role and behavior of lubricant and graphite additions during the process were also examined. Conventional sintering was also performed for comparison. Results from the microstructural investigation show complete dissolution of both the diffusion-bonded Cu and the admixed graphite during sintering. Induction sintered samples showed improved mechanical properties which were confirmed by fractographic investigation. The study shows that by careful adjustment of the different sintering parameters it is possible to acquire high performance PM parts through the induction sintering route.
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| 4. |
- Haxton, Eva, et al.
(author)
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One Health education meets science
- 2015
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In: Infection Ecology & Epidemiology. - Uppsala : Informa UK Limited. - 2000-8686. ; 5
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Journal article (other academic/artistic)
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| 5. |
- Hofstetrova, Klara, et al.
(author)
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Giardia intestinalis : Aphidicolin influence on the trophozoite cell cycle
- 2010
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In: Experimental parasitology. - : Elsevier BV. - 0014-4894 .- 1090-2449. ; 124:2, s. 159-166
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Journal article (peer-reviewed)abstract
- This study is a thorough examination of the effects of the DNA polymerase inhibitor aphidicolin on the nuclear cycle and cell cycle progression characteristics, as well as their reversibility, in Giardia intestinalis. Giardia trophozoites are arrested in the G1/S-junction after aphidicolin treatment according to their DNA content. However, cell growth continues and trophozoites arrested with aphidicolin resemble cells in the G2 phase and trophozoites in ageing cultures. Extensive treatment with aphidicolin causes side effects and we detected positive signals for phosphorylated histone H2A, which, in mammalian cells. is involved in a signalling pathway triggered as a reaction to double stranded DNA breaks. These results suggest that aphidicolin causes dissociation of the nuclear and cytoplasmic cycles, a phenomenon that has also been described for other inhibitors in mammalian cell lines. Thus, if aphidicolin is used for synchronization of Giardia trophozoites, this fact must be accounted for, and treatment with aphidicolin must be minimal. (C) 2009 Elsevier Inc. All rights reserved.
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| 6. |
- Johansson, Håkan, 1972-, et al.
(author)
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Characterization of Campylobacter spp. isolated from wild birds in the Antarctic and Sub-Antarctic
- 2018
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:11
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Journal article (peer-reviewed)abstract
- A lack of knowledge of naturally occurring pathogens is limiting our ability to use the Antarctic to study the impact human-mediated introduction of infectious microorganisms have on this relatively uncontaminated environment. As no large-scale coordinated effort to remedy this lack of knowledge has taken place, we rely on smaller targeted efforts to both study present microorganisms and monitor the environment for introductions. In one such effort, we isolated Campylobacter species from fecal samples collected from wild birds in the Antarctic Peninsula and the sub-Antarctic island of South Georgia. Indeed, in South Georgia, we found Campylobacter lari and the closely related Campylobacter peloridis, but also distantly related human-associated multilocus sequence types of Campylobacter jejuni. In contrast, in the Antarctic Peninsula, we found C. tart and two closely related species, Campylobacter subantarcticus and Campylobacter volucris, but no signs of human introduction. In fact, our finding of human-associated sequence types of C. jejuni in South Georgia, but not in the Antarctic Peninsula, suggests that efforts to limit the spread of infectious microorganisms to the Antarctic have so far been successful in preventing the introduction of C. jejuni. However, we do not know how it came to South Georgia and whether the same mode of introduction could spread it from there to the Antarctic Peninsula.
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| 7. |
- Klotz, Christian, et al.
(author)
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Extensive testing of a multi-locus sequence typing scheme for Giardia duodenalis assemblage A confirms its good discriminatory power
- 2022
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In: Parasites & Vectors. - : BioMed Central (BMC). - 1756-3305. ; 15
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Journal article (peer-reviewed)abstract
- Background: The flagellated parasite Giardia duodenalis is a major and global cause of diarrhoeal disease. Eight genetically very distinct groups, known as assemblages A to H, have been recognized in the G. duodenalis species complex, two of which (assemblages A and B) infect humans and other mammalian hosts. Informative typing schemes are essential to understand transmission pathways, characterize outbreaks and trace zoonotic transmission. In this study, we evaluated a published multi-locus sequence typing (MLST) scheme for G. duodenalis assemblage A, which is based on six polymorphic markers.Methods: We genotyped 60 human-derived and 11 animal-derived G. duodenalis isolates collected in Europe and on other continents based on the published protocol. After retrieving previously published genotyping data and excluding isolates whose sequences showed allelic sequence heterozygosity, we analysed a dataset comprising 146 isolates.Results: We identified novel variants at five of the six markers and identified 78 distinct MLST types in the overall dataset. Phylogenetic interpretation of typing data confirmed that sub-assemblage AII only comprises human-derived isolates, whereas sub-assemblage AI comprises all animal-derived isolates and a few human-derived isolates, suggesting limited zoonotic transmission. Within sub-assemblage AII, isolates from two outbreaks, which occurred in Sweden and Italy, respectively, had unique and distinct MLST types. Population genetic analysis showed a lack of clustering by geographical origin of the isolates.Conclusion: The MLST scheme evaluated provides sufficient discriminatory power for epidemiological studies of G. duodenalis assemblage A.
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| 8. |
- Kohne, Thomas, 1990-, et al.
(author)
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Impact of Cooling Rate during High-Pressure Gas Quenching on Fatigue Performance of Low Pressure Carburized Gears
- 2022
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In: Metals. - : MDPI AG. - 2075-4701. ; 12:11, s. 1917-1917
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Journal article (peer-reviewed)abstract
- The impact of cooling rate during high-pressure gas quenching on the fatigue performance of low-pressure carburized spur gears was studied for steel grades 20MnCr5 and 17NiCrMo6-4. The results show an increased fatigue limit by 10 to 11% when applying a slower cooling rate for both steel grades. Moreover, for 20MnCr5 the slower cooled gears show an increase in compressive residual stresses by 130 MPa compared to the faster cooling, although no significant difference was observed for 17NiCrMo6-4. It is also seen that the cooling rate affects the core hardness for both steel grades, while other properties like surface hardness, case-hardness depth and martensite variant pairing were unaffected. The results for the retained austenite content and average martensite unit size show no clear effect of the cooling rate. The possible influence of different carbon distributions after quenching for the two used cooling rates on the carbide precipitation and fatigue limit is discussed. View Full-Text
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| 9. |
- Kristoffersen, Hans, et al.
(author)
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A complete system for testing and evaluation of quenchants and quenching systems
- 2009
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In: Journal of ASTM International. - 1546-962X. ; 6:3
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Journal article (peer-reviewed)abstract
- The quenching operation is a very critical part of the heat treatment process. Improper quenching parameters and drifting of the cooling characteristics during the working life of the quenchant will influence the quenching results. Sophisticated computer-based tools have made It possible to monitor, evaluate, and perform a continuous quality control of the quenchants' and the quenching systems' performance. The increasing and ever more sophisticated use of FEM simulation In order to optimize products and processes means that there Is also a growing need for accurate input data. In quenching simulations, the boundary conditions expressed as heat transfer coefficients based on measured cooling curves are of great importance In order to obtain accurate calculations. One system that offers these features is the ivf SmartQuench®system (SQ).4 This system encompasses data acquisition and a software module for analyzing the cooling curves. With the new, extended software module that was introduced in 2007, SQintegra (SQi), 4 It is now possible for the user to calculate heat transfer coefficients (e.g., for the ISO 9950 probe), as well as hardness and microstructure in a cross section of steel samples. Heat transfer calculations are made on the basis of an inverse analysis of the recorded cooling curve. The result is used as input for the calculation of microstructural constituents and the hardness profile of cylindrical samples of arbitrary diameter. Calculations can be made for several different steel grades. The system can be used for quality control of quenchants, troubleshooting, process follow-up, calculation of heat transfer coefficients, hardness calculations compared to verifying tests, and sensitivity analyses of quenchants. The system has also been used to evaluate the cooling performance In showers used for quenching after induction heating. The process window for a specific quenching shower was established for a polymer quenchant. Factors considered were flow rate, concentration and temperature of the quenchant. Copyright © 2009 by ASTM International.
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| 10. |
- Sandholt, Arnar K. S., et al.
(author)
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Dual RNA-seq transcriptome analysis of caecal tissue during primary Eimeria tenella infection in chickens
- 2021
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In: BMC Genomics. - : BioMed Central (BMC). - 1471-2164. ; 22
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Journal article (peer-reviewed)abstract
- Background: Coccidiosis is an infectious disease with large negative impact on the poultry industry worldwide. It is an enteric infection caused by unicellular Apicomplexan parasites of the genus Eimeria. The present study aimed to gain more knowledge about interactions between parasites and the host immune system during the early asexual replication phase of E. tenella in chicken caeca. For this purpose, chickens were experimentally infected with E. tenella oocysts, sacrificed on days 1-4 and 10 after infection and mRNA from caecal tissues was extracted and sequenced.Results: Dual RNA-seq analysis revealed time-dependent changes in both host and parasite gene expression during the course of the infection. Chicken immune activation was detected from day 3 and onwards with the highest number of differentially expressed immune genes recorded on day 10. Among early (days 3-4) responses up-regulation of genes for matrix metalloproteinases, several chemokines, interferon (IFN)-gamma along with IFN-stimulated genes GBP, IRF1 and RSAD2 were noted. Increased expression of genes with immune suppressive/regulatory effects, e.g. IL10, SOCS1, SOCS3, was also observed among early responses. For E. tenella a general up-regulation of genes involved in protein expression and energy metabolism as well as a general down-regulation genes for DNA and RNA processing were observed during the infection. Specific E. tenella genes with altered expression during the experiment include those for proteins in rhoptry and microneme organelles.Conclusions: The present study provides novel information on both the transcriptional activity of E. tenella during schizogony in ceacal tissue and of the local host responses to parasite invasion during this phase of infection. Results indicate a role for IFN-gamma and IFN-stimulated genes in the innate defence against Eimeria replication.
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