| 1. |
- Loftsdottir, Heidur, et al.
(författare)
-
Dynamics of insertion sequence element IS629 inactivation of verotoxin 2 genes in Escherichia coli O157:H7
- 2017
-
Ingår i: FEMS Microbiology Letters. - : Oxford University Press. - 0378-1097 .- 1574-6968. ; 364:8
-
Tidskriftsartikel (refereegranskat)abstract
- There are several anecdotal reports of insertion sequence (IS) element inactivation of verotoxin genes among enterohaemorrhagic Escherichia coli of the serotype O157:H7, a pathogen causing severe gastrointestinal disease in infected humans. These insertions can be expected to drastically reduce the virulence of the bacteria. IS element inactivation has been shown to be reversible in model systems, suggesting the possibility of spontaneous restoration of virulence. In this study, traditional and high-throughput sequencing was used to characterise three patterns of IS629 inactivation of verotoxin 2 genes in EHEC O157:H7, caused by insertion or insertion followed by partial deletion. At least one of the patterns of inactivation appears to have persisted several years among cattle O157:H7, indicating it has no major effect on fitness in the animal reservoir. Digital PCR was used to directly quantify the reversal rates of the insertional inactivation of a selected isolate under laboratory conditions. Inserts were found to be absent from in the order of 1/10(5) of individual genomes, with significantly higher loss frequencies observed in cultures under nutrient-poor conditions. We conclude that strains with this type of inactivation found in food or animal samples should be considered a threat to human health, and may pose a challenge for PCR-based detection methods.
|
|
| 2. |
- Brinkfeldt, Klas, et al.
(författare)
-
Feasibility of PCB-integrated vibration sensors for condition monitoring of electronic systems
- 2018
-
Ingår i: ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018. - 9780791851920
-
Konferensbidrag (refereegranskat)abstract
- The increasing complexity of electronics in systems used in safety critical applications, such as for example self-driving vehicles requires new methods to assure the hardware reliability of the electronic assemblies. Prognostics and Health Management (PHM) that uses a combination of data-driven and Physics-of-Failure models is a promising approach to avoid unexpected failures in the field. However, to enable PHM based partly on Physics-of-Failure models, sensor data that measures the relevant environment loads to which the electronics is subjected during its mission life are required. In this work, the feasibility to manufacture and use integrated sensors in the inner layers of a printed circuit board (PCB) as mission load indicators measuring impacts and vibrations has been investigated. A four-layered PCB was designed in which piezoelectric sensors based on polyvinylidenefluoride-co-trifluoroethylene (PVDF-TrFE) were printed on one of the laminate layers before the lamination process. Manufacturing of the PCB was followed by the assembly of components consisting of BGAs and QFN packages in a standard production reflow soldering process. Tests to ensure that the functionality of the sensor material was unaffected by the soldering process were performed. Results showed a yield of approximately 30 % of the sensors after the reflow soldering process. The yield was also dependent on sensor placement and possibly shape. Optimization of the sensor design and placement is expected to bring the yield to 50 % or better. The sensors responded as expected to impact tests. Delamination areas were present in the test PCBs, which requires further investigation. The delamination does not seem to be due to the presence of embedded sensors alone but rather the result of a combination of several factors. The conclusion of this work is that it is feasible to embed piezoelectric sensors in the layers of a PCB.
|
|
| 3. |
- Brinkfeldt, Klas, et al.
(författare)
-
Feasibility of Printed Circuit Board-Integrated Vibration Sensors for Condition Monitoring of Electronic Systems
- 2019
-
Ingår i: Journal of Electronic Packaging. - : American Society of Mechanical Engineers (ASME). - 1043-7398 .- 1528-9044. ; 141:3
-
Tidskriftsartikel (refereegranskat)abstract
- The increasing complexity of electronics in systems used in safety critical applications, such as self-driving vehicles, requires new methods to assure the hardware reliability of the electronic assemblies. Prognostics and health management (PHM) that uses a combination of data-driven and physics-of-failure models is a promising approach to avoid unexpected failures in the field. However, to enable PHM based partly on physics-of-failure models, sensor data that measure the relevant environment loads to which the electronics are subjected during its mission life are required. In this work, the feasibility to manufacture and use integrated sensors in the inner layers of a printed circuit board (PCB) as mission load indicators measuring impacts and vibrations has been investigated. A four-layered PCB was designed in which piezoelectric sensors based on polyvinylidenefluoride-co-trifluoroethylene (PVDF-TrFE) were printed on one of the laminate layers before the lamination process. Manufacturing of the PCB was followed by the assembly of components consisting of ball grid arrays (BGAs) and quad flat no-leads (QFN) packages in a standard production reflow soldering process. Tests to ensure that the functionality of the sensor material was unaffected by the soldering process were performed. Results showed a yield of approximately 30% of the sensors after the reflow soldering process. The yield was also dependent on sensor placement and possibly shape. Optimization of the sensor design and placement is expected to bring the yield to 50% or better. The sensors responded as expected to impact tests. Delamination areas were present in the test PCBs, which requires further investigation. The delamination does not seem to be due to the presence of embedded sensors alone but rather the result of a combination of several factors. The conclusion of this work is that it is feasible to embed piezoelectric sensors in the layers of a PCB.
|
|
| 4. |
- Kristensson, Per, 1969-, et al.
(författare)
-
Influencing consumers to choose environment friendly offerings : Evidence from field experiments
- 2017
-
Ingår i: Journal of Business Research. - : Elsevier. - 0148-2963 .- 1873-7978. ; 76, s. 89-97
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this article is to examine a set of ways to influence consumer behavior toward making more environmentally friendly choices. We conducted three different studies to investigate (1) what consumers think would influence their behavior, (2) how several question-based verbal influence strategies nudge consumer behavior in one direction or another, and (3) how question-based written influence strategies influence consumer behavior. The findings reveal a discrepancy between what consumers think would influence behavior and what actually does influence it. In addition, under all verbal and written experimental conditions, influence strategies led to consumer change toward environmentally friendly offerings compared with alternative non-environment friendly offerings. The discussion highlights possible explanations for the results, managerial implications, the study's limitations, and suggestions for future research, with a special emphasis on research into factors that can change consumer behavior.
|
|
| 5. |
- Söderlund, Magnus, et al.
(författare)
-
The allure of the bottle as a package: an assessment of perceived effort in a packaging context
- 2017
-
Ingår i: Journal of Product and Brand Management. - : Emerald. - 1061-0421. ; 26:1, s. 91-100
-
Tidskriftsartikel (refereegranskat)abstract
- This paper aims to assess the impact of perceived effort related to packaging on overall product evaluations. Perceived effort, defined as the consumer’s perceptions of how much manufacturer effort that lies behind an offer, is assumed to contribute to evaluations by signaling unobservable characteristics of an offer.Design/methodology/approachThree between-subjects experiments were conducted with soft drink bottles, which were subject to variation in perceived effort.FindingsThe results show that perceived effort was positively associated with overall evaluations. The results also show that the impact of perceived effort was mediated by product quality perceptions, which indicates that effort signals quality.Originality/valuePerceived effort has to date not been examined in the packaging literature. The present findings thus imply that models of packaging characteristics and their impact on consumers would benefit from including the effort aspect.
|
|
| 6. |
- Söderlund, Robert, et al.
(författare)
-
Genomic comparison of Escherichia coli serotype O103:H2 isolates with and without verotoxin genes: implications for risk assessment of strains commonly found in ruminant reservoirs
- 2016
-
Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Escherichia coli O103:H2 occurs as verotoxigenic E. coli (VTEC) carrying only vtx1 or vtx2 or both variants, but also as vtx-negative atypical enteropathogenic E. coli (aEPEC). The majority of E. coli O103:H2 identified from cases of human disease are caused by the VTEC form. If aEPEC strains frequently acquire verotoxin genes and become VTEC, they must be considered a significant public health concern. In this study, we have characterized and compared aEPEC and VTEC isolates of E. coli O103:H2 from Swedish cattle. Methods: Fourteen isolates of E. coli O103:H2 with and without verotoxin genes were collected from samples of cattle feces taken during a nationwide cattle prevalence study 2011-2012. Isolates were sequenced with a 2 x 100 bp setup on a HiSeq2500 instrument producing >100 x coverage per isolate. Single-nucleotide polymorphism (SNP) typing was performed using the genome analysis tool kit (GATK). Virulence genes and other regions of interest were detected. Susceptibility to transduction by two verotoxin-encoding phages was investigated for one representative aEPEC O103:H2 isolate. Results and Discussion: This study shows that aEPEC O103:H2 is more commonly found (64%) than VTEC O103:H2 (36%) in the Swedish cattle reservoir. The only verotoxin gene variant identified was vtx1a. Phylogenetic comparison by SNP analysis indicates that while certain subgroups of aEPEC and VTEC are closely related and have otherwise near identical virulence gene repertoires, they belong to separate lineages. This indicates that the uptake or loss of verotoxin genes is a rare event in the natural cattle environment of these bacteria. However, a representative of a VTEC-like aEPEC O103:H2 subgroup could be stably lysogenized by a vtx-encoding phage in vitro.
|
|
| 7. |
- Söderlund, Robert, et al.
(författare)
-
Prevalence and genomic characteristics of zoonotic gastro-intestinal pathogens and ESBL/pAmpC producing Enterobacteriaceae among Swedish corvid birds
- 2019
-
Ingår i: Infection Ecology & Epidemiology. - : Taylor & Francis. - 2000-8686. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Wild birds pose a potential threat to animal and human health by spreading infectious diseases. In the present study, we studied the occurrence of bacterial zoonotic pathogens as well as enterobacteria with transferrable antimicrobial resistance genes among Swedish corvids.Materials and methods: Intestines from 66 jackdaws, crows, rooks and magpies from the vicinity of livestock farms at 14 locations in 7 counties were analysed by direct culture or PCR screening followed by culture. Isolates were investigated by whole-genome sequencing.Results and discussion: Campylobacter jejuni were detected in 82% and Yersinia in 3% of the birds. ESBL-producing E. coli were found in one sample (2%) and carried bla CTX-M-55. No Enterobacteriaceae with transferable carbapenem resistance were identified. No Salmonella or E. coli O157:H7 were found, but PCR analysis for enterohaemorrhagic E. coli virulence genes revealed 35% positive samples for intimin, 9% for verotoxin 1 and 17% for verotoxin 2. C. jejuni isolates from corvids were compared to previously published isolates from Swedish sources by multi-locus sequence typing based on genome sequences. All corvid C. jejuni isolates formed a cluster, intermingled with human and chicken isolates. Our results indicate that C. jejuni is ubiquitous among Swedish corvid birds, with sporadic transmission to poultry and humans.
|
|
